Metabolism - Clinical and Experimental - Articles in Press

Overweight, obesity, and their associations with insulin resistance and β-cell function among Chinese: a cross-sectional study in China - Corrected Proof

2010-07-23

Abstract: The aim of this study was to evaluate the associations of body mass index (BMI) with insulin resistance and β-cell function in subjects with normal glucose tolerance. A cross-sectional study was carried out in Fujian province by multistratified sampling from July 2007 to May 2008. The sample consisted of 2931 subjects aged from 20 to 79 years. The questionnaires, physical examinations, and laboratory tests were obtained from all the participants. The homeostasis model assessment of insulin resistance (HOMA-IR) index was used to estimate insulin sensitivity, insulin secretion was assessed using the HOMA-β index, and β-cell function was quantified as the ratio of the incremental insulin to glucose responses over the first 30 minutes during the oral glucose tolerance test (ΔI30/ΔG30). Another measure was adjusted for insulin sensitivity as it modulates β-cell function ([ΔI30/ΔG30]/HOMA-IR). Associations of BMI with morbidities were estimated using multiple logistic regression analysis. Relationships of BMI to insulin resistance and β-cell function were assessed using multiple linear regression analysis and analysis of covariance. The age- and sex-adjusted prevalence of overweight and obesity was 23.04% (27.44% in men and 18.40% in women) and 2.65% (2.75% in men and 2.55% in women), respectively. After adjustment for covariables, BMI was independently associated with morbidity conditions; and there were increasing trend for odds ratios of morbidities across the BMI categories. There were independent differences for HOMA-IR, HOMA-β, and ΔI30/ΔG30 between the normal-weight, overweight, and obese groups except for (ΔI30/ΔG30)/HOMA-IR. Body mass index was significantly and independently associated with HOMA-IR, HOMA-β, and ΔI30/ΔG30 in the multiple linear regression analysis. Body mass index was an independent risk factor for hypertension, type 2 diabetes mellitus, dyslipidemia, metabolic syndrome, as well as the indexes of insulin resistance and β-cell function. It is imperative that the whole society pay more attention to the identification and intervention of overweight and obesity to prevent obesity-related diseases at the very early stage.

How the “A” to “C” conversion may create a new splice acceptor site? - Corrected Proof

Paola Concolino, Cecilia Zuppi, Ettore Capoluongo — 2010-07-23

We have read with great interest the article by Katsumata et al entitled “Novel intronic CYP21A2 mutation in a Japanese patient with classic salt-wasting steroid 21-hydroxylase deficiency” .

IVS9-9C>A, not IVS9-9A>C, mutation in CYP21A2 causes classic salt-wasting steroid 21-hydroxylase deficiency - Corrected Proof

Noriyuki Katsumata, Takashi Shinagawa, Reiko Horikawa, Kaori Fujikura — 2010-07-23

We thank Dr Concolino et al for their interest and comments regarding our recent publication on a CYP21A2 mutation in Metabolism . Just after online publication of this article, Dr Gonçalves (Centro de Genética Humana, Instituto Nacional de Saúde Dr Ricardo Jorge, Lisboa, Portugal) kindly pointed out our error in designating the mutation. As seen in Fig. 1A, the patient has a homozygous A at the IVS9-9 position ; thus, the mutation should have been designated IVS9-9C>A, not IVS9-9A>C. We already asked the Editor to add an “Erratum” section to correct the designation error, which has come out in the latest version of the article . As discussed by Dr Concolino et al and demonstrated by our in vitro expression study , the IVS9-9C>A, not IVS9-9A>C, mutation creates a novel splice acceptor site and results in classic salt-wasting steroid 21-hydroxylase deficiency.

Hyperhomocysteinemia in patients with acute intermittent porphyria - Corrected Proof

Jordi To-Figueras, Rosa Maria Lopez, Ramon Deulofeu, Carmen Herrero — 2010-07-14

Abstract: Homocysteine is an intermediate of methionine metabolism, and its elevation in tissues is correlated with an increased risk for vascular diseases. We measured homocysteine in plasma of 24 patients with acute intermittent porphyria (AIP) and long-term high excretion of heme precursors. Fifteen (62.5%) presented hyperhomocysteinemia (total homocysteine in plasma >15 μmol/L). No association was found between hyperhomocysteinemia and either urinary excretion of heme precursors or clinical status. All the patients showed normal levels of vitamin B12 and folic acid, but 13 (54%) presented low plasma levels of pyridoxal 5′-phosphate (PLP <15 nmol/L). Cystathionine β-synthase (CBS) catalyzes a major removal pathway of homocysteine and is dependent on both PLP and heme as cofactors. It is hypothesized that, in AIP, CBS reduced hepatic activity resulting from either a low heme status and/or consumptive depletion of PLP due to increased demand by 5-aminolevulinatesynthase hyperactivity can induce hyperhomocysteinemia.

Expression of the selenoprotein S (SELS) gene in subcutaneous adipose tissue and SELS genotype are associated with metabolic risk factors - Corrected Proof

2010-07-12

Abstract: The selenoprotein S (SELS) is a putative receptor for serum amyloid A, and recent studies have suggested that SELS may be a link between type 2 diabetes mellitus and inflammation. Genetic studies of SELS polymorphisms have revealed associations with circulating levels of inflammatory markers and hard end points of cardiovascular disease. In this study, we analyzed SELS expression in subcutaneous adipose tissue and SELS genotype in relation to metabolic risk factors. DNA microarray expression analysis was used to study the expression of SELS in lean and obese siblings from the Swedish Obese Subjects Sib Pair Study. TaqMan genotyping was used to analyze 3 polymorphisms, previously found to be associated with circulating levels of inflammatory markers, in the INTERGENE case-control study of myocardial infarction and unstable angina pectoris. Possible associations between SELS genotype and/or expression with anthropometry and measures of metabolic status were investigated. Real-time polymerase chain reaction was used to analyze the SELS expression in isolated human adipocytes incubated with insulin. In lean subjects, we found correlations between SELS gene expression in subcutaneous adipose tissue and measures of obesity (waist, P = .045; sagittal diameter, P = .031) and blood pressure (diastolic, P = .016; systolic P = .015); and in obese subjects, we found correlations with measures of obesity (body mass index, P = .03; sagittal diameter, P = .008) and glycemic control (homeostasis model assessment of insulin resistance, P = .011; insulin, P = .009) after adjusting for age and sex. The 5227GG genotype was associated with serum levels of insulin (P = .006) and homeostasis model assessment of insulin resistance (P = .007). The expression of SELS increased after insulin stimulation in isolated human adipocytes (P = .008). In this study, we found an association between both SELS gene expression in adipose tissue and SELS genotype with measures of glycemic control. In vitro studies demonstrated that the SELS gene is regulated by insulin in human subcutaneous adipocytes. This study further supports a role for SELS in the development of metabolic disease, especially in the context of insulin resistance.

Lipid overaccumulation and drastic insulin resistance in adult catch-up growth rats induced by nutrition promotion after undernutrition - Corrected Proof

2010-07-12

Abstract: This study was designed to explore the metabolic changes resulting from catch-up growth in adult (CUGA) induced by varying degrees of nutrition promotion after undernutrition and to confirm whether these changes are transient or not. The CUGA models were developed on rats refed on intakes of normal chow or high-fat diet after a period of caloric restriction. The growth of the rats measured by body weight and length stagnated during caloric restriction and then rapidly accelerated following refeeding. Catch-up growth in adult resulted in an increase in intramuscular and intrahepatic lipid content, visceral fat deposition, and insulin resistance, which is consistent with a transient rise in food efficiency during the early stage of refeeding. In addition, ectopic lipid deposition, visceral fat accumulation, and insulin resistance were more severe in rats refed the high-fat diet than rats refed the normal chow. These findings suggest that CUGA induced by rapid nutrition promotion could result in persistent lipid overaccumulation (increased visceral fat and ectopic lipid deposition) and drastic systemic insulin resistance. The effects of CUGA on metabolic characteristics are dependent on the type of diet that is used for refeeding, especially on the amount of fat intake.

Systemic inflammation and the metabolic syndrome among middle-aged community volunteers - Corrected Proof

Anna L. Marsland, Jeanne M. McCaffery, Matthew F. Muldoon, Stephen B. Manuck — 2010-07-12

Abstract: The metabolic syndrome is conceptualized as a clustering of risk factors—including insulin resistance, dyslipidemia, central adiposity, and elevated blood pressure (BP)—that increase the risk for cardiovascular disease and type 2 diabetes mellitus. Recent evidence suggests that markers of systemic inflammation may be included in the definition of the syndrome and play some role in its pathogenesis. In this study, we use a statistical modeling technique, confirmatory factor analysis, to evaluate relationships of systemic inflammation, as measured by plasma concentrations of C-reactive protein and interleukin-6, with the component factors of the metabolic syndrome (insulin resistance, dyslipidemia, central adiposity, and elevated BP) and to examine whether inflammation is a potential common pathway linking established components to the full syndrome. Subjects were 645 community volunteers aged 30 to 54 years (48% male, 82% European American, 18% African American). Consistent with existing literature, structural equation modeling adjusting for age, sex, and race confirmed a higher-order common factor underlying the covariation of insulin resistance, dyslipidemia, adiposity, and BP. Inflammation was positively associated with this common factor, accounting for 54% of its variance and partially mediating statistical aggregation of the component factors comprising the metabolic syndrome. These results were particularly strong for adiposity, raising the possibility that inflammatory processes stimulated by intraabdominal adipose tissue contribute to the development of the metabolic syndrome. The inclusion of inflammatory markers in the clinical definition of metabolic syndrome seems warranted and may improve prognostic assessment of risk of type 2 diabetes mellitus and cardiovascular disease.

Exendin-4 regulates GLUT2 expression via the CaMKK/CaMKIV pathway in a pancreatic β-cell line - Corrected Proof

2010-07-05

Abstract: The GLUT2 glucose transporter plays an important role in glucose-induced insulin secretion in pancreatic β-cells by catalyzing the uptake of glucose into the cell. In this study, we investigated whether exendin-4, a long-acting agonist of glucagon-like peptide–1, mediates stimulatory effects on GLUT2 gene expression through the Ca2+/calmodulin (CaM)-dependent protein kinase IV (CaMKIV) cascade. GLUT2 expression was examined by real-time polymerase chain reaction, Western blot analysis, and a reporter gene assay in rat insulin-secreting INS-1 cells incubated with exendin-4. An increased expression level of GLUT2 protein was noted in response to increasing concentrations of exendin-4, with maximal induction at 10 nmol/L. Real-time polymerase chain reaction analysis similarly revealed a significant increase in the amount of GLUT2 messenger RNA by 10 nmol/L exendin-4. Exendin-4 also stimulated GLUT2 promoter activity in response to increasing exendin-4 concentrations, but failed to do so in the presence of STO-609, a CaMKK inhibitor. We also investigated the effect of the constitutively active form of CaMKK (CaMKKc) on GLUT2 promoter activity. The result is consistent with the observations that CaMKKc/CaMKIV enhanced or up-regulated GLUT2 promoter activity in INS-1 cells. Furthermore, exendin-4 induction of GLUT2 protein expression was significantly suppressed in the cells knocking down the CaMKIV. In summary, activation of the CaMKK/CaMKIV cascade might be required for exendin-4–induced GLUT2 gene transcription, indicating that exendin-4 plays an important role in insulin secretion in pancreatic β-cells.

Epigallocatechin gallate–mediated protection against tumor necrosis factor-α–induced monocyte chemoattractant protein–1 expression is heme oxygenase–1 dependent - Corrected Proof

Yuanyuan Zheng, Michal Toborek, Bernhard Hennig — 2010-06-28

Abstract: Flavonoids have been suggested to protect against atherosclerosis via their antioxidant and anti-inflammatory properties. Heme oxygenase–1 (HO-1) is an enzyme that plays an important role in the vascular system, and its induction may provide a protective role against atherosclerosis. We hypothesize that flavonoids can down-regulate endothelial inflammatory parameters by modulating HO-1–regulated cell signaling. We focused on the role of HO-1 and its major metabolic product, bilirubin, on mechanisms of tumor necrosis factor-α–induced endothelial cell activation and protection by the catechin epigallocatechin gallate (EGCG). Pretreatment with EGCG inhibited the secretion of monocyte chemoattractant protein–1 and the activation of activator protein–1 in porcine aortic endothelial cells stimulated with tumor necrosis factor–α. Moreover, EGCG up-regulated the expression of HO-1 and further induced the secretion of bilirubin. The observed anti-inflammatory effects of EGCG were mimicked by the HO-1 inducer cobalt protoporphyrin and abolished by HO-1 gene silencing. These data suggest that the protective properties of flavonoids, such as EGCG, against endothelial inflammation may be regulated in part though induction of HO-1 and subsequent activator protein–1 signaling.

Association of interleukin-4 promoter polymorphisms in Taiwanese patients with type 2 diabetes mellitus - Corrected Proof

2010-06-28

Abstract: Many factors have been implicated in the onset of type 2 diabetes mellitus (T2DM). Recently, immune response and inflammation were suggested to play certain roles in the development and complications of T2DM. The aim of this study is to investigate the putative correlation between the promoter polymorphisms of interleukin-4 (IL-4), one of the immune-regulatory type 2 helper T-cell cytokines, and T2DM. Genomic DNA from 425 Taiwanese T2DM patients and 148 nondiabetic control study subjects were extracted, and their IL-4 promoter polymorphisms were analyzed by polymerase chain reaction–restriction fragment length polymorphism. Both of the distribution of IL-4 C-589T (P = .013) and C-34T (P = .05) genotypes were significantly different between T2DM patients and control subjects. Significant association between IL-4 C-589T alleles (P = .002) and T2DM, as well as C-34T alleles and T2DM (P =.024), was also identified. In addition, a statistically significant association between homologous IL-4 −589 C/C genotype and lower circulatory high-density lipoprotein cholesterol levels was observed. Our results suggested that IL-4 promoter polymorphisms are associated with T2DM. A significant association between IL-4 −589 C/C genotype and lower circulatory high-density lipoprotein cholesterol level was observed as well. The above results suggested that IL-4 may participate in lipid metabolism and diabetic susceptibility.

Apolipoprotein C-I genotype and serum levels of triglycerides, C-reactive protein and coronary heart disease - Corrected Proof

2010-06-28

Abstract: Apolipoprotein C-I (apoCI) is implicated in lipid metabolism and inflammatory response, both important risk factors for human heart disease. However, most findings come from in vitro or animal studies, whereas data on human apoCI are sparse. To elucidate the role of apoCI in human disease, we analyzed a functional polymorphism in the promoter region of the apoCI gene in relation to blood lipids, C-reactive protein (CRP), coronary artery disease (CAD), and myocardial infarction (MI). Rs11568822 is a 4–base pair insertion/deletion (Ins/Del) polymorphism, and the Ins allele leads to a higher transcription in vitro compared with the Del allele. This polymorphism was analyzed in the Intergene study, a case-control study for CAD (N = 1236), and the Stockholm Heart Epidemiology Program, a case-control study for MI (N = 2774). Subjects homozygous for the Ins genotype had significantly higher serum levels of triglycerides (P = .01 and P = .006) and lower serum levels of CRP (P = .02 and P < .0001) compared with all other subjects in both studies. Similar results were obtained when analyzing only the controls of both studies (P = .002 and P = .0002, triglycerides; P = .002 and P < .0001, CRP). However, apoCI was not associated with CAD or MI. In conclusion, our data show that apoCI genotype is associated with serum levels of triglycerides and CRP, confirming the role of apoCI in lipid metabolism and suggesting that it also influences inflammation.

Stronger associations of sagittal abdominal diameter with atherogenic lipoprotein subfractions than waist circumference in middle-aged US white and Japanese men - Corrected Proof

2010-06-28

Abstract: Both sagittal abdominal diameter (SAD) and waist circumference (WC) highly correlate with visceral adipose tissue (VAT) being linked to an atherogenic lipoprotein profile. However, it is uncertain whether SAD is a better correlate of atherogenic lipoprotein subfractions than WC. We examined relative associations of SAD vs WC with lipoprotein subfractions for US white and Japanese men, concurrently examining the associations of VAT vs subcutaneous adipose tissue with lipoprotein subfractions. A population-based sample of 260 white and 282 Japanese men aged 40 to 49 years was examined for VAT and subcutaneous adipose tissue by computed tomography; SAD and WC by a portable sliding-beam caliper and a measuring tape, respectively; and lipoprotein subfractions by nuclear magnetic resonance spectroscopy. Both SAD and WC were significantly and positively associated with large very low-density lipoprotein and total and small low-density lipoprotein particle concentrations, and inversely associated with large high-density lipoprotein particle concentration for both white and Japanese men. In body mass index–adjusted regression models, the significant associations of SAD remained for both white and Japanese men, whereas those of WC became nonsignificant for white men. When SAD and WC were simultaneously included into the body mass index–adjusted models, the associations of SAD remained significant and statistically stronger than those of WC for both white and Japanese men. Furthermore, the pattern of the associations of SAD with those lipoprotein subfractions was comparable to that of the associations of VAT. Sagittal abdominal diameter was comparable to VAT and stronger than WC in the associations with atherogenic lipoprotein subfractions for middle-aged, nondiabetic, white and Japanese men.

Fenofibrate suppresses microvascular inflammation and apoptosis through adenosine monophosphate–activated protein kinase activation - Corrected Proof

Atsuko Tomizawa, Yoshiyuki Hattori, Teruo Inoue, Sachiko Hattori, Kikuo Kasai — 2010-06-28

Abstract: The Fenofibrate Intervention and Event Lowering in Diabetes study demonstrated that treatment with fenofibrate in individuals with type 2 diabetes mellitus not only reduced nonfatal coronary events but also diminished the need for laser treatment of diabetic retinopathy and delayed the progression of diabetic nephropathy. However, the mechanism by which fenofibrate may have altered the microvasculature remains unclear. We thus investigated the effect of fenofibrate on human glomerular microvascular endothelial cells (HGMEC). Treatment of HGMEC with fenofibrate resulted in transient activation of adenosine monophosphate–activated protein kinase (AMPK), thereby inducing the phosphorylation of Akt and endothelial nitric oxide synthase, leading to nitric oxide production. We compared AMPK activation induced by bezafibrate and WY14643 with that induced by fenofibrate in HGMEC as well as HepG2 cells. Only fenofibrate activated AMPK in HGMEC. Fenofibrate also inhibited nuclear factor–κB activation by advanced glycation end-products, thereby suppressing the expression of various adhesion molecule genes in HGMEC. Suppression of fenofibrate-induced inhibition of nuclear factor–κB activation was observed in cells treated with AMPK small interfering RNA or compound C. Furthermore, fenofibrate was observed to significantly suppress apoptosis of HGMEC in hyperglycemic culture medium. Treatment with compound C or Nw-nitro-L-arginine methyl ester (L-NAME) abolished the suppressive effect of fenofibrate on HGMEC apoptosis. Our findings suggest that fenofibrate might exert a protective effect on the microvasculature by suppressing inflammation and apoptosis through AMPK activation beyond its lipid-lowering actions.

The role of JAZF1 on lipid metabolism and related genes in vitro - Corrected Proof

Ling Li, Yan Yang, Gangyi Yang, Chunming Lu, Mengliu Yang, Hua Liu, Haihong Zong — 2010-06-28

Abstract: JAZF1 is a novel gene that is associated with diabetes mellitus and prostate cancer according to genomewide association studies; however, little is known about the function of this gene in regulating metabolism. In the present study, we have shown the expression of JAZF1 in various mouse tissues. To elucidate its role in metabolism, we investigated the influence of an overexpression of JAZF1 on 3T3-L1 adipose cells and hepatoma carcinoma Hepa1-6 cells that represent target tissues for diabetes and insulin resistance. In both cells, JAZF1 overexpression led to a substantial reduction in the expression of acetyl–coenzyme A carboxylase, fatty acid synthetase, and sterol regulatory element–binding protein 1 messenger RNA (mRNA). The level of hormone-sensitive lipase mRNA significantly increased. The expression of JAZF1 in 3T3-L1 adipocyte exhibited suppressive effects on lipid accumulation and decreased droplet size. In addition, the transcription for glucose transport 1 was significantly higher than the control in the Hepa1-6 cell line; but it was not significantly different in 3T3-L1. These results showed that JAZF1 in adipocytes and liver cells reduces lipid synthesis and increases lipolysis mainly by down-regulating the levels of sterol regulatory element–binding protein 1, acetyl–coenzyme A carboxylase, and fatty acid synthetase mRNA expression and by increasing hormone-sensitive lipase mRNA expression. Because it had an effect on the decrease of the maturation of lipid droplets and fat storage, we speculate that JAZF1 might represent a potential target against diabetes and obesity.

The patterns of glucose tolerance and insulin resistance among rural Chinese twin children, adolescents, and young adults - Corrected Proof

2010-06-28

Abstract: Pubertal insulin resistance (IR) is well recognized; but little data are available for glucose and insulin pattern from a large, unselected lean population. This report describes the age- and sex-specific distributions of glucose tolerance and IR in a rural Chinese twin population. This report includes 4488 subjects aged 6 to 24 years. The primary variables of interest are fasting plasma glucose, 2-hour postload plasma glucose (2-h PG), fasting serum insulin, 2-hour postload insulin, and the homeostatic model assessment for IR. Age- and sex-specific patterns for the primary variables are described using smoothing plot, arithmetic or geometric mean, and percentiles. There is an increase in fasting plasma glucose, 2-h PG, and IR during puberty (10-19 years) and a return to prepuberty level by the age of 20 years. Insulin resistance peaks at around the age of 14 years in girls and 16 years in boys. Two-hour postload plasma glucose and 2-hour postload insulin are higher in girls than in boys from early puberty, and the sex differences are more pronounced afterward. Moreover, the prevalence of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) increases after puberty and is higher in girls than in boys. In this community-based, nonobese rural Chinese twin population, we observed sex-specific remarkable pubertal surge of IR and modest increase in plasma glucose as well as increasing prevalence of IFG and IGT with age. Notably, females had higher 2-h PG and higher prevalence of IFG and IGT. Our study underscored that adolescence (even more so in females) is a critical period for developing IR and prediabetes.

Body fat changes and activity of tumor necrosis factor α system—a 5-year follow-up study - Corrected Proof

2010-06-28

Abstract: Obesity is associated with subclinical, chronic, and systemic immune activation characterized by increased serum concentration of proinflammatory cytokines released by adipose tissue. The aim of the present study was to determine the relationship between stage of development of obesity and changes in activity of tumor necrosis factor (TNF) system during 5-year follow-up observation. One hundred fifty-four women—102 obese, 24 overweight, and 28 lean—without concomitant diseases were examined for the first time from 2000 to 2001. After 5 years, 57 obese, 12 overweight, and 14 lean subjects were reexamined. In addition to anthropometric measurements, body composition was determined by the bioimpedance method; and serum concentrations of glucose, lipids, insulin, TNF-α, and soluble TNF receptors (sTNFRs) were measured. Only reexamined subjects were included in the analysis. After 5 years, fat mass increased significantly in 46 (66.7%) overweight or obese women and in all lean subjects (39.0 ± 12.3 vs 47.3 ± 13.6 kg, P < .001; 14.8 ± 3.7 vs 20.6 ± 5.4 kg, P < .01, respectively), whereas it decreased in 23 (33.3%) overweight or obese subjects (41.3 ± 12.5 vs 37.2 ± 14.0 kg, P < .005). The TNF-α levels increased significantly only in lean women (3.1 ± 3.0 vs 5.6 ± 2.0 pg/mL, P < .005), but remained unchanged in overweight and obese subjects regardless of fat mass changes. Serum concentrations of sTNFR1 and sTNFR2 decreased by 71% and 25% in obese, by 104% and 21% in overweight, and by 31% and 32% in lean group, respectively. The increase of plasma TNF-α level is an early event in abdominal fat accumulation. It seems that further fat mass gain does not enhance circulating TNF-α levels.

Replication of recently described type 2 diabetes gene variants in a South Indian population - Corrected Proof

Manickam Chidambaram, Venkatesan Radha, Viswanathan Mohan — 2010-06-28

Abstract: Recent genomewide association studies have identified several new gene variants associated with type 2 diabetes mellitus (T2D) mostly in European populations. These need to be replicated in other populations. We studied 926 unrelated T2D and 812 normal glucose-tolerant subjects randomly selected from the Chennai Urban Rural Epidemiology Study in Southern India. A total of 45 single nucleotide polymorphisms (SNPs) from 15 genes and 13 unannotated loci identified from recent genomewide association T2D studies were genotyped. Only 6 of 45 SNPs studied were replicated in this South Indian population. Three SNPs—rs7756992 (P = .007), rs7754840 (P = .015), and rs6931514 (P = .029)—of the CDKAL1, rs7020996 (P = .003) of the CDKN2A/B gene, rs7923837 (P = .038) of the HHEX gene, and rs12056034 (P = .033) of the BAZ1B gene were associated with T2D in our population. Large-scale studies are needed in our population to validate our findings.

Serum adiponectin is associated with homocysteine in elderly men and women, and with 5,10-methylenetetrahydrofolate reductase (MTHFR) in a sex-dependent manner - Corrected Proof

2010-06-28

Abstract: Plasma homocysteine associates positively with cardiovascular disease. C-to-T substitution at base 677 of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene associates with increased plasma homocysteine. The association of adiponectin with cardiovascular disease is unclear. This study of survivors of a 30-year cohort of the Jewish Israeli population, 310 men and 273 women (mean age, 70.5 ± 7.0 years for both), investigated the relationship between adiponectin and homocysteine, and between adiponectin and the MTHFR C677T genotype. Serum adiponectin associated positively with total homocysteine in both men (r = 0.27, P < .001) and women (r = 0.22, P < .001). In women, the TT MTHFR genotype associated with lower median adiponectin levels, 8.98 mg/L, compared with 9.88 and 10.57 mg/L for TC and CC, respectively (P = .05; CC vs TT, P = .01). In men, the trend was opposite, but not statistically significant: 7.90, 7.03, and 6.88 mg/L for TT, TC, and CC genotypes, respectively (P = .5). This study demonstrated a positive association between homocysteine and adiponectin in both elderly men and women and a statistically significant association between adiponectin and MTHFR C677T genotypes in women only.

Adding exercise to rosuvastatin treatment: influence on C-reactive protein, monocyte toll-like receptor 4 expression, and inflammatory monocyte (CD14+CD16+) population - Corrected Proof

2010-06-28

Abstract: Statin treatment and exercise training can reduce markers of inflammation when administered separately. The purpose of this study was to determine the effect of rosuvastatin treatment and the addition of exercise training on circulating markers of inflammation including C-reactive protein (CRP), monocyte toll-like receptor 4 (TLR4) expression, and CD14+CD16+ monocyte population size. Thirty-three hypercholesterolemic and physically inactive subjects were randomly assigned to rosuvastatin (R) or rosuvastatin/exercise (RE) groups. A third group of physically active hypercholesterolemic subjects served as a control (AC). The R and RE groups received rosuvastatin treatment (10 mg/d) for 20 weeks. From week 10 to week 20, the RE group also participated in an exercise training program (3d/wk). Measurements were made at baseline (Pre), week 10 (Mid), and week 20 (Post), and included TLR4 expression on CD14+ monocytes and CD14+CD16+ monocyte population size as determined by 3-color flow cytometry. Serum CRP was quantified by enzyme-linked immunosorbent assay. TLR4 expression on CD14+ monocytes was higher in the R group at week 20. When treatment groups (R and RE) were combined, serum CRP was lower across time. Furthermore, serum CRP and inflammatory monocyte population size were lower in the RE group compared with the R group at the Post time point. When all groups (R, RE, and AC) were combined, TLR4 expression was greater on inflammatory monocytes (CD14+CD16+) compared with classic monocytes (CD14+CD16−) at all time points. In conclusion, rosuvastatin may influence monocyte inflammatory response by increasing TLR4 expression on circulating monocytes. The addition of exercise training to rosuvastatin treatment further lowered CRP and reduced the size of the inflammatory monocyte population, suggesting an additive anti-inflammatory effect of exercise.

Association of serum lycopene and brachial-ankle pulse wave velocity with metabolic syndrome - Corrected Proof

Hyun Yang Yeo, Oh Yoen Kim, Hyo Hee Lim, Ji Young Kim, Jong Ho Lee — 2010-06-28

Abstract: Metabolic syndrome (MetS) is known to inversely correlate with antioxidant status. Recently, it has been reported that MetS is associated with arterial stiffness, a composite risk factor for early atherosclerosis. In addition, our recent study for healthy women showed an inverse relationship between arterial stiffness and circulating lycopene. Therefore, this study aimed to investigate the interrelationship between arterial stiffness, antioxidant status, and the risk of MetS. Korean men (N = 299) were subgrouped according to the number of MetS risk factors (RF 0, RF 1-2, RF ≥3). Anthropometric parameters, brachial-ankle pulse wave velocity (baPWV; a marker of arterial stiffness), antioxidants (lycopene, β-carotene, α-tocopherol), lipid profiles, glucose, insulin, and oxidative stress (low-density lipoprotein [LDL] particle size, oxidized LDL) were measured. Corresponding to the number of MetS RF, baPWV (1306 ± 17, 1364 ± 16, and 1420 ± 33 cm/s; P < .001) and insulin resistance (1.5 ± 0.1, 1.9 ± 0.1, and 2.7 ± 0.2; P < .001) gradually increased after adjustment for age, body mass index, smoking, and drinking, whereas serum lycopene among antioxidants and LDL particle size gradually decreased (0.036 ± 0.001, 0.031 ± 0.001, and 0.028 ± 0.001 mmol/L; P = .004 and 23.9 ± 0.1, 23.7 ± 0.1, and 23.3 ± 0.1 nm; P < .001, respectively). Brachial-ankle pulse wave velocity inversely correlated with serum lycopene after adjustment for the above confounders, blood pressure, insulin resistance, and oxidative stress (r = −0.136, P < .05). Oxidative stress markers also significantly correlated with baPWV as well as serum lycopene. Study subjects were divided into 2 groups by the median level of serum lycopene. When serum lycopene was lower than median level (≤0.0294 mmol/L), baPWV was significantly higher in MetS subjects than non-MetS subjects (1436 ± 41 vs 1367 ± 23 cm/s) after adjustment for age, body mass index, smoking, drinking, and oxidative stress (P = .041). However, when serum lycopene levels were high, no statistically significant difference was observed between the 2 subject groups (1386 ± 36 vs 1326 ± 13 cm/s). In conclusion, our result shows the interrelationship between circulating lycopene, baPWV, and MetS. In addition, much enhanced baPWV in MetS may be associated with lower lycopene concentration.

Pedometer use is beneficial for type 2 diabetes mellitus patients if included in educational programs - Corrected Proof

2010-06-28

In a 2008 article in Metabolism, Bjorgaas MR and colleagues studied the effect of pedometers on the spontaneous physical activity increase and its consequent positive metabolic effects in type 2 diabetes mellitus patients.

Enhanced long-chain fatty acid uptake contributes to overaccumulation of triglyceride in hyperinsulinemic insulin-resistant 3T3-L1 adipocytes - Corrected Proof

Ying-Hsiu Lai, Yueh Chien, Ching Fai Kwok, Low-Tone Ho — 2010-06-28

Abstract: The precise pathogenesis of obesity remains controversial. In obesity, diminished adipose glucose utilization suggests that some other substrates may be responsible for the adipose triglyceride (TG) overaccumulation. Here we attempted to evaluate if long-chain fatty acid (LCFA) flux was modulated by a physiologically relevant condition of hyperinsulinemia in 3T3-L1 adipocytes and if the altered LCFA influx might eventually contribute to the TG overaccumulation in obesity. The effects of prolonged insulin exposure to adipocytes on basal, insulin-stimulated LCFA uptake as well as intracellular LCFA metabolism were measured. Prolonged insulin exposure was found to induce insulin resistance (IR) yet enhance basal and insulin-stimulated LCFA uptake in normoglycemic condition, and the addition of high glucose exacerbated these abnormalities of both glucose and LCFA influx. Along with the enhanced LCFA uptake was an increase in the rates of intracellular LCFA deposition and incorporation into TG; but a decrease was found in basal and insulin-suppressive LCFA oxidation, as well as in isoproterenol-induced fatty acid efflux. Inhibition of either phosphatidylinositol 3-kinase or mitogen-activated protein kinase (MAPK) pathway did not prevent the induction of IR, whereas the enhanced basal and insulin-stimulated LCFA uptake was abrogated by inhibition of MAPK pathway. In hyperinsulinemic insulin-resistant 3T3-L1 adipocytes, basal and insulin-stimulated LCFA uptake tends to increase via a MAPK-dependent mechanism. The increment of LCFA influx predominantly accounts for TG overaccumulation, but not for mitochondrial oxidation, and is prone to retain within adipocytes. These findings may interpret the plausible mechanism of pathogenesis for obesity in hyperinsulinemia-associated IR.

Serum levels of vaspin, obestatin, and apelin-36 in patients with nonalcoholic fatty liver disease - Corrected Proof

2010-06-28

Abstract: The novel adipokines vaspin, obestatin, and apelin-36 are associated with insulin resistance and the components of the metabolic syndrome. We assayed circulating levels of these molecules and examined their association with clinical, biochemical, and histologic phenotypes in patients with nonalcoholic fatty liver disease (NAFLD). Serum levels of vaspin, obestatin, and apelin-36 were assayed by enzyme-linked immunosorbent assay in 91 patients with biopsy-proven NAFLD and 81 controls. We analyzed associations between adipokines and the characteristics of patients with NAFLD using multivariable linear regression models. Univariable analysis showed that concentrations of vaspin and apelin-36 were significantly higher in patients with NAFLD than in controls, whereas no differences in obestatin levels were found. Serum vaspin levels showed a statistically significant association with C-reactive protein (r = 0.378, P < .001) and liver fibrosis scores (r = 0.401, P < .001), whereas apelin-36 levels showed a modest association with homeostasis model assessment of insulin resistance (r = 0.204, P < .01). After stepwise linear regression analysis, serum vaspin levels were the only independent predictor of liver fibrosis scores in patients with NAFLD (β = 0.37, t = 3.99, P < .01). Serum vaspin levels are raised in patients with NAFLD regardless of potential confounders and represent an independent predictor of liver fibrosis scores. These findings support further investigation of this novel adipokine in metabolic liver diseases.

Systemic hemodynamics in relation to glucose tolerance: the Health 2000 Survey - Corrected Proof

2010-06-28

Abstract: The influence of impaired glucose metabolism—that is, impaired fasting glucose, impaired glucose tolerance (IGT), and type 2 diabetes mellitus diabetes (DM2)—on systemic hemodynamics is largely unknown. Therefore, we investigated the associations of glucose metabolism disturbances with stroke index (SI), cardiac index, systemic vascular resistance index (SVRI), arterial pulse wave velocity (PWV), and heart rate among Finnish adults (N = 389; mean age, 58.3 ± 7.9 years) participating in the Health 2000 Survey. Systemic hemodynamic parameters were measured using the whole-body impedance cardiography device, and an oral glucose tolerance test (OGTT) was performed to evaluate glucose tolerance status. We found a decreasing trend for SI and increasing trends for SVRI and PWV according to the worsening of glucose tolerance (P for trend < .003 for all). In pairwise comparisons, SI was lower in the impaired fasting glucose group (P = .041) and the IGT group (P < .001) as compared with the normal glucose tolerance (NGT) group. Systemic vascular resistance index was higher in the IGT group (P = .045) and the DM2 group (P = .043) than in the NGT group. Subjects with IGT or DM2 had higher arterial PWV (10.7 ± 0.2 m/s, P < .001 and 11.7 ± 0.5 m/s, P = .001, respectively) than subjects with NGT (9.5 ± 0.1 m/s). Moreover, 2-hour glucose in OGTT was an independent determinant of SVRI and PWV (P < .001 and P = .005, respectively) in multivariable linear regression models. In conclusion, the present study demonstrates that glucose intolerance, even without DM2, associates with several adverse changes in systemic hemodynamics and that 2-hour glucose in OGTT is an independent determinant of SVRI and PWV. These findings support the systematic evaluation of glucose tolerance status in the estimation of cardiovascular risk among the middle-aged population.

Effect of hormone replacement therapy on plasma lipoprotein levels and coronary atherosclerosis progression in postmenopausal women according to type 2 diabetes mellitus status - Corrected Proof

2010-06-28

Abstract: Type 2 diabetes mellitus is associated with dyslipidemia and with an increased risk of coronary heart disease (CHD). Our objective was to compare the effects of hormone replacement therapy (HRT) on plasma lipoproteins and coronary disease progression in postmenopausal women with and without diabetes. Study subjects were participants in the Estrogen Replacement and Atherosclerosis trial, a placebo-controlled, randomized trial of HRT (conjugated equine estrogen 0.625 mg/d with or without medroxyprogesterone acetate 2.5 mg/d) in postmenopausal women with established CHD (mean age, 65 ± 7 years). Plasma remnant lipoprotein levels and high-density lipoprotein (HDL) subpopulation levels were measured at baseline and year 1. Quantitative coronary angiography was assessed at baseline and at follow-up. At baseline, remnant lipoprotein levels were significantly higher and HDL cholesterol (HDL-C) levels were significantly lower in diabetic women than in women without diabetes. Hormone replacement therapy lowered remnant lipoproteins and increased HDL-C and large HDL particle levels in both groups. However, during HRT, levels of these parameters were still significantly worse in diabetic women than in nondiabetic women. A significant interaction between HRT and diabetes status, with greater increases in plasma atheroprotective HDL α1 particles in nondiabetic women than in diabetic women during HRT, was observed. Coronary heart disease progressed significantly more in women with diabetes than in women without diabetes. Our findings indicate that diabetes attenuates the HRT-related increase in atheroprotective HDL α1 particles. Faster progression of coronary atherosclerosis in women with diabetes could be mediated in part by a worse lipoprotein profile in these women than in women without diabetes, both before and during HRT.

Answer to Dr Flaviani - Corrected Proof

Marit Rokne Bjørgaas — 2010-06-21

We are happy to be able to respond to the Letter to the Editor from Dr Alessandra Di Flaviani regarding our previous study published in Metabolism in May 2008 (“Regular use of pedometer does not enhance beneficial outcomes in a physical activity intervention study in type 2 diabetes mellitus”).

Vaspin and visfatin/Nampt are interesting interrelated adipokines playing a role in the pathogenesis of type 2 diabetes mellitus - Corrected Proof

Hala O. El-Mesallamy, Dina H. Kassem, Ebtehal El-Demerdash, Ashraf I. Amin — 2010-06-01

Abstract: Recently, vaspin and visfatin/Nampt have been identified as interesting novel adipokines having insulin-sensitizing and insulin-mimetic effects, respectively. However, the relationship between them has not been elucidated; and their circulating levels in type 2 diabetes mellitus (T2DM) have not been adequately studied. Therefore, this study was designed to investigate whether their levels are altered in Egyptian T2DM patients and to study the correlation of these novel adipokines with each other and with insulin resistance, interleukin-6 (IL-6), and other biochemical parameters. The levels of vaspin, visfatin/Nampt, IL-6, insulin, and other parameters were measured in nonobese and obese T2DM patients together with matched healthy nondiabetic control subjects. Vaspin, visfatin/Nampt, and IL-6 levels were measured by enzyme-linked immunosorbent assay, whereas insulin levels were measured by chemiluminescence technique. Vaspin and visfatin/Nampt levels were found to be significantly elevated in nonobese (1.62 ± 0.22 and 25.9 ± 3.44 ng/mL, respectively) and obese T2DM patients (2.76 ± 0.38 and 45.4 ± 4.60 ng/mL, respectively) compared with control subjects (0.42 ± 0.05 and 9.37 ± 1.98 ng/mL, respectively) at P < .01. In addition, vaspin and visfatin/Nampt levels were found to be significantly positively correlated with each other and with other biochemical parameters. In conclusion, both vaspin and visfatin/Nampt might play an important role in the pathogenesis of T2DM. In addition, the 3 adipokines—vaspin, visfatin/Nampt, and IL-6—are significantly interrelated with each other. Other possible mechanisms of action for vaspin should be considered besides the inhibition of unknown substrate proteases.

High-sensitivity C-reactive protein is associated with hippocampus volume in nondementia patients with type 2 diabetes mellitus - Corrected Proof

2010-05-31

Abstract: The elevated level of high-sensitivity C-reactive protein (HSCRP) is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of HSCRP correlates with hippocampus volume and insulin resistance in nondementia patients with type 2 diabetes mellitus. Subjects included 45 nondementia patients with type 2 diabetes mellitus, who were divided into 2 groups: high-HSCRP group (age, 65 ± 6 years [mean ± SD]; n = 17) and normal-HSCRP group (65 ± 7 years, n = 28). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging voxel-based specific regional analysis system developed for the study of Alzheimer disease (VSRAD), which yields a z score as the end point for assessment of hippocampal volume. The z score was higher in the high-HSCRP group than in the normal-HSCRP group (P < .0001). The fasting plasma glucose (P < .05) and insulin concentrations (P < .0001) and the homeostasis model assessment (HOMA) index (P < .0001) were higher in the high-HSCRP group than in the normal-HSCRP group. Multiple regression analysis showed that HSCRP levels were independently predicted by z score and HOMA index. Our results indicate that the elevated level of HSCRP in Japanese nondementia patients with type 2 diabetes mellitus is characterized by increased hippocampus volume and insulin resistance, and that the z score and HOMA index are independent predictors of HSCRP.

Oxidant balance markers at birth in relation to glycemicand acid-base parameters - Corrected Proof

Johan Verhaeghe, Rita van Bree, Erik Van Herck — 2010-05-31

Abstract: In diabetic pregnancies, suboptimal glycemic control is a risk factor for fetal acidemia and stillbirth. We hypothesized that the diabetic intrauterine milieu (hyperglycemia, hyperinsulinemia, changes in acid-base status) might predispose to oxidative stress. We studied 70 newborns whose mothers had pregestational diabetes (58 with type 1 diabetes mellitus) and 71 control newborns from nondiabetic mothers. Protein carbonyls (PCs), malondialdehyde, and 8-hydroxy-2′deoxyguanosine were measured in umbilical vein plasma as a reflection of protein, lipid, and DNA oxidative damage, respectively; glutathione peroxidase–3 (GPx3), an important circulating antioxidant enzyme, was also assayed. Despite satisfactory glycemic control in the majority of diabetic mothers, their newborns showed higher birth weight and relative hyperglycemia, hyperinsulinemia, and respiratory acidemia. The oxidant balance marker concentrations were not different at the P < .05 level between the 2 groups, and there was no relationship to maternal hemoglobin A1C levels in the diabetic group. However, in the entire sample, increasing glucose levels at birth were related to lower GPx3 and higher PC concentrations; and GPx3 and PC concentrations were inversely correlated. In addition, a depressed pH or larger base-deficit at birth was related to higher PC and 8-hydroxy-2′deoxyguanosine concentrations. In conclusion, oxidant balance markers at birth are not affected by maternal diabetes per se and its long-term glycemic control, yet some markers are acutely tuned to metabolic cues including glucose and the acid-base environment.

An age-dependent diet-modified effect of the PPARγ Pro12Ala polymorphism in children - Corrected Proof

2010-05-26

Abstract: Variation in the peroxisome proliferator–activated receptor γ gene alters the risk for adiposity in adults, with evidence of interaction with diet. We investigated the age-related association between the Pro12Ala variant (rs1801282) and diet in obesity-related traits in children. The Pro12Ala variant was assayed in 2102 young children aged 1 to 6 years and in 794 periadolescent children aged 10 to 12 years of Greek origin. In both cohorts, no differences were found in obesity traits between the Ala allele carriers and Pro/Pro homozygotes. Sex-stratified analysis showed that, in periadolescent boys, Ala carriers exhibited lower measures of skinfolds (triceps: 16.9 ± 6.9 vs 19.4 ± 7.9 mm, P = .01; subscapular: 9.6 ± 4.5 vs 11.2 ± 5.4 mm, P = .02). On the other hand, young girls who were Ala carriers presented higher measures of triceps skinfold thickness (10.5 ± 3.0 vs 9.9 ± 2.8 mm, P = .04). Nominal gene-diet interactions were revealed in periadolescents for saturated fatty acid (SFA) intake and skinfolds (P for interaction = .05). In Pro/Pro homozygous young girls, SFA and total fat (TF) intake was positively associated with higher body mass index (BMI) (P = .01), waist circumference (P = .02), and skinfold thickness (triceps-SFA: P = 10−5, triceps-TF: P = 10−9, subscapular-SFA: P = 10−6, subscapular-TF: P = 10−4). For Pro/Pro homozygotes, unsaturated fat intake was inversely associated with BMI (P = .04) in young girls, and with BMI (P = .03), waist circumference (P = .03), and triceps (P = .02) in periadolescent boys. Our results suggest that adiposity in children is influenced by the Pro12Ala polymorphism in a sex-specific and age-dependent manner. We also demonstrate evidence of an age-dependent gene-diet (SFA, TF) interaction, suggesting that the type of fat intake modifies the effect of the Pro12 allele on obesity-related measures.

Almond consumption improved glycemic control and lipid profiles in patients with type 2 diabetes mellitus - Corrected Proof

2010-05-26

Abstract: Almond consumption is associated with ameliorations in obesity, hyperlipidemia, hypertension, and hyperglycemia. The hypothesis of this 12-week randomized crossover clinical trial was that almond consumption would improve glycemic control and decrease the risk for cardiovascular disease in 20 Chinese patients with type 2 diabetes mellitus (T2DM) (9 male, 11 female; 58 years old; body mass index, 26 kg/m2) with mild hyperlipidemia. After a 2-week run-in period, patients were assigned to either a control National Cholesterol Education Program step II diet (control diet) or an almond diet for 4 weeks, with a 2-week washout period between alternative diets. Almonds were added to the control diet to replace 20% of total daily calorie intake. Addition of approximately 60 g almonds per day increased dietary intakes of fiber, magnesium, polyunsaturated fatty acid, monounsaturated fatty acid, and vitamin E. Body fat determined with bioelectrical impedance analysis was significantly lower in patients consuming almonds (almonds vs control: 29.6% vs 30.4%). The almond diet enhanced plasma α-tocopherol level by a median 26.8% (95% confidence intervals, 15.1-36.6) compared with control diet. Furthermore, almond intake decreased total cholesterol, low-density lipoprotein cholesterol, and the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol by 6.0% (1.6-9.4), 11.6% (2.8-19.1), and 9.7% (0.3-20.9), respectively. Plasma apolipoprotein (apo) B levels, apo B/apo A-1 ratio, and nonesterified fatty acid also decreased significantly by 15.6% (5.1-25.4), 17.4% (2.8-19.9), and 5.5% (3.0-14.4), respectively. Compared with subjects in the control diet, those in the almond diet had 4.1% (0.9-12.5), 0.8% (0.4-6.3), and 9.2% (4.4-13.2) lower levels of fasting insulin, fasting glucose, and homeostasis model assessment of insulin resistance index, respectively. Our results suggested that incorporation of almonds into a healthy diet has beneficial effects on adiposity, glycemic control, and the lipid profile, thereby potentially decreasing the risk for cardiovascular disease in patients with type 2 diabetes mellitus.

Plasma myeloperoxidase is inversely associated with endothelium-dependent vasodilation in elderly subjects with abnormal glucose metabolism - Corrected Proof

2010-05-26

Abstract: Myeloperoxidase (MPO), a biomarker related to inflammation, oxidative stress, and nitric oxide scavenging, has been shown to impair endothelium-dependent vasodilation. Because elevated hydrogen peroxide concentrations in diabetic vessels may enhance MPO activity, we hypothesized that a stronger association of MPO with flow-mediated dilation (FMD) may be found in subjects with abnormal glucose metabolism. Myeloperoxidase concentrations were measured in EDTA plasma samples from participants of a population-based cohort study, including 230 subjects with normal glucose metabolism and 386 with abnormal glucose metabolism. Vascular function was expressed as FMD and nitroglycerin-mediated dilation of the brachial artery. In subjects with abnormal glucose metabolism, MPO was negatively associated with FMD (−20.9 [95% confidence interval {CI}, −41.7 to −0.2] -μm change in FMD per SD increment of MPO). This association remained significant after adjustment for nitroglycerin-mediated dilation (−31.1 [95% CI, −50.0 to −12.3]) and was not attenuated after further adjustment for established risk factors. In subjects with normal glucose metabolism, MPO was not significantly associated with FMD (2.0 [95% CI, −16.0 to 20.0]). In conclusion, in subjects with abnormal glucose metabolism, plasma levels of MPO are inversely associated with endothelium-dependent vasodilation, possibly reflecting enhancement of MPO activity by vascular oxidative stress.

Adeno-associated virus serotypes 7 and 8 outperform serotype 9 in expressing atheroprotective human apoE3 from mouse skeletal muscle - Corrected Proof

2010-05-26

Abstract: Intramuscular injection of adeno-associated viral (AAV) vectors is potentially a safe, minimally invasive procedure for the long-term gene expression of circulating antiatherogenic proteins. Here, we compare secretion and atheroprotective effects of human apoE3 after injection of 3 pseudotyped AAV vectors (AAV2/7, AAV2/8, or AAV2/9), driven by the CMV enhancer/chicken β-actin (CAG) promoter, into skeletal muscle of hyperlipidemic apolipoprotein E–deficient (apoE−/−) mice. Vector viabilities were verified by transducing cultured C2C12 mouse myotubes and assessing secretion of human apoE3 protein. Both hind limb tibialis anterior muscles of female C57BL/6 apoE−/− mice, 2 months old and fed a high-fat diet, were each injected with 1 × 1010 vector genomes of AAV vector. Identical noninjected mice served as controls; and blood was collected at weeks 0, 1, 2, 4, and 13. At termination (13 weeks), the brachiocephalic artery was excised; and after staining sections, plaque morphometry and fractional lipid content were quantified by computerized image analysis. Intramuscular injection of AAV2/7 and AAV2/8 vectors produced up to 2 μg human apoE3 per milliliter plasma, just below the threshold to reverse dyslipoproteinemia. AAV2/9 was notably less effective, mice having a 3-fold lower level of plasma apoE3 at 13 weeks and a 50% greater burden of atherosclerotic plaque lipid in their brachiocephalic arteries. We conclude that although vector refinement is needed to exploit fully apoE3 atheroprotective functions, AAV2/7 and AAV2/8 are promising gene transfer vectors for muscle-based expression of antiatherogenic circulating proteins.

Physical activity is correlated with serum leptin independent of obesity: results of the national surveillance of risk factors of noncommunicable diseases in Iran (SuRFNCD-2007) - Corrected Proof

2010-05-26

Abstract: Reports on the relationship between leptin and physical activity (PA) at the population level are scarce. The present study examined the relationship between serum leptin concentrations and PA in a nationally representative sample of 3001 Iranian adults aged 25 to 64 years. Data of our third national surveillance of risk factors of noncommunicable diseases were analyzed. Using the Global Physical Activity Questionnaire, the duration and intensity of PA were evaluated in 3 domains: work, commuting, and recreation. Total PA was calculated using metabolic equivalents for PA intensity. Serum leptin was measured with an enzyme-linked immunosorbent assay. After adjustment for age, area of residence, smoking, body mass index, and waist circumference, total PA (r = −0.129, P = .038 in men and r = −0.226, P = .006 in women), the duration of vigorous-intensity activity (r = −0.120, P = .044 in men and r = −0.154, P = .019 in women), the duration of moderate-intensity activity (r = −0.114, P = .047 in men and r = −0.160, P = .018 in women), and time spent on sedentary behaviors (r = 0.194, P = .014 in men and r = −0.204, P = .007 in women) were significantly correlated with serum leptin. In both sexes, participants in higher categories of PA had significantly lower serum leptin levels. In conclusion, our results demonstrated an inverse association between leptin concentrations and PA independent of age, sex, smoking, and body adiposity. Our results point to the regulatory effects of PA on serum leptin.

Low-grade inflammation, and dysfunction of high-density lipoprotein and its apolipoproteins as a major driver of cardiometabolic risk - Corrected Proof

Altan Onat, Gülay Hergenç — 2010-05-26

Abstract: Dysfunction of high-density lipoprotein (HDL) particles that even become proinflammatory or lose atheroprotective properties is known through analyses of HDL isolated from diabetic subjects. Recently, high concentrations of HDL or apolipoprotein (apo) A-I in individuals with diabetes or coronary heart disease were found to reveal dysfunction in some population-based studies. Such dysfunction of HDL and its apos A-I, A-II, and C-III has been observed in a general population for the first time among Turkish adults. Functional defectiveness manifested itself by unexpected correlations with inflammatory biomarkers and, in long-term follow-up, by lack of protection against diabetes and coronary heart disease, accounting for the excess incidences in Turks. Female sex was more pronouncedly affected by this process that presumably exists in other ethnicities in South Asia, East Europe, and the Middle East. In contradistinction, in Western and East Asian population, only individuals with glucose intolerance or those at risk for cardiometabolic disease are considered to be or were documented in a review of clinical trials to have been affected by impaired function of HDL. High-density lipoprotein dysfunctionality is closely linked to obesity and low-grade inflammation yet seems to act partly independently of them. Cigarette smoking in overweight women with low-grade inflammation appears to offer limited protection against cardiometabolic risk. The great impact in public health of the dysfunction of protective serum proteins requires individual clinical recognition, appropriate preventive measures, and delineation of management, including with anti-inflammatory drugs.

High levels of whole-body energy expenditure are associated with a lower coupling of skeletal muscle mitochondria in C57Bl/6 mice - Corrected Proof

2010-05-24

Abstract: Considerable variation in energy expenditure is observed in C57Bl/6 mice on a high-fat diet. Because muscle tissue is a major determinant of whole-body energy expenditure, we set out to determine the variation in energy expenditure and its possible association with skeletal muscle mitochondrial function upon high-fat diet intervention. Metabolic cages using indirect calorimetry were used to assess whole-body energy metabolism in C57Bl/6 male mice during the first 3 days of high-fat diet intervention. Mice were grouped in a negative or positive residual nocturnal energy expenditure group after correction of total nocturnal energy expenditure for body mass by residual analysis. The positive residual energy expenditure group was characterized by higher uncorrected total nocturnal energy expenditure and food intake. On day 7, mitochondria were isolated from the skeletal muscle of the hind limb. Mitochondrial density was determined by mitochondrial protein content and did not differ between the positive and negative residual energy expenditure groups. Using high-resolution respirometry, mitochondrial oxidative function was assessed using various substrates. Mitochondria from the positive residual energy expenditure group were characterized by a lower adenosine diphosphate–stimulated respiration and lower respiratory control rates using palmitoyl–coenzyme A as substrate. These results indicate that reduced mitochondrial coupling is associated with positive residual energy expenditure and high rates of total energy expenditure in vivo.

Leptin increases skeletal muscle lipoprotein lipase and postprandial lipid metabolism in mice - Corrected Proof

William T. Donahoo, Nicole R. Stob, Stefen Ammon, Nancy Levin, Robert H. Eckel — 2010-05-24

Abstract: The ability of leptin to preserve lean tissue during weight loss may be in part due to differences in nutrient partitioning. Because lipoprotein lipase (LPL) plays a key role in partitioning lipid nutrients, this study was conducted to test the hypothesis that leptin would modify the tissue-specific regulation of LPL and result in increased lipid oxidation and decreased storage. The effects of daily intraperitoneal leptin injections (2 mg/kg body weight) over 2 weeks on LPL activity and postprandial lipid metabolism were tested in both wild-type (WT), leptin-deficient ob/ob obese mice and mice pair fed to the leptin-treated mice. On the experimental day, mice were given food by gavage, blood was drawn periodically, and adipose tissue and skeletal muscle were harvested for measurements of LPL activity at 240 minutes. After 2 weeks of leptin administration, skeletal muscle LPL (SMLPL) activity was increased in leptin-treated compared with pair-fed (P = .012) and WT (P = .002) mice. There was no effect of leptin or pair feeding on postprandial adipose tissue LPL activity. In ob/ob mice, leptin treatment normalized the decrease in postprandial free fatty acid concentration (P = .066). Leptin had no effect on either the area under the triglyceride (TG) excursion or the integrated area under the TG excursion in WT mice. In ob/ob mice, however, the TG excursion was lower in the leptin-treated than the pair-fed mice by area under the TG excursion (P = .012) and was lower than in the WT mice by integrated area under the TG excursion (P = .027). As expected, 2 weeks of leptin treatment decreased body weight in both the WT and ob/ob mice (−2.6% and −10.4%, respectively). Leptin treatment increased SMLPL, an effect that may have contributed to the leptin-induced weight loss. The leptin-induced decreased postprandial TG excursion in ob/ob mice suggests that leptin acts to augment clearance of postprandial TG-rich lipoprotein lipid and that this increase may in part be secondary to the increased activity of SMLPL. The trend for decreased postprandial free fatty acid may indicate that leptin decreases adipose tissue lipid stores without increasing lipolysis.

Adenosine triphosphate depletion by cyanide results in a Na+-dependent Mg2+ extrusion from liver cells - Corrected Proof

Pranav Dalal, Andrea Romani — 2010-05-24

Abstract: Addition of NaCN to isolated hepatocytes results in a marked and rapid decrease in cellular adenosine triphosphate (ATP) content, and in the extrusion of a sizable amount of cellular Mg2+. This extrusion starts after a 10-minute lag phase and reaches a maximum of 35 to 40 nmol Mg2+ per milligram protein within 60 minutes from the addition of CN−. A quantitatively similar Mg2+ extrusion is also observed after the addition of the mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxy-phenylhydrazone but not that of the glycolysis inhibitor iodoacetate. The Mg2+ extrusion is completely inhibited by the removal of extracellular Na+ or the addition of imipramine, quinidine, or glibenclamide, whereas it persists after the removal of extracellular Ca2+ or K+, or the addition of amiloride. An acidic extracellular pH or the removal of extracellular HCO3− inhibits the cyanide-induced Mg2+ extrusion by at least 80%. Taken together, these data suggest that the decrease in cellular adenosine triphosphate content removes a major Mg2+ complexing agent from the hepatocyte and results in an extrusion of hepatic Mg2+ exclusively through a Na+-dependent exchange mechanism modulated by acidic changes in extracellular pH.

Distribution of C-reactive protein and its association with subclinical atherosclerosis in asymptomatic postmenopausal Chinese women - Corrected Proof

Ruby H.Y. Yu, Suzanne C. Ho, Christopher W.K. Lam, Jean L.F. Woo, Stella S.Y. Ho — 2010-05-24

Abstract: Substantial evidence shows that C-reactive protein (CRP) is associated with atherosclerosis. However, data on the association between CRP and subclinical atherosclerosis are lacking in postmenopausal Chinese women. We aimed to describe the distribution of CRP and its association with metabolic syndrome (MS) and subclinical atherosclerosis in postmenopausal Chinese women in Hong Kong. Between 2002 and 2004, we recruited 518 postmenopausal women aged 50 to 64 years. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. Subclinical atherosclerosis was determined by measuring carotid intima-media thickness (IMT) and plaque (focal wall thickening ≥1.5 mm) using high-resolution B-mode ultrasonography. Median CRP level was 1.00 mg/L. Women with MS had higher median CRP levels than those without MS (1.85 vs 0.80 mg/L, P < .05), and there was a modest trend toward increasing CRP levels with more metabolic components (P for trend < .05). Adjusted for age, hormonal use, and lifestyle factors, women with CRP levels of 0.5 to less than 1.0 mg/L had significantly higher mean IMT compared with those with CRP levels of less than 0.5 mg/L (0.78 vs 0.74 mm, P < .05). Odds ratio for plaque was 1.92 (95% confidence interval, 1.06-3.50) for women with CRP levels of 1.0 to less than 3.0 mg/L compared with those with CRP levels of less than 0.5 mg/L. Further adjustment for MS eliminated the associations. C-reactive protein did not add prognostic value to MS in the prediction of subclinical atherosclerosis. Compared with women without MS and who had CRP levels of less than 3.0 mg/L, those with CRP of at least 3.0 mg/L alone had similar IMT levels (0.75 vs 0.74 mm) and prevalence of plaque (19.4% vs 20.0%). Similarly, women with MS and who had CRP levels of at least 3.0 mg/L had similar IMT levels (0.81 vs 0.81 mm) and prevalence of plaque (30.1% vs 29.7%) compared with those with MS alone. C-reactive protein was strongly associated with MS and its individual components. However, it is not an independent predictor of subclinical atherosclerosis in postmenopausal Chinese women.

Skeletal muscle catabolism in trinitrobenzene sulfonic acid–induced murine colitis - Corrected Proof

2010-05-24

Abstract: The present study determined whether the muscle atrophy produced by colitis is associated with altered rates of muscle protein synthesis or degradation, as well as the potential role of the local (eg, muscle) insulin-like growth factor (IGF) system and muscle-specific ubiquitin E3 ligases atrogin-1 and MuRF1 in mediating altered muscle protein balance. Colitis was induced in C57BL/6 mice by intrarectal administration of trinitrobenzene sulfonic acid (TNBS), and blood and tissues were collected on day 10. Mice with inflammatory bowel disease demonstrated reduced skeletal muscle mass and protein content, whereas colonic segment weight and gross damage score were both increased in mice with colitis, compared with time-matched control values. There was no change in muscle protein synthesis in mice with inflammatory bowel disease; but there was an increased protein breakdown (45%), proteasome activity (85%), and messenger RNA (mRNA) expression for atrogin-1 and MuRF1 (200%-300%) in muscle. These changes were associated with a reduction in liver (but not muscle) IGF-I mRNA as well as a reduction in both total and free IGF-I in the blood. Colitis decreased the hepatic content of IGF binding protein (IGFBP)–3 mRNA by 40% and increased IGFBP-1 mRNA by 100%. In contrast, colitis did alter IGFBP mRNAs in muscle. The tumor necrosis factor–α, interleukin-6, and nitric oxide synthase 2 mRNA content of both liver and skeletal muscle was increased in TNBS-treated mice; and plasma tumor necrosis factor–α and interleukin-6 concentrations were also elevated. These data suggest that TNBS-induced colitis is independent of a change in muscle protein synthesis but dependent on stimulation of protein degradation via increased expression of muscle-specific atrogenes, which may be mediated in part by the reduction in circulating concentration of IGF-I and the concomitant increase in inflammatory mediators observed in the blood and muscle per se.

Changes in adipose-derived inflammatory cytokines and chemokines after successful lifestyle intervention in obese children - Corrected Proof

Christian L. Roth, Mario Kratz, Melissa M. Ralston, Thomas Reinehr — 2010-05-24

Abstract: Obesity has been associated with low-grade chronic systemic inflammation, potentially leading to insulin resistance. This study was designed to examine relationships between cardiovascular risk factors, insulin resistance, and simultaneously measured inflammatory parameters in obese children. We examined serum inflammatory parameters in 115 obese children and 30 normal-weight controls; 62 obese children were followed longitudinally in a 1-year obesity intervention study. Serum concentrations of adipose tissue hormones adiponectin and resistin as well as adipocytokines were assessed. Cross-sectional analysis showed significant correlations between standard deviation score body mass index and resistin (P = .0004) as well as monocyte chemoattractant protein–1 (MCP-1, P = .04). Increased homeostasis model assessment of insulin resistance index greater than 95th percentile was present in 32% of obese patients, correlating with adiponectin (r = −0.40, P = .0007). Significant correlations were found between adiponectin and several mediators of inflammation (interleukins [ILs] IL-1β, IL-6, and IL-8 and tumor necrosis factor–α). In longitudinal analysis, substantial weight loss (change standard deviation score body mass index >0.5) observed after intervention in 29 children was associated with a significant decrease in blood pressure, homeostasis model assessment of insulin resistance index, and serum concentrations of insulin and IL-1β, IL-8, and MCP-1, but increase of adiponectin (all Ps < .05). In 33 children without substantial weight loss, resistin and MCP-1 levels increased after 1 year. Changes in IL-1β correlated positively with changes of weight status, interferon-γ, IL-6, IL-8, and tumor necrosis factor–α (all Ps < .01). Our study demonstrates significant correlations between different metabolic risk factors at baseline and after changes of weight status and that weight loss in obese children reduces low-grade inflammation, insulin resistance, and blood pressure.

Advanced glycation end products, carotid atherosclerosis, and circulating endothelial progenitor cells in patients with end-stage renal disease - Corrected Proof

2010-05-24

Abstract: Numbers of endothelial progenitor cells (EPCs) have been shown to be decreased in subjects with end-stage renal disease (ESRD), the mechanism of which remained poorly understood. In this study, mutual association among circulating EPC levels, carotid atherosclerosis, serum pentosidine, and skin autofluorescence, a recently established noninvasive measure of advanced glycation end products accumulation, was examined in 212 ESRD subjects undergoing hemodialysis. Numbers of circulating EPCs were measured as CD34+ CD133+ CD45low VEGFR2+ cells and progenitor cells as CD34+ CD133+ CD45low fraction by flow cytometry. Skin autofluorescence was assessed by the autofluorescence reader; and serum pentosidine, by enzyme-linked immunosorbent assay. Carotid atherosclerosis was determined as intimal-medial thickness (IMT) measured by ultrasound. Circulating EPCs were significantly and inversely correlated with skin autofluorescence in ESRD subjects (R = −0.216, P = .002), but not with serum pentosidine (R = −0.079, P = .25). Circulating EPCs tended to be inversely associated with IMT (R = −0.125, P = .069). Intimal-medial thickness was also tended to be correlated positively with skin autofluorescence (R = 0.133, P = .054) and significantly with serum pentosidine (R = 0.159, P = .019). Stepwise multiple regression analyses reveal that skin autofluorescence, but not serum pentosidine and IMT, was independently associated with low circulating EPCs. Of note, skin autofluorescence was also inversely and independently associated with circulating progenitor cells. Thus, tissue accumulated, but not circulating, advanced glycation end products may be a determinant of a decrease in circulating EPCs in ESRD subjects.

Hepatic and very low-density lipoprotein fatty acids in obese offspring of overfed dams - Corrected Proof

2010-05-24

Abstract: The combined effects of developmental programming and high-fat feeding at weaning on fatty acid metabolism of the offspring are not well known. In the present study, we aim at characterizing the influence of maternal and offspring's own diets on liver and very low-density lipoprotein (VLDL) lipids; fatty acid profiles of VLDL and liver phospholipids, triglycerides, and cholesteryl esters; and hepatic enzyme activities. Twenty obese male rats born to cafeteria diet–fed dams and 20 control rats born to control diet–fed dams were selected. At weaning, 10 rats of each group were fed control or cafeteria diet. Obese rats had a significant increase in serum glucose, insulin, leptin, VLDL apolipoprotein B100 and lipid levels, and hepatic fatty acid synthase and a reduction in acyl–coenzyme A oxidase and dehydrogenase activities compared with control pups at day 21 and day 90. Hepatic steatosis was apparent only at day 90. The proportions of saturated fatty acids and monounsaturated fatty acids and the oleic to stearic acid ratio were significantly increased, whereas polyunsaturated fatty acids and the arachidonic to linoleic acid ratio were decreased, in liver and VLDL lipids of obese pups compared with controls. The cafeteria diet at weaning induced more severe abnormalities in obese rats. In conclusion, maternal cafeteria diet induced a permanent reduction in hepatic β-oxidation and an increase in hepatic lipogenesis that caused liver steatosis and VLDL and fatty acid alterations in adult offspring. These preexisting alterations in offspring were worsened under a high-fat diet from weaning to adulthood. Nutritional recommendations in obesity must then target maternal and postnatal nutrition, especially fatty acid composition.

Association between functional variants of the ICAM1 and CRP genes and metabolic syndrome in Taiwanese subjects - Corrected Proof

2010-05-24

Abstract: Although inflammation has been shown to play an important role in metabolic syndrome (MetS), the association between inflammatory marker gene polymorphisms and the risk of MetS has not been fully elucidated. This study was initiated to investigate the association between functional variants of inflammatory marker genes and the risk of MetS in Taiwanese adults. The sample population comprised 615 unrelated subjects, of which 22% had MetS. The single nucleotide polymorphisms rs5491 on the intercellular adhesive molecule 1 (ICAM1) gene and rs3091244 on C-reactive protein (CRP) were genotyped. The ICAM1 rs5491 polymorphism was significantly associated with the level of soluble intercellular adhesive molecule 1 (P < .001). Both the ICAM1 rs5491 and the CRP rs3091244 were shown to have significant association with MetS after adjustment for age, sex, smoking, and body mass index, but not after adjustment for levels of the respective serum marker. Independent associations between the combined ICAM1-CRP (rs5491 and rs3091244) genotypes and MetS were found by multivariate analysis (P = .005). In subgroup analysis, association of combined genotypes with insulin resistance and MetS mainly occurred in subjects with central obesity. In conclusion, inflammatory marker gene polymorphisms play an important role in modulating the risk of insulin resistance and MetS for subjects with central obesity. These findings will contribute toward a better understanding of the mechanism of association between inflammatory markers and the risk of developing atherosclerotic disease.

Purine metabolite levels in preovulatory human follicles may hold the key to ovarian hyperstimulation syndrome - Corrected Proof

Ray Kruse Iles, Suzanne M. Docherty — 2010-05-24

We are in agreement with Valerio Napolioni that adenosine's importance in reproductive biology may be wider and more variable than the association with energy charge that we describe. Indeed, we feel that the potent pharmacology of this purine may be unwelcome under emerging circumstances. Tremendous progress has been made in assisted reproductive technology since the birth of the first baby in 1978 by in vitro fertilization (IVF). The development of intracytoplasmic sperm injection in the early 1990s further increased the pregnancy and live birth rates ; nonetheless, a serious iatrogenic illness arose from this technology in the form of ovarian hyperstimulation syndrome (OHSS). This is experienced by approximately 5% to 10% of women undergoing IVF; and the clinical symptoms of OHSS are graded mild, moderate, and severe. Mild symptoms include abdominal bloating and feeling of fullness, nausea, diarrhea, and slight weight gain. The progression to moderate symptoms is defined by excessive weight gain (weight gain of >2 lb/d), increased abdominal girth, vomiting, diarrhea, concentrated urine, and excessive thirst. Severe symptoms are marked abdominal distension due to ascites, pulmonary edema, and chest pain .

ADA (22G>A) polymorphism: a possible genetic marker for predictive medicine of human reproduction? - Corrected Proof

Valerio Napolioni — 2010-05-24

The article by Wen and collaborators published in the Metabolism entitled “High follicular fluid adenosine levels may be pivotal in the metabolism and recycling of adenosine nucleotides in the human follicle” is a very interesting article highlighting the crucial role played by adenosine levels in oocyte survival. This study indicates that functional ADA is absent from the follicular environment of the maturing oocyte. Interestingly, they also suggest that the ova failing to fertilize express ADA (albeit at low levels) and thus alter the composition of the follicular fluid environment by activation of pathways that result in adenine conversion to uric acid; this phenomenon would appear to be detrimental to oocyte viability, leading to the reduction of the energy availability charge of the unfertilized ova at ovulation.

Omentin-1 and vaspin are present in the fetus and neonate, and perinatal concentrations are similar in normal and growth-restricted pregnancies - Corrected Proof

2010-05-20

Abstract: The aim of this study was to investigate circulating concentrations of omentin-1 and vaspin (adipocytokines predominantly secreted by visceral adipose tissue and not yet investigated in perinatal life) in maternal, fetal, and neonatal samples from intrauterine growth-restricted (IUGR; associated with altered development of adipose tissue) and appropriate-for-gestational-age (AGA) pregnancies and to correlate them with the respective insulin concentrations. Serum omentin-1 and vaspin concentrations were determined by enzyme immunoassay in 40 mothers and their 20 IUGR and 20 AGA singleton full-term fetuses and neonates on postnatal day 1 (N1) and day 4 (N4). Both hormones were detectable in fetal and neonatal blood (omentin-1 [mean ± SD, in nanograms per milliliter]: AGA vs IUGR group—fetal: 11.32 ± 1.88 vs 10.47 ± 1.30, N1: 10.74 ± 1.42 vs 10.46 ± 1.54, and N4: 10.90 ± 2.72 vs 11.35 ± 3.92; vaspin [median, minimum-maximum; in nanograms per milliliter]: AGA vs IUGR group—fetal: 0.39 [0.04-19.06] vs 0.40 [0.05-1.34], N1: 0.40 [0.04-16.70] vs 0.44 [0.23-3.34], and N4: 0.49 [0.02-8.89] vs 0.55 [0.06-3.92]). No significant differences in omentin-1 or vaspin concentrations were observed between IUGR and AGA groups, whereas fetal and N1 insulin concentrations were lower in the former (P = .025 and P = .027, respectively). In both groups, fetal omentin-1 concentrations were higher (P ≤ .018), whereas vaspin concentrations were lower (P ≤ .001), than maternal ones. Furthermore, maternal vaspin concentrations were higher in cases of cesarean delivery (P = .024). Omentin-1 and vaspin concentrations did not correlate with the respective insulin ones. In conclusion, omentin-1 and vaspin are present in the fetus and neonate. Perinatal concentrations of omentin-1 and vaspin are similar in IUGR cases and AGA controls—despite lower insulin concentrations in the former—and do not correlate with the respective insulin concentrations. Higher omentin-1 concentrations in the fetus may be crucial to enhance a growth-promoting effect, whereas lower maternal vaspin concentrations in cases of vaginal delivery may be attributed to spontaneous term delivery inflammation.

In utero tobacco exposure epigenetically modifies placental CYP1A1 expression - Corrected Proof

2010-05-12

Abstract: The metabolic pathways used by higher-eukaryotic organisms to deal with potentially carcinogenic xenobiotic compounds from tobacco smoke have been well characterized. Carcinogenic compounds such as polycyclic aromatic hydrocarbons are metabolized sequentially in 2 phases: in phase I, CYP1A1 catalyzes conversion into harmful hydrophilic DNA adducts, whereas in phase II, GSTT1 enables excretion via conjugation into polar electrophiles. In an effort to understand susceptibility to in utero tobacco exposure, we previously characterized known metabolic functional polymorphisms and demonstrated that although deletion of fetal GSTT1 significantly modified birth weight in smokers, no polymorphism fully accounted for fetal growth restriction. Because smoking up-regulates CYP1A1 expression, we hypothesized that nonallelic (epigenetic) dysregulation of placental CYP1A1 expression via alterations in DNA methylation (meCpG) may further modify fetal growth. In the present article, we compared placental expression of multiple CYP family members among gravidae and observed significantly increased CYP1A1 expression among smokers relative to controls (4.4-fold, P < .05). To fully characterize CYP1A1 meCpG status, bisulfite modification and sequencing of the entire proximal 1-kilobase promoter (containing 59 CpG sites) were performed. CpG sites immediately proximal to the 5′-xenobiotic response element transcription factor binding element were significantly hypomethylated among smokers (55.6% vs 45.9% meCpG, P = .027), a finding that uniquely correlated with placental gene expression (r = 0.737, P = .007). Thus, in utero tobacco exposure significantly increases placental CYP1A1 expression in association with differential methylation at a critical xenobiotic response element.

Glucose and protein kinetics in patients undergoing colorectal surgery: perioperative amino acid vs hypocaloric dextrose infusion - Corrected Proof

Andrea Kopp Lugli, Thomas Schricker, Linda Wykes, Ralph Lattermann, Franco Carli — 2010-04-29

Abstract: Surgical injury provokes a stress response that leads to a catabolic state and, when prolonged, interferes with the postoperative recovery process. This study tests the impact of 2 nutrition support regimens on protein and glucose metabolism as part of an integrated approach in the perioperative period incorporating epidural analgesia in 18 nondiabetic patients undergoing colorectal surgery. To test the hypothesis that parenteral amino acid infusion (amino acid group, n = 9) maintains glucose homeostasis while maintaining normoglycemia and reduces proteolysis compared with infusion of dextrose alone (DEX group, n = 9), glucose and protein kinetics were measured before and on the second day after surgery using a stable isotope tracer technique. Postoperatively, the rate of appearance of glucose was higher (P < .001) and blood glucose increased more (P < .001) in the DEX group than in the amino acid group. The postoperative increase in the appearance of leucine from protein breakdown tended to be greater (P = .077) in the DEX group. We conclude that perioperative infusion of a nutrition support regimen delivering amino acids alone maintains blood glucose homeostasis and normoglycemia and tends to have a suppressive effect on protein breakdown compared with infusion of dextrose alone.

Complementation of the metabolic defect in CTP:phosphoethanolamine cytidylyltransferase (Pcyt2)–deficient primary hepatocytes - Corrected Proof

Morgan D. Fullerton, Marica Bakovic — 2010-04-29

Abstract: The CTP:phosphoethanolamine cytidylyltransferase gene (Pcyt2) regulates the synthesis of CDP-ethanolamine, which is combined with diacylglycerol (DAG) to form the membrane phospholipid phosphatidylethanolamine (PE) via the de novo Kennedy pathway. [14C]Ethanolamine and [3H]glycerol radiolabeling experiments established that PE synthesis and turnover are reduced in primary hepatocytes isolated from Pcyt2-deficient (Pcyt2+/−) mice relative to littermate controls. [3H]Glycerol radiolabeling revealed an increased formation of both DAG and triglyceride (TAG) and only increased turnover of DAG, consistent with elevated TAG accumulation. [3H]Acetate radiolabeling showed that de novo fatty acid (FA) synthesis also increased in Pcyt2-deficient hepatocytes. Overexpression of a Myc/His-tagged Pcyt2 complementary DNA into deficient hepatocytes increased Pcyt2 protein expression; normalized PE synthesis and turnover; and reduced FA, DAG, and TAG synthesis. Although increased Pcyt2-myc/His complementary DNA expression normalized lipid homeostasis, a Pcyt2 mutant with 60% catalytic activity (H244Y) was unable to normalize any of the parameters investigated. Only when PE synthesis was fully reestablished did the lipogenic gene expression and the formation of FA, DAG, and TAG revert to the levels of wild-type hepatocytes. These data unambiguously establish that the TAG accumulation present in Pcyt2-deficient hepatocytes is a direct consequence of Pcyt2 gene deficiency and reduced functioning of the de novo Kennedy pathway.