PPARα gene expression correlates with severity and histological treatment response in patients with non-alcoholic steatohepatitis.

BACKGROUND & AIMS: Peroxisome proliferator-activated receptors (PPARs) have been implicated in non-alcoholic steatohepatitis (NASH) pathogenesis, mainly based on animal data. Gene expression data in NASH patients are scarce. We studied liver PPARα, ß/δ, and γ expression in a large cohort of obese patients assessed for presence of NAFLD at baseline and 1 year follow-up. METHODS: Patients presented to the obesity clinic underwent a hepatic work-up. If NAFLD was suspected, liver biopsy was performed. Gene expression was studied by mRNA quantification. Patients were reassessed after 1 year. RESULTS: 125 patients were consecutively included in the study, of which 85 patients had paired liver biopsy taken at 1 year of follow-up. Liver PPARα expression negatively correlated with the presence of NASH (p=0.001) and with severity of steatosis (p=0.003), ballooning (p=0.001), NASH activity score (p=0.008) and fibrosis (p=0.003). PPARα expression was positively correlated to adiponectin (R(2)=0.345, p=0.010) and inversely correlated to visceral fat (R(2)=-0.343, p<0.001), HOMA IR (R(2)=-0.411, p<0.001) and CK18 (R(2)=-0.233, p=0.012). Liver PPARß/δ and PPARγ expression did not correlate with any histological feature nor with glucose metabolism or serum lipids. At 1 year, correlation of PPARα expression with liver histology was confirmed. In longitudinal analysis, an increase in expression of PPARα and its target genes was significantly associated with histological improvement (p=0.008). CONCLUSION: Human liver PPARα gene expression negatively correlates with NASH severity, visceral adiposity and insulin resistance and positively with adiponectin. Histological improvement is associated with an increase in expression of PPARα and its target genes. These data might suggest that PPARα is a potential therapeutic target in NASH.

Genetic and structural variation in the SH2B1 gene in the Belgian population.

OBJECTIVE: Animal studies, genome-wide association and genomic structural variation studies have identified the SH2B1 gene as a candidate gene for obesity. Therefore, we have designed an extensive mutation and copy number variation (CNV) analysis investigating the prevalence of genetic and structural variations in SH2B1 in the Belgian population. DESIGN AND METHODS: In the first part of this study, we performed a mutation screen for variants in the SH2B1 coding region in 581 obese children and adolescents and 433 healthy, lean individuals with high-resolution melting curve analysis followed by direct sequencing. In the second part of this study, Multiplex Amplicon Quantification (MAQ) analysis was used to identify CNVs in the distal SH2B1-containing chr.16p11.2 region in 421 obese children and adolescents with no developmental delay or behavioral phenotype. RESULTS: Mutation analysis resulted in the identification of fifteen rare non-synonymous heterozygous variants. Several of these were found both in lean and obese subjects, suggesting that these are neutral polymorphisms. However, six private, heterozygous, non-synonymous variations were present in obese children only. Furthermore, we also identified six missense variants solely in lean individuals. CNV analysis could not identify carriers of the distal 16p11.2 deletion in our population. CONCLUSION: Our mutation analysis has demonstrated that variation in the SH2B1 gene is frequent in both lean and obese groups, with distinctive variations being present on either side of the weight spectrum. Although the equal variation frequency does not immediately support disease causality, it cannot be excluded that some variations are weight-increasing or -decreasing. Further functional testing of the variants will be necessary to fully understand the impact of these variants on SH2B1. We were not able to detect carriers of the distal 16p11.2 deletion in our study population. As we excluded patients with developmental or behavioral problems, we suggest that in addition to obesity, the distal deletion might predispose for these traits. Further characterization of the phenotype is therefore necessary to clearly identify the phenotype of the distal 16p11.2 microdeletion syndrome.

Prothrombotic factors in histologically proven nonalcoholic fatty liver disease and nonalcoholic steatohepatitis.

UNLABELLED: An independent role of nonalcoholic fatty liver disease (NAFLD) in the development of cardiovascular disease has been suggested, probably mediated through increased levels of prothrombotic factors. Therefore, we examined whether NAFLD is linked to a prothrombotic state, independently of metabolic risk factors in a large single-center cohort of overweight/obese patients. Patients presenting to the obesity clinic underwent a detailed metabolic and liver assessment, including an extensive panel of coagulation factors. If NAFLD was suspected, a liver biopsy was proposed. A series of 273 consecutive patients (65% female) with a liver biopsy were included (age, 44 ± 0.76 years; body mass index: 39.6 ± 0.40 kg/m(2)). Increase in fibrinogen, factor VIII, and von Willebrand factor and decrease in antithrombin III correlated with metabolic features, but not with liver histology. Levels of plasminogen activator inhibitor-1 (PAI-1) increased significantly with increasing severity of steatosis (P < 0.001), lobular inflammation (P < 0.001), ballooning (P = 0.002), and fibrosis (P < 0.001). Patients with nonalcoholic steatohepatitis had significantly higher PAI-1 values than those with normal liver (P < 0.001). In multiple regression, including anthropometric and metabolic parameters, steatosis remained an independent predictor of PAI-1 levels, explaining, together with fasting C-peptide and waist circumference, 21% of the variance in PAI-1. No consistent correlations with histology were found for the other coagulation factors. CONCLUSION: In obesity, NAFLD severity independently contributes to the increase in PAI-1 levels, whereas other coagulation factors are unaltered. This finding might, in part, explain the increased cardiovascular risk associated with NAFLD.

Noninvasive assessment of nonalcoholic fatty liver disease in obese or overweight patients.

BACKGROUND & AIMS: Reliable noninvasive tools are needed for staging nonalcoholic fatty liver disease (NAFLD). Published scoring systems have not been validated in prospective assessments of unselected patients. We aimed to identify factors that predicted development of nonalcoholic steatohepatitis (NASH) in a large group of overweight or obese patients and compared these with established factors. METHODS: We performed a prospective analysis of factors associated with the development and severity of NAFLD in patients at a single obesity center. We evaluated liver involvement in 542 patients by a large set of routine and non-routine parameters, including ultrasound and genetic testing. Those suspected of having NAFLD underwent liver biopsy (57.7%). Patients were divided into design cohort (n = 200) and validation cohort (n = 113) to identify factors associated with the presence and severity of NAFLD and NASH. RESULTS: Factors independently associated with development of NASH included increased levels of alanine aminotransferase (ALT), fasting levels of C-peptide, and ultrasound steatosis scores (USSs), with area under the receiver operating curve (AUROC) values of 0.854 in the design cohort and 0.823 in the validation cohort. NASH activity scores also correlated with level of ALT, USS, and fasting level of C-peptide (R(2) = 0.491). Independent predictors of advanced fibrosis included waist circumference and level of aspartate aminotransferase (AUROC values of 0.839 and 0.846 for design and validation cohorts, respectively; negative predictive values of 98% and 97%, respectively, for a cutoff of -2.14). Previously published scoring systems had significantly lower AUROC values. Levels of CK18 and PNPLA3 polymorphisms correlated with development of NASH but did not add value. CONCLUSIONS: Parameters routinely analyzed in assessing obese patients can be used to determine the presence of NASH and advanced fibrosis. Non-routine tests do not increase diagnostic accuracy. Previously published scores are significantly less accurate.

Identification of mutations in the NUCB2/nesfatin gene in children with severe obesity.

Nesfatin-1 is the N-terminal fragment of nucleobindin-2 (NUCB2) that was identified as a novel satiety molecule in rodents. The protein is reported to exert anorexigenic effects and appears to play an important role in hypothalamic pathways regulating energy homeostasis and food intake. In this study, we hypothesized that mutations in the nesfatin encoding gene NUCB2 might cause obesity in humans. Therefore, we screened the entire coding region of the NUCB2 gene for mutations in a population of 471 obese children and adolescents. Mutation analysis of NUCB2 identified a total of seven sequence variants of which four were previously reported as polymorphisms. The remaining three variants included ex9+6G>C, L125H and K178X and were found in 3 unrelated individuals in the obese population only (0.6%). Biochemical experiments including ELISA and western blot were performed on plasma samples of the obese patient carrying the nonsense mutation K178X. However, neither NUCB2/nesfatin-1 immunoreactive plasma levels of the patient, nor expression of full length NUCB2 differed significantly from matched obese control individuals. In conclusion, we have identified the first genetic variants in the NUCB2 gene in obese individuals, although further functional characterization will be essential to verify disease causality of the mutations.

Transcriptional activation of apolipoprotein CIII expression by glucose may contribute to diabetic dyslipidemia.

OBJECTIVE: Hypertriglyceridemia and fatty liver are common in patients with type 2 diabetes, but the factors connecting alterations in glucose metabolism with plasma and liver lipid metabolism remain unclear. Apolipoprotein CIII (apoCIII), a regulator of hepatic and plasma triglyceride metabolism, is elevated in type 2 diabetes. In this study, we analyzed whether apoCIII is affected by altered glucose metabolism. METHODS AND RESULTS: Liver-specific insulin receptor-deficient mice display lower hepatic apoCIII mRNA levels than controls, suggesting that factors other than insulin regulate apoCIII in vivo. Glucose induces apoCIII transcription in primary rat hepatocytes and immortalized human hepatocytes via a mechanism involving the transcription factors carbohydrate response element-binding protein and hepatocyte nuclear factor-4α. ApoCIII induction by glucose is blunted by treatment with agonists of farnesoid X receptor and peroxisome proliferator-activated receptor-α but not liver X receptor, ie, nuclear receptors controlling triglyceride metabolism. Moreover, in obese humans, plasma apoCIII protein correlates more closely with plasma fasting glucose and glucose excursion after oral glucose load than with insulin. CONCLUSIONS: Glucose induces apoCIII transcription, which may represent a mechanism linking hyperglycemia, hypertriglyceridemia, and cardiovascular disease in type 2 diabetes.

Mechanisms linking obesity with cardiovascular disease.

Obesity increases the risk of cardiovascular disease and premature death. Adipose tissue releases a large number of bioactive mediators that influence not only body weight homeostasis but also insulin resistance - the core feature of type 2 diabetes - as well as alterations in lipids, blood pressure, coagulation, fibrinolysis and inflammation, leading to endothelial dysfunction and atherosclerosis. We are now beginning to understand the underlying mechanisms as well as the ways in which smoking and dyslipidaemia increase, and physical activity attenuates, the adverse effects of obesity on cardiovascular health.

Association between polymorphisms of the Nesfatin gene, NUCB2, and obesity in men.

Nesfatin-1, which originates from its precursor protein nucleobindin-2 (NUCB2), is a novel appetite-regulating molecule that might be associated with the melanocortin signalling pathway in the hypothalamus. The secreted protein appears to play an important role in metabolic control through its anorexigenic and anti-hyperglycemic effects. Therefore, we hypothesized that polymorphisms in the NUCB2 gene might influence the susceptibility for the development of obesity. In this study, we investigated the association of NUCB2 polymorphisms with the development of obesity in an extensive Caucasian population comprising 1049 obese subjects and 315 normal weight control individuals. We selected 8 tagSNPs, which after additional analysis of 6 multi-marker tests, cover most information on common genetic variation in the selected region. We found association with obesity for 3 SNPs (rs1330, rs214101 and rs757081) and 3 multi-marker tests, only when analyzing the male population separately. We subsequently performed linear regression analysis, again in the male population only, and found that several SNPs were associated with BMI, weight and fat free mass. These data indicate that polymorphisms in the NUCB2 gene could play an important role in the protection against the development of obesity in male subjects and might have an influence on energy homeostasis. Nevertheless, further research including replication of our results and elucidation of the molecular mechanism remains necessary.

Association study of MC4R with complex obesity and replication of the rs17782313 association signal.

Recently, genome-wide association studies have discovered several single nucleotide polymorphisms (SNPs) involved in the etiology of complex obesity. A variant downstream from the melanocortin-4 receptor gene (MC4R), a gene known to be involved in monogenic obesity, was reported to be highly associated with BMI. In the present study, we performed a replication study with the previously reported SNP rs17782313. We also included 3 tagSNPs (rs8087522, rs11872992, and rs1943226) for the MC4R gene region in our study to understand the role of this gene in complex obesity. We genotyped all 4 SNPs in a population of 1049 obese cases (mean BMI=38.2±6.2) and 312 healthy lean individuals (mean BMI 22.0±1.7). We could confirm that rs17782313 is highly associated with complex obesity in our population (odds ratio=1.42, 95% CI 1.14-1.77, P=0.002). Furthermore, we found this SNP to be associated with BMI (B=0.92, 95% CI 0.19-1.65, P=0.01) and body weight (B=2.44, 95% CI 0.28-4.60, P=0.03). In addition, we could also detect an association between rs11872992 and complex obesity (odds ratio=0.74, 95% CI 0.57-0.98, P=0.03). Through conditional analysis, we demonstrate that this effect is independent from the rs17782313 association signal. No associations with obesity could be found for rs8087522 and rs1943226. In conclusion, we could replicate the previously reported association between rs17782313 and complex obesity. Furthermore, our data do not support the hypothesis that a SNP in MC4R causes the rs17782313 association signal.

Association study and mutation analysis of adiponectin shows association of variants in APM1 with complex obesity in women.

We performed an association study and mutation analysis of the adiponectin (APM1) gene to study its involvement in the development of obesity. We also studied the interaction with peroxisome proliferator-activated receptor gamma (PPARgamma). 223 obese women and 87 healthy female control subjects were used for association analysis. Mutation analysis was done on 95 morbidly obese adults and 123 overweight and obese children and adolescents. We selected 6 haplotype tagging SNPs in APM1 and the Pro12Ala variant (rs1805192) in PPARgamma to study the interaction. The G allele of rs2241766 was more common in controls (cases 10.8% vs. controls 18.4%, nominal p = 0.011; OR = 0.57, nominal p = 0.018). The rs2241766/rs3774261 haplotype was also associated with obesity (nominal p = 0.004). Only the latter association remained significant after controlling for the False Discovery Rate. Resequencing of exon 2, exon 3 and intron 2 in 95 individuals did not reveal any SNPs in high linkage disequilibrium with rs2241766. No interaction with the Pro12Ala variant in PPARgamma was detected. Mutation analysis of APM1 did not identify mutations. In conclusion, we found an association of an APM1 haplotype with obesity and found that APM1 mutations are not a common cause of monogenic obesity in our cohort.

Association of SIRT1 gene variation with visceral obesity.

The sirtuin SIRT1 is an important regulator of energy metabolism through its impact on glucose and lipid metabolism and therefore we tested the hypothesis that genetic variation in SIRT1 may have an effect on adiposity in a Belgian case/control association study. This study included 1,068 obese patients (BMI > or = 30 kg/m(2)) from the outpatient obesity clinic and 313 lean controls (BMI between 18.5 and 25 kg/m(2)). Anthropometrics were assessed by classical methods and visceral (VFA), subcutaneous (SFA) and total abdominal (TFA) fat areas were determined by a CT scan. The extent of linkage disequilibrium in SIRT1 allowed us to reduce the number of SNPs to two, sufficient to cover the entire gene. The two tagSNPs (rs7069102 and rs3818292) were analyzed by LightSNiP assays in all subjects. Rs3818292 genotypes were similarly distributed in cases and controls, whereas rs7069102 was different for the additive (P = 0.007) and dominant (P = 0.01) model. The variant C-allele of rs7069102 reduced obesity risk with an OR of 0.74 (P = 0.025; 95% CI 0.57-0.96) under a dominant model. In obese male subjects, this variant allele was associated with increased waist circumference (P = 0.04), WHR (P = 0.02), TFA (P = 0.03) and VFA (P = 0.005) (dominant model; adjusted for age and BMI). Rs3818292 was related to VFA (P = 0.005; adjusted for age and BMI) in obese males while in obese women, no significant associations were detected. Our data suggest that genetic variation in SIRT1 increases the risk for obesity, and that SIRT1 genotype correlates with visceral obesity parameters in obese men.

Association of the BDNF Val66Met variation with obesity in women.

Brain-derived neurotrophic factor (BDNF) has been implied in the regulation of food intake. In the present study, we genotyped the Val66Met polymorphism in a Belgian cohort of 532 obese women and 197 healthy female controls and were, for the first time, able to show an association of the 66Met allele with obesity, at least in our female cohort.

Overweight in adolescents: differences per type of education. Does one size fit all?

OBJECTIVE: To assess the lifestyle and prevalence of overweight among 16- to 18-year-old adolescents attending 4 different types of secondary education (SE). DESIGN: Cross-sectional school-based survey. PARTICIPANTS: A community sample of 994 adolescents (body mass index [BMI]: 15-43 kg/m2). VARIABLES MEASURED: Overweight and obesity were assessed by BMI. Health-related quality of life (HRQL) was assessed using the 36-item short-form (SF-36) questionnaire. The Dutch eating behavior questionnaire was administered. Lifestyle was assessed using the Baecke questionnaire and self-reported activities. ANALYSIS: Prevalence of overweight, HRQL and lifestyle were assessed per type of education. Gender differences and differences between BMI-categories were analyzed. RESULTS: Students in Vocational SE were significantly more likely to be overweight (18%) or obese (7.5%) compared to students in other types of SE (chi square-27.0, P < .001). HRQL was significantly lower among obese girls compared to overweight (P = .009) or normal weight girls (P < .01). Obese and overweight adolescents scored higher in restrained eating than their normal weight peers (P < .001) but lower in externally induced eating (P = .001). CONCLUSIONS AND IMPLICATIONS: Lifestyle and prevalence of overweight and obesity seems to differ between different types of education. This could be of importance when making health policy decisions. Health programs should focus on types of education with the highest prevalence of overweight and obesity and should be tailor-made to the specific needs of the targeted type of education.

Predicting type 2 diabetes mellitus: a comparison between the FINDRISC score and the metabolic syndrome.

BACKGROUND: The aim of this study to compare the diagnostic accuracy of the metabolic syndrome (MetS) with the FINDRISC score to screen for type 2 diabetes mellitus T2DM in an overweight/obese population. METHODS: Subjects 18 years or older visiting the obesity clinic of the Antwerp University Hospital were consecutively recruited between 2012 and 2014. Every patient underwent a standard metabolic work-up including a clinical examination with anthropometry. Glucose status was tested using OGTT and Hba1c. FINDRISC questionnaire and MetS were examined. RESULTS: Of 651 subjects, 50.4% were diagnosed with prediabetes, whereas 11.1% was diagnosed with T2DM. FINDRISC score increased with worsening of glucose status 11 ± 3, 13 ± 4 and 15 ± 5 in respectively, subjects without T2DM, prediabetes and T2DM. 312 subjects had the MetS. The aROC of the FINDRISC to identify subjects with T2DM was 0.76 (95% CI 0.72-0.82), sensitivity was 64% and specificity was 63% with 13 as cutoff point. Adding FPG or HbA1c to FINDRISC, the aROC increased significantly to 0.91(95% CI 0.88-0.95) and 0.93(95% CI 0.90-0.97), respectively (p < 0.001). The aROC of the MetS to identify subjects with diabetes was 0.72 (95% CI 0.65-0.78), sensitivity was 75% and specificity was 55%. The aROC of the FINDRISC + HbA1c was significantly higher than the MetS for predicting T2DM (p < 0.001). CONCLUSION: Prediction of type 2 diabetes is important for timely intervention and to avoid chronic complications associated with the disease. Our findings suggest, that it may be of good clinical practice to use the FINDRISC score + HbA1c in a two-step screening model for diabetes rather than using the metabolic syndrome.

Cerebral saturation in cardiac arrest patients measured with near-infrared technology during pre-hospital advanced life support. Results from Copernicus I cohort study.

AIM: To date, monitoring options during pre-hospital advanced life support (ALS) are limited. Regional cerebral saturation (rSO2) may provide more information concerning the brain during ALS. We hypothesized that an increase in rSO2 during ALS in out-of hospital cardiac arrest (OHCA) patients is associated with return of spontaneous circulation (ROSC). METHODS: A prospective, non-randomized multicenter study was conducted in the pre-hospital setting of six hospitals in Belgium. Cerebral saturation was measured during pre-hospital ALS by a medical emergency team in OHCA patients. Cerebral saturation was continuously measured until ALS efforts were terminated or until the patient with sustained ROSC (>20 min) arrived at the emergency department. To take the longitudinal nature of the data into account, a linear mixed model was used. The correlation between the repeated measures of a patient was handled by means of ​a random intercept and a random slope. Our primary analysis tested the association of rSO2 with ROSC. RESULTS: Of the 329 patients 110 (33%) achieved ROSC. First measured rSO2 was 30% ±â€¯18 in the ROSC group and 24% ±â€¯15 in the no-ROSC group (p = .004; mean ±â€¯SD). Higher mean rSO2 values were observed in the ROSC group compared to the no-ROSC group (41% ±â€¯13 versus 33% ±â€¯13 respectively; p < 0.001). The median increase in rSO2, measured from start until two minutes before ROSC, was higher in the ROSC group (ROSC group 17% (IQR 6-29)) than in the no-ROSC group (8% (IQR 2-13); p < 0.001). An increase in rSO2 above 15% was associated with ROSC (OR 4.5; 95%CI 2.747-7.415; p < 0.001). CONCLUSION: Regional cerebral saturation measurements can be used during pre-hospital ALS as an additional marker to predict ROSC. An increase of at least 15% in rSO2 during ALS is associated with a higher probability of ROSC.

Hemostasis and fibrinolysis in non-diabetic overweight and obese men and women. Is there still a role for leptin?

OBJECTIVE: Leptin has been associated with disturbances in hemostasis and fibrinolysis, with inconsistent results on the influence of fat mass. However, the influence of the amount of visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (SAT) has not yet been studied. In this study, we investigated the relationship between leptin and fibrinogen, von Willebrand factor antigen (vWF:Ag), and plasminogen-activator inhibitor-1 (PAI-1) activity and determined the influence of associated metabolic variables and VAT versus SAT. METHODS: Fibrinogen, vWF:Ag, PAI-1,VAT and SAT (CT-scan), and insulin resistance (homeostasis model assessment; HOMA-IR) were measured in 199 women and 81 men with overweight or obesity visiting the weight management clinic of a university hospital. RESULTS: Leptin did not relate to fibrinogen (r = 0.11 and 0.13 in women and men respectively; P > 0.05), a relationship with vWF:Ag was only found in men (r = 0.31; P = 0.005), while leptin related to PAI-1 activity in both men (r = 0.36; P < 0.001) and women (r = 0.23; P < 0.001). Further analysis showed leptin to have an effect on the variation of PAI-1 independent of VAT and HOMA-IR in women, but not in men. Multiple regression showed HOMA-IR to be the most important determinant of PAI-1, both in men and women, but leptin also showed an independent effect. As for vWF:Ag, leptin was an independent determinant in men only. CONCLUSIONS: PAI-1 related to leptin levels independent of fat mass percentage, HOMA-IR, and the amount of VAT and SAT. For vWF:Ag this relationship was found only in men, and not in women, while a relationship with fibrinogen could not be demonstrated.

Is visceral adipose tissue a determinant of von Willebrand factor in overweight and obese premenopausal women?

Visceral obesity has been associated with an increased cardiovascular risk. However, the exact mechanisms are not completely clear. In this study we investigated the relationship between von Willebrand factor (vWF) and visceral adipose tissue (VAT) in a group of 181 overweight and obese premenopausal women visiting the weight management clinic of a university hospital. von Willebrand factor antigen (vWF:Ag), plasminogen activator inhibitor 1 (PAI-1) activity, VAT (computed tomography scan), insulin resistance (homeostasis model assessment of insulin resistance), and other anthropometric and metabolic parameters were measured. Subjects with VAT in the highest quintile had significantly higher levels of vWF:Ag (171+/-60 vs 129+/-40%; P=.001) and PAI-1 (24.7+/-8.5 vs 15.2+/-12.0 AU/mL; P<.001) compared with subjects in the lowest quintile. After correction for fat mass and homeostasis model assessment of insulin resistance the difference was still significant for vWF:Ag (P=.046), but not for PAI-1 (P>.05). Stepwise multiple regression analysis showed VAT and insulin resistance as independent determinants of vWF:Ag, whereas waist circumference, high-density lipoprotein cholesterol, and insulin resistance were independent determinants of PAI-1 activity. In a subgroup of 115 patients, we measured high-sensitivity C-reactive protein and found it to influence the relationship between VAT and vWF:Ag (r=0.16; P=.088), whereas the relationship with PAI-1 was still significant (r=0.21; P=.025). The results from this preliminary study suggest a plausible relation between visceral obesity and endothelial activation, possibly mediated by low-grade inflammation.

Opposite effects of insulin-like molecules and leptin in coronary heart disease of type 2 diabetes Preliminary data.

INTRODUCTION: Leptin and insulin have been reported to be risk factors for coronary heart disease (CHD) in the general population, but their role in type 2 diabetes still remains unclear. MATERIALS AND METHODS: The role of leptin and insulin upon CHD in type 2 diabetes was assessed in 154 patients, aged 31-77 years, who were treated with oral anti-diabetic agents. Multivariate logistic regression analyses were used with CHD (an established history of CHD or an abnormal treadmill test) as dependent, and leptin, insulin and potential confounders as independent variables. RESULTS: Endogenous insulin was significantly associated with CHD in a model controlling for gender, age, duration of diabetes, body mass index, smoking and leptin (Odds ratio 1.45 per decile, 95% confidence interval 1.11-1.90). Improving control for confounding by replacing body mass index by subcutaneous fat (CT-measured at the L4-L5 level) and height in this model, resulted in a significant negative association between leptin and CHD (OR 0.60, 95% CI 0.37-0.96). DISCUSSION: Leptin might have a beneficial effect on CHD in type 2 diabetes, probably by counteracting the effect of insulin-like molecules or insulin resistance. The effect was elucidated only after careful control for confounding by subcutaneous fat, the main source of leptin production.

Resting metabolic rate is an important predictor of serum adiponectin concentrations: potential implications for obesity-related disorders.

BACKGROUND: Little is known about the regulation of adiponectin. Animal studies suggest local regulation by adipocytokines or alterations in energy expenditure, and studies in humans suggest regulation by alcohol intake and ethnicity. OBJECTIVE: To identify regulators of adiponectin in humans, we measured resting metabolic rate (RMR), serum adiponectin, glucose, insulin, triacylglycerol, alcohol intake, and anthropometric indexes in 457 white patients with overweight or obesity. DESIGN: A cross-sectional design was used, and multivariate regression analysis was performed with adiponectin as the dependent variable and potential predictors as independent variables. RESULTS: Simple linear analyses showed significant associations between adiponectin and sex, with a standardized coefficient of -0.38 (women compared with men) and an explanation of variation of the model (R(2)) of 14%; age (0.21; 4%); RMR (-0.52; 27%); fat-free mass (-0.40; 16%); fat mass (-0.16; 2%); visceral fat (-0.24; 6%; computed tomography at L4-L5); fasting triacylglycerol (-0.28; 8%); and insulin resistance (-0.38; 14%; homeostasis model assessment). Adiponectin and alcohol were not associated (-0.04; 0%). Multivariate analyses, which allowed adjustment for confounding, showed that RMR is the most important predictor of adiponectin (-0.31; 29%), followed successively by insulin resistance (-0.16; 31%; model containing RMR and insulin resistance), fat mass (0.20; 34%), age (0.34; 35%), visceral fat (-0.34; 40%), and fasting triacylglycerol (-0.12, 41%). CONCLUSIONS: Low resting metabolism (RMR) is associated with high serum adiponectin. We speculate that subjects with low RMR, who are theoretically at greater risk of obesity-related disorders, are especially protected by adiponectin.