VENDRELL, JOAN, MONTSERRAT BROCH, NURIA VILARRASA, ANA MOLINA, JOSE MANUEL GÓ MEZ, CRISTINA GUTIÉ RREZ, IMMACULADA SIMÓ N, JOAN SOLER, AND CRISTÓ BAL RICHART. Resistin, adiponectin, ghrelin, leptin, and proinflammatory cytokines: relationships in obesity. Obes Res. 2004;12:962-971. Objective: To evaluate interactions among leptin, adiponectin, resistin, ghrelin, and proinflammatory cytokines [tumor necrosis factor receptors (TNFRs), interleukin-6 (IL-6)] in nonmorbid and morbid obesity. Research Methods and Procedures: We measured these hormones by immunoenzyme or radiometric assays in 117 nonmorbid and 57 morbidly obese patients, and in a subgroup of 34 morbidly obese patients before and 6 months after gastric bypass surgery. Insulin resistance by homeostasis model assessment, lipid profile, and anthropometrical measurements were also performed in all patients. Results: Average plasma lipids in morbidly obese patients were elevated. IL-6, leptin, adiponectin, and resistin were increased and ghrelin was decreased in morbidly obese compared with nonmorbidly obese subjects. After adjusting for age, gender, and BMI in nonmorbidly obese, adiponectin was positively associated with HDLc and gender and negatively with weight (␤ ϭ Ϫ0.38, p Ͻ 0.001). Leptin and resistin correlated positively with soluble tumor necrosis factor receptor (sTNFR) 1 (␤ ϭ 0.24, p ϭ 0.01 and ␤ ϭ 0.28, p ϭ 0.007). In the morbidly obese patients, resistin and ghrelin were positively associated with sTNFR2 (␤ ϭ 0.39, p ϭ 0.008 and ␤ ϭ 0.39, p ϭ 0.01). In the surgically treated morbidly obese group, body weight decreased significantly and was best predicted by resistin concentrations before surgery (␤ ϭ 0.45, p ϭ 0.024). Plasma lipids, insulin resistance, leptin, sTNFR1, and IL-6 decreased and adiponectin and ghrelin increased significantly. Insulin resistance improved after weight loss and correlated with high adiponectin levels. Discussion: TNF␣ receptors were involved in the regulatory endocrine system of body adiposity independently of leptin and resistin axis in nonmorbidly obese patients. Our results suggest coordinated roles of adiponectin, resistin, and ghrelin in the modulation of the obesity proinflammatory environment and that resistin levels before surgery treatment are predictive of the extent of weight loss after bypass surgery.

Polymorphism at the ADH2 and ADH3 loci of alcohol dehydrogenase (ADH) has been shown to have an effect on the predisposition to alcoholism in Asian individuals. However, the results are not conclusive for white individuals. We have analyzed the ADH genotype of 876 white individuals from Spain (n ‫؍‬ 251), France (n ‫؍‬ 160), Germany (n ‫؍‬ 184), Sweden (n ‫؍‬ 88), and Poland (n ‫؍‬ 193). Peripheral blood samples from healthy controls and groups of patients with viral cirrhosis and alcohol-induced cirrhosis, as well as alcoholics with no liver disease, were collected on filter paper. Genotyping of the ADH2 and ADH3 loci was performed using polymerase chain reactionrestriction fragment length polymorphism methods on white cell DNA. In healthy controls, ADH2*2 frequencies ranged from 0% (France) to 5.4% (Spain), whereas ADH3*1 frequencies ranged from 47.6% (Germany) to 62.5% (Sweden). Statistically significant differences were not found, however, between controls from different countries, nor between patients with alcoholism and/or liver disease. When all individuals were grouped in nonalcoholics (n ‫؍‬ 451) and alcoholics (n ‫؍‬ 425), ADH2*2 frequency was higher in nonalcoholics (3.8%) than in alcoholics (1.3%) (P ‫؍‬ .0016), whereas the ADH3 alleles did not show differences. Linkage disequilibrium was found between ADH2 and ADH3, resulting in an association of the alleles ADH2*2 and ADH3*1, both coding for the most active enzymatic forms. In conclusion, the ADH2*2 allele decreases the risk for alcoholism, whereas the ADH2*2 and ADH3*1 alleles are found to be associated in the European population. (HEPATOLOGY 2000;31:984-989.)Ingested alcohol is mostly metabolized in the liver by the successive action of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Both enzymes exhibit genetic polymorphisms that influence the rate of conversion of ethanol to acetaldehyde, and of acetaldehyde to acetate. It has been consistently reported that ALDH2 is the most important alcohol-metabolizing gene affecting predisposition to alcoholism in Asian populations. The prevalence of the ALDH2*2 allele, which codes for a physiologically inactive mitochondrial ALDH form, is lower in alcoholics than in nonalcoholics. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] However, this allele has not been found in white individuals. 21 Regarding ADH, polymorphism is detected at the ADH2 and ADH3 loci. Alleles of ADH2 found in whites and Asians are ADH2*1 and ADH2*2, which encode for the low activity (␤1) and high activity (␤2) subunits, respectively. The kcat values for the resulting dimeric isozymes are very different: 9.2 min Ϫ1 for ␤1␤1 and 400 min Ϫ1 for ␤2␤2. 22 The ADH2*2 frequency is much higher in Asians (60%-80%) than in whites (0%-10%). 21 ADH3 alleles are ADH3*1 and ADH3*2, which produce the ␥1 and ␥2 subunits. The ␥1␥1 isozyme (kcat ϭ 87 min Ϫ1 ) is moderately more active than the ␥2␥2 isozyme (kcat ϭ 35 min Ϫ1 ). 22 ADH3*1 frequency is about 50% to 60% in whites and higher than 90% in Asians. 3,23 ...

Recent studies have shown that the tumor necrosis factor (TNF) system is implicated in the insulin resistance of human obesity. Plasma concentrations of the soluble fraction of the TNF receptors 1 and 2 (sTNFR1 and sTNFR2) are thought to reflect the degree of activation of the TNF system. The purpose of this study was to explore whether this activation, as measured by the levels of circulating sTNFR1 and sTNFR2, is associated with insulin resistance. A total of 19 men (mean age 36.2 +/- 1.9; BMI 28.8 +/- 1.2, range 22.2-35.7) and 17 premenopausal women (age 34.9 +/- 1.4; BMI 28.1 +/- 0.8, range 19-37.9) were studied. Men showed higher levels of plasma sTNFR1 and sTNFR2 than women. However, obese men showed increased levels of sTNFR2 but similar levels of sTNFR1 in comparison with obese women. In fact, sTNFR2 levels correlated with BMI (r = 0.50, P = 0.002), fat-free mass (FFM) (r = 0.61, P < 0.0001), and waist-to-hip ratio (WHR) (r = 0.39, P = 0.02), but not with fat mass or percent fat mass. sTNFR2 levels correlated with basal glucose levels (r = 0.45, P = 0.007), area under the curve (AUC) for glucose during an oral glucose tolerance test (r = 0.42, P = 0.013), and with the quotient AUC glucose/log AUC insulin (r = 0.41, P = 0.015). sTNFR2 also correlated negatively with insulin sensitivity (S(I)), evaluated using the frequently sampled intravenous glucose tolerance test with minimal model analysis (r = -0.38, P = 0.02). Plasma sTNFR1 levels were not associated with any of these variables. Because WHR influenced both S(I) and sTNFR2 levels, we constructed a multiple linear regression to predict S(I), with WHR and sTNFR2 as independent variables. In this model, both WHR (P = 0.0078) and sTNFR2 levels (P = 0.025) contributed to 47% of the variance in S(I). In parallel with higher FFM, lean and obese men showed a lower S(I) (2.9 +/- 0.9 vs. 5.2 +/- 1.3 min(-1) x mU x l(-1), P = 0.001; and 1.15 +/- 1.1 vs. 1.8 +/- 0.8 min(-1) x mU x l(-1), P = 0.035, respectively) and higher sTNFR2 levels in comparison with lean and obese women, respectively. After controlling for FFM, the correlation between S(I) and sTNFR2 levels disappeared, indicating that FFM was significantly influencing these associations. In summary, plasma sTNFR2 levels, but not sTNFR1, were proportional to BMI, WHR, FFM (a well-known confounder in the evaluation of insulin sensitivity), basal and postload glucose levels, and insulin resistance. These findings support TNF-alpha as a system regulating insulin action in human obesity.

Type 2 diabetes and the insulin resistance syndrome have been hypothesized to constitute manifestations of an ongoing acute-phase response. We aimed to study an interleukin-6 (IL-6) gene polymorphism in relation to insulin sensitivity (I L-6 is the main cytokine involved in an acute-phase response). Subjects homozygous for the C allele at position -174 of the IL-6 gene (SfaNI genotype), associated to lower plasma IL-6 levels, showed significantly lower integrated area under the curve of serum glucose concentrations (AUC glucose ) after an oral glucose tolerance test, lower blood glycosylated hemoglobin, lower fasting insulin levels, lower total and differential white blood cell count (a putative marker of peripheral IL-6 action), and an increased insulin sensitivity index than carriers of the G allele, despite similar age and body composition. A gene dosage effect was especially remarkable for AUC g l u c o s e (6.4 vs. 9.3 vs. 9 . 7 mmol/l in C/C, C/G, and G/G individuals, respectively). The serum concentration of fully glycosylated cortisol binding globulin (another marker of IL-6 action), suggested by concanavalin A adsorption, was lower in C/C subjects than in G/G individuals (32.6 ± 2.9 vs. 37.6 ± 4.6 mg/l, P = 0.03). In summary, a polymorphism of the I L-6 gene influences the relationship among insulin sensitivity, postload glucose levels, and peripheral white blood cell count. Diabetes 49:517-520, 2000 I t has been hypothesized that type 2 diabetes and the insulin resistance syndrome are partly a manifestation of an ongoing acute-phase response (1,2). This hypothesis is based on the findings of increased blood concentrations of markers of the acute-phase response, including C-reactive protein, serum amyloid-A, -1 acid glycoprotein, sialic acid, and cortisol (1-4).Interleukin (IL)-6 is a pleiotropic cytokine involved in the regulation of the acute-phase reaction, immune responses, and hematopoiesis. Plasma IL-6 levels are elevated in type 2 diabetic patients, particularly in those with features of the insulin resistance syndrome (1,2). Although the concentrations of multiple components of the acute-phase response increase together, not all of them increase uniformly in all patients. These variations indicate that the components of the acute-phase response are individually regulated, and this may be explained in part by differences in the pattern of production of specific cytokines (5). Recently, it has been reported that a polymorphism in the 5 flanking region of the I L-6 gene alters the transcriptional response to stimuli such as endotoxin and IL-1 (6).In addition to its role in acute-phase response, IL-6 has been recently shown to be released by adipose tissue, and this release is greater in obese subjects, especially in those with a higher waist-to-hip ratio (7). Furthermore, IL-6 increases p o s t p r a n d i a l l y, in parallel to glucose and insulin levels, in the interstitial fluid of subcutaneous adipose tissue (8). This increase suggests that IL-6 might modulate adipose glucose metabolism in the...