OBJECTIVE: We studied the significance of BsmI restriction enzyme polymorphism of the vitamin D receptor (VDR) gene and the XbaI and PvuII polymorphisms of the estrogen receptor (ER) gene in patients with type 2 diabetes (n=49), android type obesity with normal carbohydrate metabolism (n=29) and healthy controls (n=138). METHODS: The distribution of genotypes in the study groups, as well as their relationship to fasting and 1 h postprandial serum C-peptide levels were analyzed. RESULTS: Postprandial serum C-peptide levels of BB genotypes were significantly higher in the diabetes and obese groups (6.18+/-5.09 ng/ml) compared with other genotypes (2.71+/-2.45 vs. 1.72+/-1.97 ng/ml, respectively, P=0.05). Among patients with type 2 diabetes and obese subjects, the XX allelic variant of the ER gene was more frequent (P=0.00015). Postprandial C-peptide levels of subjects exhibiting XX genotype were significantly lower compared with those with Xx genotype (1.67+/-2.16 vs. 3.8+/-3.72 ng/ml, P=0.021). The BBXx allelic combination of the VDR/ER receptor genes was less frequent in diabetic patients than in healthy subjects or in obese patients. The BBXx genotype was associated with significantly elevated postprandial C-peptide levels in all subjects compared with other combinations (9.65+/-3.14 vs. 1.35+/-2.82 ng/ml, P=0.003). No difference was found in the distribution of the PvuII polymorphism of the ER gene or in the association with the C-peptide levels among study groups. CONCLUSION: Polymorphisms of the VDR/ER receptor genes might play a role in the pathogenesis of type 2 diabetes by influencing the secretory capacity of beta-cells.
G Speer, K Cseh, G Winkler, P Vargha, E Braun, I Takacs and P Lakatos
G Winkler, S Kiss, L Keszthelyi, Z Sapi, I Ory, F Salamon, M Kovacs, P Vargha, O Szekeres, G Speer, I Karadi, M Sikter, E Kaszas, O Dworak, G Gero and K Cseh
OBJECTIVE: The aim of the study was to evaluate the expression of tumor necrosis factor (TNF)-alpha protein in the subcutaneous and visceral adipose tIssue in correlation with adipocyte cell Volume, serum TNF-alpha, soluble TNF-receptor-2 (sTNFR-2) and indirect parameters of insulin resistance in overweight/obese and lean healthy persons. DESIGN: A cross-sectional case-control study was used. PATIENTS: Twenty-eight overweight/obese probands with normal glucose tolerance (BMI>27 kg/m(2)) and 15 lean people (BMI<25 kg/m(2)), all of them undergoing planned surgical operation, participated in the study. METHODS: Two to four grams of subcutaneous and visceral adipose tIssue were removed and studied using semi-quantitative immunohistochemical staining of the TNF-alpha protein. Serum TNF-alpha, sTNFR-2 (ELISA) and fasting C-peptide (RIA) were measured. RESULTS: TNF-alpha protein was expressed in adipocytes of both depots. The expression was evaluated visually and found to be greater in the obese patients. Significantly higher serum TNF-alpha (5.58+/-0.87 pg/ml vs 4.21+/-0.55, mean+/-s.d., P<0.01, Mann-Whitney) and sTNFR-2 levels (7.84+/-3.56 ng/ml vs 4.59+/-1.35, P=0.005) were found in the obese subgroup in correlation with the fasting C-peptide level (r=0.49, P=0.003; and r=0.74, P=0.001) and the C-peptide/ blood glucose ratio (r=0.47, Spearman, P=0.005; and r=0.70, P=0.001). The cell Volume of both adipocyte depots was found to have a significant positive correlation with serum TNF-alpha and sTNFR-2 levels in the total group of patients (subcutaneous: r=0.52, P=0.0003; r=0.69, P<0.0001; visceral: r=0.65, P<0.0001; r=0.63, P<0.0001) and in both subgroups. CONCLUSIONS: Adipocyte cell Volume of both the subcutaneous and visceral fat depots may be determinants of TNF-alpha, sTNFR-2 production and obesity-linked insulin resistance.