RESUMO
Background: Aldehyde dehydrogenase 2 (ALDH2) is an important enzyme involved in alcohol metabolism. ALDH2 polymorphism has been reported as a risk factor for type 2 diabetes mellitus (T2DM) and is associated with liver insulin resistance due to alcohol consumption in non-diabetic individuals. Herein, we investigated the association between ALDH2 polymorphisms and insulin resistance in patients with T2DM. Methods: We performed a meal tolerance test and the hyperinsulinemic-euglycemic clamp on 71 Japanese participants: 34 patients with T2DM, and 37 non-diabetic participants. We analyzed the ALDH2 polymorphism (ALDH2 rs67); GG type was defined as the T2DM high-risk group, compared with the low-risk AG and AA groups. Results: Glucose levels were similar in the high- and low-risk T2DM groups. The high-risk group for T2DM showed a significantly higher BMI (p < 0.005), insulin resistance in HOMA-IR (p < 0.05), and Insulin sensitivity index (p < 0.05); however, there were no significant differences in insulin resistance in the clamp test (p = 0.10). Alcohol consumption did not differ significantly between groups (p = 0.66). Non-diabetic participants also showed higher HOMA-IR insulin resistance in the high-risk group (p < 0.05), but insulin resistance levels in the glucose clamp tests (p = 0.56) and insulin secretion were not significant. Conclusion: The results suggest that ALDH2 is an important gene associated with insulin resistance and obesity in Japanese patients with type 2 diabetes.
RESUMO
INTRODUCTION: Pancreatic and duodenal homeobox factor-1 (PDX-1) is an imperative gene for insulin secretion in maturity-onset diabetes of the young 4. PDX-1 gene polymorphism was associated with lower first-phase insulin secretion in a genome-wide association study of intravenous glucose tolerance test. It was not associated with type 2 diabetes risk and insulin secretion in a genome-wide oral glucose tolerance test study. However, there have been no reports of overt type 2 diabetes and insulin resistance evaluation using a glucose clamp. We investigated PDX-1 polymorphism, insulin secretion, and insulin resistance in overt type 2 diabetes. RESEARCH DESIGN AND METHODS: We performed a meal tolerance test (MTT) and hyperinsulinemic-euglycemic clamping on 63 Japanese subjects, 30 with type 2 diabetes and 33 non-diabetic. We analyzed the rs1124607 PDX-1 gene polymorphism and defined A/C and C/C as the high-risk group and A/A as the low-risk group. RESULTS: HOMA-beta (homeostatic model assessment beta-cell function) was significantly lower in the high-risk group than in the low-risk group for all subjects (72.9±54.2% vs 107.0±63.5%, p<0.05). Glucose levels and glucose area under the curve (AUC) were not significantly different between both the risk groups. The insulin levels at 60 and 120 min and the insulin AUC after MTT were remarkably lower in the high-risk group than those in the low-risk group for all subjects (AUC 75.7±36.7 vs 112.7±59.5, p<0.05). High-risk subjects with type 2 diabetes had significantly lower insulin levels at 30 and 60 min and insulin AUC than low-risk subjects. Non-diabetic high-risk subjects depicted significantly lower insulin levels at 120 and 180 min. There were negligible differences in insulin resistance between the risk groups. CONCLUSIONS: These results suggest that the PDX-1 genetic polymorphism is crucial for insulin secretion in Japanese patients with type 2 diabetes.
