Pro12Ala polymorphism in the PPARG gene contributes to the development of diabetic nephropathy in Chinese type 2 diabetic patients.
OBJECTIVE
Oxidative stress is a major contributing factor in the development of diabetic nephropathy. Peroxisome proliferator-activated receptor gamma heterozygous mice and Pro12Ala polymorphism in PPARG exhibited increased resistance to oxidative stress. Smoking increases the production of reactive oxygen species, which accelerates oxidative stress under hyperglycemia. To determine whether the Pro12Ala polymorphism, alone or in combination with smoking, contributes to the development of diabetic nephropathy, a case-control study was performed in 760 Chinese patients with type 2 diabetes.


METHODS
Among patients, 532 had diabetic nephropathy with microalbuminuria (n = 245) or overt albuminuria (n = 287), and 228 did not show either of these symptoms but had had diabetes for > or =10 years and were not undergoing anti-hypertension treatment.


RESULTS
After adjustment for confounders, the Pro/Pro genotype was significantly associated with diabetic nephropathy (odds ratio 2.30 [95% CI 1.18-4.45], P = 0.014); smoking was also an independent risk factor for diabetic nephropathy (1.99 [1.08-3.68], P = 0.029). In addition, we identified possible synergistic effects; i.e., the high-risk group (smokers with the Pro/Pro genotype) showed 4.52 times higher risk (1.78-11.48, P = 0.002) of diabetic nephropathy than the low-risk group (nonsmokers with the Pro/Ala genotype) in a multiple logistic regression analysis controlled for the confounders.


CONCLUSIONS
Our results indicated that the Pro/Pro genotype and smoking were significant independent risk factors for diabetic nephropathy. The possible synergistic effects of genotype and smoking may aggravate oxidative stress and contribute to the development of diabetic nephropathy.
Liu
Limei
L
Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai Diabetes Institute, Shanghai, China. lmliu@sjtu.edu.cn
Zheng
Taishan
T
Wang
Feng
F
Wang
Niansong
N
Song
Yanyan
Y
Li
Ming
M
Li
Lifang
L
Jiang
Jiamei
J
Zhao
Weijing
W
D000368:Aged; D000419:Albuminuria / Q000235:genetics; D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000235:genetics*; D003928:Diabetic Nephropathies / Q000209:etiology* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D011110:Polymorphism, Genetic; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects
D047495:PPAR gamma