The Association Study Of Peroxisome Proliferator Activated Receptorγ2 Gene Pro12 Ala Polymorphism With Type 2 Diabetes Mellitus And Serum Lipids

Introduction and objectiveType 2 diabetes mellitus (T2DM) is a kind of common and complex disease. It is a many genes disease. The two main melodies of incidence are insulin secretion and insulin resistance. Deeb firstly reported that the correlation of Pro 12Ala gene polymorphism and T2DM. He found that mutation rate of A alleles is 9.3% in normal glucose tolerance crowd, decreased glucose-tolerance 4%, but only 2.2% in T2DM. Some scholars have found that Prol2Ala polymorphism has an association with incidence risk of T2DM. A allele may indicate the development of IGT to T2DM. But researches think Pro12Ala polymorphism has no correlation with T2DM in Stefanski, Java Indonesia people and Chinese people.Insulin resistance is the common characteristics of T2DM patients. it can predict the onset of diabetes. The characteristics of insulin resistance of T2DM patients skeletal includes glucose uptake mediated by insulin and use not fully and abated effect of fat oxidation inhibition, and need more insulin to compensate such defect. In many studies, non-diabetes patients with A alleles has stronger insulin sensitivity. There has no significant difference in every stage of insulin secretion between group one with P alleles and group two with A alleles. But the latter has stronger insulin sensitivity. So A alleles may increase insulin sensitivity to decrease the incidence of diabetes.Lipid metabolic disorder is an important risk factor of atherosclerosis. Recent studies show that PPAR gamma plays an important role in regulating lipid metabolism and in the balance of power. PPAR gamma's activation can promote the white adipocyte differentiation and add the amount of small fat cells and reduce the number of big fat cells. Small fat cells have stronger responses to insulin. They promote the uptake of glucose. PPAR gamma can increase insulin and insulin-like growth factor (IGF-1) stimulation of adipocyte differentiation process, add gene expression of some fat tissue specific. PPAR gamma induced gene indication related with fatty acid metabolism in adipose cell division, such as carbonyl coenzyme A, LPL and fatty acid transporters etc. Pro 12Ala mutations decrease activity of LPL and influence the clearance of TG, especially in obese individuals. Probably because obese individuals have more adipose cells and big size, contain many isomers of adipose tissue. So the mutations'influence on serum lipids only occurs in obesity and has high TG and low high-density lipoprotein cholesterol (HDL-C). Many studies suggest that Prol2Ala and fat metabolism disorders are related for non-obesity healthy people. Meirhaeghe reports that people who carry A alleles have high TC and LDL-C. Some studies suggest that who has A alleles have high TC, LDL-C and TG. These results may has association with Prol2Ala mutations. it can lower transcription activity of PPARγ2. Montagnana M think people with A alleles has lower triglycerides. But the domestic research thinks Pro12Ala polymorphism and lipid are unrelated. Recently, Radha V and domestic studies suggest that Pro 12Ala polymorphism and blood lipids are not related and think Pro12Ala mutations'influences on blood lipids have relationship with gender.Pro12Ala PPAR gamma 2 gene polymorphism is currently hotspot. It plays an important role in type 2 diabetes, insulin resistance, lipid metabolism, obesity, and many other diseases. This research investigate the correlation of PPARγ2 gene Prol2Ala polymorphism with type 2 diabetes mellitus and its serum lipids in Liaoning through detecting the expression the normal population of people with type 2 diabetes mellitus to explore the genetic gene detects the expression of Pro 12 Ala PPAR gamma 2 gene polymorphism in normal population and type 2 diabetes patients and influence on lipid metabolism of type 2 diabetes patients to provide effective basis for the treatment of type 2 diabetes.Methods1. Subjects and Grouping(1) Experimental groups①according to WHO 1999 critera,331 type 2 diabetes inpatients were selected (male 178 cases, female 153 cases average age) from the medical ward of Endocrine during august of 2008 to January of 2009.Exclusion standards:a. used mediating lipids medicine. b. alcohol use or smoker. c. coronary heart disease,hypertension cerebrovascular disease,kidney disease,Peripheral blood vessels lesion. d. diabetes mellitus family history and hypertension family history. e. used oral glucose-lowering drugs or insulin(2) Experiments grouping:①331 T2DM patients were divided into Prol2Ala/ Alal2Ala group and Pro 12 Pro group②we divided them into two layers obese group (BMI≥25Kg/m2, n=171cases) and non-obese group (BMI<25Kg/m2, n=160cases) According to body mass index (BMI) and each layer was divided into Pro 12Ala/ Alal2Ala group and Prol2Pro group.③divided 331 T2DM patients into two layers according to sex and each layer was divided into Pro12Ala/Ala12Ala group and Pro12Pro group.(3) Control group:was composed of healthy check-up outpatients(male 136 cases, female 118 cases, without Diabetes Mellitus, hypertension, family history of Diabetes Mellitus or hypertension)2. Detection of each index(1) The genotypes of Prol2Ala variant in PPARy2 gene were determined by polymerase chain reaction-restriction fragment length polymorphisms(PCR-RFLP) assay. The frequencies of PPARy2 Prol2Ala gene type and allele gene were compared among them.(2) Determination of serum total cholesterol, triglyceride and low density lipoprotein, fasting blood sugar were detected by automatic biochemistry analyzer, determination of fasting insulin levels was detected by radioimmunoassay(3) Height weight were measured by specific person and calculated body mass index(BMI)=weight(kg/height(m)2; I calculate insulin resistance index (HOMA-IR) =[FIN(mU/L)×FPG(mmol/L)/22.5] according to HOMA mode.3. Statistical analysisRead sample's gene type and allelic gene rate indirectly. All statistical analysis were performed with Windows SPSS17.0. The quantitative data was presented as mean±SD if there was normally distributed. Genotypic and allelic distributions were compared using the chi-squared test. Hardy-Weinberg equilibrium was computed to the expected genotype distribution. Genotypic and allelic distributions were compared using the chi-squared test. Hardy-Weinberg equilibrium was computed to the expected genotype distribution. The null hypothesis was rejected in each statistical test when P< 0.05.Results1.The frequencies of Pro/Pro, Pro/Ala and Ala/Ala genotype of PPAR72 gene are0.949,0.051 and 0 respectively; The frequencies of Pro allele and Ala allele are 0.974 and 0.026.The frequencies of genotype and allele are not significantly different between people in diabetes and control group(p=0.652). The frequencies of genotype and allele are also not significantly different between people in obese group and non-obese group (P=0.702).2.The number of FPG,HOMA-IR in diabetic group are significantly higher than those in the control group(P<0.05).3.BMI,FPG,FINS,HOMA-IR and HDL-C are not statistically significant between Pro 12Ala/Ala 12Ala group and Pro 12 Pro group in the control group.4. Experiments group(1) The serum lipid levels of TC and LDL-C were higher in Pro12Ala/Ala12Ala group than in Pro12 Pro group (P value was 0.032 and 0.026,respectively) in T2DM.(2) The serum lipid levels of TC,TG and LDL-C were higher in obese patients Pro12Ala/Ala12Ala group than those in with Pro12 Pro group (P value was 0.028,0.025and0.012)(3) The serum lipid levels of TC,TG,LDL-C and HDL-C were is similar between Pro 12Ala/Alal2Ala group and Pro 12 Pro group in male and female respectively. (p> 0.05)Conclusion1. There may be not relation between Pro 12Ala gene polymorphism PPAR gamma 2 and type 2 diabetes in Chinese. But people with Ala allele have lower FPG in control group than people with Pro allele.2.PPARy2 Prol2Ala gene polymorphism may affect serum lipid levels in T2DM and more significant in obese patients (P value was 0.028,0.025and 0.012).3.The influences of PPARy2 Pro 12Ala gene Polymorphism on lipids metabolism were nonsense in statistic between Pro12Ala/Ala12Ala group and Pro12Pro group in male and female.