The Relationship Between The-429T/C And-374T/A Gene Polymorphisms Of The Gene Of Receptor For The Advanced Glycation End-products With Atherosclerosis In Type2Diabetes Patients

Objectives：(1) To study the relationship between the-429T/C and-374T/A genepolymorphisms of the gene of receptor for the advanced glycation end-products(RAGE) with type2diabetes (T2DM).(2) To investigate the relationship between the-429T/C and-374T/A genepolymorphisms of RAGE with atherosclerosis (AS) in T2DM patients.(3) To discuss the relationship between endogenous secretory RAGE (esRAGE)with T2DM atherosclerosis patients.(4) To analysis the relationship between the-429T/C and-374T/A genepolymorphisms of RAGE with esRAGE and inflammatory factors.Subjects and methods：A290T2DM patients conformed to T2DM Diagnostic criteria of world healthorganization (WHO) in1999were enrolled．Meanwhile83healthy unrelated subjectswere recruited as control group (NC)．The-429T/C and-374T/A gene polymorphismsof RAGE gene were detected with polymerase chain reaction--restricted fragmentlength polymorphisms (PCR-RFLP)．The color doppler ultrasound was applied todetermine carotid intima-media thickness (cIMT)．According to cIMT value theT2DM patients were divided into atherosclerosis (AS) group (cIMT≥0.9mm) andno-AS group (cIMT<0.9mm)．Serum levels of endogenous secretory receptor for theadvanced glycation end-products (esRAGE) and inflammation factors includingtumor necrosis α (TNF-α) and interleukin6(IL-6) were measured withELISE．Fasting plasma glucose was measured with peroxide enzymatic method.Hemoglobin A1c (HbA1c) was measured with high performance liquid chromatography．Serum lipid file, hepatic and renal function were measured byenzymatic methods adapted to an autoanalyzer.Descriptive data were expressed as mean±SD. The SPSS13was used for thestatistical analysis．Normally distributed continuous variables were tested withstudent’s t test，while non-normally distributed variables were assessed with theMann-Whitney U test. Normally distributed continuous variables were correlatedusing Pearson Coefficient, while non-normally distributed continuous variables werecorrelated using Spearman’s Coefficient. Chi-square test was calculated to detectfrequency of allele and genotype in different groups. Binary logistic model wascalculated to detect independent associations of the-374and-429genotypes ofRAGE with biochemical indicators, esRAGE, TNF-ɑ and IL-6levels. A stepwisemultivariate linear regression model was performed to discuss independentassociations of biochemical indicators, esRAGE, TNF-ɑ and IL-6levels with cIMT.non-normally distributed date was transformed to normally distributed date withDate-transformed. All results were considered as statistically significant at P<0.05.Results：(1) Compared to NC group, the levels of systolic blood pressure (SBP), diastolicblood pressure (DBP), fasting plasma glucose (FPG）, HbA1c, triglycerides (TG）andlow density lipoprotein cholesterol (LDL-C）were significantly higher in T2DM group(P<0.01)．On the other hand high density lipoprotein cholesterol (HDL-C）level wassignificantly lower (P<0.05)．However，gender, age, smoking, body mass index(BMI）and total cholesterol (CHO）had no statistically significance between twogroups (P>0.05). The cIMT was significantly higher in AS group than that in no-ASgroup in T2DM (1.16±0.41mm vs0.67±0.10mm, P<0.01). BMI and LDL-C levelswere significantly higher in AS group (P<0.05). And gender, age, smoking, durationof diabetes, SBP, DBP, FPG, HbA1c, TG, CHO and HDL-C had no significantdifference.(2) The serum esRAGE levels showed no significant difference between T2DMand NC group（0.2817±0.1588ug/l vs0.2925±0.1178ug/l, P>0.05). But the esRAGE levels were significantly lower in T2DM AS group than that in T2DM no-AS group（0.2712±0.1898ug/l vs0.2974±0.2230ug/l, P=0.035).(3) The serum TNF-α and IL6were separately higher in T2DM group than thatin NC group and T2DM group, that is, TNF-α levels:75.5701±51.9540pg/ml vs33.9261±27.1512pg/ml, P=0.048and IL6levels:10.9737±6.2281pg/ml vs7.4037±3.7211pg/ml，P=0.049． However neither TNF-α levels nor IL6levelsshowed any significant difference between T2DM AS group and T2DM no-AS group.The TNF-α levels nor IL6levels were99.1049±82.6261pg/ml and10.5968±6.9426pg/ml separately in T2DM AS group, and were51.7379±45.1253pg/ml and7.5240±3.2370pg/ml in T2DM no-AS group.(4) Genotypes distribution frequency in all groups were conformedto the Hardy-Weinberg balance．The-429(TC+CC) genotype frequency of RAGEgene in T2DM group was significantly higher than that in NC group（X2=9.056,P=0.003), and C allele was also significantly higher than in T2DM group（X2=8.044，P=0.005）. However，the difference of（TT、TC、CC）and（T、C）genotype frequencybetween T2DM AS group and T2DM no-AS group had no significant difference(X2=8.412，P=0.059).(5) There were no significant difference of-374T/A genotype distributionfrequency among NC group, T2DM group, T2DM no-AS group and T2DM ASgroup.(6) A stepwise multivariate linear regression analysis revealed that cIMT wascorrelated with age, smoking, and SBP, and meanwhile inverse correlation with thecirculating esRAGE level (r=-0.271,P<0.01) and HDL-C level (r=-0.136,P<0.05).And cIMT had no associations with age, gender, smoking, diabetes duration, BMI,HbA1c, FPG, CHO, TG, HDL-C, LDL-C, TNF-ɑ and IL-6levels.(7)The bivariate correlation analysis indicated that the circulating esRAGE levelhad no association with TNF-ɑ and IL-6levels in diabetes patients or in non-diabetessubjects at all.(8) Binary logistic analysis showed the RAGE-429genotype was associated with age (r=0.517,P<0.05）in NC group, but was not correlated with other clinicalparameters, esRAGE, TNF-ɑ and IL6. There was a significant correlation between theRAGE gene-429genotype with BMI and TNF-ɑ (P<0.05) in T2DM group，but wasnot correlated with other clinical parameters, esRAGE and IL6. There was asignificant correlation between the RAGE gene-374genotype with TNF-ɑand IL6inNC group(P<0.05), but was not correlated with other clinical parameters and esRAGElevels. in T2DM group the RAGE gene-374genotype correlated with HbA1c（r=-0.155,P<0.05), but not with other clinical parameters, esRAGE and IL6.Conclusions：(1)There was a significant correlation between-429T/C gene polymorphisms ofRAGE gene with T2DM, C allele was a risk factor for T2DM.(2)Neither-429T/C nor-374T/A gene polymorphisms was associated withT2DM AS in Chinese.(3) There was a significant correlation between-429T/C gene polymorphismswith TNF-ɑ, But not correlated with esRAGE or IL6in T2DM group. There was nocorrelation between-374T/C gene polymorphisms with esRAGE、TNF-ɑ or IL6.(4)The esRAGE and HDL-C might be protective factors for T2DM AS. However,age、smoking、diabetic duration、BMI and LDL-C were risk factors for T2DM AS.(5) T2DM indeed presented a chronic inflammatory disease.