Study On The Relationship Between The Gene Polymorphisms Of Type 2 Receptor Of Bradykinin And Type 2 Diabetes Mellitus And Complicated Hypertension

Objectives: This study was to investigate the distribution of the gene polymorphism in promoter -58T/C and exon2 181C/T of type 2 receptor of bradykinin (BKB₂R) in the Han population in Tianjin, and to assess the relation between -58T/C or 181C/T polymorphism of the gene and type 2 diabetes mellitus(T2DM) and complicated hypertension.Methods: A total of 448 Han people was involved in the study. The participants included of 125 control subjects(60 male, 65 female, average age was 57.77 ± 6.38) as group A, 180 T2DM patients with normal blood pressure (94 male, 86 female, average age was 57.27 + 5.74) as group B, 143 T2DM patients with stage 1 or 2 hypertension (67 male, 76 female, average age was 58.41 +6.93) as group C. T2DM patients were recruited among in-patients in our hospital during the period of time between May 2002 and October 2004. People who underwent a check-up examination in our hospital during the period of time between October 2003 and January 2004 were enrolled as random population control. The participants were genetically unrelated and were all living in Tianjin. Genomic DNA was extracted from the collected blood samples. The -58T/C polymorphism was determined by polymerase chain reaction-single strain conformation polymorphism (PCR-SSCP) analysis. The 181C/T polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The polymorphic gene found by SSCP or RFLP technique was cloned and sequenced. Lastly we analyze the clinical data.Results: (1) The mutation of 181C→ T of BKB2R was not found in eachgroup. (2) The frequency of the allele -58C of B2R in the controlled group was 46.0%, which was lower than that in South German population, in African-Americans, or in Canadian population (all P<0.01), and was similar with that in Japanese population or the Han people in Peking (both P>0.05). (3) The genotype frequency of -58T/C polymorphism of the B2R gene in group A was 16.8% for CC, 58.4% for CT, and 24.8% for TT. It was respectively 16.1%, 57.8% and 26.1% in group B, 19.6%, 57.3% and 23.1% in group C, and was 17.6%, 57.6% and 24.8% in group B+C. The statistics showed that there was no significant difference of the genotype frequency among A, B, C groups or between A and B+C groups (both P>0.05). (4) Analysis showed that there were significant differences in diastolic blood pressure (DBP) among the patients with CC, CT and TT genotypes in B, C, or B+C group (all PO.01), among which the patients with CC genotype seemed to have higher DBP than that with CT (P<0.01) and TT genotype (PO.05). Between CT and TT genotype, DBP was similar. There were no significant differences in systolic blood pressure (SBP) among the patients with CC, CT and TT genotypes in B, C, or B+C group (all P>0.05). (5) The prevalence rate of incipient diabetic nephropathy in the patients with CC genotype was significant higher than that with CT (P<0.01) or TT genotype (P<0.05) in group C, but there was no significant differences among three genotypes in group B or in group B+C (both P>0.05).Conclusions: The data showed that there was -58T/C polymorphism of BKB2R gene in the Han population of Tianjin. But there was no 181C/T polymorphism in the same population. The study indicated that the -58T/C polymorphism was not associated with T2DM, but it was associated with DBP levels in T2DM. The patients with CC genotype had higher DBP. The -58T/C...