IL-6 gene promoter polymorphism [G-174C] and type 2 diabetes in Suez canal area

ABSTRACT

Interleukin-6 [IL-6], a powerful inflammatory mediator, plays a pivotal role in the pathogenesis of insulin resistance and type 2 diabetes. The IL-6 promoter polymorphism, at position -174 [G > C], has been associated to insulin sensitivity although contrasting data have been reported. The aim of this study was to investigate the association of the IL-6 174 G > C promoter polymorphism with risk of T2DM in our populations. PCR restriction fragments length polymorphism [PCR-RFLP] was used to determine the distribution of allele and genotype frequency of this variant. We conducted a case-control study of 52 cases of type 2 diabetes [32 women and 20 men] and 32 control subjects [22 women and 10 men] from out patients diabetic clinic of Suez Canal hospital, age and gender-matched. We evaluated the IL-6 -174 G > C genotype. In control subjects, both C+ [CG + CC genotypes] and G- [GG genotype] carriers. The genotypes of control subjects were 16 [50%, G/G], 6 heterozygous [18.7% G/C] and 10 homozygous [31.3%, C/C]. In diabetic subjects, there were 26 subjects carriers of homozygoits [GG, 50%], 16 heterozygous [C/G, 30.8%] and 10 homozygous [C/C, 19.2%].There was significant difference in fasting blood glucose levels in control carriers of GG genotype compared to GG diabetic subjects' P<0.05, and between control carriers of combining [GC+CC] genotype compared to [GC+CC] diabetic subjects' P<0.05. Also there was significant associations between IL6polymorphisms and the risk of type 2 diabetes in women or men. There were significant associations in lipids profile [serum total cholesterol, s. triglyceride, s. low density lipoprotein and s. high density lipoprotein between control GG genotype compared to GG diabetic subjects' P<0.05, also we found significant difference between control carriers of combining [GC+CC] genotype and [GC+CC] diabetic subjects' P<0.05. Also we found higher non significant biochemical parameters; triglyceride levels, total cholesterol and LDL cholesterol levels in control subjects carrying the G/G genotype comparing to subjects carrying the [GC+CC] genotype In addition, none of the IL6 polymorphisms was significantly associated with the age, sex and body mass index [BMI] in the control and diabetic subjects. In summary, the data in this study support substantial associations between the common polymorphisms in IL6 gene and the risk of type 2 diabetes