Investigation of relationship between IL-6 gene variants and hypertension in Turkish population

Abstract

Hypertension (HT) is a common and life threating health problem worldwide leading to stroke, heart attack and renal failure. It is characterized by elevated blood pressure forced heart load. Human interleukin-6 (IL-6) and C- reactive protein (CRP) are known to be involved in inflammatory processes. IL-6 gene is a polymorphic gene which -174 G/C is a common and -572 G/C is a rare polymorphisms identified in promoter region. Publications on IL-6 gene polymorphisms raised the question whether this gene polymorphisms lead to susceptibility to HT or not. To investigate the effects of IL-6 gene -174 G/C (rs 1800795) and -572 G/C (rs1800796) polymorphisms on plasma IL-6 and CRP levels and their associations with hypertension disease in Turkish population we analyzed -174 G/C and -572 G/C polymorphisms and plasma IL-6 and CRP levels in 111 healthy controls and 108 hypertension patients from Adıyaman, Turkey. We determined the genotypes using polymerase chain reaction-restriction fragment length polymorphism and analyzed plasma levels of IL-6 by ELISA and CRP by automated standard biochemical methods. We have found no statistically significant differences between IL-6 gene -174 G/C and -572 G/C genotypes and allelic frequencies and IL-6 and CRP plasma levels and HT (p > 0.05). No CC genotype was found in control subjects for -572 G/C polymorphism. In conclusion, we found relation to -174 G/C and -572 G/C gene variants between neither IL-6 and CRP levels nor hypertension. The -572 G allele and GG genotype are predominant in Turkish population in Adıyaman, Turkey whereas the CC genotype is very rare.

Keywords: CRP; Hypertension; IL-6 gene polymorphism; −174 G/C, −572 G/C gene variants.