High Serum Levels of IL-6 Are Associated with Suicide Attempt but Not with High Lethality Suicide Attempts: A Preliminary Case-Control Study

Suicide attempts are an emerging health problem around the world. Increased levels of IL-6 have been associated with suicidal behavior. Therefore, the aims of this study were to evaluate the serum levels of IL-6 in individuals with suicide attempts and a comparison group and to associate the IL-6 levels with the lethality of the suicide attempt. Additionally, we associated the rs2228145 polymorphism of the IL6R gene with suicide attempts or with the IL-6 serum levels. Suicide attempts and their lethality were evaluated using the Columbia Suicide Severity Rating Scale. The serum concentrations of IL-6 were measured by the ELISA technique in individuals with suicide attempts and then compared to a control group. The rs2228145 polymorphism of the IL6R gene was analyzed by real-time polymerase chain reaction. We found elevated serum levels of IL-6 in the suicide attempt group when compared to the control group (F = 10.37, p = 0.002). However, we found no differences of the IL-6 levels between high and low lethality. The IL6R gene polymorphism rs2479409 was not associated with suicide attempts. Our data suggest that IL-6 serum is increased in individuals with suicide attempts.

The relationship of the carriership of allelic variations in rs2228145 (A > C) of the IL6R gene with the levels of VCAM1 and ICAM1 gene transcripts in patients with essential hypertension

The levels of plasma interleukin 6 and its soluble receptors were found to be elevated in subjects with cardiovascular diseases, which points to amplification of the IL-6-mediated trans-signaling pathway in cells and the development of chronic inflammation. The allelic variation in the rs2228145 IL6R gene is associated with a change in the contents of the soluble and membrane-bound receptor forms mediating the biological activity of IL-6. Cytokine IL-6 is involved in the development of endothelial dysfunction by regulating the expression of the VCAM1 and ICAM1 genes, encoding intercellular adhesion molecules. Prior to this work, no data on the association of essential arterial hypertension (EAH) with rs2228145 allelic variations of the IL6R gene have been reported. The aim of our work was to study the relationship of the carriership of rs2228145 (A > C) allelic variations with the development of EAH and the VCAM1 and ICAM1 transcript levels. We analyzed samples of DNA isolated from the whole blood of 148 healthy donors and 152 patients with EAH (stages I–II). The genotyping was performed by PCR-RFLP. The level of transcripts in peripheral blood leukocytes (PBL) was assessed by real-time PCR. Differences in the frequency distributions of rs2228145 (A > C) genotypes between the control group and the group of patients with EAH (χ2 = 9.303) were found. The frequency of the CC genotype in EAH patients was higher than in healthy people (0.191 and 0.095, respectively). The risk of EAH (I–II stages) development was shown to be 2.3 times higher in CC genotype carriers as compared to individuals with other genotypes (OR = 2.257, 95 % confidence interval 1.100–4.468). The levels of VCAM1 and ICAM1 gene transcripts in PBL of patients with EAH were significantly higher than in healthy people. The level of ICAM1 gene transcripts was almost 4 times higher in patients with CC genotype. The Kruskal–Wallis analysis of variance revealed an effect of rs2228145 (A > C) genotype on the transcriptional activity of ICAM1, which argues for its role in the pathogenesis of endothelial dysfunction and essential hypertension.

IL6R Gene Polymorphic Variant rs2228145(C >A) as a Marker of Genetic Liability to Nonalcoholic Steatohepatitis in the Russian Population of Karelia

Association of IL6R gene polymorphic variant rs2228145(C>A) with the development of nonalcoholic steatohepatitis in Karelia residents is detected. The risk of nonalcoholic steatohepatitis is more than 2-fold higher in carriers of CC genotype by rs2228145 polymorphic marker than in carriers of other genotypes. Plasma levels of IL-6 and the content of IL6R gene transcripts in the peripheral blood leukocytes are higher in patients with nonalcoholic steatohepatitis than in normal subjects. No relationships between rs2228145 polymorphism and the level of IL-6 and content of IL6 and IL6R mRNA were detected. Gene IL6R polymorphic variant rs2228145(C>A) seems to be involved in genetic predisposition of the population of Karelia to nonalcoholic steatohepatitis. However, biochemical and molecular mechanisms underlying the relationship of rs2228145 with the development of nonalcoholic steatohepatitis are not yet studied.