Tissue immunoexpression of IL-6 and IL-18 in aging men with BPH and MetS and their relationship with lipid parameters and gut microbiota-derived short chain fatty acids

Recent studies indicate that inflammation is one of the causes of the development of benign prostatic hyperplasia (BPH). Inflammation may result from past infections, metabolic disorders, but also from the state of functioning of the intestinal microbiota. The aim of the study was to assess whether the diagnostic lipid parameters for metabolic syndrome and short-chain fatty acids (SCFAs) are related to the immunoexpression of interleukins in prostate tissue with benign hyperplasia. The study involved 103 men with BPH, who were divided into two groups depending on the presence of MetS. We analysed tissue immunoexpression of two proinflammatory interleukins: IL-6, which is known to be involved in the development of BPH, and IL-18, which has not been analysed so far. The results of our study indicate that men with BPH + MetS in the stroma of the prostate have a significantly higher overall percentage of IL-6+ cells compared to men without MetS (p = 0.034). The analysis of IL-18 immunoexpression in prostate tissue indicated that in men with BPH + MetS, the glandular part of the prostate had a significantly higher percentage of cells with strong IL-18 expression (p = 0.040). We also noticed a relationship between tissue expression of IL-6 and IL-18 and lipid parameters (TG and HDL). We conclude that lipid disorders occurring in men with BPH increase inflammation in the prostate gland. Moreover, it has also been demonstrated for the first time that, indirectly, through SCFAs, the gut microbiota can act to prevent or create an inflammatory microenvironment in the prostate gland.