The relationship between clinical parameters and hepatocyte growth factor/c-Met levels in the sperm of infertile males

Objective: Hepatocyte growth factor is a pleiotropic cytokine with potent mitogenic activity in many organs and tissues. The receptor for hepatocyte growth factor is c-Met, a transmembrane glycoprotein with tyrosine kinase activity. We investigated the relationships between hepatocyte growth factor and c-Met expression levels on sperm motility and male infertility. Methods: The study was designed as a prospective cohort, single-center clinical trial and was conducted between March 2015 and June 2016. The control group consisted of 31 healthy male volunteers with children, while the study group consisted of 61 men who were diagnosed with male infertility after presenting to the In Vitro Fertilization Unit of our Institute. All participants in the study were aged 18–60 years. Sperm samples were taken from each participant and divided in two. The fresh sample was examined immediately for expression of c-Met, while the other was stored frozen and evaluated later for hepatocyte growth factor. Primary outcome measures were the levels of hepatocyte growth factor and c-Met expression, while secondary outcome measures were the correlation of these levels with sperm count, morphology and motility. Results: The c-Met expression level in the control group (26.53 ± 3.50, 19.43–32.73) was significantly lower than in the infertile group (27.95 ± 2.86, 21.58–33.07) (p = 0.039). HGF expression was also significantly lower in the control group (3.25 ± 1.76, 0.83–8.25) than in the infertile group (4.87 ± 4.11, 1.01–21.58) (p = 0.043). In the overall group, c-Met expression showed a positive correlation with sperm motility percentage and a negative correlation with sperm count and sperm morphology percentage. Conclusions: The c-Met receptor and its ligand, hepatocyte growth factor, appear to be fundamental regulators of spermatogenesis, sperm motility and fertilization capacity.