Alu-repeat polymorphism in the tissue plasminogen activator (t-PA) gene, seminal t-PA concentration, and male fertility impairment: A case-control study

Background: Tissue plasminogen activator (tPA) is a protein involved in the fibrinolytic system that catalyzes the conversion of plasminogen into the active plasmin. The activity of tPA is controlled by plasminogen activator inhibitor1. tPA has crucial functions during spermatogenesis. One polymorphism was reported for tPA gene, either the presence of a 300bp Alurepeat (Alu^+) or its absence (Alu^-). Objective: The current work aimed at studying the association between Alu polymorphism in the tPA gene and male infertility. Materials and Methods: Using polymerase chain reaction on genomic DNA isolated from the blood of 79 participants, a region polymorphic for Alu element insertion in t-PA gene was amplified. In addition, total t-PA concentration, plasminogen activator inhibitor1 /t-PA complex concentration, and t-PA activity in seminal plasma were measured by enzymelinked immunosorbent assay. Results: The results indicate that the percentage of infertile participants (n = 50) who were homozygous for t-PA Alu insertion (Alu^+/+), heterozygous Alu^+/- or homozygous for tPA Alu deletion (Alu^-/-) did not change significantly (p = 0.43, 0.81, and 0.85, respectively) when compared with the control participants (n = 29). On the other hand, a significant decrease (p = 0.0001) of t-PA total concentration in seminal plasma was observed in the infertile group in comparison with the control group. However, the results indicate that there is no association between the tPA Alu different genotypes and the total t-PA seminal concentration in the infertile group when compared to the control group (p = 0.63). Conclusion: Data obtained from the current study does not support an association between t-PA Alu polymorphism and tPA seminal concentration or male infertility.