Fibronectin levels in male ejaculate and evidence for its role in unexplained infertility

Vasovasostomy has become a popular and highly successful method of restoring fertility to those who have undergone a vasectomy. However, there is a high correlation between vasostomy and antisperm antibody production leading to spontaneous sperm agglutination and immobilization. There is still considerable disagreement on whether antibodies are the primary causative agent. Our study provides evidence that fibronectin, a ubiquitous glycoprotein whose major function is cell-to-cell adhesion, could be a "subfertility" factor and contribute to male "unexplained infertility." Semen from control, random, and vasovasostomy populations was studied using a sophisticated enzyme-linked immunosorbent assay (ELISA). The results show that fibronectin is significantly present in all groups. The mean concentrations (micrograms/mL) were 753.9 for control, 566.4 for random, followed by significantly higher 1267.3 for the vasovasostomy group (p less than 0.05). The spermatozoa were assayed for bound fibronectin by flow cytometry. The mean percentage of cells bound after background subtract was 29.7 for control and 48.2 for the vasovasostomy group; the difference was significant (p less than 0.05). We conclude that fibronectin is present in semen and bound to sperm cells in great concentrations for individuals having undergone surgical insult and may contribute to male infertility particularly by sperm agglutination.