The decline of fertility in male uremic patients is correlated with low expression of the cystic fibrosis transmembrane conductance regulator protein (CFTR) in human sperm

BACKGROUND: The present study was designed to investigate the possible association between infertility of male uremic patients and expression of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in their sperm. METHODS: Semen was collected and analyzed. Serum levels of FSH, LH and testosterone were measured by radioimmunoassay. The sperm CFTR expressions of 21 uremic patients and 15 renal transplant patients were measured and compared with those of 32 healthy and 33 infertile men. RESULTS: Only 9 +/- 5.9% of sperm from uremic patients expressed CFTR, significantly less than those of the renal transplant patients (29 +/- 14.3%, P < 0.001), the infertile men (42 +/- 20.7%, P < 0.001) and the healthy men (51 +/- 20.5%, P < 0.001). Furthermore, significantly fewer sperm from renal transplant patients expressed CFTR than those of the infertile men (P < 0.05) and the healthy men (P < 0.01). LH levels in uremic patients were significantly higher than in all other groups, whereas FSH levels in uremic patients were only significantly higher than in infertile and healthy men. There was no significant difference in testosterone level among the four categories. CONCLUSIONS: Sperm CFTR expression is depressed in uremic patients but recovers to some degree after renal transplant along with some improvement in fertility, indicating a 'reversible' change. These results suggest that the CFTR expression rate in sperm is correlated with the decline of uremic patients' fertility, and may be considered as a potential marker to assess the fertility of male uremic patients.