Alterations in the human blood-epididymis barrier in obstructive azoospermia and the development of novel epididymal cell lines from infertile men.

Post-testicular sperm maturation requires a specific luminal environment in the epididymis that is created, in part, by the blood-epididymis barrier. There is limited information on gene expression in the epididymis of infertile obstructive azoospermia (OA) patients due to the difficulty in obtaining tissues. The objectives of this study were to determine if epididymal tight junction proteins are altered in OA and to develop cell lines that could serve to elucidate alterations in the epididymis of infertile men. Epididymal claudin (CLDN) 1, CLDN4, and CLDN10 mRNA levels were altered in OA downstream from the obstruction site. Epithelial cell lines derived from the caput epididymidis of one OA patient were developed (infertile human caput epididymal cell line [IHCE]). IHCEs were composed of homogenous populations of diploid cells that ultrastructurally resembled in vivo principal cells. The cells expressed cytokeratin, SPAG11B, CLDN2, CLDN3, desmoplakin, and vimentin. However, the cells did not express several other epididymal markers (CRISP1, SPINLW1, NPC2, CD52, or DCXR) or junctional proteins (CDH1, CDH2, CLDN1, CLDN4, CLDN7, or CLDN8). Further studies using IHCE1 and transepithelial resistance indicated that the cells were unable to form tight junctions. Microarray analyses comparing gene expression in IHCE1 and a recently developed fertile human caput epididymal cell line revealed differential expression of genes encoding junctional proteins, cell junction regulators, and epididymal proteins. Together, these data indicate that epididymal cellular junctions appear to be altered in OA.