Maturation phenotype of Sertoli cells in testicular biopsies of azoospermic men

The involvement of Sertoli cells in different spermatogenic impairments has been studied by an immunohistomorphometric technique using cytokeratin-18 (CK-18) as a marker for immature Sertoli cells, CK-18 is known to be expres sed in Sertoli cells during prenatal and prepubertal differentiation and is normally lost at puberty. Forty-nine azoospermic men were included in the current study. Quantitative measurements on testicular biopsies revealed th e highest CK-18 expression in the mixed atrophy biopsies (22 men), a lower expression in the Sertoli cell-only (SCO) biopsies (12 men), and minimal re sidual staining in the group considered as representing normal spermatogene sis (six obstructive azoospermia patients). The cytokeratin immunopositive- stained tubules were associated either with arrest in spermatogenesis or wi th SCO, Examination of sections from nine men with microdeletions in the AZ F region of the Y chromosome revealed that these men mere either negative f or CK-18 expression or showed only weak residual staining. This may suggest that the spermatogenic defect in the AZF-deteted men originates in the ger m cell and has no impact on Sertoli cell maturation. The cause that determi ned the spermatogenic defect in the other cases of male infertility with hi gh CK-18 expression may have damaged both the Sertoli and the germ cells.