Sertoli Cell Number Correlates with Serum Inhibin B in Infant Cryptorchid Boys.

Postnatal maturation of Sertoli cells is crucial for male fertility. The aim of this study was to assess the association between the Sertoli cell number per tubule cross-section (SC/T), the serum level of the Sertoli cell-produced inhibin B, and the A-dark spermatogonia number per tubule (Ad/T) in cryptorchid boys. Forty infant cryptorchid boys aged 4-35 months (median: 13 months) were included in the study. During orchiopexy, blood samples for serum inhibin B, luteinizing hormone (LH), and follicle stimulating hormone (FSH) and testicular biopsies were obtained. Histological sections were evaluated by quantitative immunohistochemical and immunofluorescence analysis including VASA and SOX9 (Sertoli cell marker) in order to measure the tubular germ cell number (G/T), Ad/T, and SC/T. The SC/T correlated negatively with age (p < 0.0002) and positively with G/T, Ad/T, inhibin B, FSH, and LH (all p < 0.01). Inhibin B correlated with LH (p < 0.0001), but not with FSH (p = 0.2077). The SC/T:G/T ratio positively correlated with age (p < 0.0001). Boys with Ad spermatogonia at surgery had a higher number of Sertoli cells compared to boys without Ad spermatogonia. In conclusion, a correlation between Sertoli cell number and inhibin B was proven, indicating that inhibin B possibly reflects the function of Sertoli cells in infant cryptorchid boys.