Objective: To investigate the number, location, and secretory products of macrophages in human testes showing normal and abnormal spermatogenesis.
Design: Evaluation of testicular biopsies with the use of immunohistochemistry, laser capture microdissection, and reverse transcriptase polymerase chain reaction.
Setting: University research and clinical institutes.
Patient(s): Infertile men with germ cell arrest (n = 10), Sertoli cell only (n = 8), or mixed atrophy (n = 7) syndromes, and with cases of idiopathic infertility showing normal spermatogenesis (n = 8).
Intervention(s): Diagnostic testicular biopsy was performed on participants.
Main outcome measure(s): We recorded the location, number, distribution, and cytokine expression of human testicular macrophages.
Result(s): CD68-positive macrophages were found in the testes of all groups analyzed. These macrophages expressed the genes for interleukin 1 and tumor necrosis factor-alpha, and were located in the interstitium, tubular wall, and tubular lumen. In Sertoli cell only and germ cell arrest syndromes, the overall macrophage number was increased over twofold. In all pathologic states, there was a significant shift of these cells from the interstitium to the tubules.
Conclusion(s): Our study suggests that increased numbers of CD68-positive macrophages directly (via phagocytosis) or indirectly (via paracrine actions exerted through their secretory products) are involved in the regulation of steroidogenesis, Sertoli cell activity, germ cell survival, and, in consequence, in the pathogenesis or maintenance of infertility states in the human testes.