Immunohistochemical characterization of the anti-Müllerian hormone receptor type 2 (AMHR-2) in human testes.
PURPOSE
In males, AMH is secreted by immature Sertoli cells; following exposure to endogenous androgens, Sertoli cells undergo a process of maturation which ultimately inhibits AMH expression to undetectable levels in the serum. However, expression of AMH receptor (AMHR-2) has never been studied in human testes, and high intratubular concentrations of AMH have been reported in recent literature. We therefore assessed expression of AMHR-2 in several testicular tissue samples by immunohistochemistry (IHC).


METHODS
The IHC method was first validated on tissue samples from healthy human testis (n = 2) and from marmoset ovary (n = 1). The same method was then used for assessment on testicular histopathology specimens from patients with mixed atrophy (MA, n = 2), spermatogenetic arrest (SA, n = 2), Sertoli cell-only syndrome (SCO, n = 1), Klinefelter syndrome (KS, n = 1), and nonseminomatous germ cell tumors (NSGCT, n = 1). Tissue samples from two subjects at different pubertal stages (AndroProtect (AP), aged 5 and 14 years) with hematological malignancies were also retrieved.


RESULTS
In adult men, AMHR-2 was expressed on peritubular mesenchymal cells, with patterns closely mirroring α-smooth muscle actin expression. Similar patterns were preserved in almost all conditions; however, in nonseminomatous germ cell tumors the tissue architecture was lost, including AMHR-2 expression. More positive and diffuse staining was observed in tissue samples from prepubertal testes.


CONCLUSIONS
In specimens from both healthy and affected testes, AMHR-2 expression appears weaker in adult than in prepubertal tissue sections. The persistence of AMHR-2 expression seemingly hints at a possible effect of intratesticular AMH on the tubular walls.
['Sansone|A|A|http://orcid.org/0000-0002-1210-2843', 'Isidori|A M|AM|http://orcid.org/0000-0002-9037-5417', 'Kliesch|S|S|http://orcid.org/0000-0002-7561-4870', 'Schlatt|S|S|http://orcid.org/0000-0002-7571-5313']
D000328:Adult D054304:Anti-Mullerian Hormone D006801:Humans D008297:Male D018000:Receptors, Peptide D018125:Receptors, Transforming Growth Factor beta D012708:Sertoli Cells D013737:Testis
AMHR-2 AMH Immunohistochemistry Testis