Expression of anti-Mullerian hormone receptor on the appendix testis in connection with urological disorders

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.

First trimester phthalate exposure and male newborn genital anomalies

BACKGROUND

Anti-androgenic phthalates are environmental chemicals that affect male genital development in rodents leading to genitourinary birth defects. We examined whether first trimester phthalate exposure may exert similar effects in humans leading to an increased incidence of newborn male genital anomalies in a multi-center cohort study.

METHODS

We recruited first trimester pregnant women within The Infant Development and the Environment Study (TIDES) from 2010 to 2012 from four study centers and limited analyses to all mother/male infant dyads who had complete urinary phthalate and birth exam data (N=371). We used multivariate logistic regression to determine the odds of having a genital anomaly in relation to phthalate exposure.

RESULTS

Hydrocele was the primary abnormality observed in the cohort (N=30) followed by undescended testes (N=5) and hypospadias (N=3). We observed a statistically significant 2.5 fold increased risk (95% CI 1.1, 5.9) of having any anomaly and 3.0 fold increased risk (95% CI 1.2, 7.6) of isolated hydrocele in relation to a one log unit increase in the sum of di-ethylhexyl phthalate (DEHP) metabolites.

CONCLUSIONS

First trimester urinary DEHP metabolite concentrations were associated with increased odds of any newborn genital anomaly, and this association was primarily driven by isolated hydrocele which made up the majority of anomalies in newborn males. The association with hydrocele has not been previously reported and suggests that it may be an endpoint affected by prenatal phthalate exposures in the first trimester of development. Future human studies should include hydrocele assessment in order to confirm findings.

Torsion of the Appendix Testis in a Neonate

Torsion of the appendix testis is a rare cause of scrotal swelling in the neonatal period. We present a case of torsion of the appendix testis in a one-day-old male. We discuss the physical examination and radiologic studies used to make the diagnosis. Nonoperative therapy was recommended and the patient has done well. Recognition of this condition in the neonatal period can prevent surgical intervention and its associated risks.

HMGB1 expression and muscle regeneration in idiopathic inflammatory myopathies and degenerative joint diseases

The High-Mobility Group Box 1 protein (HMGB1) is a known nuclear protein which may be released from the nucleus into the cytoplasm and the extracellular space. It is believed that the mobilized HMGB1 plays role in the autoimmune processes as an alarmin, stimulating the immune response. In addition, muscle regeneration and differentiation may also be altered in the inflammatory surroundings. Biopsy specimens derived from patients with idiopathic inflammatory myopathies (IIM) such as polymyositis or dermatomyositis were compared to muscle samples from patients undergoing surgical interventions for coxarthrosis. The biopsy and surgery specimens were used for Western blot analysis, for immunohistochemical detection of HMGB1 in histological preparations and for cell culturing to examine cell proliferation and differentiation. Our data show lower HMGB1 expression, impaired proliferation and slightly altered fusion capacity in the primary cell cultures started from IIM specimens than in cultures of coxarthrotic muscles. The ratio of regenerating muscle fibres with centralised nuclei (myotubes) is lower in the IIM samples than in the coxarthrotic ones but corticosteroid treatment shifts the ratio towards the coxarthrotic value. Our data suggest that the impaired regeneration capacity should also be considered to be behind the muscle weakness in IIM patients. The role of HMGB1 as a pathogenic signal requires further investigation.