Testicular steroid sulfatase overexpression is associated with Leydig cell dysfunction in primary spermatogenic failure.

BACKGROUND: Decreased testosterone (T) to LH ratio and increased 17ß-estradiol (E2) serum concentrations represent a common finding among patients with severe spermatogenic failure, suggesting a concurrent Leydig cell steroidogenic dysfunction. Aromatase overexpression has been associated with increased serum and intratesticular E2 in these patients. However, it is unknown whether the sulfatase pathway contributes to the increased availability of active estrogens in patients with primary spermatogenic failure. OBJECTIVES: To assess estrogen sulfotransferase (SULT1E1) and steroid sulfatase (STS) mRNA abundance in testicular tissue of patients with Sertoli cell-only syndrome (SCOS) and normal tissues, its association with serum and intratesticular hormone levels, and to explore the mRNA and protein testicular localization of both enzymes. MATERIALS AND METHODS: Testicular tissues of 23 subjects with SCOS (cases) and 22 patients with obstructive azoospermia and normal spermatogenesis (controls) were obtained after biopsy. SULT1E1 and STS transcripts accumulation was quantified by RT-qPCR. For mRNA and protein localization, we performed RT-qPCR in Leydig cell clusters and seminiferous tubules isolated by laser-capture microdissection and immunofluorescence in testicular tissues. Serum and intratesticular hormones were measured by immunoradiometric assays. RESULTS: SULT1E1 mRNA accumulation was similar in both groups. The amount of STS mRNA was higher in cases (p = 0.007) and inversely correlated with T/LH ratio (r = -0.402; p = 0.02). Also, a near significant correlation was observed with intratesticular E2 (r = 0.329, p = 0.057), in agreement with higher intratesticular E2 in cases (p < 0.001). Strong STS immunoreaction was localized in the wall of small blood vessels but not in Leydig cells. Both SULT1E1 and STS mRNA abundance was similar in Leydig cell clusters and the tubular compartment, except for lower SUTL1E1 mRNA in the seminiferous tubules of SCOS patients (p = 0.001). CONCLUSIONS: Our results suggest that an unbalance of the STS/SULT1E1 pathway contributes to the testicular hyperestrogenic microenvironment in patients with primary spermatogenic failure and Leydig cell dysfunction.

Overexpression of CYP19A1 aromatase in Leydig cells is associated with steroidogenic dysfunction in subjects with Sertoli cell-only syndrome.

Several observational studies have showed a combination of lower testosterone (T) to LH ratio and higher estradiol (E2 ) to T ratio in secretory infertile men compared to men with normal spermatogenesis, suggesting a steroidogenic dysfunction of Leydig cells (Lc) that may involve increased aromatase activity. Low T/LH ratio is associated with Lc hyperplasia, which together with LH hyperstimulation may represent compensation for impaired T production. Aromatase expression and oestrogen production are mainly detected in Lc of the testis, although Sertoli and germ cells also contribute to testicular aromatase activity. The aim of this study was to assess the transcriptional expression of CYP19A1 (aromatase) in isolated Lc of subjects with Sertoli cell-only syndrome (SCOS) and signs of Lc impairment. Nineteen patients with SCOS and 10 controls with normal spermatogenesis who had medical indication of testicular biopsy for sperm retrieval were studied. Leydig cells were isolated by Laser Capture Microdissection (LCM) and CYP19A1 mRNA expression was quantified by SYBR® Green-based qPCR. In addition, testicular T and E2 and serum hormonal levels were measured. Relative to control group, CYP19A1 was overexpressed more than twofold in 10/19 cases (2.3-12.2-fold increase), showing a significant increment in cases with low T/LH ratio (T/LH < 2) compared to cases with T/LH ≥ 2 (p = 0.038, REST® ). Moreover, Rq data for CYP19A1 had a direct correlation with testicular levels of E2 and the E2 /T ratio (r = 0.869; p < 0.001 and r = 0.633; p = 0.005). In summary, Lc from infertile patients with signs of Lc dysfunction overexpressed aromatase and showed an increment of testicular E2 . Our results suggest that increased expression of aromatase in Lc leads to higher E2 production and may account for the functional impairment of the Lc in patients with SCOS.

Histological and hormonal testicular function in oligo/azoospermic infertile men.

We characterised and correlated the histological and hormonal aspects of a cohort of 261 azo/oligozoospermic men, applying a quantitative/qualitative evaluation of testicular tissue and serum and intratesticular hormonal measurements. One hundred and 93 azo/oligozoospermic patients were diagnosed as: complete sertoli cell only syndrome (cSCOS), n = 76; focal SCOS, n = 31; maturation arrest, n = 34; hypospermatogenesis, n = 17; mixed atrophy, n = 25; and severe atrophy, n = 10. Normal spermatogenesis was observed in 68 infertile men (controls). Patients with cSCOS, focal SCOS, mixed and severe atrophy had larger LC/clusters (11.5; 11.0; 10.7; 18.9 LC/cluster) than controls (6 LC/cluster; P < 0.001). cSCOS, focal SCOS, mixed and severe atrophy patients had higher FSH, LH and lower T/LH ratio serum levels than the other groups. Intratesticular testosterone concentrations were higher in tissues with complete or focal SCOS (45.6 ng mg(-1) protein) and mixed atrophy (79.0 ng mg(-1) protein) than normal tissues (20.3 ng mg(-1) protein; P = 0.03 and P = 0.007). Considering all subjects, significant correlations were found between T/LH ratio and Leydig cells/cluster (r = 0.510, P < 0.001), FSH levels (r = -0.692, P < 0.001) and with intratesticular testosterone (r = -0.354, P = 0.001); these correlations follow the pattern of severity of spermatogenic damage. By a thorough histological evaluation, we validate the concept that the severity of spermatogenic impairment is associated with major morphological and functional disturbance of the Leydig cell compartment.