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Employing purified extracellular matrix (ECM) proteins, i.e. type I, III, IV and V collagens (CI, CHI, CIV, CV), laminin (LM) and fibronectin (FN), as antigen sources we detected autoantibodies to conformational and/or denatured ECM antigens among 34 of 50 sera obtained from Hashimoto's thyroiditis (HT) patients and 6 of 51 control sera obtained from non-autoimmune thyroid disease patients and healthy donors (HT sera vs. control sera p=4×10−9). Reactivity to conformational antigens, mostly due to autoantibodies of the IgG isotype, was observed in 30/50 HT sera and in 6/51 control sera (p=3.5×10−7) and was not always concomitant with that to linear antigens, found in 23/50 HT and in 6/51 control sera (p=1.6×10−4). Ultrastructural analysis of skin biopsies obtained from 18 HT patients without symptomatic cutaneous diseases revealed defects of the stratified squamous epithelium basement membrane in 11/18, alterations of the stroma in 13/18 and both basement membrane and stromal defects in 9/18. Interestingly, 13/13 (p=0.012) and 9/11 (p=0.012) patients with stromal and basement membrane defects respectively, exhibited serum antibodies to at least one ECM antigen involved in the organization of the altered tissue compartment. Lastly, 10/18 skin biopsies presented immunoglobulin (Ig) and/or complement (C3) deposits along the cutaneous basement membrane zone (BMZ) or in the papillary dermis and 9/10 sera from the same patients simultaneously showed antibodies to at least one ECM antigen involved in the organization of these two skin compartments. Besides, 8/11 HT patients with basement membrane defects exhibited Ig or C3 deposits along the BMZ. Our findings suggest that autoantibodies to ECM molecules might contribute to the development of asymptomatic extra-thyroid skin diseases in HT patients.

There are still many controversies about the role of leptin in reproductive function and sexual development. We recently demonstrated that leptin receptors are expressed in rodent Leydig cells and that leptin has inhibitory effects on hCG-stimulated testosterone production by adult rat Leydig cells in culture. In this study, we evaluated the expression of leptin receptor (Ob-R) in rat testes from gestational to adult age in comparison with the pattern of expression of relaxin-like factor (RLF), a specific marker of Leydig cell differentiation status. Immunohistochemical analysis showed that, in prenatal life, Ob-R immunoreactivity was absent at early embryonic ages (E14.5) and appeared at a late embryonic age (E19.5); in postnatal life, immunoreactivity was evident only after sexual maturation (35-, 60-, and 90-days old), whereas it was absent in testes from sexually immature rats (7-, 14-, and 21-days old). Immunoreaction was always confined to Leydig cells and no signal of Ob-R was detected within the tubules. The pattern of expression of Ob-R during testicular development was similar with that of RLF immunoreactivity, which was present in mature fetal as well as adult-type Leydig cells. In contrast with the findings in the testis, in the hypothalamus, the immunohistochemical pattern of Ob-R was very similar between pre- and postpubertal life. Reverse transcription-polymerase chain reaction studies showed that Ob-R expression was present in embryonic, prepubertal, and adult rat testes; semiquantitative analysis showed that mRNA levels were much higher in late versus early embryonic testes, as well as in mature adults versus sexually immature testes, with a gradual increase from younger to older ages. Functional studies showed that, while leptin (150 ng/ml) significantly inhibited hCG-stimulated testosterone production in adult rat Leydig cells (46% reduction; P0.01), it did not modify prepubertal rat Leydig cells steroidogenic function in vitro. In conclusion, we showed that, in rat testis, Ob-R expression is characteristic of mature Leydig cells (fetal and adult type) and it is functional in adult but not prepubertal life.

Androgens are essential in the maintenance of nitric oxide-mediated erectile activity in the rat. The objective of the present study was to investigate the role of androgens in regulating trabecular smooth muscle relaxation in the corpus cavernosum in response to vasoactive challenge in men with erectile dysfunction (ED).Retrospective, double-blind correlation analyses.Fifty-two impotent patients without confounding risk factors for ED were obtained from a total of 250 undergoing diagnostic evaluation.All patients had dynamic colour duplex ultrasound (D-CDU) and hormonal evaluation for LH, total and free testosterone, SHBG and oestradiol.Based upon D-CDU results patients were diagnosed as having arteriogenic (AR, n = 18; mean age 51) or corporeal venocclusive (CVO, n = 13; mean age 49) ED; in other patients (n = 21, mean age 43) a diagnosis of psychogenic (P)-ED was made by comprehensive psychogenic testing and confirmed by normal D-CDU results. AR and CVO patients had altered compliance of cavernous arteries recorded by D-CDU [20-25% lower resistive index (RI) than patients with psychogenic ED], and lower free testosterone (FT) levels than psychogenic patients [42.3 +/-3.5 SE and 49.3+/-5.2 vs. 75.2+/-7.6 pmol/l, respectively; P0.01]. More important, in all patients there was a strong direct correlation between resistive index values and FT levels (r = 0.47, P = 0.002); the relationship was maintained also when adjusted for age, SHBG and oestradiol (r = 0.37, P = 0.02).These results indicate that in men with erectile dysfunction low free testosterone may correlate independently of age with the impaired relaxation of cavernous endothelial and corporeal smooth muscle cells to a vasoactive challenge. These findings give clinical support to the experimental knowledge of the importance of androgens in regulating smooth muscle function in the penis.