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Objective To investigate the role played by platelet nitric oxide (NO) metabolism in patients with spontaneous miscarriage (SM) and recurrent spontaneous miscarriage (RSM) compared with healthy pregnant women. Design Retrospective case-control study. Setting Patients and controls in an academic research environment. Intervention(s) None. Patient(s) Thirty singleton pregnant women who experienced SM, nine singleton pregnant women who presented with RSM, and 30 singleton healthy pregnant women matched for age, parity, and gestational age were enrolled. Main Outcome Measure(s) NO levels and peroxynitrite (ONOO - ) production; moreover, inducible NO synthase (iNOS), endothelial NO synthase (eNOS), and nitrotyrosine expression (N-Tyr) were observed in the same samples. Result(s) A significant increase was shown in platelet NO and ONOO - levels and in iNOS and N-Tyr both in SM and in RSM pregnant women compared with controls. Conclusion(s) The data herein reported imply that a modified NO pathway might play a key role in the physiological changes of advancing gestation but may also contribute to the pathophysiology of spontaneous miscarriage. Thus, any factors balancing NO metabolism might be useful in the treatment of miscarriage, thus reducing the substantial morbidity and associated mortality.

Objective To assess the physicochemical characteristics of sperm plasma membrane and to evaluate the immunohistochemical expression of transmembrane and cytoskeletal proteins in spermatozoa isolated from normospermic fertile donors and asthenozoospermic infertile patients. Design Case-control study. Setting Academic male infertility center. Patient(s) Twenty-five infertile patients affected by idiopathic asthenozoospermia and 21 age-matched normospermic fertile donors. Intervention(s) Sperm parameters were evaluated; membrane fluidity and hydration studies, and immunohistochemical analysis were performed in isolated spermatozoa. Main Outcome Measure(s) Semen analyses to ascertain volume, sperm count, motility, and morphology; then membrane fluidity and hydration studies and immunohistochemical analysis were performed on isolated spermatozoa. Result(s) Spermatozoa from the asthenozoospermic group exhibited a reduced fluidity at the lipid-water interface level, an increased fluidity of the deeper portion of the bilayer, and a lower plasma membrane hydration than normospermic cells. Moreover, the immunohistochemical expression of ezrin, Cdc42, CD9, F-actin, and β-tubulin was higher in normospermic samples. Conclusion(s) Our results together assume that a cytoskeletal reorganization induced by a disturbance in the physicochemical features of sperm plasma membrane, and potentially mediated by ezrin, Cdc42, and tetraspanin CD9, could have a role in idiopathic asthenozoospermia.

Objective To characterize the expression pattern of constitutive and inducible nitric oxide synthase (NOS) in spermatozoa isolated from normospermic fertile donors and asthenozoospermic infertile patients, by means of immunohistochemistry. Also to evaluate the immunohistochemical expression of citrulline, a marker of NOS activity, and nitrotyrosine, which indicates the formation of peroxynitrite, which may affect sperm functionality through its cytotoxic action. Design Prospective study. Setting Academic male infertility center. Patient(s) Twenty-nine infertile patients affected by idiopathic asthenozoospermia and 26 age-matched normospermic fertile donors. Intervention(s) Sperm parameters were evaluated, and immunohistochemical analysis was performed in isolated spermatozoa. Main Outcome Measure(s) Semen analyses, to ascertain volume, sperm count, motility, and morphology. Immunohistochemical expression of NOS isoforms, citrulline, and nitrotyrosine. Result(s) Constitutive NOS expression was greater in spermatozoa isolated from normospermic fertile donors. In contrast, the immunohistochemical expression of inducible NOS and nitrotyrosine was higher in asthenozoospermic samples. Our data concerning citrulline indicated enhanced NOS activity in sperm from idiopathic asthenozoospermic patients. Conclusion(s) Our results support the hypothesis that increased NOS activity and an excess of tyrosine nitration may affect the functional characteristics of spermatozoa in idiopathic asthenozoospermia.

Objective To detect peroxynitrite and 3-nitrotyrosine production in human spermatozoa of asthenozoospermic infertile patients and normospermic donors, and evaluate any influence on kinetic sperm features. Design Basic study. Setting Andrology Unit, Dept of Internal Medicine and Biochemistry Institute, Polytechnic University of Marche, Italy. Patient(s) Sixry-nine infertile patients affected by idiopathic asthenozoospermia and 29 normal fertile donors. Intervention(s) No therapeutic intervention was performed on patients. Main Outcome Measure(s) Production of peroxynitrite (ONOO − ) and 3-nitrotyrosine by human spermatozoa; kinetic sperm cells parameters. Result(s) Normospermic fertile donors exhibited ONOO − concentrations significantly lower than those of asthenozoospermic infertile men (9.11 ± 3.37 vs. 27.46 ± 5.77 nmol/10 6 cells); confocal microscopy showed that ONOO − was more evident in spermatozoa of patients than in healthy donors. Moreover, a significant negative correlation was evident between ONOO − concentration and total sperm motility, curvilinear velocity (VCL), straight progressive velocity (VSL), and linearity coefficient. Finally, an increase was found in the nitration of the tyrosine residues in asthenozoospermic samples compared to controls. Conclusion(s) Spontaneous tyrosine nitration occurs in human spermatozoa. This post-translational protein modification is enhanced by an overproduction of peroxynitrite, which is more evident in asthenozoospermic infertile patients when compared with normospermic fertile donors. Motility parameters are negatively affected, suggesting that ONOO − may be involved in defective sperm function.