Are oxidative stress markers associated with unexplained male infertility?

Male infertility can be responsible for up to 20% of the cases attending fertility consultation facilities; nonetheless, the underlying molecular mechanisms that could explain it are still elusive. Therefore, we aimed to evaluate conventional and functional parameters of semen samples from patients who presented with male infertility of unknown origin. Conventional semen parameters and functional parameters (i.e. intracellular reactive oxygen species production, mitochondrial membrane potential, sperm chromatin structure assay, sperm membrane lipid peroxidation and antioxidant capacity of seminal plasma) were evaluated on semen samples from 54 healthy donors, 23 patients with idiopathic infertility and 34 fertile controls. No significant differences were observed in the conventional seminal parameters between the fertile and infertile men. However, increased intracellular reactive oxygen species (ROS) production and DNA fragmentation were observed in the infertile patients compared to the fertile group. Alterations in intracellular ROS production and DNA fragmentation could be associated with male idiopathic infertility. These parameters could eventually distinguish both groups more accurately than the conventional parameters. Our current results are encouraging, and the efficacy of these parameters in the clinical settings needs to be further assessed to establish their predictive potential as a marker of unexplained male infertility.

[Evaluation of the role of the monosaccharides, mannose and N-acetylglucosamine in the induction of the acrosome reaction in human spermatozoa]. / Evaluación de la reacción acrosomal en espermatozoides humanos inducida por los monosacáridos manosa y N-acetilglucosamina.

OBJECTIVE: The aim of this investigation was to evaluate the role of the monosaccharides, mannose and N-acetylglucosamine in the induction of the acrosome reaction in human spermatozoa. METHODS: Each individual gave a semen sample, the samples were capacitated using bovien serum albumin; the analysis of the mannose and N-acetylglucosamine induced acrosome reaction was evaluated for fluorescence microscopy and flow cytometry. RESULTS: The results obtained in the acrosomal reaction in the 10 samples evaluated by flow cytometry showed that only calcium ionophore A23187 induced acrosomal reaction (p < 0.001); in contrast, by fluorescence microscopy, was observed a statistically significant increase in the induced acrosomal reaction with mannose and N-acetylglucosamine (p < 0.001). CONCLUSIONS: The monosaccharides mannose and N-acetylglucosamine induces partial acrosomal reaction and it does not complete, therefore the spermatozoa due to partial acrosomal reaction and the morphologics modifications that suffer during that process is able to fertilize the oocyte.

Evaluación de la reacción acrosomal en espermatozoides humanos inducida por los monosacáridos manosa y N-acetilglucosamina / Evaluation of the role of the monosaccharides, mannose and N-acetylglucosamine in the induction of the acrosome reaction in human spermatozoa

Objetivo: El objetivo de esta investigación fue evaluar el papel de los monosacáridos, manosa y Nacetilglucosamina en la inducción de la reacción acrosomal en espermatozoides humanos. Método: Cada individuo donó una muestra de semen, la cual fue sometida al proceso de capacitación usando albúmina sérica bovina, posterior a lo cual se evaluó el porcentaje de espermatozoides que presentaban reacción acrosomal al estimularlos con manosa y N-acetilglucosamina, usando microscopía de fluorescencia y citometría de flujo. Resultados: Los resultados obtenidos en las 10 muestras evaluadas mediante citometría de flujo mostraron que sólo el ionóforo de calcio A23187 indujo reacción acrosomal (p<0,001); en contraste por microscopía de fluorescencia usando la lectina PSA-FITC, se observó un aumento estadísticamente significativo en la reacción acrosomal inducida con manosa y N-acetilglucosamina (p<0,001). Conclusiones: Los monosacáridos manosa y N-acetilglucosamina inducen reacción acrosomal parcial y no completa, por lo tanto el espermatozoide gracias a la reacción acrosomal parcial y a las modificaciones morfológicas que sufre durante ese proceso es capaz de fertilizar el oocito (AU)

Objective: The aim of this investigation was to evaluate the role of the monosaccharides, mannose and N-acetylglucosamine in the induction of the acrosome reaction in human spermatozoa. Methods: Each individual gave a semen sample, the samples were capacitated using bovien serum albumin the analysis of the mannose and N-acetylglucosamine induced acrosome reaction was evaluated for fluorescence microscopy and flow cytometry. Results: The results obtained in the acrosomal reaction in the 10 samples evaluated by flow cytometry showed that only calcium ionophore A23187 induced acrosomal reaction (p<0.001); in contrast, by fluorescence microscopy, was observed a statistically significant increase in the induced acrosomal reaction with mannose and N-acetylglucosamine (p<0.001). Conclusions: The monosaccharides mannose and N-acetylglucosamine induces partial acrosomal reaction and it does not complete, therefore the spermatozoa due to partial acrosomal reaction and the morphologics modifications that suffer during that process is able to fertilize the oocyte (AU)

The production of MLR-blocking factors after lymphocyte immunotherapy for RSA does not predict the outcome of pregnancy.

PROBLEM: The questions of whether production of mixed lymphocyte reaction-blocking factors (MLR-BFs) after immunotherapy with lymphocytes for recurrent spontaneous abortion (RSA) has prognostic value and whether cytotoxic antibodies are also involved were tested. METHOD OF STUDY: A prospective study with 33 patients who had a history of two or more abortions, lacking MLR-BFs, was carried out. The patients received immunizations with lymphocytes and 6 weeks or later were tested for seroconversion of MLR-BFs. Seventeen of these thirty-three patients were evaluated for antipaternal cytotoxic antibodies. The results were correlated with the outcome of the next pregnancy after treatment. RESULTS: Eighty percent of the 33 patients had a live child. Of those patients having success, only 50% produced MLR-BFs. Of those patients having a new loss, five did and two did not produce MLR-BF (P > 0.05). Regarding the 17 patients tested for cytotoxic antibodies, 4 of the 5 patients who tested positive had a new abortion, whereas only 1 of 12 whose tests remained negative did not have gestational success (P < 0.01). CONCLUSION: The presence of MLR-BFs is not a prognostic criterium for the outcome of pregnancy after alloimmunotherapy, and, consequently, it is not a good diagnostic tool for RSA of alloimmune cause.

Human cytotrophoblastic cells absorb the NK blocking activity of monoclonal BA11.

PROBLEM: R80K is a polymorphic alloantigeneic protein present on human placental trophoblast and on paternal B lymphocytes and monocytes. This protein, unlike the former candidate TLX antigen, stimulates a protective maternal immune response in vivo. A murine monoclonal BA11 antibody, directed against R80K, prevents abortion in three murine pregnancy-failure models and inhibits human and murine NK activity. We attempted to define the target of BA11 in the human NK assay system. METHODS: A CELISA method was used to detect R80K antigen on the surface of different cells using the BA11 antibody. The effect, on human peripheral blood NK activity against K562, by BA11 before and after absorption by different cells, including the K562 target, was determined. RESULTS: R80K was detected on term placental syncytio and cytotrophoblast and on BeWo cells, by CELISA. BA11 suppressed NK lysis of K562 cell sin a dose-dependent manner. Absorption of the BA11 by BeWo and by cytotrophoblastic cells significantly decreased the NK-inhibitory activity. There was minimal absorption by K562 and BA11-pretreateed K562 cells remained susceptible to NK lysis. By contrast, BA11-pretreated peripheral blood cells lost all NK activity. CONCLUSIONS: The inhibition of NK killing of K562 cells by BA11 is more complex than simple masking of a trophoblast cell-associated molecule in K562 necessary for recognition in NK cells.

Is the immune system necessary for placental reproduction? A hypothesis on the mechanisms of alloimmunotherapy in recurrent spontaneous abortion.

Recurrent spontaneous abortion is being treated with alloimmunotherapy which consists of the inoculation of allogeneic mononuclear cells. However the mechanisms explaining the benefits of this therapy are not clear yet. Taking the immunotrophic hypothesis as the paradigm of the field of reproductive immunology, hereby we present a hypothesis to propose a role for the immune system in reproduction and at the same time to explain how alloimmunotherapy may work. We base our view on several facts: first, immunodeficient mice reproduce--albeit their progeny may not be as robust and numerous as that from normal individuals. Second, maternal lymphocytes cross the placenta and may induce graft versus host disease. Third, graft versus host disease in newborn F1 mice inoculated with paternal lymphocytes can be prevented by inoculation of the mother with the same paternal lymphocytes before and during pregnancy. We propose that: 1) the immune system by itself is not necessary for placental reproduction; 2) the immune system plays its major role in reproduction by counteracting the allogeneic response generated against the fetus; 3) recurrent spontaneous abortion represents a type of graft versus host disease induced by maternal cells infiltrating the fetus; and 4) alloimmunotherapy induces an antiidiotypic response necessary to counteract the graft versus host reaction in the fetus.

Prevalence of anti-Toxoplasma gondii antibodies in Cebus spp in the Santa Fe Zoological Park of Medellín, Colombia.

The prevalence of anti-Toxoplasma gondii antibodies was studied in 47 nonhuman primates of the Cebus species in the Santa Fe Zoological Park in Medellín, Colombia. Specific IgG titers (greater than 1/64) were detected in 40.9% of C. albifrons studied (n = 22), 13.3% of C. capucinus (n = 15), and 0% of C. apella (n = 10). Specific IgM was not detected in any of the animals studied.