Résumé
Despite advances in the field of male reproductive health, idiopathic male infertility, in which a man has altered semen characteristics without an identifiable cause and there is no female factor infertility, remains a challenging condition to diagnose and manage. Increasing evidence suggests that oxidative stress (OS) plays an independent role in the etiology of male infertility, with 30% to 80% of infertile men having elevated seminal reactive oxygen species levels. OS can negatively affect fertility via a number of pathways, including interference with capacitation and possible damage to sperm membrane and DNA, which may impair the sperm's potential to fertilize an egg and develop into a healthy embryo. Adequate evaluation of male reproductive potential should therefore include an assessment of sperm OS. We propose the term Male Oxidative Stress Infertility, or MOSI, as a novel descriptor for infertile men with abnormal semen characteristics and OS, including many patients who were previously classified as having idiopathic male infertility. Oxidation-reduction potential (ORP) can be a useful clinical biomarker for the classification of MOSI, as it takes into account the levels of both oxidants and reductants (antioxidants). Current treatment protocols for OS, including the use of antioxidants, are not evidence-based and have the potential for complications and increased healthcare-related expenditures. Utilizing an easy, reproducible, and cost-effective test to measure ORP may provide a more targeted, reliable approach for administering antioxidant therapy while minimizing the risk of antioxidant overdose. With the increasing awareness and understanding of MOSI as a distinct male infertility diagnosis, future research endeavors can facilitate the development of evidence-based treatments that target its underlying cause.
Sujets)
Femelle , Humains , Mâle , Antioxydants , Classification , Protocoles cliniques , Diagnostic , ADN , Structures de l'embryon , Fécondité , Dépenses de santé , Infertilité , Infertilité masculine , Membranes , Ovule , Oxydants , Oxydoréduction , Stress oxydatif , Espèces réactives de l'oxygène , Réducteurs , Santé reproductive , Sperme , Spermatozoïdes , Vedettes-matièreRésumé
Leptin, an adipocyte-derived hormone, serves numerous physiological functions in the body, particularly during puberty and reproduction. The exact mechanism by which leptin activates the gonadotropin-releasing hormone (GnRH) neurons to trigger puberty and reproduction remains unclear. Given the widespread distribution of leptin receptors in the body, both central and peripheral mechanisms involving the hypothalamic-pituitary-gonadal axis have been hypothesized. Leptin is necessary for normal reproductive function, but when present in excess, it can have detrimental effects on the male reproductive system. Human and animal studies point to leptin as a link between infertility and obesity, a suggestion that is corroborated by findings of low sperm count, increased sperm abnormalities, oxidative stress, and increased leptin levels in obese men. In addition, daily leptin administration to normal-weight rats has been shown to result in similar abnormalities in sperm parameters. The major pathways causing these abnormalities remain unidentified; however, these adverse effects have been attributed to leptin-induced increased oxidative stress because they are prevented by concurrently administering melatonin. Studies on leptin and its impact on sperm function are highly relevant in understanding and managing male infertility, particularly in overweight and obese men.
Sujets)
Animaux , Humains , Mâle , Infertilité masculine/physiopathologie , Leptine/physiologie , Obésité/complications , Surpoids/complications , Reproduction/physiologieRésumé
Since its inception in 2008, the American Center for Reproductive Medicine's summer internship program in reproductive research and writing has trained 114 students from 23 states within the United States and 10 countries worldwide. Its fundamental goal is to inspire pre-medical and medical students to embrace a career as a physician-scientist. During this intensive course, established scientists and clinicians train interns in the essential principles and fundamental concepts of bench research and scientific writing. Over the first six years (2008~2013), interns have collectively published 98 research articles and performed 12 bench research projects on current and emerging topics in reproductive medicine. Interns have also developed and honed valuable soft skills including time management, communication and presentation skills, as well as life values, which all enhance personal and professional satisfaction. Program graduates are able to recognize the value of medical research and its potential to impact patient care and gain insight into their own career pathway. Between 2011 and 2014, the internship program was thrice awarded a Scholarship in Teaching Award by Case Western Reserve School of Medicine for its innovative teaching approach and positive impact on medical education and student careers. This report highlights the demographics, logistics, implementation, feedback, and results of the first six years of the American Center for Reproductive Medicine's summer internship program at Cleveland Clinic (Cleveland, OH, USA). This may be helpful to other research and academic institutions considering implementing a similar program. In addition, it creates awareness among potential physician-scientists of what the world of research has to offer in both scientific writing and bench research. Finally, it may stimulate further discussion regarding narrowing the gap between physicians and scientists and refinement of the current program.