NCT01762098.

BACKGROUND The best-known role of spermatozoa is to fertilize the oocyte and to transmit the paternal genome to offspring. These highly specialized cells have a unique structure consisting of all the elements absolutely necessary to each stage of fertilization and to embryonic development. Mature spermatozoa are made up of a head with the nucleus, a neck, and a flagellum that allows motility and that contains a midpiece with a mitochondrial helix. Mitochondria are central to cellular energy production but they also have various other functions. Although mitochondria are recognized as essential to spermatozoa, their exact pathophysiological role and their functioning are complex. Available literature relative to mitochondria in spermatozoa is dense and contradictory in some cases. Furthermore, mitochondria are only indirectly involved in cytoplasmic heredity as their DNA, the paternal mitochondrial DNA, is not transmitted to descendants. OBJECTIVE AND RATIONAL This review aims to summarize available literature on mitochondria in spermatozoa, and, in particular, that with respect to humans, with the perspective of better understanding the anomalies that could be implicated in male infertility. SEARCH METHODS PubMed was used to search the MEDLINE database for peer-reviewed original articles and reviews pertaining to human spermatozoa and mitochondria. Searches were performed using keywords belonging to three groups: ‘mitochondria’ or ‘mitochondrial DNA’, ‘spermatozoa’ or ‘sperm’ and ‘reactive oxygen species’ or ‘calcium’ or ‘apoptosis’ or signaling pathways’. These keywords were combined with other relevant search phrases. References from these articles were used to obtain additional articles. OUTCOMES Mitochondria are central to the metabolism of spermatozoa and they are implicated in energy production, redox equilibrium and calcium regulation, as well as apoptotic pathways, all of which are necessary for flagellar motility, capacitation, acrosome reaction and gametic fusion. In numerous cases, alterations in one of the aforementioned functions could be linked to a decline in sperm quality and/or infertility. The link between the mitochondrial genome and the quality of spermatozoa appears to be more complex. Although the quantity of mtDNA, and the existence of large-scale deletions therein, are inversely correlated to sperm quality, the effects of mutations seem to be heterogeneous and particularly related to their pathogenicity. WIDER IMPLICATIONS The importance of the role of mitochondria in reproduction, and particularly in gamete quality, has recently emerged following numerous publications. Better understanding of male infertility is of great interest in the current context where a significant decline in sperm quality has been observed.

Objective: To develop a consensus on the diagnostic criteria for chronic endometritis (CE) at hysteroscopy (HSC), and to evaluate these proposed criteria in a randomized-controlled observer study. Design: Systematic review of studies evaluating the diagnostic accuracy of HSC in CE diagnosis; Delphi consensus on hysteroscopic diagnostic criteria for CE; randomized-controlled observer study to evaluate the reproducibility of the proposed diagnostic criteria. Setting: Not applicable. Participant(s): Experts from different countries were involved in the systematic review and contributed to the Delphi consensus. Physicians from different countries were involved in the observer study. Intervention(s): After reaching consensus on the diagnostic criteria, the Delphi poll created a questionnaire including 100 hysteroscopic pictures (50 from women with CE [domain 1] and 50 from women without CE [domain 2]), with a single question per picture (Answer_A: suggestive of CE; answer B: not suggestive of CE). A total of 200 physicians were invited to take part in the observer study. Before completing the questionnaire, physicians were randomized to receive a description of the diagnostic criteria (group A) or no such information (group B). Main Outcome Measure(s): The primary outcome was to compare the questionnaire scores for the two groups of observers. The secondary outcome was to assess the interobserver agreement in the diagnosis of CE in each group. Result(s): A total of 126 physicians completed the questionnaire (62 in group A and 64 in group B). Observers in group A obtained higher total scores compared with those in group B (P< .001). Specifically, group A showed higher mean score in domain 1 (P< .001), but not in domain 2 (P¼ .975). A substantial agreement was found among observers in group A (intraclass correlation coefficient [ICC] 0.78), whereas a fair agreement was found among observers in group B (ICC 0.40). Conclusion(s):This randomized-controlled observer study found a positive impact of our criteria on physicians' ability to recognize CE. (Fertil Steril Ò 2019;112:162-73. Ó2019 by American Society for Reproductive Medicine.) El resumen está disponible en Español al final del artículo.

This work was supported by the University Hospital of Angers, the University of Angers, France, and the French national research centres INSERM and the CNRS. There were no competing interests.

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