Editorial: Novel insights into sperm function and selection: from basic research to clinical application

COPYRIGHT © 2023 Li, Luo and Cannarella. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Editorial PUBLISHED 15 June 2023 DOI 10.3389/fendo.2023.1231545


Identifying new gene variants involved in abnormal sperm parameters
Clinical routine testing of semen mainly includes count, motility, and morphology. Motility is included among the most important functional tests. Reduced motility or absent sperm motility, known as asthenozoospermia, often accompanies the abnormal  In summary, these articles focused on the gene variants involved in abnormal sperm parameters. This research field will give new clues about the etiology of unexplained infertility, which will be beneficial for the diagnosis and treatment of male infertility.

Discovering new protein biomarkers of sperm function and quality
Potential protein biomarkers were also reported to be linked with the sperm-zona pellucida (ZP)-binding ability and the quality of the frozen sperm. Leung et al. reported that heat shock protein70 2 (HSPA2) and sperm acrosome associated 3 (SPACA 3) are associated with the sperm ZP-binding ability. The results validated the possibility of applying spermatozoa-ZP interaction to select fertilization-competent spermatozoa in assisted reproductive technology (ART). Arunkumar et al. reported that the temperature equilibration process lowered the abundance of sperm proteins in bull, was involved in energy metabolism, structural integrity, and DNA repair, and increased the abundance of proteins associated with proteolysis and protein degradation. The abundance of proteins associated with signal pathways in sperm, such as metabolism, cyclic guanosine 3', 5'-monophosphate-dependent protein kinase G signaling, and regulation of the actin cytoskeleton.

Reporting new findings on ICSI at the clinical ART lab
One report showed the effect of different sperm preparation techniques on ICSI's clinical outcomes. Li et al. evaluated the effect of different sperm preparation techniques on fertilization rate, cleavage rate, embryo quality, endometrial thickness, implantation, biochemical pregnancy, clinical pregnancy, and live birth rates. They found that different sperm sources did not affect the embryo and clinical outcomes after IVM-ICSI cycles, including percutaneous epididymal sperm aspiration, testicular sperm aspiration, and ejaculated sperm.
Another report analyzed the current status and hotspots of ICSI based on 8271 publications between 2002 and 2021. Shen et al. showed that the hotspot topics of ICSI have been risks of ICSI, oocyte preservation, live birth rate, infertile men, and embryo quality in the past two decades. The top five prolific countries have been USA, China, Italy, Japan, and Belgium; the United States accounted for 22.65% of all publications in 2002; after 2018, four countries, China, UK, Italy, and Spain, increased rapidly, and China accounted for 32.10% of all publications on ICSI from 2018 to 2021. The number of publications from China grew exponentially from only five publications in 2002 to 208 publications in 2021; the top five contributing organizations were the Free University of Brussels, University of Copenhagen, University of Valencia, Ghent University, and the University of California San Francisco; the most productive and cited journals were Fertility and Sterility and Human Reproduction. This study presents a research overview of ICSI from different perspectives. These findings will contribute to a better understanding of the current status of ICSI research and provide hotspots and trends for future studies.
Discussing new developing trends in methods for sperm selection or sperm function evaluation Nixon et al. reviewed recent developments in the understanding of sperm biology and function and highlighted the development of cutting-edge approaches for identifying and treating male infertility. In particular, the review focused on the progress toward the implementation of precision medicine and the application of advanced technology platforms, including whole exome sequencing, proteomic analyses, advanced imaging technologies, and machine learning artificial intelligence. The review showed that the increasing novel mechanistic understanding of sperm biology and function, and the improvement of advanced technology will have a deep impact on many aspects: the uncovered and expanding potential candidate biomarkers, diagnostics, and treatments of male infertility, disrupting the fertility care paradigm, optimizing outcomes for the management of male infertility.
In conclusion, research published in this Research Topic revealed new gene variants and proteins correlated with sperm function and quality, new findings of sperm preparation, the research trends and hotspots on ICSI at clinical ART labs, and new developing trends in methods for sperm selection or function evaluation. This Research Topic has increased the insights from basic research of the genes and proteins that may affect sperm function and sperm selection to clinical application, which is beneficial for the fields of reproductive biology and reproductive medicine.

Author contributions
KL, TL, and RC drafted and revised the manuscript. All authors have read and confirmed this editorial for publication.