Reproductive Medicine and Biology最新文献

Background: Polycystic ovary syndrome (PCOS) is a complex endocrinopathy, which leads to ovulation dysfunction and infertility, as well as metabolic and mental disorders. Women with PCOS exhibit several characteristic symptoms, with marked heterogeneity across different races and ethnicities.

Methods: In this review, the author outlines the phenotypic disparities of PCOS among various racial and ethnic populations. First, the prevalence of major symptoms in different racial and ethnic groups with PCOS is summarized. Next, the effects of four phenotypes, derived from the Rotterdam criteria for PCOS, on metabolic and reproductive features are recapitulated.

Main findings: A growing body of evidence suggests that East Asian populations exhibit less hirsutism and adiposity compared with other groups. However, hirsutism is more prevalent in South Asian, Middle Eastern, and Hispanic populations. Hispanic and African American populations have more frequent obesity and insulin resistance. With regard to the association between mental disorders and racial and ethnic differences, limited studies exist; therefore, no conclusions can be drawn.

Conclusion: Race and ethnicity-specific factors related to PCOS must be considered in clinical practice. The diagnostic criteria of PCOS should be specific to race and ethnicity to avoid missing treatment opportunities.

Background: As the COVID-19 pandemic nears resolution in 2024, the mechanisms by which SARS-CoV-2 and other viral infections induce spermatogenic dysfunction remain poorly understood. This review examines the mechanisms by which viral infections, particularly COVID-19, disrupt spermatogenesis and highlights the implications for male reproductive health. While reports suggest that spermatogenic dysfunction caused by COVID-19 is mild and transient, these findings may have broader applications in understanding and treating spermatogenic dysfunction caused by future viral infections.

Methods: The PubMed database was searched to identify original and review articles investigating the mechanisms by which viral infections, particularly SARS-CoV-2, contribute to spermatogenic dysfunction.

Main findings: SARS-CoV-2 affects the testis through multiple mechanisms, including ACE2 receptor-mediated entry, direct viral damage, inflammatory response, blood-testis barrier disruption, hormonal imbalance, oxidative stress, and impaired spermatogenesis. The combination of these factors can disrupt testicular function and highlights the complexity of the effects of COVID-19 on male reproductive health.

Conclusion: COVID-19 may disrupt spermatogenesis through direct testicular infection, systemic inflammation, hormonal disruption, and oxidative stress. Ongoing research, vaccination efforts, and clinical vigilance are essential to address these challenges and develop effective treatment and prevention strategies.

Purpose: Uterine leiomyomas (ULMs) are classified into those with and without MED12 mutations (MED12m(+) and MED12m(-), respectively). This study was undertaken to establish a culture system to evaluate the effect of female hormones on the growth of ULM cells in each ULM subtype.

Methods: ULM cells isolated from MED12m(+) or MED12m(-) tissues were cultured in a monolayer for 7 days with four hormone treatments: estrogen (E) and progesterone (P) (E + P), E only (E), P only (P), and medium only (CTRL). They were also cultured in a 3D spheroid culture system with the above four treatments and a fifth treatment: E + P + selective progesterone receptor modulator (E + P + SPRM). The hormonal effects were evaluated based on cell number, spheroid size, and histology.

Results: In the monolayer cultures, female hormones did not cause the proliferation of ULM cells of either subtype. In the spheroid cultures, spheroid sizes for both subtypes were significantly larger with the E + P and P treatments than with the CTRL and E treatments and were comparable in the E and E + P + SPRM treatments. Histological staining showed that collagen fibers were present only in the spheroids of the P-treated groups of MED12m(+).

Conclusion: We established a 3D spheroid culture system to evaluate the effects of female hormones on ULM cells.

Purpose: To investigate the effects of C-type natriuretic peptide (CNP) on human granulosa cell growth and elucidate its regulatory mechanisms.

Methods: A human non-luteinizing granulosa cell line (HGrC) developed from small antral follicles was used to assess the impact of CNP on cell proliferation and estrogen synthesis. cGMP production via the guanylate cyclase domain of the CNP receptor, natriuretic peptide receptor 2 (NPR2), was confirmed. The regulation of CNP encoding natriuretic peptide C (NPPC) and NPR2 by estradiol and oocyte-derived factors (ODFs) was examined.

Results: Besides detecting both NPPC and NPR2, CNP increased cellular proliferation. The specific action of CNP on cell proliferation was confirmed using siRNA transfection. CNP stimulated cGMP production, whereas a guanylate-cyclase inhibitor suppressed CNP-induced cell proliferation. Estradiol production was elevated by CNP treatment, accompanied by increased expression of estrogen synthetic enzymes. Furthermore, CNP upregulated NPR2 expression in cooperation with estradiol and ODFs, while estradiol increased NPPC expression.

Conclusion: This study demonstrates CNP stimulation of human granulosa cell growth and suggests potential cross-talk between these cells and oocytes. Further research on the simultaneous administration of CNP and estradiol may offer a promising approach for promoting early-stage follicle development in infertility treatments for patients with poor ovarian reserve.

Background: Embryologists are crucial in assisted reproductive technology (ART), yet their duties, education, and licensing requirements vary significantly across countries, complicating the determination of optimal staffing levels in ART laboratories. With anticipated advancements such as automation in ART laboratories, this review comprehensively analyzes factors necessary for appropriate future staffing.

Main findings: A comprehensive literature search was conducted using PubMed to identify relevant articles up to July 2024, employing keywords such as "embryologist," "staffing," and "certification." Articles were evaluated for content related to laboratory operations, and guidelines from five organizations regarding licensing and education were compared.

Results: The review revealed significant international differences in embryologist certification, duties, and staffing recommendations. These disparities, along with the integration of advanced ART technologies and regulatory requirements, significantly impact future staffing needs in ART laboratories.

Conclusion: The definitions of an ART cycle and required staffing levels vary across organizations, influenced by the certification and duties of embryologists in different countries. Adequate embryologist staffing is essential for ensuring laboratory quality control and impacting patient ART outcomes. As new technologies and automation reshape laboratory workflows, collaborative efforts among organizations, countries, and embryologist associations are essential for developing comprehensive educational curricula and determining appropriate staffing levels.

Background: Mitosis maintains a genome's genetic information in daughter cells by accurately segregating chromosomes. However, chromosome aberrations are common during early mammalian embryogenesis. Chromosomal abnormalities during the early stages of embryogenesis result in the formation of mosaic embryos, wherein cells with normal genomes coexist with cells exhibiting abnormal genomes. The precise frequency and etiology of such abnormalities remain unclear. It is postulated that these aberrations contribute to the etiology of a number of conditions, including infertility and congenital diseases such as Down's syndrome.

Methods: This review synthesizes current literature and data to elucidate the causes and implications of chromosome aberrations in early mammalian embryos. It places particular emphasis on identifying patterns of mosaicism and investigating the underlying mechanisms responsible for these abnormalities.

Main findings: The underlying causes of chromosome abnormalities in early embryos were examined in the context of DNA replication and embryonic development.

Conclusion: A deeper understanding of chromosome abnormalities in early embryos could help develop new infertility treatments and advance research on cancers caused by these abnormalities. This article reviews current knowledge and gaps in understanding chromosome segregation abnormalities during embryogenesis and future directions in this field.

Purpose: This study aimed to investigate the molecular mechanisms associated with chromosome segregation errors caused by intrinsic oxidative stress during in vitro oocyte maturation (IVM) using oocytes from Sod1-deficient (Sod1KO) mice.

Methods: Ovulated or in vitro matured cumulus-cells oocyte complexes (COCs) were collected from wild-type (WT) and Sod1KO mice and evaluated chromosome alignment, chromosome segregation, meiotic progression, and BUBR1 and REC8 protein expression levels.

Results: In 21% O₂ IVM, the Sod1KO had significantly higher frequencies of chromosome misalignment and segregation errors compared to the WT, and they also reached Germinal Vesicle Break Down (GVBD) and M I stages peak earlier and showed a shorter M I stage residence time compared to the WT. These changes were associated with a decrease in the recruitment of BUBR1 to kinetochores at M I stage, but there were no differences in the expression of REC8 between the two genotypes. Furthermore, the addition of L-ascorbic acid (AsA) or N-acetyl-L-cysteine (NAC) during IVM reduced the frequency of chromosome segregation errors in Sod1KO oocytes.

Conclusions: Oxidative stress caused by Sod1 deficiency during IVM impairs the spindle assembly checkpoint function due to a decrease in the recruitment of BUBR1 to M I stage kinetochores, leading to abnormalities in meiotic progression and chromosome segregation.

Background: Uterine endometrial natural killer (uNK) cells represent major leukocytes in the mid-secretory phase of the cell cycle, and their number is further increased during early pregnancy. The activating and inhibitory receptors expressed on their surface mediate various functions of uNK cells, such as cytotoxicity, cytokine production, spiral artery remodeling, and self-recognition.

Methods: This study reviewed the most recent information (PubMed database, 175 articles included) regarding the activating and inhibitory receptors on uNK cells in human females with healthy pregnancies and the evidence indicating their significance in various reproductive failures.

Main findings: Numerous studies have indicated that the natural cytotoxic receptors, killer cell immunoglobulin-like receptors, and C-type lectin receptors, particularly those expressed on uNK cells, play crucial roles in successful pregnancy.

Conclusion: As studies on human uNK cells are limited owing to the low availability of fertile samples, and the extrapolation of animal models has certain limitations, the in vivo role of uNK cells has not yet been fully elucidated. However, immunotherapies focusing on modulating uNK cell function have been controversial in terms of pregnancy outcomes. Further research is required to elucidate the role of uNK cells in reproduction.

Background: Lipid droplets (LDs) are organelles consisting of a central core of neutral lipids covered by a single layer of phospholipids and are found in most eukaryotic cells. Accumulating evidence suggests that LDs not only store neutral lipids but also coordinate with other organelles for lipid metabolism within cells.

Methods: This review focuses on the synthesis of LDs during follicular development and highlights the factors involved in the regulation of LD biogenesis within the ovary.

Main findings: In the mammalian ovary, the presence of LDs has long been recognized mainly by morphological analysis. However, their distribution in the ovary varies according to the region and cell type; for example, LDs are abundant in the medulla, which has a rich blood vessel network, in interstitial cells, which are the site of steroid production, and surrounding growing follicles, while they are poor in granulosa cells within follicles. LDs are also enriched in the corpus luteum after ovulation and massively accumulate in atretic follicles during follicular growth. Furthermore, LD synthesis is synchronized with angiogenesis during follicular development.

Conclusion: Addressing the functional link between LD biogenesis and angiogenesis is essential for understanding the molecular basis underlying LD biology, as well as the ovarian dysfunction with metabolic disorders.