Germ cell apoptosis in the human testis Martincic, D S; Virant Klun, I; Zorn, B ...
Pflügers Archiv,
01/2001, Letnik:
442, Številka:
6 Suppl 1
Journal Article
Recenzirano
Apoptosis is a widespread phenomena during development. It represents a form of cell death and has a crucial role in tissue homeostasis. Apoptosis is also involved in a number of pathological ...conditions. Spermatogenesis is a dynamic process of germ cell proliferation and differentiation. During regular spermatogenesis, the number of testicular germ cells degenerate by an apoptotic process. The significance of regulating cell population by apoptosis is more apparent when sperm production is halted. The presence and frequency of apoptosis in germ cells of human testis biopsy specimens were tested. The results confirm the presence of germ cell apoptosis but not the apoptosis of Sertoli cells. The increased apoptotic index was observed in patients with azoospermia in comparison with normal but obstructed spermatogenesis.
Elastase-inhibitor complex was assessed by immunoassay in the seminal plasma of 312 men attending the outpatient infertility clinic. Using receiver operating characteristic (ROC) curve analysis, ...elastase at the cut-off value of > or =290 ng/ml was shown to be efficient (sensitivity 79.5%, specificity 74.4%) in the detection of genital tract inflammation as defined by leukocytospermia (>1x106 leukocytes/ml). The prevalence of increased elastase in 292 infertile men was significantly higher (34%) as compared with that (5%) observed in 20 fertile men (P = 0.02). Moreover, high elastase concentration (> or =290 ng/ml) was observed in 66 of the 264 men (25%) without leukocytospermia. A significant positive correlation was found between elastase concentration and patient age (r = 0.202, P < 0.0001) and the number of leukocytes (r = 0.330, P < 0.0001). A negative correlation was found between elastase concentration and semen volume (r = -0.146, P = 0.01) and the percentage of spermatozoa with single-stranded DNA (r = -0.194, P = 0.024), but there was no correlation between elastase and sperm reactive oxygen species production. A higher seminal elastase concentration was significantly associated with tubal damage in female partners (P < 0.001). After norfloxacine antibiotic therapy, decrease in elastase concentration was observed in 15 (25%) of the 60 treated patients. Tubal damage in the partner negatively affected the response to antibiotic therapy. In conclusion, granulocyte elastase is a reliable screening test for silent genital tract inflammation of the couple. The elastase-inhibitor complex may have a protective effect in reducing sperm DNA denaturation.
To determine whether semen quality in Slovenians has changed over 14 years (1983–96), we analysed retrospectively the semen of 2343 healthy men with a normal spermiogram, who were partners of women ...with tubal infertility included in the IVF‐ET programme. Age at semen collection, duration of sexual abstinence, semen volume, sperm concentration, total sperm count, percentage of spermatozoa with progressive motility, and normal morphology were determined. Multiple regression analysis was used to assess the changes in sperm characteristics according to the year of semen collection, year of the man's birth and the duration of sexual abstinence. Semen volume, sperm concentration, sperm count and total sperm motility did not change between 1983 and 1996, whereas between 1988 and 1996 rapid progressive sperm motility decreased by 0.95% per year (p < 0.0001). Semen volume, sperm concentration, and sperm count increased with duration of sexual abstinence. After adjustment for the year of semen collection and duration of sexual abstinence, multiple regression analysis showed that sperm concentration decreased by 0.67% per each successive year of birth (p = 0.03). Thus the sperm concentration decreased from 87.6 × 106/mL in men born in the 1940s to 77.3 × 106/mL in those born between 1956 and 1960. After 1960, sperm concentration was found to increase. In 2343 healthy men, no decline in semen quality, except in rapid progressive motility, was observed in the study period. Lower sperm concentration was found among men born between 1950 and 1960. This could be related to worse socio‐economic status, stress or negative environmental factors in this time period.
The aim of the present study was to assess variability in the evaluation of human sperm concentration, motility and vitality. Technicians and biologists from 10 teams involved in multicentre studies ...on semen quality attended the same laboratory, each team using its own methods and equipment to analyse the same semen samples. Inter-individual variability was assessed from 17 fresh semen samples of varying quality. Intra-individual variability was assessed from pools of frozen samples for sperm concentration and motility and stained smears for vitality with three blind evaluations by sample and smear. The mean inter-individual coefficients of variation were 22.9, 21.8 and 17.5% for sperm concentration, motility and vitality respectively. There was no statistical difference among participants for sperm concentration assessment, but significant differences for both motility and vitality (both P < 0.05). The mean intra-individual coefficients of variation were 15.8, 26.2 and 13.1% for sperm concentration, motility and vitality respectively, with marked differences between expert and novice participants: concentration 9.8% versus 28.0%; motility 22.8% versus 33.0%; and vitality 10.0% versus 19.3%. The present data confirm the need for external quality control schemes for diagnostic purposes, and indicate their utmost importance in multicentre studies on semen quality.
Purpose
In this review, the current knowledge on anti-Müllerian hormone (AMH) is presented, concerning its value in disease and IVF treatment as well as in terms of its prospective clinical use.
...Methods
AMH is becoming the most appropriate biomarker for the ovarian reserve measured predominantly for assisted reproductive treatment (ART) patients in comparison to the currently used antral follicle count (AFC). However, this is not the only way AMH measurements can be used in the clinics. Because of this, we reviewed the current literature for the use of AMH in current or prospective clinical practice.
Results
We found that AMH has a high predictive value in assessing the ovarian reserve, which can lead to a better efficiency of in vitro fertilization (IVF) procedures. It has a high potential to be developed as a staple diagnostic marker of ovarian disease, especially for ovarian cancers and even as a possible treatment tool for certain cancers. It could potentially be used to prevent oocyte loss due to chemo- or radiotherapy.
Conclusion
AMH is an important hormone especially in women reproductive organs and is currently seen as the best biomarker for a multitude of uses in reproductive medicine. Currently, the biggest issue lies in the lack of international standardization of AMH. However, it is encouraging to see that there is interest in AMH in the form of research on its action and use in reproductive medicine.
Oocytes undergo a range of complex processes via oogenesis, maturation, fertilization, and early embryonic development, eventually giving rise to a fully functioning organism. To understand proteome ...composition and diversity during maturation of human oocytes, here we have addressed crucial aspects of oocyte collection and proteome analysis, resulting in the first proteome and secretome maps of human oocytes. Starting from 100 oocytes collected via a novel serum-free hanging drop culture system, we identified 2,154 proteins, whose function indicate that oocytes are largely resting cells with a proteome that is tailored for homeostasis, cellular attachment, and interaction with its environment via secretory factors. In addition, we have identified 158 oocyte-enriched proteins (such as ECAT1, PIWIL3, NLRP7)1 not observed in high-coverage proteomics studies of other human cell lines or tissues. Exploiting SP3, a novel technology for proteomic sample preparation using magnetic beads, we scaled down proteome analysis to single cells. Despite the low protein content of only ∼100 ng per cell, we consistently identified ∼450 proteins from individual oocytes. When comparing individual oocytes at the germinal vesicle (GV) and metaphase II (MII) stage, we found that the Tudor and KH domain-containing protein (TDRKH) is preferentially expressed in immature oocytes, while Wee2, PCNA, and DNMT1 were enriched in mature cells, collectively indicating that maintenance of genome integrity is crucial during oocyte maturation. This study demonstrates that an innovative proteomics workflow facilitates analysis of single human oocytes to investigate human oocyte biology and preimplantation development. The approach presented here paves the way for quantitative proteomics in other quantity-limited tissues and cell types. Data associated with this study are available via ProteomeXchange with identifier PXD004142.
Data from the literature show that there are different populations of stem cells present in human adult ovaries, including small stem cells resembling very small embryonic-like stem cells (VSELs). ...These small ovarian stem cells with diameters of up to 5 μm are present in the ovarian surface epithelium and can grow into bigger, primitive oocyte-like cells that express several markers of a germinal lineage and exhibit pluripotency but not the zona pellucida structure when cultured in vitro. In this report, we present the results of the functional testing of such primitive oocyte-like cells from one patient with premature ovarian failure after insemination with her partners’ sperm. Knowing that even immature oocytes collected in an in vitro fertilization program cannot be fertilized naturally, we were only interested in determining whether and how these cells react to added sperm and whether spermatozoa somehow “recognize” them. Interestingly, the primitive oocyte-like cells quickly released a zona pellucida-like structure in the presence of sperm. Two different populations of cells were distinguished, those with a thick and those with a thin zona pellucida-like structure. The primitive oocyte-like cells with a released zona pellucida-like structure expressed the pluripotency-related gene
OCT4A
(
POU5F1
) and zona pellucida-related gene
ZP3
, similar to oocytes obtained from in vitro fertilization but not somatic chondrocytes. In a small proportion of these cells, a single-spermatozoon was observed inside the cytoplasm, but no signs of fertilization were found. These observations may suggest a primitive “cortical reaction”. Our data further confirm the presence of germinal stem cells in the ovarian surface epithelium cell culture.
In addition to a number of scientific and medical questions about SARS-CoV-2 infection that still need to be answered, there is also the question of how this highly virulent virus and COVID-19 ...disease affect gametogenesis in humans. Even more important is the question of whether the virus can also enter and infect oocytes and possibly alter them in an unknown way, which could also affect the development and status of the human embryo. The answers to these questions are still poorly known, so we reviewed the human oocyte transcriptome and proteome obtained in our previous studies and found that human oocytes from the in vitro fertilization program expressed both the ACE2 and BSG genes and the corresponding ACE2 and BSG proteins. This means that human oocytes possess the molecular 'machinery' to facilitate SARS-CoV-2 entrance and infection. According to various studies, especially in animal models, different viruses can infect oocytes, so infection of the oocyte with SARS-Cov-2 cannot be completely ruled out. A hypothetical model of human oocyte infection with this virus has been proposed.
Small stem cells with diameters of up to 5 μm previously isolated from adult human ovaries indicated pluripotency and germinal lineage, especially primordial germ cells, and developed into primitive ...oocyte-like cells in vitro. Here, we show that a comparable population of small stem cells can be found in the ovarian tissue of women with borderline ovarian cancer, which, in contrast to small stem cells in "healthy" ovaries, formed spontaneous tumour-like structures and expressed some markers related to pluripotency and germinal lineage. The gene expression profile of these small putative cancer stem cells differed from similar cells sorted from "healthy" ovaries by 132 upregulated and 97 downregulated genes, including some important forkhead box and homeobox genes related to transcription regulation, developmental processes, embryogenesis, and ovarian cancer. These putative cancer stem cells are suggested to be a novel population of ovarian tumour-initiating cells in humans.
It has been suggested that hematopoietic stem/progenitor cells (HSPCs) could become specified from a population of migrating primordial germ cells (PGCs), precursors of gametes, during embryogenesis. ...Some recent experimental data demonstrated that the cell population that is usually considered to be PGCs, moving toward the gonadal ridges of an embryo, contains a subset of cells coexpressing several germ cell and hematopoietic markers and possessing hematopoietic activity. Experimental data showed that bone morphogenetic protein 4 (BMP4) generates PGCs from mouse bone marrow-derived pluripotent stem cells. Interestingly, functional reproductive hormone receptors have been identified in HSPCs, thus indicating their potential role in reproductive function. Several reports have demonstrated fertility restoration and germ cell generation after bone marrow transplantation in both animal models and humans. A potential link between HSPCs and germinal lineage might be represented by very small embryonic-like stem cells (VSELs), which have been found in adult human bone marrow, peripheral blood, and umbilical cord blood, express a specific pattern of pluripotency, germinal lineage, and hematopoiesis, and are proposed to persist in adult tissues and organs from the embryonic period of life. Stem cell populations, similar to VSELs, expressing several genes related to pluripotency and germinal lineage, especially to PGCs, have been discovered in adult human reproductive organs, ovaries and testicles, and were related to primitive germ cell-like cell development in vitro, thus supporting the idea of VSELs as a potential link between germinal lineage and hematopoiesis.
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