Study question Does advancing male age influence the frequency of occurrence of sperm abnormalities? Summary answer Advancing male age was associated with increased incidence of certain head and tail defects – elongated head, nuclear vacuoles, and coiled tail. What is known already Evaluation of male reproductive potential is based mainly on sperm motility and sperm morphology. Morphological sperm features serve as a reliable indicator in predicting the fertilizing capacity of sperm. Nowadays, there are various sperm selection techniques based on sperm morphology. However, advancing male age has been associated with decrease in semen quality. Therefore, the aim of this study was to examine the effect of aging on the frequency of occurrence of sperm abnormalities. Study design, size, duration This retrospective study includes 3980 men aged between 15 and 72 years, with a mean of 36 years. Semen samples were collected between October 2015 and December 2022 in a private in-vitro hospital. Men were divided into three groups according to their age: 1) from 15 to 25 years (n = 144), 2) from 25 to 45 years (n = 3447), and 3) over 45 years (n = 393). Participants/materials, setting, methods Sperm morphology was evaluated according to the Kruger’s strict criteria. Totally, 23 types of abnormalities were determined. Head defects included small, large, amorphous, elongated, round, pear-shaped, double, detached head, acephalic cells, small or large acrosomal areas, and spermatozoa without acrosome. Midpiece defects included thick, thin, bent, asymmetric midpiece and cytoplasmic droplets. Tail defects included short, coiled, and double tail. Acrosomal vacuoles and nuclear vacuoles were also evaluated. Statistics: ANOVA, followed by LSD post-hoc test. Main results and the role of chance The results are presented as mean±SD. Among the studied population the percentage of normozoospermic men was 44%, while the percentage of teratozoospermic semen samples was 56%. The total mean frequencies of occurrence of head, midpiece and tail abnormalities were 85.9±7.9%, 34.1±12.8% and 4.7±5.1%, respectively. Only 3 (13%) of the analysed 23 types of sperm abnormalities were significantly more common with advanced male age – elongated head, nuclear vacuoles, and coiled tail.The frequency of occurrence of elongated head differed significantly between the age groups 1-2, and 1-3: 11.38±10.1% vs. 13.79±11.58%, p = 0.015, and 11.38±10.1% vs. 14.4±11. 8%, p = 0.008, respectively. No difference in the incidence of this defect was observed between groups 2 and 3 (p > 0.05).Furthermore, the frequency of nuclear vacuoles significantly increased with age as observed in the following age group comparisons 1-2, 1-3, and 2-3: 4.28±4.93% vs. 5.4±6.1%, p = 0.04, 4.28±4.93% vs. 6.48±7.89%, p < 0.001, and 5.4±6.1% vs. 6.48±7.89%, р=0.001, respectively.Finally, coiled tail was observed more frequently in age groups 2 and 3 compared to age group 1: 13.79±11.58% vs. 11.38±10.1%, p < 0.001, and 14.4±11. 8% vs. 11.38±10.1%, p < 0.001, respectively. Limitations, reasons for caution This is a single-institution retrospective study. Wider implications of the findings The findings of this study showed that aging is associated with an increased percentage of several sperm abnormalities: spermatozoa with elongated head, nuclear vacuoles, and coiled tail. Further studies are required to clarify the negative impact of aging on spermatogenesis leading to morphological defects. Trial registration number NA
It is an acknowledged fact that SARS-CoV-2 exhibits tropism for the human placenta. A possible mechanism of SARS-CoV-2 entry into host cells is via angiotensin-converting enzyme 2 (ACE2) receptors, which are expressed in trophoblasts, endothelial cells, and macrophages. The present study describes a case of spontaneous miscarriage in the 20th gestational week after maternal SARS-CoV-2 infection. The placenta and various fetal organs were examined for structural alterations and expression of the viral nucleocapsid protein and several immune cell markers via immunohistochemistry (IHC). Histopathological examination of the placenta revealed acute chorioamnionitis, acute subamnionic placentitis, multiple intervillous thrombi, increased fibrinoid deposition, and necrotic changes of the chorionic villi. Immunohistochemistry confirmed the presence of SARS-CoV-2 nucleocapsid protein regions predominantly in the syncytiotrophoblast. Staining of the placental tissue for different markers helped elucidate the distribution of immune cells. Pathomorphological examination of the fetal organs demonstrated changes in microcirculation with the presence of sludge phenomenon and diapedesis haemorrhages, mostly in the lungs, brain, and myocardium. IHC staining of fetal organs revealed expression of SARS-CoV-2 nucleocapsid protein, which was detected to the highest extent in the brain, lungs, and liver. The findings of the present report support the hypothesis of possible vertical transmission of SARS-CoV-2 from mother to fetus.
Study question Is the percentage of endometrial stem cells linked to serum progesterone, serum estradiol, and their receptors expression in human endometrium during the mid-luteal phase? Summary answer We found an association between CD117+ endometrial stem cells and serum progesterone, estradiol, as well as with the expression of their receptors in the endometrium. What is known already Various types of stem cells including NOTCH1+ and CD117+ stromal cells have been found in the endometrium. Their quantities have been hypothesised to fluctuate with the menstrual cycle and to have a link with endometrial receptivity. It has been well established that progesterone and estradiol play a crucial role in the preparation of the endometrium for implantation and the expression of their receptors also varies with the menstrual cycle. Nonetheless, the relationship between stem cells and other established markers of endometrial receptivity, such as the sex hormones signaling system, constitutes a novel field of research. Study design, size, duration The present observational study included 87 women aged 26-56 (mean 39.5 years old) undergoing in-vitro fertilisation and for whom a peripheral blood sample and an endometrial biopsy were obtained during the mid-luteal phase (LH + 7) of a natural cycle. Immunohistochemical (IHC) markers for NOTCH1 (E-AB-12815, Elabscience), CD117 (CD117/c-Kit/SCF-Receptor RB-9038-RQ, Epredia), progesterone (PR) and estrogen receptors (ER) (1-PR026-07, 1-ES006-07, Quartett) were used to stain endometrial tissue. The investigation was carried out between March 2020 and January 2022. Participants/materials, setting, methods Serum progesterone and estradiol were measured via electrochemiluminescence using Cobas e411 analyser (Roche Diagnostics, Germany) on the day of obtaining the endometrial biopsy. Stem cells (count and percentage) and the expression of hormone receptors (6-point scale) were determined using ImageJ. Stem cells percentage was compared between groups with high and low progesterone (analogously for estradiol) using Wilcoxon signed-rank test. To assess the link between stem cell percentages and receptor expression, Spearman correlation was used. Main results and the role of chance The mean percentage of positively stained NOTCH1 endometrial stromal stem cells was 0.13 ± 0.29% and CD117+ cells was 0.034 ± 0.039%. The hormone serum levels ranged from 0.2 to 60 ng/mL (median of 14.9 ng/mL) for progesterone and from 12 to 1985 pg/mL (median of 135.6 pg/mL) for estradiol. While the quantities of the two stem cell types demonstrated a positive correlation with each other (R = 0.379, p < 0.001), the percentage of NOTCH1+ stem cells showed no difference between the studied serum hormone levels (p > 0.05), nor revealed a relationship with the expression of their receptors (p > 0.05). In contrast, the amount of CD117+ cells differed significantly between patients with high and low serum progesterone (cutoff 14.9 ng/mL, p = 0.001) and estradiol levels (cutoff 135.6 pg/mL, p = 0.019). Furthermore, the quantity of stem cells positive for CD117 correlated positively with the two hormone receptor levels in the endometrium – PR (R = 0.277, p = 0.019) and ER (R = 0.318, p = 0.007). Limitations, reasons for caution A limitation of the study was the sample size. These findings should be confirmed using a larger population. In addition, confounding variables such as the immunological profile of the tissue should also be taken into account. Wider implications of the findings This study shows that certain endometrial stem cell types (CD117+) but not others (NOTCH1+) are associated with sex hormone signaling during the mid-luteal phase. This relationship highlights the role these cells play in preparing the endometrium for embryo implantation and their quantity might be an indirect indicator of endometrial receptivity. Trial registration number not applicable
Study question Is there a relationship between the percentage of stem cells in human endometrial stroma during the mid-luteal phase of the menstrual cycle and implantation success? Summary answer Women with successful implantation have significantly higher percentage of endometrial stromal CD117-positive stem cells during the mid-luteal phase of the menstrual cycle. What is known already Human endometrium as a highly regenerative dynamic tissue has a population of certain types of adult stem cells localized in the stroma and epithelium. These cells, including mesenchymal and hematopoietic stromal stem cells, participate in the immense cellular turnover in the human endometrium before and during the implantation process. General adult stem cell markers such as CD117 and NOTCH1 have been identified in human endometrium. However, there is a scarce data about the quantity of these endometrial stromal stem cells and their influence on the process of implantation. Study design, size, duration This is a cohort study of 109 women who had an endometrial biopsy during the mid-lutheal phase (LH + 7) in a natural cycle and positive or negative hCG test after in-vitro fertilization (IVF) with euploid embryos within 6 months of biopsy. We used immunohistochemical biomarkers NOTCH1 (E-AB-12815, Elabscience), CD117 (CD117/c-Kit/SCF-Receptor) (RB-9038-RQ, Epredia), to identify stem cells in endometrial stroma. The study was conducted between March 2020 and January 2022. Participants/materials, setting, methods The percentages of NOTCH1-positive and CD117-positive stem cells in the stroma were calculated after enumeration by two independent investigators in multiple endometrial sections. After embryo transfer women were divided into the following groups: unsuccessful embryo implantation (negative hCG test) ( n = 45) and successful implantation (positive hCG test) ( n = 64). The percentage of NOTCH1-positive and CD117-positive cells in the endometrial stroma were compared between these groups through Wilcoxon signed-rank test. Main results and the role of chance The percentage of CD117-positive stem cells in the endometrial stroma ranged between 0% and 0.21%, with a median of 0.02%. The percentage of NOTCH1-positive stem cells in the endometrial stroma ranged between 0.003% and 2.11%, with a median of 0.06%. There was no significant difference in female age (years), BMI (kg/m2) and blastocyst quality between the studied patient groups (P < 0.05). The quantity of NOTCH1-positive cells also did not differ significantly between the two groups (P = 0.18). However, the mean percentage of CD117-positive stromal cells was significantly higher in women with successful implantation compared to patients with unsuccessful implantation (0.04% vs. 0.02%, respectively, P = 0.004). The optimal successful implantation cut-off value for the percentage of CD117-positive stromal cells, was 0.018% (AUC 0.67, 95% CI 0.56-0.77). Therefore, a percentage of 0.018% of CD117-positive stem cells in the endometrial stroma was associated with 63.1% sensitivity and 61.4% specificity for predicting successful implantation after IVF. Limitations, reasons for caution The study cohort was limited in sample size. Not all confounding factors such as potential immunological and genetic reasons for unsuccessful implantation have been taken into account. In addition, the endometrial biopsy could also have an effect on endometrial receptivity and pregnancy outcome. Wider implications of the findings The results of this study revealed that the quantity of certain types of stem cells is associated with successful embryo implantation. These findings emphasize the essential impact of stem cells in human endometrium on the process of implantation. Trial registration number not applicable
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