-
Frontiers in Cell and Developmental... 2020The presence of cellular fragments in the perivitelline space is a commonly used parameter to determine quality before transfer of produced (IVP) embryos. However, this...
The presence of cellular fragments in the perivitelline space is a commonly used parameter to determine quality before transfer of produced (IVP) embryos. However, this parameter is difficult to assess after blastocyst expansion. In this study, we used mechanical hatching to confirm the presence of cellular fragments in the perivitelline space of bovine IVP blastocysts. We further looked for associations between possible apoptosis within extruded cells/ cellular fragments and the quality of bovine blastocysts using quantitative RT-PCR and immunofluorescence. Surprisingly, more than 42% of expanded blastocysts had cellular fragments in the perivitelline space; however, more than 37% of extruded cells were TUNEL negative. We observed no significant difference in embryo quality between expanded blastocysts with and without cellular fragments in the perivitelline space. Overall, our data suggest that embryos extrude abnormal cells to maintain their developmental potential. The presence of fragmented cells is not an indicator of embryo quality.
PubMed: 33469540
DOI: 10.3389/fcell.2020.616801 -
Journal of the Turkish German... 2014In assisted reproductive technology (ART), high embryo quality is closely related to high-quality oocytes. Cytoplasmic maturation and extracytoplasmic maturation are the...
OBJECTIVE
In assisted reproductive technology (ART), high embryo quality is closely related to high-quality oocytes. Cytoplasmic maturation and extracytoplasmic maturation are the most important components in determining oocyte quality. One of the most important components of extracytoplasmic maturation is perivitelline abnormalities. The aim of this study is to determine the effect of perivitelline abnormalities on the development of high-quality embryos.
MATERIAL AND METHODS
The study material consisted of 217 of 1154 oocytes from 98 intracytoplasmic sperm injection (ICSI) cycles undertaken due to male factor infertility. Only cycles with long gonadotropin-releasing hormone analogs combined with recombinant Follicle-stimulating hormone (rec-FSH) were included in study. We compared 105 metaphase-II oocytes that had dominantly perivitelline space abnormalities (large perivitelline space with or without granules) with 112 normal metaphase-II oocytes, based on the embryo grade determined by Alpha Scientists in Reproductive Medicine and the European Society of Human Reproduction and Embryology (ESHRE) Special Interest Group of Embryology. Normal metaphase-II oocytes were characterized by a round, clear zona pellucida; a small perivitelline space containing a single unfragmented first polar body; and a pale, moderately granular cytoplasm with no inclusions.
RESULTS
The development rates of Grade I, II, and III embryos were 68.5%, 23.8%, and 7.7%, respectively, in the 105 oocytes with perivitelline abnormalities. The development rates of Grade I, II, and III embryos were 82.1%, 17.9%, and 0%, respectively, in the 112 morphologically normal oocytes. When compared with normal oocytes, Grade I (68.5% vs. 82.1%, p value; 0.019) and Grade III (7.7% vs. 0%, p value; 0.003) embryo development rates were significantly lower in oocytes that had perivitelline abnormalities.
CONCLUSION
It is important to analyze oocyte quality using multiple parameters, including the perivitelline space. Perivitelline space abnormalities might negatively affect embryo development in male factor-infertile couples that are stimulated with rec-FSH. Therefore, when choosing embryos for transfer, we must take into consideration the historical oocyte data.
PubMed: 25317044
DOI: 10.5152/jtgga.2014.13091 -
Reproductive Medicine and Biology Mar 2011The size of the perivitelline space and the incidence of polyspermy were observed in ovulated and cultured oocytes from rabbits and hamsters with or without treatment by...
PURPOSE
The size of the perivitelline space and the incidence of polyspermy were observed in ovulated and cultured oocytes from rabbits and hamsters with or without treatment by 4-methylumbelliferone (MU), an inhibitor of hyaluronic acid (HA) synthase, in order to examine the relationship between the incidence of polyspermy and the size of the perivitelline space. The amount of HA in the medium with MU-treated hamster oocytes was measured and compared with that in the medium with untreated oocytes.
METHODS
The perivitelline space of oocytes with 1st polar bodies was measured by use of a micrometer under a microscope, and the incidence of polyspermy was observed in the oocytes after insemination. The amount of HA in the medium was examined using an enzyme-linked immunosorbent assay. The distribution of cortical granules was observed by staining with FITC-conjugated LCA.
RESULTS
In both rabbit and hamster, the mean size of the perivitelline space was significantly smaller and the incidence of polyspermy was significantly higher in the cultured and MU-treated oocytes than in the ovulated and untreated oocytes. The mean amount of HA in the medium with MU-treated oocytes (8.96 pg) was significantly smaller than that in the medium with untreated oocytes (21.77 pg). The distribution of cortical granules did not differ among the ovulated, cultured, and MU-treated oocytes.
CONCLUSIONS
These findings suggest that the size of the perivitelline space is closely related to the incidence of polyspermy, and that the oocyte itself synthesizes and secretes the HA involved in the enlargement of the perivitelline space.
PubMed: 29662352
DOI: 10.1007/s12522-010-0067-0 -
European Journal of Obstetrics,... Dec 2018To investigate the effect of perivitelline space (PVS) abnormalities on the outcomes of intracytoplasmic sperm injection (ICSI) cycles in which the entire cohort was...
OBJECTIVE(S)
To investigate the effect of perivitelline space (PVS) abnormalities on the outcomes of intracytoplasmic sperm injection (ICSI) cycles in which the entire cohort was affected.
STUDY DESIGN
Data from 9752 oocytes obtained from 1151 ICSI cycles performed from June/2010 to August/2016 in a private university-affiliated IVF centre. Cycles were divided into four groups according to the presence or absence of PVS abnormalities: PVS-L group (cycles with the entire oocyte cohort affected by large PVS, n = 265), PVS-G group (cycles with the entire oocyte cohort affected by PVS granularity, n = 280), PVS-L + PVS-G group (cycles with the entire oocyte cohort affected by PVS-L and PVS-G, n = 204), and control group (cycles with the entire oocyte cohort free of PVS abnormalities, n = 402). The effect of PVS abnormalities on ICSI outcomes was assessed by GLM adjusted for potential confounders.
RESULTS
Groups with PVS abnormalities presented substantially higher FSH/follicle (p < 0.001) and FSH/oocyte (p < 0.001) ratios, and lower numbers of follicles (p < 0.001), oocytes (p < 0.001) and embryos (p = 0.002) compared to the control group. PVS-L + PVS-G implantation (p = 0.044) and pregnancy (p = 0.004) rates were significantly lower than in cycles with isolated PVS abnormalities and controls.
CONCLUSION(S)
Cycles in which the entire oocyte cohort is affected by both large PVS and PVS granularity have compromised implantation and pregnancy rates.
Topics: Adult; Female; Humans; Oocytes; Pregnancy; Pregnancy Outcome; Pregnancy Rate; Sperm Injections, Intracytoplasmic
PubMed: 30439650
DOI: 10.1016/j.ejogrb.2018.10.053 -
Microscopy Research and Technique Jul 2003The perivitelline space of mammalian oocytes changes in size and composition during preimplantation development. Often overlooked in the past, this space contains a...
The perivitelline space of mammalian oocytes changes in size and composition during preimplantation development. Often overlooked in the past, this space contains a hyaluronan-rich extracellular matrix prior to fertilization and a cortical granule envelope following release of the cortical granules at fertilization. The hyaluronan-containing matrix of unfertilized oocytes is well developed in some species such as opossums and humans but is scant in rodents including the hamster and mouse. The significance of the hyaluronan-rich matrix, which attaches to the plasma membrane of the oocytes, is not fully understood. However, hyaluronan, which can inhibit membrane fusion, is present in the perivitelline space (PVS) of unfertilized oocytes and must be negotiated by the fertilizing sperm. Following fertilization, the cortical granule envelope forms as the cortical granules disperse, thereby causing the PVS to increase significantly in size. Calcium is important in the dispersion of the cortical granules following exocytosis. Once formed, the cortical granule envelope in some species is about the same thickness as the zona pellucida, but it is not readily visualized unless it is stained with fluorescent probes or examined ultrastructurally after following stabilization with ruthenium red. The envelope contains proteins that remain in the PVS until the time of blastocyst hatching. Although little work has been done on the functions of the cortical granule envelope, several studies are consistent with the idea that it plays a role in blocking polyspermy. While nicotine increases polyspermy in sea urchins, its effects on polyspermy in human smokers have not been characterized, but could be addressed in human in vitro fertilization labs.
Topics: Animals; Cricetinae; Cytoplasmic Granules; Exocytosis; Female; Fertilization; Humans; Male; Microscopy, Confocal; Microscopy, Electron; Oocytes; Sperm-Ovum Interactions; Zona Pellucida
PubMed: 12811740
DOI: 10.1002/jemt.10348 -
JBRA Assisted Reproduction Aug 2023To evaluate the origin and ultrastructure of the coarse granules in the perivitelline space (PVS) of oocytes of a group of couples attending assisted reproduction...
OBJECTIVE
To evaluate the origin and ultrastructure of the coarse granules in the perivitelline space (PVS) of oocytes of a group of couples attending assisted reproduction treatment.
METHODS
The ultrastructure of five oocytes with coarse granulues in the PVS obtained from three patients were evaluated by transmission electron microscopy (TEM). The influence of the ovulation induction regimen on the formation of granules in the PVS of the oocytes of 214 couples and the developmental capacity of these oocytes presenting granules in the PVS was analyzed retrospectively.
RESULTS
In TEM analysis, the microvilli structure was irregular, short, and loosely scattered through the oolemma in the oocytes presenting coarse granules in the PVS. Furthermore, dense lipid droplets were identified within the PVS and the surrounding cumulus cells. In retrospective analysis, the number of oocytes with coarse granules in the PVS was positively correlated with the duration of antagonist administration (r=0.23, p=0.013). Regardless of the type of granule, the presence of coarse or moderately coarse granules in the PVS was positively correlated with low-quality embryos on D3 (r=0.29, p=0.005) and the total number of arrested embryos up to D3 (r=0.33, p<0.001). Furthermore, the presence of coarse granules in the PVS severely exacerbated miscarriage rates.
CONCLUSIONS
Our findings suggest that the presence of especially coarse granules in the PVS is correlated with the reduction of further embryonic developmental capacity in post-implantation stages of embryonic development, indicating a negative impact from aggressive ovulation induction protocols on developing oocytes.
PubMed: 37579275
DOI: 10.5935/1518-0557.20230032 -
Reproductive Biomedicine Online Dec 2017Time-lapse imaging of the human preimplantation embryo in vitro has revealed a transient phenomenon involving the appearance of perivitelline threads, commonly observed...
Time-lapse imaging of the human preimplantation embryo in vitro has revealed a transient phenomenon involving the appearance of perivitelline threads, commonly observed at the two-cell stage. These threads span the perivitelline space, arising at the specific area where the cytoplasmic membrane contacts the zona pellucida, before any perivitelline space is formed. The threads persist as the cytoplasmic membrane retracts from the zona pellucida to form the first cleavage furrow. In this observational report, these structures and their incidence are described. A total of 834 time-lapse videos from IVF treatment cycles, one per patient, were retrospectively analysed for perivitelline threads, from pronuclear formation until completion of the first cell cycle. Threads were observed in 56.4% (470/834) of embryos and varied from a single to an array spanning an area of the zona pellcida. A total of 91.9% (432/470) were seen to form after cytoplasmic membrane-zona-pellucida contact. A total of 76.4% (359/470) were visible at the first cleavage furrow; 77% (362/470) were associated with cytoplasmic fragments at the two-cell-stage. Presence or absence of threads did not affect embryo development. This descriptive study is limited; further characterization of these structures is needed to elucidate their potential role in early human embryo development.
Topics: Cleavage Stage, Ovum; Embryo Implantation; Embryo, Mammalian; Embryonic Development; Humans; Microscopy; Ploidies; Retrospective Studies; Time-Lapse Imaging
PubMed: 29074360
DOI: 10.1016/j.rbmo.2017.09.004 -
Human Reproduction (Oxford, England) Dec 1998The significance of the presence of coarse dark granules in the perivitelline space of oocytes has not been studied before. The study included 2288 intact oocytes [2063...
The significance of the presence of coarse dark granules in the perivitelline space of oocytes has not been studied before. The study included 2288 intact oocytes [2063 in metaphase II (MII), 136 in metaphase I (MI), and 89 in germinal vesicle (GV)] retrieved in 206 intracytoplasmic sperm injection cycles stimulated by a long agonist protocol. The incidence of granules varied with oocyte maturity. It was detected in 34.3% and 4% of the MII and MI oocytes respectively, while none of the GV oocytes contained granules. The woman's age, hormonal values (oestradiol and progesterone), human chorionic gonadotrophin/oocyte retrieval interval, number of oocytes retrieved, and oocyte retrieval/injection interval were not related to the percentage of granular oocytes. Moreover, there was no correlation between the percentage of granular oocytes and the fertilization and cleavage rates, pregnancy outcome, as well as the implantation rate. Patients were divided into three groups according to the total human menopausal gonadotrophin (HMG) dose they received. There was a statistically significant difference between the three groups in the percentage of granular oocytes [17.4 +/- 5.2% versus 26.7 +/- 3.2% versus 45.4 +/- 4.2% in the low-dose (< 30 ampoules), intermediate dose (31-45 ampoules), and high-dose (> 45 ampoules) groups respectively]. We conclude that granularity in the perivitelline space is probably a physiological phenomenon related to the maturational events in oocytes and enhanced by exposure to high dosages of HMG.
Topics: Adult; Cytoplasmic Granules; Female; Humans; Insemination, Artificial; Male; Menotropins; Oocytes; Pregnancy; Prospective Studies; Sperm-Ovum Interactions
PubMed: 9886528
DOI: 10.1093/humrep/13.12.3425 -
The Journal of Reproduction and... Oct 2007Although mouse oocytes progressively acquire meiotic competence during their growth in the ovaries, only half of full-grown oocytes can accomplish meiosis. Two types of...
Although mouse oocytes progressively acquire meiotic competence during their growth in the ovaries, only half of full-grown oocytes can accomplish meiosis. Two types of full-grown oocytes have been reported on the basis of their chromatin configuration, the surrounded-nucleolus (SN) type and the non-surrounded-nucleolus (NSN) type. Therefore, full-grown oocytes collected from the ovaries of adult animals comprise a heterogeneous population; some oocytes are meiotically incompetent (NSN-type), and some are competent (SN-type). In the present study, we found that full-grown oocytes could be classified into two groups using the criterion of formation of the perivitelline space (PVS) after culture with 3-isobutyl-1-methylxanthine (IBMX) for 1 h. In oocytes with a PVS, actin-filled processes within zona pellucidae originating from cumulus cells were reduced, while they were rich in oocytes without a PVS, suggesting that a reduction in these processes contributes to PVS formation. PVS formation was highly correlated with meiotic competence and SN-type configuration. The results of this study demonstrate that PVS formation is a useful criterion for easily distinguishing between SN- and NSN-type oocytes, without injury to the cells.
Topics: 1-Methyl-3-isobutylxanthine; Actins; Animals; Cell Nucleus; Cells, Cultured; Chromatin; Female; Meiosis; Mice; Oocytes; Oogenesis; Zona Pellucida
PubMed: 17587772
DOI: 10.1262/jrd.19064 -
Reproduction, Fertility, and Development Jun 2020The objective of this study was to minimise polyspermic penetration by increasing the perivitelline space (PVS) thickness through supplementation of the hyaluronic acid...
The objective of this study was to minimise polyspermic penetration by increasing the perivitelline space (PVS) thickness through supplementation of the hyaluronic acid components glucuronic acid and N-acetyl-d-glucosamine (GlcNAc). Oocytes (n=4690) were supplemented during the first 24h and/or the remainder of maturation (final 16-18h) with 0.01mM glucuronic acid and 0.01mM GlcNAc and then evaluated for PVS thickness, hyaluronic acid, glutathione and glutathione peroxidase concentrations. Fertilised oocytes were evaluated for polyspermic penetration and embryo development. The PVS thickness and amount of hyaluronic acid was significantly (P<0.05) greater in oocytes supplemented with 0.01mM glucuronic acid and 0.01mM GlcNAc during the second part or all of maturation compared with the other treatments. In addition, polyspermic penetration was significantly (P<0.05) less in oocytes supplemented with 0.01mM glucuronic acid and 0.01mM GlcNAc during the second part or all of maturation compared with the other treatments. Supplementing 0.01mM glucuronic acid and GlcNAc during maturation significantly (P<0.05) increased the percentage of cleaved embryos by 48h after IVF and blastocysts formed by 144h after IVF compared those not supplemented. These results indicate that supplementing PVS components during maturation decreases polyspermic penetration by increasing PVS thickness.
Topics: Acetylglucosamine; Animals; Cell Membrane; Female; Fertilization; Glucuronic Acid; Glutathione; Glutathione Peroxidase; Hyaluronic Acid; In Vitro Oocyte Maturation Techniques; Oocytes; Sus scrofa; Zona Pellucida
PubMed: 32586424
DOI: 10.1071/RD20109