Predictive value of oocyte morphology in human IVF: a systematic review of the literature (original) (raw)
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Relevance and Methodology for the Morphological Analysis of Oocyte Quality in IVF and ICSI
Journal of Reproductive Biotechnology and Fertility, 2011
Oocytes collected from patients following ovarian stimulation exhibit varying qualities. The quality of oocytes has an effect on its subsequent fertilization, developmental competence postfertilization and the viability of resultant embryos. The aim of this article was to review the morphological criteria devised for assessment of oocyte quality by ordinary light and polarized light microscopy before IVF or ICSI. The parameters employed in the evaluation of oocyte morphology include the appearance of: structure of the cumulus-oocyte complex, oocyte cytoplasm, perivitelline space, zona pellucida, polar body and meiotic spindle. The authors have nothing to declare.
Morphology of in-vitro matured oocytes: impact on fertility potential and embryo quality
Human Reproduction, 2001
BACKGROUND: The purpose of the present study was to investigate the morphology of in-vitro matured metaphase II (MII) oocytes and to observe if there was a difference in the morphology between polycystic and normal ovaries. Furthermore, the morphology of in-vitro matured MII oocytes was related to their subsequent fertilization and cleavage rates and to embryo quality. METHODS: This retrospective study included 264 MII oocytes obtained in 100 consecutive cycles. Oocyte retrieval was performed transvaginally and cumulus enclosed oocytes were matured for 28-30 h before evaluation. Prior to ICSI, all MII oocytes were graded into three groups according to the number of anomalies: grade I: oocytes without any anomaly (n ⍧ 144, 54%), grade II: oocytes with one anomaly (n ⍧ 87, 33%) and grade III: oocytes with at least two anomalies (n ⍧ 33, 12.5%). RESULTS: Oocyte grades did not differ between women with polycystic ovaries [grades I, II and III respectively: 58/94 (61.7%), 29/94 (30.9%) and 7/94 (7.4%)] and women with normal ovaries [grades I, II and III respectively: 86/170 (50.6%); 58/170 (34%); 26/170 (15.3%)]. Morphology was not related to fertilization rates. The cleavage rate was, however, affected by morphological anomalies (grade I [77/144 (53.5%) versus grade II 33/87 (37.9%) (P ⍧ 0.03)], although no significant decrease in cleavage rate could be demonstrated when all grade II and III oocytes were compared with normal oocytes. Significantly more embryos of good quality developed after grade I oocytes [54/144 (37.5%)] compared with those from grade II and grade III oocytes (22/120; P ⍧ 0.001). The presence of cytoplasmic abnormalities significantly decreased the cleavage rate (P ⍧ 0.04) and also the number of good quality embryos (P < 0.001). CONCLUSION: The in-vitro maturation of oocytes without anomalies yields higher quality embryos, with higher cleavage rates, than those with anomalies.
Ultrastructure of human oocytes after in vitro maturation
Molecular Human Reproduction, 2015
study hypothesis: How does the ultrastructure of human oocytes matured in vitro compare with oocytes collected from women after full hormonal stimulation? study finding: The ultrastructure of human oocytes matured in vitro is largely, but not entirely, similar to those matured in vivo. what is known already: Embryos derived from in vitro-matured oocytes often have limited developmental potential, possibly as an effect of inappropriate in vitro maturation (IVM) conditions. Transmission electron microscopy (TEM) is a valuable research tool to compare in vivo and in vitro matured oocytes. However, previous studies on the ultrastructure of human IVM oocytes were done with inadequate material or inappropriate IVM conditions, and have limited significance. study design, samples/materials, methods: Immature cumulus cell-enclosed oocytes, retrieved from mid-sized antral follicles of women requiring IVM treatment, were matured in vitro for 30 h. No leftover germinal vesicle-stage oocytes collected from fully stimulated cycles were used. Control in vivo matured oocytes were obtained from age-matched women undergoing full ovarian stimulation. In vitro and in vivo matured oocytes were analysed by TEM and compared according to previously established morphometric criteria of oocyte quality. main results and the role of chance: All oocytes had normal ooplasm showing uniform distribution of organelles. Mitochondrial morphology appeared similar between the maturation conditions. Cortical granules were found typically stratified in a single, mostly continuous row just beneath the ooplasm in all oocytes. Microvilli were well preserved after IVM. Vacuoles were only occasionally found in all oocytes and, if present, they were frequently associated with lysosomes. Mitochondria-smooth endoplasmic reticulum (M-SER) aggregates and mitochondria-vesicles (MV) complexes were commonly found in in vivo matured oocytes. However, large MV complexes partially replaced M-SER aggregates in IVM oocytes. limitations, reasons for caution: As a note of caution it should be noticed that, being laborious and technically demanding, TEM cannot be applied to a large number of samples in a single investigation. Therefore, our data require further independent confirmation. wider implications of the findings: Our data suggests the notion that TEM remains a valuable research tool that can also offer quantitative data if associated with morphometric criteria of evaluation. Therefore, it can be adopted to test pre-clinically the performance of novel in vitro systems that are demanded to make oocytes IVM more successful in the human. large scale data: Not applicable. study funding and competing interest(s): This study was independently funded by Biogenesi Reproductive Medicine Centre, Monza, Italy. All authors declare that their participation in the study did not involve factual or potential conflicts of interests.
Ultrastructure of in vitro Matured Human Oocytes
Iranian Red Crescent Medical Journal, 2013
Background: Approximately 20% of recovered oocytes are immature and discarded in intracytoplasmic sperm injection (ICSI) procedures. These oocytes represent a potential resource for both clinical and basic science application. Objective: The aim of this study was to evaluate the ultrastructure architecture of in vitro matured human oocytes using transmission electron microscopy (TEM).
Morphology and Aneuploidy of in vitro Matured (IVM) Human Oocytes
Aneuploidy in Health and Disease, 2012
The first visible sign of meiosis resumption is a gradual germinal vesicle breakdown (GVBD). The nuclear envelope disintegrates while the chromosomes remain at their position (Motlik & Fulka, 1976). In vitro, GVBD starts in less than 6 hours after the removal of the oocyte from the ovary (Combelles et al., 2002), presuming that the oocyte has already reached its final size before the establishment of in vitro conditions (Mrazek & Fulka, 2003). The GVBD phase itself lasts for approximately 12 hours (Angell, 1995). 2.1.2 Cytoskeleton GV oocytes possess a dense sub-cortical microtubular network that is characteristic of interphase cells (Combelles et al., 2002). At the onset of GVBD, microtubules begin to www.intechopen.com Morphology and Aneuploidy of in vitro Matured (IVM) Human Oocytes 165 assemble in the centrosomes (which contain microtubules organizing centers-MTOCs) as small star-like structures called asters, whereas there are no free microtubules in the cytoplasm. Later, the microtubules elongate and asters migrate towards opposite poles forming a barrel-like structure called meiotic spindle. The highly condensed chromosomes attach to the microtubules at their centromeric regions and align in the metaphase equatorial plane between both poles of the meiotic spindle (Battaglia et al., 1996). In the first anaphase, chromosomes move toward the poles of the meiotic spindle located at the animal pole of the oocyte (Matsuura & Chiba, 2004). In the next phase, namely the first telophase microtubules can be observed as very dense network of threads spreading between the chromatin of the oocyte and its first polar body (PB1). Actin filaments, also called microfilaments, regulate various dynamic processes during oocyte maturation. Although they are not directly involved in GVBD and meiotic spindle formation, they play a key role in rearrangement of cell organelles and cell polarization (Albertini et al., 2003). They are also responsible for the positioning of the meiotic spindle, movement and separation of chromosomes and extrusion of the PB1 (Kim et al., 1998; Sun & Schatten, 2006). 2.1.3 Cell organelles Growth of an oocyte is also characterized by redistribution of cell organelles into a subcortical region beneath the cell membrane, whereas during the maturation phase they are distributed more centrally (Albertini et al., 2003). The only exceptions are the cortical granules which are translocated from the smooth endoplasmic reticulum towards the periphery of the oocyte by the microfilaments and are distributed immediately beneath the plasma membrane in the fully grown mature oocyte (Sun et al., 2001).
Iranian Journal of …, 2011
Background: In general, 15% of oocytes collected in ART cycles are immature. These oocytes may be cryopreserved further for use in in-vitro maturation (IVM) program. Objective: The aim of this study was to determine maturation capacity, morphometric parameters and morphology of human immature oocytes in both fresh IVM (fIVM) and vitrified-IVM (vIVM) oocytes. Materials and Methods: 93 women who underwent controlled ovarian stimulation for ART were included. The immature oocytes (n=203) were divided into two groups: the first group (n=101) directly matured in vitro; and the second group (n=102) first vitrified, then matured in vitro. All oocytes underwent IVM in Ham's F10 supplemented with LH+FSH and human follicular fluid. After 48h of incubation, the oocyte maturation rates, as well as morphometric and morphologic characteristics were assessed using cornus imaging and were compared. Results: Oocyte maturation rates were reduced in vIVM, (40.4%), in comparison with fIVM (59.4%, p<0.001). Following morphometric assessment, there was no difference in the mean oocyte diameters (µm) between fIVM and vIVM, 156.3±6.8 and 154.07±9.9, respectively. Other parameters of perimeters, egg areas, as well as oocyte and ooplasm volumes were similar in two groups. In addition, more morphologic abnormalities, such as, vacuole, and dark oocyte were observed in vIVM oocytes. Conclusion: fIVM was more successful than vIVM groups. No statistical differences were noticed in morphometry assessment in two groups. This suggests that morphometric parameters can not be applied as prognosis factor in oocyte maturation outcome in IVM program.
A Quantitative and Morphological Analysis of Oocytes Collected During 438 IVF Cycles
Journal of Assisted Reproduction and Genetics, 2000
Purpose: Our purpose was to determine if the number ofretrieved oocytes, oocyte maturity, morphology, and otherembryological parameters are related to the outcome oftreatment. Methods: This retrospective study on 438 IVF cyclesanalyzes the numbers of retrieved oocytes, fractured zonaoocytes, germinal vesicle-stage oocytes, normally andabnormally fertilized oocytes, pregnancy rate, age of femalepartner, ovarian stimulation protocol, day of hCG injection,and serum estradiol concentration. Results: (1) Pregnancy rate increases with an increase inthe number of retrieved oocytes, (2) a high incidence offractured zona pellucida oocytes has a negative effect onfertilization rate but none on pregnancy rate, (3) a highincidence of immature oocytes is associated with improvedfertilization and pregnancy rates, and (4) an inverserelationship between the presence of immature oocytes and oocyteswith fractured zona pellucida is suggested. Conclusions: Precise oocyte assessment in IVF cyclesprovides informations useful for the analysis and improvementof ovarian stimulation protocols.
Ultrastructural aspects of human immature oocytes
Romanian …, 2010
In vitro fertilization, one of assisted reproductions technique is, for some couples, the only possibility to conceive a child. One of the main condition that must be fulfield in order to reach this goal is the quality of human oocytes.
Archives of Gynecology and Obstetrics, 2015
Purpose Recently, the upgrading of in vitro maturation (IVM) of human oocytes as a promising strategy has emerged in assisted reproductive technology (ART). The goal was to evaluate the correlation of the in vitro matured oocytes selected on the basis of the zona pellucida (ZP) birefringence and meiotic spindles (MS) detection with fertilization and subsequent embryo development in ICSI program. Methods A total of 168 immature oocytes [germinal vesicle (n = 140) and metaphase I (n = 28)] obtained from patients undergoing oocytes retrieval for ICSI. After in vitro culture for 24-40 h, 112 (67 %) oocytes reached to MII stage. Using a polarized microscopy, the presence of MS and ZP birefringence were assessed in matured oocytes, followed by ICSI performance. Results The rates of fertilization in oocytes with spindles (51.3 %) were similar to that of the oocytes without spindles (50.7 %; P = 1.00). Moreover, the fertilization rates in high birefringence (HB) oocytes was not statistically different than oocytes with low birefringence (LB) (P = 0.44). The findings also showed that 64.9 % of the fertilized oocytes developed to embryos, in which 33.3 % were derived from spindle-detected oocytes. Regarding the ZP birefringence, 35.5 % of the embryos were derived from HB oocytes. Conclusions There were insignificant relationships between the MS detection and ZP birefringence score with the rates of fertilization and embryo development in IVM oocytes.