Ultrastructure of tubular smooth endoplasmic reticulum aggregates in human metaphase II oocytes and clinical implications

Sá, Rosália; Cunha, Mariana; Silva, Joaquina; Luís, A.; Oliveira, Cristiano; Silva, José Teixeira da; Barros, Alberto; Sousa, Mário

doi:10.1016/j.fertnstert.2011.04.088

Cited by 78 publications

(64 citation statements)

References 32 publications

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“…Our morphometric/quantitative evaluation strongly confirms this hypothesis and adds a new information: a similar ultrastructural phenomenon occurs in RA. To better comprehend the [37][38][39], thus confirming the pivotal role of SER and associated mitochondria during fertilization and during the first embryo cleavages. A panel of experts strongly recommend that oocytes with this feature should not be inseminated [40], although a different opinion has been recently expressed [41].…”

Section: Ooplasmic Aggregatesmentioning

confidence: 90%

Ultrastructural markers of quality are impaired in human metaphase II aged oocytes: a comparison between reproductive and in vitro aging

Bianchi

Macchiarelli

Micara

et al. 2015

J Assist Reprod Genet

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Section: Ooplasmic Aggregatesmentioning

confidence: 90%

Ultrastructural markers of quality are impaired in human metaphase II aged oocytes: a comparison between reproductive and in vitro aging

Bianchi

Macchiarelli

Micara

et al. 2015

J Assist Reprod Genet

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“…In fact, oocyte cytoplasmic vacuolization that are associated with the presence of damaged mitochondria, ruptures in the oolemma, decreased amount of microvilli, and characteristics of degenerating oocytes have been reported [39]. In addition, vacuoles are rare in mature and good quality oocytes, but may be found in cytoplasmically damaged, early regression, or aging oocytes [40]–[42]. In summary, the significantly decreased outcome, cytoplasmic vacuolization and damaged mitochondria in oocytes with a DZP suggested that the oocyte quality (such as cytoplasmic damage) was correlated with a DZP in IVF/ICSI cycles [6], [38], [40]–[42].…”

Section: Discussionmentioning

confidence: 99%

“…However, damaged mitochondria and significantly increased vacuoles have been reported as signs of cytoplasmic damage in mammalian oocytes [41], [42]. Moreover, oocytes with damaged cytoplasm are associated with decreased oocyte quality, low embryo development potential, and adverse pregnancy outcomes [41]–[45].…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, oocytes with damaged cytoplasm are associated with decreased oocyte quality, low embryo development potential, and adverse pregnancy outcomes [41]–[45]. Thus, on the basis of the decreased rate of good quality embryos, implantation and clinical pregnancy rates in Group B and the ultrastructural analysis of oocytes with a DZP, we proposed that oocytes with a DZP might contain cytoplasmic damage, which may be the underlying reason for the decreased fertilization rate, rather than the denser texture in the DZP, which directly prevents sperm-egg binding [41], [42]. However, a role in the denser texture of the DZP in preventing sperm penetration at fertilization should also not be excluded.…”

Section: Discussionmentioning

confidence: 99%

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Oocytes with a Dark Zona Pellucida Demonstrate Lower Fertilization, Implantation and Clinical Pregnancy Rates in IVF/ICSI Cycles

Shi

et al. 2014

PLoS ONE

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The morphological assessment of oocytes is important for embryologists to identify and select MII oocytes in IVF/ICSI cycles. Dysmorphism of oocytes decreases viability and the developmental potential of oocytes as well as the clinical pregnancy rate. Several reports have suggested that oocytes with a dark zona pellucida (DZP) correlate with the outcome of IVF treatment. However, the effect of DZP on oocyte quality, fertilization, implantation, and pregnancy outcome were not investigated in detail. In this study, a retrospective analysis was performed in 268 infertile patients with fallopian tube obstruction and/or male factor infertility. In 204 of these patients, all oocytes were surrounded by a normal zona pellucida (NZP, control group), whereas 46 patients were found to have part of their retrieved oocytes enclosed by NZP and the other by DZP (Group A). In addition, all oocytes enclosed by DZP were retrieved from 18 patients (Group B). No differences were detected between the control and group A. Compared to the control group, the rates of fertilization, good quality embryos, implantation and clinical pregnancy were significantly decreased in group B. Furthermore, mitochondria in oocytes with a DZP in both of the two study groups (A and B) were severely damaged with several ultrastructural alterations, which were associated with an increased density of the zona pellucida and vacuolization. Briefly, oocytes with a DZP affected the clinical outcome in IVF/ICSI cycles and appeared to contain more ultrastructural alterations. Thus, DZP could be used as a potential selective marker for embryologists during daily laboratory work.

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“…New evidence demonstrates that the Endoplasmic Reticulum (smooth or rough) plays additional crucial roles in stress responses in the oocyte or embryo [19] as well as in the regulation of the meiotic spindle [20]. Different malformations and pathologies have been described after transfer of an embryo originating from a SERa+ oocyte [21,22] but equally when a non affected embryo from the same oocyte cohort is transferred [9,12]. Indeed, some aggregates of smaller size only detectable by electron microscopy could also be pathological [9].…”

Section: Discussionmentioning

confidence: 99%

Policy of IVF centres towards oocytes affected by Smooth Endoplasmic Reticulum aggregates: a multicentre survey study

Beirs

Shaw-Jackson

Rozenberg

et al. 2015

J Assist Reprod Genet

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Purpose The presence of Smooth Endoplasmic Reticulum aggregates (SERa) has been reported to be associated with adverse outcomes. An Alpha-ESHRE Consensus was published in 2011, strongly recommending to not inseminating affected oocytes. On the other hand, healthy babies have been born from oocytes presenting this dysmorphism. We surveyed several European IVF centres, to assess their attitudes concerning affected oocytes. Methods This survey is based on a computer format and includes questions regarding the fate of affected oocytes. Results About 14 % of centres who answered our survey discard SERa+ oocytes. 43 % of centres that do not discard the oocytes, register and follow up neonatal data. About a quarter of centres inform their patients about this dysmorphism. Half of them require an informed consent prior to transferring affected embryos. Twenty-one centres reported having SERa+ births, with one reporting a malformation. 48 % of centres declared having been influenced by the Alpha-ESHRE Consensus, in their management policy of SERa+ oocytes. Conclusions Few centres scrupulously respect the recommendations of the Alpha-ESHRE Consensus and discard affected oocytes. Since it is essential to determine if there truly is an impact of this dysmorphism and whether the guidelines are still valid, transfer of affected embryos should only be done when accompanied with data recording and monitoring of all foetal malformations from IVF. Clarifying the situation will allow IVF centres to correctly inform patients about the risk of birth malformations as well as whether a decreased chance of pregnancy exists.

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Ultrastructure of tubular smooth endoplasmic reticulum aggregates in human metaphase II oocytes and clinical implications

Cited by 78 publications

References 32 publications

Ultrastructural markers of quality are impaired in human metaphase II aged oocytes: a comparison between reproductive and in vitro aging

Ultrastructural markers of quality are impaired in human metaphase II aged oocytes: a comparison between reproductive and in vitro aging

Oocytes with a Dark Zona Pellucida Demonstrate Lower Fertilization, Implantation and Clinical Pregnancy Rates in IVF/ICSI Cycles

Policy of IVF centres towards oocytes affected by Smooth Endoplasmic Reticulum aggregates: a multicentre survey study

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