Oocytes affected by smooth endoplasmic reticulum aggregates: to discard or not to discard?

Abstract

These results are encouraging and might contribute in the future to a revision of the Alpha-ESHRE Consensus. Larger studies, including a correlation between frequency and size of SERa, clinical outcomes and malformation rates, as well as the follow-up of babies born are nevertheless necessary. In the meantime, the currently conflicting data requires caution when considering transfers of embryos affected by SERa.

Freeze/thaw stress induces organelle remodeling and membrane recycling in cryopreserved human mature oocytes

“…Thus, disturbances in morphology and function of these organelle associations may lead to a reduced oocyte competence for fertilization. In this regard, the presence of very large M-SER aggregates, sometimes related to gonadotropin hyperstimulation [21], has been generally associated with compromised embryo development and implantation [39,40], even though different opinions have been recently expressed [41][42][43]. On the contrary, underdeveloped M-SER aggregates have been found in a percentage of human mature oocytes subjected to vitrification [15] or to a slow freezing protocol based on the use of ethylene glycol as cryoprotectant agent [14], whereas other studies on slow-frozen oocytes treated with propanediol (PrOH) did not evidence qualitatively detectable ultrastructural alterations in M-SER aggregates [12,13,17].…”

The impact of letrozole administration on oocyte morphology in breast cancer patients undergoing fertility preservation

“…Although the presence of granular vacuoles in oocytes was associated with a higher rate of female karyotype abnormalities, the transfer of embryos derived from oocytes with granular vacuoles was associated with higher abortion rates and poor clinical outcomes ( Sousa et al ., 2016 ). Among intracytoplasmic dimorphisms, smooth endoplasmic reticulum aggregates were considered the most severe abnormality of MII oocytes due the reported outcomes, such as reduced fertilization and clinical pregnancy rates, early fetal demise and imprinting disorders in newborns ( Rienzi et al ., 2011 ; 2012 ; Shaw-Jackson et al ., 2016 ). These aggregates can be identified as translucent vacuole-like structures in the cytoplasm by phase contrast microscopy ( Alpha Scientists in Reproductive Medicine & ESHRE Special Interest Group of Embryology, 2011 ; Shaw-Jackson et al ., 2016 ).…”

“…Among intracytoplasmic dimorphisms, smooth endoplasmic reticulum aggregates are the most severe abnormality of MII oocytes ( Rienzi et al ., 2011 ; 2012; Shaw-Jackson et al ., 2016 ). In the control group, there was smooth endoplasmic reticulum in 2.5% of retrieved oocytes, versus 0.1% in the letrozole group.…”

“…In the control group, there was smooth endoplasmic reticulum in 2.5% of retrieved oocytes, versus 0.1% in the letrozole group. Previous studies recommend that one should not use oocytes with this feature for injection ( Alpha Scientists in Reproductive Medicine & ESHRE Special Interest Group of Embryology, 2011 ; Rienzi et al ., 2011 ; Shaw-Jackson et al ., 2016 ). Nevertheless, studies that are more recent could not find an adverse effect on embryological, clinical or neonatal data for oocytes with smooth endoplasmic reticulum aggregates, since more than 20 children were born from oocytes with this abnormality.…”

“…Nevertheless, studies that are more recent could not find an adverse effect on embryological, clinical or neonatal data for oocytes with smooth endoplasmic reticulum aggregates, since more than 20 children were born from oocytes with this abnormality. Moreover, the exclusion of these oocytes from ICSI cycles causes an increased frequency of transfer cancellation ( Ashrafi et al ., 2015 ; Shaw-Jackson et al ., 2014 ; 2016 ; Restelli et al ., 2015 ).…”