Reacción a "Reactions to study revealing how oocytes survive toxic protein aggregates for decades"

Among the fertility problems we face in assisted reproduction units, there are 20% of cases in which no apparent reason can be found, which is why we call it sterility of unknown origin. These cases frequently cause problems in achieving pregnancy even when we use techniques such as in vitro fertilisation and transfer embryos with the correct genetic load into the mother's uterus. 

This is due to the fact that the genetic load of the embryo is as important as its cytoplasm and we must take into account that the embryo shares the cytoplasm of the oocyte, especially during the first days of development. 

From a reproductive point of view, this article is very interesting as it demonstrates how the presence of certain protein aggregates in the cytoplasm of the oocytes can cause poor oocyte quality and embryos with a low probability of becoming pregnant, even if they have a correct genetic load. 

These protein aggregates have a toxic effect, widely studied in this and other studies, which the egg may have difficulty in eliminating as they are generally eliminated during the cell divisions that the egg does not begin to carry out until it is fertilised. 

The novelty of this article lies in the discovery by the authors of special structures, which they have named EndoLysosomal Vesicular Assemblies (ELVA), dispersed in the cytoplasm of the oocyte in a number of approximately 50, capable of localising and inactivating these protein aggregates, rendering them harmless. 

This inactivation occurs just as the egg completes its maturation process prior to fertilisation by the sperm. ELVAs would act as a cleaning team, eliminating these deleterious effects on the egg, keeping its cytoplasm in optimal conditions for successful fertilisation and subsequent development. 

According to the study, the demonstration lies in the fact that if ELVA activity is inhibited, an accumulation of these protein aggregates in the egg cell occurs, damaging the survival and future viability of the embryo. 

On the other hand, it has also been seen how these aggregates can have harmful effects on other long-lived cells with few cell division processes, such as neurons, and could be related to neurodegenerative diseases such as Alzheimer's, so the study of how ELVA behave in this type of cell could help in the research and treatment of other diseases.