Microribonucleic acids in sperm and spent culture media: a new direction in predictive diagnostics or another disappointment?


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Volume 113, Issue 5, Pages 929–930


Jason Franasiak, M.D., H.C.L.D./A.L.D.


Reflections on "Microribonucleic acids in combined spent culture media and sperm are associated with embryo quality and pregnancy outcome" by Abu-Halima et al.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. 


Go to the profile of Masood
almost 2 years ago

     Thank you Dr. Jason Franasiak for writing a reflection on our manuscript, which we do find it very interesting, mainly to trace the miRNA changes during the human embryonic developmental stages and to relate the identified miRNAs to the embryonic quality and pregnancy outcome, if possible.

     You have acually addressed an important point regarding the changes of small RNAs in the embryo development. However, we would like to point out that the main aim of our study was to identify miRNAs that can be used either to differentiate between grades or to predict pregnancy outcome. The identified miRNAs stem from the day of the embryo transfer i.e. Day 3.  Likely, there may be other miRNAs that can be identified form the blastocyst stage as indicated recently by many colleagues. Deciding whether to have a day three or day five embryo transfer is a hotly debated topic. Usually, it’s a decision made by the clinic’s embryologists and other doctors, who advise the patients as to why they believe it’s the best course of action. In our study, we have decided to include only a day three embryos as most of our collected samples were on Day 3 embryo transfer.

    To follow the fate of the miRNA changes during the human embryonic developmental stages and to relate the identified miRNAs to the embryonic quality and the pregnancy outcome would be a very interesting point to research.

     As for the second part of the comment, regarding the single embryo transfer procedure, I would like to point out that the included spent culture media samples were collected from a center in Bethlehem, Palestine, as indicated in the ‘’Materials and Methods’’ section. In the Middle East, specifically in Palestine, couples prefer to have as many babies as possible, and therefore, clinicians and couples preferred more than one embryo to be transferred. This is because if three embryos are transferred, one, two, three or none of them may implant! On the contrary, couples in Europe and/or USA, prefer only one embryo to be transferred even if more are available!.

     In our experimental work, and to reduce the bias of sample pooling, we considered only couples with three G1-embryos transfers, each (see also Figure 1, in the article).  The very small amount of RNA in this sample type requires the pooling of analyzed spent culture media samples.

Thanks again your comments