Friday, May 6, 2016

First in vitro culture of Human embryos through implantation stage (13 days).

Developmental biologist could grow the human embryos in the lab up to 9 days till now, but according to a recent paper published in Nature and Nature cell biology they have grown human embryos in the lab up to 13 days’ post fertilization. 

The technique has already made it possible for the scientist to visualize features never seen before in human embryos or to know the reasons behind early pregnancy loss.

The authors reported that it was fascinating to watch as the human embryos derived from IVF self-organized themselves in the absence of maternal tissue in a petri dish eventually differentiating into founding cell lineage of the fetus and its supporting tissue.  

This is the first glimpse of beginning of human life at a time when it usually implants itself into the endometrium making it impossible to visualize.

An improved culture medium of gel matrix with higher level of oxygen seems to be the key towards this advancement.

Marta Shahbazi, a researcher at Britain's University of Cambridge who was part of the research teams quoted "Embryo development is an extremely complex process and while our system may not be able to fully reproduce every aspect of this process, it has allowed us to reveal a remarkable self-organizing capacity ... that was previously unknown."

The recent achievement has wider implications for scientists and fertility industry around the world. Martin Pera, a stem-cell researcher at the University of Melbourne in Australia said “Studying embryos in vitro could help researchers who are trying to grow stem cells into embryo-like structures to judge the accuracy of their work.”
About 50% of embryos that are implanted in the mother’s womb do not go far in pregnancy and studies of embryos in vitro could give a new insight into the process.

 Norbert Gleicher, head of the Center for Human Reproduction, an IVF clinic in New York City said “The implantation process is a big black box for us clinicians.”

This work could also help the scientists and researchers to understand the role of signaling molecules from extraembryonic tissues for the developing embryo. This in turn could lead to a better understanding of how to induce a human stem cell to grow into cell lines that have therapeutic potential.

The researchers terminated the experiment at 13 days because raising embryos past 14 days or primitive streak formation raises many ethical and policy issues.  At least 12 countries including U.K. prohibit the scientists to work past the 14 days’ limit.  This is also the latest time when an embryo can split into monozygotic twins, and it is also the beginning of an individual existence.

George Daley, a stem-cell researcher at Children’s Hospital Boston in Massachusetts said “Their achievements in the lab may be grounds for re-examining the limit.” Other researchers also agreed that this work raises questions around the 14 days’ limit because if scientist succeed in growing stem cells into embryo-like structures, then will the 14 days’ limit also apply to them?


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