Scientists Break Record in Nurturing Lab Grown Embryos for Longest Period

• Researchers grow embryos in the lab for 13 days, a period extending the time of normal implantation in a mother’s womb.
• Implantation was also witnessed, another hallmark milestone in this study.
• Growth was stopped due to 14-day limit extended by the government regulations.

2 groups of scientists from US and UK have grown embryos for 13 days and had to abandon them due to the 14-day legal restriction imposed by the U.S and the UK governments. Implantation into a mother’s womb signifies the successful transition to the next stage in pregnancy when diversification of lineage, the specification of the fate of the cell and gastrulation begin. Scientists have thus far been unable to understand the mystery associated with implantation of an embryo. However, the current research that involves the use of specific in vivo techniques has been successful in growing embryos for 13 days. Till now, the maximum period of growth of embryos in the laboratory has only been 9 days with 7 days being the average.

Researchers Ali Brivanlou lead researcher from Rockefeller University, New York and Magdalena Zernicka from the University of Cambridge, together with their team of researchers grew the embryos in vivo.

Highlights of the Study

The study showed the initial stages of growth of an embryo which will aid in understanding the following:

• Early Stages of Growth of an Embryo: The essential landmarks in the growth of a normal embryo were noted in the lab-grown embryos like expansion of the embryos, lineage segregation, formation of the bi-laminar disc, cavitation in the amniotic and yolk sac and diversification of the trophoblast.
• Identification of Diseases: An understanding of the initial stages of growth will aid in identifying the reason behind developmental problems and diseases at this stage
• Identifying Reasons Behind IVF Failure: Many couples across the world resort to IVF techniques to have a baby. However, large proportion of the times, the technique fails as the embryo does not get implanted in the mother’s womb. Identifying the key factors associated with implantation will aid in improving the chances of success in an IVF.
• Early Human Pregnancy Loss or Miscarriage: The study provides insights into the growth and development of embryos in the initial stages which can be used to understand and identify problems that lead to termination of early pregnancy.
• Stem Cell Therapy: Identifying the stages and the process involved inthe growth and differentiation of cells into different cell lineages is useful for further studies of stem cell and cell replacement therapies.

The study raises hope for scientists across the world about prospective benefits of this landmark research. However, there are mounting calls from International research bodies to revoke the 14-day ban in the growth of embryos.

Call for Revoke in Ban

The law to allow scientific research on embryos for only 14 days was passed in Britain nearly 30 years ago. Embryos that were discarded from artificial reproductive procedures were allowed to be used for scientific research purposes for 14 days. The time duration was fixed after religious heads and certain governing bodies considered study on human embryos unethical.

Advertisement

The latest study that has demonstrated the ability of the scientific community to grow cells for longer periods, probably longer than 14 days, has raised serious debates about increasing the time of study of embryos. Many scientists now want the ban revoked to promote research and aid in improving treatment for certain diseases.

Three researchers Amy Wilkerson from Rockefeller University, Insoo Hyun from Case Western Reserve University and Josephine Johnston from the Hastings Centre in New York have written in The Journal Nature for this ban to be revisited. When revisiting the ban, these three scientists want discussions to be held with local cultural and religious bodies for a more inclusive law. They wrote “The kind of international discourse we envision could facilitate and inform local decisions to amend law or research policy,”

Advertisement

Technological advancements have triggered a re-think of the law as scientists argue about the huge benefits to human society if details about the early stages of pregnancy are studied. However, Magdalena Zernicka, who was part of the study from the University of Cambridge says “To be able to culture embryos for a couple of days longer would provide an enormous body of information, but it’s not for us now to decide whether we should do it or not. Rules are very useful, we would always adhere to them, and they should be set out by the wider community,”

Studies on Mouse and Human Embryos

Most studies on early embryos were performed on mouse models, but this study brings to the fore the significance of studying embryos from humans. There are differences in cell types and growth characteristics, underlying the importance of studying human embryos for better treatment modalities in cell therapies and understanding miscarriages.

In this latest study on human embryos, an attachment substrate was provided for the growth of the embryos which did not require maternal inputs during the period of growth.

The study has provided

• Insight into the growth potential of human embryos in vivo.
• Prospects for research on various diseases and illnesses.
• Fresh perspective into cell replacement therapies.
• Room for a discussion on the legal limit of 14 days for growing embryos in the laboratory.

Reference:

1. Alessia Deglincerti, Gist F. Croft, Lauren N. Pietila, Magdalena Zernicka-Goetz, Eric D. Siggia& Ali H. Brivanlou “Self-organization of the in vitro attached human embryo”, Nature (2016)

Source-Medindia