Scientists developed monkey specimens grown outside the womb, becoming the oldest primate embryos at 25 days old.

A Closer Look at Lab-Grown Embryo

Independent teams conducted two separate studies that focused on monkey embryo development. By cultivating monkey embryos in the laboratory, scientists can watch the formation of their organs and the development of their nervous system, which are hard to observe while they grow inside the uterus.

Developmental biologist Hongmei Wang worked with her team at the Chinese Academy of Sciences (CAS) to establish a three-dimensional prolonged in vitro culture system to support the embryonic development of cultured monkeys. Egg cells from the female cynomolgus monkey or the crab-eating macaque (Macaca fascicularis) were obtained and fertilized in the laboratory. After a week, the cynomolgus blastocysts were placed in a gel-like substance in cylindrical containers and were observed for 25 days.

Two weeks post-fertilization, the embryos showed genetic features similar to those observed in natural monkeys within the same time frame. By day 20, a neural plate had developed, considered the early indication of the nervous system. According to Wang, their study can help understand early embryo development in primates.

In the second study, developmental biologist Tao Tan and his team at Kunming University of Science and Technology also generated cynomolgus blastocysts but used two different cell culture methods. Their method aims to provide stronger support for the embryos with glucose as an energy source as they grow.

Taking a closer look at the embryos, Tan and his colleagues discovered that the mesoderm cells had developed into heart muscle cells and cells in the lining of blood vessels. There were also signs of developing blood cells and their component in the yolk sac.

The outcomes of these studies provide an important step in designing methods for sustaining embryos outside the womb for longer periods of time. But experts believe the technology will still go a long way before developing an embryo that looks and behaves like the naturally-grown one.

READ ALSO: Scientists Make Mouse Embryo From Stem Cells, Paving the Way to Mammalian Development Process


The Process of Ex Vivo Fertilization

Implantation is a significant event in the fetal development of mammals. In this stage, an exchange connection is established between the embryo and the mother's tissues. Because of the signaling pathways needed in this process, experts are limited by the inaccessibility of the implantation event. As a result, the cellular mechanism of the blastocyst remains a mystery.

Through technological advances in genetics, ex vivo culture provides an environment where scientists can monitor, measure, and control the development of embryos. In this procedure, a tissue undergoes experimentation in an artificial environment outside the organism while maintaining minimum modification of natural conditions.

Ex vivo is not synonymous with in vitro because the tissue or cells need not be in the culture. Unlike in vivo experiments, the ex vivo process allows research investigations under more controlled conditions at the expense of modifying the natural environment.

 

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