Embryos in jelly

Stem cells were "put to sleep" with hydrogel

Oleg Lischuk, N+1 

A team of British and American scientists managed to immerse stem cells in a latent state (stasis) to preserve their properties.

   Embryos in a hydrogel. Image: Canton et al., ACS Central Science, 2016

A team of British and American scientists managed to immerse stem cells in a latent state (stasis) to preserve their properties. The idea of the development was prompted by the peculiarity of the course of pregnancy in some animals, according to a publication in the journal ACS Central Science (Mucin-Inspired Thermoresponsive Synthetic Hydrogels Induce Stasis in Human Pluripotent Stem Cells and Human Embryos).

Embryonic and induced pluripotent stem cells are capable of developing into almost any kind of cells in the body. This is their property that underlies various types of experimental cell therapy and tissue engineering. However, in culture, stem cells rapidly proliferate and differentiate, losing their versatility.

The researchers of the University of Sheffield and the University of Louisville in Kentucky used in their work the results of studying diapause — the ability of some mammals (for example, kangaroos) to postpone the development of the embryo in the early stages of development before the onset of favorable food and climatic conditions. During diapause, an embryo consisting of a small number of identical cells is located in the uterus in a shell of mucin glycoprotein and does not develop.

The search for a synthetic analogue of mucin led scientists to create a soft hydrogel from a copolymer of polyglycerine monomethacrylate-poly-2-hydroxypropyl methacrylate (PGMA55-PHPMA135). This material, rich, like mucin, in hydroxyl groups, retains a jelly-like consistency at body or incubator temperature, and when cooled becomes liquid, without interfering with the extraction of cells.

Molecular structure of mucin and PGMA55-PHPMA135 (left), 
stem cells and embryo preserved in hydrogel (right)
Irene Canton, et al., ACS Central Science, 2016

Human pluripotent cells and embryos immersed in hydrogel during the experiment stopped developing in the resting phase of mitosis (G0), in which cells do not divide. The first remained in stasis for at least two weeks, the second — up to eight days. After extraction from the hydrogel, their proliferation continued in the usual way.

The researchers note that in addition to chemical factors, cells are also able to perceive physical stimuli, including stiffness and contractility, through complex feedbacks. This, apparently, is the basis of their immersion in stasis in mucin and hydrogel. The development can significantly simplify and reduce the cost of storage and transportation of stem cells and embryos.

Portal "Eternal youth" http://vechnayamolodost.ru 12.02.2015