Rat Hair Follicles Contain Adult Stem Cells
According to a United Press International story printed in Physorg.com News
, cells inside whisker follicles of rats have been shown by Swiss researchers to be adult stem cells. When a hair or whisker in mammals wears out, cells inside the follicle differentiate to grow a new one. In this study, the researchers isolated and cultured cells from the rat hair follicles, then transplanted them into mice skins, where they developed into new follicles. They also expressed genes characteristic of stem cells.
This article has appeared on several on-line sources. The original research appears in the on-line edition of the National Academy of Sciences and is only available by subscription, but the abstract
has some additional interesting points: the stem cells generated all the follicles and the sebaceous gland; several stem cells formed a hair bulb; and there are many more stem cells in hair follicles than had been anticipated.
The abstract, being an abstract, does not talk about any mutations that occurred in the stem cells while in culture, nor does it present any theories about the mechanisms for these actions. I am myself curious to know whether the mice grew mouse hair or rat hair. This may sound like a flippant question, but in cross-species transplantation it is an important one. If the mice grew mouse hair, the stem cells are even more plastic or pluripotent than if they grew rat hair, which would mean they retained their rat DNA instructions. Hans Spemann, in his early embryology experiments, transplanted one part of an embryo to another and won a Nobel Prize for his work on the “organizing principle” of embryos. Sometimes when he took what would become a tail on one embryo and grafted it to the location that would be a head on anther embryo, it developed as a head and not a tail, which means it was not operating on only its own instructions. Under what conditions might stem cells do the same thing?