皮肤如何维持正常功能

All organs in our body rely on stem cells in order to maintain their function. The skin is our largest organ and forms a shield against the environment. New research results from BRIC, University of Copenhagen and Cambridge University, challenge current stem cell models and explains how the skin is maintained throughout life. The results have just been published in the journal Cell Stem Cell.   New knowledge challenge stem cell models   The skin consists of many different cell types, including hair cells, fat- and sweat glands¹. It protects us against microbial and chemical attacks and forms a waterproof² barrier that prevents fluid loss. Associate professor Kim Jensen' group from BRIC have through mapping of stem cell's behaviour in the skin found out that the skin uses a unique method to renew itself. Their results challenge the current perception of how our skin is renewed.   "Until now, the belief was that the skin's stem cells were organized in a strict hierarchy³（层级） with a primitive⁴ stem cell type at the top of the hierarchy, and that this cell gave rise to all other cell types of the skin. However, our results show that there are differentiated⁵ levels of stem cells and that it is their close micro-environment that determines whether they make hair follicles（毛囊）, fat- or sweat glands, says Kim Jensen.   The new research from Kim Jensen completes the stem cell puzzle.   "Our data completes what is already known about the skin and its maintenance. Researchers have until now tried to fit their results into the old model for skin maintenance. However, the results give much more meaning when we relate them to the new model that our research proposes, says Kim Jensen.   One such example is that it explains the current mystery of how skin cells can divide too much and initiate⁶ a skin cancer, without any traces of genetic⁷ change in the stem cells believed to maintain the outer layer of the skin. The research from the Jensen group may suggest that the reason that no changes can be found is, that these cells do not take part in the over-proliferation at all.