SAN DIEGO, Feb. 9 Fluctuations in vitamin D3 levels control the body's innate immune response, affecting a skin wound's ability to heal, say U.S. researchers.Several unexpected associations between fluctuations of the body's vitamin D3 and infectious disease have emerged in recent investigations, according to Dr. Richard Gallo of the University of California-San Diego School of Medicine and Veterans Affairs San Diego Healthcare System.Gallo's lab discovered that an antimicrobial peptide called cathelicidin is produced by wounds and is necessary to fight infections.The team has discovered that injury stimulates skin cells called keratinocytes, which surround the wound, to increase the production of vitamin D3 and that this in turn increases the expression of genes -- CD14 and TLR2 -- that detect microbes. These genes, together with active vitamin D3, called 1,25D3, then lead to more cathelicidin. In both mice and humans, a deficiency in cathelicidin allows infections to develop more readily.Our study shows that skin wounds need vitamin D3 to protect against infection and begin the normal repair process, said Gallo. The study is published online in advance of publication in the March issue of the Journal of Clinical Investigation.Copyright 2007 by UPI
