Researchers at the University of California, San Diego (UCSD) School of Medicine have uncovered a surprising link between the skin bacteria and the body’s ability to control inflammation after injury. The findings, published in Nature Medicine, could open new avenues for treating inflammatory skin conditions such as eczema and psoriasis.
Skin Bacteria and Microbes: Guardians Against Overactive Inflammation
Dr. Richard L. Gallo, professor of medicine and pediatrics at UCSD and chief of dermatology at the Veterans Affairs San Diego Healthcare System, described the study’s main takeaway: “These germs are good for us.” The research, led by postdoctoral fellow Yu Ping Lai, demonstrates how certain skin bacteria, part of the natural microflora, regulate immune responses to prevent excessive inflammation.
The study found that staphylococcal bacteria produce a molecule called lipoteichoic acid (LTA). This molecule interacts with keratinocytes—the primary cells in the outer layer of the skin—to inhibit overly aggressive inflammatory responses. This delicate balance is crucial to healing after injury and maintaining overall skin health.
Linking Skin Science to the “Hygiene Hypothesis”
The findings offer new insights into the “hygiene hypothesis,” a concept introduced in the 1980s suggesting that reduced exposure to microbes in childhood could increase susceptibility to allergies and autoimmune conditions. Gallo noted that the study explains this hypothesis by showing how the skin’s microbiota modulates inflammation.
The researchers explained that when staphylococcal bacteria remain on the skin’s surface, they do not cause inflammation. However, they trigger a controlled inflammatory response when introduced below the surface—such as through a wound. The team also discovered that this regulation involves Toll-like receptor 3 (TLR3), essential for normal inflammation after skin injury.
Paving the Way for New Skin Therapies
“This research reveals elements of the wound repair response that were previously unknown,” Gallo stated. “It may help us devise new therapeutic approaches for inflammatory skin diseases.” Conditions like eczema, psoriasis, and other chronic inflammatory disorders could benefit from treatments inspired by the regulatory mechanisms of the skin’s natural bacteria.
This study underscores the importance of the relationship between humans and their microbiota. Far from being harmful invaders, many bacteria are essential to maintaining health, especially in sensitive systems like the skin. As science unravels these interactions, the potential for new medical breakthroughs becomes increasingly apparent.
Reference: University of California – San Diego. “Some germs are good for you: Surface bacteria maintain skin’s healthy balance.” ScienceDaily. ScienceDaily, 23 November 2009. <www.sciencedaily.com/releases/2009/11/091122161742.htm>.
