To serve and protect
Healthy skin barrier is essential in the fight against disease.
Skin. It’s not only the body’s largest organ, but it also serves as an important barrier to infection and disease. Protecting that barrier from damage and disruption requires a keen awareness of a multitude of molecular and immunological signaling pathways.
According to Jack L. Arbiser, MD, PhD, FAAD, a dermatologist with Metroderm/United Derm Partners in Atlanta, careful attention to maintaining the skin’s barrier function can guard against specific skin conditions such as atopic dermatitis, psoriasis, or other related issues. Dr. Arbiser unraveled the complexities of the skin barrier — the human shield against disease — during yesterday’s session, U039 – Understanding the Skin Barrier.
“The human body is constantly surrounded by a mixture of beneficial and pathogenic bacteria, fungi, and viruses. Given the opportunity, the bacteria will try to invade the body and reach the blood stream,” Dr. Arbiser said. “The skin barrier is both a physical barrier, like a suit of armor, and a chemical barrier. The chemical barrier signals immediately that the barrier has been breached and starts beneficial inflammation. In normal skin, inflammation is decreased when the threat is gone.”
Barrier breach
Research has shown how disruption of the skin barrier can lead to inflammatory disorders, and how an intact skin barrier results in resolution of inflammation, he said. A healthy skin barrier includes proper maintenance of the acid mantle and appropriate levels of ceramides.
“Three factors are required for barrier function,” Dr. Arbiser said. “The first is extracellular acid, which decreases inflammation as well as kills pathogenic staph and strep. Mitochondria are required for optimal production of skin structural proteins and antimicrobial peptides. Ceramides are the waxy lipids that waterproof the skin barrier and can be rapidly converted to pro-inflammatory sphingosine-1 phosphate to signal inflammation.”
Although acute inflammation is necessary to fight off immediate threats, “sometimes the body does not turn off the inflammation or is signaling that it is being attacked when it is not,” Dr. Arbiser said.
“This underlies chronic inflammation, which is bad,” he said. “Similarly, mutations are happening in the skin all the time. For example, normally, the skin produces an inflammatory factor called IL-12 at a low level to harness the immune system to get rid of mutant cells. When the barrier is broken, IL-12 is diminished, allowing neoplastic cells to proliferate.”
As part of the session, Dr. Arbiser reviewed the development of compounds that could target signaling pathways to provide more effective relief for patients. That review included looking at key factors mediating skin barrier regulation and inflammation, including skin acidity, interleukins, nuclear factor kappa B, and sirtuin 3.
