The skin is an incredible organ that serves as the body’s first line of defense against external pathogens and environmental insults. Not only does it protect us from harm, but it also plays a crucial role in temperature regulation and moisture retention. However, there is a common misconception that lipids, which include fats, oils, and waxes, are detrimental to the skin due to their association with oiliness and acne. Contrary to this belief, lipids are actually essential components of the outermost layer of the skin and are vital for maintaining its protective barrier.
Lipids are organic compounds that are integral to the structure and function of the skin barrier. They contribute to the overall lipid composition of the skin and are involved in various processes, including moisture retention and protection against damage. When there are changes to the lipid composition of the skin, its ability to function as an effective barrier becomes compromised, leading to the development of skin diseases like eczema and psoriasis.
The human skin is home to thousands of different species of bacteria, collectively known as the skin microbiome. While some of these bacteria are well-known for their involvement in causing acne, such as Cutibacterium acnes (C. acnes), their broader effects on skin health are still not fully understood. Recent research conducted by the Gallo Lab at the University of California, San Diego sheds light on the role of C. acnes in maintaining the skin barrier.
In collaboration with SILAB, a company specializing in skincare product development, the researchers exposed keratinocytes, the cells that make up the epidermis, to various bacteria naturally present on the skin. Through their analysis, they discovered that only C. acnes triggered a significant increase in lipid production within these cells. This increase encompassed different types of lipids, including ceramides, cholesterol, and triglycerides, all of which are crucial for maintaining the skin barrier.
Further investigation revealed that C. acnes induces the increase in lipid production by producing a short-chain fatty acid called propionic acid. Propionic acid creates an acidic skin environment that offers several benefits, such as limiting the growth of pathogens, reducing staph infections, and contributing to anti-inflammatory effects in the gut. The researchers also identified the specific gene and receptor responsible for regulating lipid synthesis through C. acnes. Disrupting these components effectively blocked the C. acnes-induced lipid synthesis.
The research findings suggest that propionic acid derived from C. acnes has multiple advantageous effects on the skin barrier. By increasing the lipid content in skin cells, propionic acid helps reduce water loss through the skin, thereby improving its barrier function. Additionally, the lipids produced by skin cells after exposure to C. acnes or propionic acid have antimicrobial effects against C. acnes itself. This dual role of the lipids demonstrates their ability to not only control the presence of C. acnes on the skin but also maintain the overall balance of the skin microbiome, preventing the dominance of any single microbial species.
In the intricate relationship between the skin and its microbial inhabitants, the ubiquitous C. acnes is emerging as a significant player. Further research into the skin microbiome and its interactions may provide valuable insights that could lead to the development of innovative treatments for various skin conditions. By understanding the role of lipids and skin bacteria in maintaining the skin barrier, it may be possible to develop targeted therapies that restore and optimize the skin’s natural defense mechanisms, improving overall skin health.