Skin repair may eliminate chronic diseases associated with inflammatory aging

The skin covers the whole body and is the largest organ of the human body. It mainly plays the role of protecting the body, perspiration, feeling cold and heat. The skin has two barrier functions: on the one hand, it prevents the loss of water, electrolytes and other substances in the body; on the other hand, it keeps the intrusion of harmful substances from the outside.

A recent study led by scientists at the University of California, San Francisco and the San Francisco Veterans Administration (VA) Health Care System showed that skin may be the main cause of systemic inflammation, which is linked to many chronic aging diseases.

In the study, published in the European Journal of Dermatology and Sexual Diseases, the researchers pointed out that proper care of the skin with a moisturizer may reduce inflammation levels and may prevent age-related diseases.

In the process of natural aging, the body will have a progressive increase in chronic pro-inflammatory response, known as "inflammatory aging". Inflammatory aging is a chronic, low-grade inflammatory condition that occurs with aging. This age-related inflammation is associated with many serious chronic diseases, including Alzheimer's disease, cardiovascular disease, and diabetes.

Scientists initially thought that inflammation originated in the immune system or the liver, but a group of dermatologists at the University of California, San Francisco had different theories. They believed that inflammation must come from a large enough organ, and then very mild inflammation can affect the entire body. The skin is a suitable candidate due to its size. Once we get older, our skin can also have various problems such as itching, dryness and acidity changes. It may be that the skin has a slight inflammation because it is such a large organ that it raises the level of circulating cytokines.

As the age increases, the skin's epidermal pH, hydration and permeability barriers continue to change, and our skin begins to deteriorate at around 50 years of age. A permeable barrier prevents water from entering the skin and keeps bacteria and other potential pathogens out of the skin.

Loss of moisture and destruction of the permeable barrier cause the skin to release inflammatory cytokines. Typically, these cytokines help to repair defects in the barrier, but in aged skin, the barrier cannot be easily restored, so the inflammatory signal continues to release and eventually reaches the bloodstream.

Previous studies have shown that skin inflammation caused by diseases such as psoriasis and dermatitis may increase the risk of heart disease. Until recently, the scientific community believed that the skin could cause systemic inflammation and disease. Aging skin is more common than psoriasis or dermatitis, so the overall risk of aging skin to the population may be much greater than a skin disease. Reducing inflammation by treating skin dysfunction that occurs during aging can have serious health effects.

The researchers selected 33 elderly people between the ages of 58 and 95 and applied the cream twice daily to their bodies for 30 days. This is an over-the-counter skin cream formulated by researchers based on previous research. Researchers have previously shown that this skin cream helps skin repair based on a beneficial ratio of three lipids that are essential for skin health: cholesterol, free fatty acids, and ceramides.

A month later, the researchers measured the blood levels of three cytokines: IL1B (interleukin-1β), IL6 (interleukin-6), and TNF-α (tumor necrosis factor α), all of which have been demonstrated to increase with age and involve in the pathogenesis of most age-related diseases.

The use of the cream reduced the amount of all three cytokines compared to the level of participants prior to the use of the cream and the level of similar age adults who did not use the cream. In fact, the use of cream to decreased participants' cytokine levels is almost equivalent to that of people in their 30s, suggesting that restoring the skin can reverse "inflammatory aging". This cream also improves skin moisture, lowers pH and repairs the skin's permeability barrier.

Scientists will continue to study whether reduced cytokine levels due to the use of creams can delay or prevent age-related inflammatory diseases.