Viruses, bacteria, and fungi live on the skin and in the gut. The body’s largest organ is the skin which protects from the outside environment. The skin microbiome (commensal microbial communities) does not benefit the body and doesn’t cause disease. On the skin, they may exist temporarily or fixed. This interacts with the body’s immune system and may affect its functioning. The immune system regulates the makeup of the skin microbiome.
The skin structure and function are changed when person ages and this may result from hormonal, metabolic, or immune system changes, smoking, exposure to sunlight, and specific temperatures. Increased wrinkles, reduced wound healing, decreased elasticity, and impaired barrier function are skin changes that occur during aging. Changes in the skin microbiome can also occur because of a decline in sebum production, decreased water content in the skin, and immune dysfunction. Sebum is an oily substance that protects the skin.
Metagenomic and 16S ribosomal RNA gene sequencing techniques are now available to assess changes in the skin’s microbes caused by aging. Previous studies have shown that skin microbiomes of all humans consistently contain certain species of Acinetobacter bacteria, Corynebacterium, Cutibacterium, Staphylococcus. The composition of the skin microbiome can be affected by geographic location, gender, body area, and age. Previous researches have identified changes in the makeup of the skin microbiome related to aging. But the mechanisms behind these changes are not fully understood.
New research on the skin –
A team from NIZO Food Research in the Netherlands conducted a new study. The researchers tried to understand the connection between co-metabolism (the body’s cellular processes) and bacterial functionalities or genes involved in skin aging. The study excluded participants with certain external factors and skin conditions related to skin aging. This includes drinking more than three servings of alcohol per day, tanning or sunbathing, smoking, use of skin medications within one month of the study, psoriasis, eczema, acne.
The process followed –
- 1st the researchers searched existing scientific literature. The purpose was to identify common biologic pathways between skin microbes and humans linked to skin aging.
- Then 16S ribosomal RNA sequencing testing was used. To confirm the skin microbiome composition changes seen in selected studies, the researchers used cheek samples of female participants with various age-related skin changes.
- From 25 healthy female participants, the skin swab was taken, one from each cheek. All were of European descent in Belgium. There were two age groups among the participants, one aged 59-68 and the other 20-28.
- From the gene sequences database of the National Center for Biotechnology Information, the team gathered reference genomes.
- Then microbial pathways were used to create graphical models.
- It was found that bacterial pathways linked to skin aging were related to the production of ceramides. These are lipids that compose the natural skin barrier, fatty acid, and pigmentation.
- The bacterial enzymes were also determined involved in protein glycation were associated with skin aging.
Limitations of the study –
- The study is small in size and lacks diversity, which may limit the generalizability of its findings.
- The result of the study may serve as a basis for future studies.