- Bacterial pathways linked to skin aging have been discovered, according to a new study published in the journal PLOS One.
- The findings revealed that the creation of skin pigment, fatty acids, and ceramides are the key bacterial processes linked to aging.
- More study is needed to better understand the molecular pathways that promote skin aging and its interaction with the microbiome.
- Data from prospective trials might aid in the development of successful anti-aging treatments.
Bacteria, fungi, and viruses can be found on the skin and in the digestive tract. The skin is the body’s largest organ, and it serves as a protective barrier from the outside environment.
The skin microbiome, or commensal microbial communities on the skin, do not cause illness and are beneficial to the body. They may be fixed or exist temporarily on the skin.
The skin microbiota interacts with the immune system and may have an impact on its performance. The immune system also controls the composition of the skin microbiome.
The structure and function of the skin change as we age. Intrinsic causes, such as hormonal, metabolic, or immune system alterations, may cause this. Smoking, as well as exposure to sunshine and certain temperatures, can stimulate immunological responses that influence the structure and renewal of the skin.
Wrinkles appear, suppleness declines, wound healing slows, and the barrier function of the skin deteriorates as we age.
A reduction in the production of sebum, an oily material that protects the skin, as well as decreased water content in the skin and immunological dysfunction, can cause changes in the skin microbiome.
Changes in the microbiome as people become older
To analyze changes in the skin’s microorganisms caused by aging, advanced scientific approaches such as 16S ribosomal RNA gene and metagenomic sequencing techniques are now accessible.
The 16S ribosomal RNA sequencing technology, according to Dr. Elizabeth Grice, an associate professor of dermatology and microbiology at the University of Pennsylvania, allows us to “answer the questions [about] the makeup of a sample or the variety of a sample,” according to a 2019 lecture.
She went on to say that “Shotgun metagenomics provides a more nuanced view of the skin microbiome. Using these methods, one can take a sample containing the genomic DNA, […] break up that DNA in the sample, and then sequence those fragments. This allows one to identify microbes to the species and strain level, it allows one to reconstruct the genetic and functional metabolic pathways within a sample and, importantly, it gives you a multi-kingdom view of the skin microbiome.”
Previous research has shown that specific species of Staphylococcus, Cutibacterium, Corynebacterium, and Acinetobacter bacteria are consistently found in the skin microbiomes of all individuals.
The makeup of the skin microbiome is affected by age, body area, gender, and geographic location. Despite the fact that prior study has linked changes in the nature of the skin microbiome to aging, researchers still didn’t completely comprehend the reasons behind these changes.
A team from NIZO Food Research in the Netherlands set out to learn more about the link between the body’s cellular processes, known as co-metabolism, and genes, or bacterial functions, that play a role in skin aging in a new research. The research was largely supported by Estée Lauder, a skincare company.
To begin, the researchers looked through current scientific literature for common physiological pathways between people and skin bacteria that are associated to intrinsic skin aging. The researchers next performed 16S ribosomal RNA sequencing testing on cheek samples from female individuals with diverse age-related skin alterations to corroborate the changes in skin microbiome composition found in previous investigations.
In Belgium, the researchers obtained skin swab samples from 25 healthy female subjects of European heritage, one from each cheek. The participants were divided into two age groups: 20–28 years old and 59–68 years old.
Participants with specified skin disorders and external factors linked to skin aging were excluded from the research. The following were some of the exclusion criteria:
- acne
- eczema
- psoriasis
- use of skin medications, such as antibiotics, antifungals, or steroids, within 1 month of the study
- smoking, or a history of smoking in the past 2 years
- tanning or sunbathing
- drinking more than 3 servings of alcohol per day
Bacterial pathways that cause skin aging
The researchers obtained reference genomes from the National Center for Biotechnology Information’s gene sequence database. The data covered genes linked to skin aging that had been found and validated by testing.
The researchers then employed microbial pathways to develop graphical models, which they used to examine the genomes of reference skin organisms, 16S ribosomal RNA sequencing tests, and data from direct genome analysis of skin samples.
The researchers discovered that bacterial processes connected to skin aging were linked to the formation of ceramides, lipids that make up the natural skin barrier, fatty acids, and pigmentation. Bacterial enzymes involved in protein glycation were also linked to skin aging, according to the study.
When sugars link to proteins like collagen and elastin in the skin, this is known as protein glycation. Skin elasticity and sagging can be caused by a buildup of glycation of collagen and elastin end products.
Dr. Dina F. Bierman, a board-certified dermatologist at Providence Saint John’s Health Center who was not involved in the research, said:
“[The study] went one step beyond what we already knew. […] They separated the population based [on] how their skin had aged. […] Making that distinction is very important, in terms of understanding how the bacteria and their presence are influencing the skin and the metabolic processes that influence aging.”
The study’s modest size and lack of variety, on the other hand, might restrict the generalizability of its findings.
Overall, the findings may serve as a foundation for future research aimed at better understanding how molecular mechanisms and the microbiota interact in skin aging.
The study, according to Dr. Bierman, is a solid beginning point, but “a lot more research [is needed] before we can truly tell what the different bacteria are doing and how they interact with each other, too, and how they can affect how our skin ages.”
