MADRID, 30 Sep. (EUROPA PRESS) –
The microbiome, or the collection of microbes that live on and in the human body, is known to play a role in human health and the skin is no different. There is a lot of talk about the good microbes that populate the body but very little about the bad ones, which there are also, and their consequences for the body.
A new study by a team at George Washington University in the United States has observed that the composition of the skin microbiome varies depending on the dry, moist and oily regions of the skin. But they have shown something more important and that is that grandmothers are right when they recommend rubbing behind the ears and between the toes when showering to help keep the skin in those regions healthy.
Researchers at the GW Institute for Computational Biology wanted to take a closer look at the skin microbiome of healthy people. Marcos Pérez-Losada, associate professor of biostatistics and bioinformatics at the GW Milken Institute School of Public Health, and his team were interested in testing what they call ‘The Grandmother Hypothesis.’
What is ‘The Grandmother Hypothesis’? Director of the Institute for Computational Biology and professor of biostatistics and bioinformatics at GW, Keith Crandall, recalled that her grandmother always told the children in her family to rub behind their ears, between their toes, and in the belly button. Crandall postulated that these hot spots are typically washed less frequently compared to the skin on the arms or legs and therefore may harbor different types of bacteria.
Under this possibility, and with the aim of seeing if Crandall’s abula was right, Pérez-Losada and Crandall decided to put this theory to the test and, to do so, they designed an innovative genomics course and launched a team of students to help them. to discover it.
This team of students, specifically 129 graduate and undergraduate students, were taught to collect their own data, taking samples from certain wet and oily spots, behind the ears, between the toes and in the navel. They also collected samples from dry control areas such as the calves and forearms. And so they were for 4 years, from 2019 to 2023.
The students learned how to extract and sequence the DNA in their skin samples to compare the microbes living in hot spots with those in control regions.
Thus, the researchers found that forearms and calves, which are often cleaned more thoroughly at bath time, had a greater diversity and therefore a potentially healthier collection of microbes compared to samples taken in the critical points.
Dry skin regions (forearms and calves) were more uniform, richer, and functionally distinct than sebaceous (behind the ears) and moist (navel and between the toes) regions. Within skin regions, bacterial alpha and beta diversity also varied significantly during some of the years compared, suggesting that skin bacterial stability may be region- and subject-dependent.
Regarding the bacteria found, the study shows that dry skin regions (forearms and calves) were more uniform, richer and functionally different than sebaceous (behind the ears) and moist (navel and between the toes) regions. ). Within skin regions, bacterial alpha and beta diversity also varied significantly during some of the years compared, suggesting that skin bacterial stability may be region- and subject-dependent.
The bacteriome protects us against invading pathogens by training and communicating with our immune system, and is involved in wound healing and the breakdown of natural products. The skin bacteriome houses millions of bacteria, which rival the intestinal microbiome in composition and diversity. Typically, the bacterial community composition of the skin of healthy individuals is dominated by members of the phyla Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes.
The species of ‘Cutibacterium’ (previously known as Propionibacterium) seem to predominate in sebaceous areas, ‘Corynebacterium’, ‘B-Proteobacteria’ and ‘Staphylococcus’ in humid sites, while in dry sites a mixed population of these bacteria and ‘Flavobacteriales’. Similarly, these two studies have also shown that sebaceous sites were less uniform and rich than moist and dry sites.
Overall, they noted that fungal components may be particularly important in places such as between the toes and yeast components behind the ears.
When certain problematic microbes take over the microbiome, they can throw health off balance. If the microbiome is tilted in favor of harmful microbes, the result can be skin diseases such as eczema or acne. The students tested the grandmother hypothesis and their results suggested that cleaning habits can change the microbes that live on the skin and, consequently, its health.
This research, which includes a previous study by the same team, is one of the first to analyze the diversity of sites in the skin microbiome in healthy adult subjects and may provide a reference point for future research.
This study, which has been published in the journal ‘Frontiers in Microbiology’, on how the accumulation of microbes on the skin leads to health problems or, on the contrary, improves the skin, is currently in the early stages.
