Bacteria in the gut have been linked to baldness
A new study has found that certain bacteria in the gut are linked to alopecia areata, a pathological hair loss that leads to partial or complete baldness in humans.
The authors of the paper - specialists at Hangzhou Dermatology Hospital within Zhejiang Chinese Medical University (PRC) - focused on focal, or nested, alopecia (Alopecia areata). This common form of zonal hair loss is categorized as an autoimmune disease. It usually manifests as a few rounded bald spots on the head or in the beard area.
Among the possible factors of nested baldness are psychological stress and other diseases, but in most cases there are no clear causes. The disease can appear suddenly and occurs more often in genetically predisposed people. From the scientific literature, we know that approximately two percent of the population faces focal alopecia areata.
Scientists are aware of the impact of gut microflora on immune function and the risk of other autoimmune diseases such as psoriasis. However, the link between gut bacteria and baldness has been less studied. Chinese researchers have set out to fill the gaps in this area.
In a paper published in the International Journal of Dermatology, the authors analyzed the summary statistics of the MiBioGen and FinnGen consortiums' Genome-wide association studies (GWAS) containing data sets on gut microbiota and alopecia areata. The researchers used Mendelian randomization (MR) and a reverse MR approach using five statistical methods to assess the causal relationship between the two.
The analysis showed that some species of gut bacteria, such as Butyricimonas, Enterorhabdus, Eubacterium (xylanophilum group) and Phascolarctobacterium, can protect against baldness. At the same time, the presence of Ruminococcaceae UCG-003 microorganisms in the gut has been shown to be a risk factor for focal alopecia.
Past studies have shown that the short-chain fatty acids that certain gut bacteria, such as Butyricimonas, produce can influence how the human body responds to inflammation. This is consistent with the concept of the gut-skin axis, which suggests a bidirectional interaction between skin tissue and the gut microbiota.
The identified role of Ruminococcaceae UCG-003 bacteria as a risk factor for alopecia, despite their ability to produce short-chain fatty acids, suggests that very complex processes occur in the gut microbial community. The authors emphasized that more research is needed to fully understand, and urged caution in interpreting the results of the paper.
Scientists hope that, having understood the mechanisms of influence of gut bacteria on alopecia, in the future they will be able to develop strategies for the treatment and prevention of pathological baldness.