Scalp Microbiome and Sebum Composition in Japanese Male Individuals with and without Androgenetic Alopecia

Abstract

The skin microbiome and sebum may be associated with inflammation-related diseases of the scalp. To assess the pathogenesis and progression of androgenetic alopecia (AGA), we analyzed the composition of sebum and the bacterial and fungal microbiomes of the scalps of 118 Japanese male individuals with and without AGA, then discussed their roles in the pathogenesis of AGA. Sebum triglyceride and palmitic acid contents were higher in the AGA group than in the non-AGA group. Malassezia restricta, a lipophilic fungus that consumes palmitic acid, was abundant on the scalps of patients with AGA. Cutibacterium, Corynebacterium, and Staphylococcus were the most common genera in both groups, and patients with AGA exhibited scalp dysbiosis (increased abundance of Cutibacterium and decreased abundance of Corynebacterium). Our findings suggest that both sebum and the bacterial and fungal microbiomes of the scalp may be involved in the development of AGA.

A Potential Predictive Role of the Scalp Microbiome Profiling in Patients with Alopecia Areata: Staphylococcus caprae, Corynebacterium, and Cutibacterium Species

“…Several scientific published evidence have reported the strict correlation between microbial disequilibrium and skin conditions [ 4 , 5 , 7 , 8 , 9 , 10 ]. Given this growing body of literature, it is becoming increasingly clear that the modulation of the microbiota may be a novel and important adjunct modality.…”

“…The severity of AA was evaluated based on the extent of scalp hair loss, progression of disease, and response of treatment, and was divided into mild AA ( n = 26) and severe AA ( n = 7) ( Table 1 ). The scalp samples were obtained by means of swab procedure according to previously reported methods [ 8 , 9 , 10 ] with minor modifications. Sterile cotton swabs were soaked for at least 30 s in solution (0.9% NaCl and 0.1% Tween 20).…”

“…Due to its unique features, the scalp is expected to harbor a specific microbiome, which is expected to play a peculiar role in scalp conditions related to hair growth [ 7 ]. Several researchers studied the scalp microbiome profile regarding AA and they suggested the notion that an imbalance between skin microbes that maintain skin homeostasis causes inflammation [ 8 , 9 , 10 , 11 , 12 ]. Several microbes such as Cutibacterium acnes , Staphylococcus , and Malassezia were suggested to be implicated in AA, but it still needs to be clarified using various cohorts of different populations.…”

Short sequence repeats of the intergenic spacer regions of ribosomal RNA genes in Malassezia globosa and Malassezia restricta colonizing the scalps of male individuals with and without androgenetic alopecia

“…Our recent analysis of the scalp fungal microbiome revealed that the relative abundance and scalp colonization level of the lipophilic fungus Malassezia were higher in patients with AGA than in individuals without AGA. Therefore, Malassezia may be involved in the development or exacerbation of AGA 4 …”

“…The colonization levels of all Malassezia species were obtained from our previous report 4 . M. globosa and M. restricta colonization levels were further examined in the present study.…”