, in a small pilot study published in Experimental Dermatology.
“Human skin and its microbial inhabitants are also subject to the effects of external and environmental stressors, such as ultraviolet radiation,” wrote Erin M. Burns, MS, PhD, of the department of dermatology at the University of Alabama at Birmingham, and her coauthors. “Environmental factors specific to the individual may modulate colonization of skin microbiota, and knowledge of how they do so can advance our understanding of the delicate balance between host and microorganisms,” they added.
In the study, the researchers conducted a prospective analysis of six males with Fitzpatrick types I or II skin exposed to various sources of UVR, including UVA1 and narrowband UVB. Participants received differing doses of irradiation, which was applied to the left upper or mid-back.
Both pre- and postexposure skin samples were obtained directly and 24 hours following UVR exposure. DNA from the cutaneous swabs was isolated and replicated via sequencing technology, which was used to analyze the microbial makeup of each sample.
After genomic analysis, Dr. Burns and her colleagues found extensive microbial differences among participants at each data collection point. Bacterial composition of the skin biome was altered 24 hours post UVR exposure both within and between study subjects, which included species- and phylum-level changes. While changes varied widely, trends that they identified included a “general increase” in the phylum Cyanobacteria and decreases in the family Lactobacillaceae and Pseudomonadaceae, they wrote.
Two key limitations of the study were the small sample size and inclusion of male participants only, which limits the generalizability of the results, the authors noted.
“These findings could add new insight into the treatment of UV-induced cutaneous inflammation and other skin diseases linked to microbiome shifts or UVR exposure,” they concluded. Future studies, they added, could address “the question of a protective nature of microbial inhabitants of the healthy skin microbiome,” which “may pave the way for the use of prophylactic probiotics for dermatologic health management.”
This study was supported by grant funding from the National Institutes of Health and University of Alabama at Birmingham. The authors – from the University of Alabama as well as Henry Ford Hospital, Detroit, and Florida State University, Tallahassee – reported no conflicts of interest.
SOURCE: Burns EM et al. Exp Dermatol. 2018 Dec 02. doi: 10.1111/exd.13854.