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Understanding the changes in the skin microbiome and their relationship to host skin factors during aging remains largely unknown. To better understand this phenomenon, we collected samples for metagenomic and host skin factor analyses from the forearm, buttock, and facial skin from 158 Caucasian females aged 20‒24, 30‒34, 40‒44, 50‒54, 60‒64, and 70‒74 years. Metagenomics analysis was performed using 16S ribosomal RNA gene sequencing, whereas host sebocyte gland area, skin lipids, natural moisturizing factors, and antimicrobial peptides measurements were also performed. These analyses showed that skin bacterial diversity increased at all the skin sites with increasing age. Of the bacterial genera with an average relative abundance >1%, only Lactobacillus and Cutibacterium demonstrated a significant change (decrease) in abundance at all sampled skin sites with increasing age. Additional bacterial genera demonstrated significant age- and site-specific changes in abundance. Analysis of sebocyte area, natural moisturizing factors, lipids, and antimicrobial peptides showed an age-related decrease in sebocyte area and increases in natural moisturizing factors/antimicrobial peptides/skin lipids, all of which correlated with changes in specific bacterial genera. In conclusion, the human skin microbiome undergoes age-associated alterations that may reflect underlying age-related changes in cutaneous biology., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

The temporal and spatial distribution, and relative levels of the proteoglycan decorin and collagen type I were examined during the progression of atherosclerosis in the dorsal aortas of Japanese quail selected for cholesterol induced atherosclerosis. The quail were placed on either a control or 0.5% added cholesterol diet at approximately 16 weeks of age. Dorsal aortas were collected at 1- or 2-week intervals over a 15-week period after initiating cholesterol feeding. Biochemical analysis for decorin and collagen type I showed that both increased in the cholesterol-fed birds compared to control-fed birds beginning at 9 weeks and continued through the duration of the study. Through immunohistochemical staining for decorin and collagen type I, the spatial localization of decorin and collagen type I in control and less severe plaques in cholesterol-fed birds was most prominent in the arterial adventitia. However, in severe atherosclerotic plaques, decorin was localized in foam cell regions and collagen type I was found surrounding the foam cell regions where decorin accumulated. These results demonstrated a localization of decorin in the core of the atherosclerotic plaque foam cell region with collagen type I being located on the plaque surface.