Table 1_Aging-dependent skin microbiome alterations across body sites in a United Kingdom cohort.docx

IntroductionThe aging process profoundly influences not only the health and visual appearance of the skin, but also the composition of the microbial communities residing on its surface.
MethodsTo investigate these microbial changes, we employed a comprehensive, multi-scale approach that probes community composition, species interactions, and predicted metabolic function of the skin microbiome of the face and forearm in young and old age individuals from the United Kingdom using 16S rRNA gene sequencing.
ResultsOur findings revealed significant and site-specific age-related shifts in the microbiome involving diversity, interpersonal heterogeneity, network connectivity, and metabolic potential, suggesting loss of microbiome robustness and a shift towards a hyperdiversified, fragile microbial community in old age. Furthermore, we applied Dirichlet Multinomial Mixtures to uncover novel age-driven microbiome profiles unique across each skin site, highlighting Cutibacterium acnes, Staphylococcus hominis, and microbial community diversity as key differentiating biomarkers of the skin microbiome across the lifespan.
DiscussionOverall, through examining the aging skin microbiome from a systems perspective, our study reinforces and enhances the findings from previous aging microbiome studies and underscores the importance of site-specific differences in skin microbiome dynamics with age. These insights suggest that microbial interventions could mitigate age-related changes, enhancing skin health and wellbeing throughout life.

引言
衰老过程不仅会深刻影响皮肤的健康与外观状态，同时也会改变皮肤表面定植的微生物群落组成。

方法
为探究这类微生物群落变化，本研究采用了一套多尺度综合分析方法，借助16S rRNA基因测序（16S rRNA gene sequencing）技术，对英国年轻与老年群体面部及前臂的皮肤微生物组（skin microbiome）的群落组成、物种互作以及预测代谢功能进行了检测分析。

结果
本研究结果显示，皮肤微生物组的群落多样性、个体间异质性、网络连通性以及代谢潜能均存在显著的位点特异性衰老相关变化，这提示老年时期微生物组的稳定性出现下降，群落结构向高度多样化但脆弱的状态转变。此外，本研究借助狄利克雷多项混合模型（Dirichlet Multinomial Mixtures）挖掘出了不同皮肤位点特有的衰老驱动型微生物组特征，并指出痤疮丙酸杆菌（Cutibacterium acnes）、人葡萄球菌（Staphylococcus hominis）以及微生物群落多样性可作为贯穿人类生命周期的皮肤微生物组关键差异化生物标志物（biomarker）。

讨论
总体而言，本研究从系统生物学视角对衰老皮肤微生物组展开分析，不仅验证并拓展了既往衰老微生物组研究的结论，同时强调了皮肤微生物组动态变化的位点特异性随衰老进程的重要性。上述研究结果提示，微生物干预手段或可缓解衰老相关的皮肤微生物组变化，从而在全生命周期中改善皮肤健康与整体状态。