Shift in skin microbiota of Western European women across aging

Facial Skin Microbiome Composition and Functional Shift with Aging

The change in the skin microbiome as individuals age is only partially known. To provide a better understanding of the impact of aging, whole-genome sequencing analysis was performed on facial skin swabs of 100 healthy female Caucasian volunteers grouped by age and wrinkle grade. Volunteers' metadata were collected through questionnaires and non-invasive biophysical measurements. A simple model and a biological statistical model were used to show the difference in skin microbiota composition between the two age groups. Taxonomic and non-metric multidimensional scaling analysis showed that the skin microbiome was more diverse in the older group (≥55 yo). There was also a significant decrease in Actinobacteria, namely in Cutibacterium acnes, and an increase in Corynebacterium kroppenstedtii. Some Streptococcus and Staphylococcus species belonging to the Firmicutes phylum and species belonging to the Proteobacteria phylum increased. In the 18-35 yo younger group, the microbiome was characterized by a significantly higher proportion of Cutibacterium acnes and Lactobacillus, most strikingly, Lactobacillus crispatus. The functional analysis using GO terms revealed that the young group has a higher significant expression of genes involved in biological and metabolic processes and in innate skin microbiome protection. The better comprehension of age-related impacts observed will later support the investigation of skin microbiome implications in antiaging protection.

Menopause and facial skin microbiomes: a pilot study revealing novel insights into their relationship

Introduction: The human skin microbial composition is affected by age. Previous studies reported skin microbiome diversity shifts between elderly and significantly younger subjects. Some studies implied that menopausal status, which is inherently linked to age, could be associated with changes in skin microbial compositions. Nevertheless, the influence of menopausal status on skin microbiome profiles while minimizing the impact of aging-associated changes in skin parameters still needs further clarification. Methods: We performed an observational study on healthy Caucasian female volunteers, which were grouped according to their pre- or postmenopausal status. Bacterial community structures on facial skin were analyzed using 16S rRNA gene sequencing. Cutometer® measurements were performed to evaluate aging-associated changes in facial skin biophysical properties. Results: The relative abundance of the lipophilic Cutibacterium genus was decreased, and bacterial diversity was increased in skin samples of postmenopausal volunteers. The mean age difference between examined groups in this study was 12.4 years only. Accordingly, Cutometer® measurements revealed no differences in aging-associated skin biophysical parameters between pre- and postmenopausal groups. Consequently, no correlation was detected between Shannon diversity and measured age-dependent biomechanical properties of facial skin. Discussion: These findings are in line with previous studies, which investigated the wide-ranging impact of chronological aging on skin microbial communities. However, this work reports for the first time a direct association between menopausal status and facial microbiomes on skin of similarly aged study participants, and hence uncouples aging-associated skin biophysical parameters, such as viscoelastic properties, from the equation. These findings open avenues for the development of microbiome-targeting strategies for treatment of menopause-associated skin disorders.

Predicting Chronological Age via the Skin Volatile Profile

Skin volatile emissions offer a noninvasive insight into metabolic activity within the body as well as the skin microbiome and specific volatile compounds have been shown to correlate with age, albeit only in a few small studies. Building on this, here skin volatiles were collected and analyzed in a healthy participant study (n = 60) using a robust headspace-solid phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS) workflow. Following processing, 18 identified compounds were deemed suitable for this study. These were classified according to gender influences and their correlations with age were investigated. Finally, 6 volatiles (of both endogenous and exogenous origin) were identified as significantly changing in abundance with participant age (p < 0.1). The potential origins of these dysregulations are discussed. Multiple linear regression (MLR) analysis was employed to model age based on these significant volatiles as independent variables, along with gender. Our analysis shows that skin volatiles show a strong predictive ability for age (explained variance of 68%), stronger than other biochemical measures collected in this study (skin surface pH, water content) which are understood to vary with chronological age. Overall, this work provides new insights into the impact of aging on the skin volatile profiles which comprises both endogenously and exogenously derived volatile compounds. It goes toward demonstrating the biological significance of skin volatiles and will help pave the way for more rigorous consideration of the healthy "baseline" skin volatile profile in volatilomics-based health diagnostics development going forward.

Skin dysbiosis and loss of microbiome site specificity in critically ill patients

An increasing amount of evidence has linked critical illness with dysbiotic microbiome signatures in different body sites. The disturbance of the indigenous microbiota structures has been further associated with disease severity and outcome and has been suggested to pose an additional risk for complications in intensive care units (ICUs), including hospital-acquired infections. A better understanding of the microbial dysbiosis in critical illness might thus help to develop strategies for the prevention of such complications. While most of the studies addressing microbiome changes in ICU patients have focused on the gut, the lung, or the oral cavity, little is known about the microbial communities on the skin of ICU patients. Since the skin is the outermost organ and the first immune barrier against pathogens, its microbiome might play an important role in the risk management for critically ill patients. This observational study characterizes the skin microbiome in ICU patients covering five different body sites at the time of admission. Our results show a profound dysbiosis on the skin of critically ill patients, which is characterized by a loss of site specificity and an overrepresentation of gut bacteria on all skin sites when compared to a healthy group. This study opens a new avenue for further investigations on the effect of skin dysbiosis in the ICU setting and points out the need of strategies for the management of dysbiosis in critically ill patients.IMPORTANCEUnbalanced gut microbiota in critically ill patients has been associated with poor outcome and complications during the intensive care unit (ICU) stay. Whether the disturbance of the microbial communities in these patients is extensive for other body sites, such as the skin, is largely unknown. The skin not only is the largest organ of the body but also serves as the first immune barrier against potential pathogens. This study characterized the skin microbiota on five different body sites in ICU patients at the time of admission. The observed disturbance of the bacterial communities might help to develop new strategies in the risk management of critically ill patients.

Longitudinal analysis of the skin microbiome in association with hand eczema, hand hygiene practices and moisturizer use

BACKGROUND

The skin microbiota maintains a physical and immunological barrier to the environment. Little is known about how the microbiome changes over time or the effect of hand hygiene practices and moisturizer use.

OBJECTIVES

To assess sex-specific changes in skin bacteria over time, and how the microbiome is related to self-reported hand eczema, hand hygiene practices and use of moisturizers.

METHODS

Swab samples from the dorsal hand were collected at baseline and 6.5 years later during the COVID-19 pandemic, in 168 participants from the RHINESSA study in Bergen, Norway. The skin samples were analysed by 16S rRNA amplicon sequencing.

RESULTS

The alpha diversity of the hand microbiome increased from baseline to follow-up, and beta diversity differed by sex at both time points. The relative abundance increased for several bacteria from baseline to follow-up, with sex-specific differences. Current hand eczema and aggravating hand eczema during the COVID-19 pandemic were associated with an increase in Staphylococcus. High hand washing frequency at home was associated with lower alpha diversity and with higher abundance of Staphylococcus, Corynebacterium, Finegoldia, and Pseudomonas and lower abundance of Propionibacterium and Pelomonas. The alpha diversity increased with increasing time passing between hand washing and sampling, whereas more frequent moisturizer use was associated with significantly lower alpha diversity, and a change in abundance for some bacteria, such as more Pseudomonas.

CONCLUSIONS

This longitudinal study revealed an overall increase in skin microbial diversity over a 6-year period, which was unexpected since follow-up was performed during the COVID-19 pandemic when vigorous hand hygienic practices were introduced. Sex-specific differences were identified at both time points. Individuals with hand eczema seem to develop a more dysbiotic skin bacterial community over time. Hand washing and use of moisturizers, with typically gender-specific habitual patterns, may lead to change in bacterial composition.

Interaction between the microbiota and the skin barrier in aging skin: a comprehensive review

The interplay between the microbes and the skin barrier holds pivotal significance in skin health and aging. The skin and gut, both of which are critical immune and neuroendocrine system, harbor microbes that are kept in balance. Microbial shifts are seen with aging and may accelerate age-related skin changes. This comprehensive review investigates the intricate connection between microbe dynamics, skin barrier, and the aging process. The gut microbe plays essential roles in the human body, safeguarding the host, modulating metabolism, and shaping immunity. Aging can perturb the gut microbiome which in turn accentuates inflammaging by further promoting senescent cell accumulation and compromising the host's immune response. Skin microbiota diligently upholds the epidermal barrier, adeptly fending off pathogens. The aging skin encompasses alterations in the stratum corneum structure and lipid content, which negatively impact the skin's barrier function with decreased moisture retention and increased vulnerability to infection. Efficacious restoration of the skin barrier and dysbiosis with strategic integration of acidic cleansers, emollients with optimal lipid composition, antioxidants, and judicious photoprotection may be a proactive approach to aging. Furthermore, modulation of the gut-skin axis through probiotics, prebiotics, and postbiotics emerges as a promising avenue to enhance skin health as studies have substantiated their efficacy in enhancing hydration, reducing wrinkles, and fortifying barrier integrity. In summary, the intricate interplay between microbes and skin barrier function is intrinsically woven into the tapestry of aging. Sound understanding of these interactions, coupled with strategic interventions aimed at recalibrating the microbiota and barrier equilibrium, holds the potential to ameliorate skin aging. Further in-depth studies are necessary to better understand skin-aging and develop targeted strategies for successful aging.

A multi-study analysis enables identification of potential microbial features associated with skin aging signs

Introduction: During adulthood, the skin microbiota can be relatively stable if environmental conditions are also stable, yet physiological changes of the skin with age may affect the skin microbiome and its function. The microbiome is an important factor to consider in aging since it constitutes most of the genes that are expressed on the human body. However, severity of specific aging signs (one of the parameters used to measure "apparent" age) and skin surface quality (e.g., texture, hydration, pH, sebum, etc.) may not be indicative of chronological age. For example, older individuals can have young looking skin (young apparent age) and young individuals can be of older apparent age. Methods: Here we aim to identify microbial taxa of interest associated to skin quality/aging signs using a multi-study analysis of 13 microbiome datasets consisting of 16S rRNA amplicon sequence data and paired skin clinical data from the face. Results: We show that there is a negative relationship between microbiome diversity and transepidermal water loss, and a positive association between microbiome diversity and age. Aligned with a tight link between age and wrinkles, we report a global positive association between microbiome diversity and Crow's feet wrinkles, but with this relationship varying significantly by sub-study. Finally, we identify taxa potentially associated with wrinkles, TEWL and corneometer measures. Discussion: These findings represent a key step towards understanding the implication of the skin microbiota in skin aging signs.

Skin microbiome attributes associate with biophysical skin ageing

Two major arms of skin ageing are changes in the skin's biophysical conditions and alterations in the skin microbiome. This work partitioned both arms to study their interaction in detail. Leveraging the resolution provided by shotgun metagenomics, we explored how skin microbial species, strains and gene content interact with the biophysical traits of the skin during ageing. With a dataset well-controlled for confounding factors, we found that skin biophysical traits, especially the collagen diffusion coefficient, are associated with the composition and the functional potential of the skin microbiome, including the abundance of bacterial strains found in nosocomial infections and the abundance of antibiotic resistance genes. Our findings reveal important associations between skin biophysical features and ageing-related changes in the skin microbiome and generate testable hypotheses for the mechanisms of such associations.

Sacha inchi albumin delays skin-aging by alleviating inflammation, oxidative stress and regulating gut microbiota in d-galactose induced-aging mice

BACKGROUND

Sacha inchi albumin exhibits considerable functional activity with notable anti-inflammatory and antioxidation properties, which could delay skin aging. However, its underlying mechanisms for delaying skin aging have not been elucidated. The aim of the present study was to investigate the anti-skin-aging effect of sacha inchi albumin (SIA) in d-galactose induced-aging mice.

RESULTS

Sacha inchi albumin improved moisture content, collagen level, and the state of aged skin in rats. Sacha inchi albumin intervention markedly increased the skin antioxidant enzymatic activities including those of glutathione peroxidase, and catalase, but decreased the malondialdehyde content. It also regulated inflammation by reducing the level of tumor necrosis factor-α (TNF-α) and increasing the level of interleukin-6 (IL-6). Administration of SIA also increased the expression level of collagen I and III, increased the expression of tissue inhibitor of metalloprotease-1, and decreased the expression of metalloproteinases. Sacha inchi albumin can also activate the transforming growth factor-β (TGF-β)/Smad pathway. Meanwhile, 16S rRNA sequencing analysis revealed that SIA treatment altered the composition of microbiota, and increased the relative abundance of Lactobacillus, but decreased the relative abundance of Alloprevotella and Helicobacter, etc. Helicobacter was positively associated with malondialdehyde (MDA) content and was negatively related to IL-6.

CONCLUSION

Sacha inchi albumin exhibits excellent anti-skin-aging effect, which provide a new insight for the development of functional sacha inchi albumin. © 2023 Society of Chemical Industry.

Dynamic Distribution of Skin Microorganisms in Donkeys at Different Ages and Various Sites of the Body

Considerable evidence suggests that the skin microbiota is not only important and complex in humans and other mammals but also critical for maintaining health and skin homeostasis. To date, studies on the skin microorganisms of donkeys are surprisingly rare. To investigate the dynamic changes in commensal microbial communities on the skins of healthy donkeys throughout the growing period, skin and soil samples were collected from 30 healthy Dezhou donkeys (ranging from 1, 6, 12, 24 to 48 months of age) and their corresponding breeding sheds on the farm. All samples were analysed for high-throughput sequencing of the 16S rRNA and ITS to characterize the skin microbiota of healthy donkeys and compare the differences in skin microbiota among donkeys of different ages. There were notable differences in the proportions of various genera (including bacteria and fungi) between dorsal and abdominal skin with increasing age. The comparison of the skin microbial communities among these groups revealed that Staphylococcus was mainly enriched in the early growing stage (1 and 6 months), while the relative abundance of Streptococcus was higher in both the 1- and 48-month-old age groups. Moreover, some bacteria and commensal fungi, such as Staphylococcus and Trichosporon, were found to be positively correlated between the skin and the environment. This is the first study to investigate the dynamic changes in skin microbiota diversity and composition in donkeys of different ages and at different sites of the body. Furthermore, this study provides insights into the dynamic alterations in skin microbes during a donkey's growth and characterizes the profiles of bacterial and fungal communities across a donkey's body regions (dorsal and abdomen).

The dynamic balance of the skin microbiome across the lifespan

For decades research has centered on identifying the ideal balanced skin microbiome that prevents disease and on developing therapeutics to foster this balance. However, this single idealized balance may not exist. The skin microbiome changes across the lifespan. This is reflected in the dynamic shifts of the skin microbiome's diverse, inter-connected community of microorganisms with age. While there are core skin microbial taxa, the precise community composition for any individual person is determined by local skin physiology, genetics, microbe-host interactions, and microbe-microbe interactions. As a key interface with the environment, the skin surface and its appendages are also constantly exchanging microbes with close personal contacts and the environment. Hormone fluctuations and immune system maturation also drive age-dependent changes in skin physiology that support different microbial community structures over time. Here, we review recent insights into the factors that shape the skin microbiome throughout life. Collectively, the works summarized within this review highlight how, depending on where we are in lifespan, our skin supports robust microbial communities, while still maintaining microbial features unique to us. This review will also highlight how disruptions to this dynamic microbial balance can influence risk for dermatological diseases as well as impact lifelong health.

Efficacy and Safety of Epidermidibacterium Keratini EPI-7 Derived Postbiotics in Skin Aging: A Prospective Clinical Study

The present study investigated the effect of topical application of Epidermidibacterium Keratini (EPI-7) ferment filtrate, which is a postbiotic product of a novel actinobacteria, on skin aging, by performing a prospective randomized split-face clinical study on Asian woman participants. The investigators measured skin biophysical parameters, including skin barrier function, elasticity, and dermal density, and revealed that the application of the EPI-7 ferment filtrate-including test product resulted in significantly higher improvements in barrier function, skin elasticity, and dermal density compared to the placebo group. This study also investigated the influence of EPI-7 ferment filtrate on skin microbiome diversity to access its potential beneficial effects and safety. EPI-7 ferment filtrate increased the abundance of commensal microbes belonging to Cutibacterium, Staphylococcus, Corynebacterium, Streptococcus, Lawsonella, Clostridium, Rothia, Lactobacillus, and Prevotella. The abundance of Cutibacterium was significantly increased along with significant changes in Clostridium and Prevotella abundance. Therefore, EPI-7 postbiotics, which contain the metabolite called orotic acid, ameliorate the skin microbiota linked with the aging phenotype of the skin. This study provides preliminary evidence that postbiotic therapy may affect the signs of skin aging and microbial diversity. To confirm the positive effect of EPI-7 postbiotics and microbial interaction, additional clinical investigations and functional analyses are required.

The Skin Microbiome: Current Landscape and Future Opportunities

Our skin is the largest organ of the body, serving as an important barrier against the harsh extrinsic environment. Alongside preventing desiccation, chemical damage and hypothermia, this barrier protects the body from invading pathogens through a sophisticated innate immune response and co-adapted consortium of commensal microorganisms, collectively termed the microbiota. These microorganisms inhabit distinct biogeographical regions dictated by skin physiology. Thus, it follows that perturbations to normal skin homeostasis, as occurs with ageing, diabetes and skin disease, can cause microbial dysbiosis and increase infection risk. In this review, we discuss emerging concepts in skin microbiome research, highlighting pertinent links between skin ageing, the microbiome and cutaneous repair. Moreover, we address gaps in current knowledge and highlight key areas requiring further exploration. Future advances in this field could revolutionise the way we treat microbial dysbiosis associated with skin ageing and other pathologies.

Role of Senescent Cells in Cutaneous Wound Healing

Cellular senescence has gained increasing attention in the field of aging research. Senescent cells have been implicated in biological aging processes, tumorigenesis, development, and wound repair amongst other processes and pathologies. Recent findings reveal that senescent cells can both promote and inhibit cutaneous wound healing processes. Relating senescent cells in acute and chronic wounds will help to clarify their role in wound healing processes and inform our understanding of senescent cell heterogeneity. To clarify this apparent contradiction and guide future research and therapeutic development, we will review the rapidly growing field of cellular senescence and its role in wound healing biology.

How Microbiomes Affect Skin Aging: The Updated Evidence and Current Perspectives

The skin has a multifactorial aging process, caused by both intrinsic and extrinsic factors. A major theory of aging involves cellular senescence or apoptosis resulting from oxidative damage as the skin’s antioxidant system tends to weaken with age. The human microbiota is a complex ecosystem that is made up of microorganisms (bacteria, fungi, and viruses). Both gut and skin microbiota have essential roles in the protection against invading pathogens, mediating inflammatory conditions, and the modulation of the immune system which is involved in both innate and adaptive immune responses. However, the human microbiome could be changed during the life stage and affected by various perturbations. An alteration of the intestinal bacteria results in “microbial dysbiosis” which is associated with the influence of various diseases, including aging. The skin interactome is a novel integration of the “genome-microbiome-exposome” that plays a significant role in skin aging and skin health. Mitigating the negative impacts of factors influencing the skin interactome should be the future strategy to protect, prevent, and delay skin aging along with preserving healthy skin conditions. This review summarizes the current evidence on how human microbiomes affect skin aging and demonstrates the possible interventions, relating to human microbiomes, to modulate skin health and aging. Probiotics-based products are currently available mainly for the add-on treatment of many dermatologic conditions. However, at this point, there are limited clinical studies on skin anti-aging purposes and more are required as this evolving concept is on the rise and might provide an insight into future therapeutic options.

Regular Late Bedtime Significantly Affects the Skin Physiological Characteristics and Skin Bacterial Microbiome

Background

Late bedtime is a common form of unhealthy sleep pattern in adulthood, which influences circadian rhythm, and negatively affects health. However, little is known about the effect of regular late bedtime on skin characteristics, particularly on skin microbiome.

Objective

To investigate the changes and effects of the regular late bedtime on skin physiological parameters and facial bacterial microbiome of 219 cases of Chinese women aged 18-38 years living in Shanghai.

Methods

Based on the Self-Evaluation Questionnaire, bedtime was categorized as 11:00 PM; thus, the volunteers were divided into early bedtime group (S0) and late bedtime group (S1). The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing.

Results

The skin physiological parameters of the late bedtime group exhibited significant decrease in skin hydration content, skin firmness (F4) and elasticity (R2), while TEWL, sebum and wrinkle significantly increased. The result indicated that late bedtime significantly impaired the integrity of skin barrier, damaged skin structure, and disrupted water-oil balance. Furthermore, the analysis of α-diversity, Sobs, Ace and Chao index were found to significantly decrease (P < 0.05) in the late bedtime group, suggesting that late bedtime reduced both the abundance and the diversity of facial bacterial microbiota. Moreover, the abundance of Pseudomonas increased significantly, while Streptococcus, Stenotrophomonas, Acinetobacter, Haemophilus, Actinomyces and Neisseria decreased significantly. In addition, Spearman correlation analysis revealed strong correlations between the microbiota and the physiological parameters. Notably, the abundance of Pseudomonas significantly positively correlated with skin firmness and elasticity, but significantly negatively correlated with skin hemoglobin content, melanin content and skin hydration.

Conclusion

Bedtime is an important factor in maintaining skin health. Regular late bedtime not only damages the skin barrier and skin structure but also reduces the diversity and composition of facial bacterial microbiome.

A Multi-Functional Anti-Aging Moisturizer Maintains a Diverse and Balanced Facial Skin Microbiome

AIMS

To assess the effect of a 28-day skincare regimen in healthy female subjects on the facial skin microbiome composition and to determine if the skincare regimen including a gentle cleansing lotion, a multi-functional anti-aging moisturizer formulated with prebiotics and postbiotics at skin neutral pH, and bland sunscreen pushed the microbiome to a healthier state and improved skin aging measured by self-assessment and clinical photography.

METHODS AND RESULTS

The study protocol was in accordance with the EU Scientific Committee on Consumer Safety (SCCS) guidance and met all international standards. Twenty-five female subjects between 35 to 65 years old with Fitzpatrick skin type I - VI, moderate crow's feet wrinkles and global face photodamage were enrolled. After 28 days the skincare regimen improved microbial facial diversity and shifted the microbiota composition when compared to baseline.

CONCLUSIONS

After 28-days, the skincare regimen treatment shifted the distribution of the facial skin microbiome, positively influencing the skin microbiome diversity and balance, to promote long term skin health and protect from further skin aging.

SIGNIFICANCE AND IMPACT OF STUDY

These results suggest that incorporating prebiotics and postbiotics into a skincare regimen may have a positive impact on the facial skin microbiome in healthy women.

Bacterial taxa predictive of hyperpigmented skins

Background and Aims

Dark spots, brown spots, or hyperpigmented spots (HPS) are oval or irregular brown areas of skin. Their emergence is associated with dysregulation of the immune system, and may also be caused by a deficiency in stromal cell‐derived factor‐1, leading to perturbed melanogenesis and accumulation of melanosomes within neighboring keratinocytes. The skin microbiota (living microorganisms present on the surface of the skin) is known to play essential roles in maintaining skin homeostasis and in regulating the immune system. Here, we investigated whether the microbiota could play a role in the emergence of HPS.

Methods

The clinical study involved 38 European women, selected from among 74 volunteers. Participants were divided into two groups depending on the spot areas measured on their faces. The study was designed to avoid conflicting factors: both groups presented similar skin pH, hydration, transepidermal water loss, and sebum levels. The two cohorts were also age‐matched, with a mean of 29‐years‐old for both.

Results

Alpha‐diversity of the microbiota was similar for the two groups. On skins with more HPS, seven bacterial genera were identified in significantly higher proportions and included opportunistic pathogens and inflammatory bacteria. Six bacterial genera, including bacteria showing antioxidant and anti‐UV properties, were identified in significantly higher proportions on less spotted skins. Cross‐domain association networks revealed distinct co‐occurrences of genera between the two groups, suggesting nonidentical community structures and exchanges, depending on the HPS status.

Conclusion

Our results reveal specific microbiota composition and networks on skins based on HPS status. Changes could alter communication with the immune system, leading to the emergence of dark spots. As an essential part of the overall skin ecosystem, and through its interaction with the skin matrix, the skin microbiota and its maintenance could be considered a new target for skincare applications.

Aged related human skin microbiome and mycobiome in Korean women

We examined differences in the skin microbiome of two separate age groups to find key microbial and skin physiological indicators associated with aging. We recruited healthy Korean women 19–28 years old (Y-group) and 60–63 years old (O-group) and evaluated their cheek and forehead skin microbiome, including bacteria and fungi. The microbiome was significantly different by age group, with bacterial and fungal communities displaying higher alpha-diversity in the O-group than in the Y-group. We identified amplicon sequence variants affiliated with Cutibacterium and Lactobacillus and fungi Malassezia restricta as microbial biomarkers showing significant differences between the Y and O-group. There are more microbial communities and metabolic processes related to skin health in the Y-group than in the O-group, and there are more microbial interactions to increase the stability of the network structure of the skin. Skin physical metadata, including transepidermal water loss and sebum content, differed by two age groups. The crucial skin microbes, skin physical parameters, and microbial network found through this research will be useful key indicators in associating skin aging and skin microbiome research.

Advances in Microbiome-Derived Solutions and Methodologies Are Founding a New Era in Skin Health and Care

The microbiome, as a community of microorganisms and their structural elements, genomes, metabolites/signal molecules, has been shown to play an important role in human health, with significant beneficial applications for gut health. Skin microbiome has emerged as a new field with high potential to develop disruptive solutions to manage skin health and disease. Despite an incomplete toolbox for skin microbiome analyses, much progress has been made towards functional dissection of microbiomes and host-microbiome interactions. A standardized and robust investigation of the skin microbiome is necessary to provide accurate microbial information and set the base for a successful translation of innovations in the dermo-cosmetic field. This review provides an overview of how the landscape of skin microbiome research has evolved from method development (multi-omics/data-based analytical approaches) to the discovery and development of novel microbiome-derived ingredients. Moreover, it provides a summary of the latest findings on interactions between the microbiomes (gut and skin) and skin health/disease. Solutions derived from these two paths are used to develop novel microbiome-based ingredients or solutions acting on skin homeostasis are proposed. The most promising skin and gut-derived microbiome interventional strategies are presented, along with regulatory, safety, industrial, and technical challenges related to a successful translation of these microbiome-based concepts/technologies in the dermo-cosmetic industry.

Aging Associated Changes in the Adult Human Skin Microbiome and the Host Factors That Affect Skin Microbiome Composition

Understanding 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 forearm, buttock, and facial skin from 158 Caucasian females at 20-24, 30-34, 40-44, 50-54, 60-64, and 70-74 years of age. Metagenomics analysis was performed using 16S rRNA gene sequencing, while host sebocyte gland area, skin lipids, natural moisturizing factors (NMFs) and anti-microbial peptides (AMPs) measurements were also performed. These analyses demonstrated that skin bacterial diversity increased at all the skin sites with increasing age. Of the bacterial genera with average relative abundance of >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, NMFs, lipids and AMPs demonstrated an age-related decrease in sebocyte area and increases in NMFs/AMPs/skin lipids, all 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.

Structural and Functional Changes and Possible Molecular Mechanisms in Aged Skin

Skin aging is a complex process influenced by intrinsic and extrinsic factors. Together, these factors affect the structure and function of the epidermis and dermis. Histologically, aging skin typically shows epidermal atrophy due to decreased cell numbers. The dermis of aged skin shows decreased numbers of mast cells and fibroblasts. Fibroblast senescence contributes to skin aging by secreting a senescence-associated secretory phenotype, which decreases proliferation by impairing the release of essential growth factors and enhancing degradation of the extracellular matrix through activation of matrix metalloproteinases (MMPs). Several molecular mechanisms affect skin aging including telomere shortening, oxidative stress and MMP, cytokines, autophagic control, microRNAs, and the microbiome. Accumulating evidence on the molecular mechanisms of skin aging has provided clinicians with a wide range of therapeutic targets for treating aging skin.

Charting host-microbe co-metabolism in skin aging and application to metagenomics data

During aging of human skin, a number of intrinsic and extrinsic factors cause the alteration of the skin’s structure, function and cutaneous physiology. Many studies have investigated the influence of the skin microbiome on these alterations, but the molecular mechanisms that dictate the interplay between these factors and the skin microbiome are still not fully understood. To obtain more insight into the connection between the skin microbiome and the human physiological processes involved in skin aging, we performed a systematic study on interconnected pathways of human and bacterial metabolic processes that are known to play a role in skin aging. The bacterial genes in these pathways were subsequently used to create Hidden Markov Models (HMMs), which were applied to screen for presence of defined functionalities in both genomic and metagenomic datasets of skin-associated bacteria. These models were further applied on 16S rRNA gene sequencing data from skin microbiota samples derived from female volunteers of two different age groups (25–28 years (‘young’) and 59–68 years (‘old’)). The results show that the main bacterial pathways associated with aging skin are those involved in the production of pigmentation intermediates, fatty acids and ceramides. This study furthermore provides evidence for a relation between skin aging and bacterial enzymes involved in protein glycation. Taken together, the results and insights described in this paper provide new leads for intervening with bacterial processes that are associated with aging of human skin.

A Journey on the Skin Microbiome: Pitfalls and Opportunities

The human skin microbiota is essential for maintaining homeostasis and ensuring barrier functions. Over the years, the characterization of its composition and taxonomic diversity has reached outstanding goals, with more than 10 million bacterial genes collected and cataloged. Nevertheless, the study of the skin microbiota presents specific challenges that need to be addressed in study design. Benchmarking procedures and reproducible and robust analysis workflows for increasing comparability among studies are required. For various reasons and because of specific technical problems, these issues have been investigated in gut microbiota studies, but they have been largely overlooked for skin microbiota. After a short description of the skin microbiota, the review tackles methodological aspects and their pitfalls, covering NGS approaches and high throughput culture-based techniques. Recent insights into the "core" and "transient" types of skin microbiota and how the manipulation of these communities can prevent or combat skin diseases are also covered. Finally, this review includes an overview of the main dermatological diseases, the changes in the microbiota composition associated with them, and the recommended skin sampling procedures. The last section focuses on topical and oral probiotics to improve and maintain skin health, considering their possible applications for skin diseases.

Nationality and body location alter human skin microbiome

Skin microbiomes function directly in human health and are affected by various external and internal factors. However, few studies have showed the variation of human skin microbiota at multiple body sites in individuals of different national origin living in the same environment. Here, using 16S rRNA sequencing, we investigated the diversity and function of skin microbiomes in different body locations of Chinese and Pakistani individuals from a single college in China. Body location and nationality significantly affected community structures, while season and gender only impacted community member. Due to different lifestyles and likely genetic characteristics of the hosts, Proteobacteria was more abundant in Pakistanis than in Chinese individuals. There were significant differences in the Shannon diversity of skin microorganisms among different skin sites of Chinese individuals, but not in Pakistanis. PICRUSt prediction indicated that gene functions involved in carbohydrate metabolism, lipid metabolism, and xenobiotics biodegradation and metabolism were higher in bacteria collected from Pakistanis than those from Chinese individuals, but the amino acid metabolism of skin microorganisms in Chinese people was higher. The relative abundances of potential pathogenic bacteria also differed in different body locations, providing a foundation for studying skin-associated bacterial diseases. Through a meta-analysis of 233 human skin samples from eight elevational sites in western China, we found that skin microbial diversity first decreased and then increased with increasing altitude. Network analysis showed positive correlation between altitude and Lactobacillus, Chryseobacterium, or Acinetobacter. Our results uncover the variation of human skin microbiota allowing future explorations of potential significance for human health. KEY POINTS: • Body location and nationality affect skin microbiota diversity and function. • Proteobacteria was more abundant in Pakistanis than in Chinese. • Skin microbial diversity first decreased and then increased with elevated altitude.

Challenges in exploring and manipulating the human skin microbiome

The skin is the exterior interface of the human body with the environment. Despite its harsh physical landscape, the skin is colonized by diverse commensal microbes. In this review, we discuss recent insights into skin microbial populations, including their composition and role in health and disease and their modulation by intrinsic and extrinsic factors, with a focus on the pathobiological basis of skin aging. We also describe the most recent tools for investigating the skin microbiota composition and microbe-skin relationships and perspectives regarding the challenges of skin microbiome manipulation. Video abstract.

Dysbiosis and Enhanced Beta-Defensin Production in Hair Follicles of Patients with Lichen Planopilaris and Frontal Fibrosing Alopecia

Despite their distinct clinical manifestation, frontal fibrosing alopecia (FFA) and lichen planopilaris (LPP) display similar histopathologic features. Aberrant innate immune responses to endogenous or exogenous triggers have been discussed as factors that could drive inflammatory cascades and the collapse of the stem cell niche. In this exploratory study, we investigate the bacterial composition of scalp skin and plucked hair follicles (HF) of patients with FFA, LPP and alopecia areata circumscripta (AAc), as well as healthy individuals, in relation to cellular infiltrates and the expression of defense mediators. The most abundant genus in lesional and non-lesional HFs of LPP and FFA patients was Staphylococcus, while Lawsonella dominated in healthy individuals and in AAc patients. We observed statistically significant differences in the ratio of Firmicutes to Actinobacteria between healthy scalp, lesional, and non-lesional sites of FFA and LPP patients. This marked dysbiosis in FFA and LPP in compartments close to the bulge was associated with increased HβD1 and HβD2 expression along the HFs from lesional sites, while IL-17A was increased in lesional HF from AAc patients. The data encourage further studies on how exogenous factors and molecular interactions across the HF epithelium could contribute to disease onset and propagation.

Human Skin Microbiome: Impact of Intrinsic and Extrinsic Factors on Skin Microbiota

The skin is the largest organ of the human body and it protects the body from the external environment. It has become the topic of interest of researchers from various scientific fields. Microorganisms ensure the proper functioning of the skin. Of great importance, are the mutual relations between such microorganisms and their responses to environmental impacts, as dysbiosis may contribute to serious skin diseases. Molecular methods, used for microorganism identification, allow us to gain a better understanding of the skin microbiome. The presented article contains the latest reports on the skin microbiota in health and disease. The review discusses the relationship between a properly functioning microbiome and the body's immune system, as well as the impact of internal and external factors on the human skin microbiome.

Characterization of the human skin resistome and identification of two microbiota cutotypes

BACKGROUND

The human skin microbiota is considered to be essential for skin homeostasis and barrier function. Comprehensive analyses of its function would substantially benefit from a catalog of reference genes derived from metagenomic sequencing. The existing catalog for the human skin microbiome is based on samples from limited individuals from a single cohort on reference genomes, which limits the coverage of global skin microbiome diversity.

RESULTS

In the present study, we have used shotgun metagenomics to newly sequence 822 skin samples from Han Chinese, which were subsequently combined with 538 previously sequenced North American samples to construct an integrated Human Skin Microbial Gene Catalog (iHSMGC). The iHSMGC comprised 10,930,638 genes with the detection of 4,879,024 new genes. Characterization of the human skin resistome based on iHSMGC confirmed that skin commensals, such as Staphylococcus spp, are an important reservoir of antibiotic resistance genes (ARGs). Further analyses of skin microbial ARGs detected microbe-specific and skin site-specific ARG signatures. Of note, the abundance of ARGs was significantly higher in Chinese than Americans, while multidrug-resistant bacteria ("superbugs") existed on the skin of both Americans and Chinese. A detailed analysis of microbial signatures identified Moraxella osloensis as a species specific for Chinese skin. Importantly, Moraxella osloensis proved to be a signature species for one of two robust patterns of microbial networks present on Chinese skin, with Cutibacterium acnes indicating the second one. Each of such "cutotypes" was associated with distinct patterns of data-driven marker genes, functional modules, and host skin properties. The two cutotypes markedly differed in functional modules related to their metabolic characteristics, indicating that host-dependent trophic chains might underlie their development.

CONCLUSIONS

The development of the iHSMGC will facilitate further studies on the human skin microbiome. In the present study, it was used to further characterize the human skin resistome. It also allowed to discover the existence of two cutotypes on the human skin. The latter finding will contribute to a better understanding of the interpersonal complexity of the skin microbiome. Video abstract.

New solution of beauty problem by Staphylococcus hominis: Relevance between skin microbiome and skin condition in healthy subject

BACKGROUND/AIMS

Recently, it was suggested that skin microbiome is related to some skin disease. The possibility of affecting the skin might be high, but there were few reports of the influence on the skin condition in healthy subjects. Our aim was to evaluate the relationship between skin condition and skin microbiome in healthy subjects.

METHODS

Experiment 1: 293 Japanese healthy women were divided into two groups, good skin properties and poor skin properties by 14 skin physiology parameter values on the cheek using noninvasive method. Differences of abundance of bacterial species on the cheek between the two groups were evaluated. Experiment 2: 11 Japanese healthy women were applied Staphylococcus hominis (S. hominis) on half-side of cheek for eight times in 1 month. Difference of change of physiology parameter values comparing to placebo side was evaluated.

RESULTS

Experiment 1: Multiple skin bacterial species were found to be significantly relevant in 14 physiology parameters. The abundance of S. hominis on the cheek with good skin properties group was significantly higher than poor skin properties group. Experiment 2: The application of S. hominis improved significantly the conspicuous pore number, melanin index, and the wrinkle count compared to placebo side.

CONCLUSION

We found many skin bacterial species that might improve the skin condition in healthy women. In particular, S. hominis might have the potential to improve multiple skin beauty problems.

Human Emissions of Size-Resolved Fluorescent Aerosol Particles: Influence of Personal and Environmental Factors

Human emissions of fluorescent aerosol particles (FAPs) can influence the biological burden of indoor air. Yet, quantification of FAP emissions from human beings remains limited, along with a poor understanding of the underlying emission mechanisms. To reduce the knowledge gap, we characterized human emissions of size-segregated FAPs (1-10 μm) and total particles in a climate chamber with low-background particle levels. We probed the influence of several personal factors (clothing coverage and age) and environmental parameters (level of ozone, air temperature, and relative humidity) on particle emissions from human volunteers. A material-balance model showed that the mean emission rate ranged 5.3-16 × 10⁶ fluorescent particles per person-h (0.30-1.2 mg per person-h), with a dominant size mode within 3-5 μm. Volunteers wearing long-sleeve shirts and pants produced 40% more FAPs relative to those wearing t-shirts and shorts. Particle emissions varied across the age groups: seniors (average age 70.5 years) generated 50% fewer FAPs compared to young adults (25.0 years) and teenagers (13.8 years). While we did not observe a measurable influence of ozone (0 vs 40 ppb) on human FAP emissions, there was a strong influence of relative humidity (34 vs 62%), with FAP emissions decreasing by 30-60% at higher humidity.

The Skin Interactome: A Holistic "Genome-Microbiome-Exposome" Approach to Understand and Modulate Skin Health and Aging

Higher demands on skin care cosmetic products for strong performance drive intense research to understand the mechanisms of skin aging and design strategies to improve overall skin health. Today we know that our needs and influencers of skin health and skin aging change throughout our life journey due to both extrinsic factors, such as environmental factors and lifestyle factors, as well as our intrinsic factors. Furthermore, we need to consider our microflora, a collection of micro-organisms such as bacteria, viruses, and fungi, which is a living ecosystem in our gut and on our skin, that can have a major impact on our health. Here, we are viewing a holistic approach to understand the collective effect of the key influencers of skin health and skin aging both reviewing how each of them impact the skin, but more importantly to identify molecular conjunction pathways of these different factors in order to get a better understanding of the integrated “genome-microbiome-exposome” effect. For this purpose and in order to translate molecularly the impact of the key influencers of skin health and skin aging, we built a digital model based on system biology using different bioinformatics tools. This model is considering both the positive and negative impact of our genome (genes, age/gender), exposome: external (sun, pollution, climate) and lifestyle factors (sleep, stress, exercise, nutrition, skin care routine), as well as the role of our skin microbiome, and allowed us in a first application to evaluate the effect of the genome in the synthesis of collagen in the skin and the determination of a suitable target for boosting pro-collagen synthesis. In conclusion, we have, through our digital holistic approach, defined the skin interactome concept, as an advanced tool to better understand the molecular genesis of skin aging and further develop a strategy to balance the influence of the exposome and microbiome to protect, prevent, and delay the appearance of skin aging signs and preserve good skin health condition. In addition, this model will aid in identifying and optimizing skin treatment options based on external triggers, as well as helping to design optimal treatments modulating the intrinsic pathways.

New Insights Into the Skin Microbial Communities and Skin Aging

Although it is well-known that human skin aging is accompanied by an alteration in the skin microbiota, we know little about how the composition of these changes during the course of aging and the effects of age-related skin microbes on aging. Using 16S ribosomal DNA and internal transcribed spacer ribosomal DNA sequencing to profile the microbiomes of 160 skin samples from two anatomical sites, the cheek and the abdomen, on 80 individuals of varying ages, we developed age-related microbiota profiles for both intrinsic skin aging and photoaging to provide an improved understanding of the age-dependent variation in skin microbial composition. According to the landscape, the microbial composition in the Children group was significantly different from that in the other age groups. Further correlation analysis with clinical parameters and functional prediction in each group revealed that high enrichment of nine microbial communities (i.e., Cyanobacteria, Staphylococcus, Cutibacterium, Lactobacillus, Corynebacterium, Streptococcus, Neisseria, Candida, and Malassezia) and 18 pathways (such as biosynthesis of antibiotics) potentially affected skin aging, implying that skin microbiomes may perform key functions in skin aging by regulating the immune response, resistance to ultraviolet light, and biosynthesis and metabolism of age-related substances. Our work re-establishes that skin microbiomes play an important regulatory role in the aging process and opens a new approach for targeted microbial therapy for skin aging.

Investigation of Age-Related Changes in the Skin Microbiota of Korean Women

The microbiota of human skin is influenced by host and environmental factors. To determine if chronological age influences the composition of the skin microbiota on the forehead and hands, 73 Korean women were sorted into one of three age groups: (1) 10-29 years (n = 24), (2) 30-49 years (n = 21), and (3) 50-79 years (n = 28). From the 73 women, 146 skin samples (two skin sites per person) were collected. 16S rRNA gene amplicon sequencing was then conducted to analyze the skin microbiota. The overall microbial distribution varied on the forehead but was similar on the hands across the three age groups. In addition, the composition of the skin microbiota differed between the forehead and hands. Commensal microbiota, such as Streptococcus, Staphylococcus, Cutibacterium, and Corynebacterium, which contribute to maintaining skin health via dominant occupation, were affected by increasing age on forehead and hand skin. Alpha diversity indices increased significantly with age on forehead skin. This study indicates that older people may be more susceptible to pathogenic invasions due to an imbalanced skin microbiota resulting from age-related changes. The results of our study may help develop new strategies to rebalance skin microbiota shifted during aging.

The Pathobiology of Skin Aging: New Insights into an Old Dilemma

Long considered both physiologic and inevitable, skin aging is a degenerative phenomenon whereby both intrinsic and environmental factors conspire to produce an authentic disease. The consequences of this disorder are many and varied, ranging from atrophy and fragility to defective repair to deficient immunity and vulnerability to certain infections. The pathobiologic basis for skin aging remains poorly understood. At a cellular level, stem cell dysfunction and attrition appear to be key events, and both genetic and epigenetic factors are involved in a complex interplay that over time results in deterioration of our main protective interface with the external environment. Past and current understanding of the cellular and molecular intricacies of skin aging provide a foundation for future approaches designed to thwart the aging phenotype. Herein, the authors provide a review of current insights into skin aging, including the mechanisms of skin aging, the role of stem cells in skin aging and the implications of skin aging for the microbiome and for the development of cancer. Conquest of the oft overlooked disease of skin aging should have broad implications that transcend the integument and inform novel approaches to retarding aging and age-related dysfunction in those internal organs that youthful skin was designed to envelop and safeguard.

Skin bacterial structure of young females in China: The relationship between skin bacterial structure and facial skin types

BACKGROUND

Skin microbiota are involved in the skin physiological functions and are also affected by the skin physiological characteristics.

OBJECTIVE

To better understand the skin microbial characteristics of facial cheek skin and the relationship with skin physiological characteristics.

METHODS

By bacterial 16S rRNA gene sequencing, the authors studied the facial cheek skin microbial characteristics of 85 cases of young women aged 18-25 years.

RESULTS

Healthy young woman's cheek skin bacterial composition was relatively stable. Dry skin has high bacterial diversity and richness, and oily skin has low bacterial diversity and richness. Cutibacterium was significantly enriched in oily skin and was significantly negatively correlated with other genera such as Streptococcus (r > 0.5). There were significant positive correlations among other genera of enrichment in dry and neutral skin such as Streptococcus and Rothia (r > 0.8). Skin sebum level was significantly negatively correlated with bacterial alpha diversity index. The combined abundance of Cutibacterium acnes and Staphylococcus epidermidis was significantly positively correlated with sebum secretion (r > 0.5).

CONCLUSIONS

The skin sebum secretion and bacterial interaction were the important factors driving the young females' cheek skin bacterial community structure.

Wound senescence: A functional link between diabetes and ageing?

Arguably, the two most important causes of pathological healing in the skin are diabetes and ageing. While these factors have historically been considered independent modifiers of the healing process, recent studies suggest that they may be mechanistically linked. The primary contributor to diabetic pathology is hyperglycaemia, which accelerates the production of advanced glycation end products, a characteristic of ageing tissue. Indeed, advanced age also leads to mild hyperglycaemia. Here, we discuss emerging literature that reveals a hitherto unappreciated link between cellular senescence, diabetes and wound repair. Senescent cells cause widespread destruction of normal tissue architecture in ageing and have been shown to be increased in chronic wounds. However, the role of senescence remains controversial, with several studies reporting beneficial effects for transiently induced senescence in wound healing. We recently highlighted a direct role for senescence in diabetic healing pathology, mediated by the senescence receptor, CXCR2. These findings suggest that targeting local tissue senescence may provide a therapeutic strategy applicable to a broad range of chronic wound types.

Characterization and Analysis of the Skin Microbiota in Rosacea: Impact of Systemic Antibiotics

Systemic antibiotics are extensively used to control the papules and pustules of rosacea. Hence, it is crucial to understand their impact on the rosacea skin microbiota which is thought to be perturbed. The purpose of this study was to compare the makeup and diversity of the skin microbiota in rosacea before and after taking oral antibiotics. We also compared the skin microbiota at baseline according to age and rosacea severity. A longitudinal cohort study was performed on 12 rosacea patients with papules/pustules and no recent use of oral and topical antimicrobials/retinoids. Patients were prescribed oral doxycycline, 100 mg, twice daily for six weeks. Skin areas on the cheek and nose were sampled for 16S ribosomal RNA gene sequencing at baseline, and after six weeks of doxycycline treatment. Eleven females and one male aged 20–79 (median 51) with a median Investigator’s Global Assessment score of 3 (moderate) were enrolled. At baseline, Staphylococcus epidermidis was the most dominant species followed by Cutibacterium acnes (formerly Propionibacterium acnes). In the 60 Over-age group, the prevalence of Cutibacterium acnes was lower than that of the 60 & Under-age group. Rosacea severity increased with age and was associated with a decrease in the relative abundance of Cutibacterium acnes and an increase of Snodgrassella alvi. Across all subjects, antibiotic treatment reduced clinical rosacea grades and was associated with an increase in the relative abundance of Weissella confusa (P = 0.008, 95% CI 0.13% to 0.61%). Bacterial diversity (alpha diversity) was not significantly altered by antibiotics treatment. Principal coordinates analysis showed mild clustering of samples by patient (ANOSIM, Analysis of Similarity, R = 0.119, P = 0.16) and scant clustering with treatment (ANOSIM, R = 0.002; P = 0.5). In conclusion, we believe that rosacea has a unique age-dependent characteristic (i.e., severity). Although we were not able to pinpoint a causative microbiota, our study provides a glimpse into the skin microbiota in rosacea and its modulation by systemic antibiotics.

Slowing Down Ageing: The Role of Nutrients and Microbiota in Modulation of the Epigenome

The human population is getting ageing. Both ageing and age-related diseases are correlated with an increased number of senescent cells in the organism. Senescent cells do not divide but are metabolically active and influence their environment by secreting many proteins due to a phenomenon known as senescence associated secretory phenotype (SASP). Senescent cells differ from young cells by several features. They possess more damaged DNA, more impaired mitochondria and an increased level of free radicals that cause the oxidation of macromolecules. However, not only biochemical and structural changes are related to senescence. Senescent cells have an altered chromatin structure, and in consequence, altered gene expression. With age, the level of heterochromatin decreases, and less condensed chromatin is more prone to DNA damage. On the one hand, some gene promoters are easily available for the transcriptional machinery; on the other hand, some genes are more protected (locally increased level of heterochromatin). The structure of chromatin is precisely regulated by the epigenetic modification of DNA and posttranslational modification of histones. The methylation of DNA inhibits transcription, histone methylation mostly leads to a more condensed chromatin structure (with some exceptions) and acetylation plays an opposing role. The modification of both DNA and histones is regulated by factors present in the diet. This means that compounds contained in daily food can alter gene expression and protect cells from senescence, and therefore protect the organism from ageing. An opinion prevailed for some time that compounds from the diet do not act through direct regulation of the processes in the organism but through modification of the physiology of the microbiome. In this review we try to explain the role of some food compounds, which by acting on the epigenetic level might protect the organism from age-related diseases and slow down ageing. We also try to shed some light on the role of microbiome in this process.

Microbiome Imbalances: An Overlooked Potential Mechanism in Chronic Nonhealing Wounds

Chronic nonhealing wounds are a severe burden to health care systems worldwide, causing millions of patients to have lengthy hospital stays, high health care costs, periods of unemployment, and reduced quality of life. Moreover, treating chronic nonhealing wounds effectively and reasonably in countries with limited medical resources can be extremely challenging. With many outstanding questions surrounding chronic nonhealing wounds, in this review, we offer changes to the microbiome as a potentially ignored mechanism important in the formation and treatment of chronic wounds. Our analysis helps bring a whole new understanding to wound formation and healing and provides a potential breakthrough in the treatment of chronic nonhealing wounds in the future.

A view to a kill? - Ambient bacterial load of frames and lenses of spectacles and evaluation of different cleaning methods

Surfaces with regular contact with the human body are typically contaminated with microorganisms and might be considered as fomites. Despite spectacles being widespread across populations, little is known about their microbial contamination. Therefore, we swab-sampled 11 worn spectacles within a university setting as well as 10 worn spectacles in a nursing home setting. The microbial load was determined by aerobic cultivation. All spectacles were found to be contaminated with bacteria, with nose pads and ear clips having the highest density, i.e. at sites with direct skin contact. Summed over all sites, the median microbial load of the university spectacles (1.4 ± 10.7 x 10(3) CFU cm-2) did not differ significantly from the spectacles tested in the nursing home (20.8 ± 39.9 x 10(3) CFU cm-2). 215 dominant bacterial morphotypes were analyzed by MALDI biotyping. 182 isolates could be assigned to 10 genera, with Staphylococcus being the most common. On genus-level, bacterial diversity was greater on nursing home spectacles (10 genera) compared to the university environment (2 genera). Four cleaning methods were investigated using lenses artificially contaminated with Escherichia coli, Micrococcus luteus, a 1:2 mixture of E. coli and M. luteus, and Staphylococcus epidermidis (the dominant isolate in our study), respectively. Best cleaning results (99% -100% median germ reduction) were obtained using impregnated wipes; dry cleaning was less effective (85% -90% median germ reduction). Finally, 10 additional worn university spectacles were cleaned with wipes impregnated with an alcohol-free cleaning solution before sampling. The average bacterial load was significantly lower (0.09 ± 0.49 x 10(3) CFU cm-2) compared to the uncleaned university spectacles previously investigated. Spectacles are significantly contaminated with bacteria of mostly human skin origin-including significant amounts of potentially pathogenic ones and may contribute to eye infections as well as fomites in clinical environments.

Enhancing Skin Health: By Oral Administration of Natural Compounds and Minerals with Implications to the Dermal Microbiome

The history of cosmetics goes back to early Egyptian times for hygiene and health benefits while the history of topical applications that provide a medicinal treatment to combat dermal aging is relatively new. For example, the term cosmeceutical was first coined by Albert Kligman in 1984 to describe topical products that afford both cosmetic and therapeutic benefits. However, beauty comes from the inside. Therefore, for some time scientists have considered how nutrition reflects healthy skin and the aging process. The more recent link between nutrition and skin aging began in earnest around the year 2000 with the demonstrated increase in peer-reviewed scientific journal reports on this topic that included biochemical and molecular mechanisms of action. Thus, the application of: (a) topical administration from outside into the skin and (b) inside by oral consumption of nutritionals to the outer skin layers is now common place and many journal reports exhibit significant improvement for both on a variety of dermal parameters. Therefore, this review covers, where applicable, the history, chemical structure, and sources such as biological and biomedical properties in the skin along with animal and clinical data on the oral applications of: (a) collagen, (b) ceramide, (c) β-carotene, (d) astaxanthin, (e) coenzyme Q10, (f) colostrum, (g) zinc, and (h) selenium in their mode of action or function in improving dermal health by various quantified endpoints. Lastly, the importance of the human skin microbiome is briefly discussed in reference to the genomics, measurement, and factors influencing its expression and how it may alter the immune system, various dermal disorders, and potentially be involved in chemoprevention.