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Medecine Sciences : M/S Dec 2020One of the major challenges of the 21 century is the fight against aging, defined as a set of physiological mechanisms altering the physical and intellectual capacities... (Review)
Review
One of the major challenges of the 21 century is the fight against aging, defined as a set of physiological mechanisms altering the physical and intellectual capacities of human beings. Aging of the skin is only one visible part of this process. It is associated with major healing defects linked in part to the alteration of the biomechanical properties of skin cells, mainly dermal fibroblasts. The immune system, another key component in maintaining skin homeostasis and the efficient healing of wounds, also suffers the effects of time: the consequent skin immunosenescence would limit the anti-infectious and vaccine response, while promoting a pro-tumor environment. The main skin damages due to aging, whether intrinsic or extrinsic, will be detailed before listing the effective anti-aging strategies to combat age-related dermal and epidermal stigmas.
Topics: Aging; Animals; Cellular Senescence; Drugs, Investigational; Epidermis; Humans; Skin; Skin Aging; Therapies, Investigational; Wound Healing
PubMed: 33296633
DOI: 10.1051/medsci/2020232 -
Nature Reviews. Microbiology Apr 2011The skin is the human body's largest organ, colonized by a diverse milieu of microorganisms, most of which are harmless or even beneficial to their host. Colonization is... (Review)
Review
The skin is the human body's largest organ, colonized by a diverse milieu of microorganisms, most of which are harmless or even beneficial to their host. Colonization is driven by the ecology of the skin surface, which is highly variable depending on topographical location, endogenous host factors and exogenous environmental factors. The cutaneous innate and adaptive immune responses can modulate the skin microbiota, but the microbiota also functions in educating the immune system. The development of molecular methods to identify microorganisms has led to an emerging view of the resident skin bacteria as highly diverse and variable. An enhanced understanding of the skin microbiome is necessary to gain insight into microbial involvement in human skin disorders and to enable novel promicrobial and antimicrobial therapeutic approaches for their treatment.
Topics: Adaptive Immunity; Humans; Immunity, Innate; Metagenome; Skin; Skin Diseases, Infectious
PubMed: 21407241
DOI: 10.1038/nrmicro2537 -
International Journal of Molecular... Apr 2019The skin is a complex organ that has devised numerous strategies, such as physical, chemical, and microbiological barriers, to protect the host from external insults. In... (Review)
Review
The skin is a complex organ that has devised numerous strategies, such as physical, chemical, and microbiological barriers, to protect the host from external insults. In addition, the skin contains an intricate network of immune cells resident to the tissue, crucial for host defense as well as tissue homeostasis. In the event of an insult, the skin-resident immune cells are crucial not only for prevention of infection but also for tissue reconstruction. Deregulation of immune responses often leads to impaired healing and poor tissue restoration and function. In this review, we will discuss the defensive components of the skin and focus on the function of skin-resident immune cells in homeostasis and their role in wound healing.
Topics: Animals; Biomarkers; Disease Susceptibility; Humans; Immune System; Microbiota; Skin; Skin Physiological Phenomena; Wound Healing
PubMed: 31013709
DOI: 10.3390/ijms20081811 -
Biomolecules Apr 2015Oxidative stress in skin plays a major role in the aging process. This is true for intrinsic aging and even more for extrinsic aging. Although the results are quite... (Review)
Review
Oxidative stress in skin plays a major role in the aging process. This is true for intrinsic aging and even more for extrinsic aging. Although the results are quite different in dermis and epidermis, extrinsic aging is driven to a large extent by oxidative stress caused by UV irradiation. In this review the overall effects of oxidative stress are discussed as well as the sources of ROS including the mitochondrial ETC, peroxisomal and ER localized proteins, the Fenton reaction, and such enzymes as cyclooxygenases, lipoxygenases, xanthine oxidases, and NADPH oxidases. Furthermore, the defense mechanisms against oxidative stress ranging from enzymes like superoxide dismutases, catalases, peroxiredoxins, and GSH peroxidases to organic compounds such as L-ascorbate, α-tocopherol, beta-carotene, uric acid, CoQ10, and glutathione are described in more detail. In addition the oxidative stress induced modifications caused to proteins, lipids and DNA are discussed. Finally age-related changes of the skin are also a topic of this review. They include a disruption of the epidermal calcium gradient in old skin with an accompanying change in the composition of the cornified envelope. This modified cornified envelope also leads to an altered anti-oxidative capacity and a reduced barrier function of the epidermis.
Topics: Humans; Oxidative Stress; Skin; Skin Aging
PubMed: 25906193
DOI: 10.3390/biom5020545 -
The Journal of Investigative Dermatology Jun 2017Human skin contains an abundant and diverse population of microbial organisms. Many of these microbes inhabit follicular structures of the skin. Furthermore, numerous... (Review)
Review
Human skin contains an abundant and diverse population of microbial organisms. Many of these microbes inhabit follicular structures of the skin. Furthermore, numerous studies have shown that the interaction of some members of the skin microbiome with host cells will result in changes in cell function. However, estimates of the potential for the microbiome to influence human health through skin have ignored the inner follicular surface, and therefore vastly underestimated the potential of the skin microbiome to have a systemic effect on the human body. By calculating the surface area of follicular and the interfollicular epithelial surface it is shown that skin provides a vast interface for interactions with the microbiome.
Topics: Bacterial Adhesion; Epidermis; Humans; Microbiota; Skin
PubMed: 28395897
DOI: 10.1016/j.jid.2016.11.045 -
Journal of the European Academy of... Aug 2019Indoor and outdoor airborne pollutants modify our environment and represent a growing threat to human health worldwide. Airborne pollution effects on respiratory and... (Review)
Review
Indoor and outdoor airborne pollutants modify our environment and represent a growing threat to human health worldwide. Airborne pollution effects on respiratory and cardiac health and diseases have been well established, but its impact on skin remains poorly described. Nonetheless, the skin is one of the main targets of pollutants, which reach the superficial and deeper skin layers by transcutaneous and systemic routes. In this review, we report the outcomes of basic and clinical research studies monitoring pollutant levels in human tissues including the skin and hair. We present a current understanding of the biochemical and biophysical effects of pollutants on skin metabolism, inflammatory processes and oxidative stress, with a focus on polyaromatic hydrocarbons and ground-level ozone that are widespread outdoor pollutants whose effects are mostly studied. We reviewed the literature to report the clinical effects of pollutants on skin health and skin ageing and their impact on some chronic inflammatory skin diseases. We also discuss the potential interactions of airborne pollutants with either ultraviolet radiation or human skin microbiota and their specific impact on skin health.
Topics: Air Pollutants; Humans; Microbiota; Oxidative Stress; Skin; Skin Aging; Ultraviolet Rays
PubMed: 30897234
DOI: 10.1111/jdv.15583 -
Stem Cell Research & Therapy Mar 2019Normal wound healing is a dynamic and complex multiple phase process involving coordinated interactions between growth factors, cytokines, chemokines, and various cells.... (Review)
Review
Normal wound healing is a dynamic and complex multiple phase process involving coordinated interactions between growth factors, cytokines, chemokines, and various cells. Any failure in these phases may lead wounds to become chronic and have abnormal scar formation. Chronic wounds affect patients' quality of life, since they require repetitive treatments and incur considerable medical costs. Thus, much effort has been focused on developing novel therapeutic approaches for wound treatment. Stem-cell-based therapeutic strategies have been proposed to treat these wounds. They have shown considerable potential for improving the rate and quality of wound healing and regenerating the skin. However, there are many challenges for using stem cells in skin regeneration. In this review, we present some sets of the data published on using embryonic stem cells, induced pluripotent stem cells, and adult stem cells in healing wounds. Additionally, we will discuss the different angles whereby these cells can contribute to their unique features and show the current drawbacks.
Topics: Animals; Cell- and Tissue-Based Therapy; Humans; Skin; Stem Cells; Tissue Engineering; Wound Healing
PubMed: 30922387
DOI: 10.1186/s13287-019-1212-2 -
Nutrients Jan 2019Skin serves as the first protective line and barrier of the body. Like many other organs, skin can be affected by several disorders in response to external factors such... (Review)
Review
Skin serves as the first protective line and barrier of the body. Like many other organs, skin can be affected by several disorders in response to external factors such as pathogens, ultraviolet light, and pollution, as well as endogenous alterations related to aging and/or oxidative stress disturbance. Researchers have reported new insights into how skin cells are altered in response to caloric restriction diets in mammals. One of the most well-known caloric restriction diets is the Ramadan intermittent fasting, which is a radical change in the diet plan of practitioners for the period of one lunar month. Ramadan fasting represents the fourth of the five pillars of the Islamic creed. Even though infirm individuals are waived to take part in this religious duty, patients with various health problems, including those with different skin disorders, might choose to share this event with peers and family members. No standardized protocols or guidelines exist, however, to advise their physicians on the proper management of their patients' condition during fasting. With an increasing Muslim population living in Western countries, this topic has started to draw substantial attention, not only of Middle-Eastern physicians, but also of clinicians in the West. For this purpose, we carried out a comprehensive overview on the topic. Our main findings are that: (1) there is a strong need for evidence-based suggestions and guidance. Literature on the impact of the Ramadan fasting, as well as of other kinds of fasting, on skin diseases is scarce and of poor quality, as well as the information available from the Internet; (2) patients willing to fast should be advised about the importance of taking proper treatments or consider alternative options including administration of trans-dermal/topical drugs, as they are permitted during daylight hours. Further, non-compliance has important, clinical and economic implications for an effective patient management.
Topics: Animals; Biomedical Research; Fasting; Humans; Islam; Mice; Rats; Skin; Skin Diseases; Skin Physiological Phenomena
PubMed: 30678053
DOI: 10.3390/nu11020249 -
BMC Biology Jun 2019Use of skin personal care products on a regular basis is nearly ubiquitous, but their effects on molecular and microbial diversity of the skin are unknown. We evaluated...
BACKGROUND
Use of skin personal care products on a regular basis is nearly ubiquitous, but their effects on molecular and microbial diversity of the skin are unknown. We evaluated the impact of four beauty products (a facial lotion, a moisturizer, a foot powder, and a deodorant) on 11 volunteers over 9 weeks.
RESULTS
Mass spectrometry and 16S rRNA inventories of the skin revealed decreases in chemical as well as in bacterial and archaeal diversity on halting deodorant use. Specific compounds from beauty products used before the study remain detectable with half-lives of 0.5-1.9 weeks. The deodorant and foot powder increased molecular, bacterial, and archaeal diversity, while arm and face lotions had little effect on bacterial and archaeal but increased chemical diversity. Personal care product effects last for weeks and produce highly individualized responses, including alterations in steroid and pheromone levels and in bacterial and archaeal ecosystem structure and dynamics.
CONCLUSIONS
These findings may lead to next-generation precision beauty products and therapies for skin disorders.
Topics: Adult; Cosmetics; Female; Humans; Male; Microbiota; Skin; Skin Care
PubMed: 31189482
DOI: 10.1186/s12915-019-0660-6 -
Nature Dec 2013Fibroblasts are the major mesenchymal cell type in connective tissue and deposit the collagen and elastic fibres of the extracellular matrix (ECM). Even within a single...
Fibroblasts are the major mesenchymal cell type in connective tissue and deposit the collagen and elastic fibres of the extracellular matrix (ECM). Even within a single tissue, fibroblasts exhibit considerable functional diversity, but it is not known whether this reflects the existence of a differentiation hierarchy or is a response to different environmental factors. Here we show, using transplantation assays and lineage tracing in mice, that the fibroblasts of skin connective tissue arise from two distinct lineages. One forms the upper dermis, including the dermal papilla that regulates hair growth and the arrector pili muscle, which controls piloerection. The other forms the lower dermis, including the reticular fibroblasts that synthesize the bulk of the fibrillar ECM, and the preadipocytes and adipocytes of the hypodermis. The upper lineage is required for hair follicle formation. In wounded adult skin, the initial wave of dermal repair is mediated by the lower lineage and upper dermal fibroblasts are recruited only during re-epithelialization. Epidermal β-catenin activation stimulates the expansion of the upper dermal lineage, rendering wounds permissive for hair follicle formation. Our findings explain why wounding is linked to formation of ECM-rich scar tissue that lacks hair follicles. They also form a platform for discovering fibroblast lineages in other tissues and for examining fibroblast changes in ageing and disease.
Topics: Adipocytes; Animals; Cell Lineage; Dermis; Female; Fibroblasts; Hair Follicle; In Vitro Techniques; Male; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Transgenic; Muscle, Smooth; Skin; Wound Healing; beta Catenin
PubMed: 24336287
DOI: 10.1038/nature12783