Inflammaging and the Skin

Evidence that the aryl hydrocarbon receptor orchestrates oxinflammatory responses and contributes to airborne particulate matter-induced skin aging

Exposure to airborne particulate matter (PM) is a substantial threat to public health, contributing to respiratory, cardiovascular, and skin-related diseases. Population-based studies strongly indicate that chronic exposure to airborne PM, especially combustion-derived PM2.5, accelerates skin aging and thus reduces the quality of life of those affected. There is increasing evidence that especially PM-bound polycyclic aromatic hydrocarbons (PAHs) critically contribute to the clinical manifestation of skin aging, i.e. the development of lentigines/pigment spots and coarse wrinkles. PAHs harm human skin primarily by activating the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor amongst others involved in orchestrating xenobiotic metabolism and immune responses. In this review, we summarize the available population-based data linking particulate air pollution exposure to skin aging. We explain in detail how PAH-rich PM induces the formation of oxidative stress, the release of pro-inflammatory mediators, the expression extracellular matrix degrading metalloproteases, and melanin synthesis, in an AHR-dependent manner, and how these events may culminate in the development of pigment spots and wrinkles, respectively. We also review the current data on the interaction of airborne PM with another factor of the skin aging exposome that exerts its deleterious effects in part through AHR-dependent signaling pathways, namely solar ultraviolet radiation.

Dysregulation of autophagy during photoaging reduce oxidative stress and inflammatory damage caused by UV

Photoaging, the premature aging of skin due to chronic ultraviolet (UV) exposure, is a growing concern in dermatology and cosmetic science. While UV radiation is known to induce DNA damage, oxidative stress, and inflammation in skin cells, recent research unveils a promising countermeasure: autophagy. This review explores the intricate relationship between autophagy and photoaging, highlighting how this cellular recycling process can mitigate UV-induced damage. We begin by examining the differential impacts of UVA and UVB radiation on skin cells and the role of oxidative stress in accelerating photoaging. Next, we delve into the molecular mechanisms of autophagy, including its various forms and regulatory pathways. Central to this review is the discussion of autophagy's protective functions, such as the clearance of damaged organelles and proteins, and its role in maintaining genomic integrity. Furthermore, we address the current challenges in harnessing autophagy for therapeutic purposes, including the need for selective autophagy inducers and a deeper understanding of its context-dependent effects. By synthesizing recent advancements and proposing future research directions, this review underscores the potential of autophagy modulation as a novel strategy to prevent and treat photoaging. This comprehensive analysis aims to inspire further investigation into autophagy-based interventions, offering new hope for preserving skin health in the face of environmental stressors.

Potential Role of Dietary Antioxidants During Skin Aging

The skin is the largest organ of the human body in contact with the outside world. Different are its functions: body temperature regulation, mechanical barrier, coating, and sensory activity are just to name a few. Like any other part of the human organism, it too undergoes the phenomenon of aging, a complex biological process classified as chronological aging. Although this is a natural and inevitable physiological process, certain external factors have been shown to have an important impact. One of these, much discussed in recent years, is diet. The relevance of diet to the clinical features of skin aging, particularly the biochemical and histological changes that occur in it, is now well established. Lately, there has been a growing focus on which foods can be considered skin-friendly and which cannot. Açai berries, Moringa oleifera, and spirulina are just some of the emerging nutrients that counteract skin aging because of their potent antioxidant properties. Conversely, foods high in trans-fatty acids, refined sugars are related to accelerated skin aging as they are associated with the production of advanced glycation end products. Due to the interest generated in recent years on the subject, a subspecialty of anti-aging medicine called "nutricosmetics" has even emerged. This review aims to highlight the studies emerging in the last five years regarding what can be considered "skin-friendly" foods in contrast to what can be considered "skin-unfriendly" habits, taking into consideration studies regarding the innovations recently developed in terms of nutrients and skin aging strategies.

Magnolin Mitigates Skin Ageing Through the CXCL10/p38 Signalling Pathway

Skin ageing accelerates systemic ageing and impairs the body's disease resistance. Inflammaging is a significant contributor to skin ageing. However, the mechanism by which inflammatory factors contribute to skin ageing remains unclear. We conducted screenings and identified CXC motif chemokine ligand 10 (CXCL10) as an inducer of skin ageing, which can be effectively inhibited by magnolin extracted from Magnolia biondii flower. Our results show that CXCL10 not only enhances beta-galactosidase (β-gal) activity but also upregulates the expression of p21/p16, along with matrix metalloproteinases (MMP1, MMP9 and MMP10), through activation of the C-X-C motif chemokine receptor 3 (CXCR3) in human primary fibroblasts. These findings suggest that CXCL10 drives skin ageing by inducing cellular senescence and extracellular matrix degradation. Importantly, treatment with magnolin significantly mitigates skin ageing phenotypes induced by CXCL10 via the p38 signalling pathway. Furthermore, our study demonstrates that magnolin significantly mitigates UV-induced skin ageing in ex vivo human skin samples as well as on human facial skin. This study provides insight into the role of chemokine CXCL10 in promoting inflammaging and proposes an innovative approach for preventing and treating skin ageing.

Exploring melatonin's signalling pathways in the protection against age-related skin deterioration

Melatonin, renowned for regulating sleep-wake cycles, also exhibits notable anti-aging properties for the skin. Synthesized in the pineal gland and various tissues including the skin, melatonin's efficacy arises from its capacity to combat oxidative stress and shield the skin from ultraviolet (UV)-induced damage. Moreover, it curbs melanin production, thereby potentially ameliorating hyperpigmentation. The presence of melatonin receptors in diverse skin cell types and its documented ability to enhance skin tone, hydration, and texture upon topical administration underscores its promise as an anti-aging agent. Melatonin's protective effects likely emanate from its multifaceted characteristics, encompassing antioxidant, anti-inflammatory, and immunomodulatory functions, as well as its influence on collagen synthesis and mitochondrial activity. Chronic inflammation and oxidative stress initiate a detrimental feedback loop. Reactive oxygen species (ROS), notorious for damaging cellular structures, provoke immune responses by oxidizing vital molecules and activating signaling proteins. This triggers heightened expression of inflammatory genes, perpetuating the cycle. Such dysregulation significantly compromises the body's resilience against infections and other health adversities. This study embarks on an exploration of the fundamental signaling pathways implicated in skin aging. Furthermore, it delves into the therapeutic potential of melatonin and its anti-aging attributes within the realm of skin health.

Phenotype-endotype relationship in elderly atopic dermatitis and effects of dupilumab therapy: prospective study

Atopic dermatitis is a chronic inflammatory systemic disease that can persist or start in adulthood, even in elderly age, with several clinical phenotypes. The aim of this study was to evaluate the relationship between phenotype and endotype in elderly patients, and the long-term effects of dupilumab on molecular signature in these patients. A total of 50 elderly patients had been treated with dupilumab during the follow up period. Regarding effectiveness parameters, mean EASI score at Week 0 was 25.12 ± 4.23 and significantly reduced to 2.42 ± 3.15 at Week 52 (p < 0.05). Regarding safety, none of the registered adverse events led to the discontinuation of dupilumab therapy. Moreover, after 52 weeks of dupilumab treatment, Th2 cytokines expression was decreased, with IL-13 and IL-31 downregulated in both patient groups at Week 52, at both gene and protein levels when compared with Week 0. Our data also revealed a significant increase in both IL-4 gene expression and protein production at Week 52 when compared with Week 0. Unexpectedly, our results also revealed that IL-22 cutaneous expression was significantly increased, while circulating levels were decreased at Week 52 when compared to Week 0. In conclusion, our results highlight the effectiveness of dupilumab at a late time point as Week 52. Of note, a dumping of the Th2- and Th17- immune response at both systemic and in situ level and a possible remodelling role of IL-22 in the skin is suggested.

Protective effects of Rosa roxburghii Tratt. extract against UVB-induced inflammaging through inhibiting the IL-17 pathway

Chronic inflammation is a critical mechanism contributing to the aging process; however, research specifically addressing chronic inflammation in skin biology remains limited. This study investigates the protective mechanism of Rosa roxburghii Tratt. (RRT) extract against UVB-induced inflammaging. RRT extract effectively reduces the secretion of IL-6, IL-1α, TNF-α, and PGE2 in keratinocytes. Additionally, it attenuates UVB-induced IL-17 pathway activation by downregulating IL-17RA, c-Fos, and c-Jun protein levels, as well as the gene expression of IL-17RA, TRAF6, HSP90, and IKKγ. Co-culturing human foreskin fibroblasts (HFF) with inflammatory factors secreted by UVB-exposed keratinocytes reveals that these factors significantly reduce mitochondrial membrane potential and mitochondrial reactive oxygen species (ROS), thereby promoting aging in HFF. The anti-inflammaging effects of RRT extract are achieved through the reduction of β-galactosidase activity, targeting of the TGF-β1-Smad2/3 signaling pathway, upregulation of COL1A1 expression, and reduction of senescence-associated secretory phenotype secretion. This study provides a novel perspective and robust scientific foundation for exploring mechanisms of skin aging and potential therapeutic interventions.

Bioactive Substances and Skin Health: An Integrative Review from a Pharmacy and Nutrition Perspective

The skin is one of the largest and most important organs of our body. There are numerous factors that are related to skin health, including lifestyle factors, nutrition, or skin care. Bioactive substances from plant and marine extracts play a key role in skin health. The aim of this research was to compile the main evidence on skin and bioactive substances. An integrative review was performed, reporting the main findings according to PRISMA (2020). Thirteen search equations were developed. After the applications of the equations and the process of screening and selection of articles, 95 references were compiled. The main results related to bioactive compounds were classified into food-derived components, nutraceuticals, symbiotics, active substances of marine origin, and substances from plant extracts). There are several factors that indicate that the use of bioactive compounds are interesting for skin health, highlighting some dietary nutrients, substances obtained from plant extracts and metabolites of marine origin that, showing anti-inflammatory and antimicrobial effects, are related to the improvement of some skin conditions or are active principles for cosmetics.

The role of NRF2 transcription factor in inflammatory skin diseases

The skin is the body's largest organ and performs several vital functions, such as controlling the movement of essential substances while protecting against external threats. Although mainly composed of keratinocytes (KCs), the skin also contains a complex network of immune cells that play a critical role in host defense and maintaining skin homeostasis. KCs proliferate in the basal layer of the epidermis and undergo differentiation, altering their functional and phenotypic characteristics. These differentiation steps are crucial for the stratification of the epidermis and the formation of the stratum corneum, ensuring the skin barrier's functions. Exposure to UV, environmental pollutants, or chemicals can lead to an overproduction of reactive species of oxygen (ROS), leading to oxidative stress. To ensure redox homeostasis and prevent damage resulting from the formation of ROS, the skin has an extensive network of antioxidant defense systems, mainly orchestrated by the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway. Indeed, Nrf2 induces the expression of detoxification and antioxidant enzymes and suppresses inductions of pro-inflammatory cytokine genes. In this context, Nrf2 is critical in preserving skin functions such as epidermal differentiation, regulating skin immunity, and managing environmental stresses. Besides, this pathway plays an important role in the pathogenesis of common inflammatory skin diseases such as allergic contact dermatitis, atopic dermatitis, and psoriasis. Therefore, the present review highlights the crucial role of Nrf2 in KCs for maintaining skin homeostasis and regulating skin immunity, as well as its contribution to the pathophysiology of inflammatory skin diseases. Finally, a particular emphasis will be placed on the therapeutic potential of targeting the Nrf2 pathway to alleviate symptoms of these inflammatory skin disorders.

Effects of rice fermentation and its bioactive components on UVA-induced oxidative stress and senescence in dermal fibroblasts

Photoaging, caused by ultraviolet (UV) radiation, is characterized by the senescence of skin cells and reduction of collagens. Although rice fermentation is widely used in the cosmetics, its impact on skin photoaging is still not well understood. Herein, we investigated the possible effectiveness of Maifuyin, a fermented rice product, and its components, succinic acid (SA), and choline, for safeguarding UVA-exposed human dermal fibroblasts (HDFs) against photoaging. In this study, the effects of Maifuyin, SA, and choline on UVA-induced cell death and senescence in fibroblasts were evaluated in cell counting kit-8 (CCK-8), expression of β-galactosidase (β-GAL), and matrix metalloproteinases (MMP)-1. To identify oxidative stress, the investigation focused on reactive oxygen species, glutathione, superoxide dismutase, and malondialdehyde. Additionally, a mRNA sequencing technology (RNA-seq) was applied to study the underlying mechanisms of these components on UVA-induced photoaging. Meanwhile, the level of C-X-C motif chemokine ligand 2 (CXCL2) in the cell supernatant was confirmed to assess the autocrine chemokine level. To reassess the involvement of CXCL2, the expression of β-GAL was evaluated in fibroblasts treated with or without CXCL2. The results indicated that 1 mg/mL Maifuyin and SA inhibited UVA-induced senescence in fibroblasts, MMP-1 expression, and oxidative damage. The RNA-seq revealed 1 mg/mL Maifuyin and SA might be recruited chemokine CXCLs to inhibit MMPs production and fibroblast senescence via TNFα, MAPK, and NF-κB pathways. ELISA results showed a significant reduction of autocrine CXCL2 in UVA-irradiated HDFs by pretreating Maifuyin and SA. The β-GAL staining assay revealed that CXCL2 treatment increased β-GAL activity, while the administration of Maifuyin and SA counteracted this effect in HDFs. These results highlighted the potential use of Maifuyin and SA as promising candidates for anti-photoaging applications.

Senescence in the ageing skin: a new focus on mTORC1 and the lysosome

Ageing is defined as the progressive loss of tissue function and regenerative capacity and is caused by both intrinsic factors i.e. the natural accumulation of damage, and extrinsic factors i.e. damage from environmental stressors. Cellular senescence, in brief, is an irreversible exit from the cell cycle that occurs primarily in response to excessive cellular damage, such as from ultraviolet (UV) exposure and oxidative stress, and it has been comprehensively demonstrated to contribute to tissue and organismal ageing. In this review, we will focus on the skin, an organ which acts as an essential protective barrier against injury, insults, and infection. We will explore the evidence for the existence and contribution of cellular senescence to skin ageing. We discuss the known molecular mechanisms driving senescence in the skin, with a focus on the dysregulation of the master growth regulator, mechanistic Target of Rapamycin Complex 1 (mTORC1). We explore the interplay of dysregulated mTORC1 with lysosomes and how they contribute to senescence phenotypes.

The p53-miR17 family-Rankl axis bridges liver-bone communication

Our study elucidates the crucial role of the liver in bone homeostasis through the p53-miR17 family (miR17-miR20/miR20-miR106/miR93-miR106)-Rankl axis. We demonstrate the enhanced hepatocyte Rankl expression in inflammaging conditions, such as aging, ovariectomized (OVX) mice, and elderly humans. Mice with hepatocyte-specific Rankl deletion exhibit significant resistance to bone mass loss associated with aging, lipopolysaccharide (LPS)-induced inflammation, or estrogen deficiency, compared with controls. Our study highlights hepatocytes as the primary source of Rankl in the liver and serum under these conditions. We identify the p53-miR17 family axis as a crucial regulator for hepatocyte Rankl expression, with p53 inhibiting the miR17 family transcription. Through bioinformatics analysis and in vitro validation, we identify Rankl mRNA as a direct target of the miR17 family. Targeting this axis via CasRx-mediated mRNA editing or miRNA interference significantly attenuates bone mass loss in mice. Our investigation underscores the pivotal significance and therapeutic potential of modulating the p53-miR17 family-Rankl axis in the treatment of inflammaging-associated osteoporosis.

Non-Invasive Imaging for the Evaluation of a New Oral Supplement in Skin Aging: A Case-Controlled Study

BACKGROUND

Skin aging represents a para-physiological process related to metabolic imbalances, inflammation, proliferative responses, and oxidative stress. Ending the cycle of inflammation, and oxidative stress represents a way to slow the effects of aging.

STUDY OBJECTIVE

The aim of our study was to evaluate the benefits of supplements with an herbal mixture based on Venerinase and B-group vitamins, Zinc, and Magnesium in preventing/reducing photoaging by means of objective quantitative analysis of visual skin features obtained by VISIA 2D and stroma and vascular characteristics measured by Optical Coherence Tomography (OCT).

METHODS

A prospective clinical study was conducted in 40 participants. They were randomized 1:1 to receive the supplement (Giovina) or placebo. Assessments were conducted at Baseline (T0), after 2 months (T1), and after 4 months (T2). The primary endpoint was to obtain a significant improvement in facial photo/chrono-aging in the treatment arm, as assessed through the evaluation of the Griffith scale. Secondary endpoints were to assess significant changes in skin aging objective features (VISIA) and Optical Coherence Tomography (OCT) parameters.

RESULTS

The treated group showed a significant reduction in the mean Griffith scale score from 4.5 at baseline to 3.76 at T2 (4 months) (p = 0.001). A significant decrease in red areas and a borderline significant reduction in the number of wrinkles have been shown by skin aging objective feature calculation on VISIA 2D photographs. OCT analysis showed a borderline significant reduction in collagen density.

CONCLUSIONS

The decrease in vascular pattern and collagen density suggests an anti-inflammatory effect with a potential stromal remodeling in the treated group. This seems to be correlated to the reduction in wrinkles and facial redness.

TFC-1326 Compound Reduces Clinical Signs of Skin Aging. Evidence From In Vitro Human Adipose and Skin Models and Pilot Clinical Trial

BACKGROUND

Anti-freeze Glycoproteins (AFGPs) were described to preserve biological materials and protect them from different stresses.

AIMS

The effects of a synthetic anti-freeze glycoprotein-based compound, TFC-1326, on human skin quality and its biological actions were studied.

METHODS

The effects of various concentrations of TFC-1326 on the biology of human preadipocytes, differentiated in the proinflammatory microenvironment, and on human fibroblasts grown in coculture with human mature adipocytes or monocultured in stress conditions were investigated in, in vitro studies. Additionally, the efficacy of a 1% TFC-1326 topical cream was evaluated in a clinical investigation on the skin biology and appearance of 20 women aged between 40 and 65 years throughout 84 days of application.

RESULTS

The in vitro studies revealed that TFC-1326 mitigated the deleterious effects of a proinflammatory cytokine cocktail produced by human macrophages, by restoring preadipocyte adipogenic capacity and by reducing their fibroinflammatory state. TFC-1326 also stimulated the proliferative capacity of dermal fibroblasts co-cultured with mature adipocytes as well as their production of hyaluronic acid and procollagen type I, while decreasing IL6 secretion and increasing fibroblast viability. Furthermore, daily 1% TFC-1326 topical cream application, measurably improved skin radiance and laxity, as well as skin density. Finally, significant reductions of the volume and depth of the crow's feet wrinkles were also observed.

CONCLUSIONS

The compound TFC-1326 significantly improved the physiological appearance and cellular functions of aging skin.

Deciphering the role of skin aging in pigmentary disorders

Skin aging is a complex biological process involving intrinsic and extrinsic factors. Skin aging contains alterations at the tissue, cellular, and molecular levels. Currently, there is increasing evidence that skin aging occurs not only in time-dependent chronological aging but also plays a role in skin pigmentary disorders. This review provides an in-depth analysis of the impact of skin aging on different types of pigmentary disorders, including both hyperpigmentation disorders such as melasma and senile lentigo and hypopigmentation disorders such as vitiligo, idiopathic guttate hypomelanosis and graying of hair. In addition, we explore the mechanisms of skin aging on pigmentation regulation and suggest several potential therapeutic approaches for skin aging and aging-related pigmentary disorders.

Sustainable Skincare Innovation: Cork Powder Extracts as Active Ingredients for Skin Aging

Background: An emerging practice within the concept of circular beauty involves the upcycling of agro-industrial by-products. Cork processing, for instance, yields by-products like cork powder, which presents an opportunity to create value-added cosmetic ingredients. Building upon our previous research, demonstrating the antioxidant potential of hydroalcoholic extracts derived from two distinct cork powders (P0 and P1), in this work, aqueous extracts were prepared and analyzed. The safety and bioactivities of the newly obtained aqueous extracts, as well as the 30% ethanol extracts, previously reported to be the most promising for skin application, were also evaluated. Methods: Aqueous extracts were obtained from cork powders (P0 and P1) and the identification and quantification of some polyphenols was achieved by liquid chromatography (LC). Antioxidant potential was screened by DPPH method and the bioactivity and safety of extracts were further explored using cell-based assays. Results: All extracts exhibited a reduction in age-related markers, including senescence-associated beta-galactosidase (SA-β-gal) activity. Additionally, they demonstrated a pronounced anti-inflammatory effect by suppressing the production of several pro-inflammatory mediators in macrophages upon lipopolysaccharide stimulation. Moreover, the extracts upregulated genes and proteins associated with antioxidant activity, such as heme oxygenase 1. The aqueous extract from P1 powder was especially active in reducing pro-inflammatory mediators, namely the Nos2 gene, inducible nitric oxide protein levels, and nitric oxide production. Moreover, it did not induce skin irritation, as assessed by the EpiSkin test, in compliance with the OECD Test Guidelines. Conclusions: Overall, our findings underscore the potential of aqueous extracts derived from cork waste streams to mitigate various hallmarks of skin aging, including senescence and inflammaging, and their suitability for incorporation into cosmetics formulations. These results warrant further exploration for their application in the pharmaceutical and cosmetic industries and could foster a sustainable and circular bioeconomy.

Delayed cutaneous wound healing in young and old female mice is associated with differential growth factor release but not inflammatory cytokine secretion

The capacity for tissue repair during wound healing declines with age. A chronic low but systemic inflammatory status, often called "inflammaging", is considered a key factor that contributes to impaired tissue regeneration. This phenomenon has been substantiated by an increased number of immune cells in wound-tissue of old mice. Although immune cells coordinate an inflammatory response by their secretome the composition of the wound milieu has not been examined. In young (2 months) and old (18 months) female mice, excision wounds were induced using a punch biopsy device, i.e., the healing progress occurred through secondary intention. The closure rate was analyzed for 7 days. At days 1, 3 and 7 post-surgery, wound specimen were investigated for immunohistochemical detection of granulocytes, M1-macrophages and mesenchymal stem cells of the skin. The concentrations of inflammatory cytokines and regenerative growth factors were determined in tissue homogenates by ELISA. The carbonyl assay was used to determine protein oxidation. In old mice, the wound closure was delayed between days 1 and 3 post-surgery, as was the peak of immune cell infiltration. There was no age effect on the concentration of inflammatory cytokines, but wounds of young animals contained higher number of mesenchymal stem cells and increased levels of growth factors. Protein oxidation was increased with age. The present study suggests that a reduced regenerative capacity rather than an enhanced inflammatory score affected the tissue regeneration process in old mice.

Investigation into the significant role of dermal-epidermal interactions in skin ageing utilising a bioengineered skin construct

Increased prevalence of skin ageing is a growing concern due to an ageing global population and has both sociological and psychological implications. The use of more clinically predictive in vitro methods for dermatological research is becoming commonplace due to initiatives and the cost of clinical testing. In this study, we utilise a well-defined and characterised bioengineered skin construct as a tool to investigate the cellular and molecular dynamics involved in skin ageing from a dermal perspective. Through incorporation of ageing fibroblasts into the dermal compartment we demonstrate the significant impact of dermal-epidermal crosstalk on the overlying epidermal epithelium. We characterise the paracrine nature of dermal-epidermal communication and the impact this has during skin ageing. Soluble factors, such as inflammatory cytokines released as a consequence of senescence associated secretory phenotype (SASP) from ageing fibroblasts, are known to play a pivotal role in skin ageing. Here, we demonstrate their effect on epidermal morphology and thickness, but not keratinocyte differentiation or tissue structure. Through a novel in vitro strategy utilising bioengineered tissue constructs, this study offers a unique reductionist approach to study epidermal and dermal compartments in isolation and tandem.

Natural Modulators of Key Signaling Pathways in Skin Inflammageing

Low-grade chronic inflammation without obvious infection is defined as "inflammageing" and a key driver of skin ageing. Although the importance of modulating inflammageing for treating skin diseases and restoring cutaneous homeostasis is increasingly being recognized. However, the mechanisms underlying skin inflammageing, particularly those associated with natural treatments, have not been systematically elucidated. This review explores the signaling pathways associated with skin inflammageing, as well as the natural plants and compounds that directly or indirectly target these pathways. Nine signaling pathways and 60 plants/constituents related to skin anti-inflammageing are discussed, exploring plant mechanisms to mitigate skin inflammageing. Common natural plants with anti-inflammageing activity are detailed by active ingredients, mechanisms, therapeutic potential, and quantitative effects on skin inflammageing modulation. This review strengthens our understanding of these botanical ingredients as natural interventions against skin inflammageing and provides directions for future research.

CD4+ T Cells Occupy Perivascular and Perifollicular Niches in Healthy Human Skin

Regulatory T cells (Tregs) are specialised T lymphocytes that sit at the nexus of immune regulation and tissue repair. While it is appreciated that a substantial number of Tregs are present in healthy human skin, less is known about their microanatomic spatial localisation. Knowledge about the specialised niches that Tregs occupy may aid in rational drug development to treat dermatologic diseases. Thus, we performed multiplexed immunohistochemistry for CD4 and FOXP3 (the lineage-defining transcription factor of Tregs) on healthy skin sections obtained from eight different cutaneous sites, and quantified Tregs and Tcon in distinct regions. We found that Tregs (CD4+ FOXP3+) comprised roughly 20% of CD4+ T cells in skin and that Tregs and T-conventional cells (Tcon; CD4+ Foxp3-) are enriched in follicularly dense skin and show preferential accumulation in perivascular and perifollicular niches in the upper dermis. Additionally, male skin shows a significant increase in the numbers of Tregs and Tcon, while female skin shows a higher Tcon:Treg ratio. We also find that the frequency of skin Tregs declines over time. Overall, we conclude that the upper dermal perivascular region is a niche that supports the accumulation of CD4+ T cells in steady-state human skin.

Biotics as novel therapeutics in targeting signs of skin ageing via the gut-skin axis

Skin ageing is a phenomenon resulting from the aggregative changes to skin structure and function and is clinically manifested by physical features such as wrinkles, hyperpigmentation, elastosis, telangiectasia, and deterioration of skin barrier integrity. One of the main drivers of skin ageing, UV radiation, negatively influences the homeostasis of cells and tissues comprising the skin by triggering production of immune-mediated reactive oxygen species (ROS) and pro-inflammatory cytokines, as well as a various hormones and neuropeptides. Interestingly, an established link between the gut and the skin coined the 'gut-skin axis' has been demonstrated, with dysbiosis and gut barrier dysfunction frequently observed in certain inflammatory skin conditions and more recently, implicated in skin ageing. Therapeutic use of 'biotics' including prebiotics, probiotics, postbiotics, and synbiotics, which modulate the gut microbiota and production of microbially associated metabolites, influence the activity of the gut mucosal and immune systems and are showing promise as key candidates in addressing signs of skin ageing. In this review we aim to focus on the structure and function of the gut-skin axis and showcase the recent in-vitro and clinical evidence demonstrating the beneficial effects of select biotics in targeting signs of skin ageing and discuss the proposed mechanisms mediated via the gut-skin axis underpinning these effects.

An Advanced Combinatorial System from Vitis vinifera Leaves and Propolis Enhances Antioxidants' Skin Delivery and Fibroblasts Functionality

Background/Objectives: Vine leaves are a bulky by-product that are disposed of and treated as waste in the wine production process. In the present study polyphenols from vine leaves were extracted and simultaneously encapsulated in a new delivery system consisting of liposomes and cyclodextrins. This system was further combined with propolis polyphenols encapsulated in cyclodextrins, resulting in a colloidal suspension for the release of antioxidants in a time-controlled way, the rate of which depends on the ratio of the materials. The result is a raw material that exhibits antioxidant and ECM protective effects when administered in skin fibroblasts (NHDFs). Methods: The antioxidant and ECM promoting efficacy of the produced raw material was assessed by the Folin-Ciocalteu method, DPPH assay, and in cellulo assays in fibroblasts, such as the cell viability assay, scratch assay, cell migration assay, gene expression analysis, and immunofluorescence analysis, for the detection, visualization, and quantification of collagen-I, collagen-IIIa, and elastin signals and collagenase assay. Results: Treatment of NHDFs with the combinatorial delivery system promoted collagen and elastin synthesis and deposition in normal conditions and, upon induced external stress, as assessed by in vitro transcriptomic and proteomic analysis. A significant inhibition of collagenase was also observed, suggesting a multitargeted efficacy of the active ingredients also by preventing collagen degradation. Conclusions: Therefore, this liposome-cyclodextrin encapsulated polyphenol complex represents a novel bioactive ingredient with promising skin applications.

Aging, ROS, and cellular senescence: a trilogy in the progression of liver fibrosis

Ageing is an inevitable and multifaceted biological process that impacts a wide range of cellular and molecular mechanisms, leading to the development of various diseases, such as liver fibrosis. Liver fibrosis progresses to cirrhosis, which is an advanced form due to high amounts of extracellular matrix and restoration of normal liver structure with failure to repair damaged tissue and cells, marking the end of liver function and total liver failure, ultimately death. The most important factors are reactive oxygen species (ROS) and cellular senescence. Oxidative stress is defined as an impairment by ROS, which are by-products of the mitochondrial electron transport chain and other key molecular pathways that induce cell damage and can activate cellular senescence pathways. Cellular senescence is characterized by pro-inflammatory cytokines, growth factors, and proteases secreted by senescent cells, collectively known as the senescence-associated secretory phenotype (SASP). The presence of senescent cells, which disrupt tissue architecture and function and increase senescent cell production in liver tissues, contributes to fibrogenesis. Hepatic stellate cells (HSCs) are activated in response to chronic liver injury, oxidative stress, and senescence signals that drive excessive production and deposition of extracellular matrix. This review article aims to provide a comprehensive overview of the pathogenic role of ROS and cellular senescence in the aging liver and their contribution to fibrosis.

Organoids as Tools for Investigating Skin Aging: Mechanisms, Applications, and Insights

Organoids have emerged as transformative tools in biomedical research, renowned for their ability to replicate the complexity construct of human tissues. Skin aging is a multifaceted biological process, influenced by both intrinsic factors and extrinsic factors. Traditional models for studying skin aging often fall short in capturing the intricate dynamics of human skin. In contrast, skin organoids offer a more physiologically relevant system, reflecting the structural and functional characteristics of native skin. These characteristics make skin organoids highly suitable for studying the mechanisms of skin aging, identifying novel therapeutic targets, and testing anti-aging interventions. Despite their promise, challenges such as limited scalability, reproducibility, and ethical considerations remain. Addressing these hurdles through interdisciplinary research and technological advancements will be essential to maximizing the potential of skin organoids for dermatological research and personalized anti-aging therapies.

Clinical evaluation of combined autologous Platelet-Rich Plasma and Volume-Controlled Ozone Therapy in Facial Rejuvenation: A randomized controlled Pilot Study

Platelet rich plasma and ozone therapy have been suggested in the clinical setting as promising and adjuvant therapies for managing the symptoms related to the facial aging. However, there is a lack of evidence about the effects of combining both therapies on rejuvenation. Thus, the aim of the present study was to evaluate and to compare the safety and efficacy of both therapies in facial aging. A single-center prospective pilot study was conducted. Female participants, aged 40 to 60 years, were randomized into 2 groups: participants received the platelet rich plasma treatment (PRP); participants received the therapy with platelet rich plasma associated with ozone therapy (PRPOT). Interventions were performed using the facial intradermal technique in 42 pre-established points, for 4 sessions with an interval of 15 days between them. After analyses performed using photographic records, assessment of frontal, periorbital, nasolabial and marionette wrinkles (Wrinkle Assessment Scale), self-esteem assessment (Brazilian Version of Rosenberg's Self-Esteem Scale) and assessment of patient satisfaction (FACE-Q) can be suggested that the platelet rich plasma protocol performed in the present study, as well as its association with volume-controlled ozone therapy, proved to be safe and potentially promising modalities in the treatment of facial aging.

Differences in cell subsets between sun-exposed and unexposed skin: preliminary single-cell sequencing and biological analysis from a single case

Introduction

The composition and subsets of skin cells continuously change in a dynamic manner. However, the specific microcosmic alterations of human photoaged skin, independent of chronologic aging, remain unclear and have been infrequently analyzed. This study aimed to evaluate the biological processes and mechanisms underlying cell-subgroup alterations in skin photoaging.

Methods

We utilized single-cell sequencing and biological analysis from a single case to investigate the effects of photoaging. Skin punch biopsies were taken from sun-exposed forearm skin and unexposed buttock skin from the same individual for comparative analysis.

Results

Our analysis identified 25 cell clusters and 12 skin cell types, revealing significant changes in unique gene expressions between the sun-exposed and unexposed skin samples. A comparison of cell numbers within each cluster revealed 9 dominant cell clusters in sun-exposed skin and 16 dominant cell clusters in unexposed skin. Enrichment analysis indicated that PD-L1 expression and the PD-1 checkpoint pathway were more prominent in sun-exposed skin, while MAPK, TNF-alpha, TGF-beta, and apoptosis pathways were more enriched in hair follicle cells of sun-exposed skin.

Discussion

This study reveals changes in cell components in photoaged skin from a single case and provides novel insights into cellular subpopulations and pathology during repeated UVA-induced skin damage. These findings enhance our understanding of the complex interplay between different cells in photoaged skin and offer potential targets for preventing human skin photoaging and UV-induced skin cancers.

Skin senescence-from basic research to clinical practice

The most recognizable implications of tissue aging manifest themselves on the skin. Skin laxity, roughness, pigmentation disorders, age spots, wrinkles, telangiectasia or hair graying are symptoms of physiological aging. Development of the senescent phenotype depends on the interaction between aging cells and remodeling of the skin's extracellular matrix (ECM) that contains collagen and elastic fiber. Aging changes occur due to the combination of both endogenous (gene mutation, cellular metabolism or hormonal agents) and exogenous factors (ultraviolet light, environmental pollutants, and unsuitable diet). However, overproduction of mitochondrial reactive oxygen species (ROS) is a key factor driving cellular senescence. Aging theories have disclosed a range of diverse molecular mechanisms that are associated with cellular senescence of the body. Theories best supported by evidence include protein glycation, oxidative stress, telomere shortening, cell cycle arrest, and a limited number of cell divisions. Accumulation of the ECM damage is suggested to be a key factor in skin aging. Every cell indicates a functional and morphological change that may be used as a biomarker of senescence. Senescence-associated β-galactosidase (SA-β-gal), cell cycle inhibitors (p16INK4a, p21CIP1, p27, p53), DNA segments with chromatin alterations reinforcing senescence (DNA-SCARS), senescence-associated heterochromatin foci (SAHF), shortening of telomeres or downregulation of lamina B1 constitute just an example of aging biomarkers known so far. Aging may also be assessed non-invasively through measuring the skin fluorescence of advanced glycation end-products (AGEs). This review summarizes the recent knowledge on the pathogenesis and clinical conditions of skin aging as well as biomarkers of skin senescence.

The emerging importance of lymphangiogenesis in aging and aging-associated diseases

Lymphatic aging represented by cellular and functional changes, is involved in increased geriatric disorders, but the intersection between aging and lymphatic modulation is less clear. Lymphatic vessels play an essential role in maintaining tissue fluid homeostasis, regulating immune function, and promoting macromolecular transport. Lymphangiogenesis and lymphatic remodeling following cellular senescence and organ deterioration are crosslinked with the progression of some lymphatic-associated diseases, e.g., atherosclerosis, inflammation, lymphoedema, and cancer. Age-related detrimental tissue changes may occur in lymphatic vessels with diverse etiologies, and gradually shift towards chronic low-grade inflammation, so-called inflammaging, and lead to decreased immune response. The investigation of the relationship between advanced age and organ deterioration is becoming an area of rapidly increasing significance in lymphatic biology and medicine. Here we highlight the emerging importance of lymphangiogenesis and lymphatic remodeling in the regulation of aging-related pathological processes, which will help to find new avenues for effective intervention to promote healthy aging.

Evaluation of Sarcopenia by Psoas Muscle Measurements in Bullous Pemphigoid: A Single-Institution Survey in Japan

Bullous pemphigoid (BP) is a rare autoimmune blistering disease that primarily affects elderly individuals. Based on the Bullous Pemphigoid Disease Area Index (BPDAI) severity assessment, immunosuppressive drugs are recommended for severe cases that fall within the more than moderate classes. Sarcopenia, which is characterized by decreased skeletal muscle mass and function in elderly patients, is a progressive and widespread skeletal muscle disease. We retrospectively surveyed patients who received treatment for BP at our hospital between 2012 and 2024 to evaluate the relevance of sarcopenia, as assessed using the psoas muscle mass index (PMI), and to investigate the benefit of relapse-free survival (RFS). A total of 59 patients with BP were included in this study. A total of 57.6% (34 of 59 patients) of the BP patients had sarcopenia, as measured by PMI. Kaplan-Meier analysis showed that the sarcopenia group (n = 34) had a median RFS of 394 days, which was not longer than that of the non-sarcopenia group (n = 25, 275 days) (p = 0.894). No significant difference in RFS was observed in the subgroup analysis based on the severity of BPDAI. Our real-world data confirmed the high prevalence of sarcopenia in the BP population and the efficacy of standard treatment centered on immunosuppressive therapy based on the severity of BPDAI. There is little basis for reducing oral corticosteroids below 0.5 mg/kg based solely on the patient's perceived frailty, regardless of the severity of the BPDAI. Limited evidence is available to assess the association between sarcopenia and autoimmune diseases in terms of their etiology. As populations continue to age globally, it is important for clinicians to prioritize addressing diseases while considering whether patients experience frailty in daily practice.

Systemic comparison of molecular characteristics in different skin fibroblast senescent models

BACKGROUND

Senescent human skin primary fibroblast (FB) models have been established for studying aging-related, proliferative, and inflammatory skin diseases. The aim of this study was to compare the transcriptome characteristics of human primary dermal FBs from children and the elderly with four senescence models.

METHODS

Human skin primary FBs were obtained from healthy children (FB-C) and elderly donors (FB-E). Senescence models were generated by ultraviolet B irradiation (FB-UVB), D-galactose stimulation (FB-D-gal), atazanavir treatment (FB-ATV), and replication exhaustion induction (FB-P30). Flow cytometry, immunofluorescence staining, real-time quantitative polymerase chain reaction, co-culturing with immune cells, and bulk RNA sequencing were used for systematic comparisons of the models.

RESULTS

In comparison with FB-C, FB-E showed elevated expression of senescence-related genes related to the skin barrier and extracellular matrix, proinflammatory factors, chemokines, oxidative stress, and complement factors. In comparison with FB-E, FB-UVB and FB-ATV showed higher levels of senescence and expression of the genes related to the senescence-associated secretory phenotype (SASP), and their shaped immune microenvironment highly facilitated the activation of downstream immune cells, including T cells, macrophages, and natural killer cells. FB-P30 was most similar to FB-E in terms of general transcriptome features, such as FB migration and proliferation, and aging-related characteristics. FB-D-gal showed the lowest expression levels of senescence-related genes. In comparisons with the single-cell RNA sequencing results, FB-E showed almost complete simulation of the transcriptional spectrum of FBs in elderly patients with atopic dermatitis, followed by FB-P30 and FB-UVB. FB-E and FB-P30 showed higher similarity with the FBs in keloids.

CONCLUSIONS

Each senescent FB model exhibited different characteristics. In addition to showing upregulated expression of natural senescence features, FB-UVB and FB-ATV showed high expression levels of senescence-related genes, including those involved in the SASP, and FB-P30 showed the greatest similarity with FB-E. However, D-galactose-stimulated FBs did not clearly present aging characteristics.

Cutaneous adaptive immunity and uraemia: a narrative review

Chronic kidney disease affects 1 in 10 people globally, with a prevalence twenty times that of cancer. A subset of individuals will progress to end-stage renal disease (ESRD) where renal replacement therapy is required to maintain health. Cutaneous disease, including xerosis and pruritus, are endemic amongst patients with ESRD. In the uraemia-associated immune deficiency of ESRD, impaired circulating immune responses contribute to increased infection risk and poorer vaccination response. Clinical manifestations of dysregulated adaptive immunity within the skin have been well-described and have been posited to play a role in cutaneous features of ESRD. However, our understanding of the mechanisms by which adaptive immunity within the skin is affected by uraemia is relatively limited. We provide an overview of how the cutaneous adaptive immune system is impacted both directly and indirectly by uraemia, highlighting that much work has been extrapolated from the circulating immune system and often has not been directly evaluated in the skin compartment. We identify knowledge gaps which may be addressed by future research. Ultimately, greater understanding of these pathways may facilitate novel therapeutic approaches to ameliorate widespread cutaneous symptomatology in ESRD.

Integrated analysis of facial microbiome and skin physio-optical properties unveils cutotype-dependent aging effects

BACKGROUND

Our facial skin hosts millions of microorganisms, primarily bacteria, crucial for skin health by maintaining the physical barrier, modulating immune response, and metabolizing bioactive materials. Aging significantly influences the composition and function of the facial microbiome, impacting skin immunity, hydration, and inflammation, highlighting potential avenues for interventions targeting aging-related facial microbes amidst changes in skin physiological properties.

RESULTS

We conducted a multi-center and deep sequencing survey to investigate the intricate interplay of aging, skin physio-optical conditions, and facial microbiome. Leveraging a newly-generated dataset of 2737 species-level metagenome-assembled genomes (MAGs), our integrative analysis highlighted aging as the primary driver, influencing both facial microbiome composition and key skin characteristics, including moisture, sebum production, gloss, pH, elasticity, and sensitivity. Further mediation analysis revealed that skin characteristics significantly impacted the microbiome, mostly as a mediator of aging. Utilizing this dataset, we uncovered two consistent cutotypes across sampling cities and identified aging-related microbial MAGs. Additionally, a Facial Aging Index (FAI) was formulated based on the microbiome, uncovering the cutotype-dependent effects of unhealthy lifestyles on skin aging. Finally, we distinguished aging related microbial pathways influenced by lifestyles with cutotype-dependent effect.

CONCLUSIONS

Together, our findings emphasize aging's central role in facial microbiome dynamics, and support personalized skin microbiome interventions by targeting lifestyle, skin properties, and aging-related microbial factors. Video Abstract.

Pomegranate (Punica granatum L.) Extract Effects on Inflammaging

Pomegranate is a notable source of nutrients, containing a considerable proportion of organic acids, polysaccharides, vitamins, fatty acids, and polyphenols such as flavonoids, phenolic acids, and tannins. It is also rich in nutritionally important minerals and chemical elements such as K, P, Na, Ca, Mg, and N. The presence of several bioactive compounds and metabolites in pomegranate has led to its incorporation into the functional food category, where it is used for its numerous therapeutic properties. Pomegranate's bioactive compounds have shown antioxidant, anti-inflammatory, and anticancer effects. Aging is a process characterized by the chronic accumulation of damages, progressively compromising cells, tissues, and organs over time. Inflammaging is a chronic, subclinical, low-grade inflammation that occurs during the aging process and is linked to many age-related diseases. This review aims to summarize and discuss the evidence of the benefits of pomegranate extract and its compounds to slow the aging processes by intervening in the mechanisms underlying inflammaging. These studies mainly concern neurodegenerative and skin diseases, while studies in other fields of application need to be more practical. Furthermore, no human studies have demonstrated the anti-inflammaging effects of pomegranate. In the future, supplementation with pomegranate extracts, polyphenols, or urolithins could represent a valuable low-risk complementary therapy for patients with difficult-to-manage diseases, as well as a valid therapeutic alternative for the topical or systemic treatment of skin pathologies.

Evaluation of the photothermal effects of the subdermal high-power laser in the skin of an experimental rat model

The aim of the present study was to evaluate the photothermal effects of a subdermal high-power diode laser at a wavelength (λ) of 1470 nm in the skin of rats. Twenty male Wistar rats were used, divided into 2 groups: placebo laser (PL) and active laser (AL). A high-power diode laser equipment was applied to 5 subdermal vectors on the animal's back region. The results demonstrated that active laser animals showed a better arrangement of collagen fiber bands, an increase in the thickness of the dermis and the number of vessels. Furthermore, animals treated with active laser showed an increased immunoexpression of TGF-β and VEGF compared to the placebo. The present work demonstrated that the subdermal high-power diode laser increases the vascularization and the expression of factors that enhance skin regeneration and may be promising resource in the esthetic and dermatology clinical treatment of skin rejuvenation.

Chemical profiling of Anthriscus cerefolium (L.) Hoffm., biological potential of the herbal extract, molecular modeling and KEGG pathway analysis

This study was designed to investigate chemical composition and biological activities of the Anthriscus cerefolium methanolic extract. Chemical characterization of the extracts was performed by LC-HRMS/MS analysis. Antimicrobial activities of the extract were investigated on six bacteria and eight fungi while antioxidant activity was assessed by six different assays. Anti-enzymatic activity of the methanolic extract was tested on five enzymes associated with therapy of neurodegenerative diseases and diabetes mellitus type 2. Cytotoxic properties of the extract were tested on human immortalized keratinocytes (HaCaT) and tumor cell lines (SiHa, MCF7, HepG2). Anti-inflammatory activity of the extract was assessed on bacteria mediated inflammation model using HaCaT cell line. Molecular docking studies of enzymes and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis were performed. The results showed that the obtained extract was rich in phenolic compounds (a total of seventy-two were identified), with malonyl-1,4-O-dicaffeoylquinic acid and 3,5-O-dicaffeoylquinic acid dominating in the sample. The extract expressed antimicrobial, antioxidant, anti-enzymatic, cytotoxic and anti-inflammatory properties. The identified compounds demonstrated strong binding to the acetylcholinesterase (AChE) and to a lesser extent, to the butyrylcholinesterase (BChE), glucosidase, amylase, and modestly, to tyrosinase. KEGG pathway analysis has shown that the certain phenolic compounds may be related to anti-tumor, anti-inflammatory and anti-microbial activities of the extract. The data obtained suggest that phenolic compounds of the extract and their mixtures should be considered for future research as ingredients in pharmaceutical and nutraceutical formulations.

Promising Support Coming from Nature: Antioxidant and Anti-Inflammatory Potential of Castanea sativa Wood Distillate on Skin Cells

Tissue homeostasis, function recovery, and protection mechanisms are boosted by the balanced and timely control of inflammation and oxidative stress. Nowadays, many natural products and bio-derivates exhibit antioxidant and anti-inflammatory activity, supporting medical care and tissue wellness against inflammation, oxidative stress, and inflammaging. Castanea sativa wood distillate (WD) is a bio-derivative used as a corroborant and biofertilizer in agriculture. Based on the safety profile of low concentrations of WD on human cells, the present study aims to assess the anti-inflammatory and antioxidant activity of WD on different cell types in the integumentary system. Human keratinocytes, mucosal epithelium, dermal fibroblasts, and endothelial cells were exposed to WD, and the concentrations devoid of pro-apoptotic potential were profiled. Then, the effect of nontoxic doses of WD revealed an anti-inflammatory effect, observed through the immunodetection of prostanoid cascade markers in experimentally induced inflammation. A reduction in endothelial hyperpermeability was evidenced by the immunofluorescence analysis of cell-cell adhesion proteins, VE-cadherin and ZO-1. In addition, WD buffered the exogenously produced oxidative stress. On the whole, WD showed both anti-inflammatory and antioxidant activities on the various cell types, preserving endothelial barrier integrity. Overall, this study supports the involvement of this bio-derivative in novel exploitable fields, such as therapeutic dermatological applications for human and animal medical care.

GelMA loaded with platelet lysate promotes skin regeneration and angiogenesis in pressure ulcers by activating STAT3

Pressure ulcers (PU) are caused by persistent long-term pressure, which compromises the integrity of the epidermis, dermis, and subcutaneous adipose tissue layer by layer, making it difficult to heal. Platelet products such as platelet lysate (PL) can promote tissue regeneration by secreting numerous growth factors based on clinical studies on skin wound healing. However, the components of PL are difficult to retain in wounds. Gelatin methacrylate (GelMA) is a photopolymerizable hydrogel that has lately emerged as a promising material for tissue engineering and regenerative medicine. The PL liquid was extracted, flow cytometrically detected for CD41a markers, and evenly dispersed in the GelMA hydrogel to produce a surplus growth factor hydrogel system (PL@GM). The microstructure of the hydrogel system was observed under a scanning electron microscope, and its sustained release efficiency and biological safety were tested in vitro. Cell viability and migration of human dermal fibroblasts, and tube formation assays of human umbilical vein endothelial cells were applied to evaluate the ability of PL to promote wound healing and regeneration in vitro. Real-time polymerase chain reaction (PCR) and western blot analyses were performed to elucidate the skin regeneration mechanism of PL. We verified PL's therapeutic effectiveness and histological analysis on the PU model. PL promoted cell viability, migration, wound healing and angiogenesis in vitro. Real-time PCR and western blot indicated PL suppressed inflammation and promoted collagen I synthesis by activating STAT3. PL@GM hydrogel system demonstrated optimal biocompatibility and favorable effects on essential cells for wound healing. PL@GM also significantly stimulated PU healing, skin regeneration, and the formation of subcutaneous collagen and blood vessels. PL@GM could accelerate PU healing by promoting fibroblasts to migrate and secrete collagen and endothelial cells to vascularize. PL@GM promises to be an effective and convenient treatment modality for PU, like chronic wound treatment.

Emerging Role of Fibroblasts in Vitiligo: A Formerly Underestimated Rising Star

Vitiligo is a disfiguring depigmentation disorder characterized by loss of melanocytes. Although numerous studies have been conducted on the pathogenesis of vitiligo, the underlying mechanisms remain unclear. Although most studies have focused on melanocytes and keratinocytes, growing evidence suggests the involvement of dermal fibroblasts, residing deeper in the skin. This review aims to elucidate the role of fibroblasts in both the physiological regulation of skin pigmentation and their pathological contribution to depigmentation, with the goal of shedding light on the involvement of fibroblasts in vitiligo. The topics covered in this review include alterations in the secretome, premature senescence, autophagy dysfunction, abnormal extracellular matrix, autoimmunity, and metabolic changes.

Skin Aging and the Upcoming Role of Ferroptosis in Geroscience

The skin is considered the most important organ system in mammals, and as the population ages, it is important to consider skin aging and anti-aging therapeutic strategies. Exposure of the skin to various insults induces significant changes throughout our lives, differentiating the skin of a young adult from that of an older adult. These changes are caused by a combination of intrinsic and extrinsic aging. We report the interactions between skin aging and its metabolism, showing that the network is due to several factors. For example, iron is an important nutrient for humans, but its level increases with aging, inducing deleterious effects on cellular functions. Recently, it was discovered that ferroptosis, or iron-dependent cell death, is linked to aging and skin diseases. The pursuit of new molecular targets for ferroptosis has recently attracted attention. Prevention of ferroptosis is an effective therapeutic strategy for the treatment of diseases, especially in old age. However, the pathological and biological mechanisms underlying ferroptosis are still not fully understood, especially in skin diseases such as melanoma and autoimmune diseases. Only a few basic studies on regulated cell death exist, and the challenge is to turn the studies into clinical applications.

Para-Hydroxycinnamic Acid Mitigates Senescence and Inflammaging in Human Skin Models

Para-hydroxycinnamic acid (pHCA) is one of the most abundant naturally occurring hydroxycinnamic acids, a class of chemistries known for their antioxidant properties. In this study, we evaluated the impact of pHCA on different parameters of skin aging in in vitro skin models after H2O2 and UV exposure. These parameters include keratinocyte senescence and differentiation, inflammation, and energy metabolism, as well as the underlying molecular mechanisms. Here we demonstrate that pHCA prevents oxidative stress-induced premature senescence of human primary keratinocytes in both 2D and 3D skin models, while improving clonogenicity in 2D. As aging is linked to inflammation, referred to as inflammaging, we analyzed the release of IL-6, IL-8, and PGE2, known to be associated with senescence. All of them were downregulated by pHCA in both normal and oxidative stress conditions. Mechanistically, DNA damage induced by oxidative stress is prevented by pHCA, while pHCA also exerts a positive effect on the mitochondrial and glycolytic functions under stress. Altogether, these results highlight the protective effects of pHCA against inflammaging, and importantly, help to elucidate its potential mechanisms of action.

Tumor Necrosis Factor-Alpha: Ally and Enemy in Protean Cutaneous Sceneries

Skin is the forestage for a series of many-sided functions of tumor necrosis factor-alpha (TNF-α), a proinflammatory cytokine with staggering versatility and sizable implications for tissue homeostasis, immune responses, angiogenesis, apoptosis, local and systemic inflammation. An aberrant TNF-α-mediated crosstalk has been linked to the pathogenesis of acute and chronic skin inflammatory diseases, and indeed, TNF-α dysregulation can contribute to the development and progression of psoriasis, vitiligo, local damage following exposition to ultraviolet light radiations, cutaneous lupus erythematosus, and acne vulgaris. Therapies that target TNF-α are conspicuously used in the treatment of different skin disorders, aiming to modulate the in vivo immune functions triggered by many cutaneous cells, including keratinocytes, mast cells, or Langerhans cells, and reduce inflammation taking place within the skin. Herein, we focus on the key relationships between TNF-α and distinct skin non-neoplastic inflammatory or physiologic conditions, showing that a natural induction of TNF-α may have a protective significance but that TNF-α overproduction may be harmful or even lethal. Many questions remain unraveled in the therapeutic practice, and caution should be exercised due to eventual backlashes exerted by TNF-α in maintaining skin health or in provoking skin disease.

Adverse outcome pathway-based approach to reveal the mechanisms of skin sensitization and long-term aging effects of chlorothalonil

Chlorothalonil (CHT) is a widely used antifungal agent and is reported to be a sensitizer that can cause allergic contact dermatitis (ACD). ACD initiation is associated with various innate immune cell contributions and is usually accompanied by persistent inflammation, which is a potential contributing factor to skin damage. However, detailed information on the mechanisms by which CHT induces skin sensitization and damage is still insufficient. This study focused on investigating the possible sensitization process and mechanism of CHT and the adverse effects of repeated CHT exposure. CHT activates dendritic cells and promotes the proliferation of lymph cells in the skin sensitization phase, causing severe inflammation. Keratinocytes activate the NLRP3 inflammasome pathway to cause inflammation during CHT treatment, and macrophages also secrete inflammatory cytokines. In addition, CHT-induced inflammation triggered skin wrinkles, decreased epidermal thickness and decreased collagen. Cell experiments also showed that repeated exposure to CHT led to cell proliferation inhibition and senescence, and CHT-induced autophagy dysfunction was not only the reason for inflammation but also for senescence. This study defined the possible process through which CHT is involved in the skin sensitization phase and elucidated the mechanism of CHT-induced inflammation in innate immune responses. We also determined that repeated CHT exposure caused persistent inflammation, ultimately leading to skin aging.

Exploring the anti-skin inflammation substances and mechanism of Paeonia lactiflora Pall. Flower via network pharmacology-HPLC integration

BACKGROUND

Paeonia lactiflora Pall. (PL) is widely used in China as a homologous plant of medicine and food. PL flower is rich in bioactive substances with anti-inflammatory effects, while the pathogenesis of skin inflammation is complex and the specific mechanism is not clear, the current treatment of skin inflammation is mainly hormonal drugs, and hormonal drugs have obvious toxic side effects. The research on the treatment of skin inflammation by PL flowers is relatively small, so this study provides a basis for the development and utilisation of PL resources.

OBJECTIVE

Our study was to investigate the interventional effects of PL flower extracts on skin inflammation and thus to understand its functional role in the treatment of skin inflammation and its molecular mechanisms.

METHODS

The major active substances in PL flower extracts were investigated by the HPLC-DAD method, and the potential targets of action were predicted by network pharmacology, which was combined with in vitro experimental validation to explore the mechanism of PL flower extracts on the regulation of skin inflammation. The HPLC-DAD analysis identified seven major active components in PL flower extracts, and in response to the results, combined with the potential mechanism of network pharmacological prediction with skin inflammation, the PL flower extract is closely related to MAPK and NF-κB signaling pathways. In addition, we also investigated the interventional effects of PL flower extract on skin inflammation by western blot detection of MAPK signaling pathway and NF-κB signaling pathway proteins in cells.

RESULT

Seven active components were identified and quantified from the extract of PL flowers, including Gallic acid, 1,2,3,4,6-O-Pentagalloylglucose, Oxypaeoniflorin, Paeoniflorin, Albiflorin, Benzoyloxypeoniflorin, and Rutin. It was predicted targets for the treatment of skin inflammation, with PPI showing associations with targets such as TNF, MAPK1, and IL-2. KEGG enrichment analysis revealed that the main signaling pathways involved included MAPK and T cell receptor signaling pathways. Cell experiments showed that the peony flower extract could inhibit the release of NO and inflammatory factors, as well as reduce ROS levels and inhibit cell apoptosis. Furthermore, the extract was found to inhibit the activation of the MAPK and NF-κB signaling pathways in cells.

CONCLUSIONS

In this study, we found that PL flower extract can inhibit the production of cell inflammatory substances, suppress the release of inflammatory factors, and deactivate inflammatory signaling pathways, further inhibiting the production of cell inflammation. This indicates that PL flower extract has a therapeutic effect on skin inflammation.

Aging and homeostasis of the hypodermis in the age-related deterioration of skin function

Adipose tissues in the hypodermis, the crucial stem cell reservoir in the skin and the endocrine organ for the maintenance of skin homeostasis undergo significant changes during skin aging. Dermal white adipose tissue (dWAT) has recently been recognized as an important organ for both non-metabolic and metabolic health in skin regeneration and rejuvenation. Defective differentiation, adipogenesis, improper adipocytokine production, and immunological dissonance dysfunction in dWAT lead to age-associated clinical changes. Here, we review age-related alterations in dWAT across levels, emphasizing the mechanisms underlying the regulation of aging. We also discuss the pathogenic changes involved in age-related fat dysfunction and the unfavorable consequences of accelerated skin aging, such as chronic inflammaging, immunosenescence, delayed wound healing, and fibrosis. Research has shown that adipose aging is an early initiation event and a potential target for extending longevity. We believe that adipose tissues play an essential role in aging and form a potential therapeutic target for the treatment of age-related skin diseases. Further research is needed to improve our understanding of this phenomenon.

Emerging Perspectives of YAP/TAZ in Human Skin Epidermal and Dermal Aging

Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are key downstream effectors of the Hippo signaling pathway, which plays a central role in tissue homeostasis, organ development, and regeneration. While the dysregulation of YAP/TAZ has been linked to various human diseases, their involvement in the aging of human skin has only recently begun to manifest. In the skin, the YAP/TAZ effectors emerge as central regulators in maintaining homeostasis of epidermal stem cells and dermal extracellular matrix, and thus intimately linked to skin aging processes. This review underscores recent molecular breakthroughs highlighting how age-related decline of YAP/TAZ activity impacts human epidermal and dermal aging. Gaining insight into the evolving roles of YAP/TAZ in human skin aging presents a promising avenue for the development of innovative therapeutic approaches aimed at enhancing skin health and addressing age-related skin conditions.

A highly biocompatible CE-crosslinked collagen implant with exceptional anti-calcification and collagen regeneration capabilities for aging skin rejuvenation

Skin aging, a complex and inevitable biological process, results in wrinkles, dermal laxity, and skin cancer, profoundly influencing appearance and overall health. Collagen serves as the fundamental element of the dermal matrix; nevertheless, collagen is susceptible to enzymatic degradation within the body. Crosslinking is employed to enhance the physicochemical properties of collagen. However, conventional crosslinking agents may harbor potential issues such as cytotoxicity and calcification risks, constraining their application in the biomedical field. Therefore, we have for the first time developed a highly biocompatible CE-crosslinked collagen implant with exceptional anti-calcification and collagen regeneration capabilities for aging skin rejuvenation. A novel collagen crosslinking agent (CE) was synthesized through a reaction involving chitosan quaternary ammonium salt with 1,4-butanediol diglycidyl ether. Compared to collagen crosslinked with glutaraldehyde (GA), the CE-crosslinked collagen implant exhibited notable stability and durability. The implant demonstrated excellent injectability and viscosity, resisting displacement after implantation. Additionally, the CE-crosslinked collagen implant displayed superior biocompatibility, effectively promoting the proliferation and adhesion of HFF-1 cells compared with the GA-crosslinked collagen. The CE-crosslinked collagen represented a safer and more biologically active implant material. In vivo experiments further substantiated that the implant significantly facilitated collagen regeneration without inducing calcification. The innovative collagen implant has made substantial strides in enhancing aesthetics and reducing wrinkles, presenting the potential for revolutionary progress in the fields of skin rejuvenation and collagen regeneration.

Highly Active Frozen Nanovesicles Microneedles for Senile Wound Healing via Antibacteria, Immunotherapy, and Skin Regeneration

Senile wound healing risks a variety of health complications and makes both economic and psychological burdens on patients greatly. Poor activity of aged dermal fibroblasts (A-FBs) and local disordered immunoreaction in the deep dermis contribute to delayed wound healing. Therefore, the locally complex microenvironment in deep requires additional processing. Herein, a novel double-layer hyaluronic acid methacrylate (HAMA)/polyvinyl alcohol (PVA) microneedle patch (MNP) coated by young fibroblast-derived exosomes (Y-EXOs) (Y-EXOs@HAMA/PVA MNP) is presented for deep drug delivery, aged wound healing and immunoregulation. A spraying and freeze-drying method is applied for keeping the bioactivity of the nanovesicles. An ideal loading of Y-EXOs and enhanced strength for penetration have realized after circulation for times. The Y-EXOs@HAMA/PVA MNP shows an excellent influence on delayed wound healing of aged skin with active A-FBs, more deposition of collagen and less production of IL-17A compared with application of aged fibroblast-derived exosomes (A-EXOs). Moreover, the content microRNAs in Y-EXOs and A-EXOs are sequenced for further study. This study initiatively demonstrates that Y-EXOs have effective function on both anti-aging and anti-inflammation and Y-EXOs@HAMA/PVA MNP is expected as a novel strategy for deep drug delivery for promoting hard wound healing in aged skin in future clinical application.

Comparison of Cryotherapy Performed With Ice or Gel and Superficial Skin Cooling of Older Women: A Randomized, Crossover, Clinical Trial

BACKGROUND AND PURPOSE

Cryotherapy is an affordable and popular treatment of soft tissue injuries, which can reduce inflammation and pain. Studies have specifically addressed young adults and athletes, and these findings have been extended to older adults in clinical practice. Aging is associated with changes in the skin, including collagen degradation, decreased fat layer thickness, and reduced blood flow, which can alter the skin response to stress. Because of age-related changes, there are concerns about the direct use of ice on the skin of older individuals. Skin injuries were also observed after cryotherapy. This study aimed to assess the most effective and safe cryotherapy for superficial skin cooling among older women.

METHODS

Eighteen older women were enrolled in this blinded, randomized, crossover, clinical trial. The mean values (SD) of their age, height, and weight were 70.0 years (6.0), 156.0 cm (9.1), and 72.8 kg (19.5), respectively. The participants underwent cryotherapy using bagged ice, bagged ice plus a wet towel, or gel pack for 20 minutes. The surface temperature of the skin was measured at the end of a 20-minute cryotherapy session using an infrared thermometer. Repeated-measures analysis of variance was conducted to analyze the effect of cryotherapy modalities and time, as well as the interaction between these 2 factors. The secondary outcome was the presence of cryotherapy-induced lesions.

RESULTS AND DISCUSSION

Cryotherapy modalities had significant effects on superficial skin temperature (P = .001). Time points after application also had an effect (P = .0001), and no interaction was observed between cryotherapy modalities and time points (P = .051). Bonferroni post hoc evaluation showed that bagged ice (P = .008) and gel (P = .007) were more effective in decreasing the superficial skin temperature than bagged ice plus wet towel. No difference was observed between bagged ice and gel (P = .32). Three of the 18 patients experienced adverse effects with the gel pack.

CONCLUSION

This study of older women found that ice and gel cooled the skin more effectively than ice wrapped in towels. However, the gel pack had some adverse effects. Therefore, bagged ice is recommended for cryotherapy in older women.

Inflammatory Skin Diseases: Focus on the Role of Suppressors of Cytokine Signaling (SOCS) Proteins

Inflammatory skin diseases include a series of disorders characterized by a strong activation of the innate and adaptive immune system in which proinflammatory cytokines play a fundamental role in supporting inflammation. Skin inflammation is a complex process influenced by various factors, including genetic and environmental factors, characterized by the dysfunction of both immune and non-immune cells. Psoriasis (PS) and atopic dermatitis (AD) are the most common chronic inflammatory conditions of the skin whose pathogeneses are very complex and multifactorial. Both diseases are characterized by an immunological dysfunction involving a predominance of Th1 and Th17 cells in PS and of Th2 cells in AD. Suppressor of cytokine signaling (SOCS) proteins are intracellular proteins that control inflammatory responses by regulating various signaling pathways activated by proinflammatory cytokines. SOCS signaling is involved in the regulation and progression of inflammatory responses in skin-resident and non-resident immune cells, and recent data suggest that these negative modulators are dysregulated in inflammatory skin diseases such as PS and AD. This review focuses on the current understanding about the role of SOCS proteins in modulating the activity of inflammatory mediators implicated in the pathogenesis of inflammatory skin diseases such as PS and AD.

The Influence of Blue Light Exposure on Reconstructed 3-Dimensional Skin Model: Molecular Changes and Gene Expression Profile

Recent studies have provided information about digital eye strain and the potential damage that blue light from digital devices can cause to the eyes. In this study, we analyzed the influence of blue light exposure on reconstructed 3-dimensional skin model using RNA sequencing to identify the expression of transcripts and abnormal events. Three-dimensional skin was exposed to visible light spectrum and isolated blue wavelength for 1, 2, and 4 hours to represent acute exposure and 1 hour over 4 sequential days to represent repeated exposure, respectively, in this in vitro model. We compared gene expression levels with those of unexposed control. Samples submitted to repeated exposure showed reduced AK2 and DDX47, whereas they showed increased PABPC3 gene expression, revealing a significantly negative impact. RT-PCR validation assay with exposed 3-dimensional skin compared with unexposed control regarding 1 and 4 days of incubation showed increased IL-6 signaling mechanism activation and signal transducer and activator of transcription 3 gene STAT3 gene expression, whereas it showed decreased peroxisome proliferator-activated receptor signaling mechanism activation, suggesting an influence on inflammatory pathways. We also demonstrate upregulated gene expression of KIT, MAPK2, and PI3KC in samples from exposed condition, corroborating previous findings related to pigmentation signaling stimuli. These results reveal, to our knowledge, previously unreported data that enable studies on molecular response correlation of in vitro digital blue light exposure and human skin studies.