Making an epidermis

A fungal-binding agglutinin in the skin slime of Japanese flounder (Paralichthys olivaceus) is glyceraldehyde 3-phosphate dehydrogenase

Agglutination of pathogenic microorganisms on the body surface is a significant phenomenon for the prevention of infection. In the present study, we show that an extract of the skin mucus from Japanese flounder (Paralichthys olivaceus) has agglutination activity against the yeast Saccharomyces cerevisiae. We purified this yeast-binding protein, which consists of an approximately 35-kDa homodimer, using affinity chromatography with yeast as a ligand. Multiple internal amino acid sequences of the protein, as determined using liquid chromatography with quadrupole time-of-flight tandem mass spectrometry, mapped to flounder glyceraldehyde 3-phosphate dehydrogenase (GAPDH). An anti-GAPDH antibody inhibited the yeast agglutination activity in the skin mucus extract and stained agglutinated yeast, indicating that flounder GAPDH could agglutinate yeast. The current study suggests that GAPDH, a well-known protein as the sixth enzyme in the glycolytic pathway, is a significant player in mucosal immunity in teleosts.

Assessing Barrier Function in Psoriasis and Cornification Models of Artificial Skin Using Non-Invasive Impedance Spectroscopy

Reconstructed epidermal equivalents (REEs) consist of two distinct cell layers - the stratum corneum (SC) and the keratinocyte layer (KL). The interplay of these layers is particularly crucial in pruritic inflammatory disorders, like psoriasis, where a defective SC barrier is associated with immune dysregulation. However, independent evaluation of the skin barrier function of the SC and KL in REEs is highly challenging because of the lack of quantitative methodologies that do not disrupt the counter layer. Here, a non-invasive impedance spectroscopy technique is introduced for dissecting the distinct contributions of the SC and KL to overall skin barrier function without disrupting the structure. These findings, inferred from the impedance spectra, highlight the individual barrier resistances and maturation levels of each layer. Using an equivalent circuit model, a correlation between impedance parameters and specific skin layers, offering insights beyond traditional impedance methods that address full-thickness skin only is established. This approach successfully detects subtle changes, such as increased paracellular permeability due to mild irritants and the characterization of an immature SC in psoriatic models. This research has significant implications, paving the way for detailed mechanistic investigations and fostering the development of therapies for skin irritation and inflammatory disorders.

Histological comparison of shark dermis across various ecomorphologies

The integument plays essential roles in the structural support, protection, and hydrodynamic capability among fishes. Most research on shark skin has focused on the external epidermal layer, while the larger dermis anchoring the dermal denticles has been mostly ignored. Shark dermis is composed of two layers, the upper stratum laxum and the lower stratum compactum, holding supportive collagen and elastic fibers. There may be morphological and compositional differences in the dermis across various species of sharks that could relate to their different swimming modes and ecologies. The goal of this study was to characterize and describe the dermis among three shark species, Ginglymostoma cirratum, Sphyrna mokarran, and Isurus oxyrinchus, each representing a different swimming mode. Histological characterizations were performed at 16 locations along the body of each shark; variables such as dermal thickness, abundance of collagen and elastic fibers, and fiber size were quantified. Results showed G. cirratum has the thickest skin overall, and the largest fiber size for both collagen and elastic fibers, with overall patterns of increased amounts of collagen fibers and decreased amount of elastic fibers. At the opposite end of the spectrum, I. oxyrinchus showed the thinnest dermis along the flank region, with overall patterns of increased elastic fibers and decreased collagen fibers. These findings may challenge our original assumptions of a rigid body in fast moving sharks and a more flexible body in slower moving sharks and highlight the diversity of the shark integument.

Ontogeny of Skin Stem Cells and Molecular Underpinnings

Skin stem cells (SCs) play a pivotal role in supporting tissue homeostasis. Several types of SCs are responsible for maintaining and regenerating skin tissue. These include bulge SCs and others residing in the interfollicular epidermis, infundibulum, isthmus, sebaceous glands, and sweat glands. The emergence of skin SCs commences during embryogenesis, where multipotent SCs arise from various precursor populations. These early events set the foundation for the diverse pool of SCs that will reside in the adult skin, ready to respond to tissue repair and regeneration demands. A network of molecular cues regulates skin SC behavior, balancing quiescence, self-renewal, and differentiation. The disruption of this delicate equilibrium can lead to SC exhaustion, impaired wound healing, and pathological conditions such as skin cancer. The present review explores the intricate mechanisms governing the development, activation, and differentiation of skin SCs, shedding light on the molecular signaling pathways that drive their fate decisions and skin homeostasis. Unraveling the complexities of these molecular drivers not only enhances our fundamental knowledge of skin biology but also holds promise for developing novel strategies to modulate skin SC fate for regenerative medicine applications, ultimately benefiting patients with skin disorders and injuries.

Sensory neurons increase keratinocyte proliferation through CGRP release in a tissue engineered in vitro model of innervation in psoriasis

Skin denervation has been shown to cause remission of psoriatic lesions in patients, which can reappear if reinnervation occurs. This effect can be induced by the activation of dendritic cells through sensory innervation. However, a direct effect of nerves on the proliferation of keratinocytes involved in the formation of psoriatic plaques has not been investigated. We developed, by tissue engineering, a model of psoriatic skin made of patient skin cells that showed increased keratinocyte proliferation and epidermal thickness compared to healthy controls. When this model was treated with CGRP, a neuropeptide released by sensory neurons, an increased keratinocyte proliferation was observed in the psoriatic skin model, but not in the control. When a sensory nerve network was incorporated in the psoriatic model and treated with capsaicin to induce neuropeptide release, an increase of keratinocyte proliferation was confirmed, which was blocked by a CGRP antagonist while no difference was noticed in the innervated healthy control. We showed that sensory neurons can participate directly to keratinocyte hyperproliferation in the formation of psoriatic lesions through the release of CGRP, independently of the immune system. Our unique tissue-engineered innervated psoriatic skin model could be a valuable tool to better understand the mechanism by which nerves may modulate psoriatic lesion formation in humans. STATEMENT OF SIGNIFICANCE: This study shows that keratinocytes extracted from patients' psoriatic skin retain, at least in part, the disease phenotype. Indeed, when combined in a 3D model of tissue-engineered psoriatic skin, keratinocytes exhibited a higher proliferation rate, and produced a thicker epidermis than a healthy skin control. In addition, their hyperproliferation was aggravated by a treatment with CGRP, a neuropeptide released by sensory nerves. In a innervated model of tissue-engineered psoriatic skin, an increase in keratinocyte hyperproliferation was also observed after inducing neurons to release neuropeptides. This effect was prevented by concomitant treatment with an antagonist to CGRP. Thus, this study shows that sensory nerves can directly participate to affect keratinocyte hyperproliferation in psoriasis through CGRP release.

A Review of Atomic-Force Microscopy in Skin Barrier Function Assessment

Skin barrier function (SBF) disorders are a class of pathologies that affect a significant portion of the world population. These disorders cause skin lesions with intense itch, impacting patients' physical and psychological well-being as well as their social functioning. It is in the interest of patients that their disorder be monitored closely while under treatment to evaluate the effectiveness of the ongoing therapy and any potential adverse reactions. Symptom-based assessment techniques are widely used by clinicians; however, they carry some limitations. Techniques to assess skin barrier impairment are critical for understanding the nature of the disease and for helping personalize treatment. This review recalls the anatomy of the skin barrier and describes an atomic-force microscopy approach to quantitatively monitor its disorders and their response to treatment. We review a panel of studies that show that this technique is highly relevant for SBF disorder research, and we aim to motivate its adoption into clinical settings.

In Silico Elucidation of Key Drivers of Staphyloccocus aureus-Staphyloccocus epidermidis-Induced Skin Damage in Atopic Dermatitis Lesions

Staphylococcus aureus (SA) colonizes and can damage skin in atopic dermatitis lesions, despite being commonly found with Staphylococcus epidermidis (SE), a commensal that can inhibit SA's virulence and kill SA. In this study, we developed an in silico model, termed a virtual skin site, describing the dynamic interplay between SA, SE, and the skin barrier in atopic dermatitis lesions to investigate the mechanisms driving skin damage by SA and SE. We generated 106 virtual skin sites by varying model parameters to represent different skin physiologies and bacterial properties. In silico analysis revealed that virtual skin sites with no skin damage in the model were characterized by parameters representing stronger SA and SE growth attenuation than those with skin damage. This inspired an in silico treatment strategy combining SA-killing with an enhanced SA-SE growth attenuation, which was found through simulations to recover many more damaged virtual skin sites to a non-damaged state, compared with SA-killing alone. This study demonstrates that in silico modelling can help elucidate the key factors driving skin damage caused by SA-SE colonization in atopic dermatitis lesions and help propose strategies to control it, which we envision will contribute to the design of promising treatments for clinical studies.

Soft and Hard Tissue Integration around Percutaneous Bone-Anchored Titanium Prostheses: Toward Achieving Holistic Biointegration

A holistic biointegration of percutaneous bone-anchored metallic prostheses with both hard and soft tissues dictates their longevity in the human body. While titanium (Ti) has nearly solved osseointegration, soft tissue integration of percutaneous metallic prostheses is a perennial problem. Unlike the firm soft tissue sealing in biological percutaneous structures (fingernails and teeth), foreign body response of the skin to titanium (Ti) leads to inflammation, epidermal downgrowth and inferior peri-implant soft tissue sealing. This review discusses various implant surface treatments/texturing and coatings for osseointegration, soft tissue integration, and against bacterial attachment. While surface microroughness by SLA (sandblasting with large grit and acid etched) and porous calcium phosphate (CaP) coatings improve Ti osseointegration, smooth and textured titania nanopores, nanotubes, microgrooves, and biomolecular coatings encourage soft tissue attachment. However, the inferior peri-implant soft tissue sealing compared to natural teeth can lead to peri-implantitis. Toward this end, the application of smart multifunctional bioadhesives with strong adhesion to soft tissues, mechanical resilience, durability, antibacterial, and immunomodulatory properties for soft tissue attachment to metallic prostheses is proposed.

Vascularized 3D Human Skin Models in the Forefront of Dermatological Research

In vitro engineered skin models are emerging as an alternative platform to reduce and replace animal testing in dermatological research. Despite the progress made in recent years, considerable challenges still exist for the inclusion of diverse cell types within skin models. Blood vessels, in particular, are essential in maintaining tissue homeostasis and are one of many primary contributors to skin disease inception and progression. Substantial efforts in the past have allowed the successful fabrication of vascularized skin models that are currently utilized for disease modeling and drugs/cosmetics testing. This review first discusses the need for vascularization within tissue-engineered skin models, highlighting their role in skin grafting and disease pathophysiology. Second, the review spotlights the milestones and recent progress in the fabrication and utilization of vascularized skin models. Additionally, advances including the use of bioreactors, organ-on-a-chip devices, and organoid systems are briefly explored. Finally, the challenges and future outlook for vascularized skin models are addressed.

Biotagging method for animal identification using dissolvable microneedle arrays prepared by customisable moulds

Properly handling animals and understanding their habits are crucial to establish a society where humans and animals coexist. Thus, identifying individual animals, including their possessions, and adequately managing each animal is necessary. Although several conventional identification methods exist, such as the use of ear punch, tattoos, and radio frequency (RF) chips, they require several processes and external apparatus. In this study, we proposed a new biotagging method using a microneedle array for animal identification. Our approach uses dissolvable microneedle arrays as a single patch to deliver dyes directly into the skin layer. Additionally, we developed a new fabrication method for customised female moulds to realise microneedle array patches (MAPs) with patterns of different characters and number. The characteristics and feasibility of the patterned MAPs were confirmed through basic evaluations and animal experiments. Moreover, we confirmed that patterns formed from biotagging using the developed patterned MAPs lasted over one month with clear readability. Finally, we confirmed that our patterned MAPs successfully realised biotagging on rat skin with the designated patterns including characters and number patterns. The proposed method is expected to enable minimally invasive tagging without external equipment or complex processes. In addition, the developed method could be used to embed various tags into the skin of animals and humans in the future.

Single-Cell and Spatial Transcriptomic Analysis of Human Skin Delineates Intercellular Communication and Pathogenic Cells

Epidermal homeostasis is governed by a balance between keratinocyte proliferation and differentiation with contributions from cell-cell interactions, but conserved or divergent mechanisms governing this equilibrium across species and how an imbalance contributes to skin disease are largely undefined. To address these questions, human skin single-cell RNA sequencing and spatial transcriptomics data were integrated and compared with mouse skin data. Human skin cell-type annotation was improved using matched spatial transcriptomics data, highlighting the importance of spatial context in cell-type identity, and spatial transcriptomics refined cellular communication inference. In cross-species analyses, we identified a human spinous keratinocyte subpopulation that exhibited proliferative capacity and a heavy metal processing signature, which was absent in mouse and may account for species differences in epidermal thickness. This human subpopulation was expanded in psoriasis and zinc-deficiency dermatitis, attesting to disease relevance and suggesting a paradigm of subpopulation dysfunction as a hallmark of the disease. To assess additional potential subpopulation drivers of skin diseases, we performed cell-of-origin enrichment analysis within genodermatoses, nominating pathogenic cell subpopulations and their communication pathways, which highlighted multiple potential therapeutic targets. This integrated dataset is encompassed in a publicly available web resource to aid mechanistic and translational studies of normal and diseased skin.

Immune responses, therapeutic anti-tumor effects, and tolerability upon therapeutic HPV16/18 E6/E7 DNA vaccination via needle-free biojector

IMPORTANCE

Respectively, HPV16 and HPV18 cause 50% and 20% of cervical cancer cases globally. Viral proteins E6 and E7 are obligate drivers of oncogenic transformation. We recently developed a candidate therapeutic DNA vaccine, pBI-11, that targets HPV16 and HPV18 E6 and E7. Single-site intramuscular delivery of pBI-11 via a needle elicited therapeutic anti-tumor effects in mice and is now being tested in high-risk human papillomavirus+ head and neck cancer patients (NCT05799144). Needle-free biojectors such as the Tropis device show promise due to ease of administration, high patient acceptability, and the possibility of improved delivery. For example, vaccination of patients with the ZyCoV-D DNA vaccine using the Tropis device is effective against COVID19, well tolerated, and licensed. Here we show that split-dose, multi-site administration and intradermal delivery via the Tropis biojector increase the delivery of pBI-11 DNA vaccine, enhance HPV antigen-specific CD8+ T-cell responses, and improve anti-tumor therapeutic effects, suggesting its translational potential to treat HPV16/18 infection and disease.

Bioengineered skin organoids: from development to applications

Significant advancements have been made in recent years in the development of highly sophisticated skin organoids. Serving as three-dimensional models that mimic human skin, these organoids have evolved into complex structures and are increasingly recognized as effective alternatives to traditional culture models and human skin due to their ability to overcome the limitations of two-dimensional systems and ethical concerns. The inherent plasticity of skin organoids allows for their construction into physiological and pathological models, enabling the study of skin development and dynamic changes. This review provides an overview of the pivotal work in the progression from 3D layered epidermis to cyst-like skin organoids with appendages. Furthermore, it highlights the latest advancements in organoid construction facilitated by state-of-the-art engineering techniques, such as 3D printing and microfluidic devices. The review also summarizes and discusses the diverse applications of skin organoids in developmental biology, disease modelling, regenerative medicine, and personalized medicine, while considering their prospects and limitations.

Pharmacological YAP activation promotes regenerative repair of cutaneous wounds

Chronic cutaneous wounds remain a persistent unmet medical need that decreases life expectancy and quality of life. Here, we report that topical application of PY-60, a small-molecule activator of the transcriptional coactivator Yes-associated protein (YAP), promotes regenerative repair of cutaneous wounds in pig and human models. Pharmacological YAP activation enacts a reversible pro-proliferative transcriptional program in keratinocytes and dermal cells that results in accelerated re-epithelization and regranulation of the wound bed. These results demonstrate that transient topical administration of a YAP activating agent may represent a generalizable therapeutic approach to treating cutaneous wounds.

Ovol1/2 loss-induced epidermal defects elicit skin immune activation and alter global metabolism

Skin epidermis constitutes the outer permeability barrier that protects the body from dehydration, heat loss, and myriad external assaults. Mechanisms that maintain barrier integrity in constantly challenged adult skin and how epidermal dysregulation shapes the local immune microenvironment and whole-body metabolism remain poorly understood. Here, we demonstrate that inducible and simultaneous ablation of transcription factor-encoding Ovol1 and Ovol2 in adult epidermis results in barrier dysregulation through impacting epithelial-mesenchymal plasticity and inflammatory gene expression. We find that aberrant skin immune activation then ensues, featuring Langerhans cell mobilization and T cell responses, and leading to elevated levels of secreted inflammatory factors in circulation. Finally, we identify failure to gain body weight and accumulate body fat as long-term consequences of epidermal-specific Ovol1/2 loss and show that these global metabolic changes along with the skin barrier/immune defects are partially rescued by immunosuppressant dexamethasone. Collectively, our study reveals key regulators of adult barrier maintenance and suggests a causal connection between epidermal dysregulation and whole-body metabolism that is in part mediated through aberrant immune activation.

An agent-based model of tissue maintenance and self-repair

We hypothesized that a system that possesses the capacity for ongoing maintenance of its tissues will necessarily also have the capacity to self-heal following a perturbation. We used an agent-based model of tissue maintenance to investigate this idea, and in particular to determine the extent to which the current state of the tissue must influence cell behavior in order for tissue maintenance and self-healing to be stable. We show that a mean level of tissue density is robustly maintained when catabolic agents digest tissue at a rate proportional to local tissue density, but that the spatial heterogeneity of the tissue at homeostasis increases with the rate at which tissue is digested. The rate of self-healing is also increased by increasing either the amount of tissue removed or deposited at each time step by catabolic or anabolic agents, respectively, and by increasing the density of both agent types on the tissue. We also found that tissue maintenance and self-healing are stable with an alternate rule in which cells move preferentially to tissue regions of low density. The most basic form of self-healing can thus be achieved with cells that follow very simple rules of behavior, provided these rules are based in some way on the current state of the local tissue. Straightforward mechanisms can accelerate the rate of self-healing, as might be beneficial to the organism.

Skin drug delivery using lipid vesicles: A starting guideline for their development

Lipid vesicles can provide a cost-effective enhancement of skin drug absorption when vesicle production process is optimised. It is an important challenge to design the ideal vesicle, since their properties and features are related, as changes in one affect the others. Here, we review the main components, preparation and characterization methods commonly used, and the key properties that lead to highly efficient vesicles for transdermal drug delivery purposes. We stand by size, deformability degree and drug loading, as the most important vesicle features that determine the further transdermal drug absorption. The interest in this technology is increasing, as demonstrated by the exponential growth of publications on the topic. Although long-term preservation and scalability issues have limited the commercialization of lipid vesicle products, freeze-drying and modern escalation methods overcome these difficulties, thus predicting a higher use of these technologies in the market and clinical practice.

Antibody gene transfer treatment drastically improves epidermal pathology in a keratitis ichthyosis deafness syndrome model using male mice

BACKGROUND

Keratitis ichthyosis deafness (KID) syndrome is a rare disorder caused by hemichannel (HC) activating gain-of-function mutations in the GJB2 gene encoding connexin (Cx) 26, for which there is no cure, or current treatments based upon the mechanism of disease causation.

METHODS

We applied Adeno Associated Virus (AAV) mediated mAb gene transfer (AAVmAb) to treat the epidermal features of KID syndrome with a well-characterized HC blocking antibody using male mice of a murine model that replicates the skin pathology of the human disease.

FINDINGS

We demonstrate that in vivo AAVmAb treatment significantly reduced the size and thickness of KID lesions, in addition to blocking activity of mutant HCs in the epidermis in vivo. We also show that AAVmAb treatment eliminated abnormal keratinocyte proliferation and enlarged cell size, decreased apoptosis, and restored the normal distribution of keratin expression.

INTERPRETATION

Our findings reinforce the critical role played by increased HC activity in the skin pathology associated with KID syndrome. They also underscore the clinical potential of anti-HC mAbs coupled with genetic based delivery systems for treating the underlying mechanistic basis of this disorder. Inhibition of HC activity is an ideal therapeutic target in KID syndrome, and the genetic delivery of mAbs targeted against mutant HCs could form the basis of new therapeutic interventions to treat this incurable disease.

FUNDING

Fondazione Telethon grant GGP19148 and University of Padova grant Prot. BIRD187130 to FM; Foundation for Ichthyosis and Related Skin Types (FIRST) and National Institutes of Health grant EY 026911 to TWW.

AUTOPHAGY IN THE EYE: FROM PHYSIOLOGY TO PATHOPHYSOLOGY

Autophagy is a catabolic self-degradative pathway that promotes the degradation and recycling of intracellular material through the lysosomal compartment. Although first believed to function in conditions of nutritional stress, autophagy is emerging as a critical cellular pathway, involved in a variety of physiological and pathophysiological processes. Autophagy dysregulation is associated with an increasing number of diseases, including ocular diseases. On one hand, mutations in autophagy-related genes have been linked to cataracts, glaucoma, and corneal dystrophy; on the other hand, alterations in autophagy and lysosomal pathways are a common finding in essentially all diseases of the eye. Moreover, LC3-associated phagocytosis, a form of non-canonical autophagy, is critical in promoting visual cycle function. This review collects the latest understanding of autophagy in the context of the eye. We will review and discuss the respective roles of autophagy in the physiology and/or pathophysiology of each of the ocular tissues, its diurnal/circadian variation, as well as its involvement in diseases of the eye.

Efficacy of gel containing organic extra virgin olive oil for peristomal skin hygiene: A pilot randomised controlled trial

AIM

To assess the efficacy and safety of the application, during stoma hygiene, of a pH-neutral gel containing organic EVOO (oEVOO) for the maintenance of peristomal skin integrity.

METHOD

Patients with a colostomy or ileostomy were enrolled in a pilot randomized controlled trial and assigned treatment with a pH-neutral gel made from natural products including oEVOO or usual stoma hygiene gel. The primary outcome was three domains of abnormal peristomal skin: Discolouration, Erosion and Tissue overgrowth. Secondary outcomes that were evaluated included skin moisture; oiliness; skin elasticity; water-oil balance; patients' perceptions; difficulty inserting and removing the pouching system; pain, any other chemical, infectious, mechanical, or immunological complications of concern. The intervention lasted 8 weeks.

RESULTS

Twenty-one patients were recruited for the trial and randomly assigned to either the experimental group (n = 12) or the control group (n = 9). The groups did not differ significantly in terms of patient characteristics. No significant differences between groups were identified either at baseline (p = 0.203) or at the end of the intervention (p = 0.397). In the experimental group, domains of abnormal peristomal skin improved after the intervention. The difference observed before and after the intervention was statistically significant (p = 0.031).

CONCLUSION

The use of a gel containing oEVOO has shown similar levels of efficacy and safety to other gels commonly used for peristomal skin hygiene. It is also relevant to highlight that a significant improvement in skin condition was observed in the experimental group before and after the intervention.

Transdermal Transmission Blocking Vaccine for Malaria using a Solid-in-Oil Dispersion

Malaria is a mosquito-borne infectious disease that is widespread in developing countries. Malaria vaccines are important in efforts to eradicate malaria; however, vaccines are usually administered by injection, which requires medical personnel and has a risk of causing infection. Transdermal vaccines can be administered without damaging the skin and thus are ideal for the prevention of malaria. However, the stratum corneum forms a "brick and mortar" like structure in which stratum corneum cells are embedded in a hydrophobic matrix composed of lipids, which strongly inhibits the permeation of hydrophilic substances. In the present study, we designed a transdermal vaccine against vivax malaria using a solid-in-oil (S/O) dispersion. The S/O dispersion of a transmission blocking vaccine candidate, Pvs25 from Plasmodium vivax, showed higher skin penetration than that of the aqueous solution. Mice immunized with the S/O dispersion generated antibodies at similar titers as the mice immunized by injection, over the mid- to long-term. These results provide information for the development of transdermally administered malaria vaccines toward the eradication of malaria.

A Novel Hair Restoration Technology Counteracts Androgenic Hair Loss and Promotes Hair Growth in A Blinded Clinical Trial

Androgenic alopecia (AGA) is a genetically predetermined condition that occurs as a result of stepwise miniaturization of the dermal papilla. During this process, the hair follicle suffers from increasing malnutrition and eventually dies, causing progressive hair loss. We recently highlighted that HIF-1α modulation may counteract hair loss. Here, we aim to demonstrate the positive influence of Tomorrowlabs HIF strengthening factor [HSF] hair restoration technology on hair biology in a monocentric blinded clinical trial over a total period of 9 months. A trial with 20 subjects (4 female and 16 male) and once-daily application of [HSF] hair restoration technology to the scalp was conducted. To assess the tolerability and efficacy of [HSF], testing included dermatological assessment, determination of hair loss by counting after combing, macro images of the head and TrichoScan evaluation of hair density as well as the proportion of anagen hair versus telogen hair. The clinical data show Tomorrowlabs [HSF] hair restoration to be safe and effective to counteract AGA. The use of Tomorrowlabs [HSF] hair restoration resulted in improvements in the clinical parameters of hair quality such as thickness (+7.2%), hair density (+14.3%) and shine and elasticity (+20.3%) during the test period. The effectiveness of the test product was further determined by a significant reduction in hair loss of an average of 66.8% in treatment-responsive subjects after 6 months and an increase in hair growth reaching up to 32.5%, with an average percentage change of 8.4% in all participants and 10.8% in the responsive patients (85% of the study cohort) after 9 months on TrichoScan evaluation. The hair growth cycle was harmonized with the result of an average anagen hair percentage increase of +8.0% and telogen hair percentage reduction of -14.0% shown in the test area. Applicable for both sexes in an alcohol-free formulation, beneficial to scalp health and free of complications or side effects, this novel product provides objectively measurable results counteracting hair loss paired with an improved look and feel of the hair.

Mucosa-interfacing electronics

The surface mucosa that lines many of our organs houses myriad biometric signals and, therefore, has great potential as a sensor-tissue interface for high-fidelity and long-term biosensing. However, progress is still nascent for mucosa-interfacing electronics owing to challenges with establishing robust sensor-tissue interfaces; device localization, retention and removal; and power and data transfer. This is in sharp contrast to the rapidly advancing field of skin-interfacing electronics, which are replacing traditional hospital visits with minimally invasive, real-time, continuous and untethered biosensing. This Review aims to bridge the gap between skin-interfacing electronics and mucosa-interfacing electronics systems through a comparison of the properties and functions of the skin and internal mucosal surfaces. The major physiological signals accessible through mucosa-lined organs are surveyed and design considerations for the next generation of mucosa-interfacing electronics are outlined based on state-of-the-art developments in bio-integrated electronics. With this Review, we aim to inspire hardware solutions that can serve as a foundation for developing personalized biosensing from the mucosa, a relatively uncharted field with great scientific and clinical potential.

Use of hormone-specific antibody probes for differential labeling of contributor cell populations in trace DNA mixtures

A significant proportion of casework analyzed by forensic science laboratories is often "touch" or trace forensic DNA evidence, which is deposited through physical contact and is comprised of sloughed epidermal cells. These samples can be challenging to analyze due to low DNA concentrations, frequent degradation, and the presence of cells from multiple individuals in the same sample. To address these challenges, we investigated a new approach for characterizing trace evidence prior to DNA profiling that labels epidermal cells with antibody probes targeting hormone molecules testosterone and dihydrotestosterone (DHT). The goal was to test whether cell populations derived from separate individuals showed different binding efficiencies to hormone probes and, thus, could be used to detect the presence of multiple cell populations. Additionally, we investigated whether antibody probes could be used to isolate contributor cell populations from an epidermal cell mixture and facilitate deconvolution of mixed DNA profiles recovered from touch/trace evidence. Results showed that cell populations from some individuals could differentiated in trace samples based on fluorescence histograms following probe labeling. However, certain pairs of contributors showed largely or completely overlapping histogram profiles and could not be resolved. Preliminary efforts to separate cell populations that could be differentiated with hormone probes with fluorescence-activated cell sorting (FACS) coupled to DNA profiling and probabilistic modeling indicated that it is possible to enrich contributor cell populations from touch/trace samples and produce more probative DNA profiles compared to the original mixture sample. The variability in labeling, differentiation, and physical separation of cell populations may be impacted by similarities in biochemical profiles across some contributors as well as imbalance of contributor DNA quantities in certain mixtures as is typical in casework involving touch/trace evidence. Ultimately, screening and separation of trace DNA samples with this approach may be presumptive and constrained by sample-specific parameters of the original mixture.

Transcription Factors Runx1 and Runx3 Suppress Keratin Expression in Undifferentiated Keratinocytes

The Runt-related transcription factor (Runx) family has been suggested to play roles in stem cell regulation, tissue development, and oncogenesis in various tissues/organs. In this study, we investigated the possible functions of Runx1 and Runx3 in keratinocyte differentiation. Both Runx1 and Runx3 proteins were detected in primary cultures of mouse keratinocytes. Proteins were localized in the nuclei of undifferentiated keratinocytes but translocated to the cytoplasm of differentiated cells. The siRNA-mediated inhibition of Runx1 and Runx3 expression increased expression of keratin 1 and keratin 10, which are early differentiation markers of keratinocytes. In contrast, overexpression of Runx1 and Runx3 suppressed keratin 1 and keratin 10 expression. Endogenous Runx1 and Runx3 proteins were associated with the promoter sequences of keratin 1 and keratin 10 genes in undifferentiated but not differentiated keratinocytes. In mouse skin, the inhibition of Runx1 and Runx3 expression by keratinocyte-specific gene targeting increased the ratios of keratin 1- and keratin 10-positive cells in the basal layer of the epidermis. On the other hand, inhibition of Runx1 and Runx3 expression did not alter the proliferation capacity of cultured or epidermal keratinocytes. These results suggest that Runx1 and Runx3 likely function to directly inhibit differentiation-induced expression of keratin 1 and keratin 10 genes but are not involved in the regulation of keratinocyte proliferation.

A detailed insight on the molecular and cellular mechanism of action of the antifungal drugs used in the treatment of superficial fungal infections

Background:

Dermatomycosis, a type of fungal infection that can infect human skin, hair, and nails; day by day the growth of fungal infections ranging from superficial to systemic infection is alarming. Common causative agents included are Candida, Cryptococcus, Aspergillus, and Pneumocystis species.

Objective:

The effective treatment of the fungal infection includes the use of proper antifungal drug therapy. Antifungal drugs are classified into various classes. This paper focuses on understanding and interpreting the detailed molecular and cellular mechanism of action of various classes of an anti-fungal drug along with their important characteristics along with the safety and efficacy data of individual drugs of the particular class.

Methods:

The data selection for carrying out the respective study has been done by studying the combination of review articles and research papers from different databases like Research Gate, PubMed, MDPI, Elsevier, Science Direct, and Med Crave ranging from the year 1972 to 2019 by using the keywords like “anti-fungal agents”, “dermatophytes”, “cutaneous candidiasis”, “superficial fungal infections”, “oral candidiasis”, “amphotericin”, “echinocandins”, “azoles”, “polyenes” “ketoconazole”, “terbinafine”, “griseofulvin”, “azoles”.

Result:

Based on interpretation, we have concluded that the different classes of antifungal drugs follow the different mechanisms of action and target the fungal cell membrane, and are efficient in reducing fungal disease by their respective mechanism.

Conclusion:

The prevention and cure of fungal infections can be done by oral or topical antifungal drugs that aim to destroy the fungal cell membrane. These drugs show action by their respective pathways that are either preventing the formation of ergosterol or squalene or act by inhibiting β-1,3-glucan synthase enzyme. All the drugs are effective in treating fungal infections.

In vivo topical gene therapy for recessive dystrophic epidermolysis bullosa: a phase 1 and 2 trial

Recessive dystrophic epidermolysis bullosa (RDEB) is a lifelong genodermatosis associated with blistering, wounding, and scarring caused by mutations in COL7A1, the gene encoding the anchoring fibril component, collagen VII (C7). Here, we evaluated beremagene geperpavec (B-VEC), an engineered, non-replicating COL7A1 containing herpes simplex virus type 1 (HSV-1) vector, to treat RDEB skin. B-VEC restored C7 expression in RDEB keratinocytes, fibroblasts, RDEB mice and human RDEB xenografts. Subsequently, a randomized, placebo-controlled, phase 1 and 2 clinical trial (NCT03536143) evaluated matched wounds from nine RDEB patients receiving topical B-VEC or placebo repeatedly over 12 weeks. No grade 2 or above B-VEC-related adverse events or vector shedding or tissue-bound skin immunoreactants were noted. HSV-1 and C7 antibodies sometimes presented at baseline or increased after B-VEC treatment without an apparent impact on safety or efficacy. Primary and secondary objectives of C7 expression, anchoring fibril assembly, wound surface area reduction, duration of wound closure, and time to wound closure following B-VEC treatment were met. A patient-reported pain-severity secondary outcome was not assessed given the small proportion of wounds treated. A global assessment secondary endpoint was not pursued due to redundancy with regard to other endpoints. These studies show that B-VEC is an easily administered, safely tolerated, topical molecular corrective therapy promoting wound healing in patients with RDEB.

Targeting mitochondria in dermatological therapy: Beyond oxidative damage and skin aging

INTRODUCTION

The analysis of the role of the mitochondria in oxidative damage and skin aging is a significant aspect of dermatological research. Mitochondria generate most reactive oxygen species (ROS); however, excessive ROS are cytotoxic and DNA-damaging and promote (photo-)aging. ROS also possesses key physiological and regulatory functions and mitochondrial dysfunction is prominent in several skin diseases including skin cancers. Although many standard dermatotherapeutics modulate mitochondrial function, dermatological therapy rarely targets the mitochondria. Accordingly, there is a rationale for "mitochondrial dermatology"-based approaches to be applied to therapeutic research.

AREAS COVERED

This paper examines the functions of mitochondria in cutaneous physiology beyond energy (ATP) and ROS production. Keratinocyte differentiation and epidermal barrier maintenance, appendage morphogenesis and homeostasis, photoaging and skin cancer are considered. Based on related PubMed search results, the paper evaluates thyroid hormones, glucocorticoids, Vitamin D3 derivatives, retinoids, cannabinoid receptor agonists, PPARγ agonists, thyrotropin, and thyrotropin-releasing hormone as instructive lead compounds. Moreover, the mitochondrial protein MPZL3 as a promising new drug target for future "mitochondrial dermatology" is highlighted.

EXPERT OPINION

Future dermatological therapeutic research should have a mitochondrial medicine emphasis. Focusing on selected lead agents, protein targets, in silico drug design, and model diseases will fertilize a mito-centric approach.

Three-Dimensional Skin Tissue Printing with Human Skin Cell Lines and Mouse Skin-Derived Epidermal and Dermal Cells

Since the skin covers most surfaces of the body, it is susceptible to damage, which can be fatal depending on the degree of injury to the skin because it defends against external attack and protects internal structures. Various types of artificial skin are being studied for transplantation to repair damaged skin, and recently, the production of replaceable skin using three-dimensional (3D) bioprinting technology has also been investigated. In this study, skin tissue was produced using a 3D bioprinter with human skin cell lines and cells extracted from mouse skin, and the printing conditions were optimized. Gelatin was used as a bioink, and fibrinogen and alginate were used for tissue hardening after printing. Printed skin tissue maintained a survival rate of 90% or more when cultured for 14 days. Culture conditions were established using 8 mM calcium chloride treatment and the skin tissue was exposed to air to optimize epidermal cell differentiation. The skin tissue was cultured for 14 days after differentiation induction by this optimized culture method, and immunofluorescent staining was performed using epidermal cell differentiation markers to investigate whether the epidermal cells had differentiated. After differentiation, loricrin, which is normally found in terminally differentiated epidermal cells, was observed in the cells at the tip of the epidermal layer, and cytokeratin 14 was expressed in the lower cells of the epidermis layer. Collectively, this study may provide optimized conditions for bioprinting and keratinization for three-dimensional skin production.

Hydrogen-Rich Water Prevents Dehydration-Induced Cellular Oxidative Stress and Cell Death in Human Skin Keratinocytes

Hypohydration is linked to increased risk of a variety of diseases and can be life-threatening, especially in elderly populations. Dehydration induces cellular damage partially through the production of reactive oxygen species (ROS) in cells, tissues and organs. Hydrogen molecules are known to convert ROS to harmless water. Therefore, theoretically hydrogen-rich water (HW) might eliminate dehydration-induced ROS and reverse its harmful effects in cells. In this in vitro study, we demonstrated that air-drying for 5 min could induce ROS generation in both nucleus and cytoplasm of human keratinocytes HaCaT as quantified by CellROX® Green/Orange reagents (Thermo Fisher Scientific, Waltham, Massachusetts, U.S.), respectively. Conversely, when the air-drying time was increased to 10 and 20 min, HaCaT cells lost the ability to produce ROS. Scanning electron microscopic (SEM) images showed that 10 min air-drying could induce severe membrane damage in HaCaT cells. PrestoBlue assay showed that, when HaCaT cells were air-dried for 20 min, cell viability was decreased to 27.6% of the control cells 48 h later. However, once HaCaT cells were pretreated with HW-prepared media, dehydration-induced intracellular ROS, cell membrane damage and cell death were significantly reduced as compared with double distilled water (DDW) under the same conditions. In conclusion, our data suggested that HW can decrease dehydration-induced harmful effects in human cells partially through its antioxidant capacity.

Hypoxia Preconditioned Serum (HPS)-Hydrogel Can Accelerate Dermal Wound Healing in Mice—An In Vivo Pilot Study

The ability to use the body’s resources to promote wound repair is increasingly becoming an interesting area of regenerative medicine research. Here, we tested the effect of topical application of blood-derived hypoxia preconditioned serum (HPS) on wound healing in a murine wound model. Alginate hydrogels loaded with two different HPS concentrations (10 and 40%) were applied topically on full-thickness wounds created on the back of immunocompromised mice. We achieved a significant dose-dependent wound area reduction after 5 days in HPS-treated groups compared with no treatment (NT). On average, both HPS-10% and HPS-40% -treated wounds healed 1.4 days faster than NT. Healed tissue samples were investigated on post-operative day 15 (POD 15) by immunohistology and showed an increase in lymphatic vessels (LYVE-1) up to 45% with HPS-40% application, while at this stage, vascularization (CD31) was comparable in the HPS-treated and NT groups. Furthermore, the expression of proliferation marker Ki67 was greater on POD 15 in the NT-group compared to HPS-treated groups, in accordance with the earlier completion of wound healing observed in the latter. Collagen deposition was similar in all groups, indicating lack of scar tissue hypertrophy as a result of HPS-hydrogel treatment. These findings show that topical HPS application is safe and can accelerate dermal wound healing in mice.

Development challenges for carcinogenicity risk assessments of topical drugs

The nonclinical safety package to support development and approval of drugs intended to be administered by topical application generally follows International Council for Harmonisation multidisciplinary 3 (ICH M3) and topic specific safety (ICH S) guidances. However, some aspects of topical drug development may require case-by-case determination of nonclinical safety strategies. The necessity to conduct a dermal rodent carcinogenicity study is one such example that is not considered an obligate component of a nonclinical safety data package for drug approval. While absence of systemic exposure, as stated in ICH M3, is a primary reason to forego a dermal carcinogenicity assessment, there may also be other factors for consideration in determining the need for a life-time carcinogencity study by dermal route to aid in the overall human cancer risk assessment. We therefore reviewed nonclinical carcinogencity data packages from drugs approved by the FDA or PMDA over a ~25 year time period to evaluate outcomes of oral versus topical carcinogencity studies and to understand their utility for informing the overall human risk assessment. We also discuss various other properties of topical small molecules that could impact the decisions to conduct a dermal life-time rodent carcinogenicity study. Collectively, the need to conduct 2-year dermal carcinogenicity studies in rodents should be determined case-by-case and consider scientific factors such existing systemic toxicity and carcinogenicity study data, anticipated drug exposures in skin, skin evaluation from the chronic minipig toxicity study, and genetic toxicity profile.

Calcium Signaling in the Photodamaged Skin: In Vivo Experiments and Mathematical Modeling

The epidermis forms an essential barrier against a variety of insults. The overall goal of this study was to shed light not only on the effects of accidental epidermal injury, but also on the mechanisms that support laser skin resurfacing with intra-epidermal focal laser-induced photodamage, a widespread medical practice used to treat a range of skin conditions. To this end, we selectively photodamaged a single keratinocyte with intense, focused and pulsed laser radiation, triggering Ca2+ waves in the epidermis of live anesthetized mice with ubiquitous expression of a genetically encoded Ca2+ indicator. Waves expanded radially and rapidly, reaching up to eight orders of bystander cells that remained activated for tens of minutes, without displaying oscillations of the cytosolic free Ca2+ concentration ([Formula: see text]). By combining in vivo pharmacological dissection with mathematical modeling, we demonstrate that Ca2+ wave propagation depended primarily on the release of ATP, a prime damage-associated molecular patterns (DAMPs), from the hit cell. Increments of the [Formula: see text] in bystander cells were chiefly due to Ca2+ release from the endoplasmic reticulum (ER), downstream of ATP binding to P2Y purinoceptors. ATP-dependent ATP release though connexin hemichannels (HCs) affected wave propagation at larger distances, where the extracellular ATP concentration was reduced by the combined effect of passive diffusion and hydrolysis due to the action of ectonucleotidases, whereas pannexin channels had no role. Bifurcation analysis suggests basal keratinocytes have too few P2Y receptors (P2YRs) and/or phospholipase C (PLC) to transduce elevated extracellular ATP levels into inositol trisphosphate (IP3) production rates sufficiently large to sustain [Formula: see text] oscillations.

Ichthyosis and hereditary cornification disorders in dogs

The stratum corneum (SC), the outermost layer of the epidermis, serves a crucial role in maintaining body hydration and protection from environmental insults. When the stratum corneum is injured or when the genetic blueprints are flawed, the body is at risk of dehydration, secondary infections and allergen sensitization. Advancements in veterinary dermatology have revealed a wide gamut of disease from relatively benign to lethal that specifically arise from flawed structural proteins, enzymes or lipids needed to create the corneocytes and lipid bilayers of the SC. Some conditions closely mimic their human counterparts while others are unique to the dog. This review will focus on forms of ichthyosis in the dog.

The Diverse Manifestations of Regeneration and Why We Need to Study Them

For hundreds of years, the question of why some organisms can regenerate missing body parts while others cannot has remained poorly understood. This has been due in great part to the inability to genetically, molecularly, and cellularly dissect this problem for most of the history of the field. It has only been in the past 20-30 years that important mechanistic advances have been made in methodologies that introduce loss and gain of gene function in animals that can regenerate. However, we still have a very incomplete understanding of how broadly regenerative abilities may be dispersed across species and whether or not such properties share a common evolutionary origin, which may have emerged independently or both. Understanding regeneration, therefore, will require rigorously practiced fundamental, curiosity-driven, discovery research. Expanding the number of research organisms used to study regeneration allows us to uncover aspects of this problem we may not yet know exist and simultaneously increases our chances of solving this long-standing problem of biology.

A Serum Level of Squamous Cell Carcinoma Antigen as a Real-Time Biomarker of Atopic Dermatitis

Background: Although serum levels of squamous cell carcinoma antigen (SCCA) are elevated in atopic dermatitis (AD), their clinical utility has not been fully elucidated. Methods: Thirty-three cases of AD who admitted to our hospital were analyzed. Results: Baseline characteristics on admission were as follows: median age 19 months [interquartile range (IQR), 12-52 months], median objective severity scoring of atopic dermatitis (O-SCORAD) 19.2 (IQR, 4.2-36.0), and median serum SCCA levels 3.2 ng/mL (IQR, 2.1-6.8 ng/mL). O-SCORAD significantly correlated with serum SCCA levels (rs = 0.865, P < 0.001). In 9 cases whose information before and after treatment was available (median interval, 3 days; IQR 2-5 days), median serum SCCA levels significantly decreased from 8.0 to 2.0 ng/mL (P = 0.008) after the treatment. Conclusions: Serum levels of total SCCA rapidly declined in response to the treatment and could be used as a real-time biomarker in childhood AD.

Effect of Rho-Associated Protein Kinase Inhibitors on Epidermal Keratinocytes: A Proposed Application for Burn Wound Healing

Rho-associated protein kinases (ROCKs) affect a variety of cellular functions, including cell attachment, migration, and proliferation. ROCK inhibitors therefore have potential as tools for optimizing cell behavior in tissue engineering applications, including the manufacturing of cultivated epithelial autografts (CEAs) used in the treatment of burn patients. For example, ROCK inhibitors may facilitate earlier engraftment of CEA sheets by increasing the proliferation of skin keratinocytes ex vivo. Nevertheless, the current understanding of ROCK inhibitor action on epidermal keratinocytes is unclear owing to multiple drug formulations, drug concentrations, and cellular function assays having been used. The aim of this review article therefore is to identify consistent patterns of ROCK inhibitor action on human keratinocytes, as well as revealing key knowledge gaps. In doing so, we propose a clearer course of action for pursuing the potential benefits of ROCK inhibitors for the future treatment of burn patients. Impact statement The properties of Rho-associated protein kinase (ROCK) inhibitors are already used clinically within the fields of cardiology, neurology, and ophthalmology. These results encourage the broadening of ROCK inhibitor uses for other clinical applications. With respect to burn patients, ROCK inhibitors may facilitate improvements in patient survival and healing by reducing the time required for generating cultivated epithelial autograft (CEA) sheets from patient biopsies. Nevertheless, varying approaches to studying the effects of ROCK inhibitors on skin cells in vitro have complicated the development of improved protocols. Our review aims to clarify a diverse and growing body of literature as to the potential benefits for burn patients.

Design, Preparation, and Characterization of Effective Dermal and Transdermal Lipid Nanoparticles: A Review

Limited permeability through the stratum corneum (SC) is a major obstacle for numerous skin care products. One promising approach is to use lipid nanoparticles as they not only facilitate penetration across skin but also avoid the drawbacks of conventional skin formulations. This review focuses on solid lipid nanoparticles (SLNs), nanostructured lipid nanocarriers (NLCs), and nanoemulsions (NEs) developed for topical and transdermal delivery of active compounds. A special emphasis in this review is placed on composition, preparation, modifications, structure and characterization, mechanism of penetration, and recent application of these nanoparticles. The presented data demonstrate the potential of these nanoparticles for dermal and transdermal delivery.

Mouse aging cell atlas analysis reveals global and cell type-specific aging signatures

Aging is associated with complex molecular and cellular processes that are poorly understood. Here we leveraged the Tabula Muris Senis single-cell RNA-seq data set to systematically characterize gene expression changes during aging across diverse cell types in the mouse. We identified aging-dependent genes in 76 tissue-cell types from 23 tissues and characterized both shared and tissue-cell-specific aging behaviors. We found that the aging-related genes shared by multiple tissue-cell types also change their expression congruently in the same direction during aging in most tissue-cell types, suggesting a coordinated global aging behavior at the organismal level. Scoring cells based on these shared aging genes allowed us to contrast the aging status of different tissues and cell types from a transcriptomic perspective. In addition, we identified genes that exhibit age-related expression changes specific to each functional category of tissue-cell types. Altogether, our analyses provide one of the most comprehensive and systematic characterizations of the molecular signatures of aging across diverse tissue-cell types in a mammalian system.

Modeling drug transport within the viable skin - a review

INTRODUCTION

In the past, mathematical modeling of the transport of transdermal drugs has been primarily focused on the stratum corneum. However, the development of pharmaceutical technologies, such as chemical enhancers, iontophoresis, and microneedles, has led to two outcomes; an increase in permeability in the stratum corneum or the ability to negate the layer entirely. As a result, these outcomes have made the transport of a solute in the viable skin far more critical when studying transdermal drug delivery.

AREAS COVERED

The review will explicitly show the various attempts to model drug transport within the viable skin. Furthermore, a brief review will be conducted on the different models that explain stratum corneum transport, microneedle dynamics and estimation of the diffusion coefficient.

EXPERT OPINION

Future development of mathematical models requires the focus to be changed from traditional diffusion-based tissue models to more sophisticated three-dimensional models that incorporate the physiology of the skin.

A potent antagonist antibody targeting connexin hemichannels alleviates Clouston syndrome symptoms in mutant mice

BACKGROUND

Numerous currently incurable human diseases have been causally linked to mutations in connexin (Cx) genes. In several instances, pathological mutations generate abnormally active Cx hemichannels, referred to also as "leaky" hemichannels. The goal of this study was to assay the in vivo efficacy of a potent antagonist antibody targeting Cx hemichannels.

METHODS

We employed the antibody to treat Cx30A88V/A88V adult mutant mice, the only available animal model of Clouston syndrome, a rare orphan disease caused by Cx30 p.A88V leaky hemichannels. To gain mechanistic insight into antibody action, we also performed patch clamp recordings, Ca2+ imaging and ATP release assay in vitro.

FINDINGS

Two weeks of antibody treatment sufficed to repress cell hyperproliferation in skin and reduce hypertrophic sebaceous glands (SGs) to wild type (wt) levels. These effects were obtained whether mutant mice were treated topically, by application of an antibody cream formulation, or systemically, by intraperitoneal antibody injection. Experiments with mouse primary keratinocytes and HaCaT cells revealed the antibody blocked Ca2+ influx and diminished ATP release through leaky Cx30 p.A88V hemichannels.

INTERPRETATION

Our results show anti-Cx antibody treatment was effective in vivo and sufficient to counteract the effects of pathological connexin expression in Cx30A88V/A88V mice. In vitro experiments suggest antibodies gained control over leaky hemichannels and contributed to restoring epidermal homeostasis. Therefore, regulating cell physiology by antibodies targeting the extracellular domain of Cxs may enforce an entirely new therapeutic strategy. These findings support the further development of antibodies as drugs to address unmet medical needs for Cx-related diseases. FUND: Fondazione Telethon, GGP19148; University of Padova, SID/BIRD187130; Consiglio Nazionale delle Ricerche, DSB.AD008.370.003\TERABIO-IBCN; National Science Foundation of China, 31770776; Science and Technology Commission of Shanghai Municipality, 16DZ1910200.

Analysis of the Status of the Cutaneous Endogenous and Exogenous Antioxidative System of Smokers and the Short-Term Effect of Defined Smoking Thereon

The daily consumption of tobacco products leads to a boost in free radical production in tissues, promoting the risk for malignancies, metabolic alterations and chronic-inflammatory diseases. This study aimed to broaden the knowledge of the status of the antioxidative (AO) system in the skin, compared to the blood, of healthy appearing smokers. Both, the basic status compared to non-smokers and the short-term impact of controlled cigarette consumption in smokers were analyzed. Our study showed that the basic level of the AO system of smokers significantly differed from that of non-smokers. As determined by resonant Raman spectroscopy (RRS), the levels of exogenous AOs were decreased in both, the skin, in vivo (β-carotene and lycopene), and blood plasma (β-carotene only). In contrast, the levels of glutathione (GSH), the prototypical endogenous AO, which were analyzed by fluorimetric assays in cutaneous tape strips and blood plasma, were increased in the skin, although unchanged in the blood of smokers. Elevated cutaneous GSH levels were reflected by an elevated overall radical scavenging activity in the skin, as quantified by non-invasive electron paramagnetic resonance (EPR) spectroscopy. Analysis of the expression of selected stress-associated genes in blood immune cells by quantitative RT-PCR in subgroups of non-smokers and smokers additionally demonstrated the downregulation of AKR1C2 in smokers, and its negative correlation with blood plasma levels of the protective immune mediator interleukin-22, assessed by the ELISA technique. Controlled cigarette consumption did not alter exogenous or endogenous AOs in the skin of smokers, but decreased lycopene levels in blood plasma. Moreover, there was a decline in blood IL-22 levels, while no relevant response of blood cell gene expressions was found after the considered short time. Our data therefore demonstrate a strengthened endogenous AO status in the skin of smokers, which may indicate a long-term adaptation to chronic oxidative stress in this specific organ. While this effect was not clearly visible in the blood, this compartment seems to be useful as an immediate indicator of the body's AO consumption. Moreover, decreased levels of AKR1C2, which we show for the first time to be expressed in immune cells, may be a candidate marker for long-term smoking. In addition, this study demonstrates that the rate constant of a spin probe decline determined by EPR spectroscopy mainly represents the endogenous AO status of a tissue.

ATP2A2 SINE Insertion in an Irish Terrier with Darier Disease and Associated Infundibular Cyst Formation

A 4-month-old female Irish Terrier presented with a well demarcated ulcerative and crusting lesion in the right ear canal. Histological analysis revealed epidermal hyperplasia with severe acantholysis affecting all suprabasal layers of the epidermis, which prompted a presumptive diagnosis of canine Darier disease. The lesion was successfully treated by repeated laser ablation of the affected epidermis. Over the course of three years, the dog additionally developed three dermal nodules of up to 4 cm in diameter that were excised and healed without complications. Histology of the excised tissue revealed multiple infundibular cysts extending from the upper dermis to the subcutis. The cysts were lined by squamous epithelium, which presented with abundant acantholysis of suprabasal keratinocytes. Infundibular cysts represent a novel finding not previously reported in Darier patients. Whole genome sequencing of the affected dog was performed, and the functional candidate genes for Darier disease (ATP2A2) and Hailey-Hailey disease (ATP2C1) were investigated. The analysis revealed a heterozygous SINE insertion into the ATP2A2 gene, at the end of intron 14, close to the boundary of exon 15. Analysis of the ATP2A2 mRNA from skin of the affected dog demonstrated a splicing defect and marked allelic imbalance, suggesting nonsense-mediated decay of the resulting aberrant transcripts. As Darier disease in humans is caused by haploinsufficiency of ATP2A2, our genetic findings are in agreement with the clinical and histopathological data and support the diagnosis of canine Darier disease.

A physiologically active interpenetrating collagen network that supports growth and migration of epidermal keratinocytes: zinc-polyP nanoparticles integrated into compressed collagen

It is demonstrated that polyphosphate, as a component in wound healing mats together with Zn²⁺, is essential for growth and migration of skin keratinocytes.

The exercise cytokine interleukin-15 rescues slow wound healing in aged mice

Impaired wound healing in elderly individuals increases infection risk and prolongs surgical recovery, but current treatment options are limited. Low doses of interleukin-15 (IL-15) that mimic exercise responses in the circulation improve skin structure and increase mitochondria in uninjured aged skin, suggesting that IL-15 is an essential mitochondrial signal for healing that is lost during aging. Here we used gene microarray analysis of old and young murine epidermal stem cells and demonstrate that aging results in a gene signature characteristic of bioenergetic dysfunction. Intravenous IL-15 treatment rescued chronological aging-induced healing defects and restored youthful wound closure in old, sedentary mice. Additionally, exercise-mediated improvements in the healing of aged skin depend upon circulating IL-15. We show that IL-15 induces signal transducer and activator of transcription 3 (STAT3) signaling characteristic of young animals, reduces markers of growth arrest, and increases keratinocyte and fibroblast growth. Moreover, exercise or exercise-mimicking IL-15 treatment rescued the age-associated decrease in epidermal mitochondrial complex IV activity. Overall, these results indicate that IL-15 or its analogs represent promising therapies for treating impaired wound healing in elderly patients.

Near-Infrared Spectroscopy to Monitor Nutritional Status of Neonates: A Review

The World Health Organization reported that half or more of all under five deaths were caused by undernutrition in developing countries, with the majority of these deaths occurring in the first week of life. Even if the undernourished neonates manage to survive, they are exposed to long-term health impacts, including obesity, cardiovascular disease, and hypertension. Along with those health-impacts they can be exposed to risks related to detrimental early development, such as physical impairment, stunting, brain dysfunction, and reduced cognitive development. Body fat percentage has been recognized to be closely associated with undernutrition in neonates. In this article, the potential of near infrared spectroscopy (NIRS), along with previous methods to measure body fat in neonates, is reviewed and discussed.

The Impact of Herbal Products in the Prevention, Regeneration and Delay of Skin Aging

Skin aging is a complex process induced by intrinsic and extrinsic factors and causes alterations to the structural and functional aspects of the skin. Skin aging affects patients physically and physiologically. Understanding the process of skin aging can provide new knowledge on how to attenuate or reduce skin disorder symptoms. Herbs have been used for ages to prevent and treat skin aging, yet there are growing interests by researchers in this field globally. Various strategies have been developed for improving the quality and effectivity of herbal skin care products, both for topical and oral applications. This review will provide an overview of the relationship between herbal skin care products and the skin aging process.

Role and Therapeutic Targeting of the PI3K/Akt/mTOR Signaling Pathway in Skin Cancer: A Review of Current Status and Future Trends on Natural and Synthetic Agents Therapy

The mammalian or mechanistic target of rapamycin (mTOR) and associated phosphatidyl-inositiol 3-kinase (PI3K)/protein kinase B (Akt) pathways regulate cell growth, differentiation, migration, and survival, as well as angiogenesis and metabolism. Dysregulation of these pathways is frequently associated with genetic/epigenetic alterations and predicts poor treatment outcomes in a variety of human cancers including cutaneous malignancies like melanoma and non-melanoma skin cancers. Recently, the enhanced understanding of the molecular and genetic basis of skin dysfunction in patients with skin cancers has provided a strong basis for the development of novel therapeutic strategies for these obdurate groups of skin cancers. This review summarizes recent advances in the roles of PI3K/Akt/mTOR and their targets in the development and progression of a broad spectrum of cutaneous cancers and discusses the current progress in preclinical and clinical studies for the development of PI3K/Akt/mTOR targeted therapies with nutraceuticals and synthetic small molecule inhibitors.

Mitochondria's Role in Skin Ageing

Skin ageing is the result of a loss of cellular function, which can be further accelerated by external factors. Mitochondria have important roles in skin function, and mitochondrial damage has been found to accumulate with age in skin cells, but also in response to solar light and pollution. There is increasing evidence that mitochondrial dysfunction and oxidative stress are key features in all ageing tissues, including skin. This is directly linked to skin ageing phenotypes: wrinkle formation, hair greying and loss, uneven pigmentation and decreased wound healing. The loss of barrier function during skin ageing increases susceptibility to infection and affects wound healing. Therefore, an understanding of the mechanisms involved is important clinically and also for the development of antiageing skin care products.

Insights into autophagy machinery in cells related to skin diseases and strategies for therapeutic modulation

Autophagy, literally meaning "self-eating," is a highly conserved process that is part of the eukaryotic cell cycle. Morphologically, the double membrane contains vesicles with phagocytic components known as autophagosomes. Autophagy is often used as a cellular stress response and quality control mechanisms are used to maintain cell survival. Survival is facilitated by providing energy and metabolic precursors as well as removing damaged proteins or organelles. Moreover, autophagy refers to organelles fused together with part of the cell cytoplasm with a double or multi-membrane structure called phagosome. Research has demonstrated that autophagy is an important mediator of cell fate and has effects on inflammation, pathogen clearance, and antigen presentation. In recent years, studies discussing autophagy have increased in number. Nevertheless, only a small amount of research has considered the impact of autophagy on the pathogenesis of skin diseases. The skin is the largest organ of the body, with a surface area of around two square metre; it is the first line of defense against numerous environmental insults, including ultraviolet radiation, pathogens, mechanical stresses, and toxic chemicals. Autophagy is thought to be a vital modality for endogenous defenses against environmental derangements. This review provides an overview of autophagy machinery in keratinocytes, skin fibroblasts, melanocytes related to skin diseases as well as strategies for therapeutic modulation, for the future development of treatment for skin diseases.