Connexin 43 Mutations Lead to Increased Hemichannel Functionality in Skin Disease

Gap junctional channels are specialized components of the cellular membrane that allow the intercellular passage of small metabolites, ions, and second messengers to maintain homeostasis. They are comprised of members of the connexin gene family that encode a wide array of proteins that are expressed in nearly every tissue type. Cx43 is perceived to be the most broadly expressed connexin in humans, with several genetic skin diseases being linked to Cx43 mutations specifically. These mutations, in large, produce a gain of functional hemichannels that contribute to the phenotypes of Erythrokeratoderma Variabilis et Progressiva (EKVP), Palmoplantar Keratodemra Congenital Alopecia-1 (PPKCA1), and others that produce large conductance and increased permselectivity in otherwise quiescent structures. Gaining functional hemichannels can have adverse effects in the skin, inducing apoptosis via Ca²⁺ overload or increased ATP permeability. Here, we review the link between Cx43 and skin disease. We aim to provide insight into the mechanisms regulating the normal and pathophysiological gating of these essential proteins, as well as address current therapeutic strategies. We also demonstrate that transient transfection of neuro-2a (N2a) cells with mutant Cx43 cDNA resulted in increased hemichannel activity compared to wild-type Cx43 and untransfected cells, which is consistent with other studies in the current literature.

Pattern recognition receptors as potential drug targets in inflammatory disorders

Pattern recognition receptors (PRRs) are a key part of the innate immune system, the body's first line of defense against infection and tissue damage. This superfamily of receptors including Toll-like receptors (TLRs), NOD-like receptors (NLRs), C-type lectin-like receptors (CLRs) and RIG-like receptors (RLRs) are responsible for initiation of the inflammatory response by their recognition of molecular patterns present in invading microorganisms (such as bacteria, viruses or fungi) during infection or in molecules released following tissue damage during acute or chronic disease states (such as sepsis or arthritis). These receptors are widely expressed and located on the cell surface, in intracellular compartments or in the cytoplasm can detect a single or subset of molecules including lipoproteins, carbohydrates or nucleic acids. In response, they initiate an intracellular signaling cascade that culminates in the synthesis and release of cytokines, chemokines and vasoactive molecules. These steps are necessary to maintain tissue homeostasis and remove potentially dangerous pathogens. However, during extreme or acute responses or during chronic disease, this can be damaging and even lead to death. Therefore, it is thought that targeting such receptors may offer a therapeutic approach in chronic inflammatory diseases or in cases of acute infection leading to sepsis. Herein, the current knowledge on the molecular biology of PRRs is reviewed along with their association with inflammatory and infectious diseases. Finally, the testing of therapeutic compounds and their future merit as targets is discussed.

Diverse therapeutic efficacies and more diverse mechanisms of nicotinamide

BACKGROUND

Nicotinamide (NAM) is a form of vitamin B3 that, when administered at near-gram doses, has been shown or suggested to be therapeutically effective against many diseases and conditions. The target conditions are incredibly diverse ranging from skin disorders such as bullous pemphigoid to schizophrenia and depression and even AIDS. Similar diversity is expected for the underlying mechanisms. In a large portion of the conditions, NAM conversion to nicotinamide adenine dinucleotide (NAD⁺) may be a major factor in its efficacy. The augmentation of cellular NAD⁺ level not only modulates mitochondrial production of ATP and superoxide, but also activates many enzymes. Activated sirtuin proteins, a family of NAD⁺-dependent deacetylases, play important roles in many of NAM's effects such as an increase in mitochondrial quality and cell viability countering neuronal damages and metabolic diseases. Meanwhile, certain observed effects are mediated by NAM itself. However, our understanding on the mechanisms of NAM's effects is limited to those involving certain key proteins and may even be inaccurate in some proposed cases.

AIM OF REVIEW

This review details the conditions that NAM has been shown to or is expected to effectively treat in humans and animals and evaluates the proposed underlying molecular mechanisms, with the intention of promoting wider, safe therapeutic application of NAM.

KEY SCIENTIFIC CONCEPTS OF REVIEW

NAM, by itself or through altering metabolic balance of NAD⁺ and tryptophan, modulates mitochondrial function and activities of many molecules and thereby positively affects cell viability and metabolic functions. And, NAM administration appears to be quite safe with limited possibility of side effects which are related to NAM's metabolites.

Potential of Curcumin in Skin Disorders

Curcumin is a compound isolated from turmeric, a plant known for its medicinal use. Recently, there is a growing interest in the medical community in identifying novel, low-cost, safe molecules that may be used in the treatment of inflammatory and neoplastic diseases. An increasing amount of evidence suggests that curcumin may represent an effective agent in the treatment of several skin conditions. We examined the most relevant in vitro and in vivo studies published to date regarding the use of curcumin in inflammatory, neoplastic, and infectious skin diseases, providing information on its bioavailability and safety profile. Moreover, we performed a computational analysis about curcumin's interaction towards the major enzymatic targets identified in the literature. Our results suggest that curcumin may represent a low-cost, well-tolerated, effective agent in the treatment of skin diseases. However, bypass of limitations of its in vivo use (low oral bioavailability, metabolism) is essential in order to conduct larger clinical trials that could confirm these observations. The possible use of curcumin in combination with traditional drugs and the formulations of novel delivery systems represent a very promising field for future applicative research.

N-Terminal Acetylation and C-Terminal Amidation of Spirulina platensis-Derived Hexapeptide: Anti-Photoaging Activity and Proteomic Analysis

Ultraviolet (UV) irradiation is a potent inducer for skin photoaging. This paper investigated the anti-photoaging effects of the acetylated and amidated hexapeptide (AAH), originally identified from Spirulina platensis, in (Ultraviolet B) UVB-irradiated Human immortalized keratinocytes (Hacats) and mice. The results demonstrated that AAH had much lower toxicity on Hacats than the positive matrixyl (81.52% vs. 5.32%). Moreover, AAH reduced MDA content by 49%; increased SOD, CAT, and GSH-Px activities by 103%, 49%, and 116%, respectively; decreased MMP-1 and MMP-3 expressions by 27% and 29%, respectively, compared to UVB-irradiated mice. Employing isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics, 60 differential proteins were identified, and major metabolic pathways were determined. Network analysis indicated that these differential proteins were mapped into an interaction network composed of two core sub-networks. Collectively, AAH is protective against UVB-induced skin photoaging and has potential application in skin care cosmetics.

The Protective Effect of Mycosporine-Like Amino Acids (MAAs) from Porphyra yezoensis in a Mouse Model of UV Irradiation-Induced Photoaging

The objective of this research was to extract and prepare mycosporine-like amino acids (MAAs) and investigate the mechanism by which they act against UV-induced skin photoaging in Institute of Cancer Research (ICR ) mice. MAAs such as porphyra-334 and shinorine were extracted from Porphyra yezoensis, separated, and purified using column chromatography with SA-2 cation exchange resin. The effects of MAAs on the activity of endogenous antioxidant enzymes, namely total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA) were analyzed in mouse skin tissue. Pathological changes of skin tissue caused by ultraviolet radiation and the arrangement of collagen were observed by Hematoxylin-Eosin (HE) staining and scanning electron microscopy (SEM). Interleukin 1β (IL-1β), IL-6, and IL-10 were detected using the quantitative real-time reverse transcription-polymerase chain reaction (qPCR) and Enzyme Linked Immunosorbent Assay (ELISA). The concentration and expression of these proinflammatory cytokines was associated with the presence of nuclear factor (NF)-κB. The results show that MAA compounds from Porphyra yezoensis could suppress UV-induced photoaging of skin by inhibiting the reduction of endogenous antioxidant enzymes. Compared to the control group, the concentrations of SOD, GSH-Px, and CAT increased significantly in skin tissue homogenate following the external administration of MAAs (p < 0.05, p < 0.01), while the content of MDA decreased significantly (p < 0.05). Meanwhile, the administration of MAAs was associated with down-regulations in the concentration and mRNA expression of NF-κB, IL-1β, IL-6, and IL-10. The results suggest that MAAs could protect skin from photodamage by increasing antioxidant enzyme activities and inhibiting inflammation.

Therapeutic Targeting of the IGF Axis

The insulin like growth factor (IGF) axis plays a fundamental role in normal growth and development, and when deregulated makes an important contribution to disease. Here, we review the functions mediated by ligand-induced IGF axis activation, and discuss the evidence for the involvement of IGF signaling in the pathogenesis of cancer, endocrine disorders including acromegaly, diabetes and thyroid eye disease, skin diseases such as acne and psoriasis, and the frailty that accompanies aging. We discuss the use of IGF axis inhibitors, focusing on the different approaches that have been taken to develop effective and tolerable ways to block this important signaling pathway. We outline the advantages and disadvantages of each approach, and discuss progress in evaluating these agents, including factors that contributed to the failure of many of these novel therapeutics in early phase cancer trials. Finally, we summarize grounds for cautious optimism for ongoing and future studies of IGF blockade in cancer and non-malignant disorders including thyroid eye disease and aging.

The Cytokine TNF Promotes Transcription Factor SREBP Activity and Binding to Inflammatory Genes to Activate Macrophages and Limit Tissue Repair

Cytokine tumor necrosis factor (TNF)-mediated macrophage polarization is important for inflammatory disease pathogenesis, but the mechanisms regulating polarization are not clear. We performed transcriptomic and epigenomic analysis of the TNF response in primary human macrophages and revealed late-phase activation of SREBP2, the master regulator of cholesterol biosynthesis genes. TNF stimulation extended the genomic profile of SREBP2 occupancy to include binding to and activation of inflammatory and interferon response genes independently of its functions in sterol metabolism. Genetic ablation of SREBP function shifted the balance of macrophage polarization from an inflammatory to a reparative phenotype in peritonitis and skin wound healing models. Genetic ablation of SREBP activity in myeloid cells or topical pharmacological inhibition of SREBP improved skin wound healing under homeostatic and chronic inflammatory conditions. Our results identify a function and mechanism of action for SREBPs in augmenting TNF-induced macrophage activation and inflammation and open therapeutic avenues for promoting wound repair.

Fermentation product with new equol-producing Lactobacillus paracasei as a probiotic-like product candidate for prevention of skin and intestinal disorder

BACKGROUND

Equol is a major isoflavone metabolite, and equol-producing bacteria have been isolated and characterized; however, fermentation has been performed with soybean-based products as substrates. Pueraria lobata has been reported as a plant with higher content of isoflavones.

RESULTS

The genome of new equol-producing bacteria, Lactobacillus paracasei JS1, was analyzed. Also, the effect of P. lobata extract fermented with L. paracasei JS1 (FPE) on the skin and intestinal immune response was examined. With gene expression analysis, it was proven that seven skin-related proteins, hyaluronan synthase-1, -2, -3, collagen, elastin, epidermal growth factor, and epidermal growth factor receptor were differentially expressed upon FPE treatment. The messenger RNA expression increased with treatment with the FPE, and a skin moisturizing effect was confirmed by a hematoxylin-eosin staining experiment. In addition, such an experiment showed that proinflammatory cytokines, tumor necrosis factor-α, cyclooxygenase-2, inducible nitric oxide synthase, interleukin-1β, -4, and -6, were reduced in large intestine when treated with FPE.

CONCLUSION

L. paracasei JS1 has the ability to produce equol having beneficial effects on the skin. Moreover, FPE also has an inhibitory effect on inflammation cytokines in the large intestine. Thus, the novel and edible equol-producing L. paracasei JS1 and FPE have thepotential to be developed as nutricosmetic resources. © 2019 Society of Chemical Industry.

The Roles of YAP/TAZ and the Hippo Pathway in Healthy and Diseased Skin

Skin is the largest organ of the human body. Its architecture and physiological functions depend on diverse populations of epidermal cells and dermal fibroblasts. Reciprocal communication between the epidermis and dermis plays a key role in skin development, homeostasis and repair. While several stem cell populations have been identified in the epidermis with distinct locations and functions, there is additional heterogeneity within the mesenchymal cells of the dermis. Here, we discuss the current knowledge of how the Hippo pathway and its downstream effectors Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) contribute to the maintenance, activation and coordination of the epidermal and dermal cell populations during development, homeostasis, wound healing and cancer.

LC/MS/MS analyses of open-flow microperfusion samples quantify eicosanoids in a rat model of skin inflammation

Eicosanoids are lipid-mediator molecules with key roles in inflammatory skin diseases, such as psoriasis. Eicosanoids are released close to the source of inflammation, where they elicit local pleiotropic effects and dysregulations. Monitoring inflammatory mediators directly in skin lesions could provide new insights and therapeutic possibilities. Here, we analyzed dermal interstitial fluid samples obtained by dermal open-flow microperfusion in a rat model of skin inflammation. We developed a solid-phase extraction ultra-HPLC/MS/MS method to reliably and precisely analyze small-volume samples and quantified 11 eicosanoids [thromboxane B2, prostaglandin (PG) E2, PGD2, PGF2α, leukotriene B4, 15-HETE, 12-HETE, 5-HETE, 12-hydroxyeicosapentaenoic acid, 13-HODE, and 17-hydroxydocosahexaenoic acid]. Our method achieved a median intraday precision of approximately 5% and interday precision of approximately 8%. All calibration curves showed excellent linearity between 0.01 and 50 ng/ml (R2 > 0.980). In the rat model, eicosanoids were significantly increased in imiquimod-treated inflamed skin sites compared with untreated control sites. Oral treatment with an anti-inflammatory glucocorticoid decreased eicosanoid concentrations. These results show that a combination of tissue-specific sampling with LC/MS analytics is well suited for analyzing small sample volumes from minimally invasive sampling methods such as open-flow microperfusion or microdialysis to study local inflammation and the effect of treatments in skin diseases.

Cannabinoid Signaling in the Skin: Therapeutic Potential of the "C(ut)annabinoid" System

The endocannabinoid system (ECS) has lately been proven to be an important, multifaceted homeostatic regulator, which influences a wide-variety of physiological processes all over the body. Its members, the endocannabinoids (eCBs; e.g., anandamide), the eCB-responsive receptors (e.g., CB₁, CB₂), as well as the complex enzyme and transporter apparatus involved in the metabolism of the ligands were shown to be expressed in several tissues, including the skin. Although the best studied functions over the ECS are related to the central nervous system and to immune processes, experimental efforts over the last two decades have unambiguously confirmed that cutaneous cannabinoid ("c[ut]annabinoid") signaling is deeply involved in the maintenance of skin homeostasis, barrier formation and regeneration, and its dysregulation was implicated to contribute to several highly prevalent diseases and disorders, e.g., atopic dermatitis, psoriasis, scleroderma, acne, hair growth and pigmentation disorders, keratin diseases, various tumors, and itch. The current review aims to give an overview of the available skin-relevant endo- and phytocannabinoid literature with a special emphasis on the putative translational potential, and to highlight promising future research directions as well as existing challenges.

Galectin 1 in dermatology: current knowledge and perspectives

Galectins are a family of soluble proteins that are widely distributed in nature and bind to a variety of glycoproteins and glycolipids bearing β-galactoside residues. They are involved in highly important processes at the molecular and cellular level in human cutaneous and extracutaneous tissues, and they exert biological effects of paramount importance through their interaction with cytoplasmic and nuclear proteins and the components of the cell surface and extracellular matrix. Galectin 1 (Gal 1), the first galectin isolated, is a noncovalent homodimeric protein with a 14 kDa monomer that contains one carbohydrate-recognition domain (CRD) and preferentially recognizes galactose-β1-4-N-acetyl-glucosamine sequences on N- or O-linked glycans. Gal 1 occurs intracellularly, extracellularly, and on the cell surface. In the last few years Gal 1 has emerged as a multifaceted protein that exerts a wide spectrum of regulatory effects in diverse normal and abnormal tissues and conditions, indicating a tremendous therapeutic potential. This review summarizes current knowledge on the expression of Gal 1 in normal and diseased human skin, its implications in the pathogenesis, diagnosis, and prognosis of cutaneous disorders, and the novel approach to the treatment of these disorders offered by the use of Gal 1 or its inhibitors/antagonists.

Oligonucleotide Molecular Sprinkler for Intracellular Detection and Spontaneous Regulation of mRNA for Theranostics of Scar Fibroblasts

Early diagnosis and timely intervention are key for the successful treatment of skin diseases like abnormal scars. This study introduces a nucleic-acid-based probe (i.e., molecular sprinkler) for the diagnosis and spontaneous regulation of the abnormal expression of fibrosis-related mRNA in scar-derived skin fibroblasts. Using mRNA encoding connective tissue growth factor (CTGF) as the model gene, a probe with three oligonucleotides is constructed, including a recognition sequence complementary to the CTGF mRNA, a siRNA against transforming growth factor receptor I (TGFβRI) as the CTGF mRNA suppressor, and a connecting sequence. The probe can detect CTGF mRNA with a limit of 10 × 10^-9 m and distinguishes scar fibroblasts from normal ones in both 2D and 3D environments. Two days after transfection, the siRNA released from the probe reduces the expression of TGFβRI and, consequently, decreases the cellular expression of CTGF mRNA (up to 70%). This dual-role probe presents opportunities to monitor the TGF- β signaling pathway, screen for drugs that target the CTGF pathway, and determine the role of inhibition of the CTGF pathway in therapeutic efficacy.

Protective Effect of Bovine Elastin Peptides against Photoaging in Mice and Identification of Novel Antiphotoaging Peptides

This study aimed to investigate the protective effects of bovine elastin hydrolysates on UV-induced skin photoaging in mice and to identify the potent antiphotoaging peptides. Results showed that the ingestion of elastin peptides could obviously ameliorate epidermis hyperplasia and fibroblast apoptosis, and increase the content of hydroxyproline and water in photoaging skin in vivo ( p < 0.05). Furthermore, four peptides with elastase inhibitory activity were purified and identified, including GLPY, PY, GLGPGVG, and GPGGVGAL. Interestingly, GLPY and GPGGVGAL exhibited the highest inhibition activity with 58.77% and 42.91% at 10 mΜ, respectively. This might be attributed to the N-terminal Gly, C-terminal Leu, and Pro at the third position of the N-terminus, which showed stronger affinity and interaction with elastase. Moreover, GLPY and GPGGVGAL could also inhibit the apoptosis of fibroblasts effectively at 50 μΜ ( p < 0.01). It suggested that elastin peptides had great potential to prevent and regulate skin photoaging.

Role of STAT3 in skin fibrosis and transforming growth factor beta signalling

Objective

SSc is an autoimmune disease characterized by progressive fibrosis of the skin and internal organs. IL-6 and related cytokines that signal through STAT3 have been implicated in the pathogenesis of SSc and mouse models of fibrosis. The aim of this study was to investigate the efficacy of inhibiting STAT3 in the development of fibrosis in two mouse models of skin fibrosis.

Methods

Biopsy samples of skin from SSc patients and healthy control subjects were used to determine the expression pattern of phosphotyrosyl (pY705)-STAT3. C188-9, a small molecule inhibitor of STAT3, was used to treat fibrosis in the bleomycin-induced fibrosis model and Tsk-1 mice. In vitro studies were performed to determine the extent to which STAT3 regulates the fibrotic phenotype of dermal fibroblasts.

Results

Increased STAT3 and pY705-STAT3 was observed in SSc skin biopsies and in both mouse models of SSc. STAT3 inhibition with C188-9 resulted in attenuated skin fibrosis, myofibroblast accumulation, pro-fibrotic gene expression and collagen deposition in both mouse models of skin fibrosis. C188-9 decreased in vitro dermal fibroblast production of fibrotic genes induced by IL-6 trans-signalling and TGF-β. Finally, TGF-β induced phosphotyrosylation of STAT3 in a SMAD3-dependent manner.

Conclusion

STAT3 inhibition decreases dermal fibrosis in two models of SSc. STAT3 regulates dermal fibroblasts function in vitro and can be activated by TGF-β. These data suggest that STAT3 is a potential therapeutic target for dermal fibrosis in diseases such as SSc.

Clinical and Biological Characterization of Skin Pigmentation Diversity and Its Consequences on UV Impact

Skin color diversity is the most variable and noticeable phenotypic trait in humans resulting from constitutive pigmentation variability. This paper will review the characterization of skin pigmentation diversity with a focus on the most recent data on the genetic basis of skin pigmentation, and the various methodologies for skin color assessment. Then, melanocyte activity and amount, type and distribution of melanins, which are the main drivers for skin pigmentation, are described. Paracrine regulators of melanocyte microenvironment are also discussed. Skin response to sun exposure is also highly dependent on color diversity. Thus, sensitivity to solar wavelengths is examined in terms of acute effects such as sunburn/erythema or induced-pigmentation but also long-term consequences such as skin cancers, photoageing and pigmentary disorders. More pronounced sun-sensitivity in lighter or darker skin types depending on the detrimental effects and involved wavelengths is reviewed.

Staphylococcus epidermidis Activates Aryl Hydrocarbon Receptor Signaling in Human Keratinocytes: Implications for Cutaneous Defense

Bacterial challenge of keratinocytes with the abundant skin commensal Staphylococcus epidermidis induces distinct innate immune responses, but the underlying molecular mechanisms are still emerging. We report that the aryl hydrocarbon receptor (AhR) was activated in human primary keratinocytes infected with S. epidermidis, leading to induction of the AhR-responsive gene cytochrome P450 1A1 (CYP1A1). In addition, functional AhR was required for S. epidermidis-mediated induction of IL-1β expression in keratinocytes. AhR-dependent gene induction of IL-1β and CYP1A1 was mediated by factor(s) < 2 kDa secreted by S. epidermidis. Blockade of the AhR in a 3D organotypic skin equivalent infected with S. epidermidis attenuated the S. epidermidis-induced CYP1A1 and IL-1β expression. Moreover, S. epidermidis also induced expression of IL-1α and of the antimicrobial peptide human β-defensin-3 in an AhR-dependent manner in a 3D skin equivalent. An increased outgrowth of S. epidermidis on the surface of skin explants treated with a specific AhR inhibitor further indicate a pivotal role of the AhR in mediating an epidermal defense response. Taken together, our data expand the role of the AhR in innate immunity and support a previously unappreciated contribution for the AhR in cutaneous defense.

Ocular Adnexal Amyloidosis: A Mass Spectrometric Analysis

PURPOSE

Ocular adnexal amyloidosis (OAA) may represent localized manifestation of an underlying systemic process. Accurate identification of the amyloid fibrils can guide the systemic evaluation and treatment. The aim of this study was to characterize subtypes of OAA using immunohistochemistry and mass spectrometric analysis and to correlate with ocular involvement and systemic association.

DESIGN

Retrospective case series.

METHODS

Review of patients with OAA subtyped by immunohistochemistry and mass spectrometric analysis at the Cleveland Clinic from June 1995 to June 2017.

RESULTS

While immunohistochemistry identified AL amyloid protein in 67% (4/6) of specimens tested, mass spectrometry identified AL amyloid protein in all specimens (10/10). AL lambda was identified in 5 (50%) samples, kappa in 3 (30%), and both kappa and lambda light chains in 2 (20%). The 5 cases of conjunctival amyloidosis were either AL lambda only (3 cases) or both lambda and kappa (2 cases). There were 3 cases that had associated systemic involvement. Two of these had eyelid skin involvement and AL kappa amyloidosis and the other patient had uveal involvement and AL lambda amyloidosis.

CONCLUSIONS

Primary amyloidosis-AL is the most common form diagnosed by mass spectrometric analysis in patients with OAA. Immunohistochemistry is ineffective in the characterization of the amyloid deposits in a significant number of cases. Evaluation to exclude systemic involvement or associated underlying lymphoproliferative disorder is warranted.

Skin Care Products: Age-Appropriate Cosmetics

In order to maintain skin in "good condition" one can use cosmetic products. Importantly, those skin care products should fulfil specific requirements for specific life phases and specific skin conditions. In this review, we focused on 2 different age groups - namely, infants and the elderly - as well as on 2 specific skin conditions occurring in both age groups - very dry skin (Xerosis) and hyperhydrated skin (diaper rash). The goal in both conditions should be to maintain skin surface in its physiological acidic state, which is in turn crucial for the permeability barrier function, stratum corneum integrity/cohesion and antimicrobial defense. Skin care products formulated with an effective buffer system at a more acidic pH, for example 4, may be the best option to improve the acid mantle and skin barrier function and thus keep the skin in "good condition."

pH and Microbial Infections

Maintenance of an acidic stratum corneum pH is a major component of the skin's protective system and creates a hostile environment for colonization with pathogenic microorganisms. This barrier can however be overcome on healthy and in particular on compromised skin. Mycosis, diaper/incontinence dermatitis and wound healing are examples of cases where microbial infection is promoted by the altered skin conditions or environment. Fungi have a complex system that senses ambient pH that leads to metabolic responses allowing adhesion, growth and invasion, as microbial metabolites further increase skin pH resulting in a clinically manifest infection (mycosis). Diabetic patients with a higher pH in intertriginous areas are particularly vulnerable to candidiasis. In diaper and incontinence dermatitis, the increase in skin pH and damage to the skin barrier function is triggered by the contact with urine and faeces with or without occlusion and maintained by host and microbial enzymes and metabolites. This leads to the reduction of the protective resident microflora and fungal overgrowth, mostly with Candida albicans. Skin care with slightly acidic products may help to prevent and treat this kind of dermatitis. Wound healing is a complex sequence of biologic events correlated with ambient pH, which influences the different phases of the healing process. The pH determines the appropriate activity of immune cells and key enzymes as well as biofilm formation. Chronic wounds emerging from the disruption of the healing process are characterized by a neutral to slightly alkaline pH and may benefit from wound pH monitoring and therapeutic acidification.

Buffering Capacity

Each biological system possesses a widely unrecognized buffer system to maintain acid-base balance to a specific pH. Our lives are dependent on the functioning of buffer systems. A buffer system is a solution that resists a change in pH when acids or bases are added. The skin possesses a fairly high buffer capacity, which is determined by the amount of H+ or OH- ions that is needed until the pH value of a solution changes by the unit 1. Buffers contain a weak or medium strong acid (base) and the corresponding salt. Buffers that show a pKa in the range of the Stratum corneum surface pH are most important for the skin. Buffer capacity is reduced both in baby skin and in aged skin. External factors, water, and detergent may reduce the local buffer capacity because of the elution of buffer chemicals leading to increased pH and irritative contact dermatitis. Inflammatory diseases, including atopic dermatitis, psoriasis, and acne vulgaris, which show an increased pH should probably also have reduced buffer capacities. For the treatment of the skin diseases and in aged skin, emollient with a pH that is slightly more acidic than the average normal pH and an appropriate buffer capacity should be preferably used.

Skin Care Products for Healthy and Diseased Skin

The industry offers a vast armamentarium of skin care products (SCP) to cleanse the skin; to reduce/eliminate unpleasant skin symptoms; to restore, reinforce, fortify and protect undamaged, vulnerable or damaged skin; and to provide a pleasant skin and body feel. Skin care products are readily available and their promotions with a variety of tall claims are omnipresent. This text discusses the various interpretations of skin care, the diversity of its comprehensions and the various groups of receivers and their needs for skin care. Skin care is part of our daily routines, the information on the effects of SCP is omnipresent and the purchase of SCP seems straightforward. However, the true essence of SCP remains concealed to many. This is mainly due to that fact that the "physico-chemical anatomy," the nomenclature and the regulatory classification of SCP as well as the role and the significance of active and inactive ingredients within these products are not well understood. This text addresses the different views, interpretations and comprehensions. The final part highlights the current challenges with SCP and gives an outlook on how to improve our mutual understanding of SCP.

Measurement of Skin Surface pH

The acidic nature of the skin surface was recognised more than a century ago and has been measured since 1928. Several non-invasive methods for measuring skin surface pH have been developed ever since and have contributed to our understanding of healthy and diseased skin. This chapter summarises the endogenous physiological, exogenous and environmental factors that influence skin surface pH and its measurement as well as the different measurement methods for skin surface pH, with specific emphasis on the classic planar glass electrode method. Also, practical guidance for measurement of skin surface pH using the planar glass electrode method is provided. Adherence to practical skin surface pH measurement (method) guidelines with due consideration and practicable control of all factors that may affect skin surface pH will ensure credible pH measurement results in our continuous pursuit of understanding especially diseased skin.

The Acid Mantle: A Myth or an Essential Part of Skin Health?

Ninety years ago - in 1928, the term acid mantle was coined by the physicians Heinrich Schade and Alfred Marchionini in Kiel, Germany. A decade later Marchionini and several coworkers published 5 scientific communications in the Klinische Wochenschrift on "Der Säuremantel der Haut und Bakterienabwehr" (acid mantle and defense against bacteria). They described experimental detail, documented age- and body site as well as skin disease-dependent skin pH shifts, and discussed the significance of the pH and bacterial growth on the skin. In their fourth and fifth communication, they made the first connection between the altered quantitative and qualitative bacterial growth in pathologically modified skin and the shifted skin pH and attributed it partly to the gap in the acid mantle (pathologische Lücke des Säuremantels). They also investigated the pH of several topical dermatologic preparations and concluded that their benefit can at least partly be attributed to their acid character and recommended the systematic investigation of acid treatments in dermatology. At that time, the physiologic role of the acid skin surface was thought to be a protective mechanism against invading organisms. Hence, it seemed reasonable to allocate protection to an easy and conceivable term such as "mantle." Today, "acid mantle" as a term is still a very suitable metaphor to illustrate the protective quality of the "acid" in the skin and the term has become part of colloquial speech. In the meantime, our understanding of the skin pH has broadened, and we know that the acid character and its gradual change within the skin also help to orchestrate epidermal differentiation and corneocyte shedding. For many more biochemical processes within the skin, the compartmental pH is crucial, for example, in pigmentation, ion homeostasis, epidermal (stem) cell behavior, and so on. The often existing difference between the H+ concentration of extra- and intracellular as well as subcellular compartments establishes an ionic, electric, and/or osmotic driving force; hence, H+ concentration per se acts as an extra-, intra,- and subcellular signaling modality affecting and controlling many cellular functions. One may even consider pH a universal signal and effector. It is therefore also no surprise that skin pH shifts have been observed in various skin pathologies. More recently, in carefully controlled trials (acne, atopic dermatitis, incontinence-associated dermatitis, aged skin), the benefits of targeted skin acidification have become evident and the use of topical preparations with reduced pH may be recommended. The currently prevailing formulation concepts for direct acidification are based on a reduced pH of the hydrophilic product phase in combination with a buffer with a sufficiently high buffering capacity within the vehicle.

Characterization of Panton-Valentine leukocidin-positive Staphylococcus aureus from skin and soft tissue infections and wounds in Nigeria: a cross-sectional study

Background:Staphylococcus aureus is a significant pathogen implicated in numerous nosocomial and community-acquired infections. The Panton-Valentine leukocidin (PVL) can be associated with severe necrotizing diseases such as pneumonia, skin and soft tissue infection (SSTI).  Methods: In total, 96 S. aureus isolates were obtained from patients presenting with wounds (n=48) and soft tissue infections (SSTIs, n=48). These were characterized based on their antimicrobial susceptibility profile, the possession of virulence genes (e.g. capsular type, PVL), accessory gene regulator ( agr) type, and the staphylococcal protein A ( spa) type. The production of the PVL protein was assessed by western blotting. Results: All isolates were susceptible to methicillin. The resistance was highest to penicillin (97.9%), followed by trimethoprim/sulfamethoxazole (85.4%) and tetracycline (10.4%). The PVL gene was found in 83.3% of isolates from SSTIs and in 79.2% of isolates from wound. Of these, 53 (68%) produced PVL as assessed by western blotting. The most prevalent spa type was the t084 (78.1%, n=75) and, majority of the isolates carried  agr2 (82.3%, n=79). Conclusions: Prevalence of antibiotic resistant PVL-positive methicillin susceptible S. aureus strains has severe implications on PVL mediated infections.

Randomised, double-blind, placebo-controlled trial of IL1-trap, rilonacept, in systemic sclerosis. A phase I/II biomarker trial

OBJECTIVES

This clinical trial was designed to study the safety and efficacy of blocking IL-1 in skin fibrosis of patients with diffuse cutaneous systemic sclerosis (dcSSc), and to test the hypothesis that inhibition of IL-1 by rilonacept will downregulate expression of the 2G SSc gene biomarker as a surrogate for the modified Rodnan skin score (MRSS).

METHODS

19 dcSSc patients were randomised 2:1 active treatment:placebo in this double blinded trial. Study patients received weekly treatments with either subcutaneous rilanocept 320 mg loading dose at day 0 and then 160 mg for each of the 5 subsequent weekly doses, or placebo. Skin biopsies were taken to test 2G SSc biomarker gene expression at day 0 before treatment and one week after the final study drug dose, comparing gene expression changes between rilonacept- and placebo-treated patients, as well as the change in gene expression at week 6 compared to baseline in rilonacept-treated patients. Safety assessments extended to 6 weeks after the final dose of study drug or placebo. Other secondary outcome measures included global and IL-1-regulated gene expression, serum biomarkers and the MRSS.

RESULTS

Rilonacept compared to placebo-treated patients did not show any treatment-related effect on the 2G SSc biomarker. Rilonacept treatment also failed to alter IL-6 expression in skin, serum IL-6, C-reactive protein, or CCL18, a marker of IL-6 activity in SSc.

CONCLUSIONS

In this small trial we did not observe any effect of blocking IL-1 on clinical skin disease or biomarkers of IL-1 activity.

Collagenase nanocapsules: An approach to fibrosis treatment

Fibrosis is a common lesion in different pathologic diseases and defined by the excessive accumulation of collagen. Different approaches have been used to treat different conditions characterized by fibrosis. The FDA and EMA approved the use of collagenase to treat palmar fibromatosis (Dupuytren's contracture). The EMA approved additionally its use in severe Peyronie's disease, but it has been used off label in other conditions [1,2]. The approved treatment includes up to three (in palmar fibromatosis) or up to eight (in penile fibromatosis) injections followed by finger extension or penile modeling procedures, typically causing severe pain. Frequent single injections are adequate to treat palmar fibromatosis [3]. The need to repeatedly inject doses of this enzyme can be due to the labile nature of collagenase, which exhibits a complete activity loss after a short period of time. This study presents a novel strategy to manage this enzyme based on the synthesis of polymeric nanocapsules that contain collagenase encapsulated within their matrix. These nanocapsules have been engineered for achieving a gradual release of the encapsulated enzyme for a longer time, which can be up to ten days. The efficacy of these nanocapsules has been tested in a murine model of local dermal fibrosis, and the results demonstrate a reduction in fibrosis greater than that with the injection of free enzyme; this type of treatment showed a significant improvement compared to conventional therapy of free collagenase.

STATEMENT OF SIGNIFICANCE

The use of proteins as therapeutic molecules has recently attracted great interest. Collagenase injection is the current treatment for fibrotic diseases. Unfortunately, proteins have a low stability and presume several repetition cycles to obtain an effective treatment. This article describes a novel treatment for these types of diseases using collagenase nanocapsules designed to exhibit a sustainable release of the encapsulated enzyme, which maintains the enzymatic activity for a long period of time. The therapeutic effect of nanocapsules was tested in a murine mouse model of local dermal fibrosis, and the results showed an important improved effect compared to the effect of the administration of free enzyme. These results indicate a high potential for this novel system to improve the current treatment for fibrotic diseases.

Immune response patterns in non-communicable inflammatory skin diseases

Non-communicable inflammatory skin diseases (ncISD) such as psoriasis or atopic eczema are a major cause of global disease burden. Due to their impact and complexity, ncISD represent a major challenge of modern medicine. Dermatology textbooks describe more than 100 different ncISD based on clinical phenotype and histological architecture. In the last decades, this historical description was complemented by increasing molecular knowledge - and this knowledge is now being translated into specific therapeutics. Combining the enormous advances made in lymphocyte immunology and molecular genetics with clinical and histological phenotyping reveals six immune response patterns of the skin - type I immune cells cause the lichenoid pattern characterized by immune-mediated cell death of keratinocytes; type II immune cells underlie the eczematous pattern with impaired epidermal barrier, infection and eosinophils as well as the bullous pattern with loss of epithelial integrity; Th17 cells and ILC3 mediate the psoriatic pattern characterized by acanthosis, high metabolic activity and neutrophils; dysbalance of regulatory T cells causes either the fibrogenic pattern with rarefication of cells and dermal thickening or the granulomatous pattern defined by formation of granulomas. With more and more specific therapeutic agents approved, classifying ncISD also according to their immune response pattern will become highly relevant. This review defines the six immune response patterns of ncISD and highlights therapeutic strategies targeting key lymphocyte mediators.

p53 Protein Expression and Cell Proliferation in Non-Neoplastic and Neoplastic Proliferative Skin Diseases

Aims and background

The p53 protein is essential for the regulation of cell proliferation and its aberrant accumulation is usually seen in malignant tumors but also occurs in squamous epithelium of inflammatory skin diseases characterized by hyperproliferation. The aim of this study is to elucidate the role of the p53 tumor suppressor protein in the pathogenesis of different hyperproliferative, non-malignant and malignant skin diseases, and to determine the association between p53 overexpression and cell proliferation. We also investigated the influence of aging on p53 and Ki-67 protein expression.

Methods

One hundred and fifty skin specimens divided into 30 samples each of normal skin (NS), psoriatic skin (PS), keratoacanthomas (KA), basal cell carcinomas (BCC), and squamous cell carcinomas (SCC) were examined immunohistochemically to assess p53 and Ki-67 protein expression.

Results

p53 immunostaining of NS, PS, KA, BCC and SCC was detected in 39.0%, 46.7%, 66.7%, 80% and 86.7% of cases, respectively. Median values and ranges of p53 protein expression were as follows: 0.0% (range, 0.0–1.8%) in NS, 0.0% (range, 0.0–6.5%) in PS, 9.2% (range, 0.0–24.0%) in KA, 19.3% (range, 0.0–48.1%) in BCC and 30.1% (range, 0.0–68.1%) in SCC. p53- and Ki-67-positive cells were present in basal (NS) and suprabasal layers (PS), and not only in cancer nests of KA, BCC and SCC but also in dysplastic and even morphologically normal epidermis adjoining cancers. The positivity of p53 and Ki-67 proteins differed significantly among the groups, with no differences in p53 expression between NS and PS and in Ki-67 expression between PS and KA. Within all groups there was a significant correlation between p53 and Ki-67 expression. Lesion location and patient age, with the exception of location in PS and age in BCC, were significantly related to p53 and Ki-67 expression in all groups.

Conclusions

Our findings suggest that p53 overexpression occurs mainly in neoplastic skin lesions, although it may also occur in squamous epithelium of inflammatory skin diseases such as PS, as well as in normal skin epithelium. It is associated with cell proliferation in normal as well as altered epithelium. p53 protein overexpression is an age-related process and significantly associated with sun exposure, especially in NS and PS but also in KA and SCC. Our findings suggest that Ki-67 rate and p53 protein expression reflect the degree of malignancy in the examined cutaneous neoplasms.

A critical role for donor-derived IL-22 in cutaneous chronic GVHD

Graft-versus-host disease (GVHD) is the major cause of nonrelapse morbidity and mortality after allogeneic stem cell transplantation (allo-SCT). Prevention and treatment of GVHD remain inadequate and commonly lead to end-organ dysfunction and opportunistic infection. The role of interleukin (IL)-17 and IL-22 in GVHD remains uncertain, due to an apparent lack of lineage fidelity and variable and contextually determined protective and pathogenic effects. We demonstrate that donor T cell-derived IL-22 significantly exacerbates cutaneous chronic GVHD and that IL-22 is produced by highly inflammatory donor CD4+ T cells posttransplantation. IL-22 and IL-17A derive from both independent and overlapping lineages, defined as T helper (Th)22 and IL-22+ Th17 cells. Donor Th22 and IL-22+ Th17 cells share a similar IL-6-dependent developmental pathway, and while Th22 cells arise independently of the IL-22+ Th17 lineage, IL-17 signaling to donor Th22 directly promotes their development in allo-SCT. Importantly, while both IL-22 and IL-17 mediate skin GVHD, Th17-induced chronic GVHD can be attenuated by IL-22 inhibition in preclinical systems. In the clinic, high levels of both IL-17A and IL-22 expression are present in the skin of patients with GVHD after allo-SCT. Together, these data demonstrate a key role for donor-derived IL-22 in patients with chronic skin GVHD and confirm parallel but symbiotic developmental pathways of Th22 and Th17 differentiation.

β-Catenin and CD44 Expression in Keratoacanthoma and Squamous Cell Carcinoma of the Skin

CD44 and β-catenin are adhesion molecules expressed on a wide variety of cells. Failure of this expression is believed to lead to disruption of cell-cell adhesion and to neoplasia. The aim of this study was to investigate the staining intensity of CD44 and β-catenin in keratoacanthomas and squamous cell carcinomas of the skin. The proliferation index, PCNA staining, was also evaluated in these cases. The abnormal expression of β-catenin significantly predominated in squamous cell carcinomas (n = 20, 76.9%) compared with keratoacanthomas (P = 0.002, χ2 = 7.8). Most keratoacanthomas (n = 11, 61.1%) more frequently showed strong staining intensity with CD44 compared with squamous cell carcinoma (P = 0.001, χ2 = 13.7). The proliferation index was higher in squamous cell carcinoma (P = 0.000, χ2 = 12.8). These findings suggest that CD44 and β-catenin expression may have an important role in the development of malignancy and in the determination of biological features of keratoacanthoma and squamous cell carcinoma of the skin.

Abnormal Sphingolipid World in Inflammation Specific for Lysosomal Storage Diseases and Skin Disorders

Research in recent years has shown that sphingolipids are essential signalling molecules for the proper biological and structural functioning of cells. Long-term studies on the metabolism of sphingolipids have provided evidence for their role in the pathogenesis of a number of diseases. As many inflammatory diseases, such as lysosomal storage disorders and some dermatologic diseases, including psoriasis, atopic dermatitis and ichthyoses, are associated with the altered composition and metabolism of sphingolipids, more studies precisely determining the responsibilities of these compounds for disease states are required to develop novel pharmacological treatment opportunities. It is worth emphasizing that knowledge from the study of inflammatory metabolic diseases and especially the possibility of their treatment may lead to insight into related metabolic pathways, including those involved in the formation of the epidermal barrier and providing new approaches towards workable therapies.

Percutaneous Sensitization to Soybean Proteins Is Attenuated by Oral Tolerance

Oral tolerance prevents allergic responses, but cutaneous exposure to food allergens predisposes individuals to food allergies. Soybean, a major allergenic food, is also an ingredient in various cosmetic products. However, it remains to be determined whether oral tolerance prevents percutaneous sensitization to soybean proteins in humans or animal models. In this study, BALB/c mice were divided into three groups; the SS group fed a soybean-containing diet, and the CS and control (C) groups fed a soybean-free diet. After being dorsally shaved, the CS and SS groups were epicutaneously exposed to a soybean extract while the control group was exposed to only the carrier. Specific IgE and IgG1 immunoglobulins secreted in response to the soybean proteins were measured using enzyme-linked immunosorbent assays. Exposure to the soybean extract elicited the secretion of IgE and IgG1 specific for Gly m 5 and Gly m 6, and trypsin inhibitor. Oral soybean consumption attenuated the secretion of all the soybean-specific IgEs and IgG1s, suggesting that percutaneous sensitization to soybean proteins is attenuated by oral tolerance.

Antifungal and antioxidant activities of Coleonema album and C. pulchellum against skin diseases

CONTEXT

Coleonema album (Thunb) Bart. & H. L. Wendl (Rutaceae) has been used in the formulation of skincare products, and the Khoisan people rub it on their skin to add luster. Coleonema pulchellum I. Williams has received less attention in the South African traditional medicine.

OBJECTIVE

This study investigates the antifungal and antioxidant activities of C. album and C. pulchellum essential oil (EO) and leaf extracts; and analyzes the chemical components of their EOs.

MATERIALS AND METHODS

Antifungal activity of leaf extracts was determined using the microdilution method with griseofulvin and ketoconazole as controls. Antifungal capacity of EO was investigated using the 'Volatile release plate method'. Trichophyton rubrum (ATCC 28188) and T. mentagrophytes (ATCC 9533) mycelia (0.3 cm diameter) were placed on fresh yeast malt agar in Petri dishes with filter paper (impregnated with 20 μL of EO) on the lid for direct exposure to EO volatiles while plates without EO were used as controls. The incubation time was seven days. Antioxidant activities of the leaf extracts were determined.

RESULTS

Methanol leaf extract of C. pulchellum inhibited the growth of three fungi tested with MIC values of 195, 391 and 49 μg/mL for Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum gypseum, respectively. Terpenes formed the major components of the EO. The EO from both plants inhibited the growth of T. rubrum in vitro.

DISCUSSION AND CONCLUSION

This study revealed the therapeutic value of C. pulchellum. Coleonema album and C. pulchellum should be considered as potential plants for skin ointment from natural origin.

Mineral Depositions of Calcifying Skin Disorders are Predominantly Composed of Carbonate Apatite

Subcutaneous calcifications can lead to complications, including pain, inflammation, ulceration and immobilization. Studies on the pathophysiology of mineral compositions and effective treatment modalities are limited. We therefore studied 14 patients with subcutaneous calcifications. Mineral material was collected and analysed by Fourier transform infrared spectrometry. Blood analyses were run to evaluate systemic alterations of mineral metabolism. Carbonate apatite (CAP) was found to be the single constituent in the majority of patients (n = 9, 64.3%), 3 cases (21.4%) had a composition of CAP and calcium oxalate dihydrate and one case had a combination of CAP and magnesium ammonium phosphate, whereas CAP was the major component in all 4 cases. Only one case showed predominantly calcium oxalate. Thus, CAP was found to be the only or predominant component in most cases of subcutaneous calcifications. Chemical analyses of the mineral compositions may aid in the development of new treatment regimes to improve the solubility of mineral components and to decrease extraosseous calcifications.

Recovery Effects of Oral Administration of Glucosylceramide and Beet Extract on Skin Barrier Destruction by UVB in Hairless Mice

Purified glucosylceramide from beet extract (beet GlcCer) and beet extract containing an equal amount of GlcCer were administered orally to ultra violet B (UVB)-irradiated mice, and differences in the protective effects against skin barrier dysfunction caused by UVB irradiation were compared. In the beet GlcCer group, epidermal thickening and the decrease in stratum corneum (SC) ceramide content caused by UVB irradiation were reduced. In the group that was orally administered beet extract containing glucosylceramide, effects similar to those in the beet GlcCer group were observed. Oral administration of beet GlcCer had no obvious effects against an increase in TEWL or decrease in SC water content after UVB irradiation, but there was improvement in the beet extract group. Oral administration of beet GlcCer is effective in improving skin barrier function in UVB-irradiated mice. Beet extract contains constituents other than GlcCer that are also effective in improving skin barrier function.

Progress and Future Prospectives in Skin-on-Chip Development with Emphasis on the use of Different Cell Types and Technical Challenges

Understanding the healthy and diseased state of skin is important in many areas of basic and applied research. Although the field of skin tissue engineering has advanced greatly over the last years, current in vitro skin models still do not mimic the complexity of the human skin. Skin-on-chip and induced pluripotent stem cells (iPSC) might be key technologies to improve in vitro skin models. This review summarizes the state of the art of in vitro skin models with regard to cell sources (primary, cell line, iPSC) and microfluidic devices. It can be concluded that iPSC have the potential to be differentiated into many kinds of immunologically matched cells and skin-on-chip technology might lead to more physiologically relevant skin models due to the controlled environment, possible exchange of immune cells, and an increased barrier function. Therefore the combination of iPSC and skin-on-chip is expected to lead to superior healthy and diseased in vitro skin models.

Development of hypomelanotic macules is associated with constitutive activated mTORC1 in tuberous sclerosis complex

TSC1 and TSC2 are genes mutated in the syndrome TSC (tuberous sclerosis complex). We describe a 3-generation family with 17 affected members, all presenting classic TSC features except renal manifestations. The disease segregates with a silent substitution in TSC2, c.4149C>T, p.(Ser1383Ser), which leads to the formation of an active donor splice site, resulting in three shorter alternatively spliced transcripts with premature stop codons. However a small amount of normal spliced transcript is apparently produced from the mutated allele, which might explain the milder phenotype. The gene products of TSC1/2 form a complex which at energy limiting states, down-regulates the activity of the regulator of protein synthesis, the mammalian target of rapamycin complex1 (mTORC1). As expected, in contrast to cultured control fibroblasts, starvation of cultured patient fibroblasts obtained from a hypomelanotic macule did not lead to repression of mTORC1, whereas partial repression was observed in patient fibroblasts obtained from non-lesional skin. The findings indicate that the development of hypomelanotic macules is associated with constitutive activated mTORC1, whereas mild deregulation of mTORC1 allows the maintenance of normal skin. Furthermore, the finding establishes the pathogenic effect of the "silent" c.4149C>T substitution and emphasizes the need for awareness when interpreting silent substitutions in general.

Ultraviolet Photobiology in Dermatology

The effects of ultraviolet radiation on human skin have been studied for years, and both its harmful and therapeutic effects are well known. Exposure to UV light can lead to sunburn, immunosuppression, skin aging, and carcinogenesis, and photoprotection is strongly advocated. However, when used under controlled conditions, UV radiation can also be helpful in the diagnosis and treatment of many skin conditions.

Spotlight on the Use of Nitric Oxide in Dermatology: What Is It? What Does It Do? Can It Become an Important Addition to the Therapeutic Armamentarium for Skin Disease?

Nitric oxide (NO) is a diatomic gas that is synthesized within and released by multiple host cell types functioning to provide a variety of physiologic and homeostatic effects. Nitric oxide exhibits a variety of effects that relate significantly with outcomes that can provide therapeutic benefit if properly formulated and released. These include anti-inflammatory, immunomodulatory, antimicrobial, vasodilatory properties, and effects that are beneficial to wound healing. Lack of antibiotic resistance appears to be one major advantage of topically delivered NO. A specific topical formulation of NO has been developed that has been shown thus far in clinical studies to exhibit favorable efficacy and safety. This article provides a thorough review of the biologic effects of NO, discusses modes of action and potential pharmacologic benefits, and reviews currently available clinical data for acne. J Drugs Dermatol. 2017;16(1 Suppl 1):s4-10.

Evaluation of wound healing property of Caesalpinia mimosoides Lam

ETHNOPHARMACOLOGICAL RELEVANCE

Caesalpinia mimosoides Lam. is one of the important traditional folk medicinal plants in the treatment of skin diseases and wounds used by healers of Uttara Kannada district of Karnataka state (India). However scientific validation of documented traditional knowledge related to medicinal plants is an important path in current scenario to fulfill the increasing demand of herbal medicine.

AIM OF THE STUDY

The study was carried out to evaluate the claimed uses of Caesalpinia mimosoides using antimicrobial, wound healing and antioxidant activities followed by detection of possible active bio-constituents.

MATERIALS AND METHODS

Extracts prepared by hot percolation method were subjected to preliminary phytochemical analysis followed by antimicrobial activity using MIC assay. In vivo wound healing activity was evaluated by circular excision and linear incision wound models. The extract with significant antimicrobial and wound healing activity was investigated for antioxidant capacity using DPPH, nitric oxide, antilipid peroxidation and total antioxidant activity methods. Total phenolic and flavonoid contents were also determined by Folin-Ciocalteu, Swain and Hillis methods. Possible bio-active constituents were identified by GC-MS technique. RP-UFLC-DAD analysis was carried out to quantify ethyl gallate and gallic acid in the plant extract.

RESULTS

Preliminary phytochemical analysis showed positive results for ethanol and aqueous extracts for all the chemical constituents. The ethanol extract proved potent antimicrobial activity against both bacterial and fungal skin pathogens compared to other extracts. The efficacy of topical application of potent ethanol extract and traditionally used aqueous extracts was evidenced by the complete re-epithelization of the epidermal layer with increased percentage of wound contraction in a shorter period. However, aqueous extract failed to perform a consistent effect in the histopathological assessment. Ethanol extract showed effective scavenging activity against DPPH and nitric oxide free radicals with an expressive amount of phenolic and moderate concentration of flavonoid contents. Ethyl gallate and gallic acid were found to be the probable bio-active compounds evidenced by GCMS and RP-UFLC-DAD analysis.

CONCLUSION

The study revealed the significant antimicrobial, wound healing and antioxidant activities of tender parts of C. mimosoides and proved the traditional folklore knowledge.

Differential Expression of Hedgehog and Snail in Cutaneous Fibrosing Disorders: Implications for Targeted Inhibition

OBJECTIVES

To examine Hedgehog signaling in cutaneous fibrosing disorders for which effective approved therapies are lacking, expand our knowledge of pathophysiology, and explore the rationale for targeted inhibition.

METHODS

Stain intensity and percentage of cells staining for Sonic hedgehog (Shh), Indian hedgehog (Ihh), Patched (Ptch), glycogen synthase kinase 3 β (GSK3-β), β-catenin, and Snail were evaluated in human skin biopsy specimens of keloid, hypertrophic scar (Hscar), scleroderma, nephrogenic systemic fibrosis (NSF), scar, and normal skin using a tissue microarray.

RESULTS

Ihh, but not Shh, was detected in a significantly larger proportion of cells for all case types. Ptch, GSK3-β, and β-catenin showed a gradient of expression: highest in NSF and keloid; moderate in normal skin, scar, and Hscar; and lowest in scleroderma. Snail expression was binary: low in normal skin but high in all fibrosing conditions studied.

CONCLUSIONS

Differential overexpression of Hedgehog and Snail in cutaneous fibrosing disorders demonstrates a role for targeted inhibition. Ptch, GSK3-β, and β-catenin can help differentiate scleroderma from NSF in histologically subtle cases. Differences in expression between keloid and hypertrophic scar support the concept that they are pathophysiologically distinct disorders. Our findings implicate Snail as a target for the prevention of fibrogenesis or fibrosis progression and may offer a means to assess response to therapy.

TH9 cells in skin disorders

Interleukin 9 secreting T_H9 cells have been proposed as the latest addition to the family of T helper cell subsets. While a growing body of evidence from animal models points to important roles for these cells in allergic inflammation of the lung, autoinflammation of the gastrointestinal tract, and tumor immunity, their role in skin immunity and skin immunopathology remains poorly defined. Interestingly, studies of T helper cells from healthy humans suggest that T_H9 cells are predominantly skin-homing and skin-resident and that they are involved in protection against extracellular pathogens. Thus, T_H9 cells have entered the stage as potential mediators of cutaneous pathology. However, under which conditions and by which mechanisms these cells contribute to skin immunity and disease still has to be investigated. Here, we review our current understanding of T_H9 cells as skin-tropic T helper cells and their involvement in skin pathology. Further, we discuss open questions with regard to the intricate nature of interleukin 9 producing T helper cells.