Neuropathic pain caused by miswiring and abnormal end organ targeting.

Nerve injury leads to chronic pain and exaggerated sensitivity to gentle touch (allodynia) as well as a loss of sensation in the areas in which injured and non-injured nerves come together1-3. The mechanisms that disambiguate these mixed and paradoxical symptoms are unknown. Here we longitudinally and non-invasively imaged genetically labelled populations of fibres that sense noxious stimuli (nociceptors) and gentle touch (low-threshold afferents) peripherally in the skin for longer than 10 months after nerve injury, while simultaneously tracking pain-related behaviour in the same mice. Fully denervated areas of skin initially lost sensation, gradually recovered normal sensitivity and developed marked allodynia and aversion to gentle touch several months after injury. This reinnervation-induced neuropathic pain involved nociceptors that sprouted into denervated territories precisely reproducing the initial pattern of innervation, were guided by blood vessels and showed irregular terminal connectivity in the skin and lowered activation thresholds mimicking low-threshold afferents. By contrast, low-threshold afferents-which normally mediate touch sensation as well as allodynia in intact nerve territories after injury4-7-did not reinnervate, leading to an aberrant innervation of tactile end organs such as Meissner corpuscles with nociceptors alone. Genetic ablation of nociceptors fully abrogated reinnervation allodynia. Our results thus reveal the emergence of a form of chronic neuropathic pain that is driven by structural plasticity, abnormal terminal connectivity and malfunction of nociceptors during reinnervation, and provide a mechanistic framework for the paradoxical sensory manifestations that are observed clinically and can impose a heavy burden on patients.

Oral 11ß-HSD1 inhibitor AZD4017 improves wound healing and skin integrity in adults with type 2 diabetes mellitus: a pilot randomized controlled trial.

BACKGROUND: Chronic wounds (e.g. diabetic foot ulcers) reduce the quality of life, yet treatments remain limited. Glucocorticoids (activated by the enzyme 11ß-hydroxysteroid dehydrogenase type 1, 11ß-HSD1) impair wound healing. OBJECTIVES: Efficacy, safety, and feasibility of 11ß-HSD1 inhibition for skin function and wound healing. DESIGN: Investigator-initiated, double-blind, randomized, placebo-controlled, parallel-group phase 2b pilot trial. METHODS: Single-center secondary care setting. Adults with type 2 diabetes mellitus without foot ulcers were administered 400 mg oral 11ß-HSD1 inhibitor AZD4017 (n = 14) or placebo (n = 14) bi-daily for 35 days. Participants underwent 3-mm full-thickness punch skin biopsies at baseline and on day 28; wound healing was monitored after 2 and 7 days. Computer-generated 1:1 randomization was pharmacy-administered. Analysis was descriptive and focused on CI estimation. Of the 36 participants screened, 28 were randomized. RESULTS: Exploratory proof-of-concept efficacy analysis suggested AZD4017 did not inhibit 24-h ex vivoskin 11ß-HSD1 activity (primary outcome; difference in percentage conversion per 24 h 1.1% (90% CI: -3.4 to 5.5) but reduced systemic 11ß-HSD1 activity by 87% (69-104%). Wound diameter was 34% (7-63%) smaller with AZD4017 at day 2, and 48% (12-85%) smaller after repeat wounding at day 30. AZD4017 improved epidermal integrity but modestly impaired barrier function. Minimal adverse events were comparable to placebo. Recruitment rate, retention, and data completeness were 2.9/month, 27/28, and 95.3%, respectively. CONCLUSION: A phase 2 trial is feasible, and preliminary proof-of-concept data suggests AZD4017 warrants further investigation in conditions of delayed healing, for example in diabetic foot ulcers. SIGNIFICANCE STATEMENT: Stress hormone activation by the enzyme 11ß-HSD type 1 impairs skin function (e.g. integrity) and delays wound healing in animal models of diabetes, but effects in human skin were previously unknown. Skin function was evaluated in response to treatment with a 11ß-HSD type 1 inhibitor (AZD4017), or placebo, in people with type 2 diabetes. Importantly, AZD4017 was safe and well tolerated. This first-in-human randomized, controlled, clinical trial found novel evidence that 11ß-HSD type 1 regulates skin function in humans, including improved wound healing, epidermal integrity, and increased water loss. Results warrant further studies in conditions of impaired wound healing, for example, diabetic foot ulcers to evaluate 11ß-HSD type 1 as a novel therapeutic target forchronic wounds.

The effects of the pressure on the coccygeal skin on the perception of backward-leaning sitting positions in stroke patients.

The present study investigated the effects of an additional pressure stimulus on coccygeal skin using an original tool to evaluate the perceptibility of sitting while leaning backward in 13 chronic stroke patients who were able to walk independently and 12 age-matched healthy subjects. Each participant's perception of the trunk reference angle at which they felt the highest-pressure stimulation of the coccygeal skin while leaning backward from a quiet sitting position was evaluated based on the accuracy of each reproduction under both normal and additional pressure conditions. The absolute error under the pressure condition was significantly smaller than that under the normal condition in the control group, while no marked difference between conditions was found in the stroke group. The relationship between the absolute error under the normal condition and the pressure effect index showed a significant negative correlation in the stroke group. In stroke patients with a high trunk position perceptibility under the normal condition, the additional pressure information may have functioned as a disturbance and reduced the position perceptibility. In contrast, stroke patients with a low perceptibility in the normal condition may have been able to re-weight and prioritize the additional pressure information in the reference frame. In the control group, the added pressure information may have been re-weighted as prior position information in the reference frame.

Sterilized human skin graft with a dose of 25 kGy provides a privileged immune and collagen microenvironment in the adhesion of Nude mice wounds.

This study aimed to report the effects of different doses of ionizing radiation on inflammatory and repair stage of human skin graft adherence in Nude mice wounds. Animals were divided into transplanted with irradiated human skin grafts (IHSG) at 25 and 50 kGy (IHSG 25 kGy; IHSG 50 kGy) and non-IHSG and euthanized on the 3rd, 7th and 21st days after the surgery, by gross and microscopic changes, immunostaining for human type I collagen (Col I) and mouse Col I and Col III and inflammatory cells. We found an effectiveness of human split-thickness graft adherence in mice transplanted with IHSG 25 kGy, as well decrease in dermo-epidermal necrosis and neutrophils, lower loss of skin thickness, epithelization and neo-vascularization. Day 21 post-transplantation with IHSG 25 kGy was observed a well-preserved human skin in the border of the graft, a prominent granulation tissue in an organization by proliferated fibroblasts, Col III deposition and increased B-cells and macrophages. A complete adherence of human skin graft occurred with IHSG 25 kGy. We suggest that the ionizing radiation at 25 kGy mediates inflammation and the repair stage of human skin graft adherence in murine model, thus emerging as a potential tool in healing cutaneous wounds.

Plant-Derived Antioxidants: Significance in Skin Health and the Ageing Process.

Natural substances have traditionally been used in skin care for centuries. There is now an ongoing search for new natural bioactives that not only promote skin health but also protect the skin against various harmful factors, including ultraviolet radiation and free radicals. Free radicals, by disrupting defence and restoration mechanisms, significantly contribute to skin damage and accelerate ageing. Natural compounds present in plants exhibit antioxidant properties and the ability to scavenge free radicals. The increased interest in plant chemistry is linked to the growing interest in plant materials as natural antioxidants. This review focuses on aromatic and medicinal plants as a source of antioxidant substances, such as polyphenols, tocopherols, carotenoids, ascorbic acid, and macromolecules (including polysaccharides and peptides) as well as components of essential oils, and their role in skin health and the ageing process.

Psoriasis and uveitis.

PURPOSE: Psoriasis, which is a chronic, immune-mediated skin disease of unknown etiology, not only affects the skin, but also is linked to many systemic conditions such as arthritis, cardiovascular disease, depression, and malignancy. Although many types of eye involvement are encountered in psoriasis patients, dry eye is the first among them. Uveitis is an entity that can be associated with psoriasis and can cause severe vision loss as a result of late diagnosis, inadequate and inappropriate treatment. In this review, we aimed to shed light on the diagnosis, type, prognosis and treatment of uveitis in psoriasis patients by compiling current datas obtained from published studies and to guide the follow-up and treatment of these patients. METHODS: A systematic literature search was done on PubMed using key words including "psoriasis", "psoriatic arthritis", "uveitis", "TNF- inhibitors", "HLA B27". RESULTS: In the literature, the frequency, type and treatment of uveitis developing in the course of psoriatic arthritis are clearly defined. However, the coexistence of psoriasis and uveitis has not yet been clarified due to few numbers published studies and designs of these studies. Since we examined the existing studies, we determined that the coexistence of psoriasis and uveitis could be acute or insidious, and the probability and severity of uveitis increased as the severity of skin and joint involvement increased. In addition, we found that psoriasis-associated uveitis can be bilateral, chronic, severe progression and with a high recurrence rate. CONCLUSION: The relations between non-arthritic psoriasis and uveitis have not yet been fully elucidated. Physicians who treat these diseases must be cautious, and refer their patients who have psoriasis to an ophthalmologist for periodic examination, even if they do not have eye symptoms. On the other hand, ophthalmologists must be careful in uveitis patients in terms of skin and joint involvement, and must not overlook the underlying disease.

Therapeutic downregulation of neuronal PAS domain 2 (Npas2) promotes surgical skin wound healing.

Attempts to minimize scarring remain among the most difficult challenges facing surgeons, despite the use of optimal wound closure techniques. Previously, we reported improved healing of dermal excisional wounds in circadian clock neuronal PAS domain 2 (Npas2)-null mice. In this study, we performed high-throughput drug screening to identify a compound that downregulates Npas2 activity. The hit compound (Dwn1) suppressed circadian Npas2 expression, increased murine dermal fibroblast cell migration, and decreased collagen synthesis in vitro. Based on the in vitro results, Dwn1 was topically applied to iatrogenic full-thickness dorsal cutaneous wounds in a murine model. The Dwn1-treated dermal wounds healed faster with favorable mechanical strength and developed less granulation tissue than the controls. The expression of type I collagen, Tgfß1, and α-smooth muscle actin was significantly decreased in Dwn1-treated wounds, suggesting that hypertrophic scarring and myofibroblast differentiation are attenuated by Dwn1 treatment. NPAS2 may represent an important target for therapeutic approaches to optimal surgical wound management.

Innovation in the treatment of atopic dermatitis: Emerging topical and oral Janus kinase inhibitors.

Atopic dermatitis (AD) is characterized by chronic, eczematous, severe pruritic skin lesions. The knowledge on the pathogenesis of AD is driving the development of new drugs. From the research results, it has been revealed that Th2 cell-mediated immunity, skin barrier dysfunction, and pruritus cause a vicious cycle of AD. On the other hand, the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway are one of the essential signaling pathways in various inflammatory diseases including AD. In particular, TSLP, IL-4, IL-13 and IL-22 occupy an important position for Th2 cell-mediated immune reaction. Moreover, experimentally pan-JAK inhibitor suppress the STAT3 activation and improved the skin barrier function. Furthermore TSLP, IL-4, IL-13 and IL-31 contribute a lot to chronic pruritus of AD, and transmitted via JAK-STAT pathway. Therefore, JAK inhibitors are promising candidates for the treatment of severe AD. Here we review clinical trials of topical dergocitinib; a pan-JAK inhibitor, ruxolitinib; a JAK1 and JAK2 inhibitor, and tofacitinib; a JAK1, JAK2, and JAK3 inhibitor and oral baricitinib; a JAK1 and JAK2 inhibitor, abrocitinib and upadacitinib; JAK1 inhibitor. Significant improvements in the symptoms were obtained by each drug with low frequency of adverse events. In particular, oral JAK inhibitors have the ability to improve the pruritus and skin symptoms quickly. Therefore, the emergence of these topical and oral JAK inhibitors would be regarded as an innovation in the treatment of atopic dermatitis.

Heat source and sink effects on periodic mixed convection flow along the electrically conducting cone inserted in porous medium.

The system of partial differential equations governing the unsteady hydromagnetic boundary-layer flow along an electrically conducting cone embedded in porous medium in the presence of thermal buoyancy, magnetic field, heat source and sink effects are formulated. These equations are solved numerically by using an implicit Finite-Difference Method. The effects of the various parameters that are source/sink parameter, porous medium parameter, Prandtl number, mixed convection parameter and magnetic Prandtl number on the velocity, temperature profiles, transverse magnetic field are predicted. The effects of heat source and sink parameter on the time-mean value as well as on transient skin friction; heat transfer and current density rate are delineated especially in each plot. The extensive results reveal the existence of periodicity and show that periodicity becomes more distinctive for source and sink in the case of the electrically conducting cone. As the source and sink contrast increases, the periodic convective motion is invigorated to the amplitude and phase angle as reflect in the each plot. The dimensionless forms of the set of partial differential equations is transform into primitive form by using primitive variable formulation and then are solved numerically by using Finite Difference Scheme which has given in literature frequently. Physical interpretations of the overall flow and heat transfer along with current density are highlighted with detail in results and discussion section. The main novelty of the obtained numerical results is that first we retain numerical results for steady part and then used in unsteady part to obtain transient skin friction, rate of heat transfer and current density. The intensity of velocity profile is increased for increasing values of porosity parameter Ω, the temperature and mass concentration intensities are reduced due heat source effects.

Novel Genes Potentially Involved in Fibroblasts of Diabetic Wound.

Fibroblasts are the essential cell type of skin, highly involved in the wound regeneration process. In this study, we sought to screen out the novel genes which act important roles in diabetic fibroblasts through bioinformatic methods. A total of 811 and 490 differentially expressed genes (DEGs) between diabetic and normal fibroblasts were screened out in GSE49566 and GSE78891, respectively. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways involved in type 2 diabetes were retrieved from miRWalk. Consequently, the integrated bioinformatic analyses revealed the shared KEGG pathways between DEG-identified and diabetes-related pathways were functionally enriched in the MAPK signaling pathway, and the MAPKAPK3, HSPA2, TGFBR1, and p53 signaling pathways were involved. Finally, ETV4 and NPE2 were identified as the targeted transcript factors of MAPKAPK3, HSPA2, and TGFBR1. Our findings may throw novel sight in elucidating the molecular mechanisms of fibroblast pathologies in patients with diabetic wounds and targeting new factors to advance diabetic wound treatment in clinic.

SKIN AND SUBCUTANEOUS ADIPOSE TISSUE DAMAGE AFTER RADIATION THERAPY IN BREAST CANCER PATIENTS. / POShKODZhENNIa ShKIRY I PIDShKIRNOÏ ZhYROVOÏ KLITKOVYNY PISLIa PROMENEVOÏ TERAPIÏ U KhVORYKh NA RAK MOLOChNOÏ ZALOZY.

The analysis of long-term researches of the pathological changes arising in soft tissues at patients with a breast cancer as a result of radical surgical treatment and adjuvant radiotherapy is carried out in work. The article shows that the standard approach to postoperative radiation therapy, which is based only on the prevalence of the primary tumor process is not always justified. Very often it leads to excessive radiation load on the patient's body and the development of local acute and chronic radiation reactions of the skin, subcutaneous tissue and other soft tissues.In this regard, the question of differentiated purpose of radiotherapy acquires special value first of all at patients with small primary prevalence of tumor process. The paper presents the results of studies to study changes in the anterior chest wall in patients with breast cancer. In relation to the conduct of adjuvant radiotherapy more often need to use the concept of personalized radiation therapy. Radical operation, post-radiation early and late pathological changes in soft tissues, disturbance of microcirculation of lymph and blood, disturbance of innervation of vessels of an upper extremity, peripheral nerves in system of a cervical and plexus plexus, leads to intensive degen-erative and dystrophic changes in soft tissues of the upper. and causes morphological changes in them and further progression of reflex neurovascular and neurodystrophic disorders. Based on the data of adverse effects of radio-therapy on the skin and surrounding tissues, as well as to reduce excessive radiation exposure to the patient's body, a differentiated approach to the appointment of adjuvant radiation therapy.

Microplasma Treatment versus Negative Pressure Therapy for Promoting Wound Healing in Diabetic Mice.

The delayed healing response of diabetic wounds is a major challenge for treatment. Negative pressure wound therapy (NPWT) has been widely used to treat chronic wounds. However, it usually requires a long treatment time and results in directional growth of wound healing skin tissue. We investigated whether nonthermal microplasma (MP) treatment can promote the healing of skin wounds in diabetic mice. Splint excision wounds were created on diabetic mice, and various wound healing parameters were compared among MP treatment, NPWT, and control groups. Quantitative analysis of the re-epithelialization percentage by detecting Ki67 and DSG1 expression in the extending epidermal tongue (EET) of the wound area and the epidermal proliferation index (EPI) was subsequently performed. Both treatments promoted wound healing by enhancing wound closure kinetics and wound bed blood flow; this was confirmed through histological analysis and optical coherence tomography. Both treatments also increased Ki67 and DSG1 expression in the EET of the wound area and the EPI to enhance re-epithelialization. Increased Smad2/3/4 mRNA expression was observed in the epidermis layer of wounds, particularly after MP treatment. The results suggest that the Smad-dependent transforming growth factor ß signaling contributes to the enhancement of re-epithelialization after MP treatment with an appropriate exposure time. Overall, a short-term MP treatment (applied for 30 s twice a day) demonstrated comparable or better efficacy to conventional NPWT (applied for 4 h once a day) in promoting wound healing in diabetic mice. Thus, MP treatment exhibits promise for treating diabetic wounds clinically.

Liver is a primary source of insulin-like growth factor-1 in skin wound healing.

Insulin-like growth factor (IGF)-1 plays important role in tissue repair through its ability to stimulate wound cell activity. While IGF-1 is expressed locally by wound cells, liver-derived IGF-1 is also present at high levels in the circulation, and the contributions of local vs circulating IGF-1 to wound levels remain undefined. The hypothesis of this study was that liver is a primary source of IGF-1 during skin wound healing. To test this hypothesis, we utilized a model that allows inducible ablation of IGF-1 specifically in liver of adult mice. We demonstrate that ablation of liver IGF-1 leads to >85% loss of circulating IGF-1 and ~60% decrease in wound IGF-1 during the proliferative phase of healing in both male and female mice. This reduction of liver-derived IGF-1 did not alter local mRNA expression of Igf1 in wounds. Knockdown of liver IGF-1 significantly delayed wound re-epithelialization and reduced granulation tissue formation and collagen deposition. Knockdown of liver IGF-1 also significantly reduced angiogenesis and resulted in persistent macrophage accumulation. In summary, liver is a primary source of IGF-1 in skin wounds and contributes to many aspects of both epithelial and dermal healing.

Defocused high-power diode laser accelerates skin repair in a murine model through REDOX state modulation and reepithelization and collagen deposition stimulation.

Skin wounds represent a burden in healthcare. Our aim was to investigate for the first time the effects of defocused high-power diode laser (DHPL) on skin healing in an animal experimental model and compare it with gold standard low-level laser therapy. Male Wistar rats were divided into 5 groups: Negative control; Sham; 0.1 W laser (L0.1 W); DHPL Dual 1 W (DHPLD1 W); and DHPL Dual 2 W (DHPLD2 W). Rats were euthanized on days 3, 5, 10, 14 and 21. Clinical, morphological, PicroSirus, oxidative stress (MDA, SOD and GSH) and cytokines (IL-1ß, IL-10 and TNF-α) analyses were performed. A faster clinical repair was observed in all laser groups at D10 and D14. DHPLD1 W exhibited lower inflammation and better reepithelization compared to other groups at D10. DHPL protocols modulated oxidative stress by decreasing MDA and increasing SOD and GSH. Collagen maturation was triggered by all protocols tested and L0.1 W modulated cytokines release (IL-1ß and TNF-α) at D3. In conclusion, DHPL, especially DHPL1 W protocol, accelerated skin healing by triggering reepithelization and collagen maturation and modulating inflammation and oxidative stress.

Skin Autofluorescence as a Novel and Noninvasive Technology for Advanced Glycation End Products in Diabetic Foot Ulcers: A Systematic Review and Meta-analysis.

OBJECTIVE: Skin autofluorescence (SAF) has been suggested as a novel and noninvasive technique for assessing tissue accumulation of advanced glycation end products in diabetes and related complications. The aim of this systematic review and meta-analysis was to evaluate the use of SAF in diabetic foot ulcers (DFUs). DATA SOURCES: PubMed/MEDLINE and other digital databases. STUDY SELECTION: The authors included studies comparing the SAF levels in patients with DFU with a non-DFU group to determine its association with DFU risk. DATA EXTRACTION: Collected data included the SAF method and its values in DFU and non-DFU groups, covariates used in adjustment along with the unadjusted and/or multivariate adjusted odds ratios (ORs) for the association of SAF with DFU risk, and other study characteristics. DATA SYNTHESIS: A total of six studies were included in this meta-analysis. Five studies that involved 611 participants were included to compare SAF methods. Compared with the non-DFU group, the DFU group showed a significantly increased level of SAF (standardized mean difference, 0.67; 95% confidence interval [CI], 0.32-1.01; P < .001). The results of meta-analysis of ORs revealed that the increased SAF level was independently associated with increased DFU risk in both unadjusted (OR, 3.16; 95% CI, 2.18-4.57; P < .001) and adjusted models (OR, 3.07; 95% CI, 1.95-4.81; P < .001). CONCLUSIONS: These findings suggest that SAF could be useful as a novel and noninvasive technology to help determine DFU risk. However, further studies establishing its diagnostic and prognostic utilities are needed.

Cutaneous Pathology of COVID-19 as a Window into Immunologic Mechanisms of Disease.

Many skin manifestations of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection reflect activation of cutaneous and systemic immune responses involving effector pathways of both the innate and adaptive arms of the immune system. This article reviews evidence from the recent clinical and scientific literature that informs the current understanding of the consequences of coronavirus disease 2019 (COVID-19)-induced immune cell activation, as relevant to dermatology. Topics include the clinical consequences of autoantibody production in patients with COVID-19, immunologic evidence for chilblains as a manifestation of SARS-CoV-2 infection, and the relationship between type I interferons and COVID-19 disease severity.

Whole-body clonal mapping identifies giant dominant clones in zebrafish skin epidermis.

Skin expansion during development is predominantly driven by growth of basal epithelial cell (BEC)-derived clonal populations, which often display varied sizes and shapes. However, little is known about the causes of clonal heterogeneity and the maximum size to which a single clone can grow. Here, we created a zebrafish model, basebow, for capturing clonal growth behavior in the BEC population on a whole-body, centimeter scale. By tracking 222 BECs over the course of a 28-fold expansion of body surface area, we determined that most BECs survive and grow clonal populations with an average size of 0.013 mm2. An extensive survey of 742 sparsely labeled BECs further revealed that giant dominant clones occasionally arise on specific body regions, covering up to 0.6% of the surface area. Additionally, a growth-induced extracellular matrix component, Lamb1a, mediates clonal growth in a cell-autonomous manner. Altogether, our findings demonstrate how clonal heterogeneity and clonal dominance may emerge to enable post-embryonic growth of a vertebrate organ, highlighting key cellular mechanisms that may only become evident when visualizing single cell behavior at the whole-animal level.

Keratin-Alginate Sponges Support Healing of Partial-Thickness Burns.

Deep partial-thickness burns damage most of the dermis and can cause severe pain, scarring, and mortality if left untreated. This study serves to evaluate the effectiveness of crosslinked keratin-alginate composite sponges as dermal substitutes for deep partial-thickness burns. Crosslinked keratin-alginate sponges were tested for the ability to support human dermal fibroblasts in vitro and to support the closure and healing of partial-thickness burn wounds in Sus scrofa pigs. Keratin-alginate composite sponges supported the enhanced proliferation of human dermal fibroblasts compared to alginate-only sponges and exhibited decreased contraction in vitro when compared to keratin only sponges. As dermal substitutes in vivo, the sponges supported the expression of keratin 14, alpha-smooth muscle actin, and collagen IV within wound sites, comparable to collagen sponges. Keratin-alginate composite sponges supported the regeneration of basement membranes in the wounds more than in collagen-treated wounds and non-grafted controls, suggesting the subsequent development of pathological scar tissues may be minimized. Results from this study indicate that crosslinked keratin-alginate sponges are suitable alternative dermal substitutes for clinical applications in wound healing and skin regeneration.

Oxidative stress and its impact on skin, scalp and hair.

Oxidative stress is an unbalanced condition in which the tissues of the body are not sufficiently able to counteract either exogenous or endogenous sources of reactive oxygen species. Oxidative stress is strongly associated with ageing, both local and systemic, as well as a wide range of local health conditions. This review focuses on the oxidative stress data known for skin, scalp and hair. This oxidative stress may be the 'currency' by which an unhealthy scalp leads to deleterious consequences to the hair. The ramifications of this scalp oxidative stress to normal hair elongation, retention and replacement are discussed.

Le stress oxydatif est une condition déséquilibrée dans laquelle les tissus du corps ne sont pas suffisamment capables de contrer la source exogène ou endogène d'espèces réactives de l'oxygène. Le stress oxydatif est fortement associé au vieillissement, à la fois local et systémique, ainsi qu'à un large éventail de problèmes de santé locaux. Cette revue se concentre sur les données de stress oxydatif connues pour la peau, le cuir chevelu et les cheveux. Ce stress oxydatif peut être la « devise ¼ par laquelle un cuir chevelu malsain entraîne des conséquences délétères pour les cheveux. Les ramifications de ce stress oxydatif du cuir chevelu sur l'allongement, la rétention et le remplacement normaux des cheveux sont discutées.