El papel de la FAK en la acantólisis del Pénfigo vulgar en un modelo murino

Pemphigus vulgaris (PV) is an autoimmune blistering skin disease characterized by suprabasal acantholysis, and autoantibodies against desmoglein 3 localized on desmosomes. In addition, caspases also seem to participate in this blistering disease. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase involved in cytoskeleton remodelling and formation and disassembly of cell adhesion structures. We have previously demonstrated that HER (human epidermal growth factor receptor related) isoforms, Src (Rous sarcoma) and mTOR (mammalian target of rapamycin), three molecules implicated in signalling processes, take part in suprabasal acantholysis and apoptosis induced by PV-IgG in a mouse model. Our aim was to investigate if upregulation of FAK is implicated in the development of PV lesions. Herein, using a mouse model, PV-IgG administration showed an increased level of FAK phosphorylated on 397 and 925 tyrosine residues in the basal layer of epidermis. When mice were pretreated with a FAK inhibitor the acantholysis of the basal layer of epidermis was absent. More interestingly, we observed that phosphorylated FAK (Y397/925) decreased when HER isoforms, Src, mTOR, and pan-caspases inhibitors were employed before PV-IgG administration. In addition, pretreatment with the FAK inhibitor before PV-IgG injection avoided the changes of both Bax and Bcl-2 expression and caspases-9 and –3 activities induced by PV-IgG. Finally, FAK inhibitor reduced expression of phosphorylated Src and mTOR in the basal cells of epidermis. In conclusion, our data reveal a novel biochemical mechanism for phosphorylated FAK (Y397/925) in PV development involving HER isoforms, Src and mTOR kinases

El papel de la FAK en la acantólisis del Pénfigo vulgar en un modelo murino

Pemphigus vulgaris (PV) is an autoimmune blistering skin disease characterized by suprabasal acantholysis, and autoantibodies against desmoglein 3 localized on desmosomes. In addition, caspases also seem to participate in this blistering disease. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase involved in cytoskeleton remodelling and formation and disassembly of cell adhesion structures. We have previously demonstrated that HER (human epidermal growth factor receptor related) isoforms, Src (Rous sarcoma) and mTOR (mammalian target of rapamycin), three molecules implicated in signalling processes, take part in suprabasal acantholysis and apoptosis induced by PV-IgG in a mouse model. Our aim was to investigate if upregulation of FAK is implicated in the development of PV lesions. Herein, using a mouse model, PV-IgG administration showed an increased level of FAK phosphorylated on 397 and 925 tyrosine residues in the basal layer of epidermis. When mice were pretreated with a FAK inhibitor the acantholysis of the basal layer of epidermis was absent. More interestingly, we observed that phosphorylated FAK (Y397/925) decreased when HER isoforms, Src, mTOR, and pan-caspases inhibitors were employed before PV-IgG administration. In addition, pretreatment with the FAK inhibitor before PV-IgG injection avoided the changes of both Bax and Bcl-2 expression and caspases-9 and –3 activities induced by PV-IgG. Finally, FAK inhibitor reduced expression of phosphorylated Src and mTOR in the basal cells of epidermis. In conclusion, our data reveal a novel biochemical mechanism for phosphorylated FAK (Y397/925) in PV development involving HER isoforms, Src and mTOR kinases

Popper’s Dermatitis: An Unusual Diagnostic Challenge

Volatile nitrites, and especially isobutyl nitrite or “Popper”, are popular drugs of abuse in Europe, mainly in men that have sex with men (MSM). Inhalation is the most common route of consumption, but direct contact with skin or muco- sal membranes has been associated with a local adverse event called “Popper’s dermatitis”. To date, just five cases have been reported, most of them on the face, but also on other parts of the body [1, 2]

Cocaine-induced pyoderma gangrenosum-like lesions

Cocaine consumption is increasing at an alarming rate. This drug produces euphoria, anorexia, increased alertness and diminished sleep requirements. It is estimated that up to 80 % of cocaine is contaminated with levamisole, a substance which may potentiate the drug’s chemical effects [ 1 ] . Multiple mucocutaneous manifestations have been associated with cocaine use [ 2 ] , including cocaine-induced pyoderma gangre-nosum (CIPG), cocaine-induced midline destructive lesions (CIMDL) and retiform purpura (RP). We present three cases of cocaine abuse with skin lesions compatible with PG, and review the epidemiological, clinical, histopathological and immunological characteristics of CIPG and RP. We suggest that these two conditions are more closely related than previously thought. Additionally, in our opinion, no specific immunological or histological profile would be indicative of levamisole toxicity

A Comparative Study of Sex Distribution, Autoimmunity, Blood, and Inflammatory Parameters in Chronic Spontaneous Urticaria with Angioedema and Chronic Histaminergic Angioedema

Background Recurrent idiopathic histaminergic angioedema is currently classified as a subtype of angioedema, as well as a subtype of chronic spontaneous urticaria (CSU), based on the fact that both are mast cell-mediated and respond to the same treatments. Objective In the present work, we sought to verify whether chronic histaminergic angioedema (CHA) is an entity distinct from CSU or represents a CSU subtype that lacks hives. Methods We performed a prospective study comparing 68 CHA patients, angioedema without hives, with 63 CSU patients, with hives and angioedema, from whom we collected demographic and clinical data, as well as blood and serum markers. Results We found key pathogenic features that differentiate CHA from CSU: gender distribution, basophil number, and antibodies against the IgE receptor. The male/female ratio in CHA was 0.78, whereas in CSU it was 0.36 (P = .0466). Basopenia was more often seen in CSU (n = 13 [20%]) than in CHA (n = 5 [7%]). Finally, 31.15% of CSU sera induced basophil activation, whereas no CHA sera were able to activate normal basophils. By contrast, nonspecific inflammation or immune markers, for example, erythrocyte sedimentation rate, C-reactive protein, or IgG antithyroid antibodies, were very similar between both groups. IgE anti–IL-24 could not be assessed because a control population did not differ from CSU. Conclusions Inclusion of CHA as part of the spectrum of CSU is an assumption not evidence-based, and when studied separately, important differences were observed. Until there is further evidence, CHA and CSU should not necessarily be considered the same disorder, and it is our opinion that review articles and guidelines should reflect that possibility

Risk factors and rate of recurrence after Mohs surgery in basal cell and squamous cell carcinomas: a nationwide prospective cohort (REGESMOHS, Spanish Registry of Mohs Surgery)

Randomized studies to assess the efficacy of Mohs micrographic surgery in basal cell and squamous cell carcinomas are limited by methodological and ethical issues and a lack of long follow-up periods. This study presents the "real-life" results of a nationwide 7-years cohort on basal cell carcinoma and squamous cell carcinoma treated with Mohs micrographic surgery. A prospective cohort was conducted in 22 Spanish centres (from July 2013 to February 2020) and a multivariate analysis, including characteristics of patients, tumours, surgeries and follow-up, was performed. A total of 4,402 patients followed up for 12,111 patient-years for basal cell carcinoma, and 371 patients with 915 patient-years of follow-up for squamous cell carcinoma were recruited. Risk factors for recurrence included age, non-primary tumours and more stages or unfinished surgeries for both tumours, and immunosuppression for squamous cell carcinoma. Incidence rates of recurrence were 1.3 per 100 person-years for basal cell carcinoma (95% confidence interval 1.1-1.5) and 4.5 for squamous cell carcinoma (95% confidence interval 3.3-6.1), being constant over time (0-5 years). In conclusion, follow-up strategies should be equally intense for at least the first 5 years, with special attention paid to squamous cell carcinoma (especially in immunosuppressed patients), elderly patients, non-primary tumours, and those procedures requiring more stages, or unfinished surgeries