Investigation of serum substance P status in patients with chronic pruritic skin lesions due to sulfur mustard: a cross-sectional study

Mas-related G protein-coupled receptor X2 and its activators in dermatologic allergies

The Mas-related G protein-coupled receptor X2 (MRGPRX2) is a multiligand receptor responding to various exogenous and endogenous stimuli. Being highly expressed on skin mast cells, MRGPRX2 triggers their degranulation and release of proinflammatory mediators, and it promotes multicellular signaling cascades, such as itch induction and transmission in sensory neurons. The expression of MRGPRX2 by skin mast cells and the levels of the MRGPRX2 agonists (eg, substance P, major basic protein, eosinophil peroxidase) are upregulated in the serum and/or skin of patients with inflammatory and pruritic skin diseases, such as chronic spontaneous urticaria or atopic dermatitis. Therefore, MRGPRX2 and its agonists might be potential biomarkers for the progression of cutaneous inflammatory diseases and the response to treatment. In addition, they may represent promising targets for prevention and treatment of signs and symptoms in patients with skin diseases or drug reactions. To assess this possibility, this review explores the role and relevance of MRGPRX2 and its activators in cutaneous inflammatory disorders and chronic pruritus.

Tachykinin upregulation in atopic dermatitis

Context: Atopic dermatitis (AD) is a chronic, inflammatory, itching skin disorder, which may worsen due to stress, depression and anxiety. Tachykinins may be involved in inflammation signaling as well as they may have a role in stress, depression and anxiety. Objective: This study aimed to measure the expression of tachykinin markers, in the skin of patients with AD, and the correlation of these tachykinins with clinical and psychodemographic parameters. Materials and methods: Twenty-eight adult patients with AD were investigated regarding tachykinin expression in skin biopsies, using an immunohistochemical technique. The patients were characterized with clinical and psychodemographic parameters. Results: The number of substance P and neurokinin (NK)A positive nerve fibers, as well as NKA positive mononuclear dermal cells, was increased in lesional compared to non-lesional skin. Interestingly, the depression score and the number of dermal NK-1 receptor (R) positive cells in lesional as well as in non-lesional skin showed a correlation. Conclusion: These findings indicate an upregulation of the tachykinergic system in the inflamed skin of AD.

TRPA1 and CGRP antagonists counteract vesicant-induced skin injury and inflammation

The skin is highly sensitive to the chemical warfare agent in mustard gas, sulfur mustard (SM) that initiates a delayed injury response characterized by erythema, inflammation and severe vesication (blistering). Although SM poses a continuing threat, used as recently as in the Syrian conflict, no mechanism-based antidotes against SM are available. Recent studies demonstrated that Transient Receptor Potential Ankyrin 1 (TRPA1), a chemosensory cation channel in sensory nerves innervating the skin, is activated by SM and 2-chloroethyl ethyl sulfide (CEES), an SM analog, in vitro, suggesting it may promote vesicant injury. Here, we investigated the effects of TRPA1 inhibitors, and an inhibitor of Calcitonin Gene Related Peptide (CGRP), a neurogenic inflammatory peptide released upon TRPA1 activation, in a CEES-induced mouse ear vesicant model (CEES-MEVM). TRPA1 inhibitors (HC-030031 and A-967079) and a CGRP inhibitor (MK-8825) reduced skin edema, pro-inflammatory cytokines (IL-1β, CXCL1/KC), MMP-9, a protease implicated in skin damage, and improved histopathological outcomes. These findings suggest that TRPA1 and neurogenic inflammation contribute to the deleterious effects of vesicants in vivo, activated either directly by alkylation, or indirectly, by reactive intermediates or pro-inflammatory mediators. TRPA1 and CGRP inhibitors represent new leads that could be considered for validation and further development in other vesicant injury models.

Epidermal hydration and skin surface lipids in patients with long-term complications of sulfur mustard poisoning

Background:

Despite almost the three decades passed since the chemical attacks of Iraqi's army against the Iranian troops, some veterans are still suffering from long-term complications of sulfur mustard (SM) poisoning, including certain skin complaints specially dryness, burning, and pruritus. We thus aimed to evaluate the skin's water and lipid content in patients with a disability of >25% due to complications of SM poisoning and compare them with a matched control group.

Materials and Methods:

Sixty-nine male participants were included in this study; 43 SM-exposed patients, and 26 normal controls from their close relatives. The water and lipid content was measured in four different locations: Extensor and flexor sides of forearms and lateral and medial sides of legs by the Corneometer CM 820/Sebumeter SM 810. Collected data was analyzed and P ≤ 0.05 was considered as statistically significant.

Results:

The mean age of the patients and controls was 49.53 ± 11.34 (ranges: 40-71) and 29.08 ± 8.836 (ranges: 15-49 years), respectively. In the veterans group, the main cutaneous complaint was itching and skin dryness. Cherry angioma, dry skin, and pruritus were significantly more common in the SM-exposed cases than in the controls. (P = 0.01, 0.05, and 0.04, respectively). The moisture and lipid content of all areas were lower in the SM-exposed group, but it was only significant in skin sebum of lateral sides of legs (P = 0.02).

Conclusion:

Exposure to SM could decrease the function of stratum corneum and lipid production as a barrier, even after several years of its exposure.

Topical cyclosporine a for treatment of dry eye due to chronic mustard gas injury

Purpose:

To evaluate the efficacy of topical cyclosporine A (tCsA) for treatment of dry eye disease in patients suffering from chronic ocular complications of mustard gas (MG) injury.

Methods:

This interventional case series included patients with MG injury suffering from severe dry eye despite receiving artificial tears and punctal plugs. Patients were administered tCsA 0.05% twice daily for 3 months. Severity of the condition was evaluated by measuring tear osmolarity, ocular surface disease index (OSDI), tear break-up time (TBUT), and Schirmer's test at baseline and at the end of study.

Results:

A total of 34 patients with chronic MG injury and mean age of 47.1 ± 6.5 years were studied. Compared to baseline values, tear osmolarity (301.7 ± 11.5 vs. 286.3 ± 7.9 mOsmol/L, P < 0.001) and OSDI (47.5 ± 7.2 vs. 42.7 ± 7.1, P < 0.001) were significantly improved. Likewise, Schirmer's test (4.6 ± 1.3 vs. 5 ± 1.3 mm, P < 0.001) and TBUT (1.9 ± 1.4 vs. 2.7 ± 1.5 s, P < 0.001) also significantly recovered at the end of the study.

Conclusion:

TCsA 0.05% reduces tear osmolarity and improves dry eye symptoms and can serve as an efficacious treatment for ocular complications in patients with chronic MG injury.

Serum level of substance P in patients with lung injuries due to sulfur mustard

Background:

Chronic bronchiolitis is the most important problems of chemical victims of mustard gas. Diverse studies suggest that substance P (SP) as a member of tachykinin neuropeptides, has a significant role in the neurogenic inflammation processes of the airways and lungs. We aimed to determine the serum level of SP in chemical victims of mustard gas and compare it with normal subjects.

Materials and Methods:

The chemical victims were divided into the 2 groups of 30:A group with mild to moderate pulmonary symptoms and other group with moderate to severe symptoms and compared with 3^rd group as healthy controls. After preparing our samples and using the SP kit, final analysis was performed with enzyme-linked immunosorbent assay reader.

Results:

The Concentration of circulatory SP levels in the chemical patients was 2.86 ± 1.47 ng/ml and had not a significant difference with the control group (3.15 ± 1.03 ng/ml) (P > 0.05). The circulatory SP levels were 2.48 ± 0.92 ng/ml and 3.28 ± 1.73 ng/ml in patients with moderate to severe symptoms and mild to moderates (P < 0.05) respectively.

Conclusion:

The SP may have a role in pulmonary complications of mustard gas. The lower level of SP in the moderate to severe patients may be due to corticosteroid consumption in such severe cases. However, further studies are needed to clarify the roles and mechanism of SP in this setting.