Neurogenic inflammation of the skin observed after topical application of an irritant substance or environmental stimulation induces vascular changes and the production of inflammatory mediators. Substance P (SP) is one of the main neuropeptides which trigger an inflammatory response in the skin. So, with the aim to develop an alternative method to study neurogenic inflammation of the skin, we used an organ culture of human skin. SP was added onto epidermis or directly to culture medium in an attempt to reproduce ex vivo the effects described in vivo. Even disconnected from systemic blood circulation, in skin fragments in culture, we observed dose-dependent edema, vasodilation and extravasation of lymphocytes and mast cells through the microvascular wall. Moreover, the release of proinflammatory mediators interleukin 1α and tumor necrosis factor α was evidenced.
Background: Acral erythema on the palms is observed in several conditions. However, the relationship with malignant tumors has only been reported exceptionally. It should be noted that tumors produce angiogenic mediators. Objective: These mediators might promote palmar erythema (PE), and the aim of the present study was to investigate the vasodilation of palmar skin capillaries and angiogenesis, mainly with tumors of the central nervous system. Methods: In a prospective study of 107 patients affected by brain tumors, we assessed PE clinically and the rate of dilated vessels histologically. We also evaluated the mean surface of the lumen of capillaries on skin biopsies and brain tumors. Results: 6.5% of the patients had an important erythema and 18.5% had slight and/or localized PE. In the skin biopsies, the rate of dilated vessels and the mean surface of the lumen of capillaries were higher than in normal skin. Moreover, the intensity of palmar redness was related to the increase in these vascular changes in the histopathological slices of brain tumors. The intensity also depended on the type of tumor and on its growth. Conclusion: The results of the present study strongly suggest that acral erythema is associated with malignant tumors and that the intensity of erythema and the vascular changes of brain tumors are related, probably due to angiogenic factors.
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