RESUMEN
Blister formation and skin damage can be induced by BaP1, a haemorrhagic metalloproteinase from the venom of the snake Bothrops asper. Pathological changes in the skin were investigated after intramuscular injections of Bothrops asper haemorrhagic metalloproteinase BaP1. Blisters developed within the first hour, with separation of epidermis from the dermal-epidermal junction, whereas acantholysis of epithelial cells was not observed. After the third hour there was ulceration with formation of a proteinaceous scab and inflammatory infiltrate. By 7 to 14 days there was evidence of a regenerative process in dermis and epidermis. Haemorrhage occurred in both dermis and hypodermis as a consequence of BaP1 injection, together with damage of sebaceous glands and an inflammatory reaction in which enlarged macrophages were the predominant cell type. Zymography assays showed the presence of several endogenous metalloproteinases in the exudate, skin homogenates and plasma. In addition, BaP1 was detected in exudates and plasma by immunoblotting. This technique also demonstrated the presence of components immunologically related to laminin and collagen type IV in exudates. It is suggested that BaP1, and probably endogenous matrix metalloproteinases, degrade some protein components at the dermal-epidermal junction, inducing the formation of blisters.
Asunto(s)
Bothrops , Venenos de Crotálidos/toxicidad , Metaloendopeptidasas/toxicidad , Enfermedades de la Piel/inducido químicamente , Animales , Vesícula/inducido químicamente , Vesícula/enzimología , Vesícula/patología , Electroforesis en Gel de Poliacrilamida , Proteínas de la Matriz Extracelular/metabolismo , Exudados y Transudados/enzimología , Exudados y Transudados/metabolismo , Gelatinasas/metabolismo , Immunoblotting , Metaloendopeptidasas/metabolismo , Ratones , Enfermedades de la Piel/enzimología , Enfermedades de la Piel/patologíaRESUMEN
Tyrosinase-positive albinism, previously diagnosed as Hermansky-Pudlak Syndrome (HPS), has been examined in four generations from a village of the canton Valais, Switzerland. Homozygotes, obligate heterozygotes and putative heterozygotes in this geneology yielded lower than normal membrane-associated thioredoxin reductase (TR) activities compared with normal family members and controls. All of the homozygotes and 50% of each the obligate and putative heterozygotes showed an increase in bleeding time associated with storage-pool-deficient platelets lacking dense bodies. The TR activity profile and the platelet-dense body deficiency in the Swiss albinos was the same as that in the HPS population from Puerto Rico. However, in albinos from Puerto Rico, there is an accumulation of ceroid/lipofuscin-like pigment in lysosomal structures causing tissue damage, and, upon kidney involvement, this leads to increased urinary dolichol excretion. Approximately half of the Puerto Rican HPS cases had clinical evidence of storage disease with restrictive lung disease, granulomatous colitis, kidney failure and cardiomyopathy. By comparison, the Swiss HPS geneology had a normal life expectancy with no significant evidence for ceroid accumulation or urinary dolichol excretion. An examination of antioxidant enzymes, catalase, TR and glutathione reductase in epidermal suction blisters from Swiss HPS homozygotes showed a similar result for catalase and TR levels to the depigmented epidermis of patients with vitiligo, except that intracellular TR was found to be calcium free in HPS compared with vitiligo. Intracellular glutathione reductase levels were highest in HPS. Both the Swiss and Puerto Rican HPS homozygotes and heterozygotes have giant melanosomes in skin melanocytes.