Envenomations by Bothrops and Crotalus Snakes Induce the Release of Mitochondrial Alarmins

Skeletal muscle necrosis is a common manifestation of viperid snakebite envenomations. Venoms from snakes of the genus Bothrops, such as that of B. asper, induce muscle tissue damage at the site of venom injection, provoking severe local pathology which often results in permanent sequelae. In contrast, the venom of the South American rattlesnake Crotalus durissus terrificus, induces a clinical picture of systemic myotoxicity, i.e., rhabdomyolysis, together with neurotoxicity. It is known that molecules released from damaged muscle might act as ‘danger’ signals. These are known as ‘alarmins’, and contribute to the inflammatory reaction by activating the innate immune system. Here we show that the venoms of B. asper and C. d. terrificus release the mitochondrial markers mtDNA (from the matrix) and cytochrome c (Cyt c) from the intermembrane space, from ex vivo mouse tibialis anterior muscles. Cyt c was released to a similar extent by the two venoms whereas B. asper venom induced the release of higher amounts of mtDNA, thus reflecting hitherto some differences in their pathological action on muscle mitochondria. At variance, injection of these venoms in mice resulted in a different time-course of mtDNA release, with B. asper venom inducing an early onset increment in plasma levels and C. d. terrificus venom provoking a delayed release. We suggest that the release of mitochondrial ‘alarmins’ might contribute to the local and systemic inflammatory events characteristic of snakebite envenomations

Dermatoses bolhosas auto-imunes Autoimmune bullous dermatoses

Dermatoses bolhosas autoimunes são doenças cuja manifestação cutânea primária e fundamental consiste em vesículas e bolhas. Classificam-se conforme a localização da bolha, em intraepidérmica e subepidérmica. Os pacientes produzem autoanticorpos contra estruturas específicas da pele detectáveis por técnicas de imunofluorescência, immunobloting e Elisa. Os recentes avanços da biologia molecular e celular têm permitido conhecer esses autoantígenos, contra os quais os pacientes se sensibilizam e que estão localizados na epiderme ou na junção dermoepidérmica. São doenças de baixa incidência, porém de elevada morbidade e por vezes letais. O objetivo deste trabalho é revisar e descrever os progressos nos conhecimentos de quatro doenças vésico-bolhosas autoimunes: pênfigo foliáceo endêmico (fogo selvagem), pênfigo vulgar, penfigóide bolhoso e dermatite herpetiforme.<br>Autoimmune bullous dermatoses are diseases in which blisters and vesicles are the primary and fundamental types of skin lesion. Their classification is based on the location of the blister: intraepidermal and subepidermal. Patients produce autoantibodies against self-specific structures of the skin detectable by immunofluorescence techniques, immunoblotting and ELISA. Recent advances in molecular and cellular biology have brought to knowledge these self-antigens, against which patients are sensitized, and which are found in epidermis or in the dermo-epidermal junction. These are low incidence, but high morbidity diseases that may be fatal. The aim of this article is to review and describe the progress of four autoimmune vesiculobullous disorders: endemic pemphigus foliaceous (wild fire), pemphigus vulgaris, bullous pemphigoid and dermatitis herpetiformis