RESUMO
Angiogenesis has been recognised as a precursor of fibrosis in several pathologic conditions. Its participation has been demonstrated in schistosomiasis, both during periovular granuloma formation and in the genesis of schistosomal periportal fibrosis. Paradoxically, proliferation of new blood vessels, accompanied by production of vascular-endothelial growth factor, appeared prominent during fibrosis regression months after curative treatment of schistosomiasis. Thus, angiogenesis in schistosomiasis seems to have a two-way mode of action, participating both in fibrogenesis and in fibrosis degradation. Morphological observations presented here are in keeping with the possibility that, in the first case, angiogenesis allows pericytes to come in great numbers to the site of lesions and be detached from capillary walls and transformed into myofibroblasts, which are important extra-cellular matrix forming cells. During post-curative fibrosis regression, actin-containing pericytes appeared at various foci of tissue remodelling, especially at sites of repair of vascular lesions. The molecular and cell factors involved in both situations seem to be important subjects in need of further investigations and the schistosomiasis model certainly will be of great avail in this regard.
Assuntos
Granuloma/parasitologia , Cirrose Hepática/parasitologia , Neovascularização Patológica/parasitologia , Esquistossomose mansoni/fisiopatologia , Animais , Granuloma/patologia , Granuloma/fisiopatologia , Humanos , Cirrose Hepática/patologia , Cirrose Hepática/fisiopatologia , Camundongos , Neovascularização Patológica/patologia , Neovascularização Patológica/fisiopatologia , Pericitos/fisiologia , Esquistossomose mansoni/patologiaRESUMO
The relationship between angiogenesis and fibrosis has been demonstrated in several pathological conditions, one of them being schistosomiasis. To observe whether suppression of angiogenesis would interfere with fibrosis, Thalidomide, an anti-angiogenesis drug, was administered during 30 consecutive days to mice with experimental schistosomiasis. Computerized morphometric measurements of fibrosis, and the counting of blood vessels from hepatic schistosomal lesions did not significantly differ when treated animals and their controls were compared at the end of the experiments. These rather unexpected results are presented under the understanding that they may be of interest during further studies on the anti-angiogenesis properties of thalidomide, and the relationship between angiogenesis and fibrosis.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Cirrose Hepática/prevenção & controle , Fígado/irrigação sanguínea , Neovascularização Patológica/prevenção & controle , Esquistossomose mansoni/patologia , Talidomida/uso terapêutico , Animais , Modelos Animais de Doenças , Feminino , Fígado/parasitologia , Cirrose Hepática/parasitologia , Cirrose Hepática/patologia , Masculino , Camundongos , Neovascularização Patológica/parasitologiaRESUMO
The relationship between angiogenesis and fibrosis has been demonstrated in several pathological conditions, one of them being schistosomiasis. To observe whether suppression of angiogenesis would interfere with fibrosis, Thalidomide, an anti-angiogenesis drug, was administered during 30 consecutive days to mice with experimental schistosomiasis. Computerized morphometric measurements of fibrosis, and the counting of blood vessels from hepatic schistosomal lesions did not significantly differ when treated animals and their controls were compared at the end of the experiments. These rather unexpected results are presented under the understanding that they may be of interest during further studies on the anti-angiogenesis properties of thalidomide, and the relationship between angiogenesis and fibrosis.
Assuntos
Animais , Feminino , Masculino , Camundongos , Inibidores da Angiogênese/uso terapêutico , Cirrose Hepática/prevenção & controle , Fígado/irrigação sanguínea , Neovascularização Patológica/prevenção & controle , Esquistossomose mansoni/patologia , Talidomida/uso terapêutico , Modelos Animais de Doenças , Cirrose Hepática/parasitologia , Cirrose Hepática/patologia , Fígado/parasitologia , Neovascularização Patológica/parasitologiaRESUMO
An increasing amount of evidences points to angiogenesis as playing a paramount role in fibrosis development. However granulomas in general, and periovular schistosomal granulomas in particular, are considered avascular structures, although they usually result in dense areas of focal fibrosis. In order to clarify this apparent paradox, the presence of blood vessels was systematically searched in hepatic schistosomal granulomas of mice, during different stages of the infection, and at different stages of granuloma evolution, by means of vascular injections of colored masses, demonstration of laminin in vascular basement membranes and by ultra structural analysis. Vascular proliferation appeared evident at the early stages of granuloma formation, gradually decreasing thereafter, older granulomas becoming almost avascular structures, sometimes delimited at the periphery by a rich vascular network.
Assuntos
Granuloma/parasitologia , Hepatopatias Parasitárias/patologia , Neovascularização Patológica/parasitologia , Schistosoma mansoni , Esquistossomose mansoni/patologia , Animais , Modelos Animais de Doenças , Feminino , Fibrose/parasitologia , Fibrose/patologia , Granuloma/patologia , Camundongos , Neovascularização Patológica/patologia , Fatores de TempoRESUMO
An increasing amount of evidences points to angiogenesis as playing a paramount role in fibrosis development. However, granulomas in general, and periovular schistosomal granulomas in particular, are considered avascular structures, although they usually result in dense areas of focal fibrosis. In order to clarify this apparent paradox, the presence of blood vessels was systematically searched in hepatic schistosomal granulomas of mice, during different stages of the infection, and at different stages of granuloma evolution, by means of vascular injections of colored masses, demonstration of laminin in vascular basement membranes and by ultra structural analysis. Vascular proliferation appeared evident at the early stages of granuloma formation, gradually decreasing thereafter, older granulomas becoming almost avascular structures, sometimes delimited at the periphery by a rich vascular network.