RESUMO
PURPOSE: Although the cardioprotective benefits of exercise training are well known, the effects of training on dexamethasone (DEX)-induced arterial stiffness are still unclear. This study was aimed at investigating the mechanisms induced by training to prevent DEX-induced arterial stiffness. METHODS: Wistar rats were allocated into 4 groups and submitted to combined training (aerobic and resistance exercises, on alternate days, 60% of maximal capacity, for 74 d) or were kept sedentary: sedentary control rats (SC), DEX-treated sedentary rats (DS), combined training control (CT), and DEX-treated trained rats (DT). During the last 14 d, rats were treated with DEX (50 µg/kg per body weight, per day, s.c.) or saline. RESULTS: DEX increased PWV (+44% vs +5% m/s, for DS vs SC, p<0.001) and increased aortic COL 3 protein level (+75%) in DS. In addition, PWV was correlated with COL3 levels (r=0.682, p<0.0001). Aortic elastin and COL1 protein levels remained unchanged. On the other hand, the trained and treated groups showed lower PWV values (-27% m/s, p<0.001) vs DS and lower values of aortic and femoral COL3 compared with DS. CONCLUSION: As DEX is widely used in several situations, the clinical relevance of this study is that the maintenance of good physical capacity throughout life can be crucial to alleviate some of its side effects, such as arterial stiffness.
RESUMO
BACKGROUND: Tracheal stenosis (TS) is a complication of prolonged intubation, tracheotomy, and tracheal surgery that compromises the vascular supply. Animal models are essential for studying its pathophysiology and the effect of interventions. OBJECTIVE: To establish a TS model in rats secondary to tracheal autotransplantation with a graft submerged in bleomycin (Atx-Bleo). Additionally, to evaluate the clinical and histological changes, as well as the expression of newly formed collagen (NFC), isoforms of transforming growth factor beta (TGFß), fibronectin (FN), elastin (ELN), integrin ß1 (ITGß1), and matrix metalloproteinase 1 (MMP1) in TS. METHODS: Twenty Wistar rats were divided into three groups: group I (n = 20) control; group II (n = 10) end-to-end anastomosis of the trachea (tracheoplasty); and group III (n = 10) Atx-Bleo. The animals were evaluated clinically, tomographically, macroscopically, morphometrically, and microscopically. NFC deposition, and the expression of profibrotic and antifibrotic proteins were evaluated in tracheal scars. RESULTS: All animals survived the surgical procedure and the study period. Compared with the other study groups, the Atx-Bleo group developed TS and fibrosis, exhibited higher expression of NFC, TGFß1, TGFß2, FN, ELN, and ITGß1, and mild expression of TGFß3 and MMP1 (p < 0.005; analysis of variance, Dunnett and Tukey tests). CONCLUSION: Atx-Bleo in TS model rats produces tomographic and histological changes, and induces the upregulation of profibrotic proteins (TGFß1, TGFß2, collagen, FN, ELN, ITGß1) and downregulation of antifibrotic proteins (TGFß3, MMP1). Therefore, this model may be used to test new pharmacological treatments for reversing or preventing TS, and conduct basic studies regarding its pathophysiology.
Assuntos
Estenose Traqueal , Animais , Colágeno/metabolismo , Matriz Extracelular , Proteínas da Matriz Extracelular/metabolismo , Metaloproteinase 1 da Matriz/metabolismo , Ratos , Ratos Wistar , Traqueia/metabolismo , Traqueia/patologia , Traqueia/cirurgia , Estenose Traqueal/etiologia , Estenose Traqueal/patologia , Estenose Traqueal/cirurgia , Transplante AutólogoRESUMO
Posaconazole (POS) is an inhibitor of ergosterol biosynthesis in clinical use for treating invasive fungal infections. POS has potent and selective anti-Trypanosoma cruzi activity and has been evaluated as a possible treatment for Chagas disease. Microtissues are a 3D culture system that has been shown to reproduce better tissue architecture and functionality than cell cultures in monolayer (2D). It has been used to evaluate chemotropic response as in vitro disease models. We previously developed an in vitro model that reproduces aspects of cardiac fibrosis observed in Chagas cardiomyopathy, using microtissues formed by primary cardiac cells infected by the T. cruzi, here called T. cruzi fibrotic cardiac microtissue (TCFCM). We also showed that the treatment of TCFCM with a TGF-ß pathway inhibitor reduces fibrosis. Here, we aimed to evaluate the effect of POS in TCFCM, observing parasite load and molecules involved in fibrosis. To choose the concentration of POS to be used in TCFCM we first performed experiments in a monolayer of primary cardiac cell cultures and, based on the results, TCFCM was treated with 5 nM of POS for 96 h, starting at 144 h post-infection. Our previous studies showed that at this time the TCFCM had established fibrosis, resulting from T. cruzi infection. Treatment with POS of TCFCM reduced 50 % of parasite load as observed by real-time PCR and reduced markedly the fibrosis as observed by western blot and immunofluorescence, associated with a strong reduction in the expression of fibronectin and laminin (45 % and 54 %, respectively). POS treatment also changed the expression of proteins involved in the regulation of extracellular matrix proteins (TGF-ß and TIMP-4, increased by 50 % and decreased by 58 %, respectively) in TCFCM. In conclusion, POS presented a potent trypanocidal effect both in 2D and in TCFCM, and the reduction of the parasite load was associated with a reduction of fibrosis in the absence of external immunological effectors.
Assuntos
Cardiomiopatia Chagásica/tratamento farmacológico , Fibrose Endomiocárdica/tratamento farmacológico , Miócitos Cardíacos/efeitos dos fármacos , Triazóis/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Técnicas de Cultura de Células , Cardiomiopatia Chagásica/genética , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/patologia , Fibrose Endomiocárdica/genética , Fibrose Endomiocárdica/parasitologia , Fibrose Endomiocárdica/patologia , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Feto , Fibronectinas/genética , Fibronectinas/metabolismo , Regulação da Expressão Gênica , Humanos , Concentração Inibidora 50 , Laminina/genética , Laminina/metabolismo , Camundongos , Modelos Biológicos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/parasitologia , Carga Parasitária , Cultura Primária de Células , Inibidores Teciduais de Metaloproteinases/genética , Inibidores Teciduais de Metaloproteinases/metabolismo , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/patogenicidade , Inibidor Tecidual 4 de MetaloproteinaseRESUMO
Será descrito a base fisiológica dos componentes da barreira hematoencefálica e suas propriedades. Além disto, pretende-se abordar o efeito particular das metaloproteinases e seu controle sobre as propriedades da matriz extracelular e a relação disto com disfunção da barreira hemotoencefálica. Finalmente se demonstrará o papel da metaloproteinases nas alterações do sistema nervoso central em doenças associadas ao paciente criticamente enfermo.
This paper aims to describe the physiological basis of the blood-brain barrier components and its properties. Additionally, the particular effects of metalloproteinases and their control over the extracellular matrix and its relationship with blood-brain barrier dysfunction are discussed. Finally, the role of metalloproteinases on changes in the central nervous system in critically ill patients is discussed.