RAFAEL SIMAS
Projetos de Pesquisa
Unidades Organizacionais
LIM/11 - Laboratório de Cirurgia Cardiovascular e Fisiopatologia da Circulação, Hospital das Clínicas, Faculdade de Medicina
6 resultados
Resultados de Busca
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- Bilateral sympathectomy improves postinfarction left ventricular remodeling and function(2017) ZANONI, Fernando Luiz; SIMAS, Rafael; SILVA, Raphael Grillo da; BREITHAUPT-FALOPPA, Ana Cristina; SILVA, Raphael dos Santos Coutinho e; JATENE, Fabio Biscegli; MOREIRA, Luiz Felipe P.Objectives: To evaluate the influence of bilateral or left sympathectomy on left ventricular remodeling and function after myocardial infarction in rats. Methods: Myocardial infarction was induced in rats by ligation of the left anterior descending coronary. Seven days later, rats were divided into 4 groups: the myocardial infarction, myocardial infarction with left sympathectomy, myocardial infarction with bilateral sympathectomy, and sham groups. After 8 weeks, left ventricular function was evaluated with the use of a pressure-volume conductance catheter under steady-state conditions and pharmacological stress. Infarct size and extracellular matrix fibrosis were evaluated, and cardiac matrix metalloproteinases and myocardial inflammatory markers were analyzed. Results: The myocardial infarction and left sympathectomy group had an increased end diastolic volume, whereas the bilateral sympathectomy group had a mean end-diastolic volume similar to that of the sham group (P <. 002). Significant reduction in ejection fraction was observed in the myocardial infarction and left sympathectomy group, whereas it was preserved after bilateral sympathectomy (P < .001). In response to dobutamine, left ventricular contractility increased in sham rats, rising stroke work, cardiac output, systolic volume, end-diastolic volume, ejection fraction, and dP/dt max. Only bilateral sympathectomy rats had significant increases in ejection fraction (P <. 001) with dobutamine. Fibrotic tissue and matrix metalloproteinase expression decreased in the bilateral sympathectomy group compared to that in the myocardial infarction group (P <. 001) and was associated with left ventricular wall thickness maintenance and better apoptotic markers in noninfarcted myocardium. Conclusions: Bilateral sympathectomy effectively attenuated left ventricular remodeling and preserved systolic function after myocardial infarction induction in rats.
- Acute administration of oestradiol or progesterone in a spinal cord ischaemia-reperfusion model in rats(2018) CAVALCANTE, Leonardo Pessoa; FERREIRA, Sueli Gomes; PEREIRA, Daniel Romano; MORAES, Sergio Rodrigues de; SIMAS, Rafael; SANNOMIYA, Paulina; BREITHAUPT-FALOPPA, Ana Cristina; MOREIRA, Luiz Felipe PinhoOBJECTIVES: Despite research into protective pharmacological adjuncts, paraplegia persists as a dreaded complication after thoracic and thoracoabdominal aortic interventions. Reports on gender-related neurological outcomes after ischaemic and traumatic brain injuries have led to increased interest in hormonal neuroprotective effects and have generated other studies seeking to prove the neuroprotective effects of the therapeutic administration of 17 beta-oestradiol and of progesterone. We hypothesised that acute administration of oestradiol or progesterone would prevent or attenuate spinal cord ischaemic injury induced by occlusion of the descending thoracic aorta. METHODS: Male rats were divided into groups receiving 280 A mu g/kg of 17 beta-oestradiol or 4 mg/kg of progesterone or vehicle 30 min before transitory endovascular occlusion of the proximal descending thoracic aorta for 12 min. Hindlimb motor function was assessed by a functional grading scale (that of Basso, Beattie and Bresnahan) for 14 days after reperfusion. On the 14th day, a segment of the thoracolumbar spinal cord was harvested and prepared for histological and immunohistochemical analyses. RESULTS: There was significant impairment of the motor function of the hindlimb in the 3 study groups, with partial improvement noticed over time, but no difference was detected between the groups. On Day 1 of assessment, the 17 beta-oestradiol group had a functional score of 9.8 (0.0-16.5); the progesterone group, a score of 0.0 (0-17.1) and the control group, a score of 6.5 (0-16.9); on the 14th day, the 17 beta-oestradiol group had a functional score of 18.0 (4.4-19.4); the progesterone group had a score of 7.5 (0-18.5) and the control group had a score of 17.0 (0-19.9). Analysis of the grey matter showed that the number of viable neurons per section was not different between the study groups on the 14th day. Immunostaining of the spinal cord grey matter was also similar among the 3 groups. CONCLUSIONS: Acute administration of oestradiol or of progesterone 30 min before transitory occlusion of the proximal descending thoracic aorta of male rats could not prevent or attenuate spinal cord ischaemic injury based on an analysis of functional and histological outcomes.
conferenceObject EFFECTS OF HYPERTONIC SALINE SOLUTION ON CARDIAC AND PULMONARY CHANGES AFTER BRAIN DEATH: AN EXPERIMENTAL STUDY(2017) CORREIA, Cristiano; MAGGALHAES, Daniel M.; ZANONI, Fernando; SIMAS, Rafael; SOARES, Rafaela Garcia Ferreira; SILVA, Raphael S. Coutinho E; BREITHAUPT-FALOPPA, Ana Cristina; SANNOMIYA, Paulina; MOREIRA, Luiz Felipe- Effect of bilateral sympathectomy in a rat model of dilated cardiomyopathy induced by doxorubicin(2020) SILVA, Raphael dos Santos Coutinho e; ZANONI, Fernando Luiz; SIMAS, Rafael; SILVA, Mateus Henrique Fernandes Martins da; ARMSTRONG JUNIOR, Roberto; CORREIA, Cristiano de Jesus; FALOPPA, Ana Cristina Breithaupt; MOREIRA, Luiz Felipe PinhoObjective: The study objective was to evaluate the effect of bilateral sympathectomy on ventricular remodeling and function in a rat model of dilated cardiomyopathy induced by doxorubicin. Methods: Dilated cardiomyopathy was induced in male Wistar rats by weekly intraperitoneal injection of doxorubicin (2 mg/kg) for 9 weeks. Animals were divided into 4 groups: dilated cardiomyopathy; bilateral sympathectomy, submitted on day 15 of the protocol to bilateral sympathectomy; angiotensin-converting enzyme inhibitor, treated with enalapril through day 15 until the end of the experimental protocol; and sham, nonsubmitted through doxorubicin protocol, with weekly intraperitoneal injections of saline solution (0.9%). The left ventricular function was assessed, and the heart was collected for posterior analyses. Results: The dilated cardiomyopathy group presented a significant decrease in the myocardial efficiency when compared with the sham group (33.4% vs 71.2%). Only the bilateral sympathectomy group was able to preserve it (57.5%; P = .0001). A significant dilatation in the left ventricular chamber was observed in the dilated cardiomyopathy group (15.9 mu m(2)) compared with the sham group (10.2 mu m(2); P = .0053). Sympathectomy and enalapril prevented ventricular remodeling (9.5 and 9.6 mu m(2), respectively; P = .0034). There was a significant increase in interstitial myocardial fibrosis in the dilated cardiomyopathy group (14.8%) when compared with the sham group (2.4%; P = .0001). This process was significantly reduced with sympathectomy and enalapril (8.7 and 3.9%, respectively; P = .0001). Conclusions: Bilateral sympathectomy was effective in preventing remodeling and left ventricular dysfunction in a rat model of dilated cardiomyopathy induced by doxorubicin.
- HYPERTONIC SALINE SOLUTION REDUCES MICROCIRCULATORY DYSFUNCTION AND INFLAMMATION IN A RAT MODEL OF BRAIN DEATH(2019) CORREIA, Cristiano de Jesus; ARMSTRONG JR., Roberto; CARVALHO, Priscila Oliveira de; SIMAS, Rafael; SANCHEZ, Daniela Crisina Janolli; BREITHAUPT-FALOPPA, Ana Cristina; SANNOMIYA, Paulina; MOREIRA, Luiz Felipe PinhoBackground: Brain death (BD) induces hemodynamic instability with microcirculatory hypoperfusion, leading to increased organ inflammation and dysfunction. This study investigated the effects of 7.5% hypertonic saline solution (HSS) on mesenteric microcirculatory dysfunction and inflammation in a rat model of BD. Methods: Male Wistar rats were anesthetized and mechanically ventilated. BD was induced by rapidly inflating an intracranial balloon catheter. The rats were randomly divided into: SH, sham-operated rats subjected to trepanation; NS, rats treated with NaCl 0.9%, 4 mL/kg immediately after BD; T-1, rats treated with HSS (NaCl 7.5%, 4 mL/kg) immediately or 60 min after BD, T-60. All groups were analyzed 180 min after the start of the experiment. Results: Rats in BD groups presented with a similar hypertensive peak, followed by hypotension. Proportion of perfused small vessels was decreased in the NS group (46%) compared with the SH group (74%, P = 0.0039). HSS restored the proportion of perfused vessels (T-1 = 71%, P = 0.0018). The anti-endothelial nitric oxide synthase (eNOS) protein expression significantly increased in rats given HSS (T-1, and T-60, P = 0.0002). Similar results were observed regarding endothelin-1 (P<0.0001). Increased numbers of rolling (P = 0.0015) and migrated (P = 0.0063) leukocytes were observed in the NS group compared with the SH group. Rats given HSS demonstrated an overall reduction in leukocyte-endothelial interactions. The ICAM-1 levels increased in the NS group compared with the SH group, and decreased in the HSS-treated groups (P = 0.0002). Conclusions: HSS may improve the density of mesenteric perfused small vessels due to its effects on eNOS and endothelin-1 protein expression, and reduces inflammation by decreasing leukocyte adhesion and migration in a rat model of BD.
conferenceObject HYPERTONIC SALINE SOLUTION REDUCES INFLAMMATION IN RATS SUBMITTED TO BRAIN DEATH: AN INTRAVITAL MICROSCOPIC STUDY(2015) CORREIA, Cristiano De Jesus; JANOLLI, Daniele; ARMSTRONG JR., Roberto; SIMAS, Rafael; BREITHAUPT-FALOPPA, Ana Cristina; SANNOMIYA, Paulina; MOREIRA, Luiz Felipe