ALESSANDRO RODRIGO BELON
Projetos de Pesquisa
Unidades Organizacionais
LIM/26 - Laboratório de Pesquisa em Cirurgia Experimental, Hospital das Clínicas, Faculdade de Medicina
5 resultados
Resultados de Busca
Agora exibindo 1 - 5 de 5
- Impact of Three Methods of Ischemic Preconditioning on Ischemia-Reperfusion Injury in a Pig Model of Liver Transplantation(2022) BELON, Alessandro Rodrigo; TANNURI, Ana Cristina Aoun; MOREIRA, Daniel de Albuquerque Rangel; FIGUEIREDO, Jose Luiz; SILVA, Alessandra Matheus da; SERAFINI, Suellen; GUIMARAES, Raimundo Renato; FARIA, Caroline Silverio; ALEXANDRE, Alcione Sanches de; GONCALVES, Josiane Oliveira; PAES, Vitor Ribeiro; TANNURI, UenisBackground Ischemic preconditioning (IPC), either direct (DIPC) or remote (RIPC), is a procedure aimed at reducing the harmful effects of ischemia-reperfusion (I/R) injury. Objectives To assess the local and systemic effects of DIPC, RIPC, and both combined, in the pig liver transplant model. Materials and methods Twenty-four pigs underwent orthotopic liver transplantation and were divided into 4 groups: control, direct donor preconditioning, indirect preconditioning at the recipient, and direct donor with indirect recipient preconditioning. The recorded parameters were: donor and recipient weight, graft-to-recipient weight ratio (GRWR), surgery time, warm and cold ischemia time, and intraoperative hemodynamic values. Blood samples were collected before native liver removal (BL) and at 0 h, 1 h, 3 h, 6 h, 12 h, 18 h, and 24 h post-reperfusion for the biochemical tests: aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), creatinine, BUN (blood urea nitrogen), lactate, total and direct bilirubin. Histopathological examination of liver, gut, kidney, and lung fragments were performed, as well as molecular analyses for expression of the apoptosis-related BAX (pro-apoptotic) and Bcl-XL (anti-apoptotic) genes, eNOS (endothelial nitric oxide synthase) gene, and IL-6 gene related to inflammatory ischemia-reperfusion injury, using real-time polymerase chain reaction (RT-PCR). Results There were no differences between the groups regarding biochemical and histopathological parameters. We found a reduced ratio between the expression of the BAX gene and Bcl-XL in the livers of animals with IPC versus the control group. Conclusions DIPC, RIPC or a combination of both, produce beneficial effects at the molecular level without biochemical or histological changes.
- Assessing ultrasonographic optic nerve sheath diameter in animal model with anesthesia regimens(2022) AZEVEDO, Maira de Robertis; DE-LIMA-OLIVEIRA, Marcelo; BELON, Alessandro Rodrigo; BRASIL, Sergio; TEIXEIRA, Manoel Jacobsen; PAIVA, Wellingson Silva; BOR-SENG-SHU, EdsonPurpose: To determine the normal optical nerve sheath (ONS) diameter ultrasonography (ONSUS) and evaluate the possible effects of drugs on ONS diameter during anesthetic induction in healthy pigs. Methods: Healthy piglets were divided into three groups: a control group, that received xylazine and ketamine (X/K); other that received xylazine, ketamine and propofol (X/K/P); and a third group that received xylazine, ketamine, and thiopental (X/K/T). The sheath diameter was assessed by ultrasonography calculating the average of three measurements of each eye from the left and right sides. Results: 118 animals were anesthetized (49 X/K 33 X/K/P and 39 X/K/T). Mean ONS sizes on both sides in each group were 0.394 +/- 0.048 (X/K), 0.407 +/- 0.029 (X/K/P) and 0.378 +/- 0.042 cm (X/K/T) (medians of 0.400, 0.405 and 0.389, respectively). The ONS diameter varied from 0.287-0.512 cm (mean of 0.302 +/- 0.039 cm). For group X/K, the mean diameter was 0.394 +/- 0.048 cm. Significant differences in ONS sizes between the groups P and T (X/K/P > X/K/T, p = 0.003) were found. No statistically significant differences were detected when other groups were compared (X/K = X/K/P, p = 0.302; X/K = X/K/T, p = 0.294). Conclusion: Sedation with thiopental lead to significative ONS diameter reduction in comparison with propofol. ONSUS may be useful to evaluate responses to thiopental administration.
- Large-for-size liver transplantation: a flowmetry study in pigs(2014) MOREIRA, Daniel de Albuquerque Rangel; TANNURI, Ana Cristina Aoun; BELON, Alessandro Rodrigo; COELHO, Maria Cecilia Mendonca; GONCALVES, Josiane Oliveira; SERAFINI, Suellen; LIMA, Fabiana Roberto; AGOSTINI, Luciana Orsi; GUIMARAES, Raimundo Renato; TANNURI, UenisBackground: Ischemia-reperfusion injury is partly responsible for morbidity in pediatric liver transplantation. Large-for-size (LFS) liver transplantation has not been fully studied in the pediatric population, and the effects of reperfusion injury may be underestimated. Materials and methods: Thirteen Landrace-Large white pigs weighing 23 kg (range, 17-38 kg) underwent orthotopic liver transplantation. They were divided into two groups according to the size of the donor body: LFS and control (CTRL). After transplantation, the abdominal cavity of the recipient was kept open and portal venous flow (PVF) was measured after 1 h. The ratio of recipient PVF (PVFr) to donor PVF was used to establish correlations with ischemia and reperfusion parameters. Liver biopsies were taken 1 h after transplantation to assess ischemia and reperfusion and to quantify the gene expression of endothelial nitric oxide synthase, interleukin 6, BAX, and BCL. Results: Recipient weight, total ischemia time, and warm ischemia time were similar between groups. Among hemodynamic and metabolic analyses, pH, central arteriovenous PCO2 difference, and AST were statistically worse in the LFS group than in the CTRL group. The same was found with endothelial nitric oxide synthase (0.41 +/- 0.18 versus 1.56 +/- 0.78; P = 0.02) and interleukin 6 (4.66 +/- 4.61 versus 16.21 +/- 8.25; P = 0.02). In the LFS group, a significant decay in the PVFr was observed in comparison with the CTRL group (0.93 +/- 0.08 and 0.52 +/- 0.11, respectively; P < 0.001). Conclusions: The implantation of a graft was responsible for poor hemodynamic status of the recipient 1 h after transplantation. Furthermore, the LFS group demonstrated markers of ischemia and reperfusion that were worse when compared with the CTRL group and exhibited a more significant decrease in PVF from donor to recipient.
- Does Arterialization of Portal Vein Have Any Effects in Large-for-Size Liver Transplantation? Hemodynamic, Histological, and Biomolecular Experimental Studies(2022) TORRES, Rafael Rodrigues; TANNURI, Ana Cristina Aoun; SERAFINI, Suellen; BELON, Alessandro; GONCALVES, Josiane Oliveira; LORETO, Celso di; TANNURI, UenisBackground: In pediatric liver transplantation, the optimal size of the transplanted liver ranges between 0.8% and 4.0% of the recipient's weight. Sometimes, the graft weight exceeds this upper limit, characterizing the large-for-size condition potentially associated with reduced blood flow and worsening of ischemia-reperfusion injury. Therefore, it would be beneficial to increase the portal flow through arterialization of the portal vein. Materials and methods: Fifteen pigs underwent large-for-size liver transplants. They were divided into two groups: control (CTRL 6 animals - conventional technique) and arterialization - a shunt was established between the portal vein and the splenic artery (ART 9 animals). Hemodynamic, biochemical, histological, and molecular variables were compared. Results: Arterialization resulted in a significant increase in portal vein pressure but no changes in other hemodynamic variables, as shown in the analysis of variance. It was observed lower ALT values (p = 0.007), with no differences regarding the values of blood pH and lactate (p = 0.54 and p = 0.699 respectively) or histological variables (edema, steatosis, inflammation, necrosis, and IRI - p = 1.0, p = 0.943, p = 0.174, p = 0.832, p = 0.662, respectively). The molecular studies showed significantly increased expression of IL6 after 3 hours of reperfusion (p = 0.048) and decreased expression of ICAM immediately after reperfusion (p = 0.03). The regression analysis suggested a positive influence of portal flow and pressure on biochemical parameters. Conclusion: Arterialization of the portal vein showed no histological, biochemical, or molecular benefits in large-for-size transplantation.
- Pentoxifylline associated to hypertonic saline solution attenuates inflammatory process and apoptosis after intestinal ischemia/reperfusion in rats(2014) MARQUES, Geraldo Magela Nogueira; RASSLAN, Roberto; BELON, Alessandro Rodrigo; CARVALHO, Juliana Gonalves; NETO, Raphael Felice; RASSLAN, Samir; UTIYAMA, Edivaldo Massazo; MONTERO, Edna Frasson de SouzaPURPOSE: To evaluate intestinal inflammatory and apoptotic processes after intestinal ischemia/reperfusion injury, modulated by pentoxifylline and hypertonic saline. METHODS: It was allocated into four groups (n=6), 24 male Wistar rats (200 to 250g) and submitted to intestinal ischemia for 40 min and reperfusion for 80 min: IR (did not receive any treatment); HS group (Hypertonic Saline, 4ml/kg-IV); PTX group (Pentoxifylline, 30mg/kg-IV); HS+PTX group (Hypertonic Saline and Pentoxifylline). All animals were heparinized (100U/kg). At the end of reperfusion, ileal fragments were removed and stained on hematoxylin-eosin and histochemical studies for COX-2, Bcl-2 and cleaved caspase-3. RESULTS: The values of sO(2) were higher on treated groups at 40 minutes of reperfusion (p=0.0081) and 80 minutes of reperfusion (p=0.0072). Serum lactate values were lower on treated groups after 40 minutes of reperfusion (p=0.0003) and 80 minutes of reperfusion (p=0.0098). Morphologic tissue injuries showed higher grades on IR group versus other groups: HS (p=0.0006), PTX (p=0.0433) and HS+PTX (p=0.0040). The histochemical study showed lesser expression of COX-2 (p=0.0015) and Bcl-2 (p=0.0012) on HS+PTX group. A lower expression of cleaved caspase-3 was demonstrated in PTX (p=0.0090; PTXvsIR). CONCLUSION: The combined use of pentoxifylline and hypertonic saline offers best results on inflammatory and apoptotic inhibitory aspects after intestinal ischemia/reperfusion.