CESAR ISAAC
Projetos de Pesquisa
Unidades Organizacionais
LIM/04 - Laboratório de Microcirurgia, Hospital das Clínicas, Faculdade de Medicina - Líder
2 resultados
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- Human fetal wound healing: a review of molecular and cellular aspects(2016) YAGI, Leticia Hitomi; WATANUKI, Larissa Martins; ISAAC, Cesar; GEMPERLI, Rolf; NAKAMURA, Yeda Midori; LADEIRA, Pedro Ribeiro SoaresThe physiological answer to after birth skin lesions is scarring, which compromises the function and the aesthetics of the injured area. However, fetuses in early gestation (24 weeks or less) respond to this damage with skin regeneration. To explain this difference, several factors are considered, such as increased production of collagen III in fetal fibroblasts and increased presence of this collagen in the skins of these fetuses. Increased hyaluronic acid in fetal matrix correlates with greater capacity for migration of fibroblasts in scarless repair. The fact that myofibroblasts in the wound appear only after the fetal stage of pregnancy which forms scars can also be correlated. Additionally, there is an increase in the amount of adhesion molecules in repair without scarring, which would multiply cell adhesion and migration. Lower levels of bTGF1 in fetal wound are correlated with reduced amounts of collagen I and may be the result of higher relative expression of bTGF3, which downregulates bTGF1. Amniotic fluid itself might be a stimulating factor to human skin's fibroblasts proliferation through cytokines such as bFGF and PDGF. A hypoxic environment in the fetal wound, associated with increased presence of Dot cells in blood, is also observed, and both facts can be related to a difference in the repair of the skin. Distinct gene expression guides those different responses and may also help to elucidate fetal skin regeneration. When the mechanisms responsible for the absence of scars in wounded fetuses are enlightened, it will be a significant mark in the studies of wound cicatrization and its therapeutic applications shall be extremely valuable.
- COMPARISONS OF THE RESULTS OF PERIPHERAL NERVE DEFECT REPAIR WITH FIBRIN CONDUIT AND AUTOLOGOUS NERVE GRAFT: AN EXPERIMENTAL STUDY IN RATS(2016) LONGO, Marco Vinicius Losso; FARIA, Jose Carlos Marques De; ISAAC, Cesar; NEPOMUCENO, Andre Coelho; TEIXEIRA, Nuberto Hopfgartner; GEMPERLI, RolfIntroduction: The standard treatment for nerve defects is nerve autograft. There is no conduit available that provides the same regenerative capacity of nerve autograft. This study evaluated the histological and functional recovery of nerve defects treated with fibrin conduit in comparison to the nerve autograft, in a rat model. Method: A sciatic nerve injury model (10-mm defect) was performed in 20 Wistar rats, nerve defect was reconstructed using a fibrin conduit (n=10). A nerve autograft was used as control (n=10). The walking behavior was measured by footprint analysis at 4, 8, and 12 weeks and sciatic function index was determined. After 12 weeks, histological analysis was performed to evaluate the regenerated nerve and measured axonal density. The triceps surae muscle weight was also evaluated. Results: The fibrin conduit group showed less improvement in walking behavior compared to nerve autograft (-53 +/- 2 vs. -36 +/- 2; P<0.001 at 12 weeks). The fibrin conduit group presented axonal density of 40.0 axons/10.995 mu m2 and the nerve autograft group had 67.2 axons/10.995 mu m2 (P<0.001). The triceps surae muscle weight ratio of the fibrin conduit group was 41 +/- 3% versus 71 +/- 4% of the nerve autograft group (P<0.001). Conclusion: The fibrin conduit could be used for nerve reconstruction following peripheral nerve injury in the rat model. However, the functional recovery in the fibrin conduit repair group was worse than that in nerve autograft group and the nerve repair with the fibrin conduit has less myelinated fibers when compared to the repair with nerve autograft. (C) 2015 Wiley Periodicals, Inc.