Navegando por Palavras-chave "biomateriais"

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    Biomateriais na reparação do sistema nervoso central: uso de nanofibras sintéticas biodegradáveis como suporte para transplante celular e nanopartículas contendo cxcl12 no recrutamento de células-tronco endógenas
    (Universidade Federal de São Paulo (UNIFESP), 2016-12-31) Zamproni, Laura Nicoleti [UNIFESP]; Porcionatto, Marimelia Porcionatto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Central nervous system (CNS) disorders are highly debilitating and with few therapeutic options. Stem cells are a therapeutic promise for these diseases. The two main strategies described in literature are exogenous stem cells transplantation and enhancement of endogenous neurogenesis. Since both strategies pose problems, there is increasing research on the use of biomaterial to try to optimize cell engraftment and delivery of soluble factors that can increase neurogenesis. In this study, we evaluated polylactic acid (PLA) polymeric nanofibers (PNF) as carriers for cell transplantation and evaluated two formulations of poly(lactic-co-glycolic acid) (PLGA) for local delivery of CXCL12, a powerful chemokine to recruit neural stem cells (NSC). PNF were produced by jet-rotatory spinning and characterized by scanning electron microscopy. MSC and NSC obtained respectively from bone marrow and subventricular zone of C57BL/6 adult mice were cultured on PNF and transplanted into the brain of adult mice submitted to ischemic stroke model. Both cell types were viable when cultured on PNF, and MSC but not NSC were able to reduce the necrotic area. CXCL12 formulations were made by double emulsion. Two formulations were evaluated: microspheres (MS) and nanoparticles (NP). Both were able to encapsulate more than 80% of CXCL12, but showed different release profiles, with 100% CXCL12 released after 6 days for MS and 25% CXCL12 released after 2 weeks for NP. CXCL12 bioactivity was demonstrated by chemotaxis assay. When injected into the brains of mice submitted to traumatic brain injury model, only NP-CXCL12 induced CTN migration to the injured area. We conclude that the PNF are viable scaffolds for cell transplantation, MS and NP are suitable for soluble factor, such as CXCL12, delivery in two different brains injury model. Thus, we suggest that both approaches presented in this work could be tested as therapeutic strategies for CNS injuries.
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    Estudo da cicatrização da parede abdominal de coelhos em modelo experimental de hérnia incisional com a utilização dos biomateriais polipropileno, polipropileno/poliglecaprone e polipropileno/polidioxanona/celulose oxidada regenerada
    (Universidade Federal de São Paulo (UNIFESP), 2013-06-26) Aramayo, Ana Leticia Gomes [UNIFESP]; Lopes Filho, Gaspar de Jesus Lopes Filho [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Introduction: The incisional hernia (IH) is a common complication of abdominal surgery. The use of meshes for possible surgical correction of HI, marked reduction in recurrence of the disease. However, the contact with the viscera of the meshes can be associated with the formation of adhesions and various complications. Purpose: To assess the macro and microscopic healing process of the abdominal wall of rabbits before the repair of incisional hernias using specific biomaterials: Polypropylene (PREMILENE®), Polypropylene / polyglecaprone (ULTRAPRO®), Polypropylene / Polydioxanone / Oxidized Regenerated Cellulose (PROCEED®) Repair without mesh-Transposition peritoneum-aponeurotic bilateral longitudinal (TRANSPALB). Methods: 40 rabbits were operated, with production of incisional hernia. After 30 days, all developed HI and rabbits were reoperated with hernia repair with or without the use of meshes. The animals were randomly assigned: Group 1 (N = 10) - PREMILENE® (PPL): intraperitoneal mesh placed and secured in the posterior wall of the rectus abdominis muscles, group 2 (N = 10) - ULTRAPRO® (UP): intraperitoneal mesh placed and secured in the posterior wall of the rectus abdominis muscles, GROUP 3 (N = 10) - PROCEED® (PCD): intraperitoneal mesh placed and secured in the posterior wall of the rectus abdominis muscles; GROUP 4 (N = 10) - CONTROL GROUP - TRANSPALB (Transpose-peritoneum aponeurotic bilateral longitudinal). After 30 days, the animals were taken to euthanasia being performed macroscopic and microscopic study withdrawal part of the abdominal wall. Results: Macroscopic - Area of adhesions: PPL> UP and PCD (p = 0.031). Vascularization: PPL> UP and PCD (p = 0.001). Adhesion size: (p = 0.134). Type Separation of adhesions: p = 0.083. The total score of adhesions was not statistically significant when comparing the three groups with meshes (p = 0.064). For all animals with meshes there was a reduction of the mesh area. The group PPL showed an average reduction of 40.7% (p = 0.032) and the PCD group of 53% (p <0.001) greater percentage reduction when compared to UP (24.3%). The percentage reduction of meshes PPL group was not statistically significant when compared to the PCD group (p = 0.130). Microscopic - The PCD group had higher neutrophils than groups PPL, UP and TRANSPALB (p = 0.010). The PPL group showed greater eosinophils than groups UP, PCD and TRANSPALB (p = 0.010). The groups PPL and PCD showed increased presence of granulation tissue than the UP and TRANSPALB groups (p<0.001). The groups PPL, UP and PCD showed higher macrophages than TRANSPALB groups (p<0.001). The groups PPL and PCD showed higher lymphocyte presence than the UP group (p = 0.009) and TRANSPALB (p<0.001). The groups PPL, UP and PCD had higher presence of giant cells than TRANSPALB group (p<0.001). The mesothelial reaction (p = 0.061) and fibrosis (p = 0.353) were not statistically significant. The groups PPL and UP exhibited more viscera adhered than PCD and TRANSPALB groups (p<0.001). Conclusions: 1 - All types of meshes used in this study led to the formation of adhesions and the group without mesh showed no adhesions. 2 - The groups ULTRAPRO® and PROCEED® showed lower area of adhesions and lower vascularization of adhesions in relation to the PREMILENE® group. 3 - Comparison of measurements of areas of the meshes, there was a decrease in all meshes, but in the groups PREMILENE® and PROCEED® the decrease was greater. 4 - The inflammatory process both acute and chronic, was higher in groups PREMILENE® and PROCEED®, but there was a predominance of acute inflammatory process in the group PROCEED®.