RESUMEN
Biological scaffolds have become an attractive approach for repairing the infarcted myocardium and have been shown to facilitate constructive remodeling in injured tissues. This study aimed to investigate the possible utilization of bacterial cellulose (BC) membrane patches containing cocultured cells to limit myocardial postinfarction pathology. Myocardial infarction (MI) was induced by ligating the left anterior descending coronary artery in 45 Wistar rats, and patches with or without cells were attached to the hearts. After one week, the animals underwent echocardiography to assess for ejection fraction and left ventricular end-diastolic and end-systolic volumes. Following patch formation, the cocultured cells retained viability of >90% over 14 days in culture. The patch was applied to the myocardial surface of the infarcted area after staying 14 days in culture. Interestingly, the BC membrane without cellular treatment showed higher preservation of cardiac dimensions; however, we did not observe improvement in the left ventricular ejection fraction of this group compared to coculture-treated membranes. Our results demonstrated an important role for BC in supporting cells known to produce cardioprotective soluble factors and may thus provide effective future therapeutic outcomes for patients suffering from ischemic heart disease.
Asunto(s)
Tratamiento Basado en Trasplante de Células y Tejidos , Celulosa/metabolismo , Infarto del Miocardio/terapia , Función Ventricular Izquierda/fisiología , Animales , Tratamiento Basado en Trasplante de Células y Tejidos/métodos , Corazón/fisiopatología , Miocardio/metabolismo , Neovascularización Fisiológica , Ratas Wistar , Volumen Sistólico/fisiología , Remodelación Ventricular/fisiologíaRESUMEN
Reconstituted cellulose films were generated using residual bacterial cellulose membranes mechanically defibrillated (RBC fibrils) recycled following wound dressing production via a dry-cast process. Arabinogalactan (AG) extracted from Pereskia aculeata leaves and/or a xyloglucan (GHXG) from Guibourtia hymenifolia seeds were incorporating into the RBC at various compositions, and new films were created using the same process. Biocomposite properties were evaluated by scanning electron microscopy, contact angle (CA), and X-ray diffraction measurements. The attachment and proliferation of murine L929 fibroblasts on RBC and RBC/Hydrocolloids (HD) were also evaluated. RBC films with 20-30% GHXG replacement improved film stability and the inclusion of HD increased microfiber aggregation and reduced porous regions. Changes in the hydrophilic characteristics were also observed and owing to the adhesion effect the inclusion of HD on RBC led to a statistically significant effect of the mechanical properties of films. The RBC/AG films supported L929 adhesion similar to that observed for commercial bacterial cellulose, indicating their potential use for biomedical applications.
Asunto(s)
Vendajes/microbiología , Celulosa/química , Celulosa/farmacología , Fenómenos Químicos , Galactanos/química , Glucanos/química , Xilanos/química , Animales , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Adhesión Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Membranas Artificiales , RatonesRESUMEN
Mixtures of gellan gum (GL) and a xyloglucan (XGJ) extracted from Hymenaea courbaril seeds were prepared in a solution of 0.15 mol L(-1) NaCl. Rheology measurements revealed that 2.4 g L(-1) pure GL formed a brittle hydrogel, and GL-XGJ blends showed improved pseudoplastic character with higher XGJ contents. SAXS analyses showed that the Rg dimensions ranged from 1.3 to 4.9 nm, with larger values occurring as the amount of XGJ increased, and diffusion tests indicated that better diffusion of methylene blue dye was obtained in the network with a higher XGJ content. AFM topographic images of the films deposited onto mica revealed fewer heterogeneous surfaces with increased XGJ contents. The water contact angle revealed more hydrophobic character on all of the films, and the wettability decreased with increasing amounts of XGJ. Therefore, the demonstrated benefit of using XGJ blends is the production of a soft material with improved interface properties.
Asunto(s)
Glucanos/aislamiento & purificación , Hidrogeles/aislamiento & purificación , Nanotecnología/métodos , Polisacáridos Bacterianos/aislamiento & purificación , Xilanos/aislamiento & purificación , Glucanos/química , Hidrogeles/química , Hymenaea , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Polisacáridos Bacterianos/química , Difracción de Rayos X , Xilanos/químicaRESUMEN
We describe the mechanical defibrillation of bacterial cellulose (BC) followed by the dry-cast generation of reconstituted BC films (RBC). Xyloglucan (XGT), extracted from tamarind seeds, was incorporated into the defibrillated cellulose at various compositions, and new films were created using the same process. Microscopy and contact angle analyses of films revealed an increase in the microfibre adhesion, a reduced polydispersity in the diameters of the microfibrils and increased hydrophobic behaviour as a function of %XGT. X-ray diffraction analysis revealed changes to the crystallographic planes of the RBC and the biocomposite films with preferential orientation along the (110) plane. Compared with BC, RBC/XGT biocomposite with 10% XGT exhibited improvement in its thermal properties and in Young's modulus. These results indicated a reorganisation of the microfibres with mechanical treatment, which when combined with hydrocolloids, can create cellulose-based materials that could be applied as scaffolding for tissue engineering and drug release.