Treatment of a burn animal model with functionalized tridimensional electrospun biomaterials.

Laminin-functionalized poly-d,l-lactic acid scaffolds were produced. Following this, mesenchymal stem cells and keratinocytes were seeded on biomaterials for the in vivo experiments, where the biomaterials with or without cells were implanted. The analysis is comprised of the visual aspect and mean size of the lesion plus the histology and gene expression. The results showed that the cells occupied all the structure of the scaffolds in all the groups. After nine days of in vivo experiments, the defect size did not show statistical difference among the groups, although the groups with the poly-d,l-lactic acid/Lam biomaterial had the lowest lesion size and presented the best visual aspect of the wound. Gene expression analysis showed considerable increase of tumor growth factor beta 1 expression, increased vascular endothelial growth factor and balance of the BAX/Bcl-2 ratio when compared to the lesion group. Histological analysis showed well-formed tissue in the groups where the biomaterials and biomaterials plus cells were used. In some animals, in which biomaterials and cells were used, the epidermis was formed throughout the length of the wound. In conclusion, these biomaterials were found to be capable of providing support for the growth of cells and stimulated the healing of the skin, which was improved by the use of cells.

Polylaminin, a polymeric form of laminin, promotes regeneration after spinal cord injury.

Regeneration of spinal cord injury (SCI) is a major topic of biomedical research. Laminin is an extracellular matrix protein implicated in neural development and regeneration, but despite that, there are no reports of exogenous laminin contributing to improve the outcome of experimental SCI. Here we investigated whether a biomimetic polymer of laminin assembled on pH acidification, henceforth called polylaminin, could be used to treat SCI in rats. Acute local injection of polylaminin, but not of nonpolymerized laminin, improved motor function after thoracic compression, partial or complete transection. In the latter case, the BBB score for open field locomotion 8 wk after lesion increased from 4.2 ± 0.48 to 8.8 ± 1.14 in animals treated with polylaminin of human origin. Accordingly, neurons retrogradely labeled from the sublesion stump were detected in the spinal cord and brain stem, indicating regrowth of short and long fibers across a complete transection. Polylaminin also played an unsuspected anti-inflammatory role, which underlies the early onset of its positive effects on locomotion from the first week after treatment. The beneficial effects of polylaminin were not observed in animals treated with the nonpolymerized protein or vehicle only. We propose that polylaminin is a promising therapeutic agent to treat human SCI.

Regeneración tisular guiada en periodoncia. Segunda parte: acondicionadores radiculares / Guided tissue regeneration in periodontics. Second part: root conditioning

El tratamiento de la enfermedad periodontal por los métodos tradicionales, da como resultado una cicatrización por medio de adherencia larga. La meta de la terapia periodontal es regenerar los tejidos de soporte perdidos por el proceso de la enfermedad periodontal inflamatoria. Se han hecho esfuerzos por lograr esta meta usando barreras físicas, reabsorbibles y no reabsorbibles, para impedir la migración epitelial y tratando la superficie radicular con varios agentes: acondicionadores radiculares y factores de crecimiento. Las investigaciones recientes se han enfocado a la regeneración del periodonto, intentando definir los factores involucrados en la formación de nueva inserción de tejido conectivo a la superficie radicular denudada por la enfermedad periodontal. Después de la adhesión celular al sustrato, uno de los eventos biológicos involucrados en la regeneración tisular es la migración celular dirigida específicamente o quimiotaxis, la cual es la característica principal de muchos procesos biológicos en salud y enfermedad. Esos eventos celulares son influenciados y regulados por factores de crecimiento. Para entender el papel regulador de estos factores en la cicatrización periodontal, es importante caracterizar su influencia involucrada en los eventos celulares críticos en el proceso de cicatrización. Los factores de crecimiento estudiados y que han demostrado repetidamente su papel en estos procesos de cicatrización son: el factor de crecimiento beta transformante, el derivado de las plaquetas, el similar a la insulina y el básico del fibroblasto. También son importantes como acondicionadores radiculares las siguientes sustancias: la tetraciclina, el ácido cítrico, la fibronectina y la laminina