Conductos de ácido hialurónico para el crecimiento axonal guiado

[EN] Since a considerable number of factors limit or prevent the autonomous regeneration of injured or degenerated tracts in the nervous system, its effective restoration is a rare phenomenon. Therefore, conventional medicine has only succeeded in therapies aimed at treating the symptoms and effects of the damage. In order to revert them and to restore the functionality of a neuronal network, tissue engineering is currently researching about the synergic use of cells, bioactive molecules and three-dimensional biocompatible supports. More precisely, the regeneration of nervous system damaged structures is being studied through strategies like the so-called neural conduits. In this thesis, a channeled porous scaffold based on hyaluronic acid, a hydrophilic natural polymer, has been designed, developed and characterized, both physicochemically and biologically. By chemically crosslinking this polymer through divinyl sulfone and next lyophilizing it, a degradable and millimeter-size conduit has been obtained, soft but stable in physiological medium. The conduit wall has a singular three-layer distribution, able to avoid glial cells migration through it, but entirely permeable to nutrients and proteins. Furthermore, if Schwann cells are cultured for 10 days within the conduit's lumen, they create a cell tube-like structure with several hundreds of microns in diameter, thin but dense, similar to those of nerve fascicles. The ability of the conduits, the Schwann cells macrosheath and a bundle of 30 um poly-L-lactic acid fibers to guide the growth of neurons in dorsal root ganglia explants has been evaluated as well. Only the biohybrid system, composed by the conduit, the stretched fibers within and the cells macrosheath, is a beneficial enough context to permit neurons grow at a similar rate to other promising strategies in tissue engineering of the nervous system. [ES] La regeneración de tractos dañados o degenerados del sistema nervioso de manera autónoma es un fenómeno infrecuente, ya que están implicados una considerable cantidad de factores que la limitan u obstaculizan. Por ello, la medicina convencional tan solo ha logrado limitados éxitos a este respecto, tratando únicamente los síntomas y los efectos del daño. Para intentar revertirlo y lograr la reconexión funcional de neuronas, en la actualidad la ingeniería tisular está investigando acerca de la aplicación sinérgica de células, moléculas bioactivas y soportes tridimensionales biocompatibles. Concretam