A mold on which to create new parts of the puzzle that is the nervous system

This is what biochemist Patricia García has done, developing and validating a polymer support capable of inducing neuronal differentiation in vitro. Her PhD thesis, defended at the University of the Basque Country (UPV/EHU) and undertaken at the Tecnalia Health Unit, is entitled Development of a new polymer support with components of extracellular neural matrix for application in the in vitro differentiation of different primary cells.

Ms García has developed a polymer material which contains topographic and biochemical characteristics suitable for converting cells into functional neurons. With this purpose in mind, photolithographic techniques have been combined with the technology of extracellular neural matrixes. The photolithographic technique involves a series of treatments based on exposure to light and chemical substances, and has acted to provide the support with the desired topographical form. As regards the extracellular neural matrix, cells adhere to this natural substrate in order to, amongst other things, be guided and acquire neuronal functionality, enabling the formation of new transplantable tissue for the nervous system. Ms García simulated the properties of this matrix in the support developed.

Biocompatible and inductor

At the validation phase, this polymer material proved to be biocompatible with the nervous system. It also acts to induce the formation of neurons sufficiently developed to be able to be used therapeutically, providing the induction is carried out from neural origin cells (the trials with non-neural origin cells gave rise to immature neurons, in the best of cases). Ms García undertook validations with the PC12 rat established cell line (used in numerous trials for neuronal differentiation) and with cell cultures of different origins (primary cultures) extracted from rats.

Concretely, in the case of the validations with PC12, the biocompatibility and capacity of neuronal and dopaminergic differentiation (dopamine complies with neurotransmitter functions) of the support developed have been clearly demonstrated.

Only with those of neural origin

As regards primary cultures, Ms García carried out trials with cells from the hypocampus in the embryonic rat. These are cells not only of neural origin but with the neuronal line already determined in states of early development such as the embryonic stage. These cells differentiate more efficiently in the developed matrix than in the classic conditions of culture, obtaining mature neurons after only eight days.

The second primary culture validated in the matrix was the one consisting of neural precursor cells (cells at the stage prior to converting into neurons) of the subventricular zone (also the brain) of the neonatal rat. The results show the capacity of dopaminergic neuronal differentiation in less than 30 days of culture. Moreover, an extensive network of glial cells between the matrix and the neurons were observed, and whose function is to give trophic support to and signal the neurons in development.

The last validation trial in primary culture was undertaken with cells of non-neural origin. These are precursor cells derived from the skin of an adult rat, given that they have been already described in the literature as an important source of neural precursor cells. Nevertheless, in this case, the cells stay undifferentiated on the matrix developed, and only in a low percentage have immature neurons been obtained.