Nervous
system diseases (such as Parkinson’s or post-traumatic medullar injury)
are especially difficult to treat, as it is not easy to replace the
parts of the neural puzzle which are damaged. The key is in developing
functional neurons from in vitro-treated, cells but for this it is
essential that the support on which these cells are based simulate the
characteristics of 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”.
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, among other things, be guided and acquire
neuronal functionality, enabling the formation of new transplantable
tissue for the nervous system. 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
neurones 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 neurones, in
the best of cases). 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, García carried out trials with cells from the
hippocampus 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 neurones 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
neurones 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 neurones
been obtained.