Hydrogels as scaffolds and delivery systems to enhance axonal regeneration after injuries

This sounds extremely useful for us. Ask your doctor when they are starting human clinical trials. You do expect to know whether this works or not by the time your grandchildren have strokes, don't you? If YOU don't start making a fuss right now you can kiss your grandchildrens' stroke recovery goodbye. Pay it forward!!!
http://journal.frontiersin.org/article/10.3389/fncel.2015.00013/full?utm_source=newsletter&utm_medium=email&utm_campaign=Neuroscience-w14-2015
Damage caused to neural tissue by disease or injury frequently produces a discontinuity in the nervous system (NS). Such damage generates diverse alterations that are commonly permanent, due to the limited regeneration capacity of the adult NS, particularly the Central Nervous System (CNS). The cellular reaction to noxious stimulus leads to several events such as the formation of glial and fibrous scars, which inhibit axonal regeneration in both the CNS and the Peripheral Nervous System (PNS). Although in the PNS there is some degree of nerve regeneration, it is common that the growing axons reinnervate incorrect areas, causing mismatches. Providing a permissive substrate for axonal regeneration in combination with delivery systems for the release of molecules, which enhances axonal growth, could increase regeneration and the recovery of functions in the CNS or the PNS. Currently, there are no effective vehicles to supply growth factors or cells to the damaged/diseased NS. Hydrogels are polymers that are biodegradable, biocompatible and have the capacity to deliver a large range of molecules in situ. The inclusion of cultured neural cells into hydrogels forming three-dimensional structures allows the formation of synapses and neuronal survival. There is also evidence showing that hydrogels constitute an amenable substrate for axonal growth of endogenous or grafted cells, overcoming the presence of axonal regeneration inhibitory molecules, in both the CNS and PNS. Recent experiments suggest that hydrogels can carry and deliver several proteins relevant for improving neuronal survival and axonal growth. Although the use of hydrogels is appealing, its effectiveness is still a matter of discussion, and more results are needed to achieve consistent recovery using different parameters. This review also discusses areas of opportunity where hydrogels can be applied, in order to promote axonal regeneration of the NS.

Introduction

The nervous system (NS) is responsible for the interaction between organisms and their environment; it confers the ability to respond to external stimuli. However, when an injury occurs in this system, such ability is impaired. Understanding fundamental mechanisms involved in the response to damage might be used to design therapeutic interventions aimed to promote functional recovery. Axonal regeneration capacity is very limited in the Central Nervous System (CNS; Gurgo et al., 2002; Case and Tessier-Lavigne, 2005). Although the Peripheral Nervous System (PNS) is able to grow axons after a nerve injury, the lost function is not always restored, because the regenerated axons are unable to reinnervate areas previously connected by them (Johnson et al., 2005). This review describes first the elements that impede axonal regeneration following injury in CNS and PNS, and later discuss how hydrogels might attenuate the inhibitory elements for axonal regeneration in both systems.