Neural stem cell
[1] Some neural progenitor stem cells persist in highly restricted regions in the adult vertebrate brain and continue to produce neurons throughout life.
In the adult mammalian brain, the subgranular zone in the hippocampal dentate gyrus, the subventricular zone around the lateral ventricles, and the hypothalamus (precisely in the dorsal α1, α2 region and the hypothalamic proliferative region, located in the adjacent median eminence) have been reported to contain neural stem cells.
[7] In previous studies, cultured neurospheres have been transplanted into the brains of immunodeficient neonatal mice and have shown engraftment, proliferation, and neural differentiation.
These niches provide nourishment, structural support, and protection for the stem cells until they are activated by external stimuli.
The responses during stroke, multiple sclerosis, and Parkinson's disease in animal models and humans is part of the current investigation.
[7] Neural stem cells have been shown to engage in migration and replacement of dying neurons in classical experiments performed by Sanjay Magavi and Jeffrey Macklis.
In addition, Masato Nakafuku's group from Japan showed for the first time the role of hippocampal stem cells during stroke in mice.
Jaime Imitola, M.D and colleagues from Harvard demonstrated for the first time, a molecular mechanism for the responses of NSCs to injury.
The search for additional mechanisms that operate in the injury environment and how they influence the responses of NSCs during acute and chronic disease is matter of intense research.
These neurospheres are composed of neural stem cells and progenitors (NSPCs) with growth factors such as EGF and FGF.
The withdrawal of these growth factors activate differentiation into neurons, astrocytes, or oligodendrocytes which can be transplanted within the brain at the site of injury.
[23] The direct transplantation of NCSs is limited and faces challenges due to low survival rate and irrational differentiation.
Hence, directional induction takes NSCs from different sources and forces them to differentiate into the desired neural lineage cells.
An example of the therapeutic usage of this technique is the targeted differentiation of ventral midbrain dopaminergic (DAergenic) neurons into different models of PD.
Current treatments focus on preventing further damage by stabilizing bleeding, decreasing intracranial pressure and inflammation, and inhibiting pro-apoptotic cascades.
In order to repair TBI damage, an upcoming therapeutic option involves the use of NSCs derived from the embryonic peri-ventricular region.
Stem cells can be cultured in a favorable 3-dimensional, low cytotoxic environment, a hydrogel, that will increase NSC survival when injected into TBI patients.
The intracerebrally injected, primed NSCs were seen to migrate to damaged tissue and differentiate into oligodendrocytes or neuronal cells that secreted neuroprotective factors.
The hGal-1-hNSCs induced better and faster brain recovery of the injured tissue as well as a reduction in motor and sensory deficits as compared to only hNSC transplantation.
[36] In 1989, Sally Temple described multipotent, self-renewing progenitor and stem cells in the subventricular zone (SVZ) of the mouse brain.
[30] In the same year the team of Constance Cepko and Evan Y. Snyder were the first to isolate multipotent cells from the mouse cerebellum and stably transfected them with the oncogene v-myc.
