Inducing Endogenous Cells in Alzheimer’s Disease Therapy
Current strategies for treating patients with AD mainly focus on cholinergic neurotransmission, Aβ clearance as well as delivering NGF to the targeted region of the brain. However, these therapeutic methods can only alleviate symptoms associated with AD to some extent but cannot alter the degeneration and loss of neurons in brains of patients with AD; thus, they cannot cure the disease.[34] Hence, newer strategies are needed to alter the pathophysiology in order to obtain long‑term benefits.Enhancement of neurogenesis may be an effective treatment.Several neuroprotective factors that can promote neurogenesis have been used for treatment of AD in animal models. It was shown that administration of encapsulated vascular endothelial growth factor helped in reversing behavioral deficits, reducing Aβ deposits and promoting angiogenesis, as well as reducing neuronal loss in APP/PS1 mice, a kind of transgenic model of AD.[35] In addition, Anitua et al. found that the intranasal delivery of plasma that was rich in growth factors was able
to activate neuronal progenitor cells, enhance hippocampal neurogenesis, and reduce Aβ‑induced neuro‑degeneration
in APP/PS1 mice.[36] Other factors, such as NGF, BDNF, and transforming growth factor, are also known to potentiate NSC generation as well as cell signal mediator function in several neurodegenerative processes, both in vitro and in vivo models.[37] Although endogenous NSCs can be induced, and the newly generated neurons can partially compensate for the neuronal loss in AD, they are not permanent substitutes for the damaged neurons. Moreover, administration of these drugs always needs a craniotomy and repeated injection. Hence, these limitations call for the introduction of exogenous NSCs in AD treatment.