Annual Research & Review in Biology

Stem cells are unipotent (producing only one cell type, i.e. their own), pluripotent (giving rise to all cell types making up a body), or multipotent (having the ability to develop into more than one type of cell but less than that possessed by pluripotent) cells possessing an unlimited ability to proliferate and differentiate under proper culturing conditions. They can be conveniently obtained from the inner cell mass of mammalian embryos in the blastocyst stage (ESCs, which are pluripotent) and adult tissues (ASCs, which are multipotent so far). Human embryonic stem cells (hESCs) proved to be fatal for the embryos owing to which induced pluripotent cells (iPSCs) have been developed by forcibly inducing the expression of specific regenerative genes. All types of pluripotent stem cells, which include ectodermal stem cells, mesenchymal stem cells and rare types of endodermal stemcells, are used in treating several early onset neurodevelopment diseases and late-onset neurodegenerative disorders. Neural stem cells (NSCs) can be found in the developing and adult central nervous system (CNS) and form a population comprising astrocytes, oligodendrocytes and neurones. Several researches conducted in animal models have shown structural and functional recovery as they have been researched on to treat diseases like stroke, brain tumours, metastatic tumours, human primary tumours, spinal cord injury and multiple sclerosis and, for this purpose, neural stem cells enjoy a pivotal status. Their efficacy and safety has been proven not only by the data collected from literature, but also from researches in animal models induced with various neurological disorders.