Stem cells therapy as a treatment for spinal cord injury

Spinal cord injury results in severe damage to motor, sensory and autonomic nervous functions and may leads to paraplegia and tetraplegia. Due to cellular loss, regeneration after spinal cord injury is limited1 and current approaches to treat spinal cord injury do not lead to complete cure. Embryonic stem cells transplantation (embryonic central nervous system or human umbilical cord blood stem cells) has been shown to successfully replace host neurons, enhance axonal growth, and improve functional recovery in rat models of spinal cord injury.2-4 Stem cell therapy proves to be promising candidate to treat SCI. Embryonic stem cells (ESCs) are undifferentiated cells that have the ability to proliferate in undifferentiated state both in vitro and in vivo conditions which means they have the capacity of self-renewal and to differentiate into mature specialized cells such as motor neuron. New approaches in stem cell therapy using neuro stem/progenitor cells are widely accepted for the treatment of degenerative diseases for the repair of damaged or lost tissues.5 For stem cell therapy there are several cell sources, including fetal spinal cord tissues6, neural stem cells (NSCs) from adult brains7, and mesenchymal stem cells (MSCs) from bone marrow8 and other organs9, in addition ESCs is another source.10 Human embryonic and adult stem cells both have potential use for cell based regenerative therapies. Of course they differ in many respects like number and differentiated cells types they can become. ESCs are pulripotent stem cells so these can differentiate into all cell types while adult stem cells (ASCs) can differentiate into few cell types. Their longevity and capacity to produce specialized cells in laboratory is the unique potential of human ESCs. By contrast, ASCs have much shorter life span when grown in laboratory.