Spinal Cord Injury Introduction:
Spinal Cord Injury (SCI) is damage to any part of the spinal cord or nerves which results in severe neural dysfunction below the injury site. This damage can lead to lifelong disability and loss of independence . Patients with SCI express sensory, functional and autonomic deficits caused by neuronal and glial cell death, demyelination and axonal degeneration . Basically, the extremity of an injury relies on the section of the spinal cord that is affected. The severeness of the injury is often called “the completeness” and is divided into following:
Complete: it involves loss of all sensory and motor function below the spinal cord injury. Almost 50 % of all spinal cord injuries are complete.
Incomplete: In an incomplete SCI, some motor or sensory function remains below the affected area. In addition, Paralysis caused by spinal cord injury referred to as:
Quadriplegia: Also known as Tetraplegia, which occurs due to injuries in cervical region of spinal cord. This results in loss of muscles strength.
Paraplegia: This occurs due to injuries in the thoracic or lumbar areas of spinal cord which further results in paralysis of lower parts of body and legs .
According to the World Health Organisation (WHO) every year between 250 000 and 500 000 people suffers a SCI globally, majority of them are occurs due to falls or violence and road traffic crashes. People with a spinal cord injury are two to five times more likely to die prematurely compared to people without a spinal cord injury, with worse survival rates in low- and middle-income countries . According to the first global status report on road safety of the WHO, India has the highest number of deaths due to road traffic accidents, with 375 deaths and more than 1200 injuries per day due to road accidents in the country. Trauma is projected to be third largest killer in the developing world by 2020, with a large number of these injuries comprising of spine trauma and traumatic spinal cord injury.
Management of Spinal Cord Injury
There are four types of potential treatments for Spinal cord Injury :
- Repair of the lesion site
- Recruiting preserved tissue
Usage of stem cell on spinal cord injury
Several studies have revealed that stem cells might provide a source of neural cells and also exerts neuroprotective effects after SCI . Among them, mesenchymal stem cells (MSCs) emerged as one of the most promising types of stem cells for the treatment of SCI for following reasons:
(i) Easy to isolate and cryopreserved
(ii) Viability and regeneration potential of MSCs stay maintained after cryopreservation at -80 °C
(iii) Express rapid replication along with high quality progenitor cells and high potential of multilineage differentiation
(iv) Negligible or no immunoreactivity and graft-versus-host reaction of transplanted allogeneic MSCs .
MSCs are ideally suited to approach various pathophysiological outcome of SCI . The major significant objective for therapeutic use of stem cells includes regeneration of axons, prevention of apoptosis and replacement of lost cells, specifically oligodendrocytes to promote the remyelination of spared axons . Various experimental studies demonstrated that MSCs strongly respond to inflammatory or chemotactic stimuli liberated from injured tissues including chemokines and several growth factors like hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and SDF-1α/CXCR4 axis . Studies specify that MSCs with improved migratory ability to the lesion site following SCI increase the antiapoptotic effects via upregulating the expression of stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) axis.
Consistently, the SDF-1α/CXCR4 axis increase cell migration toward injured tissues and promotes recovery after SCI via mediating bone marrow MSCs . Recent data indicated that MSC transplantation inhibits cavity formation occur due to SCI and resulted in following motor recovery after SCI. According to the preclinical experiments in SCI animal model indicating MSC transplantation in the improvement of functional recovery after SCI, number of clinical trials were performed which showed that the transplantation of such cells is safe and advantageous for some patients by using distinct transplantation procedures and cell application methods . In conclusion, number of clinical trials uses MSCs transplantation for the treatment of spinal cord injury, this approach needs continued exploration of basic scientific knowledge of spinal cord injury and proven therapeutic efficacy.
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