25 Mar 2015

Stem cell transplantation, the future treatment of multiple sclerosis

Multiple sclerosis is a chronic degenerative disease.The major fraction of people treated with disease modifying agents experience flare up of disease. The course of disease is unpredictable, it may progress rapidly or slowly. According to the clinical features there are four different types of MS.Relapsing/remitting MS (RRMS) forms 85% of cases, here  patients are stable in between the bouts and often may recover completely however there is risk of RRMS transforming into secondary progressive MS (SPMS).In SPMS neurological function may steadily deteriorates without clear relapses.

Why treatment is difficult in multiple sclerosis?
clinical manifestation vary from person to person.Treatment is also like this, the drug that works well in one person may not be effective in other person. As the best treatment vary from one person to other treatment need to be individualized.The key to finding the treatment and cure of this disease is through trial and error and research.

Stem cell transplantation in multiple sclerosis
As MS is a complex disease, its successful treatment requires a combination of treatments that control each of the disease mechanisms
2.Loss of nervous system cells
3.Lack of regenerative capacity of particular cell in the central nervous system.

Why stem cells are used?
1.Stem cells have unparalleled regenerative capacity thus offer the promise of filling this therapeutic goal. 
2.They have flexibility to grow into different type of cells and can differentiate into cells that produce the covering of neuron (myelin). 
3.Stem cells are capable of modulating the immune system and able to produce factors that protect the neuron.

Different type of stem cell that are used.
Hematopoietic stem cells (HSCs) are the main type of cells investigated.
Mesenchymal stem cells (MSCs)
Neural stem cells (NSCs) 
Oligodendrocyte precursor cells (OLPs) .

What is done in stem cell transplantation.
First patient with multiple sclerosis is treated with high-dose immunosuppressive therapy, then their own hematopoietic stem cells, are transplanted .This type of transplantation is called autologous transplantation as it is done with patients own cell.
Stem cells are harvested from patients bone marrow and then injected into the Cerebrospinal fluid that surrounds the spinal cord of the patient.Injections are repeated at 3 month intervals frequent monitoring of safety and efficacy is monitored through follow up.After the final injection patient needs monitoring upto 27 months.

How does stem cell transplantation work?
RRMS the most common form of Multiplesclerosis, is a progressive autoimmune disease where the exaggerated immune system attacks the brain and spinal cord. Stem cell transplantation will remove abnormal immune cells that cause disease and reset the immune system.

Result of stem cell transplantation  
There were sustained remission of active relapsing-remitting MS (RRMS in most of the patients and majority experienced improvement in neurologic symptoms). Useful in patients with aggressive disease.

Variables that determines the benefits of stem cell transplantation are the following
1.Maximum benefit is seen in patients with active inflammatory disease which is determined by frequent active relapses and  or gadolinium enhancement on MRI 
2.Better to start the treatment as early as possible before irreversible disability.
3.Use of safe conditioning regimen for immunosuppression.

Early side effects 
Seen on blood and gastro intestinal system and are reversible. 

Success rate in recent trials
Various clinical trials are going on based on stem cell transplantation.There are encouraging and promising results in various studies, upto 80 percentage of trial participants survived  without experiencing an increase in disability, relapse of MultipleSclerosis manifestations or new brain lesions .

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