What is a Motor Neuron Disease?
Motor neuron cells are specialized nerve cells in the brain that send signals through the spinal cord to the muscle nerve cells to perform movements. They are critical to health and normal everyday functioning because they control many voluntary movements like respiration, swallowing, talking, hand gestures and walking.
Motor neuron diseases (MNDs) are a group of fatal neurological disorders that progressively destroy these nerve cells. When the motor neuron cells are destroyed by an MND the muscles cannot receive the brain’s messages, resulting in muscle weakness and wasting. Amyotrophic lateral sclerosis (also known as ALS or Lou Gehrig’s disease) is the most common motor neuron disease, accounting for approximately 85% of motor neuron disease. Other motor neuron diseases include; post-polio syndrome (PPS), primary lateral sclerosis (PLS), progressive bulbar palsy and progressive muscular atrophy.
What are the causes of a motor neuron disease?
It is still unclear as to why motor neurons begin to lose their functions. Some cases of MNDs are inherited and run in the families. Experts believe that a significant cause for the occurrence of MNDs is a genetic mutation that affects cell functioning. Some inherited forms of amyotrophic lateral sclerosis (ALS) are caused by mutations in the SOD1 gene, which helps protect the body’s cells from oxidative damage.
Currently, researchers are investigating factors that may be related to the development of MNDs, such as ALS. These factors include:
- Abnormally high levels of glutamate, a chemical that passes messages between nerves
- Defective immune response in which the immune system may attack the nerves that control muscles, leading to a loss of muscle control
- Environmental factors, such as infections, toxic substances, and dietary deficiencies.
What are the symptoms associated with motor neuron disease?
The symptoms of MNDs can vary as the disease progresses further. The symptoms usually follow a pattern that falls into three main categories;
- The initial stage – the symptoms develop slowly and subtly over time
- The advanced stage – certain body parts and functions are affected and there is an increased incidence of muscle spasms, muscle weakness, pain, respiratory problems, difficulty in speaking and swallowing, difficulty walking and maintaining balance and related problems
- The end stage – mainly characterized by body paralysis, severely affecting daily activities and shortness of breath
Some people with motor neuron disease have additional symptoms that aren't directly caused by the disease but are related to the stress of living with the disease and include depression, anxiety and insomnia.
What are the treatments available for a motor neuron disease?
Currently there is no cure or standard treatment for MNDs.
People with MND and their caretakers have complex needs which can only adequately be delivered by a multidisciplinary team experienced in the management of progressive neurological disability. This should normally include a physiotherapist to advise on mobility, postural support, and prevention of contractures; a speech and language therapist to assess swallowing and provide communication aids; an occupational therapist to provide aids to maintain function (wheelchair, mobile arm supports, etc); a dietitian to advice on maintaining weight and other nutritional requirements.
Medications such as muscle relaxants, anticonvulsants, non steroidal anti inflammatory drugs and other available drugs help by reducing the occurrence of the symptoms. The standard drug that is currently is being used for MND is rilutor. Along with that, Assistive devices such as supports or braces, orthotics, speech synthesizers, and wheelchairs may help some people retain independence. An artificial ventilator support may also be required in the later stages of the disease.
The conventional treatments used for MNDs undoubtedly improve the quality of life of patients. However; the destruction of the motor neurons that occurs cannot be corrected by these methods. Among the various therapeutic options available for MNDs, stem cell therapy holds great promise.
How stem cells work in Motor Neuron Disease
Motor Neuron Disease is characterized by progressive axonal degeneration of motor neurons in the spinal cord and motor cortex. The disease process selectively affects only motor neurons sparing the sensory system.
Stem cells which can differentiate into neural as well as glial cells play a multifaceted role in the regeneration of the lost motor neurons.
Bone marrow derived cells provide a good potential source of stem cells for neural regeneration. They contain both hematopoietic as well as mesenchymal progenitor cells. Both these cells have been known to migrate to the spinal cord and engraft successfully at the site of the motor neuron disease. Stem cells perform the following roles in treatment of MND:-
- Migrated stem cells then differentiate into various neural cells that help in tissue repair.
- Stem cells bring about cell replacement
- They increase cell population
- Provide a better microenvironment for motor neuron survival.
- They also release certain messenger molecules that further enhance protection of the motor neuron cells and protect them from destruction.
Cellular transplantation is an attractive management strategy for MND. The pre-clinical animal studies have shown benefits in the motor function. The safety of autologous stem cell transplantation has been established and allogenic cells transplantation is being studied. Various types of cells, routes of administration and different protocols of administration are being studied widely world over. Transplantation of mononuclear cells derived from peripheral blood using various modes of transplantation like intracerebral, intra-spinal and intrathecal have shown beneficial gains in survival, respiratory function, muscle strength and bulbar impairment. It also slowed disease progression and rate of drop in the respiratory function.
Cellular therapy has been tested widely and has been repeatedly found to be safe and beneficial in MND.
The NeuroGen Outcome
Motor Neuron Disease (MND) occurs in 1-5 people out of 100,000 people worldwide crippling not only them but their hopes, loved ones and their family members.
Now, there is a new shining ray of hope for all those afflicted with MND in the form of Stem cell therapy. At NeuroGen BSI, post stem cell therapy, majority of our patients reported clearer and louder speech, and improved tongue movements. Bulbar symptoms like reduced choking, improved swallowing, reduced saliva drooling, increase respiratory capacity. Few showed better neck control. The limb function was better in few patients. Improvement in some patients showed improvement in the lower extremity function, ambulation, fine motor activities, static and dynamic standing and sitting balance. Together, these improvements it helps the patients’ retain their independence and improves their overall quality of life.
At NeuroGen Brain and Spine Institute, we compared the survival duration of the MND patients treated with intrathecal autologous stem cell transplantation. Comparison of the survival duration using Kaplan-Meier survival analysis suggested that the mean survival duration of the patients treated with intrathecal autologous stem cell transplantation was longer than those who were not treated with stem cell therapy.
Stem cell therapy in combination with standard drug treatment and rehabilitation may lead to slowing down or halting of the progression in MND. It is safe, simple and efficacious, especially when administered in the earlier stage of the disease.