Stem Cells for Spinal Cord Injury

About SCI

Spinal Cord Injury affects thousands of people worldwide, and is one of the major reasons for lifelong disability. This severe neurological condition is often caused due to trauma, such as road accidents, falls, sports injury, or violence; resulting in paraplegia or quadriplegia. The spinal cord acts as a bridge between CNS and the rest of the body, enabling communication pathways between the two. It contains millions of nerves and bundles of nerve fibres, through which the important signals required for initiating and controlling autonomic functions are transmitted, across different vital organs.

Understanding Autonomic Functions

We don’t have to put much thought into how we should control our body temperature, do we? Our body has an inherent ability to regulate it, like through warming up or through sweating. Likewise, there are many unconscious processes that are regulated and established autonomically by our body through constant communication, established by the spinal cord, and are known as “ Autonomic Functions”.

How are these functions affected following injury?

An injury to the spinal cord may lead to a communication gap, causing impaired autonomic functions. Reportedly, people may experience inability to sweat, uncontrolled bowel/bladder movement, uncontrolled blood pressure,impaired sexual functions as well as in the extreme cases, impaired breathing.

Note: Studies have observed that 92% of the individuals with SCI may experience above symptoms, one year after injury, making it one of the most urgent issues to address.

Until recently it was believed that it is almost impossible to repair spinal cord, post injury. However, with increased understanding of cellular communication, technological advancements and a large database collected from various clinical studies around the world, the first generation of personalized therapies is ready to deliver functional recovery from spinal cord injury.

These therapies primarily revolve around the use of regenerative power of stem cells to re-establish the communication and “awaken” the dormant pathways to improve the lost functions of neural stem cells.

With personalized medicine making rapid progress over the last couple of years, multiple treatment approaches can now be incorporated, depending upon the vertebral location and type of injury.

Diagnosis

The acute traumatic spinal cord injury can be a life changing event, due to involvement of sensorimotor neurons and autonomous dysfunctions. Although, current prognosis and diagnosis strategies are mainly standardized and revolve around assessment of injury levels; they are proven to be inefficient to confirm individual trajectories of recovery. Thus, advanced diagnostic measures with more accurate predictions are required. Typically, following trauma a rapid and conscious transport with restricted motion is very essential. Whereas in case of infectious spinal cord dysfunction, a detailed medical history may provide valuable insights, and accelerate the diagnostic procedure. Upon arrival at the hospital, immediate attention is paid to life-threatening issues like breathing problems, circulatory issues, airway obstructions, etc. Once these challenges are managed, a formal neurological assessments are performed, like:

1. Computed Tomography scan (CT scan): The test helps us get cross-sectional images from different parts of the brain. The test reveals the location, and the extent of damage including underlying issues like blood clot (Hematoma).

2. Advanced MRI (Magnetic Resonance Imaging): The test is helpful to get clear images of the injured areas, including the soft tissues under the bone; revealing underlying abnormalities and issues like herniated discs.

3. Somatosensory Evoked Potential Testing (SSEP): The test is helpful to identify the extent and location of the injury by evaluating sensory pathways in the central nervous system.

4. Biomarkers: Two markers present in serum and cerebrospinal fluid - Neurofilament light chain (NF-L) and glial fibrillary acidic protein (GFAP)- are measured to assess the severity of the condition and the possible outcomes.

Symptoms of Spinal Cord Injury

The symptoms of spinal cord injury depend on the cord segment affected by the injury. Common symptoms include:

• Muscle weakness
• Loss of muscle function
• Loss of sensation pertaining to temperature, vibration, touch, proprioception, etc.
• Impaired balance and posture
• Pain in the neck or back
• Numbing or tingling sensation
• Inability to move arms or legs
• Loss of bladder and bowel control
• Coughing or difficulty in breathing
• Sexual dysfunction
• Loss of grasp to objects

In the long term, the injury can also cause cardiovascular disorders and severe respiratory problems.

Types of Spinal Cord Injury

Spinal cord injury can be classified as follows:

Complete Injury/ Spinal Cord Syndrome: It involves total loss of sensation, muscle function, and muscle control. It affects all segments of the spinal cord.

Incomplete Injury: It shows partial loss of function, retaining sensation and muscle control in some body parts.

Spinal cord injury is also categorized depending on its location or spinal segments:

• Cervical Injury: occurs in the top region of the spinal cord closest to the brain. It can cause full or partial paralysis in all limbs (arms and legs) and the torso, also known as tetraplegia or quadriplegia.
• Thoracic Injury: It affects the muscles of the legs, lower back, and abdomen and might result in partial paralysis in the legs, called paraplegia.
• Lumbar Injury: It involves loss of function in the lower part of the body- hips and legs, without affecting the upper body.
• Sacral Injury: It leads to functional loss in the legs and hips, along with reduced bladder and bowel control.

The American Spinal Injury Association (ASIA) has graded spinal cord injury based on their severity levels.

• ASIA A: Complete spinal cord injury.
• ASIA B: Incomplete spinal cord injury with complete loss of muscle function but retention of sensory functions.
• ASIA C: Incomplete spinal cord injury with intact muscle function (less than half of muscles showing grade 3 strength).
• ASIA D: Incomplete spinal cord injury with intact muscle function (at least half muscles showing grade 3 strength).
• ASIA E: Normal sensation and muscle functions.

Causes of Spinal Cord Injury

Spinal cord injury occurs due to traumatic and non-traumatic incidents.

• Traumatic Incidents: Motor vehicle accidents, violent injuries (stabbing, gunshot), falls, sports injuries, surgical complications, etc., are categorized as traumatic incidents that result in injury to the spinal cord.
• Non-traumatic incidents: Oftentimes, tumors, infections or neuron deterioration also cause injury to the spinal cord.

Tumors and infections can compress the spinal cord, leading to instability and obstruction of blood flow. Disorders such as spondylitis (age-related wear and tear that causes damage), stenosis (narrowing of the spinal column), etc., also result in spinal cord injury. The older generation is more at risk of injury due to age-induced decrease in bone density. This weakens the spinal cord's structural support and increases its susceptibility to fractures and damage. People with bone disorders like osteoporosis and osteopenia are also prone to injury. Injury to the spinal cord is also classified as primary and secondary. Primary injury is the initial damage that occurs due to the abovementioned reasons. Secondary injury occurs within a few minutes after primary injury and lasts up to weeks or months. It includes pathways that are triggered by primary injury, including obstruction of blood flow, inflammation, and production of cell-damaging free radicals. These pathways lead to substantial cell damage. Additionally, ionic imbalance and accumulation of neurotransmitters also disrupt nerve signal transmission.

Treatments for Spinal Cord Injury

Emergency Care: At the time of injury, medical personnel perform spinal motor restriction to limit movement and avoid further damage so that patients can be safely transported to the hospital. Treatment of other life-threatening conditions, such as hypotension, shock, respiratory failure, etc., is prioritized because they can worsen the injury. For example, emergency staff insert a tube for breathing in case of inadequate lung function.

Surgery: Surgical decompression as early as possible is suggested for better outcomes. Surgery to improve structural abnormalities is also recommended.

Symptom Treatment: Further treatment focuses on symptoms of spinal cord injury. For example, tube insertion is used in cases of reduced lung capacity, and catheter insertion is used for bladder control. Drugs for preventing pulmonary embolism, avoiding clot formation, and treating deep vein thrombosis are also prescribed.

Rehabilitation: It combines counselling, emotional support, physical therapy, and activities that increase the patient’s functional independence. They utilize assistive technology, such as braces, wheelchairs, prosthetics, etc., in the initial phase of the therapy. Rehabilitation involves the following therapies:

• Physical Therapy: Exercise to improve muscle strength.
• Occupational Therapy: Enhance motor skills for daily activities.
• Recreation Therapy: Participation in sports and leisure activities.

None of the available treatments can cure the spinal cord injury and the subsequent damage. They aim to avoid more damage and manage the disorder to improve the patient's quality of life.

Stem Cell Therapy: It restores damaged tissue by differentiating into neural cells, secreting factors that protect neural cells, reducing neuroinflammation, forming new neural cells, consuming free radicals, and reestablishing blood flow to the spinal cord. Clinical studies have shown diminishing severity levels and improved functional capacity in individuals treated with stem cells.

Frequently Asked Questions (FAQs)