Spinal cord injury is a serious condition where the spinal cord is damaged as a result of sudden trauma, leading to severe paralysis and impaired sensation.
Current medical treatment focuses on surgical bone fixation, pharmacological suppression of inflammation, and rehabilitation to prevent further progression. However, a truly "curative" treatment method for lost neurological function has not yet been established.
For this reason, patients with spinal cord injuries often face long-term consequences such as paralysis. However, in recent years, Stem Cell Therapy, recognized as a "regenerative medicine," has garnered significant attention, and new possibilities have emerged for pursuing recovery without resigning themselves to spinal cord injuries.
The following outlines current treatment challenges, the novel prospects of Stem Cell Therapy, its mechanism of action, evidence of effectiveness, safety, and related topics, presented in an easily understandable manner for the general public.
Spinal Cord Injury and Current Treatment Challenges
The spinal cord can be described as the "main neural highway" that carries commands from the brain to the body.
When this spinal cord is damaged, the transmission of signals to the neural circuits below it is interrupted. Analogous to a major highway severed by a traffic accident, signals from the brain can no longer traverse.
Consequently, in the regions distal to the site of injury, there is a loss of motor function in the hands and feet, accompanied by sensory loss, leading to paralysis. Furthermore, autonomic nervous system functions, such as micturition, defecation, and perspiration, are also impaired, profoundly affecting the quality of life.
Currently, standard medical treatment, in the acute phase immediately following an accident, first involves surgical intervention to decompress the spinal cord from fractured bone fragments and protruding intervertebral discs, and to stabilize the spine. Concurrently, treatments such as steroid administration are initiated to suppress the progression of secondary damage (i.e., neurological damage resulting from inflammation and swelling).
Subsequently, rehabilitation became the primary focus, training the body to maximize movement utilizing residual neurological function.
However, severed spinal nerve fibers do not readily regenerate naturally, making it challenging to fully restore lost function with current treatments alone.
The lack of effective treatment for spinal cord injury symptoms presents a significant challenge in Japan, affecting over 150,000 patients nationwide, with approximately 5,000 new cases occurring annually.
Nevertheless, a novel approach offering hope for patients and their families is emerging.
It was Stem Cell Therapy through regenerative medicine.
It was previously believed that "recovery could not be expected in the chronic phase (i.e., a considerable time after the injury)." However, recent research findings are beginning to challenge this conventional wisdom. With the advent of Stem Cell Therapy, the potential for functional improvement has been observed even in individuals for whom a considerable time has elapsed since their spinal cord injury.
Spinal Cord Injury and Stem Cell Therapy: New Possibilities in Regenerative Medicine
Stem Cell Therapy is a medical treatment method that utilizes stem cells, which possess the ability to differentiate into various cell types within the body or facilitate tissue repair, to achieve the regeneration of damaged tissue.
Regenerative therapies for spinal cord injury, involving the transplantation of stem cells to the site of damage or their systemic administration via infusion, are being researched and implemented worldwide.
There are several types of stem cells. For example, stem cells derived from the patient's own bone marrow or fat, or stem cells derived from the umbilical cord of another donor.
Among these, Wharton's Jelly-derived stem cells (WJ-MSCs), found in the umbilical cord, possess high proliferative capacity, differentiation potential, and characteristics that make them less prone to immune rejection. They are considered promising for the treatment of spinal cord injury. (Details regarding the characteristics of Wharton's Jelly-derived stem cells are omitted from this article, but their effectiveness has been indicated.)
This stem cell therapy holds the potential to repair and regenerate the damaged spinal cord itself, and is anticipated to achieve functional recovery and improvement in paralysis not attainable with conventional treatments.
Emerging as a new frontier in regenerative medicine, clinical trials and various therapies are already being conducted internationally. Notably, a clinical trial at the Mayo Clinic in the United States demonstrated that autologous adipose-derived stem cell therapy led to a reduction in the severity of paralysis in 7 out of 10 patients, with its safety also being confirmed.
Similarly in Japan, Keio University undertook the world's first attempt to transplant iPS-derived neural precursor cells, with reports indicating improved motor function in 2 of 4 spinal cord injury patients.
Thus, stem cell-based regenerative medicine is garnering global attention as a promising new therapeutic option for spinal cord injuries.
Mechanism of Action of Stem Cell Therapy for Spinal Cord Injury
Why can administering stem cells repair spinal cord injuries?
The following mechanism of action is widely considered for Stem Cell Therapy.
Accumulation at the site of damage
Once introduced into the body, stem cells exhibit homing capabilities, congregating at sites of damage. Analogous to an internal "repair team," stem cells migrate to the compromised spinal column and initiate reparative processes.
Suppression of inflammation
After a spinal cord injury, an excessive inflammatory reaction occurs, and it is neededCurbing the wild immune systemLiterally. Stem cells have the ability to regulate the immune system and calm inflammation that is abnormally increased in damaged areas.
Specifically, they mitigate secondary neuronal damage by directly acting on immune cells or secreting anti-inflammatory substances.
Secretion of growth factors and similar substances:
Stem cells secrete substantial amounts of bioactive molecules, referred to as cytokines and growth factors. These are collectively known as the secretome and are crucial for supporting neuronal survival and regeneration.
For example, substances such as BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor) are released, assisting damaged nerve cells with nutrients and growth signals, thereby promoting axon (nerve fiber) regeneration.
In short, stem cells play a roleFertilizing a damaged garden with nutrient-rich fertilizer to grow new shoots.
Scar tissue repair and blood flow restoration.
Following spinal cord injury, glial cells form scar tissue around the lesion, which acts as a physical barrier and inhibits neural regeneration.
Research has shown that stem cells have the effect of partially remodeling and softening these fibrotic walls.
Additionally, to restore blood flow, such as the reduced capillary flow at the site of damage,Creating new blood vessels is also a specialty of stem cells.In this way, the environment at the site of damage is optimized, creating a foundation for nerves to grow and extend freely (similar to the image of preparing barren land and re-bridging it).
Experiments using stem cells and their secretory products (secretome) have confirmed alterations in injury-induced scar tissue structure, promotion of angiogenesis, and promotion of nerve fiber elongation (regeneration).
Tissue and Cell Replacement
It is also possible that the stem cells themselves differentiate into neural progenitor cells or supporting cells (such as glial cells) and replenish the lost cells.
However, in the case of the spinal cord, the direct replacement rate of neurons (nerve cells) by stem cells is reportedly not high. Instead, indirect reparative effects, achieved through environmental amelioration and the aforementioned protective measures, are considered crucial.
Tissue and Cell Replacement
It is also possible that the stem cells themselves differentiate into neural progenitor cells or supporting cells (such as glial cells) and replenish the lost cells.
However, in the case of the spinal cord, the direct replacement rate of neurons (nerve cells) by stem cells is reportedly not high. Instead, indirect reparative effects, achieved through environmental amelioration and the aforementioned protective measures, are considered crucial.
As explained above, Stem Cell Therapy works by controlling spinal damage from various angles and promoting regeneration. If expressed in one word, the image isStem cells build damaged and disconnected bridges in neural circuits, and help with repair work..
Owing to this mechanism, spinal regeneration, previously considered impossible, is progressively becoming more achievable.
Evidence of Effectiveness of Stem Cell Therapy for Spinal Cord Injury
Instances of genuine functional recovery in spinal cord injuries following Stem Cell Therapy are increasingly being reported globally, albeit still within the research phase. We will present some of this key evidence and its underlying scientific basis.
Enhancement of sensory function (clinical trial - chronic phase):
In a clinical trial for chronic spinal cord injury conducted in Spain, treatment involved a single injection of umbilical cord-derived stem cells (WJ-MSC) into the patient's lumbar region.
Consequently, it has been confirmed that pain perception (pinprick sensation) significantly improved in the dermatomes below the level of injury. This is a promising result, demonstrating that even in patients with long-standing spinal cord injuries, a partial return of sensation is achievable.
Additionally, improvements in autonomic nervous system function, such as bladder function (increased storage volume and reduced hyperactivity), were also observed in some patients.
Improvement in motor function (clinical trial - subacute to the chronic phase)
In a clinical trial of adipose-derived mesenchymal stem cells (AD-MSCs) conducted at the Mayo Clinic in the United States (CELLBERANDA trial), stem cells were transplanted into 10 patients with traumatic spinal cord injury, and their progress was monitored for 2 years.
The results showed that in 7 out of 10 patients, the neurological function grade improved by at least one level (an increase in AIS grade), and notably, one patient became a "super-responder" with significant recovery of upper and lower limb function following treatment.
Historically, severe paralysis resulting from spinal cord injury was considered irreversible. However, this research demonstrates that Stem Cell Therapy can lead to an improvement in paralysis.
Comprehensive functional improvement (clinical research - Japan)
In Japan as well, cutting-edge clinical research in regenerative medicine is being conducted.
In a Keio University study, iPSC-derived neural precursor cells were transplanted into spinal cord injury patients, and it was reported that two of four cases demonstrated improved motor function, including walking and hand movements.
This represents a global first and is recognized as evidence originating from Japan.
Promising results in animal studies:
Extensive research is conducted not only on human clinical cases but also on animal models.
When bone marrow- or umbilical cord-derived stem cells are administered to rat or mouse spinal cord injury models, reports have accumulated indicating improved hindlimb motor function, and observed axonal regeneration and reduced scarring in spinal cord tissue.
These preclinical research findings have paved the way for clinical application in humans.
A is complete paralysis, B-D are incomplete paralysis, E is normal.
Cases have been reported where, despite not achieving a dramatic "cure," there is a return of sensation, increased motor function, and improved autonomic nervous system function, leading to significant enhancements in patients' quality of life.
It should be noted that not all patients experience the same effect. There is significant individual variability, and in some cases, the effect may not be clearly discernible.
However, the very fact that such positive changes can occur in spinal cord injuries previously considered "irreversible" is a breakthrough in itself, and represents a new hope ushered in by Stem Cell Therapy.
Safety of Stem Cell Therapy for Spinal Cord Injury and Side Effects
Safety is a paramount concern when embarking on new treatments. While Stem Cell Therapy is a relatively nascent field, current research demonstrates a relatively high safety profile.
Here are the key points.
Virtually no serious side effects were reported.
Currently, in patients with spinal cord injury receiving Stem Cell Therapy, there have been no reports of severe and life-threatening adverse effects or complications.
For instance, even in the aforementioned Mayo Clinic clinical trials, no serious adverse events occurred. Similarly, in trials involving the intrathecal administration of umbilical cord-derived stem cells, no severe side effects were observed.
This is because stem cells are inherently present in the body, and when properly prepared and managed, they demonstrate a relatively high degree of compatibility with the human system.
Most reported side effects are temporary.
The majority of reported side effects following Stem Cell Therapy are mild and transient. Specifically, these may include headache, fever, transient blood pressure fluctuations, and injection site pain.
It typically resolves within a few days, and symptomatic therapy with analgesics or antipyretics is believed to be sufficient.
Meticulous aseptic technique was employed for infection prevention; however, a system was implemented to manage unforeseen infection risks through antibiotic administration and similar measures.
Consideration is also given to the risk of immune rejection and malignancy.
When utilizing allogeneic stem cells (e.g., umbilical cord-derived WJ-MSCs), concerns about potential immunological rejection may arise. However, mesenchymal stem cells (MSCs) are characterized by their low immunogenicity, and it is known that even cells from non-HLA-matched individuals are relatively well-tolerated.
Nevertheless, repeated administration may lead to antibody formation, necessitating careful consideration of treatment schedules. Moreover, due to the high proliferative capacity of stem cells, the theoretical risk of malignancy (tumor transformation) is also non-zero.
However, for mesenchymal stem cells currently in clinical use, no such reports of malignancy have been documented, and appropriate culture and management methods ensuring safety are employed.
Overall, the safety profile of Stem Cell Therapy is considered good within the scope of current research.
Naturally, as this is a novel treatment, some aspects remain to be fully understood. However, it is precisely for this reason that our expert team is meticulously gathering data and is committed to providing treatment in a manner that minimizes patient burden.
The paramount priority is to ensure patients receive treatment calmly, and clinic operations are structured such that safety management and efficacy verification are conducted in parallel.
Conclusion
Stem cell therapy for spinal cord injuries represents a cutting-edge medical advancement, transforming despair into hope. Spinal cord regeneration, previously considered impossible, is gradually becoming a reality through the inherent reparative capabilities of stem cells.
Clinical research findings have demonstrated the potential for even minimal restoration of movement and sensation in paralyzed individuals, instilling considerable optimism in patients and their families.
It is important to note that Stem Cell Therapy is not a panacea, and currently involves aspects that are still in the research phase. However, with continuously accumulating evidence and technological advancements, its safety and efficacy are progressively enhancing annually.
Specifically, stem cells, such as Wharton's Jelly-derived mesenchymal stem cells (WJ-MSCs), with their minimal ethical restrictions and abundant supply, are expected to play an increasingly central role in future spinal cord injury treatments.
The availability of facilities providing genuine treatment is also gradually increasing, and there are cases where individuals can participate in treatment within the framework of clinical trials or advanced therapies.
Treatment for spinal cord injuries does not have a definitive endpoint.
Medical science is advancing rapidly, continually expanding the realm of patient possibilities. Among these advancements, Stem Cell Therapy stands out as a highly compelling field. It is bringing about extraordinary improvements, such as a hand that was previously immobile regaining movement and the cessation of lifelong debilitating sensations, which are now becoming a reality.
It is essential to accurately understand the latest treatment information and consult with reliable medical facilities. For individuals affected by spinal cord injuries and their families, we urge you not to lose hope.
Regenerative medicine, leveraging stem cells, offers the promise of 'hope for tomorrow'. As medical professionals, we are dedicated to the relentless pursuit of safety and efficacy as we develop treatments to transform that hope into a certainty.