Doctors are in a race against time when someone has a spinal cord injury. To minimize the damage, doctors urgently operate patients and treat them with anti-inflammatory drugs ranging from over-the-counter pain relievers like Advil to the steroid methylprednisolone, keeping in mind that post-injury swelling and lack of blood flow can further damage neurons. Scientists have long believed that after intervention in this small time frame, the possibility of further recovery is minimized.
Aileen Anderson, a stem cell researcher at the University of California at Irvine, tells Inverse that the “dominant thought” at the time was to focus on acute injuries. “This was the place to be targeted,” the author said. “If you can find a magic bullet in that moment and minimize the amount of damage done as it rolls over days or weeks…
In recent years, however, laboratories have made significant advances in cutting-edge methods that can be used long after the spinal cord is initially damaged. Examples include using electrical currents to reawaken important nervous system pathways and surgeries that can allow injuries to heal on their own.
According to the National Center for Spinal Cord Injury Statistics, these techniques improve the chances of recovery for patients who suffer serious spinal cord injuries for years or even decades and can spend millions of dollars on medical treatment and living expenses throughout their careers.
Sports-related injuries, falls, and traffic accidents are the leading causes of spinal cord injuries in the United States, according to a 2016 study. It affects around 17.000 people a year, which is a relatively modest number. Yet a large proportion of the population continues to suffer from chronic injuries (estimates range from 250.000 to 1 million people, Anderson says).
For those with permanent disabilities, even modest improvements can ultimately yield huge benefits, according to Michael Fehlings, MD, a neurosurgeon at Toronto Western Hospital in Canada. When costs such as several caregivers, electric wheelchairs, and home renovations are factored in, the full-body paralysis that the late Superman actor Christopher Reeve suffered, for example, could cost a person $10 to $20 million.
"The economic and human impact of a treatment that can partially restore hand and upper extremity function and restore a person's independence is enormous," says Fehlings.
The spinal cord is a long, delicate column of nerve cells and thin fibers called axons that transmit signals back and forth between the nerves of the brain and other body parts. Among many other vital tasks, this constant communication tells the muscles how to move, aids in the perception of pain and controls heart rate.
Injuries can disrupt nervous system circuits and damage nerve connections. For example, these interruptions can cause loss of movement or uncontrollable movements in certain body parts.
According to the National Institutes of Health, blows higher up on the spinal cord can result in quadriplegia or tetraplegia, a condition in which most of a person's body is paralyzed. The specific symptoms experienced by an individual vary with the location of the lesion. Lower spinal cord injury can result in paralysis, also known as paraplegia, which affects the legs and lower body.
According to Fehlings, early treatments such as spinal decompression surgery and anti-inflammatory drugs have long been thought to be essential for recovery. Moreover, studies have examined methods such as cooling individuals with spinal cord injuries. Still, Anderson contends that numerous non-surgical interventions ultimately yield only mediocre results in research.
Numerous ways have been developed in the lab not only to reduce early damage, but he adds that this has led to a large number of failed clinical trials.
Patients may now find some relief from side effects such as muscle spasms and decreased bladder control. Still, most treatments currently available in clinics fail to repair the damage underlying these symptoms.
According to Susan Harkema, deputy director of the Kentucky Spinal Cord Injury Research Center, “currently there are no treatments that cure people with permanent spinal cord injury. Most of the clinically approved drugs are used to relieve symptoms.
These treatments include locomotor training, a type of rehabilitation developed by Harkema and his friends at the University of Louisville. During the rehabilitation session, patients can use a harness to provide support as a robot or staff members move their legs on the treadmill. But Anderson notes that only a few facilities provide this type of rehabilitation.
In addition, patients can be treated with electrical stimulation, a method first developed in the 1960s. Using electrodes placed on the skin or implanted close to the spinal cord, this technique delivers modest levels of electrical current to the spinal cord. These tools are designed to mimic how the brain normally transmits messages to various parts of the body and restore mobility in potentially injured parts.
According to Fehlings, there are certain circuits in the neurological system that survive even when a person is seriously injured. There is good reason to use electrical stimulation to try to activate some of these circuits by "trickling" the nervous system.
Electrical stimulation has proven to have advantages such as increasing the efficiency of rehabilitation and restoring some arm and leg movements. In fact, it has even helped people walk again, along with serious physical training, by activating the nerves that regulate lower body mobility.
Due to the severity of the damage, it is probably not viable for people with whole-body paralysis, but electrical stimulation can still enable some movements that would otherwise not be possible, such as better grip and strength in the hands.
According to Harkema, even 40 years after the injury, people who are completely paralyzed can move freely if the spinal cord is stimulated.
Abbott's Proclaim Plus device and Saluda's Evoke System are two electrical stimulation devices that have received approval from the US Food and Drug Administration in recent years.
The scientists aim to identify the specific set of neurons responsible for the success of the stimulation, in order to more efficiently target them throughout the process.
Real-time stimulation increases people's mobility, so some labs are even developing high-tech equipment with electrodes to help people on the move without the need for surgical implants. This could be a game-changing innovation. The ultimate goal is for people to be able to act without the need for stimuli.
Fehlings says this strategy is exciting. While there is no cure for spinal cord injury, it may offer hope to people with permanent spinal cord injury.
Stem Cell Therapy for the Spinal Cord
Some researchers aim to implant stem cells into the spinal cord to restore sensory and motor function, possibly the most innovative idea. Many phase 2 human clinical trials are underway for this approach, which has shown promise in animal research.
The new cells are expected to replace the damaged ones and restore the signaling pathway in the spinal cord. Anderson also says that in the future, stem cells from the patient's own body could be used in transplants, potentially eliminating the harmful effects of transplant rejection.
Above all, this method could benefit patients who do not have enough viable brain cells to benefit from other treatments currently in use.
“The cellular transplantation technique is trying to treat patients with a spinal cord injury that is so gruesome that even electrical stimulation wouldn't work,” explains Fehlings.
As an additional strategy to help reconnect the spinal cord, several teams, including Anderson and colleagues, are trying to place special materials, such as hydrogel scaffolds, on patients' spinal cords. Combining scaffold and stem cells may also be beneficial, according to Anderson. This concept is still in its infancy.
Lack of funding may prevent many patients from benefiting from these strategies, even if some show promise in clinical trials. Pharmaceutical companies may not see these ideas as worthwhile investments due to the relatively low annual incidence of spinal cord injury.
Yet these injuries have much in common with diseases that also affect the central nervous system, such as multiple sclerosis, stroke, and traumatic brain injuries.
“With what we have developed for spinal cord injury, we hope we can demonstrate that it can affect this broader spectrum of diseases, so it is worth investing in,” he adds.
Fehling hopes that in the next five to ten years, regenerative medicine techniques, such as stem cell transplants, will become available in clinics despite obstacles. If this happens, the lives of patients who cannot benefit from currently available solutions could be changed.
He claims that the era of regenerative medicine is “at a crossroads.” “I am very hopeful.”
Günceleme: 05/03/2023 21:54