Today, thousands of people around the world are paralyzed by spinal cord injuries, and there is still no effective treatment. Recently, two simultaneous articles published in top journals have rekindled hope for patients with complete limb paralysis caused by spinal cord injury!
1. Designed for the first time a human spinal implant for paralysis
In a study published in the prestigious journal Advanced Science on February 7, 2022, scientists at Tel Aviv University in Israel first designed a functional 3D human spinal cord tissue based on human cells and materials and implanted it in a laboratory mouse model characterized by chronic paralysis. The results showed that the ability to walk was successfully restored in 80% of the test subjects.
Research Achievements (Source: Advanced Science)
The groundbreaking study was conducted by an experimental team led by Professor Tal Dvir, head of the Sagol Center for Regenerative Biotechnology at Tel Aviv University.
Professor Tal Dvir, Head of the Sagol Center for Regenerative Biotechnology at Tel Aviv University
(Source: Sagol Center for Regenerative Biotechnology)
Professor Tal Dvir explains, "Our technique is to collect abdominal fat tissue from patients. This tissue, like all tissues in our bodies, consists of cells and an extracellular matrix. After isolating the cells from the extracellular matrix, the cells are reprogrammed using genetic engineering to return them to a state similar to embryonic stem cells. In addition, we prepared a personalized hydrogel from the extracellular matrix that does not cause immunity or rejection after implantation. The stem cells are then encased in a hydrogel and converted into neuronal network 3D implants containing motor neurons in the process of simulating spinal embryonic development."
The human spinal implant was then implanted into a laboratory model, divided into two groups: acute and chronic. The experimental results found that after implantation, 100% of the laboratory models of acute paralysis and 80% of chronic paralysis regained the ability to walk.
This is the world's first example of implanted engineered human tissue producing long-term recovery in animal models and is the most relevant model for the treatment of human paralysis.
Building on revolutionary organ engineering techniques developed by Professor Dvir's lab, he established Matricelf (matricelf.com) in 2019 with industry partners, which takes the approach of Professor Dvir's team to commercialize spinal implant therapy to meet the needs of paralyzed people.
Now, researchers are preparing for the next phase of the study, hoping to enter human clinical trials in the next few years, eventually allowing patients to stand and walk again.
2. Personalized spinal cord treatment enables patients with complete paralysis to quickly restore motor function
On the same day, Nature Medicine published a paper titled Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis. It provides patients with spinal cord injury paralysis with a spinal cord electrical stimulation system that can quickly restore motor function.
At the end of 2018, David Mzee was paralyzed by a partial spinal cord injury in a sports accident, and he later got up from his wheelchair and began walking with the help of a walker. This is the first evidence that a system developed by Professor Grégoire Courtine of the Swiss Federal Institute of Technology and Professor Jocelyne Bloch of Lausanne University Hospital in Switzerland – using electrical stimulation to reactivate spinal cord neurons can work effectively in patients with spinal cord injury paralysis. At the time, the event also made headlines around the world.
The research team, led by Professor Coultine and Professor Bloch and neurosurgeon, optimized their previous system with more complex implants controlled by AI software that could stimulate spinal cord areas that activate trunk and leg muscles, enabling three patients with complete spinal cord injury to walk again outside the lab.
Research Results (Source: Nature Medicine)
Professor Courtine said: "Our stimulation algorithms are still based on mimicking nature, and new implants are designed to be placed directly on the spinal cord, which regulates neurons in specific muscle groups. By controlling these implants, we can activate the spinal cord, just as the brain naturally allows the patient to stand, walk, swim, or ride a bicycle."
The study first surgically implanted new wires into the spinal cord of a paralyzed person, then connected two small remote controls to a paralyzed person's walker and wirelessly connected them to a tablet, which in turn forwarded the signal to a pacemaker in the paralyzed person's abdomen. The pacemaker, in turn, transmits signals to implanted spinal cord wires, stimulating specific neurons that allow paralyzed people to walk.
Professor Bloch said: "Our breakthrough in this area is the implantation of longer, wider wires, and the electrodes are arranged in exactly the same way as the spinal nerve roots, so that the neurons that regulate specific muscles can be precisely controlled."
After the spinal implant was activated, all three paralyzed people participating in the experiment were able to stand, walk, pedal, swim, and control their torso movements within a day! This is because the system writes a specific stimulus program for each type of activity, the patient can select the desired activity on the tablet, and the corresponding signal is forwarded to the pacemaker in the abdomen.
▲One of the patients resumes walking (screenshot source: University Hospital of Lausanne, Switzerland)
Obviously, the progress this study made in one day was staggering, and the results were even more exciting in the months that followed. What's more, because the technology is miniaturized, patients are not limited to the lab, but can train outdoors. The three patients in the experiment now follow this study's training protocol and are able to regain muscle mass, move around independently, and participate in social activities.
The research team is currently working with ONWARD Medical to translate the findings into real treatments that will improve the lives of thousands of paralyzed people around the world.