Spinal cord injuries (SCIs) affect approximately 300,000 Americans, with about 18,000 new cases occurring per year. One of these patients, Jake Javier, who we have written about many times over the past several years, received ten million stem cells as part of a CIRM-funded clinical trial and a video about his first year at Cal Poly depicts how these injuries can impact someone’s life.
Currently, there is nothing that completely reverses SCI damage and most treatment is aimed at rehabilitation and empowering patients to lead as normal a life as possible under the circumstances. Improved treatment options are necessary both to improve patients’ overall quality of life, and to reduce associated healthcare costs.
Scientists at UC San Diego’s School of Medicine and Institute of Engineering in Medicine have made critical progress in providing SCI patients with hope towards a more comprehensive and longer lasting treatment option.
In a study partially funded by CIRM and published in Nature Medicine, Dr. Mark Tuszynski’s and Dr. Shaochen Chen’s groups used a novel 3D printing method to grow a spinal cord in the lab.
Previous studies have seen some success in lab grown neurons or nerve cells, improving SCI in animal models. This new study, however, is innovative both for the speed at which the neurons are printed, and the extent of the neuronal network that is produced.
To achieve this goal, the scientists used a biological scaffold that directs the growth of the neurons so they grow to the correct length and generate a complete neuronal network. Excitingly, their 3D printing technology was so efficient that they were able to grow implants for an animal model in 1.6 seconds, and a human-sized implant in just ten minutes, showing that their technology is scalable for injuries of different sizes.
When they tested the spinal cord implants in rats, they found that not only did the implant repair the damaged spinal cord tissue, but it also provided sustained improvement in motor function up to six months after implantation.
Just as importantly, they also observed that blood vessels had infiltrated the implanted tissue. The absence of vascularized tissue is one of the main reasons engineered implants do not last long in the host, because blood vessels are necessary to provide nutrients and support tissue growth. In this case, the animal’s body solved the problem on its own.
In a press release, one of the co-first authors of the paper, Dr. Kobi Koffler, states the importance and novelty of this work:
“This marks another key step toward conducting clinical trials to repair spinal cord injuries in people. The scaffolding provides a stable, physical structure that supports consistent engraftment and survival of neural stem cells. It seems to shield grafted stem cells from the often toxic, inflammatory environment of a spinal cord injury and helps guide axons through the lesion site completely.”
In order to make this technology viable for human clinical trials, the scientists are testing their technology in larger animal models before moving into humans, as well as investigating how to improve the longevity of the neuronal network by introducing proteins into the scaffolds.