World’s First 3D Human Spinal Cord Implant May Allow Paralyzed People to Walk Again

For the first time in the world, researchers have engineered human spinal cord implants for treating paralysis, marking a scientific breakthrough that may enable paralyzed people to walk again.

The researchers from Sagol Center for Regenerative Biotechnology at Tel Aviv University (Tel Aviv, Israel) have engineered 3D human spinal cord tissues and implanted them in lab model with long-term chronic paralysis. The results were highly encouraging: an approximately 80% success rate in restoring walking abilities. Now the researchers are preparing for the next stage of the study: clinical trials in human patients. They hope that within a few years the engineered tissues will be implanted in paralyzed individuals enabling them to stand up and walk again. The technology behind the breakthrough uses patient tissue samples, transforming it into a functioning spinal cord implant via a process that mimics the development of the spinal cord in human embryos.

"Our technology is based on taking a small biopsy of belly fat tissue from the patient. This tissue, like all tissues in our body, consists of cells together with an extracellular matrix (comprising substances like collagens and sugars)," said Prof. Tal Dvir who led the research team that conducted the groundbreaking study. "After separating the cells from the extracellular matrix we used genetic engineering to reprogram the cells, reverting them to a state that resembles embryonic stem cells – namely cells capable of becoming any type of cell in the body. From the extracellular matrix we produced a personalized hydrogel, that would evoke no immune response or rejection after implantation. We then encapsulated the stem cells in the hydrogel and in a process that mimics the embryonic development of the spinal cord we turned the cells into 3D implants of neuronal networks containing motor neurons."

The human spinal cord implants were then implanted in lab models, divided into two groups: those who had only recently been paralyzed (the acute model) and those who had been paralyzed for a long time – equivalent to a year in human terms (the chronic model). Following the implantation, 100% of the lab models with acute paralysis and 80% of those with chronic paralysis regained their ability to walk.

"The model animals underwent a rapid rehabilitation process, at the end of which they could walk quite well. This is the first instance in the world in which implanted engineered human tissues have generated recovery in an animal model for long-term chronic paralysis – which is the most relevant model for paralysis treatments in humans. There are millions of people around the world who are paralyzed due to spinal injury, and there is still no effective treatment for their condition. Individuals injured at a very young age are destined to sit in a wheelchair for the rest of their lives, bearing all the social, financial, and health-related costs of paralysis. Our goal is to produce personalized spinal cord implants for every paralyzed person, enabling regeneration of the damaged tissue with no risk of rejection," added Prof. Dvir.

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Tel Aviv University