3D human spinal cord implants could help treat paralysis

A team at Sagol Center for Regenerative Biotechnology at Tel Aviv University developed functional spinal cord tissues and implanted them in lab models that featured chronic paralysis.

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.

According to Professor Tal Dvir, who led the study, the team’s technology is based on taking a small biopsy of belly fat tissue from the patient. This tissue, like all tissues in our body, comprises cells together with an extracellular matrix (comprising substances like collagens and sugars).

Prof. Dvir explained: “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 personalised 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 paralysed (the acute model) and those who had been paralysed for a long time – equivalent to a year in human terms (the chronic model).

According to the researchers, the results from the study were “highly encouraging”. Following the implantation, 100 per cent of the lab models with acute paralysis and 80 per cent of those with chronic paralysis regained their ability to walk.

Prof. Dvir explained: “The model animals underwent a rapid rehabilitation process, at the end of which they could walk 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 paralysed because of spinal injury and there is still no effective treatment for their condition. Individuals injured at a very young age will sit in a wheelchair for the rest of their lives, bearing all the social, financial and health-related costs of paralysis.”

Prof. Dvir also expressed that the team’s goal is to produce personalised spinal cord implants for every person with paralysis, enabling regeneration of the damaged tissue with no risk of rejection.

The researchers are now preparing for the next stage of their study: clinical trials in human patients. They hope that within a few years, the engineered tissues will be implanted in paralysed individuals, enabling them to stand up and walk again.

“The company’s preclinical programme has already been discussed with the FDA,” Prof. Dvir said. “Since we are proposing an advanced technology in regenerative medicine, and since at present there is no alternative for paralysed patients, we have good reason to expect relatively rapid approval of our technology.”