Two breakthroughs in spinal-cord research

Research on the treatment of paralysis is accelerating, with two just-published studies reporting spinal-cord treatments that could successfully restore motor function.

The first study, published in Nature Medicine, announces the success of a personalised electrical stimulation treatment in three patients with paralysis from spinal-cord injuries.

Electrical stimulation has been shown to restore some muscle function after spinal-cord injuries. Specifically, electrical stimulation at the base of the spine, or epidural electrical stimulation (EES), can restore bladder movements and even walking in some patients with previously complete paralysis.

This global team of researchers, based at the Swiss Federal Institute of Technology, has developed an electrode paddle that improves on this EES technique.

Rather than targeting the dorsal column, as previous EES has, the paddle is designed to stimulate all the nerves that are linked to leg and trunk function.

The researchers paired this with purpose-built software that determines the precise placing of the paddle for each patient, and the amount of electrical stimulation required for specific activities.

When tested on three male patients with complete sensorimotor paralysis, all between 29 and 41 years of age, the paddle could rapidly restore motor function.

Within a day of the EES treatment, each patient was able to walk and swim or cycle.

“This recovery, combined with our previous findings in people with incomplete SCI [spinal cord injury], is opening a realistic pathway to deploy a therapy that will mediate clinically meaningful improvements in people presenting with a broad range of SCI severities,” conclude the researchers in the paper.

The researchers state that, since the method and software is highly personalised, scaling it up for other patients will need AI and machine-learning programs to assist neurosurgeons and EES specialists.

Read more: Paralysed man ‘handwrites’ with brain chip

In a second, unrelated study, a team of researchers has grown human spinal-cord tissue, which – when implanted in animals – could successfully restore walking in 80% of subjects.

“Our technology is based on taking a small biopsy of belly fat tissue from the patient,” explains Professor Tal Dvir, a biotechnologist at Tel Aviv University, Israel, and author on a paper describing the research, published in Advanced Science.

“This tissue, like all tissues in our body, consists of cells together with an extracellular matrix (comprising substances such as collagens and sugars). 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.”

The researchers made a hydrogel from the extracellular matrix, which, being made from human tissue, wouldn’t provoke an immune response.

“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,” says Dvir.

The researcher tested this tissue both in animals with acute paralysis (recently caused), and animals with chronic paralysis (equivalent to a year of a human’s life). In the acute group, 100% of animals could recover enough to walk again with rehabilitation, while 80% of the chronically paralysed animals could walk.

“We hope to reach the stage of clinical trials in humans within the next few years, and ultimately get these patients back on their feet,” says Dvir.

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