New solution developed for life-threatening complication of spinal cord injury

By Charissa Egger

Novel research by Aaron Phillips, associate professor at the University of Calgary, may soon drastically change the lives of those who suffer from a life-threatening and often underappreciated complication of spinal cord injury: blood pressure instability. Phillips, a senior and corresponding author on two research papers published today in Nature and Nature Medicine, has uncovered the underlying pathology of blood pressure instability and also developed the first viable treatment for this condition.

Back in 2019, Phillips was one of the first researchers to receive a grant from the Brain Canada Future Leaders in Canadian Brain Research program. The program enables researchers early in their careers to explore bold, high-risk, high-reward ideas. Under the grant, Phillips researched the neural circuits that cause blood pressure instability in spinal cord injury patients. He also began testing a new therapy he was developing for blood pressure instability. Now, the results of that research have yielded exciting discoveries for the field and patients alike.

An underappreciated condition

Blood pressure instability is often a less-talked-about symptom of spinal cord injury. It’s not visually apparent like limb paralysis, but it is nevertheless a top priority in spinal cord injury management.

“We’ve known for about 15 years now that blood pressure instability is a higher priority than walking again for people with spinal cord injury,” Phillips says, adding that blood pressure instability comes with chronic symptoms such as headaches or anxiety that greatly impact quality of life.

Patients with blood pressure instability live with chronically low blood pressure due to the paralysis of the muscles surrounding blood vessels below the site of injury. At the same time, patients can also experience episodes of dangerously high spikes in blood pressure — a condition known as autonomic dysreflexia — an inappropriate blood pressure response to otherwise normal stimuli, such as a full bladder. These episodes, if left untreated, can be fatal.

Currently, managing patients with blood pressure instability means tackling low blood pressure and high blood pressure separately. And there is no effective therapy for the potentially life-threatening swings in blood pressure.

Landmark discoveries

In their latest research, Phillips and colleagues discovered a specific subpopulation of neurons in the spinal cord that malfunction after spinal cord injury, leading to autonomic dysreflexia. With this discovery, the team explored potential treatments.

The team found that electrically stimulating the area where these neurons reside — called the hemodynamic hotspot — normalised blood pressure within minutes and eliminated the episodes of high blood pressure.

“The blood pressure spikes ceased to exist, it was a very strong positive effect, which was remarkable and so promising for the community,” Phillips describes.

The device was effective not only at treating blood pressure spikes but also at stabilising low blood pressure. “It’s one intervention, one tool, and you’re treating both sides of the blood pressure swings — the highs and the lows,” Phillips says.

The team developed and tested the technology in humans, creating and patenting a clinical-grade device in partnership with Onward Medical. Implanted onto the spinal cord, the device delivers precise stimulation targeting the hemodynamic hotspot that controls blood pressure. The device also operates in a closed loop, meaning it actively monitors and delivers stimulation as needed to stabilize blood pressure in real time—similar to how a thermostat regulates temperature. In their most recent study, the researchers tested the device on 14 people across multiple countries. Not only did the treatment normalise blood pressure, but it also dramatically improved patients’ daily lives, demonstrating both safety and efficacy for long-term use.

A hopeful future for treatment

The next step, Phillips says, is a Phase 3 clinical trial — “this is really the last step before the device can be made available to the community and make it available to everyone.” Phillips is currently working with the U.S. Food and Drug Administration to move the process forward and is optimistic the treatment could be available to patients in the coming years.

“We think this is a huge need in the spinal cord injury community. We know that more than half of spinal cord injury patients experience blood pressure instability. We think this is a viable therapeutic, and the first therapeutic for people with spinal cord injury ever.” Phillips’ findings are a milestone for Canadian neuroscience and emphasize how discovery-based research can lead to therapies that give patients new hope.

Watch: Research studies say implant can regulate blood pressure in spinal cord injuries

 Aaron Phillips is the associate dean (Innovation and Commercialization) and an associate professor in the departments of Clinical Neurosciences, Physiology and Pharmacology, and Cardiac Sciences at the Cumming School of Medicine (CSM). He is a member of the Hotchkiss Brain Institute (HBI) and Libin Cardiovascular Institute, at the CSM and director of RESTORE Network. He was awarded a $100,000 Future Leaders in Canadian Brain Research grant in 2019 to support the project: Neuroprosthetic-mediated rehabilitation of autonomic function after spinal cord injury. The grant was made possible with the financial support of Health Canada (through the Canada Brain Research Fund, an innovative partnership between the Government of Canada (through Health Canada) and Brain Canada) and an anchor gift from the Azrieli Foundation for the Future Leaders program.