Spinal cord injury patients obviously have to deal with the loss of function, but another, less obvious problem many of these patients have is unstable blood pressure. Researchers have now created a treatment that addresses this blood pressure issue and could help these patients significantly. The work has been reported in Nature.
"A serious and underrecognized result of [spinal cord] injuries is unstable blood pressure, which can have devastating consequences that reduce quality of life and are life-threatening. Unfortunately, there are no effective therapies for unstable blood pressure after spinal cord injury," said the co-lead study author Dr. Aaron Phillips of the University of Calgary. "We created the first platform to understand the mechanisms underlying blood pressure instability after spinal cord injury."
Several paraplegics have been able to walk again after being given epidural electrical stimulation (EES), in which electrical stimulation is applied directly to the lower part of the spinal cord. But researchers still don't really know how EES works.
In this study, the researchers targeted neural circuits that are involved in the regulation of blood pressure using animal models. They took measurements with an implanted blood pressure monitor during the procedure so that modifications could be made in real-time. The monitor reads blood pressure continuously and can use the reads to alter the settings of a pacemaker that delivers the electrical stimulus to the spinal cord. The procedure is meant to mimic the natural activity of the body.
"The stimulation compensates for the broken communication line between the patient's central nervous system and sympathetic nervous system," explained the study co-leader Grégoire Courtine of EPFL.
"It was impressive to see the blood pressure rise to the target level immediately after the stimulation was applied," noted Jocelyne Bloch, the neurosurgeon who heads the NeuroRestore research center with Courtine.
The method was tested on a human patient after it worked in the animal models. That patient is Dr. Richi Gill, M.D., who now no longer needs to take medication to control his blood pressure. He was paralyzed after breaking his neck in a boogie board accident while on a family vacation three years ago.
“What many people don’t realize is that a spinal cord injury prevents some systems within the body from regulating automatically. My blood pressure would drop drastically, leaving me fatigued, dizzy, and unable to focus. The condition can be life-threatening, requiring medication for life,” said Richi.
"Those daily episodes of hypotension were a real burden. They also disturbed my vision and prevented me from performing even simple everyday tasks. The electrical stimulation treatment provided a huge relief - much more effective than medication."