When injured, the spinal cord swells, restricting blood flow and causing critical and permanent motor, sensory, and autonomic function damage. Rapid prevention of spinal cord swelling immediately after injury is key to preventing more serious damage. The only treatment to date has been steroid therapy with methylprednisolone, which is minimally effective.

Now a group led by Marlan and Rosemary Bourns College of Engineering Professor Jacques S. Yeager, Sr. Professor of Bioengineering Victor G. J. Rodgers, and UCR School of Medicine Professor of Biomedical Sciences Devin Binder  have created an osmotic therapy device that gently removes fluid from the spinal cord to reduce swelling in injured rats with good results. The device can eventually be scaled up for testing in humans. Their research appears in an open-access paper published in Frontiers in Bioengineering and Biotechnology.

The device consists of a tangential flow module supporting a semipermeable membrane connected to a hydrogel that rests on the exposed spinal cord. Artificial cerebrospinal fluid containing the protein albumin to initiate osmosis passes across the device side of the membrane, transporting water molecules from the spinal cord. Both fluids drain into a small chamber and cycle again through the device to remove more water. The amount of water removed is small compared to the amount of osmolyte, allowing for recirculation.

The authors have found in previous studies that relatively small increases in the percent of water content can cause significant swelling in the brain. These experiments showed the osmotic therapy device removed enough water to prevent brain swelling and was capable of removing even more. They also found that removing the excess water quickly enough in brain swelling improved neurological outcomes. This is a key hope for the spinal cord device as well.

The team plans to continue improving the device through longer experiments on rats before eventually moving on to human trials. 

Rodgers and biomedical sciences professor Byron Ford are developing a similar device that drains fluid directly from the brain and introduces neuregulin-1, a molecule produced naturally by the body to regulate communication between cells in the brain and heart, promoting their growth, in order to reduce damage of severe strokes.

The paper, “Implantable osmotic transport device can reduce edema after severe contusion spinal cord injury,” is available here. Other authors include Christopher Hale, Jennifer Yonan, Ramsey Batarseh, Roman Chaar, Carrie R. Jonak, and Shaokui Ge, all of whom are also at UC Riverside.

^{Header photo by Hanna Postova on Unsplash}