A drug commonly used to treat type 2 diabetes may reduce excess fluid in the brains of patients with hydrocephalus, which could help treat the disease less invasively than current treatments, according to a Northwestern Medicine study published in the Journal of Clinical Investigation.
Stephen Magill, MD, PhD, assistant professor of Neurological Surgery, was senior author of the study.
Normal pressure hydrocephalus occurs when excess cerebrospinal fluid builds up inside the skull and puts pressure on the brain. The cause of the condition is elusive and affects up to three percent of individuals over the age of 65, with symptoms including cognitive decline, difficulty walking and bladder problems.
Patients are typically treated with permanent ventriculoperitoneal shunts, which are surgically implanted in the front or back of the skull and are connected to a valve that diverts excess cerebrospinal fluid away from the brain and into the abdomen where it is absorbed. The procedure has been shown to dramatically improve mobility, bladder control and cognitive functioning in patients with hydrocephalus, according to Magill.
“It’s a great procedure because it’s one of the few things you can do that actually reverses these symptoms,” Magill said.
There is, however, no pharmacological treatment currently approved to treat hydrocephalus. Additionally, nearly 20 percent of patients with normal pressure hydrocephalus also have type 2 diabetes and take sodium/glucose cotransporter 2 (SGLT2) inhibitors to manage their blood sugar, cardiovascular and kidney function, and weight loss.
Magill recently observed a reduction in the brain ventricle size in a patient with hydrocephalus who had a ventriculoperitoneal shunt surgically implanted and then began taking SGLT2 inhibitors to treat their type 2 diabetes. This phenomenon prompted Magill to further investigate the impact of SGLT2 inhibitors on ventricular size in patients with hydrocephalus.
“The medication inhibits a receptor found in the kidneys, which is where it works for diabetes. However, that receptor is also expressed in the choroid plexus, which is the structure in the brain that secretes the spinal fluid. Although this was known from animal studies, the clinical aspects of this biology have not been fully appreciated,” Magill said.
In the current study, three patients with hydrocephalus underwent CT scans both before and after surgery for ventriculoperitoneal shunts. After surgery, each patient began taking SGLT2 inhibitors for a medical indication and then underwent additional CT scans.
From analyzing these scans, Magill’s team discovered that all three patients showed a reduction in ventricle size as well as structural changes in their brains after starting SGLT2 therapy. One patient demonstrated dramatic ventricle size reduction due to ventricular collapse and required a shunt valve adjustment to reduce cerebrospinal fluid drainage.
“It’s a really interesting clinical observation because it raises the possibility that these medications could be used to treat normal pressure hydrocephalus in the future, which would normally require surgery,” Magill said.
Magill said the findings have sparked a new line of research in studying how SGLT2 inhibitors could help prevent hydrocephalus, adding that his team is now studying SGLT2 knockout mouse models to better understand the drug’s impact on ventricular size.
Their findings could ultimately inform new therapeutic strategies for treating normal pressure hydrocephalus as well as post-traumatic hydrocephalus, or the buildup of cerebrospinal fluid after traumatic brain injury, according to Magill.
“This sparks a new line of research on how normal pressured hydrocephalus develops, what causes it, how this protein works in creating and secreting spinal fluid, and has direct translational implications,” Magill said. “There’s a whole new avenue of potentially treating this disease that might save a patient from having surgery, and there’s always risks with surgery. It will also evolve our understanding of how these drugs work.”
Nishanth Sadagopan and Rushmin Khazanchi, both third-year medical students, were co-first authors of the study.
Co-authors of the study include Rishi Jain, a second-year medical student, and Amy Heimberger, MD, PhD, the Jean Malnati Miller Professor of Brain Tumor Research and vice chair for research in the Department of Neurological Surgery.
