Hibernating ground squirrels provide clues to new stroke treatments

Friday, November 17, 2017

Multi-step screening process leads to molecule that may protect brain cells.

In the fight against brain damage caused by stroke, researchers have turned to an unlikely source of inspiration: hibernating ground squirrels.

While the animals’ brains experience dramatically reduced blood flow during hibernation, just like human patients after a certain type of stroke, the squirrels emerge from their extended naps suffering no ill effects. Now, a team of NIH-funded scientists has identified a potential drug that could grant the same resilience to the brains of ischemic stroke patients by mimicking the cellular changes that protect the brains of those animals.

An ischemic stroke occurs when a clot cuts off blood flow to part of the brain, depriving those cells of oxygen and nutrients like the blood sugar glucose that they need to survive. Nearly 800,000 Americans experience a stroke every year and 87 percent of those are ischemic strokes.

Currently, the only way to minimize stroke-induced cell death is to remove the clot as soon as possible. A treatment to help brain cells survive a stroke-induced lack of oxygen and glucose could dramatically improve patient outcomes, but no such neuroprotective agents for stroke patients exist.

Recently, researchers led by John Hallenbeck, M.D., an NINDS senior investigator and co-senior author of the study, found that a cellular process called SUMOylation goes into overdrive in a certain species of ground squirrel during hibernation. Dr. Hallenbeck suspected this was how the animals’ brains survived the reduced blood flow caused by hibernation, and subsequent experiments in cells and mice confirmed his suspicions.