The cholesterol-lowering drug simvastatin appears to reduce spinal cord injury caused by oxygen deprivation in experimental animals, according to a study in the September issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society (IARS).
With further research, treatment with statin drugs might provide a new approach to lowering the risk of paraplegia as a complication of surgery involving the aorta, the new research suggests. The experimental study was led by Takeshi Saito, Ph.D., of Nigata University Graduate School of Medical and Dental Sciences, Japan.
The researchers used a standard technique to produce spinal cord damage due to oxygen deprivation in laboratory rats. This technique simulates a serious complication that can occur in patients undergoing major surgery involving the aorta, such as surgery to repair an aortic aneurysm. In this situation, temporary interruption of blood supply (ischemia/reperfusion injury) can lead to spinal cord injury and paraplegia.
In the experiments, rats received either simvastatin or an inactive treatment for one week before interruption of blood supply to the spinal cord, plus an additional dose 24 hours after blood flow was restored. Signs of spinal cord damage and paraplegia were compared between the two groups.
After 24 and 48 hours, movement of the rear limbs was significantly better in rats treated with simvastatin. The limb motion abnormality caused by ischemia/reperfusion injury was reduced by about half in statin-treated animals, compared to those receiving inactive treatment.
Follow-up examination of spinal cord specimens showed less cellular damage in the simvastatin group.
Spinal cord damage resulting in paraplegia is a potential risk of aortic surgery. Several different strategies have been tried to prevent this devastating complication, with limited success.
Recent studies have suggested that statin drugs —widely used to lower cholesterol levels—can protect the brain from damage caused by oxygen deprivation. This raises the possibility that statins might have a similar "neuroprotective" effect against spinal cord damage caused by ischemia/reperfusion injury.
The new experiments suggest that simvastatin protects against spinal cord damage caused by ischemia/reperfusion injury in rats, in a situation similar to that caused by aortic surgery in humans. It's unclear exactly how simvastatin exerts its neuroprotective effect—possibly through suppression of harmful substances released in response to oxygen deprivation. More research will be needed to see if statin drugs have any protective effect against spinal cord injury and paraplegia in patients undergoing aortic surgery.
"Spinal cord injury is among the most devastating complications of major vascular surgery," comments Dr. Steven L. Shafer of Columbia University, Editor-in-Chief of Anesthesia & Analgesia. "Although this result is very preliminary, it opens up a new approach to cord protection. If the result is reproducible in larger animals, then clinical trials should be conducted to establish safety and efficacy for patients undergoing aortic repair."