Three rats paralyzed due to spinal ischemia returned to near normal ambulatory function six weeks after having received human spinal stem cells (hSSCs) developed by Neuralstem, Inc., researchers reported online in the journal Neuroscience.
Three other rats, while not able to stand up two months after treatment, showed significant improvement in the mobility of all three lower extremity joints and increased muscle tone.
In all the grafted animals, the majority of transplanted hSSCs cells survived and became mature neurons. The study was conducted at the University of California at San Diego.
The rats suffered from Ischemic Spastic Paraplegia (ISP), a painful form of extreme spasticity and rigidity that causes permanent and untreatable loss of motor function and paralysis.
In humans, ISP can result from surgery to repair aortic aneurysms, an operation that is performed on thousands of patients a year in the United States.
"Other human stem cell transplants in the spinal cord have focused on repairing the myelin-forming cells," commented Dr. Karl Johe, Neuralstem Founding Scientist, and a study author. "In this breakthrough study, we are reconstructing the neural circuitry, which has not been done before. This novel approach is one for which our technology, which generates highly neurogenic human stem cell lines, is uniquely suited."
Dr. Johe went on to say, "Human ISP patients, unlike the rat subjects of this study, will be able to receive physical therapy once treated. We believe this will accelerate integration of the grafted stem cells with the host tissue and enhance the therapeutic benefit of the cells. The goal is to provide a significant gain in functional mobility of the patient's legs."
According to lead investigator Dr. Martin Marsala, "In this study, we demonstrated that grafting human neural cells directly into the spinal cord leads to a progressive recovery of motor function. This could be an effective treatment for patients suffering from the same kind of ischemia-induced paralysis. We are currently studying hSSCs in paralyzed mini-pigs, who have similar spinal cord anatomy as human spinal cords."
According to Neuralstem CEO, Richard Garr, "Neuralstem is a second generation stem cell company, built primarily to optimize our discovery of neural stem cells, and take them into the clinic and into patients. We believe, as this study demonstrates, that our technology answers many of the issues that have held the field back, and makes it possible to build a stem cell company around a true product focus. We expect to file an IND for our first human trial to treat paraplegic patients in 2007," he concluded.