Newborn Neurons May Promote Stroke Recovery in Humans

Newswise — It appears the human brain attempts to heal itself by giving birth to new neurons following a stroke. This finding, by scientists at the Buck Institute for Age Research, confirms similar studies in animal models and offers new targets for therapeutics to aid stroke recovery. The research is to be published the week of August 21st in the Proceedings of the National Academy of Sciences (PNAS).

Although neurogenesis, or the birth of new brain cells, is fairly rare in the adult brain, this process is turned on after certain types of injury. Neurogenesis has been observed in animal models of stroke. But because of the difficulty of detecting the process in humans, its role in stroke recovery has remained unclear. Lead scientist, David Greenberg, MD, PhD, and Kunlin Jin, MD, PhD, and their team addressed this issue by looking for newborn neurons in human brain biopsies taken from patients with stroke. The researchers found that cells surrounding the stroke-damaged area carried molecular markers of neurogenesis. In addition, the newborn cells were predominantly located near blood vessels, which have been shown to produce factors that boost cell division and growth.

Strokes, which usually result from a blockage in a cerebral artery, are among the most common causes of death and disability in adults. Approximately 700,000 Americans experience a new or recurrent stroke every year, accounting for one out of every 15 deaths in this country. The fact that many patients improve in the weeks to months following a stroke, implies an innate capacity for brain repair.

"We observed cells that produced proteins characteristic of neurons, had normal nuclei, and were of a type that migrate to new sites," said Greenberg. "The fact that several drugs have stimulated new nerve growth in rodents, suggests that clinical interventions might be developed to enhance this process in humans."

The next step in the research is to continue studies on rodents to determine if the newborn neurons that appear following stroke function normally, and how their production can be maximized. The need for further research is made more urgent based on a recent study which set a national price tag of $2.2 trillion for the care of those suffering from stroke over the next 45 years.

Joining Greenberg and Jin as co-authors of the paper are Buck Institute scientists Lin Xie, MS; Xiao Ou Mao, MD, and Surita Banwait, BS, along with Xiaomei Wang, Wei Zhu, and Yin Wang from Huashan Hospital, Fudan University, Shanghai, China; and Jianfeng Shen from First Affiliated Hospital, Zhejiang Medical University, Zhejiang, China. The work was supported by National Institutes of Health grants AG21980 and NS44921 and by the National Science Foundation of China grant 30472005.

The Buck Institute is the only freestanding institute in the United States that is devoted solely to basic research on aging and age-associated disease. The Institute is an independent nonprofit organization dedicated to extending the healthspan, the healthy years of each individual's life. The National Institute of Aging designated the Buck a "Nathan Shock Center of Excellence in the Biology of Aging," one of just five centers in the country. Buck Institute scientists work in an innovative, interdisciplinary setting to understand the mechanisms of aging and to discover new ways of detecting, preventing and treating conditions such as Alzheimer's and Parkinson's disease, cancer, arthritis and stroke. Collaborative research at the Institute is supported by new developments in genomics, proteomics and bioinformatics technology. For more information: www.buckinstitute.org.