How human neural stem cells alleviate 'chemobrain' post chemotherapy

Scientists have explained how human neural stem cells repair cognitive function after cancer treatments.

According to UC Irvine researchers, stem cell treatments are showing promise for reversing learning and memory deficits after chemotherapy.

In preclinical studies using rodents, they found that stem cells transplanted one week after the completion of a series of chemotherapy sessions restored a range of cognitive functions, as measured one month later using a comprehensive platform of behavioral testing. In contrast, rats not treated with stem cells showed significant learning and memory impairment.

The frequent use of chemotherapy to combat multiple cancers could produce severe cognitive dysfunction, often referred to as "chemobrain," which can persist and manifest in many ways long after the end of treatments in as many as 75 percent of survivors - a problem of particular concern with pediatric patients.

Charles Limoli, a UCI professor of radiation oncology, said that the findings provide the first solid evidence that transplantation of human neural stem cells can be used to reverse chemotherapeutic-induced damage of healthy tissue in the brain.

For the study, adult neural stem cells were transplanted into the brains of rats after chemotherapy. They migrated throughout the hippocampus, where they survived and differentiated into multiple neural cell types. Additionally, these cells triggered the secretion of neurotrophic growth factors that helped rebuild wounded neurons.

Importantly, Limoli and his colleagues found that engrafted cells protected the host neurons, thereby preventing the loss or promoting the repair of damaged neurons and their finer structural elements, referred to as dendritic spines.

The study suggests that stem cell therapies may one day be implemented in the clinic to provide relief to patients suffering from cognitive impairments incurred as a result of their cancer treatments, Limoli said.

The results appear in the journal Cancer Research.