A new study shows that transplanting the bone marrow of younger laboratory mice into old mice could effectively prevent cognitive decline, a finding that scientists expect to lead the development of new treatments to delay the effects of aging in people. Researchers found that the younger bone marrow helped preserve the memory and learning abilities of old mice, EurekAlert reported. “While prior studies have shown that introducing blood from young mice can reverse cognitive decline in old mice, it is not well understood how this happens,” said Helen Goodridge, associate professor of Medicine and Biomedical Sciences at Cedars-Sinai and co-senior author of the study. “Our research suggests one answer lies in specific properties of youthful blood cells,” she added. If applied in humans, the team believes that the process could help design new therapies to slow the progression of neurodegenerative diseases, including Alzheimer's disease. For the study, published in the journal Communications Biology, researchers transplanted a bone marrow from four-month-old mice into 18-month-old laboratory subjects. Six months after the procedure, those that received young bone marrow outperformed mice that did not get a transplant during lab tests focused on learning and spatial and working memory. The hippocampus, a brain region associated with memory, also appeared with more connections in mice with transplanted bone marrow. Researchers said that young blood cells reduced the activation of a type of immune cell, called microglia, in the brain, which led neurons to remain healthy. Microglia is known to contribute to disconnection of synapses or connections in the brain. “Our work indicates that cognitive decline in mice can be significantly reduced by simply providing young blood cells, which act on the brain to reduce the loss of synapses related to aging,” said Clive Svendsen, director of the Cedars-Sinai Board of Governors Regenerative Medicine Institute and co-senior author of the study. He added that the findings come amid the growing number of older people with Alzheimer's disease. Svendsen and his team aim to confirm the findings with humans in the future. The researchers intend to use stem cell technology to replace an individual's aging blood cells and prevent cognitive decline or neurodegenerative diseases. Source
