A growth hormone frequently prescribed for cancer patients has been found to significantly reduce memory loss from Alzheimers disease. The drug, which stimulates the production of red blood cells, essentially washes plaques out of the brain.
Plaques are protein buildups (pictured) found in the brains of people suffering from age-related dementia, and are believed to be related to memory loss and other symptoms of Alzheimers. These can be signifcantly reduced if patients take drugs containing granulocyte-colony stimulating factor (GCSF), a human hormone that stimulates stem cells in bone marrow to produce more red blood cells. Scientists at University of South Florida and James A. Haley Hospital discovered in tests on mice that the surge in new blood cells acts as a purging agent, washing through the brain and cleansing neurons "clogged" by protein buildup. There was ultimately a 32-40 percent reduction in this dementia-causing protein, known as beta amyloid, in the mouse brains.
A release from the University of South Florida reports:
The researchers showed that injections under the skin of filgrastim [marketed as the proprietary drug Neupogen] — one of three commercially available GCSF compounds — mobilized blood stem cells in the bone marrow and neural stem cells within the brain and both of these actions led to improved memory and learning behavior in the Alzheimer's mice. "The beauty in this less invasive approach is that it obviates the need for neurosurgery to transplant stem cells into the brain," Dr. Sanchez-Ramos said.
Based on the promising findings in mice, the Alzheimer's Drug Discovery Foundation is funding a pilot clinical trial at USF's Byrd Alzheimer's Center.
So the testing in humans is about to begin.
How does GCSF work? Continues the release:
GCSF reduced the burden of beta amyloid deposited in the brains of the Alzheimer's mice by several means, the researchers found. One was by recruiting reinforcements to clear beta amyloid accumulating abnormally in the brain. The growth factor prodded bone-marrow derived microglia outside the brain to join forces with the brain's already-activated microglia in eliminating the Alzheimer's protein from the brain. Microglia are brain cells that act as the central nervous system's main form of immune defense. Like molecular "Pac-men," they rush to the defense of damaged or inflamed areas to gobble up toxic substances.
The growth factor also appeared to increase the production of new neurons in the area of the brain (hippocampus) associated with memory decline in Alzheimer's disease and to form new neural connections.
This is seriously great news. It means we can have stem cell treatments that don't involve injecting new stem cells into the body - you can just stimulate production in your already-existing stem cells. It also means that we may have figured out a way to help people grow new neurons - a golden ring of neuroscience - with an already-existing drug. Can't wait to see how the next round of tests come out in human subjects.