Injections of a natural growth factor into the brains of mice, rats and monkeys offers hope of preventing or reversing the earliest impacts of Alzheimer鈥檚 disease on memory. The benefits arose even in animals whose brains contained the hallmark plaques that clog up the brains of patients.
By delivering brain-derived neurotrophic factor (BDNF) directly into the entorhinal cortex and hippocampus, the parts of the brain where memories are formed then consolidated, the researchers successfully tackled damage exactly where Alzheimer鈥檚 strikes first.
鈥淲e鈥檙e administering BDNF directly to the degenerating neurons in memory systems of the cortex, and preventing their death,鈥� says of the University of California at San Diego. The substance, which naturally supports brain cells throughout life, also amplified the numbers of connections, or synapses, between neurons.
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鈥淥ur most compelling evidence was the observation that brain cell death was prevented, and that connections between neurons rose in density by about 25%,鈥� says Tuszynski. Improvements on this scale happened in all the animals, including mice with a version of human Alzheimer鈥檚 disease, elderly rats and monkeys with natural degeneration, plus rats and monkeys given brain lesions similar to those seen in Alzheimer鈥檚.
To prolong the effects beyond simply injecting BDNF itself, Tuszynski injected a harmless lentivirus carrying the gene for BDNF, so that the chemical would carry on being produced by the virus. He says that pending safety studies, trials could start in two years.
Charles Harrington of , a company in Aberdeen, UK, developing a drug for Alzheimer鈥檚 called Rember, questions whether such an invasive treatment would be safe and practical. Also, he says that if the treatment doesn鈥檛 block the tau protein tangles that accumulate in neurons of Alzheimer鈥檚 patients, the disease might advance even if cells survive and form connections to others.
Journal reference: , (in press)
