In a study recently published in the magazine Nature, a team of scientists led by Professor Karen H. Ashe from the University of Minnesota Medical School and the Minneapolis VA Medical Center in Minnesota and Professor Michela Gallagher at Johns Hopkins University, along with collaborators at University of Southern California and the University of California, Irvine, discovered a protein complex, which they named Ab*56 (amyloid beta star 56), that appears to impair memory.
People suffering from Alzheimer’s disease (AD) usually exhibit memory impairment that precedes clinical diagnosis or even prior to plaque formation in the brain or neurodegeneration when nerve cells in their brains begin to die (sometimes many years before). In search of a substance that might contribute to such early dementia, the researchers made use of a transgenic mouse model for AD and examined lab mice that showed signs of memory loss but had none of the known later symptoms of AD (amyloid plaque formation and neurodegeneration in the brain). They discovered accumulation of a soluble protein complex, Ab*56, which consists of 12 amyloid peptides or short proteins, whose appearance correlated with the early memory loss and whose amount correlated with the severity of dementia . They then extracted Ab*56 from the brains of those mice showing accumulation and injected the purified protein complex into the brains of healthy young rats, which were subsequently diagnosed with cognitive impairment and long-term memory loss, as measured by successive maze tests in which the rats must use what they learned a day earlier. Thus, the newly discovered protein complex indeed affects memory and cognitive abilities and might well play a significant role in the early development of AD.
According to the Alzheimer’s Association, there are currently about 4.5 million people living with AD in the U.S. alone. This number has more than doubled since 1980and is expected to continue to rise over the next decade and beyond. Although the new research is an important breakthrough, Dr. Ming-Teng Koh, a post doctoral fellow from Professor Gallagher’s lab at Johns Hopkins, told TFOT that: “More research is needed before we can comfortably speculate about the role of Ab*56 in humans, or the time frame needed to translate these findings into a commercial drug to stem memory loss.”