ShareThisIs Alzheimer's really a disease to be cured, like cancer, or is it a product of aging -- a form of degeneration that affects just about everybody as they get older?
Researchers have been defining Alzheimer's as a disease distinct from the aging process, says Ming Chen, a University of South Florida professor of molecular pharmacology and physiology. He believes this approach obscures the fact that the risk of dementia increases with age, which suggests it can only be postponed, like heart disease, but never really cured.
"To researchers, Alzheimer's disease connotes a discrete disease," said Chen. "Thus, over 90 percent of the Alzheimer's studies funded by the National Institutes of Health are on mutations, toxic amyloid (beta peptides), pathogens, and so on. And that is why after three decades and billions of dollars spent, more than 90,000 research papers published, and numerous great breakthroughs claimed, the condition remains a persistent enigma."
Chen is the co-author of two articles in the Journal of Alzheimer's Disease's December issue that encourage scientists to stop searching for "silver bullets" to eradicate the disease, and to focus instead on finding ways to modify the disease process through lifestyle changes and perhaps medication.
The first case of Alzheimer's disease, diagnosed by Alois Alzheimer in 1906, involved a 51-year-old woman who developed a rapidly progressing form of dementia. Alzheimer attributed it to the clumps of amyloid protein he spotted between her neurons when he examined them under the microscope after her death, and the tangles of tau protein he saw within her neurons.
Since then, Alzheimer's disease has been viewed as a single disease. But the dementia that the woman developed at an early age might have differed significantly from the brain degeneration that becomes increasingly common with age. For many years, Alzheimer's disease was considered "presenile" dementia, a form of brain degeneration taking place in middle age.
In recent years, this distinction has been lost as researchers have focused on ways to eradicate Alzheimer's pathology altogether.
But brain cells, like all other cells, become more frail and vulnerable to breakdown with age, Chen says. While this process, known as senescence, cannot be cured, diet, exercise, and certain medications may help postpone the inevitable.
But if dementia comes with age, why do some people in their 80s retain the mental acuity of people 30 years younger?
Researchers in Chicago are trying to answer that question by studying "SuperAgers," a diverse group of older people whose brains appear to defy the ravages of time.
The biggest difference they've found so far in the SuperAgers involves brain shrinkage, which occurs in virtually everyone with age. Over time, neurons die, and the fatty white myelin that wraps around the brain's transmission fibers becomes thinner, leaving the brain smaller.
The SuperAgers, according to Emily Rogalski, who is leading the study, show virtually no "cortical shrinkage," as she calls it. By conducting MRI scans, she and her colleagues at Northwestern University's Feinberg School of Medicine even found that one part of the brain implicated in Alzheimer's disease, the anterior cingulate, was thicker in some of the SuperAgers.
Remember those plaques and tangles that Alzheimer found in his demented patient's brain? The brains of some SuperAgers are riddled with them, even though their cognition appears to be much better than normal for their age. Those familiar hallmarks of Alzheimer's disease, which researchers have spent so much time, energy, and money trying to eradicate, don't seem to affect the SuperAgers at all.
"Why?" Rogalski asks. "There has to be a reason for this."
(Contact Tom Valeo at tom.valeo(at)gmail.com. For more stories visit scrippsnews.com.)
Must credit Tampa Bay Times.
