MEMORY PROBLEMS are an early sign of Alzheimer's. New research directly links these problems to sugar (glucose) deprivation in brain cells. In diabetes, a well-known Alzheimer's risk factor, sugar is blocked from entering cells. How likely does this make the Alzheimer's-sugar-diabetes triangle?
(Philadelphia, PA) – One of the earliest signs of Alzheimer's disease is a decline in glucose levels in the brain. It appears in the early stages of mild cognitive impairment — before symptoms of memory problems begin to surface. Whether it is a cause or consequence of neurological dysfunction has been unclear, but new research at the Lewis Katz School of Medicine at Temple University now shows unequivocally that glucose deprivation in the brain triggers the onset of cognitive decline, memory impairment in particular.
As diabetes is a condition in which glucose cannot enter the cell, this research gives good reason to suggest that Alzheimer's is caused by a pathway similar or related to a type of diabetes. This possibility is strengthened by the fact that insulin resistance in type 2 diabetes is a known risk factor for dementia.
“In recent years, advances in imaging techniques, especially positron emission tomography (PET), have allowed researchers to look for subtle changes in the brains of patients with different degrees of cognitive impairment,” explained Domenico Praticò, MD, Professor in the Center for Translational Medicine at the Lewis Katz School of Medicine at Temple University (LKSOM). “One of the changes that has been consistently reported is a decrease in glucose availability in the hippocampus.”
The hippocampus plays a key role in processing and storing memories. It and other regions of the brain, however, rely exclusively on glucose for fuel — without glucose, neurons starve and eventually die.
The new study, published online January 31 in the journal Translational Psychiatry, is the first to directly link memory impairment to glucose deprivation in the brain specifically through a mechanism involving the accumulation of a protein known as phosphorylated tau.