The study investigated the relationship between type 2 diabetes, loss of brain cells, levels of beta amyloiod (plaques usually found in Alzheimer’s disease), and tau or tangles of protein in the brain and spinal fluids of research participants.
Tangles destroy a vital cell transport system made of proteins. In healthy brain areas the transport system is organized in orderly parallel strands somewhat like railroad tracks. Food molecules, cell parts and other key materials travel along the “tracks.”
A protein called tau (rhymes with wow) helps the tracks stay straight.
In areas where tangles are forming:
Tau collapses into twisted strands called tangles.
The tracks can no longer stay straight. They fall apart and disintegrate.
Nutrients and other essential supplies can no longer move through the cells, which eventually die.
The research participants consisted of 816 people; 397 had mild cognitive impairment, 191 had Alzheimer’s disease dementia, 124 participants had diabetes and 228 people had no memory and thinking problems.
“Evidence shows that people with type 2 diabetes have double the risk of developing dementia,” said study author Velandai Srikanth, MD, PhD, from Monash University in Melbourne, Australia. “This interesting development further defines how the diseases may be connected.”
People with diabetes had 16 picograms per milliliter greater levels of tau protein in the spinal and brain fluid. Tangles (linked to build up of tau protein) are linked to the development of dementia and Alzheimer’s disease. Diabetes is associated with a reduced thickness of cortex and the layer of the brain with most nerve cells.
Diabetic patients had cortical tissue that was an average of 0.03 millimeter less than those who did not have diabetes, whether they had no thinking and memory problems, mild cognitive impairment or dementia due to Alzheimer’s disease.
“Due to the fact that nerve cells in the brain do not replace themselves, it is extremely important to find ways to reduce the death of current brain cells. Studies such as ours seek to understand how diseases like diabetes may directly or indirectly affect brain cell death,” said Srikanth.