Type 2 Diabetes may be linked to the buildup of protein tangles or tau in the brain independently of Alzheimer’s disease, according to new research.
The study appears in the Sept. 2 online edition of Neurology, the journal of the American Academy of Neurology.
“Evidence shows that people with type 2 diabetes have double the risk of developing dementia,” study author Velandai Srikanth, MD, PhD, from Monash University in Melbourne, Australia, said in a press release from the American Academy of Neurology. “This interesting development further defines how the diseases may be connected.”
Tangles and plaques formed by abnormal proteins in the brain and spinal fluid are one of the hallmark symptoms of Alzheimer’s.
For the study, researchers followed 816 people, average age about 74. Among the participants, 397 had mild cognitive impairment, which can be a precursor to dementia; 191 had Alzheimer’s disease and 228 people had no memory or thinking problems. A total of 124 of the participants had diabetes.
Researchers looked at the relationship between Type 2 Diabetes and the loss of brain cells and their connections, levels of beta amyloid (a sticky buildup of plaques) and tau or tangles of protein in participants’ spinal fluid.
They found that people with diabetes had higher levels of the tau protein in the brains and spinal fluid regardless of whether they showed any signs of Alzheimer’s or cognitive impairment.
Higher levels of tau in spinal fluid may indicate a higher buildup of tangles in the brain. Eventually, the development of those tangles may contribute to the development of Alzheimer’s disease.
Srikanth and his colleagues also found the cortex – the layer of brain tissue with the highest number of nerve cells – was thinner in diabetics than non-diabetics, also regardless of any sign of cognitive impairment or Alzheimer’s. The buildup of tangles might contribute to the loss of cortex tissue.
“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,” Srikanth said.
Srikanth stressed that because the study looked at participants’ data at one point in time, it does not determine whether there is a cause-and-effect relationship between diabetes and the brain tangles.
