FRIDAY, November 2, 2018 – Alzheimer's patients taking diabetes medications may have fewer signs of brain dementia than comparable patients who are not taking the medication.
In particular, the post-mortem study found that people who took diabetes medications had fewer abnormalities in tiny blood vessels in their brains and less abnormal gene activity.
"The results of this study are important because they provide us with new insights into the treatment of Alzheimer's disease," said lead author of the study, Vahram Haroutunian, a professor of psychiatry and neuroscience at the Icahn School of Medicine at Mount Sinai in New York City.
Earlier studies on brain tissue showed that the brain of people with Alzheimer's and diabetes had fewer Alzheimer's lesions than the brain of people with Alzheimer's without diabetes.
An Alzheimer's expert said the study highlights the relationship between cardiovascular and brain health.
The results "remind us of the importance of keeping vascular risk factors under control as we grow older," said Drs. Luca Giliberto. He is Assistant Professor at the Litwin Sugar Center for Alzheimer's Disease and Memory Disorders at the Feinstein Institute for Medical Research in Manhasset, New York.
In the new study, conducted with autopsied brains, Haroutunian and his colleagues developed a way to separate the tiny blood vessels called capillaries in the brain from neighboring brain tissue.
They first used this method in 34 people diagnosed with Alzheimer's and Type 2 diabetes treated with standard diabetes medications.
The researchers then compared these findings with a study of 30 brains of Alzheimer's patients who did not have diabetes and 19 brains of people who did not have any disease.
The study focused on changes in certain genetic "markers" that were closely linked to proper brain signaling.
According to the researchers, approximately half of these markers were lower in the vessels and brain tissue of patients with both Alzheimer's and diabetes. And the majority of the unhealthy genetic changes normally seen in Alzheimer's were missing in patients taking diabetes medication.
All this suggests that diabetes medications have a protective effect on the brains of Alzheimer's patients, the researchers said, which in turn could boost the search for effective therapies.
"Most modern Alzheimer's treatments target amyloid plaques and have failed to treat the disease effectively," Haroutunian said in a Mount Sinai press release.
However, the new study focused on "insulin and diabetes medications such as metformin, [which are] FDA approved and safely administered to millions of people, "he said.
The new study suggests that these drugs "have a positive effect on people with Alzheimer's disease," Haroutunian said. "This opens up the opportunity to conduct research studies on people who are taking similar medicines or medicines that have similar effects on the brain's biological pathways and cell types identified in this study."
Giliberto said the results were "not surprising" as experts have long identified correlations between the effects of diabetes on blood sugar and blood vessel health and brain health.
However, he added that the study does not prove that these problems cause Alzheimer's disease or that diabetes medications can stem or stop the brain-wasting disease once it's started.
"The treatment of chronic hyperglycemia, however, leads to a reduction in other brain damage," argued Giliberto. For people with Alzheimer's disease, this could "lead to better cognitive performance and quality of life," he said.
Dr. Satjit Bhusri is a cardiologist at Lenox Hill Hospital in New York City. In reviewing the study, he said it "establishes a relationship between the blood vessels of the brain and Alzheimer's disease".
The findings could "open the door to a new pathway that could be of therapeutic benefit to patients with Alzheimer's disease," Bhusri said.
The report was published online on November 1st in the journal PLOS One.
The Alzheimer's Association offers more on Alzheimer's disease.
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