Alzheimer’s disease (AD) is the most prevalent form of dementia, characterized by neurodegeneration and a progressive decline in cognitive ability. Consistent with the concept of the gut-brain phenomenon, observational studies suggest a relationship between Alzheimer’s disease (AD) and gastrointestinal tract (GIT) disorders. However, what underpins these relationships has been unclear – until now.
A world-first Edith Cowan University (ECU) study has confirmed the link between the two, leading to earlier detection and new potential treatments. Scientists analyzed large sets of genetic data from AD and several gut-disorder studies – each of about 400,000 people. They found that people with Alzheimer’s and gut disorders have genes in common.
Research lead Dr. Emmanuel Adewuyi said, “It was the first comprehensive assessment of the genetic relationship between AD and multiple gut disorders. The study provides a novel insight into the genetics behind the observed co-occurrence of AD and gut disorders. This improves our understanding of the causes of these conditions and identifies new targets to investigate to detect the disease earlier and develop new treatments for both types of conditions.”
Centre for Precision Health director and study supervisor Professor Simon Laws said, “while the study didn’t conclude gut disorders cause AD or vice versa, the results are precious.”
“These findings provide further evidence to support the concept of the ‘gut-brain’ axis, a two-way link between the brain‘s cognitive and emotional centers, and the functioning of the intestines.”
Further analysis also revealed d other vital links between AD and gut disorders- such as the role cholesterol may play.
Dr. Adewuyi said abnormal cholesterol levels were a risk for both AD and gut disorders.
“Looking at the genetic and biological characteristics common to AD and these gut disorders suggests a strong role for lipids metabolism, the immune system, and cholesterol-lowering medications,” he said.
“While further study is needed into the shared mechanisms between the conditions, there is evidence high cholesterol can transfer into the central nervous system, resulting in abnormal cholesterol metabolism in the brain.”
“There is also evidence suggesting abnormal blood lipids may be caused or made worse by gut bacteria (H.pylori), all of which support the potential roles of abnormal lipids in AD and gut disorders.”
“For example, elevated cholesterol in the brain has been linked to brain degeneration and subsequent cognitive impairment.”
“Evidence indicates statins have properties which help reduce inflammation, modulate immunity, and protect the gut. However, there was a need for more studies, and patients needed to be assessed individually to judge whether they would benefit from statin use.”
Journal Reference:
- Adewuyi, E.O., O’Brien, E.K., Nyholt, D.R. et al. A large-scale genome-wide cross-trait analysis reveals shared genetic architecture between Alzheimer’s disease and gastrointestinal tract disorders. Commun Biology. DOI: 10.1038/s42003-022-03607-2