Alzheimer’s breakthrough: A world-first study from Edith Cowan University (ECU) has confirmed the genetic link between suffering from disorders of the gastrointestinal tract and an increased risk of developing Alzheimer’s disease (AD). A finding that could lead to earlier detection and potential new treatments for both problems.
Alzheimer’s destroys memory and thinking ability and is the most common form of dementia. It has no known curative treatments and it is estimated that it will affect more than 82 million people by 2030. Previous observational studies have suggested a relationship between this type of dementia and disorders of the gastrointestinal tract, but until now it was not clear what underlies these relationships.
The ECU Precision Health Center has now provided new insights into these relationships by confirming a genetic link between Alzheimer’s Disease and multiple intestinal disorders. The study, published in Communications Biology, analyzed large genetic data sets from Alzheimer’s patients and several studies of intestinal disorders, each involving about 400,000 people.
Research leader Dr. Emmanuel Adewuyi said it was the first comprehensive assessment of the genetic link between Alzheimer’s and multiple bowel disorders. The team found that people with Alzheimer’s and intestinal disorders have genes in common, which is important for many reasons. “The study provides novel insight into the genetics behind the observed co-occurrence of Alzheimer’s and intestinal disorders,” said Dr. Adewuyi. “This improves our understanding of the causes of these conditions and identifies new targets for investigation to potentially detect disease earlier and develop new treatments for both types of conditions.”
The findings reveal significant positive genetic overlap and correlation between AD and gastroesophageal reflux disease (GERD), peptic ulcer disease (PUD), gastritis-duodenitis, irritable bowel syndrome, and diverticulosis, but not with inflammatory bowel disease.
Director of the Center for Precision Health and supervisor of the study, Professor Simon Laws, said that while the study did not conclude that intestinal disorders cause Alzheimer’s disease or vice versa, the results are immensely valuable. “These findings provide additional 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 gut,” said Professor Laws.
Is cholesterol a key to treating Alzheimer’s?
When the researchers looked further into shared genetics, they found other important links between Alzheimer’s disease and intestinal disorders, such as the role that cholesterol may play. Thus, Dr. Adewuyi notes that abnormal cholesterol levels have been shown to be a risk for both Alzheimer’s disease and intestinal disorders.
“Looking at the genetic and biological features common to AD and these intestinal disorders suggests an important role for lipid metabolism, the immune system and cholesterol-lowering drugs,” he said.
“While more study is needed on shared mechanisms between the conditions, there is evidence that high cholesterol can be transferred to the central nervous system, resulting in abnormal cholesterol metabolism in the brain.” He continues, “There is also evidence to suggest that abnormal blood lipids may be caused or worsened by intestinal bacteria (H. pylori), all of which support potential roles for abnormal lipids in AD and intestinal disorders.” . thus, for example, “elevated cholesterol in the brain has been linked to brain degeneration and subsequent cognitive decline.”
Statins, hope for the future
The cholesterol link could prove vital in the treatment of Alzheimer’s disease in the future. And, although there are currently no known curative treatments, the study findings suggest that cholesterol-lowering drugs (statins) could be therapeutically beneficial to treat both AD and intestinal disorders.
“Evidence indicates that statins have properties that help reduce inflammation, modulate immunity, and protect the gut,” suggests Dr. Adewuyi. However, being cautious, he reminds that more studies were needed in this regard and that patients should be evaluated individually to judge if they would benefit from the use of statins.
The research also indicated that diet could play a role in the treatment and prevention of Alzheimer’s disease and intestinal disorders.
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