Authors: Alice Weatherston
Previous studies have indicated that an estimated 25% of cases of Alzheimer’s disease are influenced to some extent by poor diet and sedentary lifestyles. However, little is understood about the mechanisms of contribution of these lifestyle factors to subsequent cognitive function. Recent work by researchers at Tufts University (MA, USA)/The Jackson Laboratory, which was published in Nature Scientific Reports, has taken a closer look at these associations.
The researchers utilized a ‘western diet’ chow for mice developed by Simon John and his team (The Jackson Laboratory, ME, USA), which combines high amounts of animal products, fat and sugars with low plant-based content and nutrient density, mimicking a modern unhealthy western diet.
The chow was fed to healthy C57BL/6J mice and to APP/PS1 mice, which present some aspects of Alzheimer’s disease, for 8 months from 2 months of age which is almost the equivalent of late adolescence to early middle age in humans.
Results of the feeding regime illustrated that prolonged consumption of the western diet chow led to a large increase in the immune response activity of the brains of mice from both strains. Specifically, the diet greatly increased the activity of microglia and monocytes and within these there was a significant increase in the number expressing TREM2.
The findings of the study strengthen the body of evidence supporting the role of immune activity increases in Alzheimer’s disease, as well as indicating for the first time a link between increases in TREM2+ cells in response to a western diet.
The study also discovered an association between TREM2+ cell numbers and increased beta-amyloid plaque burden in the brains of mice. These results hint to potential benefits in the targeting of TREM2 for patients with diet-related cognitive decline.