Alzheimer's Risk Gene and Heavy Metal Exposure May Impair Cognition

A mice study in Toxicological Sciences suggests people who already have a copy of the E4 variant of the human apolipoprotein E (APOE4) gene, which places them at risk of Alzheimer's, may suffer cognitive decline as a result of exposure to the heavy metal cadmium, reports Medical News Today . Researchers used mouse models of Alzheimer's with an activated version of the E4 or E3 APOE variant, then added low doses of cadmium to the drinking water, which the mice consumed for 14 weeks. The mice that had ingested cadmium exhibited poorer performance in novel object location tests, signaling reduced short-term spatial working memory. These symptoms manifested earlier in mice with the APOE4 gene than those with APOE3. Onset of symptoms occurred earlier in male mice than in female mice, and mice carrying the APOE4 gene performed worse in a maze test later in life than those with APOE3. "Our study provides direct evidence for an interaction between this Alzheimer's genetic risk gene and environmental exposures on accelerated cognitive impairment," concluded University of Washington School of Public Health Professor Zhengui Xia.