A few months ago, I reported on an exciting finding that rapamycin, a drug currently used in transplant patients, improved memory in Alzheimer's mice. Now a different strain of mice (ones engineered to have defects in the genes that make amyloid precursor protein) has also shown improvements in learning and memory, correlated with less damage in brain tissue, after rapamycin treatment lowered levels of amyloid-beta-42. The mice given the drug performed at levels comparable with normal mice.
Latest Research News
Great news for those who crave the benefits of meditation but find the thought a bit intimidating! While a number of studies have demonstrated that long-term mindfulness meditation practice promotes executive functioning and the ability to sustain attention, now a small study involving 49 students has found that as little as four sessions of 20 minutes produced a significant improvement in critical cognitive skills, compared to those who spent an equal amount of time listening to Tolkien's The Hobbit being read aloud.
A variant of a gene called the fat mass and obesity associated (FTO) gene causes people to gain weight and puts them at risk for obesity. The gene variant is found in nearly half of all people in the U.S. with European ancestry, around one-quarter of U.S. Hispanics, 15 percent of African Americans and 15 percent of Asian Americans. A new study involving 206 healthy elderly subjects from around the U.S. now suggests that this gene variant is also associated with loss of brain tissue. It’s not clear why, but the gene is highly expressed in the brain.
While everyone agrees that amyloid-beta protein is part of the problem, not everyone agrees that amyloid plaques are the cause (or one of them) of Alzheimer’s. Other forms of amyloid-beta have been pointed to, including floating clumps called oligomers or ADDLs. A new study, using mice engineered to form only these oligomers, and never any plaques, throughout their lives, provides more support for this theory.
A five-year study involving 214 children born to healthy, non-smoking Caucasian women in Krakow, Poland, has found that those prenatally exposed to high levels of polycyclic aromatic hydrocarbons (PAHs) had a significant reduction in scores on a standardized test of reasoning ability and intelligence at age 5 (an estimated average decrease of 3.8 IQ points). The mothers wore small backpack personal air monitors for 48 hours during pregnancy to estimate their babies' PAH exposure.
The role of the catechol-O-methyltransferase (COMT) gene in cognitive function has been the subject of some debate. The gene, which affects dopamine, comes in two flavors: Val and Met. One recent study found no difference between healthy carriers of these two gene variants in terms of cognitive performance, but did find differences in terms of neural activity. Another found that, although the gene did not affect Alzheimer’s risk in its own, it acted synergistically with the Alzheimer’s gene variant to do so.
A study involving 236 persons with multiple sclerosis has found that only 7% of those with secondary-progressive MS showed sufficient vitamin D in their blood, compared to 18.3% of patients with the less severe relapsing-remitting type, and that higher levels of vitamin D3 and its byproducts were associated with better scores on cognitive tests (especially reasoning and planning), and less brain atrophy and fewer brain lesions. Lower-than-normal vitamin D status is known to be associated with a higher risk of developing MS
Previous research has found that unexplained weight loss is an early sign of Alzheimer's. Now a study involving 140 older adults (60+), of whom half had early-stage Alzheimer's disease, has revealed that it is not the overall weight or fat levels that are important, but the loss of lean mass (weight of an individual's bones, muscles and organs without body fat). This directly correlated with reductions in the volume of the whole brain and of white matter only, along with declines in cognitive performance.
A study involving five patients with severe amnesia due to damage in the hippocampus, resulting in a condition comparable to Alzheimer's, has found that memory tests given 5-10 minutes after sad and happy film clips showed little (if any) memory of the details, but the generated emotion lasted for 20 to 30 minutes afterward. Interestingly, normal controls also felt happy for about the same length of time, but the impact of sad scenes was shorter. The findings challenge the idea that by minimizing a specific memory of past trauma, associated sadness will also decrease.
The largest ever trial of fish oil supplements has found no evidence that they offer benefits for cognitive function in older people. The British study enrolled 867 participants aged 70-80 years, and lasted two years. After two years, those receiving fish oil capsules had significantly higher levels of omega-3 fatty acids in their blood than those receiving placebo capsules. However, cognitive function did not decline in either group over the period. The researchers caution that it may be that more time is needed for benefits to show.