Promise of drug therapy for age-related memory loss

I’ve reported before on the evidence suggesting that carriers of the ‘Alzheimer’s gene’, APOE4, tend to have smaller brain volumes and perform worse on cognitive tests, despite being cognitively ‘normal’. However, the research hasn’t been consistent, and now a new study suggests the reason.

A number of studies have come out in recent years linking age-related cognitive decline and dementia risk to inflammation and infection (put inflammation into the “Search this site” box at the top of the page and you’ll see what I mean). New research suggests one important mechanism.

I have reported previously on research suggesting that rapamycin, a bacterial product first isolated from soil on Easter Island and used to help transplant patients prevent organ rejection, might improve learning and memory. Following on from this research, a new mouse study has extended these findings by adding rapamycin to the diet of healthy mice throughout their life span. Excitingly, it found that cognition was improved in young mice, and abolished normal cognitive decline in older mice.

A new study, involving 1,219 dementia-free older adults (65+), has found that the more omega-3 fatty acids the person consumed, the lower the level of beta-amyloid in the blood (a proxy for brain levels). Consuming a gram of omega-3 more than the average per day was associated with 20-30% lower beta-amyloid levels. A gram of omega-3 equates to around half a fillet of salmon per week.

I’ve mentioned before that, for some few people, exercise doesn’t seem to have a benefit, and the benefits of exercise for fighting age-related cognitive decline may not apply to those carrying the Alzheimer’s gene.

The study involved 4,134 people (average age 59) who worked at the French national gas and electric company, of whom most worked at the company for their entire career. Their lifetime exposure to chlorinated solvents, petroleum solvents, benzene and non-benzene aromatic solvents was estimated, and they were given the Digit Symbol Substitution Test to assess cognitive performance. Cognitive impairment was defined as scoring below the 25th percentile. Most of the participants (88%) were retired.

More findings from the long-running Mayo Clinic Study of Aging reveal that using a computer plus taking moderate exercise reduces your risk of mild cognitive impairment significantly more than you would expect from simply adding together these two beneficial activities.

Over the years, I have reported on several studies that have found evidence that colorful berries — blueberries in particular (but I think that’s more of an artifact, due to the relative cheapness of these berries in North America) — benefit older brains. Indeed, I myself consume these every day (in my lunch smoothie) for this very reason (of course, the fact that they taste so good doesn’t hurt!).

Older adults who sleep poorly react to stress with increased inflammation

A study involving 83 older adults (average age 61) has found that poor sleepers reacted to a stressful situation with a significantly greater inflammatory response than good sleepers. High levels of inflammation increase the risk of several disorders, including cardiovascular disease and diabetes, and have been implicated in Alzheimer’s.

A number of studies, principally involving rodents, have established that physical exercise stimulates the creation of new brain cells in the hippocampus. A recent study attempted to uncover more about the mechanism.

Using two drugs that work directly on muscles, producing the physical effects of exercise, the researchers compared the effects on the brain. One drug (Aicar) improves the fitness of even sedentary animals. The other drug increases the effects of exercise on animals that exercise, but has little effect on sedentary animals.