One cause of damage in older brains, and how exercise can help

September, 2011

Two mice studies indicate that an increase in a protein involved in immune response may be behind the reduced ability of older brains to create new neurons, and that exercise produces a protein that helps protect against damage caused by illness, injury, surgery and pollutants.

In the first mouse study, when young and old mice were conjoined, allowing blood to flow between the two, the young mice showed a decrease in neurogenesis while the old mice showed an increase. When blood plasma was then taken from old mice and injected into young mice, there was a similar decrease in neurogenesis, and impairments in memory and learning.

Analysis of the concentrations of blood proteins in the conjoined animals revealed the chemokine (a type of cytokine) whose level in the blood showed the biggest change — CCL11, or eotaxin. When this was injected into young mice, they indeed showed a decrease in neurogenesis, and this was reversed once an antibody for the chemokine was injected. Blood levels of CCL11 were found to increase with age in both mice and humans.

The chemokine was a surprise, because to date the only known role of CCL11 is that of attracting immune cells involved in allergy and asthma. It is thought that most likely it doesn’t have a direct effect on neurogenesis, but has its effect through, perhaps, triggering immune cells to produce inflammation.

Exercise is known to at least partially reverse loss of neurogenesis. Exercise has also been shown to produce chemicals that prevent inflammation. Following research showing that exercise after brain injury can help the brain repair itself, another mouse study has found that mice who exercised regularly produced interleukin-6 (a cytokine involved in immune response) in the hippocampus. When the mice were then exposed to a chemical that destroys the hippocampus, the interleukin-6 dampened the harmful inflammatory response, and prevented the loss of function that is usually observed.

One of the actions of interleukin-6 that brings about a reduction in inflammation is to inhibit tumor necrosis factor. Interestingly, I previously reported on a finding that inhibiting tumor necrosis factor in mice decreased cognitive decline that often follows surgery.

This suggests not only that exercise helps protect the brain from the damage caused by inflammation, but also that it might help protect against other damage, such as that caused by environmental toxins, injury, or post-surgical cognitive decline. The curry spice cucurmin, and green tea, are also thought to inhibit tumor necrosis factor.

Reference: 

Related News

In the past few months, several studies have come out showing the value of three different tests of people's sense of smell for improving the accuracy of

A study comparing the language abilities of 22 healthy young individuals, 24 healthy older individuals and 22 people with

Following on from a previous study showing that such a virtual supermarket game administered by a trained professional can detect

Data from the Women's Health Initiative Memory Study, involving 6,467 postmenopausal women (65+) who reported some level of caffeine consumption, has found that those who consumed above average amounts of coffee had a lower risk of developing dementia.

Our bodies’ ability to regulate its temperature gets worse with age, along with a slowing metabolism. We also become more vulnerable to Alzheimer's as we age. A study compared mice genetically engineered to manifest Alzheimer's symptoms as they age with normal mice.

People with Alzheimer's disease develop problems in recognizing familiar faces. It has been thought that this is just part of their general impairment, but a new study indicates that a specific, face-related impairment develops early in the disease.

Data from 876 patients (average age 78) in the 30-year Cardiovascular Health Study show that virtually any type of aerobic physical activity can improve brain volume and reduce Alzheimer's risk.

A study involving 100 older adults (aged 80-99) with hearing loss has found that those who used a hearing aid performed significantly better on a cognitive test (MMSE) than those who didn't use a hearing aid, despite having poorer hearing.

A study involving 65 older adults (average age 66), of whom 35 had type 2 diabetes, has found that after two years, those with diabetes had decreases in their ability to regulate blood flow in the brain, and a reduced ability to regulate blood flow was associated with lower cognitive scores.

A small study that fitted 29 young adults (18-31) and 31 older adults (55-82) with a device that recorded steps taken and the vigor and speed with which they were made, has found that those older adults with a higher step rate performed better on memory tasks than those who were more sedentary.

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news
Error | About memory

Error

The website encountered an unexpected error. Please try again later.