Posts tagged aging
Articles and news from the latest research reports.
The endocannabinoid system in normal and pathological brain ageing
The role of endocannabinoids as inhibitory retrograde transmitters is now widely known and intensively studied. However, endocannabinoids also influence neuronal activity by exerting neuroprotective effects and regulating glial responses. This review centres around this less-studied area, focusing on the cellular and molecular mechanisms underlying the protective effect of the cannabinoid system in brain ageing. The progression of ageing is largely determined by the balance between detrimental, pro-ageing, largely stochastic processes, and the activity of the homeostatic defence system. Experimental evidence suggests that the cannabinoid system is part of the latter system. Cannabinoids as regulators of mitochondrial activity, as anti-oxidants and as modulators of clearance processes protect neurons on the molecular level. On the cellular level, the cannabinoid system regulates the expression of brain-derived neurotrophic factor and neurogenesis. Neuroinflammatory processes contributing to the progression of normal brain ageing and to the pathogenesis of neurodegenerative diseases are suppressed by cannabinoids, suggesting that they may also influence the ageing process on the system level. In good agreement with the hypothesized beneficial role of cannabinoid system activity against brain ageing, it was shown that animals lacking CB1 receptors show early onset of learning deficits associated with age-related histological and molecular changes. In preclinical models of neurodegenerative disorders, cannabinoids show beneficial effects, but the clinical evidence regarding their efficacy as therapeutic tools is either inconclusive or still missing.
Sport Makes Middle-Aged People Smarter
High-intensity interval training makes middle-aged people not only healthier but smarter, showed a Montreal Heart Institute (MHI) study led by Dr. Anil Nigam of the MHI and University of Montreal, in collaboration with the Montreal Geriatric University Institute.
“We worked with six adults who all followed a four-month program of twice weekly interval training on stationary bicycles and twice weekly resistance training. Cognitive function, VO2max and brain oxygenation during exercise testing revealed that the participants’ cognitive functions had greatly improved thanks to the exercise,” Dr. Nigam said. VO2max is the maximum capacity of an individual’s body to transport and use oxygen during exercise. It impacts on the body’s ability to oxygenate the brain and is related to cognitive function.
“Our participants underwent a battery of cognitive, biological and physiological tests before the program began in order to determine their cognitive functions, body composition, cardiovascular risk, brain oxygenation during exercise and maximal aerobic capacity,” Dr. Nigam explained.
“After the program was finished, we discovered that their waist circumference and particularly their trunk fat mass had decreased. We also found that their VO2max, insulin sensitivity had increased significantly, in tandem with their score on the cognitive tests and the oxygenation signals in the brain during exercise,” Dr Nigam said. Insulin sensitivity is the ability of sugar to enter body tissue (mainly liver and muscle.)
Robots in the Home: Will Older Adults Roll Out the Welcome Mat?
Robots have the potential to help older adults with daily activities that can become more challenging with age. But are people willing to use and accept the new technology? A study by the Georgia Institute of Technology indicates the answer is yes, unless the tasks involve personal care or social activities.
After showing adults (ages 65 to 93 years) a video of a robot’s capabilities, researchers interviewed them about their willingness for assistance with 48 common household tasks. Participants generally preferred robotic help over human help for chores such as cleaning the kitchen, doing laundry and taking out the trash. But when it came to help getting dressed, eating and bathing, the adults tended to say they would prefer human assistance over robot assistance. They also preferred human help for social activities, such as calling family and friends or entertaining guests.
Georgia Tech’s Cory-Ann Smarr will present the results this week at the Human Factors Ergonomics Society Annual Meeting in Boston.
“There are many misconceptions about older adults having negative attitudes toward robots,” said Smarr, a School of Psychology graduate teaching assistant. “The people we interviewed were very enthusiastic and optimistic about robots in their daily lives. They were also very particular in their preferences, something that can assist researchers as they determine what to design and introduce in the home.”
Research group finds blood transfusions from young mice to old improves brain function
A research team from Stanford University has found that injecting the blood of young mice into older mice can cause new neural development and improved memory. Team lead Saul Villeda presented the groups’ findings at this year’s Society for Neuroscience conference.
The researchers were following up on work by another team also led by Villeda that last year found that when younger mice were given transfusions of blood from older mice, their mental faculties aged more quickly than non transfused young mice. In their paper published in the journal Nature, the team also noted that the reverse appeared to be true as well, namely that the older mice derived a degree of mental benefit from the transfusions.
In this new research, the team connected the bloodstreams of an older mouse and a younger mouse, allowing their blood to comingle. Subsequent brain scans found that the number of neural stem cells in the brains of the older mice increased by 20 percent after just a few days, indicating that new neural connections were being made – a necessary occurrence for increased memory retention.
To find out if such differences could be measured in a behavioral sense, the team gave transfusions of blood plasma from young mice to older mice and then tested them in a standard water maze; one that requires strong memory skills. The team found that the transfused mice were able to perform as well as much younger mice, while a similar group of older mice that did not get transfusions were much less successful at solving the maze.
Villeda pointed out in his talk that his team’s findings don’t indicate that older people should try to obtain transfusions from younger people to stave off dementia or Alzheimer’s disease, as it’s not yet known if the same results might be had. What needs to happen, he said, is for researchers to look more closely at young mouse blood compared to the blood of older mice to discover what differences in it might account for the increased neural buildup it offers to older mice.
(Source: medicalxpress.com)
Link Between Smoking And Cataracts Discovered
Cigarettes have already been linked to a plethora of different diseases and adverse health conditions, and now a new study has found that the smoking could also increase the risk of developing cataracts in some individuals.
Dr. Juan Ye of the Zhejiang University Institute of Ophthalmology and colleagues conducted a meta-analysis, reviewing a dozen cohorts and eight case-control studies from five continents (Africa, Asia, Australia, Europe and North America) to determine smoking’s impact on the development of age-related cataracts, the leading cause of vision loss and blindness in the world.
They looked at the occurrence of age-related cataract in individuals who had smoked cigarettes versus those who had never lit up. They also looked at the differences between former and current smokers, as well as each of the three different types of cataract that can develop in older individuals, the Association for Research and Vision in Ophthalmology (ARVO) explained in an October 12 press release.
“The results showed that every individual that ever smoked cigarettes was associated with an increased risk of age-related cataract, with a higher risk of incidence in current smokers,” they said, adding that “former and current smokers showed a positive association with two of the subtypes: nuclear cataract, when the clouding is in the central nucleus of the eye, and subscapular cataract, when the clouding is in the rear of the lens capsule.”
The study did not find a link between smoking and cortical cataract, a type of cataract in which the cortex of the lens is affected by cloudiness. Their findings have been published in the journal Investigative Ophthalmology & Visual Science (IOVS).
“Although cataracts can be removed surgically to restore sight, many people remain blind from cataracts due to inadequate surgical services and high surgery expenses,” Ye said. “Identifying modifiable risk factors for cataracts may help establish preventive measures and reduce the financial as well as clinical burden caused by the disease.”
“We think our analysis may inspire more high-quality epidemiological studies” the study author added. “Our analysis shows that association between smoking and the risk of age-related cataract differ by subtypes, suggesting that pathophysiologic processes may differ in the different cataract types.”
(Source: redorbit.com)
Chewing Ability Linked to Reduced Dementia Risk
The population is aging, and the older we become the more likely it is that we risk deterioration of our cognitive functions, such as memory, decision-making and problem solving. Research indicates several possible contributors to these changes, with several studies demonstrating an association between not having teeth and loss of cognitive function and a higher risk of dementia.
One reason for this could be that few or no teeth makes chewing difficult, which leads to a reduction in the blood flow to the brain. However, to date there has been no direct investigation into the significance of chewing ability in a national representative sample of elderly people.
Now a team comprised of researchers from the Department of Dental Medicine and the Aging Research Center (ARC) at Karolinska Institutet and from Karlstad University in Sweden have looked at tooth loss, chewing ability and cognitive function in a random nationwide sample of 557 people aged 77 or older. They found that those who had difficulty chewing hard food such as apples had a significantly higher risk of developing cognitive impairments. This correlation remained even when controlling for sex, age, education and mental health problems, variables that are often reported to impact on cognition. Whether chewing ability was sustained with natural teeth or dentures also had no bearing on the effect.
The results are published in the Journal of the American Geriatrics Society (JAGS).
Omega-3 Supplements May Slow A Biological Effect of Aging
Taking enough omega-3 fatty acid supplements to change the balance of oils in the diet could slow a key biological process linked to aging, new research suggests.
The study showed that most overweight but healthy middle-aged and older adults who took omega-3 supplements for four months altered a ratio of their fatty acid consumption in a way that helped preserve tiny segments of DNA in their white blood cells.
These segments, called telomeres, are known to shorten over time in many types of cells as a consequence of aging. In the study, lengthening of telomeres in immune system cells was more prevalent in people who substantially improved the ratio of omega-3s to other fatty acids in their diet.
Omega-3 supplementation also reduced oxidative stress, caused by excessive free radicals in the blood, by about 15 percent compared to effects seen in the placebo group.
“The telomere finding is provocative in that it suggests the possibility that a nutritional supplement might actually make a difference in aging,” said Jan Kiecolt-Glaser, professor of psychiatry and psychology at Ohio State and lead author of the study.
Scientists discover how the brain ages
Researchers at Newcastle University have revealed the mechanism by which neurons, the nerve cells in the brain and other parts of the body, age.
The research, published in Aging Cell, opens up new avenues of understanding for conditions where the ageing of neurons are known to be responsible, such as dementia and Parkinson’s disease.
The ageing process has its roots deep within the cells and molecules that make up our bodies. Experts have previously identified the molecular pathway that react to cell damage and stems the cell’s ability to divide, known as cell senescence.
However, in cells that do not have this ability to divide, such as neurons in the brain and elsewhere, little was understood of the ageing process. Now a team of scientists at Newcastle University, led by Professor Thomas von Zglinicki have shown that these cells follow the same pathway.
This challenges previous assumptions on cell senescence and opens new areas to explore in terms of treatments for conditions such as dementia, motor neuron disease or age-related hearing loss.
Newcastle University’s Professor Thomas von Zglinicki who led the research said: “We want to continue our work looking at the pathways in human brains as this study provides us with a new concept as to how damage can spread from the first affected area to the whole brain.”
Working with the University’s special colony of aged mice, the scientists have discovered that ageing in neurons follows exactly the same rules as in senescing fibroblasts, the cells which divide in the skin to repair wounds.
DNA damage responses essentially re-program senescent fibroblasts to produce and secrete a host of dangerous substances including oxygen free radicals or reactive oxygen species (ROS) and pro-inflammatory signalling molecules. This makes senescent cells the ‘rotten apple in a basket’ that can damage and spoil the intact cells in their neighbourhood. However, so far it was always thought that ageing in cells that can’t divide - post-mitotic, non-proliferating cells - like neurons would follow a completely different pathway.
Now, this research explains that in fact ageing in neurons follows exactly the same rules as in senescing fibroblasts.
Professor von Zglinicki, professor of Cellular Gerontology at Newcastle University said: “We will now need to find out whether the same mechanisms we detected in mouse brains are also associated with brain ageing and cognitive loss in humans. We might have opened up a short-cut towards understanding brain ageing, should that be the case.”
Dr Diana Jurk, who did most of this work during her PhD in the von Zglinicki group, said: “It was absolutely fascinating to see how ageing processes that we always thought of as completely separate turned out to be identical. Suddenly so much disparate knowledge came together and made sense.”
(Source: ncl.ac.uk)
Even in normal range, high blood sugar linked to brain shrinkage
September 3, 2012
People whose blood sugar is on the high end of the normal range may be at greater risk of brain shrinkage that occurs with aging and diseases such as dementia, according to new research published in the September 4, 2012, print issue of Neurology, the medical journal of the American Academy of Neurology.
"Numerous studies have shown a link between type 2 diabetes and brain shrinkage and dementia, but we haven’t known much about whether people with blood sugar on the high end of normal experience these same effects," said study author Nicolas Cherbuin, PhD, with Australian National University in Canberra.
The study involved 249 people age 60 to 64 who had blood sugar in the normal range as defined by the World Health Organization. The participants had brain scans at the start of the study and again an average of four years later.
Those with higher fasting blood sugar levels within the normal range and below 6.1 mmol/l (or 110 mg/dL) were more likely to have a loss of brain volume in the areas of the hippocampus and the amygdala, areas that are involved in memory and cognitive skills, than those with lower blood sugar levels. A fasting blood sugar level of 10.0 mmol/l (180 mg/dL) or higher was defined as diabetes and a level of 6.1 mmol/l (110 mg/dL) was considered impaired, or prediabetes.
After controlling for age, high blood pressure, smoking, alcohol use and other factors, the researchers found that blood sugar on the high end of normal accounted for six to 10 percent of the brain shrinkage.
"These findings suggest that even for people who do not have diabetes, blood sugar levels could have an impact on brain health," Cherbuin said. "More research is needed, but these findings may lead us to re-evaluate the concept of normal blood sugar levels and the definition of diabetes."
Source: medicalxpress.com
For 25 years, the rhesus monkeys were kept semi-starved, lean and hungry. The males’ weights were so low they were the equivalent of a 6-foot-tall man who tipped the scales at just 120 to 133 pounds. The hope was that if the monkeys lived longer, healthier lives by eating a lot less, then maybe people, their evolutionary cousins, would, too. Some scientists, anticipating such benefits, began severely restricting their own diets.
The results of this major, long-awaited study, which began in 1987, are finally in. But it did not bring the vindication calorie restriction enthusiasts had anticipated. It turns out the skinny monkeys did not live any longer than those kept at more normal weights. Some lab test results improved, but only in monkeys put on the when they were old. The causes of death — , heart disease — were the same in both the underfed and the normally fed monkeys.