Posts Tagged ‘ageing’

By Ashley P. Taylor

During adulthood, the mouse brain manufactures new neurons in several locations, including the hippocampus and the subventricular zone of the forebrain. The hypothalamus, previously identified as an area with an important role in aging, also generates new neurons from neural stem cells. In a study published July 26 in Nature, Dongsheng Cai and his team at the Albert Einstein College of Medicine in New York connect the dots between these two observations, reporting that hypothalamic neural stem cells have widespread effects on the rate of aging in mice.

In what David Sinclair, who studies aging at Harvard Medical School and who was not involved in the work, calls a “Herculean effort,” the researchers “discovered that stem cells in the hypothalamus of the mouse play a role in overall health and life span,” he tells The Scientist.

Cai and his team found that killing hypothalamic neural stem cells accelerates aging, and transplantation of additional neural stem cells into the same brain region slows it down. Further, the stem cells’ anti-aging effects could be reproduced simply by administering the cells’ secreted vesicles, called exosomes, containing microRNAs (miRNAs).

“If this is true for humans, one could imagine a day when we are treated with these small RNAs injected into our bodies or even implanted with new hypothalamic stem cells to keep us younger for longer,” Sinclair adds.

Researchers who study aging have long been searching for a central location that controls the process system-wide. In a 2013 paper, Cai and his team reported aging-associated inflammation in the hypothalamus of the mouse, which they could experimentally manipulate to speed up or slow down various types of aging-related decline, from muscle endurance to cognitive skills.

This study, Cai says, suggested the hypothalamus might be that central locus in control of aging. The researchers wanted to understand more about how this region of the brain drives aging and what role hypothalamic neural stem cells might play in that process, so they undertook a series of experiments.

Age-defying stem cells

The researchers first confirmed that cells bearing protein markers of neural stem cells (Sox2 and Bmi1) were present in the hypothalamus of early-to-middle-aged mice (11 to 16 months old) and that the number of those cells decreased in older mice.

Next, they destroyed neuronal stem cells in the hypothalamus by injecting the third ventricle, adjacent to the hypothalamic region where the stem cells are found, with a lentivirus that converted an administered compound into a toxin in cells expressing the stem-cell marker Sox2. Three or four months later, the researchers compared a variety of aging-related measures, including muscle endurance, coordination, social behaviors, novel object recognition, and cognitive performance, between mice injected with the virus and various control groups of mice that received a brain injection of some sort but in which the toxin could not be produced and the hypothalamic stem cells were consequently not ablated.

The mice in the experimental group lost 70 percent of their hypothalamic stem cells and, based on results of the physiological tests, had accelerated aging. Mice with ablated hypothalamic stem cells also died earlier than control mice.

Next, the researchers implanted middle-aged mice with neural stem cells derived from newborn mice to see if the additional stem cells would slow aging. But the implanted stem cells almost all died, which the researchers believe was a result of the inflammatory environment of the aging hypothalamus. Newborn neuronal stem cells genetically engineered to withstand that environment, on the other hand, did survive, and mice implanted with those cells lived longer and performed better on aging-related measures than control mice.

“What’s cool about this study is that they specifically delete a population of cells in the hypothalamus of the brain . . . and they show pretty striking alterations in whole-body aging,” says Anna Molofsky, a psychiatrist at the University of California, San Francisco, who studies glial cells and whose graduate work focused on neuronal stem cells and aging. “That’s really showing that there’s a mechanism within the brain that’s regulating whole-body organismal aging,” she adds. Molofsky, who was not involved in the work, says that these results support the idea of the hypothalamus as a central regulator of aging.

Anti-aging mechanism

Although neural stem cells are known for their ability to produce new neurons, that doesn’t seem to be their primary method for protecting against aging. The anti-aging effects of these hypothalamic stem cells were visible at around four months—not long enough, the authors write, for significant adult neurogenesis to have taken place.

The authors looked instead for some other factor that might be responsible for the stem cells’ effects. In the hypothalamic neural stem cells, the researchers detected exosomes—secreted vesicles that can contain RNA and proteins—containing a variety of miRNAs, short RNA molecules that inhibit the expression of targeted genes. These exosomes were not present in non-stem cells of the hypothalamus.

To test the effects of the exosomes alone on aging, the researchers purified the vesicles from cultured hypothalamic neural stem cells and transplanted them into middle-aged mice, finding that the exosome-treated mice aged more slowly than vehicle-treated controls. They also found that the exosomes could ameliorate the aging symptoms of mice whose hypothalamic neurons had been ablated.

Cai says microRNAs could be a potential mechanism by which hypothalamic neural stem cells have such wide-ranging effects on aging, yet he believes that neurogenesis may also be involved.

Regardless of the mechanism, Molofsky says, “the medical applications could be pretty profound.” The phenotypes, such as muscle mass and skin thickness, affected by these stem cells are the same ones that cause age-related disease, she notes. “The fact that you can reverse that with a brain-specific modulation, potentially, in a cell type that one could pharmacologically target, I think potentially that could be very profound, assuming that the mouse work translates to humans.”

Y. Zhang et al., “Hypothalamic stem cells control ageing speed partly through exosomal miRNAs,” Nature, doi:10.1038/nature23282, 2017.

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Every hour you run extends your life span by seven hours, a new study has revealed.

Scientists say that running just one hour a week is the most effective exercise to increase life expectancy.

This holds true no matter how many miles or how fast you run, the researchers claim.
For those that take this advice to heart and run regularly, they say you can extend your life span by up to three years.

The study, conducted at Iowa State University, reanalyzed data from The Cooper Institute, in Texas, and also examined results from a number of other recent studies that looked at the link between exercise and mortality.

Scientists found that the new review reinforced the findings of earlier research.
At whatever pace or mileage, a person’s risk of premature death dropped by 40 percent when he or she took up running.

This applied even when researchers controlled for smoking, drinking or a history of health problems such as obesity.

Three years ago, the same team conducted a study that analyzed more than 55,000 adults, and determined that running for just seven minutes a day could help slash the risk of dying from heart disease.

They followed participants over a period of 15 years, and found that of the more than 3,000 who died, only one-third of deaths were from heart disease.

Co-author Dr Duck-chul High-mileage runners also questioned if they were overperforming and if, at some point, running would actually contribute to premature mortality.
After analyzing the data in the new study, scientists determined that hour for hour, running statistically returns more time to people’s lives than it consumes.
In The Cooper Institute study, participants reported an average of two hours running per week.
The amount ran over the course of 40 years would add up to fewer than six months, but it could increase life expectancy by more than three years.

The researchers also determined that if every non-runner who had been part of the reviewed studies took up the sport, there would have been 16 percent fewer deaths over all, and 25 percent fewer fatal heart attacks.

Other types of exercise were also found to be beneficial. Walking and cycling dropped the risk of premature death by about 12 percent.

Dr Lee says scientists remain uncertain as to why running helps with longevity.

But he says it’s likely because the sport combats many common risk factors for early death, including high blood pressure and extra body fat, especially around the middle.

It also raises aerobic fitness, one of the best-known indicators for long-term health.
Running, however, does not make you immortal and the life expectancy rates don’t increase beyond three years.

Improvements in life expectancy generally plateaued at about four hours of running per week, Dr Lee said. But they did not decline.

Read more: http://www.dailymail.co.uk/health/article-4405252/Every-hour-run-adds-7-hours-lifespan.html#ixzz4e5eSXAzj

Look at a photo of yourself as a teenager and, mistaken fashion choices aside, it’s likely you see traces of the same person with the same personality quirks as you are today. But whether or not you truly are the same person over a lifetime—and what that notion of personhood even means—is the subject of ongoing philosophical and psychology debate.

The longest personality study of all time, published in Psychology and Aging and recently highlighted by the British Psychological Society, suggests that over the course of a lifetime, just as your physical appearance changes and your cells are constantly replaced, your personality is also transformed beyond recognition.

The study begins with data from a 1950 survey of 1,208 14-year-olds in Scotland. Teachers were asked to use six questionnaires to rate the teenagers on six personality traits: self-confidence, perseverance, stability of moods, conscientiousness, originality, and desire to learn. Together, the results from these questionnaires were amalgamated into a rating for one trait, which was defined as “dependability.” More than six decades later, researchers tracked down 635 of the participants, and 174 agreed to repeat testing.

This time, aged 77 years old, the participants rated themselves on the six personality traits, and also nominated a close friend or relative to do the same. Overall, there was not much overlap from the questionnaires taken 63 years earlier. “Correlations suggested no significant stability of any of the 6 characteristics or their underlying factor, dependability, over the 63-year interval,” wrote the researchers. “We hypothesized that we would find evidence of personality stability over an even longer period of 63 years, but our correlations did not support this hypothesis,” they later added.

The findings were a surprise to researchers because previous personality studies, over shorter periods of time, seemed to show consistency. Studies over several decades, focusing on participants from childhood to middle age, or from middle age to older age, showed stable personality traits. But the most recent study, covering the longest period, suggests that personality stability is disrupted over time. “The longer the interval between two assessments of personality, the weaker the relationship between the two tends to be,” the researchers write. “Our results suggest that, when the interval is increased to as much as 63 years, there is hardly any relationship at all.”

Perhaps those who had impulsive character flaws as a teenager would be grateful that certain personality traits might even out later in life. But it’s disconcerting to think that your entire personality is transformed.

“Personality refers to an individual’s characteristic patterns of thought, emotion, and behavior, together with the psychological mechanisms—hidden or not—behind those patterns,” note the authors, quoting psychology professor David Funder’s definition.

If your patterns of thought, emotions, and behavior so drastically alter over the decades, can you truly be considered the same person in old age as you were as a teenager? This question ties in with broader theories about the nature of the self. For example, there is growing neuroscience research that supports the ancient Buddhist belief that our notion of a stable “self” is nothing more than an illusion.

Perhaps this won’t surprise you if you’ve had the experience of running into a very old friend from school, and found a completely different person from the child you remembered. This research suggests that, as the decades go by, your own younger self could be similarly unrecognizable.

You’re a completely different person at 14 and 77, the longest-running personality study ever has found

Older people with a slow walking pace are at increased risk of cognitive decline and dementia, according to a new meta-analysis.

“In light of its characteristics of safety, cost-effectiveness, and ease to test and interpret, walking pace may be an effective indicator of the development of cognitive decline and dementia in older people,” Dr. Minghui Quan of Shanghai University of Sport in China and colleagues write in their report, published online December 6 in the Journal of Gerontology: Medical Sciences.

Past research has linked walking pace to cognitive dysfunction, but the size of the association and whether there is a dose-response relationship has not been studied systematically, the researchers state. To investigate, they reviewed 17 prospective studies of walking pace. Seven looked at cognitive decline, seven at dementia, and three studies included both outcomes.

The 10 studies of cognitive decline included nearly 10,000 participants, while the 10 studies with dementia as an outcome included more than 14,000. The slowest walkers had an 89% higher risk of cognitive decline (95% confidence interval, 1.54 – 2.31), but there was no linear relationship between walking pace and cognitive decline risk.

Dementia risk was 66% higher in individuals with the slowest walking pace versus those with the fastest pace (95% CI, 1.43 – 1.92). Three studies included data on dose-response relationship, and found a relative risk of cognitive decline of 1.13 for each decimeter/second drop in walking pace (95% CI, 1.08 – 1.18).

Walking pace may be an indicator of cognitive function for many reasons, Dr. Quan and colleagues note. For example, walking pace is associated with muscle strength, and muscle loss has been tied to inflammation, oxidative stress and other factors related to cognitive function.

Walking is not an automatic activity, they add, but “requires a seamless coordination of several neurologic systems including motor, sensory, and cerebellar activities.” Slow walking pace could also contribute to physical inactivity, they add, which in turn is associated with cognitive decline and dementia.

“Since a randomized clinical trial on walking pace and cognitive function may not be feasible due to practical considerations, future well-designed, large-scale, prospective cohort studies are needed to determine the age-, sex-, and population-specified cutoff values for walking pace, in order to enhance the effectiveness and efficiency of this early indicator of cognitive decline and dementia,” Dr. Quan and colleagues conclude.

By Jacqueline Howard

Whether you call them gray hairs or stress highlights, world-renowned animal scientist and autism advocate Temple Grandin wants you to know that dogs may get them prematurely, too — possibly when stressed, such as being left at home alone.

Premature graying in dogs may be an indicator of anxiety and impulsivity, according to a study published in this month’s edition of the journal Applied Animal Behaviour Science, in which Grandin served as a co-author.

Camille King, an animal behaviorist and owner of the Canine Education Center in Denver, noticed a few years ago that many impulsive and anxious dogs seemed to be prematurely turning gray. When King told Grandin about her observations, Grandin said she encouraged King to lead the research.

“The first thing I thought of when she told me that were the presidents, and how they age and get prematurely gray,” said Grandin, professor of animal science at Colorado State University, referring to American commanders in chief.

“The fact that presidents turn prematurely gray was one of the things that made me encourage her to do the study,” Grandin said. “Basically, (the study findings) validated what she had seen in years of doing dog behavior work.”

The study, conducted at Northern Illinois University, involved 400 dogs, 4 years old or younger, with non-white-colored hair so the researchers could adequately determine degrees of graying.

“Normally, dogs wouldn’t be gray at age 4,” Grandin said.

The study, conducted at Northern Illinois University, involved 400 dogs, 4 years old or younger, with non-white-colored hair so the researchers could adequately determine degrees of graying.

“Normally, dogs wouldn’t be gray at age 4,” Grandin said.

Next, the researchers compared the survey responses with how much gray hair appeared on the dogs’ muzzles in their photos.
Grandin helped the researchers build a scoring system to measure the degrees of grayness: A score of 0 is “no gray;” 1 is for gray on the front of the nose only; 2 is for gray hair halfway up the muzzle; and 3 is “full gray.”

It turned out that a high grayness score was significantly and positively predicted by survey responses that indicated both high anxiety and impulsivity.

“Essentially, the results indicate that for each standard deviation increase in the measured trait, either anxiety or impulsiveness, the odds of being in a higher rating category of muzzle grayness increase 40% to 65%,” said Thomas Smith, a professor at Northern Illinois University’s Department of Educational Technology, Research and Assessment, who was a co-author of the study.

Smith added that he was initially skeptical that a dog’s premature muzzle grayness might be linked to anxiety and impulsiveness.

“However, when we analyzed the data, the results actually were striking,” he said. “I was surprised.”
A similar association between stress and premature graying possibly could be found in other mammals, outside of humans and dogs, but more research is needed, Grandin said.

The new study appears to extend what has been previously seen in people — the relationship between stress and gray hair — to dogs, said Matt Kaeberlein, a professor and co-director of the University of Washington’s Dog Aging Project, who was not involved in the new study.

“There are a few things about this study that I really like. One is that it nicely illustrates another way in which dogs and humans are similar, specifically in this case, the way we interact with our environment to experience stress. I like the innovative approach of applying facial image recognition to dogs,” Kaeberlein said.

“I do think it’s important to keep in mind that while hair graying is a useful ‘biomarker’ of aging and experienced stress, it is not particularly precise. We should avoid interpreting causation from correlation,” he said about the study. “Many dogs and people get gray hair for reasons unrelated to their perception of stress or anxiety, so while anxiety (or) stress appears to cause hair graying, gray hair is not necessarily caused by anxiety or stress. In other words, just because your dog gets gray hair doesn’t mean she or he is stressed out.”

For instance, more research is needed to determine how much genetics might play a role not only in premature graying in young dogs but also how a dog might respond to stress, Grandin said. She added that additional research could also determine how much of the study results were influenced by anxiety and impulsivity, respectively.

“There’s probably some genetic influence where some dogs that are impulsive and anxious don’t turn gray. You see, that would be your genetic interaction, but when you take a big population of dogs, it statistically comes out that anxious and impulsive dogs are more likely to start turning gray before age 4,” Grandin said.

“Genetic factors are important, but genetic factors also can be modified by experience, so you can’t just say an animal’s hard-wired genetics, it’s not. It’s both. Both genetics and the environment are important,” she said.

http://www.cnn.com/2016/12/23/health/stress-dogs-gray-hair/index.html


By Lisa Rapaport

Women who have a sunny outlook on life may live longer than their peers who take a dimmer view of the world, a recent study suggests.

Researchers analyzed data collected over eight years on about 70,000 women and found that the most optimistic people were significantly less likely to die from cancer, heart disease, stroke, respiratory disease or infections during the study period than the least optimistic.

“Optimistic people tend to act in healthier ways (i.e., more exercise, healthier diets, higher quality sleep, etc.), which reduces one’s risk of death,” said one of the study’s lead authors, Kaitlin Hagan, a public health researcher at Brigham and Women’s Hospital and Harvard University in Boston.

“Optimism may also have a direct impact on our biological functioning,” Hagan added by email. “Other studies have shown that higher optimism is linked with lower inflammation, healthier lipid levels and higher antioxidants.”

Hagan and colleagues examined data from the Nurses Health Study, which began following female registered nurses in 1976 when they were 30 to 55 years old. The study surveyed women about their physical and mental health as well as their habits related to things like diet, exercise, smoking and drinking.

Starting in 2004, the survey added a question about optimism. Beginning that year, and continuing through 2012, researchers looked at what participants said about optimism to see how this related to their other responses and their survival odds.

Researchers divided women into four groups, from least to most optimistic.

Compared with the least optimistic women, those in the most optimistic group were 29 percent less likely to die of all causes during the study period, the researchers report in the American Journal of Epidemiology, December 7th.

Once they adjusted the data for health habits, greater optimism was still associated with lower odds of dying during the study, though the effect wasn’t as pronounced.

Still, the most optimistic women had 16 percent lower odds of dying from cancer during the study, 38 percent lower odds of death from heart disease or respiratory disease, 39 percent lower odds of dying from stroke and a 52 percent lower risk of death from an infection.

While other studies have linked optimism with reduced risk of early death from cardiovascular problems, this was the first to find a link between optimism and reduced risk from other major causes, the study authors note.

One limitation of the study is the possibility that in some cases, underlying health problems caused a lack of optimism, rather than a grim outlook on life making people sick, the authors point out.

They also didn’t include men, though previous research has found the connection between optimism and health is similar for both sexes, said the study’s other lead author, Dr. Eric Kim, also of Brigham and Women’s and Harvard.

Despite the lack of men in the study, the findings still suggest that it may be worthwhile to pursue public health efforts focused on optimism for all patients, Kim said by email.

That’s because even though some people may have a less positive outlook on life for reasons beyond their control like unemployment or a debilitating illness, some previous research suggests that optimism can be learned.

“Negative thinking isn’t the cause or the only contributor to these illnesses,” said Dr. Susan Albers, a psychologist at the Cleveland Clinic in Ohio who wasn’t involved in the study. “Mindset is just one factor, but the results of the study indicate they are a significant one and can’t be ignored.”

Some people can develop optimism when it doesn’t come naturally, Albers added by email.

“It is worth tweaking your mindset as much as taking your medicine,” Albers said. “Work with a counselor, join with a friend, hang up optimistic messages, watch films and movies with a hopeful, positive message, find the silver lining in the situation.”

http://www.psychcongress.com/news/optimistic-women-may-live-longer

In Australia, a University of Sydney study has linked improved cognitive function with stronger muscles using a steady regime of weightlifting exercises. Published in the Journal of American Geriatrics, the study used a system known as SMART (Study of Mental and Resistance Training). A trial was done on a group of patients age 55 to 68, suffering MCI (mild cognitive impairment). This condition is not as serious as full-blown dementia, as people affected only have mild cognitive symptoms not severe enough to disable them from normal daily life.

People who have MCI though are at high risk of developing dementia or Alzheimer’s with 80% going on to develop Alzheimer’s disease within 6 years. The World Alzheimer Report 2016 has reported that 47 million people globally are affected by dementia related diseases, with an expected three-fold increase by the year 2050. The cost of care is high for these patients, with a focus only on extending the quality of life for those living with dementia.

Weight Training Improves Cognitive Functions

The aim of the study was to measure the effects of different physical and mental activities on the human brain. Researchers examined 100 people affected by MCI. They were divided into four groups, and assigned the activities as seen below:
•weightlifting exercises
•seated stretching exercises
•real cognitive training on a computer
•placebo training on a computer

The weightlifting trial lasted for 6 months with exercising done twice a week. As the participants got stronger, they increased the amount of weight for each exercise. The exercises were done while trying to maintain 80% or greater at their peak strength.

Surprisingly, only the weight training activity demonstrated a measured improvement in brain function. The stretching exercises, cognitive training, and placebo training did not yield any results. This proved a link between muscle strength gained through physical training and the improved cognitive functions. According to Doctor Yorgi Mavros, lead author of the study, there was a clear relationship between mental functions and increased muscular strength. And the stronger the muscles got the greater the mental improvement.

In an earlier study, researchers scanned the brains of older adults after 6 months of weight training. The results mirrored the SMART trial with measured brain growth. Although previous studies have been done that show links between exercise and improved brain functions, the SMART system went into detail on the types of exercise required to get the best results. This study was a first in showing evidence of a link between strength training and improved cognitive functions for people with MCI who were 55 or older.

Delaying or Stopping Aging in the Brain

People increase their chances of brain impairment by not exercising. Exercise can help prevent dementia and Alzheimer’s disease, but also improves cardiovascular health and some other cognitive processes like multitasking.

Doctor Mavros is a strong advocate for encouraging resistance exercises as people start to grow older. The result could be a much healthier aging population. Mavros stressed the need for exercising at least 2-3 time per week at a high enough intensity in order to get the maximum cognitive benefits.

Professor Maria Fiatarone Singh of the University of Sydney wants to discover the underlying process of muscle growth and brain growth and its effect on cognitive performance. The next step is deciding how to prescribe optimal exercise programs to individuals with mild cognitive impairment, and to those who want to prevent MCI.

The authors of the study pointed out that the mechanism behind weight training and improving cognitive impairment has not yet been determined and future study may uncover the secret of delaying or even stopping degenerative aging effects of the brain.

http://www.worldhealth.net/news/stronger-muscles-improved-cognitive-function/