Scientists said Sunday they may have unravelled how chronic stress leads to heart attack and stroke: triggering overproduction of disease-fighting white blood cells which can be harmful in excess.
Surplus cells clump together on the inner walls of arteries, restricting blood flow and encouraging the formation of clots that block circulation or break off and travel to another part of the body.
White blood cells “are important to fight infection and healing, but if you have too many of them, or they are in the wrong place, they can be harmful,” said study co-author Matthias Nahrendorf of the Harvard Medical School in Boston.
Doctors have long known that chronic stress leads to cardiovascular disease, but have not understood the mechanism.
To find the link, Nahrendorf and a team studied 29 medical residents working in an intensive care unit.
Their work environment is considered a model for chronic stress exposure given the fast pace and heavy responsibility they carry for life-and-death decisions.
Comparing blood samples taken during work hours and off duty, as well as the results of stress perception questionnaires, the researchers found a link between stress and the immune system.
Particularly, they noticed stress activate bone marrow stem cells, which in turn triggered overproduction of white blood cells, also called leukocytes.
White blood cells, crucial in wound healing and fighting off infection, can turn against their host, with devastating consequences for people with diseases like atherosclerosis — a thickening of artery walls caused by a plaque buildup.
The study then moved on to mice, which were exposed to the rodent equivalent of stress through techniques like crowding and cage tilting.
The team chose atherosclerosis-prone mice.
They found that excess white blood cells produced as a result of stress accumulated on the inside of arteries and boosted plaque growth.
“Here, they (the cells) release enzymes that soften the connective tissue and lead to disruption of the plaque,” said Nahrendorf.
“This is the typical cause of myocardial infarction (heart attack) and stroke.”
He added leukocytes were only a part of the picture — factors like high cholesterol and blood pressure, smoking and genetic traits also contribute to heart attack and stroke risk.
“Stress might push these over the brink,” the researcher told AFP. – AFP Relaxnews
The hormone known for creating soothing sensations during pleasant social and physical interactions might one day be used to maintain and repair aging muscles, according to a study conducted at the University of California at Berkeley.
Researchers say oxytocin, which is released during breastfeeding, sex, and even a warm hug, could become a viable treatment for age-related muscle wasting or sarcopenia.
Associated with social and romantic attachements, oxytocin increases libido and is thought to create social, familial and romantic bonds.
“This is the hormone that makes your heart melt when you see kittens, puppies and human babies,” said principal investigator Irina Conboy, associate professor of bioengineering and a member of the Berkeley Stem Cell Center and of the California Institute for Quantitative Biosciences (QB3). “There is an ongoing joke among my research team that we’re all happy, friendly and trusting because oxytocin permeates the lab.”
In the study, which was published in the journal Nature Communications, researchers observed oxytocin levels in mice and found them to decline with age.
Older mice were observed to have fewer oxytocin receptors in muscle stem cells.
Upon being injected with the hormone, the injured muscles of the older mice began to repair themselves after just nine days.
“The action of oxytocin was fast,” said Christian Elabd, a senior scientist in Conboy’s lab and study co-author. “The repair of muscle in the old mice was at about 80 percent of what we saw in the young mice.”
Of notable interest is that young mice that received oxytocin injections did not undergo muscular change, according to senior scientist and lead study co-author Wendy Cousin.
“This is good because it demonstrates that extra oxytocin boosts aged tissue stem cells without making muscle stem cells divide uncontrollably,” Cousin added.
Cousin envisions that oxytocin — already the key ingredient in the drug Picotin, administered to induce labor — will overtake traditional hormone replacement therapy as the go-to anti-aging treatment for women and men. Hormone replacement therapy is associated with numerous health risks and has proven ineffective in muscle regeneration.
An article by Tara Parker-Pope
From tribesmen to billionaire philanthropists, the social value of generosity is already well known. But new research suggests it also matters much more intimately than we imagined, even down to our most personal relationships.
Researchers from the University of Virginia’s National Marriage Project recently studied the role of generosity in the marriages of 2,870 men and women. Generosity was defined as “the virtue of giving good things to one’s spouse freely and abundantly” — like simply making them coffee in the morning — and researchers quizzed men and women on how often they behaved generously toward their partners. How often did they express affection? How willing were they to forgive?
The responses went right to the core of their unions. Men and women with the highest scores on the generosity scale were far more likely to report that they were “very happy” in their marriages. The benefits of generosity were particularly pronounced among couples with children. Among the parents who posted above-average scores for marital generosity, about 50 percent reported being “very happy” together. Among those with lower generosity scores, only about 14 percent claimed to be “very happy,” according to the latest “State of Our Unions” report from the National Marriage Project.
While sexual intimacy, commitment and communication are important, the focus on generosity adds a new dimension to our understanding of marital success. Though this conclusion may seem fairly self-evident, it’s not always easy to be generous to a romantic partner. The noted marriage researcher John Gottman has found that successful couples say or do at least five positive things for each negative interaction with their partner — not an easy feat.
“In marriage we are expected to do our fair share when it comes to housework, child care and being faithful, but generosity is going above and beyond the ordinary expectations with small acts of service and making an extra effort to be affectionate,” explains the University of Virginia’s W. Bradford Wilcox, who led the research. “Living that spirit of generosity in a marriage does foster a virtuous cycle that leads to both spouses on average being happier in the marriage.”
Social scientists are now wondering if this virtuous cycle extends to children too. In a study of 3-year-old twins, Israeli researchers have identified a genetic predisposition toward generosity that may be further influenced by a parent’s behavior. Preliminary findings suggest that children with more-engaged parents are more likely to be generous toward others, which may bode well for their future relationships — and their parents’ too.
“We see meaningful differences in parents’ behaviors,” said Ariel Knafo, the principal investigator and a psychologist at Hebrew University in Jerusalem. “In the long run we’d like to be able to see whether it’s children’s generosity that also makes parents more kind or the other way around. Probably it’s both.”
Eating more whole fresh fruit, especially blueberries, grapes, apples and pears, is linked to a lower risk of Type 2 diabetes, but drinking more fruit juice has the opposite effect, says a study.
British, US and Singaporean researchers pored over data from three big health investigations that took place in the United States, spanning a quarter of a century in all.
More than 187,000 nurses and other professional caregivers were enrolled.
Their health was monitored over the following years, and they regularly answered questionnaires on their eating habits, weight, smoking, physical activity and other pointers to lifestyle.
Around 6.5 percent of the volunteers developed diabetes during the studies.
People who ate at least two servings each week of certain whole fruits, especially blueberries, grapes and apples, reduced their risk of Type 2 diabetes by as much as 23 percent compared to those who ate less than one serving per month.
“Our findings provide novel evidence suggesting certain fruits may be especially beneficial for lower diabetes risk,” said Qi Sun, an assistant professor of nutrition at the Harvard School of Public Health.
On the other hand, those who consumed one or more servings of fruit juice each day saw their risk of the disease increase by as much as 21 percent.
Swapping three servings of juice per week for whole fruits resulted in a seven-percent reduction in risk, although there was no such difference with strawberries and cantaloupe melon.
The paper, published on Friday by the British Medical Journal (BMJ), says further work is needed to explore this “significant” difference.
It speculates that, even if the nutritional values of whole fruit and fruit juice are similar, the difference lies with the fact that one food is a semi-solid and the other a liquid.
“Fluids pass through the stomach to the intestine more rapidly than solids even if nutritional content is similar,” says the paper.
“For example, fruit juices lead to more rapid and larger changes in serum [blood] levels of glucose and insulin than whole fruits.”
The study also points to evidence that some kinds of fruit have a beneficial effect for health.
Berries and grapes, for instance, have compounds called anthocyanins which have been found to lower the risk of heart attacks.
But, say the authors, how or even whether this also applies to diabetes risks is for now unclear.
The investigation looked at data from the Nurses’ Health Study, which ran from 1984-2008; the Nurses’ Health Study II (1991-2009); and the Health Professionals Follow-Up Study (1986-2008).
Ten kinds of fruit were used in the questionnaire: grapes or raisins; peach, plums or apricots; prunes; bananas; cantaloupe melon; apples or pears; oranges; grapefruit; strawberries; and blueberries.
The fruit juices identified in the questionnaire were apple, orange, grapefruit and “other.” – AFP/Relaxnews, September 2, 2013.
A NEW study finds that eating a weekly portion of salmon or other fatty fish, such as trout or mackerel, could reduce your risk of developing rheumatoid arthritis by more than half.
In a study published Monday in the Annals of Rheumatic Diseases, the Karolinska Institute in Stockholm found that the omega-3 fatty acids in fish can cut the risk of chronic inflammatory disease by 52 percent.
Prior research from 2009 suggests that consuming fish oils could help reduce inflammation that leads to a variety of diseases, including rheumatoid arthritis. In this study, researchers highlighted the benefit to long-chain omega-3 polyunsaturated fatty acid (Pufa) content in fish.
If you prefer lean fish, such as cod or canned tuna, the same benefit could be found in eating four servings a week, the researchers found. Long-term, weekly consumption of any type of fish was associated with a 29 percent lower risk of the disease.
However you’ll need to sustain a regular diet of fish for at least 10 years to enjoy the health prevention against the condition, they added.
To reach their findings, head researcher Alicja Wolk and her team analyzed the diets of 32,232 Swedish born between 1914 and 1948. Subjects completed questionnaires about their food intake and lifestyle in 1987 and 1997. Women who consumed at least 0.21g of omega-3 Pufas daily had the 52 percent reduced risk, the study found. – AFP Relaxnews
A team of researchers said Wednesday that it had produced embryonic stem cells — a possible source of disease-fighting spare parts — from a cloned human embryo.
Scientists at the Oregon Health and Science University accomplished in humans what has been done over the past 15 years in sheep, mice, cattle and several other species. The achievement is likely to, at least temporarily, reawaken worries about “reproductive cloning” — the production of one-parent duplicate humans.
But few experts think that production of stem cells through cloning is likely to be medically useful soon, or possibly ever.
“An outstanding issue of whether it would work in humans has been resolved,” said Rudolf Jaenisch, a biologist at MIT’s Whitehead Institute in Cambridge, Mass., who added that he thinks the feat “has no clinical relevance.”
“I think part of the significance is technical and part of the significance is historical,” said John Gearhart, head of the Institute for Regenerative Medicine at the University of Pennsylvania. “Many labs attempted it, and no one had ever been able to achieve it.”
A far less controversial way to get stem cells is now available. It involves reprogramming mature cells (often ones taken from the skin) so that they return to what amounts to a second childhood from which they can grow into a new and different adulthood. Learning how to make and manipulate those “induced pluripotent stem” (IPS) cells is one of biology’s hottest fields.
Stem cells have the capability of maturing into different types of tissue depending on how they are stimulated. Embryonic stem cells (ESCs), plucked from a microscopic embryo, have the greatest potential. With the right molecular nudges, they could theoretically be used to grow new kidneys, lungs and hearts for use by people whose own organs have worn out.
Some experts think that “regenerative medicine” will eventually become an approach to healing that is as important as surgery or pharmacology.
The Oregon researchers, led by Shoukhrat Mitalipov, produced embryonic stem cells through “somatic cell nuclear transfer,” the technique used in 1996 to make Dolly the sheep the first cloned mammal.
The nucleus of a mature cell is transplanted into a human oocyte (egg) whose own nucleus has been removed. After the right stimulation, this new hybrid cell starts to divide and develop just as a sperm-fertilized egg would. When it is at the “blastocyst” stage — about 100 cells — its core contains a small number of embryonic stem cells capable of becoming any type of cell possessed by the human body.
But getting the doctored egg to grow even that far is extremely difficult. For some species, hundreds of eggs must be subjected to nuclear transfer before any produce viable embryonic stem cells. The failure of human oocytes to produce them had led some scientists to speculate that the technique simply might not work in people for some reason.
Mitalipov and several members of his team work at the Oregon National Primate Research Center and had refined their techniques using rhesus monkeys. They used nuclei from the skin cells of newborns or, in some cases, fetuses. Their stimulants included a pulse of electricity at the time of nuclear transfer and the addition of caffeine to the fluid cells lived in.
The tweaks and improvements apparently made all the difference. In one experiment, eight oocytes harvested from one woman produced five blastocysts and four embryonic stem cell lines — a success rate virtually unseen in other animals. The researchers subsequently proved cells were “pluripotent” by coaxing them to become, among other things, beating heart muscle cells.
The experiments were reported in a paper published online in the journal Cell.
“Where the kudos come is in being able to over time enhance and improve the technology developed in other species to make this amenable to the human oocyte,” Gearhart said.
The blastocysts could be implanted in a woman’s uterus. It might develop into a fetus. Most cloned animals, however, turn out to have major health problems and shortened lives.
“We just need to make sure it’s clear to the public that no one in their right mind would want to do that. There is no intent to do reproductive cloning. None at all,” Gearhart said.
Are these embryonic stem cells more versatile than IPS cells made by reprogramming skin cells?
“That’s of interest,” Jaenisch said. But whatever the answer, “the consequence would be to make the IPS cells better.” Given the difficulty of obtaining human oocytes, and the controversial nature of the research, embryonic stem cells aren’t likely to ever be the preferred tool of regenerative medicine, he said.
Source: Washington Post
A chemical found in red meat helps explain why eating too much steak, mince and bacon is bad for the heart, say US scientists.
A study in the journal Nature Medicine showed that carnitine in red meat was broken down by bacteria in the gut.
This kicked off a chain of events that resulted in higher levels of cholesterol and an increased risk of heart disease.
Dieticians warned there may be a risk to people taking carnitine supplements.
There has been a wealth of studies suggesting that regularly eating red meat may be damaging to health.
In the UK, the government recommends eating no more than 70g of red or processed meat a day – the equivalent of two slices of bacon.
Saturated fat and the way processed meat is preserved are thought to contribute to heart problems. However, this was not thought to be the whole story.
“The cholesterol and saturated fat content of lean red meat is not that high, there’s something else contributing to increases in cardiovascular risk,” lead researcher Dr Stanley Hazen told the BBC.
Experiments on mice and people showed that bacteria in the gut could eat carnitine.
Carnitine was broken down into a gas, which was converted in the liver to a chemical called TMAO.
In the study, TMAO was strongly linked with the build-up of fatty deposits in blood vessels, which can lead to heart disease and death.
Dr Hazen, from the Cleveland Clinic, said TMAO was often ignored: “It may be a waste product but it is significantly influencing cholesterol metabolism and the net effect leads to an accumulation of cholesterol.
“The findings support the idea that less red meat is better.
“I used to have red meat five days out of seven, now I have cut it way back to less than once every two weeks or so.”
He said the findings raised the idea of using a probiotic yogurt to change the balance of bacteria in the gut.
Reducing the number of bacteria that feed on carnitine would in theory reduce the health risks of red meat.
Vegetarians naturally have fewer bacteria which are able to break down carnitine than meat-eaters.
Sausages, ham, bacon and other processed meats appear to increase the risk of dying young, a study of half a million people across Europe suggests.
It concluded diets high in processed meats were linked to cardiovascular disease, cancer and early deaths.
The researchers, writing in the journal BMC Medicine, said salt and chemicals used to preserve the meat may damage health.
The British Heart Foundation suggested opting for leaner cuts of meat.
The study followed people from 10 European countries for nearly 13 years on average.
It showed people who ate a lot of processed meat were also more likely to smoke, be obese and have other behaviours known to damage health.
However, the researchers said even after those risk factors were accounted for, processed meat still damaged health.
One in every 17 people followed in the study died. However, those eating more than 160g of processed meat a day – roughly two sausages and a slice of bacon – were 44% more likely to die over a typical follow-up time of 12.7 years than those eating about 20g.
In total, nearly 10,000 people died from cancer and 5,500 from heart problems.
Prof Sabine Rohrmann, from the University of Zurich, told the BBC: “High meat consumption, especially processed meat, is associated with a less healthy lifestyle.
“But after adjusting for smoking, obesity and other confounders we think there is a risk of eating processed meat.
“Stopping smoking is more important than cutting meat, but I would recommend people reduce their meat intake.”
She said if everyone in the study consumed no more than 20g of processed meat a day then 3% of the premature deaths could have been prevented.
The UK government recommends eating no more than 70g of red or processed meat – two slices of bacon – a day.
A spokesperson said: “People who eat a lot of red and processed meat should consider cutting down.”
However a little bit of meat, even processed meat, had health benefits in the study.
Ursula Arens from the British Dietetic Association told BBC Radio 4′s Today programme that putting fresh meat through a mincer did not make it processed meat.
“Something has been done to it to extend its shelf life, or to change its taste, or to make it more palatable in some way… and this could be a traditional process like curing or salting.”
She said even good quality ham or sausages were still classed as processed meat, while homemade burgers using fresh meat were not.
“For most people there’s no need to cut back on fresh, red meat. For people who have very high intake of red meat – eat lots of red meat every day – there is the recommendation that they should moderate their intake,” she added.
Ms Arens also confirmed that the study’s finding that processed meat was linked to heart disease was new.
Mr Roger Leicester, a consultant surgeon and a member of the Meat Advisory Panel, said: “I would agree people should eat small quantities of processed meat.”
However, he said there needed to be a focus on how meat was processed: “We need to know what the preservatives are, what the salt content is, what the meat content is…meat is actually an essential part of our diet.”
Dr Rachel Thompson, from the World Cancer Research Fund, said: “This research adds to the body of scientific evidence highlighting the health risks of eating processed meat.
“Our research, published in 2007 and subsequently confirmed in 2011, shows strong evidence that eating processed meat, such as bacon, ham, hot dogs, salami and some sausages, increases the risk of getting bowel cancer.”
The organisation said there would be 4,000 fewer cases of bowel cancer if people had less than 10g a day.
“This is why World Cancer Research Fund recommends people avoid processed meat,” said Dr Thompson.
Tracy Parker, a heart health dietitian with the British Heart Foundation, said the research suggested processed meat might be linked to an increased risk of early death, but those who ate more of it in the study also made “other unhealthy lifestyle choices”.
“Red meat can still be enjoyed as part of a balanced diet.
“Opting for leaner cuts and using healthier cooking methods such as grilling will help to keep your heart healthy.
“If you eat lots of processed meat, try to vary your diet with other protein choices such as chicken, fish, beans or lentils.”
Source: BBC Health
OTTAWA, Feb 27 – Volunteer work has long been touted as good for the soul, but the practice is also good for your heart, according to a study out Monday in the journal JAMA Pediatrics.
Researchers at the University of British Columbia in Vancouver wanted to find out how volunteering might impact one’s physical condition, and discovered that it improves cardiovascular health, said study author Hannah Schreier.
And “the volunteers who reported the greatest increases in empathy, altruistic behavior and mental health were the ones who also saw the greatest improvements in their cardiovascular health,” said Schreier.
Previous studies had shown that psychosocial factors, such as stress, depression and well being, play a role in cardiovascular disease, which is a leading cause of death in North America.
Schreier noted that the first signs of the disease can begin to appear during adolescence, which is why she recruited young volunteers for her study.
She and her team measured the body mass index, inflammation and cholesterol levels of 53 Vancouver high school students who spent an hour a week working with elementary school children in after-school programs in their neighborhood.
They compared the results with a group of 53 students who were waitlisted for the volunteering program.
The researchers also assessed the teenagers’ self-esteem, mental health, mood, and empathy.
After 10 weeks the volunteers had lower levels of inflammation and cholesterol and less body fat than those on the waitlist. – AFP-Relaxnews