Wednesday, May 13, 2015

Study links PTSD to premature aging

Individuals with post-traumatic stress disorder may be at greater risk for premature aging. This is according to a new study published in the American Journal of Geriatric Psychiatry.

An aging woman
Researchers found people with PTSD were more likely to have shorter telomere length - an indicator of premature aging.
Around 7-8% of the US population will experience post-traumatic stress disorder (PTSD) at some point in their lives.
The condition can occur after exposure to a traumatic event. A person with PTSD may experience nightmares, have flashbacks of the event, avoid places or situations that remind them of the event and suffer hyperarousal symptoms - such as nervousness and tension.
PTSD has been associated with increased risk of numerous other health problems, including insomnia, severe depression, eating disorders and substance abuse.
This latest study, conducted by researchers from the University of California-San Diego School of Medicine and the Veterans Affairs San Diego Health System, is the first of its kind to associate PTSD with a biological process like premature aging.
To reach their findings, the team conducted a comprehensive review of studies connected to early aging among individuals with PTSD dating back to 2000.
Since there is no standard definition for premature or accelerated aging, the researchers say, they looked at nonpsychiatric disorders that incorporate early aging, such as progeria syndrome and Down's syndrome, as a guide.
The team identified 64 studies that they deemed appropriate for investigation into the link between PTSD and aging. They were able to use these studies to assess how PTSD affects biomarkers of accelerated aging - such as telomere length - and how it affects onset and prevalence of age-related medical conditions and overall mortality.

PTSD linked to shorter telomere length, earlier mortality

The researchers found that, compared with individuals without PTSD, people with the condition had reduced telomere length.
Telomeres are caps on the end of each DNA strand that protect the chromosomes. Telomere length reduces with each cell replication and this is considered to be a marker of aging.
The team also found that people with PTSD were more likely to have increased levels of pro-inflammatory markers, such as C-reactive protein (CRP) and tumor necrosis factor alpha (TNFα), which are said to be markers of aging.
There was also a high incidence of PTSD alongside age-related conditions, the team notes, such as cardiovascular disease, type 2 diabetes and dementia.
What is more, some of the studies reviewed suggested a mild-to-moderate link between PTSD and earlier mortality, which the team says is consistent with premature or accelerated aging among people with the condition.
Though the researchers say their study does not show whether PTSD is a specific cause of premature aging, they believe it highlights the need to class PTSD as more than just a mental illness.
First study author Dr. James B. Lohr, professor of psychiatry at UC-San Diego, adds:
"Early senescence, increased medical morbidity and premature mortality in PTSD have implications in health care beyond simply treating PTSD symptoms. Our findings warrant a deeper look at this phenomenon and a more integrated medical-psychiatric approach to their care."
The team stresses that further studies are needed to confirm their findings and determine the mechanisms behind the association between PTSD and premature aging.
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Soda and fruit juice are 'biggest culprits in dental erosion'

Soft drinks are the most significant factor in severity of dental erosion, according to a new study published in the Journal of Public Health Dentistry.

cans of soda
The most severe cases of dental erosion in the study were among people who regularly drank sugary soft drinks and fruit juices.
Dental erosion is when enamel - the hard, protective coating of the tooth - is worn away by exposure to acid. The erosion of the enamel can result in pain - particularly when consuming hot or cold food - as it leaves the sensitive dentine area of the tooth exposed.
The enamel on the tooth becomes softer and loses mineral content when we eat or drink anything acidic. However, this acidity is cancelled out by saliva, which slowly restores the natural balance within the mouth. But if the mouth is not given enough time to repair itself - because these acid attacks are happening too often - the surface of the teeth is worn away.
Anything with a pH value (the measure of acidity) lower than 5.5 can damage the teeth. Diet and regular sodas, carbonated drinks, flavored fizzy waters, sports drinks, fruit and fruit juices are all known to be harmful to teeth if they are consumed too often.

Study finds that a 'substantial proportion' of adults have dental erosion

The study finds that a substantial proportion of adults show some evidence of dental erosion, with the most severe cases being among people who drink sugary soft drinks and fruit juices.
Examining 3,773 participants, the researchers found 79% had evidence of dental erosion, 64% had mild tooth wear, 10% had moderate tooth wear and 5% displayed signs of severe tooth wear. The participants in the study with moderate and severe tooth wear consumed more soft drinks and fruit juices each day than the other groups.
Among participants with lower levels of tooth wear, the researchers found that milk was a more popular drink than soda or fruit juice.
Men were also found to be at twice the risk for dental erosion as women, and tooth wear became more severe with age among the participants.
Commenting on the study, Dr. Nigel Carter OBE, chief executive of the British Dental Health Foundation, says that while fruit juice may be a nutritious drink, the high concentrations of sugar and acid can lead to severe dental damage if these drinks are consumed often each day.
"Water and milk are the best choices by far, not only for the good of our oral health but our overall health too," says Dr. Carter. "Remember, it is how often we have sugary foods and drinks that causes the problem so it is important that we try and reduce the frequency of consumption."
He adds:
"Dental erosion does not always need to be treated. With regular check-ups and advice your dental team can prevent the problem getting any worse and the erosion going any further. The more severe cases of tooth wear can often result in invasive and costly treatment so it is important that we keep to a good oral hygiene routine to make sure these future problems do not arise."
Many sodas and fruit juices contain at least six teaspoons of sugar, and as they often come in portions that are larger than recommended, they can lead to tooth decay as well as dental erosion.
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Stroke: not just an adult's condition

When you hear the word "stroke," the first picture that pops into your mind is likely to be of an elderly individual. It's true that older adults are at greater stroke risk; the chance of having a stroke doubles with each decade of life after the age of 55. But did you know that infants and children can also suffer stroke? It can even occur before birth.

An X-ray of a stroke in a child
Stroke affects 6 in every 100,000 children in the US and is one of the 10 leading causes of death among children in the country.
According to the National Stroke Association, stroke affects 6 in every 100,000 children in the US. It is also one of the 10 leading causes of death among children in the country.
The rate of stroke is much higher in adults than children. Every year, more than 795,000 men and women suffer a stroke and around 130,000 die from the condition. However, studies have found stroke rates are on the rise in children in the US.
In 2011, a study published in the Annals of Neurologyreported a 51% increase in ischemic stroke incidence among boys aged 5-14 from the period 1995-96 to 2007-08, while girls aged 5-14 saw a 3% rise in ischemic stroke in the same period.
In many ways, stroke in children - commonly referred to as pediatric stroke - can present more challenges than stroke in adults.
The early signs of stroke in children are much more subtle than in adults, meaning they often go unrecognized. According to the International Alliance for Pediatric Stroke (IAPS), newborns who suffer stroke may not even begin to show any symptoms until the age of 4-8 months.
What is more, because parents, caregivers and even health care professionals do not often associate stroke with children, it may be ruled out as a possibility. As a result, many children fail to receive adequate treatment.
A 2014 study conducted by Dr. Mark Mackay, director of the Children's Stroke Program at the Royal Children's Hospital and Murdoch Children's Research Institute in Melbourne, Australia, and colleagues found that only half of interviewed parents whose children suffered stroke thought their child's symptoms were serious enough to call 911, while 21% of parents adopted a "wait-and-see" approach. What is more, only 36% considered stroke as a possible cause of their child's symptoms.
As with most health conditions, early treatment for stroke is key. Unfortunately, around 20-40% of children die after a stroke, and of those who do survive, around 50-80% will have lifelong neurological problems, such a partial or total paralysis.
May is American Stroke Awareness Month. In this Spotlight, we investigate the risk factors for pediatric stroke, the signs and symptoms to look out for, as well as the treatment options for the condition.

Perinatal stroke and childhood stroke

There are two types of pediatric stroke: perinatal stroke and childhood stroke.
Perinatal stroke, also referred to as fetal or prenatal stroke, occurs between the last 18 weeks of pregnancy and the first 30 days of birth. In the US, perinatal stroke occurs in about 1 in every 2,800 live births.
Most cases of perinatal stroke are ischemic, caused by blood clots breaking off from the placenta and becoming lodged in the child's brain.
Childhood stroke occurs between the ages of 1 month and 18 years. Unlike adults, in whom ischemic stroke is most common, children are equally as likely to have ischemic stroke as they are hemorrhagic stroke - caused by a brain bleed from a ruptured blood vessel.
Around 60% of all pediatric strokes occur in boys, and African-American children are at greater stroke risk than Caucasian and Asian children.

The risk factors for pediatric stroke

Among adults, high blood pressure, irregular heartbeat and atherosclerosis - hardening of the arteries - are some of the most common risk factors for stroke. These factors rarely cause stroke in children, however.
According to the American Stroke Association, around half of all pediatric strokes are triggered by an underlying condition, most commonly sickle cell disease - an inherited blood disorder - and congenital heart disease.
Other underlying conditions that may raise a child's stroke risk include head and neck infections, abnormal blood clotting, head trauma and systemic conditions, such as autoimmune disorders.
Maternal history of infertility, premature rupture of membranes during pregnancy, maternal preeclampsia and chorioamnionitis - inflammation of the fetal membranes due to a bacterial infection - may also increase a child's stroke risk.
Though cardiovascular-related risk factors for stroke in adults are rare in children, recent studies have indicated an increase in these risk factors among the younger population. This is down to a rise in high blood pressure, obesity,diabetes, high cholesterol and tobacco and alcohol use among youth.
A 2014 study published in the journal Neurology also suggested colds and other minor infections in childhood may temporarily raise a child's stroke risk.
"We've seen this increase in stroke risk from infection in adults, but until now, an association has not been studied in children," commented study author Dr. Heather Fullerton, director of the University of California-San Francisco Pediatric Stroke and Cerebrovascular Disease Center.
"It is possible that inflammatory conditions contribute more to the stroke risk in children, however, further research is needed to explore this possible association."
It is important to note, however, that in around half of all childhood stroke cases, no previous risk factor can be determined.

What are the signs and symptoms to look out for?

As mentioned previously, it can be very hard to spot stroke symptoms among very young children. Around 40% of infants do not show symptoms of early stroke; a parent may not know their baby has suffered stroke until months later when they show reduced movement or weakness on one side of their face.
A child with a headache
As well as weakness or numbness on one side of the body, other signs of stroke in children may include severe headache, dizziness and vomiting.
Repetitive twitching of the face, arm or leg can be an indicator of stroke in newborns, as can a pause in breathing alongside prolonged staring and extreme fatigue.
As children develop, the signs of symptoms of stroke are very similar to those in adults. Weakness or numbness on one side of the body and problems speaking or understanding language - such as slurred speech or problems understanding simple instructions - may be signs of stroke.
Other signs of stroke among children may include severe headache, vomiting, fatigue, severe dizziness and appearance of seizures.
The American Stroke Association stress that the F.A.S.T. acronym is an easy way to remember the sudden signs of stroke in both children and adults:
  • Face drooping. Is one side of the face numb or drooping? Is the individual able to smile?
  • Arm weakness. Is one arm numb or weak? Ask the individual to lift both arms. Does one arm drift downward?
  • Speech difficulty. Is the individual's speech slurred? Do they find it hard to speak or are they hard to understand? Can they correctly repeat a simple sentence, such as "the sky is blue?"
  • Time to call 911. If the individual shows any of these symptoms, call 911 immediately, even if the symptoms disappear. Check the time at which first symptoms appear.
"Think stroke, act fast and call 911. That message applies to adults and children," says Dr. MacKay. "Getting to the hospital quickly is an essential first step to develop strategies to improve access to emergency treatment in children."

Treatment options for pediatric stroke

For adults suffering ischemic stroke, the first port of call in terms of treatment is the medication tissue plasminogen activator (tPA), which works by dissolving any blood clots that are blocking the arteries, restoring blood flow to the brain. Such treatment must be administered within 3 hours of symptom onset - 4.5 hours for some patients.
The use of tPA among young children with ischemic stroke, however, is controversial. Since children and adults have physiological differences, health care professionals are concerned about the drug's safety and efficacy among children - something that is currently being investigated.
As such, stroke treatment for children tends to vary depending on the cause of their stroke and any underlying medical conditions they may have. A child whose stroke was caused by a heart defect, for example, may be treated with blood-thinning medication, such as warfarin or aspirin.
Children who suffer stroke have around a 15-18% chance of suffering another stroke. Therefore, many children may receive treatment to prevent stroke recurrence, such as antithrombotic therapy - medication that stops blood clots from forming or growing.
One crucial treatment for the majority children who suffer stroke is rehabilitation therapy, which can involve physiotherapy, occupational therapy and speech therapy.
Sixty percent of children experience neurological problems, such as hemiplegia or hemiparesis cerebral palsy, following stroke. Rehabilitation therapy can really help reduce the neurological effects of stroke, and the earlier treatment is started, the more likely it is to succeed.

Severe delays in diagnosis of pediatric stroke

But as Dr. MacKay's study showed, many parents either do not consider the possibility that their child is suffering a stroke or are unable to recognize the signs, which can severely delay treatment.
Dr. MacKay's findings revealed that the average time from symptom onset of pediatric stroke to arrival at the emergency room was 1.8 hours, with some arrivals taking up to 4 hours.
And it is not only parents who may overlook the signs and symptoms of pediatric stroke - doctors can too. Studies have found that in the US, it can often take longer than 24 hours to diagnose stroke in children.
report from ABC News in 2011 provides evidence of this, revealing how it took more than 25 hours for doctors to diagnose a 15-year-old boy from Ohio with stroke.
Because of the delay in diagnosis, the boy had to have a part of his skull removed to ease pressure from the build up of blood in his brain.
In a 2008 interview, Dr. Fullerton said she believes a delay in diagnosis of pediatric stroke has fallen into a gap in clinical care. "It is a rare disorder in general, and so most child neurologists will not be very comfortable in caring for children with stroke," she said, adding:
"Stroke is considered more a disease of adults, but then adult stroke neurologists aren't familiar of the etiologies of stroke in children or how to manage stroke in children, and so they're often uncomfortable with caring for a stroke in a child.
It can be difficult to diagnose the etiology of their strokes. It often takes sophisticated imaging studies and studies that are done by very experienced practitioners. It really often does take a team approach to figure out why a child has had a stroke and figure out what is the best way to prevent more strokes in that child."
While stroke is much rarer in children than adults, it is important that parents, caregivers and health care professionals are aware that children can be affected by the condition and take note of the signs and symptoms that may arise.
Not only is May American Stroke Awareness Month, 2nd-8th May is dedicated to World Pediatric Stroke Awareness Week. Set up by the IAPS and not-for-profit organization Brendon's Smile last year, the campaign aims to raise awareness of pediatric stroke around the globe and educate communities about how the condition can impact children's lives.
Visit the IAPS website to find out more about pediatric stroke and how you can help raise awareness of the condition.
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Does having more sex make you less happy?

 The suggestion that sex boosts happiness has been made time and time again both in research papers and popular writing on the subject, such as self-help books. Now, a new study from researchers at Carnegie Mellon University in Pittsburgh, PA, goes against conventional wisdom to cast doubt on the theory that the more sex we have, the happier we are.

unhappy couple in bed
The researchers believe that the group instructed to have more sex reported lower levels of happiness because the couples were required to have more sex as part of the study, rather than them initiating it naturally.
In 2013, a study published in Social Indicators Researchfound that people reported steadily higher levels of happiness with increasing sexual frequency. And people who believed they were having less sex than their peers reported being less happy than those who believed they were having as much or more sex than their peers.
That study found that people who had sex once a week were 44% more likely to report a higher level of happiness compared with peers who had no sex in the previous year, and people who had sex up to three times a week were 55% more likely to report higher levels of happiness.
While the team behind the 2013 study used national survey data and statistical analyses to arrive at its conclusions, the Carnegie Mellon (CMU) researchers behind the new study recruited 128 healthy, married individuals between the ages of 35 and 65 who were in male-female couples in an attempt to investigate how sexual frequency affects happiness,.
The couples were randomly assigned into either a group that was asked to double the frequency of their weekly sexual intercourse or a group that received no instructions on sexual frequency.
At the start of the study - the results of which are published in the Journal of Economic Behavior & Organization - the participants completed surveys to establish baselines on health behaviors, happiness levels and occurrence, type and pleasure received from sex.
The couples also completed online questionnaires measuring these variables every day during the 3-month experimental period of the study. An exit survey was also completed to compare against the baseline results.
The CMU team found that the couples instructed to have more sex reported a small decrease in happiness, lower sexual desire and decreased enjoyment from sex.
However, the researchers believe that this lowered happiness was not simply caused by having more sex, but by the fact the couples were required to have more sex as part of the study, without them initiating it naturally.

Authors still believe that couples do not have enough sex

George Loewenstein, the study's lead investigator and the Herbert A. Simon University Professor of Economics and Psychology in the Dietrich College of Humanities and Social Sciences, explains:
"Perhaps couples changed the story they told themselves about why they were having sex, from an activity voluntarily engaged in to one that was part of a research study. If we ran the study again, and could afford to do it, we would try to encourage subjects into initiating more sex in ways that put them in a sexy frame of mind, perhaps with babysitting, hotel rooms or Egyptian sheets, rather than directing them to do so."
Interestingly, Prof. Loewenstein believes that the majority of couples have less sex than is good for them and considers increasing sexual frequency to be beneficial for most couples.
"The desire to have sex decreases much more quickly than the enjoyment of sex once it's been initiated," adds Tamar Krishnamurti, a research scientist in CMU's Department of Engineering and Public Policy.
"Instead of focusing on increasing sexual frequency to the levels they experienced at the beginning of a relationship," elaborates Krishnamurti, "couples may want to work on creating an environment that sparks their desire and makes the sex that they do have even more fun."
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Live Ebola virus detected in survivor's eye months after recovery

Survivors of Ebola virus disease can develop health complications that persist after recovery. Now, a new study of an Ebola survivor describes how the virus remained live in the fluid within one of his eyes for more than 2 months after recovery.

woman having eye exam
The researchers say Ebola disease survivors should be monitored for eye and other health complications after recovery.
The researchers behind the study note that while they found viable Ebola virus in the aqueous humor of the patient's affected eye, tests on tear fluid and conjunctiva samples tested negative for Ebola, suggesting casual contact with Ebola survivors does not pose a risk.
However, they warn that their findings do show a need for infection control when patients who have survived Ebola undergo any invasive procedures in their eyes.
They also note the study highlights the importance of follow-up care for people who have survived infection with Ebola virus.
The team reports the research in the New England Journal of Medicine and presented it at the 2015 Association for Research in Vision and Ophthalmology (ARVO) annual meeting in Denver, Colorado.

Ebola survivors 'require ongoing medical care'

First author and infectious disease specialist Jay Varkey, an assistant professor of medicine at Emory University School of Medicine in Atlanta, GA, says the current Ebola outbreak in West Africa has resulted in the largest number of Ebola survivors in history.
He explains that Ebola survivors "require ongoing medical care to manage complications from the infection that may develop during recovery."
In their paper, Prof. Varkey and colleagues describe the case of 43-year-old Ian Crozier, a Zimbabwe-born doctor and American citizen who became infected with Ebola virus while working at an Ebola treatment center in Sierra Leone.
He was transported to the US and underwent 40 days of treatment in the Serious Communicable Disease Unit at Emory University Hospital.
During his recovery, it was clear that Dr. Crozier had acute uveitis and severe high pressure in one eye.
Uveitis is an inflammation of the middle layer of the eye, which includes the iris - the ring of muscle behind it - and a layer of tissue that supports the retina. It causes redness, blurred vision, eye pain, headaches and sensitivity to light.

Viable Ebola virus persisted in aqueous humor for more than 2 months

Two months after his discharge from the hospital, Dr. Crozier had a full eye exam at the Emory Eye Center. The exam included removal of fluid from inside the eye - a procedure known as "anterior chamber paracentesis."
The results showed he had viable Ebola virus in the aqueous humor of the inflamed eye. This was 9 weeks after the virus had cleared from his bloodstream.
Dr. Crozier was treated with topical corticosteroids and other medications to reduce the higher pressure in his eye. His eyesight has returned to normal following treatment for uveitis and he is continuing to have regular eye exams.
The authors conclude their findings have implications not only for Ebola virus disease (EVD) survivors but also for health care providers who have been sent home for ongoing care. They call for ongoing surveillance for the development of diseases in the eye and other parts of the body in the period following the Ebola outbreak, as Prof. Varkey explains:
"To safely evaluate and treat EVD survivors who develop complications in the eye and other 'immune-privileged' sites of the body, health care providers who perform invasive procedures should develop standard operating protocols for: 1. Safely donning and doffing PPE [personal protection equipment]; 2. Handling laboratory specimens, and 3. Managing medical waste."
Meanwhile, Medical News Today recently reported how leaders of the World Health Organization admitted to faults in their handling of the Ebola outbreak in West Africa. They say they have learned eight valuable lessons from the crisis, including the fact that current national and international capacities and systems cannot cope with large-scale outbreaks.
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Healthy diets make brighter brains

A study following nearly 28,000 people aged 55 and older at high cardiovascular risk, which monitored their diets for 5 years and tested declines against thinking and memory tests, found a smaller drop in brain power for those who ate well.

[fish and vegetables]
Fish was part of healthy eating while red meat was among the unhealthy foods.
The American Academy of Neurology has published the results in the journal Neurology. The healthy eating linked to the stronger cognitive health was a diet with not much red meat, moderate alcohol and lots of fruits and vegetable, nuts and fish.
The 27,860 over-55s included for the analysis, from across 40 countries, were studied over an average of around 5 years.
Certain health conditions were excluded at the start of the study of people at high risk of cardiovascular disease. None of the participants had diabetes or a history of heart disease, stroke or peripheral artery disease; nor had any recently experienced serious disease outcomes such as a stroke or congestive heart failure.
Participants who experienced heart disease or stroke during the study were no longer followed for diet and mental power.
To take a baseline measure of cognitive health and monitor any decline, thinking and memory skills were tested at the start of the study, then 2 years and about 5 years later.
A maximum of 30 points was possible against these thinking and memory tests and cognitive decline was noted when scores dropped by 3 points or more, which happened for 17% overall - a total of 4,699 participants.

Cognitive decline lowest among those who reported healthiest diets

The proportion registering a decline was lower for people reporting the healthiest diets - 14% of these showed a drop in thinking and memory, compared with 18% of the people eating the least healthy diets.
Measuring cognitive health
This new study linking brain power and diet involved a test of cognitive health that is used during dementia diagnosis. The mini mental state examination (MMSE) measures:
  • Orientation to time and place
  • Word recall
  • Language abilities
  • Attention and calculation
  • Visuospatial skills.
For the measure of diet, the participants were asked at the start of the study to say how often they ate certain foods, including vegetables, nuts and soy proteins, whole grains and deep-fried foods. They also reported levels of alcohol intake and gave data to produce a ratio of fish to meat and eggs in their diets.
The measure of diet quality was a modified version of the healthy eating index used by the US government.
Among the 5,687 people with the healthiest diet, 782 made up the 13.8% having cognitive decline, while of the 5,459 people with the least healthy diets, 987 accounted for the 18.1%.
The relative difference from these figures produces a 24% lower likelihood of a drop in thinking and memory for people eating well.
The researchers accounted for factors that could have affected the results, such as physical activity, high blood pressure and history of cancer.
Study author Dr. Andrew Smyth, of McMaster University in Hamilton, Ontario, Canada, and the National University of Ireland in Galway, says diet in later life is only part of the picture:
"Adoption of a healthy diet probably begins early in life, and a healthy diet might also go along with adoption of other healthy behaviors."
For their data, the authors examined participants from randomized drug trials in cardiovascular disease supported by pharmaceutical company Boehringer Ingelheim.
In background to their work, the authors cite previous brain health links to healthy diet but point out that using the large multinational prospective cohort study allows observation of "more precise associations between diet (assessed using standardized methodology) and cognitive outcomes."
Explaining what biological explanations may lie behind the emerging evidence, the authors say: "Dietary intake may modify the risk of cognitive decline through multiple mechanisms, including increased risk of stroke (both overt and covert) and through deficiency of nutrients required for neuronal regeneration (for example, group B vitamins, and vitamin C)."
The risk factors for dementia listed by the US National Institute of Neurological Disorders and Stroke includes a number that can be modified by dietary and lifestyle measures.
The new study ends by stating:
"In conclusion, we report that higher diet quality is associated with a reduced risk of cognitive decline. Improved diet quality represents an important potential target for reducing the global burden of cognitive decline."
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Could high blood sugar be a cause of Alzheimer's disease?

While nobody knows exactly what causes the complex brain changes that lead to Alzheimer's disease, scientists suspect one of the drivers is the accumulation of plaques of a faulty protein called beta-amyloid. Now, a new study of mice shows how too much sugar in the blood can speed up the production of the protein.

The researchers suggest their findings will lead to new treatments that reduce the harmful effects of high blood sugar on the brain.
Earlier studies have pointed to diabetes - where the body fails to control high blood sugar naturally with insulin - as a possible contributor to Alzheimer's disease, but the new study links high blood sugar itself to beta-amyloid.
Researchers from the School of Medicine at Washington University in St. Louis (WUSTL) report their findings inThe Journal of Clinical Investigation.
Lead author and postdoctoral research scholar Dr. Shannon Macauley says:
"Our results suggest that diabetes, or other conditions that make it hard to control blood sugar levels, can have harmful effects on brain function and exacerbate neurological conditions such as Alzheimer's disease."
She and her colleagues suggest their finding could lead to new treatment targets to reduce the harmful effects of high blood sugar on the brain.

Doubling of blood glucose led to 20% higher levels of beta-amyloid

For their study, the team used mice bred to develop a condition that is like Alzheimer's in humans - as they age their brains accumulate amyloid plaques.
When they infused glucose into the bloodstream of young mice, they found their brains produced beta-amyloid faster. A doubling of blood glucose led to 20% higher levels of beta-amyloid compared with mice that had normal blood glucose levels.
When the team repeated the experiment in older mice that already had amyloid plaques in their brains, beta-amyloid levels rose by 40%.
Closer examination revealed that sudden elevation of blood sugar increased brain cell activity, which stimulates them to make more beta-amyloid.
The team found that openings called KATP channels were an important feature of increased beta-amyloid. These ATP-sensitive potassium channels sit on the surface of brain cells and close when glucose levels get too high. When the channels are closed, the neurons are more likely to fire.
Under normal conditions, neurons fire to encode and send information - a basic function essential for learning and memory. But too much firing in certain areas of the brain increases beta-amyloid, which makes it more likely that plaques will form and encourage the development of Alzheimer's, the authors suggest.

KATP channel 'directly links glucose, brain cell activity and beta-amyloid'

In a final set of experiments, the team injected diazoxide straight into the brains of mice (to bypass the blood brain barrier). Diazoxide is a glucose-elevating drug that is used to treat low blood sugar.
The drug forced the KATP channels to stay open as glucose levels rose. Under these conditions, the brain cells produced beta-amyloid at the normal rate - it did not speed up.
The team concludes this result shows that the KATP channel directly links glucose levels with brain cell activity and rate of beta-amyloid production.
The researchers are already exploring the link further using diabetes drugs in Alzheimer's-like mice.
KATP channels feature in all kinds of cells, not just brain cells. For example, they feature in the pancreatic cells that make insulin - the enzyme the body uses to control blood sugar.
Commenting on the contribution of their findings, Dr. Macauley says:
"This observation opens up a new avenue of exploration for how Alzheimer's disease develops in the brain as well as offers a new therapeutic target for the treatment of this devastating neurologic disorder."
She and her colleagues are also looking into how raised glucose levels may interfere with how different parts of the brain work together in cognitive functioning.
Funds for the study came from the National Institutes of Health, the National Science Foundation and the JPB Foundation.
Meanwhile, Medical News Today recently learned how scientists at Johns Hopkins University found a molecule that links high blood sugar to metabolic disease. Writing in the Proceedings of the National Academy of Sciences, the team says the discovery could lead to new ways to prevent and treat diabetes.
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