Beta-blockers ‘may lower dementia risk’

By , January 8, 2013 11:48 pm

Beta-blockers ‘may lower dementia risk’

Beta-blockers Beta-blockers slow heart rate to reduce workload and help the heart pump more efficiently

Taking beta-blocker drugs may cut the risk of dementia, a trial in 774 men suggests.

The medication is used to treat high blood pressure, a known risk factor for dementia.

In the study, which will be presented at the American Academy of Neurology’s annual meeting in March, men on beta-blockers were less likely to have brain changes suggestive of dementia.

Experts say it is too early to recommend beta-blockers for dementia.

The findings are preliminary and larger studies in men and women from different ethnicities are needed to see what benefit beta-blockers might offer.

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These results are exciting, especially since beta blockers are a common treatment for high blood pressure”

Study author Dr Lon White Pacific Health Research and Education Institute in Honolulu

People with high blood pressure are advised to see their doctor and get their condition under control to prevent associated complications like heart disease, stroke and vascular dementia.

Brain blood flow

Having high blood pressure may damage the small vessels that supply the brain with blood.

Blood carries essential oxygen and nourishment to the brain and without it, brain cells can die.

Vascular dementia is the second most common cause of dementia after Alzheimer’s disease and can occur if blood flow to the brain is reduced.

Other research in a much larger sample of men – 800,000 in all – suggests another type of blood pressure drug known as an angiotensin receptor blocker (ARB) may cut dementia risk, including Alzheimer’s disease, by as much as 50%.

The latest work in 774 Japanese-American men found that all types of blood pressure medication were better than no treatment in terms of signs of dementia in the brain – brain shrinkage and tiny areas of brain tissue damage caused by poor blood supply – noted at autopsy after death.

However, men who had received beta-blockers as their only blood pressure medication had fewer abnormalities in their brains than those who had not been treated for their hypertension, or who had received other blood pressure medications, the University of Hawaii team found.

Men on beta-blockers and other medications also had fewer brain abnormalities, but not as big a reduction as that seen in the men on beta-blockers alone.

In the study, 610 of the men had high blood pressure or were being treated for high blood pressure.

Study author Dr Lon White said: “With the number of people with Alzheimer’s disease expected to grow significantly as our population ages, it is increasingly important to identify factors that could delay or prevent the disease.

“These results are exciting, especially since beta-blockers are a common treatment for high blood pressure.”

Dr Simon Ridley, head of research at Alzheimer’s Research UK, said: “Hypertension is a known risk factor for Alzheimer’s and other causes of dementia, and keeping high blood pressure in check could be important for preventing these diseases.

“This study suggests a link between the use of beta-blockers and fewer signs of dementia, but as the results of this study have yet to be published in full, it’s not clear what caused this link. It’s important to note that this study only looked at Japanese-American men, and these results may not be applicable to the wider population.

He said a better understanding of the links between high blood pressure and dementia could be crucial for developing new treatments or approaches to prevention.

“With 820,000 people affected by dementia in the UK, and that number increasing, we urgently need to find ways to prevent the diseases that cause it – that requires a massive investment in research,” Dr Ridley added.

Totally blind mice get sight back

By , January 8, 2013 11:47 pm

Totally blind mice get sight back

By James Gallagher Health and science reporter, BBC News

Eye

Totally blind mice have had their sight restored by injections of light-sensing cells into the eye, UK researchers report.

The team in Oxford said their studies closely resemble the treatments that would be needed in people with degenerative eye disease.

Similar results have already been achieved with night-blind mice.

Experts said the field was advancing rapidly, but there were still questions about the quality of vision restored.

Patients with retinitis pigmentosa gradually lose light-sensing cells from the retina and can become blind.

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It’s the first proof that you can take a completely blind mouse, put the cells in and reconstruct the entire light-sensitive layer”

Prof Robert MacLaren University of Oxford

The research team, at the University of Oxford, used mice with a complete lack of light-sensing photoreceptor cells in their retinas. The mice were unable to tell the difference between light and dark.

Reconstruction

They injected “precursor” cells which will develop into the building blocks of a retina once inside the eye. Two weeks after the injections a retina had formed, according to the findings presented in the Proceedings of the National Academy of Sciences journal.

Prof Robert MacLaren said: “We have recreated the whole structure, basically it’s the first proof that you can take a completely blind mouse, put the cells in and reconstruct the entire light-sensitive layer.”

Previous studies have achieved similar results with mice that had a partially degenerated retina. Prof MacLaren said this was like “restoring a whole computer screen rather than repairing individual pixels”.

The mice were tested to see if they fled being in a bright area, if their pupils constricted in response to light and had their brain scanned to see if visual information was being processed by the mind.

Vision

Prof Pete Coffee, from the Institute of Ophthalmology at University College London, said the findings were important as they looked at the “most clinically relevant and severe case” of blindness.

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This is probably what you would need to do to restore sight in a patient that has lost their vision”

Prof Pete Coffee University College London

“This is probably what you would need to do to restore sight in a patient that has lost their vision,” he said.

However, he said this and similar studies needed to show how good the recovered vision was as brain scans and tests of light sensitivity were not enough.

He said: “Can they tell the difference between a nasty animal and something to eat?”

Prof Robin Ali published research in the journal Nature showing that transplanting cells could restore vision in night-blind mice and then showed the same technique worked in a range of mice with degenerated retinas.

He said: “These papers demonstrate that it is possible to transplant photoreceptor cells into a range of mice even with a severe level of degeneration.

“I think it’s great that another group is showing the utility of photoreceptor transplantation.”

Researchers are already trialling human embryonic stem cells, at Moorfields Eye Hospital, in patients with Stargardt’s disease. Early results suggest the technique is safe but reliable results will take several years.

Retinal chips or bionic eyes are also being trialled in patients with retinitis pigmentosa.

Dr Thomas Challenger Challenger Mission