Australia - Regular Aspirin Use Linked To Age-Related Eye Disease Risk

Regular aspirin consumption may be associated with an increased risk of neovascular age-related macular degeneration, says a new study.

Researchers in Australia have found that regular aspirin consumption is associated with an increased risk of neovascular age-related macular degeneration (AMD) – a leading cause of blindness in older people.

The research, carried out at the Center for Vision Research from the Westmead Millennium Institute for Medical Research (WMI), shows that the risk appears to be independent of a history of smoking, which is also a known preventable risk factor for AMD.

Aspirin is one of the most widely used medications in the world with more than 100 billion tablets consumed each year. It is commonly used in the prevention of cardiovascular disease, such as myocardial infarction (heart attack) and ischemic stroke.

While a five-year European study published last year suggested that regular aspirin use (defined as once or more per week in the past year) was associated with AMD, other studies had reported inconsistent findings.

The study, carried out by the Center for Vision Research’s Dr. Gerald Liew and colleagues, was conducted over a much longer period and found clear evidence of the risk.

They conducted a prospective analysis of data from an Australian study (the Blue Mountains Eye Study) that included four examinations during a 15-year period.

Of 2,389 participants, 257 individuals (10.8 percent) were regular aspirin users. After the 15-year follow-up, 63 individuals from the 2,389 participants developed incident neovascular AMD, according to the results.

“The cumulative incidence of neovascular AMD among nonregular aspirin users was 0.8 percent at five years, 1.6 percent at 10 years, and 3.7 percent at 15 years,” said the director of WMI’s Center for Vision Research, Professor Paul Mitchell.

“Among regular aspirin users, the cumulative incidence was 1.9 percent at five years, 7 percent at 10 years and 9.3 percent at 15 years, respectively, indicating that regular aspirin use is significantly associated with an increased incidence of neovascular AMD. This increase was around 2.5-fold, after accounting for potentially confounding variables.”

The report’s authors note that any decision concerning whether to stop aspirin therapy is “complex and needs to be individualized.” Further confirmation of these findings will also be important.

“Currently, there is insufficient evidence to recommend changing clinical practice, except perhaps in patients with strong risk factors for neovascular AMD (such as existing late AMD in the fellow eye) in whom it may be appropriate to raise the potentially small risk of incident neovascular AMD with long-term aspirin therapy,” the authors conclude.

Source: University of Sydney.

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Canada - Researchers find potential for new uses of old drug

Researchers in Canada, Scotland and Australia have discovered that salicylate, the active ingredient in aspirin, directly increases the activity of the protein AMPK (AMP-activated protein kinase), a key player in regulating cell growth and metabolism.

AMPK which is considered a cellular fuel-gauge is switched on by exercise and the commonly used anti-diabetic medication metformin.

The research from scientists at McMaster University, the University of Dundee and the University of Melbourne will be published in today's issue of the journal Science.

"We're finding this old dog of aspirin already knows new tricks," said Dr. Greg Steinberg, a co-principal investigator of the study. "In the current paper we show that, in contrast to exercise or metformin which increase AMPK activity by altering the cells energy balance, the effects of salicylate is totally reliant on a single Ser108 amino acid of the beta 1 subunit.

"We show that salicylate increases fat burning and reduces liver fat in obese mice and that this does not occur in genetically modified mice lacking the beta1 subunit of AMPK," he said. Steinberg is an associate professor of medicine in the Michael G. DeGroote School of Medicine at McMaster University and the Canada Research Chair in Metabolism and Obesity.

These findings are important as a large clinical trial is currently underway testing whether salsalate (a well-tolerated aspirin derivative), can preventType 2 diabetes.

Salicylate, which is derived from willow bark, and is the active ingredient in aspirin, is believed to be one of the oldest drugs in the world with first reports of its use dating back to an Egyptian papyrus in 1543 BC.

An anti-inflammatory drug first used as a painkiller more than a century ago, aspirin is now given to people at risk of heart attacks and strokes as well as patients with vascular disease. McMaster scientists played a key role in that previous research.

Three studies published last month in the medical journal The Lancet reported that taking an aspirin every day may significantly reduce the risk of many cancers and prevent tumors from spreading. The unanswered question was how this anti-cancer benefit occurs.

With many recent studies showing that metformin may be important for cancer prevention the authors' study raise the interesting possibility that aspirin may also be working in a similar manner; however, further studies are needed as the concentrations of salicylate used in the current study were higher than the cancer trials. Nonetheless, the researchers' results show the one thing that salicylates and metformin hold in common is their ability to activate AMPK.

Provided by McMaster University (news : web)

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