TUESDAY, Sept. 11 (HealthDay News) -- Angiotensin receptor blockers, drugs commonly taken to control high blood pressure, appear to reduce the amount of plaque in the brains of Alzheimer's patients and others, a new study shows.

These results were found when patients with high blood pressure on drugs such as losartan (Cozaar) died and underwent an autopsy. These brain plaques are a hallmark of Alzheimer's disease. Whether, however, these drug also improve mental function isn't known, the researchers added.

"[It] would have to be proven in a clinical trial whether these effects seen in an autopsy study manifest themselves in a clinical setting," said lead researcher Dr. Ihab Hajjar, an assistant professor at the University of Southern California Keck School of Medicine. "But since we don't have any treatment for Alzheimer's, it's worth pursuing."

Candesartan (Atacand), irbesartan (Avapro), olmesartan (Benicar), valsartan (Diovan), telmisartan (Micardis) and eprosartan (Teveten) are other angiotensin receptor blockers approved by the U.S. Food and Drug Administration.

Although this study can't determine whether angiotensin receptor blockers improve mental function in Alzheimer's patients, Hajjar pointed out there is a connection between blood pressure and brain health, and the choice of blood-pressure lowering drugs may make a difference in maintaining brain function.

The report was published online in the Sept. 10 issue of the Archives of Neurology.

For the study, Hajjar's team autopsied the brains of 890 patients with hypertension who had been taking various medications to lower their blood pressure. Some of these patients had Alzheimer's disease while others didn't. Some had been diagnosed with dementia but not Alzheimer's. Most were in their 70s or 80s when they died.

Patients taking angiotensin receptor blockers had fewer brain plaques whether or not they had been diagnosed with Alzheimer's, the researchers found.

Moreover, these results were seen only among those who had been taking angiotensin receptor blockers and not among patients taking any other blood pressure medications.

Patients treated with angiotensin receptor blockers had fewer brain plaques than people not treated with any blood pressure drug, the study also found.

"Uncontrolled hypertension is a recognized risk for Alzheimer's disease and for vascular dementia, so this is unsurprising, but highly welcome, news," said Dr. Sam Gandy, the Mount Sinai chair in Alzheimer's Disease Research and associate director of the Mount Sinai Alzheimer's Disease Research Center, in New York City.

Hajjar's team is looking at the effects of this group of drugs in people who Alzheimer's or other forms of dementia. A pilot study found they did slow or prevent decline in areas of the brain that are susceptible to damage from high blood pressure.

While the new study found an association between these blood pressure medicines and levels of brain plaque, it did not prove a cause-and-effect relationship.

More information

For more about Alzheimer's Disease, visit the Alzheimer's Association  .

SATURDAY Sept. 1 (HealthDay News) -- It's safe for older adults to run marathons, a new study finds.

Researchers at the University of Manitoba in Canada tested marathon participants over age 50 before and after their 26.2-mile run. Using blood tests, ultrasounds and scans up to three months later, they found the runners had temporary heart effects similar to those seen in runners aged 18 to 40.

The effects included a brief increase in blood indicators of heart damage and temporary swelling and weakness in the right side of the heart immediately after the marathon. All of these effects disappeared within a week.

"There was no evidence of permanent heart damage from repeated marathon running in individuals over the age of 50," primary study author Davinder Jassal, an associate professor of medicine, radiology and physiology, said in a university news release.

The study was published online in August in the Journal of Cardiovascular Magnetic Resonance.

Aging populations in Canada and the United States mean there's a growing number of people over age 50 who exercise regularly, the researchers noted. For example, the number of older people taking part in marathons has doubled over the past two decades.

More information

The U.S. National Heart, Lung, and Blood Institute offers a guide to physical activity.

MONDAY, Aug. 13 (HealthDay News) -- A new study finds that two antibiotics commonly used to treat respiratory and sinus infections -- moxifloxacin (Avelox) and levofloxacin (Levaquin) -- may boost the risk of severe liver injury in seniors.

The two drugs belong to a class of antibiotics called fluoroquinolones.

For the study, published Aug. 13 in CMAJ (the Canadian Medical Association Journal), Canadian researchers examined the medical records of 144 patients in Ontario who were over 65 and admitted to the hospital to treat liver injury within a month of receiving moxifloxacin or other antibiotics commonly used to treat respiratory infections. The patients had no history of liver disease, and 88 of them died.

"Compared with clarithromycin, moxifloxacin was associated with a more than twofold increased risk of admission to hospital for acute liver injury," the study authors wrote in a journal news release. "Levofloxacin was also associated with a statistically significant but lower risk of hepatotoxicity than moxifloxacin."

However, the risk of liver injury is rare, say the researchers, from Toronto's Institute for Clinical Evaluative Sciences, the University of Toronto and McMaster University in Hamilton, Ontario. Liver problems affect about six of each 100,000 patients treated with the antibiotics, they found.

"Despite recent regulatory warnings regarding the hepatic safety of moxifloxacin, there is a lack of controlled studies supporting the notion that moxifloxacin presents a particular risk relative to other broad-spectrum antibiotic agents and, in particular, to other fluoroquinolones," the authors said. "Although our results require confirmation in other settings, the findings suggest that both moxifloxacin and levofloxacin be considered for regulatory warnings regarding acute liver injury."

While the study found an association between use of these antibiotics and liver injury, it does not show a cause-and-effect relationship.

More information

For more about liver disease, see the U.S. National Library of Medicine.