April 9, 2013
Doctors found that patients taking a certain class of drugs used to treat high blood pressure had less of the brain plaque characteristic of Alzheimer’s disease after they died. The findings suggest that the drugs, known as angiotensin receptor blockers, may help to protect the brain against Alzheimer’s, though more research is needed to determine whether they are effective in slowing the memory loss and other symptoms of the disease.
In addition to treating high blood pressure, the drugs, also known as “sartans,” are sometimes prescribed to help manage heart failure associated with diabetes-related kidney disease. They include such drugs as valsartan (brand name Angiotan or Diovan), losartan (Cozaar), irbesartan (Avapro), telmisartan (Micardis), candesartan (Atacand), olmesartan (Benicar) and eprosartan (Teveten).
In the study, published online in the Archives of Neurology, doctors examined the brains of 890 people who were being treated with various high blood pressure drugs, including sartans. Most were in their 70s or 80s when they died. Only some had Alzheimer’s disease.
The researchers found that on autopsy, those who were taking sartans had less plaque in their brains than those who were taking other high blood pressure drugs, regardless of whether they had Alzheimer’s disease or not. Buildup of plaque, composed of the toxic protein beta-amyloid, is a hallmark of Alzheimer’s, though some people with plaque buildup do not show signs of the disease. And whether the diminution of plaque buildup observed in this study in those taking sartans translates to fewer memory problems remains to be determined.
“It would have to be proved in a clinical trial if these effects observed in a study with autopsies are expressed in a clinic realm,” said the lead researcher, Dr. Ihab Hajjar of the University of Southern California’s Keck School of Medicine.
He noted that high blood pressure has been linked to an increase risk of Alzheimer’s and other forms of dementia. And other studies have suggested that angiotensin receptor blockers may have benefits for brain health.
A large study of American veterans with high blood pressure, for example, found that those taking the drugs had a lower risk of developing Alzheimer’s and other forms of dementia than those taking other high blood pressure drugs, including ACE inhibitors, another class of antihypertensives. Studies in animals also suggest that angiotensin receptor blockers may have effects that hinder the production of beta-amyloid.
Still, scientists do not know a lot about the effects of high blood pressure drugs on Alzheimer’s disease in people.
These autopsy findings offer some intriguing clues. Some earlier research has shown that high blood pressure drugs were associated with less plaque buildup, even compared to those who did not have high blood pressure. And this study showed that angiotensin receptor blockers, or sartans, may have more potency against beta-amyloid than other classes of hypertension drugs.
When treating high blood pressure, doctors have a wide range of drugs to choose from. Each class of drugs has unique benefits, and drawbacks. In the current study, for example, patients taking sartans were more likely to have had a stroke than those getting other types of drugs, which may have affected results. More study will be needed to confirm the findings and determine who might most benefit from taking sartans.
Source: Ihab Hajjar, MD, MS; Lauren Brown, BS, MPH; Wendy J. Mack, PhD; Helena Chui, MD: “Impact of Angiotensin Receptor Blockers on Alzheimer Disease Neuropathology in a Large Brain Autopsy Series .” Archives of Neurology Online, Sept. 2012.