jueves, 11 de abril de 2013

Blood Pressure Drugs May Help Slow Alzheimer’s

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.

By ALZinfo.org, The Alzheimer's Information Site. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer's Research Foundation at The Rockefeller University.

Three Drugs to Be Tested to Prevent Alzheimer’s

Scientists have chosen three drugs to be tested as a way to prevent the onset of Alzheimer’s disease in people who are genetically predisposed to get the disease at an early age. If one or more of the medications prove to be effective, the hope is that they may also provide benefits for the millions more people at high risk of developing the far more common late-onset form of Alzheimer’s.

Current Alzheimer’s medications may ease symptoms for a time but do not stem the underlying progression of disease or prevent its onset. These new drugs, under investigation, are targeted at preventing the memory loss and thinking problems of Alzheimer’s from occurring in the first place. The study will be conducted at medical centers in the U.S., Europe and Australia starting in 2013.

“Trying to prevent Alzheimer’s symptoms from ever occurring is a new strategy,” says Dr. John C. Morris, a professor at Washington University School of Medicine, which is leading the study.

The study will test the drugs in 160 volunteers who have one of several genes that cause early-onset Alzheimer’s. People who inherit such genes typically begin to show signs of dementia at an early age, typically younger than 50. Carrying such genes leads to Alzheimer’s in 100 percent of cases, unlike the APOE gene that can raise the risk of late-onset Alzheimer’s but does not guarantee you will get the disease.

The three drugs undergoing testing are designed to combat the toxic effects of beta-amyloid, the toxic protein that builds up and forms plaques in the brains of those with Alzheimer’s. Each works in different ways. The drugs are:

*Gantenerumab, an antibody that attaches to beta-amyloid and helps to remove it from the brain.

*Solanezumab, which binds to beta-amyloid before it clumps together, inhibits  the plaque formation process.

* LY2886721, a drug that blocks an enzyme, beta-secretase, which is critical for beta-amyloid formation, thereby reducing the amount of beta-amyloid produced in the first place.

Earlier studies have shown them to be generally safe, with some hints that they may have benefits against Alzheimer’s. A recent analysis of data on solanezumab, for example, found that while the drug did not meet the study’s goals, it might slow memory loss in those with very mild Alzheimer’s.

For the prevention study, participants will be started on one of the three drugs, or a placebo, years before signs of memory loss or thought problems have appeared. At this early stage, the effects of the disease process on the brain are likely to be minimal. The hope is that by starting early, before brain damage has taken root, the drugs may stave off future development of symptoms. Eighty volunteers who do not have the genes will also participate as controls.

“In most trials in Alzheimer’s disease, people are treating the disease after the damage is being done to the brain,” said study leader Dr. Randall Bateman of Washington University. “And in this trial we’re trying to treat the disease before that damage gets done.”

Participants will receive scans and tests to look for signs of brain plaques and levels of beta-amyloid in the blood and spinal fluid. Such markers are an indication that Alzheimer’s disease is progressing, even if symptoms like memory loss are not evident. Scientists will monitor these markers to see whether the new treatments may be working to slow to stop the disease.

The first part of the trial, being conducted by a research partnership known as the Dominantly Inherited Alzheimer’s Network, or DIAN, is expected to last for two years. If it appears one or more of the drugs are working, volunteers will be switched to those drugs, and the trial will likely be expanded. For more information, visit www.Dian-Info.org.

By ALZinfo.org, The Alzheimer's Information Site. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer's Research Foundation at The Rockefeller University.

How Meditation May Help Against Alzheimer’s

Meditation is commonly used to reduce stress and provide a sense of well-being. Now researchers are finding that meditation may be indirectly useful against Alzheimer’s disease as well. Studies from the University of California, Los Angeles, found that teaching people to do meditation reduced stress among those who cared for someone with Alzheimer’s. Meditation also made seniors feel less lonely and isolated, which has been linked to an increased risk of developing the disease.

In one study, UCLA researchers followed-up on earlier findings showing that meditation eased stress levels in those who cared for a loved one with Alzheimer’s or another form of dementia, and looked for physical changes indicating improved health.

“We know that chronic stress places caregivers at a higher risk for developing depression,” said Dr. Helen Lavretsky, senior author and a professor of psychiatry at UCLA. “On average, the incidence and prevalence of clinical depression in family dementia caregivers approaches 50 percent. Caregivers are also twice as likely to report high levels of emotional distress,” and many are at increased risk of heart disease and other life-threatening ailments.

She and her team recruited 45 men and women who were caring for a family member with dementia. The caregivers were divided into two groups. One group was taught a brief, 12-minute yoga practice called Kirtan Kriya that included an ancient chanting meditation, which was performed every day at the same time for eight weeks. The other group was asked to relax in a quiet place with their eyes closed while listening to music on a relaxation CD, also for 12 minutes daily for eight weeks. Blood samples were taken at the beginning of the study and again at the end of the study.

After eight weeks of daily chanting, the meditation group showed clear reductions in levels of various proteins linked to inflammation. Increasingly, inflammation is recognized as a contributor to the development of heart disease and other chronic illnesses, including Alzheimer’s disease.

“This is encouraging news,” Dr. Lavretsky said. “Caregivers often don’t have the time, energy or contacts that could bring them a little relief from the stress of taking care of a loved one with dementia, so practicing a brief form of yogic meditation, which is easy to learn, is a useful tool.” The findings were published online in the journal Psychoneuroendocrinology.

For the second study, which appeared in the journal Brain, Behavior and Immunity, researchers looked at 40 older adults ranging in age from 55 to 85. Half were taught mindfulness meditation, a type of Buddhist meditation that promotes being mindful of the present moment and letting go off worries relating to the past or future. The meditators attended weekly two-hour meetings in which they learned the techniques of mindfulness, including awareness and breathing techniques. They also practiced mindfulness meditation for 30 minutes each day at home and attended a single, daylong retreat. The other half did not meditate.

The researchers found that practicing mindfulness meditation reduced feelings of loneliness in seniors. Many elderly people are prone to loneliness, which has been linked to poor health and an increased risk of heart disease, depression and Alzheimer’s.

Meditation also reduced levels of inflammatory proteins. “Our work presents the first evidence showing that a psychological intervention that decreases loneliness also reduces” markers for inflammation, said Dr. Steve Cole, professor of medicine at UCLA. “If this is borne out by further research, mindfulness-based stress reduction could be a valuable tool to improve the quality of life for many elderly people,” including those caring for a loved one with Alzheimer’s disease.

The results “add to a growing body of research that is showing the positive benefits of a variety of meditative techniques, including tai chi and yoga,” said Dr. Michael Irwin, a study author and professor of psychiatry at UCLA. “These studies begin to move us beyond simply connecting the mind and genome, and identify simple practices that an individual can harness to improve human health.”

By ALZinfo.org, The Alzheimer's Information Site. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer's Research Foundation at The Rockefeller University