Enzyme could help fight against mid-life obesity and fitness loss

National Institutes of Health discovery of enzyme in mice could lead to new class of medications to fight mid-life obesity

A team of scientists led by researchers from the National Institutes of Health has identified an enzyme that could help in the continuous battle against mid-life obesity and fitness loss. The discovery in mice could upend current notions about why people gain weight as they age, and could one day lead to more effective weight-loss medications.

“Our society attributes the weight gain and lack of exercise at mid-life (approximately 30-60 years) primarily to poor lifestyle choices and lack of will power, but this study shows that there is a genetic program driven by an overactive enzyme that promotes weight gain and loss of exercise capacity at mid-life,” said lead study author Jay H. Chung, Ph.D., M.D., head of the Laboratory of Obesity and Aging Research at the National Heart, Lung, and Blood Institute (NHLBI), part of NIH.

Chung and his team used mice to test the potentially key role this enzyme plays in obesity and exercise capacity. They administered an inhibitor that blocked the enzyme in one group being fed high-fat foods, but withheld it in another. The result was a 40 percent decrease in weight gain in the group that received the inhibitor.

The study, the first to link the increased activity of this enzyme to aging and obesity, appears in the current issue of Cell Metabolism. Its findings could have ramifications for several chronic illnesses. With lower rates of obesity, the researchers say, rates of heart disease, diabetes, and other diseases that tend to increase with age, including cancer and Alzheimer’s disease, could fall as well.

Researchers have known for years that losing weight and maintaining the capacity to exercise tend to get harder beginning between ages 30 to 40 — the start of midlife. Scientists have developed new therapies for obesity, including fat-fighting pills. However, many of those therapies have failed because of a lack of understanding about the biological changes that cause middle-aged people to gain weight, particularly around their abdomen.

Click here to read the rest of this article originally published by National Institutes of Health

Study ties blood protein ApoE to Alzheimer’s brain abnormalities

In NIH-supported Alzheimer’s study, blood test in symptom-free volunteers links levels of specific protein with beta amyloid deposits

Scientists are seeking ways to detect the earliest stages of Alzheimer’s disease, since harmful changes may be taking place in the brain years before symptoms appear. Now, researchers report that a blood test detecting a specific protein in blood samples from cognitively normal older people may reflect the levels of beta-amyloid protein in the brain — a hallmark of the disease. Supported in part by the National Institutes of Health, the findings may eventually lead to a blood test that helps predict risk for Alzheimer’s disease and who may be a good candidate for participating in clinical trials.

Madhav Thambisetty, M.D., Ph.D., of the Intramural Research Program at the National Institute on Aging (NIA), part of the NIH, was the lead author on the study with collaborators from the Institute of Psychiatry at King’s College, London, and the Department of Radiology at Johns Hopkins University, Baltimore. The study appears in the Dec. 20, 2010, issue of the Journal of Alzheimer’s Disease.

“Recent advances in imaging and biomarkers that help track the onset and progression of Alzheimer’s disease show promise for early detection of the disease process, and for tracking the effectiveness of early interventions,” said NIA Director Richard J. Hodes, M.D. “This is critically important in streamlining and conducting trials more efficiently so that we can find out about possible therapies that much sooner.”

Using proteomics technology, a method of studying hundreds of proteins from a small blood sample, the researchers analyzed blood samples of 57 older and symptom-free volunteers to determine whether specific proteins were associated with amyloid burden in the brain. They measured brain amyloid using PET (positron emission tomography) scans with Pittsburgh Compound B, a tracer that binds to amyloid plaques. The volunteers are participating in the NIA’s Baltimore Longitudinal Study of Aging (BLSA), America’s longest-running scientific study of human aging.

The researchers found the amount of a specific protein called apolipoprotein E, or ApoE, in the blood samples was strongly associated with the level of beta amyloid in the brain. Those with high blood levels of the protein had significantly greater deposits of amyloid in the medial temporal lobe, the region of the brain important to memory function.

“These results are especially intriguing as this protein is made by the APOE gene, the most robust genetic risk factor for late-onset Alzheimer’s,” Thambisetty said. Late-onset Alzheimer’s is the most common form of the disease and occurs around age 65 or later.

He now plans to test these findings in serial blood samples collected every year in BLSA volunteers to determine how changing blood levels of ApoE protein may relate to pathological changes in the brain over time.

“If the results are equally positive, we may be able to develop a blood test that provides a less invasive, inexpensive method that helps to detect the early pathological changes of Alzheimer’s disease,” he said.

The NIA leads the federal government effort conducting and supporting research on aging and the health and well being of older people. For more on health and on aging generally, go to www.nia.nih.gov. The NIA provides information on age-related cognitive change and neurodegenerative disease specifically at its Alzheimer’s Disease Education and Referral (ADEAR) Center at www.nia.nih.gov/Alzheimers. To sign up for e-mail alerts about new findings or publications, please visit either website. To learn more about the BLSA, go to http://www.grc.nia.nih.gov/branches/blsa/blsanew.htm.

ALZHEIMER’s QUIZ

Alzheimer’s quiz: Diagnostic clues

Many people fret needlessly when they misplace their reading glasses or car keys — worried that this forgetfulness might be an early sign of Alzheimer’s disease.

While this type of memory loss is not related to Alzheimer’s, there are definite clues that doctors look for when diagnosing this disease.

Take our quiz to see if you can separate fact from fiction about diagnosing Alzheimer’s disease.

 http://www.mayoclinic.com/health/alzheimers/QZ00017