Little Evidence That Diet, Lifestyle Cuts Alzheimer's Risk

Numerous studies have attempted to link specific behaviors and health conditions to the onset of Alzheimer's disease, but scientists still can't say for sure that anything you do or don't do will prevent the brain disorder, according to a new U.S. review of recent research. The U.S. National Institutes of Health convened a conference last spring to analyze 18 studies of potential risk factors, such as poor eating habits, chronic illness, smoking or little exercise, and development of Alzheimer's disease. "Although we are not dismissing the potential or important role that these major risk factors might play in the development of Alzheimer's disease, at this time, with what we have currently, we cannot confirm any risk associations," said study lead author Dr. Martha L. Daviglus, a professor of preventive medicine and medicine at the Northwestern University Feinberg School of Medicine in Chicago.

"So we need to conduct more research, if we want to have the evidence in hand," she added. The study, which summarizes the NIH conference results, is published in the May 9 online edition and September print issue of the Archives of Neurology. For now, older age is the leading known risk factor for Alzheimer's disease, the study noted. A gene variation is also tied to increased risk, it said. An estimated 5.3 million Americans struggle with Alzheimer's, a figure projected to grow as the country's Baby Boomer population ages, the authors said. The disease is responsible for between 60 and 80 percent of dementia cases. "What we're talking about here is something that is going to affect so many Americans in the years to come," said one expert, Catherine Roe, an instructor in neurology at Washington University School of Medicine in St. Louis. "In fact, there's going to be an explosion in the next 50 years, because everyone is living longer in general," she said.

The studies included in the NIH research review were conducted between 1984 and 2009 in English. Participants were at least 50 years old and living in developed countries. Some of the studies looked into dietary influences, such as folic acid intake, Mediterranean diet and nutritional supplements. Others looked for a link between health problems, such as diabetes or high cholesterol, and Alzheimer's. Still others explored levels of physical activity or alcohol consumption and risk of Alzheimer's disease. The NIH team found that, as a whole, the studies were "compromised by methodological limitations" that undercut the ability to draw a firm association between any particular behavioral habit and/or health condition and Alzheimer's.

Genome Scans May Reveal Life-Saving Alternatives for Cancer Patients

A 39-year-old woman is referred to Washington University's Siteman Cancer Center in St. Louis with suspected acute myeloid leukemia (AML), a cancer that can be treated relatively simply with medication, or not so simply with a high-risk stem cell transplant, depending on the tumor subtype. But finding out which type of cancer she has proves trickier than expected. While the pathologist sees a type of leukemia known as M3AML, which generally has a good outcome and can be treated with the drug ATRA, the cytogeneticist sees something entirely different.

In his analysis, the woman has a type of leukemia with poor long-term survival that is usually treated with stem cell transplantation a risky therapy that sometimes leads to death. Fortunately, in this case study, documented in the April 20 issue of the Journal of the American Medical Association, the woman's oncologist is aware of a clinical trial and, deferring treatment for six weeks, refers her there so the researchers can do a full scan of her genome and come up with an answer.

Full-genome sequencing involves scanning all the thousand of genes on the human genome to try to find a mistake. It's different from the more common gene testing these days, which looks only for specific DNA that might or might not be responsible for a particular problem. In the St. Louis case, the more in-depth sequencing, done in only seven weeks, uncovered a new genetic "mistake" that showed the woman could be treated with ATRA and not the more-complicated, risky stem cell transplantation.

Gene Activity May Affect Acute Myeloid Leukemia Outcome

For acute myeloid leukemia patients, overactive genes in their leukemic stem cells (LSC) can translate into a more difficult struggle to overcome their disease and achieve prolonged remission, new research reveals. "In many cancers, specific subpopulations of cells appear to be uniquely capable of initiating and maintaining tumors," the study authors explained in their report. The researchers identified 52 LSC genes that, when highly active, appear to prompt worse outcomes among acute myeloid leukemia (AML) patients.

Between 2005 and 2007, study author Andrew J. Gentles, of Stanford University in Palo Alto, Calif., and colleagues examined gene activity in a group of AML patients as well as healthy individuals. Separate data concerning AML tumors in four groups of patients (totaling more than 1,000) was also analyzed. In one of the patient groups, the investigators found that higher activity levels among 52 LSC genes meant a 78 percent risk of death within a three-year period. This compared with a 57 percent risk of death in the same time frame for AML patients with lower gene activity among these specific "signature" genes.

In another AML patient group, the research team observed that higher gene activity prompted an 81 percent risk for experiencing a disease set-back over three years, compared with just a 48 percent risk among patients with low gene activity. What's more, Gentles and his colleagues found that higher activity among these 52 LSC genes generally meant a poorer response to chemotherapy treatment and lower remission rates.

Docs Claim Transplant Cured Man of HIV, But Experts Urge Caution

In a rare case, a man living in Germany who had both leukemia and AIDS no longer has any detectable HIV cells in his blood following a stem cell transplant for his leukemia three years ago. But experts were quick to caution that the case does not have practical implications for the treatment of AIDS worldwide. As it turns out, the donor for that transplant carried a rare mutation in a gene that increases immunity against the most common form of HIV.

First reported in 2009, this follow-up study, published online in the journal Blood, confirms that the recipient patient is still free of both leukemia and HIV three years after the transplant. But one expert issued strong words of caution in interpreting the finding. "Our phones have been ringing off the hook," said Dr. Margaret Fischl, director of the AIDS clinical research unit at the University of Miami Miller School of Medicine. "We are having patients calling us and asking if they can stop their antiretroviral therapy and the answer is uncategorically no."

The theory is that if you could wipe out every infected cell you could cure HIV, Fischl said, but this is a unique case. The patient had intense chemotherapy and radiation, then relapsed and was given a second transplant from the same donor. The donor was unique in that he had a gene that could fight the most common form of HIV. This mutation is seen in about one in every million people, Fischl explained.

Gene Therapy Shows Potential Against Heart Failure

By substituting a healthy gene for a defective one, scientists were able to partially restore the heart's ability to pump in 39 heart failure patients, researchers report. "This is the first time gene therapy has been tested and shown to improve outcomes for patients with advanced heart failure," study lead author Dr. Donna Mancini, professor of medicine and the Sudhir Choudhrie professor of cardiology at Columbia University College of Physicians and Surgeons in New York City, said in a university news release.

"The therapy works by replenishing levels of an enzyme necessary for the heart to pump more efficiently by introducing the gene for SERCA2a, which is depressed in these patients. If these results are confirmed in future trials, this approach could be an alternative to heart transplant for patients without any other options," she added. Mancini presented the results Monday at the annual meeting of the American Heart Association (AHA) in Chicago. The gene for SERCA2a raises levels of the enzyme back to where the heart can pump more efficiently. The enzyme regulates calcium cycling, which, in turn, is involved in how well the heart contracts, the researchers said.

"Heart failure is a defect in contractility related to calcium cycling," explained Dr. Robert Eckel, past president of the AHA and professor of medicine at the University of Colorado Denver. The study authors hope that, if replicated in larger trials, the gene therapy treatment could actually delay or obviate the need for heart transplants in patients with heart failure. "There are a lot of treatments for heart failure but at some point patients stop responding and then the prognosis is poor," said Dr. Rita Redberg, AHA spokeswoman and professor of medicine at the University of California, San Francisco. After that, the only option is a transplant.

Research Sheds Light on Why Autism Is More Prevalent in Boys

A new study is helping unravel an enduring mystery surrounding autism: Why boys are much more likely to be affected by the disorder than girls. An international team led by Dr. John Vincent, of the Centre for Addiction and Mental Health in Toronto, examined specific genes in almost 3,000 people with an autism spectrum disorder (ASD) and 246 others with intellectual disability. They then compared that data to genes from more than 10,000 control individuals. Reporting in the Sept. 15 issue of Science Translational Medicine, the team found that mutations in the PTCHD1 gene are linked to inherited forms of autism and intellectual disability in about 1 percent of affected people in the study. It was not found in any of the controls, however. "Our data indicate that mutations at the PTCHD1 locus are strongly associated with ASD," the researchers concluded. They also noted that this gene is typically located on the single X-chromosome in males.

The study "provides further clues as to why ASD affects four times more males than females," said Andy Shih, vice president for scientific affairs at Autism Speaks. "PTCHD1 is part of a neurobiological pathway that determines the development of human embryos. It is one of several genes recently implicated in both ASD and intellectual disabilities." The finding adds a little more clarity to the murky origins of autism, Shih said. While each new genetic discovery "may only account for a small fraction of the cases, collectively they are starting to account for a greater percentage of individuals in the autism community, as well as providing insights into possible common pathogenic mechanisms," he said. "Identification of a male-linked genetic mutation begins to address the previously unknown basis for often reported skewed male-to-female ratio in autism."