Pet Scans Can Monitor Fatty Acid Metabolism Diseases And Their Devastating Effects On The Heart

The Columbia-Presbyterian Medical Center Division of Cardiology is doing unique research to detect and follow the progression of these disorders

NEW YORK, Nov. 30, 2001 – PET scanning can improve the diagnosis and characterization of fatty acid metabolism diseases, conditions which, if untreated, can lead to severe heart problems and sudden death in affected children, according to results from a study by researchers at Columbia University College of Physicians & Surgeons. In the study, led by Dr. Steven R. Bergmann, professor of medicine and radiology at the medical school and director of nuclear cardiology at Columbia Presbyterian Medical Center of NewYork-Presbyterian Hospital, the researchers found that positron emission tomography, or PET scanning, can non-invasively assess abnormal patterns of energy metabolism in the hearts of young patients affected by fatty acid metabolism disorders. Fatty acid metabolism disorders encompass a variety of rare inherited disorders in which sufferers cannot break down or transport certain fatty acids to make energy in the heart. Although the heart can use the sugar glucose after meals to derive energy for its continuous pumping activity, in between meals the heart shifts to other fuels, primarily fatty acids. Without the proper energy, the heart could potentially stop. Dr. Bergmann believes that some children in the United States who die suddenly may actually have these fatty acid metabolism disorders that are undiagnosed. It remains unknown how prevalent these diseases are. While some affected children will outgrow the condition, others will need care for the rest of their lives to prevent them from having a metabolic crisis. Such children are fed with feeding tubes and have to be awakened while they sleep or have a parent administer necessary medication or supplementation throughout the night. The children also suffer skeletal muscle problems and liver failure, if untreated. PET allows imaging of internal body tissues by using short-lived positron-emitting isotopes. Chemists incorporate the isotopes, manufactured by an on-site cyclotron, into compounds of interest to the researcher. In this study, palmitate, a long-chain fatty acid, was labeled and injected into participants for imaging and blood flow evaluations inside the heart. While other tests, such as genetic or enzyme assays, diagnose fatty acid metabolism disorders, they cannot always characterize the severity of the disease and cannot provide direct information about the degree of cardiac involvement. The aim of the Columbia study was to use PET to understand the severity of the diseases and their impact on the heart. In the study, the researchers were able to monitor blood flow in the heart, overall energy use in the heart, the percentage of fatty acid use relative to total energy use, and heart function in 11 patients and six unaffected siblings. The investigators found that affected children have a diminished capacity to use fatty acids compared with their siblings and that affected children’s fatty acids are deposited in a non-energy producing pathway, storing them as fat. Researchers are still enrolling patients to try to determine the prevalence of these disorders and to do follow-up analyses. “We hope to continue these studies to be able to follow the natural history of the disease and when new treatments, such as gene therapy, become available, we will then be able to monitor improvement in the patients over time,” Dr. Bergmann says. “We are the only facility, as far as I know, that can do this type of study because of our PET and cyclotron technology and our cardiac expertise.” The results of the research are being published in the December issue of the Journal of Inherited Metabolic Diseases.

· The researchers are continuing to recruit more patients, children age 1 and older with diagnosed fatty acid metabolism disorders, into their study. The study is funded in part by a grant from the Department of Energy. The study also includes children with inherited or idiopathic (when no known cause can be found) cardiomyopathy, a disease in which the heart muscle becomes inflamed and functions poorly.

· Ronald McDonald House, a charity that provides housing for families and children needing hospital evaluations, and Angel Flight, an organization that provides transportation to medical care for sick children, helped families who live outside the New York City area bring their children to Columbia-Presbyterian Medical Center to be evaluated.

· The study was performed at the Morton A. Kreitchman PET Center, a clinical and research imaging facility housed at the Columbia-Presbyterian Medical Center, which comprises the Columbia University College of Physicians & Surgeons and NewYork-Presbyterian Hospital.

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