A study published in the January 13, 2010 issue of the Journal of Neuroscience links a loss of smell function in Alzheimer's disease (AD) model animals with amyloid (protein) accumulation in the brain, a distinguishing hallmark of Alzheimer's disease. Research conducted by NYU Langone Medical Center suggests that olfactory dysfunction, a common symptom of AD, may serve as an early diagnostic tool for the disease.
The formation of amyloid plaques and neurofibrillary tangles are believed to contribute to the degradation of the neurons in the brain and the subsequent symptoms of AD. In this newly published study, NYU Langone scientists used genetically engineered mice, which developed amyloids in their brains, reflecting a progressive Alzheimer's disease pathology similar to humans. They found that Alzheimer's disease amyloid pathology occurs first in a region of the mouse brain responsible for smelling--which is directly above their noses. This pathology also coincided with the animals having abnormal abilities to smell. The mice with a high concentration of amyloid in their brains had to sniff odors longer to "learn" them than mice with less amyloid. They also had problems differentiating between odors.
As the article in the Journal of Neuroscience suggests, since the behavioral symptoms of AD often occur early in life, it is possible that this new olfactory method, looking at olfactory perception across multiple presentations of the same odor, may be advantageous in early detection of Alzheimer's -- prior to substantial degeneration of the brain.
"What was striking in our study, was that performance of the mouse in the olfactory behavior test was sensitive to even the smallest amount of amyloid presence in the brain as early as three months of age (equivalent to a young adult). This is a revealing finding because unlike a brain scan, a laboratory-designed olfactory test may be an inexpensive alternative to early diagnosis of Alzheimer's," noted co-author of the project, Daniel W. Wesson, PhD, of the NYU School of Medicine and the Nathan S. Kline Institute for Psychiatric Research in Orangeburg, New York. Presently, much scientific interest exists in establishing methods to diagnose Alzheimer's prior to the irreversible deterioration of the brain characteristic of the disease.
"These novel results provide a two-fold benefit, not only in confirming that olfactory problems may serve as an early indicator of Alzheimer's, but that further validation in humans could facilitate testing of new therapies for the disease," remarked study co-author Ralph A. Nixon, MD, PhD, Director of the Center of Excellence on Brain Aging at NYU Langone Medical Center and professor in the Departments of Psychiatry and Cell Biology.
The study was also co-authored by Donald A. Wilson, PhD, professor in the Department of Child and Adolescent Psychiatry and Efrat Levy, PhD, associate professor in the Departments of Psychiatry and Pharmacology at NYU Langone Medical Center. All researchers are affiliated with the Center of Excellence on Brain Aging at NYU Langone and the Nathan S. Kline Institute for Psychiatric Research, a facility of the New York State Office of Mental Health.
Funding for the study was provided by grants from the National Institutes of Health in Bethesda, Maryland and the Alzheimer's Association.
About the Center of Excellence on Brain Aging
The Center of Excellence (COE) on Brain Aging is devoted to research and clinical advances toward the treatment and cure of all neurodegenerative diseases affecting cognition, with expertise in healthy brain aging, Alzheimer's disease and memory disorders, Parkinson's disease and movement disorders, atypical dementias, and geriatric psychiatry. Clinical care is conducted through two outpatient facilities: The Pearl Barlow Center for Memory Evaluation and Treatment; and The NYU Parkinson and Movement Disorders Center. The Barlow Center focuses on Alzheimer's disease and memory disorders and includes specialty sub-clinics-- one devoted to Non-Alzheimer's disease dementias and Prion diseases, and another specializing in Normal Pressure Hydrocephalus, the only one of its kind in NYC. The COE was founded upon the strengths of NYU Langone's existing Silberstein Alzheimer's Institute, which for decades has been devoted to the understanding, cure and prevention of age-related cognitive decline through research, public education, and evidence-based clinical care." For more information: http://aging.
About NYU Langone Medical Center
NYU Langone Medical Center is one of the nation's premier centers of excellence in healthcare, biomedical research, and medical education. For over 168 years, NYU physicians and researchers have made countless contributions to the practice and science of health care. Today the Medical Center consists of NYU School of Medicine, including the Smilow Research Center, the Skirball Institute of Biomolecular Medicine, and the Sackler Institute of Graduate Biomedical Sciences; the three hospitals of NYU Hospitals Center, Tisch Hospital, a 705-bed acute-care general hospital, Rusk Institute of Rehabilitation Medicine, the first and largest facility of its kind, and NYU Hospital for Joint Diseases, a leader in musculoskeletal care; and such major programs as the NYU Cancer Institute, the NYU Child Study Center, and the Hassenfeld Children's Center for Cancer and Blood Disorders.