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EMBARGOED FOR RELEASE ON APRIL 18
NEW ORLEANS (April 18, 2005) An estimated 4.5 million Americans have Alzheimer's disease, and this figure may increase to as many as 16 million by the year 2050. While there is currently no cure, finding a treatment that could delay the onset or progression of Alzheimer's disease may prolong the life of those with the disease and perhaps eventually decrease the number of individuals affected. The proliferation of beta-amyloid plaque is considered a key factor in the development of Alzheimer's disease. Beta-amyloid protein accumulates in the brains of patients with Alzheimer's disease, activating immune cells that try unsuccessfully to remove it. That triggers the release of poisons that eventually kill nerve cells, leaving behind a trail of plaques and tangles the remains of nerve cells and fibers, clogged up with beta-amyloid.
Neurosurgeons recently conducted studies to determine whether the intraventricular injection of anti-beta-amyloid would inhibit the development of amyloid plaques without producing inflammation or hemorrhage. The study, Intraventricular Passive Immunization against ß-Amyloid as a Treatment for Alzheimer's Disease in Transgenic Mice, will be presented by Terry Lichtor, MD, PhD from 3:00 to 3:15 p.m. on Monday, April 18, 2005, during the 73rd Annual Meeting of the American Association of Neurological Surgeons in New Orleans. Co-authors of the study are Neelima B. Chauhan, PhD, and George J. Siegel, MD.
Researchers have previously demonstrated that antibodies injected into this region of the brain easily reach crucial areas affected by Alzheimer's disease, but not without serious side effects. Removal of excessive cerebral beta-amyloid has been shown to be effective in the treatment of Alzheimer's disease, but systemic passive immunization against beta-amyloid has been shown to be associated with serious inflammation problems secondary to antibodies reacting to beta-amyloid in normal structures, such as in blood vessels.
In this study, the injections were done in mice genetically engineered to develop Alzheimer's disease at both an early and late stage of the disease. The results demonstrate that a single intraventicular injection of antibodies against beta-amyloid substantially reduced the amount of amyloid in the brain by approximately 70 percent, even in those animals with a relatively severe stage of the disease. The results also showed that associated inflammatory responses in the brain were reduced. Furthermore, there was no sign of serious inflammatory problems like meningoencephalitis or perivascular hemorrhage, which were seen in earlier studies when similar antibodies were injected systemically, such as with intranasal methods of delivery.
The outcome of this study suggests that periodic intraventricular administration of antibodies against beta-amyloid is a potentially useful method for rapid reduction of both pre-existing amyloid plaques and associated inflammation. In addition, this method of passive immunization may be safer than other methods used because there were no associated inflammatory side effects in the brain.
"The data reported in this study provide strong support for a new approach in the treatment of Alzheimer's disease using a strategy involving injection of antibodies into the brain, without the serious side effects implicated in prior immunization strategies," said Dr. Lichtor.
Founded in 1931 as the Harvey Cushing Society, the American Association of Neurological Surgeons (AANS) is a scientific and educational association with more than 6,800 members worldwide. The AANS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. All active members of the AANS are certified by the American Board of Neurological Surgery, the Royal College of Physicians and Surgeons (Neurosurgery) of Canada or the Mexican Council of Neurological Surgery, AC. Neurological surgery is the medical specialty concerned with the prevention, diagnosis, treatment and rehabilitation of disorders that affect the entire nervous system, including the spinal column, spinal cord, brain and peripheral nerves.
