role of zinc in Alzheimer's

Adeona’s clinical studies of reaZin (prescription medical food) for Alzheimer's disease (Parts 1 and 2) and the planned clinical trial of AEN-100 (drug candidate) for mild to moderate Alzheimer’s disease grew out of observations by the Company, and now others, documenting a subclinical zinc deficiency in Alzheimer's disease patients.  There is also a significant body of published evidence implicating chronic copper exposure and elevated free serum copper levels in the progression of Alzheimer's disease and mild cognitive impairment. In 1992, results from an uncontrolled study of zinc therapy in Alzheimer's disease was reported to demonstrate cognitive improvement in 80% of subjects in as little as 3 to 6 months of treatment.

Due to the significant gastrointestinal side effects and intolerability of oral zinc therapy in such study, oral zinc therapy was discontinued and subjects were switched to zinc injections administered every other day, further underscoring the need for a better tolerated, convenient oral zinc therapy such as reaZin™. The hippocampus, an area of the brain that plays a critical role in short-term memory and is generally most affected in Alzheimer's disease, is believed to contain the highest levels of zinc in the brain. Hippocampal zinc is believed to play an important dual role as a synaptic neurotransmitter that modulates NMDA (N-methyl-D-aspartic acid) receptor activity limiting excitotoxicity and is a key component of hundreds of neuroprotective enzymes, a number of which are responsible for the degradation of amyloid beta.

Alzheimer's disease subjects have been reported to have lower levels of zinc in their cerebral spinal fluid, and cerebral spinal fluid levels of copper and zinc highly correlate with levels of amyloid beta 42 in cerebral spinal fluid, a biomarker of Alzheimer's disease. Zinc's role as an important NMDA receptor antagonist implies that by ameliorating the cerebral spinal fluid zinc deficiency in Alzheimer's disease patients, reaZin may demonstrate near term acute cognitive benefits, such as those demonstrated in the 1992 study described above, as well as reducing neurogeneration in the longer term. Current NMDA-receptor antagonists for Alzheimer's disease, such as Namenda® and Axura® (memantine), currently have estimated annualized sales of $2.6 billion.