Alzheimer Disease: Friedhoff LT

Buxbaum JD, Cullen EI, Friedhoff LT. · Laboratory of Molecular Neuropsychiatry, Department of Psychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA. · Front Biosci. · Pubmed #11900994 No free full text.

Abstract: Epidemiological studies demonstrate that hypercholesterolemia is a risk factor for Alzheimer's disease (AD). As the generation and accumulation of the beta-amyloid peptide (Abeta) in the brain appears to be significant for the initiation and progression of AD, it is possible that cholesterol levels regulate Abeta formation and/or clearance. To test the effects of altering cholesterol on Abeta formation, we incubated cells with or without lovastatin acid, the active metabolite of the HMG-CoA reductase inhibitor lovastatin, and measured the fraction of Abeta formed from its precursor under each condition. We observed that treatment with lovastatin acid led to a profound decrease in the levels of Abeta formed. This effect was observed at concentrations of 0.05-5 microM, ranges where this compound is effective at inhibiting HMG-CoA reductase. To examine the effects of lovastatin on Abeta in vivo, human subjects who had elevated low-density lipoprotein cholesterol were treated during a double-blind, randomized study with 10-60-mg once-daily doses of a controlled-release formulation of lovastatin, or matching placebo. Serum Abeta concentrations were measured before and after up to 3 months of treatment. Mean and median changes from baseline in serum Abeta concentrations showed a significant (p < 0.0348), dose-dependent decrease. Differences between the 40- and 60-mg dose groups and placebo were statistically significant (Dunnett's p< 0.05). Our results suggest a mechanism by which hypercholesterolemia may increase risk for AD and indicate that lovastatin reduces Abeta formation and may thereby be effective in delaying the onset and/or slowing the progression of AD.

Friedhoff LT, Cullen EI, Geoghagen NS, Buxbaum JD. · Aura Laboratories, Inc., Andrx Corporation, Hackensack, NJ 07601, USA. · Int J Neuropsychopharmacol. · Pubmed #11466161 No free full text.

Abstract: The deposition of beta-amyloid (A beta) in neuronal plaques is believed to be crucial for the initiation and progression of Alzheimer's disease (AD). Studies in vitro have shown that inhibiting cholesterol metabolism with lovastatin, or its active metabolite lovastatin acid, lowers A beta production. To examine the effects of lovastatin on A beta in vivo, human subjects who had elevated low-density lipoprotein cholesterol were treated during a double-blind, randomized, placebo-controlled study with 10, 20, 40 or 60 mg once-daily doses of a controlled-release formulation of lovastatin, or matching placebo. Serum A beta concentrations were measured before and after up to 3 months of treatment. Mean and median changes from baseline in serum A beta concentrations showed a dose-dependent decrease, and analysis of variance indicated that treatment was statistically significant (p < 0.0348). Differences between the 40- and 60-mg dose groups and placebo were statistically significant (Dunnett's p < or = 0.05).

Burns A, Rossor M, Hecker J, Gauthier S, Petit H, Möller HJ, Rogers SL, Friedhoff LT. · Withington Hospital, Manchester, UK. · Dement Geriatr Cogn Disord. · Pubmed #10325453 No free full text.

Abstract: Donepezil has been shown to be well tolerated and to improve cognition and global function in patients with mild to moderately severe Alzheimer's disease (AD). The current trial was undertaken to investigate further the efficacy and safety of donepezil, in a multinational setting, in patients with mild to moderately severe AD. This 30-week, placebo-controlled, parallel-group study consisted of a 24-week, double-blind treatment phase followed by a 6-week, single-blind, placebo washout. Eight hundred and eighteen patients with mild to moderately severe AD were randomly allocated to treatment with single, daily doses of 5 or 10 mg donepezil, or placebo. The two primary efficacy measures were: a cognitive performance test, the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and a global evaluation, the Clinician's Interview-Based Impression of Change with caregiver input (CIBIC plus). Secondary outcome measures included the Sum of the Boxes of the Clinical Dementia Rating Scale (CDR-SB), a modified Interview for Deterioration in Daily living activities in Dementia (IDDD) and a patient rated quality of life assessment. Statistically significant improvements in cognitive and global function were observed, as evaluated by ADAS-cog and CIBIC plus, respectively, in both the 5 and 10 mg/day donepezil groups, compared with placebo. Treatment-associated changes were also observed in functional skills, as shown by improved scores on the CDR-SB and the complex-tasks component of the IDDD. A dose-response effect was evident, with the 10 mg/day donepezil group demonstrating greater benefits in all outcome measures than the 5 mg/day group. Donepezil was well tolerated by this patient population and did not produce any clinically significant laboratory test abnormalities. The results of this study confirm that donepezil is effective and well tolerated in treating the symptoms of mild to moderately severe AD.