Alzheimer Disease: Kennedy J

Schott JM, Kennedy J, Fox NC. · Institute of Neurology, Dementia Research Centre, National Hospital for Neurology and Neurosurgery, London, UK. · Curr Opin Neurol. · Pubmed #17102693 No free full text.

Abstract: PURPOSE OF REVIEW: In this paper, we review current concepts of Alzheimer's disease, recent progress in diagnosis and treatment and important developments in our understanding of its pathogenesis with a focus on beta-amyloid both as culprit and therapeutic target. RECENT FINDINGS: The amyloid cascade hypothesis of Alzheimer's disease pathogenesis continues to predominate with evidence suggesting that small oligomeric forms of Abeta-42 rather than fibrils or senile plaques are the key pathological substrates. The concept of mild cognitive impairment continues to be refined to define better those patients who will progress to Alzheimer's disease. Structural and functional imaging techniques and cerebrospinal fluid biomarkers are gaining acceptance as diagnostic markers of Alzheimer's disease, with a potentially exciting advance being the ability to image amyloid in vivo using novel positron emission tomography ligands. Whilst available treatments afford only symptomatic benefits, disease-modifying treatments may be within reach. Despite the halting of the first amyloid beta-vaccination trial due to adverse effects, amyloid immunotherapy continues to show promise, with new approaches already entering clinical trials. Other therapeutic strategies under investigation include inhibition of beta -and gamma-secretase, key enzymes implicated in Alzheimer's disease pathogenesis. SUMMARY: Current research demonstrates the potential for diagnostic strategies and disease modifying treatments to follow from an ever more detailed understanding of the molecular mechanisms underlying the pathogenesis of Alzheimer's disease.

Okello A, Edison P, Archer HA, Turkheimer FE, Kennedy J, Bullock R, Walker Z, Kennedy A, Fox N, Rossor M, Brooks DJ. · Division of Neuroscience and Mental Health, Faculty of Medicine, Imperial College London, London, UK. · Neurology. · Pubmed #19122031 No free full text.

Abstract: BACKGROUND: Activated microglia may play a role in the pathogenesis of Alzheimer disease (AD) as they cluster around beta-amyloid (Abeta) plaques. They are, therefore, a potential therapeutic target in both AD and its prodrome amnestic mild cognitive impairment (MCI). OBJECTIVE: To characterize in vivo with (11)C-(R)-PK11195 and (11)C-PIB PET the distribution of microglial activation and amyloid deposition in patients with amnestic MCI. METHODS: Fourteen subjects with MCI had (11)C-(R)-PK11195 and (11)C-PIB PET with psychometric tests. RESULTS: Seven out of 14 (50%) patients with MCI had increased cortical (11)C-PIB retention (p < 0.001) while 5 out of 13 (38%) subjects with MCI showed increased (11)C-(R)-PK11195 uptake. The MCI subgroup with increased (11)C-PIB retention also showed increased cortical (11)C-(R)-PK11195 binding (p < 0.036) though this increase only remained significant in frontal cortex after a correction for multiple comparisons. There was no correlation between regional levels of (11)C-(R)-PK11195 and (11)C-PIB binding in individual patients with MCI: only three of the five MCI cases with increased (11)C-(R)-PK11195 binding had increased levels of (11)C-PIB retention. CONCLUSIONS: Our findings indicate that, while amyloid deposition and microglial activation can be detected in vivo in around 50% of patients with mild cognitive impairment (MCI), these pathologies can occur independently. The detection of microglial activation in patients with MCI suggests that anti-inflammatory therapies may be relevant to the prevention of AD.

Knight WD, Kennedy J, Mead S, Rossor MN, Beck J, Collinge J, Mummery C. · Dementia Research Centre, Institute of Neurology, University College London, London, UK. · Eur J Neurol. · Pubmed #17594345 No free full text.

Abstract: We report the case of a 40 year-old woman who, at 38 years of age, developed insidious memory loss and, subsequently, progressive dementia satisfying criteria for probable Alzheimer's disease (AD) (NINCDS-ADRDA) [Neurology 1984; 34: 939]. Analysis of the presenilin 1 gene (PSEN1) revealed a 496_498delCTT mutation at codon 166. The amnestic presentation and absence of other features contrasts with the majority of other documented deletions which have been associated with spastic paraparesis. They are, however, consistent with the reported clinical phenotype in the majority of PSEN1 exon 6 mutations so far reported.

Kennedy J, Deberdt W, Siegal A, Micca J, Degenhardt E, Ahl J, Meyers A, Kaiser C, Baker RW. · University of Alberta and Chinook Regional Health System, Alberta, Canada. · Int J Geriatr Psychiatry. · Pubmed #16250069 No free full text.

Abstract: OBJECTIVE: This was an exploratory study of olanzapine as potential treatment for improvement in cognition in patients with Alzheimer's disease without prominent psychobehavioral symptoms. METHODS: Non-psychotic/non-agitated patients (n = 268) with Alzheimer's disease, who had baseline Mini-Mental State Examination (MMSE) scores of 14-26 were randomized to treatment with olanzapine (2.5 to 7.5 mg/d) or placebo for 26 weeks. The primary objectives were to determine if treatment with olanzapine improved cognition as indexed by the Alzheimer's disease Assessment Scale for Cognition (ADAS-Cog) and the Clinician's Interview-Based Impression of Change (CIBIC) after 26 weeks of therapy. RESULTS: Patients treated with olanzapine vs placebo experienced significant worsening ADAS-Cog scores at weeks 12 (p = 0.03) and 26 (p = 0.004). Changes in CIBIC scores were not significantly different between treatment groups at either assessment. A post hoc analysis revealed that olanzapine-treated patients with more cognitive impairment at baseline (MMSE scores of 14-18) (n = 35) experienced significantly greater deterioration in ADAS-Cog performance than patients in the placebo group (n = 24; p < 0.001); whereas in patients with less cognitive impairment (n = 78, baseline MMSE scores of 23-26) between-group ADAS-Cog changes were not significant. CONCLUSIONS: In this 26-week study non-psychotic/non-agitated patients with Alzheimer's disease treated with olanzapine experienced significant worsening of cognition as compared to placebo.