The roles of inflammation and immune mechanisms in Alzheimer's disease

AbstractThe Alzheimer's Association's Research roundtable met in April 2015 to explore the role of neuroinflammatory mechanisms in the progression of Alzheimer's disease (AD). The ability of innate immune cells, particularly microglia and astrocytes, to mediate neuroinflammation in AD has been implicated as a significant contributor to disease pathogenesis. Adaptive immunity, which plays an important role in responding to injury and some diseases of the central nervous system, may contribute to neuroinflammation in AD as well. Communication between the central and peripheral immune systems may also be important in AD. An increased understanding of the physiology of the innate immune system may aid the identification of new therapeutic targets or mechanisms. The development of predictive animal models and translatable neuroinflammation biomarkers for AD would also facilitate the advancement of novel treatments for innate immunity. Important challenges impeding the advancement of new therapeutic agents and strategies to overcome them were discussed

Clinical trials and late-stage drug development in Alzheimer’s disease: An appraisal from 1984 to 2014

The modern era of drug development for Alzheimer\u27s disease began with the proposal of the cholinergic hypothesis of memory impairment and the 1984 research criteria for Alzheimer\u27s disease. Since then, despite the evaluation of numerous potential treatments in clinical trials, only four cholinesterase inhibitors and memantine have shown sufficient safety and efficacy to allow marketing approval at an international level. Although this is probably because the other drugs tested were ineffective, inadequate clinical development methods have also been blamed for the failures. Here, we review the development of treatments for Alzheimer\u27s disease during the past 30 years, considering the drugs, potential targets, late‐stage clinical trials, development methods, emerging use of biomarkers and evolution of regulatory considerations in order to summarize advances and anticipate future developments. We have considered late‐stage Alzheimer\u27s disease drug development from 1984 to 2013, including individual clinical trials, systematic and qualitative reviews, meta‐analyses, methods, commentaries, position papers and guidelines. We then review the evolution of drugs in late clinical development, methods, biomarkers and regulatory issues. Although a range of small molecules and biological products against many targets have been investigated in clinical trials, the predominant drug targets have been the cholinergic system and the amyloid cascade. Trial methods have evolved incrementally: inclusion criteria have largely remained focused on mild‐to‐moderate Alzheimer\u27s disease criteria, recently extending to early or prodromal Alzheimer disease or ‘mild cognitive impairment due to Alzheimer\u27s disease’, for drugs considered to be disease modifying. The duration of trials has remained at 6–12 months for drugs intended to improve symptoms; 18‐ to 24‐month trials have been established for drugs expected to attenuate clinical course. Cognitive performance, activities of daily living, global change and severity ratings have persisted as the primary clinically relevant outcomes. Regulatory guidance and oversight have evolved to allow for enrichment of early‐stage Alzheimer\u27s disease trial samples using biomarkers and phase‐specific outcomes. In conclusion, validated drug targets for Alzheimer\u27s disease remain to be developed. Only drugs that affect an aspect of cholinergic function have shown consistent, but modest, clinical effects in late‐phase trials. There is opportunity for substantial improvements in drug discovery and clinical development methods

Nutrition for the ageing brain: towards evidence for an optimal diet

As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline

Advances in the therapy of Alzheimer's disease: Targeting amyloid beta and tau and perspectives for the future

Worldwide multidisciplinary translational research has led to a growing knowledge of the genetics and molecular pathogenesis of Alzheimer's disease (AD) indicating that pathophysiological brain alterations occur decades before clinical signs and symptoms of cognitive decline can be diagnosed. Consequently, therapeutic concepts and targets have been increasingly focused on early-stage illness before the onset of dementia; and distinct classes of compounds are now being tested in clinical trials. At present, there is a growing consensus that therapeutic progress in AD delaying disease progression would significantly decrease the expanding global burden. The evolving hypothesis- and evidence-based generation of new diagnostic research criteria for early-stage AD has positively impacted the development of clinical trial designs and the characterization of earlier and more specific target populations for trials in prodromal as well as in pre- and asymptomatic at-risk stages of AD