Nonsteroidal anti-inflammatory drug use and Alzheimer's disease: a case-control study in Rochester, Minnesota, 1980 through 1984

Alzheimer's Disease Treatment: The Search for a Breakthrough

As the search for modalities to cure Alzheimer's disease (AD) has made slow progress, research has now turned to innovative pathways involving neural and peripheral inflammation and neuro-regeneration. Widely used AD treatments provide only symptomatic relief without changing the disease course. The recently FDA-approved anti-amyloid drugs, aducanumab and lecanemab, have demonstrated unclear real-world efficacy with a substantial side effect profile. Interest is growing in targeting the early stages of AD before irreversible pathologic changes so that cognitive function and neuronal viability can be preserved. Neuroinflammation is a fundamental feature of AD that involves complex relationships among cerebral immune cells and pro-inflammatory cytokines, which could be altered pharmacologically by AD therapy. Here, we provide an overview of the manipulations attempted in pre-clinical experiments. These include inhibition of microglial receptors, attenuation of inflammation and enhancement of toxin-clearing autophagy. In addition, modulation of the microbiome-brain-gut axis, dietary changes, and increased mental and physical exercise are under evaluation as ways to optimize brain health. As the scientific and medical communities work together, new solutions may be on the horizon to slow or halt AD progression.

Prevalence of cognitive impairment in patients with rheumatoid arthritis: a cross sectional study

OBJECTIVE

To explore the role of chronic inflammation in rheumatoid arthritis (RA) on cognition.

METHODS AND ANALYSIS

Six hundred sixty-one men and women aged ≥55 years who fulfilled the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria for RA were recruited from three healthcare trusts in the United Kingdom (UK) between May 2018 and March 2020. Study participants took part in interviews which captured sociodemographic information, followed by an assessment of cognition. RA specific clinical characteristics were obtained from hospital medical records. Participants were cognitively assessed using the Montreal Cognitive Assessment (MoCA) and were classified as cognitively impaired if they scored ≤27/30 points. Linear regression analyses were conducted to identify which demographic and clinical variables were potential predictors of cognitive impairment.

RESULTS

The average age of participants was 67.6 years and 67% (444/661) were women. 72% (458/634; 95% CI 0.69 to 0.76) of participants were classified as cognitively impaired (MoCA≤27). Greater cognitive impairment was associated with older age (p = .006), being male (p = .041) and higher disease activity score (DAS28) (with moderate (DAS28 > 3.1) (p = 0.008) and high (DAS28 > 5.1) (p = 0.008)) compared to those in remission (DAS28 ≤ 2.6). There was no association between MoCA score and education, disease duration, RF status, anti-cyclic citrullinated peptide (anti-CCP) status, RA medication type or use of glucocorticoids or non-steroidal anti-inflammatory drugs (p > 0.05).

CONCLUSION

This study suggests that cognitive impairment is highly prevalent in older adults with RA. This impairment appears to be associated with higher RA disease activity and supports the concept that chronic systemic inflammation might accelerate cognitive decline. This underlines the importance of controlling the inflammatory response.

The link between cutaneous inflammation and cognitive impairment

Cognitive impairment is a symptom of neurological disorders, including dementia and Alzheimer's disease; and mild cognitive impairment can be a precursor of both disorders. Aged humans and animal models with other systemic disorders, such as cardiovascular diseases and diabetes, display a higher incidence of cognitive decline. Epidemiological studies have shown that the incidence of cognitive impairment also is higher in subjects with certain inflammatory skin disorders, including psoriasis and chronic eczematous dermatitis. Chronologically aged individuals exhibit increased cutaneous inflammation and elevated circulating cytokine levels, linked to alterations in epidermal function, which itself can induce cutaneous inflammation. Conversely, strategies that improve epidermal function can lower cytokine levels in both the skin and circulation. Thus, it seems likely that epidermal dysfunction could contribute, at least in part, to the development of chronic low-grade inflammation, also termed 'inflammaging', in the elderly. The evidence of cognitive impairment in patients with inflammatory dermatoses suggests a link between cutaneous inflammation and cognitive impairment. Because of the pathogenic role of epidermal dysfunction in ageing-associated cutaneous inflammation, improvements in epidermal function could be an alternative approach for mitigation of the ageing-associated decline in cognitive function.

Osteoarthritis and APOE4 Interact to Influence Memory Decline in Non-Demented Older People

Background: The question that whether the presence of osteoarthritis (OA) can modify the effects of apolipoprotein E4 (APOE4) genotype on longitudinal change in cognitive performance among non-demented older people remains unclear. Objective: To examine whether the association of APOE4 genotype with change in verbal episodic memory over time is modified by the presence of OA among non-demented older people. Methods: Longitudinal data from 1,400 non-demented older people were obtained from the Alzheimer’s Disease Neuroimaging Initiative database. The sample included 466 healthy individuals and 934 mild cognitive impairment. The effects of the OA×APOE4 genotype interaction term on longitudinal change in cognitive performance were examined using linear mixed-effects regression models. Global cognition was assessed by the Mini-Mental State Examination score and Clinical Dementia Rating–Sum of Boxes. Verbal episodic memory was evaluated by the Rey Auditory Verbal Learning Test (RAVLT) immediate recall and delayed recall score. Results: We found that OA interacted with APOE4 genotype to influence longitudinal change in verbal episodic memory (as assessed by RAVLT immediate recall score) but not global cognition. Specifically, the OA–/APOE4+ group had a steeper decline in RAVLT immediate recall score compared with the OA+/APOE4+ group. However, there was no difference in RAVLT immediate recall score between OA–/APOE4–and OA+/APOE4–individuals. Conclusion: Our study suggested that the association of APOE4 genotype with change in RAVLT immediate recall score over time is modified by the presence of OA at earliest stages of the disease.

Neuroinflammatory Markers: Key Indicators in the Pathology of Neurodegenerative Diseases

Neuroinflammation, a protective response of the central nervous system (CNS), is associated with the pathogenesis of neurodegenerative diseases. The CNS is composed of neurons and glial cells consisting of microglia, oligodendrocytes, and astrocytes. Entry of any foreign pathogen activates the glial cells (astrocytes and microglia) and overactivation of these cells triggers the release of various neuroinflammatory markers (NMs), such as the tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-1β (IL-10), nitric oxide (NO), and cyclooxygenase-2 (COX-2), among others. Various studies have shown the role of neuroinflammatory markers in the occurrence, diagnosis, and treatment of neurodegenerative diseases. These markers also trigger the formation of various other factors responsible for causing several neuronal diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), multiple sclerosis (MS), ischemia, and several others. This comprehensive review aims to reveal the mechanism of neuroinflammatory markers (NMs), which could cause different neurodegenerative disorders. Important NMs may represent pathophysiologic processes leading to the generation of neurodegenerative diseases. In addition, various molecular alterations related to neurodegenerative diseases are discussed. Identifying these NMs may assist in the early diagnosis and detection of therapeutic targets for treating various neurodegenerative diseases.

Mechanistic role of boswellic acids in Alzheimer's disease: Emphasis on anti-inflammatory properties

The resin/gum of Boswellia species belonging to the family of Burseraceae is a naturally occurring mixture of bioactive compounds, which was traditionally used as a folk medicine to treat conditions like chronic inflammation. Several research studies have also explored its' therapeutic potential against multiple neurodegenerative diseases such as Alzheimer's disease (AD). The main chemical constituents of this gum include boswellic acids (BAs) like 3-O-acetyl-11-keto-β boswellic acid (AKBA) that possess potent anti-inflammatory and neuroprotective properties in AD. It is also involved in inhibiting the acetylcholinesterase (AChE) activity in the cholinergic pathway and improve choline levels as well as its binding with nicotinic receptors to produce anti-inflammatory effects. Multiple shreds of evidence have demonstrated that BAs modulate key molecular targets and signalling pathways like 5-lipoxygenase/cyclooxygenase, Nrf2, NF-kB, cholinergic, amyloid-beta (Aβ), and neurofibrillary tangles formation (NFTs) that are involved in AD progression. The present review focuses on the possible mechanistic therapeutic role of BAs in modulating the 5-LOX/COX pathway in arachidonic acid metabolism, activating Nrf2 through binding of ARE, inhibiting NF-kB and AChE activity. In addition, an inhibition of amyloid plaques (Aβ) and neurofibrillary tangles (NFTs) induced neurotoxicity and neuroinflammation in AD by BAs is also discussed in this review. We have also highlighted that BAs possess beneficial effects in AD by targeting multiple molecular pathways and makes it an emerging drug candidate for treating neurodegenerative diseases.

Targeting innate immunity to protect and cure Alzheimer's disease: opportunities and pitfalls

Innate immunity has been the focus of many new directions to understand the mechanisms involved in the aetiology of brain diseases, especially Alzheimer's disease (AD). AD is a multifactorial disorder, with the innate immune response and neuroinflammation at the forefront of the pathology. Thus, microglial cells along with peripheral circulating monocytes and more generally the innate immune response have been the target of several pre-clinical and clinical studies. More than a decade ago, inhibiting innate immune cells was considered to be the critical angle for preventing and treating brain diseases. After the failing of numerous clinical trials and the discovery that it may actually be the opposite in various pre-clinical models, the field has changed considerably. Here, we present both sides of the story with a particular emphasis on the beneficial properties of innate immune cells and how they can be targeted to have neuroprotective properties.

Neuroinflammation in Alzheimer's disease and beneficial action of luteolin

Alzheimer's disease (AD), already the world's most common form of dementia, is projected to continue increasing in prevalence over the next several decades. The current lack of understanding of the pathogenesis of AD has hampered the development of effective treatments. Historically, AD research has been predicated on the amyloid cascade hypothesis (ACH), which attributes disease progression to the build-up of amyloid protein. However, multiple clinical studies of drugs interfering with ACH have failed to show any benefit demonstrating that AD etiology is more complex than previously thought. Here we review the current literature on the emerging key role of neuroinflammation, especially activation of microglia, in AD pathogenesis. Moreover, we provide compelling evidence that certain flavonoids, especially luteolin formulated in olive pomace oil together with hydroxytyrosol, offers a reasonable prophylactic treatment approach due to its many beneficial actions.

The Contribution of Formyl Peptide Receptor Dysfunction to the Course of Neuroinflammation: A Potential Role in the Brain Pathology

Chronic inflammatory processes within the central nervous system (CNS) are in part responsible for the development of neurodegenerative and psychiatric diseases. These processes are associated with, among other things, the increased and disturbed activation of microglia and the elevated production of proinflammatory factors. Recent studies indicated that the disruption of the process of resolution of inflammation (RoI) may be the cause of CNS disorders. It is shown that the RoI is regulated by endogenous molecules called specialized pro-resolving mediators (SPMs), which interact with specific membrane receptors. Some SPMs activate formyl peptide receptors (FPRs), which belong to the family of seven-transmembrane G protein-coupled receptors. These receptors take part not only in the proinflammatory response but also in the resolution of the inflammation process. Therefore, the activation of FPRs might have complex consequences.

This review discusses the potential role of FPRs, and in particular the role of FPR2 subtype, in the brain under physiological and pathological conditions and their involvement in processes underlying neurodegenerative and psychiatric disorders as well as ischemia, the pathogenesis of which involves the dysfunction of inflammatory processes.

Microglial memory of early life stress and inflammation: Susceptibility to neurodegeneration in adulthood

We review evidence supporting the role of early life programming in the susceptibility for adult neurodegenerative diseases while highlighting questions and proposing avenues for future research to advance our understanding of this fundamental process. The key elements of this phenomenon are chronic stress, neuroinflammation triggering microglial polarization, microglial memory and their connection to neurodegeneration. We review the mediating mechanisms which may function as early biomarkers of increased susceptibility for neurodegeneration. Can we devise novel early life modifying interventions to steer developmental trajectories to their optimum?

Inflammation in Neurological Disorders: The Thin Boundary Between Brain and Periphery

Significance: Accumulating evidence suggests that inflammation is a major contributor in the pathogenesis of several highly prevalent, but also rare, neurological diseases. In particular, the neurodegenerative processes of Alzheimer's disease (AD), vascular dementia (VAD), Parkinson's disease (PD), and multiple sclerosis (MS) are fueled by neuroinflammation, which, in turn, is accompanied by a parallel systemic immune dysregulation. This cross-talk between periphery and the brain becomes substantial when the blood-brain barrier loses its integrity, as often occurs in the course of these diseases. It has been hypothesized that the perpetual bidirectional flux of inflammatory mediators is not a mere "static" collateral effect of the neurodegeneration, but represents a proactive phenomenon sparking and driving the neuropathological processes. However, the upstream/downstream relationship between inflammatory events and neurological pathology is still unclear. Recent Advances: Solid recent evidence clearly suggests that metabolic factors, systemic infections, Microbiota dysbiosis, and oxidative stress are implicated, although to a different extent, in the development in brain diseases. Critical Issues: Here, we reviewed the most solid published evidence supporting the implication of the axis systemic inflammation-neuroinflammation-neurodegeneration in the pathogenesis of AD, VAD, PD, and MS, highlighting the possible cause of the putative downstream component of the axis. Future Directions: Reaching a definitive clinical/epidemiological appreciation of the etiopathogenic significance of the connection between peripheral and brain inflammation in neurologic disorders is pivotal since it could open novel therapeutic avenues for these diseases.

Neuroimmune interactions in Alzheimer's disease-New frontier with old challenges?

The perceived role of the immune system in neurodegenerative diseases has undergone drastic changes over time. Initially considered as a passive bystander, then condemned as a mediator of neurodegeneration and now established as an important player in the pathogenetic cascade, neuroimmune interactions have come a long way to arrive center stage in Alzheimer's disease research. Despite major breakthroughs in recent years, basic questions remain unanswered as conflicting data describe immune overactivation, inadequate response or exhaustion of the immune system in neurodegenerative diseases. Furthermore, difficulties in translating in vitro and in vivo studies in model systems to the complex human disease condition with multiple overlapping pathologies and the long disease duration in patients suffering from neurodegenerative diseases have hampered progress. Development of novel, advanced model systems, as well as new technologies to interrogate existing disease models and valuable collections of human tissue samples, including brain tissue in parallel with improved imaging and biomarker technologies are guiding the way to better understand the role of the immune system in Alzheimer's disease with hopes for more effective interventions in the future.

Anti-Inflammatory Triterpenoids from Mysterious Mushroom Ganoderma Lucidum and Their Potential Possibility in Modern Medicine

Ganoderma lucidum, a mushroom long used in the East for a broad range of disorders, contains numerous pharmacologically active compounds. Very important of them are highly oxygenated anti-inflammatory triterpenes, which are the aim of this mini-review.

Interleukin 9 alterations linked to alzheimer disease in african americans

OBJECTIVE

Compared to older Caucasians, older African Americans have higher risks of developing Alzheimer disease (AD) and lower cerebrospinal fluid (CSF) tau biomarker levels. It is not known whether tau-related differences begin earlier in life or whether race modifies other AD-related biomarkers such as inflammatory proteins.

METHODS

We performed multiplex cytokine analysis in a healthy middle-aged cohort with family history of AD (n = 68) and an older cohort (n = 125) with normal cognition (NC), mild cognitive impairment, or AD dementia. After determining baseline interleukin (IL)-9 level and AD-associated IL-9 change to differ according to race, we performed immunohistochemical analysis for proteins mechanistically linked to IL-9 in brains of African Americans and Caucasians (n = 38), and analyzed postmortem IL-9-related gene expression profiles in the publicly available Mount Sinai cohort (26 African Americans and 180 Caucasians).

RESULTS

Compared to Caucasians with NC, African Americans with NC had lower CSF tau, p-Tau181 , and IL-9 levels in both living cohorts. Conversely, AD was only correlated with increased CSF IL-9 levels in African Americans but not Caucasians. Immunohistochemical analysis revealed perivascular, neuronal, and glial cells immunoreactive to IL-9, and quantitative analysis in independent US cohorts showed AD to correlate with molecular changes (upstream differentiation marker and downstream effector cell marker) of IL-9 upregulation only in African Americans but not Caucasians.

INTERPRETATION

Baseline and AD-associated IL-9 differences between African Americans and Caucasians point to distinct molecular phenotypes for AD according to ancestry. Genetic and nongenetic factors need to be considered in future AD research involving unique populations. ANN NEUROL 2019;86:407-418.

Inflammatory mechanisms in neurodegeneration

This review discusses the profound connection between microglia, neuroinflammation, and Alzheimer's disease (AD). Theories have been postulated, tested, and modified over several decades. The findings have further bolstered the belief that microglia-mediated inflammation is both a product and contributor to AD pathology and progression. Distinct microglia phenotypes and their function, microglial recognition and response to protein aggregates in AD, and the overall role of microglia in AD are areas that have received considerable research attention and yielded significant results. The following article provides a historical perspective of microglia, a detailed discussion of multiple microglia phenotypes including dark microglia, and a review of a number of areas where microglia intersect with AD and other pathological neurological processes. The overall breadth of important discoveries achieved in these areas significantly strengthens the hypothesis that neuroinflammation plays a key role in AD. Future determination of the exact mechanisms by which microglia respond to, and attempt to mitigate, protein aggregation in AD may lead to new therapeutic strategies.

Inflammation as a central mechanism in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is characterized by cognitive decline and the presence of two core pathologies, amyloid β plaques and neurofibrillary tangles. Over the last decade, the presence of a sustained immune response in the brain has emerged as a third core pathology in AD. The sustained activation of the brain's resident macrophages (microglia) and other immune cells has been demonstrated to exacerbate both amyloid and tau pathology and may serve as a link in the pathogenesis of the disorder. In the following review, we provide an overview of inflammation in AD and a detailed coverage of a number of microglia-related signaling mechanisms that have been implicated in AD. Additional information on microglia signaling and a number of cytokines in AD are also reviewed. We also review the potential connection of risk factors for AD and how they may be related to inflammatory mechanisms.

Mefenamic Acid Attenuates Chronic Alcohol Induced Cognitive Impairment in Zebrafish: Possible Role of Cholinergic Pathway

Based on the scientific evidence supporting the neuroinflammatory response contributes the cognitive impairment associated with chronic alcoholism and the neuroprotective actions of mefenamic acid with reversal of memory loss and brain inflammation in mice, this study was designed to evaluate the effect of mefenamic acid against chronic alcohol induced cognitive impairment in zebrafish model. Zebrafish were grouped and subjected to normal behavioral analysis in light-dark chamber for 10 days. The preference to dark compartment was noted in zebrafish. Zebrafish were grouped and exposed to escalating doses of alcohol for 28 days with and without mefenamic acid exposure (100 and 200 µg/L) and subjected to a fear conditioning passive avoidance task from day 13 of 28. The cognitive evaluation was performed for 10 days and the brain tissue was isolated to estimate acetylcholinesterase activity. In cognitive evaluation study, the normal zebrafish retained the memory of the learned task and avoided the dark. The alcohol exposed zebrafish showed impairment in retaining the memory of learned task. Mefenamic acid exposed zebrafish showed a significant protection against cognitive impairment caused by alcohol and retained the memory of learned task with a significant decrease in AChE activity in brain homogenate compared to alcohol exposed zebrafish. The results of this study suggest that the memory enhancing activity of mefenamic acid might be due to activation of cholinergic transmission that has protected neuroinflammatory and neurodegenerative conditions caused by alcohol.

The Inflammatory Continuum of Traumatic Brain Injury and Alzheimer's Disease

The post-injury inflammatory response is a key mediator in long-term recovery from traumatic brain injury (TBI). Moreover, the immune response to TBI, mediated by microglia and macrophages, is influenced by existing brain pathology and by secondary immune challenges. For example, recent evidence shows that the presence of beta-amyloid and phosphorylated tau protein, two hallmark features of AD that increase during normal aging, substantially alter the macrophage response to TBI. Additional data demonstrate that post-injury microglia are “primed” and become hyper-reactive following a subsequent acute immune challenge thereby worsening recovery. These alterations may increase the incidence of neuropsychiatric complications after TBI and may also increase the frequency of neurodegenerative pathology. Therefore, the purpose of this review is to summarize experimental studies examining the relationship between TBI and development of AD-like pathology with an emphasis on the acute and chronic microglial and macrophage response following injury. Furthermore, studies will be highlighted that examine the degree to which beta-amyloid and tau accumulation as well as pre- and post-injury immune stressors influence outcome after TBI. Collectively, the studies described in this review suggest that the brain’s immune response to injury is a key mediator in recovery, and if compromised by previous, coincident, or subsequent immune stressors, post-injury pathology and behavioral recovery will be altered.

Risk factors for dementia

There is little doubt that dementia is a very common cause of disability and dependency in our society. Since dementia of whatever type is usually more common with increasing age, then as population demographics change, so will the prevalence of dementia. Dementia is a generic term and the objective for clinicians, once dementia is suspected, is to attempt to define the cause. Alzheimer's disease is the most common cause of dementia, and in most centres vascular dementia would feature as the next most common aetiology. In some centres, Lewy body dementia is the second most common cause. Mixed Alzheimer's disease and vascular dementia would also feature high on the list at most centres.

Mean Daily Dosage of Aspirin and the Risk of Incident Alzheimer's Dementia in Patients with Type 2 Diabetes Mellitus: A Nationwide Retrospective Cohort Study in Taiwan

Background. Type 2 diabetes mellitus patients are known to have higher risk of developing dementia while aspirin use has been shown to prevent incident dementia. This study was conducted to evaluate the potential benefits of aspirin use on dementia in patients with type 2 diabetes mellitus and identify the appropriate dosage of aspirin that provides the most benefit. Method. A Taiwan nationwide, population-based retrospective 8-year study was employed to analyze the association between the use of aspirin and incidence of dementia including Alzheimer's disease and non-Alzheimer's dementia using multivariate Cox-proportional hazards regression model and adjusting for several potential confounders. Results. Regular aspirin use in mean daily dosage of within 40 mg was associated with a decreased risk of developing incident Alzheimer's dementia in patients with type 2 diabetes mellitus (adjusted HR of 0.51 with 95% CI of 0.27-0.97, p value 0.041). Conclusion. A mean daily dosage of aspirin use within 40 mg might decrease the risk of developing Alzheimer's disease in patients with type 2 diabetes mellitus.

Histamine Induces Alzheimer's Disease-Like Blood Brain Barrier Breach and Local Cellular Responses in Mouse Brain Organotypic Cultures

Among the top ten causes of death in the United States, Alzheimer's disease (AD) is the only one that cannot be cured, prevented, or even slowed down at present. Significant efforts have been exerted in generating model systems to delineate the mechanism as well as establishing platforms for drug screening. In this study, a promising candidate model utilizing primary mouse brain organotypic (MBO) cultures is reported. For the first time, we have demonstrated that the MBO cultures exhibit increased blood brain barrier (BBB) permeability as shown by IgG leakage into the brain parenchyma, astrocyte activation as evidenced by increased expression of glial fibrillary acidic protein (GFAP), and neuronal damage-response as suggested by increased vimentin-positive neurons occur upon histamine treatment. Identical responses-a breakdown of the BBB, astrocyte activation, and neuronal expression of vimentin-were then demonstrated in brains from AD patients compared to age-matched controls, consistent with other reports. Thus, the histamine-treated MBO culture system may provide a valuable tool in combating AD.

Non-steroidal anti-inflammatory drug use and essential tremor

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to be inversely related to Parkinson's disease and Alzheimer's disease, both of which may share common mechanisms with essential tremor (ET). Use of these medications has not been studied in ET cases vs. controls.

OBJECTIVE

To investigate the relationships between NSAID (esp. ibuprofen) and aspirin use and ET.

METHODS

Subjects were enrolled in a case-control study of the environmental epidemiology of ET at the Columbia University Medical Center (CUMC; 2009-2014). We compared 92 ET cases to 107 controls (∼1:1 matching) in terms of self-reported NSAID (esp. ibuprofen) and aspirin use.

RESULTS

The proportion of NSAID or aspirin users (current or past) was similar in ET cases and controls (for current user, p = 0.66; for past user, p = 0.90). Among users, however, the total dosage of ibuprofen (frequency in past year × number of tablets taken at a time × typical average strength of tablets) was higher in controls than ET cases (p = 0.04). ET cases and controls did not differ with respect to aspirin use in the past year.

CONCLUSION

The proportion of NSAID or aspirin users did not differ in ET cases or controls; yet interestingly, ibuprofen use was less in ET cases than in controls. The latter raises the possibility that ibuprofen use could have a potential protective role in ET.

Therapeutic implications of the prostaglandin pathway in Alzheimer's disease

An important pathologic hallmark of Alzheimer's disease (AD) is neuroinflammation, a process characterized in AD by disproportionate activation of cells (microglia and astrocytes, primarily) of the non-specific innate immune system within the CNS. While inflammation itself is not intrinsically detrimental, a delicate balance of pro- and anti-inflammatory signals must be maintained to ensure that long-term exaggerated responses do not damage the brain over time. Non-steroidal anti-inflammatory drugs (NSAIDs) represent a broad class of powerful therapeutics that temper inflammation by inhibiting cyclooxygenase-mediated signaling pathways including prostaglandins, which are the principal mediators of CNS neuroinflammation. While historically used to treat discrete or systemic inflammatory conditions, epidemiologic evidence suggests that protracted NSAID use may delay AD onset, as well as decrease disease severity and rate of progression. Unfortunately, clinical trials with NSAIDs have thus far yielded disappointing results, including premature discontinuation of a large-scale prevention trial due to unexpected cardiovascular side effects. Here we review the literature and make the argument that more targeted exploitation of downstream prostaglandin signaling pathways may offer significant therapeutic benefits for AD while minimizing adverse side effects. Directed strategies such as these may ultimately help to delay the deleterious consequences of brain aging and might someday lead to new therapies for AD and other chronic neurodegenerative diseases.

Inflammatory processes and Alzheimer’s disease

The inflammatory hypothesis of Alzheimer's disease, which states that anti-inflammatory drugs could have beneficial effects on the pathophysiology of Alzheimer's disease, has been extensively investigated in clinical, epidemiological and basic research studies over the last 20 years. However, despite much hope, the hypothesis remains unproven. Although the results from the first small clinical trial with an anti-inflammatory agent in Alzheimer's disease appeared promising, subsequent trials with a variety of anti-inflammatory agents have failed to show beneficial effects. There are many potential reasons for this including drug selection, drug dose, timing and duration of treatment. This article reviews evidence in support of the inflammatory hypothesis in Alzheimer's disease, as well as the progress of clinical trials using specific anti-inflammatory treatment regimens. It is concluded that such treatments should not be recommended, although additional investigation is warranted.

Neuropathology and treatment of Alzheimer disease: did we lose the forest for the trees?

Although amyloid-beta-containing senile plaques and phospho-tau containing neurofibrillary tangles are hallmark lesions of Alzheimer disease (AD), neither is specific for AD, nor even a marker of AD. Rather, they are empirical lesions that require close correlation with age and clinical signs for optimal interpretation. In essence, these lesions represent the effect rather than the cause of disease. In this review, we discuss diagnostic criteria for AD, the relationship between pathology, pathogenesis and multiple treatment approaches that have so far been disappointing, including those that presume to address pathological lesions. An acceptance that lesion-based therapies do not address etiology or rate-limiting pathogenic factors is probably necessary for the best chance of significant advances that have thus far been elusive.

The amyloid cascade-inflammatory hypothesis of Alzheimer disease: implications for therapy

The amyloid cascade hypothesis is widely accepted as the centerpiece of Alzheimer disease (AD) pathogenesis. It proposes that abnormal production of beta amyloid protein (Abeta) is the cause of AD and that the neurotoxicity is due to Abeta itself or its oligomeric forms. We suggest that this, in itself, cannot be the cause of AD because demonstrating such toxicity requires micromolar concentrations of these Abeta forms, while their levels in brain are a million times lower in the picomolar range. AD probably results from the inflammatory response induced by extracellular Abeta deposits, which later become enhanced by aggregates of tau. The inflammatory response, which is driven by activated microglia, increases over time as the disease progresses. Disease-modifying therapeutic attempts to date have failed and may continue to do so as long as the central role of inflammation is not taken into account. Multiple epidemiological and animal model studies show that NSAIDs, the most widely used antiinflammatory agents, have a substantial sparing effect on AD. These studies provide a proof of concept regarding the anti-inflammatory approach to disease modification. Biomarker studies have indicated that early intervention may be necessary. They have established that disease onset occurs more than a decade before it becomes clinically evident. By combining biomarker and pathological data, it is possible to define six phases of disease development, each separated by about 5 years. Phase one can be identified by decreases in Abeta in the CSF, phase 2 by increases of tau in the CSF plus clear evidence of Abeta brain deposits by PET scanning, phase 3 by slight decreases in brain metabolic rate by PET-FDG scanning, phase 4 by slight decreases in brain volume by MRI scanning plus minimal cognitive impairment, phase 5 by increased scanning abnormalities plus clinical diagnosis of AD, and phase 6 by advanced AD requiring institutional care. Utilization of antiinflammatory agents early in the disease process remains an overlooked therapeutic opportunity. Such agents, while not preventative, have the advantage of being able to inhibit the consequences of both Abeta and tau aggregation. Since there is more than a decade between disease onset and cognitive decline, a window of opportunity exists to introduce truly effective disease-modifying regimens. Taking advantage of this opportunity is the challenge for the future.

Inflammation in Alzheimer disease-a brief review of the basic science and clinical literature

Biochemical and neuropathological studies of brains from individuals with Alzheimer disease (AD) provide clear evidence for an activation of inflammatory pathways, and long-term use of anti-inflammatory drugs is linked with reduced risk to develop the disease. As cause and effect relationships between inflammation and AD are being worked out, there is a realization that some components of this complex molecular and cellular machinery are most likely promoting pathological processes leading to AD, whereas other components serve to do the opposite. The challenge will be to find ways of fine tuning inflammation to delay, prevent, or treat AD.

Current therapeutic options for Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease in the developed world. The increasing life expectancy in the last years has led to an increase in the prevalence of this age-related condition and has posed an important medical and social challenge for developed societies. The mainstays of current therapy for AD rely on the cholinergic hypothesis developed more than 20 years ago. These compounds, known as acetylcholinesterase inhibitors (AChEIs), inhibit the cholinesterases and aim at improving the brain synaptic availability of acetylcholine. These drugs have been approved for the treatment of AD based on pivotal clinical trials showing modest symptomatic benefit on cognitive, behavioral, and global measures. Memantine, an NMDA antagonist, has been recently included as a therapeutic option for AD. Memantine can be combined safely with AChEIs for an additional symptomatic benefit. During the last years our understanding of the mechanisms underlying the pathogenesis of AD has markedly expanded. Several putative neuroprotective drugs are thoroughly investigated and many of them have reached the clinical arena. It can be anticipated that some of these drugs will be able to slow/prevent the progression of this condition in the near future.

Neuroinflammatory processes in Alzheimer's disease

Generation of neurotoxic amyloid beta peptides and their deposition along with neurofibrillary tangle formation represent key pathological hallmarks in Alzheimer's disease (AD). Recent evidence suggests that inflammation may be a third important component which, once initiated in response to neurodegeneration or dysfunction, may actively contribute to disease progression and chronicity. Various neuroinflammatory mediators including complement activators and inhibitors, chemokines, cytokines, radical oxygen species and inflammatory enzyme systems are expressed and released by microglia, astrocytes and neurons in the AD brain. Degeneration of aminergic brain stem nuclei including the locus ceruleus and the nucleus basalis of Meynert may facilitate the occurrence of inflammation in their projection areas given the antiinflammatory and neuroprotective action of their key transmitters norepinephrine and acetylcholine. While inflammation has been thought to arise secondary to degeneration, recent experiments demonstrated that inflammatory mediators may stimulate amyloid precursor protein processing by various means and therefore can establish a vicious cycle. Despite the fact that some aspects of inflammation may even be protective for bystander neurons, antiinflammatory treatment strategies should therefore be considered. Non-steroidal anti-inflammatory drugs have been shown to reduce the risk and delay the onset to develop AD. While, the precise molecular mechanism underlying this effect is still unknown, a number of possible mechanisms including cyclooxygenase 2 or gamma-secretase inhibition and activation of the peroxisome proliferator activated receptor gamma may alone or, more likely, in concert account for the epidemiologically observed protection.

Inflammation in Alzheimer's disease: relevance to pathogenesis and therapy

Evidence for the involvement of inflammatory processes in the pathogenesis of Alzheimer's disease (AD) has been documented for a long time. However, the inflammation hypothesis in relation to AD pathology has emerged relatively recently. Even in this hypothesis, the inflammatory reaction is still considered to be a downstream effect of the accumulated proteins (amyloid beta (Abeta) and tau). This review aims to highlight the importance of the immune processes involved in AD pathogenesis based on the outcomes of the two major inflammation-relevant treatment strategies against AD developed and tested to date in animal studies and human clinical trials - the use of anti-inflammatory drugs and immunisation against Abeta.

Drug-related damage of the ageing gastrointestinal tract

Drug use increases with age and the elderly is at increased risk of adverse drug reactions. Gastrointestinal adverse effects are one of the most often reported. Serious event are mostly caused by NSAIDs and/or aspirin which are the most widely prescribed medications in the world. NSAIDs and/or aspirin use are associated with complications from both the upper and the lower gastrointestinal tract. The risk of these complications depends on presence of risk factors, and age is the most frequent and relevant one. At-risk patients should be on prevention strategies including the use of the lowest effective dose, co-therapy with a gastroprotective agents or use of a COX-2 selective agent. Treatment of Helicobacter pylori infection is beneficial in patients starting therapy with these agents, especially in the presence of ulcer history. The best strategy to prevent lower GI complications has yet to be defined.

Involvement of Fc receptors in disorders of the central nervous system

Immunoglobulins are proteins with a highly variable antigen-binding domain and a constant region (Fc domain) that binds to a cell surface receptor (FcR). Activation of FcRs in immune cells (lymphocytes, macrophages, and mast cells) triggers effector responses including cytokine production, phagocytosis, and degranulation. In addition to their roles in normal responses to infection or tissue injury, and in immune-related diseases, FcRs are increasingly recognized for their involvement in neurological disorders. One or more FcRs are expressed in microglia, astrocytes, oligodendrocytes, and neurons. Aberrant activation of FcRs in such neural cells may contribute to the pathogenesis of major neurodegenerative conditions including Alzheimer's disease, Parkinson's disease, ischemic stroke, and multiple sclerosis. On the other hand, FcRs may play beneficial roles in counteracting pathological processes; for e.g., FcRs may facilitate removal of amyloid peptides from the brain and so protect against Alzheimer's disease. Knowledge of the functions of FcRs in the nervous system in health and disease is leading to novel preventative and therapeutic strategies for stroke, Alzheimer's disease, and other neurological disorders.

Neuronal death in Alzheimer's disease and therapeutic opportunities

Alzheimer’s disease (AD) is an age-related neurodegenerative disease that affects approximately 24 million people worldwide. A number of different risk factors have been implicated in AD; however, neuritic (amyloid) plaques are considered as one of the defining risk factors and pathological hallmarks of the disease. In the past decade, enormous efforts have been devoted to understand the genetics and molecular pathogenesis leading to neuronal death in AD, which has been transferred into extensive experimental approaches aimed at reversing disease progression. Modern medicine is facing an increasing number of treatments available for vascular and neurodegenerative brain diseases, but no causal or neuroprotective treatment has yet been established. Almost all neurological conditions are characterized by progressive neuronal dysfunction, which, regardless of the pathogenetic mechanism, finally leads to neuronal death. The particular emphasis of this review is on risk factors and mechanisms resulting in neuronal loss in AD and current and prospective opportunities for therapeutic interventions. This review discusses these issues with a view to inspiring the development of new agents that could be useful for the treatment of AD.

A randomized controlled study on effects of ibuprofen on cognitive progression of Alzheimer's disease

BACKGROUND AND AIMS

Epidemiological studies have examined the association between the use of non-steroidal anti-inflammatory drugs (NSAIDs) and the risk of Alzheimer's disease (AD). Recently, a variety of experimental studies indicates that a subset of NSAIDs, such as ibuprofen or flurbiprofen, also have Abeta-lowering properties in both AD transgenic mice and cell cultures of peripheral, glial and neuronal origin. In this trial, we evaluated whether the non-selective NSAID ibuprofen slows disease progression in patients with mild to moderate AD.

METHODS

This was a 12-month multicenter, randomized, double-blind, placebo-controlled, parallel group trial. Participants with mild-moderate AD (Mini-Mental State Examination score >15, <26; Clinical Dementia Rating= 0.5-1), 65 years or older, with reliable caregivers, were recruited between April 2003 and September 2004. Seven AD Outpatient Treatment Centers screened 530 patients, 132 of whom were enrolled. Intervention consisted of 400 mg ibuprofen twice a day or placebo, together with 20 mg once a day of esomeprazol, or placebo. The primary measure was any one-year change in the Alzheimer Disease Assessment Scale- Cognitive (ADAS-Cog) subscale score. Secondary measures included changes in MMSE, CDR, Basic and Instrumental Activities of Daily Living scales, and Neuropsychiatric Inventory (NPI).

RESULTS

Fifty-one patients (77%) in the ibuprofen vs 46 (70%) in the placebo group completed the protocol (p>0.20). In intention-to- treat analysis, ADAS-Cog score worsening was similar in the two groups (p=0.951, treatment difference= 0.1, CI -2.7; 2.9). No differences were found for any secondary outcomes. In a subsample of genotyped patients, ApoE epsilon4 carriers treated with ibuprofen (n=27) were the only group without significant cognitive decline.

CONCLUSIONS

Ibuprofen, if used for relatively short periods of time and although well tolerated thanks to gastroprotection, does not seem to be effective in tertiary prevention of mild-moderate AD. Our results suggest the need to examine whether differences in the response to NSAIDs exist, based on ApoE epsilon4 carrier status.

Novel strategies for Alzheimer's disease treatment

Considerable progress has been made in recent years towards better understanding the pathogenesis of Alzheimer's disease (AD), a dementing neurodegenerative disorder that affects > 10 million individuals in the US and Europe combined. Recent studies suggest that alterations in the processing of amyloid precursor protein (APP), resulting in the accumulation of amyloid-beta protein (Abeta) and the formation of oligomers leads to synaptic damage and neurodegeneration. Therefore, strategies for treatment development have been focused on reducing Abeta accumulation using, among other approaches, antiaggregation molecules, regulators of the APP proteolysis and processing, reducing APP production (e.g., small-interfering RNA), and increasing Abeta clearance with antibodies, apolipoprotein E and Abeta-degrading enzymes (e.g., neprilysin). The main focus of this review is on novel treatments for AD with a special emphasis on delivering neuroprotective and antiamyloidogenic molecules by gene therapy and by promoting neurogenesis.

NSAIDs for the chemoprevention of Alzheimer's disease

Epidemiologic and laboratory studies suggest that non-steroidal anti-inflammatory drug (NSAID) use reduces the risk of Alzheimer's disease (AD). Initial reports in the early 1990's indicated that a history of arthritis, a presumed surrogate of NSAID use, was associated with a lower risk of AD. [1] These reports were followed by epidemiologic studies in which NSAID use was assessed directly and the majority of these reports confirmed the inverse association with risk for AD. [2, 3] Postmortem studies in humans [4], studies in animal models of AD [5, 6], and in vitro studies [7, 8] generally support the notion that NSAIDs can reduce the deleterious inflammation which surrounds amyloid beta (Abeta) plaques in the AD brain. In addition, some studies conducted in vitro and in rodents point to a subgroup of NSAIDs that may work by inhibiting amyloidogenic APP metabolism rather than through traditional anti-inflammatory mechanisms. [9-11] This novel property of NSAIDs is currently being explored in epidemiologic studies. Results from randomized clinical trials of NSAIDs and established AD and one trial on secondary prevention have not been promising and there have been no prevention trials completed. The feasibility of using NSAIDs as a chemopreventive agent in AD is discussed.

Medications and diet: protective factors for AD?

In the past decade, studies of Alzheimer disease risk and medication exposures, supplement intake, and dietary factors have grown in number. Typically identified in case-control and cross-sectional studies, many of these exposures have also been replicated in prospective studies. These observational studies have provided the foundation for the development of several prevention trials. This brief review focuses on exposures that have been identified in multiple studies. Observational studies of medications suggesting protection for Alzheimer disease include estrogen hormonal therapy, nonsteroidal anti-inflammatory drugs, and cholesterol-lowering statins. Evidence regarding dietary and supplemental intake of vitamins E, C, and folate, and studies of alcohol and wine intake are also reviewed. At present, there is insufficient evidence to make public health recommendations, but these studies can provide potentially important clues and new avenues for clinical and laboratory research.

NSAIDs and Alzheimer disease: epidemiological, animal model and clinical studies

This review reports correlations between four independent fields related to inflammation and Alzheimer disease: fundamental pathology, epidemiology, transgenic animal studies and clinical trials. Activated microglia, along with a spectrum of inflammatory mediators, have been identified in association with the lesions of Alzheimer disease (AD), suggesting that antiinflammatory agents such as NSAIDs should protect against the disease. In multiple epidemiological investigations testing this hypothesis, a significant risk reduction, or a trend towards such a reduction has been observed in long term as opposed to short term users of traditional NSAIDs. In studies where such NSAIDs have been administered to AD transgenic mice, a dose dependent reduction in pathology was observed. The selective C0X-2 inhibitors were ineffective. Results of clinical investigations have so far been disappointing but have nevertheless correlated with fundamental pathological findings and with transgenic mouse results. Four clinical trials using selective COX-2 inhibitors failed which is in keeping with the animal results and is consistent with pathological findings demonstrating that COX-1 and not COX-2 is the appropriate target in activated human microglia. A low dose trial of the traditional NSAID naproxen also failed, but pilot trials using therapeutically established doses of indomethacin and diclofenac/misoprostol showed promise. Further clinical investigations with relatively high doses of traditional NSAIDs might be warranted, although significant side effects should be anticipated.

Current Pharmacotherapy for Alzheimer's Disease

Alzheimer's disease (AD) is an age-related neurodegenerative disease that affects approximately 4.5 million people in the United States. The mainstays of current pharmacotherapy for AD are compounds aimed at increasing the levels of acetylcholine in the brain, thereby facilitating cholinergic neurotransmission through inhibition of the cholinesterases. These drugs, known as acetylcholinesterase inhibitors (AChEIs), were first approved by the U.S. Food and Drug Administration (FDA) in 1995 based on clinical trials showing modest symptomatic benefit on cognitive, behavioral, and global measures. In 2004 the FDA approved memantine, an NMDA antagonist, for treating dementia symptoms in moderate to severe AD cases. In clinical practice, memantine may be co-administered with an AChEI, although neither drug individually or in combination affects the underlying pathophysiology of dementia. Dementia in AD results from progressive synaptic loss and neuronal death. As knowledge of the mechanisms responsible for neurodegeneration in AD increases, it is anticipated that neuroprotective drugs to slow or prevent neuronal dysfunction and death will be developed to complement current symptomatic treatments.

Treatments for Alzheimer Disease

As our population ages, the incidence and prevalence of Alzheimer disease (AD) will increase dramatically. A number of therapies have been investigated for the treatment and prevention of AD. Clinicians should be prepared to provide evidence-based answers to inquiries regarding AD treatment. There is insufficient evidence to recommend ginkgo biloba, estrogen, statins, or nonsteroidal anti-inflammatory drugs for the prevention or treatment of AD. The use of vitamin E is supported by a single randomized controlled trial, while data on other antioxidants is mixed. There is good evidence that cholinesterase inhibitors and memantine are modestly effective in the treatment of AD. Cholinesterase inhibitors appear to be effective throughout the spectrum of AD, while memantine, alone or in combination with cholinesterase inhibitors, is effective in late stage disease. There is insufficient evidence to suggest superiority of one cholinesterase over another.

Nonsteroidal anti-inflammatory drug use and Alzheimer's disease risk: the MIRAGE Study

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAID) use may protect against Alzheimer's disease (AD) risk. We sought examine the association between NSAID use and risk of AD, and potential effect modification by APOE-epsilon4 carrier status and ethnicity.

METHODS

The MIRAGE Study is a multi-center family study of genetic and environmental risk factors for AD. Subjects comprised 691 AD patients (probands) and 973 family members enrolled at 15 research centers between 1996 and 2002. The primary independent and dependent variables were prior NSAID use and AD case status, respectively. We stratified the dataset in order to evaluate whether the association between NSAID use and AD was similar in APOE-epsilon4 carriers and non-carriers. Ethnicity was similarly examined as an effect modifier.

RESULTS

NSAID use was less frequent in cases compared to controls in the overall sample (adjusted OR = 0.64; 95% CI = 0.38-1.05). The benefit of NSAID use appeared more pronounced among APOE-epsilon4 carriers (adjusted OR = 0.49; 95% CI = 0.24-0.98) compared to non-carriers, although this association was not statistically significant. The pattern of association was similar in Caucasian and African Americans.

CONCLUSIONS

NSAID use is inversely associated with AD and may be modified by APOE genotype. Prospective studies and clinical trials of sufficient power to detect effect modification by APOE-epsilon4 carrier status are needed.

Nonsteroidal anti-inflammatory drugs for the prevention of Alzheimer's disease: a systematic review

OBJECTIVE

Alzheimer's disease, the most prevalent dementia, is a prominent source of chronic illness in the elderly. Laboratory evidence suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) might prevent the onset of Alzheimer's disease. Since the early 1990s numerous observational epidemiological studies have also investigated this possibility. The purpose of this meta-analysis is to summarize and evaluate available evidence regarding exposure to nonaspirin NSAIDs and risk of Alzheimer's disease using meta-analyses of published studies.

METHODS

A systematic search was conducted using Medline, Biological Abstracts, and the Cochrane Library for publications 1960 onwards. All cross-sectional, retrospective, or prospective observational studies of Alzheimer's disease in relation to NSAID exposure were included in the analysis. At least 2 of 4 independent reviewers characterized each study by source of data and design, including method of classifying exposure and outcome, and evaluated the studies for eligibility. Discrepancies were resolved by consensus of all 4 reviewers.

RESULTS

Of 38 publications, 11 met the qualitative criteria for inclusion in the meta-analysis. For the 3 case-control and 4 cross-sectional studies, the combined risk estimate for development of Alzheimer's disease was 0.51 (95% Cl=0.40-0.66) for NSAID exposure. In the prospective studies, the estimate was 0.74 (95% Cl=0.62-0.89) for 4 studies reporting lifetime NSAID exposure and it was 0.42 (95% Cl=0.26-0.66) for the 3 studies reporting a duration of use of 2 or more years.

CONCLUSIONS

Based on analysis of prospective and nonprospective studies, NSAID exposure was associated with decreased risk of Alzheimer's disease. An issue that requires further exploration in future trials or observational studies is the temporal relationship between NSAID exposure and protection against Alzheimer's disease.

Peroxidase Activity of Cyclooxygenase-2 (COX-2) Cross-links β-Amyloid (Aβ) and Generates Aβ-COX-2 Hetero-oligomers That Are Increased in Alzheimer's Disease

Oxidative stress is associated with the neuropathology of Alzheimer's disease. We have previously shown that human Abeta has the ability to reduce Fe(III) and Cu(II) and produce hydrogen peroxide coupled with these metals, which is correlated with toxicity against primary neuronal cells. Cyclooxygenase (COX)-2 expression is linked to the progression and severity of pathology in AD. COX is a heme-containing enzyme that produces prostaglandins, and the enzyme also possesses peroxidase activity. Here we investigated the possibility of direct interaction between human Abeta and COX-2 being mediated by the peroxidase activity. Human Abeta formed dimers when it was reacted with COX-2 and hydrogen peroxide. Moreover, the peptide formed a cross-linked complex directly with COX-2. Such cross-linking was not observed with rat Abeta, and the sole tyrosine residue specific for human Abeta might therefore be the site of cross-linking. Similar complexes of Abeta and COX-2 were detected in post-mortem brain samples in greater amounts in AD tissue than in age-matched controls. COX-2-mediated cross-linking may inhibit Abeta catabolism and possibly generate toxic intracellular forms of oligomeric Abeta.

Alzheimer’s Disease and Vascular Dementia

This chapter explores the frequency with which dementing illnesses occur in populations, their distributions by personal characteristics, and what is known about their causes and potential protective factors. The primary focus is on the most common forms of dementia: Alzheimer's disease and vascular dementia. The chapter summarizes clinical and pathologic features of Alzheimer's disease and vascular dementia, and highlights recent theories of how risk factors affect brain reserve. With the evolution of the epidemiology of dementia from case-control studies to prospective cohort studies has come a new set of methodological challenges. These include identification of representative populations, enhancing subject participation and retention in studies, the need to include institutionalized as well as community-dwelling populations, the non-standardized use of cognitive tests to screen for dementia, and the complexities of the diagnostic process itself. Finally, the chapter summarizes risk and protective factors for disease expression, including cardiovascular risk factors, lifestyle factors, and factors that affect brain reserve.

Nonsteroidal anti-inflammatory drug use and the risk for Alzheimer's disease: dissecting the epidemiological evidence

Inflammation is hypothesised to contribute to the genesis of pathology causing or contributing to Alzheimer's disease (AD). As a part of the immune response in the brain, the prostaglandin pathway is induced; this pathway is the target for NSAIDs, the most widely used anti-inflammatory medication. There are many epidemiological studies, which are reviewed here, suggesting NSAIDs reduce the risk for AD. The most recent of these studies suggest NSAIDs should be taken for at least 2 years. There are little data in humans about whether one type of NSAID is more effective than another. To date, randomised, double-blind, clinical trials in patients with AD have been negative. There is one prevention trial that will yield valuable information about the efficacy of NSAIDs in slowing down the progression of, or preventing, AD. At present, no recommendations can be made concerning the when, what, who and for how long a person should take an NSAID to reduce his or her risk for AD.