Risk factors for Alzheimer's disease: role of multiple antioxidants, non-steroidal anti-inflammatory and cholinergic agents alone or in combination in prevention and treatment

Casticin ameliorates scopolamine-induced cognitive dysfunction in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The fruit of Vitex rotundifolia L. (Verbenaceae) has been used in traditional medicine as sedative or analgesic agent for headache. Recent population-based cohort studies have shown that headache including migraines is a risk factor for dementia. Thus, the fruit of V. rotundifolia may be useful for treating cognitive dysfunction observed in dementia.

AIM OF THE STUDY

We had previously found that the ethanolic extract of the fruit of V. rotundifolia ameliorated cognitive dysfunction and isolated casticin as an active compound. In the present study, we studied the effect of casticin on a mouse model of cognitive impairment induced by scopolamine.

MATERIALS AND METHODS

Mice were treated with the ethanolic extract of the fruit of V. rotundifolia (EEVR; 30, 100 or 300 mg/kg, p.o.) or casticin (0.3, 1 or 3 mg/kg, p.o.). We examined the effect of casticin or EEVR using the passive avoidance test, the Morris water maze test and the novel object recognition test. Scopolamine (1 mg/kg, i.p.) was used to induce cognitive impairment by blocking cholinergic neurotransmitter system. We investigated the effects of casticin on acetylcholinesterase (AchE) activity and the phosphorylation levels of extracellular signal-regulated kinase (ERK), cAMP response element binding protein (CREB), and the expression levels of brain-derived neurotrophic factor (BDNF).

RESULTS

EEVR (100 and 300 mg/kg, p.o.) significantly ameliorated the latency in the passive avoidance test, and casticin (1 and 3 mg/kg, p.o.) also significantly improved the latency in the passive avoidance test, novel object preference in the novel object recognition test, and swimming time in the target quadrant of the Morris water maze test. Casticin also decreased AChE activity in ex vivo analysis and increased the phosphorylation levels of memory-related signaling molecules, such as ERK, CREB and BDNF in the cortex.

CONCLUSION

These results suggest that casticin ameliorates cholinergic blockade-induced cognitive impairment, in part, through the inhibition of AChE and the activation of the ERK-CREB-BDNF signaling pathway. Taken together, the results suggest that casticin may be useful for treating the cognitive dysfunction observed during cholinergic impairment.

An evaluation of hydromethylthionine as a treatment option for Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is a major cause of morbidity worldwide and its prevalence is expected to rise. Previous studies involving compounds that target the accumulation of amyloid β protein have been unsuccessful, renewing interest in therapies directed against intracellular deposits of tau proteins. Derived from methylene blue, hydromethylthionine is a tau aggregation inhibitor that recently emerged as a promising disease-modifying treatment for AD.

AREAS COVERED

Herein, the authors cover the chemistry, pharmacodynamics and pharmacokinetics of hydromethylthionine and its oxidized form methylthionine chloride (MTC) that was first studied, as well as clinical efficacy and safety of hydromethylthionine in the treatment of mild to moderate AD.

EXPERT OPINION

Randomized clinical trials with hydromethylthionine failed to show any impact of the doses used on the disease course. Data analysis from a non-randomized cohort showed that a smaller dose of the drug previously thought to be ineffective and used as placebo, prescribed as monotherapy rather than as add-on to AD approved symptomatic therapies may slow cognitive decline. This finding was further confirmed by a pharmacokinetic analysis study showing a dose/response relationship with doses around 16 mg daily. Future trials need to study the pharmacological properties of hydromethylthionine and ascertain the optimal safe and effective dose to be used.

MCR-ALS analysis of IR spectroscopy and XRD for the investigation of ibuprofen - nicotinamide cocrystal formation

To improve aqueous solubility, a poorly water-soluble active ingredient is classically combined with a conformer to form cocrystals. Hot melt extrusion is one preparation method for the formation of cocrystal solids. The aim of our study was to determine the optimal temperature conditions for the formation of ibuprofen and nicotinamide cocrystals using real-time infrared (IR) and X-ray diffraction (XRD) measurements. IR spectra and XRD patterns were subjected to multivariate curve resolution alternating least squares (MCR-ALS) analysis and decomposed into several components. Each component was descriptive of a specific step in the formation of the cocrystal. Cocrystal formation was followed by a separation phase between amorphous ibuprofen and crystalline nicotinamide. Our results suggest that, when using the hot melt exclusion method, careful consideration should be made towards optimizing processing temperatures in order to prevent amorphization and promote control over the process of cocrystal formation.

Synthesis and metabolism of methylglyoxal, S-D-lactoylglutathione and D-lactate in cancer and Alzheimer's disease. Exploring the crossroad of eternal youth and premature aging

Both cancer and Alzheimer's disease (AD) are emerging as metabolic diseases in which aberrant/dysregulated glucose metabolism and bioenergetics occur, and play a key role in disease progression. Interestingly, an enhancement of glucose uptake, glycolysis and pentose phosphate pathway occurs in both cancer cells and amyloid-β-resistant neurons in the early phase of AD. However, this metabolic shift has its adverse effects. One of them is the increase in methylglyoxal production, a physiological cytotoxic by-product of glucose catabolism. Methylglyoxal is mainly detoxified via cytosolic glyoxalase route comprising glyoxalase 1 and glyoxalase 2 with the production of S-D-lactoylglutathione and D-lactate as intermediate and end-product, respectively. Due to the existence of mitochondrial carriers and intramitochondrial glyoxalase 2 and D-lactate dehydrogenase, the transport and metabolism of both S-D-lactoylglutathione and D-lactate in mitochondria can contribute to methylglyoxal elimination, cellular antioxidant power and energy production. In this review, it is supposed that the different ability of cancer cells and AD neurons to metabolize methylglyoxal, S-D-lactoylglutathione and D-lactate scores cell fate, therefore being at the very crossroad of the "eternal youth" of cancer and the "premature death" of AD neurons. Understanding of these processes would help to elaborate novel metabolism-based therapies for cancer and AD treatment.

Differential diagnosis of Alzheimer's disease using spectrochemical analysis of blood

The progressive aging of the world's population makes a higher prevalence of neurodegenerative diseases inevitable. The necessity for an accurate, but at the same time, inexpensive and minimally invasive, diagnostic test is urgently required, not only to confirm the presence of the disease but also to discriminate between different types of dementia to provide the appropriate management and treatment. In this study, attenuated total reflection FTIR (ATR-FTIR) spectroscopy combined with chemometric techniques were used to analyze blood plasma samples from our cohort. Blood samples are easily collected by conventional venepuncture, permitting repeated measurements from the same individuals to monitor their progression throughout the years or evaluate any tested drugs. We included 549 individuals: 347 with various neurodegenerative diseases and 202 age-matched healthy individuals. Alzheimer's disease (AD; n = 164) was identified with 70% sensitivity and specificity, which after the incorporation of apolipoprotein ε4 genotype (APOE ε4) information, increased to 86% when individuals carried one or two alleles of ε4, and to 72% sensitivity and 77% specificity when individuals did not carry ε4 alleles. Early AD cases (n = 14) were identified with 80% sensitivity and 74% specificity. Segregation of AD from dementia with Lewy bodies (DLB; n = 34) was achieved with 90% sensitivity and specificity. Other neurodegenerative diseases, such as frontotemporal dementia (FTD; n = 30), Parkinson's disease (PD; n = 32), and progressive supranuclear palsy (PSP; n = 31), were included in our cohort for diagnostic purposes. Our method allows for both rapid and robust diagnosis of neurodegeneration and segregation between different dementias.

Pterostilbene ameliorates intracerebroventricular streptozotocin induced memory decline in rats

There is strong evidence that mitochondrial dysfunction mediated oxidative stress results in aging and energy metabolism deficits thus playing a prime role in pathogenesis of Alzheimer's disease, neuronal death and cognitive dysfunction. Evidences accrued in empirical studies suggest the antioxidant, anticancer and anti-inflammatory activities of the phytochemical pterostilbene (PTS). PTS also exhibits favourable pharmacokinetic attributes compared to other stilbenes. Hence, in the present study, we explored the neuroprotective role of PTS in ameliorating the intracerebroventricular administered streptozotocin (STZ) induced memory decline in rats. PTS at doses of 10, 30 and 50 mg/kg, was administered orally to STZ administered Sprague-Dawley (SD) rats. The learning and memory tests, Morris water maze test and novel object recognition test were performed which revealed improved cognition on PTS treatment. Further, there was an overall improvement in brain antioxidant parameters like elevated catalase and superoxide dismutase activities, GSH levels, lowered levels of nitrites, lipid peroxides and carbonylated proteins. There was improved cholinergic transmission as evident by decreased acetylcholinesterase activities. The action of ATPases (Na+ K+, Ca2+ and Mg2+) indicating the maintenance of cell membrane potential was also augmented. mRNA expression of battery of genes involved in cellular mitochondrial biogenesis and inflammation showed variations which extrapolate to hike in mitochondrial biogenesis and abated inflammation. The histological findings corroborated the effective role of PTS in countering STZ induced structural aberrations in brain.

Oxidative Stress in Alzheimer's Disease: Should We Keep Trying Antioxidant Therapies?

The risk of chronic diseases such as Alzheimer's disease is growing as a result of the continuous increasing average life span of the world population, a syndrome characterized by the presence of intraneural neurofibrillary tangles and senile plaques composed mainly by beta-amyloid protein, changes that may cause a number of progressive disorders in the elderly, causing, in its most advanced stage, difficulty in performing normal daily activities, among other manifestations. Therefore, it is important to understand the underlying pathogenic mechanisms of this syndrome. Nevertheless, despite intensive effort to access the physiopathological pathways of the disease, it remains poorly understood. In that context, some hypotheses have arisen, including the recent oxidative stress hypothesis, theory supported by the involvement of oxidative stress in aging, and the vulnerability of neurons to oxidative attack. In the present revision, oxidative changes and redox mechanisms in Alzheimer's disease will be further stressed, as well as the grounds for antioxidant supplementation as adjuvant therapy for the disease will be addressed.

Methylene blue upregulates Nrf2/ARE genes and prevents tau-related neurotoxicity

Methylene blue (MB, methylthioninium chloride) is a phenothiazine that crosses the blood brain barrier and acts as a redox cycler. Among its beneficial properties are its abilities to act as an antioxidant, to reduce tau protein aggregation and to improve energy metabolism. These actions are of particular interest for the treatment of neurodegenerative diseases with tau protein aggregates known as tauopathies. The present study examined the effects of MB in the P301S mouse model of tauopathy. Both 4 mg/kg MB (low dose) and 40 mg/kg MB (high dose) were administered in the diet ad libitum from 1 to 10 months of age. We assessed behavior, tau pathology, oxidative damage, inflammation and numbers of mitochondria. MB improved the behavioral abnormalities and reduced tau pathology, inflammation and oxidative damage in the P301S mice. These beneficial effects were associated with increased expression of genes regulated by NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE), which play an important role in antioxidant defenses, preventing protein aggregation, and reducing inflammation. The activation of Nrf2/ARE genes is neuroprotective in other transgenic mouse models of neurodegenerative diseases and it appears to be an important mediator of the neuroprotective effects of MB in P301S mice. Moreover, we used Nrf2 knock out fibroblasts to show that the upregulation of Nrf2/ARE genes by MB is Nrf2 dependent and not due to secondary effects of the compound. These findings provide further evidence that MB has important neuroprotective effects that may be beneficial in the treatment of human neurodegenerative diseases with tau pathology.

Reducing mitochondrial decay with mitochondrial nutrients to delay and treat cognitive dysfunction, Alzheimer's disease, and Parkinson's disease

Mitochondrial decay due to oxidative damage is a contributor to brain aging and age-related neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). One type of mitochondrial decay is oxidative modification of key mitochondrial enzymes. Enzyme dysfunction, that is due to poor binding of substrates and coenzymes may be ameliorated by supplementing adequate levels of substrates or coenzyme precursors. Such supplementation with mitochondrial nutrients (mt-nutrients) may be useful to prevent or delay mitochondrial decay, thus prevent or treat AD and PD. In the present review, we survey the literature to identify mt-nutrients that can (1) protect mitochondrial enzymes and/or stimulate enzyme activity by elevating levels of substrates and cofactors; (2) induce phase-2 enzymes to enhance antioxidant defenses; (3) scavenge free radicals and prevent oxidant production in mitochondria, and (4) repair mitochondrial membrane. Then, we discuss the relationships among mt-nutrient deficiency, mitochondrial decay, and cognitive dysfunction, and summarize available evidence suggesting an effect of mt-nutrient supplementation on AD and PD. It appears that greater effects might be obtained by longer-term administration of combinations of mt-nutrients. Thus, optimal doses of combinations of mt-nutrients to delay and repair mitochondrial decay could be a strategy for preventing and treating cognitive dysfunction, including AD and PD.

Vascular inflammatory, oxidative and protease-based processes: implications for neuronal cell death in Alzheimer's disease

A substantial literature demonstrates activation of inflammatory processes in the Alzheimer's disease (AD) brain and an association between inflammation and oxidative stress. We have shown that brain microvessels from AD patients express high levels of inflammatory proteins and that these proteins evoke release of the neurotoxic protease thrombin from brain endothelial cells. The objective of this study was to determine the effects of inflammatory proteins on brain endothelial cell reactive oxygen species generation, protease release and cell apoptosis. Also, the effects of inflammatory proteins on neuronal reactive oxygen species generation, injury and apoptosis were assessed. Treatment of cultured brain endothelial cells with inflammatory proteins (LPS, IL-1beta, IL-6, IFN-gamma, TNF-alpha) resulted in a significant increase (p < 0.01) in intracellular levels of reactive oxygen species by 1 h. Inflammatory proteins also caused release of tissue plasminogen activator and increased apoptosis by 24 h in these cells. In cultured neurons, inflammatory proteins caused an increase in reactive oxygen species, membrane fluidity, and apoptosis by 24 h, as detected by fluorescent microscopy. Taken together, these data support the hypothesis that vascular inflammatory, oxidative and protease-based processes contribute to neuronal cell death, and suggest that therapies targeted at these mediators and processes could be effective in AD.

Genetic testing for early-onset Alzheimer disease

The availability of testing for identified risk genes for Alzheimer disease (AD) in patients with clinically probable AD or their at-risk family members raises important questions for the neurologist. Because the potential benefits and risks of testing vary for each patient, physicians need to evaluate whether it is appropriate on a case-by-case basis. This article outlines the testing decision process and serves as a guide to assist clinicians with associated counseling and result disclosure. Because genetic testing is relatively new and preventive and therapeutic options for AD remain limited, it is important to remain sensitive to and understand the specific challenges associated with obtaining these tests in the routine clinical setting.

Biomarkers in Alzheimer's disease: a review

Alzheimer's disease is the most common form of dementia affecting millions of individuals worldwide. It is currently diagnosed only via clinical assessments and confirmed by postmortem brain pathology. The development of validated biomarkers for Alzheimer's disease is essential to improve diagnosis and accelerate the development of new therapies. Biochemical and neuroimaging markers could facilitate diagnosis, predict AD progression from a pre-AD state of mild cognitive impairment (MCI), and be used to monitor efficacies of disease-modifying therapies. Cerebrospinal fluid (CSF) levels of Aβ40, Aβ42, total tau, and phosphorylated tau have diagnostic values in AD. Measurements of the above CSF markers in combination are useful in predicting the risk of progression from MCI to AD. New potential biomarkers are emerging, and CSF or plasma marker profiles may eventually become part of the clinician's toolkit for accurate AD diagnosis and management. These biomarkers along with clinical assessment, neuropsychological testing, and neuroimaging could achieve a much higher diagnostic accuracy for AD and related disorders in the future.

Recent advances in the treatment of neurodegenerative diseases based on GSH delivery systems

Neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease(AD), are a group of pathologies characterized by a progressive and specific loss of certain brain cell populations. Oxidative stress, mitochondrial dysfunction, and apoptosis play interrelated roles in these disorders. It is well documented that free radical oxidative damage, particularly on neuronal lipids, proteins, DNA, and RNA, is extensive in PD and AD brains. Moreover, alterations of glutathione (GSH) metabolism in brain have been implicated in oxidative stress and neurodegenerative diseases. As a consequence, the reduced GSH levels observed in these pathologies have stimulated a number of researchers to find new potential approaches for maintaining or restoring GSH levels. Unfortunately, GSH delivery to the central nervous system (CNS) is limited due to a poor stability and low bioavailability. Medicinal-chemistry- and technology-based approaches are commonly used to improve physicochemical, biopharmaceutical, and drug delivery properties of therapeutic agents. This paper will focus primarily on these approaches used in order to replenish intracellular GSH levels, which are reduced in neurodegenerative diseases. Here, we discuss the beneficial properties of these approaches and their potential implications for the future treatment of patients suffering from neurodegenerative diseases, and more specifically from PD and AD.

Simultaneously improving the mechanical properties, dissolution performance, and hygroscopicity of ibuprofen and flurbiprofen by cocrystallization with nicotinamide

PURPOSE

To be fully exploitable in both formulation and manufacturing, a drug cocrystal needs to demonstrate simultaneous improvement of multiple key pharmaceutical properties over the pure drug crystal. The present work was aimed at investigating such feasibility with two model profen-nicotinamide cocrystals.

METHODS

Phase pure 1:1 ibuprofen-nicotinamide and flurbiprofen-nicotinamide cocrystals were prepared from solutions through rapid solvent removal using rotary evaporation,and characterized by DSC, PXRD, FTIR, phase solubility measurements, equilibrium moisture sorption analysis, dissolution testing and tabletability analysis.

RESULTS

Temperature-composition phase diagrams constructed from DSC data for each profen and nicotinamide crystal revealed the characteristic melting point of the 1:1 cocrystal as well as the eutectic temperatures and compositions. Both cocrystals exhibited higher intrinsic dissolution rates than the corresponding profens. The cocrystals also sorbed less moisture and displayed considerably better tabletability than the individual profens and nicotinamide.

CONCLUSIONS

Phase behaviors of 1:1 profen-nicotinamide cocrystal systems were delineated by constructing their temperature-composition phase diagrams. Cocrystallization with nicotinamide can simultaneously improve tableting behavior, hygroscopicity, and dissolution performance of ibuprofen and flurbiprofen. This could pave the way for further development of such cocrystal systems into consistent, stable, efficacious and readily manufacturable drug products.

ICV STZ induced impairment in memory and neuronal mitochondrial function: A protective role of nicotinic receptor

The present study was planned to evaluate the cholinergic influence on mitochondrial activity and neurodegeneration associated with impaired memory in intracerebroventricular (ICV) streptozotocin (STZ) treated rats. STZ (3mg/kg), administered ICV twice with an interval of 48h between the two doses, showed significant impairment in spatial memory tested by water maze test 14 days after first dose without altering blood glucose level and locomotor activity. Animals were sacrificed on 21st day of ICV administration. STZ significantly increased malondialdehyde (MDA), reactive oxygen species (ROS), Ca(2+) ion influx, caspase-3 activity and decreased glutathione (GSH) level. Acetylcholinesterase inhibitors tacrine and donepezil (5mg/kg, PO) pretreatment significantly prevented STZ induced memory deficit, oxidative stress, Ca(2+) influx and caspase-3 activity. Carbachol, a muscarinic cholinergic agonist (0.01mg/kg, SC) did not show any significant effect on ROS generation, Ca(2+) ion influx and caspase-3 activity. While nicotinic cholinergic agonist, nicotine, significantly attenuated ICV STZ induced mitochondrial dysfunction and caspase-3 activity. The results indicate that instead of muscarinic receptors nicotinic receptors may be involved in neuroprotection by maintaining mitochondrial functions.

Abnormalities in the tricarboxylic acid (TCA) cycle in the brains of schizophrenia patients

Images of brain metabolism and measurements of activities of components of the electron transport chain support earlier studies that suggest that brain glucose oxidation is inherently abnormal in a significant proportion of persons with schizophrenia. Therefore, we measured the activities of enzymes of the tricarboxylic (TCA) cycle in dorsolateral-prefrontal-cortex from schizophrenia patients (N=13) and non-psychiatric disease controls (N=13): the pyruvate dehydrogenase complex (PDHC), citrate synthase (CS), aconitase, isocitrate dehydrogenase (ICDH), the alpha-ketoglutarate dehydrogenase complex (KGDHC), succinate thiokinase (STH), succinate dehydrogenase (SDH), fumarase and malate dehydrogenase (MDH). Activities of aconitase (18.4%, p<0.05), KGDHC (26%) and STH (28.2%, p<0.05), enzymes in the first half of the TCA cycle, were lower, but SDH (18.3%, p<0.05) and MDH (34%, p<0.005), enzymes in the second half, were higher than controls. PDHC, CS, ICDH and fumarase activities were unchanged. There were no significant correlations between enzymes of TCA cycle and cognitive function, age or choline acetyl transferase activity, except for aconitase activity which decreased slightly with age (r=0.55, p=003). The increased activities of dehydrogenases in the second half of the TCA cycle may reflect a compensatory response to reduced activities of enzymes in the first half. Such alterations in the components of TCA cycle are adequate to alter the rate of brain metabolism. These results are consistent with the imaging studies of hypometabolism in schizophrenia. They suggest that deficiencies in mitochondrial enzymes can be associated with mental disease that takes the form of schizophrenia.

The effect of dietary soy isoflavones before and after ovariectomy on hippocampal protein markers of mitochondrial bioenergetics and antioxidant activity in female monkeys

Estrogen therapy can promote cognitive function if initiated within a 'critical window' during the menopausal transition. However, in the absence of a progestogen, estrogens increase endometrial cancer risk which has spurred research into developing estrogenic alternatives that have the beneficial effects of estrogen but which are clinically safer. Soy protein is rich in isoflavones, which are a class of potential estrogenic alternatives. We sought to determine the effects of two diets, one with casein-lactalbumin as the main protein source and the other with soy protein containing isoflavones, on protein markers of hippocampal bioenergetic capacity in adult female cynomolgus macaques (Macaca fascicularis). Further, we assessed the effects of dietary soy isoflavones before or after ovariectomy. Animals receiving soy diet premenopausally then casein/lactalbumin post-ovariectomy had higher relative hippocampal content of glycolytic enzymes glyceraldehyde 3-phosphate dehydrogenase and pyruvate dehydrogenase subunit e1α. Post-ovariectomy consumption of soy was associated with higher succinate dehydrogenase α levels and lower levels of isocitrate dehydrogenase, both proteins involved in the tricarboxylic acid cycle, significantly decreased expression of the antioxidant enzyme peroxiredoxin-V, and a non-significant trend towards decreased manganese superoxide dismutase expression. None of the diet paradigms significantly affected expression levels of oxidative phosphorylation enzyme complexes, or of mitochondrial fission and fusion proteins. Together, these data suggest that long-term soy diet produces minimal effects on hippocampal expression of proteins involved in bioenergetics, but that switching between a diet containing primarily animal protein and one containing soy isoflavones before and after menopause may result in complex effects on brain chemistry.

Antioxidant micronutrient impact on hearing disorders: concept, rationale, and evidence

PURPOSE

Although auditory disorders are complex conditions, device-related modalities dominate current treatment. However, dysfunction from the central cortex to the inner ear apparatus is increasingly thought to be related to biochemical pathway abnormalities and to free radical-induced oxidative damage and chronic inflammation. Therefore, considering appropriate biologic therapy as an adjunct to standard care against these damaging factors may provide rational expansion of treatment options for otolaryngologists and audiologists.

METHODS

This review outlines the biologic concepts related to some auditory and vestibular conditions and details the current rationale for utilizing antioxidants for a spectrum of hearing disorders. The strategy is based on the authors' collective experience in antioxidant science and supported with published research, pilot animal data and preliminary clinical observations.

RESULTS

A comprehensive micronutrient approach was developed to exploit these pathways, and demonstrated safety and efficacy against oxidative damage and inflammation and clinically relevant neuroprotection. Cooperative research with Department of Defense institutions used prospective, randomized designs to show (1) reduction in oxidative damage measured in plasma and urine over six months, (2) protection against oxidative damage during 12 weeks of intense military training, (3) protection against inflammation after total body blast exposure (rodents), (4) strong neuroprotection against chemically-induced Parkinson's disease (rodents), (5) nerve VIII function improvement after concussive head injury in military personnel, and (6) tinnitus improvement in majority of patients after 90-day evaluation.

CONCLUSION

This systematic review of biologic strategies against hearing disorders combined with new animal and human observations may provide a rational basis for expanding current practice paradigms.

Prevention of neurodegenerative damage to the brain in rats in experimental Alzheimer's disease by adaptation to hypoxia

We report here studies addressing the possibility of preventing neurodegenerative changes in the brain using adaptation to periodic hypoxia in rats with experimental Alzheimer's disease induced by administration of the neurotoxic peptide fragment of beta-amyloid (Ab) into the basal magnocellular nucleus. Adaptation to periodic hypoxia was performed in a barochamber (4000 m, 4 h per day, 14 days). The following results were obtained 15 days after administration of Ab. 1. Adaptation to periodic hypoxia significantly blocked Ab-induced memory degradation in rats, as assessed by testing a conditioned passive avoidance reflex. 2. Adaptation to periodic hypoxia significantly restricted increases in oxidative stress, measured spectrophotometrically in the hippocampus in terms of the content of thiobarbituric acid-reactive secondary lipid peroxidation products. 3. Adaptation to periodic hypoxia completely prevented the overproduction of NO in the brains of rats with experimental Alzheimer's disease, as measured in terms of increases in tissue levels of stable NO metabolites, i.e., nitrites and nitrates. 4. The cerebral cortex of rats given Ab injections after adaptation to periodic hypoxia did not contain neurons with pathomorphological changes or dead neurons (Nissl staining), which were typical in animals with experimental Alzheimer's disease. Thus, adaptation to periodic hypoxia effectively prevented oxidative and nitrosative stress, protecting against neurodegenerative changes and protecting cognitive functions in experimental Alzheimer's disease.

Implication of complement system and its regulators in Alzheimer's disease

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. Complement proteins are integral components of amyloid plaques and cerebral vascular amyloid in Alzheimer brains. They can be found at the earliest stages of amyloid deposition and their activation coincides with the clinical expression of Alzheimer's dementia. This review emphasizes on the dual key roles of complement system and complement regulators (CRegs) in disease pathology and progression. The particular focus of this review is on currently evolving strategies for design of complement inhibitors that might aid therapy by restoring the fine balance between activated components of complement system, thus improving the cognitive performance of patients. This review discusses these issues with a view to inspiring the development of new agents that could be useful for the treatment of AD.

Antiamnesic effect of stevioside in scopolamine-treated rats

The present study was undertaken to explore the potential of stevioside in memory dysfunction of rats. Memory impairment was produced by scopolamine (0.5 mg/kg, i.p.) in animals. Morris water maze (MWM) test was employed to assess learning and memory. Brain acetylcholinestrase enzyme (AChE) activity was measured to assess the central cholinergic activity. The levels of brain thiobarbituric acid-reactive species (TBARS) and reduced glutathione (GSH) were estimated to assess the degree of oxidative stress. Scopolamine administration induced significant impairment of learning and memory in rats, as indicated by a marked decrease in MWM performance. Scopolamine administration also produced a significant enhancement of brain AChE activity and brain oxidative stress (increase in TBARS and decrease in GSH) levels. Pretreatment of stevioside (250 mg/kg dose orally) significantly reversed scopolamine-induced learning and memory deficits along with attenuation of scopolamine-induced rise in brain AChE activity and brain oxidative stress levels. It may be concluded that stevioside exerts a memory-preservative effect in cognitive deficits of rats possibly through its multiple actions.

Mitochondrial mechanisms of estrogen neuroprotection

Mitochondria have become a primary focus in our search not only for the mechanism(s) of neuronal death but also for neuroprotective drugs and therapies that can delay or prevent Alzheimer's disease and other chronic neurodegenerative conditions. This is because mitochrondria play a central role in regulating viability and death of neurons, and mitochondrial dysfunction has been shown to contribute to neuronal death seen in neurodegenerative diseases. In this article, we review the evidence for the role of mitochondria in cell death and neurodegeneration and provide evidence that estrogens have multiple effects on mitochondria that enhance or preserve mitochondrial function during pathologic circumstances such as excitotoxicity, oxidative stress, and others. As such, estrogens and novel non-hormonal analogs have come to figure prominently in our efforts to protect neurons against both acute brain injury and chronic neurodegeneration.

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.

Expression of somatostatin and somatostatin receptor subtypes in Apolipoprotein D (ApoD) knockout mouse brain: An immunohistochemical analysis

Apolipoprotein D (ApoD) is widely distributed in central and peripheral nervous system. ApoD expression has been shown to increase in several neurodegenerative and neuropsychiatric disorders, as well as during regeneration in the nervous system. Like ApoD, in the central nervous system somatostatin (SST) is widely present and functions as neurotransmitter and neuromodulator. The biological effects of SST are mediated via binding to five high-affinity G-protein coupled receptors termed SSTR1-5. Mice lacking ApoD exhibit reduced SST labeling in cortex and hippocampus and increased expression in striatum and amygdala without any noticeable changes in substantia nigra. Changes in SSTRs expressions have been described in several neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. In the present study, using SSTR1-5 receptor-specific antibodies, we mapped their distribution in wild type (wt) and ApoD knockout (ApoD(-/-)) mouse brain. SSTR1-5 expression was observed both as membrane and cytoplasmic protein and display regions and receptor specific differences between wt and ApoD(-/-) mice brains. In cortex and hippocampus, SSTR subtypes like immunoreactivity are decreased in ApoD(-/-) mice brain. Unlike cortex and hippocampus, in the striatum of ApoD(-/-) mice, projection neurons showed increased SSTR immunoreactivity, as compared to wt. Higher SSTR subtypes immunoreactivity is seen in substantia nigra pars compacta (SNpc) whereas lower in substantia nigra pars reticulata (SNpr) of ApoD(-/-) mice brains as compared to wt. Whereas, amygdala displayed SSTR subtypes changes in different nuclei of ApoD(-/-) mice in comparison to wt mice brain. Taken together, our results describe receptor and region specific changes in SST and SSTR subtypes expression in ApoD(-/-) mice brain, which may be linked to specific neurological disorders.

Estrogen actions on mitochondria--physiological and pathological implications

Estrogens are potent neuroprotective hormones and mitochondria are the site of cellular life-death decisions. As such, it is not surprising that we and others have shown that estrogens have remarkable effects on mitochondrial function. Herein we provide evidence for a primary effect of estrogens on mitochondrial function, achieved in part by the import of estrogen receptor beta (ERbeta) into the mitochondria where it mediates a number of estrogen actions on this vital organelle. ERbeta is imported into the mitochondria, through tethering to cytosolic chaperone protein and/or through direct interaction with mitochondrial import proteins. In the mitochondria, ERbeta can affect transcription of critical mitochondrial genes through the interaction with estrogen response elements (ERE) or through protein-protein interactions with mitochondrially imported transcription factors. The potent effects of estrogens on mitochondrial function, particularly during mitochondrial stress, argues for a role of estrogens in the treatment of mitochondrial defects in chronic neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD) and more acute conditions of mitochondrial compromise, like cerebral ischemia and traumatic brain injury.

Vitamin A supplementation induces a prooxidative state in the striatum and impairs locomotory and exploratory activity of adult rats

Although vitamin A has been reported to be essential to brain homeostasis, some central nervous system (CNS)-associated deleterious effects may be induced by vitamin A or by its metabolites. In this work, we investigated the effects of acute and chronic vitamin A supplementation at therapeutic (1,000 or 2,500 IU/kg/day) or excessive (4,500 or 9,000 IU/kg/day) doses on the redox state of the rat striatum. We found a 1.8- to 2.7-fold increase of lipid peroxidation in the striatum after acute or chronic supplementation (TBARS method). Therapeutic doses induced a 1.6- to 2.2-fold increase of protein carbonylation (dinitrophenylhydrazine (DNPH) derivatization). Vitamin A supplementation induced a 1.2- to 1.4-fold decrease of protein thiol content acutely and chronically. Superoxide dismutase (SOD) activity, assessed through the inhibition of epinephrine's autoxidation, was increased in a dose-dependent manner chronically. Acutely, both therapeutic and excessive vitamin A doses induced a 1.8- to 2.2-fold decrease of catalase (CAT) activity, as determined through the rate of decrease of hydrogen peroxide (H(2)O(2)). Glutathione peroxidase (GPx) activity did not change in this experimental model. Some vitamin A doses decreased the non-protein thiol content only chronically. Vitamin A supplementation decreased the striatal non-enzymatic antioxidant defenses (TRAP assay). Furthermore, our results show that vitamin A supplementation impaired the SOD/CAT ratio. Moreover, we observed a 1.6- to 2.0-fold decrease of locomotion and exploration in an open field after vitamin A supplementation. Therefore, our results suggest that vitamin A supplementation induces oxidative stress in the rat striatum and that it may be related to a metabolic impairment in such brain area.

The Effects and Mechanisms of Mitochondrial Nutrient α-Lipoic Acid on Improving Age-Associated Mitochondrial and Cognitive Dysfunction: An Overview

We have identified a group of nutrients that can directly or indirectly protect mitochondria from oxidative damage and improve mitochondrial function and named them "mitochondrial nutrients". The direct protection includes preventing the generation of oxidants, scavenging free radicals or inhibiting oxidant reactivity, and elevating cofactors of defective mitochondrial enzymes with increased Michaelis-Menten constant to stimulate enzyme activity, and also protect enzymes from further oxidation, and the indirect protection includes repairing oxidative damage by enhancing antioxidant defense systems either through activation of phase 2 enzymes or through increase in mitochondrial biogenesis. In this review, we take alpha-lipoic acid (LA) as an example of mitochondrial nutrients by summarizing the protective effects and possible mechanisms of LA and its derivatives on age-associated cognitive and mitochondrial dysfunction of the brain. LA and its derivatives improve the age-associated decline of memory, improve mitochondrial structure and function, inhibit the age-associated increase of oxidative damage, elevate the levels of antioxidants, and restore the activity of key enzymes. In addition, co-administration of LA with other mitochondrial nutrients, such as acetyl-L: -carnitine and coenzyme Q10, appears more effective in improving cognitive dysfunction and reducing oxidative mitochondrial dysfunction. Therefore, administrating mitochondrial nutrients, such as LA and its derivatives in combination with other mitochondrial nutrients to aged people and patients suffering from neurodegenerative diseases, may be an effective strategy for improving mitochondrial and cognitive dysfunction.

Mitochondrial mechanisms of estrogen neuroprotection

Oxidative stress, bioenergetic failure and mitochondrial dysfunction are all implicated in the etiology of neurodegenerative diseases such as Alzheimer's disease (AD). The mitochondrial involvement in neurodegenerative diseases reflects the regulatory role mitochondrial failure plays in both necrotic cell death and apoptosis. The potent feminizing hormone, 17 beta-estradiol (E2), is neuroprotective in a host of cell and animal models of stroke and neurodegenerative diseases. The discovery that 17alpha-estradiol, an isomer of E2, is equally as neuroprotective as E2 yet is >200-fold less active as a hormone, has permitted development of novel, more potent analogs where neuroprotection is independent of hormonal potency. Studies of structure-activity relationships and mitochondrial function have led to a mechanistic model in which these steroidal phenols intercalate into cell membranes where they block lipid peroxidation reactions, and are in turn recycled. Indeed, the parental estrogens and novel analogs stabilize mitochondria under Ca(2+) loading otherwise sufficient to collapse membrane potential. The neuroprotective and mitoprotective potencies for a series of estrogen analogs are significantly correlated, suggesting that these compounds prevent cell death in large measure by maintaining functionally intact mitochondria. This therapeutic strategy is germane not only to sudden mitochondrial failure in acute circumstances, such as during a stroke or myocardial infarction, but also to gradual mitochondrial dysfunction associated with chronic degenerative disorders such as AD.

Involvement of multitargets in paeoniflorin-induced preconditioning

Paeoniflorin (PF) is the principal component of Paeoniae radix prescribed in traditional Chinese medicine. The delayed neuroprotection induced by PF preconditioning and its underlying mechanisms were investigated in rat middle cerebral artery occlusion (MCAO) and reperfusion model. At a dosage of 20 or 40 mg/kg, PF preconditioning 48 h before MCAO followed by 24-h reperfusion significantly reduced the mortality and infarct volume and reversed the neurological deficits caused by ischemia. Likewise, the ameliorative effects on mortality, infarct size, and neurological impairment induced by MCAO emerged as well when PF was administered 24 h, 48 h, or 5 days before MCAO at the dose of 20 mg/kg. Furthermore, comparative proteomics analysis was adopted to identify the differentially expressed proteins induced by PF preconditioning itself. The relative levels of 42 proteins were altered after PF preconditioning, among which 20 were elevated and 22 reduced. In summary, A(1) receptor-regulator of G protein signaling-K(ATP) signaling, arachidonic acid cascade, nitric oxide system, markers of neuronal damage, mitochondrial damage-related molecules, and the mitogen-activated protein kinase and nuclear factor-kappaB pathway are associated with the mechanisms of PF preconditioning.

Protein ubiquitination, degradation and the proteasome in neuro-degenerative disorders: no clear evidence for a significant pathogenetic role of proteasome failure in Alzheimer disease and related disorders

It has recently been proposed that Alzheimer disease (AD) might be initiated by a molecular 'hit' into a regulatory protein, e.g. a cell surface receptor [Schmitt HP. Neuro-modulation, aminergic neuro-disinhibition and neuro-degeneration: draft of a comprehensive theory for Alzheimer disease. Med Hypoth 2005;65:1106-19]. However, other substrates, in particular intra-cellular protein complexes such as the ubiquitin/proteasome system (UPS) could as well serve as a targets for such a 'hit' which might insert a mutation or induce conformational changes resulting in functional failure of protein degradation along the ubiquitin/proteasome proteolytic pathway. It has been claimed that impairment of the large multi-catalytic protease complex, the 20S/26S proteasome, might represent a key factor in the early pathogenesis of neuro-degenerative disorders characterized by the formation of abnormal protein aggregates such as neuronal cytoplasmic or nuclear inclusion bodies and fibrillary deposits. This article aims to review critically whether current information really supports the idea that impairment of the UPS might play a significant role in the early pathogenesis of neuro-degenerative disorders, with special emphasis on AD. The data provided in favour of proteasome impairment were, as a rule, revealed in in vitro experiments which cannot be unequivocally transferred to the in vivo conditions in neuro-degeneration. The author concludes that there is yet no clear evidence of a pivotal role of proteasome failure in the early pathogenesis of AD.

Differential regulation of c-jun and CREB by acrolein and 4-hydroxynonenal

In Alzheimer's disease (AD), oxidative stress-induced lipid peroxidation leads to accumulation of unsaturated aldehydes including acrolein and 4-hydroxynonenal (4HNE) in brain. In this study, we examined the effects of these lipid peroxidation products on apoptotic pathways in cultured neurons. Acrolein and 4HNE increased the levels of active phosphorylated forms of c-jun and CREB, the transcription factors that promote apoptosis and cell survival, respectively. However, they decreased the activity of CREB-dependent BDNF promoter while they increased the activity of promoters responsive to c-jun. We hypothesized that this differential regulation could be due to competition between proapoptotic c-jun and cytoprotective CREB for CBP (CREB-binding protein), a coactivator shared by several transcription factors. In support of this hypothesis, we demonstrate that the decrease of BDNF promoter activity by acrolein and 4HNE could be restored (i) by cotransfection with CBP, (ii) by cotransfection with VP 16-CREB, a constitutively active form of CREB that does not depend on CBP for its activation, or (iii) by inhibiting JNK-mediated c-jun activation. Finally, adenoviral transduction of hippocampal neurons with VP 16-CREB resulted in significant reduction in caspase-3 activation by acrolein and 4HNE. These observations suggest that lipid peroxidation-induced differential regulation of CREB and c-jun might play a role in neurodegeneration in AD.

Prostaglandin-induced neurodegeneration is associated with increased levels of oxidative markers and reduced by a mixture of antioxidants

Prostaglandin E2 (PGE2), one product of inflammatory reactions, and PGA1, which is formed during PGE2 extraction, induce degeneration in adenosine 3',5'-cyclic monophosphate (cAMP)-induced differentiated neuroblastoma (NB) cells in culture. The mechanisms of action of PGE2 on neurodegeneration are not well understood. To investigate this, we have utilized PGA(1), which mimics the effect of PGE2 and is very stable in solution. We have assayed selected markers of oxidative stress such as heme oxygenase-1 (HO-1), catalase, glutathione peroxidase (GPx1), mitochondrial superoxide dismutase (Mn-SOD-2) and cytosolic superoxide dismutase (Cu/Zn-SOD-1). The results showed that the treatment of differentiated NB cells with PGA1 for a period of 48 hr increased the expression of HO-1 and catalase, decreased the expression of GPx1 and Mn-SOD-2, and did not change the expression of Cu/Zn-SOD-1 as measured by gene array and confirmed by real-time PCR. The protein levels of HO-1 and GPx1 increased; however, the protein level of Mn-SOD-2 decreased and the levels of catalase and Cu/Zn-SOD-1 did not change as determined by Western blot. The increases in the levels of HO-1 and GPx1 reflected an adaptive response to increased oxidative stress, whereas decrease in the level of Mn-SOD-2 may make cells more sensitive to oxidative damage. These data suggest that one of the mechanisms of action of PGA1 on neurodegeneration may involve increased oxidative stress. This was supported further by the fact that a mixture of antioxidants (alpha-tocopherol, vitamin C, selenomethionine, and reduced glutathione), but not the individual antioxidants, reduced the level of PGA1-induced degeneration in differentiated NB cells. The addition of a single antioxidant at two or four times the concentration used in the mixture was toxic.

Dementia and Alzheimer's disease in community-dwelling elders taking vitamin C and/or vitamin E

BACKGROUND

Since increased oxidative stress may impair cognition and be a risk factor for dementia, there has been interest in determining whether use of antioxidants could protect against such events.

OBJECTIVE

To determine whether supplement use of vitamins C and/or E in a community-based sample of older African American and white individuals delayed incident dementia or Alzheimer's disease (AD).

METHODS

We selected a subgroup from the Duke Established Populations for Epidemiologic Studies of the Elderly, a longitudinal study of community-representative persons aged 65-105 years living in 5 adjacent counties in North Carolina, and followed them for dementia (1986-1987 through June 2000). Information gathered during in-home interviews included sociodemographic characteristics, health status, health service use, and vitamin use. Diagnosis of dementia and AD was based on evaluations using the clinical and neuropsychological batteries of the Consortium to Establish a Registry for Alzheimer's Disease, with final determination by consensus agreement of specialists using Diagnostic and Statistical Manual of Mental Disorders, third revision, and National Institute for Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders criteria.

RESULTS

Of 616 persons initially dementia-free (mean age 73 y; 62% female; 62% African American), 141 developed dementia, of whom 93 developed AD. Increased age and mobility problems were risk factors for dementia (only age for AD), while an increased number of outpatient visits reduced the likelihood of developing dementia. Neither use of any vitamins C and/or E (used by 8% of subjects at baseline) nor high-dose use reduced the time to dementia or AD.

CONCLUSIONS

In this community in the southeastern US where vitamin supplement use is low, use of vitamins C and/or E did not delay the incidence of dementia or AD.

A review of antioxidants and Alzheimer's disease

BACKGROUND

In this article, we review a diverse body of research and draw conclusions about the usefulness, or lack there-of, of specific antioxidants in the prevention of Alzheimer's disease (AD).

METHODS

The National Library of Medicine's database was searched for the years 1996-2004 using the search terms "Alzheimer's, anti-oxidants, antioxidants."

RESULTS

Over 300 articles were identified and 187 articles were selected for inclusion based on relevance to the topic. Agents that show promise in helping prevent AD include: 1) aged garlic extract, 2) curcumin, 3) melatonin, 4) resveratrol, 5) Ginkgo biloba extract, 6) green tea, 7) vitamin C and 8) vitamin E.

CONCLUSIONS

While the clinical value of antioxidants for the prevention of AD is often ambiguous, some can be recommended based upon: 1) epidemiological evidence, 2) known benefits for prevention of other maladies, and 3) benign nature of the substance. Long-term, prospective studies are recommended.

Rationale for using multiple antioxidants in protecting humans against low doses of ionizing radiation

Health risks of low doses of ionizing radiation (10 cGy or less) may not be accurately estimated in humans by epidemiological study or mathematical modelling because of several inherent confounding factors including environmental, dietary and biological variables that cannot be accounted for in any radio-epidemiological study. In addition, the expression of radiation-induced damage in humans not only depends upon total dose, dose rate, linear energy transfer (LET), and fractionation and protraction of total doses, but also on repair mechanisms, bystander effects, and exposure to chemical carcinogens, tumour promoters and other toxins. It also depends upon the levels of anti-carcinogenic and anti-tumour promoting agents. Low doses of ionizing radiation should not be considered insignificant with regard to increasing the incidence of somatic mutations (neoplastic and non-neoplastic diseases) and heritable mutations in humans owing to its interaction with other toxins that can enhance damage produced by irradiation. It is very prudent to continue to support the well-established radiobiological concept that no radiation dose can be considered completely safe, and that all efforts must be made to reduce both the radiation dose and biological damage, no matter how small that damage might be, without sacrificing the benefits of radiation. Based on the results of many scientific experiments, formulations containing multiple antioxidants for biological protection against radiation damage in humans can be developed, and this strategy together with the existing physical concept of radiation protection, should further reduce potential risks of low doses of ionizing radiation in humans.

Potent Inhibitory effect of flavonoids in Scutellaria baicalensis on amyloid beta protein-induced neurotoxicity

The free radical scavenging activities of two major flavonoids (baicalein and baicalin) in Scutellaria baicalensis were determined. The antioxidant capacities of baicalein and baicalin were determined by the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(*)(-) scavenging assay and showed about 110 and 70% vitamin C equivalent antioxidant capacity, respectively. Because amyloid beta (Abeta) protein is known to increase free radical production and lipid peroxidation in PC12 nerve cells, leading to apoptosis and cell death, treatment with baicalein and baicalin may result in the prevention of cellular damage by the Abeta-induced reactive oxygen species. We found that baicalein and baicalin resulted in a dose-dependent anti-Abeta toxicity by means of three different assays [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction, lactate dehydrogenase release, and trypan blue exclusion assays]. These results suggest that baicalein as well as baicalin can reduce the cytotoxicity of Abeta protein in PC12 cells, possibly by a reduction of oxidative stress, and these flavonoids may be useful in the chemoprevention of Alzheimer's disease.

Prevalence of dementia and Alzheimer's disease in elders of nursing homes and a senior center of Durango City, Mexico

BACKGROUND

Epidemiological reports about dementia and Alzheimer's disease (AD) in elderly people from developing countries are scarce. Therefore, we sought to determine the prevalences of dementia and AD in a population of nursing home residents and senior center attendees of Durango City, Mexico, and to determine whether any socio-demographic characteristics from the subjects associated with dementia or AD exist.

METHODS

One hundred and fifty-five residents of two nursing homes and 125 attendees of a senior center were examined for dementia and Alzheimer's disease. All subjects were tested by the mini-mental state examination, and those who scored twenty-four or less underwent psychiatric and neurological evaluations. Diagnosis of dementia, AD and vascular dementia (VaD) was based on the DSM-IV criteria. Socio-demographic characteristics from each participant were also obtained.

RESULTS

Residents of nursing homes found to suffer from dementia were 25 out of 155 (16.1%). Eighteen of them (11.6%) had AD, and seven (4.5%) had VaD. None of the attendees of the senior center suffered from dementia. Dementia (pooled AD and VaD cases) correlated with white ethnicity (OR = 3.2; 95%CI = 1.28-8.31), and a history of unemployment (OR = 6.46; 95%CI = 1.42-25.97), while AD correlated with journeymen occupations (OR = 4.55; 95%CI = 1.00-19.29).

CONCLUSION

Prevalence of dementia in residents of nursing homes found in this study is much lower than reported from more industrialized countries. AD was more frequent than VaD. Ethnicity and occupation showed effects on the prevalence figures. The prevalence of dementia found has implications for the optimum kind of health care that nursing homes should provide to their residents.