Dementia and Death After Stroke in Older Adults During a 10-year Follow-up: Results from a Competing Risk Model

Melatonin Inhibits Hypoxia-Induced Alzheimer's Disease Pathogenesis by Regulating the Amyloidogenic Pathway in Human Neuroblastoma Cells

Stroke and Alzheimer's disease (AD) are prevalent age-related diseases; however, the relationship between these two diseases remains unclear. In this study, we aimed to investigate the ability of melatonin, a hormone produced by the pineal gland, to alleviate the effects of ischemic stroke leading to AD by observing the pathogenesis of AD hallmarks. We utilized SH-SY5Y cells under the conditions of oxygen-glucose deprivation (OGD) and oxygen-glucose deprivation and reoxygenation (OGD/R) to establish ischemic stroke conditions. We detected that hypoxia-inducible factor-1α (HIF-1α), an indicator of ischemic stroke, was highly upregulated at both the protein and mRNA levels under OGD conditions. Melatonin significantly downregulated both HIF-1α mRNA and protein expression under OGD/R conditions. We detected the upregulation of β-site APP-cleaving enzyme 1 (BACE1) mRNA and protein expression under both OGD and OGD/R conditions, while 10 µM of melatonin attenuated these effects and inhibited beta amyloid (Aβ) production. Furthermore, we demonstrated that OGD/R conditions were able to activate the BACE1 promoter, while melatonin inhibited this effect. The present results indicate that melatonin has a significant impact on preventing the aberrant development of ischemic stroke, which can lead to the development of AD, providing new insight into the prevention of AD and potential stroke treatments.

A Look at the Etiology of Alzheimer's Disease based on the Brain Ischemia Model

Alzheimer's disease (AD) is the frequent form of dementia in the world. Despite over 100 years of research into the causes of AD, including amyloid and tau protein, the research has stalled and has not led to any conclusions. Moreover, numerous projects aimed at finding a cure for AD have also failed to achieve a breakthrough. Thus, the failure of anti-amyloid and anti-tau protein therapy to treat AD significantly influenced the way we began to think about the etiology of the disease. This situation prompted a group of researchers to focus on ischemic brain episodes, which, like AD, mostly present alterations in the hippocampus. In this context, it has been proposed that cerebral ischemic incidents may play a major role in promoting amyloid and tau protein in neurodegeneration in AD. In this review, we summarized the experimental and clinical research conducted over several years on the role of ischemic brain episodes in the development of AD. Studies have shown changes typical of AD in the course of brain neurodegeneration post-ischemia, i.e., progressive brain and hippocampal atrophy, increased amyloid production, and modification of tau protein. In the post-ischemic brain, the diffuse and senile amyloid plaques and the development of neurofibrillary tangles characteristic of AD were revealed. The above data evidently showed that after brain ischemia, there are modifications in protein folding, leading to massive neuronal death and damage to the neuronal network, which triggers dementia with the AD phenotype.

Left-truncated health insurance claims data: theoretical review and empirical application

From the inventory of the health insurer AOK in 2004, we draw a sample of a quarter million people and follow each person’s health claims continuously until 2013. Our aim is to estimate the effect of a stroke on the dementia onset probability for Germans born in the first half of the 20th century. People deceased before 2004 are randomly left-truncated, and especially their number is unknown. Filtrations, modelling the missing data, enable circumventing the unknown number of truncated persons by using a conditional likelihood. Dementia onset after 2013 is a fixed right-censoring event. For each observed health history, Jacod’s formula yields its conditional likelihood contribution. Asymptotic normality of the estimated intensities is derived, related to a sample size definition including the number of truncated people. The standard error results from the asymptotic normality and is easily computable, despite the unknown sample size. The claims data reveal that after a stroke, with time measured in years, the intensity of dementia onset increases from 0.02 to 0.07. Using the independence of the two estimated intensities, a 95% confidence interval for their difference is [0.053, 0.057]. The effect halves when we extend the analysis to an age-inhomogeneous model, but does not change further when we additionally adjust for multi-morbidity.

Post-Ischemic Brain Neurodegeneration in the Form of Alzheimer's Disease Proteinopathy: Possible Therapeutic Role of Curcumin

For thousands of years, mankind has been using plant extracts or plants themselves as medicinal herbs. Currently, there is a great deal of public interest in naturally occurring medicinal substances that are virtually non-toxic, readily available, and have an impact on well-being and health. It has been noted that dietary curcumin is one of the regulators that may positively influence changes in the brain after ischemia. Curcumin is a natural polyphenolic compound with pleiotropic biological properties. The observed death of pyramidal neurons in the CA1 region of the hippocampus and its atrophy are considered to be typical changes for post-ischemic brain neurodegeneration and for Alzheimer’s disease. Additionally, it has been shown that one of the potential mechanisms of severe neuronal death is the accumulation of neurotoxic amyloid and dysfunctional tau protein after cerebral ischemia. Post-ischemic studies of human and animal brains have shown the presence of amyloid plaques and neurofibrillary tangles. The significant therapeutic feature of curcumin is that it can affect the aging-related cellular proteins, i.e., amyloid and tau protein, preventing their aggregation and insolubility after ischemia. Curcumin also decreases the neurotoxicity of amyloid and tau protein by affecting their structure. Studies in animal models of cerebral ischemia have shown that curcumin reduces infarct volume, brain edema, blood-brain barrier permeability, apoptosis, neuroinflammation, glutamate neurotoxicity, inhibits autophagy and oxidative stress, and improves neurological and behavioral deficits. The available data suggest that curcumin may be a new therapeutic substance in both regenerative medicine and the treatment of neurodegenerative disorders such as post-ischemic neurodegeneration.

Post-Ischemic Neurodegeneration of the Hippocampus Resembling Alzheimer's Disease Proteinopathy

In this review, we summarize, inter alia, the protein and gene changes associated with Alzheimer’s disease and their role in post-ischemic hippocampal neurodegeneration. In the hippocampus, studies have revealed dysregulation of the genes for the amyloid protein precursor metabolism and tau protein that is identical in nature to Alzheimer’s disease. Data indicate that amyloid and tau protein, derived from brain tissue and blood due to increased permeability of the blood–brain barrier after ischemia, play a key role in post-ischemic neurodegeneration of the hippocampus, with concomitant development of full-blown dementia. Thus, the knowledge of new neurodegenerative mechanisms that cause neurodegeneration of the hippocampus after ischemia, resembling Alzheimer’s disease proteinopathy, will provide the most important therapeutic development goals to date.

The Many Faces of Post-Ischemic Tau Protein in Brain Neurodegeneration of the Alzheimer's Disease Type

Recent data suggest that post-ischemic brain neurodegeneration in humans and animals is associated with the modified tau protein in a manner typical of Alzheimer’s disease neuropathology. Pathological changes in the tau protein, at the gene and protein level due to cerebral ischemia, can lead to the development of Alzheimer’s disease-type neuropathology and dementia. Some studies have shown increased tau protein staining and gene expression in neurons following ischemia-reperfusion brain injury. Recent studies have found the tau protein to be associated with oxidative stress, apoptosis, autophagy, excitotoxicity, neuroinflammation, blood-brain barrier permeability, mitochondrial dysfunction, and impaired neuronal function. In this review, we discuss the interrelationship of these phenomena with post-ischemic changes in the tau protein in the brain. The tau protein may be at the intersection of many pathological mechanisms due to severe neuropathological changes in the brain following ischemia. The data indicate that an episode of cerebral ischemia activates the damage and death of neurons in the hippocampus in a tau protein-dependent manner, thus determining a novel and important mechanism for the survival and/or death of neuronal cells following ischemia. In this review, we update our understanding of proteomic and genomic changes in the tau protein in post-ischemic brain injury and present the relationship between the modified tau protein and post-ischemic neuropathology and present a positive correlation between the modified tau protein and a post-ischemic neuropathology that has characteristics of Alzheimer’s disease-type neurodegeneration.

Neuroinflammation in Post-Ischemic Neurodegeneration of the Brain: Friend, Foe, or Both?

One of the leading causes of neurological mortality, disability, and dementia worldwide is cerebral ischemia. Among the many pathological phenomena, the immune system plays an important role in the development of post-ischemic degeneration of the brain, leading to the development of neuroinflammatory changes in the brain. After cerebral ischemia, the developing neuroinflammation causes additional damage to the brain cells, but on the other hand it also plays a beneficial role in repair activities. Inflammatory mediators are sources of signals that stimulate cells in the brain and promote penetration, e.g., T lymphocytes, monocytes, platelets, macrophages, leukocytes, and neutrophils from systemic circulation to the brain ischemic area, and this phenomenon contributes to further irreversible ischemic brain damage. In this review, we focus on the issues related to the neuroinflammation that occurs in the brain tissue after ischemia, with particular emphasis on ischemic stroke and its potential treatment strategies.

Brain Ischemia as a Prelude to Alzheimer's Disease

Transient ischemic brain injury causes massive neuronal death in the hippocampus of both humans and animals. This was accompanied by progressive atrophy of the hippocampus, brain cortex, and white matter lesions. Furthermore, it has been noted that neurodegenerative processes after an episode of ischemia-reperfusion in the brain can continue well-beyond the acute stage. Rarefaction of white matter was significantly increased in animals at 2 years following ischemia. Some rats that survived 2 years after ischemia developed severe brain atrophy with dementia. The profile of post-ischemic brain neurodegeneration shares a commonality with neurodegeneration in Alzheimer's disease. Furthermore, post-ischemic brain injury is associated with the deposition of folding proteins, such as amyloid and tau protein, in the intracellular and extracellular space. Recent studies on post-ischemic brain neurodegeneration have revealed the dysregulation of Alzheimer's disease-associated genes such as amyloid protein precursor, α-secretase, β-secretase, presenilin 1, presenilin 2, and tau protein. The latest data demonstrate that Alzheimer's disease-related proteins and their genes play a key role in the development of post-ischemic brain neurodegeneration with full-blown dementia in disease types such as Alzheimer's. Ongoing interest in the study of brain ischemia has provided evidence showing that ischemia may be involved in the development of the genotype and phenotype of Alzheimer's disease, suggesting that brain ischemia can be considered as a useful model for understanding the mechanisms responsible for the initiation of Alzheimer's disease.

Myricetin as a Promising Molecule for the Treatment of Post-Ischemic Brain Neurodegeneration

The available drug therapy for post-ischemic neurodegeneration of the brain is symptomatic. This review provides an evaluation of possible dietary therapy for post-ischemic neurodegeneration with myricetin. The purpose of this review was to provide a comprehensive overview of what scientists have done regarding the benefits of myricetin in post-ischemic neurodegeneration. The data in this article contribute to a better understanding of the potential benefits of myricetin in the treatment of post-ischemic brain neurodegeneration, and inform physicians, scientists and patients, as well as their caregivers, about treatment options. Due to the pleiotropic properties of myricetin, including anti-amyloid, anti-phosphorylation of tau protein, anti-inflammatory, anti-oxidant and autophagous, as well as increasing acetylcholine, myricetin is a promising candidate for treatment after ischemia brain neurodegeneration with full-blown dementia. In this way, it may gain interest as a potential substance for the prophylaxis of the development of post-ischemic brain neurodegeneration. It is a safe substance, commercially available, inexpensive and registered as a pro-health product in the US and Europe. Taken together, the evidence available in the review on the therapeutic potential of myricetin provides helpful insight into the potential clinical utility of myricetin in treating neurodegenerative disorders with full-blown dementia. Therefore, myricetin may be a promising complementary agent in the future against the development of post-ischemic brain neurodegeneration. Indeed, there is a scientific rationale for the use of myricetin in the prevention and treatment of brain neurodegeneration caused by ischemia.

Prevalence and Incidence of Dementia in South Korea: A Nationwide Analysis of the National Health Insurance Service Senior Cohort

BACKGROUND AND PURPOSE

Dementia is rapidly becoming more common in the elderly population of South Korea, and there are regional difference in its demographics. This study investigated the trajectories in the prevalence and incidence of dementia based on the Seoul metropolitan area and other areas in South Korea using big data from the National Health Insurance Service (NHIS).

METHODS

We examined a population-based elderly cohort obtained from the NHIS Senior Cohort (NHIS-SC) data set that comprises approximately half a million recipients of medical insurance in South Korea during 2003-2015. The age-standardized prevalence and incidence of dementia as well as their trajectories from 2003 were estimated. Regional differences in these rates between Seoul metropolitan area and other areas were also analyzed.

RESULTS

The standardized prevalence of dementia per 100,000 increased significantly from 178.11 in 2003 to 5,319.01 in 2015 (p<0.001). The standardized prevalence of dementia was higher in other areas than in Seoul metropolitan area. The standardized incidence of dementia per 100,000 person-years also increased significantly, from 126.41 in 2003 to 2,218.25 in 2015 (p<0.001). The standardized incidence of dementia was similarly higher in other areas than in Seoul metropolitan area (p<0.001).

CONCLUSIONS

This study has shown that the standardized prevalence and incidence of dementia increased steadily from 2003 to 2015 in South Korea based on the NHIS-SC data set, and differed between Seoul metropolitan area and other areas.

Dysregulation of Autophagy, Mitophagy, and Apoptosis Genes in the CA3 Region of the Hippocampus in the Ischemic Model of Alzheimer's Disease in the Rat

 There is currently no knowledge about the expression profile of the autophagy (BECN1), mitophagy (BNIP3), and apoptosis (CASP3) genes in the CA3 region of the hippocampus after cerebral ischemia. In addition, it is unknown whether genes for BECN1, BNIP3, and CASP3 have any effect on the neuronal death in the CA3 area of the hippocampus due to ischemia. In this study, for the first time, we present, by means of a quantitative PCR protocol with reverse transcriptase, the expression of BECN1 and CASP3 genes in the neuronal CA3 region of the hippocampus with the co-expression of the mitochondrial BNIP3 gene, which genes are associated with Alzheimer’s disease, in the ischemic model of Alzheimer’s disease in the rat. The present study showed that after ischemia, the CASP3 gene was significantly expressed within 7–30 days, the BECN1 gene was significantly overexpressed on the thirtieth day, and the BINP3 gene was lowered below control values during post-ischemic follow-up period. The caspase-dependent neuronal death in the CA3 region of the hippocampus after ischemia is not accompanied by overexpression of the BNIP3 gene. Our data may therefore suggest a new insight into the BNIP3 gene in the regulation of neuronal mitophagy in neurodegeneration in the CA3 region of the hippocampus after ischemia. This indicates no involvement of the BNIP3 gene along with the CASP3 gene in the CA3 region of the hippocampus in delayed neuronal death after brain ischemia.

Association between dementia and depression: a retrospective study using the Korean National Health Insurance Service-National Sample Cohort database

OBJECTIVES

Dementia is common in people over the age of 65 years, with 80% of people with dementia older than 75 years. Previous studies have linked dementia to late-life depression, but the association between dementia and mid-life depression is poorly understood. Depression is a preventable and treatable medical condition, which means it is a modifiable factor that can potentially prevent or delay dementia. This study aimed to identify the association between dementia and depression within the life course.

DESIGN

A nationwide, retrospective propensity score matched cohort study associating dementia with depression. Depression diagnosed between the ages of 45 and 64 years was classified as 'mid-life' and 'late-life' if diagnosed at 65 years or older. Patients were considered to have depression when one or more International Statistical Classification of Diseases and Related Health Problems, 10th revision codes for depression were recorded as primary or secondary diagnosis.

SETTING

National Health Insurance Service-National Sample Cohort database of the National Health Insurance Service in South Korea, containing patient data from 2002 to 2013.

PARTICIPANTS

The study included 1824 and 374 852 patients in the case and control groups, respectively. A logistic regression analysis with complex sampling design was performed after adjusting for covariates, using the propensity score matching method without callipers, with a 1:1 nearest neighbour matching algorithm.

PRIMARY AND SECONDARY OUTCOME MEASURES

The association of mid-onset and late-onset depression with dementia in terms of sociodemographic characteristics, such as sex and age, within the Korean population.

RESULTS

Dementia was significantly associated with the presence of depression (OR=2.20, 95% CI=1.53-3.14); in particular, female patients with depression and patients aged 45-64 years with depression had increased odds of dementia (OR=2.65, 95% CI=1.78-3.93 and OR=2.72, 95% CI=1.41-5.24, respectively) CONCLUSION: Depression is an associated factor for dementia, especially among people aged 45-64 years (mid-life).

Participation of Amyloid and Tau Protein in Neuronal Death and Neurodegeneration after Brain Ischemia

Current evidence indicates that postischemic brain injury is associated with the accumulation of folding proteins, such as amyloid and tau protein, in the intra- and extracellular spaces of neuronal cells. In this review, we summarize protein changes associated with Alzheimer’s disease and their gene expression (amyloid protein precursor and tau protein) after brain ischemia, and their roles in the postischemic period. Recent advances in understanding the postischemic mechanisms in development of neurodegeneration have revealed dysregulation of amyloid protein precursor, α-, β- and γ-secretase and tau protein genes. Reduced expression of the α-secretase gene after brain ischemia with recirculation causes neuronal cells to be less resistant to injury. We present the latest data that Alzheimer’s disease-related proteins and their genes play a crucial role in postischemic neurodegeneration. Understanding the underlying processes of linking Alzheimer’s disease-related proteins and their genes in development of postischemic neurodegeneration will provide the most significant goals to date for therapeutic development.

Heterogeneity in brain distribution of activated microglia and astrocytes in a rat ischemic model of Alzheimer's disease after 2 years of survival

The present study was designed to follow neuroinflammation after ischemic brain injury in the long-term survival rat model. Immunohistochemistry was performed 2 years after 10 min global brain ischemia due to cardiac arrest. For the visualization of the cellular inflammatory reaction microglial marker Iba1 and astrocyte marker GFAP were used. In post-ischemic animals our study revealed significant activation of astrocytes in all tested brain regions (hippocampal CA1 and CA3 areas and dentate gyrus, motor and somatosensory cortex, striatum and thalamus), while microglial activation was only found in CA1 and CA3 areas, and the motor cortex. In the specifically sensitive brain areas microglia and astrocytes showed simultaneously significant activation, while in the resistant brain areas only astrocytes were activated. Thus, there was clear evidence of less intensive neuroinflammation in brain areas resistant to ischemia. Such neuroinflammatory processes are backed by microglia and astrocytes activity even up to 2 years after ischemia-reperfusion brain injury. Our study thus revealed a chronic effect of global cerebral ischemia on the neuroinflammatory reaction in the rat brain even 2 years after the insult.

Proteomic and Genomic Changes in Tau Protein, Which Are Associated with Alzheimer's Disease after Ischemia-Reperfusion Brain Injury

Recent evidence suggests that transient ischemia of the brain with reperfusion in humans and animals is associated with the neuronal accumulation of neurotoxic molecules associated with Alzheimer’s disease, such as all parts of the amyloid protein precursor and modified tau protein. Pathological changes in the amyloid protein precursor and tau protein at the protein and gene level due to ischemia may lead to dementia of the Alzheimer’s disease type after ischemic brain injury. Some studies have demonstrated increased tau protein immunoreactivity in neuronal cells after brain ischemia-reperfusion injury. Recent research has presented many new tau protein functions, such as neural activity control, iron export, protection of genomic DNA integrity, neurogenesis and long-term depression. This review discusses the potential mechanisms of tau protein in the brain after ischemia, including oxidative stress, apoptosis, autophagy, excitotoxicity, neurological inflammation, endothelium, angiogenesis and mitochondrial dysfunction. In addition, attention was paid to the role of tau protein in damage to the neurovascular unit. Tau protein may be at the intersection of many regulatory mechanisms in the event of major neuropathological changes in ischemic stroke. Data show that brain ischemia activates neuronal changes and death in the hippocampus in a manner dependent on tau protein, thus determining a new and important way to regulate the survival and/or death of post-ischemic neurons. Meanwhile, the association between tau protein and ischemic stroke has not been well discussed. In this review, we aim to update the knowledge about the proteomic and genomic changes in tau protein following ischemia-reperfusion injury and the connection between dysfunctional tau protein and ischemic stroke pathology. Finally we present the positive correlation between tau protein dysfunction and the development of sporadic Alzheimer’s disease type of neurodegeneration.

Substantiation for the Use of Curcumin during the Development of Neurodegeneration after Brain Ischemia

Currently available pharmacological treatment of post-ischemia-reperfusion brain injury has limited effectiveness. This review provides an assessment of the current state of neurodegeneration treatment due to ischemia-reperfusion brain injury and focuses on the role of curcumin in the diet. The purpose of this review was to provide a comprehensive overview of what was published about the benefits of curcumin influence on post-ischemic brain damage. Some data on the clinical benefits of curcumin treatment of post-ischemic brain in terms of clinical symptoms and adverse reactions have been reviewed. The data in this review contributes to a better understanding of the potential benefits of curcumin in the treatment of neurodegenerative changes after ischemia and informs scientists, clinicians, and patients, as well as their families and caregivers about the possibilities of such treatment. Due to the pleotropic properties of curcumin, including anti-amyloid, anti-tau protein hyperphosphorylation, anti-inflammatory, anti-apoptotic, and neuroprotective action, as well as increasing neuronal lifespan and promoting neurogenesis, curcumin is a promising candidate for the treatment of post-ischemic neurodegeneration with misfolded proteins accumulation. In this way, it may gain interest as a potential therapy to prevent the development of neurodegenerative changes after cerebral ischemia. In addition, it is a safe substance and inexpensive, easily accessible, and can effectively penetrate the blood–brain barrier and neuronal membranes. In conclusion, the evidence available in a review of the literature on the therapeutic potential of curcumin provides helpful insight into the potential clinical utility of curcumin in the treatment of neurological neurodegenerative diseases with misfolded proteins. Therefore, curcumin may be a promising supplementary agent against development of neurodegeneration after brain ischemia in the future. Indeed, there is a rational scientific basis for the use of curcumin for the prophylaxis and treatment of post-ischemic neurodegeneration.

Expression of the Tau Protein and Amyloid Protein Precursor Processing Genes in the CA3 Area of the Hippocampus in the Ischemic Model of Alzheimer's Disease in the Rat

Understanding the mechanisms underlying the selective susceptibility to ischemia of the CA3 region is very important to explain the neuropathology of memory loss after brain ischemia. We used a rat model to study changes in gene expression of the amyloid protein precursor and its cleaving enzymes and tau protein in the hippocampal CA3 sector, after transient 10-min global brain ischemia with survival times of 2, 7, and 30 days. The expression of the α-secretase gene was below control values at all times studied. But, the expression of the β-secretase gene was below the control values at 2-7 days after ischemia and the maximal increase in its expression was observed on day 30. Expression of the presenilin 1 gene was significantly elevated above the control values at 2-7 days after ischemia and decreased below the control values at day 30. Expression of the presenilin 2 gene showed an opposite trend to the expression of presenilin 1. Expression of the amyloid protein precursor gene after ischemia was at all times above the control values with a huge significant overexpression on day 7. Additionally, the expression of the tau protein gene was below the control values 2 days after ischemia, but the significant increase in its expression was observed on days 7-30. Data show that brain ischemia activates neuronal changes and death in the CA3 region of the hippocampus in a manner dependent on amyloid and tau protein, thus determining a new and important way to regulate the survival and/or death of ischemic neurons.

Tau Protein Dysfunction after Brain Ischemia

Brain ischemia comprises blood-brain barrier, glial, and neuronal cells. The blood–brain barrier controls permeability of different substances and the composition of the neuronal cells ‘milieu’, which is required for their physiological functioning. Recent evidence indicates that brain ischemia itself and ischemic blood-brain barrier dysfunction is associated with the accumulation of neurotoxic molecules within brain tissue, e.g., different parts of amyloid-β protein precursor and changed pathologically tau protein. All these changes due to ischemia can initiate and progress neurodegeneration of the Alzheimer’s disease-type. This review presents brain ischemia and ischemic blood-brain barrier as a trigger for tau protein alterations. Thus, we hypothesize that the changes in pattern of phosphorylation of tau protein are critical to microtubule function especially in neurons, and contribute to the neurodegeneration following brain ischemia-reperfusion episodes with Alzheimer’s disease phenotype.

Cohort Profile: National health insurance service-senior (NHIS-senior) cohort in Korea

PURPOSE

The National Health Insurance Service (NHIS)-Senior was set up to provide high-quality longitudinal data that can be used to explore various aspects of changes in the socio-economical and health status of older adults, to predict risk factors and to investigate their health outcomes.

PARTICIPANTS

The NHIS-Senior cohort, a Korean nationwide retrospective administrative data cohort, is composed of older adults aged 60 years and over in 2002. It consists of 558 147 people selected by 10% simple random sampling method from a total of 5.5 million subjects aged 60+ in the National Health Information Database. The cohort was followed up through 2015 for all subjects, except for those who were deceased.

FINDINGS TO DATE

The healthcare utilisation and admission rates were the highest for acute upper respiratory infections and influenza (75.2%). The age-standardised (defined with reference to the world standard population) mortality rate for 10 years (through 2012) was 4333 per 100 000 person-years. Malignant neoplasms were the most common cause of death in both sexes (1032.1 per 100 000 person-years for men, 376.7 per 100 000 person-years for women). A total of 34 483 individuals applied for long-term care service in 2008, of whom 17.9% were assessed as grade 1, meaning that they were completely dependent on the help of another person to live daily life.

FUTURE PLANS

The data are provided for the purposes of policy and academic research under the Act on Promotion of the Provision and Use of Public Data in Korea. The NHIS-Senior cohort data are only available for Korean researchers at the moment, but it is possible for researchers outside the country to gain access to the data by conducting a joint study with a Korean researcher. The cohort will be maintained and continuously updated by the NHIS.

Neuroprotective and Neurological/Cognitive Enhancement Effects of Curcumin after Brain Ischemia Injury with Alzheimer's Disease Phenotype

In recent years, ongoing interest in ischemic brain injury research has provided data showing that ischemic episodes are involved in the development of Alzheimer's disease-like neuropathology. Brain ischemia is the second naturally occurring neuropathology, such as Alzheimer's disease, which causes the death of neurons in the CA1 region of the hippocampus. In addition, brain ischemia was considered the most effective predictor of the development of full-blown dementia of Alzheimer's disease phenotype with a debilitating effect on the patient. Recent knowledge on the activation of Alzheimer's disease-related genes and proteins-e.g., amyloid protein precursor and tau protein-as well as brain ischemia and Alzheimer's disease neuropathology indicate that similar processes contribute to neuronal death and disintegration of brain tissue in both disorders. Although brain ischemia is one of the main causes of death in the world, there is no effective therapy to improve the structural and functional outcomes of this disorder. In this review, we consider the promising role of the protective action of curcumin after ischemic brain injury. Studies of the pharmacological properties of curcumin after brain ischemia have shown that curcumin has several therapeutic properties that include anti-excitotoxic, anti-oxidant, anti-apoptotic, anti-hyperhomocysteinemia and anti-inflammatory effects, mitochondrial protection, as well as increasing neuronal lifespan and promoting neurogenesis. In addition, curcumin also exerts anti-amyloidogenic effects and affects the brain's tau protein. These results suggest that curcumin may be able to serve as a potential preventive and therapeutic agent in neurodegenerative brain disorders.

Stroke and dementia risk: A systematic review and meta-analysis

INTRODUCTION

Stroke is an established risk factor for all-cause dementia, though meta-analyses are needed to quantify this risk.

METHODS

We searched Medline, PsycINFO, and Embase for studies assessing prevalent or incident stroke versus a no-stroke comparison group and the risk of all-cause dementia. Random effects meta-analysis was used to pool adjusted estimates across studies, and meta-regression was used to investigate potential effect modifiers.

RESULTS

We identified 36 studies of prevalent stroke (1.9 million participants) and 12 studies of incident stroke (1.3 million participants). For prevalent stroke, the pooled hazard ratio for all-cause dementia was 1.69 (95% confidence interval: 1.49-1.92; P < .00001; I2 = 87%). For incident stroke, the pooled risk ratio was 2.18 (95% confidence interval: 1.90-2.50; P < .00001; I2 = 88%). Study characteristics did not modify these associations, with the exception of sex which explained 50.2% of between-study heterogeneity for prevalent stroke.

DISCUSSION

Stroke is a strong, independent, and potentially modifiable risk factor for all-cause dementia.