End-stage Alzheimer's Disease Research Articles

Quantitative proteomics of tau and Aβ in detergent fractions from Alzheimer's disease brains.

The two hallmarks of Alzheimer's disease (AD) are amyloid-β (Aβ) plaques and neurofibrillary tangles marked by phosphorylated tau. Increasing evidence suggests that aggregating Aβ drives tau accumulation, a process that involves synaptic degeneration leading to cognitive impairment. Conversely, there is a realization that non-fibrillar (oligomeric) forms of Aβ mediate toxicity in AD. Fibrillar (filamentous) aggregates of proteins across the spectrum of the primary and secondary tauopathies were the focus of recent structural studies with a filament structure-based nosologic classification, but less emphasis was given to non-filamentous co-aggregates of insoluble proteins in the fractions derived from post-mortem human brains. Here, we revisited sarkosyl-soluble and -insoluble extracts to characterize tau and Aβ species by quantitative targeted mass spectrometric proteomics, biochemical assays, and electron microscopy. AD brain sarkosyl-insoluble pellets were greatly enriched with Aβ42 at almost equimolar levels to N-terminal truncated microtubule-binding region (MTBR) isoforms of tau with multiple site-specific post-translational modifications (PTMs). MTBR R3 and R4 tau peptides were most abundant in the sarkosyl-insoluble materials with a 10-fold higher concentration than N-terminal tau peptides. This indicates that the major proportion of the enriched tau was the aggregation-prone N-terminal and proline-rich region (PRR) of truncated mixed 4R and 3R tau with more 4R than 3R isoforms. High concentration and occupancies of site-specific phosphorylation pT181 (~22%) and pT217 (~16%) (key biomarkers of AD) along with other PTMs in the PRR and MTBR indicated a regional susceptibility of PTMs in aggregated tau. Immunogold labelling revealed that tau may exist in globular non-filamentous form (N-terminal intact tau) co-localized with Aβ in the sarkosyl-insoluble pellets along with tau filaments (N-truncated MTBR tau). Our results suggest a model that Aβ and tau interact forming globular aggregates, from which filamentous tau and Aβ emerge. These characterizations contribute towards unravelling the sequence of events which lead to end-stage AD changes.

Advance Directives and Research Advance Directives

Advance Directives and Research Advance Directives

Disruption of endoplasmic reticulum-mitochondria tethering proteins in post-mortem Alzheimer's disease brain

Signaling between the endoplasmic reticulum (ER) and mitochondria regulates a number of key neuronal functions, many of which are perturbed in Alzheimer's disease. Moreover, damage to ER-mitochondria signaling is seen in cell and transgenic models of Alzheimer's disease. However, as yet there is little evidence that ER-mitochondria signaling is altered in human Alzheimer's disease brains. ER-mitochondria signaling is mediated by interactions between the integral ER protein VAPB and the outer mitochondrial membrane protein PTPIP51 which act to recruit and “tether” regions of ER to the mitochondrial surface. The VAPB-PTPIP51 tethers are now known to regulate a number of ER-mitochondria signaling functions including delivery of Ca2+from ER stores to mitochondria, mitochondrial ATP production, autophagy and synaptic activity. Here we investigate the VAPB-PTPIP51 tethers in post-mortem control and Alzheimer's disease brains. Quantification of ER-mitochondria signaling proteins by immunoblotting revealed loss of VAPB and PTPIP51 in cortex but not cerebellum at end-stage Alzheimer's disease. Proximity ligation assays were used to quantify the VAPB-PTPIP51 interaction in temporal cortex pyramidal neurons and cerebellar Purkinje cell neurons in control, Braak stage III-IV (early/mid-dementia) and Braak stage VI (severe dementia) cases. Pyramidal neurons degenerate in Alzheimer's disease whereas Purkinje cells are less affected. These studies revealed that the VAPB-PTPIP51 tethers are disrupted in Braak stage III-IV pyramidal but not Purkinje cell neurons. Thus, we identify a new pathogenic event in post-mortem Alzheimer's disease brains. The implications of our findings for Alzheimer's disease mechanisms are discussed.

The Accumulation of Tau-Immunoreactive Hippocampal Granules and Corpora Amylacea Implicates Reactive Glia in Tau Pathogenesis during Aging.

SummaryThe microtubule-associated tau protein forms pathological inclusions that accumulate in an age-dependent manner in tauopathies including Alzheimer's disease (AD). Since age is the major risk factor for AD, we examined endogenous tau species that evolve during aging in physiological and diseased conditions. In aged mouse brain, we found tau-immunoreactive clusters embedded within structures that are reminiscent of periodic acid-Schiff (PAS) granules. We showed that PAS granules harbor distinct tau species that are more prominent in 3xTg-AD mice. Epitope profiling revealed hypo-phosphorylated rather than hyper-phosphorylated tau commonly observed in tauopathies. High-resolution imaging and 3D reconstruction suggest a link between tau clusters, reactive astrocytes, and microglia, indicating that early tau accumulation may promote neuroinflammation during aging. Using postmortem human brain, we identified tau as a component of corpora amylacea (CA), age-related structures that are functionally analogous to PAS granules. Overall, our study supports neuroimmune dysfunction as a precipitating event in tau pathogenesis.

Dysregulation of histone acetylation pathways in hippocampus and frontal cortex of Alzheimer's disease patients

Memory impairment is the main feature of Alzheimer's disease (AD). Initial impairments originate in the temporal lobe area and propagate throughout the brain in a sequential manner. Epigenetic mechanisms, especially histone acetylation, regulate plasticity and memory processes. These may be dismantled during the disease. The aim of this work was to establish changes in the acetylation-associated pathway in two key brain regions affected in AD: the hippocampus and the F2 area of frontal cortex in end-stage AD patients and age-matched controls. We found that the F2 area was more affected than the hippocampus. Indeed, CREB-Binding Protein (CBP), P300/CBP-associated protein (PCAF), Histone Deacetylase 1 (HDAC1) and HDAC2 (but not HDAC3) levels were strongly decreased in F2 area of AD compared to controls patients, whereas only HDAC1 was decreased and CBP showed a downward trend in the hippocampus. At the histone level, we detected a substantial increase in total (H3 and H2B) histone levels in the frontal cortex, but these were decreased in nuclear extracts, pointing to a dysregulation in histone trafficking/catabolism in this brain region. Histone H3 acetylation levels were increased in cell nuclei mainly in the frontal cortex. These findings provide evidence for acetylation dysfunctions at the level of associated enzymes and of histones in AD brains, which may underlie transcriptional dysregulations and AD-related cognitive impairments. They further point to stronger dysregulations in the F2 area of the frontal cortex than in the hippocampus at an end-stage of the disease, suggesting a differential vulnerability and/or compensatory mechanisms efficiency towards epigenetic alterations.

Alzheimer's Disease Frontal Cortex Mitochondria Show a Loss of Individual Respiratory Proteins but Preservation of Respiratory Supercomplexes.

Alzheimer's disease (AD), the most common cause of sporadic dementia of in adults, shows increased risk of occurrence with aging and is destined to become a major sociomedical tragedy over the next few decades. Although likely complex in origin, sporadic AD is characterized by a progressive and stereotyped neuropathology with aggregated protein deposition (esp beta amyloid (BA) and hyperphosphorylated tau (P-tau)) and neuronal degeneration. To date, prevention of BA synthesis or immune-mediated removal of BA has failed to alter AD progression. Development and testing of P-tau therapeutics are a work in progress. AD brain tissues show multiple system deficits, including loss of respiratory capacity. In the present study there were no differences in mitochondrial mass between AD and CTL samples. We examined mitochondrial preparations of postmortem AD and CTL frontal cortex for relative levels of individual respiratory protein complexes by Western immunoblotting. ANOVA revealed deficiencies of all respiratory complex subunits in AD; post-ANOVA t-testing revealed significant differences in levels of subunits for complexes II, III, and V, borderline significance for subunit of complex IV, and no difference for subunit of complex I. We also examined mitochondrial extracts with blue-native gel electrophoresis combined with immunoblotting for subunits of complexes I and III to search for “respiratory supercomplexes” (RSC's). We found that levels of RSC's did not differ between AD and CTL samples. Mitochondrial preparations from end-stage AD brain tissue showed loss of individual ATP-producing respiration subunits but preservation of levels of assembled respiratory subunits into RSC's. Possible explanations include insufficient sensitivity of our method of RSC detection to find loss of individual subunits, or normal levels of RSC's in AD brain mitochondria coupled with decreased levels of nonassembled respiratory complex subunits. Disease-altering therapies of early AD could include stimulation of mitochondrial biogenesis to overcome loss of respiratory subunits.

Cerebral Amyloid Angiopathy: Similarity in African-Americans and Caucasians with Alzheimer's Disease.

Cerebral amyloid angiopathy (CAA) of the Aβ type is variably present in the brains of patients with Alzheimer's disease (AD). CAA contributes to cognitive decline and increases the risk of lobar hemorrhage; because both AD-typical dementia and lobar hemorrhage are more common in African-Americans than in Caucasians, we postulated that African-Americans with AD might be particularly susceptible to CAA. To test this hypothesis, we analyzed CAA histopathologically in the large vessels and capillaries of autopsy-derived frontal, temporal, parietal, and occipital cortical samples from African-Americans (n = 18) and Caucasians (n = 19) with end-stage AD. In the combined cohort of 37 subjects, 22% of the subjects had severe CAA in large vessels, and 11% had severe CAA in capillaries. However, the prevalence and histopathologic characteristics of CAA were similar in the African-Americans and Caucasians. This conclusion was substantiated in an independent sample from the National Alzheimer's Coordinating Center database, in which the degree of CAA was comparable in 1,554 Caucasians and 68 African-Americans with end-stage AD. These findings support a growing consensus that the fundamental histopathologic features of AD are largely impartial to the race of the afflicted.

Upregulation of calpain activity precedes tau phosphorylation and loss of synaptic proteins in Alzheimer's disease brain.

Alterations in calcium homeostasis are widely reported to contribute to synaptic degeneration and neuronal loss in Alzheimer’s disease. Elevated cytosolic calcium concentrations lead to activation of the calcium-sensitive cysteine protease, calpain, which has a number of substrates known to be abnormally regulated in disease. Analysis of human brain has shown that calpain activity is elevated in AD compared to controls, and that calpain-mediated proteolysis regulates the activity of important disease-associated proteins including the tau kinases cyclin-dependent kinase 5 and glycogen kinase synthase-3. Here, we sought to investigate the likely temporal association between these changes during the development of sporadic AD using Braak staged post-mortem brain. Quantification of protein amounts in these tissues showed increased activity of calpain-1 from Braak stage III onwards in comparison to controls, extending previous findings that calpain-1 is upregulated at end-stage disease, and suggesting that activation of calcium-sensitive signalling pathways are sustained from early stages of disease development. Increases in calpain-1 activity were associated with elevated activity of the endogenous calpain inhibitor, calpastatin, itself a known calpain substrate. Activation of the tau kinases, glycogen-kinase synthase-3 and cyclin-dependent kinase 5 were also found to occur in Braak stage II-III brain, and these preceded global elevations in tau phosphorylation and the loss of post-synaptic markers. In addition, we identified transient increases in total amyloid precursor protein and pre-synaptic markers in Braak stage II-III brain, that were lost by end stage Alzheimer's disease, that may be indicative of endogenous compensatory responses to the initial stages of neurodegeneration. These findings provide insight into the molecular events that underpin the progression of Alzheimer's disease, and further highlight the rationale for investigating novel treatment strategies that are based on preventing abnormal calcium homeostasis or blocking increases in the activity of calpain or important calpain substrates.Electronic supplementary materialThe online version of this article (doi:10.1186/s40478-016-0299-2) contains supplementary material, which is available to authorized users.

Immunohistochemical analysis of ubiquilin‐1 in the human hippocampus: Association with neurofibrillary tangle pathology

This post mortem immunohistochemical study examined the localization and distribution of ubiquilin-1 (UBL), a shuttle protein which interacts with ubiquitin and the proteasome, in the hippocampus from Alzheimer's disease (AD) dementia cases, and age-matched cases without dementia. In Braak stages 0-I-II cases, UBL immunoreactivity was detected in a dense fiber network in the neuropil, and in the cell cytoplasm and nucleoplasm of neurons in Cornu Ammonis (CA) fields and dentate gyrus granular neurons. In Braak stages III-IV and V-VI cases, UBL immunoreactivity was reduced in the neuropil and in the cytoplasm of the majority of CA1 neurons; some CA1 pyramidal neurons and the majority of CA2/3 pyramidal, CA4 multipolar, and dentate granular neurons had markedly increased UBL immunoreactivity in the nucleoplasm. Dual immunofluorescence analysis of UBL and antibody clone AT8 revealed co-localization most frequently in CA1 pyramidal neurons in Braak stage III-IV and V-VI cases. Further processing using the pan-amyloid marker X-34 revealed prominent UBL/X-34 dual labeling of extracellular NFT confined to the CA1/subiculum in Braak stage V-VI cases. Our results demonstrate that in AD hippocampus, early NFT changes are associated with neuronal up-regulation of UBL in nucleoplasm, or its translocation from the cytoplasm to the nucleus. The perseverance of UBL changes in CA2/3, CA4 and dentate gyrus, generally considered as more resistant to NFT pathology, but not in the CA1, may mark a compensatory, potentially protective response to increased tau phosphorylation in hippocampal neurons; the failure of such a response may contribute to neuronal degeneration in end-stage AD.

Altered synapses and gliotransmission in Alzheimer's disease and AD model mice

Amyloid-β (Aβ) plaque accumulation in Alzheimer's disease (AD) is associated with glutamatergic synapse loss, but less is known about its effect on inhibitory synapses. Here, we demonstrate that vesicular γ-aminobutyric acid (GABA) transporter (VGAT) presynaptic bouton density is unaffected in human preclinical and end-stage AD and in APP/PS1 transgenic (TG) mice. Conversely, excitatory vesicular glutamate transporter 1 (VGlut1) boutons are significantly reduced in end-stage AD cases and less reduced in preclinical AD cases and TGs. Aged TGs also show reduced protein levels of VGlut1 and synaptophysin but not VGAT or glutamate decarboxylase (GAD). These findings indicate that GABAergic synapses are preserved in human AD and mouse TGs. Synaptosomes isolated from plaque-rich TG cortex had significantly higher GAD activity than those from plaque-free cerebellum or the cortex of wild-type littermates. Using tissue fractionation, this increased activity was localized to glial synaptosomes, suggesting that Aβ plaques stimulate increased astrocyte GABA synthesis.

Modulation of autophagy as a therapeutic target for Alzheimer’s disease

Macroautophagy (autophagy) is a conserved cellular pathway that regulates the degradation of long-lived proteins, protein aggregates, and cellular organelles. Autophagy is essential for maintaining neuronal homeostasis; however, neuronal autophagic efficiency decreases with age. Therefore, aging is one of the greatest risk factors for development of Alzheimer's disease (AD), a slowly progressing form of neurodegeneration that develops over the course of 10-20 years prior to the onset of overt clinical symptoms. AD is defined neuropathologically by the presence of extracellular aggregates of the amyloidogenic protein amyloid-β (Aβ) and intracellular accumulation of the microtubule-associated protein tau. At end-stage Alzheimer's disease, abnormal autophagic pathology has been reported in human brain and in multiple mouse models of AD, suggesting that an intimate association may exist between neuronal autophagy stasis and Alzheimer's-related pathology. Here, we highlight recent evidence that the autophagic pathway plays a role in both the generation and clearance of the pathogenic Aβ protein and its precursors. The primary focus of this review is to examine the compelling research that highlights the autophagic pathway as a therapeutic target for AD and to discuss the therapeutic space around autophagy-regulating programs for AD. Finally, we propose that programs targeting autophagy regulation for AD ought to consider prophylactic or early stage intervention trials based on evidence against druggability of this pathway in late-stage disease.

Neurites containing the neurofilament-triplet proteins are selectively vulnerable to cytoskeletal pathology in Alzheimer’s disease and transgenic mouse models

Amyloid-β plaque accumulation in Alzheimer’s disease (AD) is associated with dystrophic neurite (DN) formation and synapse loss in principal neurons, but interneuron pathology is less clearly characterized. We compared the responses of neuronal processes immunoreactive for either neurofilament triplet (NF+) or calretinin (CR+) to fibrillar amyloid (Aβ) plaques in human end-stage and preclinical AD, as well as in APP/PS1 and Tg2576 transgenic mouse AD models. Neurites traversing the Aβ plaque core, edge, or periphery, defined as 50, 100, and 150% of the plaque diameter, respectively, in human AD and transgenic mouse tissue were compared to age-matched human and wild-type mouse controls. The proportion of NF+ neurites exhibiting dystrophic morphology (DN) was significantly larger than the proportion of dystrophic CR+ neurites in both human AD and transgenic mice (p < 0.01). Additionally, the number of NF+, but not CR+, DNs, correlated with Aβ plaque size. We conclude that CR+ interneurons appear to be more resistant than NF+ neurons to AD-mediated cytoskeletal pathology.

Rivastigmine Dermal Patch Solves Eating Problems in an Individual with Advanced Alzheimer's Disease

To the Editor: Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder and a leading cause of dementia in elderly adults.1 In 2003, AD was the fifth leading cause of death in individuals aged 65 and older in the United States. The best current estimates indicate that median survival after the onset of symptoms of dementia ranges from 3 to 6 years, shorter than previously estimated.2 Swallowing dysfunction with or without aspiration pneumonia is a major cause of morbidity and mortality in individuals with end-stage AD.3, 4 Herein is reported an individual with advanced AD with swallowing problems and recurrent pneumonias who was successfully treated with a rivastigmine transdermal patch. An 81-year-old woman was diagnosed with AD in 2005, manifesting as gradually progressive short-term memory loss, with a sharper decline during the past 3 years despite vigorous treatment with donepezil. Magnetic resonance imaging revealed brain atrophy, especially in the hippocampus. She had repeated episodes of aspiration pneumonia, malnutrition, dehydration, falls and femoral neck fracture, and sarcopenia. In February 2011, she was hospitalized for recurrent aspiration pneumonia and unresponsiveness. On admission, she was diagnosed as having AD according to the Functional Assessment Staging Scale, spending the entire day in a wheelchair, speaking only several words, and requiring complete support for eating and toileting. She was successfully treated using intravenous antibiotics and hydration. After pneumonia treatment, her oral intake was poor, and she occasionally refused to eat. She was taking just one or two spoonfuls of food or some juice. A bedside swallowing evaluation revealed mild oral dysphagia with delayed swallowing latency (4.2 ± 0.2 seconds).3, 4 Although a mechanically altered diet or nutritional supplements were ordered, her weight declined from 42 to 35 kg, and she developed a pressure ulcer on her hip over the next 3 months. It took a long time to hand feed and deliver oral medications, but her son did not agree to placement of a long-term feeding tube. In June 2011, she was discharged home to be cared for by her son. Her family physician and nurses provided intravenous hydration three times a week. In October 2011, her family physician decided to use a rivastigmine transdermal patch (Rivastach patch) instead of donepezil, and she was titrated from an initial dose (4.5 mg in a 2.5-cm2 patch per day) to a maintenance dose (18 mg in a 10-cm2 patch per day) by 2.5 cm2 at 4-week intervals over 16 weeks. At a dose of 9 mg (5 cm2) per day, her oral intake improved dramatically, and she gained weight. A bedside test revealed that her swallowing function had improved and that the swallowing latency had shortened (3.1 ± 0.3 seconds).3, 4 Her unresponsiveness was partially resolved, and the pressure ulcer resolved. Her clinical condition has been maintained under treatment with rivastigmine patch until now (May 2012). AD is characterized by progressive cholinergic failure with an extensive loss of cholinergic neurons.5 It has previously been shown that cholinergic neurons might be involved in the regulation of normal swallowing function,6 indicating that cholinergic dysfunction might impair swallowing reflex in individuals with advanced AD.5, 6 Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) can regulate the action of acetylcholine in the human brain, and BuChE is capable of compensating for low AChE activity.7, 8 Thus BuChE may become more important as AD progresses, and there is growing evidence that BuChE, as well as AChE, is a clinically relevant treatment target in AD.7, 8 Rivastigmine is the first approved transdermal patch for individuals with AD and has a dual inhibitory action of AChE and BuChE.7, 8 A clinical study demonstrated that rivastigmine dose-dependently inhibited BuChE activity.7 Rivastigmine might therefore improve swallowing function by slowing the degradation of acetylcholine in the cholinergic nervous system in individuals with advanced AD. In addition to a better tolerability profile than oral rivastigmine, transdermal delivery may allow better delivery for individuals with AD with swallowing disorders. Rivastigmine transdermal patch may enable individuals with advanced AD with eating problems take meals orally. Conflict of Interest: Takashi Ohrui is employed at the Division of Geriatric Pharmacotherapy, Tohoku University, which receives research funding support from Ono Pharmaceutical Company, Japan. Ono Pharmaceutical Company manufactures a rivastigmine dermal patch. Author Contributions: Uwano C, Suzuki M, Aikawa T, Ebihara T, Une K, Tomita N, Kosaka Y, Furukawa K, Arai H, and Ohrui T: Acquisition of subjects and data. Uwano C and Ohrui T: Analysis and interpretation of data and preparation of manuscript. Sponsor's Role: None.

Providing Quality Palliative Care in End-Stage Alzheimer Disease

Providing quality palliative care is a daunting task profoundly impacted by diminished patient capacity at the end of life. Alzheimer disease (AD) is a disorder that erases our memories and is projected to increase dramatically for decades to come. By the time the patients with AD reach the end stage of the disease, the ability of patients to provide pertinent subjective complaints of pain and discomfort would have vanished. Historical perspectives of palliative care, exploration of the AD process, ethical issues, and crucial clinical considerations are provided to improve the understanding of disease progression and quality of care for patients with end-stage AD.

Threshold-Independent Meta-Analysis of Alzheimer`s Disease Transcriptomes shows Progressive Changes in Hippocampal Functions, Epigenetics and microRNA Regulation

End-stage Alzheimer's disease (AD) involves drastic modifications in neuronal molecular and cellular processes, but little is known about the dynamics of these modifications during disease initiation and progression. Here, we report meta-analysis of 100 publicly available Microarray datasets using threshold-independent analysis. We found that different patients react to AD progression by variable single transcript alterations which however lead to similar changes in functional gene groups. Stratification by patients' cognitive deterioration pre`sented hippocampal-specific mRNA alterations which involved progressively changed gene categories and indicate changes in epigenetic state and microRNA profiles. In addition, datasets from laser-captured neurofibrillary tangles-free hippocampal neurons and transcript classification by cell types identified many of these changes in neurons. Intriguingly, we discovered that early-onset decline in alternative splicing, protein folding and transport transcripts occur concurrently with decreases in synaptic transmission, whereas at later stages these changes progressed into enhanced oxidative stress and inflammation. Our findings open new venues for identifying novel targets for intervention with AD progression.

Rac1b Increases with Progressive Tau Pathology within Cholinergic Nucleus Basalis Neurons in Alzheimer's Disease

Cholinergic basal forebrain (CBF) nucleus basalis (NB) neurons display neurofibrillary tangles (NFTs) during Alzheimer's disease (AD) progression, yet the mechanisms underlying this selective vulnerability are currently unclear. Rac1, a member of the Rho family of GTPases, may interact with the proapoptotic pan-neurotrophin receptor p75(NTR) to induce neuronal cytoskeletal abnormalities in AD NB neurons. Herein, we examined the expression of Rac1b, a constitutively active splice variant of Rac1, in NB cholinergic neurons during AD progression. CBF tissues harvested from people who died with a clinical diagnosis of no cognitive impairment (NCI), mild cognitive impairment, or AD were immunolabeled for both p75(NTR) and Rac1b. Rac1b appeared as cytoplasmic diffuse granules, loosely aggregated filaments, or compact spheres in p75(NTR)-positive NB neurons. Although Rac1b colocalized with tau cytoskeletal markers, the percentage of p75(NTR)-immunoreactive neurons expressing Rac1b was significantly increased only in AD compared with both mild cognitive impairment and NCI. Furthermore, single-cell gene expression profiling with custom-designed microarrays showed down-regulation of caveolin 2, GNB4, and lipase A in AD Rac1b-positive/p75(NTR)-labeled NB neurons compared with Rac1b-negative/p75(NTR)-positive perikarya in NCI. These proteins are involved in Rac1 pathway/cell cycle progression and lipid metabolism. These data suggest that Rac1b expression acts as a modulator or transducer of various signaling pathways that lead to NFT formation and membrane dysfunction in a subgroup of CBF NB neurons in AD.

Neurological diseases and pain

Chronic pain is a frequent component of many neurological disorders, affecting 20-40% of patients for many primary neurological diseases. These diseases result from a wide range of pathophysiologies including traumatic injury to the central nervous system, neurodegeneration and neuroinflammation, and exploring the aetiology of pain in these disorders is an opportunity to achieve new insight into pain processing. Whether pain originates in the central or peripheral nervous system, it frequently becomes centralized through maladaptive responses within the central nervous system that can profoundly alter brain systems and thereby behaviour (e.g. depression). Chronic pain should thus be considered a brain disease in which alterations in neural networks affect multiple aspects of brain function, structure and chemistry. The study and treatment of this disease is greatly complicated by the lack of objective measures for either the symptoms or the underlying mechanisms of chronic pain. In pain associated with neurological disease, it is sometimes difficult to obtain even a subjective evaluation of pain, as is the case for patients in a vegetative state or end-stage Alzheimer's disease. It is critical that neurologists become more involved in chronic pain treatment and research (already significant in the fields of migraine and peripheral neuropathies). To achieve this goal, greater efforts are needed to enhance training for neurologists in pain treatment and promote greater interest in the field. This review describes examples of pain in different neurological diseases including primary neurological pain conditions, discusses the therapeutic potential of brain-targeted therapies and highlights the need for objective measures of pain.

End-of-life care for persons with advanced Alzheimer disease: design and baseline data from the ALFINE study.

Alzheimer disease (AD) is the most common cause of dementia. Most affected individuals survive to an advanced stage of dementia, which is under-recognized as a terminal illness. Our objectives were to better understand the clinical trajectory of advanced AD and to identify the palliative care needs of these patients. This was an observational prospective study of AD patients in severe stage of disease included after a hospitalization in geriatric wards. They were followed up every three months during 2 years. At each visit, interviews provided data regarding: pain (Elderly Pain Caring Assessment scale), pressure ulcers, eating patterns, daily medications and use of health services. This paper describes the design of the ALFINE study and the characteristics of the recruited cohort. 112 patients were recruited (mean age: 84.03 + 6.96) years; 76.79% were women. Mean time since diagnosis of AD was 5.28 years. Pressure ulcers were observed in 42 patients. Pain assessment with the EPCA showed a mean score of 8.58. One third of patients with an EPCA score of more than 7 (median) had no analgesics. More than half of patients had been treated with antibiotics during the three months before inclusion in the study and 33 patients were still receiving antibiotics at inclusion. Two third of patients had been hospitalized in the month before inclusion. End-of-life care for individuals with end-stage AD is increasingly important because of the rising number of patients with this disease. Health care systems and clinicians should make efforts to ameliorate the suffering of patients and their caregivers.

Drug delivery strategies for Alzheimer's disease treatment

Introduction: Current Alzheimer's disease (AD) therapy is based on the administration of the drugs donepezil, galantamine, rivastigmine and memantine. Until disease-modifying therapies become available, further research is needed to develop new drug delivery strategies to ensure ease of administration and treatment persistence.Areas covered: In addition to the conventional oral formulations, a variety of drug delivery strategies applied to the treatment of AD are reviewed in this paper, with a focus on strategies leading to simplified dosage regimens and to providing new pharmacological tools. Alternatives include extended release, orally disintegrating or sublingual formulations, intranasal or short- and long-acting intramuscular or transdermal forms, and nanotechnology-based delivery systems.Expert opinion: The advent of new research on molecular mechanisms of AD pathogenesis has outlined new strategies for therapeutic intervention; these include the stimulation of α-secretase cleavage, the inhibition of γ-secretase activity, the use of non-steroidal anti-inflammatory drugs, neuroprotection based on antioxidant therapy, the use of estrogens, NO synthetase inhibitors, and natural agents such as polyphenols. Unfortunately, these compounds might not help patients with end stage AD, but might hopefully slow or stop the disease process in its early stage. Nanotechnologies may prove to be a promising contribution in future AD drug delivery strategies, in particular drug carrier nano- or microsystems, which can limit the side effects of anti-Alzheimer drugs.

Abnormal post‐translational and extracellular processing of brevican in plaque‐bearing mice over‐expressing APPsw

Aggregation of amyloid-beta (Abeta) in the forebrain of Alzheimer's disease (AD) subjects may disturb the molecular organization of the extracellular microenvironment that modulates neural and synaptic plasticity. Proteoglycans are major components of this extracellular environment. To test the hypothesis that Abeta, or another amyloid precursor protein (APP) dependent mechanism modifies the accumulation and/or turnover of extracellular proteoglycans, we examined whether the expression and processing of brevican, an abundant extracellular, chondroitin sulfate (CS)-bearing proteoglycan, were altered in brains of Abeta-depositing transgenic mice (APPsw - APP gene bearing the Swedish mutation) as a model of AD. The molecular size of CS chains attached to brevican was smaller in hippocampal tissue from APPsw mice bearing Abeta deposits compared to non-transgenic mice, likely because of changes in the CS chains. Also, the abundance of the major proteolytic fragment of brevican was markedly diminished in extracts from several telencephalic regions of APPsw mice compared to non-transgenic mice, yet these immunoreactive fragments appeared to accumulate adjacent to the plaque edge. These results suggest that Abeta or APP exert inhibitory effects on proteolytic cleavage mechanisms responsible for synthesis and turnover of proteoglycans. As proteoglycans stabilize synaptic structure and inhibit molecular plasticity, defective brevican processing observed in Abeta-bearing mice and potentially end-stage human AD, may contribute to deficient neural plasticity.