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Many psychiatric and neurological disorders present deficits in both the social and cognitive domain. In this perspectives article, we provide an overview and the potential of the existence of an extensive neurobiological substrate underlying the close relationship between these two domains. By mapping the rodent brain regions involved in the social and/or cognitive domain, we show that the vast majority of brain regions involved in the cognitive domain are also involved in the social domain. The identified neuroanatomical overlap has an evolutionary basis, as complex social behavior requires cognitive skills, and aligns with the reported functional interactions of processes underlying cognitive and social performance. Based on the neuroanatomical mapping, recent (pre-)clinical findings, and the evolutionary perspective, we emphasize that the social domain requires more focus as an important treatment target and/or biomarker, especially considering the presently limited treatment strategies for these disorders.

Neutrophil gelatinase-associated lipocalin (NGAL) is an acute phase protein that has been reported as a potential marker for pre-dementia stages of Alzheimer's disease (AD). Longitudinal studies for its association with the conversion of mild cognitive impairment to AD is still lacking. This study included n = 268 study participants with subjective cognitive decline (SCD) (n = 82), mild cognitive impairment (MCI) (n = 98) and AD dementia (n = 88) at baseline and two-year follow-up clinical assessments. Serum and cerebrospinal fluid (CSF)NGAL, CSF amyloid beta(1-42), total-Tau, and phospho-Tau levels were measured with ELISA analysis. CSF NGAL levels were significantly lower in MCI participants compared to people with SCD at baseline. Lower baseline CSF NGAL levels predicted MCI converters to AD dementia vs. non-converters after 2-years follow-up. A positive correlation between CSF NGAL and amyloid beta(1-42) was found particularly in MCI participants at baseline. NGAL in CSF holds potential to be used as a predictive marker for the conversion of MCI to AD dementia and may reflect pathophysiological processes of prodromal AD neuropathology. (C) 2021 The Authors. Published by Elsevier Inc.

Chronic (neuro)inflammation plays an important role in many age-related central nervous system (CNS) diseases, including Alzheimer's disease, Parkinson's disease and vascular dementia. Inflammation also characterizes many conditions that form a risk factor for these CNS disorders, such as physical inactivity, obesity and cardiovascular disease. Lipocalin 2 (Lcn2) is an inflammatory protein shown to be involved in different age-related CNS diseases, as well as risk factor conditions thereof. Lcn2 expression is increased in the periphery and the brain in different age-related CNS diseases and also their risk factor conditions. Experimental studies indicate that Lcn2 contributes to various neuropathophysiological processes of age-related CNS diseases, including exacerbated neuroinflammation, cell death and iron dysregulation, which may negatively impact cognitive function. We hypothesize that increased Lcn2 levels as a result of age-related risk factor conditions may sensitize the brain and increase the risk to develop age-related CNS diseases. In this review we first provide a comprehensive overview of the known functions of Lcn2, and its effects in the CNS. Subsequently, this review explores Lcn2 as a potential (neuro)inflammatory link between different risk factor conditions and the development of age-related CNS disorders. Altogether, evidence convincingly indicates Lcn2 as a key constituent in ageing and age-related brain diseases.

Tumor necrosis factor-α (TNF-α) is a pleiotropic, proinflammatory cytokine related to different neurodegenerative diseases, including Alzheimer’s disease (AD). Although the linkage between increased TNF-α levels and AD is widely recognized, TNF-α–neutralizing therapies have failed to treat AD. Previous research has associated this with the antithetic functions of the two TNF receptors, TNF receptor 1, associated with inflammation and apoptosis, and TNF receptor 2 (TNFR2), associated with neuroprotection. In our study, we investigated the effects of specifically stimulating TNFR2 with a TNFR2 agonist (NewStar2) in a transgenic Aβ-overexpressing mouse model of AD by administering NewStar2 in two different ways: centrally, via implantation of osmotic pumps, or systemically by intraperitoneal injections. We found that both centrally and systemically administered NewStar2 resulted in a drastic reduction in amyloid β deposition and β-secretase 1 expression levels. Moreover, activation of TNFR2 increased microglial and astrocytic activation and promoted the uptake and degradation of Aβ. Finally, cognitive functions were also improved after NewStar2 treatment. Our results demonstrate that activation of TNFR2 mitigates Aβ-induced cognitive deficits and neuropathology in an AD mouse model and indicates that TNFR2 stimulation might be a potential treatment for AD.

Policymakers aim to move toward animal-free alternatives for scientific research and have introduced very strict regulations for animal research. We argue that, for neuroscience research, until viable and translational alternatives become available and the value of these alternatives has been proven, the use of animals should not be compromised., We would like to thank Loren Frank, UCSF, USA; Sheena Josselyn, Hospital for Sick Children, University of Toronto, Canada; Shantanu Jadhav, Brandeis University, USA; the European Animal Research Association (EARA); the Federation of European Neuroscience Societies Committee on Animals in Research (CARE); the Swiss Society for Neuroscience; the Society for Neuroscience Committee on Animals in Research (CAR); and Stichting Informatie Dierproeven (the Dutch foundation for public information on animal testing: SID) for input on and support for this article.

BACKGROUND: Myocardial infarction (MI) coinciding with depression worsens prognosis. Although Tumor Necrosis Factor alpha (TNF) is recognized to play a role in both conditions, the therapeutic potential of TNF inhibition is disappointing. TNF activates two receptors, TNFR1 and TNFR2, associated with opposite effects. Therefore, anti-inflammatory treatment with specific TNF receptor interference was compared to non-specific TNF inhibition regarding effects on heart, (neuro)inflammation, brain and behavior in mice with MI.METHODS: Male C57BL/6 mice were subjected to MI or sham surgery. One hour later, MI mice were randomized to either non-specific TNF inhibition by Enbrel, specific TNFR1 antagonist-, or specific TNFR2 agonist treatment until the end of the protocol. Control sham and MI mice received saline. Behavioral evaluation was obtained day 10-14 after surgery. Eighteen days post-surgery, cardiac function was measured and mice were sacrificed. Blood and tissue samples were collected for analyses of (neuro)inflammation.RESULTS: MI mice displayed left ventricular dysfunction, without heart failure, (neuro) inflammation or depressive-like behavior. Both receptor-specific interventions, but not Enbrel, doubled early post-MI mortality. TNFR2 agonist treatment improved left ventricular function and caused hyper-ramification of microglia, with no effect on depressive-like behavior. In contrast, TNFR1 antagonist treatment was associated with enhanced (neuro)inflammation: more plasma eosinophils and monocytes; increased plasma Lcn2 and hippocampal microglia and astrocyte activation. Moreover, increased baseline heart rate, with reduced beta-adrenergic responsiveness indicated sympathetic activation, and coincided with reduced exploratory behavior in the open field. Enbrel did not affect neuroinflammation nor behavior.CONCLUSION: Early receptor interventions, but not non-specific TNF inhibition, increased mortality. Apart from this undesired effect, the general beneficial profile after TNFR2 stimulation, rather than the unfavourable effects of TNFR1 inhibition, would render TNFR2 stimulation preferable over non-specific TNF inhibition in MI with comorbid depression. However, follow-up studies regarding optimal timing and dosing are needed.

Many psychiatric and neurological disorders present deficits in both the social and cognitive domain. In this perspectives article, we provide an overview and the potential of the existence of an extensive neurobiological substrate underlying the close relationship between these two domains. By mapping the rodent brain regions involved in the social and/or cognitive domain, we show that the vast majority of brain regions involved in the cognitive domain are also involved in the social domain. The identified neuroanatomical overlap has an evolutionary basis, as complex social behavior requires cognitive skills, and aligns with the reported functional interactions of processes underlying cognitive and social performance. Based on the neuroanatomical mapping, recent (pre-)clinical findings, and the evolutionary perspective, we emphasize that the social domain requires more focus as an important treatment target and/or biomarker, especially considering the presently limited treatment strategies for these disorders.

Toxic levels of phenylalanine in blood and brain is a characteristic of (untreated) phenylketonuria (PKU), leading to cognitive deficits in PKU mice. In addition, our recent findings showed that PKU mice (as well as PKU patients) have a disturbed sleep/wake cycle. As a consequence, sleep loss may contribute to cognitive deficits in PKU. Sleep loss has been linked to increased activation of microglia in the hippocampus. In this study, we set out to examine morphological features of the microglia population in the hippocampus of the mouse PKU model, using both the C57Bl/6 and the BTBR strain and their wild-type controls (age 5.3 ± 0.5 months; n = 16 per group, both males and females; n = 8 each). Microglial activation is reflected by retraction and thickening of the dendritic branches and an increase in cell body size of a microglial cell. Such morphological changes of microglia were studied by way of immunohistochemical staining for Iba-1, a microglia-specific calcium binding protein. We measured the number of microglia in seven subregions of the dorsal hippocampus. The level of microglial activation was determined, based on the ratio between the soma size and total cell size (soma size plus the area covered by the dendritic branches). Results showed subtle but statistical significant activation of hippocampal microglia in the C57Bl6, but not in the BTBR, PKU mice when compared with their wild-type controls. Also the total number of microglia was higher in the C57Bl/6 PKU (compared to the wild-type) mouse, but not in the BTBR PKU mouse. It is concluded that the C57Bl/6 PKU mouse has mildly higher microglia activity, which may support rather than hamper hippocampal homeostasis. The results further indicate that high levels of phenylalanine or disturbed sleep patterns do not consequently cause hippocampal microglial activation in the PKU mouse. It is currently unknown why the two PKU mouse strains show these differences in number and activation level of their hippocampal microglia, and to what extent it influences hippocampal functioning. Further scrutinizing the role of microglia functioning in the context of PKU is therefore warranted.

Background: Soluble oligomeric amyloid-β (Aβ), rather than Aβ plaques, seems to be the culprit in Alzheimer's disease (AD). Accordingly, a new concept vaccine of small cyclic peptide conjugates, selectively targeting oligomeric Aβ, has been developed.Objective: Study the therapeutic potential of this new vaccine in a mouse model for AD.Methods: J20 mice, overexpressing human amyloid precursor protein, were validated for an AD-like phenotype. Then, J20 mice were vaccinated at 2, 3, and 4 months of age and AD phenotype was evaluated at 6, 9, and 12 months of age; or at 9, 10, and 11 months with evaluation at 12 months. Effects on Aβ pathology were studied by plaque load (immunohistochemistry; 6E10) and antibody titers against Aβ (ELISA). AD behavioral phenotype was evaluated by performance in a battery of cognitive tests.Results: J20 mice displayed age-related Aβ plaque development and an AD-like behavioral phenotype. A consistent antibody response to the cyclic peptides was, however, not extended to Aβ, leaving plaque load unaffected. Nevertheless, immunization at young ages prevented working- and short-term spatial memory loss, but deteriorated long-term spatial learning and memory, at 12 months of age. Immunization at later ages did not affect any measured parameter.Conclusion: J20 mice provide a relevant model for AD to study potential anti-Aβ treatment. Early vaccination prevented short-term memory loss at later ages, but deteriorated long-term spatial memory, however without affecting Aβ pathology. Later vaccination had no effects, but optimal timing may require further investigation.

CNS inflammation is a major driver of MS pathology. Differential immune responses, including the adaptive and the innate immune system, are observed at various stages of MS and drive disease development and progression. Next to these immune-mediated mechanisms, other mediators contribute to MS pathology. These include immune-independent cell death of oligodendrocytes and neurons as well as oxidative stress-induced tissue damage. In particular, the complex influence of oxidative stress on inflammation and vice versa makes therapeutic interference complex. All approved MS therapeutics work by modulating the autoimmune response. However, despite substantial developments in the treatment of the relapsing-remitting form of MS, approved therapies for the progressive forms of MS as well as for MS-associated concomitants are limited and much needed. Here, we summarize the contribution of inflammation and oxidative stress to MS pathology and discuss consequences for MS therapy development.

Tumour necrosis factor (TNF) signalling is mediated via two receptors, TNF-receptor 1 (TNFR1) and TNF-receptor 2 (TNFR2), which work antithetically to balance CNS immune responses involved in autoimmune diseases such as multiple sclerosis. To determine the therapeutic potential of selectively inhibiting TNFR1 in mice with experimental autoimmune encephalomyelitis, we used chimeric human/mouse TNFR1 knock-in mice allowing the evaluation of antagonistic anti-human TNFR1 antibody efficacy. Treatment of mice after onset of disease with ATROSAB resulted in a robust amelioration of disease severity, correlating with reduced central nervous system immune cell infiltration. Long-term efficacy of treatment was achieved by treatment with the parental mouse anti-human TNFR1 antibody, H398, and extended by subsequent re-treatment of mice following relapse. Our data support the hypothesis that anti-TNFR1 therapy restricts immune cell infiltration across the blood-brain barrier through the down-regulation of TNF-induced adhesion molecules, rather than altering immune cell composition or activity. Collectively, we demonstrate the potential for anti-human TNFR1 therapies to effectively modulate immune responses in autoimmune disease.

INTRODUCTION: A possible target for stroke management is modulation of neuroinflammation. Evidence suggests that food components may exert anti-inflammatory properties and thus may reduce stroke-induced brain damage.AIM: To investigate the efficacy of a diet, containing anti-inflammatory ingredients, as treatment for focal ischemic brain damage induced by photothrombotic stroke in the somatosensory cortex of rats.RESULTS: Brain lesions were surrounded by strong astrogliosis on both day 7 and day 21 after stroke and were accompanied by a trend toward globally decreased glucose metabolism on day 7. The investigational diet applied 2 weeks before the ischemia did not affect astrocyte activation on day 7, but reduced it at day 21. The investigational diet applied immediately after the ischemia, increased astrocyte activation on day 7 and completely reversed this effect on day 21. Moreover, postischemic intervention increased glucose metabolism in somatosensory cortex ipsilateral to the lesion on day 7.CONCLUSION: This study reveals potentially beneficial effects of a diet containing elevated amounts of anti-inflammatory nutrients on the recovery from ischemic brain damage. Therefore, dietary intervention can be considered as an adjuvant therapy for recovery from this brain pathology.

Diamond has been a popular material for a variety of biological applications due to its favorable chemical, optical, mechanical and biocompatible properties. While the lattice orientation of crystalline material is known to alter the interaction between solids and biological materials, the effect of diamond's crystal orientation on biological applications is completely unknown. Here, we experimentally evaluate the influence of the crystal orientation by investigating the interaction between the , and surfaces of the single crystal diamond with biomolecules, cell culture medium, mammalian cells and bacteria. We show that the crystal orientation significantly alters these biological interactions. Most surprising is the two orders of magnitude difference in the number of bacteria adhering on surface compared to surface when both the surfaces were maintained under the same condition. We also observe differences in how small biomolecules attach to the surfaces. Neurons or HeLa cells on the other hand do not have clear preferences for either of the surfaces. To explain the observed differences, we theoretically estimated the surface charge for these three low index diamond surfaces and followed by the surface composition analysis using x-ray photoelectron spectroscopy (XPS). We conclude that the differences in negative surface charge, atomic composition and functional groups of the different surface orientations lead to significant variations in how the single crystal diamond surface interacts with the studied biological entities. This work isfinancially supported by Romana Schirhagl’s Eu-ropean Research Council grant (ERC STG - 714289) and a FOMprojectruimte (G-36). Additionally, Viraj Damle was supported by aMarie Curie Individual Postdoctoral Fellowship (DLV-838494) KaiqiWu by a CSC scholarship, and Aryan Morita by an LPDP grant. Thecomputational resources and services used in this work wereprovided by the VSC (Flemish Supercomputer Center), funded bythe Research Foundation-Flanders (FWO) and the Flemish Gov-ernment - department EWI.All of the imaging from this work was performed at the UMCGImaging and Microscopy Center (UMIC)

Major Depressive Disorder (MDD) is a heterogeneous disorder with a considerable symptomatic overlap with other psychiatric and somatic disorders. This study aims at providing evidence for association of a set of serum and urine biomarkers with MDD. We analyzed urine and serum samples of 40 MDD patients and 47 age- and sex-matched controls using 40 potential MDD biomarkers (21 serum biomarkers and 19 urine biomarkers). All participants were of Caucasian origin. We developed an algorithm to combine the heterogeneity at biomarker level. This method enabled the identification of correlating biomarkers based on differences in variation and distribution between groups, combined the outcome of the selected biomarkers, and calculated depression probability scores (the "bio depression score"). Phenotype permutation analysis showed a significant discrimination between MDD and euthymic (control) subjects for biomarkers in urine (P

Tumor necrosis factor receptor 2 (TNFR2) is a transmembrane receptor that promotes immune modulation and tissue regeneration and is recognized as a potential therapeutic target for multiple sclerosis (MS). However, TNFR2 also contributes to T effector cell function and macrophage-TNFR2 recently was shown to promote disease development in the experimental autoimmune encephalomyelitis (EAE) model of MS. We here demonstrate that systemic administration of a TNFR2 agonist alleviates peripheral and central inflammation, and reduces demyelination and neurodegeneration, indicating that protective signals induced by TNFR2 exceed potential pathogenic TNFR2-dependent responses. Our behavioral data show that systemic treatment of female EAE mice with a TNFR2 agonist is therapeutic on motor symptoms and promotes long-term recovery from neuropathic pain. Mechanistically, our data indicate that TNFR2 agonist treatment follows a dual mode of action and promotes both suppression of CNS autoimmunity and remyelination. Strategies based on the concept of exogenous activation of TNFR2 therefore hold great promise as a new therapeutic approach to treat motor and sensory disease in MS as well as other inflammatory diseases or neuropathic pain conditions.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive impairments. The classical symptoms of the disease include gradual deterioration of memory and language. Epidemiological studies indicate that around 25-40% of AD patients have sleep-wake cycle disturbances. Importantly, a series of studies suggested that the relationship between AD and sleep disturbance may be complex and bidirectional. Indeed, accumulation of the extracellular neuronal protein amyloid-beta (A beta) leads to altered sleep-wake behavior in both mice and humans. At the same time, disturbances of the normal sleep-wake cycle may facilitate AD pathogenesis. This paper will review the mechanisms underlying this potential interrelated connection including locus coeruleus damage, reductions in orexin neurotransmission, alterations in melatonin levels, and elevated cytokine levels. In addition, we will also highlight how both the development of AD and sleep disturbances lead to changes in intracellular signaling pathways involved in regulating neuronal plasticity and connectivity, particularly extremes in cofilin phosphorylation. Finally, current pharmacological and nonpharmacological therapeutic approaches will be discussed.

Despite the recognized role of tumor necrosis factor (TNF) in inflammation and neuronal degeneration, anti-TNF therapeutics failed to treat neurodegenerative diseases. Animal disease models had revealed the antithetic effects of the two TNF receptors (TNFR) in the central nervous system, whereby TNFR1 has been associated with inflammatory degeneration and TNFR2 with neuroprotection. We here show the therapeutic potential of selective inhibition of TNFR1 and activation of TNFR2 by ATROSAB, a TNFR1-selective antagonistic antibody, and EHD2-scTNFR2, an agonistic TNFR2-selective TNF, respectively, in a mouse model of NMDA-induced acute neurodegeneration. Coadministration of either ATROSAB or EHD2-scTNFR2 into the magnocellular nucleus basalis significantly protected cholinergic neurons and their cortical projections against cell death, and reverted the neurodegeneration-associated memory impairment in a passive avoidance paradigm. Simultaneous blocking of TNFR1 and TNFR2 signaling, however, abrogated the therapeutic effect. Our results uncover an essential role of TNFR2 in neuroprotection. Accordingly, the therapeutic activity of ATROSAB is mediated by shifting the balance of the antithetic activity of endogenous TNF toward TNFR2, which appears essential for neuroprotection. Our data also explain earlier results showing that complete blocking of TNF activity by anti-TNF drugs was detrimental rather than protective and argue for the use of next-generation TNFR-selective TNF therapeutics as an effective approach in treating neurodegenerative diseases.

Neuroinflammation is a common phenomenon in the pathology of many brain diseases. In this paper we explore whether selected vitamins and fatty acids known to modulate inflammation exert an effect on microglia, the key cell type involved in neuroinflammation. Previously these nutrients have been shown to exert anti-inflammatory properties acting on specific inflammatory pathways. We hypothesized that combining nutrients acting on converging anti-inflammatory pathways may lead to enhanced anti-inflammatory properties as compared to the action of a single nutrient. In this study, we investigated the anti-inflammatory effect of combinations of nutrients based on the ability to inhibit the LPS-induced release of nitric oxide and interleukin-6 from BV-2 cells. Results show that omega-3 fatty acids, vitamins A and D can individually reduce the LPS-induced secretion of the pro-inflammatory cytokines by By 2 cells. Moreover, we show that vitamins A, D and omega-3 fatty acids (docosahexaenoic and eicosapentaenoic) at concentrations where they individually had little effect, significantly reduced the secretion of the inflammatory mediator, nitric oxide, when they were combined. The conclusion of this study is that combining different nutrients acting on convergent anti-inflammatory pathways may result in an increased anti-inflammatory efficacy. (C) 2016 Elsevier Ltd. All rights reserved.

Background: Soluble oligomeric (misfolded) species of amyloid-beta (A beta) are the main mediators of toxicity in Alzheimer's disease (AD). These oligomers subsequently form aggregates of insoluble fibrils that precipitate as extracellular and perivascular plaques in the brain. Active immunization against A beta is a promising disease modifying strategy. However, eliciting an immune response against A beta in general may interfere with its biological function and was shown to cause unwanted side-effects. Therefore, we have developed a novel experimental vaccine based on conformational neo-epitopes that are exposed in the misfolded oligomeric A beta, inducing a specific antibody response.Objective: Here we investigate the protective effects of the experimental vaccine against oligomeric A beta(1-42)-induced neuronal fiber loss in vivo.Methods: C57BL/6 mice were immunized or mock-immunized. Antibody responses were measured by enzyme-linked immunosorbent assay. Next, mice received a stereotactic injection of oligomeric A beta(1-42) into the nucleus basalis of Meynert (NBM) on one side of the brain (lesion side), and scrambled A beta(1-42) peptide in the contralateral NBM (control side). The densities of choline acetyltransferase-stained cholinergic fibers origination from the NBM were measured in the parietal neocortex postmortem. The percentage of fiber loss in the lesion side was determined relative to the control side of the brain.Results: Immunized responders (79%) showed 23% less cholinergic fiber loss (p = 0.01) relative to mock-immunized mice. Moreover, fiber loss in immunized responders correlated negatively with the measured antibody responses (R-2 = 0.29, p = 0.02).Conclusion: These results may provide a lead towards a (prophylactic) vaccine to prevent or at least attenuate (early onset) AD symptoms.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Accumulating experimental evidence shows the important linkage between tumor necrosis factor-α (TNF) and AD, but the exact role of TNF in AD is still not completely understood. Although TNF-inhibitors are successfully used for treating several diseases, total inhibition of TNF can cause side effects, particularly in neurological diseases. This is attributed to the opposing roles of the two TNF receptors. TNF receptor 1 (TNFR1) predominantly mediates inflammatory and pro-apoptotic signaling pathways, whereas TNF receptor 2 (TNFR2) is neuroprotective and promotes tissue regeneration. Therefore, the specific activation of TNFR2 signaling, either by directly targeting TNFR2 via TNFR2 agonists or by blocking TNFR1 signaling with TNFR1-selective antagonists, seems a promising strategy for AD therapy. This mini-review discusses the involvement of TNFR2 and its signaling pathway in AD and outlines its potential application as therapeutic target. A better understanding of the function of TNFR2 may lead to the development of a treatment for AD.

Neuroinflammation has been implicated in the pathology of various psychiatric and neurodegenerative disorders. Accumulating evidence suggests that food components can modulate inflammatory processes, and therefore it could be hypothesized that such nutrients might exhibit therapeutic efficacy against these brain diseases. Rice bran is often discarded as a waste product, although it contains a wide range of potentially useful substances. Several rice fiber components from rice bran have been described as having antiinflammatory properties. This review summarizes the evidence supporting a modulatory effect of rice fiber components on symptoms in several animal models for neuroinflammation. In vitro studies on immune cells and in vivo studies on nutritional intervention in animal models of central and peripheral inflammation are discussed in the context of the potential use of rice fiber components for prevention and treatment of brain diseases in which neuroinflammation is involved.

BackgroundIn patients with heart failure (HF) depressive symptoms have been associated with mortality, as well as biological risk factors, including inflammation, nitric oxide (NO) regulation, and oxidative stress. We investigated the joint predictive value of depressive symptoms, inflammation and NO regulation on all-cause mortality in patients with HF, adjusted for covariates.MethodsSerum levels of inflammation (TNFα, sTNFr1, sTNFr2, IL-6, hsCRP, NGAL), NO regulation (l-arginine, ADMA, and SDMA), and oxidative stress (isoprostane 8-Epi Prostaglandin F2 Alpha) were measured in 104 patients with HF (mean age 65.7 ± SD 8.4 years, 28% women). Depressive symptoms (Beck Depression Inventory, BDI) were measured as continuous total, cognitive, and somatic symptoms, as well as categorized presence of mild/moderate depression (cut-off BDI ⩾10). In Cox proportional hazard models we adjusted for age, sex, poor exercise tolerance and comorbidity.ResultsAfter on average 6.1 years follow-up (SD = 2.9, range 0.4–9.2), 49 patients died. Total and somatic depressive symptoms, mild/moderate depression, higher NGAL, sTNFr2, IL-6, hsCRP and SDMA serum levels were significantly associated with a higher all-cause mortality rate, adjusted for covariates. The findings were most consistent for CRP level and somatic depressive symptoms. When combined, both depressive symptoms and markers of inflammation and NO regulation remained significantly associated with all-cause mortality. These associations were not confounded by age, sex, poor exercise tolerance and comorbidity.ConclusionDepressive symptoms and markers of inflammation and NO regulation are codominant risk factors for all-cause mortality in heart failure.KeywordsHeart failureDepressive symptomsInflammationCRPAll-cause mortalityNGALNO regulationMethylargininesPrognosis

Depression is more common in patients with cardiovascular disease than in the general population. Conversely, depression is a risk factor for developing cardiovascular disease. Comorbidity of these two pathologies worsens prognosis. Several mechanisms have been indicated in the link between cardiovascular disease and depression, including inflammation. Systemic inflammation can have long-lasting effects on the central nervous system, which could be associated with depression. NGAL is an inflammatory marker and elevated plasma levels are associated with both cardiovascular disease and depression. While patients with depression show elevated NGAL levels, in patients with comorbid heart failure, NGAL levels are significantly higher and associated with depression scores. Systemic inflammation evokes NGAL expression in the brain. This is considered a proinflammatory effect as it is involved in microglia activation and reactive astrocytosis. Animal studies support a direct link between NGAL and depression/anxiety associated behavior. In this review we focus on the role of NGAL in linking depression and cardiovascular disease.

Toxic levels of phenylalanine in blood and brain is a characteristic of (untreated) phenylketonuria (PKU), leading to cognitive deficits in PKU mice. In addition, our recent findings showed that PKU mice (as well as PKU patients) have a disturbed sleep/wake cycle. As a consequence, sleep loss may contribute to cognitive deficits in PKU. Sleep loss has been linked to increased activation of microglia in the hippocampus. In this study, we set out to examine morphological features of the microglia population in the hippocampus of the mouse PKU model, using both the C57Bl/6 and the BTBR strain and their wild-type controls (age 5.3 ± 0.5 months; n = 16 per group, both males and females; n = 8 each). Microglial activation is reflected by retraction and thickening of the dendritic branches and an increase in cell body size of a microglial cell. Such morphological changes of microglia were studied by way of immunohistochemical staining for Iba-1, a microglia-specific calcium binding protein. We measured the number of microglia in seven subregions of the dorsal hippocampus. The level of microglial activation was determined, based on the ratio between the soma size and total cell size (soma size plus the area covered by the dendritic branches). Results showed subtle but statistical significant activation of hippocampal microglia in the C57Bl6, but not in the BTBR, PKU mice when compared with their wild-type controls. Also the total number of microglia was higher in the C57Bl/6 PKU (compared to the wild-type) mouse, but not in the BTBR PKU mouse. It is concluded that the C57Bl/6 PKU mouse has mildly higher microglia activity, which may support rather than hamper hippocampal homeostasis. The results further indicate that high levels of phenylalanine or disturbed sleep patterns do not consequently cause hippocampal microglial activation in the PKU mouse. It is currently unknown why the two PKU mouse strains show these differences in number and activation level of their hippocampal microglia, and to what extent it influences hippocampal functioning. Further scrutinizing the role of microglia functioning in the context of PKU is therefore warranted.

Background: The majority of people with Down syndrome (DS) develop dementia due to Alzheimer's disease (AD). Neuropathological features are characterized by an accumulation of amyloid-beta (A beta) deposits and the presence of an activated immune response. Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a newly identified (neuro) inflammatory constituent in AD.Objective: This study examines NGAL as an inflammatory marker in DS and its associations with plasma A beta peptides according to the follow-up clinical diagnosis of dementia.Methods: Baseline serum NGAL and plasma A beta(40), A beta(42), A beta(n40), and A beta(n42) were quantified in 204 people with DS. The diagnosis of dementia in DS was established by follow-up clinical assessments. The following study groups were characterized: DS with AD at baseline (n = 67), DS without AD (n = 53), and non-demented DS individuals that converted to AD (n = 84). Serum NGAL was analyzed in 55 elderly non-DS, non-demented people.Results: Serum NGAL levels were significantly increased in DS subjects compared to non-DS people. Serum NGAL levels were not associated with clinical dementia symptoms in DS. However, NGAL was positively associated with A beta(42) and A beta(n42) in demented DS individuals and with A beta(40) and A beta(n40) in the non-demented DS group. NGAL was negatively associated with A beta(42)/A beta(40) and A beta(n42)/A beta(n40) ratios in converted DS subjects. These associations persisted for A beta(n40), A beta(42)/A beta(40), and A beta(n42)/A beta(n40) after adjusting for demographics measures, apolipoprotein E epsilon 4 allele, platelets, and anti-inflammatory medication.Conclusion: Serum NGAL levels are increased in DS and associated with distinct species of A beta depending on the progression of dementia as diagnosed by baseline and follow-up clinical assessments.

Objective: Nitric oxide (NO) regulation plays a critical role in cardiovascular diseases including heart failure (HF). Markers of NO dysregulation have been found in individuals with depression without cardiovascular disease. Because depression is associated with poor HF outcomes, the present study tested the hypothesis that depression is associated with a dysregulated NO pathway in patients with HF.Methods: Serum levels of NO regulation (L-arginine, asymmetric dimethylarginine [ADMA], and symmetric dimethylarginine [SDMA]) and oxidative stress (isoprostane 8-epi prostaglandin F2α) were measured in 104 patients with HF (mean [standard deviation] age = 65.7 [8.4] years, 28% women) at baseline and 12 months. Depressive symptoms were measured using the Beck Depression Inventory. The associations between depressive symptoms with markers of NO regulation were examined with mixed-model analysis, adjusted for age, sex, time of assessment, left ventricular ejection fraction, creatinine, and hypertension.Results: Depressive symptoms were correlated with a lower L-arginine/ADMA ratio (r = −0.22, p = .003) and higher SDMA levels (r = 0.28, p < .001). Associations were similar for somatic depressive symptoms and cognitive-affective symptoms (L-arginine/ADMA ratio: r = −0.20 [p = .009] versus r = −0.19 [p = .013]; ADMA: r = 0.16 [p = .043] versus r = 0.10 [p = .20]; SDMA: r = 0.27 [p < .001] versus r = 0.22 [p = .005], respectively). No associations were found between depressive symptoms and isoprostane. The association between depression and the L-arginine/ADMA ratio remained significant in multivariate adjusted models.Conclusions: Depressive symptoms were associated with markers of NO dysregulation, particularly the L-arginine/ADMA ratio and SDMA, in patients with HF. The lower L-arginine/ADMA ratio indicates less available NO, suggesting that NO-related endothelial dysfunction may play a role in the adverse risk of HF progression associated with depression.

Lipocalin 2 (Lcn2) has been implicated to play a role in various neurodegenerative diseases, and normalizing its overexpression may be of therapeutic potential. Iron chelators were found to reduce Lcn2 levels in certain animal models of CNS injury. Focusing on Alzheimer's disease (AD), we found that the iron chelators deferoxamine and deferiprone inhibited amyloid-β (Aβ)-induced Lcn2 production in cultured primary astrocytes. Accordingly, Aβ-exposure increased astrocytic ferritin production, indicating the possibility that Aβ induces iron accumulation in astrocytes. This effect was not significantly modulated by Lcn2. Known neuroprotective effects of iron chelators may rely in part on normalization of Lcn2 levels.

Depression adversely affects prognosis in heart failure (HF) patients. Inflammation is indicated as potential biological pathway in this co-morbidity. Since increased levels of the cytokine Neutrophil Gelatinase-Associated Lipocalin (NGAL) are predictive for HF prognosis, and recently indicated in patients with major depression, this study examined the association of serum NGAL levels with symptoms of depression in patients with HF. Serum NGAL levels were measured in 104 patients with HF (left ventricular ejection fraction, LVEF ⩽ 40). Depression, evaluated using the Beck Depression Inventory (BDI; total score, somatic and cognitive component), and the Hamilton Depression Rating scale (HAMD), at baseline and 12 months follow-up, was associated with NGAL levels using mixed model analysis. Analyses were adjusted for demographics measures, disease severity indicators, inflammation, comorbidity and medication. Increased serum NGAL levels were significantly associated with depression measured by HAMD (baseline: r = 0.25, p < .05) and BDI (baseline: r = 0.22, p < .05; 12 months: r = 0.37, p < .01). This association remained significant after adjustment for covariates; age, sex, time, LVEF, and creatinine (HAMD, t = 2.01, p = .047; BDI, t = 2.28, p = .024). NGAL was significantly associated with somatic- (p = 0.004), but not cognitive depressive symptoms (p = 0.32). NGAL levels were associated with the experienced HF-related functional limitations (6 min walk test), rather than the severity of cardiac dysfunction (LVEF). This study indicates that depression in patients with chronic HF is associated with elevated NGAL levels, independent of clinical severity of the underlying disease. Keywords: Lipocalin 2, Depression, Cognitive and somatic depressive symptoms, Inflammation, Heart failure, Follow-up

TNF-α plays important functional roles in the central nervous system during normal physiological circumstances via intricate signaling mechanisms between its receptors, TNF receptor 1 (TNFR1) and TNF receptor 2 (TNFR2). Although the roles of TNFR1 and TNFR2 in the diseased brain have received considerable attention, their functions on behavior and cognition in a non-inflammatory physiological aged environment are still unknown. In the present study we investigated the functional roles of TNFR1 and TNFR2 in learning and memory, motor performance and anxiety-like behavior via several behavioral and cognitive assessments in young and aged mice, deficient of either TNFR1 or TNFR2. Results from this study show that deletion of TNFR2 impairs novel object recognition, spatial memory recognition, contextual fear conditioning, motor performance and can increase anxiety-like behavior in young adult mice. Concerning the functions of TNFR1 and TNFR2 functioning in an aged environment, age caused memory impairment in spatial memory recognition independent of genotype. However, both young and aged mice deficient of TNFR2 performed poorly in the contextual fear conditioning test. These mice displayed decreased anxiety-like behavior, whereas mice deficient of TNFR1 were insusceptible to the effect of aging on anxiety-like behavior. This study provides novel knowledge on TNFR1 and TNFR2 functioning in behavior and cognition in young and aged mice in a non-inflammatory physiological environment.

Background: Although it is well established that late-life depression is associated with both systemic low-graded inflammation and cognitive impairment, the relation between inflammation and cognition in depressed older persons is still equivocal. The objective of this study is to examine the association between plasma Neutrophil Gelatinase-Associated Lipocalin (NGAL) concentrations and cognitive functioning in late-life depression, including the potentially moderating role of sex. Methods: A total of 369 depressed older persons (>= 60 years) from The Netherlands study of Depression in Older persons (NESDO) were included. Four cognitive domains, i.e. verbal memory, processing speed, interference control and attention were assessed with three cognitive tests (Stroop test, Wais Digit span test, and Rey's verbal learning test). Multiple linear regression analyses were applied with the four cognitive domains as dependent variables adjusted for confounders. Results: The association between NGAL levels and specific cognitive domains were sex-specific. In women, higher NGAL levels were associated with impaired verbal memory and lower processing speed. In men, higher NGAL levels were associated with worse interference control. Higher NGAL levels were not associated with attention. No sex-specific associations of either high sensitivity C-reactive protein (hsCRP) or interleukin-6 (IL-6) with cognitive functioning were found. Conclusion: This study shows sex-specific association of NGAL with cognitive functioning in late-life depression. (C) 2014 Elsevier Ltd. All rights reserved.

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon that affects an increasing number of patients. High comorbidity is observed between UC and other diseases in which inflammation may be involved, including brain diseases such as cognitive impairment, mental disorders, anxiety, and depression. To investigate the increased occurrence of these brain diseases in patients with UC, non-invasive methods for monitoring peripheral and central inflammation could be applied. Therefore, the goal of this study is to assess the feasibility of monitoring gut and brain inflammation in a rat model of chemically induced colitis by positron emission tomography (PET) with [C-11]PBR28, a tracer targeting the translocator protein (TSPO), which is upregulated when microglia and macrophages are activated.Colitis was induced in rats by intra-rectal injection of 2,4,6-trinitrobenzenesulfonic acid (TNBS). Rats with colitis and healthy control animals were subjected to [C-11]PBR28 PET of the abdomen followed by ex vivo biodistribution in order to assess whether inflammation in the gut could be detected. Another group of rats with colitis underwent repetitive [C-11]PBR28 PET imaging of the brain to investigate the development of neuroinflammation.Eleven days after TNBS injection, ex vivo biodistribution studies demonstrated increased [C-11]PBR28 uptake in the inflamed cecum and colon of rats with colitis as compared to healthy controls, whereas PET imaging did not show any difference between groups at any time. Similarly, repetitive PET imaging of the brain did not reveal any neuroinflammation induced by the TNBS administration in the colon. In contrast, significantly increased [C-11]PBR28 uptake in cerebellum could be detected in ex vivo biodistribution studies on day 11.Inflammation in both the gut and the brain of rats with chemically induced colitis was observed by ex vivo biodistribution. However, these effects could not be detected by [C-11]PBR28 PET imaging in our colitis model, which is likely due to spill-over effects and insufficient resolution of the PET camera.

Contains fulltext : 171035.pdf (Publisher’s version ) (Open Access) Co-existing depression worsens Alzheimer's disease (AD) pathology. Neutrophil gelatinase-associated lipocalin (NGAL) is a newly identified (neuro)inflammatory mediator in the pathophysiologies of both AD and depression. This study aimed to compare NGAL levels in healthy controls, AD without depression (AD-D), and AD with co-existing depression (AD+D) patients. Protein levels of NGAL and its receptors, 24p3R and megalin, were assessed in nine brain regions from healthy controls (n = 19), AD-D (n = 19), and AD+D (n = 21) patients. NGAL levels in AD-D patients were significantly increased in brain regions commonly associated with AD. In the hippocampus, NGAL levels were even further increased in AD+D subjects. Unexpectedly, NGAL levels in the prefrontal cortex of AD+D patients were comparable to those in controls. Megalin levels were increased in BA11 and amygdala of AD+D patients, while no changes in 24p3R were detected. These findings indicate significant differences in neuroimmunological regulation between AD patients with and without co-existing depression. Considering its known effects, elevated NGAL levels might actively promote neuropathological processes in AD with and without depression.

Electroconvulsive therapy (ECT) is an effective treatment for depression, but can have negative side effects including amnesia. The mechanisms of action underlying both the antidepressant and side effects of ECT are not well understood. An equivalent manipulation that is conducted in experimental animals is electroconvulsive seizure (ECS). Rodent studies have provided valuable insights into potential mechanisms underlying the antidepressant and side effects of ECT. However, relatively few studies have investigated the effects of ECS in animal models with a depression-relevant manipulation such as chronic stress. In the present study, mice were first exposed to chronic social stress (CSS) or a control procedure for 15 days followed by ECS or a sham procedure for 10 days. Behavioral effects were investigated using an auditory fear conditioning (learning) and expression (memory) test and a treadmill-running fatigue test. Thereafter, immunohistochemistry was conducted on brain material using the microglial marker Iba-1 and the cholinergic fibre marker ChAT. CSS did not increase fear learning and memory in the present experimental design; in both the control and CSS mice ECS reduced fear learning and fear memory expression. CSS induced the expected fatigue-like effect in the treadmill-running test; ECS induced increased fatigue in CSS and control mice. In CSS and control mice ECS induced inflammation in hippocampus in terms of increased expression of Iba-1 in radiatum of CA1 and CA3. CSS and ECS both reduced acetylcholine function in hippocampus as indicated by decreased expression of ChAT in several hippocampal sub-regions. Therefore, CSS increased fatigue and reduced hippocampal ChAT activity and, rather than reversing these effects, a repeated ECS regimen resulted in impaired fear learning-memory, increased fatigue, increased hippocampal Iba-1 expression, and decreased hippocampal ChAT expression. As such, the current model does not provide insights into the mechanism of ECT antidepressant function but does provide evidence for pathophysiological mechanisms that might contribute to important ECT side-effects.

Objective: Systemic low graded inflammation has been identified as a possible biological pathway in late-life depression. Identification of inflammatory markers and their association with characteristics of depression is essential with the aim to improve diagnosis and therapeutic approaches. This study examines the determinants of plasma Neutrophil Gelatinase-Associated Lipocalin (NGAL), which is selectively triggered by TNF alpha. receptor 1 signaling within the central nervous system, and its association with late-life depressive disorder.Methods: Baseline data were obtained from a well-characterized prospective cohort study of 350 depressed and 129 non-depressed older persons (>= 60 years). Past 6 month diagnosis of major depressive disorder (MDD) according to DSM-IV-TR criteria was assessed with the Composite International Diagnostic Interview (CIDI 2.0). Potential determinants of plasma NGAL included sociodemographic characteristics, lifestyle and psychiatric and physical comorbidity.Results: Plasma NGAL concentrations were significantly associated with age, male gender, smoking and waist circumference. Adjusted for these determinants, depressed patients had significantly higher NGAL plasma levels compared to non-depressed comparison group. Depressed patients who did not meet full criteria for MDD in the month before sampling (partially remitted) had lower plasma NGAL levels compared with those who did. Subjects with a recurrent depression had higher plasma NGAL levels compared to those with a first episode. NGAL levels were neither related with specific symptom profiles of depression nor with antidepressant drug use.Conclusion: Adjusted for confounders, NGAL plasma levels are increased in depressed older persons, without any effect of antidepressant medication and age of onset. (C) 2013 Elsevier Inc. All rights reserved.

Alzheimer's disease (AD) is associated with an altered immune response, resulting in chronic increased inflammatory cytokine production with a prominent role of TNF-alpha. TNF-alpha signals are mediated by two receptors: TNF receptor 1 (TNFR1) and TNF receptor 2 (TNFR2). Signaling through TNFR2 is associated with neuroprotection, whereas signaling through TNFR1 is generally proinflammatory and proapoptotic. Here, we have identified a TNF-alpha-induced proinflammatory agent, lipocalin 2 (Lcn2) via gene array in murine primary cortical neurons. Further investigation showed that Lcn2 protein production and secretion were activated solely upon TNFR1 stimulation when primary murine neurons, astrocytes, and microglia were treated with TNFR1 and TNFR2 agonistic antibodies. Lcn2 was found to be significantly decreased in CSF of human patients with mild cognitive impairment and AD and increased in brain regions associated with AD pathology in human postmortem brain tissue. Mechanistic studies in cultures of primary cortical neurons showed that Lcn2 sensitizes nerve cells to beta-amyloid toxicity. Moreover, Lcn2 silences a TNFR2-mediated protective neuronal signaling cascade in neurons, pivotal for TNF-alpha-mediated neuroprotection. The present study introduces Lcn2 as a molecular actor in neuroinflammation in early clinical stages of AD.-Naud, P.J.W., Nyakas, C., Eiden, L. E., Ait-Ali, D., van der Heide, R., Engelborghs, S., Luiten, P. G. M., De Deyn, P. P., den Boer, J.A., Eisel, U. L. M. Lipocalin 2: Novel component of proinflammatory signaling in Alzheimer's disease. FASEB J. 26, 2811-2823 (2012). www.fasebj.org

Indoleamine 2,3-dioxygenase (IDO), an enzyme which is activated by pro-inflammatory cytokines, has been suggested as a potential link between neuroinflammatory processes in neurodegenerative diseases (like Alzheimer's disease) and depression. The present study aimed to determine whether neuroinflammation-induced increased IDO levels in the mammalian brain will lead to depressive-like behavior. Neuroinflammation was initiated in mice by a single intracerebroventricular injection of lipopolysaccharide (LPS). Cerebral inflammation was monitored 1, 2, 3 and 4 days after the injection with small-animal positron emission tomography (PET) using the inflammatory marker [C-11]-PK11195. In the presence or absence of systemically applied 1-methyl-tryptophan (1-MT), a competitive IDO-inhibitor, we assessed the development of depressive-like behavioral symptoms in parallel with IDO expression and activity. The PK11195 PET signal reached a highly significant peak 3 days after LPS injection, while these animals displayed a significant increase of depressive-like behavior in the forced swim test compared to vehicle-injected animals. These findings were paralleled by a significant increase of IDO in the brainstem, and an increased kynurenine/tryptophan ratio in the serum. Moreover, we report here for the first time, that inhibition of IDO by 1-MT in centrally induced neuroinflammation under experimental conditions can prevent the development of depressive-like behavior.

Extensive research has been performed to unravel the mechanistic signaling pathways mediated by tumor necrosis factor receptor 1 (TNFR1), by contrast there is limited knowledge on cellular signaling upon activation of TNFR2. Recently published data have revealed that these two receptors not only function independently, but also can influence each other via cross-talk between the different signaling pathways initiated by TNFR1 and TNFR2 stimulation. Furthermore, the complexity of this cross-talk is also dependent on the different signaling kinetics between TNFR1 and TNFR2, by which a delicate balance between cell survival and apoptosis can be maintained. Some known signaling factors and the kinetics that are involved in the receptor cross-talk between TNFR1 and TNFR2 are the topic of this review.

Knowledge on the molecular mechanisms involved in memory retrieval is limited due to the lack of tools to study this stage of the memory process. Here we report that exchange proteins activated by cAMP (Epac) play a surprisingly specific role in memory retrieval. Intrahippocampal injection of the Epac activator 8-pCPT-2'O-Me-cAMP was shown to improve fear memory retrieval in contextual fear conditioning whereas acquisition and consolidation were not affected. The retrieval enhancing effect of the Epac activator was even more prominent in the passive avoidance paradigm. Down-regulation of Epac2 expression in the hippocampal CA1 area impaired fear memory retrieval when the memory test was performed 72 h after training, but not when tested after 17 days. Our data thus identify an important time-limited role for hippocampal Epac2 signaling in cognition and opens new avenues to investigate the molecular mechanisms underlying memory retrieval. (C) 2009 Wiley-Liss, Inc.

Goldberg–Shprintzen syndrome (GOSHS) is a rare clinical disorder characterized by central and enteric nervous system defects. This syndrome is caused by inactivating mutations in the Kinesin Binding Protein (KBP) gene, which encodes a protein of which the precise function is largely unclear. We show that KBP expression is up-regulated during neuronal development in mouse cortical neurons. Moreover, KBP-depleted PC12 cells were defective in nerve growth factor-induced differentiation and neurite outgrowth, suggesting that KBP is required for cell differentiation and neurite development. To identify KBP interacting proteins, we performed a yeast two-hybrid screen and found that KBP binds almost exclusively to microtubule associated or related proteins, specifically SCG10 and several kinesins. We confirmed these results by validating KBP interaction with one of these proteins: SCG10, a microtubule destabilizing protein. Zebrafish studies further demonstrated an epistatic interaction between KBP and SCG10 in vivo . To investigate the possibility of direct interaction between KBP and microtubules, we undertook co-localization and in vitro binding assays, but found no evidence of direct binding. Thus, our data indicate that KBP is involved in neuronal differentiation and that the central and enteric nervous system defects seen in GOSHS are likely caused by microtubule-related defects.

Besides a beneficial cardiovascular effect, it was recently suggested that statins can also exert neuroprotective actions. In a previous study, we provided in vitro evidence that lovastatin treatment abates excitotoxic cell death in primary cortical neurons. Here, we investigated the neuroprotective effect of lovastatin in an in vivo mouse model. We found that administration of lovastatin (20 mg/kg) significantly protects cholinergic neurons and their cortical projections against N-methyl-D-aspartate (60 nmol)-induced cell death in the magnocellular nucleus basalis, a neuronal cell group that is characteristically affected in Alzheimer's disease. Furthermore, lovastatin-mediated neuroprotection was shown to be dependent on protein kinase B (PKB)/Akt signaling since treatment with the PKB/Akt inhibitor LY294002 blocked the lovastatin-induced neuroprotective effect. The loss of cholinergic neurons after the lesion in the magnocellular nucleus basalis resulted in memory impairment as tested in a passive avoidance paradigm. This was reverted by pre-lesion lovastatin treatment. From these studies we conclude that treatment with lovastatin may provide protection against neuronal injury in excitotoxic conditions associated with neurodegenerative diseases including Alzheimer's disease.