Search

Cerebrovascular disease underpins vascular dementia (VaD), but structural and functional changes to the cerebral vasculature contribute to disease pathology and cognitive decline in Alzheimer's disease (AD). In this review, we discuss the contribution of cerebral amyloid angiopathy and non-amyloid small vessel disease in AD, and the accompanying changes to the density, maintenance and remodelling of vessels (including alterations to the composition and function of the cerebrovascular basement membrane). We consider how abnormalities of the constituent cells of the neurovascular unit - particularly of endothelial cells and pericytes - and impairment of the blood-brain barrier (BBB) impact on the pathogenesis of AD. We also discuss how changes to the cerebral vasculature are likely to impair Aβ clearance - both intra-periarteriolar drainage (IPAD) and transport of Aβ peptides across the BBB, and how impaired neurovascular coupling and reduced blood flow in relation to metabolic demand increase amyloidogenic processing of APP and the production of Aβ. We review the vasoactive properties of Aβ peptides themselves, and the probable bi-directional relationship between vascular dysfunction and Aβ accumulation in AD. Lastly, we discuss recent methodological advances in transcriptomics and imaging that have provided novel insights into vascular changes in AD, and recent advances in assessment of the retina that allow in vivo detection of vascular changes in the early stages of AD.

Objectives\ud Vaccines that prime Wilms' tumor 1 (WT1)‐specific CD8+ T cells are attractive cancer immunotherapies. However, immunogenicity and clinical response rates may be enhanced by delivering WT1 to CD141+ dendritic cells (DCs). The C‐type lectin‐like receptor CLEC9A is expressed exclusively by CD141+ DCs and regulates CD8+ T‐cell responses. We developed a new vaccine comprising a human anti‐CLEC9A antibody fused to WT1 and investigated its capacity to target human CD141+ DCs and activate naïve and memory WT1‐specific CD8+ T cells.\ud \ud Methods\ud WT1 was genetically fused to antibodies specific for human CLEC9A, DEC‐205 or β‐galactosidase (untargeted control). Activation of WT1‐specific CD8+ T‐cell lines following cross‐presentation by CD141+ DCs was quantified by IFNγ ELISPOT. Humanised mice reconstituted with human immune cell subsets, including a repertoire of naïve WT1‐specific CD8+ T cells, were used to investigate naïve WT1‐specific CD8+ T‐cell priming.\ud \ud Results\ud The CLEC9A‐WT1 vaccine promoted cross‐presentation of WT1 epitopes to CD8+ T cells and mediated priming of naïve CD8+ T cells more effectively than the DEC‐205‐WT1 and untargeted control‐WT1 vaccines.\ud \ud Conclusions\ud Delivery of WT1 to CD141+ DCs via CLEC9A stimulates CD8+ T cells more potently than either untargeted delivery or widespread delivery to all Ag‐presenting cells via DEC‐205, suggesting that cross‐presentation by CD141+ DCs is sufficient for effective CD8+ T‐cell priming in humans. The CLEC9A‐WT1 vaccine is a promising candidate immunotherapy for malignancies that express WT1.

There is a perfusion deficit in Alzheimer's disease (AD), commencing in the precuneus and spreading to other parts of the cerebral cortex. The deficit anticipates the development of dementia, contributes to brain damage, and is caused by both functional and structural abnormalities of the cerebral vasculature. Most of the abnormalities are probably secondary to the accumulation of Aβ but the consequent hypoperfusion may, in turn, increase Aβ production. In the early stages of disease, abnormalities that cause vasoconstriction predominate. These include cholinergic vascular denervation, inhibition of endothelial nitric oxide synthase, increased production of endothelin-1 production and possibly also of angiotensin II. Patients with AD also have an increased prevalence of structural disease of cerebral microvessels, particularly CAA and capillary damage, and particularly in the later stages of disease these are likely to make an important contribution to the cerebral hypoperfusion. The metabolic abnormalities that cause early vascular dysfunction offer several targets for therapeutic intervention. However, for intervention to be effective it probably needs to be early. Prolonged cerebral hypoperfusion may induce compensatory circulatory changes that are themselves damaging, including hypertension and small vessel disease. This has implications for the use of antihypertensive drugs once there is accumulation of Aβ within the brain.

Clusterin, also known as apoJ, is a lipoprotein abundantly expressed within the CNS. It regulates Aβ fibril formation and toxicity and facilitates amyloid-β (Aβ) transport across the blood-brain barrier. Genome-wide association studies have shown variations in the clusterin gene (CLU) to influence the risk of developing sporadic Alzheimer's disease (AD). To explore whether clusterin modulates the regional deposition of Aβ, we measured levels of soluble (NP40-extracted) and insoluble (guanidine-HCl-extracted) clusterin, Aβ40 and Aβ42 by sandwich ELISA in brain regions with a predilection for amyloid pathology-mid-frontal cortex (MF), cingulate cortex (CC), parahippocampal cortex (PH), and regions with little or no pathology-thalamus (TH) and white matter (WM). Clusterin level was highest in regions with plaque pathology (MF, CC, PH and PC), approximately mirroring the regional distribution of Aβ. It was significantly higher in AD than controls, and correlated positively with Aβ42 and insoluble Aβ40. Soluble clusterin level rose significantly with severity of cerebral amyloid angiopathy, and in MF and PC regions was highest in APOE ɛ4 homozygotes. In the TH and WM (areas with little amyloid pathology) clusterin was unaltered in AD and did not correlate with Aβ level. There was a significant positive correlation between the concentration of clusterin and the regional levels of insoluble Aβ42; however, the molar ratio of clusterin : Aβ42 declined with insoluble Aβ42 level in a region-dependent manner, being lowest in regions with predilection for Aβ plaque pathology. Under physiological conditions, clusterin reduces aggregation and promotes clearance of Aβ. Our findings indicate that in AD, clusterin increases, particularly in regions with most abundant Aβ, but because the increase does not match the rising level of Aβ42, the molar ratio of clusterin : Aβ42 in those regions falls, probably contributing to Aβ deposition within the tissue.

Haemophilia remains a complex disorder to diagnose and manage, requiring close cooperation between multidisciplinary healthcare professionals. There are still many unmet challenges in haemophilia care. The first Team Haemophilia Education (THE) meeting, held on 7-8 May 2015 in Amsterdam, The Netherlands, aimed to promote the optimal care of haemophilia patients through education of the multidisciplinary treatment team. This was achieved by reviewing the latest developments in haemophilia management, considering how these can be implemented in the clinic to improve patient care and providing a platform for networking and debate for all haemophilia treatment team members. Haemophilia treatment centres from several countries were asked to complete a premeeting online questionnaire to establish the biggest challenges that they face when managing patients. The concerns expressed were used to develop the agenda, which comprised a combination of formal presentations, case studies and informal workshops covering such topics as pharmacokinetics, laboratory assays and tailoring of treatment to individual patients. This report is a summary of the key developments in haemophilia care presented by various investigators and healthcare professionals at THE meeting 2015.

Aim To determine the scaling factors required for inclusion of renal drug glucuronidation clearance in the prediction of total clearance via glucuronidation (CLUGT ). Methods Microsomal protein per gram of kidney (MPPGK) was determined for human 'mixed' kidney (n = 5) microsomes (MKM). The glucuronidation activities of deferiprone (DEF), propofol (PRO) and zidovudine (AZT) by MKM and paired cortical (KCM) and medullary (KMM) microsomes were measured, along with the UGT 1A6, 1A9 and 2B7 protein contents of each enzyme source. Unbound intrinsic clearances (CLint,u,UGT ) for PRO and morphine (MOR; 3- and 6-) glucuronidation by MKM, human liver microsomes (HLM) and recombinant UGT1A9 and 2B7 were additionally determined. Data were scaled using in vitro-in vivo extrapolation (IV-IVE) approaches to assess the influence of renal CLint,u,UGT on the prediction accuracy of the calculated CLUGT values of PRO and MOR. Results MPPGK was 9.3 ± 2.0 mg g(-1) (mean ± SD). The respective rates of DEF (UGT1A6), PRO (UGT1A9) and AZT (UGT2B7) glucuronidation by KCM were 1.4-, 5.2- and 10.5-fold higher than those for KMM. UGT 1A6, 1A9 and 2B7 were the only enzymes expressed in kidney. Consistent with the activity data, the abundance of each of these enzymes was greater in KCM than in KMM. The abundance of UGT1A9 in MKM (61.3 pmol mg(-1) ) was 2.7 fold higher than that reported for HLM. Conclusions Scaled renal PRO glucuronidation CLint,u,UGT was double that of liver. Renal CLint,u,UGT should be accounted for in the IV-IVE of UGT1A9 and considered for UGT1A6 and 2B7 substrates.

Aims Deposition of amyloid beta (Aβ) in the brain is one of the defining abnormalities of Alzheimer's disease (AD). Phosphorylation of Aβ at serine 8 (pAβ) has been implicated in its aggregation in vitro and pAβ level has been shown to be significantly elevated in AD. We aimed to assess the specificity of pAβ for AD and have investigated associations of pAβ with parenchymal and cerebrovascular accumulation of Aβ, disease progression, angiotensin-converting enzyme activity and APOE genotype. Methods The distribution of pAβ was studied by immunohistochemistry in sporadic and familial AD, pure dementia with Lewy bodies (DLB), pure vascular dementia (VaD) and age-matched controls. Soluble and insoluble (guanidine-extractable) pAβ level was measured by enzyme-linked immunosorbent assay (ELISA) in the midfrontal and parahippocampal cortex in sporadic AD (n = 20, 10 with Braak tangle stages of III–IV and 10 of stages V–VI), DLB (n = 10), VaD (n = 10) and age-matched controls (n = 20). Results We found pAβ to be associated with only a subset of Aβ plaques and vascular deposits in sporadic and familial AD, with absent or minimal immunohistochemically detectable pAβ in control, DLB and VaD brains. In both brain regions, insoluble pAβ level was significantly elevated only in advanced AD (Braak tangle stage of V or VI) and in the parahippocampus soluble and insoluble pAβ level increased with the number of APOE e4 alleles. Conclusions These results indicate that pAβ accumulation in the parenchyma and vasculature is largely restricted to late-stage AD (Braak tangle stage V–VI).

Neuroimaging has revealed a range of white matter abnormalities that are common in dementia, some that predict cognitive decline. The abnormalities may result from structural diseases of the cerebral vasculature, such as arteriolosclerosis and amyloid angiopathy, but can also be caused by nonstructural vascular abnormalities (eg, of vascular contractility or permeability), neurovascular instability or extracranial cardiac or vascular disease. Conventional histopathological assessment of the white matter has tended to conflate morphological vascular abnormalities with changes that reflect altered interstitial fluid dynamics or white matter ischemic damage, even though the latter may be of extracranial or nonstructural etiology. However, histopathology is being supplemented by biochemical approaches, including the measurement of proteins involved in the molecular responses to brain ischemia, myelin proteins differentially susceptible to ischemic damage, vessel-associated proteins that allow rapid measurement of microvessel density, markers of blood-brain barrier dysfunction and axonal injury, and mediators of white matter damage. By combining neuroimaging with histopathology and biochemical analysis, we can provide reproducible, quantitative data on the severity of white matter damage, and information on its etiology and pathogenesis. Together these have the potential to inform and improve treatment, particularly in forms of dementia to which white matter hypoperfusion makes a significant contribution.

Most rebels have a cause, and the expression of internal criticism and dissent is vital for healthy civic and collective functioning. Here, we review the normative conflict model (NCM), which posits that social identities are key to understanding conformity and deviance in group contexts. The NCM hypothesizes that strongly identified group members are willing to articulate critical and dissenting opinions when they believe that doing so is in the interest of the collective. In this paper, we conceptually advance the NCM by exploring how responses to group norms can be understood from a goal system perspective, conceptualizing dissent decisions as often involving choices between conflicting goals. We review the evidence for this approach to dissent and outline a range of future directions.

In dementia with Lewy bodies (DLB), blood flow tends to be reduced in the occipital cortex. We previously showed elevated activity of the endothelin and angiotensin pathways in Alzheimer's disease (AD). We have measured endothelin-1 (ET-1) level and angiotensin-converting enzyme (ACE) activity in the occipital cortex in DLB and control brains. We also measured vascular endothelial growth factor (VEGF); factor VIII-related antigen (FVIIIRA) to indicate microvessel density; myelin-associated glycoprotein (MAG), a marker of ante-mortem hypoperfusion; total α-synuclein (α-syn) and α-synuclein phosphorylated at Ser129 (α-syn-p129). In contrast to findings in AD, ACE activity and ET-1 level were unchanged in DLB compared with controls. VEGF and FVIIIRA levels were, however, significantly lower in DLB. VEGF correlated positively with MAG concentration (in keeping with a relationship between reduction in VEGF and hypoperfusion), and negatively with α-syn and α-syn-p129 levels. Both α-syn and α-syn-p129 levels increased in human SH-SY5Y neuroblastoma cells after oxygen-glucose deprivation (OGD), and VEGF level was reduced in SH-SY5Y cells overexpressing α-syn. Taken together, our findings suggest that reduced microvessel density rather than vasoconstriction is responsible for lower occipital blood flow in DLB, and that the loss of microvessels may result from VEGF deficiency, possible secondary to the accumulation of α-syn.

In this critical review, we survey the wide range of chemical reactions that have been confined within carbon nanotubes, particularly emphasising how the pairwise interactions between the catalysts, reactants, transition states and products of a particular molecular transformation with the host nanotube can be used to control the yields and distributions of products of chemical reactions. We demonstrate that nanoscale confinement within carbon nanotubes enables the control of catalyst activity, morphology and stability, influences the local concentration of reactants and products thus affecting equilibria, rates and selectivity, pre-arranges the reactants for desired reactions and alters the relative stability of isomeric products. We critically evaluate the relative advantages and disadvantages of the confinement of chemical reactions inside carbon nanotubes from a chemical perspective and describe how further developments in the controlled synthesis of carbon nanotubes and the incorporation of multifunctionality are essential for the development of this ever-expanding field, ultimately leading to the effective control of the pathways of chemical reactions through the rational design of multi-functional carbon nanoreactors.

Knowledge of the metabolic stability of newly discovered drug candidates eliminated by metabolism is essential for predicting the pharmacokinetic (PK) parameters that underpin dosing and dosage frequency. Further, characterization of the enzyme(s) responsible for metabolism (reaction phenotyping) allows prediction, at least at the qualitative level, of factors (including metabolic drug-drug interactions) likely to alter the clearance of both new chemical entities (NCEs) and established drugs. Microsomes are typically used as the enzyme source for the measurement of metabolic stability and for reaction phenotyping because they express the major drug-metabolizing enzymes cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT), along with others that contribute to drug metabolism. Described in this unit are methods for microsome isolation, as well as for the determination of metabolic stability and metabolite formation (including kinetics). © 2016 by John Wiley & Sons, Inc.

Long-term, continuous prophylaxis for haemophilia began at a modest scale during the 1950s and 1960s in Sweden and The Netherlands. In the face of high cost and impediments to the performance of longitudinal, well-designed studies, it was decades before prophylaxis was considered to be the best practice in countries that could afford the cost. In 2007 and 2011, the only prospective randomized studies ever performed confirmed what large cohort studies in Europe had long since shown. Today, focus is on when to start prophylaxis, dosing and when/if to stop. Retrospective comparisons of the Swedish and Dutch cohorts, where different strategies have been used, indicate that a costly, high-dose regimen improves outcome, but not dramatically. A prospective comparison is now underway. Treatment, clinical outcome, clotting factor consumption and socioeconomic parameters will be compared between the two strategies. Results are expected to provide greater insight into the long-term consequences of the different prophylactic treatment strategies. The economic justification for prophylaxis has been addressed in several studies with varying results. While the majority (implicitly) suggest that prophylaxis is not cost effective at conventional willingness to pay for additional units in health thresholds, their results vary markedly. Closer inspection suggests that the primary reasons results differ include different definitions of prophylaxis, clotting factor price, discount rates, choice of outcome measures and time horizon.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Many drugs inhibit or induce cytochrome P450 enzymes (CYP) to cause clinically significant changes in the concentrations of other drugs, i.e. ‘perpetrate’ pharmacokinetic drug–drug interactions (PK-DDIs). • Tables that list the substrates, inhibitors and inducers of CYP are common, but they lack consistency and are constructed from evidence of variable quality. WHAT THIS STUDY ADDS • This is the first study to catalogue important perpetrators of PK-DDIs using objective criteria and clinical pharmacokinetic drug interaction studies. This information is intended to inform clinical decisions on PK-DDIs. • Existing tables of CYP inhibitors and inducers have low sensitivity and low positive predictive value in identifying the major perpetrators of PK-DDIs. • Several drugs were identified which potentially perpetrate CYP-mediated PK-DDIs, but quality clinical pharmacokinetic interaction studies are lacking. This information may be used to inform future research. AIMS To catalogue the perpetrators of CYP-mediated pharmacokinetic drug–drug interactions (PK-DDIs) using clinically relevant criteria, and to compare this with an analogous catalogue. METHODS Candidate inhibitors and inducers of CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A (‘perpetrators’) were evaluated using published clinical pharmacokinetic interaction studies. Studies were selected on the basis of ≥six human subjects, use of a validated in vivo probe substrate for the CYP enzyme, and clinically relevant dosing. Inhibitors were described according to the FDA classifications of strong, moderate or weak, whereas inducers were classified as major (≥twofold decrease in AUC) or weak (

Despite accumulating evidence of a central role for oligomeric amyloid beta (Abeta) in the pathogenesis of Alzheimer's Disease (AD), there is scant information on the relationship between the levels and distribution of oligomeric Abeta and those of other neurodegenerative abnormalities in AD. In the present study, we have found oligomeric Abeta to be associated with both diffuse and neuritic plaques (mostly co-localized with Abeta(1-42)) and with cerebrovascular deposits of Abeta in paraffin sections of formalin-fixed human brain tissue. The amount of oligomeric Abeta that was labeled in the sections correlated with total Abeta plaque load, but not phospho-tau load, cerebral amyloid angiopathy (CAA) severity or APOE genotype. Although soluble, oligomeric and insoluble Abeta levels were all significantly increased in AD brain homogenates, case-to-case variation and overlap between AD and controls were considerable. Over the age-range studied (43-98 years), the levels of soluble Abeta, oligomeric Abeta(42), oligomeric Abeta(40) and insoluble Abeta did not vary significantly with age. Oligomeric Abeta(1-42) and insoluble Abeta levels were significantly higher in women. Overall, the level of insoluble Abeta, but neither oligomeric nor soluble Abeta, was associated with Braak stage, CAA severity and APOEepsilon4 frequency, raising questions as to the role of soluble and oligomeric Abeta in the progression of AD.

We recently found that insoluble Abeta increases, but soluble Abeta decreases with age in normal brains. We now report the changes in activities of beta-secretase (BACE-1) and Abeta-degrading enzymes with age, and their relationships to concentrations of soluble and insoluble Abeta. We measured BACE-1 activity and the levels and activities of neprilysin (NEP), insulin-degrading enzyme (IDE) and angiotensin-converting enzyme (ACE) in normal control brains (16 years-95 years). We also compared the measurements to those in AD. BACE-1 activity correlated closely with age in controls and was significantly higher in AD. In controls, NEP and IDE activities (but not protein levels) increased with age but ACE activity and level did not. BACE-1 activity correlated directly with insoluble but inversely with soluble Abeta. IDE activity correlated directly with insoluble Abeta and NEP activity was inversely related to soluble Abeta. ACE level correlated directly with insoluble and inversely with soluble Abeta in controls but not AD. Both Abeta-synthesizing and -degrading enzyme activities increase with age, coinciding with declining soluble Abeta and increasing insoluble Abeta. Further research is needed to establish whether these changes in enzyme activity and Abeta levels are causally related and if so how.

Little is known about the relationship between soluble amyloid beta (Abeta) and age. We have measured soluble and insoluble Abeta by enzyme-linked immunosorbent assay (ELISA) in post-mortem frontal cortex in normal brains (16-95 years) and AD. Insoluble Abeta increased with age, and was significantly higher in Alzheimer's disease (AD) than age-matched controls. However, levels of soluble Abeta declined with age and were significantly greater in younger adults than older adults with or without AD. In AD, insoluble : soluble Abeta ratio was much higher than in age-matched controls. The high levels of soluble Abeta in young adults included oligomeric species of Abeta(1-42). These observations do not preclude Abeta oligomers as neurotoxic mediators of AD but suggest that if they are, the toxicity may be restricted to certain species (eg, beta-pleated protofibrillar species not detected by our assay) or takes decades to manifest. The dramatically increased insoluble : soluble Abeta in AD points to an altered dynamic equilibrium of Abeta in AD, reflecting both enhanced aggregation and continued overproduction or impaired removal of the soluble peptide in older age, when the concentration of this peptide should be declining.

By using Fink's taxonomy to shape new learning goals and creating new learning and assessment activities, two teachers succeeded in raising students' awareness of the value of their courses and enabled them to become more reflective learners in the process.

In Alzheimer's disease (AD) Abeta accumulates because of imbalance between the production of Abeta and its removal from the brain. There is increasing evidence that in most sporadic forms of AD, the accumulation of Abeta is partly, if not in some cases solely, because of defects in its removal--mediated through a combination of diffusion along perivascular extracellular matrix, transport across vessel walls into the blood stream and enzymatic degradation. Multiple enzymes within the central nervous system (CNS) are capable of degrading Abeta. Most are produced by neurons or glia, but some are expressed in the cerebral vasculature, where reduced Abeta-degrading activity may contribute to the development of cerebral amyloid angiopathy (CAA). Neprilysin and insulin-degrading enzyme (IDE), which have been most extensively studied, are expressed both neuronally and within the vasculature. The levels of both of these enzymes are reduced in AD although the correlation with enzyme activity is still not entirely clear. Other enzymes shown capable of degrading Abetain vitro or in animal studies include plasmin; endothelin-converting enzymes ECE-1 and -2; matrix metalloproteinases MMP-2, -3 and -9; and angiotensin-converting enzyme (ACE). The levels of plasmin and plasminogen activators (uPA and tPA) and ECE-2 are reported to be reduced in AD. Reductions in neprilysin, IDE and plasmin in AD have been associated with possession of APOEepsilon4. We found no change in the level or activity of MMP-2, -3 or -9 in AD. The level and activity of ACE are increased, the level being directly related to Abeta plaque load. Up-regulation of some Abeta-degrading enzymes may initially compensate for declining activity of others, but as age, genetic factors and diseases such as hypertension and diabetes diminish the effectiveness of other Abeta-clearance pathways, reductions in the activity of particular Abeta-degrading enzymes may become critical, leading to the development of AD and CAA.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Much of the literature evidence for mechanism-based inactivation (MBI) of CYP by tricyclic antidepressants is limited to studies in rat liver microsomes. • One report from this laboratory characterized MBI of human recombinant CYP2C8 by nortriptyline. WHAT THIS STUDY ADDS • Tricyclic antidepressants form alkylamine metabolite-intermediate complexes with human recombinant CYP enzymes (expressed in Escherichia coli) relatively easily, resulting in time-dependent inhibition. • Evidence to support similar irreversible inhibition using human liver microsomal (HLM) fractions is limited. • HLM and recombinant CYP (expressed in E. coli) are not equivalent enzyme sources for evaluating the time-dependent inhibition of human drug metabolizing CYP that is associated with some drugs. AIMS To investigate time-dependent inhibition (TDI) of human drug metabolizing CYP enzymes by tricyclic antidepressants (TCAs). METHODS CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A/CYP3A4 activities were investigated following co- and preincubation with TCAs using human liver microsomes (HLM) and human recombinant CYP proteins (expressed in Escherichia coli) as the enzyme sources. A two-step incubation method was employed to examine the in vitro mechanism-based inactivation (MBI) criteria. Potential metabolite–intermediate complex (MIC) formation was studied by spectral analysis. RESULTS TCAs generally exhibited significant TDI of recombinant CYP1A2, CYP2C19 and CYP2D6 (>10% positive inhibition differences between co- and preincubation conditions). TDI of recombinant CYP2C9 was minor (