Health expenditures after first hospital admission for heart failure in Nova Scotia, Canada: a retrospective cohort study.

BACKGROUND: Although the frequency of heart failure makes it among the costliest of illnesses, there are scant Canadian data on annual costs of treatment or the costs as the condition advances. Our objective was to estimate mean prevalence- and incidence-based direct medical costs among older adults discharged alive after a first hospital admission for heart failure. METHODS: We conducted a retrospective cohort study using population-based administrative health databases for Nova Scotia. The cohort comprised persons 50 years of age or older with an incident hospital admission for heart failure between 2009 and 2012. We considered the costs (expressed as 2020 Canadian dollars) of hospital admissions, physician visits and, for patients 65 years of age or older, outpatient cardiac medications. We estimated costs for calendar years, longitudinally and in the last 2 years of life. We analyzed costs from the perspective of a third-party public payer. RESULTS: The cohort consisted of 3327 patients (mean age 77.6 yr; 1605 [48.2%] women). Median survival was 2.5 and 2.2 years among men and women, respectively. Annual prevalence-based costs were about $7100. Mean incidence-based costs ranged between $65 000 and $164 000 in the year after diagnosis and decreased by 90% subsequently. Costs were 4 to 7 times higher in the year before death than in the period from 1 to 2 years before death. INTERPRETATION: The direct medical costs of treating patients with heart failure in Nova Scotia displayed a reverse J shape, with costs highest after diagnosis, declining subsequently and then increasing during the final year of life. Strategies designed to improve the quality of care immediately after diagnosis and during more advanced stages of disease might reduce these costs.

A hierarchy of manganese competition and entry in organotypic hippocampal slice cultures.

Contrast agents improve clinical and basic research MRI. The manganese ion (Mn2+ ) is an essential, endogenous metal found in cells and it enhances MRI contrast because of its paramagnetic properties. Manganese-enhanced MRI (MEMRI) has been widely used to image healthy and diseased states of the body and the brain in a variety of animal models. There has also been some work in translating the useful properties of MEMRI to humans. Mn2+ accumulates in brain regions with high neural activity and enters cells via voltage-dependent channels that flux calcium (Ca2+ ). In addition, metal transporters for zinc (Zn2+ ) and iron (Fe2+ ) can also transport Mn2+ . There is also transfer through channels specific for Mn2+ . Although Mn2+ accumulates in many tissues including brain, the mechanisms and preferences of its mode of entry into cells are not well characterized. The current study used MRI on living organotypic hippocampal slice cultures to detect which transport mechanisms are preferentially used by Mn2+ to enter cells. The use of slice culture overcomes the presence of the blood brain barrier, which limits inferences made with studies of the intact brain in vivo. A range of Mn2+ concentrations were used and their effects on neural activity were assessed to avoid using interfering doses of Mn2+ . Zn2+ and Fe2+ were the most efficient competitors for Mn2+ uptake into the cultured slices, while the presence of Ca2+ or Ca2+ channel antagonists had a more moderate effect. Reducing slice activity via excitatory receptor antagonists was also effective at lowering Mn2+ uptake. In conclusion, a hierarchy of those agents which influence Mn2+ uptake was established to enhance understanding of how Mn2+ enters cells in a cultured slice preparation.

Optimal Usage of Sacubitril/Valsartan for the Treatment of Heart Failure: The Importance of Optimizing Heart Failure Care in Canada.

BACKGROUND: Heart failure (HF) with reduced ejection fraction represents approximately 50% of the 600,000 Canadians currently living with HF and over 90,000 new cases diagnosed each year. The angiotensin receptor neprilysin inhibitor, sacubitril/valsartan, demonstrated superior efficacy in reducing cardiovascular death and HF hospitalization over standard of care therapy. METHODS: The potential magnitude of benefit in Canada with respect to preventing or postponing deaths and reducing hospitalizations resulting from its optimal implementation in patients with HF with an ejection fraction <40% was estimated based on published sources. RESULTS: Of the potentially eligible 225,562 patients, this would amount to the prevention of 4699 cardiovascular deaths and first HF hospitalizations, 3698 thirty-day HF readmissions, and 2820 deaths due to all-cause mortality. The number of patients receiving sacubitril/valsartan nationally in 2018 was 27,267. This represents approximately 12% of the calculated eligible population for this therapy in Canada. CONCLUSIONS: The findings from this analysis suggest that a substantial number of deaths, hospitalizations, and HF readmissions could potentially be avoided by optimal usage of sacubitril/valsartan therapy in Canada. This emphasizes the importance of rapidly and appropriately implementing evidence-based medications into routine clinical practice, to achieve the best possible outcomes for our patients with HF and to reduce the high burden and cost of HF in Canada.

CONTEXTE: L'insuffisance cardiaque (IC) avec diminution de la fraction d'éjection touche actuellement environ 50 % des 600 000 Canadiens qui sont atteints d'IC, et plus de 90 000 nouveaux cas de cette affection sont diagnostiqués chaque année. L'association sacubitril-valsartan (inhibiteur de la néprilysine et antagoniste des récepteurs de l'angiotensine) a démontré une efficacité supérieure à celle du traitement de référence au chapitre de la réduction de la mortalité d'origine cardiovasculaire et des hospitalisations dues à l'IC. MÉTHODOLOGIE: L'ampleur potentielle des bienfaits du médicament au Canada en matière de prévention ou de report des décès et de réduction des hospitalisations par suite de son utilisation optimale chez les patients atteints d'IC présentant une fraction d'éjection < 40 % a été estimée sur la base de sources publiées. RÉSULTATS: Chez les 225 562 patients potentiellement admissibles au traitement, le médicament permettrait de prévenir 4 699 décès d'origine cardiovasculaire et premières hospitalisations pour cause d'IC, 3 698 réhospitalisations pour cause d'IC dans les 30 jours suivant la sortie de l'hôpital et 2 820 décès toutes causes confondues. À l'échelle nationale en 2018, 27 267 patients ont été traités par l'association sacubitril-valsartan. Cela représente environ 12 % de la population admissible au traitement selon les calculs s'appliquant au Canada. CONCLUSIONS: Les résultats de cette analyse permettent de penser que beaucoup de décès, d'hospitalisations et de réhospitalisations pour cause d'IC pourraient être évités par suite de la mise en œuvre optimale du traitement par l'association sacubitril-valsartan au Canada. Sous cet éclairage, force est de constater l'importance que revêt l'intégration rapide et appropriée des pharmacothérapies factuelles à la pratique clinique courante, dans l'optique d'une démarche visant à obtenir les meilleurs résultats possible chez nos patients atteints d'IC et à réduire le lourd fardeau de cette affection au Canada.

Impact of tissue T1 on perfusion measurement with arterial spin labeling.

PURPOSE: Arterial spin labeling (ASL) may provide quantitative maps of cerebral blood flow (CBF). Because labeled water exchanges with tissue water, this study evaluates the influence of tissue T1 on CBF quantification using ASL. METHODS: To locally modify T1 , a low dose of manganese (Mn) was intracerebrally injected in one hemisphere of 19 rats (cortex or striatum). Tissue T1 and CBF were mapped using inversion recovery and continuous ASL experiments at 4.7T. RESULTS: Mn reduced the tissue T1 by more than 30% but had little impact on other tissue properties as assessed via dynamic susceptibility and diffusion MRI. Using a single-compartment model, the use of a single tissue T1 value yielded a mean relative ipsilateral (Mn-injected) to contralateral (noninjected) CBF difference of -34% in cortex and -22% in striatum tissue. With a T1 map, these values became -7% and +8%, respectively. CONCLUSION: A low dose of Mn reduces the tissue T1 without modifying CBF. Heterogeneous T1 impacts the ASL estimate of CBF in a region-dependent way. In animals, and when T1 modifications exceed the accuracy with which the tissue T1 can be determined, an estimate of tissue T1 should be obtained when quantifying CBF with an ASL technique. Magn Reson Med 77:1656-1664, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Differential effects of amyloid-beta 1-40 and 1-42 fibrils on 5-HT1A serotonin receptors in rat brain.

Evidence accumulates suggesting a complex interplay between neurodegenerative processes and serotonergic neurotransmission. We have previously reported an overexpression of serotonin 5-HT1A receptors (5-HT(1A)R) after intrahippocampal injections of amyloid-beta 1-40 (Aß40) fibrils in rats. This serotonergic reactivity paralleled results from clinical positron emission tomography studies with [(18)F]MPPF revealing an overexpression of 5-HT(1A)R in the hippocampus of patients with mild cognitive impairment. Because Aß40 and Aß42 isoforms are found in amyloid plaques, we tested in this study the hypothesis of a peptide- and region-specific 5-HT(1A)R reactivity by injecting them, separately, into the hippocampus or striatum of rats. [(18)F]MPPF in vitro autoradiography revealed that Aß40 fibrils, but not Aß42, were triggering an overexpression of 5-HT(1A)R in the hippocampus and striatum of rat brains after 7 days. Immunohistochemical approaches targeting neuronal precursor cells, mature neurons, and astrocytes showed that Aß42 fibrils caused more pathophysiological damages than Aß40 fibrils. The mechanisms of Aß40 fibrils-induced 5-HT(1A)R expression remains unknown, but hypotheses including neurogenesis, glial expression, and axonal sprouting are discussed.

Microtubule-associated protein 6 mediates neuronal connectivity through Semaphorin 3E-dependent signalling for axonal growth.

Structural microtubule associated proteins (MAPs) stabilize microtubules, a property that was thought to be essential for development, maintenance and function of neuronal circuits. However, deletion of the structural MAPs in mice does not lead to major neurodevelopment defects. Here we demonstrate a role for MAP6 in brain wiring that is independent of microtubule binding. We find that MAP6 deletion disrupts brain connectivity and is associated with a lack of post-commissural fornix fibres. MAP6 contributes to fornix development by regulating axonal elongation induced by Semaphorin 3E. We show that MAP6 acts downstream of receptor activation through a mechanism that requires a proline-rich domain distinct from its microtubule-stabilizing domains. We also show that MAP6 directly binds to SH3 domain proteins known to be involved in neurite extension and semaphorin function. We conclude that MAP6 is critical to interface guidance molecules with intracellular signalling effectors during the development of cerebral axon tracts.

Neuronal transport defects of the MAP6 KO mouse - a model of schizophrenia - and alleviation by Epothilone D treatment, as observed using MEMRI.

The MAP6 (microtubule-associated protein 6) KO mouse is a microtubule-deficient model of schizophrenia that exhibits severe behavioral disorders that are associated with synaptic plasticity anomalies. These defects are alleviated not only by neuroleptics, which are the gold standard molecules for the treatment of schizophrenia, but also by Epothilone D (Epo D), which is a microtubule-stabilizing molecule. To compare the neuronal transport between MAP6 KO and wild-type mice and to measure the effect of Epo D treatment on neuronal transport in KO mice, MnCl2 was injected in the primary somatosensory cortex. Then, using manganese-enhanced magnetic resonance imaging (MEMRI), we followed the propagation of Mn(2+) through axonal tracts and brain regions that are connected to the somatosensory cortex. In MAP6 KO mice, the measure of the MRI relative signal intensity over 24h revealed that the Mn(2+) transport rate was affected with a stronger effect on long-range and polysynaptic connections than in short-range and monosynaptic tracts. The chronic treatment of MAP6 KO mice with Epo D strongly increased Mn(2+) propagation within both mono- and polysynaptic connections. Our results clearly indicate an in vivo deficit in neuronal Mn(2+) transport in KO MAP6 mice, which might be due to both axonal transport defects and synaptic transmission impairments. Epo D treatment alleviated the axonal transport defects, and this improvement most likely contributes to the positive effect of Epo D on behavioral defects in KO MAP6 mice.

Impact of manganese on primary hippocampal neurons from rodents.

Manganese-enhanced magnetic resonance imaging (MEMRI) is a powerful tool for in vivo tract tracing or functional imaging of the central nervous system. However Mn(2+) may be toxic at high levels. In this study, we addressed the impact of Mn(2+) on mouse hippocampal neurons (HN) and neuron-like N2a cells in culture, using several approaches. Both HN and N2a cells not exposed to exogenous MnCl2 were shown by synchrotron X-ray fluorescence to contain 5 mg/g Mn. Concentrations of Mn(2+) leading to 50% lethality (LC50) after 24 h of incubation were much higher for N2a cells (863 mM) than for HN (90 mM). The distribution of Mn(2+) in both cell types exposed to Mn(2+) concentrations below LC50 was perinuclear whereas that in cells exposed to concentrations above LC50 was more diffuse, suggesting an overloading of cell storage/detoxification capacity. In addition, Mn(2+) had a cell-type and dose-dependent impact on the total amount of intracellular P, Ca, Fe and Zn measured by synchrotron X-ray fluorescence. For HN neurons, immunofluorescence studies revealed that concentrations of Mn(2+) below LC50 shortened neuritic length and decreased mitochondria velocity after 24 h of incubation. Similar concentrations of Mn(2+) also facilitated the opening of the mitochondrial permeability transition pore in isolated mitochondria from rat brains. The sensitivity of primary HN to Mn(2+) demonstrated here supports their use as a relevant model to study Mn(2+) -induced neurotoxicity.

Synthesis and biological evaluation in rat and cat of [18F]12ST05 as a potential 5-HT6 PET radioligand.

INTRODUCTION: 5-hydroxytryptamine (5-HT)6 receptors represent one of the more recently discovered serotoninergic receptor family. However, no 5-HT6 positron emission tomography (PET) radiotracer is currently used in clinical imaging studies. The purpose of this study was to propose the first fluorinated PET radiotracer for this brain receptor. METHODS: A new compound presenting in vitro high affinity towards the serotoninergic 5-HT6 receptor, N-[2-(1-[(4-fluorophenyl)sulfonyl]-1H-indol-4-yloxy)ethyl]-N,N-dimethylamine, was labelled with fluorine 18 via a nitro-/fluoronucleophilic substitution. Biological evaluations included (i) in vitro and ex vivo autoradiographies in rat brain and (ii) a PET scan on anaesthetized cat. RESULTS AND CONCLUSION: Although the radioligand showed excellent brain penetration, it did not reveal any specific binding to the 5-HT6 receptors indicating that this radiotracer is not suitable for mapping 5-HT6 receptors using PET.