An Insertion Within SIRPβ1 Shows a Dual Effect Over Alzheimer's Disease Cognitive Decline Altering the Microglial Response

Background

Microglial dysfunction plays a causative role in Alzheimer's disease (AD) pathogenesis. Here we focus on a germline insertion/deletion variant mapping SIRPβ1, a surface receptor that triggers amyloid-β(Aβ) phagocytosis via TYROBP.

Objective

To analyze the impact of this copy-number variant in SIRPβ1 expression and how it affects AD molecular etiology.

Methods

Copy-number variant proxy rs2209313 was evaluated in GERALD and GR@ACE longitudinal series. Hippocampal specimens of genotyped AD patients were also examined. SIRPβ1 isoform-specific phagocytosis assays were performed in HEK393T cells.

Results

The insertion alters the SIRPβ1 protein isoform landscape compromising its ability to bind oligomeric Aβ and its affinity for TYROBP. SIRPβ1 Dup/Dup patients with mild cognitive impairment show an increased cerebrospinal fluid t-Tau/Aβ ratio (p = 0.018) and a higher risk to develop AD (OR = 1.678, p = 0.018). MRIs showed that Dup/Dup patients exhibited a worse initial response to AD. At the moment of diagnosis, all patients showed equivalent Mini-Mental State Examination scores. However, AD patients with the duplication had less hippocampal degeneration (p < 0.001) and fewer white matter hyperintensities. In contrast, longitudinal studies indicate that patients bearing the duplication allele show a slower cognitive decline (p = 0.013). Transcriptional analysis also shows that the SIRPβ1 duplication allele correlates with higher TREM2 expression and an increased microglial activation.

Conclusions

The SIRPβ1 internal duplication has opposite effects over MCI-to-Dementia conversion risk and AD progression, affecting microglial response to Aβ. Given the pharmacological approaches focused on the TREM2-TYROBP axis, we believe that SIRPβ1 structural variant might be considered as a potential modulator of this causative pathway.

The Performance Diagnostic Checklist-Human Services (1.1): An initial assessment of validity and reliability

The Performance Diagnostic Checklist-Human Services (PDC-HS) is an assessment used to identify variables contributing to staff performance concerns in human-service settings. In the current study, we introduce and assess the test validity, interrater reliability, and test-retest reliability of the PDC-HS (1.1), a revised version of the assessment that included revised instructions, questions, and intervention planning references. We measured the psychometric properties of the revised assessment by analyzing answers obtained from watching video vignettes of simulated interviews between consultants and a supervisor. Twenty-one participants watched the vignettes and completed the PDC-HS (1.1) based on the answers provided during the interview. We also included an item analysis to identify questions on which participants made errors and an intervention selection task to assess whether participants selected an appropriate intervention to target the indicated domain. The results support the use of the PDC-HS (1.1) in human services settings.

Extended Sentinel Monitoring of Helicoverpa zea Resistance to Cry and Vip3Aa Toxins in Bt Sweet Corn: Assessing Changes in Phenotypic and Allele Frequencies of Resistance

Transgenic corn and cotton that produce Cry and Vip3Aa toxins derived from Bacillus thuringiensis (Bt) are widely planted in the United States to control lepidopteran pests. The sustainability of these Bt crops is threatened because the corn earworm/bollworm, Helicoverpa zea (Boddie), is evolving a resistance to these toxins. Using Bt sweet corn as a sentinel plant to monitor the evolution of resistance, collaborators established 146 trials in twenty-five states and five Canadian provinces during 2020-2022. The study evaluated overall changes in the phenotypic frequency of resistance (the ratio of larval densities in Bt ears relative to densities in non-Bt ears) in H. zea populations and the range of resistance allele frequencies for Cry1Ab and Vip3Aa. The results revealed a widespread resistance to Cry1Ab, Cry2Ab2, and Cry1A.105 Cry toxins, with higher numbers of larvae surviving in Bt ears than in non-Bt ears at many trial locations. Depending on assumptions about the inheritance of resistance, allele frequencies for Cry1Ab ranged from 0.465 (dominant resistance) to 0.995 (recessive resistance). Although Vip3Aa provided high control efficacy against H. zea, the results show a notable increase in ear damage and a number of surviving older larvae, particularly at southern locations. Assuming recessive resistance, the estimated resistance allele frequencies for Vip3Aa ranged from 0.115 in the Gulf states to 0.032 at more northern locations. These findings indicate that better resistance management practices are urgently needed to sustain efficacy the of corn and cotton that produce Vip3Aa.

Monocyte-derived cells invade brain parenchyma and amyloid plaques in human Alzheimer's disease hippocampus

Microglia are brain-resident myeloid cells and play a major role in the innate immune responses of the CNS and the pathogenesis of Alzheimer's disease (AD). However, the contribution of nonparenchymal or brain-infiltrated myeloid cells to disease progression remains to be demonstrated. Here, we show that monocyte-derived cells (MDC) invade brain parenchyma in advanced stages of AD continuum using transcriptional analysis and immunohistochemical characterization in post-mortem human hippocampus. Our findings demonstrated that a high proportion (60%) of demented Braak V-VI individuals was associated with up-regulation of genes rarely expressed by microglial cells and abundant in monocytes, among which stands the membrane-bound scavenger receptor for haptoglobin/hemoglobin complexes or Cd163. These Cd163-positive MDC invaded the hippocampal parenchyma, acquired a microglial-like morphology, and were located in close proximity to blood vessels. Moreover, and most interesting, these invading monocytes infiltrated the nearby amyloid plaques contributing to plaque-associated myeloid cell heterogeneity. However, in aged-matched control individuals with hippocampal amyloid pathology, no signs of MDC brain infiltration or plaque invasion were found. The previously reported microglial degeneration/dysfunction in AD hippocampus could be a key pathological factor inducing MDC recruitment. Our data suggest a clear association between MDC infiltration and endothelial activation which in turn may contribute to damage of the blood brain barrier integrity. The recruitment of monocytes could be a consequence rather than the cause of the severity of the disease. Whether monocyte infiltration is beneficial or detrimental to AD pathology remains to be fully elucidated. These findings open the opportunity to design targeted therapies, not only for microglia but also for the peripheral immune cell population to modulate amyloid pathology and provide a better understanding of the immunological mechanisms underlying the progression of AD.

AV synchronous pacing in patients implanted with leadless pacemakers: a real-world cohort study

Funding Acknowledgements

Type of funding sources: None.

Backgroung

Leadless pacemakers (LPM) were developed to overcome complications related to endovenous devices. Devices carrying an accelerometer-based atrial sensing algorithm provided good AV synchrony in a 5-hours study.

Methods

Prospective study of patients implanted with LPM capable of AV synchronous pacing at our institution. We performed a close follow-up consisting of device check-ups 24 h after the implant and 1-3-6-12 months later. Changes in programming were guided by device counters and rate histograms. Once AV synchrony derived from counters (AM-VP + AM-VS) remained stable for at least two consecutive months, a 24 hours Holter monitoring was performed. ECG recordings were automatically and blindly analyzed with a delineation system based on the wavelet transform developed by Martinez et al.1 Cardiac cycles were defined as synchronous if a ventricular event followed the P-wave by ≤300 ms. AV synchrony was calculated by dividing the number of synchronous cycles by the total number of cardiac cycles.

Our aim was to describe AV synchrony in a real-world setting and to determine which echocardiographic and programming parameters were related to optimal AV synchrony (≥85% of total cardiac cycles).

Results

A total of 18 patients (12 males, mean age 82.6 ±8.1) were included. Indications for pacing were complete AV block (n=10) and second-degree AV block (n=8). Device reprogramming was needed in all patients at follow-up. The 24 h Holter monitoring was performed 118.8±43.8 days after the implant. Implant data and, device settings and programming at Holter date is displayed in Table 1. One patient was excluded from the analysis due to the development of severe sinus node disease. Total ECG recorded time was 386.8 hours and 1,537,995 cardiac cycles were analyzed.

Median AV synchrony, after Holter monitoring analysis, was 88.2% (interquartile range 79.9-95,1%) and 12 out of 17 patients showed an AV synchrony ≥85% of cardiac cycles. Optimal AV synchrony was related to smaller right atrium size (13.2±3.4 cm2 vs 15.6±1.2 cm2 for AV synchrony ≥85 and &lt;85%, respectively) but no association appeared between diastolic parameters (E, A, E/A ratio, E´, A´) and AV synchrony. Rate smoothing algorithm was associated with higher rates of optimal AV synchrony (81.8% of patients with algorithm OFF vs 50% of patients activated). Besides, higher A3 threshold (7.1±3.5 m/s2 vs 4.2 ± 1.1 m/s2) and longer A3 window (620.8±25.7 ms vs 600 ms for AV synchrony ≥85% and &lt;85%, respectively) were also linked to optimal AV synchrony. Multivariate analysis did not show any independent predictor of AV synchrony.

Conclusions

In our cohort of LPM patients we obtained high percentages of AV synchronous pacing in a real-life setting. Device reprogramming was often needed, and larger studies are desirable to confirm our data.

Aβ oligomers trigger necroptosis-mediated neurodegeneration via microglia activation in Alzheimer's disease

Alzheimer’s disease (AD) is a major adult-onset neurodegenerative condition with no available treatment. Compelling reports point amyloid-β (Aβ) as the main etiologic agent that triggers AD. Although there is extensive evidence of detrimental crosstalk between Aβ and microglia that contributes to neuroinflammation in AD, the exact mechanism leading to neuron death remains unknown. Using postmortem human AD brain tissue, we show that Aβ pathology is associated with the necroptosis effector pMLKL. Moreover, we found that the burden of Aβ oligomers (Aβo) correlates with the expression of key markers of necroptosis activation. Additionally, inhibition of necroptosis by pharmacological or genetic means, reduce neurodegeneration and memory impairment triggered by Aβo in mice. Since microglial activation is emerging as a central driver for AD pathogenesis, we then tested the contribution of microglia to the mechanism of Aβo-mediated necroptosis activation in neurons. Using an in vitro model, we show that conditioned medium from Aβo-stimulated microglia elicited necroptosis in neurons through activation of TNF-α signaling, triggering extensive neurodegeneration. Notably, necroptosis inhibition provided significant neuronal protection. Together, these findings suggest that Aβo-mediated microglia stimulation in AD contributes to necroptosis activation in neurons and neurodegeneration. As necroptosis is a druggable degenerative mechanism, our findings might have important therapeutic implications to prevent the progression of AD.

Increased severity in SARS-CoV-2 infection of minorities in Spain

Introduction

With the global spread of COVID-19, studies in the US and UK have shown that certain communities have been strongly impacted by COVID-19 in terms of incidence and mortality. The objective of the study was to determine social determinants of health among COVID-19 patients hospitalized in the two major cities of Spain.

Material and methods

A multicenter retrospective case series study was performed collecting administrative databases of all COVID-19 patients ≥18 years belonging to two centers in Madrid and two in Barcelona (Spain) collecting data from 1^st March to 15th April 2020. Variables obtained age, gender, birthplace and residence ZIP code. From ZIP code we obtained per capita income of the area. Predictors of the outcomes were explored through generalized linear mixed-effects models, using center as random effect.

Results

There were 5,235 patients included in the analysis. After multivariable analysis adjusted by age, sex, per capita income, population density, hospital experience, center and hospital saturation, patients born in Latin American countries were found to have an increase in ICU admission rates (OR 1.56 [1.13-2.15], p<0.01) but no differences were found in the same model regarding mortality (OR 1.35 [0.95-1.92], p=0.09).

Conclusions

COVID-19 severity varies widely, not only depending on biological but also socio-economic factors. With the emerging evidence that this subset of population is at higher risk of poorer outcomes, targeted public health strategies and studies are needed.

Plaque-Associated Oligomeric Amyloid-Beta Drives Early Synaptotoxicity in APP/PS1 Mice Hippocampus: Ultrastructural Pathology Analysis

Alzheimer’s disease (AD) is a devastating neurodegenerative disorder characterized by initial memory impairments that progress to dementia. In this sense, synaptic dysfunction and loss have been established as the pathological features that best correlate with the typical early cognitive decline in this disease. At the histopathological level, post mortem AD brains typically exhibit intraneuronal neurofibrillary tangles (NFTs) along with the accumulation of amyloid-beta (Abeta) peptides in the form of extracellular deposits. Specifically, the oligomeric soluble forms of Abeta are considered the most synaptotoxic species. In addition, neuritic plaques are Abeta deposits surrounded by activated microglia and astroglia cells together with abnormal swellings of neuronal processes named dystrophic neurites. These periplaque aberrant neurites are mostly presynaptic elements and represent the first pathological indicator of synaptic dysfunction. In terms of losing synaptic proteins, the hippocampus is one of the brain regions most affected in AD patients. In this work, we report an early decline in spatial memory, along with hippocampal synaptic changes, in an amyloidogenic APP/PS1 transgenic model. Quantitative electron microscopy revealed a spatial synaptotoxic pattern around neuritic plaques with significant loss of periplaque synaptic terminals, showing rising synapse loss close to the border, especially in larger plaques. Moreover, dystrophic presynapses were filled with autophagic vesicles in detriment of the presynaptic vesicular density, probably interfering with synaptic function at very early synaptopathological disease stages. Electron immunogold labeling showed that the periphery of amyloid plaques, and the associated dystrophic neurites, was enriched in Abeta oligomers supporting an extracellular location of the synaptotoxins. Finally, the incubation of primary neurons with soluble fractions derived from 6-month-old APP/PS1 hippocampus induced significant loss of synaptic proteins, but not neuronal death. Indeed, this preclinical transgenic model could serve to investigate therapies targeted at initial stages of synaptic dysfunction relevant to the prodromal and early AD.

Validation of leadless atrioventricular synchronous pacing with Holter-ECG: a pilot study

Background

The novel MICRA AV leadless pacemaker can provide atrioventricular (AV) synchronous pacing using an accelerometer-based atrial sensing algorithm.

Purpose

To describe the performance of MICRA AV pacemaker in a real-life setting and to determine the agreement between AV synchrony determined by the device counters and AV synchrony obtained by a 24 h ECG Holter test.

Methods

This pilot study included the first ten patients implanted with a MICRA AV leadless pacemaker at our institution. All implants were performed according to standard protocols and under deep sedation. A close follow-up was performed, and atrial sensing parameters were adjusted following AV synchrony given by the device counters. Patients underwent a 24 h ECG Holter test once AV synchrony remained stable for at least two months. The ECG Holter signal was analyzed in a blinded manner by an automatic delineation system based on the wavelet transform (Figure). This algorithm has a sensivity of 98.9% and a positive predictive value of 91.9% to detect p waves. Cardiac cycles were defined as synchronous if a QRS complex followed the P-wave by ≤300 ms, according to MARVEL 2 study criterion. AV synchrony obtained from the 24 h Holter test was compared with AV synchrony extracted from the device counters (AM-VP + AM-VS) during the same 24 h.

Results

From June to November 2020, 10 patients (7 males, mean age 83.5±5.4) were implanted with a MICRA AV leadless pacemaker (5 patients due to complete AV block and 5 patients due to second degree AV block). All devices were implanted after 1 deployment and no major complications appeared. Data related to implant parameters are displayed in Table 1. Device reprogramming was needed in all patients during follow-up. The 24 h ECG Holter monitoring was performed 141.4±45 days after the implant (mean time). Device settings and programming at Holter date is displayed in Table 1. Total ECG recorded time was 210.6 h and 915,488 cardiac cycles were analyzed. The mean percentage of synchronous cardiac cycles was 88.6±8.5% of total cycles while the mean AV synchrony determined by the device counters (AM-VP + AM-VS) during those 24 h was 89.8±5.5%. A good patient to patient correlation between these two measures was found (coefficient of intraclass correlation = 0.72).

Conclusions

We obtained high rates of AV synchrony with MICRA AV leadless pacemaker, in our short-term follow-up pilot study. Manual adjustment of the atrial sensing parameters, guided by the device counters, seems to be useful to obtain an optimal performance.

Funding Acknowledgement

Type of funding sources: None.

Should We Open Fire on Microglia? Depletion Models as Tools to Elucidate Microglial Role in Health and Alzheimer's Disease

Microglia play a critical role in both homeostasis and disease, displaying a wide variety in terms of density, functional markers and transcriptomic profiles along the different brain regions as well as under injury or pathological conditions, such as Alzheimer's disease (AD). The generation of reliable models to study into a dysfunctional microglia context could provide new knowledge towards the contribution of these cells in AD. In this work, we included an overview of different microglial depletion approaches. We also reported unpublished data from our genetic microglial depletion model, Cx3cr1CreER/Csf1rflx/flx, in which we temporally controlled microglia depletion by either intraperitoneal (acute model) or oral (chronic model) tamoxifen administration. Our results reported a clear microglial repopulation, then pointing out that our model would mimic a context of microglial replacement instead of microglial dysfunction. Next, we evaluated the origin and pattern of microglial repopulation. Additionally, we also reviewed previous works assessing the effects of microglial depletion in the progression of Aβ and Tau pathologies, where controversial data are found, probably due to the heterogeneous and time-varying microglial phenotypes observed in AD. Despite that, microglial depletion represents a promising tool to assess microglial role in AD and design therapeutic strategies.

Combination anti-coronavirus therapies based on nonlinear mathematical models

Using nonlinear mathematical models and experimental data from laboratory and clinical studies, we have designed new combination therapies against COVID-19.

Amyloid-β impairs the phagocytosis of dystrophic synapses by astrocytes in Alzheimer's disease

Reactive astrocytes and dystrophic neurites, most aberrant presynaptic elements, are found surrounding amyloid-β plaques in Alzheimer's disease (AD). We have previously shown that reactive astrocytes enwrap, phagocytose, and degrade dystrophic synapses in the hippocampus of APP mice and AD patients, but affecting less than 7% of dystrophic neurites, suggesting reduced phagocytic capacity of astrocytes in AD. Here, we aimed to gain insight into the underlying mechanisms by analyzing the capacity of primary astrocyte cultures to phagocytose and degrade isolated synapses (synaptoneurosomes, SNs) from APP (containing dystrophic synapses and amyloid-β peptides), Tau (containing AT8- and AT100-positive phosphorylated Tau) and WT (controls) mice. We found highly reduced phagocytic and degradative capacity of SNs-APP, but not AT8/AT100-positive SNs-Tau, as compared with SNs-WT. The reduced astrocyte phagocytic capacity was verified in hippocampus from 12-month-old APP mice, since only 1.60 ± 3.81% of peri-plaque astrocytes presented phagocytic structures. This low phagocytic capacity did not depend on microglia-mediated astrocyte reactivity, because removal of microglia from the primary astrocyte cultures abrogated the expression of microglia-dependent genes in astrocytes, but did not affect the phagocytic impairment induced by oligomeric amyloid-β alone. Taken together, our data suggest that amyloid-β, but not hyperphosphorylated Tau, directly impairs the capacity of astrocytes to clear the pathological accumulation of oligomeric amyloid-β, as well as of peri-plaque dystrophic synapses containing amyloid-β, perhaps by reducing the expression of phagocytosis receptors such as Mertk and Megf10, thus increasing neuronal damage in AD. Therefore, the potentiation or recovery of astrocytic phagocytosis may be a novel therapeutic avenue in AD.

36,269 patients with chronic cardiovascular, metabolic and renal conditions: impact on clinical outcomes, medical resource use and health-related costs of deranged serum potassium levels

Background

Chronic Heart Failure (CHF) and its risk factors at stage A of the disease are conditions that trends to facilitate potassium (K+) derangements, for pathophysiology mechanisms and medication use than could facilitate both hyper- and hypokalamia. Studies on the associations between potassium derangements and clinical outcomes in these patient populations have yielded mixed findings, and the implications for healthcare expenditure are unknown.

Purpose

The objectives of our analysis was to asses the population-based associations between hyperkalemia, hypokalemia (compared to normokalemia) and all-cause death, urgent hospitalization, emergency department visits, daycare visits, and a yearly healthcare expenditure &gt;85th percentile, in patients with chronic heart failure, chronic kidney disease, diabetes mellitus, hypertension and ischemic heart disease.

Methods

Population-based, longitudinal study including up to 36,269 patients from the Public Healthcare Area with at least one of those conditions. We used three linked administrative, hospital and primary care healthcare databases with exhaustive information on sociodemographics, medical diagnoses, pharmacy dispensing and laboratory data. Participants were identified and followed between 2015 and 2017, had to be ≥55 years old and have at least one serum potassium measurement recorded; and were classified as hyperkalemic, hypokalemic or normokalemic. Four analytic designs were used to evaluate prevalent and incident disease cases as well as prevalent and incident use of renin-angiotensin-aldosterone system inhibitors

Results

The majority of study participants remained normokalemic during the 3 months following study entry (ranging 94%–96%) and hyperkalemia was twice as frequent as hypokalemia. In all analyses, compared to normokalemic patients those with hyperkalemia had a worse crude event-free survival for all endpoints, and the worst survival was observed for hypokalemic patients [see Figure 1: prevalent case analysis; Kaplan-Meier cumulative survivor function curves for all-cause death (upper left), hospitalization (upper right), ED visits (lower left) and daycare visits (lower right)].

In multivariable-adjusted analyses, hyperkalemia was robustly and significantly associated with an increased risk of all-cause death (hazard ratios from Cox regression models ranging 1.31–1.68) and with an increased odds of a yearly healthcare expenditure &gt;85th percentile (odds ratios 1.21–1.29). Associations were even stronger in hypokalemic patients (hazard ratios for all-cause death 1.92–2.60; odds ratios for healthcare expenditure &gt;percentile 85th 1.81–1.85).

Conclusions

Experimental studies are needed to confirm whether prevention of potassium derangements reduces mortality and healthcare expenditure in patients with these chronic conditions. Until then, our findings provide further observational evidence on the potential importance of maintaining normal potassium levels in this setting.

Figure 1

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): The present study was funded by an unrestricted research grant from Vifor Pharma.

Double check discharge planning to improve the results of a heart failure programme

Background

Reduction of readmissions in heart failure (HF) patients is a main goal of HF programmes. Establishing a discharge planning for the patient and coordinating it with primary care teams are key aspects for their success.

Purpose

Evaluate whether a double check discharge planning based on adding face-to-face joint weekly sessions with primary care managers to the conventional electronic communication of care plan reduces 6-month readmission and 6-month mortality.

Methods

We evaluated all patients discharged from hospital with HF as primary diagnosis between September 2017 and January 2019. We compared outcomes between patients discharged during Period #1 (single check; September 2017 - April 2018) and those discharged during Period #2 (double check; May 2018 - January 2019).

Primary endpoint was the combined endpoint of all-cause death or all-cause hospitalization 6 months after discharge from the index hospitalization.

Results

The study enrolled 317 patients: 182 in Period #1 and 135 in Period #2.

Mean age was 76±9 years. There was a higher proportion of patients with diabetes and COPD in Period #1, with no differences in other baseline characteristics.

The combined endpoint of all cause-death and all-cause hospitalization at 6 months was significantly reduced in patients in the double check discharge planning group (27% vs. 16%, p 0.021).

Conclusions

In a HF programme, the addition of a double check discharge planning based on having joint weekly sessions with primary care managers on top of the conventional electronic communication of care plan reduces 6-month readmission and 6-month mortality.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Hospital Universitari de Bellvitge

Effectiveness of nurse-led hospital-based heart failure programmes in octagenarians and nonagenarians: is age important?

Background

Efficacy of HF programmes in oldest old (octogenarians and nonagenarians) has not been fully explored.

Methods

We conducted a natural experiment evaluating all patients after hospitalization for heart failure as primary diagnosis between January 2017 and January 2019. We compared outcomes between patients discharged during Period #1, before the implementation of the program with patients discharged during Period #2, after the implementation of the 7-step bundle of interventions. We explored the interaction between age group (&lt;80 vs. ≥80 years old) by the intervention modality (HF programme vs. usual care). Primary end-point was the combined end-point of all-cause death or all-cause hospitalization at 6 months after discharge from the index hospitalization.

Results

The study enroled 440 patients. Mean age of the whole cohort was 75±9 years. In the oldest old subgroup (n=160), mean age was 84±3. No differences were found in baseline characteristics of patients between usual care and HF program. 30-day all-cause readmission was significantly reduced in patients in the HF programme group compared to patients in the usual care group in both age strata. In unadjusted Cox regression analyses in the oldest old group, management of patients in the HF programme was significanty associated with a reduction in the risk of the primary end-point (HR: 0.50; 95% CI [0.29–0.85]; p=0.011).

Conclusions

Management of patients in a nurse-led integrated care-based heart failure programme results in reduction of all-cause death or all-cause hospitalizations in oldest old patients.

Event-free survival cumulative curves.

Funding Acknowledgement

Type of funding source: None

Epidemiology of potassium derangements among chronic cardiovascular, metabolic and renal conditions: a population-based analysis data from more than 375,000 individuals

Introduction

In patients with chronic cardiovascular, metabolic and renal disorders, potassium (K)+ homeostasis is often delicate, especially in the presence of renin-angiotensin-aldosterone system inhibition (RAASI) and/or diuretic therapies. In this context, current clinical practical guidelines for the management of these patients recommend close monitoring of renal function and K+ levels, particularly in the presence of drug titration. Nevertheless, very limited epidemiological data on their importance at a population level is available.

Purpose

The objectives of the present analysis are to estimate the prevalence of potassium (K+) derangements in five key chronic cardiovascular, metabolic and renal conditions at the population level, its use of RAASI medication and describe potassium derangements among RAASI users.

Methods

We used data from more than 375,000 individuals 55 years of age or older included in the population-based healthcare database of a public Institute of Health between 2015 and 2017. The conditions of interest were chronic heart failure (CHF), chronic kidney disease (CKD), diabetes mellitus (DM), ischemic heart disease (IHD), and hypertension (HTN). RAASI medications included angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, mineralocorticoid receptor antagonists (MRAs), and rennin inhibitors. Hyperkalemia was defined as K+ levels &gt;5.0 mEq/L and hypokalemia as K+ &lt;3.5 mEq /L

Results

The prevalence of chronic cardiovascular, metabolic and renal conditions was high, particularly of HTN (48.2–48.9%). The prevalence of hyperkalemia was ranging between 10% and 25% depending of the condition, more frequent in CKD and less frequent in HTN patients. In figure, we display the prevalence of hyperkalemia among individuals with each of the relevant chronic conditions, January 1st, 2016 and January 1st, 2017. Use of at least one RAASI medication was very prevalent in HTN patients (75.2–77.3%). Among RAASI users, the frequency of K+ derangements and mainly of hyperkalemia was very noticeable (12% overall), especially in patients with CKD, CHF, elderly individuals, and users of MRAs. Hypokalemia was less frequent (1%).

Conclusion

The high prevalence of K+ derangements and predominantly hyperkalemia among RAASI users highlights the real-world relevance of K+ derangements and the importance of close monitoring and management of K+ levels in routine clinical practice. This is likely to benefit a large number of patients, particularly those at higher risk.

Figure 1. Prevalence of hyperkalemia

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Josep Comin-Colet and Miguel Cainzos-Achirica have participated in other research projects funded by unrestricted grants from Vifor Pharma

Psychosocial and clinical factors associated with poor self-care in patients with chronic heart failure

Background

Self care is a crucial factor in the education of patients with heart failure (HF) and directly impacts in the progression of the disease.

Beyond heart failure related factors, the role of psychosocial determinants and its interaction with clinical aspects has not been fully explored.

Aims

The aim of the study was to analyze both clinical and psychosocial factors associated with poor self care in patients with chronic HF.

Methods

Self care was evaluated at baseline with the 9 item European HFR Self Care Behaviour Scale (9 item ESCBS).

Scores were standardized and reversed from 0 (worst self care) to 100 (better self care). This study we analysed the associations between poor self care (defined as scores in the lower tertile of the 9 item ESCBS) with demographic, HF-related (clinical) and psychosocial factors in all patients at baseline.

Results

We included 1123 patients: mean age 72±11, 639 (60%) were male, mean LVEF 45±17 and 454 (40%) were in NYHA class III or IV. Mean score of the 9-item ESCBS was 69±28. In the clinical multivariate analyses HF-related factors associated with poor self-care were serum albumins level, ckd level and previous admission due to heart failure. In the psychosocial multivariate analyses poor social support, depressive symptoms and needing a caregiver were independently associated with poor self care. In combined models, only psychosocial factors were independently associated with poor self care whereas no clinical factors remain in the model.

Conclusion

Our study showed that psychosocial conditions are the main factors independently associated with poor self-care in patients with chronic heart failure

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Hospital del Bellvitge

Association between self-care and prognosis in 1123 patients with chronic heart failure

Background

Self-care is a crucial factor in the education of patients with heart failure (HF) and directly impacts in the progression of the disease. However, little is published about its major clinical implications as admission or mortality in patients with HF.

Aims and methods

The aim of the study was to analyze time to admission due to acute heart failure and mortality associated with poor self-care in patients with chronic HF.

We prospectively recruited consecutive patients with stable chronic HF referred to a nurse-led HF programme. Selfcare was evaluated at baseline with the 9 item European Heart Failure Self-Care Behavior Scale. Scores were standardized and reversed from 0 (worst selfcare) to 100 (better self care). For the purpose of this study we analyzed the associations of worse self-care (defined as scores below the lower tertile of the scale) with demographic, disease-related (clinical) and psychosocial factors in all patients at baseline.

Results

We included 1123 patients, mean age 72±11, 639 (60%) were male, mean LVEF 45±17 and 454 (40,4%) were in NYHA class III or IV. Mean score of the 9-item ESCBE was 69±28. Score below 55 (lower tertile) defined impaired selfcare behaviour.

Those patients with worse self-care had more ischaemic heart disease, more COPD, and they achieved less distance in the 6 minute walking test. Regarding psychosocial items patients in lower tertile of self-care needed a caregiver more frequently, they present more cognitive impairment, depressive symptoms and worse score in terms of health self-perception.

Multivariate Cox Models showed that a score below 55 points in 9-item ESCBE was independently associated with higher readmission due to acute heart failure [HR 1.26 (1.02–1.57), p value=0.034] and with mortality [HR 1.24 CI95% (1.02–1.50), p value=0.028]

Conclusion

Poor self-care measured with the modified 9-item ESCBE was associated with higher risk of admission due to acute decompensation and higher risk of mortality in patients with chronic heart failure.

These results highlight the importance of assessing self-care and provide measures to improve them.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Hospital Univesitario de Bellvitge

A population-based analysis in 375,233 cases of heart failure stages A, B and C. Real world epidemiology of prevalence and temporal trends in South-European populations

Background

Prevalence of congestive heart failure (CHF) and predisposing conditions has described previously. Most of these studies evaluated centre-European or north-American populations. However, the prevalence and evolutionary changes of Heart Failure stages A, B and C has not been fully elucidated in Mediterranean cohorts.

Purpose

To estimate the prevalence of CHF (HF Stage C) and four additional key chronic cardiovascular, metabolic and renal conditions predisposing to the development of CHF (HF Stages A and B) at a population level in a south-European healthcare area. We analysed the evolutionary changes in the prevalence in these five conditions.

Methods

In a healthcare area of 1,3Millions inhabitants, we extracted health related information of all individuals ≥55 years old. We analysed data of 375,233 individuals included in the population-based healthcare database of a public Institute of Health between 2015 and 2017. The conditions of interest were CHF, chronic kidney disease (CKD), diabetes mellitus (DM), ischemic heart disease (IHD) and hypertension (HTN).

Results

The prevalence of chronic conditions was high, particularly of HTN (48.2–48.9%) and DM individuals (14.6–14.8%). The other conditions were less frequent, with prevalence around 2–4% for IHD, 5–9% for CKD and 2–4% for CHF (Table). However, the less frequent conditions had a striking upward trend with over 1,500 new prevalent cases per year between 2015 and 2017 for CHF (45% relative increase), more than 2,500 new prevalent cases for IHD (67% relative increase) and more than 4,000 new prevalent cases per year for CKD (44% relative increase).

Conclusion

In this south European cohort, there were a high prevalence of HTN and DM as risk factors and a significant trend of increasing prevalence in high cost chronic conditions such as CHF, IHD and CKD.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): The present study was funded by an unrestricted research grant from Vifor Pharma.

Long-term effectiveness of a nurse-led 7-step transitional intervention programme in heart failure

Background

Reduction of 30-day readmission in heart failure (HF) patients is a main goal of health-care systems. Programmes to decrease 30-day readmission have successfully reduced it but have failed to neither maintain benefit afterwards nor decrease mortality. Moreover, in many cases the price of reducing 30-day readmission is a mortality increase.

Purpose

Evaluate whether the impact of a fully nurse-led HF programme directed to reduce 30-day readmission and mortality extends to longer periods of time, including 90 days and 180 days after discharge.

Methods

We evaluated all patients discharged from hospital with HF as primary diagnosis between January 2017 and January 2019. We compared outcomes between patients discharged during Period #1 (pre-programme; Jan 2017 - Aug 2017) and those discharged during Period #2 (HF programme; Sept 2017 - Jan 2019).

Primary endpoint was the combined endpoint of all-cause death or all-cause hospitalization 90 days and 180 days after discharge from the index hospitalization.

Results

The study enrolled 440 patients: 123 in Period #1 and 317 in Period #2.

Mean age was 75±9 years. There was a higher proportion of female patients in Period #2 (38.2% vs 26.8%, p=0.025), with no differences in other baseline characteristics.

The combined endpoint of all cause-death and all-cause hospitalization was significantly reduced in patients in the HF programme group, both at 90 days [OR 0.37 (0.22–0.63), p&lt;0.001] and at 180 days [OR 0.27 (CI 0.17–0.43), p&lt;0.001]. Such a decrease was at expense of a reduction in cardiovascular (CV) hospitalization and HF hospitalization.

There were no differences between groups in mortality [OR 0.96 (0.18–5.00), p=0.293].

Conclusions

A fully nurse-led HF programme reduces the combined endpoint of all-cause death and all-cause hospitalization both at 90 days and 180 days after an index discharge for HF.

Such a decrease is driven by a reduction of CV and HF hospitalization, which are maintained over time. There were no differences between groups in mortality.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Hospital Universitari de Bellvitge

Enhancing microtubule stabilization rescues cognitive deficits and ameliorates pathological phenotype in an amyloidogenic Alzheimer's disease model

In Alzheimer's disease (AD), and other tauopathies, microtubule destabilization compromises axonal and synaptic integrity contributing to neurodegeneration. These diseases are characterized by the intracellular accumulation of hyperphosphorylated tau leading to neurofibrillary pathology. AD brains also accumulate amyloid-beta (Aβ) deposits. However, the effect of microtubule stabilizing agents on Aβ pathology has not been assessed so far. Here we have evaluated the impact of the brain-penetrant microtubule-stabilizing agent Epothilone D (EpoD) in an amyloidogenic model of AD. Three-month-old APP/PS1 mice, before the pathology onset, were weekly injected with EpoD for 3 months. Treated mice showed significant decrease in the phospho-tau levels and, more interesting, in the intracellular and extracellular hippocampal Aβ accumulation, including the soluble oligomeric forms. Moreover, a significant cognitive improvement and amelioration of the synaptic and neuritic pathology was found. Remarkably, EpoD exerted a neuroprotective effect on SOM-interneurons, a highly AD-vulnerable GABAergic subpopulation. Therefore, our results suggested that EpoD improved microtubule dynamics and axonal transport in an AD-like context, reducing tau and Aβ levels and promoting neuronal and cognitive protection. These results underline the existence of a crosstalk between cytoskeleton pathology and the two major AD protein lesions. Therefore, microtubule stabilizers could be considered therapeutic agents to slow the progression of both tau and Aβ pathology.

AB0981 VALIDATION OF THE CAREGIVERS QUESTIONNAIRE (IMPACT OF PEDIATRIC RHEUMATIC DISEASES ON CAREGIVERS MULTIASSESSMENT QUESTIONNAIRE) IN PEDIATRIC RHEUMATIC DISEASES

Background:

The CAREGIVERS questionnaire is used as a multidimension screening instrument for burden of caregivers, it allows to examine the impact of juvenile idiopathic arthritis (JIA) on several areas of the caregiver’s life, looking for specific concerns and needs in which treatment could be required. This instrument has shown a good understanding among participants, reliability and consistency to measure the psychosocial and economic impact on primary caregivers of patients with JIA.

Objectives:

The aim of this study is to validate CAREGIVERS questionnaire with the most common pediatric rheumatic diseases, such as JIA, systemic lupus erythematosus (SLE) and juvenile dermatomyositis (JDM).

Methods:

The external validation phase of the constructed questionnaire will be carried out following Feinstein’s clinimetric and psychometrics methodology, to measure the impact of the disease on the caregiver and create a risk profile for treatment detachment.

Results:

A total of 200 questionnaires are applied to caregivers of pediatric patients with rheumatic diseases: 109 caregivers of patients with JIA, 28 caregivers of patients with DMJ and 63 caregivers of patients with SLE. When analyzing all the questions together, a general Cronbach’s alpha of 0.6751 was obtained (Table 1).

Table 1.

External validation of the Questionnaire

DimensionNumero de ÍtemsAlfa de CronbachI. Impacto Emocional60.5669II. Impacto Social30.47IIIA. Impacto Financiero40.6736IIIB. Impacto Laboral30.3151IV. Impacto Familiar50.4948V. Impacto en la Relación entre Cuidador-paciente1NAVI. Impacto en la relación de pareja1NAVII. Impacto en la Religión/Creencias/Espiritualidad1NAVIII. Impacto de las Redes Sociales40.6642Total280.6751

Conclusion:

The CAREGIVERS questionnaire showed to be validated to assess the impact of pediatric rheumatic diseases.

References:

[1]Keppeke, L.d., Molina, J., Miotto e Silva, V.B.et al.Psychological characteristics of caregivers of pediatric patients with chronic rheumatic disease in relation to treatment adherence.Pediatr Rheumatol16,63 (2018).https://doi.org/10.1186/s12969-018-0280-7

[2]Cohen EM, Morley-Fletcher A, Mehta DH, Lee YC. A systematic review of psychosocial therapies for children with rheumatic diseases. Pediatr Rheumatol [Internet]. Pediatric Rheumatology; 2017;15(1):6. Available from:http://ped-rheum.biomedcentral.com/articles/10.1186/s12969-016-0133-1.

[3]Torres-Made, M.D., Peláez-Ballestas, I., García-Rodríguez, F.et al.Development and validation of the CAREGIVERS questionnaire: multi-assessing the impact of juvenile idiopathic arthritis on caregivers.Pediatr Rheumatol18,3 (2020).https://doi.org/10.1186/s12969-020-0400-z

[4]Feinstein AR. Clinimetrics. New Haven: Yale University Press, 1987.

Disclosure of Interests:

None declared

Cytomegalovirus infection in HIV-infected patients in the era of combination antiretroviral therapy

Background

Cytomegalovirus infection dramatically decreased with the introduction of antiretroviral therapy. Whether incidence, clinical characteristics and prognosis of cytomegalovirus in HIV infected patients, has changed over time is. scarcely known.

Methods

Retrospective single-center study. Patients included in this study were all HIV infected patients that went to our center for any disease, and were diagnosed with cytomegalovirus, during the period 2004–2015. epidemiological, clinical and laboratory patients variables were collected in a clinical database. Clinical characteristics, incidence of cytomegalovirus and predictors of mortality during the study were assessed. Results were considered statistically significant when p < 0.05. All statistical analyses were calculated by SPSS version 20.0 (Chicago, IL,USA).

Results

Fifty-six cases of cytomegalovirus infection, in HIV infected patients were identified during the study period (incidence rate-1.7 cases per 1000 persons/year). The most frequent presentation was systemic illness in 43% of cases. Of note,no patients presented with ophthalmic manifestations. The 30-days mortality was 18%. Predictors of mortality were, in the univariate analysis, admission to the intensive care unit OR 32.4 (3.65–287.06) p = 0.0001, and mechanic ventilation 84 OR (8.27–853.12) p = 0.0001, and ART OR 4.1 (0.97–17.31) p = 0.044. These variables were assessed by multivariate analysis, and only mechanical ventilation was statistically significant (p < 0.05)

Conclusion

Incidence of cytomegalovirus infection was higher than described in the antiretroviral therapy era. Clinical presentation has changed. Mechanic ventilation predicted mortality.

P2750Why should cardiopulmonary exercise testing be routinely used for assessing patients with valvular heart disease?

Introduction

The role of cardiopulmonary exercise testing (CPET) is unquestionable to assess prognosis in heart failure. In patients with valvular heart disease (VHD), the functional capacity (FC) is crucial to aid in the right timing of surgery. The aim of this study was to compare the assessment of the FC by CPET and NYHA and the correlation between ventilatory efficiency parameters and resting systolic pulmonary artery pressure (SPAP).

Methods

We studied 100 VHD patients (57% female) who underwent a CPET. We calculated the real METS (RM) as indexed peak VO2/3.5 (1 MET=3.5 ml O2/kg/min) and compared to estimated METS (EM) derived by the time of exercise. An agreement analysis between RM, EM and NYHA was calculated. The correlation among VE/Vslope CO2, EqCO2at anaerobic threshold (AT), PETCO2, partial pressure end-tidal CO2 at AT and SPAP was analyzed.

Results

The results are shown in Table and Figure. The RM and the EM were 4.7±1.7 and 5.5±3, respectively (p<0.01) with a low agreement (ICC=0.6, p<0.01). The agreement between NYHA and the classification obtained from peak % of predicted peak VO2 was very low (weighted kappa =0.06, p=0.28). In patients with severe mitral VHD, the ventilatory efficiency parameters were correlated with SPAP (PETCO2 (AT), r=−0.7, p=0.002; EqCO2 (AT), r=0.5, p=0.04:VE/Vslope CO2, r=0.3, p 0.2), whereas in those with severe aortic VHD, these correlations were much lower (PETCO2 (AT), r=−0.3, p=0.13; EqCO2 (AT), r=0.2, p=0.15; VE/Vslope CO2, r=0.18, p 0.31).

Total (n=100) Mitral regurgitation (n=35) Aortic regurgitation (n=23) Age 65 (29–86) 66 (30–84) 65 (11–87) LVEF (%) 62±6 63±6 61±7 SPAP (mmHg) 40±11 39±11 36±8 NYHA I (60%), II (33%), III (7%) I (63%), II (29%), III (9%) I (63%), II (33%), III (4%) Indexed peak VO2 (ml/min/kg) 16±6 17±6 19±8 Peak % predicted VO2 73±18 74±17 79±18 Predicted VO2 AT (%) 58±19 54±19 61±22 Eq CO2 AT 33±6 32±7 32±5 VE/VSlope CO2 33±6 32±7 33±8 PetCO2 AT 34±4 36±4 36±5

Type and degree of VHD

Conclusions

NYHA scale and estimation of METS derived from the time of exercise clearly overestimated the FC of our population. In our series, the ventilatory inefficiency in patients with mitral VHD could be a surrogate marker of advanced disease and could lead to an earlier intervention.

Distinct Microglial Responses in Two Transgenic Murine Models of TAU Pathology

Microglial cells are crucial players in the pathological process of neurodegenerative diseases, such as Alzheimer’s disease (AD). Microglial response in AD has been principally studied in relation to amyloid-beta pathology but, comparatively, little is known about inflammatory processes associated to tau pathology. In the hippocampus of AD patients, where tau pathology is more prominent than amyloid-beta pathology, a microglial degenerative process has been reported. In this work, we have directly compared the microglial response in two different transgenic tau mouse models: ThyTau22 and P301S. Surprisingly, these two models showed important differences in the microglial profile and tau pathology. Where ThyTau22 hippocampus manifested mild microglial activation, P301S mice exhibited a strong microglial response in parallel with high phospho-tau accumulation. This differential phospho-tau expression could account for the different microglial response in these two tau strains. However, soluble (S1) fractions from ThyTau22 hippocampus presented relatively high content of soluble phospho-tau (AT8-positive) and were highly toxic for microglial cells in vitro, whereas the correspondent S1 fractions from P301S mice displayed low soluble phospho-tau levels and were not toxic for microglial cells. Therefore, not only the expression levels but the aggregation of phospho-tau should differ between both models. In fact, most of tau forms in the P301S mice were aggregated and, in consequence, forming insoluble tau species. We conclude that different factors as tau mutations, accumulation, phosphorylation, and/or aggregation could account for the distinct microglial responses observed in these two tau models. For this reason, deciphering the molecular nature of toxic tau species for microglial cells might be a promising therapeutic approach in order to restore the deficient immunological protection observed in AD hippocampus.

Microglia in Alzheimer's Disease: Activated, Dysfunctional or Degenerative

Microglial activation has been considered a crucial player in the pathological process of multiple human neurodegenerative diseases. In some of these pathologies, such as Amyotrophic Lateral Sclerosis or Multiple Sclerosis, the immune system and microglial cells (as part of the cerebral immunity) play a central role. In other degenerative processes, such as Alzheimer’s disease (AD), the role of microglia is far to be elucidated. In this “mini-review” article, we briefly highlight our recent data comparing the microglial response between amyloidogenic transgenic models, such as APP/PS1 and AD patients. Since the AD pathology could display regional heterogeneity, we focus our work at the hippocampal formation. In APP based models a prominent microglial response is triggered around amyloid-beta (Aβ) plaques. These strongly activated microglial cells could drive the AD pathology and, in consequence, could be implicated in the neurodegenerative process observed in models. On the contrary, the microglial response in human samples is, at least, partial or attenuated. This patent difference could simply reflect the lower and probably slower Aβ production observed in human hippocampal samples, in comparison with models, or could reflect the consequence of a chronic long-standing microglial activation. Beside this differential response, we also observed microglial degeneration in Braak V–VI individuals that, indeed, could compromise their normal role of surveying the brain environment and respond to the damage. This microglial degeneration, particularly relevant at the dentate gyrus, might be mediated by the accumulation of toxic soluble phospho-tau species. The consequences of this probably deficient immunological protection, observed in AD patients, are unknown.

IgE responses to Ascaris and mite tropomyosins are risk factors for asthma

BACKGROUND

The relationship between helminthiases and allergy is a matter of considerable interest and research. In the tropics, house dust mite exposure, a known risk factor for asthma, is frequently concurrent with helminth infections. It remains to be defined whether infection with the common roundworm Ascaris or its bystander immunological effects influence the prevalence and pathogenesis of asthma independently of mite sensitization.

OBJECTIVE

To investigate the relationship between the IgE responses to Ascaris and its purified allergens and the risk of asthma in a tropical country.

METHODS

A nested case-control study was performed in 356 subjects who reported current and past asthma symptoms (asthmatics) and 435 controls that had never experienced such symptoms. They were tested for serum levels of total IgE and specific IgE to Ascaris extract, Asc s 1 (ABA-1), Asc l 3 (tropomyosin) and GST (glutathione transferase). In addition, specific IgE to Dermatophagoides pteronyssinus, Blomia tropicalis and their tropomyosins Der p 10 and Blo t 10 was measured. Sensitization was defined as a positive specific IgE result to any extract or recombinant allergen.

RESULTS

Sensitization to Ascaris and D. pteronyssinus was independently associated with asthma after adjustment for age, gender, socio-economic stratum, city and other IgE levels (adjusted ORs: 2.17; 95% CI 1.37-3.42 and 2.46; 95% CI 1.54-3.92), respectively. There was also a significant association with sensitization to the highly allergenic and cross-reactive tropomyosins Asc l 3, Blo t 10 and Der p10 (aORs: 1.76; 95% CI 1.21-2.57, 1.64; 95% CI 1.14-2.35 and 1.51; 95% CI 1.02-2.24), respectively.

CONCLUSION AND CLINICAL RELEVANCE

IgE responses to Ascaris are associated with asthma symptoms in a population living in the tropics. Sensitization to the cross-reactive Ascaris and mite tropomyosins partially underlies this finding. These results have potential relevance in asthma diagnosis and management.

Amyloid-β reduces the expression of neuronal FAIM-L, thereby shifting the inflammatory response mediated by TNFα from neuronal protection to death

The brains of patients with Alzheimer's disease (AD) present elevated levels of tumor necrosis factor-α (TNFα), a cytokine that has a dual function in neuronal cells. On one hand, TNFα can activate neuronal apoptosis, and on the other hand, it can protect these cells against amyloid-β (Aβ) toxicity. Given the dual behavior of this molecule, there is some controversy regarding its contribution to the pathogenesis of AD. Here we examined the relevance of the long form of Fas apoptotic inhibitory molecule (FAIM) protein, FAIM-L, in regulating the dual function of TNFα. We detected that FAIM-L was reduced in the hippocampi of patients with AD. We also observed that the entorhinal and hippocampal cortex of a mouse model of AD (PS1_M146LxAPP_751sl) showed a reduction in this protein before the onset of neurodegeneration. Notably, cultured neurons treated with the cortical soluble fractions of these animals showed a decrease in endogenous FAIM-L, an effect that is mimicked by the treatment with Aβ-derived diffusible ligands (ADDLs). The reduction in the expression of FAIM-L is associated with the progression of the neurodegeneration by changing the inflammatory response mediated by TNFα in neurons. In this sense, we also demonstrate that the protection afforded by TNFα against Aβ toxicity ceases when endogenous FAIM-L is reduced by short hairpin RNA (shRNA) or by treatment with ADDLs. All together, these results support the notion that levels of FAIM-L contribute to determine the protective or deleterious effect of TNFα in neuronal cells.

Disruption of amyloid plaques integrity affects the soluble oligomers content from Alzheimer disease brains

The implication of soluble Abeta in the Alzheimer’s disease (AD) pathology is currently accepted. In fact, the content of soluble extracellular Abeta species, such as monomeric and/or oligomeric Abeta, seems to correlate with the clinico-pathological dysfunction observed in AD patients. However, the nature (monomeric, dimeric or other oligomers), the relative abundance, and the origin (extra-/intraneuronal or plaque-associated), of these soluble species are actually under debate. In this work we have characterized the soluble (defined as soluble in Tris-buffered saline after ultracentrifugation) Abeta, obtained from hippocampal samples of Braak II, Braak III–IV and Braak V–VI patients. Although the content of both Abeta40 and Abeta42 peptides displayed significant increase with pathology progression, our results demonstrated the presence of low, pg/µg protein, amount of both peptides. This low content could explain the absence (or below detection limits) of soluble Abeta peptides detected by western blots or by immunoprecipitation-western blot analysis. These data were in clear contrast to those published recently by different groups. Aiming to explain the reasons that determine these substantial differences, we also investigated whether the initial homogenization could mobilize Abeta from plaques, using 12-month-old PS1xAPP cortical samples. Our data demonstrated that manual homogenization (using Dounce) preserved the integrity of Abeta plaques whereas strong homogenization procedures (such as sonication) produced a vast redistribution of the Abeta species in all soluble and insoluble fractions. This artifact could explain the dissimilar and somehow controversial data between different groups analyzing human AD samples.

In vivo modification of Abeta plaque toxicity as a novel neuroprotective lithium-mediated therapy for Alzheimer's disease pathology

Background

Alzheimer’s disease (AD) is characterized by the abnormal accumulation of extracellular beta-amyloid (Abeta) plaques, intracellular hyperphosphorylated tau, progressive synaptic alterations, axonal dystrophies, neuronal loss and the deterioration of cognitive capabilities of patients. However, no effective disease-modifying treatment has been yet developed. In this work we have evaluated whether chronic lithium treatment could ameliorate the neuropathology evolution of our well characterized PS1M146LxAPPSwe-London mice model.

Results

Though beneficial effects of lithium have been previously described in different AD models, here we report a novel in vivo action of this compound that efficiently ameliorated AD-like pathology progression and rescued memory impairments by reducing the toxicity of Abeta plaques. Transgenic PS1M146LxAPPSwe-London mice, treated before the pathology onset, developed smaller plaques characterized by higher Abeta compaction, reduced oligomeric-positive halo and therefore with attenuated capacity to induce neuronal damage. Importantly, neuronal loss in hippocampus and entorhinal cortex was fully prevented. Our data also demonstrated that the axonal dystrophic area associated with lithium-modified plaques was highly reduced. Moreover, a significant lower accumulation of phospho-tau, LC3-II and ubiquitinated proteins was detected in treated mice. Our study highlights that this switch of plaque quality by lithium could be mediated by astrocyte activation and the release of heat shock proteins, which concentrate in the core of the plaques.

Conclusions

Our data demonstrate that the pharmacological in vivo modulation of the extracellular Abeta plaque compaction/toxicity is indeed possible and, in addition, might constitute a novel promising and innovative approach to develop a disease-modifying therapeutic intervention against AD.