Why am I overwhelmed by bright lights? The behavioural mechanisms of post-stroke visual hypersensitivity

After stroke, patients can experience visual hypersensitivity, an increase in their sensitivity for visual stimuli as compared to their state prior to the stroke. Candidate behavioural mechanisms for these subjective symptoms are atypical bottom-up sensory processing and impaired selective attention, but empirical evidence is currently lacking. In the current study, we aimed to investigate the relationship between post-stroke visual hypersensitivity and sensory thresholds, sensory processing speed, and selective attention using computational modelling of behavioural data. During a whole/partial report task, participants (51 stroke patients, 76 orthopedic patients, and 77 neurotypical adults) had to correctly identify a single target letter that was presented alone (for 17-100 ms) or along a distractor (for 83ms). Performance on this task was used to estimate the sensory threshold, sensory processing speed, and selective attention abilities of each participant. In the stroke population, both on a group and individual level, there was evidence for impaired selective attention and -to a lesser extent- lower sensory thresholds in patients with post-stroke visual hypersensitivity as compared to neurotypical adults, orthopedic patients, or stroke patients without post-stroke sensory hypersensitivity. These results provide a significant advancement in our comprehension of post-stroke visual hypersensitivity and can serve as a catalyst for further investigations into the underlying mechanisms of sensory hypersensitivity after other types of acquired brain injury as well as post-injury hypersensitivity for other sensory modalities.

The global distribution of plants used by humans

Plants sustain human life. Understanding geographic patterns of the diversity of species used by people is thus essential for the sustainable management of plant resources. Here, we investigate the global distribution of 35,687 utilized plant species spanning 10 use categories (e.g., food, medicine, material). Our findings indicate general concordance between utilized and total plant diversity, supporting the potential for simultaneously conserving species diversity and its contributions to people. Although Indigenous lands across Mesoamerica, the Horn of Africa, and Southern Asia harbor a disproportionate diversity of utilized plants, the incidence of protected areas is negatively correlated with utilized species richness. Finding mechanisms to preserve areas containing concentrations of utilized plants and traditional knowledge must become a priority for the implementation of the Kunming-Montreal Global Biodiversity Framework.

Promoting physical activity and a healthy active lifestyle in community-dwelling older adults: a design thinking approach for the development of a mobile health application

Background

Physical activity (PA) has wide-ranging, and well documented benefits for older adults, encompassing physical, cognitive, and mental well-being. The World Health Organization advocates for a minimum of 150-300 min of moderate intensity PA per week, supplemented by muscle-strengthening exercises. However, the rates of PA among older adults remain a concern. While portable technologies hold promises in promoting PA, sustaining long-term engagement continues to be a challenge.

Objective

The aims of this study are to identify barriers and facilitators to PA in older adults, to develop an mHealth app promoting PA and an active healthy lifestyle in collaboration with community-dwelling older adults guided by the design thinking process, and to test it.

Methods

A co-creative process was used, employing design thinking. Interviews were conducted to understand the needs of the target population and identify the problem of insufficient PA. Two cocreation sessions involving older adults and experts were conducted to generate innovative ideas. Participants were selected based on age (≥65 years), no severe illness, Dutch language proficiency, and active participation ability. Results were qualitatively analyzed and coded. Finally a prototype was developed and tested.

Results

Interviews with older adults highlighted diverse perceptions of PA but unanimous agreement on its importance. They recognized health benefits such as improved mobility, balance, and reduced fall risk, while emphasizing the social and mental aspects. Barriers included poor health, time constraints, weather conditions and fear of falling. Cocreation sessions identified key topics: perception of a healthy lifestyle, coping strategies, mHealth App features, screen visualization, and tailored notifications, which led to the development of a mobile app promoting PA and an active lifestyle. The app was stepwise prototyped.

Conclusion

This study emphasizes the importance of promoting PA among older adults through a collaborative design thinking approach. However, the implementation of mHealth apps faces obstacles due to the digital divide, necessitating personalized solutions to bridge the gap. Moreover, it calls for further research to investigate the long-term impact of such interventions and explore behavior change patterns in this population.

Smart Nursing: The Use of Technology to Support Homecare Nurses with Their Care of the Elderly

The demand for homecare services is on the rise, while simultaneously there is a shortage of homecare nurses who are burdened with increasingly heavier workloads. The introduction of assistive technologies has the potential to assist elderly individuals as well as (informal) caregivers. This study aims to facilitate nursing care with technology, within the framework of a proper daily structure for elderly people. Initially, a needs assessment was performed with homecare nurses to identify the most relevant daily structure patterns. Subsequently, a prototype comprising of a test setup and a mobile application was developed, followed by a case study involving participation from homecare nurses, informal caregivers, and patients. Both subjective experiences and standardized outcome measures (System Usability Scale, Usefulness Satisfaction and Ease of Use Scale and User Experience Questionnaire) revealed highly positive attitudes towards the test setup and application. Future research endeavours should focus on scaling up the technology and expanding its availability to other caregivers.

Performance of Automated ASPECTS Software and Value as a Computer-Aided Detection Tool

BACKGROUND AND PURPOSE

ASPECTS quantifies early ischemic changes in anterior circulation stroke on NCCT but has interrater variability. We examined the agreement of conventional and automated ASPECTS and studied the value of computer-aided detection.

MATERIALS AND METHODS

We retrospectively collected imaging data from consecutive patients with acute ischemic stroke with large-vessel occlusion undergoing thrombectomy. Five raters scored conventional ASPECTS on baseline NCCTs, which were also processed by RAPID software. Conventional and automated ASPECTS were compared with a consensus criterion standard. We determined the agreement over the full ASPECTS range as well as dichotomized, reflecting thrombectomy eligibility according to the guidelines (ASPECTS 0-5 versus 6-10). Raters subsequently scored ASPECTS on the same NCCTs with assistance of the automated ASPECTS outputs, and agreement was obtained.

RESULTS

For the total of 175 cases, agreement among raters individually and the criterion standard varied from fair to good (weighted κ = between 0.38 and 0.76) and was moderate (weighted κ = 0.59) for the automated ASPECTS. The agreement of all raters individually versus the criterion standard improved with software assistance, as did the interrater agreement (overall Fleiss κ = 0.15-0.23; P < .001 and .39 to .55; P = .01 for the dichotomized ASPECTS).

CONCLUSIONS

Automated ASPECTS had agreement with the criterion standard similar to that of conventional ASPECTS. However, including automated ASPECTS during the evaluation of NCCT in acute stroke improved the agreement with the criterion standard and improved interrater agreement, which could, therefore, result in more uniform scoring in clinical practice.

Migraine-Associated Common Genetic Variants Confer Greater Risk of Posterior vs. Anterior Circulation Ischemic Stroke☆

OBJECTIVE

To examine potential genetic relationships between migraine and the two distinct phenotypes posterior circulation ischemic stroke (PCiS) and anterior circulation ischemic stroke (ACiS), we generated migraine polygenic risk scores (PRSs) and compared these between PCiS and ACiS, and separately vs. non-stroke control subjects.

METHODS

Acute ischemic stroke cases were classified as PCiS or ACiS based on lesion location on diffusion-weighted MRI. Exclusion criteria were lesions in both vascular territories or uncertain territory; supratentorial PCiS with ipsilateral fetal posterior cerebral artery; and cases with atrial fibrillation. We generated migraine PRS for three migraine phenotypes (any migraine; migraine without aura; migraine with aura) using publicly available GWAS data and compared mean PRSs separately for PCiS and ACiS vs. non-stroke control subjects, and between each stroke phenotype.

RESULTS

Our primary analyses included 464 PCiS and 1079 ACiS patients with genetic European ancestry. Compared to non-stroke control subjects (n=15396), PRSs of any migraine were associated with increased risk of PCiS (p=0.01-0.03) and decreased risk of ACiS (p=0.010-0.039). Migraine without aura PRSs were significantly associated with PCiS (p=0.008-0.028), but not with ACiS. When comparing PCiS vs. ACiS directly, migraine PRSs were higher in PCiS vs. ACiS for any migraine (p=0.001-0.010) and migraine without aura (p=0.032-0.048). Migraine with aura PRS did not show a differential association in our analyses.

CONCLUSIONS

Our results suggest a stronger genetic overlap between unspecified migraine and migraine without aura with PCiS compared to ACiS. Possible shared mechanisms include dysregulation of cerebral vessel endothelial function.

The effect of fluid bolus administration on cerebral tissue oxygenation in post-cardiac arrest patients

PURPOSE

Fluid boluses (FB) are often used in post-cardiac arrest (CA) patients with haemodynamic instability. Although FB may improve cardiac output (CO) and mean arterial pressure (MAP), FB may also increase central venous pressure (CVP), reduce arterial PaO₂, dilute haemoglobin and cause interstitial oedema. The aim of the present study was to investigate the net effect of FB administration on cerebral tissue oxygenation saturation (SctO₂) in post-CA patients.

METHODS

Pre-planned sub-study of the Neuroprotect post-CA trial (NCT02541591). Patients with anticipated fluid responsiveness based on stroke volume variation (SVV) or passive leg raising test were administered a FB of 500 ml plasma-lyte A (Baxter Healthcare) and underwent pre- and post-FB assessments of stroke volume, CO, MAP, CVP, haemoglobin, PaO₂ and SctO₂.

RESULTS

52 patients (mean age 64 ± 12 years, 75% male) received a total of 115 FB. Although administration of a FB resulted in a significant increase of stroke volume (63 ± 22 vs 67 ± 23 mL, p = 0.001), CO (4,2 ± 1,6 vs 4,4 ± 1,7 L/min, p = 0.001) and MAP (74,8 ± 13,2 vs 79,2 ± 12,9 mmHg, p = 0.004), it did not improve SctO₂ (68.54 ± 6.99 vs 68.70 ± 6.80%, p = 0.49). Fluid bolus administration also resulted in a significant increase of CVP (10,0 ± 4,5 vs 10,7 ± 4,9 mmHg, p = 0.02), but did not affect PaO₂ (99 ± 31 vs 94 ± 31 mmHg, p = 0.15) or haemoglobin concentrations (12,9 ± 2,1 vs 12,8 ± 2,2 g/dL, p = 0.10). In a multivariate model, FB-induced changes in CO (beta 0,77; p = 0.004) and in CVP (beta -0,23; p = 0.02) but not in MAP (beta 0,02; p = 0.18) predicted post-FB ΔSctO₂.

CONCLUSIONS

Despite improvements in CO and MAP, FB administration did not improve SctO₂ in post-cardiac arrest patients.

Polypharmacy, functional outcome and treatment effect of intravenous alteplase for acute ischaemic stroke

BACKGROUND AND PURPOSE

Polypharmacy is an important challenge in clinical practice. Our aim was to determine the effect of polypharmacy on functional outcome and treatment effect of alteplase in acute ischaemic stroke.

METHODS

This was a post hoc analysis of the randomized, placebo-controlled WAKE-UP trial of magnetic resonance imaging guided intravenous alteplase in unknown onset stroke. Polypharmacy was defined as an intake of five or more medications at baseline. Comorbidities were assessed by the Charlson Comorbidity Index (CCI). The primary efficacy variable was favourable outcome defined by a score of 0-1 on the modified Rankin Scale at 90 days. Logistic regression analysis was used to test for an association of polypharmacy with functional outcome, and for interaction of polypharmacy and the effect of thrombolysis.

RESULTS

Polypharmacy was present in 133/503 (26%) patients. Patients with polypharmacy were older (mean age 70 vs. 64 years; p < 0.0001) and had a higher score on the National Institutes of Health Stroke Scale at baseline (median 7 vs. 5; p = 0.0007). A comorbidity load defined by a CCI score ≥ 2 was more frequent in patients with polypharmacy (48% vs. 8%; p < 0.001). Polypharmacy was associated with lower odds of favourable outcome (adjusted odds ratio 0.50, 95% confidence interval 0.30-0.85; p = 0.0099), whilst the CCI score was not. Treatment with alteplase was associated with higher odds of favourable outcome in both groups, with no heterogeneity of treatment effect (test for interaction of treatment and polypharmacy, p = 0.29).

CONCLUSION

In stroke patients, polypharmacy is associated with worse functional outcome after intravenous thrombolysis independent of comorbidities. However, polypharmacy does not interact with the beneficial effect of alteplase.

Correction to: Features of intracranial hemorrhage in cerebral venous thrombosis

The original version of this article unfortunately contained mistakes. The correct information is given below.

Colchicine for stroke prevention in patients with coronary artery disease: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Although clinical trials suggest that colchicine may reduce the risk of vascular events in patients with a history of coronary artery disease, its effect on the prevention of cerebrovascular events still remains unclear.

METHODS

A systematic review and meta-analysis was performed of all available randomized controlled trials (RCTs) reporting on incident strokes during the follow-up of patients with a history of cardiovascular disease randomized to colchicine treatment or control (placebo or usual care).

RESULTS

Four RCTs were identified, including a total of 5553 patients (mean age 61 years, 81% males), with a follow-up ranging from 1 to 36 months. Colchicine treatment was associated with a significantly lower risk of incident stroke during follow-up compared to control (risk ratio 0.31, 95% confidence interval 0.13-0.71), without heterogeneity across included studies (I²  = 0%). Based on the pooled incident stroke rate of control groups (0.9%) in the included RCTs, it was estimated that administration of low-dose colchicine to 161 patients with coronary artery disease would prevent one stroke during a follow-up of 23 months.

CONCLUSION

Colchicine treatment decreases stroke risk in patients with a history of coronary artery disease. The effect of colchicine in secondary stroke prevention is currently being evaluated in an ongoing RCT.

Detailed phenotyping of posterior vs. anterior circulation ischemic stroke: a multi-center MRI study

OBJECTIVE

Posterior circulation ischemic stroke (PCiS) constitutes 20-30% of ischemic stroke cases. Detailed information about differences between PCiS and anterior circulation ischemic stroke (ACiS) remains scarce. Such information might guide clinical decision making and prevention strategies. We studied risk factors and ischemic stroke subtypes in PCiS vs. ACiS and lesion location on magnetic resonance imaging (MRI) in PCiS.

METHODS

Out of 3,301 MRIs from 12 sites in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Genetics Network (SiGN), we included 2,381 cases with acute DWI lesions. The definition of ACiS or PCiS was based on lesion location. We compared the groups using Chi-squared and logistic regression.

RESULTS

PCiS occurred in 718 (30%) patients and ACiS in 1663 (70%). Diabetes and male sex were more common in PCiS vs. ACiS (diabetes 27% vs. 23%, p < 0.05; male sex 68% vs. 58%, p < 0.001). Both were independently associated with PCiS (diabetes, OR = 1.29; 95% CI 1.04-1.61; male sex, OR = 1.46; 95% CI 1.21-1.78). ACiS more commonly had large artery atherosclerosis (25% vs. 20%, p < 0.01) and cardioembolic mechanisms (17% vs. 11%, p < 0.001) compared to PCiS. Small artery occlusion was more common in PCiS vs. ACiS (20% vs. 14%, p < 0.001). Small artery occlusion accounted for 47% of solitary brainstem infarctions.

CONCLUSION

Ischemic stroke subtypes differ between the two phenotypes. Diabetes and male sex have a stronger association with PCiS than ACiS. Definitive MRI-based PCiS diagnosis aids etiological investigation and contributes additional insights into specific risk factors and mechanisms of injury in PCiS.

P5715Trends in indications and outcome in thrombolytic therapy: a retrospective single center study

Background

Thrombolytic therapy is used as a lifesaving treatment for a broad range of acute thrombotic events. The role of thrombolysis for its various indications has rapidly evolved.

Purpose

To provide a contemporary overview of current indications and outcome of thrombolytic therapy in clinical practice.

Methods

This retrospective single-center study analyzed indications, complications and short-term mortality of systemic thrombolytic therapy between 2010 and 2016 in a university hospital, totaling 763 cases. Major bleedings were defined using criteria published by the International Society on Thrombosis and Haemostasis (ISTH).

Results

Thrombolytic drugs were mostly used for ischemic strokes (66.6%) and peripheral arterial disease (16.9%). Acute coronary syndrome only represented a minority of cases (in this PCI-center). Overall seven- and thirty-day-mortality were 7.3% and 12.0%, respectively. Major bleeding occurred in 8.3% of patients and was fatal in 0.9% of all patients. Both major bleeding and mortality differed by the indication for thrombolysis. Thrombolytic therapy for pulmonary embolism and peripheral arterial disease were associated with the highest rates of major bleeding, 28.6% and 23.3% respectively. Short-term mortality was highest in patients receiving thrombolysis for pulmonary embolism. Predictors for major bleeding included use of antiplatelet and anticoagulation drugs prior to thrombolysis. Major bleedings, age and concomitant anticoagulation were associated with lower survival rates.

Indications in absolute numbers – 2010 – – 2011 – – 2012 – – 2013 – – 2014 – – 2015 – – 2016 – Ischemic Stroke 56 63 66 57 96 88 82 Peripheral Arterial Disease 21 23 21 28 14 16 6 Pulmonary Embolism 4 9 10 10 5 8 8 Deep Vein Thrombosis 2 1 2 0 2 3 3 Acute Coronary Syndrome 0 1 0 1 0 0 0 Mechanical Heart Valve Thrombosis 1 3 3 1 2 7 1 Other 5 8 3 10 2 5 6 TOTAL 89 108 105 107 121 127 106

Mortality and major bleeding in %

Conclusion

The use of thrombolytic therapy has evolved, with stroke now being the most frequent indication. Mortality and bleeding rates are significant and vary considerably per indication. Major bleedings, age and maintenance anticoagulant therapy were risk factors associated with lower survival rates, but the underlying disease and patient population seem to play a major role in survival as well.

The relationship between motor abilities and quality of life in children with severe multiple disabilities

BACKGROUND

This study aimed to determine the relationship between motor abilities and quality of life in children with severe multiple disabilities.

METHODS

In this cross-sectional study, motor abilities of 29 children (mean age 9.8 years; 45% girls) with severe multiple disabilities [IQ < 25; Gross Motor Function Motor Classification System level V] were measured with the MOtor eVAluation in Kids with Intellectual and Complex disabilities (Movakic) questionnaire (completed by the child's physical therapist). Quality of life was measured with the Quality of Life-Profound Multiple Disabilities (QoL-PMD) questionnaire (completed by the child's parents).

RESULTS

A significantly moderate to high correlation was found between the total scores on the Movakic and the QoL-PMD (r = 0.40, P = 0.03), indicating that higher scores in motor abilities are associated with a higher level of quality of life. Furthermore, significantly moderate to high correlations were found between the total score on the Movakic and the dimension Physical Well-Being, Development and Activities of the Qol-PMD. In multiple linear regression models, all significant bivariate relationships between the Movakic total scores and QoL-PMD dimensions remained significant after controlling for the Gross Motor Function Motor Classification System level.

CONCLUSIONS

In these children with severe multiple disabilities, motor abilities (as measured by Movakic) are moderately related to quality of life (as measured by the QoL-PMD).

Obstacle: A Tool to Assess the Home Environment Designed for All

INTRODUCTION

Elderly prefer to live as long as possible independent in their own home. The occupational therapist can play an important role in this, for instance by giving advice regarding home adaptations or the use of assistive technology in order for the person to function more independently. There is need for a tool that allow to screen the home easily and thorough.

AIM

The aim of the study is to develop a screening tool that meets the requirements of occupational therapists to assess the home environment for persons in order to facilitate independent living.

METHODS

The screening tool 'Obstacle' was developed and tested in 3 phases within an iterative way using a user-centred design. Firstly, crucial items based on literature and expertise of researchers and occupational therapists in the field were identified and the Obstacle paper version and manual was developed. Secondly, the tool was adapted and digitalised to be used on a tablet. Thirdly, a mini-version of Obstacle was created, being less time consuming and usable as a signalling tool to determine the need for applying the extensive version. The tool was tested by screening homes of 96 elderly in total. Additionally, opinions of 5 elderly, 5 informal caregivers and 5 professional caregivers were gathered with a focus group.

RESULTS

The digital screening tool Obstacle is developed and includes 13 rooms to be screened with specific items for each room to be scored. Obstacle was judged very useful by occupational therapists.

CONCLUSION

The novelty of this tool is the focus on independent living and the starting point of occupational performance, reduce the risk of falling and facilitating in advising the optimal home adaptations.

Possible familial presentation in two siblings with carotid fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease which can affect the cervical, renal and visceral arteries. Here we report on two sisters diagnosed with carotid FMD at the same age, presenting with similar symptoms of pulsating tinnitus. The familial presentation of this rare disorder attracted our attention and was suggestive of a genetic etiology. Conservative treatment with aspirin was initiated. Carotid FMD is a rare disorder of which the exact pathophysiology is not known. A review of the literature on the clinical presentation, diagnosis and management is presented. In addition possible etiological factors and the genetic nature of the disease are discussed.

Possible Familial Presentation in Two Siblings with Carotid Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease which can affect the cervical, renal and visceral arteries. Here we report on two sisters diagnosed with carotid FMD at the same age, presenting with similar symptoms of pulsating tinnitus. The familial presentation of this rare disorder attracted our attention and was suggestive of a genetic etiology. Conservative treatment with aspirin was initiated. Carotid FMD is a rare disorder of which the exact pathophysiology is not known. A review of the literature on the clinical presentation, diagnosis and management is presented. In addition possible etiological factors and the genetic nature of the disease are discussed.

Etiology of first-ever ischaemic stroke in European young adults: the 15 cities young stroke study

BACKGROUND AND PURPOSE

Risk factors for IS in young adults differ between genders and evolve with age, but data on the age- and gender-specific differences by stroke etiology are scare. These features were compared based on individual patient data from 15 European stroke centers.

METHODS

Stroke etiology was reported in detail for 3331 patients aged 15-49 years with first-ever IS according to Trial of Org in Acute Stroke Treatment (TOAST) criteria: large-artery atherosclerosis (LAA), cardioembolism (CE), small-vessel occlusion (SVO), other determined etiology, or undetermined etiology. CE was categorized into low- and high-risk sources. Other determined group was divided into dissection and other non-dissection causes. Comparisons were done using logistic regression, adjusting for age, gender, and center heterogeneity.

RESULTS

Etiology remained undetermined in 39.6%. Other determined etiology was found in 21.6%, CE in 17.3%, SVO in 12.2%, and LAA in 9.3%. Other determined etiology was more common in females and younger patients, with cervical artery dissection being the single most common etiology (12.8%). CE was more common in younger patients. Within CE, the most frequent high-risk sources were atrial fibrillation/flutter (15.1%) and cardiomyopathy (11.5%). LAA, high-risk sources of CE, and SVO were more common in males. LAA and SVO showed an increasing frequency with age. No significant etiologic distribution differences were found amongst southern, central, or northern Europe.

CONCLUSIONS

The etiology of IS in young adults has clear gender-specific patterns that change with age. A notable portion of these patients remains without an evident stroke mechanism according to TOAST criteria.

Acute Cerebrovascular Disease in the Young

Background and Purpose—

Strokes have especially devastating implications if they occur early in life; however, only limited information exists on the characteristics of acute cerebrovascular disease in young adults. Although risk factors and manifestation of atherosclerosis are commonly associated with stroke in the elderly, recent data suggests different causes for stroke in the young. We initiated the prospective, multinational European study Stroke in Young Fabry Patients (sifap) to characterize a cohort of young stroke patients.

Methods—

Overall, 5023 patients aged 18 to 55 years with the diagnosis of ischemic stroke (3396), hemorrhagic stroke (271), transient ischemic attack (1071) were enrolled in 15 European countries and 47 centers between April 2007 and January 2010 undergoing a detailed, standardized, clinical, laboratory, and radiological protocol.

Results—

Median age in the overall cohort was 46 years. Definite Fabry disease was diagnosed in 0.5% (95% confidence interval, 0.4%–0.8%; n=27) of all patients; and probable Fabry disease in additional 18 patients. Males dominated the study population (2962/59%) whereas females outnumbered men (65.3%) among the youngest patients (18–24 years). About 80.5% of the patients had a first stroke. Silent infarcts on magnetic resonance imaging were seen in 20% of patients with a first-ever stroke, and in 11.4% of patients with transient ischemic attack and no history of a previous cerebrovascular event. The most common causes of ischemic stroke were large artery atherosclerosis (18.6%) and dissection (9.9%).

Conclusions—

Definite Fabry disease occurs in 0.5% and probable Fabry disease in further 0.4% of young stroke patients. Silent infarcts, white matter intensities, and classical risk factors were highly prevalent, emphasizing the need for new early preventive strategies.

Clinical Trial Registration Information—

URL: http://www.clinicaltrials.gov .Unique identifier: NCT00414583

Tau levels do not influence human ALS or motor neuron degeneration in the SOD1G93A mouse

BACKGROUND

The microtubule-associated protein tau is thought to play a pivotal role in neurodegeneration. Mutations in the tau coding gene MAPT are a cause of frontotemporal dementia, and the H1/H1 genotype of MAPT, giving rise to higher tau expression levels, is associated with progressive supranuclear palsy, corticobasal degeneration, and Parkinson disease (PD). Furthermore, tau hyperphosphorylation and aggregation is a hallmark of Alzheimer disease (AD), and reducing endogenous tau has been reported to ameliorate cognitive impairment in a mouse model for AD. Tau hyperphosphorylation and aggregation have also been described in amyotrophic lateral sclerosis (ALS), both in human patients and in the mutant SOD1 mouse model for this disease. However, the precise role of tau in motor neuron degeneration remains uncertain.

METHODS

The possible association between ALS and the MAPT H1/H2 polymorphism was studied in 3,540 patients with ALS and 8,753 controls. Furthermore, the role of tau in the SOD1(G93A) mouse model for ALS was studied by deleting Mapt in this model.

RESULTS

The MAPT genotype of the H1/H2 polymorphism did not influence ALS susceptibility (odds ratio = 1.08 [95% confidence interval 0.99-1.18], p = 0.08) and did not affect the clinical phenotype. Lowering tau levels in the SOD1(G93A) mouse failed to delay disease onset (p = 0.302) or to increase survival (p = 0.557).

CONCLUSION

These findings suggest that the H1/H2 polymorphism in MAPT is not associated with human amyotrophic lateral sclerosis, and that lowering tau levels in the mutant SOD1 mouse does not affect the motor neuron degeneration in these animals.

Role of heat shock response and Hsp27 in mutant SOD1-dependent cell death

The fatal neurodegenerative disorder amyotrophic lateral sclerosis (ALS) is characterized by selective loss of motor neurons and mutations in the copper-zinc superoxide dismutase (SOD1) enzyme underlie one form of familial ALS. The pathogenic mechanism of these mutations is elusive but is thought to involve oxidative stress and protein aggregation. These two phenomena are known to induce heat shock proteins (Hsps) which protect stressed cells through their chaperoning and anti-apoptotic activity. In order to investigate the role of Hsp27 in mutant SOD1-dependent cell death, we used mutant and wild type SOD1 overexpressing N2a mouse neuroblastoma cells. Mutant SOD1-dependent cell death could be induced by heat shock, and by treating the cells with cyclosporine A or lactacystin. Transfection with an Hsp27 expression construct did not protect the N2a cells against mutant SOD1-dependent cell death. However, pre-conditioning N2a cells with a mild heat shock was accompanied by a significant upregulation of Hsp27 in the mutant SOD1 cells, and protected these cells against subsequent cell death induced by a more severe heat shock. Selective inhibition of the Hsp27 upregulation, through the use of Hsp27 siRNA, did not attenuate the protective effect of this treatment. These results show that activation of the heat shock response protects cells against mutant SOD1-dependent cell death, but that Hsp27 is not an essential component of the stress response leading to protection.

The direct and indirect costs of the chronic management of osteoporosis: a prospective follow-up of 3440 active subjects

INTRODUCTION

The objective of this study was to estimate the direct and indirect costs attributable to osteoporosis (OP) from a societal and a payer's perspective among active subjects living in Belgium and employed in the public workforce.

MATERIALS AND METHODS

A cohort of 3440 subjects employed by the Liege City Council was followed for 6 months. The City Council employees were invited to fill a monthly log of the data related to their utilization of health resources (contacts with health professionals, medical examinations, drug use,...) due to OP. Information on work disability (number of days of sick leave) and on informal care (number of days off work incurred by active subjects in helping relatives or friends suffering from OP) was also collected.

RESULTS

Of those asked to participate in the study, 1,811 subjects filled in at least one questionnaire. The mean duration of follow-up was 3.46 months. Self-reported prevalence of OP at inclusion was 5.3%. OP subjects were significantly older (52.7+/-6.1 years) than normal subjects (45.5+/-9.8 years) (p<0.05) and included more women (85.3 vs. 55.9%). Direct costs came to 44.6 euros per OP patient-month: 10.9 euros was spent on contact with health professionals, 19.0 euros on medical examinations, 12.1 euros on drugs and 2.6 euros on hospitalizations. During this 6-month study, a total of 140 days of sick leave was recorded (mean: 0.4 per OP patient-month). From a payer's perspective, this loss in productivity yielded a mean cost of 34.05 euros per OP patient-month. A mean number of days off work of 0.018 per active subject-month, attributable to informal care, was recorded. These days of inactivity represented, for the employer, a mean cost of 1.8 euros per active subject-month.

CONCLUSION

The results of this survey of a large sample of active subjects confirm that OP-related expenditures, both for medical care and for loss of productivity, are significant.

Cultured astrocytes react to LPS with increased cyclooxygenase activity and phagocytosis

Phagocytosis and prostaglandin E(2) production were investigated in purified cultures of perinatal rat forebrain astrocytes. Light and electron microscopic data indicated that astrocytes respond to bacterial endotoxin, lipopolysaccharide (LPS) by increased phagocytosis and by activating the cyclooxygenase enzyme-pathway. LPS-inducible phagocytosis of astrocytes was demonstrated by electron microscopic studies on colloidal gold uptake and by photometric determination of fluorescent bead ingestion. The internalisation of fragments of the plasma membrane was shown by histochemical detection of membrane-bound ecto-ATPase activity within intracellular vesicles. Activation of the cyclooxygenase pathway, a characteristic reaction of immune cells under inflammatory conditions, was also detected in astroglial cells upon treatment with LPS. The increased prostaglandin E(2) (PGE(2)) production by astrocytes in response to LPS was reduced by the non-steroid anti-inflammatory drug, indomethacin. Our data indicate that astrocytes display some tissue-protective reactions in response to inflammation inducing factors, even in the absence of peripheral immune cells or central microglia. The role of inducible astrocytic phagocytosis in a non-immune protection-pathway is discussed.

Ca2+-induced Ca2+ release from the endoplasmic reticulum amplifies the Ca2+ signal mediated by activation of voltage-gated L-type Ca2+ channels in pancreatic beta-cells

Stimulus-secretion coupling in pancreatic beta-cells involves membrane depolarization and Ca(2+) entry through voltage-gated L-type Ca(2+) channels, which is one determinant of increases in the cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)). We investigated how the endoplasmic reticulum (ER)-associated Ca(2+) apparatus further modifies this Ca(2+) signal. When fura-2-loaded mouse beta-cells were depolarized by KCl in the presence of 3 mm glucose, [Ca(2+)](i) increased to a peak in two phases. The second phase of the [Ca(2+)](i) increase was abolished when ER Ca(2+) stores were depleted by thapsigargin. The steady-state [Ca(2+)](i) measured at 300 s of depolarization was higher in control cells compared with cells in which the ER Ca(2+) pools were depleted. The amount of Ca(2+) presented to the cytoplasm during depolarization as estimated from the integral of the increment in [Ca(2+)](i) over time (integralDelta[Ca(2+)](i).dt) was approximately 30% higher compared with that in the Ca(2+) pool-depleted cells. neo-thapsigargin, an inactive analog, did not affect [Ca(2+)](i) response. Using Sr(2+) in the extracellular medium and exploiting the differences in the fluorescence properties of Ca(2+)- and Sr(2+)-bound fluo-3, we found that the incoming Sr(2+) triggered Ca(2+) release from the ER. Depolarization-induced [Ca(2+)](i) response was not altered by, an inhibitor of phosphatidylinositol-specific phospholipase C, suggesting that stimulation of the enzyme by Ca(2+) is not essential for amplification of Ca(2+) signaling. [Ca(2+)](i) response was enhanced when cells were depolarized in the presence of 3 mm glucose, forskolin, and caffeine, suggesting involvement of ryanodine receptors in the amplification process. Pretreatment with ryanodine (100 microm) diminished the second phase of the depolarization-induced increase in [Ca(2+)](i). We conclude that Ca(2+) entry through L-type voltage-gated Ca(2+) channels triggers Ca(2+) release from the ER and that such a process amplifies depolarization-induced Ca(2+) signaling in beta-cells.

Distribution, cloning, and characterization of porcine nucleoside triphosphate diphosphohydrolase-1

In this study, we have investigated the distribution of the enzyme nucleoside triphosphate diphosphohydrolase-1 (NTPDase1; EC 3.6.1.5) in a subset of pig tissues by biochemical activity and Western blotting with antibodies against porcine NTPDase1. The highest expression of this enzyme was found in vascular endothelium, smooth muscle, spleen and lung. The complete cDNA of NTPDase1 from aorta endothelial cells was sequenced using primer walking. The protein consists of 510 amino acids, with a calculated molecular mass of 57 756 Da. The amino-acid sequence indicated seven putative N-glycosylation sites and one potential intracellular cGMP- and cAMP-dependent protein kinase phosphorylation site. As expected, the protein has a very high homology to other known mammalian ATPDases and CD39 molecules, and includes all five apyrase conserved regions. Expression of the complete cDNA in COS-7 cells confirmed that NTPDase1 codes for a transmembrane glycoprotein with ecto-ATPase and ecto-ADPase activities. Two proteolytic products of NTPDase1, with molecular mass of 54 and 27 kDa, respectively, were consistently present in proteins from transfected COS-7 cells and in particulate fractions from different tissues. A trypsin cleavage site, giving rise to these two cleavage products, was identified. In order to remain enzymatically active, the two cleavage products have to interact by non-covalent interactions.

Purification, characterization, and localization of an ATP diphosphohydrolase in porcine kidney

Membranes of pig kidney cortex tissue were solubilized in the presence of Triton X-100. Partial purification of ATP diphosphohydrolase (ATPDase) was achieved by successive chromatography on concanavalin A-Sepharose, Q-Sepharose Fast Flow, and 5'-AMP-Sepharose 4B. Monoclonal antibodies against ATPDase were generated. Further purification of the ATPDase was obtained by immunoaffinity chromatography with these monoclonal antibodies. NH(2)-terminal amino acid sequencing of the 78-kDa protein showed a sequence very homologous to mammalian CD39. The protein is highly glycosylated, with a nominal molecular mass of approximately 57 kDa. The purified enzyme hydrolyzed di- and triphosphates of adenosine, guanosine, cytidine, uridine, inosine, and thymidine, but AMP and diadenosine polyphosphates could not serve as substrates. All enzyme activities were dependent on divalent cations and were partially inhibited by 10 mM sodium azide. The distribution of the enzyme in pig kidney cortex was examined immunohistochemically. The enzyme was found to be present in blood vessel walls of glomerular and peritubular capillaries.

Identification and characterization of a novel hepatic canalicular ATP diphosphohydrolase

We have identified and characterized a novel ATP diphosphohydrolase (ATPDase) with features of E-type ATPases from porcine liver. Immunoblotting with a specific monoclonal antibody to this ectoenzyme revealed high expression in liver with lesser amounts in kidney and duodenum. This ATPDase was localized by immunohistochemistry to the bile canalicular domain of hepatocytes and to the luminal side of the renal ductular epithelium. In contrast, ATPDase/cd39 was detected in vascular endothelium and smooth muscle in these organs. We purified the putative ATPDase from liver by immunoaffinity techniques and obtained a heavily glycosylated protein with a molecular mass estimated at 75 kDa. This enzyme hydrolyzed all tri- and diphosphonucleosides but not AMP or diadenosine polyphosphates. There was an absolute requirement for divalent cations (Ca(2+) > Mg(2+)). Biochemical activity was unaffected by sodium azide or other inhibitors of ATPases. Kinetic parameters derived from purified preparations of hepatic ATPDase indicated V(max) of 8.5 units/mg of protein with apparent K(m) of 100 microM for both ATP or ADP as substrates. NH(2)-terminal amino acid sequencing revealed near 50% identity with rat liver lysosomal (Ca(2+)-Mg(2+))-ATPase. The different biochemical properties and localization of the hepatic ATPDase suggest pathophysiological functions that are distinct from the vascular ATPDase/cd39.

Regulation of proliferation of LLC-MK2 cells by nucleosides and nucleotides: the role of ecto-enzymes

1. Using the incorporation of [methyl-3H]thymidine as a proliferation marker, the effects of various nucleosides and nucleotides on endothelial LLC-MK2 cells were studied. We found that ATP, ADP, AMP and adenosine in concentrations of 10 microM or higher stimulate the proliferation of these cells. 2. Inhibition of ecto-ATPase (EC 3.6.1.15), 5'-nucleotidase (EC 3.1.3.5) or alkaline phosphatase (EC 3.1.3.1) significantly diminished the stimulatory effect of ATP, indicating that the effect is primarily caused by adenosine and not by adenine nucleotides. Also, the effect depends only on extracellular nucleosides, since inhibition of nucleoside uptake by dipyridamole has no influence on proliferation. 3. Other purine nucleotides and nucleosides (ITP, GTP, inosine and guanosine) also stimulate cell proliferation, while pyrimidine nucleotides and nucleosides (CTP, UTP, cytidine and uridine) inhibit proliferation. Furthermore, the simultaneous presence of adenosine and any of the other purine nucleosides is not entirely additive in its effect on cell proliferation. At the same time any pyrimidine nucleoside, when added together with adenosine, has the same inhibitory effect as the pyrimidine nucleoside alone. 4. Apparently these proliferative effects are neither caused by any pharmacologically known P1-purinoceptor, nor are they mediated by cyclic AMP, cyclic GMP, or D-myo-inositol 1,4,5-trisphosphate as second messenger, nor by extracellular Ca2+. 5. Therefore, we conclude that various purine and pyrimidine nucleosides can influence the proliferation of LLC-MK2 cells by acting on putative purinergic and pyrimidinergic receptors not previously described.

Autoradiography-based cytochemical detection of ecto-ATPase, ecto-ADPase, 5'-nucleotidase, and extracellular adenosine production, employing 141Ce3+ as a capturing agent

A method for the visualization of the ecto-nucleotidase enzyme activities present on the cell surface, employing 141Ce3+ as a capturing and labelling agent, is described. Phosphate ions precipitated at the cell surface can be detected by coating the cells with an autoradiographic emulsion, followed by light microscopical inspection of the formed silver grains. The activities of ecto-ATPase, ecto-ADPase and 5'-nucleotidase were detected by this approach in four different cell lines. Parallel biochemical measurements of the activities of the corresponding enzymes were carried out in order to validate, evaluate, and optimize the cytochemical detection. The finding that Ce3+ ions are inhibitory to ecto-ATPase provided evidence for the necessity of carefully establishing appropriate reaction conditions for the cytochemical determination of ecto-nucleotidases. The application of this method to the indirect detection of extracellular adenosine production from substrates like ATP has also been documented. It allows a cytochemical determination of adenosine formed through cascade nucleotide dephosphorylation. This newly described method is of high sensitivity and potentially of value for a variety of applications, including not only cytochemistry but also cell biology, and molecular biology studies.

Identification and partial purification of (Ca2+ or Mg2+)-ATPase in renal brush-border membranes

The protein responsible for the (Ca2+ or Mg2+)-ATPase activity in brush-border membranes from pig kidney tubular cells was characterized to distinguish this enzyme from the N-ethylmaleimide-sensitive Mg(2+)-ATPase, also present in renal brush borders. Both enzymes are clearly different in their pH optimum and their sensitivity to divalent cations, nucleoside 5'-triphosphates and inhibitors. Solubilization of the (Ca2+ or Mg2+)-ATPase from brush-border membrane vesicles was accomplished with Nonidet P-40 or dodecylmaltoside. However, simultaneous inactivation of the enzyme was inevitable. A tenfold enrichment of the ATPase activity was obtained by chromatofocusing of Nonidet-P-40-solubilized brush borders. A similar degree of purification was achieved by ion-exchange chromatography of dodecylmaltoside-solubilized preparations. From the SDS/polyacrylamide gels of partially purified (Ca2+ or Mg2+)-ATPase, a few protein bands could still be tentatively identified as responsible for the enzyme activity. Labeling of solubilized brush-border preparations with several radioactive ATP analogues also revealed that a protein band of molecular mass 90 kDa is the most probable candidate for the catalytic peptide of the (Ca2+ or Mg2+)-ATPase. Finally, immunoprecipitation as well as semi-dry blotting with antibodies generated against partially purified enzyme preparations, confirmed that a 90-kDa component is a reasonable candidate for the (Ca2+ or Mg2+)-ATPase in renal brush-border membranes.