Synthesising the evidence for effective hand hygiene in community settings: an integrated protocol for multiple related systematic reviews.

INTRODUCTION: Despite evidence for the efficacy and effectiveness of hand hygiene in reducing the transmission of infectious diseases, there are gaps in global normative guidance around hand hygiene in community settings. The goal of this review is to systematically retrieve and synthesise available evidence on hand hygiene in community settings across four areas: (1) effective hand hygiene; (2) minimum requirements; (3) behaviour change and (4) government measures. METHODS AND ANALYSIS: This protocol entails a two-phased approach to identify relevant studies for multiple related systematic reviews. Phase 1 involves a broad search to capture all studies on hand hygiene in community settings. Databases, trial registries, expert consultations and hand searches of reference lists will be used to ensure an exhaustive search. A comprehensive, electronic search strategy will be used to identify studies indexed in PubMed, Web of Science, EMBASE, CINAHL, Global Health, Cochrane Library, Global Index Medicus, Scopus, PAIS Index, WHO IRIS, UN Digital Library and World Bank eLibrary published in English from January 1980 to March 2023. The outcome of phase 1 will be a reduced sample of studies from which further screening, specific to research questions across the four key areas can be performed. Two reviewers will independently assess each study for inclusion and disagreements will be resolved by a third reviewer. Quantitative and qualitative data will be extracted following best practices. We will assess all studies using the Mixed Method Appraisal Tool. All effect measures pertaining to review outcomes will be reported and a narrative synthesis of all studies will be presented including 'data-driven' descriptive themes and 'theory-driven' analytical themes as applicable. ETHICS AND DISSEMINATION: This systematic review is exempt from ethics approval because the work is carried out on published documents. The findings of the reviews will be disseminated in related peer-reviewed journals. PROSPERO REGISTRATION NUMBER: CRD42023429145.

Quantifying Factors Associated with Personal Hygiene as Measured by the qPHAT Methodology: Andilaye Trial, Ethiopia.

Many water, sanitation, and hygiene (WASH) interventions target improvements in personal hygiene behaviors. Yet measuring personal hygiene behaviors is a challenge due to a lack of reliable, valid, objective, and simple-to-use approaches. The purpose of this study was to examine differences between two types of hygiene outcome measures and their ability to detect relationships between WASH-related behavioral factors and behaviors. We compared hygiene outcomes generated by the Quantitative Personal Hygiene Assessment Tool (qPHAT), which yields objective measures of cleanliness on an 11-point scale, and those generated by conventional, dichotomous indicators of cleanliness. We used cross-sectional data on hygiene outcomes related to facial and hand cleanliness collected during the Andilaye Trial, an impact evaluation of a community-based WASH intervention implemented in Amhara, Ethiopia. We fit multivariable models to examine associations between measures of children's facial and hand cleanliness, via both qPHAT and dichotomous indicators, and 1) household WASH conditions, 2) psychosocial factors, and 3) reported personal hygiene practices. The qPHAT-generated outcomes were able to detect relationships between intermediate behavioral factors and hygiene outcomes that dichotomous indicators were not, including associations with water insecurity and various psychosocial factors. qPHAT-generated outcomes were negatively associated with reported face washing practices, suggesting a bias in reported behaviors. Our study highlights the limitations of reported practices and dichotomous hygiene indicators and indicates that using more quantitative hygiene outcome measures, such as those generated by qPHAT, may reveal important intermediate factors that influence hygiene behavior and support improved monitoring and evaluation of interventions.

Study design and rationale for the PAASIM project: a matched cohort study on urban water supply improvements and infant enteric pathogen infection, gut microbiome development and health in Mozambique.

INTRODUCTION: Despite clear linkages between provision of clean water and improvements in child health, limited information exists about the health impacts of large water infrastructure improvements in low-income settings. Billions of dollars are spent annually to improve urban water supply, and rigorous evaluation of these improvements, especially targeting informal settlements, is critical to guide policy and investment strategies. Objective measures of infection and exposure to pathogens, and measures of gut function, are needed to understand the effectiveness and impact of water supply improvements. METHODS AND ANALYSIS: In the PAASIM study, we examine the impact of water system improvements on acute and chronic health outcomes in children in a low-income urban area of Beira, Mozambique, comprising 62 sub-neighbourhoods and ~26 300 households. This prospective matched cohort study follows 548 mother-child dyads from late pregnancy through 12 months of age. Primary outcomes include measures of enteric pathogen infections, gut microbiome composition and source drinking water microbiological quality, measured at the child's 12-month visit. Additional outcomes include diarrhoea prevalence, child growth, previous enteric pathogen exposure, child mortality and various measures of water access and quality. Our analyses will compare (1) subjects living in sub-neighbourhoods with the improved water to those living in sub-neighbourhoods without these improvements; and (2) subjects with household water connections on their premises to those without such a connection. This study will provide critical information to understand how to optimise investments for improving child health, filling the information gap about the impact of piped water provision to low-income urban households, using novel gastrointestinal disease outcomes. ETHICS AND DISSEMINATION: This study was approved by the Emory University Institutional Review Board and the National Bio-Ethics Committee for Health in Mozambique. The pre-analysis plan is published on the Open Science Framework platform (https://osf.io/4rkn6/). Results will be shared with relevant stakeholders locally, and through publications.

Spatial heterogeneity of neighborhood-level water and sanitation access in informal urban settlements: A cross-sectional case study in Beira, Mozambique.

Rapid urbanization, resulting in population growth within informal settlements, has worsened exclusion and inequality in access to water and sanitation (WASH) services in the poorest and most marginalized communities. In this study, we describe the heterogeneity in water service satisfaction and WASH access in low-income, peri-urban neighborhoods of Beira, Mozambique, and examine whether this heterogeneity can be explained by distance to water distribution mains. Using spatial statistics and regression analyses, we identify spatial heterogeneity in household WASH access, as well as consumer-reported satisfaction with water services (services, pressure, quality, and sufficient quantity). We find that as distance from the water main increased, both access to an improved water source at the household and satisfaction with water pressure decreases, and water supply intermittency increases, controlling for household density and socioeconomic status. The odds of a household having access to a water source at the household or on the compound decreases with every 100-meter increase in distance from a water main pipe (odds ratio [OR] 0.87, 95% confidence interval [CI]: 0.82, 0.92). Satisfaction with water services also decreases with every 100-meter increase in distance from a water main pipe (OR: 0.80; 95% CI: 0.69, 0.94). Days of availability in the past week decreases by a factor of 0.22 for every 100-meter increase in distance from the water main (95% CI: -0.29, -0.15). Findings from this study highlight the unequal household access to water and sanitation in urban informal settlements, even within low-income neighborhoods. Describing this heterogeneity of access to water services, sanitation, and satisfaction-and the factors influencing them-can inform stakeholders and guide the development of infrastructural solutions to reduce water access inequities within urban settings.

Assessing Sustainability Factors for Rural Household Sanitation Coverage in Bhutan, Kenya, Nepal, and Zambia: A Qualitative Analysis.

BACKGROUND: Few countries are likely to achieve universal sanitation within the next decade as sustaining household sanitation coverage remains a critical challenge. This study aimed to investigate factors that may have supported or hindered sustainability of sanitation coverage 1-2 years after the completion of an integrated, area-wide sanitation program in 4 countries. METHODS: We conducted qualitative analyses to identify factors related to the sustainability of sanitation coverage in Bhutan, Kenya, Nepal, and Zambia, 2 years after completion of the Sustainable Sanitation and Hygiene for All program. From November 2019 to March 2020, we conducted focus group discussions and key informant interviews with community members, project implementers, and decision makers. We triangulated the qualitative findings with data from household surveys to characterize subnational sanitation coverage throughout implementation and 1-2 years after. RESULTS: Our data revealed behavioral, contextual, and service delivery factors that were related to the sustainability of sanitation improvements. Service delivery factors included follow-up hygiene promotion, access to construction materials, local government commitment postimplementation, functioning monitoring systems, private sector uptake of supply chain improvements, and capacity for innovation. Contextual and behavioral factors included poverty, soil type, road networks, social cohesion, desire for improved latrines, maintenance and cleaning, and knowledge of sanitation benefits. CONCLUSION: The presence or absence of sustainability factors identified through this research may have implications on where certain programmatic approaches will work and where adaptations may be required. By comparing sustainability factors with subnational slippage rates, we were able to illustrate how local service delivery systems may respond to barriers and enablers. Understanding the programmatic and contextual factors that either drive or hinder long-term sanitation coverage may allow for greater program impact through adapting implementation based on existing challenges in service delivery and context.

The impact of a demand-side sanitation and hygiene promotion intervention on sustained behavior change and health in Amhara, Ethiopia: A cluster-randomized trial.

Behaviors related to water, sanitation, and hygiene (WASH) are key drivers of infectious disease transmission, and experiences of WASH are potential influencers of mental well-being. Important knowledge gaps exist related to the content and delivery of effective WASH programs and their associated health impacts, particularly within the contexts of government programs implemented at scale. We developed and tested a demand-side intervention called Andilaye, which aimed to change behaviors related to sanitation, personal hygiene, and household environmental sanitation. This theory-informed intervention was delivered through the existing Ethiopian Health Extension Programme (HEP). It was a multilevel intervention with a catalyzing event at the community level and behavior change activities at group and household levels. We randomly selected and assigned 50 kebeles (sub-districts) from three woredas (districts), half to receive the Andilaye intervention, and half the standard of care sanitation and hygiene programming (i.e., community-led total sanitation and hygiene [CLTSH]). We collected data on WASH access, behavioral outcomes, and mental well-being. A total of 1,589 households were enrolled into the study at baseline; 1,472 households (94%) participated in an endline assessment two years after baseline, and approximately 14 months after the initiation of a multi-level intervention. The intervention did not improve construction of latrines (prevalence ratio [PR]: 0.99; 95% CI: 0.82, 1.21) or handwashing stations with water (PR: 0.96; 95% CI: 0.72, 1.26), or the removal of animal feces from the compound (PR: 1.10; 95% CI: 0.95, 1.28). Nor did it impact anxiety (PR: 0.90; 95% CI: 0.72, 1.11), depression (PR: 0.83; 95% CI: 0.64, 1.07), emotional distress (PR: 0.86; 95% CI: 0.67, 1.09) or well-being (PR: 0.90; 95% CI: 0.74, 1.10) scores. We report limited impact of the intervention, as delivered, on changes in behavior and mental well-being. The effectiveness of the intervention was limited by poor intervention fidelity. While sanitation and hygiene improvements have been documented in Ethiopia, behavioral slippage, or regression to unimproved practices, in communities previously declared open defecation free is widespread. Evidence from this trial may help address knowledge gaps related to challenges associated with scalable alternatives to CLTSH and inform sanitation and hygiene programming and policy in Ethiopia and beyond. Trial registration: This trial was registered with clinicaltrials.gov (NCT03075436) on March 9, 2017.

The Sustainability and Scalability of Private Sector Sanitation Delivery in Urban Informal Settlement Schools: A Mixed Methods Follow Up of a Randomized Trial in Nairobi, Kenya.

There are considerable challenges to achieving the Sustainable Development Goals' target of universal access to basic sanitation in schools. Schools require safe, clean, and sex-segregated facilities for a large number of students. Robust and affordable solutions are needed to address the economic, spatial, social, institutional, and political factors which contribute to poor sanitary conditions in informal settlements. In 2015, we undertook a randomized controlled trial to assess the feasibility of private sector sanitation delivery (PSSD) in 20 primary schools, in informal settlements of Nairobi, Kenya. Our preliminary evaluation after one year of service delivery suggested that PSSD of urine-diverting dry latrines with routine waste collection and maintenance provided a feasible, lower-cost alternative to the government standard delivery (GSD) of cistern-flush toilets or ventilated improved pit latrines. We conducted a mixed-methods follow-up study to assess sanitation delivery over 3-4 years and investigate prevailing drivers and barriers that may influence the scalability of PSSD. The conditions of newly constructed and rehabilitated GSD facilities diminished quickly, reverting to the conditions of existing facilities, indicating lower sustainability compared to sanitation delivered from the private sector. Barriers in financial aspects related to the ongoing implementation of PSSD emerged, particularly among public schools, and few were able to pay for continued service. Our study demonstrates that the engagement of the private sector may lead to improvements in affordable, safely managed sanitation for schools and their students. Yet, to reach a sustained scale, additional guidance is needed on how to develop these partnerships, streamline procurement and contracting processes, and incorporate appropriate financing mechanisms.

Development and reliability of a quantitative personal hygiene assessment tool.

Personal hygiene practices, including facewashing and handwashing, reduce transmission of pathogens, but are difficult to measure. Using color theory principles, we developed and tested a novel metric that generates quantitative measures of facial and hand cleanliness, proxy indicators of personal hygiene practices. In this cross-sectional study, conventional qualitative cleanliness metrics (e.g., presence or absence of nasal and ocular discharge, dirt under nails or on finger pads and palms) were also recorded. We generated Gwet's agreement coefficients to determine the inter-rater reliability of novel and conventional metrics between various rating groups, where appropriate, including two non-blinded raters, non-blinded vs. blinded raters, three blinded raters, and blinded vs. computer raters. Inter-rater reliability of the novel metric was high across all rating groups, ranging from 0.98 (95% CI: 0.97, 0.99) to 0.90 (95% CI: 0.90, 0.91) for facial cleanliness, and 0.97 (95% CI: 0.96, 0.98) to 0.92 (95% CI: 0.91, 0.93) for hand cleanliness. Our novel metric generates more nuanced data than conventional qualitative metrics, and allows for quantifiable assessments of facial and hand cleanliness.

Design of a parallel cluster-randomized trial assessing the impact of a demand-side sanitation and hygiene intervention on sustained behavior change and mental well-being in rural and peri-urban Amhara, Ethiopia: Andilaye study protocol.

BACKGROUND: Unimproved water, sanitation, and hygiene (WASH) behaviors are key drivers of infectious disease transmission and influencers of mental well-being. While WASH is seen as a critical enabler of health, important knowledge gaps related to the content and delivery of effective, holistic WASH programming exist. Corresponding impacts of WASH on mental well-being are also underexplored. There is a need for more robust implementation research that yields information regarding whether and how community-based, demand-side interventions facilitate progressive and sustained adoption of improved sanitation and hygiene behaviors and downstream health impacts. The purpose of this protocol is to detail the rationale and design of a cluster-randomized trial evaluating the impact of a demand-side sanitation and hygiene intervention on sustained behavior change and mental well-being in rural and peri-urban Amhara, Ethiopia. METHODS: Together with partners, we developed a theoretically-informed, evidence-based behavioral intervention called Andilaye. We randomly selected and assigned 50 sub-districts (kebeles) from three purposively selected districts (woredas); half to receive the Andilaye intervention, and half the standard of care sanitation and hygiene programming (i.e., community-led total sanitation and hygiene [CLTSH]). During baseline, midline, and endline, we will collect data on an array of behavioral factors, potential moderators (e.g., water and sanitation insecurity, collective efficacy), and our primary study outcomes: sanitation and hygiene behaviors and mental well-being. We will perform a process evaluation to assess intervention fidelity and related attributes. DISCUSSION: While CLTSH has fostered sanitation and hygiene improvements in Ethiopia, evidence of behavioral slippage, or regression to unimproved practices in communities previously declared open defecation free exists. Other limitations of CLTSH, such as its focus on disgust, poor triggering, and over-saturation of Health Extension Workers have been documented. We employed rigorous formative research and practically applied social and behavioral theory to develop Andilaye, a scalable intervention designed to address these issues and complement existing service delivery within Ethiopia's Health Extension Program. Evidence from this trial may help address knowledge gaps related to scalable alternatives to CLTSH and inform sanitation and hygiene programming and policy in Ethiopia and beyond. TRIAL REGISTRATION: This trial was registered with clinicaltrials.gov ( NCT03075436 ) on March 9, 2017.

ß(IV)-Spectrin regulates TREK-1 membrane targeting in the heart.

AIMS: Cardiac function depends on the highly regulated and co-ordinate activity of a large ensemble of potassium channels that control myocyte repolarization. While voltage-gated K(+) channels have been well characterized in the heart, much less is known about regulation and/or targeting of two-pore K(+) channel (K(2P)) family members, despite their potential importance in modulation of heart function. METHODS AND RESULTS: Here, we report a novel molecular pathway for membrane targeting of TREK-1, a mechano-sensitive K(2P) channel regulated by environmental and physical factors including membrane stretch, pH, and polyunsaturated fatty acids (e.g. arachidonic acid). We demonstrate that ß(IV)-spectrin, an actin-associated protein, is co-localized with TREK-1 at the myocyte intercalated disc, associates with TREK-1 in the heart, and is required for TREK-1 membrane targeting. Mice expressing ß(IV)-spectrin lacking TREK-1 binding (qv(4J)) display aberrant TREK-1 membrane localization, decreased TREK-1 activity, delayed action potential repolarization, and arrhythmia without apparent defects in localization/function of other cardiac potassium channel subunits. Finally, we report abnormal ß(IV)-spectrin levels in human heart failure. CONCLUSIONS: These data provide new insight into membrane targeting of TREK-1 in the heart and establish a broader role for ß(IV)-spectrin in organizing functional membrane domains critical for normal heart function.

Ryanodine receptor phosphorylation by oxidized CaMKII contributes to the cardiotoxic effects of cardiac glycosides.

AIMS: Recent studies suggest that proarrhythmic effects of cardiac glycosides (CGs) on cardiomyocyte Ca(2+) handling involve generation of reactive oxygen species (ROS). However, the specific pathway(s) of ROS production and the subsequent downstream molecular events that mediate CG-dependent arrhythmogenesis remain to be defined. METHODS AND RESULTS: We examined the effects of digitoxin (DGT) on Ca(2+) handling and ROS production in cardiomyocytes using a combination of pharmacological approaches and genetic mouse models. Myocytes isolated from mice deficient in NADPH oxidase type 2 (NOX2KO) and mice transgenically overexpressing mitochondrial superoxide dismutase displayed markedly increased tolerance to the proarrhythmic action of DGT as manifested by the inhibition of DGT-dependent ROS and spontaneous Ca(2+) waves (SCW). Additionally, DGT-induced mitochondrial membrane potential depolarization was abolished in NOX2KO cells. DGT-dependent ROS was suppressed by the inhibition of PI3K, PKC, and the mitochondrial KATP channel, suggesting roles for these proteins, respectively, in activation of NOX2 and in mitochondrial ROS generation. Western blot analysis revealed increased levels of oxidized CaMKII in WT but not in NOX2KO hearts treated with DGT. The DGT-induced increase in SCW frequency was abolished in myocytes isolated from mice in which the Ser 2814 CaMKII phosphorylation site on RyR2 is constitutively inactivated. CONCLUSION: These results suggest that the arrhythmogenic adverse effects of CGs on Ca(2+) handling involve PI3K- and PKC-mediated stimulation of NOX2 and subsequent NOX2-dependent ROS release from the mitochondria; mitochondria-derived ROS then activate CaMKII with consequent phosphorylation of RyR2 at Ser 2814.

Ca2+/calmodulin-dependent protein kinase II-based regulation of voltage-gated Na+ channel in cardiac disease.

BACKGROUND: Human gene variants affecting ion channel biophysical activity and/or membrane localization are linked to potentially fatal cardiac arrhythmias. However, the mechanism for many human arrhythmia variants remains undefined despite more than a decade of investigation. Posttranslational modulation of membrane proteins is essential for normal cardiac function. Importantly, aberrant myocyte signaling has been linked to defects in cardiac ion channel posttranslational modifications and disease. We recently identified a novel pathway for posttranslational regulation of the primary cardiac voltage-gated Na(+) channel (Na(v)1.5) by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). However, a role for this pathway in cardiac disease has not been evaluated. METHODS AND RESULTS: We evaluated the role of CaMKII-dependent phosphorylation in human genetic and acquired disease. We report an unexpected link between a short motif in the Na(v)1.5 DI-DII loop, recently shown to be critical for CaMKII-dependent phosphorylation, and Na(v)1.5 function in monogenic arrhythmia and common heart disease. Experiments in heterologous cells and primary ventricular cardiomyocytes demonstrate that the human arrhythmia susceptibility variants (A572D and Q573E) alter CaMKII-dependent regulation of Na(v)1.5, resulting in abnormal channel activity and cell excitability. In silico analysis reveals that these variants functionally mimic the phosphorylated channel, resulting in increased susceptibility to arrhythmia-triggering afterdepolarizations. Finally, we report that this same motif is aberrantly regulated in a large-animal model of acquired heart disease and in failing human myocardium. CONCLUSIONS: We identify the mechanism for 2 human arrhythmia variants that affect Na(v)1.5 channel activity through direct effects on channel posttranslational modification. We propose that the CaMKII phosphorylation motif in the Na(v)1.5 DI-DII cytoplasmic loop is a critical nodal point for proarrhythmic changes to Na(v)1.5 in congenital and acquired cardiac disease.

Differential regulation of EHD3 in human and mammalian heart failure.

Electrical and structural remodeling during the progression of cardiovascular disease is associated with adverse outcomes subjecting affected patients to overt heart failure (HF) and/or sudden death. Dysfunction in integral membrane protein trafficking has long been linked with maladaptive electrical remodeling. However, little is known regarding the molecular identity or function of these intracellular targeting pathways in the heart. Eps15 homology domain-containing (EHD) gene products (EHD1-4) are polypeptides linked with endosomal trafficking, membrane protein recycling, and lipid homeostasis in a wide variety of cell types. EHD3 was recently established as a critical mediator of membrane protein trafficking in the heart. Here, we investigate the potential link between EHD3 function and heart disease. Using four different HF models including ischemic rat heart, pressure overloaded mouse heart, chronic pacing-induced canine heart, and non-ischemic failing human myocardium we provide the first evidence that EHD3 levels are consistently increased in HF. Notably, the expression of the Na/Ca exchanger (NCX1), targeted by EHD3 in heart is similarly elevated in HF. Finally, we identify a molecular pathway for EHD3 regulation in heart failure downstream of reactive oxygen species and angiotensin II signaling. Together, our new data identify EHD3 as a previously unrecognized component of the cardiac remodeling pathway.

A ß(IV)-spectrin/CaMKII signaling complex is essential for membrane excitability in mice.

Ion channel function is fundamental to the existence of life. In metazoans, the coordinate activities of voltage-gated Na(+) channels underlie cellular excitability and control neuronal communication, cardiac excitation-contraction coupling, and skeletal muscle function. However, despite decades of research and linkage of Na(+) channel dysfunction with arrhythmia, epilepsy, and myotonia, little progress has been made toward understanding the fundamental processes that regulate this family of proteins. Here, we have identified ß(IV)-spectrin as a multifunctional regulatory platform for Na(+) channels in mice. We found that ß(IV)-spectrin targeted critical structural and regulatory proteins to excitable membranes in the heart and brain. Animal models harboring mutant ß(IV)-spectrin alleles displayed aberrant cellular excitability and whole animal physiology. Moreover, we identified a regulatory mechanism for Na(+) channels, via direct phosphorylation by ß(IV)-spectrin-targeted calcium/calmodulin-dependent kinase II (CaMKII). Collectively, our data define an unexpected but indispensable molecular platform that determines membrane excitability in the mouse heart and brain.

EH domain proteins regulate cardiac membrane protein targeting.

RATIONALE: Cardiac membrane excitability is tightly regulated by an integrated network of membrane-associated ion channels, transporters, receptors, and signaling molecules. Membrane protein dynamics in health and disease are maintained by a complex ensemble of intracellular targeting, scaffolding, recycling, and degradation pathways. Surprisingly, despite decades of research linking dysfunction in membrane protein trafficking with human cardiovascular disease, essentially nothing is known regarding the molecular identity or function of these intracellular targeting pathways in excitable cardiomyocytes. OBJECTIVE: We sought to discover novel pathways for membrane protein targeting in primary cardiomyocytes. METHODS AND RESULTS: We report the initial characterization of a large family of membrane trafficking proteins in human heart. We used a tissue-wide screen for novel ankyrin-associated trafficking proteins and identified 4 members of a unique Eps15 homology (EH) domain-containing protein family (EHD1, EHD2, EHD3, EHD4) that serve critical roles in endosome-based membrane protein targeting in other cell types. We show that EHD1-4 directly associate with ankyrin, provide the first information on the expression and localization of these molecules in primary cardiomyocytes, and demonstrate that EHD1-4 are coexpressed with ankyrin-B in the myocyte perinuclear region. Notably, the expression of multiple EHD proteins is increased in animal models lacking ankyrin-B, and EHD3-deficient cardiomyocytes display aberrant ankyrin-B localization and selective loss of Na/Ca exchanger expression and function. Finally, we report significant modulation of EHD expression following myocardial infarction, suggesting that these proteins may play a key role in regulating membrane excitability in normal and diseased heart. CONCLUSIONS: Our findings identify and characterize a new class of cardiac trafficking proteins, define the first group of proteins associated with the ankyrin-based targeting network, and identify potential new targets to modulate membrane excitability in disease. Notably, these data provide the first link between EHD proteins and a human disease model.

Regulation of the ankyrin-B-based targeting pathway following myocardial infarction.

AIMS: Ion channel reorganization is a critical step in the pro-arrhythmogenic remodelling process that occurs in heart disease. Ankyrin-B (AnkB) is required for targeting and stabilizing ion channels, exchangers, and pumps. Despite a wealth of knowledge implicating the importance of AnkB in human cardiovascular physiology, nothing is known regarding the role of AnkB in common forms of acquired human disease. METHODS AND RESULTS: We present the first report of AnkB regulation following myocardial infarction (MI). AnkB protein levels were reduced in the infarct border zone 5 days following coronary artery occlusion in the canine. We also observed a dramatic increase in AnkB mRNA levels 5 days post-occlusion. Surprisingly, the expression of the upstream AnkB cytoskeletal component beta2-spectrin was unchanged in post-infarct tissues. However, protein levels and/or membrane expression of downstream AnkB-associated ion channels and transporters Na+/K+ ATPase, Na+/Ca2+ exchanger, and IP3 receptor were altered 5 days post-occlusion. Interestingly, protein levels of the protein phosphatase 2A, an AnkB-associated signalling protein, were significantly affected 5 days post-occlusion. AnkB and PP2A protein levels recovered by 14 days post-occlusion, whereas Na+/K+ ATPase levels recovered by 2 months post-occlusion. CONCLUSION: These findings reveal the first evidence of ankyrin remodelling following MI and suggest an unexpected divergence point for regulation between ankyrin and the underlying cytoskeletal network. These findings suggest a logical, but unexpected, molecular mechanism underlying ion channel and transporter remodelling following MI.