Browsing by Author "Walsh, Michael"
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- ItemOpen AccessA cluster randomized controlled trial for the Evaluation of routinely Measured PATient reported outcomes in HemodialYsis care (EMPATHY): a study protocol(2020-08-10) Johnson, Jeffrey A; Al Sayah, Fatima; Buzinski, Robert; Corradetti, Bonnie; Davison, Sara N; Elliott, Meghan J; Klarenbach, Scott; Manns, Braden; Schick-Makaroff, Kara; Short, Hilary; Thomas, Chandra; Walsh, MichaelAbstract Background Kidney failure requiring dialysis is associated with poor health outcomes and health-related quality of life (HRQL). Patient-reported outcome measures (PROMs) capture symptom burden, level of functioning and other outcomes from a patient perspective, and can support clinicians to monitor disease progression, address symptoms, and facilitate patient-centered care. While evidence suggests the use of PROMs in clinical practice can lead to improved patient experience in some settings, the impact on patients’ health outcomes and experiences is not fully understood, and their cost-effectiveness in clinical settings is unknown. This study aims to fill these gaps by evaluating the effectiveness and cost-effectiveness of routinely measuring PROMs on patient-reported experience, clinical outcomes, HRQL, and healthcare utilization. Methods The EMPATHY trial is a pragmatic multi-centre cluster randomized controlled trial that will implement and evaluate the use of disease-specific and generic PROMs in three kidney care programs in Canada. In-centre hemodialysis units will be randomized into four groups, whereby patients: 1) complete a disease-specific PROM; 2) complete a generic PROM; 3) complete both types of PROMs; 4) receive usual care and do not complete any PROMs. While clinical care pathways are available to all hemodialysis units in the study, for the three active intervention groups, the results of the PROMs will be linked to treatment aids for clinicians and patients. The primary outcome of this study is patient-provider communication, assessed by the Communication Assessment Tool (CAT). Secondary outcomes include patient management and symptoms, use of healthcare services, and the costs of implementing this intervention will also be estimated. The present protocol fulfilled the Standard Protocol Items: Recommendations for Intervention Trials (SPIRIT) checklist. Discussion While using PROMs in clinical practice is supported by theory and rationale, and may engage patients and enhance their role in decisions regarding their care and outcomes, the best approach of their use is still uncertain. It is important to rigorously evaluate such interventions and investments to ensure they provide value for patients and health systems. Trial registration Protocol version (1.0) and trial registration data are available on www.clinicaltrials.gov , identifier: NCT03535922 , registered May 24, 2018.
- ItemOpen AccessAssociation between routine and standardized blood pressure measurements and left ventricular hypertrophy among patients on hemodialysis(BioMed Central, 2010-06-24) Khangura, Jaspreet; Culleton, Bruce F.; Manns, Braden J.; Zhang, Jianguo; Barnieh, Lianne; Walsh, Michael; Klarenbach, Scott W.; Tonelli, Marcello; Sarna, Magdalena; Hemmelgarn, Brenda R.
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- ItemOpen AccessIdentification and Characterization of a Novel Tyrosine Phosphatase in Plants(2017) Labandera, Anne Marie Lyse; Moorhead, Gregory; Samuel, Marcus; Fraser, Marie; Walsh, Michael; Ellis, BrianThe study of tyrosine phosphorylation in plants has been largely neglected due to the lack of classic tyrosine kinases and underrepresentation of tyrosine phosphatases compared to humans. However, advanced phosphoproteomics studies have revealed that the abundance of phospho-tyrosine residues in plants parallels human signal transduction. This strongly suggests that in plants tyrosine phosphorylation is as important as in humans, yet we know nothing about the players responsible for these events. The Arabidopsis thaliana Rhizobiale-like phosphatase 2 (AtRLPH2) is a novel protein phosphatase not found in mammals which, according to bioinformatics analysis, clusters with the serine/threonine-specific phospho-protein phosphatase (PPP) group. In the present work, it is shown that recombinant AtRLPH2 surprisingly behaves like a tyrosine phosphatase in vitro by dephosphorylating phospho-tyrosine peptides and having essentially no activity towards phospho-serine/threonine residues. Furthermore, the endogenous AtRLPH2 from Arabidopsis thaliana was also shown to preferentially dephosphorylate tyrosine phosphorylated peptides and protein. This work shows for the first time that a member of the plant PPP family of phosphatases has the capability to dedicate its activity solely toward phospho-tyrosine. In order to understand the novel substrate specificity of AtRLPH2 its crystal structure was elucidated, providing detailed mechanistic insight into its mode of function and characteristics of its potential substrates. AtRLPH2 possesses a basic pocket next to the active site which makes it imperative for the substrate to possess a phospho-threonine/serine two amino acids upstream the phospho-tyrosine. To gain a better understanding of AtRLPH2 significance and targets, a phosphoproteomics study was undertaken to compare phospho-tyrosine peptides from wild type and atrlph2 knockout plant lines. In summary, the atypical tyrosine phosphatase AtRLPH2 was characterized by a multidisciplinary approach involving biochemistry, cell biology, phosphoproteomics and structural biology.
- ItemOpen AccessRegulation of Myocardin Expression and Activity in Vascular Smooth Muscle Cells(2015-12-15) Singh, Pavneet; Zheng, Xi-Long; Walsh, Michael; Lees-Miller, SusanThe proliferation of vascular smooth muscle cells (VSMCs) plays a critical role in the development of various vascular diseases such as atherosclerosis. In order for SMCs to proliferate, it is widely believed that cells undergo a phenotypic conversion from a differentiated contractile phenotype to a dedifferentiated synthetic phenotype. The transcription co-activator myocardin is well established to play a role in SMC differentiation and proliferation. Therefore, it is crucial to understand how myocardin expression and activity are regulated in VSMCs. We investigated the regulation of myocardin expression and activity in SMCs at two different levels. (1) Myocardin undergoes ubiquitylation and degradation via UPS, which leads to an increase in its transcriptional activity. However, the E3 ligase responsible for myocardin ubiquitylation has not been identified. Atrogin‐1 is a muscle-specific E3 ligase which down‐regulates myocardin protein during skeletal muscle differentiation. Therefore, it is possible that atrogin‐1 causes ubiquitylation, which leads to proteasome mediated degradation of myocardin protein in VSMCs, thereby increasing myocardin activity. Our results showed that in VSMCs, atrogin‐1 directly interacted with myocardin in the nuclei and caused ubiquitylation and subsequent proteasome mediated degradation of myocardin. UPS-mediated myocardin degradation increased myocardin transcriptional activity through an increase in RNA polymerase II recruitment to myocardin target gene promoters. Moreover, atrogin‐1 expression increased the contractility of VSMCs in vitro and increased the contractile response of mouse aortas to potassium chloride (KCl) and phenylephrine (PE) ex vivo. Atrogin-1 expression also decreased VSMC proliferation in vitro. (2) The NF‐κB pathway is activated by various cytokines such as TNFα. Moreover, myocardin is known to inhibit VSMC proliferation by inhibiting the NF‐κB pathway. However, how the NF‐κB pathway activated by TNFα regulates myocardin remains unknown. We found that TNFα down‐regulated myocardin expression and activity in dedifferentiated cultured VSMCs by activating the NF‐κB pathway. TNFα-mediated myocardin downregulation decreased contractility and increased proliferation in cultured VSMCs. In addition, we found that in differentiated VSMCs, TNFα prevented myocardin mRNA degradation, which resulted in a further increase in myocardin expression and activity. TNFα-mediated myocardin mRNA stabilization resulted in increased contractility of VSMCs.
- ItemOpen AccessRegulation of Vascular Smooth Muscle Cell Motility by Protein Kinases: A Focus on Zipper-Interacting Protein Kinase(2017) Al-Ghabkari, Abdulhameed; MacDonald, Justin; Walsh, Michael; Moorhead, GregoryZipper-interacting protein kinase (ZIPK) is a protein serine/threonine kinase that mediates a variety of cellular functions. ZIPK is a key regulator of vascular smooth muscle (VSM) cell contractility and motility. Further investigations for the upstream regulators, activation signals, downstream target(s), regulatory mechanism(s) and the role of ZIPK in different signaling modules are required. Two major strategies were utilized in this study to examine ZIPK signaling in VSM cells; chemical genetics and application of small molecule inhibitors. For the chemical genetics strategy, ZIPK was engineered in the ATP-binding pocket by replacing a bulky amino acid (Leu) with a small one (Gly). This ZIPK-L93G kinase was introduced into VSM cells and then the NM-PPI inhibitor (selective for L93G-ZIPK, not for WT-ZIPK) was applied, which demonstrated an inhibitory effect on myosin phosphorylation. This strategy provides another approach to study ZIPK signaling, especially in the absence of specific inhibitors for ZIPK. Recent investigations led to the development of two small molecule inhibitors for ZIPK; DI and HS-38. The selectivity of the DI compound was assessed by; (i) in vitro studies; (ii) in situ analysis; and (iii) in silico molecular modelling. Our studies revealed that the DI compound was not selective for ZIPK; DI had effects on the cellular cytoskeleton and motility that were associated with diminution of ROCKII signaling pathways. The HS-38 compound was advantageous to delineate a novel signaling relationship between ZIPK and focal adhesion kinase (FAK). ZIPK inhibition by HS-38 or ZIPK knockdown with siRNA resulted in suppression of pY397-FAK phosphorylation and remodeling of the cytoskeletal architecture. Additional molecular details of this signaling mechanism implicate a member of the dual specificity phosphatase family (CDC14A) in a putative partnership with ZIPK to regulate focal adhesion dynamics and FAK phosphorylation.
- ItemOpen AccessThe Steroids In the Maintenance of remission of Proliferative Lupus nephritis (SIMPL) pilot trial(Canadian Journal of Kidney Health and Disease, 2014-11-28) Galbraith, Lauren; Manns, Braden; Hemmelgarn, Brenda; Walsh, MichaelBackground Patients with proliferative lupus nephritis are at risk of frequent relapses. Whether low- dose prednisone prevents relapses is uncertain. Objectives We undertook a pilot RCT to determine the feasibility of a larger trial. Design Pilot randomized controlled trial. Setting Single center Canadian outpatient nephrology clinic. Patients Participants with systemic lupus erythematosus (SLE) and a history of class III or IV lupus nephritis that achieved at least partial remission and remained on prednisone were eligible. Measurements Feasibility: proportion of eligible patients randomized and adherence to tapering regimen. Clinical: occurrence of renal or major non-renal flare of SLE. Methods We conducted a blinded, two-parallel-group randomized controlled trial of prednisone 7.5 mg/day (continuation) compared to a matching placebo (withdrawal). Results Of nineteen eligible patients screened, 15 (79%) were recruited and randomized; 8 to prednisone continuation and seven to withdrawal. All participants adhered to the tapering protocol to their assigned withdrawal or low-dose maintenance target. Over 36 months, the primary outcome occurred in four (50%) patients in the continuation group (three renal and one major non-renal flare), compared with one patient (14%) in the withdrawal group (one renal flare). Three participants (38%) in the continuation group had minor flares, while no patients in the withdrawal group did. Limitations This pilot RCT was small and not designed to assess the efficacy or safety of maintenance with low-dose prednisone. Conclusions The high proportion of eligible patients recruited, and success of protocol adherence suggest a large trial of prednisone maintenance therapy compared to withdrawal is feasible. Trial registration Current Controlled Trials ISRCTN31327267.
- ItemOpen AccessVascular Aging: from Smooth Muscle Cell Differentiation to Polyploidization(2016) Zhan, Shi; Zheng, Xi-Long; Xilong, Zheng; Carlos, Fernandes-Patron; Bonni, Shirin; Walsh, Michael; Riabowol, KarlAging is associated with various changes in the vascular system at different structural and functional levels. These changes include increased arterial wall thickness, luminal dilation and reduced compliance. As a major component of the vascular wall, vascular smooth muscle cells (VSMCs) play an important role in exhibiting proper vascular functions. VSMCs behaviors are significantly modified by vascular aging. In this thesis, we study VSMC phenotypic modulation and polyploidiation in vascular aging through three projects. (1) Vascular aging switches VSMC phenotype from a differentiated to a dedifferentiated phenotype, which is characteristic in atherosclerosis. As an important transcription co-activator, myocardin regulates the expression of SM-differentitation marker genes and acts as a critical regulator in VSMC phenotypic modulation in response to various factors. In this thesis, we showed that GSK-3β positively regulates the expression of SM-differentiation markers in VSMCs. We also found that GSK-3β phosphorylats and enhances myocardin transcriptional activity through increasing the recruitment of myocardin to the promoter of its target gene and positively regulates myocardin gene expression. In conclusion, these results suggest that GSK-3β promotes VSMC differentiation through the regulation of myocardin activity. (2) VSMCs polyploidization is a biomarker of vascular aging. VSMC polyploidization and apoptosis co-exist in the aged or hypertensive vascular wall, but whether polyploidization contributes to VSMC apoptosis remains unknown. In this thesis, we found that nocodazole (ND), a microtubule-interfering reagent, induces VSMC polyploidization and apoptosis in a temporal order. Inhibition of ND-induced VSMC polyploidization abolished further apoptosis, suggesting a causal relatioinship between VSMC polyploidization and apoptosis. Also, we identified that mTOR signaling is involved in ND-induced VSMC polyploidization. (3) Accumulative studies have pointed a potential role of mTOR signaling in aging. To further establish the role of mTOR in VSMCs polyploidiation in aging, we established a T-REx system to overexpress mTOR in VSMCs. Overexpression of mTOR activated mTORC1 signaling and further induced VSMC polyploidization and senescence. We also found that autophagy which is negatively regulated by mTORC1 signaling is not involved in mTOR-induced VSMC polyploidy, although autohphagy has been well-established in VSMC senescence. We conclude that mTORC1 signaling induces VSMC polyploidization and senescence through different downstream effecters.
- ItemOpen Access“You need a team”: perspectives on interdisciplinary symptom management using patient-reported outcome measures in hemodialysis care—a qualitative study(2023-01-20) Baragar, Brigitte; Schick-Makaroff, Kara; Manns, Braden; Love, Shannan; Donald, Maoliosa; Santana, Maria; Corradetti, Bonnie; Finlay, Juli; Johnson, Jeffrey A.; Walsh, Michael; Elliott, Meghan J.Abstract Background Patient-reported outcome measures (PROMs) are standardized instruments used for assessing patients’ perspectives on their health status at a point in time, including their health-related quality of life, symptoms, functionality, and physical, mental, and social wellbeing. For people with kidney failure receiving hemodialysis, addressing high symptom burden and complexity relies on care team members integrating their expertise to achieve common management goals. In the context of a program-wide initiative integrating PROMs into routine hemodialysis care, we aimed to explore patients’ and clinicians’ perspectives on the role of PROMs in supporting interdisciplinary symptom management. Methods We employed a qualitative descriptive approach using semi-structured interviews and observations. Eligible participants included adult patients receiving intermittent, outpatient hemodialysis for > 3 months, their informal caregivers, and hemodialysis clinicians (i.e., nurses, nephrologists, and allied health professionals) in Southern Alberta, Canada. Guided by thematic analysis, team members coded transcripts in duplicate and developed themes iteratively through review, refinement, and discussion. Results Thirty-three clinicians (22 nurses, 6 nephrologists, 5 allied health professionals), 20 patients, and one caregiver participated in this study. Clinicians described using PROMs to coordinate care across provider types using the resources available in their units, whereas patients tended to focus on the perceived impact of this concerted care on symptom trajectory and care experience. We identified 3 overarching themes with subthemes related to the role of PROMs in interdisciplinary symptom management in this setting: (1) Integrating care for interrelated symptoms (“You need a team”, conducive setting, role clarity and collaboration); (2) Streamlining information sharing and access (symptom data repository, common language for coordinated care); (3) Reshaping expectations (expectations for follow-up, managing symptom persistence). Conclusions We found that use of PROMs in routine hemodialysis care highlighted symptom interrelatedness and complexity and helped to streamline involvement of the interdisciplinary care team. Issues such as role flexibility and resource constraints may influence sustainability of routine PROM use in the outpatient hemodialysis setting.