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INTRODUCTION: Despite decades of research on risk-communication approaches, questions remain about the optimal methods for conveying risks for different outcomes across multiple time points, which can be necessary in applications such as discrete choice experiments (DCEs). We sought to compare the effects of 3 design factors: 1) separated versus integrated presentations of the risks for different outcomes, 2) use or omission of icon arrays, and 3) vertical versus horizontal orientation of the time dimension. METHODS: We conducted a randomized study among a demographically diverse sample of 2,242 US adults recruited from an online panel (mean age 59.8 y, s = 10.4 y; 21.9% African American) that compared risk-communication approaches that varied in the 3 factors noted above. The primary outcome was the number of correct responses to 12 multiple-choice questions asking survey respondents to identify specific numbers, contrast options to recognize dominance (larger v. smaller risks), and compute differences. We used linear regression to test the effects of the 3 design factors, controlling for health literacy, graph literacy, and numeracy. We also measured choice consistency in a subsequent DCE choice module. RESULTS: Mean comprehension varied significantly across versions (P < 0.001), with higher comprehension in the 3 versions that provided separated risk information for each risk. In the multivariable regression, separated risk presentation was associated with 0.58 more correct responses (P < 0.001; 95% confidence interval: 0.39, 0.77) compared with integrated risk information. Neither providing icon arrays nor using vertical versus horizontal time formats affected comprehension rates, although participant understanding did correlate with DCE choice consistency. CONCLUSIONS: In presentations of multiple risks over multiple time points, presenting risk information separately for each health outcome appears to increase understanding. HIGHLIGHTS: When conveying information about risks of different outcomes at multiple time points, separate presentations of single-outcome risks resulted in higher comprehension than presentations that combined risk information for different outcomes.We also observed benefits of presenting single-outcome risks separately among respondents with lower numeracy and graph literacy.Study participants who scored higher on risk understanding were more internally consistent in their responses to a discrete choice experiment.
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Comportamento de Escolha , Compreensão , Humanos , Pessoa de Meia-Idade , Feminino , Masculino , Idoso , Adulto , Medição de Risco/métodos , Comunicação , Letramento em Saúde/métodos , Letramento em Saúde/estatística & dados numéricos , Inquéritos e QuestionáriosAssuntos
Vigilância de Produtos Comercializados , United States Food and Drug Administration , Humanos , Estados Unidos , Vigilância de Produtos Comercializados/normas , Aprovação de Equipamentos , Procedimentos Endovasculares/instrumentação , Procedimentos Endovasculares/normas , Procedimentos Endovasculares/efeitos adversos , Dispositivos de Acesso Vascular/normas , Prótese VascularRESUMO
Registry Assessment of Peripheral Interventional Devices (RAPID) initiated the Pathways Program to provide a transparent, collaborative forum in which to pursue insights into multiple unresolved questions on benefit-risk of paclitaxel-coated devices, including understanding the basis of the mortality signal, without a demonstrable potential biological mechanism, and whether the late mortality signal could be artifact intrinsic to multiple independent prospective randomized data sources that did not prespecify death as a long-term end point. In response to the directive, the LEAN-Case Report Form working group focused on enhancements to the RAPID Phase I Minimum Core Data set through the addition of key clinical modifiers that would be more strongly linked to longer-term mortality outcomes after peripheral arterial disease intervention in the drug-eluting device era, with the goal to have future mortality signals more accurately examined.
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As medical device development becomes increasingly global, the opportunities and potential advantages offered by international clinical trial and regulatory approval strategies are also growing. In particular, medical device clinical trials involving sites in both the United States and Japan and intended to support marketing in both countries may warrant particular consideration, given the similarities in their regulatory systems, patients and clinical practice patterns, and market sizes. Since 2003, the US-Japan Harmonization By Doing (HBD) initiative has been focused on identifying and addressing clinical and regulatory barriers to medical devices access in both countries via collaboration between governmental, academic, and industry stakeholders. Through the efforts of HBD participants, US-Japanese clinical trials have been conducted and the resulting data have supported regulatory approval for marketing in both countries. Based on these experiences, this paper outlines some of the key factors to consider when developing a global clinical trial involving US and Japanese participation. These considerations include the mechanisms for consultation with regulatory authorities on clinical trial strategies, the regulatory framework for clinical trial notification and approval, recruitment and conduct of clinical sites, and lessons learned from specific US-Japanese clinical trial experiences. The goal of this paper is to promote global access to promising medical technologies by assisting potential clinical trial sponsors in understanding when an international strategy may be appropriate and successful.
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Aprovação de Equipamentos , Humanos , Estados Unidos , JapãoRESUMO
OBJECTIVE: This observational cohort study examined outcomes after peripheral vascular intervention (PVI) with paclitaxel coated devices (PCD) and non-PCD, and evaluated heterogeneity of treatment effect in populations of interest. METHODS: The study included patients undergoing percutaneous transluminal angioplasty and or stent placement between 1 October 2015 and 31 December 2018 in the Vascular Quality Initiative Registry linked to Medicare claims. It determined differences in patient mortality and ipsilateral major amputation after PVI with PCD and non-PCD using Kaplan-Meier analyses and Cox regressions with inverse probability weighting in three cohorts: (A) patients treated for femoropopliteal or infrapopliteal occlusive disease with or without any other concurrent treatment (n = 11 452); (B) those treated for isolated superficial femoral or popliteal artery disease (n = 5 519); and (C) patients with inclusion criteria designed to approximate RCT populations (n = 2 278). RESULTS: The mean age of patients was 72.3 (SD = 10.9) years, and 40.6% were female. In cohort A, patients receiving PCD had a lower mortality rate (HR 0.88, 95% CI 0.79 - 0.98) than those receiving non-PCD. There was no significant difference in mortality between groups in cohort B (HR 0.91, 95% CI 0.80 - 1.04) and cohort C (HR 1.10, 95% CI 0.84 - 1.43). Patients receiving PCD did not have a significantly elevated risk of major amputation compared with those receiving non-PCD (cohort A: HR 0.84, 95% CI 0.70 - 1.00; cohort B: HR 0.84, 95% CI 0.67 - 1.06; and cohort C: HR 1.05, 95% CI 0.51 - 2.14). CONCLUSION: No increased patient mortality or major amputation was found at three years after PVI with PCD vs. non-PCD in this large, linked registry claims study, after accounting for heterogeneity of treatment effect by population. The analysis and results from three cohorts intended to mirror the cohorts of previous studies provide robust and niche real world evidence on PCD safety and help to understand and reconcile previously discrepant findings.
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INTRODUCTION: The COVID-19 pandemic had an unprecedented impact on cardiovascular clinical research. The decision-making and state of study operations in cardiovascular trials 1-year after interruption has not been previously described. METHODS: In the spring of 2020, we created a pandemic impact task force to develop a landscape of use case scenarios from 17 device trials of peripheral artery disease (PAD) and coronary artery disease (CAD) interventions. In conjunction with publicly available (clinictrials.gov) study inclusion criteria, primary endpoints and study design, information was shared for this use-case landscape by trial leadership and data owners. RESULTS: A total of 17 actively enrolling trials (9 CAD and 8 PAD) volunteered to populate the use case landscape. All 17 were multicenter studies (12 in North America and 5 international). Fifteen studies were industry-sponsored, of which 13 were FDA approved IDEs, one was PCORI-sponsored and two were sponsored by the NIH. Enrollment targets ranged from 150 to 9000 pts. At the time of interruption, 5 trials were <20 % enrolled, 9 trials were 50-80 % enrolled and 3 trials were >80 % enrolled. At 1 year, the majority of studies were continuing to enroll in the context of more sporadic but ongoing pandemic activity. CONCLUSIONS: At 1 year from the first surge interruptions, most trials had resumed enrollment. Trials most heavily interrupted were trials early in enrollment and those trials not able to pivot to virtual patient and site visits. Further work is needed to determine the overall impact on vascular intervention trials disrupted during the COVID-19 pandemic.
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COVID-19 , Humanos , COVID-19/epidemiologia , Pandemias , Projetos de PesquisaRESUMO
Successful translation of new and innovative medical products from concept to clinical use is a complex endeavor that requires understanding and overcoming a variety of challenges. In particular, regulatory pathways and processes are often unfamiliar to academic researchers and start-ups, and even larger companies. Growing evidence suggests that the successful translation of ideas to products requires collaboration and cooperation between clinicians, researchers, industry, and regulators. A multi-stakeholder group developed this review to enhance regulatory knowledge and thereby improve translational success for medical devices. Communication between and among stakeholders is identified as a critical factor. Current regulatory programs and processes to facilitate communication and translation of innovative devices are described and discussed. Case studies are used to highlight the importance of flexibility when considering evidence requirements. We provide a review of emerging strategies, opportunities, and best practices to increase the regulatory knowledge base and facilitate medical device translation by all stakeholders. Clinicians, regulators, industry, and researchers require regulatory knowledge and collaboration for successful translation of innovative medical devices.
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ComunicaçãoRESUMO
Regulatory approval processes for medical devices in Japan and the United States of America (US) often require similar clinical trials to establish safety and effectiveness. The Harmonization by Doing (HBD) program provides a collaborative environment for communication between regulators, academics and industry, facilitating the design and conduct of US/Japanese clinical trials supporting approval in both countries.
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Aterectomia Coronária , Doença da Artéria Coronariana , Intervenção Coronária Percutânea , Calcificação Vascular , Aterectomia , Aterectomia Coronária/efeitos adversos , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/cirurgia , Humanos , Japão , Intervenção Coronária Percutânea/efeitos adversos , Resultado do Tratamento , Estados Unidos , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/terapiaRESUMO
OBJECTIVES: This study sought to determine the safety and efficacy of paclitaxel (PTX) devices in the treatment of peripheral artery disease involving the femoropopliteal artery. BACKGROUND: A meta-analysis of PTX devices for the treatment of femoropopliteal artery disease reported a mortality signal. METHODS: This was a multicenter cohort study using an integrated clinical data surveillance system to conduct a prospective, propensity score-matched survival analysis of 2,456 patients in the Society for Vascular Surgery Vascular Quality Initiative from January 2017 to May 2020. The study compared PTX drug-coated balloon angioplasty versus percutaneous transluminal balloon angioplasty, PTX drug-eluting stents versus bare-metal stents, and any PTX device versus any non-PTX device. The primary outcome was 2-year survival. Secondary endpoints were successful ambulation and interventional success. RESULTS: Treatment with any PTX device versus any non-PTX device was associated with increased 2-year survival (89.5% vs 86.7%; HR: 0.79; 95% CI: 0.72-0.87; P = 0.004), improved interventional success (81.6% vs 77.6%; HR: 0.82; 95% CI: 0.74-0.91; P < 0.001), and higher rates of independent ambulation at 1 year (86.0% vs 83.4%; HR: 0.85; 95% CI: 0.79-0.91; P = 0.008). Treatment with PTX drug-coated balloon angioplasty was associated with improved survival at 2 years (88.9% vs 85.7%; HR: 0.77; 95% CI: 0.70-0.86; P = 0.005), while PTX drug-eluting stent therapy was associated with similar survival compared with bare-metal stent therapy (91.3% vs 89.6%; HR: 0.84; 95% CI: 0.70-1.01; P = 0.36). CONCLUSIONS: In this prospective, active surveillance of a national clinical registry, PTX-containing devices were associated with increased survival at 2 years and improved clinical outcomes at 1 year. (VQI DELTA Paclitaxel Device Safety Analysis [VQI-PTX]; NCT04110288).
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Angioplastia com Balão , Fármacos Cardiovasculares , Stents Farmacológicos , Doença Arterial Periférica , Estudos de Coortes , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/cirurgia , Humanos , Estudos Multicêntricos como Assunto , Paclitaxel , Doença Arterial Periférica/tratamento farmacológico , Doença Arterial Periférica/terapia , Artéria Poplítea/diagnóstico por imagem , Artéria Poplítea/cirurgia , Estudos Prospectivos , Resultado do Tratamento , Grau de Desobstrução VascularAssuntos
Angioplastia com Balão , Paclitaxel/administração & dosagem , Doença Arterial Periférica/terapia , Stents , Angioplastia com Balão/efeitos adversos , Angioplastia com Balão/instrumentação , Aterosclerose/terapia , Materiais Revestidos Biocompatíveis/efeitos adversos , Humanos , Paclitaxel/efeitos adversosRESUMO
The Registry Assessment of Peripheral Devices (RAPID) convened a multidisciplinary group of stakeholders including clinicians, academicians, regulators and industry representatives to conduct an in-depth review of limitations associated with the data available to assess the paclitaxel mortality signal. Available studies were evaluated to identify strengths and limitations in the study design and data quality, which were translated to lessons learned to help guide the design, execution, and analyses of future studies. We suggest numerous actionable responses, such as the development and use of harmonized data points and outcomes in a consensus lean case report form. We advocate for reduction in missing data and efficient means for accrual of larger sample sizes in Peripheral arterial disease studies or use of supplemental datasets. Efforts to share lessons learned and working collaboratively to address such issues may improve future data in this device area and ultimately benefit patients. Condensed Abstract: Data sources evaluating paclitaxel-coated devices were evaluated to identify strengths and limitations in the study design and data quality, which were translated to lessons learned to help guide the design, execution, and analyses of future studies. We suggest numerous actionable responses, which we believe may improve future data in this device area and ultimately benefit patients.
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Angioplastia , Stents Farmacológicos , Mortalidade , Paclitaxel/administração & dosagem , Doença Arterial Periférica/cirurgia , Moduladores de Tubulina/administração & dosagem , Comitês Consultivos , Angioplastia com Balão , Aterectomia , Elementos de Dados Comuns , Confiabilidade dos Dados , Coleta de Dados , Artéria Femoral/cirurgia , Humanos , Metanálise como Assunto , Artéria Poplítea , Ensaios Clínicos Controlados Aleatórios como Assunto , Reprodutibilidade dos Testes , Medição de Risco , StentsRESUMO
BACKGROUND: The Superficial Femoral Artery-Popliteal EvidencE Development Study Group developed contemporary objective performance goals (OPGs) for peripheral vascular interventions (PVI) for superficial femoral artery (SFA)-popliteal artery disease using the Registry Assessment of Peripheral Interventional Devices. METHODS: The Society for Vascular Surgery Vascular Quality Initiative PVI registry from January 2010 to October 2016 was used to develop OPGs based on SFA-popliteal procedures (n = 21,377) for intermittent claudication and critical limb ischemia (CLI). OPGs included 1-year rates for target lesion revascularization (TLR), major amputation, and 1 and 4-year survival rates. OPGs were calculated for the SFA and popliteal arteries and stratified by four treatments: angioplasty alone (percutaneous transluminal angioplasty [PTA]), self-expanding stenting, atherectomy, and any treatment type. Outcomes were illustrated by unadjusted Kaplan-Meier analyses. RESULTS: Cohorts included PTA (n = 7505), stenting (n = 9217), atherectomy (n = 2510) and any treatment (n = 21,377). The mean age was 69 years, 58% were male, 79% were White, and 52% had CLI. The freedom from TLR OPGs at 1 year in the SFA were 80.3% (PTA), 83.2% (stenting), 83.9% (atherectomy), and 81.9% (any treatments). The freedom from TLR OPGs at 1 year in the popliteal were 81.3% (PTA), 81.3% (stenting), 80.2% (atherectomy), and 81.1% (any treatments). The freedom from major amputation OPGs at 1 year after SFA PVI were 93.4% (PTA), 95.7% (stenting), 95.1% (atherectomy), and 94.8% (any treatments). The freedom from major amputation OPG at 1 year after popliteal PVI were 90.5% (PTA), 93.7% (stenting), 91.8% (atherectomy), and 91.8%, (any treatments). The 4-year survival OPGs after SFA PVI were 76% (PTA), 80% (stenting), 82% (atherectomy), and 79% (any treatments), and for the popliteal artery were 72% (PTA), 77% (stenting), 82% (atherectomy), and 75% (any treatment). On a multivariable analysis, which included patient-level, leg-level, and lesion-level covariates, CLI was the single independent factor associated with increased TLR, amputation, and mortality. CONCLUSIONS: The Superficial Femoral Artery-Popliteal EvidencE Development OPGs define a new, contemporary benchmark for SFA-popliteal interventions using a large subset of real-world evidence to inform more efficient peripheral device clinical trial designs to support regulatory and clinical decision-making. It is appropriate to discuss proposals intended for regulatory approval with the US Food and Drug Administration to refine the OPG to match the specific trial population. The OPGs may be updated using coordinated registry networks to assess long-term real-world device performance.
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Benchmarking , Procedimentos Endovasculares/instrumentação , Artéria Femoral , Claudicação Intermitente/terapia , Isquemia/terapia , Doença Arterial Periférica/terapia , Artéria Poplítea , Indicadores de Qualidade em Assistência à Saúde , Idoso , Idoso de 80 Anos ou mais , Amputação Cirúrgica , Benchmarking/normas , Estado Terminal , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/mortalidade , Procedimentos Endovasculares/normas , Feminino , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/fisiopatologia , Mortalidade Hospitalar , Humanos , Claudicação Intermitente/diagnóstico por imagem , Claudicação Intermitente/mortalidade , Claudicação Intermitente/fisiopatologia , Isquemia/diagnóstico por imagem , Isquemia/mortalidade , Isquemia/fisiopatologia , Salvamento de Membro , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/diagnóstico por imagem , Doença Arterial Periférica/mortalidade , Doença Arterial Periférica/fisiopatologia , Artéria Poplítea/diagnóstico por imagem , Artéria Poplítea/fisiopatologia , Indicadores de Qualidade em Assistência à Saúde/normas , Sistema de Registros , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Estados UnidosRESUMO
The Vascular Implant Surveillance and Interventional Outcomes Network (VISION) is a Coordinated Registry Network (CRN) a member of Medical Device Epidemiology Network, a U.S. Food and Drug Administration (FDA)-supported global public-private partnership that seeks to advance the collection and use of real-world data to improve patient outcomes. The VISION CRN began in September 2015 and held its first strategic meeting on September 10, 2018, at the FDA headquarters in Silver Spring, Maryland. VISION is a collaboration of the Vascular Quality Initiative (VQI), the FDA, and other stakeholders. At this annual meeting, leaders from the FDA, VQI, industry representatives, population health researchers, and regulatory science experts gathered to discuss strategic goals and opportunities for VISION. One of the key focus areas for VISION is linkage of VQI registry data to Medicare, longitudinal data sources maintained by various states, and other relevant data sources, as a model for efficient, cost-saving, and effectual evidence generation and appraisal. This would provide the means to expand data collection, assess long-term procedural outcomes across the carotid, lower extremity, aortic, and venous intervention datasets, and execute registry-based trials through the CRN structure in an efficient, cost-effective manner. Looking forward, VISION strives to validate long-term outcome data in the VQI using industry datasets, in hopes of using CRNs to make device regulatory decisions. With the guidance of a steering committee, VISION will provide vascular surgeons, industry, and regulators the appropriate data to improve care for patients with vascular disease.
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Procedimentos Endovasculares/instrumentação , Equipamentos e Provisões , Vigilância de Produtos Comercializados , Parcerias Público-Privadas , United States Food and Drug Administration , Procedimentos Cirúrgicos Vasculares/instrumentação , Procedimentos Endovasculares/efeitos adversos , Desenho de Equipamento , Medicina Baseada em Evidências , Humanos , Cooperação Internacional , Segurança do Paciente , Vigilância da População , Sistema de Registros , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Estados Unidos , Procedimentos Cirúrgicos Vasculares/efeitos adversosRESUMO
OBJECTIVE: The current state of evaluating patients with peripheral artery disease and more specifically of evaluating medical devices used for peripheral vascular intervention (PVI) remains challenging because of the heterogeneity of the disease process, the multiple physician specialties that perform PVI, the multitude of devices available to treat peripheral artery disease, and the lack of consensus about the best treatment approaches. Because PVI core data elements are not standardized across clinical care, clinical trials, and registries, aggregation of data across different data sources and physician specialties is currently not feasible. METHODS: Under the auspices of the U.S. Food and Drug Administration's Medical Device Epidemiology Network initiative-and its PASSION (Predictable and Sustainable Implementation of the National Registries) program, in conjunction with other efforts to align clinical data standards-the Registry Assessment of Peripheral Interventional Devices (RAPID) workgroup was convened. RAPID is a collaborative, multidisciplinary effort to develop a consensus lexicon and to promote interoperability across clinical care, clinical trials, and national and international registries of PVI. RESULTS: The current manuscript presents the initial work from RAPID to standardize clinical data elements and definitions, to establish a framework within electronic health records and health information technology procedural reporting systems, and to implement an informatics-based approach to promote the conduct of pragmatic clinical trials and registry efforts in PVI. CONCLUSIONS: Ultimately, we hope this work will facilitate and improve device evaluation and surveillance for patients, clinicians, health outcomes researchers, industry, policymakers, and regulators.
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Prótese Vascular , Aprovação de Equipamentos/normas , Procedimentos Endovasculares/instrumentação , Doença Arterial Periférica/terapia , Sistema de Registros/normas , Stents , United States Food and Drug Administration/normas , Procedimentos Cirúrgicos Vasculares/instrumentação , Mineração de Dados/normas , Registros Eletrônicos de Saúde/normas , Procedimentos Endovasculares/efeitos adversos , Humanos , Cooperação Internacional , Informática Médica/normas , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/fisiopatologia , Vigilância de Produtos Comercializados/normas , Desenho de Prótese , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Estados Unidos/epidemiologia , Procedimentos Cirúrgicos Vasculares/efeitos adversos , Fluxo de TrabalhoRESUMO
BACKGROUND: The current state of evaluating patients with peripheral artery disease and more specifically of evaluating medical devices used for peripheral vascular intervention (PVI) remains challenging because of the heterogeneity of the disease process, the multiple physician specialties that perform PVI, the multitude of devices available to treat peripheral artery disease, and the lack of consensus about the best treatment approaches. Because PVI core data elements are not standardized across clinical care, clinical trials, and registries, aggregation of data across different data sources and physician specialties is currently not feasible.MethodsâandâResults:Under the auspices of the U.S. Food and Drug Administration's Medical Device Epidemiology Network initiative-and its PASSION (Predictable and Sustainable Implementation of the National Registries) program, in conjunction with other efforts to align clinical data standards-the Registry Assessment of Peripheral Interventional Devices (RAPID) workgroup was convened. RAPID is a collaborative, multidisciplinary effort to develop a consensus lexicon and to promote interoperability across clinical care, clinical trials, and national and international registries of PVI. The current manuscript presents the initial work from RAPID to standardize clinical data elements and definitions, to establish a framework within electronic health records and health information technology procedural reporting systems, and to implement an informatics-based approach to promote the conduct of pragmatic clinical trials and registry efforts in PVI. CONCLUSIONS: Ultimately, we hope this work will facilitate and improve device evaluation and surveillance for patients, clinicians, health outcomes researchers, industry, policymakers, and regulators.
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Equipamentos e Provisões/normas , Doença Arterial Periférica , Sistema de Registros/normas , Monitoramento Epidemiológico , Humanos , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/terapia , Padrões de ReferênciaRESUMO
CNS damage often results in demyelination of spared axons due to oligodendroglial cell death and dysfunction near the injury site. Although new oligodendroglia are generated following CNS injury and disease, the process of remyelination is typically incomplete resulting in long-term functional deficits. Chondroitin sulfate proteoglycans (CSPGs) are upregulated in CNS grey and white matter following injury and disease and are a major component of the inhibitory scar that suppresses axon regeneration. CSPG inhibition of axonal regeneration is mediated, at least in part, by the protein tyrosine phosphatase sigma (PTPσ) receptor. Recent evidence demonstrates that CSPGs inhibit OL process outgrowth, however, the means by which their effects are mediated remains unclear. Here we investigate the role of PTPσ in CSPG inhibition of OL function. We found that the CSPGs, aggrecan, neurocan and NG2 all imposed an inhibitory effect on OL process outgrowth and myelination. These inhibitory effects were reversed by degradation of CSPGs with Chondroitinase ABC prior to OL exposure. RNAi-mediated down-regulation of PTPσ reversed the inhibitory effect of CSPGs on OL process outgrowth and myelination. Likewise, CSPG inhibition of process outgrowth and myelination was significantly reduced in cultures containing PTPσ(-/-) OLs. Finally, inhibition of Rho-associated kinase (ROCK) increased OL process outgrowth and myelination during exposure to CSPGs. These results suggest that in addition to their inhibitory effects on axon regeneration, CSPGs have multiple inhibitory actions on OLs that result in incomplete remyelination following CNS injury. The identification of PTPσ as a receptor for CSPGs, and the participation of ROCK downstream of CSPG exposure, reveal potential therapeutic targets to enhance white matter repair in the damaged CNS.
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Proteoglicanas de Sulfatos de Condroitina/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Bainha de Mielina/efeitos dos fármacos , Oligodendroglia/efeitos dos fármacos , Proteínas Tirosina Fosfatases Classe 2 Semelhantes a Receptores/metabolismo , Agrecanas/farmacologia , Animais , Animais Recém-Nascidos , Antígenos/farmacologia , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Condroitina ABC Liase/farmacologia , Gânglios Espinais/citologia , Gangliosídeos/metabolismo , Proteína Básica da Mielina/metabolismo , Proteínas de Neurofilamentos/metabolismo , Proteoglicanas/farmacologia , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Células-Tronco , Quinases Associadas a rho/metabolismoRESUMO
Neuronal activity promotes myelination in vivo and in vitro. However, the molecular events that mediate activity-dependent myelination are not completely understood. Seven, daily 1 h sessions of patterned electrical stimulation (ESTIM) promoted myelin segment formation in mixed cultures of dorsal root ganglion (DRG) neurons and oligodendrocytes (OLs); the increase in myelination was frequency-dependent. Myelin segment formation was also enhanced following exposure of DRGs to ESTIM prior to OL addition, suggesting that ESTIM promotes myelination in a manner involving neuron-specific signaling. Cyclic adenosine monophosphate (cAMP) levels in DRGs were increased three-fold following ESTIM, and artificially increasing cAMP mimicked the ability of ESTIM to promote myelination. Alternatively, inhibiting the cAMP pathway suppressed ESTIM-induced myelination. We used compartmentalized, microfluidic platforms to isolate DRG soma from OLs and assessed cell-type specific effects of ESTIM on myelination. A selective increase or decrease in DRG cAMP levels resulted in enhanced or suppressed myelination, respectively. This work describes a novel role for the cAMP pathway in neurons that results in enhanced myelination.
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Potenciais de Ação/fisiologia , AMP Cíclico/metabolismo , Bainha de Mielina/metabolismo , Neurônios/fisiologia , Oligodendroglia/metabolismo , Transdução de Sinais/fisiologia , Animais , Axônios/metabolismo , Células Cultivadas , Estimulação Elétrica , Gânglios Espinais/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
Axon demyelination contributes to the loss of sensory and motor function following injury or disease in the central nervous system. Numerous reports have demonstrated that myelination can be achieved in neuron/oligodendrocyte co-cultures. However, the ability to selectively treat neuron or oligodendrocyte (OL) cell bodies in co-cultures improves the value of these systems when designing mechanism-based therapeutics. We have developed a microfluidic-based compartmentalized culture system to achieve segregation of neuron and OL cell bodies while simultaneously allowing the formation of myelin sheaths. Our microfluidic platform allows for a high replicate number, minimal leakage, and high flexibility. Using a custom built lid, fit with platinum electrodes for electrical stimulation (10-Hz pulses at a constant 3 V with ~190 kΩ impedance), we employed the microfluidic platform to achieve activity-dependent myelin segment formation. Electrical stimulation of dorsal root ganglia resulted in a fivefold increase in the number of myelinated segments/mm² when compared to unstimulated controls (19.6 ± 3.0 vs. 3.6 ± 2.3 MBP+ segments/mm²). This work describes the modification of a microfluidic, multi-chamber system so that electrical stimulation can be used to achieve increased levels of myelination while maintaining control of the cell culture microenvironment.
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Axônios/metabolismo , Técnicas de Cultura de Células/instrumentação , Técnicas Analíticas Microfluídicas/instrumentação , Bainha de Mielina/metabolismo , Animais , Axônios/ultraestrutura , Técnicas de Cocultura/instrumentação , Estimulação Elétrica , Gânglios Espinais/metabolismo , Oligodendroglia/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Oligodendrocyte (OLG) death plays a major role in white matter dysfunction and demyelination following injury to the CNS. Axonal contact, communication, and neuronal activity appear to promote OLG survival and function in cell culture and during development. The application of electrical stimulation to mixed neural cultures has been shown to promote OLG differentiation and the formation of myelin in vitro. Here we show that OLG viability can be significantly enhanced in mixed cortical cultures by applying biphasic pulses of electrical stimulation (ESTIM). Enhanced survival via ESTIM requires the presence of neurons and is suppressed by inhibition of voltage-gated sodium channels. Additionally, contact between the axon and OLG is necessary for ESTIM to promote OLG survival. This report suggests that patterned neuronal activity could repress delayed progression of white matter injury and promote CNS repair in neurological conditions that involve white matter damage.