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Jacobson PB, Mothe A, Levy A, Krakovsky M, Hooker BA, Zhang X, Mollon J, Mordashova Y, Droescher M, Weiss S, Barghorn S, Dreher I, Awwad K, Nimmrich V, Huang L, Fung E, Buck WR, Pfleeger K, Ziemann A, Smith E, Fox GB, Tator CH, Gold M. Neutralizing RGMa with Elezanumab Promotes Cerebroprotection and Recovery in Rabbit Middle Cerebral Artery Occlusion. Transl Stroke Res 2023:10.1007/s12975-023-01164-2. [PMID: 37326791 DOI: 10.1007/s12975-023-01164-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/23/2023] [Accepted: 05/26/2023] [Indexed: 06/17/2023]
Abstract
Repulsive guidance molecule A (RGMa) is an inhibitor of neuronal growth and survival which is upregulated in the damaged central nervous system following acute spinal cord injury (SCI), traumatic brain injury, acute ischemic stroke (AIS), and other neuropathological conditions. Neutralization of RGMa is neuroprotective and promotes neuroplasticity in several preclinical models of neurodegeneration and injury including multiple sclerosis, AIS, and SCI. Given the limitations of current treatments for AIS due to narrow time windows to intervention (TTI), and restrictive patient selection criteria, there is significant unmet need for therapeutic agents that enable tissue survival and repair following acute ischemic damage for a broader population of stroke patients. In this preclinical study, we evaluated whether elezanumab, a human anti-RGMa monoclonal antibody, could improve neuromotor function and modulate neuroinflammatory cell activation following AIS with delayed intervention times up to 24 h using a rabbit embolic permanent middle cerebral artery occlusion model (pMCAO). In two replicate 28-day pMCAO studies, weekly intravenous infusions of elezanumab, over a range of doses and TTIs of 6 and 24 h after stroke, significantly improved neuromotor function in both pMCAO studies when first administered 6 h after stroke. All elezanumab treatment groups, including the 24 h TTI group, had significantly less neuroinflammation as assessed by microglial and astrocyte activation. The novel mechanism of action and potential for expanding TTI in human AIS make elezanumab distinct from current acute reperfusion therapies, and support evaluation in clinical trials of acute CNS damage to determine optimal dose and TTI in humans. A: Ramified/resting astrocytes and microglia in a normal, uninjured rabbit brain. B: Rabbit pMCAO brain illustrating lesion on right side of brain (red), surrounded by penumbra (pink) during acute phase post stroke, with minimal injury to left brain hemisphere. Penumbra characterized by activated astrocytes and microglia (region in crosshair within circle), with upregulation of free and bound RGMa. C: Elezanumab binds to both free and bound RGMa, preventing full activation of astrocytes and microglia. D: Elezanumab is efficacious in rabbit pMCAO with a 4 × larger TTI window vs. tPA (6 vs. 1.5 h, respectively). In human AIS, tPA is approved for a TTI of 3-4.5 h. Elezanumab is currently being evaluated in a clinical Ph2 study of AIS to determine the optimal dose and TTI (NCT04309474).
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Affiliation(s)
- Peer B Jacobson
- Department of Translational Sciences, Imaging Research, AbbVie Inc., 1 North Waukegan Rd, North Chicago, IL, 60064, USA.
| | - Andrea Mothe
- Division of Experimental and Translational Neuroscience, Krembil Brain Institute & University Health Network, Toronto, ON, M5T 0S8, Canada
| | | | | | - Bradley A Hooker
- Department of Translational Sciences, Imaging Research, AbbVie Inc., 1 North Waukegan Rd, North Chicago, IL, 60064, USA
| | - Xiaomeng Zhang
- Department of Translational Sciences, Imaging Research, AbbVie Inc., 1 North Waukegan Rd, North Chicago, IL, 60064, USA
| | - Jennifer Mollon
- Data and Statistical Sciences, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, 67061, KnollstrasseLudwigshafen, Germany
| | - Yulia Mordashova
- Data and Statistical Sciences, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, 67061, KnollstrasseLudwigshafen, Germany
| | - Mathias Droescher
- Discovery Biology, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Sabine Weiss
- Discovery Biology, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Stefan Barghorn
- Discovery Biology, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Ingeborg Dreher
- Department of Drug Metabolism, Pharmacokinetics and Bioanalysis, AbbVie Deutschland GmbH & Co. KG, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Khader Awwad
- Department of Drug Metabolism, Pharmacokinetics and Bioanalysis, AbbVie Deutschland GmbH & Co. KG, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Volker Nimmrich
- Department of Drug Metabolism, Pharmacokinetics and Bioanalysis, AbbVie Deutschland GmbH & Co. KG, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Lili Huang
- AbbVie Biologics, AbbVie Bioresearch Center, 100 Research Drive, Worcester, MA, 01605, USA
| | - Emma Fung
- AbbVie Biologics, AbbVie Bioresearch Center, 100 Research Drive, Worcester, MA, 01605, USA
| | - Wayne R Buck
- Preclinical Safety, AbbVie Inc, 1 North Waukegan Rd, North Chicago, IL, 60064, USA
| | - Kimberly Pfleeger
- Department of Neuroscience Development, AbbVie Inc, 1 North Waukegan Rd, North Chicago, IL, 60064, USA
| | - Adam Ziemann
- Department of Neuroscience Development, AbbVie Inc, 1 North Waukegan Rd, North Chicago, IL, 60064, USA
| | - Elaine Smith
- Department of Neuroscience Development, AbbVie Inc, 1 North Waukegan Rd, North Chicago, IL, 60064, USA
| | - Gerard B Fox
- Department of Translational Sciences, Imaging Research, AbbVie Inc., 1 North Waukegan Rd, North Chicago, IL, 60064, USA
| | - Charles H Tator
- Division of Experimental and Translational Neuroscience, Krembil Brain Institute & University Health Network, Toronto, ON, M5T 0S8, Canada
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON, M5T 2S8, Canada
| | - Michael Gold
- Department of Neuroscience Development, AbbVie Inc, 1 North Waukegan Rd, North Chicago, IL, 60064, USA
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2
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Smith E, Dreher I, Droescher M, Hooker BA, Mollon J, Zhang X, Jacobson PB. Abstract TMP110: Elezanumab Decreases Neuronal Damage And Improves Functional Recovery In A Rabbit Model Of Permanent Middle Cerebral Artery Occlusion. Stroke 2023. [DOI: 10.1161/str.54.suppl_1.tmp110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Introduction:
Current acute interventions for ischemic stroke aim to restore perfusion of affected tissue. There is an unmet need for therapies that protect neurons from ischemic damage and/or enhance natural repair processes to restore function. In humans, the neuronal growth and survival inhibitor RGMa (repulsive guidance molecule A) is upregulated following ischemic stroke. Elezanumab is a novel, humanized monoclonal antibody targeting RGMa. Preclinical evidence in traumatic and ischemic models of CNS damage suggest a protective and regenerative mechanisms for elezanumab following CNS damage.
Methods:
Elezanumab was evaluated in a rabbit permanent middle cerebral artery occlusion (MCAO) model of acute ischemic stroke by injection of an autologous blood clot. In replicate experiments, elezanumab (1, 10 and 40 mg/kg) or IgG control was administered 6 hours post occlusion or 24 hours post occlusion (10 mg/kg). Animals were dosed weekly through 28 days. Functional ability was assessed using the Neuromotor Score, a composite of sensorimotor performance tasks. Ex vivo MRI, histology, and fluid biomarker analyses were performed.
Results:
MCAO consistently reduced cerebral blood flow by ~60% and resulted in neuromotor dysfunction. All doses of elezanumab demonstrated statistically significantly improved neuromotor function and recovery rate versus controls when dosed 6 hours post occlusion. The 10 mg/kg group dosed 24 hours post occlusion did not show a statistically significant functional improvement versus controls. Infarct volumes, plasma neurofilament light chain levels, and histological evidence of microglial proliferation were all significantly reduced with elezanumab treatment versus controls, including in the delayed elezanumab treatment group.
Conclusions:
Elezanumab treatment was associated with improved functional recovery and reduced markers of neuronal damage. Collectively, these data support a neuroprotective role for elezanumab in this translational model of acute ischemic stroke. Elezanumab is now being tested in a Phase 2a clinical trial for acute ischemic stroke.
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Russo MJ, Orru CD, Concha-Marambio L, Giaisi S, Groveman BR, Farris CM, Holguin B, Hughson AG, LaFontant DE, Caspell-Garcia C, Cofey CS, Mollon J, Hutten SJ, Merchant K, Heym RG, Soto C, Caughey B, Kang UJ. Correction to: High diagnostic performance of independent alpha-synuclein seed amplification assays for detection of early Parkinson's disease. Acta Neuropathol Commun 2021; 9:190. [PMID: 34836545 PMCID: PMC8620217 DOI: 10.1186/s40478-021-01292-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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4
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Russo MJ, Orru CD, Concha-Marambio L, Giaisi S, Groveman BR, Farris CM, Holguin B, Hughson AG, LaFontant DE, Caspell-Garcia C, Coffey CS, Mollon J, Hutten SJ, Merchant K, Heym RG, Soto C, Caughey B, Kang UJ. High diagnostic performance of independent alpha-synuclein seed amplification assays for detection of early Parkinson's disease. Acta Neuropathol Commun 2021; 9:179. [PMID: 34742348 PMCID: PMC8572469 DOI: 10.1186/s40478-021-01282-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/22/2021] [Indexed: 01/14/2023] Open
Abstract
Alpha-synuclein seed amplification assays (αSyn-SAAs) are promising diagnostic tools for Parkinson's disease (PD) and related synucleinopathies. They enable detection of seeding-competent alpha-synuclein aggregates in living patients and have shown high diagnostic accuracy in several PD and other synucleinopathy patient cohorts. However, there has been confusion about αSyn-SAAs for their methodology, nomenclature, and relative accuracies when performed by various laboratories. We compared αSyn-SAA results obtained from three independent laboratories to evaluate reproducibility across methodological variations. We utilized the Parkinson's Progression Markers Initiative (PPMI) cohort, with DATSCAN data available for comparison, since clinical diagnosis of early de novo PD is critical for neuroprotective trials, which often use dopamine transporter imaging to enrich their cohorts. Blinded cerebrospinal fluid (CSF) samples for a randomly selected subset of PPMI subjects (30 PD, 30 HC, and 20 SWEDD), from both baseline and year 3 collections for the PD and HC groups (140 total CSF samples) were analyzed in parallel by each lab according to their own established and optimized αSyn-SAA protocols. The αSyn-SAA results were remarkably similar across laboratories, displaying high diagnostic performance (sensitivity ranging from 86 to 96% and specificity from 93 to 100%). The assays were also concordant for samples with results that differed from clinical diagnosis, including 2 PD patients determined to be clinically inconsistent with PD at later time points. All three assays also detected 2 SWEDD subjects as αSyn-SAA positive who later developed PD with abnormal DAT-SPECT. These multi-laboratory results confirm the reproducibility and value of αSyn-SAA as diagnostic tools, illustrate reproducibility of the assay in expert hands, and suggest that αSyn-SAA has potential to provide earlier diagnosis with comparable or superior accuracy to existing methods.
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Affiliation(s)
- Marco J. Russo
- grid.137628.90000 0004 1936 8753The Marlene and Paolo Fresco Institute for Parkinson’s & Movement Disorders, Department of Neurology, Department of Neuroscience and Physiology, Neuroscience Institute, The Parekh Center for Interdisciplinary Neurology, NYU Grossman School of Medicine, New York, NY USA
| | - Christina D. Orru
- grid.419681.30000 0001 2164 9667Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT USA
| | | | - Simone Giaisi
- grid.467162.00000 0004 4662 2788AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany
| | - Bradley R. Groveman
- grid.419681.30000 0001 2164 9667Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT USA
| | | | - Bret Holguin
- grid.504117.6R&D Unit, Amprion Inc., San Diego, CA USA
| | - Andrew G. Hughson
- grid.419681.30000 0001 2164 9667Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT USA
| | - David-Erick LaFontant
- grid.214572.70000 0004 1936 8294Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA USA
| | - Chelsea Caspell-Garcia
- grid.214572.70000 0004 1936 8294Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA USA
| | - Christopher S. Coffey
- grid.214572.70000 0004 1936 8294Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA USA
| | - Jennifer Mollon
- grid.467162.00000 0004 4662 2788AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany
| | - Samantha J. Hutten
- grid.430781.90000 0004 5907 0388Michael J. Fox Foundation for Parkinson’s Research, New York, NY USA
| | - Kalpana Merchant
- grid.16753.360000 0001 2299 3507Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Roland G. Heym
- grid.467162.00000 0004 4662 2788AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany
| | - Claudio Soto
- grid.504117.6R&D Unit, Amprion Inc., San Diego, CA USA ,grid.267308.80000 0000 9206 2401Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX USA
| | - Byron Caughey
- grid.419681.30000 0001 2164 9667Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT USA
| | - Un Jung Kang
- grid.137628.90000 0004 1936 8753The Marlene and Paolo Fresco Institute for Parkinson’s & Movement Disorders, Department of Neurology, Department of Neuroscience and Physiology, Neuroscience Institute, The Parekh Center for Interdisciplinary Neurology, NYU Grossman School of Medicine, New York, NY USA
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5
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Jacobson PB, Goody R, Lawrence M, Mueller BK, Zhang X, Hooker BA, Pfleeger K, Ziemann A, Locke C, Barraud Q, Droescher M, Bernhard J, Popp A, Boeser P, Huang L, Mollon J, Mordashova Y, Cui YF, Savaryn JP, Grinnell C, Dreher I, Gold M, Courtine G, Mothe A, Tator CH, Guest JD. Elezanumab, a human anti-RGMa monoclonal antibody, promotes neuroprotection, neuroplasticity, and neurorecovery following a thoracic hemicompression spinal cord injury in non-human primates. Neurobiol Dis 2021; 155:105385. [PMID: 33991647 DOI: 10.1016/j.nbd.2021.105385] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/10/2021] [Accepted: 04/30/2021] [Indexed: 01/21/2023] Open
Abstract
Spinal cord injury (SCI) is a devastating condition characterized by loss of function, secondary to damaged spinal neurons, disrupted axonal connections, and myelin loss. Spontaneous recovery is limited, and there are no approved pharmaceutical treatments to reduce ongoing damage or promote repair. Repulsive guidance molecule A (RGMa) is upregulated following injury to the central nervous system (CNS), where it is believed to induce neuronal apoptosis and inhibit axonal growth and remyelination. We evaluated elezanumab, a human anti-RGMa monoclonal antibody, in a novel, newly characterized non-human primate (NHP) hemicompression model of thoracic SCI. Systemic intravenous (IV) administration of elezanumab over 6 months was well tolerated and associated with significant improvements in locomotor function. Treatment of animals for 16 weeks with a continuous intrathecal infusion of elezanumab below the lesion was not efficacious. IV elezanumab improved microstructural integrity of extralesional tissue as reflected by higher fractional anisotropy and magnetization transfer ratios in treated vs. untreated animals. IV elezanumab also reduced SCI-induced increases in soluble RGMa in cerebrospinal fluid, and membrane bound RGMa rostral and caudal to the lesion. Anterograde tracing of the corticospinal tract (CST) from the contralesional motor cortex following 20 weeks of IV elezanumab revealed a significant increase in the density of CST fibers emerging from the ipsilesional CST into the medial/ventral gray matter. There was a significant sprouting of serotonergic (5-HT) fibers rostral to the injury and in the ventral horn of lower thoracic regions. These data demonstrate that 6 months of intermittent IV administration of elezanumab, beginning within 24 h after a thoracic SCI, promotes neuroprotection and neuroplasticity of key descending pathways involved in locomotion. These findings emphasize the mechanisms leading to improved recovery of neuromotor functions with elezanumab in acute SCI in NHPs.
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Affiliation(s)
- Peer B Jacobson
- Department of Translational Sciences, Imaging Research, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America.
| | - Robin Goody
- Virscio, New Haven, CT, United States of America
| | | | - Bernhard K Mueller
- Discovery Biology, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Xiaomeng Zhang
- Department of Translational Sciences, Imaging Research, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Bradley A Hooker
- Department of Translational Sciences, Imaging Research, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Kimberly Pfleeger
- Department of Neuroscience Development, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Adam Ziemann
- Department of Neuroscience Development, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Charles Locke
- Department of Biometrics, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Quentin Barraud
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland; Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland; Defitech Center for Interventional Neurotherapies, (NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Mathias Droescher
- Discovery Biology, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Joerg Bernhard
- Discovery Biology, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Andreas Popp
- Department of Preclinical Safety, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Preethne Boeser
- Department of Preclinical Safety, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Lili Huang
- AbbVie Biologics, AbbVie Bioresearch Center, 381 Plantation St., Worcester, MA 01605, United States of America
| | - Jennifer Mollon
- Data and Statistical Sciences, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Yulia Mordashova
- Data and Statistical Sciences, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Yi-Fang Cui
- Discovery Biology, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - John P Savaryn
- Department of Drug Metabolism and Pharmacokinetics, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Christine Grinnell
- Department of Drug Metabolism and Pharmacokinetics, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Ingeborg Dreher
- Department of Bioanalytics, AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Michael Gold
- Department of Neuroscience Development, AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States of America
| | - Grégoire Courtine
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland; Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland; Defitech Center for Interventional Neurotherapies, (NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Andrea Mothe
- Krembil Brain Institute, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Charles H Tator
- Division of Neurosurgery, Toronto Western Hospital, and University of Toronto, Toronto, Canada
| | - James D Guest
- Department of Neurosurgery and The Miami Project to Cure Paralysis, The Miller School of Medicine, University of Miami, Miami, FL, United States of America
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6
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Hernandez‐Fuentes MP, Franklin C, Rebollo‐Mesa I, Mollon J, Delaney F, Perucha E, Stapleton C, Borrows R, Byrne C, Cavalleri G, Clarke B, Clatworthy M, Feehally J, Fuggle S, Gagliano SA, Griffin S, Hammad A, Higgins R, Jardine A, Keogan M, Leach T, MacPhee I, Mark PB, Marsh J, Maxwell P, McKane W, McLean A, Newstead C, Augustine T, Phelan P, Powis S, Rowe P, Sheerin N, Solomon E, Stephens H, Thuraisingham R, Trembath R, Topham P, Vaughan R, Sacks SH, Conlon P, Opelz G, Soranzo N, Weale ME, Lord GM. Long- and short-term outcomes in renal allografts with deceased donors: A large recipient and donor genome-wide association study. Am J Transplant 2018; 18:1370-1379. [PMID: 29392897 PMCID: PMC6001640 DOI: 10.1111/ajt.14594] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/28/2017] [Accepted: 11/13/2017] [Indexed: 01/25/2023]
Abstract
Improvements in immunosuppression have modified short-term survival of deceased-donor allografts, but not their rate of long-term failure. Mismatches between donor and recipient HLA play an important role in the acute and chronic allogeneic immune response against the graft. Perfect matching at clinically relevant HLA loci does not obviate the need for immunosuppression, suggesting that additional genetic variation plays a critical role in both short- and long-term graft outcomes. By combining patient data and samples from supranational cohorts across the United Kingdom and European Union, we performed the first large-scale genome-wide association study analyzing both donor and recipient DNA in 2094 complete renal transplant-pairs with replication in 5866 complete pairs. We studied deceased-donor grafts allocated on the basis of preferential HLA matching, which provided some control for HLA genetic effects. No strong donor or recipient genetic effects contributing to long- or short-term allograft survival were found outside the HLA region. We discuss the implications for future research and clinical application.
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Affiliation(s)
| | | | | | - Jennifer Mollon
- King's College LondonMRC Centre for TransplantationLondonUK,Department of HaematologyUniversity of Cambridge, Cambridge, UK
| | - Florence Delaney
- King's College LondonMRC Centre for TransplantationLondonUK,NIHR Biomedical Research Centre at Guy's and St Thomas’NHS Foundation Trust and King's College LondonLondonUK
| | | | | | - Richard Borrows
- Renal Institute of BirminghamDepartment of Nephrology and TransplantationBirminghamUK
| | - Catherine Byrne
- Nottingham Renal and Transplant UnitNottingham University Hospitals NHS TrustNottinghamUK
| | | | - Brendan Clarke
- Transplant and Cellular ImmunologyLeeds Teaching Hospitals NHS TrustLeedsUK
| | | | | | - Susan Fuggle
- Transplant Immunology & ImmunogeneticsChurchill HospitalOxfordUK
| | - Sarah A. Gagliano
- Center for Statistical GeneticsDepartment of BiostatisticsUniversity of MichiganAnn ArborMIUSA
| | - Sian Griffin
- Cardiff & Vale University Health BoardCardiff UniversityCardiffUK
| | - Abdul Hammad
- The Royal Liverpool and Broadgreen University HospitalsLiverpoolUK
| | - Robert Higgins
- University Hospitals Coventry and Warwickshire NHS TrustCoventryUK
| | - Alan Jardine
- School of MedicineDentistry and NursingUniversity of GlasgowGlasgowUK
| | | | | | | | - Patrick B. Mark
- School of MedicineDentistry and NursingUniversity of GlasgowGlasgowUK
| | - James Marsh
- Epsom and St Helier University Hospitals TrustCarshaltonUK
| | - Peter Maxwell
- School of MedicineDentistry and Biomedical SciencesQueens University BelfastBelfastUK
| | - William McKane
- Sheffield Kidney InstituteSheffield Teaching Hospitals NHS Foundation TrustSheffieldUK
| | - Adam McLean
- Kidney and TransplantImperial College Healthcare NHS TrustLondonUK
| | | | - Titus Augustine
- Central Manchester University Hospitals NHS TrustManchesterUK
| | | | - Steve Powis
- Division of MedicineUniversity College LondonLondonUK
| | | | - Neil Sheerin
- The Medical SchoolNewcastle University NewcastleNewcastle upon TyneUK
| | - Ellen Solomon
- Division of Genetics& Molecular MedicineKing's College LondonLondonUK
| | | | | | - Richard Trembath
- Division of Genetics& Molecular MedicineKing's College LondonLondonUK
| | | | - Robert Vaughan
- Clinical Transplantation Laboratory at Guy's HospitalGuy's and St Thomas’ NHS TrustLondonUK
| | - Steven H. Sacks
- King's College LondonMRC Centre for TransplantationLondonUK,NIHR Biomedical Research Centre at Guy's and St Thomas’NHS Foundation Trust and King's College LondonLondonUK
| | - Peter Conlon
- Royal College of Surgeons in IrelandDublinIreland,Beaumont HospitalDublinIreland
| | - Gerhard Opelz
- University of HeidelbergTransplantation ImmunologyHeidelbergGermany
| | - Nicole Soranzo
- Welcome Trust Sanger InstituteHuman GeneticsCambridgeUK,Department of HaematologyUniversity of Cambridge, Cambridge, UK
| | - Michael E. Weale
- Division of Genetics& Molecular MedicineKing's College LondonLondonUK,Present address:
Genomics plcOxfordUK
| | - Graham M. Lord
- King's College LondonMRC Centre for TransplantationLondonUK,NIHR Biomedical Research Centre at Guy's and St Thomas’NHS Foundation Trust and King's College LondonLondonUK
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7
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Abstract
Schizophrenia patients commonly exhibit substantial and diffuse cognitive impairment. Evidence suggests that subtle cognitive deficits are already apparent in childhood and adolescence, many years prior to onset of psychosis. While there is almost unequivocal evidence of some degree of cognitive impairment in individuals who later develop schizophrenia, the literature remains inconclusive regarding the exact nature of this impairment and warrants careful review and interpretation. Meta-analytic findings suggest that individuals who later develop schizophrenia, but not related disorders, such as bipolar disorder, exhibit a premorbid IQ deficit of around 8 points. Several studies have also found evidence for premorbid deficits across most cognitive domains, such as language, processing speed and executive functions. Longitudinal studies, although rare, suggest that individuals who go on to develop schizophrenia may show a course of increasing cognitive impairment prior to onset of psychosis. While evidence regarding the etiology of premorbid deficits is scarce, common and rare genetic variants, as well as environmental factors such as obstetric complications and cannabis use may play an important role and warrant further examination. In this selected review, we give an overview of population-based studies on premorbid cognitive deficits in schizophrenia, with a special focus on evidence regarding the specificity, profile and course of these deficits.
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Affiliation(s)
- J Mollon
- Department of Psychosis Studies,Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK
| | - A Reichenberg
- Department of Psychosis Studies,Institute of Psychiatry, Psychology and Neuroscience, King's College London,London,UK
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8
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Modabbernia A, Velthorst E, Gennings C, De Haan L, Austin C, Sutterland A, Mollon J, Frangou S, Wright R, Arora M, Reichenberg A. Early-life metal exposure and schizophrenia: A proof-of-concept study using novel tooth-matrix biomarkers. Eur Psychiatry 2016; 36:1-6. [PMID: 27311101 DOI: 10.1016/j.eurpsy.2016.03.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/15/2016] [Accepted: 03/21/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Despite evidence for the effects of metals on neurodevelopment, the long-term effects on mental health remain unclear due to methodological limitations. Our objective was to determine the feasibility of studying metal exposure during critical neurodevelopmental periods and to explore the association between early-life metal exposure and adult schizophrenia. METHODS We analyzed childhood-shed teeth from nine individuals with schizophrenia and five healthy controls. We investigated the association between exposure to lead (Pb(2+)), manganese (Mn(2+)), cadmium (Cd(2+)), copper (Cu(2+)), magnesium (Mg(2+)), and zinc (Zn(2+)), and schizophrenia, psychotic experiences, and intelligence quotient (IQ). We reconstructed the dose and timing of early-life metal exposures using laser ablation inductively coupled plasma mass spectrometry. RESULTS We found higher early-life Pb(2+) exposure among patients with schizophrenia than controls. The differences in log Mn(2+) and log Cu(2+) changed relatively linearly over time to postnatal negative values. There was a positive correlation between early-life Pb(2+) levels and psychotic experiences in adulthood. Moreover, we found a negative correlation between Pb(2+) levels and adult IQ. CONCLUSIONS In our proof-of-concept study, using tooth-matrix biomarker that provides direct measurement of exposure in the fetus and newborn, we provide support for the role of metal exposure during critical neurodevelopmental periods in psychosis.
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Affiliation(s)
- A Modabbernia
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, United States; Seaver Center for Autism Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, United States; Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, United States.
| | - E Velthorst
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, United States; Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - C Gennings
- Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, United States
| | - L De Haan
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - C Austin
- Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, United States
| | - A Sutterland
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - J Mollon
- Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, England, United Kingdom
| | - S Frangou
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, United States; Psychosis Research Program, Icahn School of Medicine at Mount Sinai, New York, United States
| | - R Wright
- Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, United States
| | - M Arora
- Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, United States
| | - A Reichenberg
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, United States; Seaver Center for Autism Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, United States; Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, United States; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, United States
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Danilova M, Mollon J. A chromatic channel in which short-wave and long-wave cone signals are opposed to middle-wave cone signals? J Vis 2014. [DOI: 10.1167/14.15.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Bargary G, Lawrance-Owen A, Goodbourn P, Bosten J, Mollon J. A potassium ion channel associated with variation in the accuracy of ocular tracking. J Vis 2014. [DOI: 10.1167/14.15.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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11
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Chouraki VA, Jakobsdottir J, Mather K, Adams H, Mollon J, Oldmeadow C, Thalamuthu A, Tanaka T, Scott R, Levy D, Holliday L, Song F, Thambisetty M, Poljak A, Eiriksdottir G, Sachdev PS, Gupta VB, Martins R, Launer L, Dobson R, Brodaty H, Attia J, Lovestone S, Gudnason V, Ikram M, Seshadri S. P3‐071: A GENOME‐WIDE META‐ANALYSIS OF PLASMA CLUSTERIN LEVELS IN THE CHARGE CONSORTIUM. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.1159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Daniel Levy
- The Framingham Heart StudyFraminghamMassachusettsUnited States
| | | | - Fei Song
- University of New South WalesSydneyAustralia
| | | | | | | | | | | | | | - Lenore Launer
- National Institute on AgingBethesdaMarylandUnited States
| | | | - Henry Brodaty
- Dementia Collaborative Research CentreSydneyAustralia
| | - John Attia
- University of NewcastleNewcastleAustralia
| | | | | | | | - Sudha Seshadri
- Boston University School of MedicineBostonMassachusettsUnited States
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Danilova M, Mollon J. Chromatic discrimination at phenomenological category boundaries: The case of unique red. J Vis 2013. [DOI: 10.1167/13.15.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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13
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Mollon J, Bargary G, Goodbourn P, Lawrance-Owen A, Bosten J. An oculomotor signature. J Vis 2013. [DOI: 10.1167/13.15.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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Danilova M, Mollon J. The anisotropy of color space. J Vis 2013. [DOI: 10.1167/13.9.294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Villanova F, Di Meglio P, Inokuma M, Aghaeepour N, Perucha E, Mollon J, Nomura L, Hernandez-Fuentes M, Cope A, Prevost AT, Heck S, Maino V, Lord G, Brinkman RR, Nestle FO. Integration of lyoplate based flow cytometry and computational analysis for standardized immunological biomarker discovery. PLoS One 2013; 8:e65485. [PMID: 23843942 PMCID: PMC3701052 DOI: 10.1371/journal.pone.0065485] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/23/2013] [Indexed: 12/29/2022] Open
Abstract
Discovery of novel immune biomarkers for monitoring of disease prognosis and response to therapy in immune-mediated inflammatory diseases is an important unmet clinical need. Here, we establish a novel framework for immunological biomarker discovery, comparing a conventional (liquid) flow cytometry platform (CFP) and a unique lyoplate-based flow cytometry platform (LFP) in combination with advanced computational data analysis. We demonstrate that LFP had higher sensitivity compared to CFP, with increased detection of cytokines (IFN-γ and IL-10) and activation markers (Foxp3 and CD25). Fluorescent intensity of cells stained with lyophilized antibodies was increased compared to cells stained with liquid antibodies. LFP, using a plate loader, allowed medium-throughput processing of samples with comparable intra- and inter-assay variability between platforms. Automated computational analysis identified novel immunophenotypes that were not detected with manual analysis. Our results establish a new flow cytometry platform for standardized and rapid immunological biomarker discovery with wide application to immune-mediated diseases.
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Affiliation(s)
- Federica Villanova
- St. John's Institute of Dermatology, King's College London, London, United Kingdom
- National Institute for Health Research, Comprehensive Biomedical Research Centre, Guy's & St. Thomas' NHS Foundation Trust, (NIHR GSTT/KCL) London, United Kingdom
| | - Paola Di Meglio
- St. John's Institute of Dermatology, King's College London, London, United Kingdom
- National Institute for Health Research, Comprehensive Biomedical Research Centre, Guy's & St. Thomas' NHS Foundation Trust, (NIHR GSTT/KCL) London, United Kingdom
- Molecular Immunology, National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Margaret Inokuma
- Biological Research & Development, BD Biosciences, San Jose, California, United States of America
| | - Nima Aghaeepour
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, Canada
| | - Esperanza Perucha
- The Medical Research Council (MRC) Centre for Transplantation, King's College London, London, United Kingdom
| | - Jennifer Mollon
- Division of Genetics and Molecular Medicine, Statistical Genetics Unit, King's College London, London, United Kingdom
| | - Laurel Nomura
- Biological Research & Development, BD Biosciences, San Jose, California, United States of America
| | - Maria Hernandez-Fuentes
- National Institute for Health Research, Comprehensive Biomedical Research Centre, Guy's & St. Thomas' NHS Foundation Trust, (NIHR GSTT/KCL) London, United Kingdom
- The Medical Research Council (MRC) Centre for Transplantation, King's College London, London, United Kingdom
| | - Andrew Cope
- Academic Department of Rheumatology, King's College London, London United Kingdom
| | - A. Toby Prevost
- Department of Primary Care and Public Health Sciences, King's College London, London, United Kingdom
| | - Susanne Heck
- National Institute for Health Research, Comprehensive Biomedical Research Centre, Guy's & St. Thomas' NHS Foundation Trust, (NIHR GSTT/KCL) London, United Kingdom
| | - Vernon Maino
- Biological Research & Development, BD Biosciences, San Jose, California, United States of America
| | - Graham Lord
- National Institute for Health Research, Comprehensive Biomedical Research Centre, Guy's & St. Thomas' NHS Foundation Trust, (NIHR GSTT/KCL) London, United Kingdom
- The Medical Research Council (MRC) Centre for Transplantation, King's College London, London, United Kingdom
| | - Ryan R. Brinkman
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Frank O. Nestle
- St. John's Institute of Dermatology, King's College London, London, United Kingdom
- National Institute for Health Research, Comprehensive Biomedical Research Centre, Guy's & St. Thomas' NHS Foundation Trust, (NIHR GSTT/KCL) London, United Kingdom
- * E-mail:
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Mollon J, Danilova M. A paradox of color discrimination. J Vis 2011. [DOI: 10.1167/11.15.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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17
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Danilova M, Chan C, Mollon J. Individual differences in cone ratio: Measurements by counterphase modulation photometry and by spatial acuity. J Vis 2011. [DOI: 10.1167/11.15.33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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18
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Danilova M, Mollon J. Enhanced color discrimination in the vicinity of the caerulean line. J Vis 2009. [DOI: 10.1167/9.14.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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19
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Blake Z, Land T, Mollon J. Relative latencies of cone signals measured by a moving vernier task. J Vis 2008; 8:16.1-11. [DOI: 10.1167/8.16.16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 09/26/2008] [Indexed: 11/24/2022] Open
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McManus IC, Elder AT, de Champlain A, Dacre JE, Mollon J, Chis L. Graduates of different UK medical schools show substantial differences in performance on MRCP(UK) Part 1, Part 2 and PACES examinations. BMC Med 2008; 6:5. [PMID: 18275598 PMCID: PMC2265293 DOI: 10.1186/1741-7015-6-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 02/14/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The UK General Medical Council has emphasized the lack of evidence on whether graduates from different UK medical schools perform differently in their clinical careers. Here we assess the performance of UK graduates who have taken MRCP(UK) Part 1 and Part 2, which are multiple-choice assessments, and PACES, an assessment using real and simulated patients of clinical examination skills and communication skills, and we explore the reasons for the differences between medical schools. METHOD We perform a retrospective analysis of the performance of 5827 doctors graduating in UK medical schools taking the Part 1, Part 2 or PACES for the first time between 2003/2 and 2005/3, and 22453 candidates taking Part 1 from 1989/1 to 2005/3. RESULTS Graduates of UK medical schools performed differently in the MRCP(UK) examination between 2003/2 and 2005/3. Part 1 and 2 performance of Oxford, Cambridge and Newcastle-upon-Tyne graduates was significantly better than average, and the performance of Liverpool, Dundee, Belfast and Aberdeen graduates was significantly worse than average. In the PACES (clinical) examination, Oxford graduates performed significantly above average, and Dundee, Liverpool and London graduates significantly below average. About 60% of medical school variance was explained by differences in pre-admission qualifications, although the remaining variance was still significant, with graduates from Leicester, Oxford, Birmingham, Newcastle-upon-Tyne and London overperforming at Part 1, and graduates from Southampton, Dundee, Aberdeen, Liverpool and Belfast underperforming relative to pre-admission qualifications. The ranking of schools at Part 1 in 2003/2 to 2005/3 correlated 0.723, 0.654, 0.618 and 0.493 with performance in 1999-2001, 1996-1998, 1993-1995 and 1989-1992, respectively. CONCLUSION Candidates from different UK medical schools perform differently in all three parts of the MRCP(UK) examination, with the ordering consistent across the parts of the exam and with the differences in Part 1 performance being consistent from 1989 to 2005. Although pre-admission qualifications explained some of the medical school variance, the remaining differences do not seem to result from career preference or other selection biases, and are presumed to result from unmeasured differences in ability at entry to the medical school or to differences between medical schools in teaching focus, content and approaches. Exploration of causal mechanisms would be enhanced by results from a national medical qualifying examination.
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Affiliation(s)
- I C McManus
- Department of Psychology, University College London, Gower Street, London WC1E 6BT, UK.
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Dewhurst NG, McManus C, Mollon J, Dacre JE, Vale AJ. Performance in the MRCP(UK) Examination 2003-4: analysis of pass rates of UK graduates in relation to self-declared ethnicity and gender. BMC Med 2007; 5:8. [PMID: 17477862 PMCID: PMC1871601 DOI: 10.1186/1741-7015-5-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 05/03/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Male students and students from ethnic minorities have been reported to under-perform in undergraduate medical examinations. We examined the effects of ethnicity and gender on pass rates in UK medical graduates sitting the Membership of the Royal Colleges of Physicians in the United Kingdom [MRCP(UK)] Examination in 2003-4. METHODS Pass rates for each part of the examination were analysed for differences between graduate groupings based on self-declared ethnicity and gender. RESULTS All candidates declared their gender, and 84-90% declared their ethnicity. In all three parts of the examination, white candidates performed better than other ethnic groups (P < 0.001). In the MRCP(UK) Part 1 and Part 2 Written Examinations, there was no significant difference in pass rate between male and female graduates, nor was there any interaction between gender and ethnicity. In the Part 2 Clinical Examination (Practical Assessment of Clinical Examination Skills, PACES), women performed better than did men (P < 0.001). Non-white men performed more poorly than expected, relative to white men or non-white women. Analysis of individual station marks showed significant interaction between candidate and examiner ethnicity for performance on communication skills (P = 0.011), but not on clinical skills (P = 0.176). Analysis of overall average marks showed no interaction between candidate gender and the number of assessments made by female examiners (P = 0.151). CONCLUSION The cause of these differences is most likely to be multifactorial, but cannot be readily explained in terms of previous educational experience or differential performance on particular parts of the examination. Potential examiner prejudice, significant only in the cases where there were two non-white examiners and the candidate was non-white, might indicate different cultural interpretations of the judgements being made.
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Affiliation(s)
- Neil G Dewhurst
- MRCP(UK) Central Office, 11, St. Andrew's Place, London NW1 4LE, UK
| | - Chris McManus
- Department of Psychology, University College London, UK
| | - Jennifer Mollon
- MRCP(UK) Central Office, 11, St. Andrew's Place, London NW1 4LE, UK
| | - Jane E Dacre
- Academic Centre for Medical Education (ACME), University College London, UK
| | - Allister J Vale
- MRCP(UK) Central Office, 11, St. Andrew's Place, London NW1 4LE, UK
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McManus IC, Thompson M, Mollon J. Assessment of examiner leniency and stringency ('hawk-dove effect') in the MRCP(UK) clinical examination (PACES) using multi-facet Rasch modelling. BMC Med Educ 2006; 6:42. [PMID: 16919156 PMCID: PMC1569374 DOI: 10.1186/1472-6920-6-42] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Accepted: 08/18/2006] [Indexed: 05/11/2023]
Abstract
BACKGROUND A potential problem of clinical examinations is known as the hawk-dove problem, some examiners being more stringent and requiring a higher performance than other examiners who are more lenient. Although the problem has been known qualitatively for at least a century, we know of no previous statistical estimation of the size of the effect in a large-scale, high-stakes examination. Here we use FACETS to carry out a multi-facet Rasch modelling of the paired judgements made by examiners in the clinical examination (PACES) of MRCP(UK), where identical candidates were assessed in identical situations, allowing calculation of examiner stringency. METHODS Data were analysed from the first nine diets of PACES, which were taken between June 2001 and March 2004 by 10,145 candidates. Each candidate was assessed by two examiners on each of seven separate tasks. with the candidates assessed by a total of 1,259 examiners, resulting in a total of 142,030 marks. Examiner demographics were described in terms of age, sex, ethnicity, and total number of candidates examined. RESULTS FACETS suggested that about 87% of main effect variance was due to candidate differences, 1% due to station differences, and 12% due to differences between examiners in leniency-stringency. Multiple regression suggested that greater examiner stringency was associated with greater examiner experience and being from an ethnic minority. Male and female examiners showed no overall difference in stringency. Examination scores were adjusted for examiner stringency and it was shown that for the present pass mark, the outcome for 95.9% of candidates would be unchanged using adjusted marks, whereas 2.6% of candidates would have passed, even though they had failed on the basis of raw marks, and 1.5% of candidates would have failed, despite passing on the basis of raw marks. CONCLUSION Examiners do differ in their leniency or stringency, and the effect can be estimated using Rasch modelling. The reasons for differences are not clear, but there are some demographic correlates, and the effects appear to be reliable across time. Account can be taken of differences, either by adjusting marks or, perhaps more effectively and more justifiably, by pairing high and low stringency examiners, so that raw marks can be used in the determination of pass and fail.
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Affiliation(s)
- IC McManus
- Department of Psychology, University College London, Gower Street, London WC1E 6BT, UK
| | - M Thompson
- MRCP(UK) Central Office, 11 St Andrews Place, Regents Park, London NW1 4LE, UK
| | - J Mollon
- MRCP(UK) Central Office, 11 St Andrews Place, Regents Park, London NW1 4LE, UK
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McManus IC, Mollon J, Duke OL, Vale JA. Changes in standard of candidates taking the MRCP(UK) Part 1 examination, 1985 to 2002: analysis of marker questions. BMC Med 2005; 3:13. [PMID: 16026607 PMCID: PMC1185541 DOI: 10.1186/1741-7015-3-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 07/18/2005] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The maintenance of standards is a problem for postgraduate medical examinations, particularly if they use norm-referencing as the sole method of standard setting. In each of its diets, the MRCP(UK) Part 1 Examination includes a number of marker questions, which are unchanged from their use in a previous diet. This paper describes two complementary studies of marker questions for 52 diets of the MRCP(UK) Part 1 Examination over the years 1985 to 2001 to assess whether standards have changed. METHODS Study 1, which used routinely collected information on the performance of 4405 marker items, used a statistical method to assess changes in performance across diets. Study 2 compared performances of individual candidates on 28 individual marker items that were shared by the 1996/2 and 2001/3 diets. RESULTS Study 1 found evidence that candidate performance on the MRCP(UK) Part 1 Examination showed a gradual improvement over the period 1985 to 1997, which was followed by a sharp decline in performance until 2001. The 'dog-leg' in performance at 1997/3 was not an artefact of changed Examination Regulations, mix of UK and overseas candidates, or time from qualification until taking the Examination. Study 2 confirmed that performance in 2001/3 was significantly worse than in 1996/3, that the poorer performance was found in graduates of UK medical schools, and that candidates passing the Examination in 2001/3 performed less well than those passing in 1996/2. CONCLUSION There has been a decline in the performance of graduates from UK medical schools taking the MRCP(UK) Part 1 examination. The reasons for this are not clear, but the finding has implications for medical education, and further studies are needed of performance in other postgraduate and undergraduate examinations. The use of norm-referencing as the sole method for setting the pass mark over this period meant that candidates passing the MRCP(UK) examination also had a lower standard. The MRCP(UK) Part 1 and Part 2 examinations now have their standard set by criterion-referencing.
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Affiliation(s)
- IC McManus
- Dept of Psychology, University College London, Gower Street, London WC1E 6BT, UK
| | - J Mollon
- MRCP(UK) Central Office, 11 St Andrews Place, Regents Park, London NW1 4LE, UK
| | - OL Duke
- MRCP(UK) Central Office, 11 St Andrews Place, Regents Park, London NW1 4LE, UK
| | - JA Vale
- MRCP(UK) Central Office, 11 St Andrews Place, Regents Park, London NW1 4LE, UK
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Smithson H, Bourke A, Zaidi Q, Mollon J, Stockman A. Three ways to find a tritan line. J Vis 2004. [DOI: 10.1167/4.11.83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Stockman A, Mollon J. The spectral sensitivities of the middle- and long-wavelength cones: an extension of the two-colour threshold technique of W S Stiles. Perception 1986; 15:729-54. [PMID: 3658626 DOI: 10.1068/p150729] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
When a tiny centred test flash is presented on a small concentric background, the threshold rises with background radiance more quickly than Weber's law would predict. It is argued that under such conditions it is possible, by means of a test sensitivity method, to isolate either the M-cone or the L-cone types throughout the visible spectrum. As predicted, double-branched M- and L-cone tyr functions are found when the test flash and the field are of the same wavelength. From the independent vertical displacements of the two branches as test wavelength is varied, it is possible to derive spectral sensitivities that agree well with dichromatic sensitivities and König fundamentals. The test sensitivities deviate from pi 4 at longer wavelengths and from pi 5 at shorter wavelengths.
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Affiliation(s)
- A Stockman
- Psychological Laboratory, University of Cambridge, UK
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Affiliation(s)
- J Mollon
- Department of Experimental Psychology, University of Cambridge, UK
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