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102
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Braeuninger S, Kleinschnitz C. Rodent models of focal cerebral ischemia: procedural pitfalls and translational problems. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2009; 1:8. [PMID: 20150986 PMCID: PMC2820446 DOI: 10.1186/2040-7378-1-8] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 11/25/2009] [Indexed: 11/10/2022]
Abstract
Rodent models of focal cerebral ischemia are essential tools in experimental stroke research. They have added tremendously to our understanding of injury mechanisms in stroke and have helped to identify potential therapeutic targets. A plethora of substances, however, in particular an overwhelming number of putative neuroprotective agents, have been shown to be effective in preclinical stroke research, but have failed in clinical trials. A lot of factors may have contributed to this failure of translation from bench to bedside. Often, deficits in the quality of experimental stroke research seem to be involved. In this article, we review the commonest rodent models of focal cerebral ischemia - middle cerebral artery occlusion, photothrombosis, and embolic stroke models - with their respective advantages and problems, and we address the issue of quality in preclinical stroke modeling as well as potential reasons for translational failure.
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Affiliation(s)
- Stefan Braeuninger
- Department of Neurology, Julius-Maximilians-Universitaet Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany.
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103
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Granulocyte-colony stimulating factor for stroke treatment: mechanisms of action and efficacy in preclinical studies. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2009; 1:2. [PMID: 20142989 PMCID: PMC2816868 DOI: 10.1186/2040-7378-1-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 10/21/2009] [Indexed: 01/22/2023]
Abstract
G-CSF is widely employed for the treatment of chemotherapy-induced neutropenia. Recently, neuroprotective effects of G-CSF in animal stroke models were discovered including infarct size reduction and enhancement of functional recovery. The underlying mechanisms of action of G-CSF in ischemia appear to be a direct anti-apoptotic activity in neurons and a neurogenesis inducing capacity. Additional effects may be based on the stimulation of new blood-vessel formation, the stimulation of immunocompetence and -modulation as well as on bone marrow mobilization. In addition to a discussion of these mechanisms, we will review the available preclinical studies and analyze their impact on the overall efficacy of G-CSF in experimental stroke.
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104
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Kimmelman J, London AJ, Ravina B, Ramsay T, Bernstein M, Fine A, Stahnisch FW, Emborg ME. Launching invasive, first-in-human trials against Parkinson's disease: ethical considerations. Mov Disord 2009; 24:1893-901. [PMID: 19672990 PMCID: PMC2989599 DOI: 10.1002/mds.22712] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The decision to initiate invasive, first-in-human trials involving Parkinson's disease presents a vexing ethical challenge. Such studies present significant surgical risks, and high degrees of uncertainty about intervention risks and biological effects. We argue that maintaining a favorable risk-benefit balance in such circumstances requires a higher than usual degree of confidence that protocols will lead to significant direct and/or social benefits. One critical way of promoting such confidence is through the application of stringent evidentiary standards for preclinical studies. We close with a series of recommendations for strengthening the internal and external validity of preclinical studies, reducing their tendency toward optimism and publication biases, and improving the knowledge base used to design and evaluate preclinical studies.
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Affiliation(s)
- Jonathan Kimmelman
- Biomedical Ethics Unit, Department of Social Studies of Medicine, McGill University, 3647 Peel Street, Montreal, QB H3A 1X1, Canada.
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105
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Systematic Review and Stratified Meta-analysis of the Efficacy of Interleukin-1 Receptor Antagonist in Animal Models of Stroke. J Stroke Cerebrovasc Dis 2009; 18:269-76. [DOI: 10.1016/j.jstrokecerebrovasdis.2008.11.009] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 11/14/2008] [Accepted: 11/18/2008] [Indexed: 11/23/2022] Open
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106
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Bracken MB. Why animal studies are often poor predictors of human reactions to exposure. J R Soc Med 2009; 102:120-2. [PMID: 19297654 DOI: 10.1258/jrsm.2008.08k033] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Michael B Bracken
- Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University Schools of Medicine and Public Health, 1 Church Street, New Haven, CT 06510, USA.
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107
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Fisher M, Feuerstein G, Howells DW, Hurn PD, Kent TA, Savitz SI, Lo EH. Update of the stroke therapy academic industry roundtable preclinical recommendations. Stroke 2009; 40:2244-50. [PMID: 19246690 PMCID: PMC2888275 DOI: 10.1161/strokeaha.108.541128] [Citation(s) in RCA: 986] [Impact Index Per Article: 65.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The initial Stroke Therapy Academic Industry Roundtable (STAIR) recommendations published in 1999 were intended to improve the quality of preclinical studies of purported acute stroke therapies. Although recognized as reasonable, they have not been closely followed nor rigorously validated. Substantial advances have occurred regarding the appropriate quality and breadth of preclinical testing for candidate acute stroke therapies for better clinical translation. The updated STAIR preclinical recommendations reinforce the previous suggestions that reproducibly defining dose response and time windows with both histological and functional outcomes in multiple animal species with appropriate physiological monitoring is appropriate. The updated STAIR recommendations include: the fundamentals of good scientific inquiry should be followed by eliminating randomization and assessment bias, a priori defining inclusion/exclusion criteria, performing appropriate power and sample size calculations, and disclosing potential conflicts of interest. After initial evaluations in young, healthy male animals, further studies should be performed in females, aged animals, and animals with comorbid conditions such as hypertension, diabetes, and hypercholesterolemia. Another consideration is the use of clinically relevant biomarkers in animal studies. Although the recommendations cannot be validated until effective therapies based on them emerge from clinical trials, it is hoped that adherence to them might enhance the chances for success.
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Affiliation(s)
- Marc Fisher
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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108
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Bracken MB. Why are so many epidemiology associations inflated or wrong? Does poorly conducted animal research suggest implausible hypotheses? Ann Epidemiol 2009; 19:220-4. [PMID: 19217006 DOI: 10.1016/j.annepidem.2008.11.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 11/29/2008] [Indexed: 01/31/2023]
Abstract
There is growing concern among epidemiologists that most discovered associations are either inflated or false. The reasons for this concern have focused on methodological issues in the conduct and publication of epidemiologic research. This commentary suggests that another reason for discrepant findings may be that animal research is producing implausible hypotheses. Many animal studies are methodologically weak, and the animal literature is not systematically reviewed and synthesized. Moreover, most bodies of animal literature may be so heterogeneous that they can be used selectively to support the plausibility of almost any epidemiology study result. Epidemiologists themselves also do not consistently conduct systematic reviews of bodies of biological evidence which might point to sources of bias in an evidence base. Animal research will likely continue to provide the biological basis for epidemiological investigation, but substantial improvement is needed in how it is conducted and synthesized to improve the predictability of animal studies for the human condition.
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Affiliation(s)
- Michael B Bracken
- School of Public Health and Medicine, Yale University, New Haven, CT, USA
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109
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Bath PMW, Gray LJ, Bath AJG, Buchan A, Miyata T, Green AR. Effects of NXY-059 in experimental stroke: an individual animal meta-analysis. Br J Pharmacol 2009; 157:1157-71. [PMID: 19422398 DOI: 10.1111/j.1476-5381.2009.00196.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Disodium 2,4-disulphophenyl-N-tert-butylnitrone (NXY-059) was neuroprotective in experimental stroke models but ineffective in a large clinical trial. This first-ever individual animal meta-analysis was used to assess the preclinical studies. EXPERIMENTAL APPROACH Studies were obtained from AstraZeneca and PubMed searches. Data for each animal were obtained from the lead author of each study and/or AstraZeneca. Published summary data were used if individual data were not available. Infarct volume and motor impairment were standardized to reflect different species and scales. Standardized mean difference (SMD), coefficients from multilevel models and 95% confidence intervals (95% CI) are presented. KEY RESULTS Fifteen studies (26 conditions, 12 laboratories) involving rats (544), mice (9) and marmosets (32) were identified (NXY-059: 332, control: 253) with individual data for 442 animals. Four studies were unpublished. Studies variably used randomization (40%), blinding of surgeon (53%) and outcome assessor (67%). NXY-059 reduced total (SMD -1.17, 95% CI -1.50 to -0.84), cortical (SMD -2.17, 95% CI -2.99 to -1.34) and subcortical (-1.43, 95% CI -2.20 to -0.86) lesion volume; efficacy was seen in transient, permanent and thrombotic ischaemia, up to 180 min post occlusion. NXY-059 reduced motor impairment (SMD -1.66, 95% CI -2.18 to -1.14) and neglect. Evidence for performance, attrition and publication bias was present. CONCLUSIONS AND IMPLICATIONS NXY-059 was neuroprotective in experimental stroke although bias may have resulted in efficacy being overestimated. Efficacy in young, healthy, male animals is a poor predictor of clinical outcome. We suggest the use of preclinical meta-analysis before initiation of future clinical trials.
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Affiliation(s)
- P M W Bath
- Stroke Trials Unit, University of Nottingham, Clinical Sciences Building, City Hospital Campus, Hucknall Road, Nottingham, UK.
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110
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Bailey EL, McCulloch J, Sudlow C, Wardlaw JM. Potential animal models of lacunar stroke: a systematic review. Stroke 2009; 40:e451-8. [PMID: 19390080 DOI: 10.1161/strokeaha.108.528430] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Lacunar ischemic stroke accounts for 25% of all ischemic strokes, but the exact etiology is unknown. Numerous pathophysiologies have been proposed, including atheroma and endothelial dysfunction. Models of any of these pathological features would aid understanding of the etiology and help develop treatments for lacunar stroke. We therefore aimed to assess the relevance of all available potential animal models of lacunar stroke. METHODS We systematically reviewed the published literature for animal models that could represent lacunar stroke using validated search strategies. We included studies that could represent an aspect of lacunar stroke as well as those aiming to model conditions with potentially similar pathology and extracted data on species, induction method, and resulting brain and vessel lesions. RESULTS From 5670 papers, 41 studies (46 papers) met inclusion criteria representing over 10 different classes of stroke induction. Important data like infarct size and animal numbers were often missing. Many models' infarcts were too large or affected the cortex. Emboli mostly caused cortical but not small subcortical lesions. Most models focused on creating ischemic lesions in brain tissue. Only one (spontaneous lesions in spontaneously hypertensive stroke-prone rats) also mimicked small vessel pathology. Here, the precursor to small vessel and brain damage was blood-brain barrier failure. CONCLUSIONS Some animal models produce small subcortical infarcts, but few mimic the human small vessel pathology. Models of small vessel disease could help improve understanding of human lacunar disease, particularly to clarify factors associated with the small vessel morphological changes preceding brain damage. Much lacunar stroke may arise after blood-brain barrier disruption.
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Affiliation(s)
- Emma L Bailey
- Division of Clinical Neurosciences, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
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111
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Gibson CL, Coomber B, Rathbone J. Is progesterone a candidate neuroprotective factor for treatment following ischemic stroke? Neuroscientist 2009; 15:324-32. [PMID: 19359672 DOI: 10.1177/1073858409333069] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Gender differences in stroke outcome have implicated steroid hormones as potential neuroprotective candidates. However, no clinical trials examining hormone replacement therapy on outcome following ischemic stroke have investigated the effect of progesterone-only treatment. In this review the authors examine the experimental evidence for the neuroprotective potential of progesterone and give an insight into potential mechanisms of action following ischemic stroke. To date, 17 experimental studies have investigated the neuroprotective potential of progesterone for ischemic stroke in terms of ability to both reduce cell loss and increase functional outcome. Of these 17 published studies the majority reported a beneficial effect with three studies reporting a nil effect and only one study reporting a negative effect. However, there are important issues that the authors address in this review in terms of the methodological quality of studies in relation to the STAIR recommendations. In terms of the proposed mechanisms of progesterone neuroprotection we show that progesterone is versatile and acts at multiple targets to facilitate neuronal survival and minimize cell damage and loss. A large amount of experimental evidence indicates that progesterone is a neuroprotective candidate for ischemic stroke; however, to progress to clinical trial a number of key experimental studies remain outstanding.
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Affiliation(s)
- Claire L Gibson
- School of Psychology, University of Leicester, Leicester, United Kingdom.
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112
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Macleod MR, Fisher M, O'Collins V, Sena ES, Dirnagl U, Bath PMW, Buchan A, Worp HBVD, Traystman RJ, Minematsu K, Donnan GA, Howells DW. REPRINT: Good Laboratory Practice: Preventing Introduction of Bias at the Bench. Int J Stroke 2009; 4:3-5. [DOI: 10.1111/j.1747-4949.2009.00241.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
As a research community, we have failed to demonstrate that drugs that show substantial efficacy in animal models of cerebral ischemia can also improve outcome in human stroke. Accumulating evidence suggests that this may be due, at least in part, to problems in the design, conduct and reporting of animal experiments, which create a systematic bias resulting in the overstatement of neuroprotective efficacy. Here, we set out a series of measures to reduce bias in the design, conduct and reporting of animal experiments modeling human stroke.
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Affiliation(s)
- Malcolm R. Macleod
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Marc Fisher
- University of Massachusetts Medical School, Worcester, MA, USA
| | - Victoria O'Collins
- Department of Medicine, National Stroke Research Institute & University of Melbourne, Austin Health, Melbourne, Australia
| | - Emily S. Sena
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
- Department of Medicine, National Stroke Research Institute & University of Melbourne, Austin Health, Melbourne, Australia
| | - Ulrich Dirnagl
- Department for Experimental Neurology & Center for Stroke Research, Berlin, Germany
| | | | - Alistair Buchan
- Acute Stroke Program, Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, UK
| | - H. Bart van der Worp
- Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, The Netherlands
| | | | - Kazuo Minematsu
- Department of Medicine, National Cardiovascular Center, Cerebrovascular Division, Osaka, Japan
| | - Geoffrey A. Donnan
- Department of Medicine, National Stroke Research Institute & University of Melbourne, Austin Health, Melbourne, Australia
| | - David W. Howells
- Department of Medicine, National Stroke Research Institute & University of Melbourne, Austin Health, Melbourne, Australia
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113
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Macleod MR, Fisher M, O'Collins V, Sena ES, Dirnagl U, Bath PMW, Buchan A, van der Worp HB, Traystman RJ, Minematsu K, Donnan GA, Howells DW, Howells DW. Reprint: Good laboratory practice: preventing introduction of bias at the bench. J Cereb Blood Flow Metab 2009; 29:221-3. [PMID: 18797473 PMCID: PMC2729492 DOI: 10.1038/jcbfm.2008.101] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
As a research community, we have failed to show that drugs, which show substantial efficacy in animal models of cerebral ischemia, can also improve outcome in human stroke. Accumulating evidence suggests this may be due, at least in part, to problems in the design, conduct, and reporting of animal experiments which create a systematic bias resulting in the overstatement of neuroprotective efficacy. Here, we set out a series of measures to reduce bias in the design, conduct and reporting of animal experiments modeling human stroke.
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Affiliation(s)
- Malcolm R Macleod
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
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114
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Liu S. Dealing with publication bias in translational stroke research. JOURNAL OF EXPERIMENTAL STROKE & TRANSLATIONAL MEDICINE 2009; 2:16-21. [PMID: 20431704 PMCID: PMC2860750 DOI: 10.6030/1939-067x-2.1.16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Publication bias has been around for about 50 years. It has become a concern for almost 20 years in the medical research community. This review briefly summarizes the current status of publication bias, potential sources where bias may arise from, and its common evaluation methods. In the field of translational stroke research, publication bias has long been suspected; however, it has not been addressed with sufficient efforts. Its status has remained the same during the last decade. The author emphasizes the important role that publishers might play in addressing publication bias.
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Affiliation(s)
- Shimin Liu
- Department of Neurology, Mount Sinai School of Medicine, NYU
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115
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What is the translational efficacy of chemotherapeutic drug research in neuro-oncology? A systematic review and meta-analysis of the efficacy of BCNU and CCNU in animal models of glioma. J Neurooncol 2008; 91:117-25. [PMID: 18813876 DOI: 10.1007/s11060-008-9697-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 09/08/2008] [Indexed: 01/31/2023]
Abstract
INTRODUCTION The translational value of experimental therapeutic neuroscience research to clinical practice is highly variable. This has been particularly well demonstrated in the field of neuroprotective agents following either head injury or stroke. In this study we evaluate the efficacy of systemic BCNU and CCNU in experimental glioma models and how the experimental data has translated into clinical practice. METHODS A systematic review of the efficacy of BCNU and CCNU, against experimental rodent and murine in vivo glioma models was conducted. Selected articles were graded on a 15 point scale for scientific methodology. A stratified meta-analysis based on median-survival data and effect sizes was performed to generate global-efficacy estimates for BCNU and CCNU, and to produce 'weighted-mean effect-sizes' for individual sub-categories of selected study-characteristics. RESULTS Fourteen papers satisfied search criteria and encompassed 231 treatment comparisons in 2256 animals. The median methodology score was 9 (range 7-12/15). Global-efficacy estimates were BCNU 0.194 (95% CI -0.538 to 0.927) and CCNU 0.432 (95% CI -0.392 to 1.256), with CCNU being significantly more effective than BCNU. Because of these wide confidence intervals a beneficial or detrimental effect of either agent could not be confirmed. Most selected study-design characteristics (e.g. glioma cell line, drug dosage, drug scheduling, mode of drug administration, timing of therapy after glioma implantation but not animal used) significantly influenced the efficacy-results obtained. The methodological score did not influence efficacy-estimate. CONCLUSION This review has found (i) experimental-design influenced the efficacy-data obtained and (ii) that there is highly variable outcome data for the efficacy of both BCNU and CCNU in experimental in vivo rodent and murine glioma models. In many ways these findings are analagous to the use of nitrosoureas in human malignant glioma. The statistically significant small beneficial effect of nitrosoureas in combination with other chemotherapeutic agents in human glioma was only noted after a meta-analysis of human randomized controlled trials.
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116
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Macleod MR, Fisher M, O'Collins V, Sena ES, Dirnagl U, Bath PMW, Buchan A, van der Worp HB, Traystman R, Minematsu K, Donnan GA, Howells DW. Good laboratory practice: preventing introduction of bias at the bench. Stroke 2008; 40:e50-2. [PMID: 18703798 DOI: 10.1161/strokeaha.108.525386] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND PURPOSE As a research community, we have failed to demonstrate that drugs which show substantial efficacy in animal models of cerebral ischemia can also improve outcome in human stroke. Summary of Review- Accumulating evidence suggests this may be due, at least in part, to problems in the design, conduct and reporting of animal experiments which create a systematic bias resulting in the overstatement of neuroprotective efficacy. CONCLUSIONS Here, we set out a series of measures to reduce bias in the design, conduct and reporting of animal experiments modeling human stroke.
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117
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Wong M. Stabilizing dendritic structure as a novel therapeutic approach for epilepsy. Expert Rev Neurother 2008; 8:907-15. [PMID: 18505356 DOI: 10.1586/14737175.8.6.907] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
People with epilepsy often experience long-term cognitive dysfunction and other neurological deficits, including memory loss, learning disabilities and neurobehavioral disorders, which may exhibit a progressive course correlating with worsening seizure control. Furthermore, a third of epilepsy patients have seizures that are intractable to all available treatments. Thus, novel therapies for seizures and the neurological comorbidities of epilepsy are desperately needed. As most current treatments are merely symptomatic therapies that suppress seizures, epilepsy researchers have recently realized the critical need for novel therapeutic strategies targeting the underlying mechanisms of epileptogenesis and seizure-related brain injury. Yet, to date, few such antiepileptogenic therapies have emerged or are even in developmental stages. Although many seizure medications modulate the functional or physiological activity of neurons, the methods for stabilizing the structure of neurons are relatively unexplored therapeutic strategies for epilepsy. Human pathological studies and animal models of epilepsy demonstrate obvious structural abnormalities in dendrites of neurons, which could contribute to neuronal dysfunction, epileptogenesis and cognitive/neurological deficits in epilepsy patients. This dendritic injury may be caused by activity-dependent breakdown of cytoskeletal elements, such as actin. Mechanistically targeted approaches to limit seizure-related structural changes in dendrites may represent a novel therapeutic strategy for treating epilepsy and its complications.
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Affiliation(s)
- Michael Wong
- Department of Neurology, Box 8111, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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118
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Ford GA. Clinical pharmacological issues in the development of acute stroke therapies. Br J Pharmacol 2008; 153 Suppl 1:S112-9. [PMID: 18311155 DOI: 10.1038/sj.bjp.0707654] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The demonstration of the ischaemic penumbra in animal models and the effectiveness of reperfusion therapy in humans led to considerable optimism for neuroprotection in acute stroke. Initial experience with failure of phase II and III trials led to the STAIR recommendations for pre-clinical and clinical studies. Review of pre-clinical studies suggests that selection of agents for clinical development may not have been optimal. The neuroprotective agent NXY-059 fulfilled pre-clinical and many clinical STAIR criteria but a second large phase III study failed to demonstrate any benefit. Many of the STAIR criteria have not been fulfilled in the development of recent neuroprotective agents. Other issues not addressed include the use of animal models more reflective of older stroke patients with physiological derangement, demonstration of drug distribution to the proposed site of action in humans, selection of patients with salvageable tissue, achieving very early treatment, refinement of measurement of neurological impairment and disability, and physiological optimization in proof of concept human studies. Increasing the number and quality of clinical centres undertaking acute stroke research, use of surrogate imaging markers and adaptive dose designs in phase II trials could improve the likelihood of identifying an effective neuroprotective. Neuroprotection in acute stroke remains a significant challenge but has not been clearly shown to be ineffective. Given the profound burden of stroke and limited applicability of reperfusion to currently at best 10% patients, further proof of concept studies of neuroprotection remain indicated with careful review of pre-clinical data and more rigorous phase II trial design.
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Affiliation(s)
- G A Ford
- Clinical Research Centre, Newcastle University, Newcastle upon Tyne, UK.
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119
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Minnerup J, Heidrich J, Wellmann J, Rogalewski A, Schneider A, Schäbitz WR. Meta-analysis of the efficacy of granulocyte-colony stimulating factor in animal models of focal cerebral ischemia. Stroke 2008; 39:1855-61. [PMID: 18403735 DOI: 10.1161/strokeaha.107.506816] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Recent reports have described the efficacy of the hematopoietic growth factor granulocyte-colony stimulating factor (G-CSF) in animal stroke models. Early clinical multicenter trials evaluating the effect of G-CSF in acute stroke and pilot clinical trials for the subacute phase are ongoing. To guide further development, a meta-analysis was performed to assess the effects of G-CSF on infarct size and sensorimotor deficits. METHODS Using electronic and manual searches of the literature, we identified studies describing the efficacy of G-CSF in animal models of focal cerebral ischemia. Two reviewers independently selected studies and extracted data on study quality, G-CSF doses, time of administration, and outcome measured as infarct volume and/or sensorimotor deficit. Data from all studies were pooled by meta-regression analyses. RESULTS Thirteen studies including 277 animals for infarct size calculation and 258 animals for assessment of sensorimotor deficit met the criteria for inclusion. Overall efficacy of G-CSF regarding infarct size reduction was 42%. Meta-regression analysis revealed a 0.8% (P<0.0001) decrease in infarct size per 1-mug/kg increase in G-CSF dose when applied within the first 6 hours and a 2.1% (P<0.0001) decrease when applied later than 6 hours after induction of ischemia with a significant (P=0.0004) greater infarct size reduction after delayed treatment. Sensorimotor deficits categorized into 3 subgroups improved between 24% and 40%. CONCLUSIONS Our findings consolidate G-CSF as a drug that both reduces infarct size and enhances functional recovery. These effects are presumably dose dependent. In contrast to most other neuroprotectants, a beneficial outcome may also be achieved when treatment is delayed.
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Affiliation(s)
- Jens Minnerup
- Universitätsklinikum Münster, Klinik und Poliklinik für Neurologie, Albert-Schweitzer-Strasse 33, 48149 Münster, Germany.
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120
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Crossley NA, Sena E, Goehler J, Horn J, van der Worp B, Bath PM, Macleod M, Dirnagl U. Empirical Evidence of Bias in the Design of Experimental Stroke Studies. Stroke 2008; 39:929-34. [DOI: 10.1161/strokeaha.107.498725] [Citation(s) in RCA: 183] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
At least part of the failure in the transition from experimental to clinical studies in stroke has been attributed to the imprecision introduced by problems in the design of experimental stroke studies. Using a metaepidemiologic approach, we addressed the effect of randomization, blinding, and use of comorbid animals on the estimate of how effectively therapeutic interventions reduce infarct size.
Methods—
Electronic and manual searches were performed to identify meta-analyses that described interventions in experimental stroke. For each meta-analysis thus identified, a reanalysis was conducted to estimate the impact of various quality items on the estimate of efficacy, and these estimates were combined in a meta–meta-analysis to obtain a summary measure of the impact of the various design characteristics.
Results—
Thirteen meta-analyses that described outcomes in 15 635 animals were included. Studies that included unblinded induction of ischemia reported effect sizes 13.1% (95% CI, 26.4% to 0.2%) greater than studies that included blinding, and studies that included healthy animals instead of animals with comorbidities overstated the effect size by 11.5% (95% CI, 21.2% to 1.8%). No significant effect was found for randomization, blinded outcome assessment, or high aggregate CAMARADES quality score.
Conclusions—
We provide empirical evidence of bias in the design of studies, with studies that included unblinded induction of ischemia or healthy animals overestimating the effectiveness of the intervention. This bias could account for the failure in the transition from bench to bedside of stroke therapies.
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Affiliation(s)
- Nicolas A. Crossley
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
| | - Emily Sena
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
| | - Jos Goehler
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
| | - Jannekke Horn
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
| | - Bart van der Worp
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
| | - Philip M.W. Bath
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
| | - Malcolm Macleod
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
| | - Ulrich Dirnagl
- From the Center for Stroke Research (N.A.C., J.G., U.D.), Department of Experimental Neurology, Charité Universitätsmedizin, Berlin, Germany; the Department of Clinical Neurosciences (E.S., M.M.), University of Edinburgh, Edinburgh, Scotland; the Division of Stroke Medicine (P.M.W.B.), University of Nottingham, Nottingham, England; the Department of Intensive Care (J.H.), Academical Medical Center, Amsterdam, The Netherlands; and the Department of Neurology (B.v.d.W.), Rudolf Magnus Institute of
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Affiliation(s)
- Geoffrey A. Donnan
- From the National Stroke Research Institute, Austin Health, University of Melbourne, Heidelberg Heights, Australia
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122
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Experimental models, neurovascular mechanisms and translational issues in stroke research. Br J Pharmacol 2007; 153 Suppl 1:S396-405. [PMID: 18157168 DOI: 10.1038/sj.bjp.0707626] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Numerous failures in clinical stroke trials have led to some pessimism in the field. This short review examines the following questions: Can experimental models of stroke be validated? How can combination stroke therapies be productively pursued? Can we achieve neuroprotection without reperfusion? And finally, can we move from a pure neurobiology view of stroke towards a more integrative approach targeting all cell types within the entire neurovascular unit? Emerging data from both experimental models and clinical findings suggest that neurovascular mechanisms may provide new opportunities for treating stroke. Ultimately, both bench-to-bedside and bedside-back-to-bench interactions may be required to overcome the translational hurdles for this challenging disease.
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123
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Knight A. Systematic Reviews of Animal Experiments Demonstrate Poor Human Clinical and Toxicological Utility. Altern Lab Anim 2007; 35:641-59. [DOI: 10.1177/026119290703500610] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The assumption that animal models are reasonably predictive of human outcomes provides the basis for their widespread use in toxicity testing and in biomedical research aimed at developing cures for human diseases. To investigate the validity of this assumption, the comprehensive Scopus biomedical bibliographic databases were searched for published systematic reviews of the human clinical or toxicological utility of animal experiments. In 20 reviews in which clinical utility was examined, the authors concluded that animal models were either significantly useful in contributing to the development of clinical interventions, or were substantially consistent with clinical outcomes, in only two cases, one of which was contentious. These included reviews of the clinical utility of experiments expected by ethics committees to lead to medical advances, of highly-cited experiments published in major journals, and of chimpanzee experiments — those involving the species considered most likely to be predictive of human outcomes. Seven additional reviews failed to clearly demonstrate utility in predicting human toxicological outcomes, such as carcinogenicity and teratogenicity. Consequently, animal data may not generally be assumed to be substantially useful for these purposes. Possible causes include interspecies differences, the distortion of outcomes arising from experimental environments and protocols, and the poor methodological quality of many animal experiments, which was evident in at least 11 reviews. No reviews existed in which the majority of animal experiments were of good methodological quality. Whilst the effects of some of these problems might be minimised with concerted effort (given their widespread prevalence), the limitations resulting from interspecies differences are likely to be technically and theoretically impossible to overcome. Non-animal models are generally required to pass formal scientific validation prior to their regulatory acceptance. In contrast, animal models are simply assumed to be predictive of human outcomes. These results demonstrate the invalidity of such assumptions. The consistent application of formal validation studies to all test models is clearly warranted, regardless of their animal, non-animal, historical, contemporary or possible future status. Likely benefits would include, the greater selection of models truly predictive of human outcomes, increased safety of people exposed to chemicals that have passed toxicity tests, increased efficiency during the development of human pharmaceuticals and other therapeutic interventions, and decreased wastage of animal, personnel and financial resources. The poor human clinical and toxicological utility of most animal models for which data exists, in conjunction with their generally substantial animal welfare and economic costs, justify a ban on animal models lacking scientific data clearly establishing their human predictivity or utility.
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Wheble PC, Sena ES, Macleod MR. A Systematic Review and Meta-Analysis of the Efficacy of Piracetam and Piracetam-Like Compounds in Experimental Stroke. Cerebrovasc Dis 2007; 25:5-11. [DOI: 10.1159/000111493] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Accepted: 07/29/2007] [Indexed: 11/19/2022] Open
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125
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Sena E, van der Worp HB, Howells D, Macleod M. How can we improve the pre-clinical development of drugs for stroke? Trends Neurosci 2007; 30:433-9. [PMID: 17765332 DOI: 10.1016/j.tins.2007.06.009] [Citation(s) in RCA: 271] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 06/15/2007] [Accepted: 06/18/2007] [Indexed: 01/13/2023]
Abstract
The development of stroke drugs has been characterized by success in animal studies and subsequent failure in clinical trials. Animal studies might have overstated efficacy, or clinical trials might have understated efficacy; in either case we need to better understand the reasons for failure. Techniques borrowed from clinical trials have recently allowed the impact of publication and study-quality biases on published estimates of efficacy in animal experiments to be described. On the basis of these data, we propose minimum standards for the range and quality of pre-clinical animal data. We believe the adoption of these standards will lead to improved effectiveness and efficiency in the selection of drugs for clinical trials in stroke and in the design of those trials.
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Affiliation(s)
- Emily Sena
- Department of Clinical Neurosciences, University of Edinburgh, UK
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126
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Okubo S, Igarashi H, Kanamatsu T, Hasegawa D, Orima H, Katayama Y. FK-506 extended the therapeutic time window for thrombolysis without increasing the risk of hemorrhagic transformation in an embolic rat stroke model. Brain Res 2007; 1143:221-7. [PMID: 17316578 DOI: 10.1016/j.brainres.2007.01.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 01/17/2007] [Accepted: 01/18/2007] [Indexed: 11/30/2022]
Abstract
FK-506 confers a neuroprotective effect and is thought to extend the time window for thrombolytic treatment of cerebral ischemia. These effects have not been assessed in an embolic stroke model. In addition, clinical studies have raised concern that FK-506 may increase the risk of hemorrhagic transformation by damaging vascular endothelial cells. We investigated whether combined administration of recombinant tissue plasminogen activator (rt-PA) and FK-506 would extend the therapeutic time window without increasing the hemorrhagic transformation in a rat embolic stroke model. Male Sprague-Dawley rats (n=66) were subjected to embolic infarction and assigned into eight groups. Six of the groups were treated with or without FK-506 (0.3 mg/kg) administration at 60 min after embolization, together with and all six groups received systemic rt-PA administration (10 mg/kg) at 60, 90, or 120 min. Two permanent ischemia groups were administered saline either with or without FK-506. Infarct and hemorrhagic volume were assessed at 24 h after embolization. Diffusion-weighted and perfusion-weighted magnetic resonance imaging (MRI) were performed in the groups administered rt-PA at 90 min and a vehicle control group to assess whether FK-506 influenced the effectiveness of MRI in revealing ischemic lesion. FK-506 extended the therapeutic time window for systemic thrombolysis compared to rt-PA alone without increasing the risk for hemorrhage. Combined therapy with FK-506 salvaged some of the MRI, revealing ischemic lesions destined to infarction in the animals treated by rt-PA alone. Single low dose of FK-506 alone did not ameliorate the embolic infarction, but it did prove effective in extending the therapeutic time windows for thrombolysis without increasing the risk of hemorrhagic transformation.
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Affiliation(s)
- Seiji Okubo
- Division of Neurology, Nephrology and Rheumatology, Department of Internal Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
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127
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Abstract
Poor methodological standards in animal studies mean that positive results rarely translate to the clinical domain
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Affiliation(s)
- Daniel G Hackam
- Cardiac Rehabilitation and Secondary Prevention Program, Toronto, ON, Canada M4G 1R7
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128
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Sena E, Wheble P, Sandercock P, Macleod M. Systematic review and meta-analysis of the efficacy of tirilazad in experimental stroke. Stroke 2007; 38:388-94. [PMID: 17204689 DOI: 10.1161/01.str.0000254462.75851.22] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND AND PURPOSE Tirilazad is a candidate neuroprotective drug with reported efficacy in animal models of stroke that was, however, without benefit in clinical trials. This apparent contradiction might be explained if the animal studies were falsely positive, if the clinical trials were falsely negative, or if tirilazad was not tested under the same conditions in animal and clinical studies. Here we use systematic review and meta-analysis to describe the characteristics and limits to the neuroprotective action of tirilazad in animal models of stroke. METHODS Systematic review and meta-analysis of studies describing the efficacy of tirilazad in animal models of focal ischemia, in which outcome was measured as infarct volume and/or neurological score. Weighted mean difference random effects meta-analysis was used to measure overall efficacy in prespecified subgroups. RESULTS Eighteen studies describing outcome in 544 animals were identified. Study quality (median score, 5/10; interquartile range, 4 to 6) was similar to that seen in systematic reviews of other candidate neuroprotective drugs. Tirilazad reduced infarct volume by 29.2% (95% confidence interval 21.1% to 37.2%) and improved neurobehavioral score by 48.1% (95% confidence interval 29.3% to 66.9%). CONCLUSIONS Tirilazad may have substantial efficacy in animal models of stroke, but this conclusion must be qualified because of the presence of potential sources of bias.
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Affiliation(s)
- Emily Sena
- Clinical Neurosciences, University of Edinburgh, Edinburgh, Scotland, UK
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129
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Abstract
Over the past decades, great progress has been made in clinical as well as experimental stroke research. Disappointingly, however, hundreds of clinical trials testing neuroprotective agents have failed despite efficacy in experimental models. Recently, several systematic reviews have exposed a number of important deficits in the quality of preclinical stroke research. Many of the issues raised in these reviews are not specific to experimental stroke research, but apply to studies of animal models of disease in general. It is the aim of this article to review some quality-related sources of bias with a particular focus on experimental stroke research. Weaknesses discussed include, among others, low statistical power and hence reproducibility, defects in statistical analysis, lack of blinding and randomization, lack of quality-control mechanisms, deficiencies in reporting, and negative publication bias. Although quantitative evidence for quality problems at present is restricted to preclinical stroke research, to spur discussion and in the hope that they will be exposed to meta-analysis in the near future, I have also included some quality-related sources of bias, which have not been systematically studied. Importantly, these may be also relevant to mechanism-driven basic stroke research. I propose that by a number of rather simple measures reproducibility of experimental results, as well as the step from bench to bedside in stroke research may be made more successful. However, the ultimate proof for this has to await successful phase III stroke trials, which were built on basic research conforming to the criteria as put forward in this article.
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Affiliation(s)
- Ulrich Dirnagl
- Department of Experimental Neurology, Center for Stroke Research, Humboldt-Universität Berlin, Universitätsklinikum Charite, Berlin, Germany.
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130
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Abstract
The credibility and replication of research findings evolve over time, as data accumulate. However, translation of postulated research promises to real-life biomedical applications is uncommon. In some fields of research, we may observe diminishing effects for the strength of research findings and rapid alternations of exaggerated claims and extreme contradictions--the "Proteus Phenomenon." While these phenomena are probably more prominent in the basic sciences, similar manifestations have been documented even in clinical trials and they may undermine the credibility of clinical research. Significance-chasing bias may be in part responsible, but the greatest threat may come from the poor relevance and scientific rationale and thus low pre-study odds of success of research efforts. Given that we currently have too many research findings, often with low credibility, replication and rigorous evaluation become as important as or even more important than discovery. Credibility, replication, and translation are all desirable properties of research findings, but are only modestly correlated. In this essay, I discuss some of the evidence (or lack thereof) for the process of evolution and translation of research findings, with emphasis on the biomedical sciences.
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Affiliation(s)
- John P A Ioannidis
- Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece.
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131
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Gibson CL, Gray LJ, Murphy SP, Bath PMW. Estrogens and experimental ischemic stroke: a systematic review. J Cereb Blood Flow Metab 2006; 26:1103-13. [PMID: 16437060 DOI: 10.1038/sj.jcbfm.9600270] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Estrogens are believed to provide females with endogenous protection against cerebrovascular events although clinical trials studying long-term hormone replacement have yielded disappointing results. In contrast, estrogens might be neuroprotective after experimental ischemia. We performed a systematic review of controlled experimental studies that administered estrogens before, or after, cerebral ischemia and measured lesion volume. Relevant studies were found from searching PubMed, Embase and Web of Science. From 161 identified publications, 27 studies using 1,304 experimental subjects were analyzed using the Cochrane Review Manager software. Estrogens reduced lesion volume in a dose-dependent manner, after either transient (P<0.001) or permanent (P<0.001) ischemia and whether administered before or up to 4 h after ischemia onset; no studies assessed efficacy for later time periods. The effect size for estrogens decreased with increasing quality scores for studies of transient ischemia. Estrogens reduced lesion volume when administered to ovariectomized females and young adult males, but had no effect in intact females. Limited data were present for aged animals and the full dose-response relationship was not available in all experimental groups. On the basis of these data, estrogens are a candidate treatment for ischemic stroke, although further preclinical studies are also warranted.
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Affiliation(s)
- Claire L Gibson
- Institute of Cell Signalling, Queen's Medical Centre, University of Nottingham, Nottingham, UK.
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132
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Ross AP, Drew KL. Potential for discovery of neuroprotective factors in serum and tissue from hibernating species. Mini Rev Med Chem 2006; 6:875-84. [PMID: 16918494 PMCID: PMC4454377 DOI: 10.2174/138955706777934964] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hibernation is a unique phenotype displayed by a phylogenetically diverse group of organisms including several species of mammals and one species of primate. Here we review evidence for blood and tissue borne signaling molecules in hibernating animals, achievements in isolating and characterizing these molecules, and potential medicinal applications.
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Affiliation(s)
- Austin P. Ross
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Kelly L. Drew
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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O'Collins VE, Macleod MR, Donnan GA, Horky LL, van der Worp BH, Howells DW. 1,026 experimental treatments in acute stroke. Ann Neurol 2006; 59:467-77. [PMID: 16453316 DOI: 10.1002/ana.20741] [Citation(s) in RCA: 980] [Impact Index Per Article: 54.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Preclinical evaluation of neuroprotectants fostered high expectations of clinical efficacy. When not matched, the question arises whether experiments are poor indicators of clinical outcome or whether the best drugs were not taken forward to clinical trial. Therefore, we endeavored to contrast experimental efficacy and scope of testing of drugs used clinically and those tested only experimentally. METHODS We identified neuroprotectants and reports of experimental efficacy via a systematic search. Controlled in vivo and in vitro experiments using functional or histological end points were selected for analysis. Relationships between outcome, drug mechanism, scope of testing, and clinical trial status were assessed statistically. RESULTS There was no evidence that drugs used clinically (114 drugs) were more effective experimentally than those tested only in animal models (912 drugs), for example, improvement in focal models averaged 31.3 +/- 16.7% versus 24.4 +/- 32.9%, p > 0.05, respectively. Scope of testing using Stroke Therapy Academic Industry Roundtable (STAIR) criteria was highly variable, and no relationship was found between mechanism and efficacy. INTERPRETATION The results question whether the most efficacious drugs are being selected for stroke clinical trials. This may partially explain the slow progress in developing treatments. Greater rigor in the conduct, reporting, and analysis of animal data will improve the transition of scientific advances from bench to bedside.
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Affiliation(s)
- Victoria E O'Collins
- Neuroscience Lab, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia
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134
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Sheehan J, Eischeid A, Saunders R, Pouratian N. Potentiation of neurite outgrowth and reduction of apoptosis by immunosuppressive agents: implications for neuronal injury and transplantation. Neurosurg Focus 2006; 20:E9. [PMID: 16711666 DOI: 10.3171/foc.2006.20.5.10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Immunosuppressive agents are believed to play a role in recovery from spinal cord injury, but the underlying mechanisms by which neuronal function is improved by these agents are poorly understood. In this study, the authors evaluate the effect of immunosuppressive medications on neurite outgrowth and cell survival after a pharmacologically induced injury.
Methods
Differentiated human neuroblastoma SH-SY5Y cells were injured using the calcium agonist thapsigargin. After cellular injury, neurite outgrowth in the presence or absence of immunosuppressive agents was measured. Apoptosis was quantified with the aid of a terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling assay.
Neurite outgrowth was severely restricted following thapsigargin injury. Outgrowth was potentiated, however, by the addition of concentrations of 1 and 10 μM cyclosporin A in a dose-dependent fashion. Similarly, addition of 10 nM FK506 increased the percentage of neurites in the 20- to 40-micron range. A low dose (1 μM) of dexamethasone did not have a significant effect on neurite outgrowth, but a higher dose (10 μM) increased the percentage of neurites in the 10- to 45-micron range. These agents also lessened the degree of thapsigargin-induced apoptosis.
Conclusions
Immunosuppressive agents such as cyclosporin A, FK506, and dexamethasone can potentiate neurite outgrowth and protect against apoptotic cell death in a human postmitotic neuronal cell line. Such effects may have implications for lessening neuronal injury after neurotrauma, stroke, or neurodegeneration.
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Affiliation(s)
- Jason Sheehan
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia 22908, USA.
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135
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Ikeda Y, Miura T, Sakamoto J, Miki T, Tanno M, Kobayashi H, Ohori K, Takahashi A, Shimamoto K. Activation of ERK and suppression of calcineurin are interacting mechanisms of cardioprotection afforded by δ-opioid receptor activation. Basic Res Cardiol 2006; 101:418-26. [PMID: 16619106 DOI: 10.1007/s00395-006-0595-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Accepted: 03/07/2006] [Indexed: 11/26/2022]
Abstract
The aim of this study was to examine possible interactions of ERK and calcineurin in cardioprotection afforded by delta-opioid receptor stimulation. Infarction was induced in rat hearts by 20-min coronary occlusion and reperfusion. Tissue ERK level and calcienurin activity were determined by immunoblotting and an assay using a phosphopeptide substrate, respectively. Administration of a delta-opioid receptor agonist, D-Ala2-D-Leu5-enkephalin (DADLE, 1 mg/kg), before ischemia increased the phospho-ERK levels during ischemia and reduced infarct size (as percentage of risk area, %IS/AR) from 47.7 +/- 2.3% to 23.2 +/- 2.5%. This protection was abolished by 10 mg/kg of natrindole hydrochloride (NTI), a delta-opioid receptor antagonist. PD98059, a MEK1/2 inhibitor, abolished both ERK1/2 activation and infarct size limitation by DADLE. Calcineurin inhibitors, cyclosporine-A (5 mg/kg) and FK506 (3.5 mg/kg), reduced %IS/AR (27.4 +/- 4.4% and 29.9 +/- 3.4%, respectively). The protective effects of these calcineurin inhibitors were inhibited by PD98059, and the combination of DADLE with cyclosporine-A or FK506 did not afford further cardioprotection. DADLE significantly suppressed myocardial calcineurin activity, and this effect was inhibited by NTI. Suppression of calcineurin activity by FK506 was associated with modest activation of ERK1/2. These results suggest that suppression of calcineurin and activation of ERK1/2 are interacting mechanisms involved in cardioprotection by delta-opioid receptor activation.
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Affiliation(s)
- Yoshihiro Ikeda
- Second Department of Internal Medicine, Sapporo Medical University School of Medicine, South-1 West-16, Chuo-ku, Sapporo, 060-8543, Japan
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136
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Labrande C, Velly L, Canolle B, Guillet B, Masmejean F, Nieoullon A, Pisano P. Neuroprotective effects of tacrolimus (FK506) in a model of ischemic cortical cell cultures: role of glutamate uptake and FK506 binding protein 12 kDa. Neuroscience 2005; 137:231-9. [PMID: 16289353 DOI: 10.1016/j.neuroscience.2005.08.080] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Revised: 08/29/2005] [Accepted: 08/31/2005] [Indexed: 11/16/2022]
Abstract
BACKGROUND The mechanisms underlying the neuroprotective effects of the immunosuppressant tacrolimus, observed in vivo, remain unclear. Here we quantify these effects in vitro, and evaluate the potential involvement of the glutamate and/or immunophilin FK506 binding protein 12 kDa in tacrolimus-induced neuroprotection. METHODS Primary cultures of neurons and astrocytes from rat cerebral cortex were subjected to transient oxygen-glucose deprivation. Neuronal injury was evaluated by cell counting after immunostaining experiments, lactate dehydrogenase release and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction. The involvement of the immunophilin FK506 binding protein 12 kDa was explored using an anti-FK506 binding protein 12 kDa antibody, (3-3-pyridyl)-1-propyl(2 s)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidine carboxylate and rapamycin. Extracellular glutamate and glutamate uptake were respectively measured by high performance liquid chromatography and l-[3H]glutamate incorporation. RESULTS When added during either oxygen-glucose deprivation or reoxygenation, FK506 (50-500 pM) offered significant neuroprotection. During oxygen-glucose deprivation, it was able to reverse the oxygen-glucose deprivation-induced increase in extracellular glutamate and decrease in glutamate uptake and this effect was reversed in the presence of threo-3-methyl glutamate, a specific inhibitor of glutamate transporter-1. Blocking FK506 binding protein 12 kDa inhibited the neuroprotection induced by tacrolimus added during either oxygen-glucose deprivation or reoxygenation. Tacrolimus-induced neuroprotection was also reversed in the presence of rapamycin, an immunosuppressant FK506 binding protein 12 kDa ligand devoid of neuroprotective properties and (3-3-pyridyl)-1-propyl(2 s)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidine carboxylate, a non-immunosuppressant ligand of FK506 binding protein 12 kDa, exerteing neuroprotective effects. CONCLUSION The beneficial effects of tacrolimus during in vitro ischemia/reperfusion seem to indicate the restoration of a glutamate transporter-1-mediated activity and could be mediated by a FK506 binding protein 12 kDa pathway.
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Affiliation(s)
- C Labrande
- Laboratoire de Pharmacodynamie, Faculté de Pharmacie, Université de la Méditerranée, Marseille, France
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Macleod MR, Ebrahim S, Roberts I. Surveying the literature from animal experiments: systematic review and meta-analysis are important contributions. BMJ 2005; 331:110. [PMID: 16002897 PMCID: PMC558663 DOI: 10.1136/bmj.331.7508.110-b] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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