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Sarkar A, Kim KT, Tsymbalyuk O, Keledjian K, Wilhelmy BE, Sherani NA, Jia X, Gerzanich V, Simard JM. A Direct Comparison of Physical Versus Dihydrocapsaicin-Induced Hypothermia in a Rat Model of Traumatic Spinal Cord Injury. Ther Hypothermia Temp Manag 2022; 12:90-102. [PMID: 35675523 PMCID: PMC9231662 DOI: 10.1089/ther.2021.0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating neurological condition with no effective treatment. Hypothermia induced by physical means (cold fluid) is established as an effective therapy in animal models of SCI, but its clinical translation to humans is hampered by several constraints. Hypothermia induced pharmacologically may be noninferior or superior to physically induced hypothermia for rapid, convenient systemic temperature reduction, but it has not been investigated previously in animal models of SCI. We used a rat model of SCI to compare outcomes in three groups: (1) normothermic controls; (2) hypothermia induced by conventional physical means; (3) hypothermia induced by intravenous (IV) dihydrocapsaicin (DHC). Male rats underwent unilateral lower cervical SCI and were treated after a 4-hour delay with physical cooling or IV DHC (∼0.60 mg/kg total) cooling (both 33.0 ± 1.0°C) lasting 4 hours; controls were kept normothermic. Telemetry was used to monitor temperature and heart rate during and after treatments. In two separate experiments, one ending at 48 hours, the other at 6 weeks, “blinded” investigators evaluated rats in the three groups for neurological function followed by histopathological evaluation of spinal cord tissues. DHC reliably induced systemic cooling to 32–33°C. At both the time points examined, the two modes of hypothermia yielded similar improvements in neurological function and lesion size compared with normothermic controls. Our results indicate that DHC-induced hypothermia may be comparable with physical hypothermia in efficacy, but more clinically feasible to administer than physical hypothermia.
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Affiliation(s)
- Amrita Sarkar
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kevin T Kim
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Orest Tsymbalyuk
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kaspar Keledjian
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Bradley E Wilhelmy
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Nageen A Sherani
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - J Marc Simard
- Department of Neurosurgery, Pathology and Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Chen S, Lachance BB, Gao L, Jia X. Targeted temperature management and early neuro-prognostication after cardiac arrest. J Cereb Blood Flow Metab 2021; 41:1193-1209. [PMID: 33444088 PMCID: PMC8142127 DOI: 10.1177/0271678x20970059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Targeted temperature management (TTM) is a recommended neuroprotective intervention for coma after out-of-hospital cardiac arrest (OHCA). However, controversies exist concerning the proper implementation and overall efficacy of post-CA TTM, particularly related to optimal timing and depth of TTM and cooling methods. A review of the literature finds that optimizing and individualizing TTM remains an open question requiring further clinical investigation. This paper will summarize the preclinical and clinical trial data to-date, current recommendations, and future directions of this therapy, including new cooling methods under investigation. For now, early induction, maintenance for at least 24 hours, and slow rewarming utilizing endovascular methods may be preferred. Moreover, timely and accurate neuro-prognostication is valuable for guiding ethical and cost-effective management of post-CA coma. Current evidence for early neuro-prognostication after TTM suggests that a combination of initial prediction models, biomarkers, neuroimaging, and electrophysiological methods is the optimal strategy in predicting neurological functional outcomes.
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Affiliation(s)
- Songyu Chen
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Brittany Bolduc Lachance
- Program in Trauma, Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Liang Gao
- Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Dietrich WD, Bramlett HM. Therapeutic hypothermia and targeted temperature management for traumatic brain injury: Experimental and clinical experience. Brain Circ 2017; 3:186-198. [PMID: 30276324 PMCID: PMC6057704 DOI: 10.4103/bc.bc_28_17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 11/20/2017] [Accepted: 11/24/2017] [Indexed: 12/21/2022] Open
Abstract
Traumatic brain injury (TBI) is a worldwide medical problem, and currently, there are few therapeutic interventions that can protect the brain and improve functional outcomes in patients. Over the last several decades, experimental studies have investigated the pathophysiology of TBI and tested various pharmacological treatment interventions targeting specific mechanisms of secondary damage. Although many preclinical treatment studies have been encouraging, there remains a lack of successful translation to the clinic and no therapeutic treatments have shown benefit in phase 3 multicenter trials. Therapeutic hypothermia and targeted temperature management protocols over the last several decades have demonstrated successful reduction of secondary injury mechanisms and, in some selective cases, improved outcomes in specific TBI patient populations. However, the benefits of therapeutic hypothermia have not been demonstrated in multicenter randomized trials to significantly improve neurological outcomes. Although the exact reasons underlying the inability to translate therapeutic hypothermia into a larger clinical population are unknown, this failure may reflect the suboptimal use of this potentially powerful therapeutic in potentially treatable severe trauma patients. It is known that multiple factors including patient recruitment, clinical treatment variables, and cooling methodologies are all important in yielding beneficial effects. High-quality multicenter randomized controlled trials that incorporate these factors are required to maximize the benefits of this experimental therapy. This article therefore summarizes several factors that are important in enhancing the beneficial effects of therapeutic hypothermia in TBI. The current failures of hypothermic TBI clinical trials in terms of clinical protocol design, patient section, and other considerations are discussed and future directions are emphasized.
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Affiliation(s)
- W Dalton Dietrich
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Helen M Bramlett
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
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Simard JM, Jia X, Gerzanich V. Pharmacological induced target temperature management after cardiac arrest: the capsaicinoids. Neural Regen Res 2017; 12:1623-1624. [PMID: 29171426 PMCID: PMC5696842 DOI: 10.4103/1673-5374.217334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD; Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
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