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Jutzeler CR, Bourguignon L, Tong B, Ronca E, Bailey E, Harel NY, Geisler F, Ferguson AR, Kwon BK, Cragg JJ, Grassner L, Kramer JLK. Pharmacological management of acute spinal cord injury: a longitudinal multi-cohort observational study. Sci Rep 2023; 13:5434. [PMID: 37012257 PMCID: PMC10070428 DOI: 10.1038/s41598-023-31773-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 03/16/2023] [Indexed: 04/05/2023] Open
Abstract
Multiple types and classes of medications are administered in the acute management of traumatic spinal cord injury. Prior clinical studies and evidence from animal models suggest that several of these medications could modify (i.e., enhance or impede) neurological recovery. We aimed to systematically determine the types of medications commonly administered, alone or in combination, in the transition from acute to subacute spinal cord injury. For that purpose, type, class, dosage, timing, and reason for administration were extracted from two large spinal cord injury datasets. Descriptive statistics were used to describe the medications administered within the first 60 days after spinal cord injury. Across 2040 individuals with spinal cord injury, 775 unique medications were administered within the two months after injury. On average, patients enrolled in a clinical trial were administered 9.9 ± 4.9 (range 0-34), 14.3 ± 6.3 (range 1-40), 18.6 ± 8.2 (range 0-58), and 21.5 ± 9.7 (range 0-59) medications within the first 7, 14, 30, and 60 days post-injury, respectively. Those enrolled in an observational study were administered on average 1.7 ± 1.7 (range 0-11), 3.7 ± 3.7 (range 0-24), 8.5 ± 6.3 (range 0-42), and 13.5 ± 8.3 (range 0-52) medications within the first 7, 14, 30, and 60 days post-injury, respectively. Polypharmacy was commonplace (up to 43 medications per day per patient). Approximately 10% of medications were administered acutely as prophylaxis (e.g., against the development of pain or infections). To our knowledge, this was the first time acute pharmacological practices have been comprehensively examined after spinal cord injury. Our study revealed a high degree of polypharmacy in the acute stages of spinal cord injury, raising the potential to impact neurological recovery. All results can be interactively explored on the RXSCI web site ( https://jutzelec.shinyapps.io/RxSCI/ ) and GitHub repository ( https://github.com/jutzca/Acute-Pharmacological-Treatment-in-SCI/ ).
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Affiliation(s)
- Catherine R Jutzeler
- Department of Health Sciences and Technology, ETH Zurich, Lengghalde 2, 8008, Zurich, Switzerland.
| | - Lucie Bourguignon
- Department of Health Sciences and Technology, ETH Zurich, Lengghalde 2, 8008, Zurich, Switzerland
| | - Bobo Tong
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
| | - Elias Ronca
- Swiss Paraplegic Research, Nottwil, Switzerland
| | - Eric Bailey
- James J Peters Veterans Affairs Medical Center, Bronx, NY, USA
| | - Noam Y Harel
- James J Peters Veterans Affairs Medical Center, Bronx, NY, USA
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Fred Geisler
- University of Saskatchewan, Saskatoon, SK, Canada
| | - Adam R Ferguson
- Brain and Spinal Injury Center, Weill Institute for Neurosciences, University of California San Francisco (UCSF), San Francisco, CA, USA
- San Francisco Veteran's Affairs Health Care System, San Francisco, CA, USA
| | - Brian K Kwon
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
| | - Jacquelyn J Cragg
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Lukas Grassner
- Department of Neurosurgery, Medical University Innsbruck, Innsbruck, Austria
- Institute of Molecular Regenerative Medicine, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - John L K Kramer
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
- Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Hugill Centre for Anesthesia, University of British Columbia, Vancouver, Canada
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Scholpa NE, Schnellmann RG. Mitochondrial-Based Therapeutics for the Treatment of Spinal Cord Injury: Mitochondrial Biogenesis as a Potential Pharmacological Target. J Pharmacol Exp Ther 2017; 363:303-313. [PMID: 28935700 PMCID: PMC5676296 DOI: 10.1124/jpet.117.244806] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 09/20/2017] [Indexed: 12/24/2022] Open
Abstract
Spinal cord injury (SCI) is characterized by an initial trauma followed by a progressive cascade of damage referred to as secondary injury. A hallmark of secondary injury is vascular disruption leading to vasoconstriction and decreased oxygen delivery, which directly reduces the ability of mitochondria to maintain homeostasis and leads to loss of ATP-dependent cellular functions, calcium overload, excitotoxicity, and oxidative stress, further exacerbating injury. Restoration of mitochondria dysfunction during the acute phases of secondary injury after SCI represents a potentially effective therapeutic strategy. This review discusses the past and present pharmacological options for the treatment of SCI as well as current research on mitochondria-targeted approaches. Increased antioxidant activity, inhibition of the mitochondrial permeability transition, alternate energy sources, and manipulation of mitochondrial morphology are among the strategies under investigation. Unfortunately, many of these tactics address single aspects of mitochondrial dysfunction, ultimately proving largely ineffective. Therefore, this review also examines the unexplored therapeutic efficacy of pharmacological enhancement of mitochondrial biogenesis, which has the potential to more comprehensively improve mitochondrial function after SCI.
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Affiliation(s)
- Natalie E Scholpa
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (N.E.S., R.G.S.); and Southern Arizona VA Health Care System, Tucson, Arizona (R.G.S.)
| | - Rick G Schnellmann
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (N.E.S., R.G.S.); and Southern Arizona VA Health Care System, Tucson, Arizona (R.G.S.)
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Springer JE, Visavadiya NP, Sullivan PG, Hall ED. Post-Injury Treatment with NIM811 Promotes Recovery of Function in Adult Female Rats after Spinal Cord Contusion: A Dose-Response Study. J Neurotrauma 2017; 35:492-499. [PMID: 28967329 DOI: 10.1089/neu.2017.5167] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mitochondrial homeostasis is essential for maintaining cellular function and survival in the central nervous system (CNS). Mitochondrial function is significantly compromised after spinal cord injury (SCI) and is associated with accumulation of high levels of calcium, increased production of free radicals, oxidative damage, and eventually mitochondrial permeability transition (mPT). The formation of the mPT pore (mPTP) and subsequent mPT state are considered to be end stage events in the decline of mitochondrial integrity, and strategies that inhibit mPT can limit mitochondrial demise. Cyclosporine A (CsA) is thought to inhibit mPT by binding to cyclophilin D and has been shown to be effective in models of CNS injury. CsA, however, also inhibits calcineurin, which is responsible for its immunosuppressive properties. In the present study, we conducted a dose-response examination of NIM811, a nonimmunosuppressive CsA analog, on recovery of function and tissue sparing in a rat model of moderate to severe SCI. The results of our experiments revealed that NIM811 (10 mg/kg) significantly improved open field locomotor performance, while the two higher doses tested (20 and 40 mg/kg) significantly improved return of reflexive bladder control and significantly decreased the rostral-caudal extent of the lesion. Taken together, these results demonstrate the ability of NIM811 to improve recovery of function in SCI and support the role of protecting mitochondrial function as a potential therapeutic target.
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Affiliation(s)
- Joe E Springer
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, University of Kentucky Medical Center , Lexington, Kentucky
| | - Nishant P Visavadiya
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, University of Kentucky Medical Center , Lexington, Kentucky
| | - Patrick G Sullivan
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, University of Kentucky Medical Center , Lexington, Kentucky
| | - Edward D Hall
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, University of Kentucky Medical Center , Lexington, Kentucky
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Handreck A, Mall EM, Elger DA, Gey L, Gernert M. Different preparations, doses, and treatment regimens of cyclosporine A cause adverse effects but no robust changes in seizure thresholds in rats. Epilepsy Res 2015; 112:1-17. [DOI: 10.1016/j.eplepsyres.2015.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/27/2014] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
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Chow DSL, Teng Y, Toups EG, Aarabi B, Harrop JS, Shaffrey CI, Johnson MM, Boakye M, Frankowski RF, Fehlings MG, Grossman RG. Pharmacology of riluzole in acute spinal cord injury. J Neurosurg Spine 2013; 17:129-40. [PMID: 22985379 DOI: 10.3171/2012.5.aospine12112] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The aim of this paper was to characterize individual and population pharmacokinetics of enterally administered riluzole in a Phase 1 clinical trial of riluzole as a neuroprotective agent in adults 18-70 years old with acute spinal cord injury (SCI). METHODS Thirty-five individuals with acute SCI, American Spinal Injury Association Impairment Scale Grades A-C, neurological levels from C-4 to T-12, who were enrolled in the Phase 1 clinical trial sponsored by the North American Clinical Trials Network for Treatment of Spinal Cord Injury, received 50 mg riluzole twice daily for 28 doses. The first dose was administered at a mean of 8.7 ± 2.2 hours postinjury. Trough plasma samples were collected within 1 hour predose, and peak plasma samples were collected 2 hours postdose on Days 3 and 14 of treatment. Riluzole concentrations were quantified by high-performance liquid chromatography assay. The data were analyzed for individual and population pharmacokinetics using basic structural and covariate models. The pharmacokinetic measures studied were the peak concentration (C(max)), trough concentration (C(min)), systemic exposure (AUC(0-12)), clearance (CL/F), and volume of distribution (V_F) normalized by the bioavailability (F). RESULTS The C(max) and AUC(0-12) achieved in SCI patients were lower than those in ALS patients on the same dose basis, due to a higher CL and larger V. The pharmacokinetics of riluzole (C(max), C(min), AUC(0-12), CL, and V) changed during the acute and subacute phases of SCI during the 14 days of therapy. It was consistently observed in patients at all clinical sites that C(max), C(min), and AUC(0-12) (128.9 ng/ml, 45.6 ng/ml, and 982.0 ng × hr/ml, respectively) were significantly higher on Day 3 than on Day 14 (76.5 ng/ml, 19.1 ng/ml, and 521.0 ng × hr/ml, respectively). These changes resulted from lower CL (49.5 vs 106.2 L/hour) and smaller V (557.1 vs 1297.9/L) on Day 3. No fluid imbalance or cytochrome P 1A2 induction due to concomitant medications was identified during the treatment course to account for such increases in V and CL, respectively. Possible mechanisms underlying these changes are discussed. CONCLUSIONS This is the first report of clinical pharmacokinetics of riluzole in patients with SCI. The C(max) and AUC(0-12) achieved in SCI patients were lower than those in ALS patients on the same dose basis, due to a higher clearance and larger volume of distribution in SCI patients. The finding in SCI patients of an increase in the clearance and distribution of riluzole between the 3rd and 14th days after SCI, with a lower plasma concentration of riluzole on the 14th day, stresses the importance of monitoring changes in drug metabolism after SCI in interpreting the safety and efficacy of therapeutic drugs that are used in clinical trials in SCI. Clinical trial registration no.: NCT00876889.
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Affiliation(s)
- Diana S L Chow
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas 77030, USA.
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Contrasting effects of cord injury on intravenous and oral pharmacokinetics of diclofenac: a drug with intermediate hepatic extraction. Spinal Cord 2012; 50:632-5. [DOI: 10.1038/sc.2012.20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mestre H, Alkon T, Salazar S, Ibarra A. Spinal cord injury sequelae alter drug pharmacokinetics: an overview. Spinal Cord 2011; 49:955-60. [PMID: 21625241 DOI: 10.1038/sc.2011.58] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Literature review. OBJECTIVES Critical review of the literature published on the physiological alterations caused by spinal cord injury (SCI) and their effect on the pharmacokinetic parameters of commonly employed drugs. The review introduces the most recent treatment protocols of a variety of drugs, enabling the modern clinician to apply efficacious and cost-effective solutions to the pharmacological treatment of SCI patients. METHODS Studies published in international indexed journals up to January 2011 were selected from the PubMed database. RESULTS The review evaluated the sequelae of SCI and their effect on pharmacological processes. The results demonstrated that these alterations affected the pharmacokinetics of drugs commonly administered to SCI patients, such as antibiotics, muscle relaxants, immunosuppressants and analgesics. CONCLUSION There are multiple etiologies to SCI and patients present with varying degrees of impairment. Factors such as level of injury and completeness of the injury create a very heterogeneous population within the SCI community. The heterogeneity of this population creates a problem when trying to standardize pharmacokinetic (PK) parameters. It is because of this that specific physiological alterations must be linked to changes in PK and be identified within the clinical setting. This relationship between physiology and PK enables the clinician to be alert for possible pharmacological complications in individual patients based on their clinical manifestations. Future research should aim to develop rigorous therapeutic guidelines tailored to the diverse manifestations of SCI so as to provide effective, affordable and safe pharmacotherapy.
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Affiliation(s)
- H Mestre
- Facultad de Ciencias de la Salud, Universidad Anáhuac México Norte, Huixquilucan Edo. de México, México
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Rabchevsky AG, Patel SP, Springer JE. Pharmacological interventions for spinal cord injury: where do we stand? How might we step forward? Pharmacol Ther 2011; 132:15-29. [PMID: 21605594 DOI: 10.1016/j.pharmthera.2011.05.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 04/28/2011] [Indexed: 12/15/2022]
Abstract
Despite numerous studies reporting some measures of efficacy in the animal literature, there are currently no effective therapies for the treatment of traumatic spinal cord injuries (SCI) in humans. The purpose of this review is to delineate key pathophysiological processes that contribute to neurological deficits after SCI, as well as to describe examples of pharmacological approaches that are currently being tested in clinical trials, or nearing clinical translation, for the therapeutic management of SCI. In particular, we will describe the mechanistic rationale to promote neuroprotection and/or functional recovery based on theoretical, yet targeted pathological events. Finally, we will consider the clinical relevancy for emerging evidence that pharmacologically targeting mitochondrial dysfunction following injury may hold the greatest potential for increasing tissue sparing and, consequently, the extent of functional recovery following traumatic SCI.
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Affiliation(s)
- Alexander G Rabchevsky
- Spinal Cord & Brain injury Research Center, Lexington, University of Kentucky, KY 40536-0509, USA.
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McEwen ML, Sullivan PG, Rabchevsky AG, Springer JE. Targeting mitochondrial function for the treatment of acute spinal cord injury. Neurotherapeutics 2011; 8:168-79. [PMID: 21360236 PMCID: PMC3101832 DOI: 10.1007/s13311-011-0031-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Traumatic injury to the mammalian spinal cord is a highly dynamic process characterized by a complex pattern of pervasive and destructive biochemical and pathophysiological events that limit the potential for functional recovery. Currently, there are no effective therapies for the treatment of spinal cord injury (SCI) and this is due, in part, to the widespread impact of the secondary injury cascades, including edema, ischemia, excitotoxicity, inflammation, oxidative damage, and activation of necrotic and apoptotic cell death signaling events. In addition, many of the signaling pathways associated with these cascades intersect and initiate other secondary injury events. Therefore, it can be argued that therapeutic strategies targeting a specific biochemical cascade may not provide the best approach for promoting functional recovery. A "systems approach" at the subcellular level may provide a better strategy for promoting cell survival and function and, as a consequence, improve functional outcomes following SCI. One such approach is to study the impact of SCI on the biology and function of mitochondria, which serve a major role in cellular bioenergetics, function, and survival. In this review, we will briefly describe the importance and unique properties of mitochondria in the spinal cord, and what is known about the response of mitochondria to SCI. We will also discuss a number of strategies with the potential to promote mitochondrial function following SCI.
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Affiliation(s)
- Melanie L. McEwen
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536–0509 USA
- Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington, Kentucky 40536–0509 USA
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, Kentucky 40536–0509 USA
| | - Patrick G. Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536–0509 USA
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, Kentucky 40536–0509 USA
| | - Alexander G. Rabchevsky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536–0509 USA
- Department of Physiology, University of Kentucky, Lexington, Kentucky 40536–0509 USA
| | - Joe E. Springer
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536–0509 USA
- Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington, Kentucky 40536–0509 USA
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, Kentucky 40536–0509 USA
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Nout YS, Culp E, Schmidt MH, Tovar CA, Pröschel C, Mayer-Pröschel M, Noble MD, Beattie MS, Bresnahan JC. Glial restricted precursor cell transplant with cyclic adenosine monophosphate improved some autonomic functions but resulted in a reduced graft size after spinal cord contusion injury in rats. Exp Neurol 2010; 227:159-71. [PMID: 21040723 DOI: 10.1016/j.expneurol.2010.10.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/13/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
Abstract
Transplantation of glial restricted precursor (GRP) cells has been shown to reduce glial scarring after spinal cord injury (SCI) and, in combination with neuronal restricted precursor (NRP) cells or enhanced expression of neurotrophins, to improve recovery of function after SCI. We hypothesized that combining GRP transplants with rolipram and cAMP would improve functional recovery, similar to that seen after combining Schwann cell transplants with increasing cAMP. A short term study, (1) uninjured control, (2) SCI+vehicle, and (3) SCI+cAMP, showed that spinal cord [cAMP] was increased 14days after SCI. We used 51 male rats subjected to a thoracic SCI for a 12-week survival study: (1) SCI+vehicle, (2) SCI+GRP, (3) SCI+cAMP, (4) SCI+GRP+cAMP, and (5) uninjured endpoint age-matched control (AM). Rolipram was administered for 2weeks after SCI. At 9days after SCI, GRP transplantation and injection of dibutyryl-cAMP into the spinal cord were performed. GRP cells survived, differentiated, and formed extensive transplants that were well integrated with host tissue. Presence of GRP cells increased the amount of tissue in the lesion; however, cAMP reduced the graft size. White matter sparing at the lesion epicenter was not affected. Serotonergic input to the lumbosacral spinal cord was not affected by treatment, but the amount of serotonin immediately caudal to the lesion was reduced in the cAMP groups. Using telemetric monitoring of corpus spongiosum penis pressure we show that the cAMP groups regained the same number of micturitions per 24hours when compared to the AM group, however, the frequency of peak pressures was increased in these groups compared to the AM group. In contrast, the GRP groups had similar frequency of peak pressures compared to baseline and the AM group. Animals that received GRP cells regained the same number of erectile events per 24hours compared to baseline and the AM group. Since cAMP reduced the GRP transplant graft, and some modest positive effects were seen that could be attributable to both GRP or cAMP, future research is required to determine how cAMP affects survival, proliferation, and/or function of progenitor cells and how this is related to function. cAMP may not always be a desirable addition to a progenitor cell transplantation strategy after SCI.
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Affiliation(s)
- Yvette S Nout
- Brain and Spinal Injury Center, Department of Neurological Surgery, 1001 Potrero Ave. Bld 1 Rm 101, University of California, San Francisco, CA 94110, USA.
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Abstract
STUDY DESIGN Cell transplantation strategies are gaining increasing interest for spinal cord injury (SCI) with the objective of promoting spinal cord repair. To avoid allogenic graft rejection, an adequate immune suppression is required, and one of the most potent and commonly used immunosuppressives is cyclosporin A (CsA). In SCI, permanent sensory motor loss is combined with modifications of drug absorption, distribution and elimination. OBJECTIVES The objectives of this study were to thoroughly explore histological and functional outcomes of CsA treatment in a rat model of spinal cord compression. SETTING Experiments were carried out at the Institute for Neurosciences of Montpellier (France), the Integrative Biology of Neurodegeneration Laboratory (Spain) and in the Novartis Institutes for BioMedical Research (Switzerland) for CsA blood concentration determination. METHODS We first evaluated histological outcomes of CsA treatment on kidneys and spinal cord after SCI. We then investigated whether SCI modified CsA blood concentration. Finally, using behavioral analysis, we assessed the potential CsA impact on functional recovery. RESULTS When spinal-cord-injured rats were treated with a CsA dose of 10 mg kg(-1) per day, we observed deleterious effects on kidneys, associated with modifications of CsA blood concentration. Adding an antibiotic treatment reduced kidney alteration without modifying CsA blood concentration. Finally, we showed that CsA treatment per se modified neither functional recovery nor lesion extension. CONCLUSION This study pinpoints the absolute requirement of careful CsA monitoring in the clinical setting for patients with SCI to minimize potential unexpected effects and avoid therapeutic failure.
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Medeiros BA, dos Santos CL, Palheta RC, de Queiroz DAF, da Graça JRV, dos Santos AA, Rola FH, Lima AAM, Gondim FDAA. Spinal cord transection modifies ileal fluid and electrolyte transport in rats. Auton Neurosci 2008; 139:24-9. [PMID: 18230418 DOI: 10.1016/j.autneu.2007.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 12/15/2007] [Accepted: 12/17/2007] [Indexed: 10/22/2022]
Abstract
Spinal cord injury (SCI) is associated with severe autonomic changes, including inhibition of gastrointestinal (GI) motility. GI motility changes are known to affect electrolytes transport and these changes have not been adequately studied after SCI. We studied the ileal permeability to fluid and electrolytes in rats submitted to experimental spinal cord transection (SCT), between T4 and T5, throughout the first week after SCT. SCT increased ileal secretion of Na+ (P<0.05) and decreased the Cl(-) absorption during the first week post SCI (P<0.05). Water transport was also significantly altered, leading to increased water secretion following the Na+ gradient. Ileal secretion of K+ was significantly increased 1 and 7 days after spinal cord injury. To our knowledge, the present findings are the first direct evidence that SCT alters ileal electrolyte transport in rats. Further studies are necessary to evaluate the mechanisms involved in this phenomenon.
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Šedý J, Urdzíková L, Jendelová P, Syková E. Methods for behavioral testing of spinal cord injured rats. Neurosci Biobehav Rev 2008; 32:550-80. [DOI: 10.1016/j.neubiorev.2007.10.001] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 08/09/2007] [Accepted: 10/03/2007] [Indexed: 12/21/2022]
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Cui Q, Hodgetts SI, Hu Y, Luo JM, Harvey AR. Strain-specific differences in the effects of cyclosporin A and FK506 on the survival and regeneration of axotomized retinal ganglion cells in adult rats. Neuroscience 2007; 146:986-99. [PMID: 17408862 DOI: 10.1016/j.neuroscience.2007.02.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 01/14/2007] [Accepted: 02/14/2007] [Indexed: 02/07/2023]
Abstract
The immune response can influence neuronal viability and plasticity after injury, effects differing in strains of rats with different susceptibility to autoimmune disease. We assessed the effects of i.p. injections of cyclosporin A (CsA) or FK506 on adult retinal ganglion cell (RGC) survival and axonal regeneration into peripheral nerve (PN) autografted onto the cut optic nerve of rats resistant (Fischer F344) or vulnerable (Lewis) to autoimmune disease. Circulating and tissue CsA and FK506 levels were similar in both strains. Three weeks after autologous PN transplantation the number of viable beta-III tubulin-positive RGCs was significantly greater in CsA- and FK506-treated F344 rats compared with saline-injected controls. RGC survival in Lewis rats was not significantly altered. In F344 rats, retrograde labeling of RGCs revealed that CsA or FK506 treatment significantly increased the number of RGCs that regenerated an axon into a PN autograft; however these agents had no beneficial effect on axonal regeneration in Lewis rats. PN grafts in F344 rats also contained comparatively more pan-neurofilament immunoreactive axons. In both strains, 3 weeks after transplantation CsA or FK506 treatment resulted in increased retinal macrophage numbers, but only in F344 rats was this increase significant. At this time-point PN grafts in both strains contained many macrophages and some T cells. T cell numbers in Lewis rats were significantly greater than in F344 animals. The increased RGC axonal regeneration seen in CsA- or FK506-treated F344 but not Lewis rats shows that modulation of immune responses after neurotrauma has complex and not always predictable outcomes.
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Affiliation(s)
- Q Cui
- School of Anatomy and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, Western Australia 6009, Australia.
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García-López P, Martínez-Cruz A, Guízar-Sahagún G, Castañeda-Hernández G. Acute spinal cord injury changes the disposition of some, but not all drugs given intravenously. Spinal Cord 2006; 45:603-8. [PMID: 17179977 DOI: 10.1038/sj.sc.3102001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Experimental laboratory investigations in paraplegic rats. OBJECTIVE In order to understand why acute spinal cord injury (SCI) changes the disposition of some, but not all drugs given intravenously (i.v.), pharmacokinetic parameters of drugs with different pharmacological properties were evaluated to determine the influence of SCI on physiological processes such as distribution, metabolism and excretion. SETTING Mexico City, Mexico. METHODS Rats were subjected to severe SCI (contusion) at T-9 level; pharmacokinetic studies of phenacetin, naproxen or gentamicin were performed 24 h after. These drugs were not chosen as markers because of their therapeutic properties, but because of their pharmacokinetic characteristics. Additional studies including plasma proteins, liver and renal function tests, and micro-vascular hepatic blood flow, were also performed at the same time after injury. RESULTS Acute SCI significantly reduced distribution of drugs with intermediate and low binding to plasma proteins (phenacetin 30% and gentamicin 10%, respectively), but distribution did not change when naproxen - a drug highly bound to plasma proteins (99%) - was used, in absence of changes in plasma proteins. Metabolism was significantly altered only for a drug with liver blood flow - limited clearance (phenacetin) and not for a drug with liver capacity-limited clearance (naproxen). The liver function test did not change, whereas the hepatic micro-vascular blood flow significantly decreased after SCI. Renal excretion, evaluated by gentamicin clearance, was significantly reduced as a consequence of SCI, without significant changes in serum creatinine. CONCLUSIONS Changes in drug disposition associated to acute SCI are complex and generalization is not possible. They are highly dependent on each drug properties as well as on the altered physiological processes. Results motivate the quest for strategies to improve disposition of selective i.v. drugs during spinal shock, in an effort to avoid therapeutic failure.
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Affiliation(s)
- P García-López
- Laboratorio de Farmacología, Subdirección de Investigación Básica, Instituto Nacional de Cancerología, México, DF, México
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Abstract
The implantation of exogenous cells or tissues has been a popular and successful strategy to overcome physical discontinuity and support axon growth in experimental models of spinal cord injury (SCI). Cellular therapies exhibit a multifarious potential for SCI restoration, providing not only a supportive substrate upon which axons can traverse the injury site, but also reducing progressive tissue damage and scarring, facilitating remyelination repair, and acting as a source for replacing and re-establishing lost neural tissue and its circuitry. The past two decades of research into cell therapies for SCI repair have seen the progressive evolution from whole tissue strategies, such as peripheral nerve grafts, to the use of specific, purified cell types from a diverse range of sources and, recently, to the employment of stem or neural precursor cell populations that have the potential to form a full complement of neural cell types. Although the progression of cell therapies from laboratory to clinical implementation has been slow, human SCI safety and efficacy trials involving several cell types within the US appear to be close at hand.
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Affiliation(s)
- Damien D Pearse
- University of Miami Miller School of Medicine, The Miami Project to Cure Paralysis, Department of Neurological Surgery, Lois Pope Life Center, 1095 NW 14th Terrace (R-48), Miami, FL 33136, USA.
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17
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Austen SK, Fletcher LA, Fassett RG, Booth C, Coombes JS. Acute exposure to cyclosporine does not increase plasma homocysteine in rats. Transplant Proc 2006; 37:4543-6. [PMID: 16387165 DOI: 10.1016/j.transproceed.2005.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Indexed: 10/25/2022]
Abstract
There is interest in the postulate that cyclosporine a (CsA) contributes to the elevated homocysteine levels seen in organ transplant recipients, as hyperhomocysteinemia is now considered an independent risk factor for cardiovascular disease (CVD) and may partially explain the increased prevalence of CVD in this population. The main purpose of this investigation was to determine the effect of CsA administration on plasma homocysteine. Eighteen female Sprague Dawley rats (4 months old) were randomly assigned to either a treatment or a control group. For 18 days the treatment group received of CsA (25 mg/kg/d) while the control group received the same volume of the vehicle. Blood samples obtained following sacrifice to measure CsA, total homocysteine, and plasma creatinine. There were no significant differences in plasma homocysteine (mean values +/- SD: treatment = 4.79 +/- 0.63 micromol/L, control = 4.46 +/- 0.75 micromol/L; P = .37). Homocysteine was not significantly correlated with final CsA concentrations (r = .17; P = .69). There was a significant difference in plasma creatinine values between the two groups (treatment = 60.44 +/- 7.68 micromol/L, control = 46.33 +/- 1.66 micromol/L; P < .001). Furthermore, plasma homocysteine and creatinine were positively correlated with the treatment group (r = .73; P < .05) but not the controls (r = -.10; P = .81). In conclusion, CsA does not influence plasma homocysteine concentrations in rats.
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Affiliation(s)
- S K Austen
- School of Human Movement Studies, University of Queensland, St Luica, Australia
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18
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Cruz-Antonio L, Flores-Murrieta FJ, García-Löpez P, Guízar-Sahagún G, Castañeda-Hernández G. Understanding Drug Disposition Alterations Induced by Acute Spinal Cord Injury: Role of Injury Level and Route of Administration for Agents Submitted to Extensive Liver Metabolism. J Neurotrauma 2006; 23:75-85. [PMID: 16430374 DOI: 10.1089/neu.2006.23.75] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
It is known that acute spinal cord injury (SCI) produces hemodynamic alterations, including a reduction in liver blood flow that is more pronounced after high-thoracic than after low-thoracic injury. To determine if these changes have an impact in the pharmacokinetics of high extraction drugs (i.e., those drugs which clearance mainly depends on liver blood flow), we studied the pharmacokinetics of a model compound, phenacetin, and of its main metabolite, acetaminophen, in rats 24 h after a high (T1) or a low (T8) SCI, as well as in sham-lesioned controls. After intravenous administration to animals with SCI, reductions in drug clearance and distribution led to an increase in blood concentrations. These alterations were more pronounced after high than after low SCI, as expected from hemodynamic changes. After oral administration, phenacetin blood levels were similar in sham-lesioned and T1-injured animals, but decreased by injury at T8. This is likely due to a reduction in drug absorption which compensates the changes in distribution and elimination induced by injury at T1, whereas it prevails in T8-lesioned animals. Acetaminophen blood concentrations observed after intravenous or oral phenacetin, or after the oral administration of acetaminophen by itself, were increased or reduced, depending on the overall effect of the alterations on absorption, first pass metabolism, distribution and elimination induced by high and low SCI. Results demonstrate that acute SCI significantly alters the pharmacokinetics of high extraction drugs. The outcome of such alterations depends on the level of SCI and on the route of administration.
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19
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Lexis LA, Fassett RG, Coombes JS. alpha-Tocopherol and alpha-Lipoic Acid Enhance the Erythrocyte Antioxidant Defence in Cyclosporine A-Treated Rats. Basic Clin Pharmacol Toxicol 2006; 98:68-73. [PMID: 16433894 DOI: 10.1111/j.1742-7843.2006.pto_222.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of this study was to determine the effects of dietary antioxidant supplementation with alpha-tocopherol and alpha-lipoic acid on cyclosporine A (cyclosporine)-induced alterations to erythrocyte and plasma redox balance. Rats were randomly assigned to either control, antioxidant (alpha-tocopherol 1000 IU/kg diet and alpha-lipoic acid 1.6 g/kg diet), cyclosporine (25 mg/kg/day), or cyclosporine + antioxidant treatments. Cyclosporine was administered for 7 days after an 8 week feeding period. Plasma was analysed for alpha-tocopherol, total antioxidant capacity, malondialdehyde, and creatinine. Erythrocytes were analysed for glutathione, methaemoglobin, superoxide dismutase, catalase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, alpha-tocopherol and malondialdehye. Cyclosporine administration caused a significant decrease in superoxide dismutase activity (P<0.05 control versus cyclosporine) and this was improved by antioxidant supplementation (P<0.05 cyclosporine versus cyclosporine + antioxidant; P<0.05 control versus cyclosporine + antioxidant). Animals receiving cyclosporine and antioxidants showed significantly increased (P<0.05) catalase activity compared to both groups not receiving cyclosporine. Cyclosporine administration induced significant increases in plasma malondialdehyde and creatinine concentration (P<0.05 control versus cyclosporine). Antioxidant supplementation prevented the cyclosporine induced increase in plasma creatinine (P<0.05 cyclosporine versus cyclosporine + antioxidant; P>0.05 control versus cyclosporine + antioxidant), however, supplementation did not alter the cyclosporine induced increase in plasma malondialdehyde concentration (P>0.05 cyclosporine versus cyclosporine + antioxidant). Antioxidant supplementation resulted in significant increases (P<0.05) in plasma and erythrocyte alpha-tocopherol in both of the supplemented groups compared to non-supplemented groups. In conclusion, dietary supplementation with alpha-tocopherol and alpha-lipoic acid enhanced the erythrocyte antioxidant defence and reduced nephrotoxicity in cyclosporine treated animals.
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Affiliation(s)
- Louise A Lexis
- Physiology Laboratory, School of Community Health, Faculty of Health Studies, Charles Sturt University, Albury, 2640, Australia.
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20
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Lexis LA, Richards RS, Fassett RG, Coombes JS. Cyclosporine A-Induced Changes to Erythrocyte Redox Balance is Time Course-Dependent. Basic Clin Pharmacol Toxicol 2005; 97:135-40. [PMID: 16128906 DOI: 10.1111/j.1742-7843.2005.pto_973120.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclosporine A-treated transplant recipients develop pronounced cardiovascular disease and have increased oxidative stress and altered antioxidant capacity in erythrocytes and plasma. These experiments investigated the time-course of cyclosporine A-induced changes to redox balance in plasma and erythrocytes. Rats were randomly assigned to either a control or cyclosporine A-treated group. Treatment animals received 25 mg/kg of cyclosporine A via intraperitoneal injection for either 7 days or a single dose. Control rats were injected with the same volume of the vehicle. Three hours after the final injections, plasma was analysed for total antioxidant status, alpha-tocopherol, malondialdehyde, and creatinine. Erythrocytes were analysed for reduced glutathione (GSH), alpha-tocopherol, methaemoglobin, malondialdehyde, and the activities of superoxide dismutase, catalase, GSH peroxidase, and glucose-6-phosphate dehydrogenase (G6PD). Cyclosporine A administration for 7 days resulted in a significant increase (P<0.05) in plasma malondialdehyde, methaemoglobin, and superoxide dismutase and catalase activities. There was a significant decrease (P<0.05) in erythrocyte GSH concentration and G6PD activity in cyclosporine A animals. There were no significant differences (P>0.05) between groups following a single dose of cyclosporine A in any of the measures. In summary, cyclosporine A alters erythrocyte redox balance after 7 days administration, but not after a single dose.
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Affiliation(s)
- Louise A Lexis
- Physiology Laboratory, School of Community Health, Charles Sturt University, Albury, 2640, Australia.
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21
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Guízar-Sahagún G, Velasco-Hernández L, Martínez-Cruz A, Castañeda-Hernández G, Bravo G, Rojas G, Hong E. Systemic microcirculation after complete high and low thoracic spinal cord section in rats. J Neurotrauma 2005; 21:1614-23. [PMID: 15684653 DOI: 10.1089/neu.2004.21.1614] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Spinal cord injury (SCI) produces multiple systemic and metabolic alterations. Although some systemic alterations could be associated with ischemic organ damage, little is known about microvascular blood flow (MVBF) in organs other than the spinal cord after acute SCI. We used laser Doppler flowmetry in anesthetized rats to assess MVBF in several tissues before and after complete T-2 and T-9 SCI at 1 h and on days 1, 3, and 7 post-SCI. Mean arterial blood pressure (MAP), heart rate and hematologic variables also were recorded. MAP changes after T-2 injury were not significant, while MAP decreased significantly 1 h after T-9 injury. Statistically significant bradycardia occurred after T-2 injury at 7 days; statistically significant tachycardia occurred after T-9 injury at 1, 3, and 7 days. Hematocrit significantly increased at day 1 and decreased at days 3 and 7 after T-2 injury. SCI was associated with significant decreases in MVBF in liver, spleen, muscle and fore footpad skin. Changes in MVBF in hind footpad skin and kidney were not significant. Changes were more pronounced at 1 h and 1 day post-SCI. Significant differences between MVBF after T-2 and T-9 SCI occurred only in liver. MVBF significantly correlated with regional peripheral vascular resistances (assessed using the MAP/MVBF ratio), but not with MAP. In conclusion, organ-specific changes in systemic MVBF that are influenced by the level of SCI, could contribute to organ dysfunction.
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22
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Ibarra A, Correa D, Willms K, Merchant MT, Guizar-Sahagún G, Grijalva I, Madrazo I. Effects of cyclosporin-A on immune response, tissue protection and motor function of rats subjected to spinal cord injury. Brain Res 2003; 979:165-78. [PMID: 12850583 DOI: 10.1016/s0006-8993(03)02898-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of this work was to test the effect of cyclosporin-A (CsA) on some immunological, morphological and functional aspects developed after spinal cord injury. The specific cellular immune response against spinal cord constituents, the amount of spared tissue and myelination at the site of injury, and the motor function outcome were assessed in a first series of experiments. Rats were subjected to spinal cord compression and treated with cyclosporin-A before lesion and during the entire study. A specific lymphocyte response against spinal cord antigens was found in untreated spinal cord injured rats but not in cyclosporine-A treated injured rats. A significantly better myelination index was also found in injured cyclosporin-A-treated rats, as compared to untreated animals. The amount of spared spinal cord tissue at the epicenter was not significantly different comparing CsA-treated with vehicle-treated rats. Looking for a potential therapeutic use of CsA, in a second series of experiments, rats were subjected to spinal cord contusion and treated with cyclosporin-A from 1 to 72 h after lesion. Motor recovery and red nuclei neurons survival, were evaluated, and found to be significantly better in spinal cord injured rats treated with cyclosporin-A than in injured-untreated rats. This work confirms the existence of an autoimmune cellular reaction after injury that can be inhibited by cyclosporin-A treatment. Furthermore, cyclosporin-A promotes neuroprotection by diminishing both demyelination and neuronal cell death, resulting in a better motor outcome after spinal cord injury.
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Affiliation(s)
- Antonio Ibarra
- Unidad de Investigación Médica en Enfermedades Neurológicas, Centro Médico Nacional Siglo XXI, IMSS, DF, México, Mexico.
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23
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Dumont RJ, Verma S, Okonkwo DO, Hurlbert RJ, Boulos PT, Ellegala DB, Dumont AS. Acute spinal cord injury, part II: contemporary pharmacotherapy. Clin Neuropharmacol 2001; 24:265-79. [PMID: 11586111 DOI: 10.1097/00002826-200109000-00003] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Spinal cord injury (SCI) remains a common and devastating problem of modern society. Through an understanding of underlying pathophysiologic mechanisms involved in the evolution of SCI, treatments aimed at ameliorating neural damage may be developed. The possible pharmacologic treatments for acute spinal cord injury are herein reviewed. Myriad treatment modalities, including corticosteroids, 21-aminosteroids, opioid receptor antagonists, gangliosides, thyrotropin-releasing hormone (TRH) and TRH analogs, antioxidants and free radical scavengers, calcium channel blockers, magnesium replacement therapy, sodium channel blockers, N -methyl-D-aspartate receptor antagonists, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid-kainate receptor antagonists, modulators of arachadonic acid metabolism, neurotrophic growth factors, serotonin antagonists, antibodies against inhibitors of axonal regeneration, potassium channel blockers (4-aminopyridine), paclitaxel, clenbuterol, progesterone, gabexate mesylate, activated protein C, caspase inhibitors, tacrolimus, antibodies against adhesion molecules, and other immunomodulatory therapy have been studied to date. Although most of these agents have shown promise, only one agent, methylprednisolone, has been shown to provide benefit in large clinical trials. Given these data, many individuals consider methylprednisolone to be the standard of care for the treatment of acute SCI. However, this has not been established definitively, and questions pertaining to methodology have emerged regarding the National Acute Spinal Cord Injury Study trials that provided these conclusions. Additionally, the clinical significance (in contrast to statistical significance) of recovery after methylprednisolone treatment is unclear and must be considered in light of the potential adverse effects of such treatment. This first decade of the new millennium, now touted as the Decade of the Spine, will hopefully witness the emergence of universal and efficacious pharmacologic therapy and ultimately a cure for SCI.
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Affiliation(s)
- R J Dumont
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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24
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Chow SY, Moul J, Tobias CA, Himes BT, Liu Y, Obrocka M, Hodge L, Tessler A, Fischer I. Characterization and intraspinal grafting of EGF/bFGF-dependent neurospheres derived from embryonic rat spinal cord. Brain Res 2000; 874:87-106. [PMID: 10960593 DOI: 10.1016/s0006-8993(00)02443-4] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent advances in the isolation and characterization of neural precursor cells suggest that they have properties that would make them useful transplants for the treatment of central nervous system disorders. We demonstrate here that spinal cord cells isolated from embryonic day 14 Sprague-Dawley and Fischer 344 rats possess characteristics of precursor cells. They proliferate as undifferentiated neurospheres in the presence of EGF and bFGF and can be maintained in vitro or frozen, expanded and induced to differentiate into both neurons and glia. Exposure of these cells to serum in the absence of EGF and bFGF promotes differentiation into astrocytes; treatment with retinoic acid promotes differentiation into neurons. Spinal cord cells labeled with a nuclear dye or a recombinant adenovirus vector carrying the lacZ gene survive grafting into the injured spinal cord of immunosuppressed Sprague-Dawley rats and non-immunosuppressed Fischer 344 rats for up to 4 months following transplantation. In the presence of exogenously supplied BDNF, the grafted cells differentiate into both neurons and glia. These spinal cord cell grafts are permissive for growth by several populations of host axons, especially when combined with exogenous BDNF administration, as demonstrated by penetration into the graft of axons immunopositive for 5-HT and CGRP. Thus, precursor cells isolated from the embryonic spinal cord of rats, expanded in culture and genetically modified, are a promising type of transplant for repair of the injured spinal cord.
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Affiliation(s)
- S Y Chow
- Department of Neurobiology and Anatomy, MCP Hahnemann University, 3200 Henry Avenue, Philadelphia, PA 19129, USA.
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25
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García-López P, Salas R. Bioavailability of diclofenac after intramuscular administration to rats with experimental spinal cord injury. J Pharmacol Toxicol Methods 1999; 42:99-101. [PMID: 10924893 DOI: 10.1016/s1056-8719(00)00049-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Spinal cord injury (SCI) has been proposed to reduce drug bioavailability after intramuscular administration owing to an impairment in blood flow to paralyzed limbs. To test this hypothesis, we studied diclofenac bioavailability after intramuscular administration in rats with SCI. Female Sprague-Dawley rats were submitted to SCI at the T8 level by contusion and received a 10-mg/kg intramuscular diclofenac dose in the thigh of the right hind limb 24 h after injury. Blood samples were drawn, diclofenac concentration was determined by high-performance liquid chromatography, and whole-blood concentration against time curves were constructed. SCI did not result in a significant change in C(max) and T(max), compared with sham-lesioned controls, suggesting that the rate of drug absorption was not altered. Half-life was prolonged, and therefore area under the curve was greater in SCI than in sham-lesioned animals. Therefore, 24 h after SCI at the T8 level, intramuscular diclofenac bioavailability was not impaired but was actually enhanced. Results suggest that the rate of intramuscular diclofenac absorption is not significantly altered, although its elimination is impaired, during the acute phase of SCI. It then appears that SCI-induced pharmacokinetic alterations are complex, the global bioavailability depending on the sum of SCI effects on absorption, distribution, and elimination. Systematic studies on SCI-induced alterations are thus required to provide information leading to a rational dosing regimen design for SCI patients.
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Affiliation(s)
- P García-López
- División de Investigación Básica, Instituto Nacional de Cancerología, Mexico.
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26
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Liu Y, Himes BT, Solowska J, Moul J, Chow SY, Park KI, Tessler A, Murray M, Snyder EY, Fischer I. Intraspinal delivery of neurotrophin-3 using neural stem cells genetically modified by recombinant retrovirus. Exp Neurol 1999; 158:9-26. [PMID: 10448414 DOI: 10.1006/exnr.1999.7079] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neural stem cells have been shown to participate in the repair of experimental CNS disorders. To examine their potential in spinal cord repair, we used retroviral vectors to genetically modify a clone of neural stem cells, C17, to overproduce neurotrophin-3 (NT-3). The cells were infected with a retrovirus construct containing the NT-3.IRES.lacZ/neo sequence and cloned by limiting dilution and selection for lacZ expression. We studied the characteristics of the modified neural stem cells in vitro and after transplantation into the intact spinal cord of immunosuppressed adult rats. Our results show that: (i) most of the genetically modified cells express both NT-3 and lacZ genes with a high coexpression ratio in vitro and after transplantation; and (ii) large numbers of the xenografted cells survive in the spinal cord of adult rats for at least 2 months, differentiate into neuronal and glial phenotypes, and migrate for long distances. We conclude that genetically modified neural stem cells, acting as a source of neurotrophic factors, have the potential to participate in spinal cord repair.
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Affiliation(s)
- Y Liu
- Department of Neurobiology and Anatomy, Medical College of Pennsylvania Hahnemann University, Philadelphia 19129, USA
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27
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Ibarra A, Reyes J, Martínez S, Correa D, Guízar-Sahagún G, Grijalva I, Castañeda-Hernández G, Flores-Murrieta FJ, Franco-Bourland R, Madrazo I. Use of cyclosporin-A in experimental spinal cord injury: design of a dosing strategy to maintain therapeutic levels. J Neurotrauma 1996; 13:569-72. [PMID: 8915908 DOI: 10.1089/neu.1996.13.569] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cyclosporin-A (CsA) is frequently used as an immunosuppressive agent in experimental transplantations. CsA has been used in nervous tissue transplants in spinal cord injury (SCI). However, optimal results have not been obtained. This is likely due to the fact that SCI alters CsA pharmacokinetics and hence fixed dose regimens are not adequate. In this study, several CsA dosing regimens were evaluated in Long-Evans female rats subjected to a severe low thoracic (T8) SCI by the contusion method. Serum CsA concentrations were measured to determine which dosing regimen allowed CsA levels to be maintained within the therapeutic window. It was found that administration of 2.5 mg/kg/12 h intraperitoneally during the first 2 days after SCI (acute phase) followed by 5 mg/kg/12 h orally thereafter (subacute and chronic phases) yields CsA circulating levels within the therapeutic window, i.e., 0.120-0.275 microgram/mL. This dosing regimen represents a suitable alternative to fixed dosing to achieve an optimal CsA-induced immunosuppression in experimental models of SCI.
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Affiliation(s)
- A Ibarra
- Proyecto CAMINA, A.C., México, D.F
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28
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Guizar-Sahagun G, García-López P, Espitia AL, Méndez S, Castañeda-Hernández G, Madrazo I, Franco-Bourland RE. Histochemical evidence of the increased expression of nicotinamide adenine dinucleotide phosphate-dependent diaphorase in neurons of the myenteric plexus after acute spinal cord injury in adult rats. Neurosci Lett 1996; 206:185-8. [PMID: 8710182 DOI: 10.1016/s0304-3940(96)12469-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The expression of nitric oxide synthase in neurons of the gastrointestinal tract (GIT) after experimental spinal cord injury (SCI) was assessed in adult rats contused at T8. One day and 10 weeks after injury, specimens along the GIT were studied for NADPH-diaphorase histochemistry. A significant increase in the number of positive cell bodies and fibers in the myenteric plexus were observed 1 day after SCI, as compared to specimens from control and chronically injured rats, with the exception of the colon, which showed unchanged or decreased number of positive neurons in the acute and chronic stages, respectively. Positive neurons in the submucous plexus remained unchanged, excepting an increase in the colon after acute SCI, and a decrease in the duodenum in chronically injured rats. The altered nitric oxide neurotransmission in the GIT may be relevant to its reduced motility after SCI.
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