Immunoactivation and Altered Intercellular Communication Mediate the Pathophysiology of Spinal Cord Injury

Acute spinal cord injury: Pathophysiology and pharmacological intervention (Review)

Spinal cord injury (SCI) is one of the most debilitating of all the traumatic conditions that afflict individuals. For a number of years, extensive studies have been conducted to clarify the molecular mechanisms of SCI. Experimental and clinical studies have indicated that two phases, primary damage and secondary damage, are involved in SCI. The initial mechanical damage is caused by local impairment of the spinal cord. In addition, the fundamental mechanisms are associated with hyperflexion, hyperextension, axial loading and rotation. By contrast, secondary injury mechanisms are led by systemic and cellular factors, which may also be initiated by the primary injury. Although significant advances in supportive care have improved clinical outcomes in recent years, a number of studies continue to explore specific pharmacological therapies to minimize SCI. The present review summarized some important pathophysiologic mechanisms that are involved in SCI and focused on several pharmacological and non‑pharmacological therapies, which have either been previously investigated or have a potential in the management of this debilitating injury in the near future.

Treatment of acute transverse myelitis and its early complications

Acute transverse myelitis (ATM) has many potential etiologies, but a significant proportion of cases are categorized as idiopathic despite thorough evaluation. Clinical presentation of ATM typically includes some combination of motor weakness, sensory symptoms, and bowel and bladder dysfunction. Prompt recognition, even before a final etiologic diagnosis is reached, is critical to initiating early therapeutic intervention to reduce the harmful effects of inflammation. Acute therapeutic options for ATM include corticosteroids, plasma exchange, IV immunoglobulin, and chemotherapeutic agents such as cyclophosphamide. In some instances, combinations of these therapies are used. This article examines the therapeutic approach to ATM and its various acute clinical manifestations.

Single-dose gentamicin clearance is a predictor of creatinine clearance in spinal man

To identify a radionuclide-free, SCI (spinal cord injury) population-specific method for estimating renal function utilizing the total body clearance of gentamicin as a measure of creatinine clearance (CL(cr)) and glomerular filtration rate (GFR). To incorporate SCI population-specific patient variables into a predictive model for estimating CLcr and GFR. A retrolective study of gentamicin clearance as a measure of GFR in patients with SCI. Each patient had received a single, intravenous dose of gentamicin. Simultaneously, a 24-hour creatinine clearance (CL(cr-24)) was obtained. Experimentally measured total body clearance of a single intravenous administration of gentamicin (CL(gent-iv)) was estimated from PK analyses of gentamicin disposition in patients with SCI. Comparisons were made between CL(gent-iv) and predictors of GFR derived from a SCI population-specific nomogram (SCI-psn), the method of Cockcroft and Gault (C-G), CL(cr-24), and a multiplicative statistical model. A multiplicative model, calculated gentamicin clearance (CL(gent-calc)), that incorporates SCI population-specific characteristics to predict CL(cr-24) and GFR was derived from a multivariate nonlinear regression analysis, and the strengths of association between CL(gent-iv) and CL(gent-calc), and estimates of GFR derived from the method of C-G, SCI-psn, and CL(cr-24) were tested. The best predictive performance was demonstrated for CL(gent-iv) and the multiplicative model, CL(gent-calc), when tested against CL(cr-24) or the SCI-psn, supporting our premise that CL(gent-iv) can be used to estimate GFR in SCI. CL(gent-iv) and CL(gent-calc) outperformed CL(cr-24), the method of C-G, and the SCI-psn as predictors of GFR. The multiplicative model produced estimates of CL(gent-iv) which were more precise and less biased than CL(cr-24), the standard radiation-free predictor of GFR in patients with SCI, the SCI-psn, and the C-G equation. In this preliminary study, the clearance of gentamicin administered intravenously, CL(gent-iv), correlated highly with simultaneously measured CL(cr-24). CL(gent-iv) and our predictive model, CL(gent-calc), are more precise and less biased predictors of GFR in SCI than CL(cr-24). CL(gent-iv) and CL(gent-calc) seem to be clinically useful alternatives to CL(cr-24), the method of C-G, and the SCI-psn.

Magnetic resonance tracking of magnetically labeled autologous bone marrow CD34+ cells transplanted into the spinal cord via lumbar puncture technique in patients with chronic spinal cord injury: CD34+ cells' migration into the injured site

The purpose of this study was to demonstrate the possibility of delivering autologous bone marrow precursor cells into the spinal cord via lumbar puncture technique (LP) in patients with spinal cord injury (SCI). Magnetic resonance imaging provides a noninvasive method for studying the fate of transplanted cells in vivo. Considering these propositions, we studied magnetic resonance tracking of autologous bone marrow CD34(+) cells labeled with magnetic nanoparticles delivered into the spinal cord via LP in patients with SCI. Sixteen patients with chronic SCI were enrolled and divided into two groups; one group got their own labeled-CD34(+) cells injected into the spinal cord via LP (n = 10); the others received an injection, but it contained magnetic beads without stem cells (controls, n = 6). CD34(+) cells were magnetically labeled with magnetic beads coated with a monoclonal antibody specific for the CD34 cell membrane antigen. Magnetic resonance images were obtained by a standard turbospin echo-T2 weighted sequences before and 20 and 35 days after post-transplantation. The median number of CD34(+) cells injected via LP was 0.7 x 10(6) (range 0.45 to 1.22 x 10(6)). Magnetically labeled CD34(+) cells were visible at the lesion site as hypointense signals in five patients of the labeled-CD34(+) group 20 and 35 days after transplantation; these signals were not visible in any patient of the control group. We suggested for the first time that autologous bone marrow CD34(+) cells labeled with magnetic nanoparticles delivered into the spinal cord via LP technique migrated into the injured site in patients with chronic SCI.

Spinal cord injury--scientific challenges for the unknown future

The history of spinal cord injuries starts with the ancient Egyptian medical papyrus known as the Edwin Smith Surgical Papyrus. The papyrus written about 2500 B.C.by the physician and architect of the Sakkara pyramids Imhotep, describes "crushed vertebra in his neck" as well as symptoms of neurological deterioration. An ailment not to be treated was the massage to the patients at that time. This fatalistic attitude remained until the end of World War II when the first rehabilitation centre focused on the rehabilitation of spinal cord injured patients was opened. Our knowledge of the pathophysiological processes, both the primary as well as the secondary, has increased tremendously. However, all this knowledge has only led to improved medical care but not to any therapeutic method to restore, even partially, the neurological function. Neuroprotection is defined as measures to counteract secondary injury mechanisms and/or limit the extent of damage caused by self-destructive cellular and tissue processes. The co-existence of several distinctly different injury mechanisms after trauma has provided opportunities to explore a large number of potentially neuroprotective agents in animal experiments such as methylprednisolone sodium succinate. The results of this research have been very discouraging and pharmacological neuroprotection for patients with spinal cord injury has fallen short of the expectations created by the extensive research and promising observations in animal experiments. The focus of research has now, instead, been transformed to the field of neural regeneration. This field includes the discovery of regenerating obstacles in the nerve cell and/or environmental factors but also various regeneration strategies such as bridging the gap at the site of injury as well as transplantation of foetal tissue and stem cells. The purpose of this review is to highlight selected experimental and clinical studies that form the basis for undertaking future challenges in the research field of spinal cord injury. We will focus our discussion on methods either preventing the consequences of secondary injury in the acute period (neuroprotection) and/or various techniques of neural regeneration in the sub-acute and chronic phase and finally expose some thoughts about future avenues within this scientific field.