Effect of body mass index on survival after spinal cord injury

Introduction

Increased mortality after acute and chronic spinal cord injury (SCI) remains a challenge and mandates a better understanding of the factors contributing to survival in these patients. This study investigated whether body mass index (BMI) measured after acute traumatic SCI is associated with a change in mortality.

Methods

A prospective longitudinal cohort study was conducted with 742 patients who were admitted to the Acute Spine Unit of the Vancouver General Hospital between 2004 and 2016 with a traumatic SCI. An investigation of the association between BMI on admission and long-term mortality was conducted using classification and regression tree (CART) and generalized additive models (spline curves) from acute care up to 7.7 years after SCI (chronic phase). Multivariable models were adjusted for (i) demographic factors (e.g., age, sex, and Charlson Comorbidity Index) and (ii) injury characteristics (e.g., neurological level and severity and Injury Severity Score).

Results

After the exclusion of incomplete datasets (n = 602), 643 patients were analyzed, of whom 102 (18.5%) died during a period up to 7.7 years after SCI. CART identified three distinct mortality risk groups: (i) BMI: > 30.5 kg/m2, (ii) 17.5-30.5 kg/m2, and (iii) < 17.5 kg/m2. Mortality was lowest in the high BMI group (BMI > 30.5 kg/m2), followed by the middle-weight group (17.5-30.5 kg/m2), and was highest in the underweight group (BMI < 17.5 kg/m2). High BMI had a mild protective effect against mortality after SCI (hazard ratio 0.28, 95% CI: 0.09-0.88, p = 0.029), concordant with a modest "obesity paradox". Moreover, being underweight at admission was a significant risk factor for mortality up to 7.7 years after SCI (hazard ratio 5.5, 95% CI: 2.34-13.17, p < 0.001).

Discussion

Mortality risk (1 month to 7.7 years after SCI) was associated with differences in BMI at admission. Further research is needed to better understand the underlying mechanisms. Given an established association of BMI with metabolic determinants, these results may suggest unknown neuro-metabolic pathways that are crucial for patient survival.

Inhibition of the Nogo-pathway in experimental spinal cord injury: a meta-analysis of 76 experimental treatments

Recovery after spinal cord injury (SCI) may be propagated by plasticity-enhancing treatments. The myelin-associated nerve outgrowth inhibitor Nogo-A (Reticulon 4, RTN4) pathway has been shown to restrict neuroaxonal plasticity in experimental SCI models. Early randomized controlled trials are underway to investigate the effect of Nogo-A/Nogo-Receptor (NgR1) pathway blockers. This systematic review and meta-analysis of therapeutic approaches blocking the Nogo-A pathway interrogated the efficacy of functional locomotor recovery after experimental SCI according to a pre-registered study protocol. A total of 51 manuscripts reporting 76 experiments in 1572 animals were identified for meta-analysis. Overall, a neurobehavioral improvement by 18.9% (95% CI 14.5-23.2) was observed. Subgroup analysis (40 experiments, N = 890) revealed SCI-modelling factors associated with outcome variability. Lack of reported randomization and smaller group sizes were associated with larger effect sizes. Delayed treatment start was associated with lower effect sizes. Trim and Fill assessment as well as Egger regression suggested the presence of publication bias. Factoring in theoretically missing studies resulted in a reduced effect size [8.8% (95% CI 2.6-14.9)]. The available data indicates that inhibition of the Nogo-A/NgR1pathway alters functional recovery after SCI in animal studies although substantial differences appear for the applied injury mechanisms and other study details. Mirroring other SCI interventions assessed earlier we identify similar factors associated with outcome heterogeneity.

Adverse Effect of Neurogenic, Infective, and Inflammatory Fever on Acutely Injured Human Spinal Cord

This study aims to determine the effect of neurogenic, inflammatory, and infective fevers on acutely injured human spinal cord. In 86 patients with acute, severe traumatic spinal cord injuries (TSCIs; American Spinal Injury Association Impairment Scale (AIS), grades A-C) we monitored (starting within 72 h of injury, for up to 1 week) axillary temperature as well as injury site cord pressure, microdialysis (MD), and oxygen. High fever (temperature ≥38°C) was classified as neurogenic, infective, or inflammatory. The effect of these three fever types on injury-site physiology, metabolism, and inflammation was studied by analyzing 2864 h of intraspinal pressure (ISP), 1887 h of MD, and 840 h of tissue oxygen data. High fever occurred in 76.7% of the patients. The data show that temperature was higher in neurogenic than non-neurogenic fever. Neurogenic fever only occurred with injuries rostral to vertebral level T4. Compared with normothermia, fever was associated with reduced tissue glucose (all fevers), increased tissue lactate to pyruvate ratio (all fevers), reduced tissue oxygen (neurogenic + infective fevers), and elevated levels of pro-inflammatory cytokines/chemokines (infective fever). Spinal cord metabolic derangement preceded the onset of infective but not neurogenic or inflammatory fever. By considering five clinical characteristics (level of injury, axillary temperature, leukocyte count, C-reactive protein [CRP], and serum procalcitonin [PCT]), it was possible to confidently distinguish neurogenic from non-neurogenic high fever in 59.3% of cases. We conclude that neurogenic, infective, and inflammatory fevers occur commonly after acute, severe TSCI and are detrimental to the injured spinal cord with infective fever being the most injurious. Further studies are required to determine whether treating fever improves outcome. Accurately diagnosing neurogenic fever, as described, may reduce unnecessary septic screens and overuse of antibiotics in these patients.

The spinal cord injury-induced immune deficiency syndrome: results of the SCIentinel study

Infections are prevalent after spinal cord injury (SCI), constitute the main cause of death and are a rehabilitation confounder associated with impaired recovery. We hypothesize that SCI causes an acquired lesion-dependent (neurogenic) immune suppression as an underlying mechanism to facilitate infections. The international prospective multicentre cohort study (SCIentinel; protocol registration DRKS00000122; n = 111 patients) was designed to distinguish neurogenic from general trauma-related effects on the immune system. Therefore, SCI patient groups differing by neurological level, i.e. high SCI [thoracic (Th)4 or higher]; low SCI (Th5 or lower) and severity (complete SCI; incomplete SCI), were compared with a reference group of vertebral fracture (VF) patients without SCI. The primary outcome was quantitative monocytic Human Leukocyte Antigen-DR expression (mHLA-DR, synonym MHC II), a validated marker for immune suppression in critically ill patients associated with infection susceptibility. mHLA-DR was assessed from Day 1 to 10 weeks after injury by applying standardized flow cytometry procedures. Secondary outcomes were leucocyte subpopulation counts, serum immunoglobulin levels and clinically defined infections. Linear mixed models with multiple imputation were applied to evaluate group differences of logarithmic-transformed parameters. Mean quantitative mHLA-DR [ln (antibodies/cell)] levels at the primary end point 84 h after injury indicated an immune suppressive state below the normative values of 9.62 in all groups, which further differed in its dimension by neurological level: high SCI [8.95 (98.3% confidence interval, CI: 8.63; 9.26), n = 41], low SCI [9.05 (98.3% CI: 8.73; 9.36), n = 29], and VF without SCI [9.25 (98.3% CI: 8.97; 9.53), n = 41, P = 0.003]. Post hoc analysis accounting for SCI severity revealed the strongest mHLA-DR decrease [8.79 (95% CI: 8.50; 9.08)] in the complete, high SCI group, further demonstrating delayed mHLA-DR recovery [9.08 (95% CI: 8.82; 9.38)] and showing a difference from the VF controls of -0.43 (95% CI: -0.66; -0.20) at 14 days. Complete, high SCI patients also revealed constantly lower serum immunoglobulin G [-0.27 (95% CI: -0.45; -0.10)] and immunoglobulin A [-0.25 (95% CI: -0.49; -0.01)] levels [ln (g/l × 1000)] up to 10 weeks after injury. Low mHLA-DR levels in the range of borderline immunoparalysis (below 9.21) were positively associated with the occurrence and earlier onset of infections, which is consistent with results from studies on stroke or major surgery. Spinal cord injured patients can acquire a secondary, neurogenic immune deficiency syndrome characterized by reduced mHLA-DR expression and relative hypogammaglobulinaemia (combined cellular and humoral immune deficiency). mHLA-DR expression provides a basis to stratify infection-risk in patients with SCI.

Lesional Antibody Synthesis and Complement Deposition Associate With De Novo Antineuronal Antibody Synthesis After Spinal Cord Injury

BACKGROUND AND OBJECTIVES

Spinal cord injury (SCI) disrupts the fine-balanced interaction between the CNS and immune system and can cause maladaptive aberrant immune responses. The study examines emerging autoantibody synthesis after SCI with binding to conformational spinal cord epitopes and surface peptides located on the intact neuronal membrane.

METHODS

This is a prospective longitudinal cohort study conducted in acute care and inpatient rehabilitation centers in conjunction with a neuropathologic case-control study in archival tissue samples ranging from acute injury (baseline) to several months thereafter (follow-up). In the cohort study, serum autoantibody binding was examined in a blinded manner using tissue-based assays (TBAs) and dorsal root ganglia (DRG) neuronal cultures. Groups with traumatic motor complete SCI vs motor incomplete SCI vs isolated vertebral fracture without SCI (controls) were compared. In the neuropathologic study, B cell infiltration and antibody synthesis at the spinal lesion site were examined by comparing SCI with neuropathologically unaltered cord tissue. In addition, the CSF in an individual patient was explored.

RESULTS

Emerging autoantibody binding in both TBA and DRG assessments was restricted to an SCI patient subpopulation only (16%, 9/55 sera) while being absent in vertebral fracture controls (0%, 0/19 sera). Autoantibody binding to the spinal cord characteristically detected the substantia gelatinosa, a less-myelinated region of high synaptic density involved in sensory-motor integration and pain processing. Autoantibody binding was most frequent after motor complete SCI (grade American Spinal Injury Association impairment scale A/B, 22%, 8/37 sera) and was associated with neuropathic pain medication. In conjunction, the neuropathologic study demonstrated lesional spinal infiltration of B cells (CD20, CD79a) in 27% (6/22) of patients with SCI, the presence of plasma cells (CD138) in 9% (2/22). IgG and IgM antibody syntheses colocalized to areas of activated complement (C9neo) deposition. Longitudinal CSF analysis of an additional single patient demonstrated de novo (IgM) intrathecal antibody synthesis emerging with late reopening of the blood-spinal cord barrier.

DISCUSSION

This study provides immunologic, neurobiological, and neuropathologic proof-of-principle for an antibody-mediated autoimmunity response emerging approximately 3 weeks after SCI in a patient subpopulation with a high demand of neuropathic pain medication. Emerging autoimmunity directed against specific spinal cord and neuronal epitopes suggests the existence of paratraumatic CNS autoimmune syndromes.

Spinal infection with intraspinal abscess or empyema and acute myelopathy: comparative analysis of diagnostics, therapy, complications and outcome in primary care

INTRODUCTION

This study on pyogenic spinal infections with intraspinal epidural involvement (PSI +) compared the outcome of patients with spinal cord injury (SCI) to those without (noSCI) taking diagnostic algorithm, therapy, and complications into account.

METHODS

Patients were enrolled in an ambispective study (2012-2017). Diagnostic and therapeutic algorithms, complications, and neurological outcome were analyzed descriptively. Survival was analyzed applying Kaplan-Meier method and Cox regression.

RESULTS

In total, 134 patients with a median (IQR) age of 72 (61-79) years were analyzed. Baseline characteristics were similar between the SCI (n = 55) and noSCI (n = 79). A higher percentage of endocarditis (9% vs. 0%; p = 0.03) was detected in the noSCI group. The majority (81%) received combinatorial therapy including spinal surgery and antibiotic treatment. The surgery complication rate was 16%. At discharge, improvement in neurologic function was present in 27% of the SCI patients. Length of stay, duration of ventilation and the burden of disease-associated complications were significantly higher in the SCI group (e.g., urinary tract infection, pressure ulcers). Lethality risk factors were age (HR 1.09, 95% CI 1.02-1.16, p = 0.014), and empyema/abscess extension (≥ 3 infected spinal segments, HR 4.72, 95% CI 1.57-14.20, p = 0.006), dominating over additional effects of Charlson comorbidity index, SCI, and type of treatment. The overall lethality rate was 11%.

CONCLUSION

PSI + are associated with higher in-hospital mortality, particularly when multiple spinal segments are involved. However, survival is similar with (SCI) or without myelopathy (noSCI). If SCI develops, the rate of disease complications is higher and early specialized SCI care might be substantial to reduce complication rates.

Baseline predictors of in-hospital mortality after acute traumatic spinal cord injury: data from a level I trauma center

Comorbidity scores are important predictors of in-hospital mortality after traumatic spinal cord injury (tSCI), but the impact of specific pre-existing diseases is unknown. This retrospective cohort study aims at identifying relevant comorbidities and explores the influence of end-of-life decisions. In-hospital mortality of all patients admitted to the study center after acute tSCI from 2011 to 2017 was assessed. A conditional inference tree analysis including baseline data, injury characteristics, and Charlson Comorbidity Index items was used to identify crucial predictors. End-of-life decisions were recorded. Three-hundred-twenty-one patients were consecutively enrolled. The median length of stay was 95.7 days (IQR 56.8-156.0). During inpatient care, 20 patients (6.2%) died. These patients were older (median: 79.0 (IQR 74.7-83.2) vs. 55.5 (IQR 41.4-72.3) years) and had a higher Charlson Comorbidity Index score (median: 4.0 (IQR 1.75-5.50) vs. 0.0 (IQR 0.00-1.00)) compared to survivors. Pre-existing kidney or liver disease were identified as relevant predictors of in-hospital mortality. End-of-life decisions were observed in 14 (70.0%) cases. The identified impairment of kidney and liver, important for drug metabolism and elimination, points to the need of careful decisions on pharmaceutical treatment regimens after tSCI. Appropriate reporting of end-of-life decisions is required for upcoming studies.

Cervical Spine Injuries with Acute Traumatic Spinal Cord Injury: Spinal Surgery Adverse Events and Their Association with Neurological and Functional Outcome

STUDY DESIGN

Monocenter case-control study.

OBJECTIVE

Effects of spinal surgical adverse events (SSAE) on clinical and functional outcome, length of stay, and treatment costs after traumatic cervical spinal cord injury (SCI).

SUMMARY OF BACKGROUND DATA

Traumatic SCI is a challenge for primary care centers because of the emergency setting and complex injury patterns. SSAE rates of up to 15% are reported for spine fractures without SCI. Little is known about SSAE after traumatic SCI and their outcome relevance.

METHODS

Acute traumatic cervical SCI patients were enrolled from 2011 to 2017. Cases with and without SSAE were compared regarding neurological recovery, functional outcome, secondary complications, mortality, length of stay, and treatment costs. Adjusted logistic regression and generalized estimating equation models were calculated for the endpoints ASIA impairment scale (AIS)-conversion and dysphagia. All analyses were run in the total and in a propensity score matched sample.

RESULTS

At least one SSAE occurred in 37 of 165 patients (22.4%). Mechanical instability and insufficient spinal decompression were the most frequent SSAE with 13 (7.9%) or 11 (6.7%) cases, respectively. The regression models adjusted for demographic, injury, and surgery characteristics demonstrated a reduced probability for AIS-conversion related to SSAE (OR [95% CI] 0.14 [0.03-0.74]) and additionally to single-sided ventral or dorsal surgical approach (0.12 [0.02-0.69]) in the matched sample. Furthermore, SSAE were associated with higher risk for dysphagia in the matched (4.77 [1.31-17.38]) and the total sample (5.96 [2.07-17.18]). Primary care costs were higher in cases with SSAE (median (interquartile range) 97,300 [78,200-112,300]) EUR compared with cases without SSAE (52,300 [26,700-91,200]) EUR.

CONCLUSION

SSAE are an important risk factor after acute traumatic cervical SCI with impact on neurological recovery, functional outcome, and healthcare costs. Reducing SSAE is a viable means to protect the limited intrinsic capacity for recovery from SCI.Level of Evidence: 4.

The Effect of Early Infection on the Rate of Volitional Voiding after Spinal Cord Injury: A Potential Modifiable Risk Factor for Bladder Outcomes

PURPOSE

Recently, it has been observed that early infections after spinal cord injury (SCI) are associated with decreased long-term motor and sensory recovery. We investigate the effects of early infection after SCI on long-term bladder function.

MATERIALS AND METHODS

We assessed data for the years 1995 to 2006 using the National Spinal Cord Injury Database. Postoperative wound infections and pneumonia were used to classify infections during the acute inpatient and rehabilitation periods. The effect of early infections on volitional voiding status at 1-year followup was assessed. Age, gender and neurological status at rehabilitation discharge (level of injury, American Spinal Injury Association Impairment Scale [AIS] and bilateral lower extremity motor scores) were included in multivariate logistic regression modeling to control for confounding.

RESULTS

Of the 3,561 persons studied, 1,233 (34.6%) had an early infection. Those with an infection during early recovery were less likely to void than their noninfected counterparts if in the AIS A (0.3% vs 1.9%, p=0.010), AIS B (3.8% vs 10.5%, p=0.018) and AIS C (29.1% vs 37.3%, p=0.071) classification, while those with less complete injuries (AIS D) did not appear to be affected (62.6% vs 65.4%, p=0.456). Similar findings were found when stratifying by lower extremity motor scores and persisted on multivariate analysis, where early infection decreased the odds of volitional voiding at 1-year followup (OR=0.79, p=0.042).

CONCLUSIONS

Infections during the early recovery period may modify volitional voiding at 1-year followup by 20% or more. Future investigations to confirm our findings and potentially evaluate mitigation strategies are warranted.

Association of age with the timing of acute spine surgery-effects on neurological outcome after traumatic spinal cord injury

PURPOSE

To investigate the association of age with delay in spine surgery and the effects on neurological outcome after traumatic spinal cord injury (SCI).

METHODS

Ambispective cohort study (2011-2017) in n = 213 patients consecutively enrolled in a Level I trauma center with SCI care in a metropolitan region in Germany. Age-related differences in the injury to surgery interval and conditions associated with its delay (> 12 h after SCI) were explored using age categories or continuous variables and natural cubic splines. Effects of delayed surgery or age with outcome were analyzed using multiple logistic regression.

RESULTS

The median age of the study population was 58.8 years (42.0-74.6 IQR). Older age (≥ 75y) was associated with a prolonged injury to surgery interval of 22.8 h (7.2-121.3) compared to 6.6 h (4.4-47.9) in younger patients (≤ 44y). Main reasons for delayed surgery in older individuals were secondary referrals and multimorbidity. Shorter time span to surgery (≤ 12 h) was associated with higher rates of ASIA impairment scale (AIS) conversion (OR 4.22, 95%CI 1.85-9.65), as mirrored by adjusted spline curves (< 20 h 20-25%, 20-60 h 10-20%, > 60 h < 10% probability of AIS conversion). In incomplete SCI, the probability of AIS conversion was lower in older patients [e.g., OR 0.09 (0.02-0.44) for'45-59y' vs.' ≤ 44y'], as confirmed by spline curves (< 40y 20-80%, ≥ 40y 5-20% probability).

CONCLUSION

Older patient age complexifies surgical SCI care and research. Tackling secondary referral to Level I trauma centers and delayed spine surgery imposes as tangible opportunity to improve the outcome of older SCI patients.

Peripheral white blood cell responses as emerging biomarkers for patient stratification and prognosis in acute spinal cord injury

PURPOSE OF REVIEW

To date, prognostication of patients after acute traumatic spinal cord injury (SCI) mostly relies on the neurological assessment of residual function attributed to lesion characteristics. With emerging treatment candidates awaiting to be tested in early clinical trials, there is a need for wholistic high-yield prognostic biomarkers that integrate both neurogenic and nonneurogenic SCI pathophysiology as well as premorbid patient characteristics.

RECENT FINDINGS

It is becoming clearer that effective prognostication after acute SCI would benefit from integrating an assessment of pathophysiological changes on a systemic level, and with that, extend from a lesion-centric approach. Immunological markers mirror tissue injury as well as host immune function and are easily accessible through routine blood sampling. New studies have highlighted the value of circulating white blood cells, neutrophils and lymphocytes in particular, as prognostic systemic indicators of SCI severity and outcomes.

SUMMARY

We survey recent advances in methods and approaches that may allow for a more refined diagnosis and better prognostication after acute SCI, discuss how these may help deepen our understanding of SCI pathophysiology, and be of use in clinical trials.

The neuroanatomical-functional paradox in spinal cord injury

Although lesion size is widely considered to be the most reliable predictor of outcome after CNS injury, lesions of comparable size can produce vastly different magnitudes of functional impairment and subsequent recovery. This neuroanatomical-functional paradox is likely to contribute to the many failed attempts to independently replicate findings from animal models of neurotrauma. In humans, the analogous clinical-radiological paradox could explain why individuals with similar injuries can respond differently to rehabilitation. We describe the neuroanatomical-functional paradox in the context of traumatic spinal cord injury (SCI) and discuss the underlying mechanisms of the paradox, including the concepts of lesion-affected and recovery-related networks. We also consider the various secondary complications that further limit the accuracy of outcome prediction in SCI and provide suggestions for how to increase the predictive, translational value of preclinical SCI models.

Prognostic value of early leukocyte fluctuations for recovery from traumatic spinal cord injury

BACKGROUND

Acute traumatic spinal cord injury (SCI) induces a systemic immune response involving circulating white blood cells (WBCs). How this response is influenced by overall trauma severity, the neurological level of injury and/or correlates with patient outcomes is poorly understood. The objective of this study was to identify relationships between early changes in circulating WBCs, injury characteristics and long-term patient outcomes in individuals with traumatic SCI.

METHODS

We retrospectively analysed data from 161 SCI patients admitted to Brisbane's Princess Alexandra Hospital (exploration cohort). Logistic regression models in conjunction with receiver operating characteristic (ROC) analyses were used to assess the strength of specific links between the WBC response, respiratory infection incidence and neurological outcomes (American Spinal Injury Association Impairment Scale (AIS) grade conversion). An independent validation cohort from the Trauma Hospital Berlin, Germany (n = 49) was then probed to assess the robustness of effects and disentangle centre effects.

RESULTS

We find that the extent of acute neutrophilia in human SCI patients is positively correlated with New Injury Severity Scores but inversely with the neurological outcome (AIS grade). Multivariate analysis demonstrated that acute SCI-induced neutrophilia is an independent predictor of AIS grade conversion failure, with an odds ratio (OR) of 4.16 and ROC area under curve (AUC) of 0.82 (P < 0.0001). SCI-induced lymphopenia was separately identified as an independent predictor of better recovery (OR = 24.15; ROC AUC = 0.85, P < 0.0001). Acute neutrophilia and increased neutrophil-lymphocyte ratios were otherwise significantly associated with respiratory infection presentation in both patient cohorts.

CONCLUSIONS

Our findings demonstrate the prognostic value of modelling early circulating neutrophil and lymphocyte counts with patient characteristics for predicting the longer term recovery after SCI.

Association of timing of gabapentinoid use with motor recovery after spinal cord injury

OBJECTIVE

To explore the hypothesis that earlier administration of acute gabapentinoids is beneficial to motor recovery after spinal cord injury in humans.

METHODS

This is an observational study using a cohort from the European Multi-Centre Study about Spinal Cord Injury. Patient charts were reviewed to extract information regarding the administration and timing of gabapentinoid anticonvulsants. The primary outcome measure was motor scores, as measured by the International Standards for Neurological Classification of Spinal Cord Injury, collected longitudinally in the first year after injury. Sensory scores (light touch and pinprick) and functional measures (Spinal Cord Independence Measure) were secondary outcomes. Linear mixed effects regression models included a drug-by-time interaction to determine whether exposure to gabapentinoids altered recovery of muscle strength in the first year after injury.

RESULTS

A total of 201 participants were included in the study and had a median age of 46 and baseline motor score of 50. Participants were mostly men (85%) with sensory and motor complete injuries (50%). Seventy individuals (35%) were administered gabapentinoids within the first 30 days after injury, and presented with similar demographics. In the longitudinal model, the administration of gabapentinoids within 30 days after injury was associated with improved motor recovery when compared to those who did not receive gabapentinoids during this time (3.69 additional motor points from 4 to 48 weeks after injury; p = 0.03). This effect size increased as administration occurred earlier after injury (i.e., a benefit of 4.68 points when administered within 5 days).

CONCLUSIONS

This retrospective, observational study provided evidence of the beneficial effect of gabapentinoid anticonvulsants on motor recovery after spinal cord injury. More critically, it highlighted a potential time dependence, suggesting that earlier intervention is associated with better outcomes.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that gabapentinoids improve motor recovery for individuals with acute spinal cord injury.

Clinical decision-making on spinal cord injury-associated pneumonia: a nationwide survey in Germany

STUDY DESIGN

Survey study.

OBJECTIVES

Spinal cord injury (SCI)-associated pneumonia (SCI-AP) is associated with poor functional recovery and a major cause of death after SCI. Better tackling SCI-AP requires a common understanding on how SCI-AP is defined. This survey examines clinical algorithms relevant for diagnosis and treatment of SCI-AP.

SETTING

All departments for SCI-care in Germany.

METHODS

The clinical decision-making on SCI-AP and the utility of the Centers for Disease Control and Prevention (CDC) criteria for diagnosis of 'clinically defined pneumonia' were assessed by means of a standardized questionnaire including eight case vignettes of suspected SCI-AP. The diagnostic decisions based on the case information were analysed using classification and regression trees (CART).

RESULTS

The majority of responding departments were aware of the CDC-criteria (88%). In the clinical vignettes, 38-81% of the departments diagnosed SCI-AP in accordance with the CDC-criteria and 7-41% diagnosed SCI-AP in deviation from the CDC-criteria. The diagnostic agreement was not associated with the availability of standard operating procedures for SCI-AP management in the departments. CART analysis identified radiological findings, fever, and worsened gas exchange as most important for the decision on SCI-AP. Frequently requested supplementary diagnostics were microbiological analyses, C-reactive protein, and procalcitonin. For empirical antibiotic therapy, the departments used (acyl-)aminopenicillins/β-lactamase inhibitors, cephalosporins, or combinations of (acyl-)aminopenicillins/β-lactamase inhibitors with fluoroquinolones or carbapenems.

CONCLUSIONS

This survey reveals a diagnostic ambiguity regarding SCI-AP despite the awareness of CDC-criteria and established SOPs. Heterogeneous clinical practice is encouraging the development of disease-specific guidelines for diagnosis and management of SCI-AP.

Effects of local hypothermia-rewarming on physiology, metabolism and inflammation of acutely injured human spinal cord

In five patients with acute, severe thoracic traumatic spinal cord injuries (TSCIs), American spinal injuries association Impairment Scale (AIS) grades A-C, we induced cord hypothermia (33 °C) then rewarming (37 °C). A pressure probe and a microdialysis catheter were placed intradurally at the injury site to monitor intraspinal pressure (ISP), spinal cord perfusion pressure (SCPP), tissue metabolism and inflammation. Cord hypothermia-rewarming, applied to awake patients, did not cause discomfort or neurological deterioration. Cooling did not affect cord physiology (ISP, SCPP), but markedly altered cord metabolism (increased glucose, lactate, lactate/pyruvate ratio (LPR), glutamate; decreased glycerol) and markedly reduced cord inflammation (reduced IL1β, IL8, MCP, MIP1α, MIP1β). Compared with pre-cooling baseline, rewarming was associated with significantly worse cord physiology (increased ICP, decreased SCPP), cord metabolism (increased lactate, LPR; decreased glucose, glycerol) and cord inflammation (increased IL1β, IL8, IL4, IL10, MCP, MIP1α). The study was terminated because three patients developed delayed wound infections. At 18-months, two patients improved and three stayed the same. We conclude that, after TSCI, hypothermia is potentially beneficial by reducing cord inflammation, though after rewarming these benefits are lost due to increases in cord swelling, ischemia and inflammation. We thus urge caution when using hypothermia-rewarming therapeutically in TSCI.

The Incidence and Management of Moderate to Severe Head Injury

BACKGROUND

The comprehensive expansion of the Trauma Register of the German Trauma Society (Deutsche Gesellschaft für Unfallchirurgie; TR-DGU) now enables, for the first time, studies on traumatic brain injury (TBI) with special attention to care processes, clinical course, and outcomes of treatment on discharge or transfer from the acute-care hospital.

METHODS

Retrospective analysis of patients documented in the TR-DGU in the period 2013-2017 who had moderate to severe head injury as defined by the Abbreviated Injury Scale (AIS).

RESULTS

In the period 2013-2017, 41 101 patients with moderate to severe TBI were treated in TR-DGU-associated hospitals in Germany (n = 605 hospitals), corresponding to 8220 cases per year and thus to a population-wide incidence of 10.1 cases per 100 000 persons per year. TBI was present as an isolated injury in 39.1% of cases. The mean age of the patients was 60 years (median; range 0-104 years), and the male-to-female ratio was 2:1. 97.5% of the patients had blunt trauma. Falls from a low height were the most common cause of TBI (38.7%). 43.6% of the patients were intubated before arriving at the hospital, and more than 95% underwent cranial tomographic imaging within 22 minutes of arrival (standard deviation [SD] = 17 minutes). 18.4% underwent an emergency neurosurgical procedure. The in-hospital mortality was 23.5%, corresponding to a population-wide mortality from TBI of 2.4 per 100 000 persons per year. More than half of the patients recovered well or with only mild disability; 14.9% had persistent severe disability or remained in a vegetative state.

CONCLUSION

Putting these figures in the appropriate international context requires the acquisition of comparable data in multiple countries and is the main task of international TBI consortia.

Outcome heterogeneity and bias in acute experimental spinal cord injury: A meta-analysis

OBJECTIVE

To determine whether and to what degree bias and underestimated variability undermine the predictive value of preclinical research for clinical translation.

METHODS

We investigated experimental spinal cord injury (SCI) studies for outcome heterogeneity and the impact of bias. Data from 549 preclinical SCI studies including 9,535 animals were analyzed with meta-regression to assess the effect of various study characteristics and the quality of neurologic recovery.

RESULTS

Overall, the included interventions reported a neurobehavioral outcome improvement of 26.3% (95% confidence interval 24.3-28.4). Response to treatment was dependent on experimental modeling paradigms (neurobehavioral score, site of injury, and animal species). Applying multiple outcome measures was consistently associated with smaller effect sizes compared with studies applying only 1 outcome measure. More than half of the studies (51.2%) did not report blinded assessment, constituting a likely source of evaluation bias, with an overstated effect size of 7.2%. Assessment of publication bias, which extrapolates to identify likely missing data, suggested that between 2% and 41% of experiments remain unpublished. Inclusion of these theoretical missing studies suggested an overestimation of efficacy, reducing the effect sizes by between 0.9% and 14.3%.

CONCLUSIONS

We provide empirical evidence of prevalent bias in the design and reporting of experimental SCI studies, resulting in overestimation of the effectiveness. Bias compromises the internal validity and jeopardizes the successful translation of SCI therapies from the bench to bedside.

Acute transient spinal paralysis and cardiac symptoms following an accidental epidural potassium infusion - a case report

BACKGROUND

To describe a case of an accidental epidural potassium infusion leading to an acute transient spinal paralysis and cardiac symptoms and review the literature on that topic.

CASE PRESENTATION

We report the case of an accidental infusion of 900 mg potassium chloride 7.45% (KCl) into the epidural space, which occurred during epidural analgesia in a 74-year-old patient suffering from immobilization due to lumbar back pain as well as from a paralytic Ileus. The event was resulting in vegetative symptoms, such as tachycardia and hypertension accompanied by a motor complete tetraplegia (AIS B) sub C2 with respiratory depression. The endotracheal intubation was necessary. The patient was treated with 40 mg dexamethasone intravenously, as well an epidural lavage with sodium chloride solution 0.9% (NaCl) through the epidural catheter. The neurologic symptoms completely resolved within five days. An elevation of troponin-T values and a reduced left ventricular ejection fraction (LVEF) of 40% accompanied by transient pectanginous pain were documented. An exertional dyspnea remained.

CONCLUSIONS

A symptom complex with elevated sympathetic nervous system activity up to a stress cardiomyopathy is possible following epidural potassium infusion. Additionally, generalized pain and muscle spasticity evolve and a progressive acute spinal cord injury syndrome can occur within minutes, accompanied by respiratory depression. Treatment consists of early intensive care and the symptomatic therapy of the associated symptoms, leading in most of the reported cases to a good clinical outcome.

Spinal cord injury-induced immunodeficiency is mediated by a sympathetic-neuroendocrine adrenal reflex

Acute spinal cord injury (SCI) causes systemic immunosuppression and life-threatening infections, thought to result from noradrenergic overactivation and excess glucocorticoid release via hypothalamus-pituitary-adrenal axis stimulation. Instead of consecutive hypothalamus-pituitary-adrenal axis activation, we report that acute SCI in mice induced suppression of serum norepinephrine and concomitant increase in cortisol, despite suppressed adrenocorticotropic hormone, indicating primary (adrenal) hypercortisolism. This neurogenic effect was more pronounced after high-thoracic level (Th1) SCI disconnecting adrenal gland innervation, compared with low-thoracic level (Th9) SCI. Prophylactic adrenalectomy completely prevented SCI-induced glucocorticoid excess and lymphocyte depletion but did not prevent pneumonia. When adrenalectomized mice were transplanted with denervated adrenal glands to restore physiologic glucocorticoid levels, the animals were completely protected from pneumonia. These findings identify a maladaptive sympathetic-neuroendocrine adrenal reflex mediating immunosuppression after SCI, implying that therapeutic normalization of the glucocorticoid and catecholamine imbalance in SCI patients could be a strategy to prevent detrimental infections.

Long-term functional outcome in patients with acquired infections after acute spinal cord injury

OBJECTIVE

To investigate whether prevalent hospital-acquired pneumonia and wound infection affect the clinical long-term outcome after acute traumatic spinal cord injury (SCI).

METHODS

This was a longitudinal cohort study within the prospective multicenter National Spinal Cord Injury Database (Birmingham, Alabama). We screened datasets of 3,834 patients enrolled in 20 trial centers from 1995 to 2005 followed up until 2016. Eligibility criteria were cervical SCI and American Spinal Cord Injury Association impairment scale A, B, and C. Pneumonia or postoperative wound infections (Pn/Wi) acquired during acute medical care/inpatient rehabilitation were analyzed for their association with changes in the motor items of the Functional Independence Measure (FIM_motor) using regression models (primary endpoint 5-year follow-up). Pn/Wi-related mortality was assessed as a secondary endpoint (10-year follow-up).

RESULTS

A total of 1,203 patients met the eligibility criteria. During hospitalization, 564 patients (47%) developed Pn/Wi (pneumonia n = 540; postoperative wound infection n = 11; pneumonia and postoperative wound infection n = 13). Adjusted linear mixed models after multiple imputation revealed that Pn/Wi are significantly associated with lower gain in FIM_motor up to 5 years after SCI (-7.4 points, 95% confidence interval [CI] -11.5 to -3.3). Adjusted Cox regression identified Pn/Wi as a highly significant risk factor for death up to 10 years after SCI (hazard ratio 1.65, 95% CI 1.26 to 2.16).

CONCLUSION

Hospital-acquired Pn/Wi are predictive of propagated disability and mortality after SCI. Pn/Wi qualify as a potent and targetable outcome-modifying factor. Pn/Wi prevention constitutes a viable strategy to protect functional recovery and reduce mortality. Pn/Wi can be considered as rehabilitation confounders in clinical trials.

Natural Killer (NK) Cell Functionality after human Spinal Cord Injury (SCI): protocol of a prospective, longitudinal study

Background

Natural killer (NK) cells comprise the main components of lymphocyte-mediated nonspecific immunity. Through their effector function they play a crucial role combating bacterial and viral challenges. They are also thought to be key contributors to the systemic spinal cord injury-induced immune-deficiency syndrome (SCI-IDS). SCI-IDS increases susceptibility to infection and extends to the post-acute and chronic phases after SCI.

Methods and design

The prospective study of NK cell function after traumatic SCI was carried out in two centers in Berlin, Germany. SCI patients and control patients with neurologically silent vertebral fracture also undergoing surgical stabilization were enrolled. Furthermore healthy controls were included to provide reference data. The NK cell function was assessed at 7 (5–9) days, 14 days (11–28) days, and 10 (8–12) weeks post-trauma. Clinical documentation included the American Spinal Injury Association (ASIA) impairment scale (AIS), neurological level of injury, infection status, concomitant injury, and medications. The primary endpoint of the study is CD107a expression by NK cells (cytotoxicity marker) 8–12 weeks following SCI. Secondary endpoints are the NK cell’s TNF-α and IFN-γ production by the NK cells 8–12 weeks following SCI.

Discussion

The protocol of this study was developed to investigate the hypotheses whether i) SCI impairs NK cell function throughout the post-acute and sub-acute phases after SCI and ii) the degree of impairment relates to lesion height and severity. A deeper understanding of the SCI-IDS is crucial to enable strategies for prevention of infections, which are associated with poor neurological outcome and elevated mortality.

Trial registration

DRKS00009855.

SCISSOR-Spinal Cord Injury Study on Small molecule-derived Rho inhibition: a clinical study protocol

INTRODUCTION

The approved analgesic and anti-inflammatory drugs ibuprofen and indometacin block the small GTPase RhoA, a key enzyme that impedes axonal sprouting after axonal damage. Inhibition of the Rho pathway in a central nervous system-effective manner requires higher dosages compared with orthodox cyclooxygenase-blocking effects. Preclinical studies on spinal cord injury (SCI) imply improved motor recovery after ibuprofen/indometacin-mediated Rho inhibition. This has been reassessed by a meta-analysis of the underlying experimental evidence, which indicates an overall effect size of 20.2% regarding motor outcome achieved after ibuprofen/indometacin treatment compared with vehicle controls. In addition, ibuprofen/indometacin may also limit sickness behaviour, non-neurogenic systemic inflammatory response syndrome (SIRS), neuropathic pain and heterotopic ossifications after SCI. Consequently, 'small molecule'-mediated Rho inhibition after acute SCI warrants clinical investigation.

METHODS AND ANALYSIS

Protocol of an investigator-initiated clinical open-label pilot trial on high-dose ibuprofen treatment after acute traumatic, motor-complete SCI. A sample of n=12 patients will be enrolled in two cohorts treated with 2400 mg/day ibuprofen for 4 or 12 weeks, respectively. The primary safety end point is an occurrence of serious adverse events, primarily gastroduodenal bleedings. Secondary end points are pharmacokinetics, feasibility and preliminary effects on neurological recovery, neuropathic pain and heterotopic ossifications. The primary safety analysis is based on the incidence of severe gastrointestinal bleedings. Additional analyses will be mainly descriptive and casuistic.

ETHICS AND DISSEMINATION

The clinical trial protocol was approved by the responsible German state Ethics Board, and the Federal Institute for Drugs and Medical Devices. The study complies with the Declaration of Helsinki, the principles of Good Clinical Practice and all further applicable regulations. This safety and pharmacokinetics trial informs the planning of a subsequent randomised controlled trial. Regardless of the result of the primary and secondary outcome assessments, the clinical trial will be reported as a publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT02096913; Pre-results.

Olfactory Ensheathing Cell Transplantation in Experimental Spinal Cord Injury: Effect size and Reporting Bias of 62 Experimental Treatments: A Systematic Review and Meta-Analysis

Olfactory ensheathing cell (OEC) transplantation is a candidate cellular treatment approach for human spinal cord injury (SCI) due to their unique regenerative potential and autologous origin. The objective of this study was, through a meta-epidemiologic approach, (i) to assess the efficacy of OEC transplantation on locomotor recovery after traumatic experimental SCI and (ii) to estimate the likelihood of reporting bias and/or missing data. A study protocol was finalized before data collection. Embedded into a systematic review and meta-analysis, we conducted a literature research of databases including PubMed, EMBASE, and ISI Web of Science from 1949/01 to 2014/10 with no language restrictions, screened by two independent investigators. Studies were included if they assessed neurobehavioral improvement after traumatic experimental SCI, administrated no combined interventions, and reported the number of animals in the treatment and control group. Individual effect sizes were pooled using a random effects model. Details regarding the study design were extracted and impact of these on locomotor outcome was assessed by meta-regression. Missing data (reporting bias) was determined by Egger regression and Funnel-plotting. The primary study outcome assessed was improvement in locomotor function at the final time point of measurement. We included 49 studies (62 experiments, 1,164 animals) in the final analysis. The overall improvement in locomotor function after OEC transplantation, measured using the Basso, Beattie, and Bresnahan (BBB) score, was 20.3% (95% CI 17.8–29.5). One missing study was imputed by trim and fill analysis, suggesting only slight publication bias and reducing the overall effect to a 19.2% improvement of locomotor activity. Dose-response ratio supports neurobiological plausibility. Studies were assessed using a 9-point item quality score, resulting in a median score of 5 (interquartile range [IQR] 3–5). In conclusion, OEC transplantation exerts considerable beneficial effects on neurobehavioral recovery after traumatic experimental SCI. Publication bias was minimal and affirms the translational potential of efficacy, but safety cannot be adequately assessed. The data justify OECs as a cellular substrate to develop and optimize minimally invasive and safe cellular transplantation paradigms for the lesioned spinal cord embedded into state-of-the-art Phase I/II clinical trial design studies for human SCI.

This meta-analysis study examines the effects of transplanting olfactory ensheathing cells in rodents with experimental spinal cord injury, finding evidence for significant recovery and identifying aspects of the procedure that influence the effect size.

Spinal cord injury converts into a debilitating disease affecting millions of chronic patients worldwide. Despite increased molecular knowledge over the last decades, no causal pharmacological or cellular therapy has proven effective so far. Due to their unique regenerative capabilities and their autologous origin, olfactory ensheathing cells (OECs) constitute an appealing candidate for topical cell transplantation. In contrast to few and heterogeneous experimental reports of OEC transplantation after spinal cord injury in humans, a considerable number of preclinical studies have been conducted applying OEC transplantation in rodent models. We set out to conduct a systematic review and meta-analysis to assess preclinical efficacy of OEC transplantation. We detected a significant overall increase of functional neurological recovery in animals after OEC transplantation compared to the control group. This effect was not distorted by publication bias. We identified several specific hallmarks of the cell transplantation procedure that determine the effect size of the transplantation. Our findings delineate conditions for optimized OEC transplantation into lesioned spinal cords and its relevance for effective translation to human trials.

Spinal cord injury-induced immune deficiency syndrome enhances infection susceptibility dependent on lesion level

Pneumonia is the leading cause of death after acute spinal cord injury and is associated with poor neurological outcome. In contrast to the current understanding, attributing enhanced infection susceptibility solely to the patient's environment and motor dysfunction, we investigate whether a secondary functional neurogenic immune deficiency (spinal cord injury-induced immune deficiency syndrome, SCI-IDS) may account for the enhanced infection susceptibility. We applied a clinically relevant model of experimental induced pneumonia to investigate whether the systemic SCI-IDS is functional sufficient to cause pneumonia dependent on spinal cord injury lesion level and investigated whether findings are mirrored in a large prospective cohort study after human spinal cord injury. In a mouse model of inducible pneumonia, high thoracic lesions that interrupt sympathetic innervation to major immune organs, but not low thoracic lesions, significantly increased bacterial load in lungs. The ability to clear the bacterial load from the lung remained preserved in sham animals. Propagated immune susceptibility depended on injury of central pre-ganglionic but not peripheral postganglionic sympathetic innervation to the spleen. Thoracic spinal cord injury level was confirmed as an independent increased risk factor of pneumonia in patients after motor complete spinal cord injury (odds ratio = 1.35, P < 0.001) independently from mechanical ventilation and preserved sensory function by multiple regression analysis. We present evidence that spinal cord injury directly causes increased risk for bacterial infection in mice as well as in patients. Besides obvious motor and sensory paralysis, spinal cord injury also induces a functional SCI-IDS ('immune paralysis'), sufficient to propagate clinically relevant infection in an injury level dependent manner.

The paradox of chronic neuroinflammation, systemic immune suppression, autoimmunity after traumatic chronic spinal cord injury

During the transition from acute to chronic stages of recovery after spinal cord injury (SCI), there is an evolving state of immunologic dysfunction that exacerbates the problems associated with the more clinically obvious neurologic deficits. Since injury directly affects cells embedded within the "immune privileged/specialized" milieu of the spinal cord, maladaptive or inefficient responses are likely to occur. Collectively, these responses qualify as part of the continuum of "SCI disease" and are important therapeutic targets to improve neural repair and neurological outcome. Generic immune suppressive therapies have been largely unsuccessful, mostly because inflammation and immunity exert both beneficial (plasticity enhancing) and detrimental (e.g. glia- and neurodegenerative; secondary damage) effects and these functions change over time. Moreover, "compartimentalized" investigations, limited to only intraspinal inflammation and associated cellular or molecular changes in the spinal cord, neglect the reality that the structure and function of the CNS are influenced by systemic immune challenges and that the immune system is 'hardwired' into the nervous system. Here, we consider this interplay during the progression from acute to chronic SCI. Specifically, we survey impaired/non-resolving intraspinal inflammation and the paradox of systemic inflammatory responses in the context of ongoing chronic immune suppression and autoimmunity. The concepts of systemic inflammatory response syndrome (SIRS), compensatory anti-inflammatory response syndrome (CARS) and "neurogenic" spinal cord injury-induced immune depression syndrome (SCI-IDS) are discussed as determinants of impaired "host-defense" and trauma-induced autoimmunity.

The SCIentinel study--prospective multicenter study to define the spinal cord injury-induced immune depression syndrome (SCI-IDS)--study protocol and interim feasibility data

Background

Infections are the leading cause of death in the acute phase following spinal cord injury and qualify as independent risk factor for poor neurological outcome (“disease modifying factor”). The enhanced susceptibility for infections is not stringently explained by the increased risk of aspiration in tetraplegic patients, neurogenic bladder dysfunction, or by high-dose methylprednisolone treatment. Experimental and clinical pilot data suggest that spinal cord injury disrupts the balanced interplay between the central nervous system and the immune system. The primary hypothesis is that the Spinal Cord Injury-induced Immune Depression Syndrome (SCI-IDS) is 'neurogenic’ including deactivation of adaptive and innate immunity with decreased HLA-DR expression on monocytes as a key surrogate parameter. Secondary hypotheses are that the Immune Depression Syndrome is i) injury level- and ii) severity-dependent, iii) triggers transient lymphopenia, and iv) causes qualitative functional leukocyte deficits, which may endure the post-acute phase after spinal cord injury.

Methods/Design

SCIentinel is a prospective, international, multicenter study aiming to recruit about 118 patients with acute spinal cord injury or control patients with acute vertebral fracture without neurological deficits scheduled for spinal surgery. The assessment points are: i) <31 hours, ii) 31–55 hours, iii) 7 days, iv) 14 days, and v) 10 weeks post-trauma. Assessment includes infections, concomitant injury, medication and neurological classification using American Spinal Injury Association impairment scale (AIS) and neurological level. Laboratory analyses comprise haematological profiling, immunophenotyping, including HLA-DR expression on monocytes, cytokines and gene expression of immune modulators. We provide an administrative interim analysis of the recruitment schedule of the trial.

Discussion

The objectives are to characterize the dysfunction of the innate and adaptive immune system after spinal cord injury and to explore its proposed 'neurogenic’ origin by analyzing its correlation with lesion height and severity. The trial protocol considers difficulties of enrolment in an acute setting, and loss to follow up. The administrative interim analysis confirmed the feasibility of the protocol. Better understanding of the SCI-IDS is crucial to reduce co-morbidities and thereby to attenuate the impact of disease modifying factors to protect neurological “outcome at risk”. This putatively results in improved spinal cord injury medical care.

Trial registration

DRKS-ID: DRKS00000122 (German Clinical Trials Registry)

Functional neurological recovery after spinal cord injury is impaired in patients with infections

Infections are a common threat to patients after spinal cord injury. Furthermore, infections might propagate neuronal death, and consequently contribute to the restriction of neurological recovery. We investigated the association of infections (i.e. pneumonia and/or postoperative wound infections) with functional neurological outcome after acute severe traumatic spinal cord injury. We screened data sets of 24 762 patients enrolled in a prospective cohort study (National Spinal Cord Injury Database, Birmingham, AL, USA). Patients were assessed according to the ASIA classification. ASIA impairment scale-classified A and B patients recruited within 24 h post-trauma (n = 1436) were selected as being a major recruitment population for interventional trials. Patients with documented pneumonia and/or postoperative wound infections (n = 581) were compared with control subjects (non-documented infections, n = 855). The functional neurological outcome parameters (i) upward ASIA impairment scale conversions; (ii) gain of ASIA motor scores; and (iii) gain of motor and sensory levels were consecutively analysed over time up to 1 year after spinal cord injury. The group with pneumonia and/or postoperative wound infections revealed less ASIA impairment scale upward conversions after 1 year than the control group (ASIA impairment scale A: 17.2 versus 23.9%, P = 0.03; ASIA impairment scale B: 57.1 versus 74.7%, P = 0.009). ASIA motor score gain [median (interquartile range)] was lower in patients with infections [ASIA impairment scale A: 8 (4-12) versus 10 (5-17), P = 0.01; ASIA impairment scale B: 19.5 (8-53.5) versus 42 (20.5-64), P = 0.03)]. Analysis of acquired motor/sensory levels supported these findings. In ASIA impairment scale A patients, the gain in motor levels (21.7 versus 33.3%, P = 0.04) and sensory levels (24.4 versus 38 of 102, 37.3%, P = 0.03) was significantly lower in the group with pneumonia and/or postoperative wound infections than in the control group. Multiple regression analysis identified pneumonia and/or postoperative wound infections as independent risk factors for impaired ASIA impairment scale upward conversion (odds ratio: 1.89, 95% confidence interval: 1.36-2.63, P < 0.0005) or lower gain in ASIA motor score (regression coefficient: -8.21, 95% confidence interval: -12.29 to -4.14, P < 0.0005). Infections associated with spinal cord injury, such as pneumonia and/or postoperative wound infections, qualify as independent risk factors for poor neurological outcome after motor complete spinal cord injury. Infections constitute a clinically relevant target for protecting the limited endogenous functional regeneration capacity. Upcoming interventional trials might gain in efficacy with improved patient stratification and might benefit from complementary protection of the intrinsic recovery potential after spinal cord injury.

Small-molecule-induced Rho-inhibition: NSAIDs after spinal cord injury

Limited axonal plasticity within the central nervous system (CNS) is a major restriction for functional recovery after CNS injury. The small GTPase RhoA is a key molecule of the converging downstream cascade that leads to the inhibition of axonal re-growth. The Rho-pathway integrates growth inhibitory signals derived from extracellular cues, such as chondroitin sulfate proteoglycans, Nogo-A, myelin-associated glycoprotein, oligodendrocyte-myelin glycoprotein, Ephrins and repulsive guidance molecule-A, into the damaged axon. Consequently, the activation of RhoA results in growth cone collapse and finally outgrowth failure. In turn, the inhibition of RhoA-activation blinds the injured axon to its growth inhibitory environment resulting in enhanced axonal sprouting and plasticity. This has been demonstrated in various CNS-injury models for direct RhoA-inhibition and for downstream/upstream blockade of the RhoA-associated pathway. In addition, RhoA-inhibition reduces apoptotic cell death and secondary damage and improves locomotor recovery in clinically relevant models after experimental spinal cord injury (SCI). Unexpectedly, a subset of "small molecules" from the group of non-steroid anti-inflammatory drugs, particularly the FDA-approved ibuprofen, has recently been identified as (1) inhibiting RhoA-activation, (2) enhancing axonal sprouting/regeneration, (3) protecting "tissue at risk" (neuroprotection) and (4) improving motor recovery confined to realistic therapeutical time-frames in clinically relevant SCI models. Here, we survey the effect of small-molecule-induced RhoA-inhibition on axonal plasticity and neurofunctional outcome in CNS injury paradigms. Furthermore, we discuss the body of preclinical evidence for a possible clinical translation with a focus on ibuprofen and illustrate putative risks and benefits for the treatment of acute SCI.

Spinal cord injury induces differential expression of the profibrotic semaphorin 7A in the developing and mature glial scar

Semaphorin 7A (Sema7A) is involved in the formation of the central nervous system during development by operating axon guidance and neuronal migration. We investigated the expression of the TGFβ-inducible Sema7A following spinal cord injury (SCI). After SCI, Sema7A(+) cells accumulated specifically in lesion areas resulting in significantly enhanced Sema7A expression at the injury site (P < 0.0001). During the first days lesional Sema7A expression was confined to neurons, ballooned neurite fibers/retraction bulbs, and endothelial cells. At day 7, we observed Sema7A expression by components of the glial scar, such as reactive astrocytes and pronounced extracellular Sema7A deposition. In the direct perilesional rim, Sema7A(+) astrocytes coexpressed the activation-associated intermediate filament vimentin. In the injured spinal cord, numbers of Sema7A(+) cells reached maximum levels at day 14. The restricted accumulation of Sema7A(+) reactive astrocytes and Sema7A deposition in fibronectin(+) extracellular matrix territories suggests a participation of the fibrostimulatory Sema7A in the developing and maturating scar following SCI. In addition, Sema7A appears to be marker a for astrocyte activation.

Non-resolving aspects of acute inflammation after spinal cord injury (SCI): indices and resolution plateau

Inflammatory resolution is an active, highly regulated process already encoded at the onset of inflammation and required to prevent the transition into chronic inflammation associated with spreading of tissue injury and exacerbated scarring. We introduce objective, quantitative measurements [resolution indices (R(i) ) and resolution plateau (R(P) )] to characterize inflammatory resolution and to determine the persistence ("dwell time") of differential leukocyte subpopulations at the lesion site after acute experimental spinal cord injury (SCI). The cell type-specific resolution interval R(i) (time between maximum cell numbers and the point when they are reduced to 50%) ranges from 1.2 days for neutrophils, 1.5 days for T lymphocytes, to 55 days for microglia/macrophages. As the resolution interval neglects exiting cell trafficking in the later period of resolution (49%-0% of lesional cells), we introduced the R(P) , a marker for the persisting, chronified leukocyte subsets, which are likely to participate in late degeneration and non-resolving inflammation. Here, we identify the acute inflammatory response in central nervous system (CNS) lesions as partly non self-limiting. Both extended resolution intervals (reduced leukocyte clearance) and elevated plateaus (permanent lesional cell numbers) provide quantitative measures to characterize residual, sustained inflammation and define cognate timeframes of impaired resolution after acute SCI.

Impaired insulin sensitivity as an underlying mechanism linking hepatitis C and posttransplant diabetes mellitus in kidney recipients

Aim of this study was to investigate the mechanism/s associating hepatitis C virus (HCV) infection and posttransplant diabetes mellitus in kidney recipients. Twenty HCV-positive and 22 HCV-negative kidney recipients, 14 HCV-positive nontransplant patients and 24 HCV-negative nontransplant (healthy) subjects were analyzed. A 3-h intravenous glucose tolerance test was performed; peripheral insulin sensitivity was assessed by minimal modeling. Pancreatic insulin secretion, hepatic insulin uptake, pancreatic antibodies and proinflammatory cytokines in serum (tumor necrosis factor-alpha, intereukin-6, high-sensitive C-reactive protein) were also assessed. HCV-positive recipients showed a significantly lower insulin sensitivity as compared to HCV-negative recipients (3.0 +/- 2.1 vs. 4.9 +/- 3.0 min(-1).microU.mL(- 1).10(4), p = 0.02), however, insulin secretion and hepatic insulin uptake were not significantly different. Pancreatic antibodies were negative in all. HCV status was an independent predictor of impaired insulin sensitivity (multivariate analysis, p = 0.008). The decrease of insulin sensitivity due to HCV was comparable for transplant and non-transplant subjects. No significant correlation was found between any of the cytokines and insulin sensitivity. Our results suggest that impaired peripheral insulin sensitivity is associated with HCV infection irrespective of the transplant status, and is the most likely pathogenic mechanism involved in the development of type 2 diabetes mellitus associated with HCV infection.