The effects of gender on clinical and neurological outcomes after acute cervical spinal cord injury

Potential role of hippocampal neurogenesis in spinal cord injury induced post-trauma depression

It has been reported both in clinic and rodent models that beyond spinal cord injury directly induced symptoms, such as paralysis, neuropathic pain, bladder/bowel dysfunction, and loss of sexual function, there are a variety of secondary complications, including memory loss, cognitive decline, depression, and Alzheimer's disease. The large-scale longitudinal population-based studies indicate that post-trauma depression is highly prevalent in spinal cord injury patients. Yet, few basic studies have been conducted to address the potential molecular mechanisms. One of possible factors underlying the depression is the reduction of adult hippocampal neurogenesis which may come from less physical activity, social isolation, chronic pain, and elevated neuroinflammation after spinal cord injury. However, there is no clear consensus yet. In this review, we will first summarize the alteration of hippocampal neurogenesis post-spinal cord injury. Then, we will discuss possible mechanisms underlie this important spinal cord injury consequence. Finally, we will outline the potential therapeutic options aimed at enhancing hippocampal neurogenesis to ameliorate depression.

The secondary injury cascade after spinal cord injury: an analysis of local cytokine/chemokine regulation

JOURNAL/nrgr/04.03/01300535-202406000-00035/inline-graphic1/v/2023-10-30T152229Z/r/image-tiff

After spinal cord injury, there is an extensive infiltration of immune cells, which exacerbates the injury and leads to further neural degeneration. Therefore, a major aim of current research involves targeting the immune response as a treatment for spinal cord injury. Although much research has been performed analyzing the complex inflammatory process following spinal cord injury, there remain major discrepancies within previous literature regarding the timeline of local cytokine regulation. The objectives of this study were to establish an overview of the timeline of cytokine regulation for 2 weeks after spinal cord injury, identify sexual dimorphisms in terms of cytokine levels, and determine local cytokines that significantly change based on the severity of spinal cord injury. Rats were inflicted with either a mild contusion, moderate contusion, severe contusion, or complete transection, 7 mm of spinal cord centered on the injury was harvested at varying times post-injury, and tissue homogenates were analyzed with a Cytokine/Chemokine 27-Plex assay. Results demonstrated pro-inflammatory cytokines including tumor necrosis factor α, interleukin-1β, and interleukin-6 were all upregulated after spinal cord injury, but returned to uninjured levels within approximately 24 hours post-injury, while chemokines including monocyte chemoattractant protein-1 remained upregulated for days post-injury. In contrast, several anti-inflammatory cytokines and growth factors including interleukin-10 and vascular endothelial growth factor were downregulated by 7 days post-injury. After spinal cord injury, tissue inhibitor of metalloproteinase-1, which specifically affects astrocytes involved in glial scar development, increased more than all other cytokines tested, reaching 26.9-fold higher than uninjured rats. After a mild injury, 11 cytokines demonstrated sexual dimorphisms; however, after a severe contusion only leptin levels were different between female and male rats. In conclusion, pro-inflammatory cytokines initiate the inflammatory process and return to baseline within hours post-injury, chemokines continue to recruit immune cells for days post-injury, while anti-inflammatory cytokines are downregulated by a week post-injury, and sexual dimorphisms observed after mild injury subsided with more severe injuries. Results from this work define critical chemokines that influence immune cell infiltration and important cytokines involved in glial scar development after spinal cord injury, which are essential for researchers developing treatments targeting secondary damage after spinal cord injury.

A Perspective on Hormonal Contraception Usage in Central Nervous System Injury

Naturally occurring life stages in women are associated with changes in the milieu of endogenous ovarian hormones. Women of childbearing age may be exposed to exogenous ovarian hormone(s) because of their use of varying combinations of estrogen and progesterone hormones-containing oral contraceptives (OC; also known as "the pill"). If women have central nervous system (CNS) injury such as spinal cord injury (SCI) and traumatic brain injury (TBI) during their childbearing age, they are likely to retain their reproductive capabilities and may use OC. Many deleterious side effects of long-term OC use have been reported, such as aberrant blood clotting and endothelial dysfunction that consequently increase the risk of myocardial infarction, venous thromboembolism, and ischemic brain injury. Although controversial, studies have suggested that OC use is associated with neuropsychiatric ramifications, including uncontrollable mood swings and poorer cognitive performance. Our understanding about how the combination of endogenous hormones and OC-conferred exogenous hormones affect outcomes after CNS injuries remains limited. Therefore, understanding the impact of OC use on CNS injury outcomes needs further investigation to reveal underlying mechanisms, promote reporting in clinical or epidemiological studies, and raise awareness of possible compounded consequences. The goal of the current review is to discuss the impacts of CNS injury on endogenous ovarian hormones and vice-versa, as well as the putative consequences of exogenous ovarian hormones (OC) on the CNS to identify potential gaps in our knowledge to consider for future laboratory, epidemiological, and clinical studies.

Neuropathic pain development and maintenance and its association with motor recovery after cervical spinal cord injury

BACKGROUND

In our published randomized controlled trial, we revealed that patients with acute ASIA Grade C incomplete cervical spinal cord injury (SCI) who underwent early surgery (within 24 h post-injury) had accelerated motor recovery at six months than those with delayed surgery (>2 weeks post-injury); however, neuropathic pain (NeP) worsened regardless of surgery timing. Here, we conducted post-hoc analyses to intensively assess NeP development and maintenance.

METHODS

Of 44 patients (median 64.5 years; three female; early intervention, n = 26), NeP was categorized into at-level and below-level pain and evaluated at  two weeks and one year after injury using the Neuropathic Pain Symptom Inventory (NPSI). We compared the two groups based on background characteristics. A mixed-design analysis of variance with sex as a covariate was conducted to analyze motor recovery and Health-related quality of life (HRQOL) in groups with severe (NPSI ≥ 10) or mild (NPSI < 10) pain.

RESULTS

Upper and lower limb motor impairments were comparable between both groups regardless of pain severity. Severe at-level pain remained stable and worsened at one year than mild at-level pain; however, the upper- and lower-limb motor scores and HRQOL had comparable recovery. Background characteristics did not affect severity or time course of NeP. Patients with severe below-level pain demonstrated slower lower-limb motor recovery than those with mild below-level pain, whereas HRQOL improved regardless of pain severity.

CONCLUSIONS

Both at-level and below-level NeP developed and persisted relatively early in the course of traumatic SCI with incomplete motor paralysis; their severities worsened over time or remained severe since onset.

Sex disparities in adverse outcomes after surgically managed isolated traumatic spinal injury

BACKGROUND

Traumatic spinal injury (TSI) encompasses a wide range of injuries affecting the spinal cord, nerve roots, bones, and soft tissues that result in pain, impaired mobility, paralysis, and death. There is some evidence suggesting that women may have different physiological responses to traumatic injury compared to men; therefore, this study aimed to investigate if there are any associations between sex and adverse outcomes following surgically managed isolated TSI.

METHODS

Using the 2013-2019 TQIP database, all adult patients with isolated TSI, defined as a spine AIS ≥ 2 with an AIS ≤ 1 in all other body regions, resulting from blunt force trauma requiring spinal surgery, were eligible for inclusion in the study. The association between the sex and in-hospital mortality as well as cardiopulmonary and venothromboembolic complications was determined by calculating the risk ratio (RR) after adjusting for potential confounding using inverse probability weighting.

RESULTS

A total of 43,756 patients were included. After adjusting for potential confounders, female sex was associated with a 37% lower risk of in-hospital mortality [adjusted RR (95% CI): 0.63 (0.57-0.69), p < 0.001], a 27% lower risk of myocardial infarction [adjusted RR (95% CI): 0.73 (0.56-0.95), p = 0.021], a 37% lower risk of cardiac arrest [adjusted RR (95% CI): 0.63 (0.55-0.72), p < 0.001], a 34% lower risk of deep vein thrombosis [adjusted RR (95% CI): 0.66 (0.59-0.74), p < 0.001], a 45% lower risk of pulmonary embolism [adjusted RR (95% CI): 0.55 (0.46-0.65), p < 0.001], a 36% lower risk of acute respiratory distress syndrome [adjusted RR (95% CI): 0.64 (0.54-0.76), p < 0.001], a 34% lower risk of pneumonia [adjusted RR (95% CI): 0.66 (0.60-0.72), p < 0.001], and a 22% lower risk of surgical site infection [adjusted RR (95% CI): 0.78 (0.62-0.98), p < 0.032], compared to male sex.

CONCLUSION

Female sex is associated with a significantly decreased risk of in-hospital mortality as well as cardiopulmonary and venothromboembolic complications following surgical management of traumatic spinal injuries. Further studies are needed to elucidate the cause of these differences.

Progress Report on the Spinal Cord Rehabilitation Research Initiatives Based on Registered Clinical Studies From 2000 to 2022

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CME OBJECTIVES

Upon completion of this article, the reader should be able to: (1) Identify the most common trends and features of research studies on spinal cord rehabilitation, which were registered in the ClinicalTrials.gov Website between 2000 and 2022; (2) Discuss the main limitations of research on spinal cord rehabilitation, based on the protocols published on the ClinicalTrials.gov Website; and (3) Recognize important knowledge gaps in clinical studies on spinal cord rehabilitation that were registered in the ClinicalTrials.gov Website.

LEVEL

Advanced.

ACCREDITATION

The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s) ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Sex-Related Discrepancies in the Access to Optimal Care and Outcomes After Traumatic Spinal Cord Injury: A Retrospective Cohort Study Using Data From a Canadian Registry

OBJECTIVE

To compare males and females who were stratified into subgroups corresponding to premenopausal, perimenopausal, and postmenopausal ages, regarding access to optimal care and their outcomes after traumatic spinal cord injury (tSCI).

STUDY DESIGN

Retrospective cohort study.

SETTING

Eighteen acute care centers and 13 rehabilitation facilities across Canada.

PARTICIPANTS

This study included 5571 individuals with tSCI at C1-L2 who were enrolled in the Rick Hansen Spinal Cord Injury Registry from July 2004 to September 2019 (N=5571). Females were compared with males in the younger (aged ≤40 years), middle-aged (ages 41-50), and older (aged >50 years) subgroups.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Females were compared with males in each subgroup with regard to their demographic data, pre-existing comorbidities, injury characteristics, management choices, access to optimal care, and clinical, neurologic, and functional outcomes after tSCI.

RESULTS

In the younger subgroups, females (n=408) were significantly younger, had a greater proportion of aboriginals and transportation-related tSCIs, underwent surgical treatment more often, and had a greater sensory score change than males (n=1613). In the middle-aged subgroups, females (n=174) had a greater proportion of high-thoracic tSCIs than males (n=666). In the older subgroups, females (n=660) were significantly older, had more fall-related and less severe tSCIs, had a shorter stay at the rehabilitation center, had less spasticity, and were discharged home less often than males (n=2050).

CONCLUSIONS

The results of this study suggest some sex-related differences in individuals' demographics and injury characteristics, but fewer discrepancies between females and males regarding their access to optimal care and outcomes after tSCI. Overall, future clinical trials could consider inclusion of males and females of all age groups to enhance recruitment and augment generalizability.

Neuroprotective effects of lovastatin against traumatic spinal cord injury in rats

BACKGROUND

Lovastatin, as a drug of statins subgroup, has been conceptualized to have anti-inflammatory, antioxidant, and anti-apoptotic properties. Accordingly, the present study aimed to investigate the neuroprotective ramification of lovastatin on spinal cord injury (SCI).

MATERIAL AND METHODS

Seventy-five female adult Wistar rats were divided into five groups (n = 15). In addition to non-treated (Control group) and laminectomy alone (Sham group), SCI animals were randomly assigned to non-treated spinal cord injury (SCI group), treated with 2 mg/kg of lovastatin (Lova 2 group), and treated with 5 mg/kg of lovastatin (Lova 5 group). At the end of the study, to evaluate the treatments, MDA, CAT, SOD, and GSH factors were evaluated biochemically, apoptosis and gliosis were assessed by immunohistochemical while measuring caspase-3 and GFAP antibodies, and inflammation was estimated by examining the expression of IL-10, TNF-α, and IL-1β genes. The stereological method was used to appraise the total volume of the spinal cord at the site of injury, the volume of the central cavity created, and the density of neurons and glial cells in the traumatic area. In addition, Basso-Beattie-Bresnehan (BBB) and narrow beam test (NBT) were utilized to rate neurological functions.

RESULTS

Our results exposed the fact that biochemical factors (except MDA), stereological parameters, and neurological functions were significantly ameliorated in both lovastatin-treated groups, especially in Lova 5 ones, compared to the SCI group. The expression of the IL-10 gene was significantly upregulated in both lovastatin-treated groups compared to the SCI group and was considerably heighten in Lova 5 group. Expression of TNF-α and IL-1β, as well as the rate of apoptosis and GFAP positive cells significantly decreased in both lovastatin treated groups compared to the SCI group, and it was more pronounced in the Lova 5 ones.

CONCLUSION

Overall, using lovastatin, especially at a dose of 5 mg/kg, has a dramatic neuroprotective impact on SCI treatment.

Extracellular Matrix and Oxidative Stress Following Traumatic Spinal Cord Injury: Physiological and Pathophysiological Roles and Opportunities for Therapeutic Intervention

Significance: Traumatic spinal cord injury (SCI) causes significant disruption to neuronal, glial, vascular, and extracellular elements. The spinal cord extracellular matrix (ECM) comprises structural and communication proteins that are involved in reparative and regenerative processes after SCI. In the healthy spinal cord, the ECM helps maintain spinal cord homeostasis. After SCI, the damaged ECM limits plasticity and contributes to inflammation through the expression of damage-associated molecules such as proteoglycans. Recent Advances: Considerable insights have been gained by characterizing the origins of the gliotic and fibrotic scars, which not only reduce the spread of injury but also limit neuroregeneration. These properties likely limit the success of therapies used to treat patients with SCI. The ECM, which is a major contributor to the scars and normal physiological functions of the spinal cord, represents an exciting therapeutic target to enhance recovery post-SCI. Critical Issue: Various ECM-based preclinical therapies have been developed. These include disrupting scar components, inhibiting activity of ECM metalloproteinases, and maintaining iron homeostasis. Biomaterials have also been explored. However, the majority of these treatments have not experienced successful clinical translation. This could be due to the ECM and scars' polarizing roles. Future Directions: This review surveys the complexity involved in spinal ECM modifications, discusses new ECM-based combinatorial strategies, and explores the biomaterials evaluated in clinical trials, which hope to introduce new treatments that enhance recovery after SCI. These topics will incorporate oxidative species, which are both beneficial and harmful in reparative and regenerative processes after SCI, and not often assessed in pertinent literature. Antioxid. Redox Signal. 37, 184-207.

Astrocytic Nrf2 expression protects spinal cord from oxidative stress following spinal cord injury in a male mouse model

BACKGROUND

Spinal cord injury (SCI) induces a multitude of deleterious processes, including neuroinflammation and oxidative stress (OS) which contributed to neuronal damage and demyelination. Recent studies have suggested that increased formation of reactive oxygen species (ROS) and the consequent OS are critical events associated with SCI. However, there is still little information regarding the impact of these events on SCI. Astrocytes are key regulators of oxidative homeostasis in the CNS and astrocytic antioxidant responses promote the clearance of oxidants produced by neurons. Therefore, dysregulation of astrocyte physiology might largely contribute to oxidative damage. Nuclear factor erythroid 2-related factor 2 (Nrf2) is the main transcriptional regulator of cellular anti-oxidative stress responses.

METHODS

In the current study, we hypothesized that astrocytic activation of Nrf2 protects the spinal cord post injury via suppression of neuroinflammation. Thus, using mice line with a GFAP-specific kelch-like ECH-associated protein 1 (Keap1)-deletion, we induced a hyperactivation of Nrf2 in astrocytes and further its effects on SCI outcomes. SCI-induction was performed in mice using the Infinite Horizon Spinal Cord Impactor with a force of 60 kdyn. To assess the quantitative pattern of Nrf2/ARE-activation, we included transgenic ARE-Luc mice. Data were analyzed with GraphPad Prism 8 (GraphPad Software Inc., San Diego, CA, USA). Brown-Forsythe test was performed to test for equal variances and normal distribution was tested with Shapiro-Wilk.

RESULTS

In ARE-Luc mice, a significant induction of luciferase-activity was observed as early as 1 day post-injury, indicating a functional role of Nrf2-activity at the epicenter of SCI. Furthermore, SCI induced loss of neurons and oligodendrocytes, demyelination and inflammation in wild type mice. The loss of myelin and oligodendrocytes was clearly reduced in Keap1 KO mice. In addition, Keap-1 KO mice showed a significantly better locomotor function and lower neuroinflammation responses compared to wild type mice.

CONCLUSIONS

In summary, our in vivo bioluminescence data showed Nrf2-ARE activation during primary phase of SCI. Furthermore, we found that cell specific hyperactivation of Nrf2 was sufficient to protect the spinal cord against injury which indicate a promising therapeutic approach for SCI-treatment.

A Scoping Review of Registered Clinical Studies on Management of Individuals With Acute Spinal Cord Injury (2000-2020): Trends and Characteristics of the Research Initiatives

ABSTRACT

This scoping review examined the current trends and characteristics of the clinical research initiatives on the management of acute spinal cord injury. This review included all clinical studies on the acute treatment of spinal cord injury that were registered in the ClinicalTrials.gov website from February 2000 to December 2020. The search strategy combined the terms "acute spinal cord injury" and "treatment." There has been a gradual increase in the number of registered clinical studies on acute treatment of spinal cord injury over the past two decades. Of the 116 studies, there were 103 interventional studies, 12 observational studies, and 1 registry. While 115 clinical studies recruited male and female participants, most of the registered clinical studies included only adults with an upper age limit after spinal cord injury. Most of the registered clinical studies were interventional studies led by single institutions in North America (n = 70), Europe (n = 29), and Asia (n = 15). Most of the research initiatives were interventional studies on new therapies for management of individuals with spinal cord injury (n = 91). In conclusion, the results of this scoping review suggest that although there has been an increase in the amount and diversity of the research initiatives on treatment of acute spinal cord injury over the past two decades, their generalizability remains relatively limited.

Osteopenia in a Mouse Model of Spinal Cord Injury: Effects of Age, Sex and Motor Function

Simple Summary

In the first two years following spinal cord injury, people lose up to 50% of bone below the injury. This injury-induced bone loss significantly affects rehabilitation and leaves people vulnerable to fractures and post-fracture complications, including lung and urinary tract infections, blood clots in the veins, and depression. Unfortunately, little is known about the factors driving this bone loss. In fact, even though we know that injury, age, and sex independently increase bone loss, there have been no studies looking at the cumulative effects of these variables. People with spinal injury are aging, and the age at which injuries occur is increasing. It is essential to know whether these factors together will further compromise bone. To examine this, we assessed bone loss in young and old, male and female mice after spinal injury. As expected, we found that aging alone decreased motor activity and bone volume. Spinal injury also reduced bone volume, but it did not worsen the effects of age. Instead, injury effects appeared related to reduced rearing activity. The data suggest that although partial weight-bearing does not reduce bone loss after spinal cord injury, therapies that put full weight on the legs may be clinically effective.

Abstract

After spinal cord injury (SCI), 80% of individuals are diagnosed with osteopenia or osteoporosis. The dramatic loss of bone after SCI increases the potential for fractures 100-fold, with post-fracture complications occurring in 54% of cases. With the age of new SCI injuries increasing, we hypothesized that a SCI-induced reduction in weight bearing could further exacerbate age-induced bone loss. To test this, young (2–3 months) and old (20–30 months) male and female mice were given a moderate spinal contusion injury (T9–T10), and recovery was assessed for 28 days (BMS, rearing counts, distance traveled). Tibial trabecular bone volume was measured after 28 days with ex vivo microCT. While BMS scores did not differ across groups, older subjects travelled less in the open field and there was a decrease in rearing with age and SCI. As expected, aging decreased trabecular bone volume and cortical thickness in both old male and female mice. SCI alone also reduced trabecular bone volume in young mice, but did not have an additional effect beyond the age-dependent decrease in trabecular and cortical bone volume seen in both sexes. Interestingly, both rearing and total activity correlated with decreased bone volume. These data underscore the importance of load and use on bone mass. While partial weight-bearing does not stabilize/reverse bone loss in humans, our data suggest that therapies that simulate complete loading may be effective after SCI.

Demographic Predictors of Treatment and Complications for Spinal Disorders: Part 2, Lumbar Spine Trauma

Objective

To study the impact of demographic factors on management of traumatic injury to the lumbar spine and postoperative complication rates.

Methods

Data was obtained from the National Inpatient Sample (NIS) between 2010–2014. International Classification of Diseases, 9th revision, Clinical Modification codes identified patients diagnosed with lumbar fractures or dislocations due to trauma. A series of multivariate regression models determined whether demographic variables predicted rates of complication and revision surgery.

Results

A total of 38,249 patients were identified. Female patients were less likely to receive surgery and to receive a fusion when undergoing surgery, had higher complication rates, and more likely to undergo revision surgery. Medicare and Medicaid patients were less likely to receive surgical management for lumbar spine trauma and less likely to receive a fusion when operated on. Additionally, we found significant differences in surgical management and postoperative complication rates based on race, insurance type, hospital teaching status, and geography.

Conclusion

Substantial differences in the surgical management of traumatic injury to the lumbar spine, including postoperative complications, among individuals of demographic factors such as age, sex, race, primary insurance, hospital teaching status, and geographic region suggest the need for further studies to understand how patient demographics influence management and complications for traumatic injury to the lumbar spine.

Hemorrhage and Locomotor Deficits Induced by Pain Input after Spinal Cord Injury Are Partially Mediated by Changes in Hemodynamics

Nociceptive input diminishes recovery and increases lesion area after a spinal cord injury (SCI). Recent work has linked these effects to the expansion of hemorrhage at the site of injury. The current article examines whether these adverse effects are linked to a pain-induced rise in blood pressure (BP) and/or flow. Male rats with a low-thoracic SCI were treated with noxious input (electrical stimulation [shock] or capsaicin) soon after injury. Locomotor recovery and BP were assessed throughout. Tissues were collected 3 h, 24 h, or 21 days later. Both electrical stimulation and capsaicin undermined locomotor function and increased the area of hemorrhage. Changes in BP/flow varied depending on type of noxious input, with only shock producing changes in BP. Providing behavioral control over the termination of noxious stimulation attenuated the rise in BP and hemorrhage. Pretreatment with the α-1 adrenergic receptor inverse agonist, prazosin, reduced the stimulation-induced rise in BP and hemorrhage. Prazosin also attenuated the adverse effect that noxious stimulation has on long-term recovery. Administration of the adrenergic agonist, norepinephrine 1 day after injury induced an increase in BP and disrupted locomotor function, but had little effect on hemorrhage. Further, inducing a rise in BP/flow using norepinephrine undermined long-term recovery and increased tissue loss. Mediational analyses suggest that the pain-induced rise in blood flow may foster hemorrhage after SCI. Increased BP appears to act through an independent process to adversely affect locomotor performance, tissue sparing, and long-term recovery.

Characterizing Natural Recovery after Traumatic Spinal Cord Injury

The predominant tool used to predict outcomes after traumatic spinal cord injury (SCI) is the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), in association with the American Spinal Injury Association (ASIA) Impairment Scale (AIS). These measures have evolved based on analyses of large amounts of longitudinal neurological recovery data published in numerous separate studies. This article reviews and synthesizes published data on neurological recovery from multiple sources, only utilizing data in which the sacral sparing definition was applied for determination of completeness. Conversion from a complete to incomplete injury is more common in tetraplegia than paraplegia. The majority of AIS conversion and motor recovery occurs within the first 6-9 months, with the most rapid rate of motor recovery occurring in the first three months after injury. Motor score changes, as well as recovery of motor levels, are described with the initial strength of muscles as well as the levels of the motor zone of partial preservation influencing the prognosis. Total motor recovery is greater for patients with initial AIS B than AIS A, and greater after initial AIS C than with motor complete injuries. Older age has a negative impact on neurological and functional recovery after SCI; however, the specific age (whether >50 or >65 years) and underlying reasons for this impact are unclear. Penetrating injury is more likely to lead to a classification of a neurological complete injury compared with blunt trauma and reduces the likelihood of AIS conversion at one year. There are insufficient data to support gender having a major effect on neurological recovery after SCI.

Effects on Outcomes of Hyperglycemia in the Hyperacute Stage after Acute Traumatic Spinal Cord Injury

Hyperglycemia has adverse effects on neuronal recovery after brain injury, but its effects after spinal cord injury (SCI) are understudied. This retrospective cohort study examined the potential effects on outcomes of hyperglycemia in the hyperacute stage after acute traumatic SCI. This study included all individuals enrolled in the National Acute Spinal Cord Injury Study 3 (NASCIS-3). Glycemic levels at 24 h, at 48 h, and at day 7 after acute SCI were examined as potential determinants of survival, neurological outcomes (using NASCIS motor, sensory, and pain scores), and functional outcome (using the Functional Independence Measure [FIM]) within the first year post-SCI. Hyperglycemia was defined using two thresholds (140 mg/dL and 180 mg/dL). Study subjects were 76 females and 423 males with an overall mean age of 36 years who sustained mostly cervical SCI due to motor vehicle accidents or falls. Hyperglycemia diagnosed at day 7 post-injury was associated with significantly greater mortality rates post-SCI. Among the survivors, hyperglycemia during the hyperacute stage was not significantly correlated with neurological recovery post-SCI. Hyperglycemia persistent until day 7 was significantly correlated with lower functional scores post-SCI. These results suggest that hyperglycemia at day 7 is correlated with greater mortality rates within the first year post-SCI. Although hyperglycemia during the hyperacute stage was not associated with neurological recovery, hyperglycemia at day 7 may adversely affect functional recovery within the first year post-SCI. Future investigations are needed to determine the optimal glycemic target in the management of patients with SCI.

Endocrine Therapy for the Functional Recovery of Spinal Cord Injury

Spinal cord injury (SCI) is a major cause of physical disability and leads to patient dissatisfaction with their quality of life. Patients with SCI usually exhibit severe clinical symptoms, including sensory and motor dysfunction below the injured levels, paraplegia, quadriplegia and urinary retention, which can exacerbate the substantial medical and social burdens. The major pathological change observed in SCI is inflammatory reaction, which induces demyelination, axonal degeneration, and the apoptosis and necrosis of neurons. Traditional medical treatments are mainly focused on the recovery of motor function and prevention of complications. To date, numerous studies have been conducted to explore the cellular and molecular mechanism of SCI and have proposed lots of effective treatments, but the clinical applications are still limited due to the complex pathogenesis and poor prognosis after SCI. Endocrine hormones are kinds of molecules that are synthesized by specialized endocrine organs and can participate in the regulation of multiple physiological activities, and their protective effects on several disorders have been widely discussed. In addition, many studies have identified that endocrine hormones can promote nerve regeneration and functional recovery in individuals with central nervous system diseases. Therefore, studies investigating the clinical applications of endocrine hormones as treatments for SCI are necessary. In this review, we described the neuroprotective roles of several endocrine hormones in SCI; endocrine hormone administration reduces cell death and promotes functional repair after SCI. We also proposed novel therapies for SCI.

LncRNA Xist Contributes to Endogenous Neurological Repair After Chronic Compressive Spinal Cord Injury by Promoting Angiogenesis Through the miR-32-5p/Notch-1 Axis

Endogenous repair after chronic compressive spinal cord injury (CCSCI) is of great clinical interest. Ischemia-hypoxia-induced angiogenesis has been proposed to play an important role during this repair process. Emerging evidence indicates that long non-coding RNAs (lncRNAs) are involved in the pathophysiological processes of various diseases. Here, we identified a lncRNA (Xist; X-inactive specific transcript) with upregulated expression in cervical spine lesions during endogenous neurological repair in CCSCI rats. Therapeutically, the introduction of Xist to rats increased neurological function in vivo as assayed using the Basso, Beattie, and Bresnahan (BBB) score and inclined plane test (IPT). We found that the introduction of Xist enhanced endogenous neurological repair by promoting angiogenesis and microvessel density after CCSCI, while depletion of Xist inhibited angiogenesis and cell sprouting and migration. Mechanistically, Xist promoted angiogenesis by sponging miR-32-5p and modulating Notch-1 expression both in vitro and in vivo. These findings suggest a role of the Xist/miR-32-5p/Notch-1 axis in endogenous repair and provide a potential molecular target for the treatment of ischemia-related central nervous system (CNS) diseases.

Considerations for Studying Sex as a Biological Variable in Spinal Cord Injury

In response to NIH initiatives to investigate sex as a biological variable in preclinical animal studies, researchers have increased their focus on male and female differences in neurotrauma. Inclusion of both sexes when modeling neurotrauma is leading to the identification of novel areas for therapeutic and scientific exploitation. Here, we review the organizational and activational effects of sex hormones on recovery from injury and how these changes impact the long-term health of spinal cord injury (SCI) patients. When determining how sex affects SCI it remains imperative to expand outcomes beyond locomotor recovery and consider other complications plaguing the quality of life of patients with SCI. Interestingly, the SCI field predominately utilizes female rodents for basic science research which contrasts most other male-biased research fields. We discuss the unique caveats this creates to the translatability of preclinical research in the SCI field. We also review current clinical and preclinical data examining sex as biological variable in SCI. Further, we report how technical considerations such as housing, size, care management, and age, confound the interpretation of sex-specific effects in animal studies of SCI. We have uncovered novel findings regarding how age differentially affects mortality and injury-induced anemia in males and females after SCI, and further identified estrus cycle dysfunction in mice after injury. Emerging concepts underlying sexually dimorphic responses to therapy are also discussed. Through a combination of literature review and primary research observations we present a practical guide for considering and incorporating sex as biological variable in preclinical neurotrauma studies.

Is there any gender or age-related discrepancy in the waiting time for each step in the surgical management of acute traumatic cervical spinal cord injury?

Context/Objective: Prior studies indicate that patient's gender and age can influence treatment choices during spine disease management. This study examines whether individual's gender and age at injury onset influence the waiting time for each step in the surgical management of patients with acute traumatic cervical spinal cord injury (atcSCI). Design: Retrospective cohort study. Setting: Quaternary spine trauma center. Participants: This study included consecutive individuals with atcSCI admitted from August/2002 to October/2008 who were enrolled in the Surgical Trial in Acute Spinal Cord Injury Study (STASCIS). Interventions: Spinal cord decompression. Outcome Measures: Data on the periods of time for each step in the surgical management were analyzed to explore the potential effects of gender and age at injury onset. Results: There were 64 individuals with atcSCI (17 women, 47 men; age range: 18-78 years; mean age: 50.5 ± 2.1 years). Older age was associated with longer stay in the acute spine center, but this association was cofounded by major pre-existing medical co-morbidities. Age did not significantly affect the waiting time for each step in the surgical management of these individuals with atcSCI. Women underwent surgical assessment earlier than men. Gender did not influence other key steps in the surgical management. Conclusion: The study results suggest that older age at injury onset was associated with longer stay in the acute spine care center, and women had a shorter waiting time for surgical assessment than men. Nevertheless, no other age or gender bias was identified in the waiting times for the steps in the management of atcSCI.

Sex-related discrepancies in the epidemiology, injury characteristics and outcomes after acute spine trauma: A retrospective cohort study

Context/Objective: The potential effects of sex on injury severity and outcomes after acute spine trauma (AST) have been reported in pre-clinical and clinical studies, even though the data are conflicting. This study compared females and males regarding the epidemiology, injury characteristics, and clinical outcomes of AST. Design: Retrospective cohort study. Setting: Acute spine care quaternary center. Participants: All consecutive cases of AST admitted from January/1996 to December/2007 were included. Interventions: None. Outcome Measures: The potential effects of sex on the epidemiology, injury characteristics, and clinical outcomes of AST were studied. Results: There were 504 individuals with AST (161 females, 343 males; mean age of 49.44 ± 0.92 years). Sex was not associated with age or pre-existing co-morbidities as assessed using the Charlson Co-morbidity Index, however, females had a greater number of International Classifications of Diseases (ICD) codes at admission and higher Cumulative Illness Rating Scale (CIRS) than males. Over the 12-year period, the male-to-female ratio has not significantly changed. Although there were significant sex-related discrepancies regarding injury etiology, level and severity of AST, males and females had similar lengths of stay in the acute spine center, in-hospital survival post-AST, and need for mechanical ventilation and tracheostomy. Conclusion: This study suggests that females with AST present with a greater number of pre-existing co-morbidities, a higher frequency of thoraco-lumbar trauma, less severe neurological impairment and a greater proportion of MVA-related injuries. However, females and males have a similar length of stay in the acute spine center, and comparable in-hospital survival, need for mechanical ventilation, and tracheostomy after AST.

Functional and Histological Gender Comparison of Age-Matched Rats after Moderate Thoracic Contusive Spinal Cord Injury

Spinal cord injury (SCI) afflicts hundreds of thousands of Americans, and most SCI (∼80%) occurs in males. In experimental animal models, however, many studies used females. Funding agencies like the National Institutes of Health recommend that new proposed studies should include both genders due to variations in gender response to injuries, diseases, and treatments. However, cost and considerations for some animal models, such as SCI, affect investigators in adapting to this recommendation. Research has increased comparing gender effects in various disease and injury models, including SCI. However, most studies use weight-matched animals, which poses issues in comparing results and outcomes. The present study compared histologic and functional outcomes between age-matched male and female Sprague-Dawley rats in a moderate thoracic contusion SCI model. Cresyl violet and eosin staining showed no significant differences in lesion volume between genders after 9 weeks post-SCI (p > 0.05). Luxol fast blue-stained spared myelin was similar between genders, although slightly greater (∼6%) in spared myelin, compared with cord volume (p = 0.044). Glial reactivity and macrophage labeling in the lesion area was comparable between genders, as well. Basso, Beattie, Bresnahan (BBB) functional scores were not significantly different between genders, and Hargreaves thermal hyperalgesia and Gridwalk sensorimotor analyses also were similar between genders, compared with uninjured gender controls. Analysis of covariance showed weight did not influence functional recovery as assessed through BBB (p = 0.65) or Gridwalk assessment (p = 0.63) in this study. In conclusion, our findings suggest age-matched male and female rats recover similarly in a common clinically relevant SCI model.

Determining priorities in functional rehabilitation related to quality of life one-year following a traumatic spinal cord injury

Context/Objective: To determine the relationship between the different functional aspects (as determined by the Spinal Cord Independence Measure) and quality of life (QOL) following a traumatic spinal cord injury (TSCI), considering clinical confounding factors.Design: Retrospective review of a prospective cohortSetting: A single Level-1 trauma center specialized in SCI careParticipants: One hundred and forty-two individuals sustaining an acute traumatic SCIInterventions: Not applicableOutcome measures: The four QOL domains as assessed by the WHOQoL-bref questionnaire 6-12 months following a TSCI.Results: Mobility subscore was the only functional aspect significantly associated with all QOL domains (physical, psychological, social and environmental). Females present better chronic social and environmental QOL when compared to males. The level of injury may also influence environmental QOL.Conclusion: Mobility training (mobility in bed, mobility with or without technical aids, transfers and stair management) should be an important part of the rehabilitation process in order to optimize chronic QOL following a TSCI.

Combined effects of rat Schwann cells and 17β-estradiol in a spinal cord injury model

Spinal cord injury (SCI) is a devastating traumatic event which burdens the affected individuals and the health system. Schwann cell (SC) transplantation is a promising repair strategy after SCI. However, a large number of SCs do not survive following transplantation. Previous studies demonstrated that 17β-estradiol (E2) protects different cell types and reduces tissue damage in SCI experimental animal model. In the current study, we evaluated the protective potential of E2 on SCs in vitro and investigated whether the combination of hormonal and SC therapeutic strategy has a better effect on the outcome after SCI. Primary SC cultures were incubated with E2 for 72 h. In a subsequent experiment, thoracic contusion SCI was induced in male rats followed by sustained administration of E2 or vehicle. Eight days after SCI, DiI-labeled SCs were transplanted into the injury epicenter in vehicle and E2-treated animals. The combinatory regimen decreased neurological and behavioral deficits and protected neurons and oligodendrocytes in comparison to vehicle rats. Moreover, E2 and SC significantly decreased the number of Iba-1+ (microglia) and GFAP⁺ cells (astrocyte) in the SCI group. In addition, we found a significant reduction of mitochondrial fission-markers (Fis1) and an increase of fusion-markers (Mfn1 and Mfn2) in the injured spinal cord after E2 and SC treatment. These data demonstrated that E2 protects SCs against hypoxia-induced SCI and improves the survival of transplanted SCs.

Intramedullary Lesion Length on Postoperative Magnetic Resonance Imaging is a Strong Predictor of ASIA Impairment Scale Grade Conversion Following Decompressive Surgery in Cervical Spinal Cord Injury

BACKGROUND

Evidence indicates that, over time, patients with spinal cord injury (SCI) improve neurologically in various degrees. We sought to further investigate indicators of grade conversion in cervical SCI.

OBJECTIVE

To detect predictors of ASIA impairment scale (AIS) grade conversion in SCI following surgical decompression.

METHODS

In a retrospective study, demographics, clinical, imaging, and surgical data from 100 consecutive patients were assessed for predictors of AIS grade conversion.

RESULTS

American Spinal Injury Association motor score was 17.1. AIS grade was A in 52%, B in 29%, and C in 19% of patients. Surgical decompression took place on an average of 17.6 h following trauma (≤12 h in 51 and >12 h in 49). Complete decompression was verified by magnetic resonance imaging (MRI) in 73 patients. Intramedullary lesion length (IMLL) on postoperative MRI measured 72.8 mm, and hemorrhage at the injury epicenter was noted in 71 patients. Grade conversion took place in 26.9% of AIS grade A patients, 65.5% of AIS grade B, and 78.9% of AIS grade C. AIS grade conversion had statistical relationship with injury severity score, admission AIS grade, extent of decompression, presence of intramedullary hemorrhage, American Spinal Injury Association motor score, and IMLL. A stepwise multiple logistic regression analysis indicated IMLL was the sole and strongest indicator of AIS grade conversion (odds ratio 0.950, 95% CI 0.931-0.969). For 1- and 10-mm increases in IMLL, the model indicates 4% and 40% decreases, respectively, in the odds of AIS grade conversion.

CONCLUSION

Compared with other surrogates, IMLL remained as the only predictor of AIS grade conversion.

miR-155 Deletion in Mice Overcomes Neuron-Intrinsic and Neuron-Extrinsic Barriers to Spinal Cord Repair

Axon regeneration after spinal cord injury (SCI) fails due to neuron-intrinsic mechanisms and extracellular barriers including inflammation. microRNA (miR)-155-5p is a small, noncoding RNA that negatively regulates mRNA translation. In macrophages, miR-155-5p is induced by inflammatory stimuli and elicits a response that could be toxic after SCI. miR-155 may also independently alter expression of genes that regulate axon growth in neurons. Here, we hypothesized that miR-155 deletion would simultaneously improve axon growth and reduce neuroinflammation after SCI by acting on both neurons and macrophages. New data show that miR-155 deletion attenuates inflammatory signaling in macrophages, reduces macrophage-mediated neuron toxicity, and increases macrophage-elicited axon growth by ∼40% relative to control conditions. In addition, miR-155 deletion increases spontaneous axon growth from neurons; adult miR-155 KO dorsal root ganglion (DRG) neurons extend 44% longer neurites than WT neurons. In vivo, miR-155 deletion augments conditioning lesion-induced intraneuronal expression of SPRR1A, a regeneration-associated gene; ∼50% more injured KO DRG neurons expressed SPRR1A versus WT neurons. After dorsal column SCI, miR-155 KO mouse spinal cord has reduced neuroinflammation and increased peripheral conditioning-lesion-enhanced axon regeneration beyond the epicenter. Finally, in a model of spinal contusion injury, miR-155 deletion improves locomotor function at postinjury times corresponding with the arrival and maximal appearance of activated intraspinal macrophages. In miR-155 KO mice, improved locomotor function is associated with smaller contusion lesions and decreased accumulation of inflammatory macrophages. Collectively, these data indicate that miR-155 is a novel therapeutic target capable of simultaneously overcoming neuron-intrinsic and neuron-extrinsic barriers to repair after SCI.

SIGNIFICANCE STATEMENT

Axon regeneration after spinal cord injury (SCI) fails due to neuron-intrinsic mechanisms and extracellular barriers, including inflammation. Here, new data show that deleting microRNA-155 (miR-155) affects both mechanisms and improves repair and functional recovery after SCI. Macrophages lacking miR-155 have altered inflammatory capacity, which enhances neuron survival and axon growth of cocultured neurons. In addition, independent of macrophages, adult miR-155 KO neurons show enhanced spontaneous axon growth. Using either spinal cord dorsal column crush or contusion injury models, miR-155 deletion improves indices of repair and recovery. Therefore, miR-155 has a dual role in regulating spinal cord repair and may be a novel therapeutic target for SCI and other CNS pathologies.

Previously Identified Common Post-Injury Adverse Events in Traumatic Spinal Cord Injury-Validation of Existing Literature and Relation to Selected Potentially Modifiable Comorbidities: A Prospective Canadian Cohort Study

Adverse events (AEs) are common during care in patients with traumatic spinal cord injury (tSCI). Increased risk of AEs is linked to patient factors including pre-existing comorbidities. Our aim was to examine the relationships between patient factors and common post-injury AEs, and identify potentially modifiable comorbidities. Adults with tSCI admitted to a Level I acute specialized spine center between 2006 and 2014 who were enrolled in the Rick Hansen SCI Registry (RHSCIR) and had AE data collected using the Spine Adverse Events Severity system were included. Patient demographic, neurological injury, and comorbidities data were obtained from RHSCIR. Potentially modifiable comorbidities were grouped into health-related conditions, substance use/withdrawal, and psychiatric conditions. Negative binomial regression and multiple logistic regression were used to model the impact of patient factors on the number of AEs experienced and the occurrence of the five previously identified common AEs, respectively. Of the 444 patients included in the study, 24.8% reported a health-related condition, 15.3% had a substance use/withdrawal condition, 8% reported having a psychiatric condition; and 79.3% experienced one or more AEs. Older age (p = 0.004) and more severe injuries (p < 0.001) were nonmodifiable independent variables significantly associated with increased AEs. The AEs experienced by patients were urinary tract infections (42.8%), pneumonia (39.2%), neuropathic pain (31.5%), delirium (18.2%), and pressure ulcers (11.0%). Risk of delirium increased in those with substance use/withdrawal; and pneumonia risk increased with psychiatric comorbidities. Opportunity exists to develop clinical algorithms that include these types of risk factors to reduce the incidence and impact of AEs.

Comparison of Gender Differences in Intracerebral Hemorrhage in a Multi-Ethnic Asian Population

BACKGROUND

Intracerebral hemorrhage (ICH) accounts for 10-15% of all first time strokes and with incidence twice as high in the Asian compared to Western population. This study aims to investigate gender differences in ICH patient outcomes in a multi-ethnic Asian population.

METHOD

Data for 1,192 patients admitted for ICH were collected over a four-year period. Multivariate logistic regression was used to identify independent predictors and odds ratios were computed for 30-day mortality and Glasgow Outcome Scale (GOS) comparing males and females.

RESULT

Males suffered ICH at a younger age than females (62.2 ± 13.2 years vs. 66.3 ± 15.3 years; P<0.001). The occurrence of ICH was higher among males than females at all ages until 80 years old, beyond which the trend was reversed. Females exhibited increased severity on admission as measured by Glasgow Coma Scale compared to males (10.9 ± 4.03 vs. 11.4 ± 4.04; P = 0.030). No difference was found in 30-day mortality between females and males (F: 30.5% [155/508] vs. M: 27.0% [186/688]), with unadjusted and adjusted odds ratio (F/M) of 1.19 (P = 0.188) and 1.21 (P = 0.300). At discharge, there was a non-statistically significant but potentially clinically relevant morbidity difference between the genders as measured by GOS (dichotomized GOS of 4-5: F: 23.7% [119/503] vs. M: 28.7% [194/677]), with unadjusted and adjusted odds ratio (F/M) of 0.77 (P = 0.055) and 0.87 (P = 0.434).

CONCLUSION

In our multi-ethnic Asian population, males developed ICH at a younger age and were more susceptible to ICH than women at all ages other than the beyond 80-year old age group. In contrast to the Western population, neurological status of female ICH patients at admission was poorer and their 30-day mortality was not reduced. Although the study was not powered to detect significance, female showed a trend toward worse 30-day morbidity at discharge.

Mortality and longevity after a spinal cord injury: systematic review and meta-analysis

BACKGROUND/AIMS

Mortality and longevity studies of spinal cord injury (SCI) are essential for informing healthcare systems and policies. This review evaluates the current evidence among people with SCIs worldwide in relation to the WHO region and country income level; demographic and lesion characteristics; and in comparison with the general population.

METHODS

A systematic review of relevant databases for original studies. Pooled estimates were derived using random effects meta-analysis, restricted to traumatic SCI.

RESULTS

Seventy-four studies were included. In-hospital mortality varied, with pooled estimates of 24.1% (95% confidence interval (CI) 14.1-38.0), 7.6% (95% CI 6.3-9.0), 7.0% (95% CI 1.5-27.4), and 2.1% (95% CI 0.9-5.0) in the WHO regions of Africa, the Americas, Europe and Western Pacific. The combined estimate for low- and middle-income countries was nearly three times higher than for high-income countries. Pooled estimates of first-year survival were 86.5% (95% CI 75.3-93.1), 95.6% (95% CI 81.0-99.1), and 94.0% (95% CI 93.3-94.6) in the Americas, Europe and Western Pacific. Pooled estimates of standardized mortality ratios in tetraplegics were 2.53 (2.00-3.21) and 2.07 (1.47-2.92) in paraplegics.

CONCLUSION

This study found substantial variation in mortality and longevity within the SCI population, compared to the general population, and between WHO regions and country income level. Improved standardization and quality of reporting is needed to improve inferences regarding the extent to which mortality outcomes following an SCI are related to healthcare systems, services and policies.

Female Rats Demonstrate Improved Locomotor Recovery and Greater Preservation of White and Gray Matter after Traumatic Spinal Cord Injury Compared to Males

The possibility of a gender-related difference in recovery after spinal cord injury (SCI) remains a controversial subject. Current empirical animal research lacks sizable test groups to definitively determine whether significant differences exist. Evaluating locomotor recovery variances between sexes following a precise, clinically relevant spinal cord contusion model can provide valuable insight into a possible gender-related advantage in outcome post-SCI. In the current study, we hypothesized that by employing larger sample sizes in a reproducible contusive SCI paradigm, subtle distinctions in locomotor recovery between sexes, if they exist, would be elucidated through a broad range of behavioral tests. During 13 weeks of functional assessment after a thoracic (T8) contusive SCI in rat, significant differences owing to gender existed for the Basso, Beattie, and Bresnahan score and CatWalk hindlimb swing, support four, and single stance analyses. Significant differences in locomotor performance were noticeable as early as 4 weeks post-SCI. Stereological tissue-volume analysis determined that females, more so than males, also exhibited greater volumes of preserved gray and white matter within the injured cord segment as well as more spared ventral white matter area at the center of the lesion. The stereological tissue analysis differences favoring females directly correlated with the female rats' greater functional improvement observed at endpoint.

G-protein-coupled receptor 30-mediated antiapoptotic effect of estrogen on spinal motor neurons following injury and its underlying mechanisms

Spinal cord injury (SCI) may result in severe dysfunction of motor neurons. G-protein-coupled receptor 30 (GPR30) expression in the motor neurons of the ventral horn of the spinal cord mediates neuroprotection through estrogen signaling. The present study explored the antiapoptotic effect of estrogen, mediated by GPR30 following SCI, and the mechanisms underlying this effect. Spinal motor neurons from rats were cultured in vitro in order to establish cell models of oxygen and glucose deprivation (OGD). The effects of estrogen, the estrogen agonist, G1, and the estrogen inhibitor, G15, on motor neurons were observed using MTT assays. The effects of E2, G1 and G15 on spinal motor neuron apoptosis following OGD, were detected using flow cytometry. The role of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) inhibitor, LY294002, was also determined using flow cytometry. Rat SCI models were established. E2, G1 and E2+LY294002 were administered in vivo. Motor function was scored at 3, 7, 14, 21 and 28 d following injury, using Basso-Beattie-Bresnahan (BBB) standards. Cell activity in the estrogen and G1 groups was higher than that in the solvent group, whereas cell activity in the E2+G15 group was lower than that in the E2 group (P<0.05). Following OGD, the proportion of apoptotic cells significantly increased (P<0.05). The proportion in the estrogen group was significantly lower than that in the solvent group, whereas the proportion of apoptotic cells in the E2+G15 and E2+LY294002 groups was higher than that in the E2 group (P<0.05). Treatment with E2 and G1 led to upregulation of P-Akt expression in normal cells and post-OGD cells. The BBB scores of rats in the E2 and G1 groups were higher than those in the placebo group (P<0.05). The BBB scores of the E2+LY294002 group were lower than those of the E2 group (P<0.05). Estrogen thus appears to exert a protective effect on spinal motor neurons following OGD, via GPR30. The PI3K/Akt pathway may be one of those involved in the estrogen-related antiapoptotic effects mediated by GPR30.

Estrogen influences on neuromuscular function in postmenopausal women

Exposure to ovarian sex steroids during different life phases has long-term effects on women's health and wellbeing. Menopause is characterized by rapid decline in ovarian sex steroids already during mid-life, between the ages of 46 and 52. Due to the menopause-related hormonal changes, women in most western countries live more than one-third of their lives in postmenopausal status. The role of ovarian steroids on neuromuscular function in middle-aged and older women has been investigated since the 1980s with increasing volume of research during the last decades. This review considers how different components of the neuromuscular system may be influenced by estrogens and so affects neuromuscular function in postmenopausal women. The main focus is on muscle strength and power, which are closely associated with mobility and functional capacity among older populations. In the end of the review, we summarize recent findings on the underlying biological mechanisms in skeletal muscle that could explain the association between hormone replacement therapy and neuromuscular function among postmenopausal women.

The influence of time from injury to surgery on motor recovery and length of hospital stay in acute traumatic spinal cord injury: an observational Canadian cohort study

To determine the influence of time from injury to surgery on neurological recovery and length of stay (LOS) in an observational cohort of individuals with traumatic spinal cord injury (tSCI), we analyzed the baseline and follow-up motor scores of participants in the Rick Hansen Spinal Cord Injury Registry to specifically assess the effect of an early (less than 24 h from injury) surgical procedure on motor recovery and on LOS. One thousand four hundred and ten patients who sustained acute tSCIs with baseline American Spinal Injury Association Impairment Scale (AIS) grades A, B, C, or D and were treated surgically were analyzed to determine the effect of the timing of surgery (24, 48, or 72 h from injury) on motor recovery and LOS. Depending on the distribution of data, we used different types of generalized linear models, including multiple linear regression, gamma regression, and negative binomial regression. Persons with incomplete AIS B, C, and D injuries from C2 to L2 demonstrated motor recovery improvement of an additional 6.3 motor points (SE=2.8 p<0.03) when they underwent surgical treatment within 24 h from the time of injury, compared with those who had surgery later than 24 h post-injury. This beneficial effect of early surgery on motor recovery was not seen in the patients with AIS A complete SCI. AIS A and B patients who received early surgery experienced shorter hospital LOS. While the issues of when to perform surgery and what specific operation to perform remain controversial, this work provides evidence that for an incomplete acute tSCI in the cervical, thoracic, or thoracolumbar spine, surgery performed within 24 h from injury improves motor neurological recovery. Early surgery also reduces LOS.

Sex steroids and neuroprotection in spinal cord injury: a review of preclinical investigations

Spinal cord injury (SCI) is a debilitating condition that affects motor, sensory and autonomic functions. Subsequent to the first mechanical trauma, secondary events, which include inflammation and glial activation, exacerbate tissue damage and worsen functional deficits. Although these secondary injury mechanisms are amenable to therapeutic interventions, the efficacy of current approaches is inadequate. Further investigations are necessary to implement new therapies that can protect neural cells and attenuate some of the detrimental effects of inflammation while promoting regeneration. Studies on different animal models of SCI indicated that sex steroids, especially 17β-estradiol and progesterone, exert neuroprotective, anti-apoptotic and anti-inflammatory effects, ameliorate tissue sparing and improve functional deficits in SCI. As sex steroid receptors are expressed in a variety of cells including neurons, glia and immune system-related cells which infiltrate the injury epicenter, sex steroids could impact multiple processes simultaneously and in doing so, influence the outcomes of SCI. However, the translation of these pre-clinical findings into the clinical setting presents challenges such as the narrow therapeutic time window of sex steroid administration, the diversity of treatment regimens that have been employed in animal studies and the lack of sufficient information regarding the persistence of the effects in chronic SCI. The current review will summarize some of the major findings in this field and will discuss the challenges associated with the implementation of sex steroids as a promising treatment in human SCI.

Cardiometabolic risk profiles in pre- versus postmenopausal women with spinal cord injury:: preliminary findings

OBJECTIVE

To compare the cardiometabolic risk (CMR) profile of premenopausal and postmenopausal women with spinal cord injury (SCI).

METHOD

Post hoc analysis of a multicenter cross-sectional study assessing CMR. Seventeen women with ASIA Impairment Scale (AIS) A or B SCI between C5 and T12 were stratified into 2 groups according to menopausal status (11 premenopausal vs 6 postmenopausal women). Data collected included demographic, social, medical, menopausal, hormone use, and menstrual histories. Assessments included physical, anthropometric, and blood pressure measures; fasting serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and hemoglobin A1C (Hb1Ac); calculated low-density lipoprotein (LDL-C); and an oral glucose tolerance test.

RESULTS

The premenopausal group had a mean age of 32.4 years compared with 56.0 years in the postmenopausal group. Similar group findings included body mass index (BMI) (22.4 vs 22.2), HDL-C (52.5 vs 53 mg/dL), HbA1c (4.9 vs 5.1%), fasting blood glucose (FBG) (79.3 vs 84.8 mg/dL), and systolic blood pressure (SBP) (104.6 vs 111.8 mm Hg). TG, TC and LDL-C were significantly higher in postmenopausal group (55.7 vs 101.8 mg/dL, P = .01; 158.3 vs 191.6 mg/dL, P = .04; 94.7 vs 118.2 mg/dL, P = .04).

CONCLUSIONS

The findings from this study suggest that postmenopausal women with SCI have CMR trends similar to those observed in nondisabled women, characterized by increases in TG, TC, and LDL-C despite favorable BMIs and glycemic indices. Even though the present study includes significant limitations, future evidence may also suggest that heightened surveillance and guideline-driven interventions are indicated for perimenopausal and postmenopausal women with SCI.

Effect of gender on recovery after spinal cord injury

Spinal cord injury (SCI) is a debilitating condition that affects thousands of new individuals each year, the majority of which are males. Males with SCI tend to be injured at an earlier age, mostly during sports or motor vehicle accidents, whereas females tend be injured later in life, particularly in the age group 65 and older. In both experimental and clinical studies, the question as to whether gender affects outcome has been addressed in a variety of patient groups and animal models. Results from experimental paradigms have suggested that a gender bias in outcome exists that favors females and appears to involve the advantageous or disadvantageous effects of the gonadal sex hormones estrogen and progesterone or testosterone, respectively. However, other studies have shown an absence of gender differences in outcome in specific SCI models and work has also questioned the involvement of female sex hormones in the observed outcome improvements in females. Similar controversy exists clinically, in studies that have examined gender disparities in outcome after SCI. The current review examines the experimental and clinical evidence for a gender bias in outcome following SCI and discusses issues that have made it difficult to conclusively answer this question.

Incidence and severity of acute complications after spinal cord injury

Object

The aim of this multicenter, prospective study was to determine the spectrum, incidence, and severity of complications during the initial hospitalization of patients with spinal cord injury.

Methods

The study was conducted at 9 university-affiliated hospitals that comprise the clinical centers of the North American Clinical Trials Network (NACTN) for Treatment of Spinal Cord Injury. The study population comprised 315 patients admitted to NACTN clinical centers between June 25, 2005, and November 2, 2010, who had American Spinal Injury Association (ASIA) Impairment Scale grades of A–D and were 18 years of age or older. Patients were managed according to a standardized protocol.

Results

The study population was 79% male with a median age of 44 years. The leading causes of injury were falls (37%) and motor vehicle accidents (28%). The distribution of initial ASIA grades were A (40%), B (16%), C (15%), and D (29%). Fifty-eight percent of patients sustained 1 or more severe, moderate, or mild complications. Complications were associated with more severe ASIA grade: 84% of patients with Grade A and 25% of patients with Grade D had at least 1 complication. Seventy-eight percent of complications occurred within 14 days of injury. The most frequent types of severe and moderate complications were respiratory failure, pneumonia, pleural effusion, anemia, cardiac dysrhythmia, and severe bradycardia. The mortality rate was 3.5% and was associated with increased age and preexisting morbidity.

Conclusions

Knowledge of the type, frequency, time of occurrence, and severity of specific complications that occur after spinal cord injury can aid in their early detection, treatment, and prevention. The data are of importance in evaluating and selecting therapy for clinical trials.

Current trends in venous thromboembolism among persons hospitalized with acute traumatic spinal cord injury: does early access to rehabilitation matter?

OBJECTIVE

To determine the incidence of venous thromboembolism (VTE) among patients with traumatic spinal cord injury (TSCI) in acute care settings that is attributable to extended length of stay (LOS), insurance status, and access to rehabilitation.

DESIGN

Population-based, retrospective cohort study.

SETTING

Levels I through III and undesignated trauma centers.

PARTICIPANTS

Patients with acute TSCI (N=3389) discharged from all acute care hospitals in South Carolina from 1998 through 2009, and a representative sample of patients with TSCI (n=186) interviewed 1 year later.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

VTE while in acute care.

RESULTS

Annual incidence of TSCI is 67.2 per million in the state of South Carolina, while the cumulative incidence of VTE is 4.1%. Patients with TSCI who developed VTE were nearly 4 times more likely (odds ratio [OR], 3.98; 95% confidence interval [CI], 2.57-6.17) to have been those who stayed 12 days or longer in acute care after adjusting for covariates. The adjusted mean LOS in acute care was 32.0 days (95% CI, 27.7-37.2) for patients with TSCI who had indigent insurance versus 11.3 days (95% CI, 4.9-17.6) for Medicare, and 18.5 days (95% CI, 14.5-22.5) for commercial insurance after adjusting for VTE, disposition, and year of discharge. Only 20% of the persons under indigent care received rehabilitation from accredited rehabilitation facilities in contrast to 60% under commercial insurance.

CONCLUSIONS

Fewer patients with TSCI under indigent care received postacute rehabilitation compared with Medicare or commercial insurance. Insurance status remains a major barrier to timely transfer to rehabilitation, leading to protracted LOS in acute care with increased risk of VTE.

Prehospital transport of patients with spinal cord injury in Nigeria

BACKGROUND

A well-organized and efficient prehospital transport is associated with improved outcome in trauma patients. In Nigeria, there is paucity of information on prehospital transport of patients with spinal cord injury (SCI) and its relation to mortality.

OBJECTIVE

To determine if prehospital transportation is a predictor of mortality in patients with SCI in Nigeria.

DESIGN

Prospective cohort study

METHODS

Prehospital transport related conditions, injury arrival intervals and persons that brought patients with SCI to the casualty were noted. Data analyzed using descriptive statistics, the chi-square test and multiple logistic regressions.

MAIN OUTCOME MEASURES

Mortality within 6 weeks on admission

RESULTS

168 patients with SCI presented in the casualty during this review period. Majority (67.9%) presented after 24 hrs of the injury. Majority (58.3%) were conveyed into the casualty by their relatives. Salon car (54.2%) was the most common mode of transportation where majority (55.4%) laid on their back during the transfer. Majority (75%) of the patients had multiple hospital presentation before reporting in our casualty. The mortality observed was 16.7%. Multivariate analysis after adjusting for age, gender, and means of transportation revealed that age (OR= 63.41, 95% CI= 9.24-43.53), crouched position during transfer (OR= 23.52, 95% CI= 7.26-74.53), presentation after 24 hrs (OR=5.48, 95% CI=3.20-16.42) and multiple hospital presentation (OR= 7.94, 95% CI= 1.89-33.43) were associated with mortality within 6 weeks of admission.

CONCLUSION

A well-organized and efficient prehospital transport would reduce mortality in spinal cord injured patients. Public enlightenment campaign on factors that could reduce road traffic injury would help reduce mortality.

Challenges, concerns and common problems: physiological consequences of spinal cord injury and microgravity

INTRODUCTION

Similarities between the clinical presentation of individuals living with spinal cord injury (SCI) and astronauts are remarkable, and may be of great interest to clinicians and scientists alike.

OBJECTIVES

The primary purpose of this review is to outline the manner in which cardiovascular, musculoskeletal, renal, immune and sensory motor systems are affected by microgravity and SCI.

METHODS

A comprehensive review of the literature was conducted (using PubMed) to evaluate the hallmark symptoms seen after spaceflight and SCI. This literature was then examined critically to determine symptoms common to both populations.

RESULTS

Both SCI and prolonged microgravity exposure are associated with marked deteriorations in various physiological functions. Atrophy in muscle and bone, cardiovascular disturbances, and alterations in renal, immune and sensory motor systems are conditions commonly observed not only in individuals with SCI, but also in those who experience prolonged gravity unloading.

CONCLUSION

The preponderance of data indicates that similar physiological changes occur in both SCI and prolonged space flight. These findings have important implications for future research in SCI and prolonged space flight.

Comparison of immunopathology and locomotor recovery in C57BL/6, BUB/BnJ, and NOD-SCID mice after contusion spinal cord injury

Studies of cell transplantation therapeutics in animal models of traumatic spinal cord injury (SCI) are often hampered by partial or complete rejection of the graft by the host. Pharmacological immunosuppression is rarely sufficient to prevent rejection. Further, the immunological niche created by both the host immune response and immunosuppressant drugs could hypothetically influence the proliferation, differentiation, and fate of transplanted progenitor/stem cells. To avoid these confounds, we have previously used the constitutively immunodeficient non-obese diabetic severe combined immunodeficient (NOD-SCID) mouse as a model for transplantation studies following SCI. In the current study, we compare behavioral and histological recovery in NOD-SCID, C57BL/6, and BUB/BnJ mice of both sexes to better facilitate interpretation of data from studies using NOD-SCID mice. Of the strains examined, NOD-SCID mice exhibited the greatest locomotor recovery in the open field; no sex differences were detected in locomotor recovery in any of the strains. Stereologic estimation of the number of infiltrated neutrophils showed more cells in C57BL/6 mice than NOD-SCID mice, with BUB/BnJ mice having an intermediate number. The volume of macrophages/microglia did not differ between strains or sexes, though more rostral-caudal spreading was observed in C57BL/6 and BUB/BnJ than NOD-SCID mice. No significant differences were detected in lesion volume. Taken together these findings demonstrate that relative to other strains, NOD-SCID mice have both similar primary lesion volume and cellular inflammatory parameters after SCI, and support the applicability of the model for neurotransplantation studies.

Attitudes toward the elderly with CNS trauma: a cross-sectional study of neuroscientists, clinicians, and allied-health professionals

Despite the potential impact of ageist attitudes on outcomes of central nervous system (CNS)-injured patients, little has been reported on this issue. Given this, we sought to conduct a questionnaire-based survey to assess the attitudes toward the elderly among basic and clinical neuroscientists, clinicians, and allied-health professionals whose research or medical practice is focused on neurotrauma. We also reviewed all abstracts presented in the National Neurotrauma Symposia from 1984 to 2007 and identified previous studies on the potential effects of age/aging on outcomes. The Kogan's Old People (KOP) scale was used to assess attitudes toward elderly individuals among all members of the National Neurotrauma Society (NNS). Of the 504 registered members, 137 subjects completed the survey that was re-mailed for non-respondents 4 weeks apart. There were no significant differences between respondents of the first and second mailings regarding their demographic and professional profiles or regarding their responses. These results support the validity of our findings in spite of the relatively low mail survey response rate (27.2%). Female gender was significantly associated with more positive attitudes toward old people compared to males. Clinicians showed significantly fewer negative attitudes toward old people in comparison with basic and clinical neuroscientists. Of the 4,194 abstracts reviewed, we identified only 44 studies (1.05%) that were explicitly focused on the effects of aging/old age on neurotrauma. In conclusion, our questionnaire-based survey, which appears to be representative of the population of interest, recognized significant differences in the attitudes toward old people among various professional groups and between male and female professionals. These findings may reflect a lack of knowledge and misconceptions regarding the impact of aging and old age on outcomes after CNS trauma. Further research on the impact of aging on outcomes after neurotrauma is required. Moreover, knowledge translation and mobilization appears required to positively influence attitudes among neuroscience research and clinical professionals regarding the issues of neurotrauma and the elderly.

Muscle after spinal cord injury

The morphological and contractile changes of muscles below the level of the lesion after spinal cord injury (SCI) are dramatic. In humans with SCI, a fiber-type transformation away from type I begins 4-7 months post-SCI and reaches a new steady state with predominantly fast glycolytic IIX fibers years after the injury. There is a progressive drop in the proportion of slow myosin heavy chain (MHC) isoform fibers and a rise in the proportion of fibers that coexpress both the fast and slow MHC isoforms. The oxidative enzymatic activity starts to decline after the first few months post-SCI. Muscles from individuals with chronic SCI show less resistance to fatigue, and the speed-related contractile properties change, becoming faster. These findings are also present in animals. Future studies should longitudinally examine changes in muscles from early SCI until steady state is reached in order to determine optimal training protocols for maintaining skeletal muscle after paralysis.

Fracture characteristics predict patient mortality after blunt force cervical trauma

Fractures of the cervical spine after blunt cervical trauma are associated with high rates of patient mortality. The purpose of this study was to investigate patient and fracture characteristics that predict mortality. This is a retrospective, case cohort study of all adult patients admitted to our institution between January 1998 and June 2008 with cervical fracture after blunt cervical trauma (N=218). All patient records were reviewed. The patient and fracture characteristics and outcome data were stored. Age (P=0.002), involvement of the fourth cervical vertebra (P=0.002), lamina fracture (P=0.001), and a facet fracture (P=0.006) were identified as independent significant risk factors for mortality. In conclusion, mortality is highly affected by patient age, but fracture location and fracture pattern are also predictive of poor patient outcome. Fracture patterns may increase the risk of spinal cord injury at a level that can affect but not eliminate neural control of the diaphragm, which have the worst prognosis for patient mortality.

Traumatic spinal cord injury mortality, 1981-1998

BACKGROUND

We aim to assess the long-term trend of and identify risk factors for traumatic spinal cord injury (TSCI) mortality from 1981 through 1998 in the state of South Carolina (SC).

METHODS

We analyzed data from the TSCI surveillance system in SC. Poisson regression analyses were used to examine trends in TSCI mortality rates across subpopulations of interest. Multiple logistic regression was used to identify risk factors for TSCI mortality.

RESULTS

The rate of TSCI mortality was 27.4 per million population between 1981 and 1998. A significant 3% annual decrease in the TSCI mortality rate was found from 1981 through 1998. Specifically, TSCI mortality rates declined the most per year in motor vehicle crashes, males, and whites. Adjusted for covariates, individuals of older ages, black race, with a cervical TSCI, and with a more severe injury, as defined by both Frankel grade and Abbreviated Injury Scale, were associated with higher odds of in-hospital mortality. Females had lower odds of in-hospital mortality than males.

CONCLUSION

Although mortality rate is decreasing, TSCI remains a significant public health problem, with SC having higher rates of TSCI mortality than the United States. The association between gender and in-hospital mortality needs further exploration.

Risk factors predicting mortality after blunt traumatic cervical fracture

OBJECTIVE

Risk factors for mortality after blunt cervical trauma have received little attention within the literature. Therefore, we performed a study, to determine which factors are associated with mortality in patients with blunt cervical trauma.

STUDY DESIGN

A retrospective study of 88 trauma patients, with cervical fractures, who were admitted to the emergency department of the St. Elisabeth hospital, Tilburg, The Netherlands.

SUMMARY OF BACKGROUND DATA

A retrospective cohort study was performed within the trauma department of the St. Elisabeth Hospital, in Tilburg, The Netherlands. From January 2000 to December 2005, all patients with cervical fractures after blunt trauma were included (N=88). All patient records were reviewed. Patient and trauma characteristics were registered within a standardised electronic database. Our follow-up period was 1 year.

RESULTS

In total, 12 (13.6%) patients died after a traumatic cervical fracture. Age (p=0.005), gender (p=0.005), involvement of the third cervical vertebrae (p=0.003), involvement of three cervical vertebrae (p=0.010) and involvement of the spinous process (p=0.032) were associated with mortality. The multivariate analysis showed that age and the involvement of the third cervical vertebrae (both p=0.016) are both independently associated with mortality.

CONCLUSION

Age and involvement of the third cervical vertebrae were both independent predictors of mortality. Age has been previously described as a risk factor for adverse prognosis in different diseases and trauma's. However, involvement of the third cervical vertebrae has not yet been described as a significant risk factor. Before implementation within trauma support further research is needed to evaluate the role of the third cervical vertebra regarding adverse prognosis and mortality in trauma patients.

Traumatic spine injuries in the geriatric population

In this paper the authors review spine trauma and spinal cord injury (SCI) in the geriatric population. The information in this study was compiled through a literature review of clinical presentation and management of SCI in the elderly population. This was done to define, identify, and specify treatment algorithms and management strategies in this unique patient population.