Changing trends in traumatic spinal cord injury in an aging society: Epidemiology of 1152 cases over 15 years from a single center in Japan

Traumatic spinal cord injury (TSCI) causes an insult to the central nervous system, often resulting in devastating temporary or permanent neurological impairment and disability, which places a substantial financial burden on the health-care system. This study aimed to clarify the up-to-date epidemiology and demographics of patients with TSCI treated at the largest SCI center in Japan. Data on all patients admitted to the Spinal Injuries Center with TSCI between May 2005 and December 2021 were prospectively collected using a customized, locally designed SCI database named the Japan Single Center Study for Spinal Cord Injury Database (JSSCI-DB). A total of 1152 patients were identified from the database. The study period was divided into the four- or five-year periods of 2005-2009, 2010-2013, 2014-2017, and 2018-2021 to facilitate the observation of general trends over time. Our results revealed a statistically significant increasing trend in age at injury. Since 2014, the average age of injury has increased to exceed 60 years. The most frequent spinal level affected by the injury was high cervical (C1-C4: 45.8%), followed by low cervical (C5-C8: 26.4%). Incomplete tetraplegia was the most common cause or etiology category of TSCI, accounting for 48.4% of cases. As the number of injuries among the elderly has increased, the injury mechanisms have shifted from high-fall trauma and traffic accidents to falls on level surfaces and downstairs. Incomplete tetraplegia in the elderly due to upper cervical TSCI has also increased over time. The percentage of injured patients with an etiology linked to alcohol use ranged from 13.2% (2005-2008) to 19% (2014-2017). Given that Japan has one of the highest aging populations in the world, epidemiological studies in this country will be very helpful in determining health insurance and medical costs and deciding strategies for the prevention and treatment of TSCI in future aging populations worldwide.

Verification of the Accuracy of Cervical Spinal Cord Injury Prognosis Prediction Using Clinical Data-Based Artificial Neural Networks

BACKGROUND

In patients with cervical spinal cord injury (SCI), we need to make accurate prognostic predictions in the acute phase for more effective rehabilitation. We hypothesized that a multivariate prognosis would be useful for patients with cervical SCI.

METHODS

We made two predictive models using Multiple Linear Regression (MLR) and Artificial Neural Networks (ANNs). We adopted MLR as a conventional predictive model. Both models were created using the same 20 clinical parameters of the acute phase data at the time of admission. The prediction results were classified by the ASIA Impairment Scale. The training data consisted of 60 cases, and prognosis prediction was performed for 20 future cases (test cohort). All patients were treated in the Spinal Injuries Center (SIC) in Fukuoka, Japan.

RESULTS

A total of 16 out of 20 cases were predictable. The correct answer rate of MLR was 31.3%, while the rate of ANNs was 75.0% (number of correct answers: 12).

CONCLUSION

We were able to predict the prognosis of patients with cervical SCI from acute clinical data using ANNs. Performing effective rehabilitation based on this prediction will improve the patient's quality of life after discharge. Although there is room for improvement, ANNs are useful as a prognostic tool for patients with cervical SCI.

Heat-stable spores of carotenoid-producing Bacillus marisflavi and non-pigmented Bacillus subtilis cooperatively promote growth, quality, and gut microbiota of white-leg shrimp

We evaluated the benefits of heat-stable carotenoid-producing Bacillus marisflavi SH8 spores individually and in combination with non-pigmented Bacillus subtilis SH23 spores on growth, colour change, nutritional content, innate immunity, and gut microbiota of white-leg shrimp. White-leg shrimp (Litopenaeus vannamei; n = 30 per tank; 2 tanks per group) were provided feed without (control group) or with SH8, SH23, or mixed spores (total, 1 × 106 cfu/g pellet) for 28 d. The SH8 and SH8-23 combination groups had significantly higher specific growth rates (9.6 and 11.0%), improved red-colour score (4 scores), astaxanthin concentration (1.8- and 2.3-fold), lipid contents (30 and 50%), and superoxidase dismutase activity (8.5 and 12.3%) than that of the control group. Analysis of shrimp's gut microbiome using 16S rRNA metagenome sequencing revealed increased abundance of four useful species and reduced abundance of four harmful species in the combination group than in the control group. Heat-stable Bacillus spore combination improved growth parameters, nutrient content, red-colour score, live counts, and abundance of useful bacteria in the gut of L. vannamei. This is the first study to show the benefits of combining highly heat-stable pigmented and non-pigmented Bacillus spores and their possible mechanisms in a shrimp model.

Predicting the Progression of Spasticity in the Early Phase of Spinal Cord Injury: A Prospective Cohort Study

Spasticity-defined as involuntary movements caused by insult to upper motor neurons after spinal cord injury (SCI)-interferes with patients' activities of daily living. Spasticity is generally identified and managed in the chronic phase of SCI, but few reports have examined the onset of spasticity after injury. The purpose of this study is to elucidate serial changes in spasticity after SCI and clarify the timing of severe spasticity. We prospectively examined individuals with acute traumatic SCI admitted within two weeks after injury. Severity of spasticity was evaluated using the Modified Ashworth Scale (MAS) at 2, 4, 6, and 8 weeks, followed by 3, 4, 5, and 6 months after injury. After completing evaluation of the cohort, the patients were divided into two groups: a spasticity group with MAS scores ≥3 (marked increase in muscle tone through most of the range of motion (ROM)) in at least one joint movement within 6 months of injury and a control group with MAS scores ≤2 in all joint movements throughout the 6 months after injury. Neurological findings such as the American Spinal Injury Association (ASIA) Impairment Scale grades and ASIA motor scores were also assessed at all time points, and the correlations between the onset of spasticity, severity of spasticity, and neurological findings were analyzed. There were 175 patients with traumatic SCI who were assessed consecutively for 6 months after injury. The MAS scores of the group significantly increased over time until 4 months after injury. The spasticity group had significantly higher MAS scores compared with the control group as early as 2 weeks post-injury. We found that the patients with earlier onset of spasticity had higher final MAS scores. No correlation was found between the ASIA Impairment Scale grade and the onset of spasticity. Our results reveal that the development of severe spasticity may be predictable from as early as 2 weeks after SCI, suggesting that early therapeutic intervention to mitigate problematic spasticity may enhance the benefits of post-injury rehabilitation.

Zinc deficiency impairs axonal regeneration and functional recovery after spinal cord injury by modulating macrophage polarization via NF-κB pathway

Background

Spinal cord injury (SCI) is a devastating disease that results in permanent paralysis. Currently, there is no effective treatment for SCI, and it is important to identify factors that can provide therapeutic intervention during the course of the disease. Zinc, an essential trace element, has attracted attention as a regulator of inflammatory responses. In this study, we investigated the effect of zinc status on the SCI pathology and whether or not zinc could be a potential therapeutic target.

Methods

We created experimental mouse models with three different serum zinc concentration by changing the zinc content of the diet. After inducing contusion injury to the spinal cord of three mouse models, we assessed inflammation, apoptosis, demyelination, axonal regeneration, and the number of nuclear translocations of NF-κB in macrophages by using qPCR and immunostaining. In addition, macrophages in the injured spinal cord of these mouse models were isolated by flow cytometry, and their intracellular zinc concentration level and gene expression were examined. Functional recovery was assessed using the open field motor score, a foot print analysis, and a grid walk test. Statistical analysis was performed using Wilcoxon rank-sum test and ANOVA with the Tukey-Kramer test.

Results

In macrophages after SCI, zinc deficiency promoted nuclear translocation of NF-κB, polarization to pro-inflammatory like phenotype and expression of pro-inflammatory cytokines. The inflammatory response exacerbated by zinc deficiency led to worsening motor function by inducing more apoptosis of oligodendrocytes and demyelination and inhibiting axonal regeneration in the lesion site compared to the normal zinc condition. Furthermore, zinc supplementation after SCI attenuated these zinc-deficiency-induced series of responses and improved motor function.

Conclusion

We demonstrated that zinc affected axonal regeneration and motor functional recovery after SCI by negatively regulating NF-κB activity and the subsequent inflammatory response in macrophages. Our findings suggest that zinc supplementation after SCI may be a novel therapeutic strategy for SCI.

Human Spinal Oligodendrogenic Neural Progenitor Cells Enhance Pathophysiological Outcomes and Functional Recovery in a Clinically Relevant Cervical Spinal Cord Injury Rat Model

Traumatic spinal cord injury (SCI) results in the loss of neurons, oligodendrocytes, and astrocytes. Present interventions for SCI include decompressive surgery, anti-inflammatory therapies, and rehabilitation programs. Nonetheless, these approaches do not offer regenerative solutions to replace the lost cells, fiber tracts, and circuits. Neural stem/progenitor cell (NPC) transplantation is a promising strategy that aims to encourage regeneration. However, NPC differentiation remains inconsistent, thus, contributing to suboptimal functional recovery. As such, we have previously engineered oligodendrogenically biased NPCs (oNPCs) and demonstrated their efficacy in a thoracic model of SCI. Since the majority of patients with SCI experience cervical injuries, our objective in the current study was to generate human induced pluripotent stem cell-derived oNPCs (hiPSC-oNPCs) and to characterize these cells in vitro and in vivo, utilizing a clinically relevant rodent model of cervical SCI. Following transplantation, the oNPCs engrafted, migrated to the rostral and caudal regions of the lesion, and demonstrated preferential differentiation toward oligodendrocytes. Histopathological evaluations revealed that oNPC transplantation facilitated tissue preservation while diminishing astrogliosis. Moreover, oNPC transplantation fostered remyelination of the spared tissue. Functional analyses indicated improved forelimb grip strength, gait, and locomotor function in the oNPC-transplanted rats. Importantly, oNPC transplantation did not exacerbate neuropathic pain or induce tumor formation. In conclusion, these findings underscore the therapeutic potential of oNPCs in promoting functional recovery and histopathological improvements in cervical SCI. This evidence warrants further investigation to optimize and advance this promising cell-based therapeutic approach.

Incidence and risk factors of pneumonia following acute traumatic cervical spinal cord Injury

OBJECTIVES

To elucidate the incidence and risk factors for pneumonia after acute traumatic cervical spinal cord injury (CSCI).

DESIGN

Retrospective cohort study.Setting: Spinal injuries center in Japan.Participants: Of 184 individuals who were admitted within 2 weeks after acute traumatic cervical spinal injuries, 167 individuals who met the criteria were included in this study.Interventions: The occurrence of pneumonia, degree of dysphagia using the Dysphagia Severity Scale, patient age, history of smoking, presence of tracheostomy, vital capacity, level of injury, and the American Spinal Injury Association Impairment Scale (AIS) 2 weeks after injury were assessed.Outcomes: Incidence of pneumonia were analyzed. Moreover, the risk factors of pneumonia were evaluated using logistic regression analysis.

RESULTS

From the 167 individuals who met the criteria, 30 individuals (18%) had pneumonia; in 26 (87%) of these individuals, pneumonia was aspiration related, defined as Dysphagia Severity Scale ≤ 4. The median occurrence of aspiration pneumonia was 11.5 days after injury. A logistic regression analysis revealed that severe AIS and severe Dysphagia Severity Scale scores were significant risk factors of pneumonia after CSCI.

CONCLUSIONS

It was highly likely that the pneumonias following CSCI were related to aspiration based on the Dysphagia Severity Scale. In addition, most of the patients developed aspiration pneumonia within 1 month after injury. Aspiration and severe paralysis were significant risk factors for pneumonia. The treatment of dysphagia in the acute phase should be considered an important indicator to prevent pneumonia.

Time Course and Characteristics of the Nutritional Conditions in Acute Traumatic Cervical Spinal Cord Injury

Introduction

This retrospective cohort study aimed to examine the nutritional time course and elucidate the critical period of undernutrition following acute traumatic cervical spinal cord injury (CSCI).

Methods

The study was performed at a single facility that treated spinal cord injuries. We examined individuals with acute traumatic CSCI admitted to our hospital within 3 days of injury. Both prognostic nutritional index (PNI) and controlling nutritional status (CONUT) scores, which objectively reflect nutritional and immunological conditions, were assessed at admission and 1, 2, and 3 months after the injury. The American Spinal Injury Association impairment scale (AIS) categorizations and severity of dysphagia were evaluated at these time points.

Results

A total of 106 patients with CSCI were evaluated consecutively for 3 months after injury. Individuals with AIS categorizations of A, B, or C at 3 days after injury were significantly more undernourished than those with an AIS categorization of D at 3 months after injury, indicating that individuals with mild paresis better maintained their nutritional condition after injury. Nutritional conditions, as assessed by both PNI and CONUT scores, improved significantly between 1 and 2 months after injury, whereas no significant differences were found between admission and 1 month after injury. Nutritional status and dysphagia were significantly correlated at each time point (p<0.001), indicating that swallowing dysfunction is an important factor associated with malnutrition.

Conclusions

Nutritional conditions showed significant gradual improvements from 1 month after the injury. We must pay attention to undernutrition, which is associated with dysphagia, especially in individuals with severe paralysis during the acute phase following injury.

Diaphragm pacing implantation in Japan for a patient with cervical spinal cord injury: A case report

RATIONALE

Traumatic cervical spinal cord injury (SCI) is a devastating condition leading to respiratory failure that requires permanent mechanical ventilation, which is the main driver of increased medical costs. There is a great demand for establishing therapeutic interventions to treat respiratory dysfunction following severe cervical SCI.

PATIENT CONCERNS AND DIAGNOSIS

We present a 24-year-old man who sustained a cervical displaced C2-C3 fracture with SCI due to a traffic accident. As the patient presented with tetraplegia and difficulty in spontaneous breathing following injury, he was immediately intubated and placed on a ventilator with cervical external fixation by halo orthosis. The patient then underwent open reduction and posterior fusion of the cervical spine 3 weeks after injury. Although the patient showed significant motor recovery of the upper and lower limbs over time, only a slight improvement in lung capacity was observed.

INTERVENTIONS AND OUTCOMES

At 1.5 years after injury, a diaphragmatic pacing stimulator was surgically implanted to support the patient's respiratory function. The mechanical ventilator support was successfully withdrawn from the patient 14 weeks after implantation. We observed that both the vital capacity and tidal volume of the patient were significantly promoted following implantation. The patient finally returned to daily life without any mechanical support.

LESSONS

The findings of this report suggest that diaphragmatic pacing implantation could be a promising treatment for improving respiratory function after severe cervical SCI. To our knowledge, this is the first SCI patient treated with a diaphragm pacing implantation covered by official medical insurance in Japan.

AB0095 CHARACTERISTICS OF TUMOR NECROSIS FACTOR-ALPHA AND INTERLEUKIN-6-INDUCED OSTEOCLASTS IN PERIPHERAL BLOOD AND BONE TISSUE FROM PATIENTS WITH RHEUMATOID ARTHRITIS

Background

We have previously reported that stimulation of mouse bone marrow–derived macrophages with tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) induces differentiation of osteoclast-like cells having bone resorption ability1. Recently, we have shown that the combination of TNF-α and IL-6 can induce osteoclasts from human peripheral blood mononuclear cells (PBMCs) via RANKL-independent pathways, and that there are functional differences between TNF-α and IL-6-induced osteoclasts (T6-OCs) and RANKL-induced, conventional osteoclasts (cOCs). In particular, the number of T6-OCs differentiated from PBMCs in patients with rheumatoid arthritis (RA) positively correlated with the modified total Sharp score (mTSS)2. On the other hands, no such correlation was observed between the number of cOCs from RA and mTSS.

Objectives

Objectives of this study were to compare the differentiational potential into T6-OCs of PBMCs from RA patients with those from healthy donors, to clarify mRNA and protein expressions of T6-OCs derived from PBMCs from patients with RA, and to identify tartrate resistant acid phosphatase (TRACP) positive multinuclear cells with the same characters as T6-OCs histologically in the sub-chondral bone tissues from patients with RA and osteoarthritis (OA).

Methods

PBMCs and CD14+ monocytes derived from RA patients and healthy volunteers were stimulated with TNF-α and IL-6 or RANKL. Real-time quantitative PCR and immunofluorescence staining were used to measure expression levels of osteoclast-associated mRNA and protein. Consecutive sections of the proximal tibial bone tissue from patients with RA and OA (n=6 each) were stained by TRACP, and analyzed expression levels of osteoclast-associated molecules by immunohistochemistry.

Results

The number of T6-OCs differentiated from PBMCs in RA patients was significantly increased compared to that in healthy volunteers. Expression levels of RANK mRNA and protein were clearly up-regulated in cOCs differentiated from CD14+ monocytes and were down-regulated in T6-OCs. In contrast, expression levels of MMP-3 mRNA and protein were obviously up-regulated in T6-OCs and down-regulated in cOCs. Therefore, we believe T6-OCs and cOCs were differently identified on bone tissue as TRACP+RANK-/MMP-3+ cells and TRACP+RANK+/MMP-3- cells, respectively. The numbers of TRACP+ osteoclasts in subchondral cancellous bone were significantly increased in RA patients compared to those in OA patients. Interestingly, numerous TRACP+/RANK-/MMP-3+ osteoclasts were present in the subchondral bone from patients with RA, on the other hands, no such cells observed in OA patients.

Conclusion

The PBMCs of RA patients have definitely increased differentiation capacity into T6-OCs, which have potential of degrading chondral tissue. Additionally, cells having same characteristics with T6-OCs are observed in subchondral bone of patients with RA. These results suggest that novel T6-OCs may be involved in the pathogenic mechanisms of inflammatory bone destruction in patients with RA.

References

[1]Yokota K, Sato K, Miyazaki T, Kitaura H, Kayama H, Miyoshi F, Araki Y, Akiyama Y, Takeda K, Mimura T. Combination of Tumor Necrosis Factor α and Interleukin-6 Induces Mouse Osteoclast-like Cells With Bone Resorption Activity Both in Vitro and In Vivo. Arthritis & Rheumatology Jan;66(1):121-9, 2014.

[2]Yokota K, Sato K, Miyazaki T, Aizaki Y, Tanaka S, Sekikawa M, Kozu N, Kadono Y, Oda H, Mimura T. Characterization and Function of Tumor Necrosis Factor alpha and Interleukin-6-Induced Osteoclasts in Rheumatoid Arthritis. Arthritis & Rheumatology Jul;73(7):1145-1154, 2021.

Acknowledgements

We are grateful to H. Kajiyama and Y. Araki (Saitama Medical University) for helpful discussion.

Disclosure of Interests

None declared

Species-specific debromination of BDE99 in teleost fish: The relationship between debromination ability and bioaccumulation patterns of PBDEs

Polybrominated diphenyl ethers (PBDEs) are known to be broken down by debromination reactions in the natural environment, such as by photolysis, microbial and metabolic processes. Although species-specific debromination of PBDEs by fish has also been reported, it has only rarely been studied from the phylogenetic perspective. The objective of this study is to reveal the factors affecting species-specific debromination through validation between the bioaccumulation of PBDEs in muscle tissue and the ability to debrominate BDE99. As environmental observations, PBDE concentrations in muscle tissues were analyzed in 25 wild fish (Cyprinidae, Gobiidae and others). As in vitro experiments, debromination experiments were conducted using the hepatic microsomes of 21 fish species. Significant amounts of BDE99 were detected in almost none of the Cyprinidae. A relatively higher debromination ability was confirmed in the Cyprinidae in in vitro experiments. The Cyprinidae thus appears to be a family with high debromination ability. BDE99 has been detected in some goby species but not others. This pattern was also seen in in vitro experiments, suggesting that debromination ability is not consistent within the Gobiidae. In further quantitative comparisons, kinetic parameters such as K_m and v_max were determined for selected fish species. The common carp (Cyprinus carpio) and the Japanese crucian carp (Carassius cuvieri), both Cyprinidae, showed higher v_max values, whereas v_max values among three Gobiidae diverged widely. A comparison of field observations and in vitro experiments, revealed the bioaccumulation ratio of BDE99 to be affected by the BDE99 debromination ability of each fish species. This is the first report on classification of BDE99 accumulation ratio by debromination ability and a phylogenetic species comparison based on kinetic parameters for debromination reactions of PBDEs by fish.

Significance of the neurological level of injury as a prognostic predictor for motor complete cervical spinal cord injury patients

OBJECTIVE

To investigate the usefulness of the combination of neurological findings and magnetic resonance imaging (MRI) as a prognostic predictor in patients with motor complete cervical spinal cord injury (CSCI) in the acute phase.

DESIGN

A cross-sectional analysis.

SETTING

Department of Orthopaedic Surgery, Spinal Injuries Center.

PARTICIPANTS/METHODS

Forty-two patients with an initial diagnosis of motor complete CSCI (AIS A, n = 29; AIS B, n = 13) within 72 h after injury were classified into the recovery group (Group R) and the non-recovery group (Group N), based on the presence or absence of motor recovery (conversion from AIS A/B to C/D) at three months after injury, respectively. The Neurological Level of Injury (NLI) at the initial diagnosis was investigated and the presumptive primary injured segment of the spinal cord was inferred from MRI performed at the initial diagnosis. We investigated whether or not the difference between the presumptive primary injured segment and the NLI exceeded one segment. The presence of a difference between the presumptive primary injured segment and the NLI was compared between Groups R and N.

RESULTS

The number of cases with the differences between the presumptive primary injured segment and the NLI was significantly higher in Group N than in Group R.

CONCLUSION

The presence of differences between the presumptive primary injured segment and the NLI might be a poor improving prognostic predictor for motor complete CSCI. The NLI may be useful for predicting the recovery potential of patients with motor complete CSCI when combined with the MRI findings.

Long-term outcomes of spinal meningioma resection with outer layer of dura preservation technique

Spinal meningioma is a common benign intradural spinal tumor. It has been reported that the local recurrence rate after surgical resection increases with longer follow-up duration. Simpson grade 1 resection could reduce the risk of recurrence, but this procedure needs dural reconstruction, which would cause cerebrospinal fluid (CSF) leakage or iatrogenic spinal cord injury. Saito et al. reported dura preservation technique to reduce the risk of CSF leakage, in which the meningioma together with the inner layer of the dura is removed and the outer layer is preserved for simple dural closure. The long-term outcomes with this technique have never been investigated. In this study, we retrospectively analyzed the data of 38 surgically treated patients (dura preservation technique, 12 patients; Simpson grade 2 resection, 26 patients) to assess the long-term recurrence rate (mean, 121.5 months; range, 60-228 months). The local recurrence rate in the dura preservation group was 8.3% (1 of 12 cases), which was similar to that in Simpson grade 2 resection group (2 of 26 cases [7.7%]). Although this case series did not indicate the significant difference in the recurrence rates between the dura preservation group and Simpson grade 2 group, we consider that this technique still has advantages for surgically less invasiveness in terms of dural reconstruction which is necessary for Simpson grade 1 and higher possibility of complete resection of tumors compared with Simpson grade 2 resection.

Acute spinal subdural hematoma: A case report of spontaneous recovery from paraplegia

RATIONALE

Spontaneous spinal subdural hematoma (SSDH) is a rare disease that can cause severe permanent neurological dysfunction. Here we present a case of spontaneous SSDH, in which a series of magnetic resonance images (MRIs) taken through the course of the disease facilitated understanding of the resolution process of the hematoma and the diagnosis of SSDH.

PATIENT CONCERNS

A 59-year-old male presented with sudden severe back pain and rapid onset of paraplegia. This symptom had continued developing while he was transferred to the emergency department. Initial physical examination showed flaccid paralysis of both lower limbs with areflexia and loss of all sensation below T6 bilaterally. MRI images showed an anterior subdural hematoma from C7 to T7 with spinal cord compression.

DIAGNOSIS

Based on MRI findings, the diagnosis was SSDH.

INTERVENTIONS

We chose conservative treatment of 1-week bed rest and intensive rehabilitation for the patient due to the presence of sacral sparing and the slight motor recovery at 24 hours after the onset.

OUTCOMES

Frequent MRI images demonstrated that the spinal cord compression was surprisingly mitigated only 2 days and mostly absorbed 4 days after the onset. The patient's motor function was recovered completely and he was discharged after 8 weeks of hospitalization.

LESSONS

Our chronological MRI findings provide crucial information for diagnosing SSDH and also suggest that spinal surgeons should consider the potential option of a conservative approach for treating SSDH. Although prompt selection of a therapeutic strategy for SSDH could be challenging, the surgeons could observe the course of the patient's neurological status for a few days to detect signs of spontaneous recovery.

EFFECT OF PREGNANCY ON LOWER LIMB LYMPHEDEMA IN PATIENTS TREATED WITH MULTISITE LYMPHATICOVENULAR ANASTOMOSES (MLVAS)

Lymphaticovenular anastomosis (LVA) using supermicrosurgical techniques is effective for treating and preventing progression of lymphedema. We analyzed the influence of pregnancy on LVA in five patients from a total 2179 LVA cases. Previous studies offer conflicting reports on whether pregnancy worsens pre-existing lymphedema. This is the first report on the influence of pregnancy on lower limb lymphedema previously treated by multisite LVA (mLVA). Five patients with primary (n=4) and secondary (n=1) lower leg lymphedema were analyzed for this study. Patient age ranged from 18 to 31 (average 22.6) years old with 4 right and 1 left extremities involved. Duration of symptoms ranged from one to 19 (average 7.4) years and the periods of compression therapy were from 1 to 19 years (6.6 years). Four patients had single pregnancies and one patient was multiparous with 3 pregnancies. Final follow-up ranged from 5.8 to 18 years (average 8.9 years) after the primary mLVA. All patients had normal pregnancy, birth, and no serious complications after surgeries. Following pregnancy three patients had complete functional recovery (limb volume reduction and no compression requirement), one with functional improvement (limb volume reduction but required compression), and one with no change in symptoms (not worse and continued need for compression). There were no occurrences of infection following pregnancy. Based on this case series, it is suggested that pregnancy does not worsen the pre-existing lymphedema in patients who had previously undergone mLVA. Further studies with larger number of patients are needed to confirm these results.

The beneficial aspects of spasticity in relation to ambulatory ability in mice with spinal cord injury

STUDY DESIGN

Experimental study with mice.

OBJECTIVES

Spasticity is a common complication after spinal cord injury (SCI) and has detrimental aspects, such as persistent pain and involuntary muscle spasms. This study aimed to assess the influence of antispastic therapy on locomotor function after SCI.

SETTING

University-based laboratory in Fukuoka, Japan.

METHODS

A mouse model of spasticity was developed by producing incomplete SCI at the 9th thoracic level. At 8 weeks after SCI, an antispastic drug, baclofen, was intraperitoneally administered to six injured and two sham-operated mice. The severity of spasticity was evaluated by the modified Ashworth scoring (MAS) system, and locomotor function was evaluated by the Basso-Beattie-Bresnahan (BBB) scale/Basso mouse score (BMS).

RESULTS

The administration of baclofen significantly improved spasticity in the SCI mice and the mean MAS decreased to from 6.2 to 2.8. However, at the same time, it significantly exacerbated the locomotor dysfunction of the SCI mice and the mean BMS decreased from 4.7 to 2.3. The time-course of the changes in locomotor function coincided with the time-course of the spasticity score. We also confirmed that the administration of baclofen was not associated with any changes in either locomotor function or spasticity of the sham-operated control mice.

CONCLUSIONS

Our results suggest that spasticity has a certain beneficial effect on ambulation ability. It is important to note that antispastic treatments may be associated with a risk of impairing the preserved function of chronic SCI patients.

Regeneration of Spinal Cord Connectivity Through Stem Cell Transplantation and Biomaterial Scaffolds

Significant progress has been made in the treatment of spinal cord injury (SCI). Advances in post-trauma management and intensive rehabilitation have significantly improved the prognosis of SCI and converted what was once an “ailment not to be treated” into a survivable injury, but the cold hard fact is that we still do not have a validated method to improve the paralysis of SCI. The irreversible functional impairment of the injured spinal cord is caused by the disruption of neuronal transduction across the injury lesion, which is brought about by demyelination, axonal degeneration, and loss of synapses. Furthermore, refractory substrates generated in the injured spinal cord inhibit spontaneous recovery. The discovery of the regenerative capability of central nervous system neurons in the proper environment and the verification of neural stem cells in the spinal cord once incited hope that a cure for SCI was on the horizon. That hope was gradually replaced with mounting frustration when neuroprotective drugs, cell transplantation, and strategies to enhance remyelination, axonal regeneration, and neuronal plasticity demonstrated significant improvement in animal models of SCI but did not translate into a cure in human patients. However, recent advances in SCI research have greatly increased our understanding of the fundamental processes underlying SCI and fostered increasing optimism that these multiple treatment strategies are finally coming together to bring about a new era in which we will be able to propose encouraging therapies that will lead to appreciable improvements in SCI patients. In this review, we outline the pathophysiology of SCI that makes the spinal cord refractory to regeneration and discuss the research that has been done with cell replacement and biomaterial implantation strategies, both by itself and as a combined treatment. We will focus on the capacity of these strategies to facilitate the regeneration of neural connectivity necessary to achieve meaningful functional recovery after SCI.

Macrophage centripetal migration drives spontaneous healing process after spinal cord injury

Traumatic spinal cord injury (SCI) brings numerous inflammatory cells, including macrophages, from the circulating blood to lesions, but pathophysiological impact resulting from spatiotemporal dynamics of macrophages is unknown. Here, we show that macrophages centripetally migrate toward the lesion epicenter after infiltrating into the wide range of spinal cord, depending on the gradient of chemoattractant C5a. However, macrophages lacking interferon regulatory factor 8 (IRF8) cannot migrate toward the epicenter and remain widely scattered in the injured cord with profound axonal loss and little remyelination, resulting in a poor functional outcome after SCI. Time-lapse imaging and P2X/YRs blockade revealed that macrophage migration via IRF8 was caused by purinergic receptors involved in the C5a-directed migration. Conversely, pharmacological promotion of IRF8 activation facilitated macrophage centripetal movement, thereby improving the SCI recovery. Our findings reveal the importance of macrophage centripetal migration via IRF8, providing a novel therapeutic target for central nervous system injury.

Progression of local kyphosis after conservative treatment for compressive cervical spine fracture with spinal cord injury

Introduction

Compressive-flexion type cervical spine fracture is typically accompanied by apparent dislocation of the facet joints, undesirable cervical alignment, and devastating neurological dysfunction, which provides strong rationale for rendering prompt operative treatment. However, the validity of conservative treatment for compressive-flexion cervical spine injury in cases with preserved congruity of the facet joints has yet to be elucidated. The purpose of this study is to evaluate the long-term outcome of cervical alignment following conservative treatment for compressive-flexion cervical spine injury with preserved congruity of the facet joints.

Methods

A total of 662 patients who experienced spinal cord injury from 2007 to 2017 were included and underwent retrospective review in a single institute. Thirteen patients were identified as receiving conservative therapy following compressive-flexion cervical spine fractures with spinal cord injury. Clinical and radiological results were collected, including vertical fractures of the vertebral column, laminar fractures, progression of local kyphosis, and neurological status. The degree of the local cervical kyphosis was evaluated with two methods: the posterior tangent method and the endplate method.

Results

All 13 patients were male, and the mean age at the time of injury was 28.4 years. The mean follow-up period was 3 years. Although none of the patients presented neurological deterioration after the injury, the degree of local kyphosis was increased at the time of final follow-up compared to what was observed at the time of injury. Patient age at the time of injury and concurrent vertical fracture of vertebral body could have been influencing factors for the progression of the kyphosis. While laminar fracture affected the kyphosis at the time of injury, it was not a strong influencing factor of the overall progression of local kyphosis.

Conclusions

The conservative option for the compressive-flexion cervical injury allowed us to treat without exacerbating neurological symptoms as long as the facet joints are preserved. However, in terms of cervical alignment, surgical stabilization may have been desirable for these patients. Notably, the younger patients and the patients with vertical fracture of the cervical vertebral column in this type of injury required closer observation to help prevent the progression of local kyphosis.

The acute phase serum zinc concentration is a reliable biomarker for predicting the functional outcome after spinal cord injury

Background

Spinal cord injury (SCI) is a devastating disorder for which the accurate prediction of the functional prognosis is urgently needed. Due to the lack of reliable prediction methods, the acute evaluation of SCI severity and therapeutic intervention efficacy is extremely difficult, presenting major obstacles to the development of acute SCI treatment. We herein report a novel method for accurately predicting the functional prognosis using the acute-phase serum zinc concentration after SCI.

Methods

We produced experimental animal SCI models with different prognoses and examined the relationship among the SCI severity, functional outcome, and acute-phase serum zinc concentration. We also examined whether we could predict the functional prognosis by evaluating the serum zinc concentration within 72 h after SCI in a human prospective study.

Findings

In a mouse model, the acute serum zinc concentrations decreased in proportion to SCI severity and the serum zinc concentrations at 12 h after SCI accurately predicted the functional prognosis. We clarified the mechanism underlying this serum zinc proportional decrease, showing that activated monocytes took up zinc from blood-serum and then infiltrated the lesion area in a severity-dependent manner. A non-linear regression analysis of 38 SCI patients showed that the serum zinc concentrations in the acute-phase accurately predicted the long-term functional outcome (R² = 0·84) more accurately than any other previously reported acute-phase biomarkers.

Interpretation

The acute-phase serum zinc concentration could be a useful biomarker for predicting the functional prognosis. This simple method will allow for more objective clinical trials and the development of patient-tailored treatment for SCI.

Pathological changes of distal motor neurons after complete spinal cord injury

Traumatic spinal cord injury (SCI) causes serious disruption of neuronal circuits that leads to motor functional deficits. Regeneration of disrupted circuits back to their original target is necessary for the restoration of function after SCI, but the pathophysiological condition of the caudal spinal cord has not been sufficiently studied. Here we investigated the histological and biological changes in the distal part of the injured spinal cord, using a mice model of complete thoracic SCI in the chronic stage (3 months after injury). Atrophic changes were widely observed in the injured spinal cord both rostral and caudal to the lesion, but the decrease in area was mainly in the white matter in the rostral spinal cord while both the white and gray matter decreased in the caudal spinal cord. The number of the motor neurons was maintained in the chronic phase of injury, but the number of presynaptic boutons decreased in the lumbar motor neurons caudal to the lesion. Using laser microdissection, to investigate gene expressions in motor neurons caudal to the lesion, we observed a decrease in the expressions of neuronal activity markers. However, we found that the synaptogenic potential of postsynapse molecules was maintained in the motor neurons after SCI with the expression of acetylcholine-related molecules actually higher after SCI. Collectively, our results show that the potential of synaptogenesis is maintained in the motor neurons caudal to the lesion, even though presynaptic input is decreased. Although researches into SCI concentrate their effort on the lesion epicenter, our findings suggest that the area caudal to the lesion could be an original therapeutic target for the chronically injured spinal cord.

Effect of pregnancy on lower limb lymphedema in patients treated with multisite lymphaticovenular anastomoses (MLVAS)

Lymphaticovenular anastomosis (LVA) using supermicrosurgical techniques is effective for treating and preventing progression of lymphedema. We analyzed the influence of pregnancy on LVA in five patients from a total 2179 LVA cases. Previous studies offer conflicting reports on whether pregnancy worsens pre-existing lymphedema. This is the first report on the influence of pregnancy on lower limb lymphedema previously treated by multisite LVA (mLVA). Five patients with primary (n=4) and secondary (n=1) lower leg lymphedema were analyzed for this study. Patient age ranged from 18 to 31 (average 22.6) years old with 4 right and 1 left extremities involved. Duration of symptoms ranged from one to 19 (average 7.4) years and the periods of compression therapy were from 1 to 19 years (6.6 years). Four patients had single pregnancies and one patient was multiparous with 3 pregnancies. Final follow-up ranged from 5.8 to 18 years (average 8.9 years) after the primary mLVA. All patients had normal pregnancy, birth, and no serious complications after surgeries. Following pregnancy three patients had complete functional recovery (limb volume reduction and no compression requirement), one with functional improvement (limb volume reduction but required compression), and one with no change in symptoms (not worse and continued need for compression). There were no occurrences of infection following pregnancy. Based on this case series, it is suggested that pregnancy does not worsen the pre-existing lymphedema in patients who had previously undergone mLVA. Further studies with larger number of patients are needed to confirm these results.

What are the risk factors for postoperative infections of third molar extraction surgery: A retrospective clinical study?

BACKGROUND

This study aimed to identify (1) the predilection site of postoperative infection after third molar extraction surgery, (2) risk factors associated with postoperative infection, and (3) the cause of the difference between delayed- and early-onset infections.

MATERIALS AND METHODS

This retrospective study included 1010 patients (396 male, 614 female) who had ≥1 third molars extracted (2407; 812 maxilla, 1595 mandible). The risk factors were classified as attributes, general health, anatomic, and operative. Outcome variables were delayed- and early-onset infections.

RESULTS

Postoperative infection was completely absent in the maxilla, and all infections occurred in the mandible, with a probability of 1.94% (31/1595). Bivariate analysis for postoperative infection showed depth of inclusion and intraoperative hemostatic treatment to be significantly associated with the development of infections. Bivariate analysis for delayed- and early-onset infections showed simultaneous extraction of the left and right mandibular third molars to be prominent risk factors.

CONCLUSIONS

Postoperative infection occurs mainly in the mandible, and that in the maxilla is very rare. The risk of postoperative infection in the mandible was found to be related to the depth of inclusion and intraoperative hemostatic treatment. Simultaneous extraction of the left and right mandibular third molars appear to increase the risk of delayed-onset postoperative infection.

Human Oligodendrogenic Neural Progenitor Cells Delivered with Chondroitinase ABC Facilitate Functional Repair of Chronic Spinal Cord Injury

Treatment of chronic spinal cord injury (SCI) is challenging due to cell loss, cyst formation, and the glial scar. Previously, we reported on the therapeutic potential of a neural progenitor cell (NPC) and chondroitinase ABC (ChABC) combinatorial therapy for chronic SCI. However, the source of NPCs and delivery system required for ChABC remained barriers to clinical application. Here, we investigated directly reprogrammed human NPCs biased toward an oligodendrogenic fate (oNPCs) in combination with sustained delivery of ChABC using an innovative affinity release strategy in a crosslinked methylcellulose biomaterial for the treatment of chronic SCI in an immunodeficient rat model. This combinatorial therapy increased long-term survival of oNPCs around the lesion epicenter, facilitated greater oligodendrocyte differentiation, remyelination of the spared axons by engrafted oNPCs, enhanced synaptic connectivity with anterior horn cells and neurobehavioral recovery. This combinatorial therapy is a promising strategy to regenerate the chronically injured spinal cord.

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Sustained biomaterial delivery of ChABC successfully degraded CSPGs

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XMC-ChABC promoted differentiation of oNPCs to more oligodendrocytes

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XMC-ChABC increased the long-term survival and integration of grafted oNPCs

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XMC-ChABC and oNPC combinatorial therapy is a promising treatment for chronic SCI

Periostin Promotes Fibroblast Migration and Inhibits Muscle Repair After Skeletal Muscle Injury

BACKGROUND

Skeletal muscle injury (SMI) can cause physical disability due to insufficient recovery of the muscle. The development of muscle fibrosis after SMI has been widely regarded as a principal cause of this failure to recover. Periostin (Postn) exacerbates tissue fibrosis in various organs. We investigated whether Postn is involved in the pathophysiology after SMI.

METHODS

Partial laceration injuries of the gastrocnemius were created in wild-type (WT) and Postn knockout (Postn) mice. We examined the expression of the Postn gene before and after SMI. Regeneration and fibrosis of skeletal muscle were evaluated by histological analyses, and recovery of muscle strength was measured by physiological testing. Immunohistochemistry was used to examine the number and proliferative potential of infiltrating fibroblasts in injured muscle. A trans-well migration assay was used to assess the migration capability of fibroblasts. Control immunoglobulin G (IgG) or Postn-neutralizing antibody (Postn-nAb) was injected into injured muscle at 7 and 14 days after injury (dpi). We evaluated the effects of Postn-nAb on muscle repair after SMI.

RESULTS

The expression of Postn was dramatically upregulated after SMI. Compared with WT mice, Postn mice had improved muscle recovery and attenuated fibrosis as well as a significantly reduced number of infiltrating fibroblasts. The proliferative potential of these fibroblasts in WT and Postn mice was comparable at 14 dpi; however, the migration capability of fibroblasts was significantly enhanced in the presence of Postn (mean, 258%; 95% confidence interval, 183% to 334%). Moreover, the administration of Postn-nAb inhibited fibroblast infiltration and promoted muscle repair after SMI.

CONCLUSIONS

Postn exacerbates fibrotic scar formation through the promotion of fibroblast migration into injured muscle after SMI. Treatment with Postn-nAb is effective for attenuating fibrosis and improving muscle recovery after SMI.

CLINICAL RELEVANCE

Our findings may provide a potential therapeutic strategy to enhance muscle repair and functional recovery after SMI.

Use of ATP bioluminescence to survey the spread of aerosol and splatter during dental treatments

Aerosol and splatter produced during dental treatments (ultrasonic scaling and professional mechanical tooth cleaning) are potential sources of infection. Contamination patterns on the mask, goggles, chest and gowned right arm of operators, and on the goggles of patients before and after dental treatments were investigated using ATP bioluminescence analysis. Contamination on every surface tested increased significantly after dental treatment. Maximum contamination was found on the goggles of patients. Aerosol and splatter produced during dental treatments therefore have the potential to spread infection to operators and patients. ATP bioluminescence is a useful tool for monitoring surface contamination.

The correlation of urinary podocytes and podocalyxin with histological features of lupus nephritis

Objectives The objective of this study was to test the correlation of urinary podocyte number (U-Pod) and urinary podocalyxin levels (U-PCX) with histology of lupus nephritis. Methods This was an observational, cross-sectional study. Sixty-four patients were enrolled: 40 with lupus nephritis and 24 without lupus nephritis (12 lupus nephritis patients in complete remission and 12 systemic lupus erythematosus patients without lupus nephritis). Urine samples were collected before initiating treatment. U-Pod was determined by counting podocalyxin-positive cells, and U-PCX was measured by sandwich ELISA, normalized to urinary creatinine levels (U-Pod/Cr, U-PCX/Cr). Results Lupus nephritis patients showed significantly higher U-Pod/Cr and U-PCX/Cr compared with patients without lupus nephritis. U-Pod/Cr was high in proliferative lupus nephritis (class III±V/IV±V), especially in pure class IV (4.57 (2.02-16.75)), but low in pure class V (0.30 (0.00-0.71)). U-Pod/Cr showed a positive correlation with activity index ( r=0.50, P=0.0012) and was independently associated with cellular crescent formation. In contrast, U-PCX/Cr was high in both proliferative and membranous lupus nephritis. Receiver operating characteristic analysis revealed significant correlation of U-Pod/Cr with pure class IV, class IV±V and cellular crescent formation, and the combined values of U-Pod/Cr and U-PCX/Cr were shown to be associated with pure class V. Conclusions U-Pod/Cr and U-PCX/Cr correlate with histological features of lupus nephritis.

Macrophage Infiltration Is a Causative Factor for Ligamentum Flavum Hypertrophy through the Activation of Collagen Production in Fibroblasts

Ligamentum flavum (LF) hypertrophy causes lumbar spinal canal stenosis, leading to leg pain and disability in activities of daily living in elderly individuals. Although previous studies have been performed on LF hypertrophy, its pathomechanisms have not been fully elucidated. In this study, we demonstrated that infiltrating macrophages were a causative factor for LF hypertrophy. Induction of macrophages into the mouse LF by applying a microinjury resulted in LF hypertrophy along with collagen accumulation and fibroblasts proliferation at the injured site, which were very similar to the characteristics observed in the severely hypertrophied LF of human. However, we found that macrophage depletion by injecting clodronate-containing liposomes counteracted LF hypertrophy even with microinjury. For identification of fibroblasts in the LF, we used collagen type I α₂ linked to green fluorescent protein transgenic mice and selectively isolated green fluorescent protein-positive fibroblasts from the microinjured LF using laser microdissection. A quantitative RT-PCR on laser microdissection samples revealed that the gene expression of collagen markedly increased in the fibroblasts at the injured site with infiltrating macrophages compared with the uninjured location. These results suggested that macrophage infiltration was crucial for LF hypertrophy by stimulating collagen production in fibroblasts, providing better understanding of the pathophysiology of LF hypertrophy.

Interaction of reactive astrocytes with type I collagen induces astrocytic scar formation through the integrin-N-cadherin pathway after spinal cord injury

Central nervous system (CNS) injury transforms naive astrocytes into reactive astrocytes, which eventually become scar-forming astrocytes that can impair axonal regeneration and functional recovery. This sequential phenotypic change, known as reactive astrogliosis, has long been considered unidirectional and irreversible. However, we report here that reactive astrocytes isolated from injured spinal cord reverted in retrograde to naive astrocytes when transplanted into a naive spinal cord, whereas they formed astrocytic scars when transplanted into injured spinal cord, indicating the environment-dependent plasticity of reactive astrogliosis. We also found that type I collagen was highly expressed in the spinal cord during the scar-forming phase and induced astrocytic scar formation via the integrin-N-cadherin pathway. In a mouse model of spinal cord injury, pharmacological blockade of reactive astrocyte-type I collagen interaction prevented astrocytic scar formation, thereby leading to improved axonal regrowth and better functional outcomes. Our findings reveal environmental cues regulating astrocytic fate decisions, thereby providing a potential therapeutic target for CNS injury.

Periostin Promotes Scar Formation through the Interaction between Pericytes and Infiltrating Monocytes/Macrophages after Spinal Cord Injury

Scar formation is a prominent pathological feature of traumatic central nervous system (CNS) injury, which has long been implicated as a major impediment to the CNS regeneration. However, the factors affecting such scar formation remain to be elucidated. We herein demonstrate that the extracellular matrix protein periostin (POSTN) is a key player in scar formation after traumatic spinal cord injury (SCI). Using high-throughput RNA sequencing data sets, we found that the genes involved in the extracellular region, such as POSTN, were significantly expressed in the injured spinal cord. The expression of POSTN peaked at 7 days after SCI, predominantly in the scar-forming pericytes. Notably, we found that genetic deletion of POSTN in mice reduced scar formation at the lesion site by suppressing the proliferation of the pericytes. Conversely, we found that recombinant POSTN promoted the migration capacity of the monocytes/macrophages and increased the expression of tumor necrosis factor-α from the monocytes/macrophages in vitro, which facilitated the proliferation of pericytes. Furthermore, we revealed that the pharmacological blockade of POSTN suppressed scar formation and improved the long-term functional outcome after SCI. Our findings suggest a potential mechanism whereby POSTN regulates the scar formation after SCI and provide significant evidence that POSTN is a promising therapeutic target for CNS injury.

Experimental Mouse Model of Lumbar Ligamentum Flavum Hypertrophy

Lumbar spinal canal stenosis (LSCS) is one of the most common spinal disorders in elderly people, with the number of LSCS patients increasing due to the aging of the population. The ligamentum flavum (LF) is a spinal ligament located in the interior of the vertebral canal, and hypertrophy of the LF, which causes the direct compression of the nerve roots and/or cauda equine, is a major cause of LSCS. Although there have been previous studies on LF hypertrophy, its pathomechanism remains unclear. The purpose of this study is to establish a relevant mouse model of LF hypertrophy and to examine disease-related factors. First, we focused on mechanical stress and developed a loading device for applying consecutive mechanical flexion-extension stress to the mouse LF. After 12 weeks of mechanical stress loading, we found that the LF thickness in the stress group was significantly increased in comparison to the control group. In addition, there were significant increases in the area of collagen fibers, the number of LF cells, and the gene expression of several fibrosis-related factors. However, in this mecnanical stress model, there was no macrophage infiltration, angiogenesis, or increase in the expression of transforming growth factor-β1 (TGF-β1), which are characteristic features of LF hypertrophy in LSCS patients. We therefore examined the influence of infiltrating macrophages on LF hypertrophy. After inducing macrophage infiltration by micro-injury to the mouse LF, we found excessive collagen synthesis in the injured site with the increased TGF-β1 expression at 2 weeks after injury, and further confirmed LF hypertrophy at 6 weeks after injury. Our findings demonstrate that mechanical stress is a causative factor for LF hypertrophy and strongly suggest the importance of macrophage infiltration in the progression of LF hypertrophy via the stimulation of collagen production.

Monitoring of bacterial contamination of dental unit water lines using adenosine triphosphate bioluminescence

Bacterial contamination of dental unit waterlines (DUWLs) was evaluated using ATP bioluminescence analysis and a conventional culture method. Water samples (N=44) from DUWLs were investigated for heterotrophic bacteria by culture on R2A agar, which gave counts ranging from 1.4×10³ to 2.7×10⁵ cfu/mL. The ATP bioluminescence results for DUWL samples ranged from 6 to 1189 relative light units and could be obtained within 1min; these correlated well with the culture results (r=0.727-0.855). We conclude that the results of the ATP bioluminescence assay accurately reflect the results of conventional culture-based testing. This method is potentially useful for rapid and simple monitoring of DUWL bacterial contamination.

The feasibility of in vivo imaging of infiltrating blood cells for predicting the functional prognosis after spinal cord injury

After a spinal cord injury (SCI), a reliable prediction of the potential functional outcome is essential for determining the optimal treatment strategy. Despite recent advances in the field of neurological assessment, there is still no satisfactory methodology for predicting the functional outcome after SCI. We herein describe a novel method to predict the functional outcome at 12 hours after SCI using in vivo bioluminescence imaging. We produced three groups of SCI mice with different functional prognoses: 50 kdyn (mild), 70 kdyn (moderate) and 90 kdyn (severe). Only the locomotor function within 24 hours after SCI was unable to predict subsequent functional recovery. However, both the number of infiltrating neutrophils and the bioluminescence signal intensity from infiltrating blood cells were found to correlate with the severity of the injury at 12 hours after SCI. Furthermore, a strong linear relationship was observed among the number of infiltrating neutrophils, the bioluminescence signal intensity, and the severity of the injury. Our findings thus indicate that in vivo bioluminescence imaging is able to accurately predict the long-term functional outcome in the hyperacute phase of SCI, thereby providing evidence that this imaging modality could positively contribute to the future development of tailored therapeutic approaches for SCI.