Spinal cord injury: association with axonal peripheral neuropathy in severely paralysed limbs

Magnetic resonance neurography in spinal cord injury: Imaging findings and clinical significance

BACKGROUND AND PURPOSE

It is unknown whether changes to the peripheral nervous system following spinal cord injury (SCI) are relevant for functional recovery or the development of neuropathic pain below the level of injury. Magnetic resonance neurography (MRN) at 3 T allows detection and localization of structural and functional nerve damage. This study aimed to combine MRN and clinical assessments in individuals with chronic SCI and nondisabled controls.

METHODS

Twenty participants with chronic SCI and 20 controls matched for gender, age, and body mass index underwent MRN of the L5 dorsal root ganglia (DRG) and the sciatic nerve. DRG volume, sciatic nerve mean cross-sectional area (CSA), fascicular lesion load, and fractional anisotropy (FA), a marker for functional nerve integrity, were calculated. Results were correlated with clinical assessments and nerve conduction studies.

RESULTS

Sciatic nerve CSA and lesion load were higher (21.29 ± 5.82 mm2 vs. 14.08 ± 4.62 mm2 , p < 0.001; and 8.70 ± 7.47% vs. 3.60 ± 2.45%, p < 0.001) in individuals with SCI compared to controls, whereas FA was lower (0.55 ± 0.11 vs. 0.63 ± 0.08, p = 0.022). DRG volumes were larger in individuals with SCI who suffered from neuropathic pain compared to those without neuropathic pain (223.7 ± 53.08 mm3 vs. 159.7 ± 55.66 mm3 , p = 0.043). Sciatic MRN parameters correlated with electrophysiological results but did not correlate with the extent of myelopathy or clinical severity of SCI.

CONCLUSIONS

Individuals with chronic SCI are subject to a decline of structural peripheral nerve integrity that may occur independently from the clinical severity of SCI. Larger volumes of DRG in SCI with neuropathic pain support existing evidence from animal studies on SCI-related neuropathic pain.

Elevated high-sensitivity cardiac troponin T serum concentration in subjects with spinal cord injury

BACKGROUND

The biochemical analysis of high-sensitivity cardiac troponins (hs-cTn) from peripheral blood specimens has been established as biomarker for myocardial injury. Independently of myocardial injury, increased serum hs-cTn concentrations have been described in patients with myopathies. The relevance and frequency of noncardiac hs-cTn elevations in spinal cord injury (SCI) is unknown. Our study aimed to 1) determine the frequency of increased hs-cTn concentrations of supposedly noncardiac origin above the 99th percentile (upper reference limit, URL) in an unselected SCI population and 2) compare the two protagonist analytes cTnT and cTnI with respect to these noncardiac elevations.

METHODS

In this monocentric, cross-sectional study, we sampled blood from n = 30 SCI subjects without cardiac symptoms to test for hs-cTnT and hs-cTnI serum concentrations.

RESULTS

18/30 (60%) of SCI subjects showed increased hs-cTnT concentrations above the URL of 14 ng/l (p < 0.001). In 4 subjects (22.2%) concentrations were >50 ng/l. Moreover, 3 of these four subjects fulfilled the 6-h troponin dynamics criterion for acute myocardial injury in serial hs-cTnT testing. In contrast, no subject demonstrated increased hs-cTnI concentrations according to the URL of 40 ng/l. 6-h troponin dynamics were also unremarkable for hs-cTnI testing.

CONCLUSIONS

SCI subjects frequently have increased hs-cTnT concentrations without clinical and hs-cTnI evidence of myocardial injury. Clinicians must be aware of cTnT "skeletal muscle false-positives" in SCI, which applies to elevated baseline cTnT concentrations and troponin dynamics in serial measurements. In case of diagnostic uncertainty, simultaneous analysis of cTnI might be helpful.

Double crosslinked biomimetic composite hydrogels containing topographical cues and WAY-316606 induce neural tissue regeneration and functional recovery after spinal cord injury

Spinal cord injury (SCI) is an overwhelming and incurable disabling condition, for which increasing forms of multifunctional biomaterials are being tested, but with limited progression. The promising material should be able to fill SCI-induced cavities and direct the growth of new neurons, with effective drug loading to improve the local micro-organism environment and promote neural tissue regeneration. In this study, a double crosslinked biomimetic composite hydrogel comprised of acellularized spinal cord matrix (ASCM) and gelatin-acrylated-β-cyclodextrin-polyethene glycol diacrylate (designated G-CD-PEGDA) hydrogel, loaded with WAY-316606 to activate canonical Wnt/β-catenin signaling, and reinforced by a bundle of three-dimensionally printed aligned polycaprolactone (PCL) microfibers, was constructed. The G-CD-PEGDA component endowed the composite hydrogel with a dynamic structure with a self-healing capability which enabled cell migration, while the ASCM component promoted neural cell affinity and proliferation. The diffusion of WAY-316606 could recruit endogenous neural stem cells and improve neuronal differentiation. The aligned PCL microfibers guided neurite elongation in the longitudinal direction. Animal behavior studies further showed that the composite hydrogel could significantly recover the motor function of rats after SCI. This study provides a proficient approach to produce a multifunctional system with desirable physiological, chemical, and topographical cues for treating patients with SCI.

Peripheral Neuropathy in the Lower Limbs of Individuals With Spinal Cord Injury or Disease: A Retrospective Study

PURPOSE

This study investigated the frequency and types of peripheral neuropathy in the lower limbs of patients undergoing rehabilitation after traumatic spinal cord injury or spinal cord disease.

METHODS

This study included consecutive patients with spinal cord injury/spinal cord disease who had electrophysiological assessments during their admission in a rehabilitation center from October 2015 to July 2019. Patients with traumatic spinal cord injury were compared with patients with nontraumatic spinal cord disease.

RESULTS

There were 67 patients (52 male patients, 15 female patients; mean age = 56.5 yrs) of whom 36 patients had spinal cord injury and 31 patients had spinal cord disease. Most of the patients were middle-aged men with at least one preexisting medical comorbidity, who were mostly admitted for rehabilitation of cervical, incomplete spinal cord injury/spinal cord disease. Most patients (86.6%) had abnormal electrophysiological studies representing 5.57% of all admissions. A length-dependent polyneuropathy was diagnosed in 0.77% of all admissions (n = 8). The group of patients with spinal cord injury was comparable with the group of patients with spinal cord disease regarding the other baseline data, clinical, and electrophysiological findings.

CONCLUSIONS

Diseases of the peripheral nervous system were similarly found among patients undergoing rehabilitation for either spinal cord injury or spinal cord disease. A length-dependent polyneuropathy was diagnosed in 0.77% of all admissions. Timely diagnosis and proper treatment of the cause of peripheral neuropathies in the lower limbs in these patients may potentially influence rehabilitation protocols and improve patient outcomes.

Identifying disease trajectories with predicate information from a knowledge graph

BACKGROUND

Knowledge graphs can represent the contents of biomedical literature and databases as subject-predicate-object triples, thereby enabling comprehensive analyses that identify e.g. relationships between diseases. Some diseases are often diagnosed in patients in specific temporal sequences, which are referred to as disease trajectories. Here, we determine whether a sequence of two diseases forms a trajectory by leveraging the predicate information from paths between (disease) proteins in a knowledge graph. Furthermore, we determine the added value of directional information of predicates for this task. To do so, we create four feature sets, based on two methods for representing indirect paths, and both with and without directional information of predicates (i.e., which protein is considered subject and which object). The added value of the directional information of predicates is quantified by comparing the classification performance of the feature sets that include or exclude it.

RESULTS

Our method achieved a maximum area under the ROC curve of 89.8% and 74.5% when evaluated with two different reference sets. Use of directional information of predicates significantly improved performance by 6.5 and 2.0 percentage points respectively.

CONCLUSIONS

Our work demonstrates that predicates between proteins can be used to identify disease trajectories. Using the directional information of predicates significantly improved performance over not using this information.

Acellularized spinal cord scaffolds incorporating bpV(pic)/PLGA microspheres promote axonal regeneration and functional recovery after spinal cord injury

Spinal cord injury (SCI) is a traumatic injury to the central nervous system (CNS) with a high rate of disability and a low capability of self-recovery. Phosphatase and tensin homolog (PTEN) inhibition by pharmacological blockade with bisperoxovanadium (pic) (bpV(pic)) has been reported to increase AKT/mTOR activity and induce robust axonal elongation and regeneration. However, the therapeutic effect of bpV(pic) in treating SCI is limited due to the lack of efficient delivery approaches. In this study, a composite scaffold consisting of an acellular spinal cord (ASC) scaffold and incorporated bpV(pic) loaded poly (lactic-co-glycolic acid) (PLGA) microspheres was developed, in order to improve the therapeutic effect of bpV(pic) on SCI. The inhibition of PTEN activity and activation of the mTORC1/AKT pathway, the axonal regeneration and the markers of apoptosis were analyzed via western blot and immunofluorescence in vitro. The bpV(pic)/PLGA/ASC scaffolds showed excellent biocompatibility and promoted the viability of neural stem cells and axonal growth in vitro. Implantation of the composite scaffold into rats with hemi-sectioned SCI resulted in increased axonal regeneration and functional recovery in vivo. Besides, bpV(pic) inhibited the phosphorylation of PTEN and activated the PI3K/mTOR signaling pathway. The successful construction of the composite scaffold improves the therapeutic effect of bpV(pic) on SCI.

MR defecography detects pelvic floor dysfunction in participants with chronic complete spinal cord injury

STUDY DESIGN

A prospective single arm study.

OBJECTIVES

Previously we have demonstrated that magnetic resonance (MR) defecography is feasible in participants with complete spinal cord injury (SCI). The main aim of this study is to evaluate whether MR defecography can provide objective parameters correlating with the clinical manifestations of neurogenic bowel dysfunction (NBD) in participants with SCI.

SETTING

A monocentric study in a comprehensive care university hospital Spinal Cord Injury Center.

METHODS

Previously published MR defecography parameters (anorectal angle (ARA), hiatal descent (M-line) and hiatal width (H-line)) of twenty participants with SCI were now compared to a standardized clinical assessment of NBD. Descriptive statistics, correlations and t-tests for independent samples were calculated.

RESULTS

The significantly higher values for the ARA at rest and M-line at rest in participants with SCI correlated with the clinical assessment of bowel incontinence. Furthermore, in nearly half of the investigated SCI cohort the normally positive difference between ARA, M-line and H-line at rest and during defecation became negative suggesting pelvic floor dyssynergia as a potential mechanism underlying constipation in people with complete SCI. In fact, these participants showed a more severe clinical presentation of NBD according to the total NBD score.

CONCLUSIONS

MR defecography provides objective parameters correlating with clinical signs of NBD, such as constipation and bowel incontinence. Therefore, MR defecography can support pathophysiology-based decision-making with respect to specific therapeutic interventions, which should help to improve the management of NBD.

The protection of acute spinal cord injury by subarachnoid space injection of Danshen in animal models

CONTEXT/OBJECTIVE

Following acute spinal cord injury (ASCI) in rabbits, subarachnoid space injection of Danshen was performed to protect the neurological damage. In this study, we established rabbit models of spinal cord injury using a modified Allen's method.

DESIGN

After the operation introducing the injuries, the rabbits were randomized into two different groups, control group (normal saline, NS) and Danshen, a component extracted from Chinese herb, treatment group. Each rabbit was supplied with either the drug or placebo at 0.3 ml/kg each day through subarachnoid cavity.

SETTING

Rabbit model of acute spinal cord injury were used for the response to Danshen treatment.

PARTICIPANTS

Total 48 Chinese rabbits aged four∼ five months old provided by Experimental Animal Center of Hubei Province were used for this study.

INTERVENTIONS

Danshen drug or placebo was administered via a silicon tube embedded under the spinal dura mater to administer the drugs into subarachnoid cavity.

OUTCOME MEASURES

After the treatment, damage indicators including cell apoptosis, morphological changes and oxidative damages were assessed.

RESULTS

We found out that cell apoptosis was decreased after Danshen injection as determined by downregulation of apoptosis index (AI) by TUNEL analysis as well as propidium iodide (PI) percentage by FACS analysis. In the meanwhile, we observed cells after the treatment have increased numbers of BCL-2 positive cells, this indicated the antiapoptotic gene expression is increased after Danshen treatment. When we check the oxidative damage indicators, we found superoxide dismutase (SOD) was increased and malondiadehyde (MDA) levels were decreased after the treatment.

CONCLUSION

Danshen can protect ASCI through inhibition of oxidative damage in the injured cells and thus reduce the subsequent cell apoptosis in the spinal.

Bisperoxovanadium protects against spinal cord injury by regulating autophagy via activation of ERK1/2 signaling

Background

Spinal cord injury (SCI) is a disease of the central nervous system with few restorative treatments. Autophagy has been regarded as a promising therapeutic target for SCI. The inhibitor of phosphatase and tensin homolog deleted on chromosome ten (PTEN) bisperoxovanadium (bpV[pic]) had been claimed to provide a neuroprotective effect on SCI; but the underlying mechanism is still not fully understood.

Materials and methods

Acute SCI model were generated with SD Rats and were treated with control, acellular spinal cord scaffolds (ASC) obtained from normal rats, bpV(pic), and combined material of ASC and bpV(pic). We used BBB score to assess the motor function of the rats and the motor neurons were stained with Nissl staining. The expressions of the main autophagy markers LC3B, Beclin1 and P62, expressions of apoptosis makers Bax, Bcl2, PARP and Caspase 3 were detected with IF or Western Blot analysis.

Results

The bpV(pic) showed significant improvement in functional recovery by activating autophagy and accompanied by decreased neuronal apoptosis; combined ASC with bpV(pic) enhanced these effects. In addition, after treatment with ERK1/2 inhibitor SCH772984, we revealed that bpV(pic) promotes autophagy and inhibits apoptosis through activating ERK1/2 signaling after SCI.

Conclusion

These results illustrated that the bpV(pic) protects against SCI by regulating autophagy via activation of ERK1/2 signaling.

First-in-Man Intrathecal Application of Neurite Growth-Promoting Anti-Nogo-A Antibodies in Acute Spinal Cord Injury

Background. Neutralization of central nervous system neurite growth inhibitory factors, for example, Nogo-A, is a promising approach to improving recovery following spinal cord injury (SCI). In animal SCI models, intrathecal delivery of anti-Nogo-A antibodies promoted regenerative neurite growth and functional recovery. Objective. This first-in-man study assessed the feasibility, safety, tolerability, pharmacokinetics, and preliminary efficacy of the human anti-Nogo-A antibody ATI355 following intrathecal administration in patients with acute, complete traumatic paraplegia and tetraplegia. Methods. Patients (N = 52) started treatment 4 to 60 days postinjury. Four consecutive dose-escalation cohorts received 5 to 30 mg/2.5 mL/day continuous intrathecal ATI355 infusion over 24 hours to 28 days. Following pharmacokinetic evaluation, 2 further cohorts received a bolus regimen (6 intrathecal injections of 22.5 and 45 mg/3 mL, respectively, over 4 weeks). Results. ATI355 was well tolerated up to 1-year follow-up. All patients experienced ≥1 adverse events (AEs). The 581 reported AEs were mostly mild and to be expected following acute SCI. Fifteen patients reported 16 serious AEs, none related to ATI355; one bacterial meningitis case was considered related to intrathecal administration. ATI355 serum levels showed dose-dependency, and intersubject cerebrospinal fluid levels were highly variable after infusion and bolus injection. In 1 paraplegic patient, motor scores improved by 8 points. In tetraplegic patients, mean total motor scores increased, with 3/19 gaining >10 points, and 1/19 27 points at Week 48. Conversion from complete to incomplete SCI occurred in 7/19 patients with tetraplegia. Conclusions. ATI335 was well tolerated in humans; efficacy trials using intrathecal antibody administration may be considered in acute SCI.

Bacterial load of conditioned pressure ulcers is not a predictor for early flap failure in spinal cord injury

OBJECTIVES

Pressure ulcers impose a major lifetime medical problem to patients with high-grade spinal cord injury (SCI). For patients with stages 3-4 pressure ulcers, plastic surgery is often the only remaining treatment option. Despite considerable flap failure rates of around 30%, only sparse knowledge exists on predictors for flap failure. Hence, identification of predictors for flap failures is needed.

METHODS

We prospectively enrolled 38 SCI patients with stages 3-4 pressure ulcers scheduled for plastic surgery. Preoperative wound swabs, intraoperative tissue samples and postoperative drainage liquids were microbiologically analyzed. In multivariable logistic regression analyses, bacterial loads of deep tissue cultures of intraoperative samples as well as other clinical variables were analyzed with respect to the prediction of flap failures.

RESULTS

The flap failure rate was 27.5%. Bacterial loads of deep tissue cultures were not predictive for flap failure, neither was the colonization with a specific bacterial strain. We observed a considerable fluctuation of microbiological environment from initial swab cultures, intraoperative samples and postoperative drainage fluids. Antibioprophylaxis was sufficient in only 75% of deep tissue cultures and 69% of drainage fluids. Insufficient antibioprophylaxis was associated with a higher flap failure rates (odds ratio 6.3, confidence interval 1.2-41.0).

CONCLUSION

After inpatient wound conditioning, bacterial load analysis of intraoperative wound tissue cultures is ineffective in order to predict flap failure rates in SCI patients with stages 3-4 pressure ulcers after flap surgery. Instead, insufficient antibioprophylaxis might be a factor contributing to flap failure.

Ultrasonographic evaluation of sciatic nerves in patients with spinal cord injury

STUDY DESIGN

Cross-sectional, controlled study.

OBJECTIVE

To evaluate the sciatic nerves of subjects with spinal cord injury (SCI) by using ultrasound (US) imaging and to explore whether US measurements are associated with clinical and electrophysiological findings.

SETTING

National Rehabilitation Center in Ankara, Turkey.

METHODS

Fifteen SCI subjects (12 male (M), 3 female (F)) and 23 (16 M, 7 F) healthy controls were included in the study. After clinical assessment of the subjects, lower limb nerve conduction studies and US imaging of the sciatic nerves were performed. Cross-sectional area (CSA) values of the sciatic nerves were correlated with the clinical and electrophysiologic data.

RESULTS

Mean CSA values were lower in the patient group when compared with the control group (P=0.042). Reduced compound motor action potentials regarding tibial and peroneal nerves were observed in the patient group (P=0.003 and P=0.005, respectively). US measurements did not correlate with the electrophysiological findings. However, sciatic nerve CSA values were positively correlated with body mass index in the control (r=0.534, P<0.05) and patient (r=0.482, P<0.05) groups.

CONCLUSION

Sciatic nerves seem to be smaller in subjects with SCI. Together with our electrophysiological data, this preliminary finding could possibly be attributed to primary axonal loss.