Contusion Injury Research Articles

Cardio-centric hemodynamic management with and without adjuvant ethyl nitrite improves mean arterial pressure in rodents with chronic high-thoracic traumatic spinal cord injury

Objective: Traumatic spinal cord injury (SCI) causes an initial injury followed by a protracted phase of spinal cord tissue hypoxia. This tissue hypoxia contributes to secondary injury, leading to worse motor and cardio-autonomic outcomes in the chronic setting. No neuroprotective agents to mitigate secondary injury have been identified as efficacious in clinical trials. However, we have demonstrated that taking a cardio-centric approach to hemodynamic management following SCI by augmenting cardiac output and mean arterial pressure (MAP) with the b1-adrenoceptor agonist dobutamine (DOB), and further coupling DOB infusion with the inhalation of ethyl nitrite (ENO), an S-nitrosylating agent, is associated with improved spinal cord oxygenation in the acute phase post-SCI. Aim: To determine the influence of a cardio-centric approach to hemodynamic management with adjuvant ENO inhalation following SCI on long term outcomes. We hypothesized that treatment with DOB and ENO in the acute phase following SCI would mitigate secondary injury and improve cardiovascular outcomes in the chronic setting. Methods. A total of 34 male Wistar rats underwent a T3 contusion injury (300 kdyn) and were assigned into 4 treatment groups: control (n=6), ENO (n=6), DOB (n=12), and combined DOB and ENO (n=10). At 11-weeks post-SCI, a locomotor assessment was conducted using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. At 12-weeks post-SCI, rodents were anesthetized with intravenous urethane (2.44±0.50 g/kg) and instrumented with a solid-state pressure transducer in the carotid artery to measure MAP. Results. We observed a higher MAP in both DOB (113.6 ± 11.4 mmHg; p = 0.030) and ENO+DOB (116.7 ± 14.6 mmHg; p=0.013) treated groups when compared with controls (94.65 ± 11.62 mmHg). The MAP of ENO treated animals (91.6 ± 7.3 mmHg; P= 0.97) was not different from controls. No differences in BBB scores were found between DOB (15.17 ± 4.49), ENO+DOB (13.95 ± 3.86), ENO (12.5 ± 2.5) and control (11.8 ± 2.7)(P=0.29). Collectively, these data suggest that DOB treatment, alone or in combination with ENO, improves systemic hemodynamics in the chronic high-thoracic SCI setting US Department of Defense, ICORD Seed Grant, Craig H. Neilsen Foundation This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Evaluation of the Autologous Genetically Enriched Leucoconcentrate on the Lumbar Spinal Cord Morpho-Functional Recovery in a Mini Pig with Thoracic Spine Contusion Injury.

Pathological changes associated with spinal cord injury (SCI) can be observed distant, rostral, or caudal to the epicenter of injury. These remote areas represent important therapeutic targets for post-traumatic spinal cord repair. The present study aimed to investigate the following in relation to SCI: distant changes in the spinal cord, peripheral nerve, and muscles. The changes in the spinal cord, the tibial nerve, and the hind limb muscles were evaluated in control SCI animals and after intravenous infusion of autologous leucoconcentrate enriched with genes encoding neuroprotective factors (VEGF, GDNF, and NCAM), which previously demonstrated a positive effect on post-traumatic restoration. Two months after thoracic contusion in the treated mini pigs, a positive remodeling of the macro- and microglial cells, expression of PSD95 and Chat in the lumbar spinal cord, and preservation of the number and morphological characteristics of the myelinated fibers in the tibial nerve were observed and were aligned with hind limb motor recovery and reduced soleus muscle atrophy. Here, we show the positive effect of autologous genetically enriched leucoconcentrate-producing recombinant neuroprotective factors on targets distant to the primary lesion site in mini pigs with SCI. These findings open new perspectives for the therapy of SCI.

General Anesthesia Blocks Pain-Induced Hemorrhage and Locomotor Deficits After Spinal Cord Injury in Rats.

Research has shown that engaging pain (nociceptive) pathways after spinal cord injury (SCI) aggravates secondary injury and undermines locomotor recovery. This is significant because SCI is commonly accompanied by additional tissue damage (polytrauma) that drives nociceptive activity. Cutting communication with the brain by means of a surgical transection, or pharmacologically transecting the cord by slowly infusing a sodium channel blocker (lidocaine) rostral to a thoracic contusion, blocks pain-induced hemorrhage. These observations suggest that the adverse effect of pain after SCI depends on supraspinal (brain) systems. We hypothesize that inhibiting brain activity using a general anesthetic (e.g., pentobarbital, isoflurane) should have a protective effect. The present study shows that placing rats in an anesthetic state with pentobarbital or isoflurane 24 h after a lower thoracic contusion injury blocks pain-induced intraspinal inflammation and hemorrhage when administered before pain. Pentobarbital also extends protective effects against locomotor deficits produced by noxious stimulation. Inducing anesthesia after noxious stimulation, however, has no effect. Similarly, subanesthetic dosages of pentobarbital were also ineffective at blocking pain-induced hemorrhage. Also examined were the hemodynamic impacts of both pain and anesthetic delivery after SCI. Peripheral pain-input induced an acute increase in systolic blood pressure; isoflurane and pentobarbital prevent this increase, which may contribute to the protective effect of anesthesia. The results suggest that placing patients with SCI in a state akin to a medically induced coma can have a protective effect that blocks the adverse effects of pain.

Cortical stimulation leads to shortened myelin sheaths and increased axonal branching in spared axons after cervical spinal cord injury.

Neural activity and learning lead to myelin sheath plasticity in the intact central nervous system (CNS), but this plasticity has not been well-studied after CNS injury. In the context of spinal cord injury (SCI), demyelination occurs at the lesion site and natural remyelination of surviving axons can take months. To determine if neural activity modulates myelin and axon plasticity in the injured, adult CNS, we electrically stimulated the contralesional motor cortex at 10 Hz to drive neural activity in the corticospinal tract of rats with sub-chronic spinal contusion injuries. We quantified myelin and axonal characteristics by tracing corticospinal axons rostral to and at the lesion epicenter and identifying nodes of Ranvier by immunohistochemistry. Three weeks of daily stimulation induced very short myelin sheaths, axon branching, and thinner axons outside of the lesion zone, where remodeling has not previously been reported. Surprisingly, remodeling was particularly robust rostral to the injury which suggests that electrical stimulation can promote white matter plasticity even in areas not directly demyelinated by the contusion. Stimulation did not alter myelin or axons at the lesion site, which suggests that neuronal activity does not contribute to myelin remodeling near the injury in the sub-chronic period. These data are the first to demonstrate wide-scale remodeling of nodal and myelin structures of a mature, long-tract motor pathway in response to electrical stimulation. This finding suggests that neuromodulation promotes white matter plasticity in intact regions of pathways after injury and raises intriguing questions regarding the interplay between axonal and myelin plasticity.

Post traumatic pneumocephalus, its complications and management outcome: A prospective study in tertiary care center

To study clinical course and complications in patients diagnosed to have post-traumatic pneumocephalus based on: 1. Patterns of associated skull fractures; 2 Findings seen in CT scan which may be risk factors for development of CSFR, meningitis or tension pneumocephalus. To study clinical outcome in patients with PTP This prospective observational study was conducted over a period of 14 months from 15 Nov. 2017 to 15 Jan. 2019 in Goa Medical College, a tertiary care centre for the management of all kind of trauma patients including TBI. The study included all cases of TBI with CT head showing PTP alonwith there radiological findings, clinical course, complications and its management outcome. A total of 102 cases of post-traumatic pneumocephalus were included in the study. Motor vehicle accident was found to be major cause of PTP (79.41%). The most common site of post traumatic PTP was subdural (45.1%). Majority of the patients with PTP had focal PTP underlying the fracture segment (63.73%). Majority of the patients (30) had either isolated fracture frontal sinus (18) or multiple basal (12). CSFR was seen in 13 patients. Majority (74.51%) of patients were treated conservatively. Most of operative interventions were done for associated EDH, SDH, Contusion or diffuse brain injuries. Comminuted depressed fracture frontal sinus is most common fracture associated in patients with massive pneumocephalus and CSFR. All patients with evidence of post traumatic PTP and basal skull fracture must be followed over longer period as delayed onset TP, CSF leak and meningitis didn’t show any specific pattern with initial presentation.The use of prophylactic anticonvulsants should be based on the presence of other indications for it.Patients with PTP can be managed without prophylactic antibiotics which can be reserved then only for those with contaminated injuries.TP, CSF leak and meningitis are life threatening complications of PTP. Early recognition and high index of clinical suspicion and prompt treatment results in improvement of vast majority of patients.

A modified finite element dummy model of Chinese adult male used for train collision simulations

ABSTRACT This work established a modified finite element (FE) dummy model representing the Chinese 50th percentile males through the whole segment scaling method, referring to the Total Human Model for Safety (THUMS-AM50) of European and American 50th percentile males. The head, neck, chest, abdomen, and knee-thigh-hip (KTH) of the modified model were validated, respectively, by the cadaver experimental results. Integrating the dummy models with a four-car marshalling train collision FE model, we analysed the dynamic response in terms of human body posture, head, and neck injuries of the Chinese 50th percentile males and the European and American 50th percentile males during the frontal train collision process. The corresponding simulation results fitted well with the experimental tests, indicating that the established modified model exerted great biological fidelity. Compared with European-American 50th percentile males, the Von-Mises stress, shear stress, maximum principal strain (MPS), and the cumulative strain damage measure CSDM0.15 of the brain in the Chinese 50th percentile males were approximately higher by 22.21%, 19.85%, 36.58%, and 47.55%, respectively. That meant the Chinese males might be at a higher risk of brain contusion and diffuse axonal injury (DAI) during the train collision. Meanwhile, the Chinese 50th percentile males had more severe neck extension, especially the maximum cervical vertebrae Von-Mises stress and neck injury predictor (Nij) were increased by 30.3% and 50%, respectively. The established modified model could provide a more accurate simulation for predicting the Chinese body injury response during the train collision.

Morphofunctional Changes in the Spinal Cord of Rats after Contusion Injury with Local Delivery of Methylprednisolone in Combination with a Copolymer.

We studied the neuroprotective effect of local application of methylprednisolone in combination with a block copolymer after contusion spinal cord injury in rats. Histological analysis of the spinal cord showed that delivery of a complex of methylprednisolone with a block copolymer reduced the volume of white and gray matter lesions. An increase in the amplitude of the evoked response of the gastrocnemius muscle was observed during epidural stimulation of the spinal cord 6 h after the injury. The maximum amplitude of the muscle response was greater in the group with local delivery of the methylprednisolone complex with the polymer 72 h after the injury. The obtained results demonstrate the neuroprotective effect of the local administration of the complex and allow to make positive prognosis for the recovery of the sensorimotor functions in rats.

Safety of baclofen versus tizanidine for older adults with musculoskeletal pain.

Baclofen and tizanidine are both muscle relaxants that carry the risk for neuropsychiatric events in older adults but there is a lack of data directly comparing their safety. This study aimed to investigate the relative risk between these two medications in causing injury and delirium in older adults. This was a retrospective cohort study that was completed in an integrated healthcare system in the United States and included patients aged 65 years or older who started baclofen or tizanidine for the treatment of musculoskeletal pain from January 2016 through December 2018. Outcomes included new incidence of injury (concussion, contusion, dislocation, fall, fracture, or other injuries) and delirium. The cohort was followed from the initiation of therapy until the first occurrence of any of the following events: end of the index drug exposure, end of health plan membership, death, or the study end date of December 31st, 2019. Descriptive statistics were used to compare baseline patient characteristics between baclofen and tizanidine treatment groups. Cox proportional hazards model was used to calculate adjusted hazard ratios (HRs) with 95% confidence intervals. The final study cohort included 12,101 and 6,027 older adults in the baclofen and tizanidine group respectively (mean age 72.2 ± 6.2 years old, 59% female). Older adults newly started on baclofen had a greater risk of injury (HR=1.54, 95% CI=1.21-1.96, P=< 0.001) and delirium (HR=3.33, 95% CI=2.11-5.26, p=<0.001) compared to those started on tizanidine. The results of this study suggest that baclofen is associated with higher incidences of injury and delirium compared to tizanidine when used for the treatment of musculoskeletal pain. Future studies should investigate if these risks are dose-related and include a comparison group not exposed to either drug.

Exercise therapy guides cortical reorganization after midthoracic spinal contusion to enhance control of lower thoracic muscles, supporting functional recovery

Postural control is critical for locomotion, allowing for gait changes, obstacle avoidance and navigation of rough terrain. A major problem after spinal cord injury (SCI) is regaining the control of balance to prevent falls and further injury. While the circuits for locomotor pattern generation reside in the spinal cord, postural control consists of multiple, complex networks that interact at the spinal, brainstem and cortical levels. After complete SCI, cortical reorganization establishes novel control of trunk musculature that is required for weight-supported stepping. In this study, we examined the impact of exercise therapy on cortical reorganization in the more clinically relevant models of both moderate and severe midthoracic contusion injury in the rat. Results demonstrate that both spontaneous recovery and therapy induced recovery of weight-supported stepping utilize cortical reorganization. Moreover, exercise therapy further improves outcome by enhancing cortical control of lower thoracic muscles enabling improvements in interlimb coordination associated with improved balance that increases weight-supported stepping. The outcome of this study suggest that cortical control of posture is key to functional improvement in locomotion. This information can be used to improve the timing and type of therapy after SCI by considering changes along the entire neural axis.

Spatiotemporal microvascular changes following contusive spinal cord injury.

Microvascular integrity is disrupted following spinal cord injury (SCI) by both primary and secondary insults. Changes to neuronal structures are well documented, but little is known about how the capillaries change and recover following injury. Spatiotemporal morphological information is required to explore potential treatments targeting the microvasculature post-SCI to improve functional recovery. Sprague-Dawley rats were given a T10 moderate/severe (200 kDyn) contusion injury and were perfuse-fixed at days 2, 5, 15, and 45 post-injury. Unbiased stereology following immunohistochemistry in four areas (ventral and dorsal grey and white matter) across seven spinal segments (n = 4 for each group) was used to calculate microvessel density, surface area, and areal density. In intact sham spinal cords, average microvessel density across the thoracic spinal cord was: ventral grey matter: 571 ± 45 mm-2, dorsal grey matter: 484 ± 33 mm-2, ventral white matter: 90 ± 8 mm-2, dorsal white matter: 88 ± 7 mm-2. Post-SCI, acute microvascular disruption was evident, particularly at the injury epicentre, and spreading three spinal segments rostrally and caudally. Damage was most severe in grey matter at the injury epicentre (T10) and T11. Reductions in all morphological parameters (95-99% at day 2 post-SCI) implied vessel regression and/or collapse acutely. Transmission electron microscopy (TEM) revealed disturbed aspects of neurovascular unit fine structure at day 2 post-SCI (n = 2 per group) at T10 and T11. TEM demonstrated a more diffuse and disrupted basement membrane and wider intercellular clefts at day 2, suggesting a more permeable blood spinal cord barrier and microvessel remodelling. Some evidence of angiogenesis was seen during recovery from days 2 to 45, indicated by increased vessel density, surface area, and areal density at day 45. These novel results show that the spinal cord microvasculature is highly adaptive following SCI, even at chronic stages and up to three spinal segments from the injury epicentre. Multiple measures of gross and fine capillary structure from acute to chronic time points provide insight into microvascular remodelling post-SCI. We have identified key vascular treatment targets, namely stabilising damaged capillaries and replacing destroyed vessels, which may be used to improve functional outcomes following SCI in the future.

Ferroptosis inhibition protects vascular endothelial cells and maintains integrity of the blood-spinal cord barrier after spinal cord injury.

Maintaining the integrity of the blood-spinal cord barrier is critical for the recovery of spinal cord injury. Ferroptosis contributes to the pathogenesis of spinal cord injury. We hypothesized that ferroptosis is involved in disruption of the blood-spinal cord barrier. In this study, we administered the ferroptosis inhibitor liproxstatin-1 intraperitoneally after contusive spinal cord injury in rats. Liproxstatin-1 improved locomotor recovery and somatosensory evoked potential electrophysiological performance after spinal cord injury. Liproxstatin-1 maintained blood-spinal cord barrier integrity by upregulation of the expression of tight junction protein. Liproxstatin-1 inhibited ferroptosis of endothelial cell after spinal cord injury, as shown by the immunofluorescence of an endothelial cell marker (rat endothelium cell antigen-1, RECA-1) and ferroptosis markers Acyl-CoA synthetase long-chain family member 4 and 15-lipoxygenase. Liproxstatin-1 reduced brain endothelial cell ferroptosis in vitro by upregulating glutathione peroxidase 4 and downregulating Acyl-CoA synthetase long-chain family member 4 and 15-lipoxygenase. Furthermore, inflammatory cell recruitment and astrogliosis were mitigated after liproxstatin-1 treatment. In summary, liproxstatin-1 improved spinal cord injury recovery by inhibiting ferroptosis in endothelial cells and maintaining blood-spinal cord barrier integrity.

Differential effects of NOX2 and NOX4 inhibition after rodent spinal cord injury.

Reactive oxygen species (ROS) are a contributing factor to impaired function and pathology after spinal cord injury (SCI). The NADPH oxidase (NOX) enzyme is a key source of ROS; there are several NOX family members, including NOX2 and NOX4, that may play a role in ROS production after SCI. Previously, we showed that a temporary inhibition of NOX2 by intrathecal administration of gp91ds-tat immediately after injury improved recovery in a mouse SCI model. However, chronic inflammation was not affected by this single acute treatment, and other NOX family members were not assessed. Therefore, we aimed to explore the effect of genetic knockout (KO) of NOX2 or acute inhibition of NOX4 with GKT137831. A moderate SCI contusion injury was performed in 3 month old NOX2 KO and wild-type (WT) mice, who received no treatment or GKT137831/vehicle 30 minutes post-injury. Motor function was assessed using the Basso Mouse Scale (BMS), followed by evaluation of inflammation and oxidative stress markers. NOX2 KO mice, but not GKT137831 treated mice, demonstrated significantly improved BMS scores at 7, 14, and 28 days post injury (DPI) in comparison to WT mice. However, both NOX2 KO and GKT137831 significantly reduced ROS production and oxidative stress markers. Furthermore, a shift in microglial activation toward a more neuroprotective, anti-inflammatory state was observed in KO mice at 7 DPI and a reduction of microglial markers at 28 days. While acute alterations in inflammation were noted with GKT137831 administration, this was not sustained through 28 days. In vitro analysis also showed that while GKT137831 reduced ROS production by microglia, it did not translate to changes in pro-inflammatory marker expression within these cells. These data demonstrate that NOX2 and NOX4 play a role in post-injury ROS, but a single dose of NOX4 inhibitor fails to enhance long-term recovery.

Plication for diaphragm paralysis after paediatric cardiac surgery: a single-centre experience.

Diaphragm paralysis is a well-known complication following surgery for CHDs, which increases morbidity, mortality, and length of hospital stay as well as costs. Herein, we present our experience with diaphragm plication following paralysis of the phrenic nerve encountered after paediatric cardiac surgery. This study retrospectively reviewed the medical records of 23 diaphragm plications in 20 patients who underwent paediatric cardiac surgery between January 2012 and January 2022. The patients were carefully selected based on aetiology and a combination of clinical manifestation and chest imaging characteristics including chest X-ray, ultrasonography, and fluoroscopy. Twenty-three successful plications were performed in 20 patients (15 males and 5 females) out of a total of 1938 operations performed in our centre. Mean age and body weight were 18.2 ± 17.1 months and 8.3 ± 3.7 kg, respectively. The period between the cardiac surgery and diaphragmatic plication was 18.7 ± 15.1 days. The highest incidence of diaphragm paralysis was encountered in systemic to pulmonary artery shunt patients with 7 out of 152 patients (4.6%). Any mortality was not encountered during a mean follow-up period of 4.3 ± 2.6 years. Early results of plication of the diaphragm following phrenic nerve palsy in symptomatic patients who underwent paediatric cardiac surgery are encouraging. Evaluation of the diaphragmatic function should be a routine part of post-operative echocardiography. Diaphragm paralysis may be a consequence of dissection, contusion, stretching, and thermal injury both in terms of hypothermia and hyperthermia.

Adipose-derived Stem Cell Transplantation Enhances Peripheral Nerve Regeneration in a Peroneal Nerve Injury Model in the Rat

Introduction: Despite advances in the treatment of peripheral nerve injury, patients still suffer from incomplete motor recovery. In vivo and in vitro studies demonstrated that adipose derived stem cells (AdSCs) promote peripheral nerve regeneration, but the effect on motor recovery remains unclear. Materials and Methods: According to sample size calculation and randomization 48 rats received either intramuscular, intraneural, combined or vehicle injection of AdSCs following common peroneal nerve contusion injury in narcosis. During the four-week follow-up period, the animals underwent weekly footprint and videometric joint-angle analysis. Finally, the animals underwent isometric force measurement of the tibialis anterior muscle for twitch force, tetanic force, fatigue and electromyography. Results: During the four weeks of follow-up all groups regained full recovery of their gait, marked by Inserra’s peroneal functional index analysing toespread and the joint angle analysis. In Isometric force measurement using twitch force, tetanic force and fatique, intramuscular transplantation was superior to intraneural or combined transplantation. Muscle trophy was highest in intraneural injection, measured by wet weight of the tibialis anterior muscle. Conclusion: Our preliminary data indicate a superior force regeneration with intramuscular AdSC transplantation compared to intraneural, combined or vehicle transplantation. Further exploratory data suggest that transplantation of extracellular vesicles presented with even higher force regeneration.

Resveratrol suppresses neuroinflammation to alleviate mechanical allodynia by inhibiting Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway in a rat model of spinal cord injury.

Neuropathic pain (NP) is one of intractable complications of spinal cord injury (SCI) and lacks effective treatment. Resveratrol (Res) has been shown to possess potent anti-inflammatory and anti-nociceptive effects. In this study, we investigated the analgesic effect of Res and its underlying mechanism in a rat model of SCI. The rat thoracic (T10) spinal cord contusion injury model was established, and mechanical thresholds were evaluated during an observation period of 21 days. Intrathecal administration with Res (300 μg/10 μl) was performed once a day for 7 days after the operation. On postoperative day 7, the expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA) and Real-time quantitative PCR (RT-qPCR), the expression of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway was determined by western blot and RT-qPCR, and the co-labeled phospho-STAT3 (p-STAT3) with neuronal nuclear antigen (NeuN), glial fibrillary acidic protein (GFAP), and ionized calcium-binding adapter molecule 1 (Iba-1) were explored by double immunofluorescence staining in the lumbar spinal dorsal horns. The temporal changes of p-STAT3 were investigated by western blot on the 1st, 3rd, 7th, 14th, and 21st days after the operation. Intrathecal administration with Res for 7 successive days alleviated mechanical allodynia of rats during the observation period. Meanwhile, treatment with Res suppressed the production of pro-inflammatory factors TNF-α, IL-1β and IL-6, and inhibited the expressions of phospho-JAK2 and p-STAT3 in the lumbar spinal dorsal horns on postoperative day 7. Additionally, the protein expression of p-STAT3 was significantly increased on the 1st day following the operation and remained elevated during the next 21 days, immunofluorescence suggested that the up-regulated p-STAT3 was co-located with glial cells and neurons. Our current results indicated that intrathecal administration with Res effectively alleviated mechanical allodynia after SCI in rats, and its analgesic mechanism might be to suppress neuroinflammation by partly inhibiting JAK2/STAT3 signaling pathway.

Acute Transcriptomic and Epigenetic Alterations at T12 After Rat T10 Spinal Cord Contusive Injury.

Spinal cord injury is a severely debilitating condition affecting a significant population in the USA. Spinal cord injury patients often have increased risk of developing persistent neuropathic pain and other neurodegenerative conditions beyond the primary lesion center later in their life. The molecular mechanism conferring to the "latent" damages at distal tissues, however, remains elusive. Here, we studied molecular changes conferring abnormal functionality at distal spinal cord (T12) beyond the lesion center (T10) by combining next-generation sequencing (RNA- and bisulfite sequencing), super-resolution microscopy, and immunofluorescence staining at 7days post injury. We observed significant transcriptomic changes primarily enriched in neuroinflammation and synaptogenesis associated pathways. Transcription factors (TFs) that regulate neurogenesis and neuron plasticity, including Egr1, Klf4, and Myc, are significantly upregulated. Along with global changes in chromatin arrangements and DNA methylation, including 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), bisulfite sequencing further reveals the involvement of DNA methylation changes in regulating cytokine, growth factor, and ion channel expression. Collectively, our results pave the way towards understanding transcriptomic and epigenomic mechanism in conferring long-term disease risks at distal tissues away from the primary lesion center and shed light on potential molecular targets that govern the regulatory mechanism at distal spinal cord tissues.

Relationship Between Bone Bruise Volume and Patient Outcomes After ACL Reconstruction.

Subchondral bone injuries, or bone bruises, are commonly observed on magnetic resonance imaging (MRI) after anterior cruciate ligament (ACL) injury. The current relationship between bone bruise volume and postsurgical outcomes remains poorly understood. To examine the influence of bone bruise volume on self-reported and objective functional outcomes at the time of return to play and 2 years following ACL reconstruction. Cohort study; Level of evidence, 3. Clinical, surgical, and demographic data were obtained for a sample of convenience utilizing a single-surgeon ACL database (n = 1396). For 60 participants, femoral and tibial bone bruise volumes were estimated from preoperative MRI. Data obtained at the time of return to play included International Knee Documentation Committee (IKDC-2000) score, ACL-Return to Sport after Injury (ACL-RSI) score, and performance on an objective functional performance battery. Two-year follow-up data included graft reinjury rate, level of return to sport/activity, and self-reported knee function using the Single Assessment Numeric Evaluation (SANE). The forward stepwise linear regression was used to determine the relationship between bone bruise volume and patient function. The distribution of bone bruise injuries was as follows: lateral femoral condyle (76.7%), lateral tibial plateau (88.3%), medial femoral condyle (21.7%), and medial tibial plateau (26.7%). Mean total bone bruise volume of all compartments was 7065.7 ± 6226.6 mm3. At the 2-year follow up, there were no significant associations between total bone bruise volume and time of return to play (P = .832), IKDC-2000 score (P = .200), ACL-RSI score (P = .370), or SANE score (P = .179). The lateral tibial plateau was the most frequent site to sustain bone bruise injury. Preoperative bone bruise volume was not associated with delayed time to return to sport or self-reported outcomes at time of return to play or at 2 years postoperatively. NCT03704376 (ClinicalTrials.gov identifier).

A case report: extracorporeal membrane oxygenation for multitrauma patient with pneumorrhagia

BackgroundExtracorporeal membrane oxygenation (ECMO) can be used as salvage therapy for multitrauma patients with acute respiratory distress syndrome (ARDS) when conventional treatment fails to maintain oxygenation. However, controversy exists between ECMO application and the risk of bleeding due to systemic anticoagulation during the treatment. Non-heparin introduction seems to be a possible solution for this dilemma, owing to technical improvements in the device and management methods of ECMO.Case presentationA 58-year-old woman suffered from blunt thoracic, pelvic, and right lower limb fractures due to a falling accident, which resulted in acute respiratory distress syndrome (ARDS). Although the patient received intubation and mechanical ventilation (MV), respiratory failure was not alleviated. Venous-venous (V-V) ECMO was used as a salvage therapy. With the support of V-V ECMO, we safely cleared blood clots in the bronchus and avoided secondary lung injury caused by pressure trauma and oxygen poisoning of the MV. We introduced heparin-free ECMO management as a solution to reduce the risk of bleeding associated with pulmonary contusion and other organ injuries. To prevent thrombosis, we set the blood rate of ECMO to 4.0 L/min, which is much higher than the usual parameter. During ECMO, coagulation factors, such as prothrombin time, activated partial thromboplastin time, and D-dimer, were examined. ECMO was maintained for 5 days without any complications; MV was stopped on the 13th day, extubated on the 24th day, and discharged from ICU on the 28th day.ConclusionECMO with non-heparin could be an optimal treatment for multitrauma patients with ARDS when traditional treatment cannot sustain oxygenation. High blood flow rate could prevent thrombosis through ongoing ECMO therapy without systemic anticoagulation. In addition, monitoring D-dimer value change (Δ D-dimer) may be better than D-dimer value in predicting clot formation in the membrane oxygenator.

AAV Vector Mediated Delivery of NG2 Function Neutralizing Antibody and Neurotrophin NT-3 Improves Synaptic Transmission, Locomotion, and Urinary Tract Function after Spinal Cord Contusion Injury in Adult Rats.

NG2 is a structurally unique transmembrane chondroitin sulfate proteoglycan (CSPG). Its role in damaged spinal cord is dual. NG2 is considered one of key inhibitory factors restricting axonal growth following spinal injury. Additionally, we have recently detected its novel function as a blocker of axonal conduction. Some studies, however, indicate the importance of NG2 presence in the formation of synaptic contacts. We hypothesized that the optimal treatment would be neutralization of inhibitory functions of NG2 without its physical removal. Acute intraspinal injections of anti-NG2 monoclonal antibodies reportedly prevented an acute block of axonal conduction by exogenous NG2. For prolonged delivery of NG2 function neutralizing antibody, we have developed a novel gene therapy: adeno-associated vector (AAV) construct expressing recombinant single-chain variable fragment anti-NG2 antibody (AAV-NG2Ab). We examined effects of AAV-NG2Ab alone or in combination with neurotrophin NT-3 in adult female rats with thoracic T10 contusion injuries. A battery of behavioral tests was used to evaluate locomotor function. In vivo single-cell electrophysiology was used to evaluate synaptic transmission. Lower urinary tract function was assessed during the survival period using metabolic chambers. Terminal cystometry, with acquisition of external urethral sphincter activity and bladder pressure, was used to evaluate bladder function. Both the AAV-NG2Ab and AAV-NG2Ab combined with AAV-NT3 treatment groups demonstrated significant improvements in transmission, locomotion, and bladder function compared with the control (AAV-GFP) group. These functional improvements associated with improved remyelination and plasticity of 5-HT fibers. The best results were observed in the group that received combinational AAV-NG2Ab+AAV-NT3 treatment.SIGNIFICANCE STATEMENT We recently demonstrated beneficial, but transient, effects of neutralization of the NG2 proteoglycan using monoclonal antibodies delivered intrathecally via osmotic mini-pumps after spinal cord injury. Currently, we have developed a novel gene therapy tool for prolonged and clinically relevant delivery of a recombinant single-chain variable fragment anti-NG2 antibody: AAV-rh10 serotype expressing scFv-NG2 (AAV-NG2Ab). Here, we examined effects of AAV-NG2Ab combined with transgene delivery of Neurotrophin-3 (AAV-NT3) in adult rats with thoracic contusion injuries. The AAV-NG2Ab and AAV-NG2Ab+AAV-NT3 treatment groups demonstrated significant improvements of locomotor function and lower urinary tract function. Beneficial effects of this novel gene therapy on locomotion and bladder function associated with improved transmission to motoneurons and plasticity of axons in damaged spinal cord.

Ultrasound-Based Three-Dimensional Microangiography for Repeated Noninvasive Imaging of Neovascularization

Neovascularization plays an essential part in the progression of several diseases as well as recovery processes such as angiogenesis-guided neurogenesis after a spinal cord injury. To visualize and quantify neovascularization in an experimental setup, it is desirable to apply a noninvasive, repeatable, and harmless technique. Here, we apply a newly developed ultrasound-based technique to construct angiographies and quantify neovascularization in the regenerating spinal cord of a regeneration competent animal model, the Mexican axolotl. We measured vessel volume fraction prior to the induction of contusion and transection spinal cord injury and repeated this measurement directly after injury and at 3, 6, 12, and 63 days after injury. Although neither of the injury types resulted in statistically significant differences in vessel volume fraction relative to sham-operated animals, there was a statistically significant increase in neovascularization over time in all groups. Additionally, vessel volume fraction at the final time point (63 days after injury) was quantified with micro-CT imaging after vascular perfusion with a contrast agent, confirming no statistically significant difference in neovascularization between injury types. Ex vivo vessel volume fraction measured by micro-CT was significantly different from the in vivo ultrasound-based measurement at the same time point. This is likely a result of incomplete vascular perfusion with the contrast agent before micro-CT imaging, which was supported by subsequent histological evaluation. In summary, the results suggest that the ultrasound-based angiographic procedure, we demonstrate here, is applicable to visualize and quantify neovascularization in a noninvasive and harmless fashion in longitudinal experiments circumventing the limitations of contrast agent-dependent techniques.