Updated Review: The Steroid Controversy for Management of Spinal Cord Injury

Combinatorial therapies for spinal cord injury repair

Spinal cord injuries have profound detrimental effects on individuals, regardless of whether they are caused by trauma or non-traumatic events. The compromised regeneration of the spinal cord is primarily attributed to damaged neurons, inhibitory molecules, dysfunctional immune response, and glial scarring. Unfortunately, currently, there are no effective treatments available that can fully repair the spinal cord and improve functional outcomes. Nevertheless, numerous pre-clinical approaches have been studied for spinal cord injury recovery, including using biomaterials, cells, drugs, or technological-based strategies. Combinatorial treatments, which target various aspects of spinal cord injury pathophysiology, have been extensively tested in the last decade. These approaches aim to synergistically enhance repair processes by addressing various obstacles faced during spinal cord regeneration. Thus, this review intends to provide scientists and clinicians with an overview of pre-clinical combinatorial approaches that have been developed toward the solution of spinal cord regeneration as well as update the current knowledge about spinal cord injury pathophysiology with an emphasis on the current clinical management.

Mechanisms of nitric oxide in spinal cord injury

Spinal cord injury (SCI) is a primary lesion of the spinal cord that results from external forces or diseases, accompanied by a cascade of secondary events. Nitric oxide, an endogenous gas that functions as a signaling molecule in the human body, plays a crucial role in vasodilation of smooth muscles, regulation of blood flow and pressure, and inflammatory response. This article provides a comprehensive overview of the involvement of nitric oxide in SCI and highlights recent advances in basic research on pharmacological agents that inhibit nitric oxide elevation after SCI, offering valuable insights for future therapeutic interventions targeting SCI.

Traumatic Cervical Facet Fractures and Dislocations

Cervical facet injuries, though less common than other spinal injuries, represent a subset of subaxial cervical spine injuries and can present significant challenges in terms of diagnosis, management, and outcomes. A major concern with cervical facet fracture is identifying instability patterns that may necessitate surgical stabilization. Particularly in cases of cervical facet fracture dislocations, there remains controversy regarding requirements for closed reduction, timing, surgical approach, need for preoperative MRI, and method of fixation. This review article aims to provide a thorough understanding of the etiology, clinical presentation, diagnostic techniques, treatment options, and prognostic factors associated with cervical facet fractures.

Impact of commonly administered drugs on the progression of spinal cord injury: a systematic review

BACKGROUND

Complications arising from acute traumatic spinal cord injury (SCI) are routinely managed by various pharmacological interventions. Despite decades of clinical application, the potential impact on neurological recovery has been largely overlooked. This study aims to highlight commonly administered drugs with potential disease-modifying effects.

METHODS

This systematic literature review included studies referenced in PubMed, Scopus and Web of Science from inception to March 31st, 2021, which assess disease-modifying properties on neurological and/or functional recovery of drugs routinely administered following spinal cord injury. Drug effects were classified as positive, negative, mixed, no effect, or not (statistically) reported. Risk of bias was assessed separately for animal, randomized clinical trials, and observational human studies.

RESULTS

We analyzed 394 studies conducting 486 experiments that evaluated 144 unique or combinations of drugs. 195 of the 464 experiments conducted on animals (42%) and one study in humans demonstrate positive disease-modifying properties on neurological and/or functional outcomes. Methylprednisolone, melatonin, estradiol, and atorvastatin are the most common drugs associated with positive effects. Two studies on morphine and ethanol report negative effects on recovery.

CONCLUSION

Despite a large heterogeneity observed in study protocols, research from bed to bench and back to bedside provides an alternative approach to identify new candidate drugs in the context of SCI. Future research in human populations is warranted to determine if introducing drugs like melatonin, estradiol, or atorvastatin would contribute to enhancing neurological outcomes after acute SCI.

A confounding pediatric spinal cord injury: Anterior, central, or both?

Pediatric spinal cord injury (SCI) most commonly affects the cervical region. Central cord syndrome most often occurs in the lower cervical injury due to hyperextension injury, while anterior cord syndrome is primarily due to vascular infarction after hyperextension injury. An unusual case of a pediatric patient who physically presented with central cord syndrome but radiologically had evidence of anterior spinal artery syndrome is described. A two-year-old male presented after a fall from three feet with flaccid upper extremities and dysesthesias but maintained functional strength in bilateral lower extremities. Although his clinical presentation was that of central cord syndrome, he was found to have an anterior spinal artery infarct spanning from C2-T3 with a ligamentous injury at C3 and an incidental finding of Chiari I malformation on MRI. Given the negative evaluation for a cardiac or hematologic source of embolus and normal angiography, it was theorized that compression of vertebral arteries by previously undiagnosed Chiari I malformation in the setting of trauma could have made the patient more vulnerable to this complication. During inpatient rehabilitation, he regained scapular movement and shoulder flexion. However, he regained distal movement in supination, wrist extension, and finger flexion instead of the more usual proximal-to-distal motor recovery observed in SCI. While he had a relative sparing of strength in his legs, he had impaired proprioception and balance, leading to gait impairment. This case highlights the complexity of pediatric cervical SCI diagnosis and prognostication. While classic SCI subtypes are well described, many pediatric and adult patients will present and recover in unexpected ways. All with SCI should be evaluated thoroughly for common etiologies and transitioned to rehabilitation therapies to assist in recovery.

Biochanin A attenuates spinal cord injury in rats during early stages by inhibiting oxidative stress and inflammasome activation

JOURNAL/nrgr/04.03/01300535-202409000-00038/figure1/v/2024-01-16T170235Z/r/image-tiff Previous studies have shown that Biochanin A, a flavonoid compound with estrogenic effects, can serve as a neuroprotective agent in the context of cerebral ischemia/reperfusion injury; however, its effect on spinal cord injury is still unclear. In this study, a rat model of spinal cord injury was established using the heavy object impact method, and the rats were then treated with Biochanin A (40 mg/kg) via intraperitoneal injection for 14 consecutive days. The results showed that Biochanin A effectively alleviated spinal cord neuronal injury and spinal cord tissue injury, reduced inflammation and oxidative stress in spinal cord neurons, and reduced apoptosis and pyroptosis. In addition, Biochanin A inhibited the expression of inflammasome-related proteins (ASC, NLRP3, and GSDMD) and the Toll-like receptor 4/nuclear factor-κB pathway, activated the Nrf2/heme oxygenase 1 signaling pathway, and increased the expression of the autophagy markers LC3 II, Beclin-1, and P62. Moreover, the therapeutic effects of Biochanin A on early post-spinal cord injury were similar to those of methylprednisolone. These findings suggest that Biochanin A protected neurons in the injured spinal cord through the Toll-like receptor 4/nuclear factor κB and Nrf2/heme oxygenase 1 signaling pathways. These findings suggest that Biochanin A can alleviate post-spinal cord injury at an early stage.

STM2457 Inhibits METTL3-Mediated m6A Modification of miR-30c to Alleviate Spinal Cord Injury by Inducing the ATG5-Mediated Autophagy

OBJECTIVE

The study aimed to investigate the role of N6-methyladenosine (m6A) modification in spinal cord injury (SCI) and its underlying mechanism, focusing on the interplay between m6A methyltransferase-like 3 (METTL3), miR-30c, and autophagy-related proteins.

METHODS

An SCI model was established in rats, and changes in autophagy-related proteins, m6A methylation levels, and miR-30c levels were analyzed. Hydrogen peroxide (H2O2)-stimulated spinal cord neuron cells (SCNCs) were used to assess the impact of METTL3 overexpression. The effects of STM2457, an antagonist of METTL3, were evaluated on cell viability, apoptosis, and autophagy markers in H2O2-stimulated SCNCs.

RESULTS

In the SCI model, decreased levels of autophagy markers and increased m6A methylation, miR-30c levels, and METTL3 were observed. Overexpression of METTL3 in SCNCs led to reduced cell viability, increased apoptosis, and suppressed autophagy. Conversely, co-overexpression of autophagy-related protein 5 (ATG5) or miR-30c inhibition reversed these effects. Knocking out METTL3 yielded opposite results. STM2457 treatment improved cell viability, reduced apoptosis, and upregulated autophagy markers in SCNCs, which also enhanced functional recovery in rats as measured by the Basso-Beattie-Bresnahan score and inclined plate test.

CONCLUSION

STM2457 alleviated SCI by suppressing METTL3-mediated m6A modification of miR-30c, which in turn induces ATG5-mediated autophagy. This study provides insights into the role of m6A modification in SCI and suggests a potential therapeutic approach through targeting METTL3.

A comprehensive and systematic review of the potential neuroprotective effect of quercetin in rat models of spinal cord injury

CONTEXT

Spinal cord injury (SCI) is a potentially fatal neurological disease with severe complications and a high disability rate. An increasing number of animal experimental studies support the therapeutic effect of quercetin, which is a natural anti-inflammatory and antioxidant bioflavonoid.

OBJECTIVE

This paper reviewed the therapeutic effect of quercetin on a rat SCI model and summarized the relevant mechanistic research.

DATA SOURCES

PubMed, EMBASE, Web of Science, Science Direct, WanFang Data, SinoMed databases, the China National Knowledge Infrastructure, and the Vip Journal Integration Platform were searched from their inception to April 2023 for animal experiments applying quercetin to treat SCI.

STUDY SELECTION

Based on the PICOS criteria, a total of 18 eligible studies were included, of which 14 were high quality.

RESULTS

In this study, there was a gradual increase in effect based on the Basso, Beattie, and Bresnahan (BBB) score after three days (p < 0.0001). Furthermore, gender differences also appeared in the efficacy of quercetin; males performed better than females (p = 0.008). Quercetin was also associated with improved inclined plane test score (p = 0.008). In terms of biochemical indicators, meta-analysis showed that MDA (p < 0.0001) and MPO (p = 0.0002) were significantly reduced after quercetin administration compared with the control group, and SOD levels were increased (p = 0.004). Mechanistically, quercetin facilitates the inhibition of oxidative stress, inflammation, autophagy and apoptosis that occur after SCI.

CONCLUSIONS

Generally, this systematic review suggests that quercetin has a neuroprotective effect on SCI.

Management of traumatic spinal cord injury: A current concepts review of contemporary and future treatment

Spinal Cord Injury (SCI) is a condition leading to inflammation, edema, and dysfunction of the spinal cord, most commonly due to trauma, tumor, infection, or vascular disturbance. Symptoms include sensory and motor loss starting at the level of injury; the extent of damage depends on injury severity as detailed in the ASIA score. In the acute setting, maintaining mean arterial pressure (MAP) higher than 85 mmHg for up to 7 days following injury is preferred; although caution must be exercised when using vasopressors such as phenylephrine due to serious side effects such as pulmonary edema and death. Decompression surgery (DS) may theoretically relieve edema and reduce intraspinal pressure, although timing of surgery remains a matter of debate. Methylprednisolone (MP) is currently used due to its ability to reduce inflammation but more recent studies question its clinical benefits, especially with inconsistency in recommending it nationally and internationally. The choice of MP is further complicated by conflicting evidence for optimal timing to initiate treatment, and by the reported observation that higher doses are correlated with increased risk of complications. Thyrotropin-releasing hormone may be beneficial in less severe injuries. Finally, this review discusses many options currently being researched and have shown promising pre-clinical results.

Spinal subdural haemorrhage secondary to strenuous exercise and warfarin, complicated by acute ischaemic stroke

Spinal subdural haemorrhage or haematoma (SSDH) is a rare condition that is often overlooked and missed on initial presentation due to its non-specific features that may mimic other more common pathologies. It is associated with high morbidity and mortality rates, with few evidence-based management principles, particularly during the subacute stages of recovery. In this report, we detail a case of SSDH associated with exercise and anticoagulation therapy, which was complicated by acute ischaemic stroke. SSDH should be suspected in cases of acute back pain without a clear alternative cause, particularly in coagulopathic individuals. Following treatment, early recommencement of anticoagulation therapy may be justified in certain cases where indicated, after careful consideration of the affected individual's risk profile.

Benefits of Early Surgical Treatment for Patients with Multilevel Cervical Canal Stenosis of Acute Traumatic Central Cord Syndrome

INTRODUCTION

Currently, there exists considerable debate surrounding the optimal treatment approaches for different subtypes of patients with spinal cord injury (SCI). The purpose of this study was to conduct a comparative analysis of the benefits associated with conservative treatment and treatments with different surgical periods for patients diagnosed with acute traumatic central cord syndrome (ATCCS) and multilevel cervical canal stenosis (CCS).

METHODS

A retrospective cohort study was conducted, and 93 patients who met inclusion and exclusion criteria in our hospital between 2015 and 2020 were followed for a minimum duration of 2 years. Among them, 30 patients (Group A) received conservative treatment, 18 patients (Group B) received early surgery (≤7 days), and 45 patients (Group C) received late surgery (>7 days). The American Spinal Injury Association (ASIA) grade, Japanese Orthopedic Association (JOA) score, and recovery rate (RR) were evaluated. Multivariate linear regression was used to analyze prognostic determinants. Cost-utility analysis was performed based on the EQ-5D scale.

RESULTS

The ASIA grade, JOA score, and RR of all three groups improved compared with the previous evaluation (P < 0.05). During follow-up, the ASIA grade, JOA score, and RR of Group B were all better than for Group A and Group C (P < 0.05), while there was no significant difference between Group A and C (P > 0.05). The EQ-5D scale in Group B was optimal at the last follow-up. The incremental cost-utility ratio (ICUR) of Group A was the lowest, while that of Group B compared to Group A was less than the threshold of patients' willingness to pay. Age, initial ASIA grade, and treatment types significantly affected the outcomes.

CONCLUSIONS

Both conservative and surgical treatments yield good results. Compared with patients who received conservative treatment and late surgery, patients who received early surgery had better clinical function and living quality. Despite the higher cost, early surgery is cost-effective when compared to conservative treatment. Younger age, initial better ASIA grade, and earlier surgery were associated with better prognosis.

Improvement of spinal cord injury symptoms by targeting the Bax/Bcl2 pathway and modulating TNF-α/IL-10 using Platelet-Rich Plasma exosomes loaded with dexamethasone

Spinal cord injury (SCI) is a debilitating condition that results in impaired sensory and motor function due to the limited self-regenerative ability of the spinal cord. To address this issue, combination therapy has been proposed as an effective treatment strategy for SCI regeneration. In this study, Platelet-Rich Plasma (PRP)-derived exosomes loaded with dexamethasone were utilized in a mouse model of SCI compression. PRP-derived exosomes loaded with dexamethasone (Dex) were prepared using ultracentrifugation and sonication methods and were administered to the mice via intravenous injection. Following a four-week duration, behavioral assessments were administered to assess functional recuperation, and diverse metrics encompassing the expression of genes associated with apoptosis and antiapoptosis, serum cytokine concentrations and tissue sampling were subjected to thorough examination. The results of this study demonstrated that mice treated with PRP-derived exosomes loaded with Dex (ExoDex) exhibited altered levels of TNF-α and IL-10, along with decreased Bax and increased Bcl2 expression in comparison to the model group. Furthermore, intravenously injected ExoDex reduced the size of the lesion site, lymphocyte infiltration, vacuolation, cavity size and tissue disorganization while also improving locomotor recovery. We propose that the utilization of exosome-loaded Dex therapy holds potential as a promising and clinically relevant approach for injured spinal cord repair. However, further extensive research is warranted in this domain to validate and substantiate the outcomes presented in this study.

Challenges in Translating Regenerative Therapies for Spinal Cord Injury

Regenerating the injured spinal cord is a substantial challenge with many obstacles that need to be overcome to achieve robust functional benefits. This abundance of hurdles can partly explain the limited success when applying regenerative intervention treatments in animal models and/or people. In this article, we elaborate on a few of these obstacles, starting with the applicability of animal models and how they compare to the clinical setting. We then discuss the requirement for combinatorial interventions and the associated problems in experimental design, including the addition of rehabilitative training. The article expands on differences in lesion sizes and locations between humans and common animal models, and how this difference can determine the success or failure of an intervention. An additional and frequently overlooked problem in the translation of interventions that applies beyond the field of neuroregeneration is the reporting bias and the lack of transparency in reporting findings. New data mandates are tackling this problem and will eventually result in a more balanced view of the field. Finally, we will discuss strategies to negotiate the challenging course of successful translation to facilitate successful translation of regeneration promoting interventions.

Mesenchymal Stem Cell Transplantation: Neuroprotection and Nerve Regeneration After Spinal Cord Injury

Spinal Cord Injury (SCI), with its morbidity characteristics of high disability rate and high mortality rate, is a disease that is highly destructive to both the physiology and psychology of the patient, and for which there is still a lack of effective treatment. Following spinal cord injury, a cascade of secondary injury reactions known as ischemia, peripheral inflammatory cell infiltration, oxidative stress, etc. create a microenvironment that is unfavorable to neural recovery and ultimately results in apoptosis and necrosis of neurons and glial cells. Mesenchymal stem cell (MSC) transplantation has emerged as a more promising therapeutic options in recent years. MSC can promote spinal cord injury repair through a variety of mechanisms, including immunomodulation, neuroprotection, and nerve regeneration, giving patients with spinal cord injury hope. In this paper, it is discussed the neuroprotection and nerve regeneration components of MSCs' therapeutic method for treating spinal cord injuries.

Pre-Clinical Assessment of Roflumilast Therapy in a Thoracic Model of Spinal Cord Injury

The failure of axons to regenerate after a spinal cord injury (SCI) remains one of the greatest challenges in neuroscience. The initial mechanical trauma is followed by a secondary injury cascade, creating a hostile microenvironment, which not only is not permissive to regeneration but also leads to further damage. One of the most promising approaches for promoting axonal regeneration is to maintain the levels of cyclic adenosine monophosphate (cAMP), specifically by a phosphodiesterase-4 (PDE4) inhibitor expressed in neural tissues. Therefore, in our study, we evaluated the therapeutic effect of an FDA-approved PDE4 inhibitor, Roflumilast (Rof), in a thoracic contusion rat model. Results indicate that the treatment was effective in promoting functional recovery. Rof-treated animals showed improvements in both gross and fine motor function. Eight weeks post-injury, the animals significantly recovered by achieving occasional weight-supported plantar steps. Histological assessment revealed a significant decrease in cavity size, less reactive microglia, as well as higher axonal regeneration in treated animals. Molecular analysis revealed that IL-10 and IL-13 levels, as well as VEGF, were increased in the serum of Rof-treated animals. Overall, Roflumilast promotes functional recovery and supports neuroregeneration in a severe thoracic contusion injury model and may be important in SCI treatment.

Guidelines for management of pediatric acute hyperextension spinal cord injury

Pediatric acute hyperextension spinal cord injury (SCI) named as PAHSCI by us, is a special type of thoracolumbar SCI without radiographic abnormality and highly related to back-bend in dance training, which has been increasingly reported. At present, it has become the leading cause of SCI in children, and brings a heavy social and economic burden. Both domestic and foreign academic institutions and dance education organizations lack a correct understanding of PAHSCI and relevant standards, specifications or guidelines. In order to provide standardized guidance, the expert team formulated this guideline based on the principles of science and practicability, starting from the diagnosis, differential diagnosis, etiology, admission evaluation, treatment, complications and prevention. This guideline puts forward 23 recommendations for 14 related issues.

Application of platelet-rich plasma in spinal surgery

With the aging of the population and changes in lifestyle, the incidence of spine-related diseases is increasing, which has become a major global public health problem; this results in a huge economic burden on the family and society. Spinal diseases and complications can lead to loss of motor, sensory, and autonomic functions. Therefore, it is necessary to identify effective treatment strategies. Currently, the treatment of spine-related diseases includes conservative, surgical, and minimally invasive interventional therapies. However, these treatment methods have several drawbacks such as drug tolerance and dependence, adjacent spondylosis, secondary surgery, infection, nerve injury, dural rupture, nonunion, and pseudoarthrosis. Further, it is more challenging to promote the regeneration of the interstitial disc and restore its biomechanical properties. Therefore, clinicians urgently need to identify methods that can limit disease progression or cure diseases at the etiological level. Platelet-rich plasma (PRP), a platelet-rich form of plasma extracted from venous blood, is a blood-derived product. Alpha granules contain a large number of cytokines, such as platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor, platelet factor 4 (PF-4), insulin-like growth factor-1 (IGF-1), and transforming growth factor-β (TGF-β). These growth factors allow stem cell proliferation and angiogenesis, promote bone regeneration, improve the local microenvironment, and enhance tissue regeneration capacity and functional recovery. This review describes the application of PRP in the treatment of spine-related diseases and discusses the clinical application of PRP in spinal surgery.

Secondary damage management of acute traumatic spinal cord injury in low and middle-income countries: A survey on a global scale (Part III)

•In LMICs, several factor may affect the applicability of guidelines for secondary damage control of spinal cord injury.•In LMICs, the use of steroids for spinal cord injury is heterogeneous and admissions to an intensive care units are limited.•The delays for surgical decompression of spinal cord injury can be significan and vary across income and geographic region.•Transfer times seem to be the most common reason for surgical delay in all income and geographic regions.•Costs for surgery for spinal trauma may be a significant barrier to guideline adherence, especially in low-resource settings.

Traumatic Nervous System Injury

Mechanisms of traumatic nervous system injury to a degree are similar, but differences exist in etiology, pathophysiology, and treatment of brain, spinal cord, and peripheral nerve injury. The most common clinical abnormalities seen in the horse are abnormal level of consciousness, abnormal behavior, seizures, cranial nerve deficits, vestibular disease, tetra- and paraparesis or paraplegia, cauda equina syndrome, specific gait deficits, and muscle atrophy. Treatments are directed toward reducing inflammation and swelling, halting secondary injury, and promoting mechanisms of neuroregeneration and plasticity. Prognosis depends on the severity of primary injury and the neuroanatomic location and extent of nervous tissue damage.

Effects of astrocytes and microglia on neuroinflammation after spinal cord injury and related immunomodulatory strategies

Spinal cord injury (SCI) is a catastrophic event which is still without adequate therapies. Neuroinflammation is the main pathogenesis of secondary damage post-SCI, leading to tissue loss and neurological dysfunction. Previous studies have shown that microglia and astrocytes are the major immune cells in the central nervous system (CNS) and play a crucial role in modulating neuroinflammatory responses. In this study, we mainly review the effects of neuroinflammation in SCI, focusing on the contributions of microglia and astrocytes and their cross-talk. Furthermore, we will also discuss therapeutic strategies on how to regulate their immunophenotype to suppress robust inflammation and facilitate injury prognosis.

Ac-SDKP peptide improves functional recovery following spinal cord injury in a preclinical model

Damage to the spinal cord triggers a local complex inflammatory reaction that results in irreversible impairments or complete loss of motor function. The evidence suggested that inhibiting the pro-inflammatory macrophage/microglia (M1 subsets) and stimulating the anti-inflammatory macrophage/microglia (M2 subsets) are potential strategies for the treatment of neuroinflammation-related diseases. We evaluated the potentially protective effect of Ac-SDKP as an endogenous tetrapeptide on rat spinal cord injury (SCI). Wistar rats were subjected to a weight-drop contusion model and were treated with Ac-SDKP (0.8 mg/kg) given subcutaneously once a day for 7 days starting at two clinically relevant times, at 2 h or 6 h post-injury. The effect of Ac-SDKP was assessed by motor functional analysis, real-time PCR (CD86 and CD206 mRNA), western blot (caspase-3), ELISA (TNF-a, IL-10), and histological analysis (toluidine blue staining). Ac-SDKP improved locomotor recovery and rescue motor neuron loss after SCI. Moreover, a decreased in TNF-a level as well as caspase 3 protein levels occurred in the lesion epicenter of the spinal cord following treatment. In addition, CD206 mRNA expression level increased significantly in Ac-SDKP treated rats compared with SCI. Together these data suggest that Ac-SDKP might be a novel immunomodulatory drug. It may be beneficial for the treatment of SCI with regards to increasing CD206 gene expression and suppress inflammatory cytokine to improve motor function and reducing histopathological lesion.

High drug-loaded microspheres enabled by controlled in-droplet precipitation promote functional recovery after spinal cord injury

Drug delivery systems with high content of drug can minimize excipients administration, reduce side effects, improve therapeutic efficacy and/or promote patient compliance. However, engineering such systems is extremely challenging, as their loading capacity is inherently limited by the compatibility between drug molecules and carrier materials. To mitigate the drug-carrier compatibility limitation towards therapeutics encapsulation, we developed a sequential solidification strategy. In this strategy, the precisely controlled diffusion of solvents from droplets ensures the fast in-droplet precipitation of drug molecules prior to the solidification of polymer materials. After polymer solidification, a mass of drug nanoparticles is embedded in the polymer matrix, forming a nano-in-micro structured microsphere. All the obtained microspheres exhibit long-term storage stability, controlled release of drug molecules, and most importantly, high mass fraction of therapeutics (21.8–63.1 wt%). Benefiting from their high drug loading degree, the nano-in-micro structured acetalated dextran microspheres deliver a high dose of methylprednisolone (400 μg) within the limited administration volume (10 μL) by one single intrathecal injection. The amount of acetalated dextran used was 1/433 of that of low drug-loaded microspheres. Moreover, the controlled release of methylprednisolone from high drug-loaded microspheres contributes to improved therapeutic efficacy and reduced side effects than low drug-loaded microspheres and free drug in spinal cord injury therapy.

High drug loading improves therapeutic efficacy and reduces side effects in drug delivery. Here, the authors use controlled diffusion of solvents to precipitate drug nanoparticles in polymer particles while the polymer is solidifying and demonstrate the particles for drug delivery in a spinal cord injury model.

Neuroinflammation and Scarring After Spinal Cord Injury: Therapeutic Roles of MSCs on Inflammation and Glial Scar

Transected axons are unable to regenerate after spinal cord injury (SCI). Glial scar is thought to be responsible for this failure. Regulating the formation of glial scar post-SCI may contribute to axonal regrow. Over the past few decades, studies have found that the interaction between immune cells at the damaged site results in a robust and persistent inflammatory response. Current therapy strategies focus primarily on the inhibition of subacute and chronic neuroinflammation after the acute inflammatory response was executed. Growing evidences have documented that mesenchymal stem cells (MSCs) engraftment can be served as a promising cell therapy for SCI. Numerous studies have shown that MSCs transplantation can inhibit the excessive glial scar formation as well as inflammatory response, thereby facilitating the anatomical and functional recovery. Here, we will review the effects of inflammatory response and glial scar formation in spinal cord injury and repair. The role of MSCs in regulating neuroinflammation and glial scar formation after SCI will be reviewed as well.