Comparison of systemic and localized carrier-mediated delivery of methylprednisolone succinate for treatment of acute spinal cord injury

Administration of methylprednisolone do not affect the spinal scar component of spinal cord injury

OBJECTIVE

The aim of this study is to evaluate the impact of methylprednisolone (MP) on scar composition following spinal cord injury (SCI).

DESIGN

A total of 40 adult Sprague Dawley rats underwent right hemisection injuries to the spinal cord.

INTERVENTIONS

The rats were randomly divided into two groups: the vehicle group and the MP group. In the MP group, rats received intraperitoneal injections of MP at a dose of 30 mg/kg for 7 consecutive days, while the vehicle group received intraperitoneal injections of saline as a control. Weekly assessments of hindlimb performance in the rat models were conducted using the Basso-Beattie-Bresnahan test (BBB) score and the horizontal ladder-walking test. Changes in scar components were identified through immunofluorescence staining, and an axonal regeneration assay was employed to evaluate regrowth under inhibitory conditions.

RESULTS

The administration of MP led to a significant improvement in BBB scores compared to the control group at 7 days post-injury, although this improvement was not consistent. Furthermore, rats in the MP group did not demonstrate progressive improvement in horizontal ladder walking. Notably, there were no significant changes in the content of scar components in the injured area following MP treatment, and the axon length of neurons treated with MP did not exhibit significant extension compared to the vehicle group.

CONCLUSIONS

Our findings indicate that the administration of MP does not effectively enhance hindlimb motor function or promote neuronal axon growth within a scarred environment after SCI.

Zeolitic imidazole framework-8 loaded gelatin methacryloyl microneedles: A transdural and controlled-release drug delivery system attenuates neuroinflammation after spinal cord injury

Spinal cord injury (SCI) is a matter of significant clinical concern, often treated through early surgical decompression along with methylprednisolone sodium succinate (MPSS). However, the side effects and the unsatisfactory focal concentration of MPSS have limited its further applications. To address this limitation, herein, a versatile drug delivery system of zeolitic imidazole framework-8 (ZIF-8) and gelatin methacryloyl microneedles (GelMA MNs) was developed for stable, transdural, and controlled sustained release of drugs in SCI. The microneedles were used to create tiny pores in the dura mater, allowing for the direct administration of drugs into the spinal cord. ZIF-8 provided a secondary extended release once they were separated from the microneedles. To attenuate the neuroinflammation, MPSS was selected. Such a combination of ZIF-8 and GelMA MNs was able to prolong the release period of MPSS to five days. The system showed transdural capacity, reduction of M1 polarization, and decrease in NLRP3-positive inflammasome and proinflammatory cytokines. In vivo studies indicated that this novel drug delivery strategy could constrict the inflammatory microenvironment, reduce glial scar formation, and promote neural regeneration. Thus, this versatile drug delivery system provides an up-and-coming alternative for stable, transdural, and controlled sustained release of drugs to those suffering from SCI.

Microneedle/CD-MOF-mediated transdural controlled release of methylprednisolone sodium succinate after spinal cord injury

A new method of transdural delivering drugs to the spinal cord has been developed, involving the use of microneedles (MNs) and a β-cyclodextrin metal-organic framework (CD-MOF). This epidural microneedle array, dubbed MNs@CD-MOF@MPSS, can be utilized to deliver methylprednisolone sodium succinate (MPSS) to the site of spinal cord injury (SCI) in a controlled manner. MNs allows to generate micropores in the dura for direct drug delivery to the spinal cord, overcoming tissue barriers and targeting damaged regions. Additionally, the CD-MOF provides a secondary extended release after separating from the MNs. In in vitro study, inward MNs increased cellular absorption of MPSS and then reduced LPS-induced M1 polarization of microglia. And animal studies have shown that this method of drug delivery results in improved BMS scores and a reduction in M1 phenotype microphage and glial scar formation. Furthermore, the downregulation of the NLRP3-positive inflammasome and related pro-inflammatory cytokines was observed. In conclusion, this new drug platform has potential for clinical application in spinal cord diseases and is a valuable composite for minimally transdural controlled drug delivery. STATEMENT OF SIGNIFICANCE: This research presents a new epidural microneedle patch made up of microneedles (MNs) and a β-cyclodextrin metal-organic framework (CD-MOF). The epidural microneedle patch boasts high drug loading capacity, the ability to penetrate the dura, and controlled release. When loaded with methylprednisolone sodium succinate (MPSS), it effectively reduces inflammation and improves neurological function after spinal cord injury. Therefore, it is a novel and promising drug platform for the treatment of spinal cord diseases in a clinical setting.

Functional State of the Motor Centers of the Lumbar Spine after Contusion (Th8-Th9) with Application of Methylprednisolone-Copolymer at the Site of Injury

Spinal cord injuries must be treated as soon as possible. Studies of NASCIS protocols have questioned the use of methylprednisolone therapy. This study aimed to evaluate the effect of local delivery of methylprednisolone succinate in combination with a tri-block copolymer in rats with spinal cord injury. The experiments were conducted in accordance with the bioethical guidelines. We evaluated the state of the motor centers below the level of injury by assessing the amplitude of evoked motor responses in the hind limb muscles of rats during epidural stimulation. Kinematic analysis was performed to examine the stepping cycle in each rat. Trajectories of foot movements were plotted to determine the range of limb motion, maximum foot lift height, and lateral deviation of the foot in rats on the 21st day after spinal cord injury. We have shown that the local application of methylprednisolone succinate in combination with block copolymer leads to recovery of center excitability by 21 days after injury. In rats, they recovered weight-supported locomotion, directional control of walking, and balance. The proposed assessment method provides valuable information on gait disturbances following injury and can be utilized to evaluate the quality of therapeutic interventions.

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.

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.

Selective Calpain Inhibition Improves Functional and Histopathological Outcomes in a Canine Spinal Cord Injury Model

Calpain activation has been implicated in various pathologies, including neurodegeneration. Thus, calpain inhibition could effectively prevent spinal cord injury (SCI) associated with neurodegeneration. In the current study, a dog SCI model was used to evaluate the therapeutic potential of a selective calpain inhibitor (PD150606) in combination with methylprednisolone sodium succinate (MPSS) as an anti-inflammatory drug. SCI was experimentally induced in sixteen mongrel dogs through an epidural balloon compression technique. The dogs were allocated randomly into four groups: control, MPSS, PD150606, and MPSS+PD150606. Clinical evaluation, serum biochemical, somatosensory evoked potentials, histopathological, and immunoblotting analyses were performed to assess treated dogs during the study. The current findings revealed that the combined administration of MPSS+PD150606 demonstrated considerably lower neuronal loss and microglial cell infiltration than the other groups, with a significant improvement in the locomotor score. The increased levels of inflammatory markers (GFAP and CD11) and calcium-binding proteins (Iba1 and S100) were significantly reduced in the combination group and to a lesser extent in MPSS or PD150606 treatment alone. Interestingly, the combined treatment effectively inhibited the calpain-induced cleavage of p35, limited cdk5 activation, and inhibited tau phosphorylation. These results suggest that early MPSS+PD150606 therapy after acute SCI may prevent subsequent neurodegeneration via calpain inhibition.

The Automatization of the Gait Analysis by the Vicon Video System: A Pilot Study

The quality of modern measuring instruments has a strong influence on the speed of diagnosing diseases of the human musculoskeletal system. The research is focused on automatization of the method of gait analysis. The study involved six healthy subjects. The subjects walk straight. Each subject made several gait types: casual walking and imitation of a non-standard gait, including shuffling, lameness, clubfoot, walking from the heel, rolling from heel to toe, walking with hands in pockets, and catwalk. Each type of gait was recorded three times. For video fixation, the Vicon Nexus system was used. A total of 27 reflective markers were placed on the special anatomical regions. The goniometry methods were used. The walk data were divided by steps and by step phases. Kinematic parameters for estimation were formulated and calculated. An approach for data clusterization is presented. For this purpose, angle data were interpolated and the interpolation coefficients were used for clustering the data. The data were processed and four cluster groups were found. Typical angulograms for cluster groups were presented. For each group, average angles were calculated. A statistically significant difference was found between received cluster groups.

Methylprednisolone as an Adjunct to Local Infiltration on Laminoplasty or Laminectomy before Wound Closure: A Randomized Controlled Trial

TrialDesign. Patients undergoing laminoplasty and laminectomy often experience severe postoperative pain. Local infiltration analgesia during spine surgery significantly reduces postoperative pain, which only upholds for a short time. Whether methylprednisolone and local anaesthetics are better than local anaesthetics alone in postoperative analgesia is yet to be determined. The primary aim of this research was the postoperative evaluation of efficacy and safety of methylprednisolone when used as an adjunct to local anaesthesia, ropivacaine, before wound closure after surgical procedures, laminoplasty or laminectomy. Methods. 132 patients were divided with a ratio of 1 : 1 into methylprednisolone-ropivacaine and ropivacaine alone groups. Every 30 ml of local infiltration solution consisted of 15 ml of 1% ropivacaine with 14 ml of saline along with 1 ml of 40 mg methylprednisolone and 15 ml of 1% ropivacaine with 15 ml of saline in methylprednisolone-ropivacaine group and ropivacaine group, respectively. The standardization of the study solution depended on the number of levels involved in surgery. Primary outcome was the 48-hour cumulative sufentanil demand. Results. Demographic characters and surgical variables among the groups were identical. The average 48-hour cumulative sufentanil demand was 32.5 ± 20.6 μg in the methylprednisolone-ropivacaine group and 50.9 ± 27.2 μg in the ropivacaine group ( $p<0.001$ ). The estimated median time of demand of the first analgesia via patient-controlled analgesia (PCA) pump was 2.5 hours and 2 hours in the methylprednisolone-ropivacaine group and the ropivacaine group, respectively (hazard ratio (HR) was 0.53, with 95% Cl 0.33 to 0.87 and Log-rank of $p=0.0019$ ). Conclusion. The infiltration of methylprednisolone as adjunct ropivacaine before wound closure is a safe and efficient strategy for pain management following laminoplasty or laminectomy.

Construction of tissue-customized hydrogels from cross-linkable materials for effective tissue regeneration

Hydrogels are prevalent scaffolds for tissue regeneration because of their hierarchical architectures along with outstanding biocompatibility and unique rheological and mechanical properties. For decades, researchers have found that many materials (natural, synthetic, or hybrid) can form hydrogels using different cross-linking strategies. Traditional strategies for fabricating hydrogels include physical, chemical, and enzymatical cross-linking methods. However, due to the diverse characteristics of different tissues/organs to be regenerated, tissue-customized hydrogels need to be developed through precisely controlled processes, making the manufacture of hydrogels reliant on novel cross-linking strategies. Thus, hybrid cross-linkable materials are proposed to tackle this challenge through hybrid cross-linking strategies. Here, different cross-linkable materials and their associated cross-linking strategies are summarized. From the perspective of the major characteristics of the target tissues/organs, we critically analyze how different cross-linking strategies are tailored to fit the regeneration of such tissues and organs. To further advance this field, more appropriate cross-linkable materials and cross-linking strategies should be investigated. In addition, some innovative technologies, such as 3D bioprinting, the internet of medical things (IoMT), and artificial intelligence (AI), are also proposed to improve the development of hydrogels for more efficient tissue regeneration.

Methylprednisolone Induces Neuro-Protective Effects via the Inhibition of A1 Astrocyte Activation in Traumatic Spinal Cord Injury Mouse Models

Traumatic spinal cord injury (TSCI) leads to pathological changes such as inflammation, edema, and neuronal apoptosis. Methylprednisolone (MP) is a glucocorticoid that has a variety of beneficial effects, including decreasing inflammation and ischemic reaction, as well as inhibiting lipid peroxidation. However, the efficacy and mechanism of MP in TSCI therapy is yet to be deciphered. In the present study, MP significantly attenuated the apoptotic effects of H₂O₂ in neuronal cells. Western blot analysis demonstrated that the levels of apoptotic related proteins, Bax and cleaved caspase-3, were reduced while levels of anti-apoptotic Bcl-2 were increased. In vivo TUNEL assays further demonstrated that MP effectively protected neuronal cells from apoptosis after TSCI, and was consistent with in vitro studies. Furthermore, we demonstrated that MP could decrease expression levels of IBA1, Il-1α, TNFα, and C3 and suppress A1 neurotoxic reactive astrocyte activation in TSCI mouse models. Neurological function was evaluated using the Basso Mouse Scale (BMS) and Footprint Test. Results demonstrated that the neurological function of MP-treated injured mice was significantly increased. In conclusion, our study demonstrated that MP could attenuate astrocyte cell death, decrease microglia activation, suppress A1 astrocytes activation, and promote functional recovery after acute TSCI in mouse models.

Canonical transient receptor potential channels and their modulators: biology, pharmacology and therapeutic potentials

Canonical transient receptor potential channels (TRPCs) are nonselective, high calcium permeability cationic channels. The TRPCs family includes TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7. These channels are widely expressed in the cardiovascular and nervous systems and exist in many other human tissues and cell types, playing several crucial roles in the human physiological and pathological processes. Hence, the emergence of TRPCs modulators can help investigate these channels’ applications in health and disease. It is worth noting that the TRPCs subfamilies have structural and functional similarities, which presents a significant difficulty in screening and discovering of TRPCs modulators. In the past few years, only a limited number of selective modulators of TRPCs were detected; thus, additional research on more potent and more selective TRPCs modulators is needed. The present review focuses on the striking desired therapeutic effects of TRPCs modulators, which provides intel on the structural modification of TRPCs modulators and further pharmacological research. Importantly, TRPCs modulators can significantly facilitate future studies of TRPCs and TRPCs related diseases.