Polyvinyl alcohol-polyvinyl pyrrolidone thin films provide local short-term release of anti-inflammatory agents post spinal cord injury

Biodegradable bilayer hydrogel membranes loaded with bazedoxifene attenuate blood-spinal cord barrier disruption via the NF-κB pathway after acute spinal cord injury

After spinal cord injury (SCI), blood-spinal cord barrier (BSCB) disruption and hemorrhage lead to blood cell infiltration and progressive secondary injuries. Therefore, early restoration of the BSCB represents a key step in the treatment of SCI. Bazedoxifene (BZA), a third-generation estrogen receptor modulator, has recently been reported to inhibit inflammation and alleviate blood-brain barrier disruption caused by traumatic brain injury, attracting great interest in the field of central nervous system injury and repair. However, whether BZA can attenuate BSCB disruption and contribute to SCI repair remains unknown. Here, we developed a new type of biomaterial carrier and constructed a BZA-loaded HSPT (hyaluronic acid (HA), sodium alginate (SA), polyvinyl alcohol (PVA), tetramethylpropane (TPA) material construction) (HSPT@Be) system to effectively deliver BZA to the site of SCI. We found that HSPT@Be could significantly reduce inflammation in the spinal cord in SCI rats and attenuate BSCB disruption by providing covering scaffold, inhibiting oxidative stress, and upregulating tight junction proteins, which was mediated by regulation of the NF-κB/MMP signaling pathway. Importantly, functional assessment showed the evident improvement of behavioral functions in the HSPT@Be-treated SCI rats. These results indicated that HSPT@Be can attenuate BSCB disruption via the NF-κB pathway after SCI, shedding light on its potential therapeutic benefit for SCI. STATEMENT OF SIGNIFICANCE: After spinal cord injury, blood-spinal cord barrier disruption and hemorrhage lead to blood cell infiltration and progressive secondary injuries. Bazedoxifene has recently been reported to inhibit inflammation and alleviate blood-brain barrier disruption caused by traumatic brain injury. However, whether BZA can attenuate BSCB disruption and contribute to SCI repair remains unknown. In this study, we developed a new type of biomaterial carrier and constructed a bazedoxifene-loaded HSPT (HSPT@Be) system to efficiently treat SCI. HSPT@Be could provide protective coverage, inhibit oxidative stress, and upregulate tight junction proteins through NF-κB/MMP pathway both in vivo and in vitro, therefore attenuating BSCB disruption. Our study fills the application gap of biomaterials in BSCB restoration.

The Application of Biomaterials in Spinal Cord Injury

The spinal cord and the brain form the central nervous system (CNS), which is the most important part of the body. However, spinal cord injury (SCI) caused by external forces is one of the most difficult types of neurological injury to treat, resulting in reduced or even absent motor, sensory and autonomic functions. It leads to the reduction or even disappearance of motor, sensory and self-organizing nerve functions. Currently, its incidence is increasing each year worldwide. Therefore, the development of treatments for SCI is urgently needed in the clinic. To date, surgery, drug therapy, stem cell transplantation, regenerative medicine, and rehabilitation therapy have been developed for the treatment of SCI. Among them, regenerative biomaterials that use tissue engineering and bioscaffolds to transport cells or drugs to the injured site are considered the most promising option. In this review, we briefly introduce SCI and its molecular mechanism and summarize the application of biomaterials in the repair and regeneration of tissue in various models of SCI. However, there is still limited evidence about the treatment of SCI with biomaterials in the clinic. Finally, this review will provide inspiration and direction for the future study and application of biomaterials in the treatment of SCI.

Conducting molybdenum sulfide/graphene oxide/polyvinyl alcohol nanocomposite hydrogel for repairing spinal cord injury

A sort of composite hydrogel with good biocompatibility, suppleness, high conductivity, and anti-inflammatory activity based on polyvinyl alcohol (PVA) and molybdenum sulfide/graphene oxide (MoS₂/GO) nanomaterial has been developed for spinal cord injury (SCI) restoration. The developed (MoS₂/GO/PVA) hydrogel exhibits excellent mechanical properties, outstanding electronic conductivity, and inflammation attenuation activity. It can promote neural stem cells into neurons differentiation as well as inhibit the astrocytes development in vitro. In addition, the composite hydrogel shows a high anti-inflammatory effect. After implantation of the composite hydrogel in mice, it could activate the endogenous regeneration of the spinal cord and inhibit the activation of glial cells in the injured area, thus resulting in the recovery of locomotor function. Overall, our work provides a new sort of hydrogels for SCI reparation, which shows great promise for improving the dilemma in SCI therapy.

Polymer scaffolds facilitate spinal cord injury repair

During the past decades, improving patient neurological recovery following spinal cord injury (SCI) has remained a challenge. An effective treatment for SCI would not only reduce fractured elements and isolate developing local glial scars to promote axonal regeneration but also ameliorate secondary effects, including inflammation, apoptosis, and necrosis. Three-dimensional (3D) scaffolds provide a platform in which these mechanisms can be addressed in a controlled manner. Polymer scaffolds with favorable biocompatibility and appropriate mechanical properties have been engineered to minimize cicatrization, customize drug release, and ensure an unobstructed space to promote cell growth and differentiation. These properties make polymer scaffolds an important potential therapeutic platform. This review highlights the recent developments in polymer scaffolds for SCI engineering. STATEMENT OF SIGNIFICANCE: How to improve the efficacy of neurological recovery after spinal cord injury (SCI) is always a challenge. Tissue engineering provides a promising strategy for SCI repair, and scaffolds are one of the most important elements in addition to cells and inducing factors. The review highlights recent development and future prospects in polymer scaffolds for SCI therapy. The review will guide future studies by outlining the requirements and characteristics of polymer scaffold technologies employed against SCI. Additionally, the peculiar properties of polymer materials used in the therapeutic process of SCI also have guiding significance to other tissue engineering approaches.

Biomaterial strategies for limiting the impact of secondary events following spinal cord injury

The nature of traumatic spinal cord injury (SCI) often involves limited recovery and long-term quality of life complications. The initial injury sets off a variety of secondary cascades, which result in an expanded lesion area. Ultimately, the native tissue fails to regenerate. As treatments are developed in the laboratory, the management of this secondary cascade is an important first step in achieving recovery of normal function. Current literature identifies four broad targets for intervention: inflammation, oxidative stress, disruption of the blood-spinal cord barrier, and formation of an inhibitory glial scar. Because of the complex and interconnected nature of these events, strategies that combine multiple therapies together show much promise. Specifically, approaches that rely on biomaterials to perform a variety of functions are generating intense research interest. In this review, we examine each target and discuss how biomaterials are currently used to address them. Overall, we show that there are an impressive amount of biomaterials and combinatorial treatments which show good promise for slowing secondary events and improving outcomes. If more emphasis is placed on growing our understanding of how materials can manage secondary events, treatments for SCI can be designed in an increasingly rational manner, ultimately improving their potential for translation to the clinic.

Development and characterization of novel polyurethane films impregnated with tolfenamic acid for therapeutic applications

The present study deals with the preparation of polyurethane (PU) films impregnated with a nonsteroidal anti-inflammatory drug, tolfenamic acid (TA). Solvent evaporation technique has been employed for the preparation of TA-PU films in two different ratios of 1 : 2 and 1 : 5 in Tetrahydrofuran (THF) or THF-ethanol mixtures. The prepared films were characterized using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and release studies. The results indicate transformation of crystalline TA to its amorphous form. The degree of crystallinity changes both by increasing the polymer concentration and solvent used for the film preparations. The release profiles of TA were also found to be affected, showing a decrease from approximately 50% to 25% from 1 : 2 to 1 : 5 ratios, respectively.

Biomaterials for spinal cord repair

Spinal cord injury (SCI) results in permanent loss of function leading to often devastating personal, economic and social problems. A contributing factor to the permanence of SCI is that damaged axons do not regenerate, which prevents the re-establishment of axonal circuits involved in function. Many groups are working to develop treatments that address the lack of axon regeneration after SCI. The emergence of biomaterials for regeneration and increased collaboration between engineers, basic and translational scientists, and clinicians hold promise for the development of effective therapies for SCI. A plethora of biomaterials is available and has been tested in various models of SCI. Considering the clinical relevance of contusion injuries, we primarily focus on polymers that meet the specific criteria for addressing this type of injury. Biomaterials may provide structural support and/or serve as a delivery vehicle for factors to arrest growth inhibition and promote axonal growth. Designing materials to address the specific needs of the damaged central nervous system is crucial and possible with current technology. Here, we review the most prominent materials, their optimal characteristics, and their potential roles in repairing and regenerating damaged axons following SCi.