Functional resveratrol-biodegradable manganese doped silica nanoparticles for the spinal cord injury treatment

Biomaterial-based strategies: a new era in spinal cord injury treatment

Enhancing neurological recovery and improving the prognosis of spinal cord injury have gained research attention recently. Spinal cord injury is associated with a complex molecular and cellular microenvironment. This complexity has prompted researchers to elucidate the underlying pathophysiological mechanisms and changes and to identify effective treatment strategies. Traditional approaches for spinal cord injury repair include surgery, oral or intravenous medications, and administration of neurotrophic factors; however, the efficacy of these approaches remains inconclusive, and serious adverse reactions continue to be a concern. With advancements in tissue engineering and regenerative medicine, emerging strategies for spinal cord injury repair now involve nanoparticle-based nanodelivery systems, scaffolds, and functional recovery techniques that incorporate biomaterials, bioengineering, stem cell, and growth factors as well as three-dimensional bioprinting. Ideal biomaterial scaffolds should not only provide structural support for neuron migration, adhesion, proliferation, and differentiation but also mimic the mechanical properties of natural spinal cord tissue. Additionally, these scaffolds should facilitate axon growth and neurogenesis by offering adjustable topography and a range of physical and biochemical cues. The three-dimensionally interconnected porous structure and appropriate physicochemical properties enabled by three-dimensional biomimetic printing technology can maximize the potential of biomaterials used for treating spinal cord injury. Therefore, correct selection and application of scaffolds, coupled with successful clinical translation, represent promising clinical objectives to enhance the treatment efficacy for and prognosis of spinal cord injury. This review elucidates the key mechanisms underlying the occurrence of spinal cord injury and regeneration post-injury, including neuroinflammation, oxidative stress, axon regeneration, and angiogenesis. This review also briefly discusses the critical role of nanodelivery systems used for repair and regeneration of injured spinal cord, highlighting the influence of nanoparticles and the factors that affect delivery efficiency. Finally, this review highlights tissue engineering strategies and the application of biomaterial scaffolds for the treatment of spinal cord injury. It discusses various types of scaffolds, their integrations with stem cells or growth factors, and approaches for optimization of scaffold design.

Nanoparticles for the treatment of spinal cord injury

Spinal cord injuries lead to significant loss of motor, sensory, and autonomic functions, presenting major challenges in neural regeneration. Achieving effective therapeutic concentrations at injury sites has been a slow process, partly due to the difficulty of delivering drugs effectively. Nanoparticles, with their targeted delivery capabilities, biocompatibility, and enhanced bioavailability over conventional drugs, are garnering attention for spinal cord injury treatment. This review explores the current mechanisms and shortcomings of existing treatments, highlighting the benefits and progress of nanoparticle-based approaches. We detail nanoparticle delivery methods for spinal cord injury, including local and intravenous injections, oral delivery, and biomaterial-assisted implantation, alongside strategies such as drug loading and surface modification. The discussion extends to how nanoparticles aid in reducing oxidative stress, dampening inflammation, fostering neural regeneration, and promoting angiogenesis. We summarize the use of various types of nanoparticles for treating spinal cord injuries, including metallic, polymeric, protein-based, inorganic non-metallic, and lipid nanoparticles. We also discuss the challenges faced, such as biosafety, effectiveness in humans, precise dosage control, standardization of production and characterization, immune responses, and targeted delivery in vivo. Additionally, we explore future directions, such as improving biosafety, standardizing manufacturing and characterization processes, and advancing human trials. Nanoparticles have shown considerable progress in targeted delivery and enhancing treatment efficacy for spinal cord injuries, presenting significant potential for clinical use and drug development.

Spinal cord injury repair based on drug and cell delivery: From remodeling microenvironment to relay connection formation

Spinal cord injury (SCI) presents a formidable challenge in clinical settings, resulting in sensory and motor function loss and imposing significant personal and societal burdens. However, owning to the adverse microenvironment and limited regenerative capacity, achieving complete functional recovery after SCI remains elusive. Additionally, traditional interventions including surgery and medication have a series of limitations that restrict the effectiveness of treatment. Recently, tissue engineering (TE) has emerged as a promising approach for promoting neural regeneration and functional recovery in SCI, which can effectively delivery drugs into injury site and delivery cells and improve the survival and differential. Here, we outline the main pathophysiology events of SCI and the adverse microenvironment post injury, further discuss the materials and common assembly strategies used for scaffolds in SCI treatment, expound on the latest advancements in treatment methods based on materials and scaffolds for drug and cell delivery in detail, and propose future directions for SCI repair with TE and highlight potential clinical applications.

Neutrophil membrane-coated multifunctional biomimetic nanoparticles for spinal cord injuries

Spinal cord injury (SCI) is one of the most complex diseases. After SCI, severe secondary injuries can cause intense inflammatory storms and oxidative stress responses, leading to extensive neuronal apoptosis. Effective regulation of inflammation and oxidative stress after SCI remains an unresolved challenge. In this study, resveratrol-loaded nanoparticles coated with neutrophil membranes (NMR) were prepared using the emulsion-solvent evaporation method and membrane encapsulation technology. Multifunctional biomimetic nanoparticles retain neutrophil membrane-related receptors and possess a strong adsorption capacity for inflammatory factors. As a drug carrier, NMR can sustainably release resveratrol for >72 h. Moreover, co-culture studies in vitro show that the NMR help regulate macrophage polarization to relieve inflammatory response, reduce intracellular reactive oxygen species by approximately 50%, and improve mitochondrial membrane potential to alleviate oxidative stress. After injecting NMR into the injury site, it reduces early apoptosis, inhibit scar formation, and promote neural network recovery to improve motor function. This study demonstrates the anti-inflammatory, antioxidant, and neuroprotective effects of NMR, thus providing a novel therapeutic strategy for SCI.

Synergic effects of core-shell nanospheres and magnetic field for sciatic nerve regeneration in decellularized artery conduits with Schwann cells

Numerous conduits have been developed to improve peripheral nerve regeneration. However, challenges remain, including remote control of conduit function, and programmed cell behaviors like orientation. We synthesized Fe3O4-MnO2@Zirconium-based Metal-organic frameworks@Retinoic acid (FMZMR) core-shell and assessed their impact on Schwann cell function and behavior within conduits made from decellularized human umbilical arteries (DHUCA) under magnetic field (MF). FMZMR core-shell, featuring a spherical porous structure and catalytic properties, effectively scavenges radicals and facilitates controlled drug release under MF. The histology of the DHUCA indicates effective decellularization with adequate tensile strength and Young's modulus for sciatic nerve regeneration. In-vitro results demonstrate that FMZMR core-shell is biocompatible and promotes Schwann cell proliferation through remotely controlled drug release. Furthermore, its synergy with MF enhances cell orientation and increases neurite length by ~ 1.93-fold. Functional and histological evaluations indicate that the FMZMR core-shell combined with MF promotes nerve regeneration, decreases muscle atrophy, and enhances new neuron growth and myelin formation, without negatively affecting vital tissues. This study suggests that the synergistic effect of FMZMR core-shell with MF can alleviate some of the treatment challenges.

Biomaterial-mediated delivery of traditional Chinese medicine ingredients for spinal cord injury: a systematic review

Objective

Biomaterials loaded with ingredients derived from traditional Chinese medicine (TCM) are viewed as a promising strategy for treating spinal cord injury (SCI). However, a comprehensive analysis of the existing literature on this topic has not yet been conducted. Therefore, this paper systematically reviews researches related to this approach, aiming to identify gaps and shortcomings in the field.

Methods

PubMed, EMBASE, Web of Science, Chinese Biomedical Literature, Wanfang, and China National Knowledge Infrastructure (CNKI) were searched for retrieving studies on biomaterials loaded with TCM ingredients published from their inception to October 2024. Two reviewers performed screening of search results, information extraction, and literature quality assessment independently.

Results

For this systematic review, 41 publications were included. Six TCM ingredients-paclitaxel, curcumin, tetramethylpyrazine, resveratrol, berberine, and tanshinone IIA were combined with biomaterials for treatment of SCI. Biomaterials were categorized into hydrogels, biodegradable scaffolds, nanoparticles, and microspheres according to the type of scaffold. These drug delivery systems exhibit commendable biocompatibility, drug-loading capacity, and drug-release capabilities, and in combination with TCM ingredients, synergistically contribute to anti-oxidative stress, anti-inflammatory, neuroprotective, and anti-apoptotic effects.

Conclusion

These studies demonstrated the efficacy of biomaterials loaded with TCM ingredients in facilitating motor function recovery and neuroprotection in SCI rats, providing evidence for future research. However, in the complex microenvironment of SCI, achieving the maximum drug loading capacity of TCM ingredients within biomaterials, along with sustained and controlled release to fully exert their pharmacological effects, remains a major challenge for future research.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/ identifier CRD42024505000.

Manganese-derived biomaterials for tumor diagnosis and therapy

Manganese (Mn) is widely recognized owing to its low cost, non-toxic nature, and versatile oxidation states, leading to the emergence of various Mn-based nanomaterials with applications across diverse fields, particularly in tumor diagnosis and therapy. Systematic reviews specifically addressing the tumor diagnosis and therapy aspects of Mn-derived biomaterials are lacking. This review comprehensively explores the physicochemical characteristics and synthesis methods of Mn-derived biomaterials, emphasizing their role in tumor diagnostics, including magnetic resonance imaging, photoacoustic and photothermal imaging, ultrasound imaging, multimodal imaging, and biodetection. Moreover, the advantages of Mn-based materials in tumor treatment applications are discussed, including drug delivery, tumor microenvironment regulation, synergistic photothermal, photodynamic, and chemodynamic therapies, tumor immunotherapy, and imaging-guided therapy. The review concludes by providing insights into the current landscape and future directions for Mn-driven advancements in the field, serving as a comprehensive resource for researchers and clinicians.

Nanotherapeutics for Alleviating Anesthesia-Associated Complications

Current management of anesthesia-associated complications falls short in terms of both efficacy and safety. Nanomaterials with versatile properties and unique nano-bio interactions hold substantial promise as therapeutics for addressing these complications. This review conducts a thorough examination of the existing nanotherapeutics and highlights the strategies for developing prospective nanomedicines to mitigate anesthetics-related toxicity. Initially, general, regional, and local anesthesia along with the commonly used anesthetics and related prevalent side effects are introduced. Furthermore, employing nanotechnology to prevent and alleviate the complications of anesthetics is systematically demonstrated from three aspects, that is, developing 1) safe nano-formulization for anesthetics; 2) nano-antidotes to sequester overdosed anesthetics and alter their pharmacokinetics; 3) nanomedicines with pharmacodynamic activities to treat anesthetics toxicity. Finally, the prospects and challenges facing the clinical translation of nanotherapeutics for anesthesia-related complications are discussed. This work provides a comprehensive roadmap for developing effective nanotherapeutics to prevent and mitigate anesthesia-associated toxicity, which can potentially revolutionize the management of anesthesia complications.

ROS: Executioner of regulating cell death in spinal cord injury

The damage to the central nervous system and dysfunction of the body caused by spinal cord injury (SCI) are extremely severe. The pathological process of SCI is accompanied by inflammation and injury to nerve cells. Current evidence suggests that oxidative stress, resulting from an increase in the production of reactive oxygen species (ROS) and an imbalance in its clearance, plays a significant role in the secondary damage during SCI. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a crucial regulatory molecule for cellular redox. This review summarizes recent advancements in the regulation of ROS-Nrf2 signaling and focuses on the interaction between ROS and the regulation of different modes of neuronal cell death after SCI, such as apoptosis, autophagy, pyroptosis, and ferroptosis. Furthermore, we highlight the pathways through which materials science, including exosomes, hydrogels, and nanomaterials, can alleviate SCI by modulating ROS production and clearance. This review provides valuable insights and directions for reducing neuronal cell death and alleviating SCI through the regulation of ROS and oxidative stress.

CD44-targeting hyaluronic acid-selenium nanoparticles boost functional recovery following spinal cord injury

BACKGROUND

Therapeutic strategies based on scavenging reactive oxygen species (ROS) and suppressing inflammatory cascades are effective in improving functional recovery after spinal cord injury (SCI). However, the lack of targeting nanoparticles (NPs) with powerful antioxidant and anti-inflammatory properties hampers the clinical translation of these strategies. Here, CD44-targeting hyaluronic acid-selenium (HA-Se) NPs were designed and prepared for scavenging ROS and suppressing inflammatory responses in the injured spinal cord, enhancing functional recovery.

RESULTS

The HA-Se NPs were easily prepared through direct reduction of seleninic acid in the presence of HA. The obtained HA-Se NPs exhibited a remarkable capacity to eliminate free radicals and CD44 receptor-facilitated internalization by astrocytes. Moreover, the HA-Se NPs effectively mitigated the secretion of proinflammatory cytokines (such as IL-1β, TNF-α, and IL-6) by microglia cells (BV2) upon lipopolysaccharide-induced inflammation. In vivo experiments confirmed that HA-Se NPs could effectively accumulate within the lesion site through CD44 targeting. As a result, HA-Se NPs demonstrated superior protection of axons and neurons within the injury site, leading to enhanced functional recovery in a rat model of SCI.

CONCLUSIONS

These results highlight the potential of CD44-targeting HA-Se NPs for SCI treatment.

Hydrogel and Nanomedicine-Based Multimodal Therapeutic Strategies for Spinal Cord Injury

Spinal cord injury (SCI) is a severe neurodegenerative disease caused by mechanical and biological factors, manifesting as a loss of motor and sensory functions. Inhibition of injury expansion and even reversal of injury in the acute damage stage of SCI are important strategies for treating this disease. Hydrogels and nanoparticle (NP)-based drugs are the most effective, widely studied, and clinically valuable therapeutic strategies in the field of repair and regeneration. Hydrogels are 3D flow structures that fill the pathological gaps in SCI and provide a microenvironment similar to that of the spinal cord extracellular matrix for nerve cell regeneration. NP-based drugs can easily penetrate the blood-spinal cord barrier, target SCI lesions, and are noninvasive. Hydrogels and NPs as drug carriers can be loaded with various drugs and biological therapeutic factors for slow release in SCI lesions. They help drugs function more efficiently by exerting anti-inflammatory, antioxidant, and nerve regeneration effects to promote the recovery of neurological function. In this review, the use of hydrogels and NPs as drug carriers and the role of both in the repair of SCI are discussed to provide a multimodal strategic reference for nerve repair and regeneration after SCI.

Nanomedicine innovations in spinal cord injury management: Bridging the gap

Spinal cord injury (SCI) has devastating effects on a person's physical, social, and professional well-being. It is a life-altering neurological condition that significantly impacts individuals and their caregivers on a socioeconomic level. Recent advancements in medical therapy have greatly improved the diagnosis, stability, survival rates, and overall well-being of SCI patients. However, there are still limited options available for enhancing neurological outcomes in these patients. The complex pathophysiology of SCI, along with the numerous biochemical and physiological changes that occur in the damaged spinal cord, contribute to this gradual improvement. Currently, there are no therapies that offer the possibility of recovery for SCI, although several therapeutic approaches are being developed. However, these therapies are still in the early stages and have not yet demonstrated effectiveness in repairing the damaged fibers, which hinders cellular regeneration and the full restoration of motor and sensory functions. Considering the importance of nanotechnology and tissue engineering in treating neural tissue injuries, this review focuses on the latest advancements in nanotechnology for SCI therapy and tissue healing. It examines research articles from the PubMed database that specifically address SCI in the field of tissue engineering, with an emphasis on nanotechnology as a therapeutic approach. The review evaluates the biomaterials used for treating this condition and the techniques employed to create nanostructured biomaterials.

Effects of a neurokinin-1 receptor antagonist in the acute phase after thoracic spinal cord injury in a rat model

Objective

Disruption of the blood-spinal cord barrier (BSCB) with subsequent edema formation and further neuroinflammation contributes to aggravation of spinal cord injury (SCI). We aimed to observe the effect of antagonizing the binding of the neuropeptide Substance-P (SP) to its neurokinin-1 (NK1) receptor in a rodent SCI model.

Methods

Female Wistar rats were subjected to a T9 laminectomy with or without (Sham) a T9 clip-contusion/compression SCI, followed by the implantation of an osmotic pump for the continuous, seven-day-long infusion of a NK1 receptor antagonist (NRA) or saline (vehicle) into the intrathecal space. The animals were assessed via MRI, and behavioral tests were performed during the experiment. 7 days after SCI, wet & dry weight and immunohistological analyses were conducted.

Results

Substance-P inhibition via NRA showed limited effects on reducing edema. However, the invasion of T-lymphocytes and the number of apoptotic cells were significantly reduced with the NRA treatment. Moreover, a trend of reduced fibrinogen leakage, endothelial and microglial activation, CS-GAG deposition, and astrogliosis was found. Nevertheless, only insignificant general locomotion recovery could be observed in the BBB open field score and the Gridwalk test. In contrast, the CatWalk gait analysis showed an early onset of recovery in several parameters.

Conclusion

Intrathecal administration of NRA might reinforce the integrity of the BSCB in the acute phase after SCI, potentially attenuating aspects of neurogenic inflammation, reducing edema formation, and improving functional recovery.

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

Background

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.

Methods

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.

Results

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.

Conclusion

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.

Key Parameters for the Rational Design, Synthesis, and Functionalization of Biocompatible Mesoporous Silica Nanoparticles

Over the last few years, research on silica nanoparticles has rapidly increased. Particularly on mesoporous silica nanoparticles (MSNs), as nanocarriers for the treatment of various diseases because of their physicochemical properties and biocompatibility. The use of MSNs combined with therapeutic agents can provide better encapsulation and effective delivery. MSNs as nanocarriers might also be a promising tool to lower the therapeutic dosage levels and thereby to reduce undesired side effects. Researchers have explored several routes to conjugate both imaging and therapeutic agents onto MSNs, thus expanding their potential as theranostic platforms, in order to allow for the early diagnosis and treatment of diseases. This review introduces a general overview of recent advances in the field of silica nanoparticles. In particular, the review tackles the fundamental aspects of silicate materials, including a historical presentation to new silicates and then focusing on the key parameters that govern the tailored synthesis of functional MSNs. Finally, the biomedical applications of MSNs are briefly revised, along with their biocompatibility, biodistribution and degradation. This review aims to provide the reader with the tools for a rational design of biocompatible MSNs for their application in the biomedical field. Particular attention is paid to the role that the synthesis conditions have on the physicochemical properties of the resulting MSNs, which, in turn, will determine their pharmacological behavior. Several recent examples are highlighted to stress the potential that MSNs hold as drug delivery systems, for biomedical imaging, as vaccine adjuvants and as theragnostic agents.