Valproic Acid Labeled Chitosan Nanoparticles Promote the Proliferation and Differentiation of Neural Stem Cells After Spinal Cord Injury

Effects of Valproic Acid Therapy on Rats with Spinal Cord Injury: A Systematic Review and Meta-Analysis

OBJECTIVE

To systematically evaluate the efficacy of valproic acid (VPA) in rats with spinal cord injury (SCI) to reduce the risk of clinical conversion and provide a valuable reference for future animal and clinical studies.

METHODS

We searched scientific databases, including PubMed, Ovid-Embase, Web of Science, and Scopus databases. The relevant literature was searched from the establishment date of the database to June 28, 2023. The search results were screened, data were extracted, and the quality of the literature was evaluated independently by 2 reviewers.

RESULTS

Among 656 nonduplicated references, 14 articles were included for meta-analysis. The summary results showed that the overall Basso, Beattie and Bresnahan scores of the VPA intervention group were significantly higher than those in the control group at 1-6 weeks after VPA intervention. Subgroup analysis showed that the injury model, administration dose, rat strain, country of study, or follow-up duration had no significant effect on the efficacy of VPA on rats with SCI. In addition, mesh analysis showed that high doses of the VPA group had a better effect on SCI rats, compared with the low dose group and the medium dose group.

CONCLUSIONS

To date, this is the first systematic evaluation of the potential effects of VPA on motor recovery in rats with SCI. We concluded that VPA can promote motor recovery in rats with SCI, and higher doses of VPA seem to be more effective in rats with SCI. However, the limited quality and sample of included studies reduced the application of this meta-analysis. In the future, more high-quality, direct comparative studies are needed to explore this issue in depth.

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.

Histone Deacetylase 3 Inhibition Ameliorates Microglia-Mediated Neuro-Inflammation Via the SIRT1/Nrf2 Pathway After Traumatic Spinal Cord Injury

BACKGROUND

Microglial-induced inflammation plays a crucial role in the pathophysiological process of nervous system injury, however, still lacks effective therapeutic agents. Previously, we discovered that the inhibition of histone deacetylase 3 (HDAC3) exerts anti-inflammatory effects after traumatic spinal cord injury (SCI), whereas little is known about its underlying mechanism. Therefore, the present study aimed to explore the effects and potential mechanisms of HDAC3 on neuroinflammation and microglial function.

METHODS

Rats were randomized into 4 groups: sham group, SCI group, SCI + vehicle group, and SCI + RGF966 group. To examine the effect of HDAC3 on neurological deficit after SCI, we gathered data using the Basso Beattie Bresnahan locomotion scale, the inclined plane test, the blood-spinal cord barrier, junction protein expression, and Nissl staining. We also evaluated microglial activation and inflammatory factor levels. Immunofluorescence analysis, immunohistochemical analysis, western blotting, and quantitative real-time polymerase chain reaction were performed to examine the regulation of the Sirtuin 1 (SIRT1)/nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway.

RESULTS

The results showed that HDAC3 inhibition significantly ameliorated Basso-Beattie-Bresnahan (BBB) permeability, brain edema, and improved neurological functions and junction protein levels. Additionally, HDAC3 inhibition significantly inhibited microglial activation, thereby reducing the levels of SCI-induced pro-inflammatory factors. Moreover, HDAC3 inhibition dramatically enhanced the expression of SIRT1 and increased both Nrf2 nuclear accumulation and transcriptional activity, thereby increasing downstream heme oxygenase-1 and NAD(P)H quinone oxidoreductase 1 expression.

CONCLUSIONS

The results of this study suggest that HDAC3 inhibition protects the spinal cord from injury following SCI by inhibiting SCI-induced microglial activation and the subsequent inflammatory response via SIRT1/Nrf2 signaling pathway, highlighting HDAC3 as a potential therapeutic target for the treatment of SCI.

Recent advances in the combination of cellular therapy with stem cells and nanoparticles after a spinal cord injury

Background

Currently, combined therapies could help to reduce long-term sequelae of spinal cord injury (SCI); stem cell therapy at the site of injury in combination with other therapies has shown very promising results that can be transferred to the clinical field. Nanoparticles (NPs) are versatile technologies with applications to medical research for treatments of SCI since they could deliver therapeutic molecules to the target tissue and may help to reduce the side effects of non-targeted therapies. This article's purpose is to analyze and concisely describe the diverse cellular therapies in combination with NPs and their regenerative effect after SCI.

Methods

We reviewed the literature related to combinatory therapy for motor impairment following SCI that has been published by Web of Science, Scopus, EBSCO host, and PubMed databases. The research covers the databases from 2001 to December 2022.

Result

Animal models of SCI have shown that the combination of NPs plus stem cells has a positive impact on neuroprotection and neuroregeneration. Further research is required to better understand the effects and benefits of SCI on a clinical level; therefore, it is necessary to find and select the most effective molecules that are capable of exacerbating the neurorestorative effects of the different stem cells and then try them out on patients after SCI. On the other hand, we consider that synthetic polymers such as poly [lactic-co-glycolic acid] (PLGA) could be a candidate for the design of the first therapeutic strategy that combines NPs with stem cells in patients with SCI. The reasons for the selection are that PLGA has shown important advantages over other NPs, such as being biodegradable, having low toxicity levels, and high biocompatibility; In addition, researchers could control the release time and the biodegradation kinetics, and most importantly, it could be used as NMs on other clinical pathologies (12 studies on www.clinicaltrials.gov) and has been approved by the Federal Food, Drug, and Cosmetic Act (FDA).

Conclusion

The use of cellular therapy and NPs may be a worthwhile alternative for SCI therapy; however, it is expected that the data obtained from interventions after SCI reflect an important variability of molecules combined with NPs. Therefore, it is necessary to properly define the limits of this research to be able to continue to work on the same line. Consequently, the selection of a specific therapeutic molecule and type of NPs plus stem cells are crucial to evaluate its application in clinical trials.

Applications of chitosan-based biomaterials: From preparation to spinal cord injury neuroprosthetic treatment

Spinal cord injury (SCI)-related disabilities are a serious problem in the modern society. Further, the treatment of SCI is highly challenging and is urgently required in clinical practice. Research on nerve tissue engineering is an emerging approach for improving the treatment outcomes of SCI. Chitosan (CS) is a cationic polysaccharide derived from natural biomaterials. Chitosan has been found to exhibit excellent biological properties, such as nontoxicity, biocompatibility, biodegradation, and antibacterial activity. Recently, chitosan-based biomaterials have attracted significant attention for SCI repair in nerve tissue engineering applications. These studies revealed that chitosan-based biomaterials have various functions and mechanisms to promote SCI repair, such as promoting neural cell growth, guiding nerve tissue regeneration, delivering nerve growth factors, and as a vector for gene therapy. Chitosan-based biomaterials have proven to have excellent potential for the treatment of SCI. This review aims to introduce the recent advances in chitosan-based biomaterials for SCI treatment and to highlight the prospects for further application.

Combination Therapy Using Nanomaterials and Stem Cells to Treat Spinal Cord Injuries

As a part of the central nervous system, the spinal cord (SC) provides most of the communications between the brain and other parts of the body. Any damage to SC interrupts this communication, leading to serious problems, which may remain for the rest of their life. Due to its significant impact on patients' quality of life and its exorbitant medical costs, SC injury (SCI) is known as one of the most challengeable diseases in the world. Thus, it is critical to introduce highly translatable therapeutic platforms for SCI treatment. So far, different strategies have been introduced, among which utilizing various types of stem cells is one of the most interesting ones. The capability of stem cells to differentiate into several types of cell lines makes them promising candidates for the regeneration of injured tissues. One of the other interesting and novel strategies for SCI treatment is the application of nanomaterials, which could appear as a carrier for therapeutic agents or as a platform for culturing the cells. Combining these two approaches, stem cells and nanomaterials, could provide promising therapeutic strategies for SCI management. Accordingly, in this review we have summarized some of the recent advancements in which the applications of different types of stem cells and nanomaterials, alone and in combination forms, were evaluated for SCI treatment.

Rosiglitazone Ameliorates Spinal Cord Injury via Inhibiting Mitophagy and Inflammation of Neural Stem Cells

BACKGROUND

Neurodegenerative diseases, such as Alzheimer's disease, and traumatic brain and spinal cord injury (SCI) are prevalent in clinical practice. Inhibition of hyperactive inflammation and proliferation of endogenous neural stem cells (NSCs) is a promising treatment strategy for SCI. Our previous studies demonstrated the beneficial effects of rosiglitazone (Rosi) on SCI, but its roles in inflammation inhibition and proliferation of NSCs are unknown.

METHODS

SCI in a rat model was established, and the effects of Rosi on motor functions were assessed. The effects of Rosi on NSC proliferation and the underlying mechanisms were explored in details.

RESULTS

We showed that Rosi ameliorated impairment of moto functions in SCI rats, inhibited inflammation, and promoted proliferation of NSCs in vivo. Rosi increased ATP production through enhancing glycolysis but not oxidative phosphorylation. Rosi reduced mitophagy by downregulating PTEN-induced putative kinase 1 (PINK1) transcription to promote NSC proliferation, which was effectively reversed by an overexpression of PINK1 in vitro. Through KEGG analysis and experimental validations, we discovered that Rosi reduced the expression of forkhead box protein O1 (FOXO1) which was a critical transcription factor of PINK1. Three FOXO1 consensus sequences (FCSs) were found in the first intron of the PINK1 gene, which could be potentially binding to FOXO1. The proximal FCS (chr 5: 156680169-156680185) from the translation start site exerted a more significant influence on PINK1 transcription than the other two FCSs. The overexpression of FOXO1 entirely relieved the inhibition of PINK1 transcription in the presence of Rosi.

CONCLUSIONS

Besides inflammation inhibition, Rosi suppressed mitophagy by reducing FOXO1 to decrease the transcription of PINK1, which played a pivotal role in accelerating the NSC proliferation.

Fabrication of hyaluronic acid-gold nanoparticles with chitosan to modulate neural differentiation of mesenchymal stem cells

BACKGROUND

Chitosan (Chi) is a natural material which has been widely used in neural applications due to possessing better biocompatibility. In this research study, a novel of nanocomposites film based on Chi with hyaluronic acid (HA), combined with varying amounts of gold nanoparticles (AuNPs), was created resulting in pure Chi, Chi-HA, Chi-HA-AuNPs (25 ppm), and Chi-HA-AuNPs (50 ppm).

METHODS

This study focused on evaluating their effects on mesenchymal stem cell (MSC) viability, colony formation, and biocompatibility. The surface morphology and chemical position were characterized through UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), SEM, and contact-angle assessment.

RESULTS

When seeding MSCs on Chi-HA-AuNPs (50 ppm), the results showed high cell viability, biocompatibility, and the highest colony formation ability. Meanwhile, the evidence showed that Chi-HA-Au nanofilm was able to inhibit nestin and β-tubulin expression of MSCs, as well as inhibit the ability of neurogenic differentiation. Furthermore, the results of matrix metalloproteinase 2/9 (MMP2/9) expression in MSCs were also significantly higher in the Chi-HA-AuNP (50 ppm) group, guiding with angiogenesis and wound healing abilities. In addition, in our rat model, both capsule thickness and collagen deposition were the lowest in Chi-HA-AuNPs (50 ppm).

CONCLUSION

Thus, in view of the in vitro and in vivo results, Chi-HA-AuNPs (50 ppm) could not only maintain the greatest stemness properties and regulate the neurogenic differentiation ability of MSCs, but was able to also induce the least immune response. Herein, Chi-HA-Au 50 ppm nanofilm holds promise as a suitable material for nerve regeneration engineering.