Vanillin-based functionalization strategy to construct multifunctional microspheres for treating inflammation and regenerating intervertebral disc

Rescuing Nucleus Pulposus Cells from ROS Toxic Microenvironment via Mitochondria-Targeted Carbon Dot-Supported Prussian Blue to Alleviate Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is invariably accompanied by excessive accumulation of reactive oxygen species (ROS), resulting in progressive deterioration of mitochondrial function and senescence in nucleus pulposus cells (NPCs). Significantly, the main ROS production site in non-immune cells is mitochondria, suggesting mitochondria is a feasible therapeutic target to reverse IVDD. Triphenylphosphine (TPP), which is known as mitochondrial-tropic ligands, is utilized to modify carbon dot-supported Prussian blue (CD-PB) to scavenge superfluous intro-cellular ROS and maintain NPCs at normal redox levels. CD-PB-TPP can effectively escape from lysosomal phagocytosis, permitting efficient mitochondrial targeting. After strikingly lessening the ROS in mitochondria via exerting antioxidant enzyme-like activities, such as superoxide dismutase, and catalase, CD-PB-TPP rescues damaged mitochondrial function and NPCs from senescence, catabolism, and inflammatory reaction in vitro. Imaging evaluation and tissue morphology assessment in vivo suggest that disc height index, mean grey values of nucleus pulposus tissue, and histological morphology are significantly improved in the IVDD model after CD-PB-TPP is locally performed. In conclusion, this study demonstrates that ROS-induced mitochondrial dysfunction and senescence of NPCs leads to IVDD and the CD-PB-TPP possesses enormous potential to rescue this pathological process through efficient removal of ROS via targeting mitochondria, supplying a neoteric strategy for IVDD treatment.

Reviving Intervertebral Discs: Treating Degeneration Using Advanced Delivery Systems

Intervertebral disc degeneration (IVDD) is commonly associated with many spinal problems, such as low back pain, and significantly impacts a patient's quality of life. However, current treatments for IVDD, which include conservative and surgical methods, are limited in their ability to fully address degeneration. To combat IVDD, delivery-system-based therapy has received extensive attention from researchers. These delivery systems can effectively deliver therapeutic agents for IVDD, overcoming the limitations of these agents, reducing leakage and increasing local concentration to inhibit IVDD or promote intervertebral disc (IVD) regeneration. This review first briefly introduces the structure and function of the IVD, and the related pathophysiology of IVDD. Subsequently, the roles of drug-based and bioactive-substance-based delivery systems in IVDD are highlighted. The former includes natural source drugs, nonsteroidal anti-inflammatory drugs, steroid medications, and other small molecular drugs. The latter includes chemokines, growth factors, interleukin, and platelet-rich plasma. Additionally, gene-based and cell-based delivery systems are briefly involved. Finally, the limitations and future development of the combination of therapeutic agents and delivery systems in the treatment of IVDD are discussed, providing insights for future research.

From drugs to biomaterials: a review of emerging therapeutic strategies for intervertebral disc inflammation

Chronic low back pain (LBP) is an increasingly prevalent issue, especially among aging populations. A major underlying cause of LBP is intervertebral disc degeneration (IDD), often triggered by intervertebral disc (IVD) inflammation. Inflammation of the IVD is divided into Septic and Aseptic inflammation. Conservative therapy and surgical treatment often fail to address the root cause of IDD. Recent advances in the treatment of IVD infection and inflammation range from antibiotics and small-molecule drugs to cellular therapies, biological agents, and innovative biomaterials. This review sheds light on the complex mechanisms of IVD inflammation and physiological and biochemical processes of IDD. Furthermore, it provides an overview of recent research developments in this area, intending to identify novel therapeutic targets and guide future clinical strategies for effectively treating IVD-related conditions.

Transplantation of active nucleus pulposus cells with a keep-charging hydrogel microsphere system to rescue intervertebral disc degeneration

BACKGROUND

Cell transplantation has been demonstrated as a promising approach in tissue regeneration. However, the reactive oxygen species (ROS) accumulation and inflammation condition establish a harsh microenvironment in degenerated tissue, which makes the transplanted cells difficult to survive.

METHODS

In this study, we constructed a keep-charging hydrogel microsphere system to enable cells actively proliferate and function in the degenerated intervertebral disc. Specifically, we combined Mg2+ to histidine-functionalized hyaluronic acid (HA-His-Mg2+) through coordination reaction, which was further intercrossed with GelMA to construct a double-network hydrogel microsphere (GelMA/HA-His-Mg2+, GHHM) with microfluidic methods. In vitro, the GHHM loaded with nucleus pulposus cells (GHHM@NPCs) was further tested for its ability to promote NPCs proliferation and anti-inflammatory properties. In vivo, the ability of GHHM@NPCs to promote regeneration of NP tissue and rescue intervertebral disc degeneration (IVDD) was evaluated by the rat intervertebral disc acupuncture model.

RESULTS

The GHHM significantly enhanced NPCs adhesion and proliferation, providing an ideal platform for the NPCs to grow on. The loaded NPCs were kept active in the degenerative intervertebral disc microenvironment as charged by the Mg2+ in GHHM microspheres to effectively support the loaded NPCs to reply against the ROS-induced inflammation and senescence. Moreover, we observed that GHHM@NPCs effectively alleviated nucleus pulposus degeneration and promoted its regeneration in the rat IVDD model.

CONCLUSION

In conclusion, we constructed a keep charging system with a double-network hydrogel microsphere as a framework and Mg2+ as a cell activity enhancer, which effectively maintains NPCs active to fight against the harsh microenvironment in the degenerative intervertebral disc. The GHHM@NPCs system provides a promising approach for IVDD management.

Enhanced Mitochondrial Targeting and Inhibition of Pyroptosis with Multifunctional Metallopolyphenol Nanoparticles in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a significant contributor to low back pain, characterized by excessive reactive oxygen species generation and inflammation-induced pyroptosis. Unfortunately, there are currently no specific molecules or materials available to effectively delay IVDD. This study develops a multifunctional full name of PG@Cu nanoparticle network (PG@Cu). A designed pentapeptide, bonded on PG@Cu nanoparticles via a Schiff base bond, imparts multifunctionality to the metal polyphenol particles (PG@Cu-FP). PG@Cu-FP exhibits enhanced escape from lysosomal capture, enabling efficient targeting of mitochondria to scavenge excess reactive oxygen species. The scavenging activity against reactive oxygen species originates from the polyphenol-based structures within the nanoparticles. Furthermore, Pyroptosis is effectively blocked by inhibiting Gasdermin mediated pore formation and membrane rupture. PG@Cu-FP successfully reduces the activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome by inhibiting Gasdermin protein family (Gasdermin D, GSDMD) oligomerization, leading to reduced expression of Nod-like receptors. This multifaceted approach demonstrates higher efficiency in inhibiting Pyroptosis. Experimental results confirm that PG@Cu-FP preserves disc height, retains water content, and preserves tissue structure. These findings highlight the potential of PG@Cu-FP in improving IVDD and provide novel insights for future research in IVDD treatments.

Green chemistry production of biopolymeric film-derived biomaterial prepared using natural alginate and vanillin compounds for application as a biocurative

The present work presents the results obtained in the production of vanillin-doped alginate biopolymeric film using green chemistry methodology. Alginate dressings are already a therapeutic reality, but they act only by maintaining the appropriate environment for healing. In order to improve their properties, the incorporation of vanillin was proposed due to its antioxidant and antimicrobial potential. Different biopolymeric films were produced employing the experiment planning through response surface analysis, which allowed determining the best region for a medium value of solubility and high degree of swelling. This region refers to values above 0.07 g of CaCl2 and concentrations above 0.024 g of vanillin, triggering solubility between 25 and 30% and a degree of swelling above 100% and with fixed values of alginate (0.85 g). Such data are related to experiments (A), (B), and (C) listed in Table 1. Regarding the optimization of the process, the normal boundary intersection (NBI) method allowed the analysis of concave regions, predicting the optimal points and generating the Pareto chart with equidistant limits. The antimicrobial test allowed observing the antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa microorganisms from the biopolymeric films, as well as a solution of vanillin with calcium chloride and glycerol obtaining a halo of inhibition only in the presence of vanillin, and there was no significant difference between the results obtained in the experiments (A) and (B). The thermal analyses showed that the material has thermal stability in the ideal temperature range (~ 25 °C) for application as a biocurative. We preliminarily concluded that the alginate biopolymeric film doped with vanillin prepared using green chemical methodology presents antimicrobial properties and thermal stability that indicate its potential use as biocurative.