Current Knowledge and Future Therapeutic Prospects in Symptomatic Intervertebral Disc Degeneration

Integrating metabolomics and network pharmacology to study the mechanism of Er-Xian decoction in improving intervertebral disc degeneration

ETHNOPHARMACOLOGICAL RELEVANCE

Intervertebral disc degeneration (IDD) is the progressive deterioration of the structure and function of an intervertebral disc (IVD), which manifests as excessive catabolism of the IVD extracellular matrix, which may lead to the gradual loss of IVD proteoglycans and water, thus altering the IVD composition and eventually leading to degeneration. As a traditional Chinese medicine, Er-Xian decoction (EXD) can balance the body's yin and yang, tonify the liver and kidney, invigorate blood circulation, and prevent blood stasis. Pharmacological research has shown that EXD regulates antioxidant and endocrine metabolism, maintains immune balance, and improves microcirculation.

AIMS OF THE STUDY

To clarify the efficacy of EXD on treating IDD.

MATERIALS AND METHODS

Serum was collected from model IDD rabbits treated with EXD for metabolomics analysis, and its mechanism of action was predicted on the basis of the metabolomics and network pharmacology data. Nucleus pulposus cells (NPCs) were induced with IL-1β to build an in vitro IDD model, and EXD was administered along with an inhibitor. All groups of cells were subjected to CCK-8 assays, ELISA and flow cytometry, immunohistochemistry, Western blot, and immunofluorescence staining analyses to explore how EXD protects NPCs and the underlying mechanism.

RESULTS

EXD reduced inflammatory processes, restored IVD height, and alleviated IDD in rabbits. Integrated metabolomics and network pharmacology analyses revealed that EXD exerts its therapeutic effects on IDD primarily via the mTOR and HIF-1 signalling pathways, and the active components of EXD, including anhydroicaritin, β-sitosterol, kaempferol, quercetin, and stigmasterol, bound strongly to pivotal targets within these pathways. Moreover, EXD reduced the inflammatory factor levels, inhibited NPC apoptosis, and upregulated the key proteins p-mTOR, HIF-1α, and p-AKT. Conversely, the HIF-1 inhibitor BAY872243 increased the inflammatory factor levels and led to NPC deterioration.

CONCLUSION

EXD regulates disc cell metabolism and inflammatory responses by modulating the mTOR and HIF-1 signalling pathways, thereby slowing or reversing IDD.

Neuroinflammation and nociception in intervertebral disc degeneration: a review of precision medicine perspective

Intervertebral disc (IVD) degeneration is a major cause of low back pain (LBP), which results in disability worldwide. However, the pathogenesis of IVD degeneration mediating LBP remains unclear. Current conservative treatments and surgical interventions are both to relieve the symptoms and minimise pain; nevertheless, they are unable to reverse the degeneration. Previous studies have shown that inflammation and nociception markers are important indicators of pain mechanisms in IVD degeneration underlying LBP. As such, multiomics profiling allows the discovery of these target markers to understand the key pathological mechanisms mediating IVD degeneration underpinnings of LBP. This article provides insights into a precision medicine approach for identifying and understanding the pathophysiology of IVD degeneration associated with LPB based on the severity of the disease from early and mild to severe degenerative stages. Molecular profiling of key markers in degenerative IVDs based on patient stratification at early, mild, and severe stages will contribute to the identification of target markers associated with signalling pathways in mediating neuroinflammation, innervation, and nociception underlying painful IVD degeneration. This approach will offer an understanding of establishing personalised clinical strategies tailored to the severity of IVD degeneration for the treatment of LBP.

Prospective study on a new combination of pulsed radiofrequency and platelet-rich plasma injections for managing grade I lumbosacral spondylolisthesis

Our study aimed to investigate the clinical benefits of combining pulsed radiofrequency (PRF) and platelet-rich plasma (PRP) techniques for treating chronic lumbosacral radicular (CLSR) pain resulting from grade I spondylolisthesis (G1SL). Ninety-six patients with CLSR pain between March 2021 and March 2023 were included in this study, 58 patients with G1SL without instability on dynamic radiographs - Group A and 38 patients with instability - Group B. Pre-procedure, Group B had higher pain levels than Group A. Post-procedure and at follow-up intervals, Visual Analog Scale (VAS) pain scores improved in both groups (p < 0.05) and there were no significant differences between the groups. Both groups also showed significant improvement in ODI scores post-procedure, which was maintained at follow-up intervals. The treatment effect, evaluated using the modified MacNab criteria, showed high rates of excellent and good outcomes in both groups, with no significant differences. Importantly, no patients experienced severe complications or required open surgery during the 6-month follow-up. Based on these findings, a new treatment combining PRF and PRP applications appears beneficial in managing pain in regenerative medicine. So, further clinical studies are necessary to support and validate our preliminary findings.

The Role of Microvascular Variations in the Process of Intervertebral Disk Degeneration and Its Regulatory Mechanisms: A Literature Review

Microvascular changes are considered key factors in the process of intervertebral disk degeneration (IDD). Microvascular invasion and growth into the nucleus pulposus (NP) and cartilaginous endplates are unfavorable factors that trigger IDD. In contrast, the rich distribution of microvessels in the bony endplates and outer layers of the annulus fibrosus is an important safeguard for the nutrient supply and metabolism of the intervertebral disk (IVD). In particular, the adequate supply of microvessels in the bony endplates is the main source of the nutritional supply for the entire IVD. Microvessels can affect the progression of IDD through a variety of pathways. Many studies have explored the effects of microvessel alterations in the NP, annulus fibrosus, cartilaginous endplates, and bony endplates on the local microenvironment through inflammation, apoptosis, and senescence. Studies also elucidated the important roles of microvessel alterations in the process of IDD, as well as conducted in-depth explorations of cytokines and biologics that can inhibit or promote the ingrowth of microvessels. Therefore, the present manuscript reviews the published literature on the effects of microvascular changes on IVD to summarize the roles of microvessels in IVD and elaborate on the mechanisms of action that promote or inhibit de novo microvessel formation in IVD.

"Dictionary of immune responses" reveals the critical role of monocytes and the core target IRF7 in intervertebral disc degeneration

Background

Intervertebral disc degeneration (IDD) is widely regarded as the primary contributor to low back pain(LBP). As an immune-privileged organ, upon the onset of IDD, various components of the nucleus pulposus (NP) are exposed to the host's immune system, accumulating cytokines. Cytokines facilitate intercellular communication within the immune system, induce immune cells polarisation, and exacerbate oxidative stress in IDD.

Methods

Machine learning was used to identify crucial immune cells. Subsequently, Immune Response Enrichment Analysis (IREA) was conducted on the key immune cells to determine their cytokine responses and polarisation states in IDD. "CellChat" package facilitated the analysis of cell-cell communication. Differential gene expression analysis, PPI network, GO and KEGG pathway enrichment analysis, GSVA, co-expressed gene analysis and key gene-related networks were also performed to explore hub genes and their associated functions. Lastly, the differential expression and functions of key genes were validated through in vitro and in vivo experiments.

Results

Through multiple machine learning methods, monocytes were identified as the crucial immune cells in IDD, exhibiting significant differentiation capacity. IREA revealed that monocytes in IDD polarize into an IFN-a1 and IFN-b enriched Mono-a state, potentially intensifying inflammation. Cell-cell communication analysis uncovered alteration in ANNEXIN pathway and a reduction in CXCL signaling between macrophages and monocytes, suggesting immune response dysregulation. Furthermore, ten algorithms identified three hub genes. Both experiments conducted in vitro and in vivo have conclusively shown that IRF7 serves as a crucial target for the treatment of IDD, and its knockdown alleviates IDD. Eight small-molecule drugs were predicted to have therapeutic potential for IDD.

Conclusion

These findings offer a multidimensional understanding of the pathogenesis of IDD, pinpointing monocytes and key genes as potential diagnostic and therapeutic targets. They provide novel insights into potential diagnostic and therapeutic targets for IDD.

Banked Primary Progenitor Cells for Allogeneic Intervertebral Disc (IVD) Therapy: Preclinical Qualification and Functional Optimization within a Cell Spheroid Formulation Process

Background/Objectives: Biological products are emerging as therapeutic management options for intervertebral disc (IVD) degenerative affections and lower back pain. Autologous and allogeneic cell therapy protocols have been clinically implemented for IVD repair. Therein, several manufacturing process design considerations were shown to significantly influence clinical outcomes. The primary objective of this study was to preclinically qualify (chondrogenic potential, safety, resistance to hypoxic and inflammatory stimuli) cryopreserved primary progenitor cells (clinical grade FE002-Disc cells) as a potential cell source in IVD repair/regeneration. The secondary objective of this study was to assess the cell source's delivery potential as cell spheroids (optimization of culture conditions, potential storage solutions). Methods/Results: Safety (soft agar transformation, β-galactosidase, telomerase activity) and functionality-related assays (hypoxic and inflammatory challenge) confirmed that the investigated cellular active substance was highly sustainable in defined cell banking workflows, despite possessing a finite in vitro lifespan. Functionality-related assays confirmed that the retained manufacturing process yielded strong collagen II and glycosaminoglycan (GAG) synthesis in the spheroids in 3-week chondrogenic induction. Then, the impacts of various process parameters (induction medium composition, hypoxic incubation, terminal spheroid lyophilization) were studied to gain insights on their criticality. Finally, an optimal set of technical specifications (use of 10 nM dexamethasone for chondrogenic induction, 2% O2 incubation of spheroids) was set forth, based on specific fine tuning of finished product critical functional attributes. Conclusions: Generally, this study qualified the considered FE002-Disc progenitor cell source for further preclinical investigation based on safety, quality, and functionality datasets. The novelty and significance of this study resided in the establishment of defined processes for preparing fresh, off-the-freezer, or off-the-shelf IVD spheroids using a preclinically qualified allogeneic human cell source. Overall, this study underscored the importance of using robust product components and optimal manufacturing process variants for maximization of finished cell-based formulation quality attributes.

Repair of annulus fibrosus defects using decellularized annulus fibrosus matrix/chitosan hybrid hydrogels

Degenerative disc disease is the leading cause of lower back and leg pain, considerably impacting daily life and incurring substantial medical expenses for those affected. The development of annulus fibrosus tissue engineering offers hope for treating this condition. However, the current annulus fibrosus tissue engineering scaffolds fail to accurately mimic the natural biological environment of the annulus fibrosus, resulting in limited secretion of extracellular matrix produced by the seeded cells and poor biomechanical properties of the constructed biomimetic annulus fibrosus tissue. This inability to match the biomechanical performance of the natural annulus fibrosus hinders the successful treatment of annulus fibrosus defects. In this study, we fabricated decellularized annulus fibrosus matrix (DAFM)/chitosan hydrogel-1 (DAFM: Chitosan 6:2) and DAFM/chitosan hydrogel-2 (DAFM: Chitosan 4:4) by varying the ratio of DAFM to chitosan. Rat annulus fibrosus (AF)-derived stem cells were cultured on these hydrogel scaffolds, and the cell morphology, AF-related gene expression, and Interleukin-6 (IL-6) levels were investigated. Additionally, magnetic resonance imaging, Hematoxylin and eosin staining, and Safranine and Fast Green staining were performed to evaluate the repair effect of the DAFM/chitosan hydrogels in vivo. The gene expression results showed that the expression of Collagen type I (Col-I), Collagen type I (Col-II), and aggrecan by annulus fibrosus stem cells (AFSCs) cultured on the DAFM/chitosan-1 hydrogel was higher compared with the DAFM/chitosan-2 hydrogel. Conversely, the expression of metalloproteinase-9 (MMP-9) and IL-6 was lower on the DAFM/chitosan-1 hydrogel compared with the DAFM/chitosan-2 hydrogel. In vivo, both the DAFM/chitosan-1 and DAFM/chitosan-2 hydrogels could partially repair large defects of the annulus fibrosus in rat tail vertebrae. In conclusion, the DAFM/chitosan-1 hydrogel could be regarded as a candidate scaffold material for the repair of annulus fibrosus defects, offering the potential for improved treatment outcomes.

Injectable, self-healing hydrogels based on gelatin, quaternized chitosan, and laponite as localized celecoxib delivery system for nucleus pulpous repair

Utilization of injectable hydrogels stands as a paradigm of minimally invasive intervention in the context of intervertebral disc degeneration treatment. Restoration of nucleus pulposus (NP) function exerts a profound influence in alleviating back pain. This study introduces an innovative class of injectable shear-thinning hydrogels, founded on quaternized chitosan (QCS), gelatin (GEL), and laponite (LAP) with the capacity for sustained release of the anti-inflammatory drug, celecoxib (CLX). First, synthesis of Magnesium-Aluminum-Layered double hydroxide (LDH) was achieved through a co-precipitation methodology, as a carrier for celecoxib and a source of Mg ions. Intercalation of celecoxib within LDH layers (LDH-CLX) was verified through a battery of analytical techniques, including FTIR, XRD, SEM, EDAX, TGA and UV-visible spectroscopy confirmed a drug loading efficiency of 39.22 ± 0.09 % within LDH. Then, LDH-CLX was loaded in the optimal GEL-QCS-LAP hydrogel under physiological conditions. Release behavior (15 days profile), mechanical properties, swelling ratio, and degradation rate of the resulting composite were evaluated. A G* of 15-47 kPa was recorded for the hydrogel at 22-40 °C, indicating gel stability in this temperature range. Self-healing properties and injectability of the composite were proved by rheological measurements. Also, ex vivo injection into intervertebral disc of sheep, evidenced in situ forming and NP cavity filling behavior of the hydrogel. Support of GEL-QCS-LAP/LDH-CLX (containing mg2+ ions) for viability and proliferation (from ~94 % on day 1 to ~134 % on day 7) of NP cells proved using MTT assay, DAPI and Live/Dead assays. The hydrogel could significantly upregulate secretion of glycosaminoglycan (GAG, from 4.68 ± 0.1 to 27.54 ± 1.0 μg/ml), when LHD-CLX3% was loaded. We conclude that presence of mg2+ ion and celecoxib in the hydrogel can lead to creation of a suitable environment that encourages GAG secretion. In conclusion, the formulated hydrogel holds promise as a minimally invasive candidate for degenerative disc repair.

Activated Leukocyte Cell Adhesion Molecule Regulates the Expression of Interleukin-33 in RSV Induced Airway Inflammation by Regulating MAPK Signaling Pathways

PURPOSE

The respiratory syncytial virus (RSV) is a common respiratory virus that causes acute lower respiratory tract infectious diseases, particularly in young children and older individuals. Activated leukocyte cell adhesion molecule (ALCAM) is a membrane glycoprotein expressed in various cell types, including epithelial cells, and is associated with inflammatory responses and various cancers. However, the precise role of ALCAM in RSV-induced airway inflammation remains unclear, and our study aimed to explore this gap in the literature.

METHODS

C57BL/6 wild-type, ALCAM knockout mice and airway epithelial cells were infected with RSV and the expression of ALCAM and inflammatory cytokines were measured. We also conducted further experiments using Anti-ALCAM antibody and recombinant ALCAM in airway epithelial cells.

RESULTS

The expression levels of ALCAM and inflammatory cytokines increased in both RSV-infected mice and airway epithelial cells. Interestingly, IL-33 expression was significantly reduced in ALCAM-knockdown cells compared to control cells following RSV infection. Anti-ALCAM antibody treatment also reduced IL-33 expression following RSV infection. Furthermore, the phosphorylation of ERK1/2, p38, and JNK was diminished in ALCAM-knockdown cells compared to control cells following RSV infection. Notably, in the control cells, inhibition of these pathways significantly decreased the expression of IL-33. In vivo study also confirmed a reduction in inflammation induced by RSV infection in ALCAM deficient mice compared to wild-type mice.

CONCLUSION

These findings demonstrate that ALCAM contributes to RSV-induced airway inflammation at least partly by influencing IL-33 expression through mitogen-activated protein kinase signaling pathways. These results suggest that targeting ALCAM could be a potential therapeutic strategy for alleviating IL-33-associated lung diseases.

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.

Application and development of hydrogel biomaterials for the treatment of intervertebral disc degeneration: a literature review

Low back pain caused by disc herniation and spinal stenosis imposes an enormous medical burden on society due to its high prevalence and refractory nature. This is mainly due to the long-term inflammation and degradation of the extracellular matrix in the process of intervertebral disc degeneration (IVDD), which manifests as loss of water in the nucleus pulposus (NP) and the formation of fibrous disc fissures. Biomaterial repair strategies involving hydrogels play an important role in the treatment of intervertebral disc degeneration. Excellent biocompatibility, tunable mechanical properties, easy modification, injectability, and the ability to encapsulate drugs, cells, genes, etc. make hydrogels good candidates as scaffolds and cell/drug carriers for treating NP degeneration and other aspects of IVDD. This review first briefly describes the anatomy, pathology, and current treatments of IVDD, and then introduces different types of hydrogels and addresses "smart hydrogels". Finally, we discuss the feasibility and prospects of using hydrogels to treat IVDD.

Inducing Angiogenesis in the Nucleus Pulposus

Bone morphogenetic protein (BMP) gene delivery to Lewis rat lumbar intervertebral discs (IVDs) drives bone formation anterior and external to the IVD, suggesting the IVD is inhospitable to osteogenesis. This study was designed to determine if IVD destruction with a proteoglycanase, and/or generating an IVD blood supply by gene delivery of an angiogenic growth factor, could render the IVD permissive to intra-discal BMP-driven osteogenesis and fusion. Surgical intra-discal delivery of naïve or gene-programmed cells (BMP2/BMP7 co-expressing or VEGF165 expressing) +/- purified chondroitinase-ABC (chABC) in all permutations was performed between lumbar 4/5 and L5/6 vertebrae, and radiographic, histology, and biomechanics endpoints were collected. Follow-up anti-sFlt Western blotting was performed. BMP and VEGF/BMP treatments had the highest stiffness, bone production and fusion. Bone was induced anterior to the IVD, and was not intra-discal from any treatment. chABC impaired BMP-driven osteogenesis, decreased histological staining for IVD proteoglycans, and made the IVD permissive to angiogenesis. A soluble fragment of VEGF Receptor-1 (sFlt) was liberated from the IVD matrix by incubation with chABC, suggesting dysregulation of the sFlt matrix attachment is a possible mechanism for the chABC-mediated IVD angiogenesis we observed. Based on these results, the IVD can be manipulated to foster vascular invasion, and by extension, possibly osteogenesis.

Effectiveness of Toothbrushing Technique for Biofilm Removal and Postoperative Infection Control after Spinal Fusion Surgery: A Retrospective Study

This retrospective study was designed to investigate the effectiveness of using a toothbrush, which is commonly used in our daily life, for biofilm removal and infection control in the treatment of spinal infections occurring after spinal fusion surgery. Currently, a biofilm is thought to form on the surface of the metal inserted during spine fusion surgery. We aim to determine the differences in clinical outcomes between using and not using a toothbrush to remove biofilm while performing conventional drainage, curettage, and debridement. A total of 1081 patients who underwent anterior or posterior spinal fusion surgery between November 2018 and October 2022 were screened. The study included 60 patients who developed surgical site infection and underwent incision and drainage surgery either with a toothbrush (n = 20) or without a toothbrush (n = 40). Failure of infection control that requires revision surgery occurred in 2 patients (10%) in the Toothbrush group and in 14 patients (35%) in the No-Toothbrush group (p = 0.039). Thus, the rate of additional surgery was significantly lower in the Toothbrush group. Additionally, normalization of c-reactive protein levels occurred significantly faster in the Toothbrush group (p = 0.044). Therefore, using a toothbrush to treat spinal infections following spinal fusion surgery appears to have beneficial mechanical debridement effects, resulting in improved clinical results, which were also confirmed based on the electron microscopic images.

GREM1, LRPPRC and SLC39A4 as potential biomarkers of intervertebral disc degeneration: a bioinformatics analysis based on multiple microarray and single-cell sequencing data

BACKGROUND

Low back pain (LBP) has drawn much widespread attention and is a major global health concern. In this field, intervertebral disc degeneration (IVDD) is frequently the focus of classic studies. However, the mechanistic foundation of IVDD is unclear and has led to conflicting outcomes.

METHODS

Gene expression profiles (GSE34095, GSE147383) of IVDD patients alongside control groups were analyzed to identify differentially expressed genes (DEGs) in the GEO database. GSE23130 and GSE70362 were applied to validate the yielded key genes from DEGs by means of a best subset selection regression. Four machine-learning models were established to assess their predictive ability. Single-sample gene set enrichment analysis (ssGSEA) was used to profile the correlation between overall immune infiltration levels with Thompson grades and key genes. The upstream targeting miRNAs of key genes (GSE63492) were also analyzed. A single-cell transcriptome sequencing data (GSE160756) was used to define several cell clusters of nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous endplate (CEP) of human intervertebral discs and the distribution of key genes in different cell clusters was yielded.

RESULTS

By developing appropriate p-values and logFC values, a total of 6 DEGs was obtained. 3 key genes (LRPPRC, GREM1, and SLC39A4) were validated by an externally validated predictive modeling method. The ssGSEA results indicated that key genes were correlated with the infiltration abundance of multiple immune cells, such as dendritic cells and macrophages. Accordingly, these 4 key miRNAs (miR-103a-3p, miR-484, miR-665, miR-107) were identified as upstream regulators targeting key genes using the miRNet database and external GEO datasets. Finally, the spatial distribution of key genes in AF, CEP, and NP was plotted. Pseudo-time series and GSEA analysis indicated that the expression level of GREM1 and the differentiation trajectory of NP chondrocytes are generally consistent. GREM1 may mainly exacerbate the degeneration of NP cells in IVDD.

CONCLUSIONS

Our study gives a novel perspective for identifying reliable and effective gene therapy targets in IVDD.

High-Tech Methods of Cytokine Imbalance Correction in Intervertebral Disc Degeneration

An important mechanism for the development of intervertebral disc degeneration (IDD) is an imbalance between anti-inflammatory and pro-inflammatory cytokines. Therapeutic and non-therapeutic approaches for cytokine imbalance correction in IDD either do not give the expected result, or give a short period of time. This explains the relevance of high-tech medical care, which is part of specialized care and includes the use of new resource-intensive methods of treatment with proven effectiveness. The aim of the review is to update knowledge about new high-tech methods based on cytokine imbalance correction in IDD. It demonstrates promise of new approaches to IDD management in patients resistant to previously used therapies, including: cell therapy (stem cell implantation, implantation of autologous cultured cells, and tissue engineering); genetic technologies (gene modifications, microRNA, and molecular inducers of IDD); technologies for influencing the inflammatory cascade in intervertebral discs mediated by abnormal activation of inflammasomes; senolytics; exosomal therapy; and other factors (hypoxia-induced factors; lysyl oxidase; corticostatin; etc.).

Low back pain and osteoarthritis pain: a perspective of estrogen

Low back pain (LBP) is the world's leading cause of disability and is increasing in prevalence more rapidly than any other pain condition. Intervertebral disc (IVD) degeneration and facet joint osteoarthritis (FJOA) are two common causes of LBP, and both occur more frequently in elderly women than in other populations. Moreover, osteoarthritis (OA) and OA pain, regardless of the joint, are experienced by up to twice as many women as men, and this difference is amplified during menopause. Changes in estrogen may be an important contributor to these pain states. Receptors for estrogen have been found within IVD tissue and nearby joints, highlighting the potential roles of estrogen within and surrounding the IVDs and joints. In addition, estrogen supplementation has been shown to be effective at ameliorating IVD degeneration and OA progression, indicating its potential use as a therapeutic agent for people with LBP and OA pain. This review comprehensively examines the relationship between estrogen and these pain conditions by summarizing recent preclinical and clinical findings. The potential molecular mechanisms by which estrogen may relieve LBP associated with IVD degeneration and FJOA and OA pain are discussed.

Molecular Basic of Pharmacotherapy of Cytokine Imbalance as a Component of Intervertebral Disc Degeneration Treatment

Intervertebral disc degeneration (IDD) and associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. With age, IDD progresses, leading to spondylosis, spondylarthrosis, herniated disc, spinal canal stenosis. One of the leading mechanisms in the development of IDD and chronic back pain is an imbalance between pro-inflammatory and anti-inflammatory cytokines. However, classical therapeutic strategies for correcting cytokine imbalance in IDD do not give the expected response in more than half of the cases. The purpose of this review is to update knowledge about new and promising therapeutic strategies based on the correction of the molecular mechanisms of cytokine imbalance in patients with IDD. This review demonstrates that knowledge of the molecular mechanisms of the imbalance between pro-inflammatory and anti-inflammatory cytokines may be a new key to finding more effective drugs for the treatment of IDD in the setting of acute and chronic inflammation.

Significance of Immune-Related Genes in the Diagnosis and Classification of Intervertebral Disc Degeneration

Background

With the extensive development of intervertebral disc degeneration (IDD) research, IDD has been found to be a complex disease associated with immune-related gene (IRGs) changes. Nonetheless, the roles of IRGs in IDD are unclear.

Methods

In our study, 11 IRGs were chosen using differential analysis between nondisc degeneration and degenerative patients from the GEO database. Then, we utilized a random forest (RF) model to screen six candidate IRGs to predict the risk of IDD. A nomogram was developed on the basis of six candidate IRGs, and DCA showed that patients could benefit from the nomogram. Based on the selected significant IRGs, a consensus clustering approach was used to differentiate disc degeneration patients into two immune patterns (immune cluster A and B). The PCA algorithm was constructed to compute immune scores for every sample, to quantify immune patterns. The immune scores of immune cluster B patients were higher than those of immune cluster A.

Results

Through differential expression analysis between healthy and IDD samples, 11 significant IRGs (CTSS, S100Z, STAT3, KLRK1, FPR1, C5AR2, RLN1, IFGR2, IL2RB, IL17RA, and IL6R) were recognized through significant IRGs. The “Reverse Cumulative Distribution of Residual” and “Boxplots of Residual” indicate that the RF model has minimal residuals. The majority of samples in the model have relatively small residuals, demonstrating that the model is better. Besides, the nomogram model was constructed based on importance and the IRGs with importance scores greater than 2 (FPR1, RLN1, S100Z, IFNGR2, KLRK1, and CTSS). The nomogram model revealed that decision-making based on an established model might be beneficial for IDD patients, and the predictive power of the nomogram model was significant. In addition, we identified two different immune cluster patterns (immune cluster A and immune cluster B) based on the 11 IRGs. We found that immune cluster A had significantly higher levels of MDSC, neutrophil, plasmacytoid dendritic cell, and type 17 T helper cell expression than immune cluster B. And we calculated the score for each sample to quantify the gene patterns. The patients in immune cluster B or gene cluster B had higher immune scores than those in immune cluster A or gene cluster A.

Conclusion

In conclusion, IRGs play an extremely significant role in the occurrence of IDD. Our study of immune patterns may guide the strategies of prevention and treatment for IDD in the future.

Aggressive strategies for regenerating intervertebral discs: stimulus-responsive composite hydrogels from single to multiscale delivery systems

As our research on the physiopathology of intervertebral disc degeneration (IVD degeneration, IVDD) has advanced and tissue engineering has rapidly evolved, cell-, biomolecule- and nucleic acid-based hydrogel grafting strategies have been widely investigated for their ability to overcome the harsh microenvironment of IVDD. However, such single delivery systems suffer from excessive external dimensions, difficult performance control, the need for surgical implantation, and difficulty in eliminating degradation products. Stimulus-responsive composite hydrogels have good biocompatibility and controllable mechanical properties and can undergo solution-gel phase transition under certain conditions. Their combination with ready-to-use particles to form a multiscale delivery system may be a breakthrough for regenerative IVD strategies. In this paper, we focus on summarizing the progress of research on the stimulus response mechanisms of regenerative IVD-related biomaterials and their design as macro-, micro- and nanoparticles. Finally, we discuss multi-scale delivery systems as bioinks for bio-3D printing technology for customizing personalized artificial IVDs, which promises to take IVD regenerative strategies to new heights.