JOR Spine最新文献

Background: Low back pain (LBP) is predominantly caused by degeneration of the intervertebral disc (IVD) and central nucleus pulposus (NP) region. Conservative treatments fail to restore disc function, motivating the exploration of nucleic acid therapies, such as the use of microRNAs (miRNAs). miRNAs have the potential to modulate expression of discogenic factors, while silencing the catabolic cascade associated with degeneration. To deliver these miRNAs, nonviral cell penetrating peptides (CPPs) are gaining favor given their low immunogenicity and strong targeting ability. Single miRNA therapies have been investigated for IVD repair, however dual miRNA delivery strategies have not been commonly examined and may augment regeneration.

Materials and methods: Transfection of four pro-discogenic miRNAs (miRNA mimics:140-5p; 149-5p and inhibitors: 141-3p; 221-3p) and dual delivery of six miRNA pairings was performed using two CPPs, RALA and GET peptide (FLR), in primary rat NP monolayer culture, and in an ex vivo organ culture model of rat caudal discs. Protein expression of discogenic (aggrecan, collagen type II, and SOX9) and catabolic markers (ADAMTS5 and MMP13) were assessed.

Results: Monolayer investigations signified enhanced discogenic marker expression following dual miRNA delivery, signifying a synergistic effect when compared to single miRNA transfection. Utilization of an appropriate model was emphasized in our ex vivo organ culture experiment, revealing the establishment of a regenerative microenvironment characterized by reduced catabolic enzyme activity and enhanced matrix deposition, particularly following concurrent delivery of FLR-miRNA-149-5p mimic and miRNA-221-3p inhibitor. Bioinformatics analysis of miRNA-149-5p mimic and miRNA-221-3p inhibitor identified distinct targets, pathways, and interactions, suggesting a mode of action for this amplified response.

Conclusion: Our findings suggest the potential of FLR-miRNA-149-5p + miRNA-221-3p inhibitor to create an anti-catabolic niche within the disc to foster regeneration in moderate cases of disc degeneration, which could be utilized in further studies with the overarching aim of developing treatments for LBP.

Background: Spinal implant failure is associated with prolonged patient suffering, high costs for the medical device industry, and a high economic burden for the health care system. Pre-clinical mechanical testing has great potential to reduce the risk of such failure. However, there are no binding regulations for planning and interpretation of mechanical testing. Therefore, different strategies exist. Mainly for novel implants an option is to start with a structured scientific literature search that forms an objective background for the definition of an implant-specific test plan, the derivation of acceptance criteria and interpretation of the test results.

Methods: This paper describes, how a literature-based approach can look like from the initial literature search through the derivation of the test plan and the acceptance criteria, to the final test result evaluation and how this approach can support the proof that the device meets all necessary safety and performance standards.

Results: The main advantage of this literature-based approach is that testing and test result interpretation are linked with the loads acting on the individual implant in vivo. In an ideal case, testing is focused on the individual implant in a way that ensures maximum efficiency during the development and approval process combined with maximum insight in safety and effectiveness of the implant. Even comparative implant testing may become obsolete, which is a big advantage if comparative implant and related data are not available.

Conclusion: This approach to pre-clinical mechanical testing offers the potential to create a chain of arguments, from literature review through testing to the interpretation of test results. This methodology can significantly enhance testing efficiency, reduce risk of failure, and ultimately prevent unnecessary patient suffering and healthcare costs. By synthesizing scientific insights with regulatory requirements, this review aims to guide clinicians and researchers in improving patient care and advancing device technologies.

Background: Notochordal cells (NCs) present in the nucleus pulposus (NP) of the developing human intervertebral disc (IVD) disappear during the first decade of life. This loss coincides with the onset of IVD degeneration, therefore these cells are hypothesized to be important in NP homeostasis. Putative NC-derived (CD24⁺) and progenitor (TIE2⁺/GD2⁺) cell sub-populations have previously been identified in the adult human NP, but their characteristics have yet to be compared. Here, we used CD24, TIE2 and GD2 to identify and then isolate discrete cell sub-populations to assess cell phenotype.

Methods: CD24, GD2 and TIE2 positivity was assessed in a cohort of human pediatric and adult NP samples across a range of ages and histological degeneration grades using immunohistochemistry and flow cytometry. FACS sorting was used to isolate different cell sub-populations (CD24⁺/GD2⁺; CD24⁺/GD2^-; CD24^-/GD2⁺; CD24^-/GD2^-). Cell phenotype was assessed using qPCR for known NC and NP markers as well as catabolic genes.

Results: CD24⁺ and GD2⁺ cells were localized in all samples, irrespective of age or degeneration grade, while TIE2⁺ cell number was consistently very low. The same positivity trend was confirmed using flow cytometry. A small CD24⁺/GD2⁺ sub-population was present and maintained marker expression with time in culture. CD24⁺ subpopulations showed a significantly higher expression of NC markers than the CD24^- subpopulations and unsorted samples, suggesting a healthier phenotype in the CD24⁺ cells. GD2 did not appear to influence gene expression.

Conclusions: This study provides a better understanding of different cell sub-populations present in the adult NP, with identification of CD24⁺/GD2⁺ cells that are maintained with aging and degeneration. Healthy, NC-like phenotypic profiles appeared reliant on CD24, rather than GD2. The study highlights the importance of studying discrete cell sub-populations, especially CD24⁺ NP cells to better understand their role in NP homeostasis.

Chronic lower back pain is the leading cause of disability worldwide, generating a socioeconomic cost of over $100 billion annually in the United States. Among the prominent causes of low back pain (LBP) is degeneration of the intervertebral disk (IVD), a condition known as degenerative disk disease (DDD). Despite the prevalence of DDD and multiple studies demonstrating its relationship with LBP, the mechanisms by which it contributes to pain remain unknown. Previous studies have identified potential causes for this pain, such as extracellular matrix (ECM) breakdown, changes in biomechanics, and pro-inflammatory signals. Possible pain treatments targeting these factors have been developed but with limited effects. However, low pH in DDD is a potential pain generator whose role has largely been unexplored and underappreciated. This review highlights hyperacidity's effects on the IVD, such as catabolism of disk cells and ECM, neoinnervation, altered mechanical signaling, and expression of pro-inflammatory cytokines and ion channels. This review aims to discuss what is known about the contributions of acidity to DDD pain, identify the knowledge gaps on this topic, and propose what research can be conducted to fill these gaps. We must better understand the underlying mechanisms of DDD and the interaction between hyperacidity and nociception to develop better therapeutics for this disease.

Intervertebral disc degeneration (IVDD) stands as a prevalent chronic orthopedic ailment, profoundly impacting patients' well-being due to incapacitating low back pain. Studies have highlighted a close correlation between IVDD and the programmed cell death of nucleus pulposus (NP) cells orchestrated by interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and caspase-3 (CASP3). Puerarin, renowned for its anti-inflammatory attributes and its influence on IL-1β and TNF-α, emerges as a promising candidate for IVDD treatment. However, the precise mechanism by which it regulates apoptosis via these pathways remains ambiguous. This investigation utilizes bioinformatics to unveil the molecular intricacies of puerarin-mediated apoptosis regulation in IVDD, substantiated by preliminary in vitro experiments. Analysis exposes aberrant expression of pivotal apoptosis-associated proteins (IL-1β, TNF-α, CASP3, CASP8, and BCL2) in IVDD patients, with network pharmacology indicating puerarin's potential efficacy in IVDD treatment by modulating apoptosis and cellular senescence pathways. Further experiments elucidate puerarin's capacity to stimulate NP cell proliferation while inhibiting apoptosis, potentially contributing to IVDD mitigation. Western blot and PCR outcomes reveal escalated expression of apoptosis-related proteins (IL-1β, TNF-α, and CASP3) in lipopolysaccharide-treated NPCs, ameliorated by puerarin intervention. Molecular docking simulations demonstrate favorable binding properties of puerarin with apoptotic proteins, while flow cytometry analysis indicates its ability to diminish NPC apoptosis. These discoveries imply that puerarin might alleviate NPC apoptosis by modulating key targets, thereby potentially ameliorating IVDD. In summary, this study unveils the intrinsic mechanism of puerarin in regulating NPC apoptosis to alleviate IVDD, underscoring its therapeutic promise.