PTH1-34 inhibited TNF-α expression and antagonized TNF-α-induced MMP13 expression in MIO mice

This study aims to investigate the effects and mechanisms of parathyroid hormone [1-34] (PTH1-34) on TNF-α-stimulated mice chondrocytes, as well as cartilage from a meniscus injury induced osteoarthritis (MIO) mice model. The C57BL/6J mice received medial meniscectomy, and then administrated with PTH1-34. The results showed that PTH1-34 administration decreased secondary allodynia and the pain-related transcripts. The IHC, ELISA, Micro-CT imaging and histopathology analysis revealed the significantly improved subchondral plate thickness and bone porosity, the reduced pro-inflammatory cytokines in serum and joint fluid. In vitro, mice chondrocyte was treated with TNF-α or co-cultured with synovial cells. The results showed that TNF-α markedly upregulated the MMP13 expression, and the ERK1/2, NF-κB or PI3K signaling pathway inhibitors could reverse the induction effect of TNF-α on expression of MMP13 in chondrocytes. PTH1-34 alone has no effect on the expression of MMP13 and NF-κB signaling pathways, but the PTH1-34 could reverse the induction effect of TNF-α on MMP13 expression and NF-κB signaling pathway activation in chondrocytes. In addition, PTH1-34 administration inhibited the expression of TNF-α and MMP13, and chondrocyte viability, while the PKA repressor reversed the effect of PTH1-34 in chondrocytes co-cultured with synovial cells. In conclusion, PTH1-34 has an obvious analgesic and anti-inflammatory effect, inhibits the matrix synthesis and alleviates the progression of osteoarthritis. In vitro, PTH1-34 inhibited TNF-α expression and antagonized TNF-α-induced MMP13 expression via the PKA pathway and the NF-κB signaling pathways, respectively.

Engineering self-assembled neomenisci through combination of matrix augmentation and directional remodeling

Knee meniscus injury is frequent, resulting in over 1 million surgeries annually in the United States and Europe. Because of the near-avascularity of this fibrocartilaginous tissue and its intrinsic lack of healing, tissue engineering has been proposed as a solution for meniscus repair and replacement. This study describes an approach employing bioactive stimuli to enhance both extracellular matrix content and organization of neomenisci toward augmenting their mechanical properties. Self-assembled fibrocartilages were treated with TGF-β1, chondroitinase ABC, and lysyl oxidase-like 2 (collectively termed TCL) in addition to lysophosphatidic acid (LPA). TCL + LPA treatment synergistically improved circumferential tensile stiffness and strength, significantly enhanced collagen and pyridinoline crosslink content per dry weight, and achieved tensile anisotropy (circumferential/radial) values of neomenisci close to 4. This study utilizes a combination of bioactive stimuli for use in tissue engineering studies, providing a promising path toward deploying these neomenisci as functional repair and replacement tissues. STATEMENT OF SIGNIFICANCE: This study utilizes a scaffold-free approach, which strays from the tissue engineering paradigm of using scaffolds with cells and bioactive factors to engineer neotissue. While self-assembled neomenisci have attained compressive properties akin to native tissue, tensile properties still require improvement before being able to deploy engineered neomenisci as functional tissue repair or replacement options. In order to augment tensile properties, this study utilized bioactive factors known to augment matrix content in combination with a soluble factor that enhances matrix organization and anisotropy via cell traction forces. Using a bioactive factor to enhance matrix organization mitigates the need for bioreactors used to apply mechanical stimuli or scaffolds to induce proper fiber alignment.

Meniscus-Derived Matrix Bioscaffolds: Effects of Concentration and Cross-Linking on Meniscus Cellular Responses and Tissue Repair

Meniscal injuries, particularly in the avascular zone, have a low propensity for healing and are associated with the development of osteoarthritis. Current meniscal repair techniques are limited to specific tear types and have significant risk for failure. In previous work, we demonstrated the ability of meniscus-derived matrix (MDM) scaffolds to augment the integration and repair of an in vitro meniscus defect. The objective of this study was to determine the effects of percent composition and dehydrothermal (DHT) or genipin cross-linking of MDM bioscaffolds on primary meniscus cellular responses and integrative meniscus repair. In all scaffolds, the porous microenvironment allowed for exogenous cell infiltration and proliferation, as well as endogenous meniscus cell migration. The genipin cross-linked scaffolds promoted extracellular matrix (ECM) deposition and/or retention. The shear strength of integrative meniscus repair was improved with increasing percentages of MDM and genipin cross-linking. Overall, the 16% genipin cross-linked scaffolds were most effective at enhancing integrative meniscus repair. The ability of the genipin cross-linked scaffolds to attract endogenous meniscus cells, promote glycosaminoglycan and collagen deposition, and enhance integrative meniscus repair reveals that these MDM scaffolds are promising tools to augment meniscus healing.

Meniscus-Targeted Injections for Chronic Knee Pain Due to Meniscal Tears or Degenerative Fraying: A Retrospective Study

OBJECTIVES

Meniscal tears caused by acute trauma or degenerative fraying affect a wide array of individuals. An effective, long-lasting treatment has widely been sought after. Intra-articular corticosteroid injections have been among the methods of controlling pain for more than 60 years. However, such injections tend to produce short-lasting results, with profound effects lasting an average of up to 4 weeks. The purpose of this study was to determine the average duration and magnitude of pain relief after meniscal-targeted injections.

METHODS

The electronic medical records of 135 patients were accessed for this retrospective chart review. Patients who had meniscal tears or degenerative fraying and were treated with meniscal-targeted injections were selected. Patients' visual analog scale (VAS) pain scores (before and after treatment) were recorded, along with the percentage of pain relief and duration of pain relief.

RESULTS

Ultrasound-guided meniscus-targeted corticosteroid injections for meniscal tears or degenerative fraying produced 5.68 (SD, 5.28) weeks of pain relief on average, with a decrease in pain from initial to follow-up visits of 2.14 (P < .0001) as per the visual analog scale score, and an Integral of Pain Relief score of 3.98.

CONCLUSIONS

Our findings indicate a substantial benefit from 20- or 40-mg meniscus-targeted triamcinolone injections, granted the limitations of chart review research and no control group comparison. Results highlight the need for future prospective research comparing meniscus-targeted injections with intra-articular injections to identify a better modality for treating patients with chronic knee pain caused by meniscal tears or degenerative fraying.

Composite Double-Network Hydrogels To Improve Adhesion on Biological Surfaces

Despite the development of hydrogels with high mechanical properties, insufficient adhesion between these materials and biological surfaces significantly limits their use in the biomedical field. By controlling toughening processes, we designed a composite double-network hydrogel with ∼90% water content, which creates a dissipative interface and robustly adheres to soft tissues such as cartilage and meniscus. A double-network matrix composed of covalently cross-linked poly(ethylene glycol) dimethacrylate and ionically cross-linked alginate was reinforced with nanofibrillated cellulose. No tissue surface modification was needed to obtain high adhesion properties of the developed hydrogel. Instead, mechanistic principles were used to control interfacial crack propagation. Comparing to commercial tissue adhesives, the integration of the dissipative polymeric network on the soft tissue surfaces allowed a significant increase in the adhesion strength, such as ∼130 kPa for articular cartilage. Our findings highlight the significant role of controlling hydrogel structure and dissipation processes for toughening the interface. This research provides a promising path to the development of highly adhesive hydrogels for tissues repair.

A synthetic polymeric biolubricant imparts chondroprotection in a rat meniscal tear model

Intra-articular injection of hyaluronic acid (HA) is used to treat osteoarthritis (OA) as a viscosupplement, yet it only provides short-term benefit because HA is cleaved by hyaluronidase and cleared out of the joint after several days. Therefore, we developed a new polymer biolubricant based on poly-oxanorbornane carboxylate to enhance joint lubrication for a prolonged time. Rheological and biotribological studies of the biolubricant reveal viscoelastic properties and coefficient of friction equivalent and superior to that of healthy synovial fluid, respectively. Furthermore, in an ex vivo bovine cartilage plug model, the biolubricant exhibits superior long-term reduction of friction and wear prevention compared to saline and healthy synovial fluid. ISO 10993 biocompatibility tests demonstrate that the biolubricant polymer is non-toxic. In an in vivo rat medial meniscal tear OA model, where the performance of the leading HA viscosupplement (Synvisc-one®) is comparable to the saline control, treatment with the biolubricant affords significant chondroprotection compared to the saline control.

Effects of Anti-Inflammatory Agents on Expression of Early Responsive Inflammatory and Catabolic Genes in Ex Vivo Porcine Model of Acute Knee Cartilage Injury

Objective Early intervention therapies targeting inflammation and cell death during the acute phase of cartilage injury have the potential to prevent posttraumatic osteoarthritis. The objective of this study was to investigate the effects of interleukin receptor antagonist protein (IRAP), hyaluronan (HA), dexamethasone (DEX), and mesenchymal stem cell (MSC) treatment on the expression of established genetic markers for matrix degradation, apoptosis, and inflammation in articular cartilage during the acute phase of injury. Design A custom impact device was used to create replicable injury ex vivo to intact porcine knee joint. One hour after impact, IRAP, HA, DEX, or MSCs was intra-articularly injected. At 8 hours postinjury, cartilage and meniscus samples were harvested for genetic expression analysis. Expression of miR-27b, miR-140, miR-125b, miR-16, miR-34a, miR-146a, miR-22, ADAMTS-4, ADAMTS-5, MMP-3, IL-1β, and TNF-α was analyzed by real-time polymerase chain reaction. Results At 8 hours postinjury, expression of ADAMTS-4, ADAMTS-5, MMP-3, IL-1β, and TNF-α in cartilage was significantly decreased in IRAP- and DEX-treated joints as compared to nontreated injured joints, whereas only IRAP upregulated expression of miR-140, miR-125b, miR-27b, miR-146a, and miR-22 in cartilage. HA and MSC treatments had no significant effects on catabolic and inflammatory gene expression in cartilage. However, HA treatment significantly upregulated expression of all miRNAs except miR-16. In addition, the treatments tested also exhibited significant influences on meniscus. Conclusions This study provides a valuable starting point for further research into potential targets for and efficacy of various early intervention strategies that may delay or prevent the progression of posttraumatic osteoarthritis after acute cartilage injury.

Evaluation of articular disc loading in the temporomandibular joints after prosthetic and pharmacological treatment in model studies

BACKGROUND

Temporomandibular joint dysfunction is often related to excessive load in the stomatognathic system.

OBJECTIVES

The objective of the model tests, using numeric calculations, was to assess the articular disc loads in the temporomandibular joints after prosthetic and pharmacological treatment of functional disorders of the masticatory organ.

MATERIAL AND METHODS

The study involved 10 patients, aged 21-48 years, of both sexes, randomly selected from a group of 120 patients treated with relaxation occlusal splints (60 patients, group I) and intramuscular injection of botulinum toxin type A (60 patients, group II), suffering from temporomandibular joint dysfunction with the dominant muscle component. In all subjects, a specialized functional examination was carried out. Treatment groups: occlusal splint therapy (group I) and intramuscular injection of botulinum toxin type A (group II). An assessment of the loads of 4 disc zones of the temporomandibular joints was carried out based on the results of clinical studies (phase I of the study), and numeric model tests (phase II). In the representatives of the study groups (5 patients in each group), measurements of occlusal forces and an evaluation of tension of the masseter and temporalis muscle were performed.

RESULTS

The results of the average load values for all evaluated zones of the right and left articular disc differ in a statistically significant way in favor of group II, with the exception of the external mid part of the discs. In the case of the anterior of the right disc, the load was lower in patients belonging to group I than in those obtained in group II.

CONCLUSIONS

Botulinum toxin type A significantly reduces the loads within the temporomandibular joints, generated by masseter muscle hypertonia.

Selenium Reduces Early Signs of Tumor Necrosis Factor Alpha-Induced Meniscal Tissue Degradation

Meniscal integrity is a prerequisite for sustained knee joint health and prevention of meniscal degeneration is a main research goal. Cartilage-protective effects of selenium have been described, but little is known about the impact on the meniscus. We therefore investigated the influence of sodium selenite on meniscal explants under tumor necrosis factor-alpha (TNFα)-stimulated proinflammatory conditions. Meniscal explant disks (3 mm diameter × 1 mm thickness) were isolated from 2-year-old cattle and incubated with TNFα (10 ng/ml) and sodium selenite (low dose, LoD 6.7 ng/ml as being found in Insulin-Transferrin-Selenium medium supplements, ITS; medium-dose, MeD 40 ng/ml described as physiological synovial concentration; high dose, HiD 100 ng/ml described as optimal serum concentration). After 3 days of culture glycosaminoglycan (GAG) release (DMMB assay), nitric oxide (NO) production (Griess assay), gene expression of matrix-degrading enzymes (quantitative RT-PCR), and apoptosis rate were determined. TNFα led to a significant raise of GAG release and NO production. LoD and MeD selenite significantly reduced the TNFα-induced GAG release (by 83, 55 %, respectively), NO production (by 59, 40 %, respectively), and apoptosis (by 68, 39 %, respectively). LoD and MeD selenite showed a tendency to reduce the TNFα-mediated increase of inducible NO-synthase (iNOS) levels, LoD selenite furthermore matrix metalloproteinase (MMP)-3 transcription levels and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 levels. LoD and less pronounced MeD selenite show a substantial impact on the early meniscal inflammatory response. To our knowledge this is the first study showing the protective influence of selenium on meniscal tissue maintenance. To understand the superior potency of low-dose selenium on molecular level future studies are needed.