Weekly injections of Hylan G-F 20 delay cartilage degeneration in partial meniscectomized rat knees

The Therapeutic Potential of Exosomes vs. Matrix-Bound Nanovesicles from Human Umbilical Cord Mesenchymal Stromal Cells in Osteoarthritis Treatment

Osteoarthritis (OA) is a degenerative joint disease with limited therapeutic options, where inflammation plays a critical role in disease progression. Extracellular vesicles (EV) derived from mesenchymal stromal cells (MSC) have shown potential as a therapeutic approach for OA by modulating inflammation and alleviating degenerative processes in the joint. This study evaluated the therapeutic effects for the treatment of OA of two types of EV-exosomes and matrix-bound nanovesicles (MBV)-both derived from the human umbilical cord MSC (UC-MSC) via differential ultracentrifugation. Different phenotypes of human monocyte-derived macrophages (MDM) were used to study the anti-inflammatory properties of EV in vitro, and the medial meniscectomy-induced rat model of knee osteoarthritis (MMx) was used in vivo. The study found that both EV reduced pro-inflammatory cytokines IL-6 and TNF-α in MDM. However, exosomes showed superior results, preserving the extracellular matrix (ECM) of hyaline cartilage, and reducing synovitis more effectively than MBVs. Additionally, exosomes downregulated inflammatory markers (TNF-α, iNOS) and increased Arg-1 expression in macrophages and synovial fibroblasts, indicating a stronger anti-inflammatory effect. These results suggest UC-MSC exosomes as a promising therapeutic option for OA, with the potential for modulating inflammation and promoting joint tissue regeneration.

Establishment of a Posttraumatic Osteoarthritis Model in Mice Induced by Noninvasive Anterior Cruciate Ligament Tear

BACKGROUND

Animal models that use open surgical transection of the anterior cruciate ligament (ACL) do not accurately simulate the clinical condition regarding the pivot-shift mechanism and the associated inflammatory response that occurs before reconstruction.

PURPOSE/HYPOTHESIS

The purpose was to characterize a reproducible manual, nonsurgical method to mimic an isolated ACL tear in a clinically relevant model and to evaluate the development of progressive posttraumatic osteoarthritis due to ACL injury. It was hypothesized that the ACL could be reproducibly torn with minimal damage to other ligaments and that there would be progressive development of degenerative joint disease after ACL injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 37 mice (strain C57BL/6) were used to compare the manual procedure with sham surgery (sham group; n = 10) and with the established surgical ACL transection (ACLT) procedure (surgical group; n = 27). In the sham group, a closed manual procedure was performed on the right knee and sham surgery on the left knee. In the surgical group, the closed manual procedure was performed on the right knee and surgical ACLT on the left knee. Dissection using India ink, histological assessment with safranin O and hematoxylin-eosin staining, radiological evaluation through radiographs and microfocus computed tomography scans, and gait analyses were performed to assess cartilage/ligament status. Osteoarthritis Research Society International (OARSI) and synovitis scores, anterior tibial translation, range of motion, bone microstructure, osteophyte volume, and pain were assessed at 2, 4, and 8 weeks postoperatively.

RESULTS

The manual procedure successfully resulted in an ACL rupture and associated meniscal injury. The posterior cruciate, lateral collateral, and medial collateral ligaments were intact in all dissected knees. Two weeks after ACL tear, the surgical group showed a significantly higher synovitis score, whereas 8 weeks after ACL tear, the manual group showed a significantly higher volume of osteophytes. No significant differences were found between the groups in terms of OARSI score, anterior tibial translation, range of motion, bone microstructure computed tomography values, and stride distance/irregularity.

CONCLUSION

This procedure can be used to create an ACL tear model without causing grossly evident injuries to other ligaments and avoiding the risk of cartilage damage from surgical instruments.

CLINICAL RELEVANCE

This procedure offers a more clinically relevant ACL tear model and facilitates simple, inexpensive, and reproducible development of posttraumatic osteoarthritis.

Mesenchymal stem cells in synovial fluid increase in number in response to synovitis and display more tissue-reparative phenotypes in osteoarthritis

BACKGROUND

Synovial fluid mesenchymal stem cells (SF-MSCs) originate in the synovium and contribute to the endogenous repair of damaged intra-articular tissues. Here, we clarified the relationship between their numbers and joint structural changes during osteoarthritis (OA) progression and investigated whether SF-MSCs had phenotypes favorable for tissue repair, even in an OA environment.

METHODS

Partial medial meniscectomy (pMx) and sham surgery were performed on both knees of rats. SF and knee joints were collected from intact rats and from rats at 2, 4, and 6 weeks after surgery. SF was cultured for 1 week to calculate the numbers of colony-forming cells and colony areas. Joint structural changes were evaluated histologically to investigate their correlation with the numbers and areas of colonies. RNA sequencing was performed for SF-MSCs from intact knees and knees 4 weeks after the pMx and sham surgery.

RESULTS

Colony-forming cell numbers and colony areas were greater in the pMx group than in the intact and sham groups and peaked at 2 and 4 weeks, respectively. Synovitis scores showed the strongest correlation with colony numbers (R = 0.583) and areas (R = 0.456). RNA sequencing revealed higher expression of genes related to extracellular matrix binding, TGF-β signaling, and superoxide dismutase activity in SF-MSCs in the pMx group than in the sham group.

CONCLUSION

The number of SF-MSCs was most closely correlated with the severity of synovitis in this rat OA model. Tissue-reparative gene expression patterns were observed in SF-MSCs from OA knees, but not from knees without intra-articular tissue damage.

Study of the Early Effects of Chitosan Nanoparticles with Glutathione in Rats with Osteoarthrosis

Due to cartilage's limited capacity for regeneration, numerous studies have been conducted to find new drugs that modify osteoarthrosis's progression. Some evidence showed the capability of chitosan nanoparticles with glutathione (Np-GSH) to regulate the oxide-redox status in vitro in human chondrocytes. This work aimed to evaluate the capacity of Np-GSH in vivo, using Wistar rats with induced surgical osteoarthritis. Radiographic, biochemical (GSH and TBARS quantification), histopathological, and immunohistochemical (Col-2 and MMP-13) analyses were performed to evaluate the progress of the osteoarthritic lesions after the administration of a single dose of Np-GSH. According to the results obtained, the GSH contained in the NPs could be vectored to chondrocytes and used by the cell to modulate the oxidative state reduction, decreasing the production of ROS and free radicals induced by agents oxidizing xenobiotics, increasing GSH levels, as well as the activity of GPx, and decreasing lipid peroxidation. These results are significant since the synthesis of GSH develops exclusively in the cell cytoplasm, and its quantity under an oxidation-reduction imbalance may be defective. Therefore, the results allow us to consider these nanostructures as a helpful study tool to reduce the damage associated with oxidative stress in various diseases such as osteoarthritis.

Thawed cryopreserved synovial mesenchymal stem cells show comparable effects to cultured cells in the inhibition of osteoarthritis progression in rats

Intra-articular injections of mesenchymal stem cells (MSCs) can inhibit the progression of osteoarthritis (OA). Previous reports have used cultured MSCs, but the ability to use thawed cryopreserved MSC stocks would be highly advantageous. Our purpose was to elucidate whether thawed cryopreserved MSCs show comparable inhibitory effects on OA progression in rats to those obtained with cultured MSCs. Cultured rat synovial MSCs or thawed MSCs were compared for in vitro viability and properties. The inhibitory effect of thawed MSCs on OA progression was evaluated by injecting cryopreservation fluid and thawed MSCs in meniscectomized rats. Cartilage degeneration was assessed using gross finding and histological scores. Cultured MSCs were then injected into one knee and thawed MSCs into the contralateral knee of the same individual to compare their effects. Cultured MSCs and MSCs thawed after cryopreservation had comparable in vitro colony formation and chondrogenic potentials. In the rat OA model, the gross finding and histological scores were significantly lower in the thawed MSC group than in the cryopreservation fluid group at 8 weeks. Finally, cartilage degeneration did not differ significantly after injection of cultured and thawed MSCs. In conclusion, thawed MSCs showed comparable inhibitory effects on OA progression to cultured MSCs.

Viscosupplementation may preserve tibial cartilage and collagen in osteoarthritis: findings from a preclinical model of osteoarthritis

PURPOSE

Intraarticular (IA) hyaluronic acid (HA) injection is used to reduce pain and improve mobility in knee osteoarthritis (OA). Little is known about histopathological changes underlying HA efficacy. This study investigated dose-related effects of 1% sodium hyaluronate (BioHA) on knee joint histopathology and pain responses in a medial meniscal tear (MMT) rat model of OA.

METHODS

Following MMT surgery, rats were randomized into treatment groups: single IA injection of vehicle, BioHA, or an avian-derived hyaluronic acid (hylan G-F 20) on Day 7; or 3 weekly injections of vehicle or BioHA on Days 7, 14, and 21. On Day 35, joints were evaluated by microscopic histopathology for cartilage degeneration, collagen degeneration, synovitis, and cytokine expression (tumor necrosis factor α, transforming growth factor β).

RESULTS

Joint pathology for control animals was consistent with that expected for the MMT model. Rats treated with 3 injections of IA-BioHA had significantly reduced collagen degeneration (21%) relative to control animals. No significant change in collagen degeneration was observed for rats given a single injection of hylan G-F 20 or IA-BioHA compared to control animals. HA treatment did not affect cytokine expression.

CONCLUSIONS

IA-BioHA viscosupplementation in a rat MMT model of OA showed preservation of joint cartilage and collagen. This effect was most pronounced on tibial surfaces having less severe injury, suggesting that treatment should be initiated early in the disease process. A comparison of responses to IA-BioHA or hylan G-F 20 in the MMT rat OA model suggest IA-BioHA may be more effective in preserving joint connective tissue.

Characterization of Osteoarthritis in a Medial Meniscectomy-Induced Animal Model Using Contrast-Enhanced X-ray Microtomography

The aim of this study was to clarify degradation characteristics in each tissue of the knee complex of a medial meniscectomy (MMx)-induced knee osteoarthritis (KOA) animal model using classical methods and an alternative comprehensive evaluation method called contrast-enhanced X-ray micro-computed tomography (CEX-μCT), which was developed in the study. Surgical MMx was performed in the right knee joints of five male Wistar rats to induce KOA. At four weeks post-surgery, the synovitis was evaluated using quantitative polymerase chain reaction (qPCR). Degradations of the articular cartilage of the tibial plateau were evaluated using classical methods and CEX-μCT. Evaluation of the synovitis demonstrated significantly increased expression levels of inflammation-associated marker genes in MMx-treated knees compared with those in sham-treated knees. Evaluation of the articular cartilage using classical methods showed that MMx fully induced degradation of the cartilage. Evaluation using CEX-μCT showed that local areas of the medial cartilage of the tibial plateau were significantly reduced in MMx-treated knees compared with those in sham-treated knees. On the other hand, total cartilage volumes were significantly increased in MMx-treated knees. On the basis of the findings of this study, the method could be relevant to study new treatments in KOA research.

Decision Algorithms for the Retreatment with Viscosupplementation in Patients Suffering from Knee Osteoarthritis: Recommendations from the EUROpean VIScosupplementation COnsensus Group (EUROVISCO)

Background Viscosupplementation (VS) is a symptomatic treatment of knee osteoarthritis. Although systematic reviews of its repeat use showed favorable benefit/risk ratio, no study has focused on the indication of retreatment. Methods A task force was created to look at issues regarding retreatment with VS in knee osteoarthritis. An attempt was made to reach consensus on several issues: (1) to define treatment "success" and "failure," (2) to determine when to retreat patients successfully treated by a previous VS, (3) to determine how to retreat patients in whom VS failed, (4) to define what to do in case of adverse reaction following previous VS, and (5) to examine the interests of soluble biomarkers to manage retreatment. After debate and review of literature the working group voted on 88 issues. Two "decision trees" were built based on the results of the votes. Results In case of failure, the authors draw attention to the need of a rigorous clinical and radiological analysis, and consider evidence-based medicine. When VS was previously successful, retreatment can be considered after recurrence or increase in pain. However, in subjects with high risk of disease progression, in young patients, and in professional sportsmen, retreatment could be considered systematically, because of the probability of hyaluronic acid to slow osteoarthritis progression. Evidence on soluble biomarkers was not considered as enough strong to support their use as decision tools for patient retreatment. Conclusion The decision algorithms are intended to facilitate consideration of the therapeutic options, in patients with knee osteoarthritis previously treated with VS.

Centralization of extruded medial meniscus delays cartilage degeneration in rats

BACKGROUND

Meniscus extrusion often observed in knee osteoarthritis has a strong correlation with the progression of cartilage degeneration and symptom in the patients. We recently reported a novel procedure "arthroscopic centralization" in which the capsule was sutured to the edge of the tibial plateau to reduce meniscus extrusion in the human knee. However, there is no animal model to study the efficacy of this procedure. The purposes of this study were [1] to establish a model of centralization for the extruded medial meniscus in a rat model; and [2] to investigate the chondroprotective effect of this procedure.

METHODS

Medial meniscus extrusion was induced by the release of the anterior synovial capsule and the transection of the meniscotibial ligament. Centralization was performed by the pulled-out suture technique. Alternatively, control rats had only the medial meniscus extrusion surgery. Medial meniscus extrusion was evaluated by micro-CT and macroscopic findings. Cartilage degeneration of the medial tibial plateau was evaluated macroscopically and histologically.

RESULTS

By micro-CT analysis, the medial meniscus extrusion was significantly improved in the centralization group in comparison to the extrusion group throughout the study. Both macroscopically and histologically, the cartilage lesion of the medial tibial plateau was prevented in the centralization group but was apparent in the control group.

CONCLUSIONS

We developed medial meniscus extrusion in a rat model, and centralization of the extruded medial meniscus by the pull-out suture technique improved the medial meniscus extrusion and delayed cartilage degeneration, though the effect was limited. Centralization is a promising treatment to prevent the progression of osteoarthritis.