Biological Regeneration of Articular Cartilage in an Early Stage of Compartmentalized Osteoarthritis: 12-Month Results

Evaluation of cartilage degeneration using multiparametric quantitative ultrashort echo time-based MRI: an ex vivo study

BACKGROUND

The quantitative MR techniques developed rapidly, vary MR-biomarkers have shown the ability to assess the quality of articular cartilage. This study aimed to investigate the diagnostic efficacy of multi-parametric quantitative ultrashort echo time (UTE)-based MRI for evaluating human cartilage degeneration.

METHODS

Twenty fresh anterolateral femoral condyle samples were obtained from 20 patients (age, 58.8±6.6 years; 6 females) who underwent total knee arthroplasty due to primary osteoarthritis (OA). The samples were imaged using UTE-based magnetization transfer (UTE-MT), UTE-based adiabatic T1ρ (UTE-AdiabT1ρ), UTE-based T2* (UTE-T2*), and CubeQuant-T2 sequences. Cartilage degeneration was classified based on the OA Research Society International grade and polarized light microscopy (PLM) collagen organization score. Spearman's correlation analysis was used to determine the relationships between quantitative MRI biomarkers [UTE-MT ratio (UTE-MTR), UTE-AdiabT1ρ, UTE-T2*, and CubeQuant-T2], OA Research Society International grade, and PLM collagen organization score. The diagnostic efficacy of each MRI biomarker for the detection of mild cartilage degeneration was assessed using the area under the receiver operating characteristic (ROC) curve (AUC).

RESULTS

Of the quantitative MRI biomarkers, UTE-MTR had the strongest correlation with both OA Research Society International grade (r=-0.709, P<0.001) and PLM collagen organization score (r=0.579, P<0.001). The UTE-MTR and UTE-AdiabT1ρ values showed significant differences between the normal group and the mild degeneration group (P=0.047 and 0.015, respectively), while UTE-T2* and CubeQuant-T2 did not. The UTE-MTR values were 15.90%±1.06% and 14.59%±1.35% for normal and mildly degenerated cartilage, respectively. The UTE-AdiabT1ρ values were 40.19±2.87 and 42.6±2.26 ms for normal and mildly degenerated cartilage, respectively. ROC analysis showed that UTE-MTR (AUC =0.805, P=0.001, sensitivity =73.7%, specificity =89.5%) had the highest diagnostic efficacy for mild cartilage degeneration, while UTE-AdiabT1ρ (AUC =0.727, P=0.017) and CubeQuant-T2 (AUC =0.712, P=0.026) showed lower diagnostic efficacy.

CONCLUSIONS

Quantitative UTE-MT and UTE-AdiabT1ρ biomarkers may potentially be used in the evaluation of early cartilage degeneration.

Circumferential Rim Augmentation Suture Around the Perimeniscal Capsule Decreases Meniscal Extrusion and Progression of Osteoarthritis in Rabbit Meniscus Root Tear Model

BACKGROUND

We recently analyzed the joint capsule adjacent to the medial meniscus and found that the perimeniscal joint capsule has collagen fiber orientation similar to that of circumferential meniscal fibers, potentially playing a role in preventing extrusion.

PURPOSE

To analyze the meniscal extrusion prevention potential of the circumferential rim augmentation suture around the perimeniscal capsule in a rabbit root tear model and analyze the biomechanical function in a porcine cadaveric knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Rabbit medial meniscus root tear models were divided into 3 experimental groups: root tear, root tear and suture repair, and root tear and circumferential rim augmentation suture. As for the circumferential rim augmentation suture procedure, a suture was placed to circumscribe the outer rim of the medial meniscus and passed through bone tunnels located at the tibial insertion of each root. After 4 and 8 weeks, meniscal extrusion was analyzed by micro-computed tomography, gross morphology, and histologic analysis of the medial femoral cartilage. For biomechanical analysis, porcine knees were divided into groups similar to rabbit experiments. Tibiofemoral contact parameters were assessed using a pressure mapping sensor system after applying a load of 200 N on the knee joint.

RESULTS

The root tear and circumferential rim augmentation suture group showed less meniscal extrusion, less gap within the tear site, and less cartilage degeneration compared with other groups after 4 and 8 weeks of surgery in the rabbit root tear model. Biomechanical analysis showed the root tear and circumferential rim augmentation suture group had larger contact area and lower peak contact pressure compared with root tear and root tear and suture repair groups.

CONCLUSION

The circumferential rim augmentation suture reduced the degree of meniscal extrusion while restoring meniscal function, potentially preventing progression of arthritis in a rabbit root tear model and porcine knee biomechanical analysis.

CLINICAL RELEVANCE

The circumferential rim augmentation suture may be a novel augmentation option during root tear treatment.

rAAV-Mediated sox9 Overexpression Improves the Repair of Osteochondral Defects in a Clinically Relevant Large Animal Model Over Time In Vivo and Reduces Perifocal Osteoarthritic Changes

BACKGROUND

Gene transfer of the transcription factor SOX9 with clinically adapted recombinant adeno-associated virus (rAAV) vectors offers a powerful tool to durably enhance the repair process at sites of osteochondral injuries and counteract the development of perifocal osteoarthritis (OA) in the adjacent articular cartilage.

PURPOSE

To examine the ability of an rAAV sox9 construct to improve the repair of focal osteochondral defects and oppose perifocal OA development over time in a large translational model relative to control gene transfer.

STUDY DESIGN

Controlled laboratory study.

METHODS

Standardized osteochondral defects created in the knee joints of adult sheep were treated with rAAV-FLAG-hsox9 relative to control (reporter) rAAV-lacZ gene transfer. Osteochondral repair and degenerative changes in the adjacent cartilage were monitored using macroscopic, histological, immunohistological, and biochemical evaluations after 6 months. The microarchitecture of the subchondral bone was assessed by micro-computed tomography.

RESULTS

Effective, prolonged sox9 overexpression via rAAV was significantly achieved in the defects after 6 months versus rAAV-lacZ treatment. The application of rAAV-FLAG-hsox9 improved the individual parameters of defect filling, matrix staining, cellular morphology, defect architecture, surface architecture, subchondral bone, and tidemark as well as the overall score of cartilage repair in the defects compared with rAAV-lacZ. The overexpression of sox9 led to higher levels of proteoglycan production, stronger type II collagen deposition, and reduced type I collagen immunoreactivity in the sox9- versus lacZ-treated defects, together with decreased cell densities and DNA content. rAAV-FLAG-hsox9 enhanced semiquantitative histological subchondral bone repair, while the microstructure of the incompletely restored subchondral bone in the sox9 defects was not different from that in the lacZ defects. The articular cartilage adjacent to the sox9-treated defects showed reduced histological signs of perifocal OA changes versus rAAV-lacZ.

CONCLUSION

rAAV-mediated sox9 gene transfer enhanced osteochondral repair in sheep after 6 months and reduced perifocal OA changes. These results underline the potential of rAAV-FLAG-hsox9 as a therapeutic tool to treat cartilage defects and afford protection against OA.

CLINICAL RELEVANCE

The delivery of therapeutic rAAV sox9 to sites of focal injuries may offer a novel, convenient tool to enhance the repair of osteochondral defects involving both the articular cartilage and the underlying subchondral bone and provide a protective role by reducing the extent of perifocal OA.

Bone marrow aspirate concentrate and scaffold for osteochondral lesions of the talus in ankle osteoarthritis: satisfactory clinical outcome at 10 years

PURPOSE

To evaluate at long-term follow-up patients undergoing a one-step procedure of debridement and BMAC seeded in situ onto a scaffold for the treatment of osteochondral lesions of the talus (OLT) in ankles affected by osteoarthritis (OA), documenting the duration of the clinical benefit and its efficacy in postponing end-stage procedures.

METHODS

This series included 56 consecutive patients. Patients were evaluated preoperatively and up to a mean of 10 years of follow-up with the AOFAS score and the AOS scale, including pain and disability subscales. Furthermore, patients were asked to rate the satisfaction and failures were documented as well.

RESULTS

The AOFAS score improved from 52.3 ± 14.3 to 73.5 ± 23.1 at 10 years (p  < 0.0005); the AOS pain and disability subscales decreased from 70.9 ± 14.1 to 37.2 ± 32.7 and from 69.0 ± 14.8 to 34.2 ± 29.3, respectively (both p < 0.0005). The overall rate of satisfaction was 61.8 ± 41.2 and 68.6% of patients would undergo again the surgical procedure. A total of 17 failures was documented, for a failure rate of 33.3%. Older patients and those with more complex cases requiring previous or combined surgeries had lower outcomes, as well as those affected by grade 3 OA, who experienced a high failure rate of 71.4%.

CONCLUSIONS

This one-step technique for the treatment of OLT in OA ankles showed to be safe and to provide a satisfactory outcome, even if patients with end stage OA presented a high revision rate at 10 years. Moreover, this procedure was effective over time, with overall good results maintained up to a long-term follow-up. However, older age, more complex cases requiring previous or combined surgeries, and advanced OA led to an overall worst outcome and a significantly higher failure rate.

CircHYBID regulates hyaluronan metabolism in chondrocytes via hsa-miR-29b-3p/TGF-β1 axis

Background

Hyaluronan (HA) metabolism by chondrocytes is important for cartilage development and homeostasis. However, information about the function of circular RNAs (circRNAs) in HA metabolism is limited. We therefore profiled the role of the novel HA-related circRNA circHYBID in the progression of osteoarthritis (OA).

Methods

CircHYBID function in HA metabolism in chondrocytes was investigated using gain-of-function experiments, and circHYBID mechanism was confirmed via bioinformatics analysis and luciferase assays. The expression of circHYBID–hsa-miR-29b-3p–transforming growth factor (TGF)-β1 axis was examined by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. CircHYBID, TGF-β1, and HA levels in cartilage samples were evaluated using qRT-PCR and pathological examination. Enzyme-linked immunosorbent assay was used to assess HA accumulation in chondrocyte supernatant.

Results

CircHYBID expression was significantly downregulated in damaged cartilage samples compared with that in the corresponding intact cartilage samples. CircHYBID expression was positively correlated with alcian blue score. Interleukin-1β stimulation in chondrocytes downregulated circHYBID expression and decreased HA accumulation. Gain-of-function experiments revealed that circHYBID overexpression in chondrocytes increased HA accumulation by regulating HA synthase 2 and HYBID expression. Further mechanism analysis showed that circHYBID upregulated TGF-β1 expression by sponging hsa-miR-29b-3p.

Conclusions

Our results describe a novel HA-related circRNA that could promote HA synthesis and accumulation. The circHYBID–hsa-miR-29b-3p–TGF-β1 axis may play a powerful regulatory role in HA metabolism and OA progression. Thus, these findings will provide new perspectives for studies on OA pathogenesis, and circHYBID may serve as a potential target for OA therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00319-x.

Noncoding RNAs in subchondral bone osteoclast function and their therapeutic potential for osteoarthritis

Osteoclasts are the only cells that perform bone resorption. Noncoding RNAs (ncRNAs) are crucial epigenetic regulators of osteoclast biological behaviors ranging from osteoclast differentiation to bone resorption. The main ncRNAs, including miRNAs, circRNAs, and lncRNAs, compose an intricate network that influences gene transcription processes related to osteoclast biological activity. Accumulating evidence suggests that abnormal osteoclast activity leads to the disturbance of subchondral bone remodeling, thus initiating osteoarthritis (OA), a prevalent joint disease characterized mainly by cartilage degradation and subchondral bone remodeling imbalance. In this review, we delineate three types of ncRNAs and discuss their related complex molecular signaling pathways associated with osteoclast function during bone resorption. We specifically focused on the involvement of noncoding RNAs in subchondral bone remodeling, which participate in the degradation of the osteochondral unit during OA progression. We also discussed exosomes as ncRNA carriers during the bone remodeling process. A better understanding of the roles of ncRNAs in osteoclast biological behaviors will contribute to the treatment of bone resorption-related skeletal diseases such as OA.