No Effect of Long-Term Risedronate Use on Cartilage and Subchondral Bone in an Experimental Rabbit Model of Osteoarthritis

Medial tibial plateau sustaining higher physiological stress than the lateral plateau: based on 3D printing and finite element method

Background

Medial compartment knee osteoarthritis (KOA) accounts for most KOA cases, and increased trabecular bone volume fraction (BV/TV) is one of the pathological changes in the tibial plateau of KOA. How BV/TV changes before and after the menopause and its effects on medial compartment KOA are yet to be clarified.

Methods

Twenty femurs from twenty 12-week-old rats were included. The operated group underwent ovariectomy (to represent the osteoporosis condition), called the O group, and the non-operated group was the normal control, called the N group. Micro-CT scans of the femoral condyles were acquired 12 weeks after the surgery, and the volume of interest (VOI) of medial-, inter-, and lateral-condyle trabeculae were three-dimensional (3D) printed for uniaxial compression mechanical test and simulated by the finite element (FE) method.

Results

The results demonstrated that the O group indicated poorer trabecular architecture than the N group in three parts of the femoral condyle, especially in the intercondyle. Within the group, the BV/TV, trabecular thickness (Tb.Th), and trabecular number (Tb.N) ratios between the medial and lateral condyles were greater than 1 in both N and O groups. The medial condyle trabeculae's mechanical properties were higher than those of the lateral condyle, and this superiority appears to be broadened under osteoporotic conditions. FE modelling well reproduced these mechanical differentiations.

Conclusions

According to Wolff's law, the higher BV/TV and mechanical properties of the medial femoral condyle may be due to inherent imbalanced loading on the knee component. Alterations in BV/TV and their corresponding mechanical properties may accompany KOA.

A Composite Deferoxamine/Black Phosphorus Nanosheet/Gelatin Hydrogel Scaffold for Ischemic Tibial Bone Repair

Introduction

Bone delay union is mostly caused by lack of blood supply. Although autografts, allografts and artificial bone have been widely used to treat bone delay union, the bone regeneration fails in the ischemic site accompanied by the bone donor site complications and disease transmission. Recently, there is a growing recognition of the importance of hydrogel scaffolds which are regarded as an eligible engineer tissue for bone repair. However, hydrogel is still limited in improving neovascularization.

Methods

In this work, black phosphorus nanosheet and deferoxamine (BPN-DFO) were loaded in the gelatin hydrogel to overcome the high risk of bone delay union and systemically investigated the regeneration capability of BPN-DFO hydrogel in vitro and vivo.

Results

The resulting BPN-DFO hydrogel scaffold showed superior swollen, degradation and release rate, as well as satisfied biocompatibility. BPN-DFO hydrogel shown the significant up-expression of mRNA related to bone regeneration and cell proliferation. In vivo, the proposed BPN-DFO hydrogel significantly improved osteogenesis and neovascularization in the ischemic tibial bone site of SD rats with acute femoral artery occlusion. Both macroscopic and histological evaluation of new regenerated bone showed newly formed blood vessel and collagen using BPN-DFO hydrogel. The immunohistochemistry and RT-PCR revealed that the bone regeneration could be improved via BMP/Runx2 pathway.

Conclusion

The BPN-DFO hydrogel possesses potential tissue engineer material for ischemic bone defect treatment. However, furthermore studies are needed to testify the safety and efficacy of BPN-DFO hydrogel.

Does Bisphosphonate Increase the Sclerosis of Tibial Subchondral Bone in the Progression of Knee Osteoarthritis-A Propensity Score Matching Cohort Study Based on Osteoarthritis Initiative

Bisphosphonate has great potential in KOA therapy, but whether the anti-resorption mechanism of bisphosphonate aggravates sclerosis of subchondral bone remains unclear. We found that bisphosphonate use did not increase sclerosis of subchondral bone in established KOA, perhaps resolving some concerns about bisphosphonate in patients with KOA. Introduction: Most studies have focused on the protective effect of bisphosphonate on early knee osteoarthritis (KOA) through its anti-resorption mechanism in osteoclasts. However, late KOA has a decreased rate of resorption, which is the opposite of early KOA. The risk of subchondral bone sclerosis in late KOA after using bisphosphonate has not been investigated using morphometry. Methods: Forty-five patients who had ever used bisphosphonate (or 33 patients with current use) were matched with controls through propensity matching methods, including age, body mass index (BMI), sex, health status (12-Item Short Form Survey physical health score), physical activity level (Physical Activity Scale for the Elderly score), vitamin D use, and calcium use. At the baseline and 12-month (or 18-month) follow-up, bone mineral density (BMD) of the tibia and hip was measured by dual-energy X-ray absorptiometry (DXA), and medial tibial subchondral bone morphometry: bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) were calculated based on 3-T trabecular MRI. Data were obtained from the Bone Ancillary Study in the Osteoarthritis Initiative (OAI) project. Results: The yearly percentage change in hip BMD of the current bisphosphonate-use group was significantly greater than that of the non-bisphosphonate-use group (0.7% vs. -1%, P = 0.02). The other outcomes (BV/TV, Tb.N, Tb.Sp, Tb.Th, tibia medial BMD, and tibia lateral BMD) between the two groups presented no significant difference. The non-bisphosphonate-use group experienced a significant increase in Tb.Th [2%, 95% CI = (1%, 4%), P = 0.01], while the bisphosphonate-use group presented no significant change [1%, 95% CI = (-2%, 4%), P = 0.54]. Conclusions: Bisphosphonate use did not increase sclerosis of subchondral bone in established KOA. Bisphosphonate might have a stage-dependent effect on subchondral bone in KOA initiation and progression.

Effects of adenovirus-mediated knockdown of IRAK4 on synovitis in the osteoarthritis rabbit model

BACKGROUND

The use of interleukin-1 receptor-associated kinase 4 (IRAK4) inhibitor as a treatment for the inflammatory joint disease is a promising method. However, its underlying mechanism in osteoarthritis (OA) remains unclear. The purpose of this study is to look into the effects of adenovirus-mediated knockdown of IRAK4 on synovitis in the OA rabbit model.

METHODS

Ad-shIRAK4 was injected two weeks after anterior cruciate ligament resection. Six weeks later, the rabbits were killed. The expression of IRAK4, TNFR-associated factor 6(TRAF6), TGF-activated kinase 1(TAK1), p-IKB kinase (p-IKK), p-nuclear factor kappa-B (p-NFκB), p38, and p-p38 in the synovial membrane was detected by western blot, qRT-PCR, and immunohistochemistry analysis. Immunohistochemistry was to detect the expression of IRAK4 proteins in articular cartilage. H&E staining was to assess the pathological changes of synovium and cartilage. The levels of interleukin (IL)-1β, tumor necrosis factor-α(TNF-α), and MMP-13 in the synovial fluid were measured by ELISA. X-ray and micro-computerized tomography (μCT) scans were used to assess knee joint conditions and microstructure of subchondral bone.

RESULTS

IRAK4 expression levels in synovial tissues of the OA model group exhibited a significant upward trend. Ad-shIRAK4 significantly reduced IRAK4 mRNA expression in synovium tissues. Notably, Ad-shIRAK4 suppressed the Toll-like receptor/interleukin-1 receptor (TLR/IL-1R) signaling. In addition, in the Ad-shIRAK4 treatment group, we can see less inflammatory cell infiltration and reduced hyperplasia and angiogenesis. The levels of IL-1β, TNF-α, and MMP-13 in the synovial fluid in the OA model group were significantly higher than that in the control group, which were reduced by Ad-shIRAK4 treatment. Finally, Results of HE stains, immunohistochemistry, and μCT showed that Ad-shIRAK4 treatment has a protective effect on cartilage damage.

CONCLUSIONS

IRAK4 is significantly upregulated in the synovium from the osteoarthritis rabbit model. In addition, Ad-shIRAK4 reduced the expression of IRAK4 and suppressed TLR/IL-1R signaling in the synovium from the osteoarthritis rabbit model. Ad-shIRAK4 could alleviate synovitis and cartilage degradation in the osteoarthritis rabbit model, and thus alleviate the symptoms of OA and prevent the progression of OA.

Histomorphometric Quantitative Evaluation of Long-Term Risedronate Use in a Knee Osteoarthritis Rabbit Model

Osteoarthritis (OA) treatment is a major orthopedic challenge given that there is no ideal drug capable to reverse or stop the progression of the OA. In that regard, bisphosphonates have been proposed as potential disease-modifying drugs due to their possible chondroprotective effect related to obtaining a greater subchondral bone quality. However, their effectiveness in OA is still controversial and additionally, there is little evidence focused on their long-term effect in preclinical studies. The aim of this study was to evaluate the risedronate quantitative effect on articular and subchondral periarticular bone by histomorphometry, in an experimental rabbit model in an advanced stage of OA. Twenty-four adult New Zealand rabbits were included in the study. OA was surgically induced in one randomly chosen knee, using the contralateral as healthy control. Animals were divided into three groups (n = 8): placebo control group, sham surgery group and risedronate-treated group. After 24 weeks of treatment, cartilage and subchondral femorotibial pathology was evaluated by micro-computed tomography (micro-CT) and undecalcified histology. The research results demonstrated that the experimental animal model induced osteoarthritic changes in the operated joints, showing an increased cartilage thickness and fibrillation associated with underlying subchondral bone thinning and decreased trabecular bone quality. These changes were especially highlighted in the medial tibial compartments as a possible response to surgical instability. Regarding the trabecular analysis, significant correlations were found between 2D histomorphometry and 3D imaging micro-CT for the trabecular bone volume, trabecular separation, and the trabecular number. However, these associations were not strongly correlated, obtaining more precise measurements in the micro-CT analysis. Concerning the long-term risedronate treatment, it did not seem to have the capacity to reduce the osteoarthritic hypertrophic cartilage response and failed to diminish the superficial cartilage damage or prevent the trabecular bone loss. This study provides novel information about the quantitative effect of long-term risedronate use on synovial joint tissues.