Osteoarthritic Articular Cartilage Research Articles

Stem cell therapy for knee osteoarthritis: a narrative review of a rapidly evolving treatment with implications for physical therapy management

Background: Stem cell therapy has emerged as a new, exciting treatment for repair of articular cartilage in osteoarthritis (OA), which currently has no cure. Regenerative cell therapies can potentially offer alternatives to total joint replacement for patients with OA. A variety of cell-based therapies have been developed involving the use of autologous and allogeneic mesenchymal stem cells (MSCs). To date, these stem cell therapies have been shown to be safe and efficacious, but information on the long-term clinical outcomes for joint function is lacking. Also lacking is information regarding post-treatment rehabilitation strategies and their effects.Objectives: The purpose of this narrative review was to evaluate the current literature in relation to stem cell therapy for knee OA and to highlight the importance of physical therapists establishing and researching suitable care management and rehabilitation procedures for patients receiving stem cell therapy.Major findings: The results of this literature review show that MSCs have been safe and effective at reducing pain and improving joint functionality and cartilage quality. The review also found that both autologous and allogeneic stem cells were able to produce similar clinical improvements in pain scores and cartilage repair and restoration. There is a lack of research evaluating the influence of rehabilitation on cartilage repair.Conclusions: Current research shows that significant improvements in joint pain and function continue for approximately 2-year post-stem cell procedure. There is currently a lack of research into rehabilitation protocols which could potentially improve joint function further.

Semaphorin 4A acts in a feed-forward loop with NF-κB pathway to exacerbate catabolic effect of IL-1β on chondrocytes

Inflammation is fundamental in osteoarthritis (OA) pathogenesis. Semaphorin 4A (Sema4A) has been implicated in immune-associated diseases, however, its role in OA remains unclear. In this study, we show that Sema4A is upregulated in knee OA articular cartilage as well as in chondrocytes exposed to IL-1β treatment in vitro. Moreover, IL-1β-induced Sema4A upregulation is abrogated in the presence of BAY 11-7082, a specific inhibitor of NF-κB pathway, suggesting that the activation of NF-κB is required for Sema4A upregulation under this pathological condition. Intriguingly, Sema4A in turn activates NF-κB through facilitating Rac1/AKT-dependent IκBα phosphorylation and subsequent degradation. Functionally, Sema4A aggravates the catabolic effect of IL-1β on chondrocytes, which can be largely attributed to exacerbated NF-κB activation, since NF-κB inhibition remarkably abolishes this effect. In conclusion, our study suggests that Sema4A is a novel regulator of NF-κB-dependent catabolic events in chondrocytes, which may underlie OA pathogenesis.

Discoidin domain receptor 2: An emerging pharmacological drug target for prospective therapy against osteoarthritis.

Discoidin domain receptor2 (DDR2), a cell membrane tyrosine kinase on chondrocytes surface plays main role in cell-ECM interaction during the progressive degeneration of articular cartilage in osteoarthritis. The degraded component of ECM, type II collagen upon DDR2 binding provokes synthesis of matrix metalloproteinases (MMPs), responsible for severe destruction of joint tissues. DDR2 knockout has been investigated to decline the expression of MMP-1 and 13. Previously, various molecules were effective in preclinical level against different targets in OA, but found to be collapsed in clinical trial due to insufficient target specificity and clinical toxicity. Review emphasizes the role of DDR2 in the degeneration of cartilage in osteoarthritis (OA) and its blocking by DDR2 antagonist attenuates the disease severity. DDR2 in chondrocytes contributes paramount role in degradation of cartilage at early stage of osteoarthritis via collagen 2 binding through the felicitation of TGF-β signaling molecule and other triggering factors. DDR2 involvement in regulation of matrix metalloproteinase (MMP), cross talking interaction in maintenance of ECM-chondrocytes, bone developments, interference RNA and designing the DDR2 antagonists have been critically investigated. The exploration may conclude that the DDR2 could be the novel pharmacological target to prevent the progression of osteoarthritis at early stage because of over expression of DDR2 and MMP which further promotes severe cartilage degeneration. Owing to pharmacological specificity of DDR2 in OA as drug target, it is to be hypothesized that development of safe molecules as DDR2 antagonist could be the good option in the treatment of OA with promising landmark.

Increased WISP1 expression in human osteoarthritic articular cartilage is epigenetically regulated and decreases cartilage matrix production.

Previously, we have shown the involvement of Wnt-activated protein Wnt-1-induced signaling protein 1 (WISP1) in the development of OA in mice. Here, we aimed to characterize the relation between WISP1 expression and human OA and its regulatory epigenetic determinants. Preserved and lesioned articular cartilage from end-stage OA patients and non-OA-diagnosed individuals was collected. WISP1 expression was determined using immunohistochemistry and damage was classified using Mankin scoring. RNA expression and DNA methylation were assessed in silico from genome-wide datasets (microarray analysis and RNA sequencing, and 450 k-methylationarrays, respectively). Effects of WISP1 were tested in pellet cultures of primary human chondrocytes. WISP1 expression in cartilage of OA patients was increased compared with non-OA-diagnosed controls and, within OA patients, WISP1 was even higher in lesioned compared with preserved regions, with expression strongly correlating with Mankin score. In early symptomatic OA patients with disease progression, higher synovial WISP1 expression was observed as compared with non-progressors. Notably, increased WISP1 expression was inversely correlated with methylation levels of a positional CpG-dinucleotide (cg10191240), with lesioned areas showing strong hypomethylation for this CpG as compared with preserved cartilage. Additionally, we observed that methylation levels were allele-dependent for an intronic single-nucleotide polymorphism nearby cg10191240. Finally, addition of recombinant WISP1 to pellets of primary chondrocytes strongly inhibited deposition of extracellular matrix as reflected by decreased pellet circumference, proteoglycan content and decreased expression of matrix components. Increased WISP1 expression is found in lesioned human articular cartilage, and appears epigenetically regulated via DNA methylation. In vitro assays suggest that increased WISP1 is detrimental for cartilage integrity.

Targeted proteomics of hip articular cartilage in OA and fracture patients.

Osteoarthritis (OA) is a common chronic disease, causing joint pain and reduced physical function. OA progresses slowly over a period of several years; to avoid an exacerbation of symptoms, it is critical to able to diagnose the disease as early as possible. The identification of disease-specific biomarkers may enable such an early diagnosis. The aim of this study was to investigate potential biomarkers of cartilage metabolism in OA using a targeted multiplex approach by single reaction monitoring. Intact looking cartilage of femoral heads from patients with OA (n = 9) or femoral neck fractures (n = 12) was examined. Variations and relative quantifications of 35 selected extracellular matrix (ECM) proteins were analyzed using nano-LC coupled to tandem mass spectrometry. Our study showed statistically significantly increased levels of asporin (ASPN), mimecan (MIME), matrilin-3 (MATN3), cartilage intermediate layer protein 2 (CILP-2), collagen VI, collagen II, and collagen III N-propeptide in OA cartilage compared with non-OA cartilage. The other proteins in the protein panel did not appear to be different between the two groups. In conclusion, we identified a number of cartilage matrix proteins which may represent early molecular changes in the OA process and may have potential to predict the development of OA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Shockwave Targeting on Subchondral Bone Is More Suitable than Articular Cartilage for Knee Osteoarthritis.

Our study compared the effects of extracorporeal shockwave therapy (ESWT) on the subchondral bone and the articular cartilage in the treatment of early osteoarthritis (OA) of rat knee. The rats were divided into 5 groups which included Sham group, Meniscus group (ESWT applied on medial meniscus), OA group (arthrotomy and medial menisectomy (MMx) and anterior cruciate ligament transection (ACLT), T(M) group (arthrotomy and MMx and ACLT followed by ESWT on medial tibial subchondral bone) and Articular cartilage group (arthrotomy and MMx and ACLT followed by ESWT on medial articular cartilage). Evaluations included the pathological changes of the synovium, articular cartilage and subchondral bone, and compared with ESWT on the meniscus, medial tibial subchondral bone and articular cartilage. The ESWT (0.25 mJ/mm² and 800 impulses) did not cause any damages on the cartilage of the meniscus and the tissue of the joint when compared with Sham group. Among the treatment of osteoarthritic groups (OA, T(M) and Articular cartilage groups), T(M) group showed significant in pathological examination, micro-CT analysis, cartilage grading score and grading of synovium changes by compared with OA and Articular cartilage groups (P < 0.05) in the treatment of early OA knee. In immunohistochemical analysis, T(M) group significantly increased the expression of TGF-β1 but reduced DMP-1, MMP-13 and ADAMTS-5 in the cartilage by compared with OA group and Articular cartilage group (P < 0.05). Our results showed that subchondral bone was an excellent target than articular cartilage for ESWT on early knee osteoarthritis.

Opportunities of magnetic resonance imaging in diagnosis of microstructural changes of articular cartilage in osteoarthritis

Aim. To estimate the opportunities of proton density-weighed magnetic resonance tomograms in diagnosis of microstructural changes of articular cartilage (AC) in osteoarthritis (OA) on the basis of proton density (PD) variability analyzed.&#x0D; Materials and methods. Sixty two patients with OA and 8 volunteers without OA were examined. All the patients underwent MRI of the knee joints, using tomograph with magnetic field intensity equal to 1.5 tesla. To assess MR images, semiquantitative measurements of articular tissues on the basis of WORMS protocols were used. To estimate the proton density, manual segmentation of PDFS-weighed images of the knee joint medial condyle was implemented. The proton density was estimated, applying 3-D histogram (0–255).&#x0D; Results. At stage I of osteoarthritis, fall in density H+ in the peripheral zone of AC was observed, but it was preserved in the contact part, exposed to maximum statodynamic loadings. At stage II, significant progressing decrease in H+ density peaks in the AC regions, subjected to lesser loads, with preservation of high spectral peaks in the region of elevated friction was stated. Stage III of gonarthrosis was characterized by decrease in H+-spectra as a whole, especially in the loading regions of AC. At stage IV of OA, global reduction in PD intensity was observed along the whole cartilaginous plate surface.&#x0D; Conclusions. The detected patterns of changes in proton density spectra reflect the known degenerative process in AC with osteoarthritis. This property of proton-weight MR-images can be used for assessment of microstructural changes in the articular cartilage with OA.

USP14-mediated IκBα degradation exacerbates NF-κB activation and IL-1β-stimulated chondrocyte dedifferentiation

Osteoarthritis (OA) is an inflammatory joint disease. USP14, a deubiquitinating enzyme critical for ubiquitin-mediated proteasomal protein degradation, is implicated in inflammation regulation. However, its role and mechanism in OA are poorly understood. Here, we report that USP14 is upregulated in OA articular cartilage as well as in chondrocytes treated with IL-1β in vitro. USP14 upregulation depends on NF-κB pathway activation, since inhibition of this pathway by ACHP, a selective inhibitor of IKK-β, abolishes USP14 upregulation. We further show that USP14 in turn exacerbates NF-κB activation through promoting IκBα deubiquitination and degradation. Functionally, USP14 aggravates the dedifferentiation effect of IL-1β on chondrocytes, and NF-κB inhibition remarkably reverses this effect, highlighting an important role of NF-κB in mediating USP14 function. Collectively, our data reveal a previously unidentified feed-forward loop driven by USP14 and NF-κB pathway in promoting the dedifferentiation effect of IL-1β on chondrocytes. This mechanism might offer a useful hint for OA intervention.

Repurposing Human Osteoarthritic Cartilage as a Bone Graft Substitute in an Athymic Rat Posterolateral Spinal Fusion Model.

Spinal fusion involves both endochondral and intramembranous bone formation. We previously demonstrated that endochondral cartilage grafts that were derived from human osteoarthritic (OA) articular cartilage can be used as a bone graft in mouse models. We hypothesized that OA cartilage could also be recycled and repurposed as a bone graft substitute in a posterolateral lumbar spinal fusion model in athymic rats. OA articular cartilage was obtained from the femoral resection of a healthy 60-year-old man undergoing elective total knee arthroplasty. The chondrocytes recovered from this tissue were dedifferentiated in monolayer tissue culture and then transitioned to culture conditions that promote chondrocyte hypertrophy. The resultant cell pellets were then used as bone graft substitute for single-level posterolateral spinal fusion in 5 athymic rats. Decortication alone was used as the control group. Spinal fusion was assessed with manual palpation, micro-computed tomography, and histologic analysis. In the experimental group, micro-computed tomography at 4 and 8 weeks demonstrated bilateral fusion in 4 of 5 animals and unilateral fusion in 1 animal. At 8 weeks, manual palpation and histologic analysis showed direct correlation with the radiographic findings. Animals undergoing decortication alone failed to generate any spinal fusion. The difference in the fusion rate between groups was statistically significant with respect to both unilateral fusion (P = .047) and bilateral fusion (P = .007). In the absence of additional surgically implanted bone graft, hypertrophic chondrocyte grafts are sufficient for generating single-level posterolateral lumbar fusion in athymic rats. This animal study demonstrates that cartilage harvested from OA knees can be used as a bone graft substitute. Commercially available cell-based bone grafts have previously only used mesenchymal stem cells or osteoblast precursor cells.

RNA sequencing data integration reveals an miRNA interactome of osteoarthritis cartilage

ObjectiveTo uncover the microRNA (miRNA) interactome of the osteoarthritis (OA) pathophysiological process in the cartilage.MethodsWe performed RNA sequencing in 130 samples (n=35 and n=30 pairs for messenger RNA (mRNA) and...

Inhibition of YAP with siRNA prevents cartilage degradation and ameliorates osteoarthritis development.

The Hippo/YAP signaling pathway is important for mediating organ size and tissue homeostasis, but its role in osteoarthritis (OA) remains unclear. We aimed to investigate the role of Hippo/YAP signaling pathway in OA development. YAP expression in OA cartilage was assessed by immunohistochemistry, RT-qPCR, and Western blotting. The effects of YAP overexpression or knockdown on gene expression related to chondrocyte hypertrophy induced by IL-1β were examined. The in vivo effects of YAP inhibition were studied. Subchondral bone was analyzed by micro-CT. YAP was increased in mice and human OA articular cartilage and chondrocytes. YAP mRNA expression level was also increased in IL-1β-induced chondrocytes. YAP overexpression resulted in increased expression of catabolic genes in response to IL-1β. Suppression of YAP by siRNA inhibited IL-1β stimulated catabolic genes expression and chondrocytes apoptosis. Intra-articular injection of YAP siRNA ameliorated OA development in mice. Micro-CT results showed the aberrant subchondral bone formation was also reduced. We provided evidence that YAP was upregulated in OA cartilage. Inhibition of YAP using YAP siRNA is a promising way to prevent cartilage degradation in OA. KEY MESSAGES: YAP was upregulated in human and mice osteoarthritis cartilage and chondrocytes. YAP siRNA decreased IL-1β-induced catabolic gene expression. Intra-articular injection of YAP siRNA ameliorated OA development. Intra-articular injection of YAP siRNA reduced aberrant subchondral bone formation.

A Novel High Sensitivity Type II Collagen Blood-Based Biomarker, PRO-C2, for Assessment of Cartilage Formation.

N-terminal propeptide of type II collagen (PIINP) is a biomarker reflecting cartilage formation. PIINP exists in two main splice variants termed as type IIA and type IIB collagen NH2-propeptide (PIIANP, PIIBNP). PIIANP has been widely recognized as a cartilage formation biomarker. However, the utility of PIIBNP as a marker in preclinical and clinical settings has not been fully investigated yet. In this study, we aimed to characterize an antibody targeting human PIIBNP and to develop an immunoassay assessing type II collagen synthesis in human blood samples. A high sensitivity electrochemiluminescence immunoassay, hsPRO-C2, was developed using a well-characterized antibody against human PIIBNP. Human cartilage explants from replaced osteoarthritis knees were cultured for ten weeks in the presence of growth factors, insulin-like growth factor 1 (IGF-1) or recombinant human fibroblast growth factor 18 (rhFGF-18). The culture medium was changed every seven days, and levels of PIIBNP, PIIANP, and matrix metalloproteinase 9-mediated degradation of type II collagen (C2M) were analyzed herein. Serum samples from a cross-sectional knee osteoarthritis cohort, as well as pediatric and rheumatoid arthritis samples, were assayed for PIIBNP and PIIANP. Western blot showed that the antibody recognized PIIBNP either as a free fragment or attached to the main molecule. Immunohistochemistry demonstrated that PIIBNP was predominately located in the extracellular matrix of the superficial and deep zones and chondrocytes in both normal and osteoarthritic articular cartilage. In addition, the hsPRO-C2 immunoassay exhibits acceptable technical performances. In the human cartilage explants model, levels of PIIBNP, but not PIIANP and C2M, were increased (2 to 7-fold) time-dependently in response to IGF-1. Moreover, there was no significant correlation between PIIBNP and PIIANP levels when measured in knee osteoarthritis, rheumatoid arthritis, and pediatric serum samples. Serum PIIBNP was significantly higher in controls (KL0/1) compared to OA groups (KL2/3/4, p = 0.012). The hsPRO-C2 assay shows completely different biological and clinical patterns than PIIANP ELISA, suggesting that it may be a promising biomarker of cartilage formation.

MicroRNA-206 is required for osteoarthritis development through its effect on apoptosis and autophagy of articular chondrocytes via modulating the phosphoinositide 3-kinase/protein kinase B-mTOR pathway by targeting insulin-like growth factor-1.

microRNA (miR) has been shown to be involved in the treatment of diseases such as osteoarthritis (OA). This study aims to investigate the role of miR-206 in regulating insulin-like growth factor-1 (IGF-1) in chondrocyte autophagy and apoptosis in an OA rat model via the phosphoinositide 3-kinase (P13K)/protein kinase B (AKT)-mechanistic target of rapamycin (mTOR) signaling pathway. Wistar rats were used to establish the OA rat model, followed by the observation of histopathological changes, Mankin score, and the detection of IGF-1-positive expression and tissue apoptosis. The underlying regulatory mechanisms of miR-206 were analyzed in concert with treatment by an miR-206 mimic, an miR-206 inhibitor, or small interfering RNA against IGF-1 in chondrocytes isolated from OA rats. Then, the expression of miR-206, IGF-1, and related factors in the signaling pathway, cell cycle, and apoptosis, as well as inflammatory factors, were determined. Subsequently, chondrocyte proliferation, cell cycle distribution, apoptosis, autophagy, and autolysosome were measured. OA articular cartilage tissue exhibited a higher Mankin score, promoted cell apoptotic rate, increased expression of IGF-1, Beclin1, light chain 3 (LC3), Unc-51-like autophagy activating kinase 1 (ULK1), autophagy-related 5 (Atg5), caspase-3, and Bax, yet exhibited decreased expression of miR-206, P13K, AKT, mTOR, and Bcl-2. Besides, miR-206 downregulated the expression of IGF-1 and activated the P13K/AKT signaling pathway. Moreover, miR-206 overexpression and IGF-1 silencing inhibited the interleukins levels (IL-6, IL-17, and IL-18), cell apoptotic rate, the formation of autolysosome, and cell autophagy while promoting the expression of IL-1β and cell proliferation. The findings from our study provide a basis for the efficient treatment of OA by investigating the inhibitory effects of miR-206 on autophagy and apoptosis of articular cartilage in OA via activating the IGF-1-mediated PI3K/AKT-mTOR signaling pathway.

Activation of NF-κB in Synovium versus Cartilage from Patients with Advanced Knee Osteoarthritis: A Potential Contributor to Inflammatory Aspects of Disease Progression.

The aim was to assess the activation and association of the NF-κB system across synovial membrane (SM) and articular cartilage (AC) in patients with knee osteoarthritis (OA) and ascertain its potential effects on catabolic mediator expression in advanced OA. SM and AC were obtained from 40 OA patients undergoing total knee arthroplasty and from 19 postmortem control subjects. NF-κB subunit RelA in nuclear and cytosolic fractions and NF-κB1-DNA binding in nuclear extracts was assessed by ELISA, whereas NFKB1, RELA, IL-8, IL-6, and MMP3 gene expression were analyzed by reverse transcriptase-quantitative PCR in tissues. We observed higher SM nuclear RelA protein levels and upregulated NF-κB1-DNA binding in OA patients compared with postmortem controls. However, in AC, lower nuclear RelA levels were observed compared with cytosolic extracts in patients. Nuclear RelA levels correlated positively with NF-κB1-DNA binding in SM and AC in patients. SM RELA and MMP3 mRNA levels were upregulated, whereas IL-8 and IL-6 as well as AC RELA were downregulated in patients compared with controls. In SM, nuclear RelA levels correlated positively with MMP3 gene expression in patients. A negative correlation was observed between SM nuclear RelA levels and AC NF-κB1-DNA binding, and SM nuclear NF-κB1-DNA binding correlated negatively with AC MMP3 and NFKB1 mRNA levels in patients. These findings highlight NF-κB-triggered cross-talk and feedback mechanisms between SM and AC in OA. Further, our findings strongly support a role for an activated NF-κB system in the transcriptional mechanism of inflammatory processes, especially in SM of patients with advanced OA.

Quantification of solute diffusivity in osteoarthritic human femoral cartilage using correlation spectroscopy.

Osteoarthritis is a chronic joint disease characterized by articular cartilage degeneration, pain, and disability. As an avascular tissue, the movement of water and solutes through the tissue is critical to cartilage health and function, and early changes in solute diffusivity due to micro-scale changes in the properties of cartilage's extracellular matrix might precede clinical symptoms. A diagnostic technique for quantifying alteration to the diffusive environment of cartilage that precedes macroscopic changes may allow for the earlier identification of osteoarthritic disease, facilitating earlier intervention strategies. Toward this end, we used two confocal microscopy-based correlation spectroscopy techniques, fluorescence correlation spectroscopy and raster image correlation spectroscopy, to quantify the diffusion of two small solutes, fluorescein and 3k dextran, within human osteoarthritic articular cartilage. Our goal was to determine if these relatively simple optical correlation spectroscopy techniques could detect changes in solute diffusivity associated with increasing cartilage damage as assessed by International Cartilage Repair Society scoring guidelines, and if these measures are correlated with mechanical and compositional measures of cartilage health. Our data show a modest, yet significant increase in solute diffusivity and cartilage permeability with increasing osteoarthritis score (grades 0-2), with a strong correlation between diffusion coefficients, permeability, and cartilage composition. The described correlation spectroscopy techniques are quick, simple, and easily adapted to existing laboratory workflow and equipment. Furthermore, the minimal solute concentrations and laser powers required for analysis, combined with recent advances in arthroscopic microscopy, suggest correlation spectroscopy techniques as translational candidates for development into early OA diagnosis tools. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3256-3267, 2018.

MicroRNAs and Osteoarthritis.

An imbalance in gene expressional events skewing chondrocyte anabolic and catabolic pathways toward the latter causes an aberrant turnover and loss of extracellular matrix proteins in osteoarthritic (OA) articular cartilage. Thus, catabolism results in the elevated loss of extracellular matrix proteins. There is also evidence of an increase in the frequency of chondrocyte apoptosis that compromises the capacity of articular cartilage to undergo repair. Although much of the fundamental OA studies over the past 20 years identified and characterized many genes relevant to pro-inflammatory cytokines, apoptosis, and matrix metalloproteinases (MMPs)/a disintegrin and metalloproteinase with thrombospondin motif (ADAMTS), more recent studies focused on epigenetic mechanisms and the associated role of microRNAs (miRs) in regulating gene expression in OA cartilage. Thus, several miRs were identified as regulators of chondrocyte signaling pathways, apoptosis, and proteinase gene expression. For example, the reduced expression of miR-146a was found to be coupled to reduced type II collagen (COL2) in OA cartilage, whereas MMP-13 levels were increased, suggesting an association between MMP-13 gene expression and COL2A1 gene expression. Results of these studies imply that microRNAs could become useful in the search for diagnostic biomarkers, as well as providing novel therapeutic targets for intervention in OA.

Fourier transform infrared spectroscopic imaging application for multi-stage discrimination in cartilage degeneration

Fourier transform infrared spectroscopic imaging (FTIRI) technique can be used to obtain rich information about the chemical components in biological tissue such as articular cartilage, by employing quantitative chemometrics methods. In this study, the imaging technique was used for spectroscopic imaging on cartilage sections. The support vector machine discriminant analysis (SVM-DA) was then employed in imaging data analysis to distinguish among healthy and osteoarthritic (OA) articular cartilages at different degeneration stages for the first time. Briefly, the infrared spectra were extracted from the FTIR images and imported into Unscrambler software for the SVM-DA model construction and prediction. When the 3rd-polynomial kernel function was chosen as the kernel function and the parameters C in each range of 2782.5–10000, 2.3714–10 and 0.0032–0.01, respectively, and the corresponding optimal G was equal to 0.1, 1 and 10, the healthy, OA-8W (8 week after surgery) and OA-2Y (2 years after surgery) cartilage samples were effectively differentiated by the SVM-DA method with high accuracy of 100% for the training set and 86.67% for the prediction group. FTIRI with the use of chemometrics (SVM-DA) may become an effective method to distinguish multi-stage tissue degradation in the future.

Changes in the size of hyperthrophic chondrocytes in articular cartilage in osteoarthritis

Purpose: Osteoarthritis (OA) is a disease characterized by degradation of articular cartilage, osteophyte formation, subchondral sclerosis and synovial proliferation, which results in the loss of joint function and disability. Osteoporosis (OP) is a disorder characterized by reduced bone mass, leading to diminished physical bone strength and increased susceptibility to fracture. In a combined model of OP followed by a destabilization-induced OA in rabbits, we have described microstructural impairment of subchondral bone withincreased remodelling that aggravates cartilage damage. Accordingly, numerous alterations in structural and biomechanical properties have been described in the articular cartilage of different experimental models of low bone mass induced by ovariectomy (OVX). Our aim was to associate the severity of OA and the size of the hyperthropic chondrocytes in articular cartilage in a combined model of OPOA. Methods: New Zealand female rabbits were randomly assigned to four groups: healthy rabbits (control group, n=8), osteoporotic (OP group, n=7), osteoarthritic (OA group, n=8) and OA with previous osteoporosis rabbits (OPOA group, n=8). OP was induced by OVX and administration of metilprednisolone (1mg/kg/day) during six weeks. After this period, OA was induced by anterior cruciate ligand transection and the disease developed over 6 weeks. All animals were euthanized and tibias, femurs, synovium and serum samples were collected. 17-beta estradiol levels were analyzed for OP validation. Macroscopic evaluation and Mankin score were done to analyze joint damage. TRAP staining was performed in the joint to analyze bone resorption. Finally, chondrocyte size was measured in articular cartilage, and we did a correlation between the chondrocyte size and the Mankin score. To carry out statistic studies we used a Kruskal-Wallis test following by a Mann Whitney test. Results: OP induced-rabbits showed lower levels of 17-beta estradiol (pg/ml) than the others (Healthy: 44±8, OP: 26±3, OA: 40±10, OPOA: 28±6, p<0.05 OP and OPOA vs Healthy). Macroscopic evaluation reflected significant differences between control and the rest of the groups, and between OA and OPOA faced to OP (Healthy: 0.25±0.10, OP: 2.0±0.5, OA: 4.6±0.2, OPOA: 4.5±0.2, p<0.05 all groups vs Healthy, and OA-OPOA vs OP). Mankin score showed significant more severity damage in osteoarthritic groups than control rabbits, and OPOA more than OP group (Healthy: 1.6±0.2. OP: 5.0±1.5, OA: 6.0±0.6, OPOA: 7.5±1.3, p<0.05 vs Control). TRAP staining showed that OA and OPOA groups had more number of stained cells than Control and OP rabbits (Healthy: 8.5+2.6, OP: 7.6±3.0, OA: 43±11, OPOA: 80±18). Osteoarthritic groups had larger chondrocyte size than control and OP rabbits, and OPOA chondrocytes were slightly larger than OA chondrocytes. (Healthy: 131±7, OP: 152±12, OA: 187±15, OPOA: 234±16, p<0.005 OA - OPOA vs Healthy, p<0.05 OPOA vs OA). Finally, it was significantly the correlation between Mankin score and chondrocyte size(p<0.05, r= 0.4314). Conclusions: Our results suggest that OPOA model presents more severity than OA in joint damage, and this fact correlated with chondrocyte size in articular cartilage, whose are associated in osteoarthritis with the severity of the disease, being bigger in OPOA rabbits than OA group.

Effect of Jiangu granule on the expression of AQP3 in articular cartilage of rats with knee osteoarthritis

Objective To investigate the effect and significance of Jiangu granule on the expression of aquaporin 3 (AQP3) in articular cartilage of knee osteoarthritis (OA) rats. Methods Sprague-Dawley (SD) rats were randomly divided into sham operation group, model group, and Jiangu granule treatment group. The treatment group was divided into Jiangu granule high dose, medium dose, and low dose groups, with 12 rats in each group. The osteoarthritis model was made by injecting 4% papain and 0.03 mol/L L-cysteine mixture into the knee joint. Sham-operated group and model group received normal feeding every day. Treatment group (high, medium, and low dose groups), the next day after the completion of the model, were given different dose Jiangu granule by gavage twice a day for 4 weeks. After treatment, the rats were executed uniformly, using general optical microscope and the pathological section of histology to observe the articular cartilage damage. The expression of AQP3 in articular cartilage of rats was detected by real time polymerase chain reaction (RT-PCR) and Western blot. Results The articular cartilage destruction of Jiangu granule treatment group was significantly less than that of the model group (P<0.05). The mRNA and protein expression levels of AQP3 in model group was significantly higher than that in the sham operation group (P<0.05). OA rats with Jiangu granule after 4 weeks treatment, the mRNA and protein expression levels of AQP3 in articular cartilage were decreased significantly. Jiangu granule in each sub group relative to the model group had statistical significance (P<0.05), and the high dose group was decreased significantly. Conclusions Jiangu granule can reduce the expressions of AQP3 in OA articular cartilage of rats and alleviate the swelling of joints, which may have protective effects on articular cartilage. Key words: Osteoarthritis, knee/ZY; Drugs, chinese herbal/AD; Cartilage, articular/PA/ME; Aquaporin 3/ME; Rats

Pulsed gradient stimulated echo (PGStE) NMR shows spatial dependence of fluid diffusion in human stage IV osteoarthritic cartilage.

PurposeHuman osteoarthritic (OA) articular cartilage was investigated with spatially resolved pulsed gradient stimulated echo (PGStE) NMR using strong gradients. In this study, the diffusivity of fluid and biopolymer was characterized as a function of depth within human OA cartilage cores.MethodsOne dimensional (1D) spatially resolved diffusion profiles were measured for human OA cartilage using a standard pulsed gradient stimulated echo (PGStE) sequence with the addition of a read imaging gradient. Low gradient values (0.05 to 1.5 Tm−1) were used to measure fluid motion and high gradients (2.50 to 17.81 Tm−1) enabled analysis of biopolymer motion. Structural damage to cartilage was simulated using either salt or collagenase.ResultsThese data demonstrate that fluid diffusion is sensitive to salt treatment and collagenase digestion, while biopolymer diffusion is sensitive only to collagenase digestion. Biopolymer and fluid diffusion are donor specific for human OA cartilage samples.ConclusionThese data support that fluid diffusion is sensitive to the structure of cartilage while biopolymer diffusion is sensitive to the molecular weight of the biopolymers. The results show that diffusion of fluid and biopolymers in articular cartilage are sensitive to OA and provide complimentary information. Magn Reson Med 80:1170–1177, 2018. © 2018 International Society for Magnetic Resonance in Medicine.