Cartilage Biomarkers Research Articles

Associations between circulating S100A8/A9 and knee symptoms, joint cartilage defects and cartilage biomarkers in patients with knee osteoarthritis

Associations between circulating S100A8/A9 and knee symptoms, joint cartilage defects and cartilage biomarkers in patients with knee osteoarthritis

Repeatability and discrimination validity of cartilage imaging biomarkers for experimental medicine studies of knee osteoarthritis

PURPOSE The utility of magnetic resonance imaging (MRI) quantitative imaging biomarkers (QIBs) of cartilage in experimental medicine studies of potential disease modifying osteoarthritis treatments (DMOATs) is uncertain due to the small sample sizes and short follow-up involved. To be relevant to such studies, candidate QIBs must demonstrate acceptable repeatability, discriminative ability and responsiveness. The purpose of this study was to evaluate test-retest repeatability and discriminative ability of 4 cartilage QIBs at the knee (thickness, T1rho, T2 and delayed gadolinium enhanced MRI of cartilage [dGEMRIC]) to assess their utility in experimental medicine studies. METHODS We imaged 9 participants with mild-moderate knee osteoarthritis (OA), characterised by radiographs with medial tibiofemoral predominant disease and Kellgren-Lawrence grades 2-3, and 4 healthy volunteers (HVs) matched for age, sex and body mass index. Participants were imaged at baseline and 1 month. MR studies were performed on a 3T system (MR 750, GE Healthcare) and were split into 2 sessions. The first MR session included a 3-dimensional spoiled gradient echo (3D SPGR) sequence and T1rho and T2 mapping sequences. At the end of this session, we administered an intravenous gadolinium based contrast agent (Dotarem, Guerbet LLC) at double dose (0.2 mmol/kg). Participants then performed 10 minutes of exercise on a stationary cycle to facilitate contrast penetration into the joint for dGEMRIC. The second MR session began 90 minutes following injection of contrast agent and consisted of T1 mapping using a variable flip angle technique. MR pulse sequence details are provided in table 1. We performed surface based analysis of cartilage parameters using Stradwin software (http://mi.eng.cam.ac.uk/~rwp/stradwin). In brief, this consists of semi-automated thickness measurement on 3D SPGR images, with generation of accurate inner and outer cartilage surfaces. Following rigid registration of the compositional (T1rho, T2, dGEMRIC) data to the 3D SPGR images, the same surfaces were used to sample the compositional data. This analysis pipeline allows each parameter to be measured at ~5,000 surface vertices per participant. We assessed overall (pooled OA and HV data) test-retest repeatability by calculating the root-mean-square coefficient of variation (RMS-CV) and the smallest detectable change (SDC) for each parameter. We assessed overall discriminative validity by estimating effect sizes for the difference in the mean value of each parameter in OA participants and HVs. We also mapped the test-retest errors and mean difference in each parameter between groups onto a representative surface for each cartilage region. RESULTS Participant characteristics are provided in table 2. RMS-CVs, SDCs and effect size estimates are provided in table 3. Overall test-retest RMS-CV values ranged from 2.5% (T1rho) to 10.3% (dGEMRIC). The largest overall effect size was demonstrated for dGEMRIC (-1.3, 90% confidence interval [CI] -2.3 to -0.2), followed by thickness (-0.67, 90% CI -1.5 to 0.3), T1rho and T2 (both 0.61, 90% CI -0.4 to 1.5). Mapping of test-retest errors and between-group differences to a representative surface revealed substantial spatial heterogeneity in these metrics for all parameters (figure 1). This suggests that surface based approaches may offer improved sensitivity over traditional region of interest based measurements. CONCLUSION This study demonstrates that cartilage QIBs may be useful in experimental medicine studies of knee osteoarthritis. Statistical approaches reflecting the spatial heterogeneity of changes in cartilage should be used to provide an indication of where significant results are located, not just whether an average value is significantly different. Future work will evaluate responsiveness of these cartilage QIBs.

The selective cathepsin K inhibitor MIV-711 attenuates joint pathology in experimental animal models of osteoarthritis

BackgroundMIV-711 is a highly potent and selective cathepsin K inhibitor. The current article summarizes the therapeutic effects of MIV-711 on joint pathology in rabbits subjected to anterior cruciate ligament transection (ACLT), and the prophylactic effects on joint pathology in dogs subjected to partial medial meniscectomy, two surgical models of osteoarthritis (OA).MethodsStarting 1 week after surgery, rabbits were dosed daily via oral gavage with either MIV-711 or vehicle (n = 7/group) for 7 weeks. The four treatment groups were: (1) sham + vehicle; (2) ACLT + vehicle; (3) ACLT + MIV-711, 30 µmol/kg and (4) ACLT + MIV-711, 100 µmol/kg. Subchondral bone and articular cartilage structures were assessed by µCT, histomorphometry, and scoring. Dogs subjected to partial medial meniscectomy received either MIV-711 (30 µmol/kg) or vehicle (n = 15/group) via oral gavage once daily, starting 1 day before meniscectomy, for 28 days. Cartilage degradation was assessed at the macroscopic and microscopic levels. The exposures of MIV-711 were assessed in both studies and biomarkers reflecting bone resorption (HP-1 in rabbits, CTX-I in dogs) and cartilage degradation (CTX-II) were measured.ResultsIn ACLT rabbits, MIV-711 decreased HP-1 levels by up to 72% (p < 0.001) and CTX-II levels by up to 74% (p < 0.001) compared to ACLT vehicle controls. ACLT surgery significantly reduced the total thickness of the subchondral bone plate and reduced trabecular bone volume in the femur and tibia. These effects were reversed by MIV-711. ACLT resulted in cartilage thickening, which was attenuated by MIV-711. MIV-711 did not affect osteophyte formation or Mankin scores. In dogs, MIV-711 reduced CTX-I and CTX-II levels by 86% (p < 0.001) and 80% (p < 0.001), respectively. Synovial CTX-II levels were reduced by 55–57% (p < 0.001) compared to baseline. MIV-711-treated animals had 25–37% lower macroscopic scores in the femur condyles and 13–33% lower macroscopic scores in the tibial plateaus.ConclusionsMIV-711 prevents subchondral bone loss and partially attenuates cartilage pathology in two animal models of OA. These beneficial effects of MIV-711 on joint pathology are observed in conjunction with decreases in bone and cartilage biomarkers that have been shown to be clinically attainable in human. The data support the further development of MIV-711 for the treatment of OA.

Dickkopf-related protein 1 and gremlin 1 show different response than frizzled-related protein in human synovial fluid following knee injury and in patients with osteoarthritis

To explore the involvement of the wingless-type MMTV integration site (WNT) and bone morphogenetic protein (BMP) antagonists dickkopf-related protein 1 (DKK1), frizzled-related protein (FRZB) and gremlin 1 (GREM1) in knee injury and osteoarthritis (OA). The antagonists were immunoassayed in synovial fluid from a cross-sectional cohort of nine knee healthy reference subjects, patients with recent (0-77 days, n=158) or old (1-37 years, n=50) knee injuries, and OA (n=22). Cartilage (ARGS-aggrecan, cartilage oligomeric matrix protein and C2C type II collagen) and other biomarkers were assessed in synovial fluid in a subset of samples. Statistical analysis was by Kendall's tau (τ) correlation, Mann-Whitney U test, and linear regression analysis. Compared to references, median concentration of GREM1 (but not DKK1 and FRZB) was elevated 1.5-fold immediately after injury, and FRZB was reduced 1000-folds in OA. All three antagonists decreased with increasing time after injury as well as with increasing age, but the temporal change after injury was less accentuated for FRZB (peaked 8-22 days after injury) compared to that of DKK1 and GREM1 (peaked immediately after injury). In the recent injury group, there was a correlation between GREM1 and DKK1 (τ=0.172); FRZB concentrations correlated with concentrations of cartilage biomarkers (τ between 0.257 and 0.369), while DKK1 and GREM1 were inversely correlated (τ between -0.177 and -0.217) with these markers. Our results indicate separate roles for the antagonists, where DKK1 and GREM1 had similarities in response to injury and in OA, with a different response for FRZB.

A cross sectional study of bone and cartilage biomarkers: correlation with structural damage in rheumatoid arthritis

ABSTRACTThe aim of our study was to assess the relationship between bone and cartilage remodeling biomarkers and joint damage in Rheumatoid Arthritis (RA), and to detect whether they have the capacity to predict the progression of joint disease assessment by computed tomography (CT) erosion score. We analyzed 65 female patients with established RA in our Rheumatology Department. Serum levels of bone and cartilage markers were measured: osteocalcin (OC), N-propeptide of type I collagen (PINP), collagen type I and II, C-telopeptide (CTX I, CTX-II) and cartilage oligomeric matrix protein (COMP). Radiography of both wrist and MCP joints were available. Two expert-readers independently scored articular damage and progression using the High-resolution low dose CT scan in a blinded fashion. 65 female patients with established RA with a median age of 44 years were included. The median disease-duration was two years and the median (Disease activity score) DAS 28 score at 4.46 [2.65–7.36]. The percentage of patient with low disease activity was 13.8%, while 55.4 and 30.8% for those with moderate and high disease activity respectively. The resorption bone markers were high in active versus non-active RA. Wrist and MCP erosion scores were also associated with RA activity. Our study shows that biomarkers of bone and cartilage collagen breakdown were related to specific joint erosion in RA and could predict subsequent radiographic damage in RA. Further larger scale longitudinal studies maybe needed to confirm our data.

ANTI-HEPATOTOXIC AND SYNERGISTIC EFFECTS OF SESAME OIL WITH METHOTREXATE IN ADJUVANT INDUCED ARTHRITIS

Methotrexate (MTX) is the first-line agent for rheumatoid arthritis(RA) treatment although it causes hepatotoxicity leading to poorcompliance to therapy. Sesame oil is unique due to its unusually highoxidative stability and anti-inflammatory property that attributedmainly to the presence of
-tocopherol and anti-oxidative sesamelignans. These components give sesame oil extraordinary highoxidative stability and anti-inflammatory property. The present studyaimed to investigate the anti-hepatotoxic and therapeutic potential ofsesame oil alone or in combined therapy with MTX on RA rat model.Assessment of RA performed by measuring paw volume, rheumatoidfactor and anti-cycliccitrullinated peptide antibody. Biomarkers ofcartilage degeneration (MMP-3) and synthesis, (IGF-1), inflammatorymediators (TNF-
, IL-6, NO), anti-inflammatory mediators(IL-10)and oxidative stress were estimated. MTX mono-therapy wereenhanced hepatotoxicity but concomitant administration with sesameoil was able to ameliorating RA biomarker and led to an increase itseffectiveness without hepatotoxicity. Therefore combined therapy ofMTX with sesame oil may lead to synergistic anti-arthritic action withfewer side effects of MTX on liver.

Effects of scaffold microstructure and low intensity pulsed ultrasound on chondrogenic differentiation of human mesenchymal stem cells.

The effects of low intensity pulsed ultrasound (LIPUS) on proliferation and chondrogenic differentiation of human mesenchymal stem cells (hMSCs) seeded on 3D printed poly-(ethylene glycol)-diacrylate (PEG-DA) scaffolds with varying pore geometries (square and hexagonal channels) were investigated. The scaffold with square pores resulted in higher hMSC growth and chondrogenic differentiation than a solid or a hexagonally porous scaffold. The optimal LIPUS parameters at 1.5 MHz were found to be 100 mW/cm2 and 20% duty cycle. LIPUS stimulation increased proliferation by up to 60% after 24 hr. For chondrogenesis, we evaluated key cartilage biomarkers abundant in cartilage tissue; glycosaminoglycan (GAG), type II collagen and total collagen. LIPUS stimulation enhanced GAG synthesis up to 16% and 11% for scaffolds with square and hexagonal patterns, respectively, after 2 weeks. Additionally, type II collagen production increased by 60% and 40% for the same patterns, respectively under LIPUS stimulation after 3 weeks. These results suggest that LIPUS stimulation, which has already been approved by FDA for treatment of bone fracture, could be a highly efficient tool for tissue engineering in combination with 3D printing and hMSCs to regenerate damaged cartilage tissues.

Sensitivity of serum concentration of cartilage biomarkers to 21‐days of bed rest

Immobilization independently from injury can cause altered cartilage biomarker concentration. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1465-1471, 2018.

Relationship between weight loss in obese knee osteoarthritis patients and serum biomarkers of cartilage breakdown: secondary analyses of a randomised trial.

To explore effects of weight loss and maintenance on serum cartilage biomarkers denaturation neoepitope for Collagen2 (Coll2-1) and Fibulin3 fragment (Fib3-2), as well as correlations between Coll2-1 and Fib3-2 and symptomatic improvement, in a knee osteoarthritis (KOA) population. 192 obese KOA patients followed a 16 week weight loss intervention and 52 weeks weight maintenance (ClinicalTrials.gov identifier: NCT00655941). Assessments were at 0, 8, 16 and 68 weeks. Serum Coll2-1 and Fib3-2 were determined with ELISA, and symptoms by the Knee Osteoarthritis Outcome Score (KOOS) questionnaire. Changes from week 0 and association between changes from baseline in body weight and Coll2-1, Fib3-2, and the 5 KOOS domains were assessed at all time points. Coll2-1 changes from baseline showed a decrease at week 8 (P=0.0002), no change at week 16 (P=0.49), and an increase at week 68 (P=0.036). Fib3-2 showed an increase from baseline at week 8 (P=0.0015) and 16 (P<0.0001), but none at week 68 (P=0.23). No statistically significant correlations were found between changes in body weight and Coll2-1 and Fib3-2 at any time point (r<0.05; P>0.49). At all time-points there were significant positive correlations between changes from baseline in Coll2-1 and in KOOSSports/Recreation (week 8, 16, 68: r=0.17; P=0.03; r=0.16; P=0.04; and r=0.17; P=0.04, respectively). The clinical improvement after a substantial weight loss and weight maintenance in KOA patients was not associated with decrease in markers of cartilage breakdown Coll2-1 or Fib3-2, even with indications of a slightly negative effect.

Changes in Cartilage Biomarker Levels During a Transcontinental Multistage Footrace Over 4486 km

Background: Cartilage turnover and load-induced tissue changes are frequently assessed by quantifying concentrations of cartilage biomarkers in serum. To date, information on the effects of ultramarathon running on articular cartilage is scarce. Hypothesis: Serum concentrations of cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP)–1, MMP-3, MMP-9, COL2-3/4C long mono (C2C), procollagen type II C-terminal propeptide (CPII), and C2C:CPII will increase throughout a multistage ultramarathon. Study Design: Descriptive laboratory study. Methods: Blood samples were collected from 36 runners (4 female; mean age, 49.0 ± 10.7 years; mean body mass index, 23.1 ± 2.3 kg/m2 [start] and 21.4 ± 1.9 kg/m2 [finish]) before (t0) and during (t1: 1002 km; t2: 2132 km; t3: 3234 km; t4: 4039 km) a 4486-km multistage ultramarathon. Serum COMP, MMP-1, MMP-3, MMP-9, C2C, and CPII levels were assessed using commercial enzyme-linked immunosorbent assays. Linear mixed models were used to detect significant changes in serum biomarker levels over time with the time-varying covariates of body weight, running speed, and daily running time. Results: Serum concentrations of COMP, MMP-9, and MMP-3 changed significantly throughout the multistage ultramarathon. On average, concentrations increased during the first measurement interval (MI1: t1-t0) by 22.5% for COMP (95% CI, 0.29-0.71 ng/mL), 22.3% for MMP-3 (95% CI, 0.24-15.37 ng/mL), and 95.6% for MMP-9 (95% CI, 81.7-414.5 ng/mL) and remained stable throughout MI2, MI3, and MI4. Serum concentrations of MMP-1, C2C, CPII, and C2C:CPII did not change significantly throughout the multistage ultramarathon. Changes in MMP-3 were statistically associated with changes in COMP throughout the ultramarathon race (MMP-3: Wald Z = 3.476, P = .001). Conclusion: Elevated COMP levels indicate increased COMP turnover in response to extreme running, and the association between load-induced changes in MMP-3 and changes in COMP suggests the possibility that MMP-3 may be involved in the degradation of COMP. Clinical Relevance: These results suggest that articular cartilage is able to adapt even to extreme physical activity, possibly explaining why the risk of degenerative joint disease is not elevated in the running population.

Platelet-rich plasma induces post-natal maturation of immature articular cartilage and correlates with LOXL1 activation

Platelet-rich plasma (PRP) is used to stimulate the repair of acute and chronic cartilage damage even though there is no definitive evidence of how this is achieved. Chondrocytes in injured and diseased situations frequently re-express phenotypic biomarkers of immature cartilage so tissue maturation is a potential pathway for restoration of normal structure and function. We used an in vitro model of growth factor-induced maturation to perform a comparative study in order to determine whether PRP can also induce this specific form of remodeling that is characterised by increased cellular proliferation and tissue stiffness. Gene expression patterns specific for maturation were mimicked in PRP treated cartilage, with chondromodulin, collagen types II/X downregulated, deiodinase II and netrin-1 upregulated. PRP increased cartilage surface cell density 1.5-fold (P < 0.05), confirmed by bromodeoxyuridine incorporation and proportionate increases in proliferating cell nuclear antigen gene expression. Atomic force microscopy analysis of PRP and growth factor treated cartilage gave a 5-fold increase in stiffness correlating with a 10-fold upregulation of lysyl oxidase like-1 gene expression (P < 0.001). These data show PRP induces key aspects of post-natal maturation in immature cartilage and provides the basis to evaluate a new biological rationale for its activity when used clinically to initiate joint repair.

Association among changes in cartilage biomarker levels during a transcontinental multistage footrace over 4486 km

Association among changes in cartilage biomarker levels during a transcontinental multistage footrace over 4486 km

Serological biomarkers detect active joint destruction and inflammation in patients with haemophilic arthropathy

Progressive arthropathy caused by recurrent joint bleeds is a severe complication in haemophilia. We investigated whether biomarkers of cartilage and bone degradation, and inflammation were altered in haemophilia patients and whether these biomarkers could identify haemophilia patients with arthropathy. Serum from 35 haemophilia patients with varying degrees of arthropathy and 43 age- and gender-matched control subjects were analysed. Biomarkers of cartilage degradation (C2M, COMP, CTX-II, ADAMTS5), cartilage formation (PRO-C2), bone formation (PINP), bone resorption (CTX-I) and inflammation (hsCRP, CRPM) were measured by ELISA. Arthropathy was assessed by radiological evaluation (Pettersson score) and physical examination (Gilbert score). In patients with haemophilia, cartilage degradation, measured by C2M, CTX-II and COMP, was increased by 25% (P < 0.05) compared with control subjects. Levels of the cartilage degradation enzyme, ADAMTS5, were 10% lower in haemophilia patients (P < 0.05). Bone formation (PINP) was reduced by 25% (P < 0.05) in haemophilia patients, whereas bone resorption (CTX-I) was increased by 30% (P < 0.001). Acute inflammation (hsCRP) was increased by 50% (P < 0.01), whereas chronic inflammation (CRPM) was decreased by 25% (P < 0.0001). The hsCRP/CRPM ratio was 60% higher (P < 0.001) in haemophilia patients relative to control subjects. A biomarker panel combining C2M, CRPM, and ADAMTS5 could distinguish haemophilia patients from control subjects with 85.3% accuracy (P < 0.0001). We found no strong correlation between biomarkers and radiological and physical examination of the joint. Biomarkers detect increased cartilage and bone degradation, and altered inflammatory activity in haemophilia patients with arthropathy. These biomarkers could potentially be used to identify patients with progressing joint disease.

Acute mobilization and migration of bone marrow-derived stem cells following anterior cruciate ligament rupture.

Little is known regarding acute local and systemic processes following anterior cruciate ligament (ACL) rupture. No study has elucidated whether bone marrow-derived mesenchymal stem cells (MSCs) are mobilized into circulation and recruited to the injured joint. In Part 1, Lewis rats were randomized to noninvasive ACL rupture (Rupture) or non-injured (Control) (n=6/group). After 72h, whole blood MSC concentration was assessed using flow cytometry. Synovial fluid and serum were assayed for stromal cell-derived factor (SDF)-1α and cartilage degeneration biomarkers, respectively. In Part 2, 12 additional rats were randomized and intravenously-injected with fluorescently-labeled allogenic MSCs. Cell tracking was performed using longitudinal, invivo and exvivo near-infrared (NIR) imaging and histology. Synovium SDF-1α and interleukin (IL)-17A immunostaining was performed. Serum was assayed for SDF-1α and 29 other cytokines. In Part 1, there was a significant increase in MSC concentration and synovial fluid SDF-1α in Rupture. No differences in cartilage biomarkers were observed. In Part 2, Rupture had significantly higher NIR signal at 24, 48, and 72h, indicating active recruitment of MSCs to the injured joint. Exvivo cell tracking demonstrated MSC localization in the synovium and myotendinous junction (MTJ) of the quadriceps. Injured synovia exhibited increased synovitis grade and higher degree of IL-17A and SDF-1α immunostaining. ACL rupture induced peripheral blood mobilization of MSCs and migration of intravenously-injected allogenic MSCs to the injured joint, where they localized in the synovium and quadriceps MTJ.

Serum Cartilage Biomarkers and Shoulder Instability.

Differences in cartilage biomarkers have been noted in patients with anterior cruciate ligament tears, but little is known about any similar relationship with shoulder instability. This study evaluated the relationship between serum cartilage biomarkers and shoulder instability. The authors present a prospective cohort study of young athletes followed from 2006 to 2010. A nested case-control analysis was conducted within this cohort to evaluate the association between preinjury collagen type II cleavage (a marker for type II collagen cleavage) and procollagen II carboxy propeptide (a marker of cartilage synthesis) and the subsequent likelihood of shoulder instability during the 4-year follow-up period. Preinjury collagen type II cleavage and procollagen II carboxy propeptide levels in 51 subjects who had shoulder instability were compared with levels in 210 subjects without documented anterior cruciate ligament or shoulder instability (control group) with commercially available enzyme-linked immunosorbent assay kits. Mean preinjury collagen type II cleavage levels in patients who subsequently had shoulder instability were significantly lower than those in the control group (73.91 vs 79.24 pg/mL, P=.03). No significant difference was found in preinjury procollagen II carboxy propeptide levels compared with the control group (359.94 vs 396.37, P=.24). This study is the first to examine the relationship between baseline collagen biomarkers and subsequent shoulder instability. The finding of lower baseline collagen type II cleavage levels in patients with subsequent shoulder instability may represent a genetic predisposition or a compensatory mechanism by which cartilage degradation is decreased in those who are more likely to have instability. [Orthopedics. 2017; 40(1):34-36.].

Evaluation of Two Protocols Using Autologous Conditioned Serum for Intra-articular Therapy of Equine Osteoarthritis—A Pilot Study Monitoring Cytokines and Cartilage-Specific Biomarkers

We hypothesised that shorter treatment intervals of intraarticular autologous conditioned serum (ACS) injections would more beneficially affect the synovial fluid (SF) concentrations of IL-1ra, IL-1β and cartilage biomarkers, compared with the traditional weekly treatment intervals in joints suffering from natural OA. In a randomised comparative study, 12 horses with OA were allocated to two groups (n = 6). The horses in group 1 received three intraarticular ACS injections at weekly intervals, whereas the horses in group 2 received three intraarticular ACS injections at two-day intervals. The levels of IL-1ra, IL-1β, CPII, C12C and CS 846 were determined in SF before and after ACS treatment using commercially available ELISA kits. The SF IL-1ra concentration 1 hour and 4 hours after ACS injection was significantly increased compared to baseline levels and decreased back to it within 48 hours. Comparing the SF IL-1ra, IL-1β, C12C, CS 846 and CP II levels before and 42 days after ACS treatment, group 2 showed a significant decrease in all parameters and an approximation on the levels in normal joints. These results indicate that the long-time effect of an ACS treatment given at two-day intervals is characterized by decreased SF IL1ra, IL-1β, C12C, CP II and CS 846 concentrations, which might indicate an improvement in joint inflammation and cartilage degrading processes . Further investigations with greater sample sizes have to prove if the two-day treatment interval is preferable to the widely used treatment protocol of weekly intraarticular ACS injections.

Low intensity pulsed ultrasound and lipid-coated microbubbles enhance chondrogenesis of human mesenchymal stem cells in 3D bioprinted scaffolds

Annually, over 6 million people visit hospitals in the United States for issues arising from cartilage damages due to osteoarthritis, acute trauma, rheumatoid arthritis, and sports injury. Articular cartilage is a tissue notoriously hard to regenerate. The objective of this study is to investigate the possibility of facilitating cartilage regeneration using low intensity pulsed ultrasound (LIPUS) stimulation and microbubbles. We have investigated effects of lipid-coated microbubbles (MB) prepared in-house along with LIPUS on proliferation and chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in a novel 3D printed poly(ethylene glycol) diacrylate (PEG-DA) hydrogel scaffold. Our results demonstrate for the first time that LIPUS stimulation in the presence of 0.5% (v/v) MB greatly enhances MSC proliferation for up to 40% after 5 days of treatment. This value is only 18% when excited with LIPUS alone. Furthermore, we optimized acoustic parameters such as excitation intensity, frequency and pulse repetition period for chondrogenic differentiation studies. Synthesis of type II collagen and GAG, which are two key cartilage biomarkers, increased 78% and 17%, respectively, in the presence of LIPUS and MBs, when compared to the controls.

Utility of circulating serum miRNAs as biomarkers of early cartilage degeneration in animal models of post-traumatic osteoarthritis and inflammatory arthritis

The purpose of this study was to determine if serum microRNA (miRNA) signatures were biomarkers of early cartilage degeneration in preclinical mouse models of post-traumatic osteoarthritis (OA) and inflammatory arthritis. Cartilage degeneration was induced in 10-12 week old male C57BL6 mice by destabilization of the medial meniscus (DMM) or intra-articular injection of methylated-bovine-serum-albumin (AIA), with sham-operated or saline-injected control animals (n=6/treatment/time). Total serum RNA and knee joints were isolated at 1, 4 and 16 weeks post-induction. Cartilage degeneration was scored histologically. Serum miRNA expression profiling was performed using Agilent microarrays and validated by qPCR. DMM-operated and AIA mice had characteristic cartilage degeneration (proteoglycan loss, chondrocyte hypertrophy, structural damage), that increased significantly with time compared with controls, and with distinct temporal differences between arthritis models. However, expression profiling revealed no statistically significant dysregulation of serum miRNAs between AIA vs saline-injected or DMM vs sham-operated control mice at the critical early disease stages. The inability to detect DMM or AIA serum miRNA signatures compared with controls was not due to the insensitivity of the expression profiling approach since significant changes were observed in miRNA expression between the arthritis models and between time points. While distinct patterns of progressive cartilage degradation were induced in the arthritis models, we were unable to identify any serum miRNAs that were significantly dysregulated in early stages of disease compared with controls. This suggests circulating serum miRNAs may not be useful as cartilage biomarkers in distinguishing the early or progressive stages of arthritis cartilage degeneration.

Magnetic Resonance Imaging of Cartilage Contact and Bound Water in ACL-Deficient and ACL Reconstructed Knees

Objectives:Osteoarthritis (OA) is common following ACL-reconstructive (ACLR) surgery (6). The cause of early OA is not understood, but theories have focused on osteochondral damage at the time of injury (2) and abnormal joint mechanics following surgical repair (7). In this study, we investigate the inter-relationship of cartilage mechanics and biomarkers of OA in both ACL-deficient (ACLD) and ACLR knees. Our approach employs a novel dynamic MR sequence to measure joint mechanics (3) and the recently developed mcDESPOT to assess regional variations in water bound to proteoglycan (PG) (5). We hypothesize that bound water will be diminished in the cartilage of ACLD knees and, after surgery, will continue to adapt in a manner that reflects altered cartilage loading. This abstract presents initial observations on a cross-section of healthy, ACLD and ACLR knees.Methods:The dominant knees of 8 healthy controls, ACLD knees of 5 patients and ACLR knees of 8 patients were imaged in a 3 T MRI scanner (Table). Controls had no history of pain, injury, or surgery to their knee. Patients had no additional ligament injury and no meniscal damage. ACLD subjects were imaged prior to reconstructive surgery. Femoral and tibial cartilage were segmented from MR images and cartilage thickness was calculated. The mcDESPOT sequence provided a fraction map of water bound to PG (Fpg). Subjects flexed their knee against an inertial load at 0.5 Hz, while a SPGR-VIPR sequence continuously acquired volumetric data. Kinematics were obtained using model tracking of the dynamic images (3). Cartilage was registered to the bone segments for all frames, and contact patterns were characterized by the proximity between surfaces. Spatial representations of tibial cartilage contact, thickness and Fpg were co-registered for each subject.Results:Our initial images suggest lower Fpg values in ACLD knees, primarily on the posterior-lateral tibia. This is also observed in ACLR knees, with additional evidence of diminished Fpg on the weight-bearing medial tibia. Contact patterns were altered in both groups. ACLD tended to exhibit increased contact on the posterior lateral tibia and anterior contact in the medial tibia. Contact differences in the ACLR knees were more subtle, but tended to show a posterior-lateral shift on the medial tibia when compared to control knees (Figure). These initial observations support our hypotheses that cartilage composition may be altered in ACLD knees and continues to adapt following ACLR. While contact in ACLR knees appears to be restored close to the healthy condition, we observed a residual shift in the medial plateau. Interestingly, this shift corresponds with a decrease in PG content not observed in ACLD knees. Loss of PG occurs early in OA, prior to any morphological changes (1, 4). Decreased PG content was also observed in ACLD and ACLR knees in the posterio-lateral tibia, consistent with observations of edema and cartilage damage following an ACL injury (2).Conclusion:Initial observations of our novel dynamic and quantitative MR images suggests altered cartilage composition due to both injury and abnormal mechanics following surgical repair.

Potential biomarkers of haemophilic arthropathy: correlations with compatible additive magnetic resonance imaging scores.

Although biomarkers are useful diagnostic tools to assess joint damage in osteoarthritis and rheumatoid arthritis, few data exist for biomarkers of haemophilic arthropathy. To evaluate the association between biomarkers and compatible additive magnetic resonance imaging (MRI) scores in patients with severe haemophilia A. Patients aged 12-35 years with no history of factor VIII (FVIII) inhibitors were enrolled in a controlled, cross-sectional, multinational investigation. Patients received primary or secondary prophylaxis or on-demand treatment with FVIII and underwent MRI on four joints (two ankles, two knees). Soluble biomarkers of cartilage and bone degradation, inflammation, and angiogenesis were assessed (serum levels of C-terminal telopeptides of type I collagen [CTX-I], cartilage oligomeric matrix protein [COMP], chondroitin-sulphate aggrecan turnover 846 epitope [CS846], tissue inhibitor of metalloproteinase 1 [TIMP-1]; plasma levels of vascular endothelial growth factor [VEGF], matrix metalloproteinases 3 and 9 [MMP3, MMP9]). Relationships between biomarkers and MRI scores were evaluated using Spearman rank correlation. Biomarkers were assessed in 117 of 118 per-protocol patients. Mean and median CTX-I, COMP, TIMP-1, MMP3, MMP9, and VEGF values were within normal ranges (reference range not available for CS846 in healthy volunteers). No correlations between biomarkers and MRI scores were found, with the exception of CS846, which showed significant correlation in a subgroup of 22 on-demand patients (r = 0.436; P = 0.04). Compatible additive MRI scores showed no clear correlations with any of the potential biomarkers for haemophilic arthropathy in the overall population. CS846 levels were significantly correlated with MRI scores in patients treated on demand.