The evolving role of biomarkers for osteoarthritis

Differential Expression of Fibrinogen Alpha and Its Potential Involvement in Osteoarthritis Pathogenesis

The deterioration of cartilage tissue and other joint components composed of synovial tissue is a defining characteristic of osteoarthritis (OA) disease. Because of the lack of understanding of the underlying cause and important molecular pathways, there are currently no effective diagnostic or treatment methods for OA. The purpose of the study is to find a specific protein biomarker with high sensitivity and specificity in order to understand the pathophysiology of the disease and the underlying molecular pathways. We examined plasma samples of matched age and sex from OA patients (n = 150) and healthy controls (HC) (n = 70) to find proteins that were differentially expressed and validated by western blotting, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and immunofluorescence. The results of western blotting demonstrated that the expression level of the fibrinogen alpha (FGA) protein was higher in plasma samples of osteoarthritis (OAPL) (p = 0.0343), and the ROC (receiver operating characteristic curve) curve supported the high sensitivity (95.22%) and specificity (74%) of FGA in OA plasma compared to healthy controls. FGA protein was detected to be deposited in the synovial tissue of OA patients (p = 0.0073). By activating the Toll-like receptor (TLR-4) receptor pathway in PBMCs (p = 0.04) and synovial tissue, FGA protein may be involved in the molecular mechanism of OA pathogenesis. Our findings collectively suggested that FGA, which is significantly expressed in OA plasma, synovial tissue, and PBMCs and is connected to the disease's advancement through the TLR-4 receptor, may serve as a diagnostic or disease-evolving tool for OA.

Evaluation of mechanistic serum and urine biomarkers for secondary osteoarthritis associated with developmental dysplasia of the hip

Objective

Determine measurable differences for mechanistic urine and serum biomarkers in patients with developmental dysplasia of the hip (DDH) prior to, and following, secondary hip osteoarthritis (OA) when compared to controls.

Design

Urine and serum were collected from individuals with developmental dysplasia of the hip (n = 39), prior to (Pre-OA DDH, n = 32) and following diagnosis of secondary hip OA (Post-OA DDH, n = 7), age-matched Pre-OA controls (n = 35), and age-matched Post-OA controls (n = 12). Samples were analyzed for protein biomarkers with potential for differentiation of hip status through a Mann-Whitney U test with a Benjamini-Hochberg correction.

Results

Several interleukin and degradation related proteins were found to be differentially expressed when comparing DDH-related hip status prior to and following diagnosis of hip OA. In addition, MCP-1 and TIMP-1 were significantly different between younger and older patients in the control cohorts.

Conclusion

These results provide initial evidence for serum and urine protein biomarkers that define clinically relevant stages of symptomatic DDH and its progression to secondary hip osteoarthritis categorized by known mechanisms of disease.

Level of evidence

III.

Different changes in the biomarker C-terminal telopeptides of type II collagen (CTX-II) following intra-articular injection of high molecular weight hyaluronic acid and oral non-steroidal anti-inflammatory drugs in patients with knee osteoarthritis: a multi-center randomized controlled study

OBJECTIVES

We previously reported, based on a multicenter randomized-control study, that the efficacy of intra-articular injections of hyaluronic acid (IA-HA) was not inferior to that of oral non-steroidal anti-inflammatory drugs (NSAIDs) in patients with knee osteoarthritis (OA). However, the molecular effects on the pathophysiology of knee OA remain unclear. C-terminal telopeptides of type II collagen (CTX-II) is reported to primarily originate from the interface between articular cartilage and subchondral bone, which is a site of potential remodeling in OA. We performed a predefined sub-analysis of the previous study to compare the changes of urinary CTX-II (uCTX-II) in response to IA-HA to those in response to NSAID for knee OA.

DESIGN

A total of 200 knee OA patients were registered from 20 hospitals and randomized to receive IA-HA (2,700 kDa HA, 5 times at 1-week intervals) or NSAID (loxoprofen sodium, 180 mg/day) for 5 weeks. The uCTX-II levels were measured before and after treatment.

RESULTS

The uCTX-II levels were significantly increased by IA-HA treatment (337.7 ± 193.8 to 370.7 ± 234.8 ng/μmol Cr) and were significantly reduced by NSAID treatment (423.2 ± 257.6 to 370.3 ± 250.9 ng/μmol Cr). The %changes of uCTX-II induced by IA-HA (11.6 ± 29.5%) and NSAID (-9.0 ± 26.7%) was significantly different (between-group difference: 20.6, 95% confidence intervals: 10.6 to 30.6).

CONCLUSIONS

While both IA-HA and NSAID improved symptoms of knee OA, uCTX-II levels were increased by IA-HA and reduced by NSAIDs treatment, suggesting these treatments may improve symptoms of knee OA through different modes of action.

Effect of Transcutaneous Vagus Nerve Stimulation in Erosive Hand Osteoarthritis: Results from a Pilot Trial

Beyond its effect on vegetative functions, the activation of the vagus nerve inhibits inflammation and reduces pain signaling. The aim of this open-label pilot study was to determine the efficacy and tolerance of transcutaneous auricular VNS (taVNS) on erosive hand osteoarthritis (EHOA) symptoms. Symptomatic EHOA patients with hand pain VAS ≥ 40/100 mm and ≥1 interphalangeal swollen joint(s) were included. The taVNS was performed for 4 weeks using an auricular electrode applied one hour per day and connected to a TENS device with pre-established settings. Clinical efficacy was evaluated by changes between baseline and at 4 weeks with hand pain VAS and the functional index FIHOA score, using a Wilcoxon t-test. The treatment tolerance was also evaluated. Eighteen patients (median age 69 years old, 83% women) were analyzed. At baseline, hand pain VAS was 60 mm [IQR 50; 78.2] and FIHOA 15 [10.7; 20.2]. After 4 weeks, taVNS significantly reduced hand pain VAS, with a median decrease of 23.5 mm [7.7; 37.2] (p = 0.001), as well as FIHOA, with a median decrease of 2 points [0.75; 5.2] (p = 0.01). No serious adverse events were reported. One patient stopped taVNS because of auricular discomfort. This first proof-of-concept trial indicated that taVNS is feasible and may decrease joint inflammation and clinical symptoms in EHOA, arguing for a randomized controlled study versus sham stimulation.

Efficacy and safety of celecoxib combined with JOINS in the treatment of degenerative knee osteoarthritis: study protocol of a randomized controlled trial

Background

The aim of this study will be to investigate the therapeutic effect and safety of non-steroidal anti-inflammatory drugs (NSAIDs) along with symptomatic slow-acting drugs for the treatment of osteoarthritis (SYSADOA), JOINS tablets, for degenerative knee osteoarthritis (OA) treatment and to determine the analgesic and anti-inflammatory effects of the combination therapy. In addition, we will investigate whether JOINS treatment alone after NSAID and JOINS combination treatment is effective in relieving and maintaining knee OA symptoms.

Methods

This study will be a prospective, randomized, double-blind endpoint study design. All patients will be randomly assigned to either intervention (celecoxib+JOINS) or control (celecoxib+placebo) groups. In Part 1, the intervention group will be administered celecoxib once a day and JOINS three times a day for a total of 12 weeks. In the control group, celecoxib will be administered once a day and JOINS placebo three times a day for a total of 12 weeks. In Part 2, JOINS alone and JOINS placebo alone will be administered for an additional 24 weeks in both groups, respectively. The primary endpoint will be the amount of change during the 12 weeks as assessed using the Western Ontario and McMaster Universities Osteoarthritis Index total score compared with baseline. The secondary endpoint will be the amount of change at 1, 4, 12, 24, and 36 weeks from the baseline for pain visual analog scale, Brief Pain Inventory, Short Form Health Survey-36 and biomarkers.

Results

The trial was registered with Clinical-Trials.gov (NCT04718649). The clinical trial was also registered on Clinical Research Information Service (CRIS) with the trial registration number KCT0005742.

Conclusions

The combination treatment of the most commonly used SYSADOA drug, JOINS, and selective COX-2 inhibitor celecoxib as the representative NSAID for knee OA treatment, can be compared with celecoxib alone treatment to determine the safety or therapeutic effect.

Data Integration Reveals the Potential Biomarkers of Circulating MicroRNAs in Osteoarthritis

The abnormal expression of circulating miRNAs (c-miRNAs) has become an emerging field in the development of miRNAs-based diagnostic and therapeutic tools for human diseases, including osteoarthritis (OA). OA is the most common form of arthritis leading to disability and a major socioeconomic burden. The abnormal expression of miRNAs plays important roles in the pathogenesis of OA. Unraveling the role of miRNAs in the pathogenesis of OA will throw light on the potential for the development of miRNAs-based diagnostic and therapeutic tools for OA. This article reviews and highlights recent advances in the study of miRNAs in OA, with specific demonstration of the functions of miRNA, especially c-miRNA, in OA pathogenesis as well as its potential implication in the treatment of OA. Based on a systematic literature search using online databases, we figured out the following main points: (1) the integrative systematic review of c-mRNAs and its target genes related to OA pathogenesis; (2) the potential use of c-miRNAs for OA diagnosis purposes as potential biomarkers; and (3) for therapeutic purposes, and we also highlight certain remedies that regulate microRNA expression based on its target genes.

The value of serum total oxidant to the antioxidant ratio as a biomarker of knee osteoarthritis

BACKGROUND & AIMS

The balance between oxidants and antioxidants is known as oxidative balance, which is impaired in many disease conditions such as osteoarthritis (OA). In this study, we aimed to evaluate this balance in OA patients through the evaluation of the oxidant to the antioxidant ratio.

MATERIALS AND METHODS

A total of 62 knee OA patients and 20 age, sex, and BMI-matched healthy controls were included in this cross-sectional study. Serum total oxidant status (TOS) and total antioxidant capacity (TAC) were evaluated using the oxidation-reduction colorimetric assay. The TOS to TAC ratio (TOS/TAC) was evaluated as an estimate of the oxidant to antioxidant balance.

RESULTS

The mean TOS was 14.2 ± 2 μM in the healthy controls and 23.3 ± 7 μM in the OA patients (p < 0.001). The mean TAC was 38.8 ± 6.6 μM in the healthy subjects and 35.8 ± 12 μM in the OA patients (p = 0.33). The mean TOS/TAC was 0.38 ± 0.09 in the healthy subjects and 0.72 ± 0.3 in the OA patients (p < 0.0001). TOS/TAC value was capable of distinguishing OA patients from healthy controls with the sensitivity and specificity of 87.1% and 80%, respectively (p < 0.001). At the cutoff value of 0.46, positive TOS/TAC (>0.46) was identified in 100% of grade I patients, whereas it was negative in 27.3%, 16.7%, and 16.7% of grades II, III, and IV, respectively (p = 0.039).

CONCLUSION

In the knee OA, an equation of the serum TOS to TAC could be a good representative of oxidative balance than each component individually.

Comparison of blood platelet distribution width and neutrophil-lymphocyte ratio in patients with different grades of knee osteoarthritis

OBJECTIVE

The aim of this study was to compare platelet distribution width (PDW) and neutrophil to lymphocyte ratio (NLR) values in mild-to-moderate and severe knee osteoarthritis (OA).

METHODS

This was a retrospective study of patients with knee OA according to the Kellgren-Lawrence (KL) grading system. Of 465 patients, 231 were excluded (62 due to not meeting the inclusion criteria and 169 due to the lack of simultaneous haemogram and radiographic evaluations). Demographic characteristics and PDW and NLR values were recorded. The patients were then divided into two groups: KL grade 1-3 (mild-to-moderate OA) and KL grade 4 (severe OA).

RESULTS

In severe knee OA patients, blood PDW (13.44 ± 2.58, p= 0.01) and NLR values (2.16 ± 0.84, p= 0.04) were elevated as compared with those in mild-to-moderate knee OA patients. Blood PDW and NLR values of ⩾ 12.5 and ⩾ 2.1, respectively, were taken as cut-offs based on a receiver operating characteristics (ROC) curve analysis. In the ROC curve analysis, blood NLR ⩾ 2.1 had 60% sensitivity and 64.8% specificity, and PDW ⩾ 12.5 had 61% sensitivity and 58% specificity in predicting severe knee OA. In a univariate analysis, age (p< 0.001), PDW ⩾ 12.5 (p= 0.029) and blood NLR ⩾ 2.1 (p= 0.030) emerged as significant predictors of the severe knee OA.

CONCLUSION

The results suggested that the blood PDW and NLR are novel inflammatory markers that can predict the radiographic severity of knee OA in clinical practice.

[Effect of icariin on serum bone turnover markers expressions and histology changes in mouse osteoarthritis model]

Objective

To investigate the effects of icariin (ICA) on serum bone turnover markers expressions and histological changes of cartilage and subchondral bone in mouse osteoarthritis (OA) model.

Methods

Eighty 8-week-old male C57BL/6J mouse were randomly divided into 8 groups ( n=10). The OA model was established by anterior cruciate ligament transaction (ACLT). Group A: sham operation/early-stage normal saline administration; group B: sham operation/early-stage ICA administration; group C: ACLT/early-stage normal saline administration; group D: ACLT/early-stage ICA administration; group E: sham operation/late-stage normal saline administration; group F: sham operation/late-stage ICA administration; group G: ACLT/late-stage normal saline administration; group H: ACLT/late-stage ICA administration. Each animal received either ACLT or simply opening joint capsule, respectively. For groups B and D, ICA was given by gavage [10 mg/(kg·day)] on the first day after ACLT. For groups F and H, ICA was given with the same volume at 4 weeks after operation. The blood serum of the mouse was collected and prepared at 8 weeks after operation. Serum bone turnover markers and cytokines, including C-telopeptide of type I collagen (CTX), osteocalcin (OC), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and IL-1β, were measured by ELISA. Tissue samples from the knee were stained by alcian blue/hematoxylin & orange G (AB/H&OG). Histological changes of cartilage and subchondral bone were observed and evaluated by Osteoarthritis Research Society International (OARSI) scoring system.

Results

Comparison between each group with early-stage administration (groups A, B, C, and D): Compared with groups A and B, the levels of CTX and OC in group C were significantly reduced ( P<0.05); the levels of IL-6, TNF-α, and IL-1β and OARSI score was significantly increased ( P<0.05). Compared with group C, the levels of CTX and OC in group D were significantly increased ( P<0.05); the level of IL-6 was significantly reduced ( P<0.05); the levels of TNF-α and IL-1β were not changed ( P>0.05), and OARSI score was significantly reduced ( P<0.05). Histological observation showed that the tibial cartilage loss was significantly improved. Comparison between each group with late-stage administration (groups E, F, G, and H): Compared with groups E and F, the levels of CTX and OC in group G were significantly reduced ( P<0.05); the levels of IL-6, TNF-α, and IL-1β and OARSI score were significantly increased ( P<0.05). Compared with group G, the level of CTX in group H were increased ( P<0.05); the levels of OC, IL-6, TNF-α, and IL-1β and OARSI score were not changed ( P>0.05). Histological observation showed that the tibial cartilage loss had no changes after late-stage ICA administration.

Conclusion

ICA plays protective effects on subchondral bone, hyaline, and calcified cartilage. Meanwhile, ICA can improve bone remodeling in subchondral bone of OA to some extent. The consistent changes of serum bone markers and pathological morphology suggest that early intervention of ICA on OA is more effective.

Interplay of Inflammatory Mediators with Epigenetics and Cartilage Modifications in Osteoarthritis

Osteoarthritis (OA), a degenerative disease of diarthrodial joints, is influenced by mechanical and inflammatory factors with aging, obesity, chronic injuries, and secondary diseases thought to be major factors driving the process of articular cartilage degeneration. Chondrocytes, the cellular component of cartilage, reside in an avascular environment and normally have limited potential to replicate. However, extrinsic factors such as injury to the joint or intrinsic alterations to the chondrocytes themselves can lead to an altered phenotype and development of OA. Synovial inflammation is also a pivotal element of the osteoarthritic, degenerative process: influx of pro-inflammatory cytokines and production of matrix metalloproteinases accelerate advanced cellular processes such as synovitis and cartilage damage. As well as a genetic input, recent data have highlighted epigenetic factors as contributing to disease. Studies conducted over the last decade have focused on three key aspects in OA; inflammation and the immune response, genome-wide association studies that have identified important genes undergoing epigenetic modifications, and finally how chondrocytes transform in their function during development and disease. Data highlighted here have identified critical inflammatory genes involved in OA and how these factors impact chondrocyte hypertrophy in the disease. This review also addresses key inflammatory factors in synovial inflammation, epigenetics, and chondrocyte fate, and how agents that inhibit epigenetic mechanisms like DNA methylation and histone modifications could aid in development of long-term treatment strategies for the disease.

Single intra-articular injection of fluvastatin-PLGA microspheres reduces cartilage degradation in rabbits with experimental osteoarthritis

Statins are cholesterol-lowering drugs that inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, a rate-limiting enzyme of the mevalonate pathway. The anti-inflammatory effect of statins has been reported in recent years. The present study investigated therapeutic effects of the local administration of statin in osteoarthritis (OA). We assessed clinically used statins and selected fluvastatin for further experimentation, as it showed potent anabolic and anti-catabolic effects on human OA chondrocytes. To achieve controlled intra-articular administration of statin, we developed an intra-articular injectable statin using poly(lactic-co-glycolic acid) (PLGA) as a drug delivery system (DDS). The release profile of the statin was evaluated in vitro. Finally, therapeutic effects of fluvastatin-loaded PLGA microspheres (FLU-PLGA) were tested in a rabbit OA model. Rabbit knees were divided into four subgroups: group 1-A, PLGA-treated group; group 1-B, PLGA contralateral saline control group; group 2-A, FLU-PLGA-treated group; and group 2-B, FLU-PLGA contralateral saline control group. Histological analysis 5 weeks after intra-articular injection revealed that OARSI scores were lower in group 2-A. No significant differences in OARSI scores were observed between groups 1-A, 1-B, and 2-B. This study indicates that a single intra-articular injection of fluvastatin-loaded PLGA microspheres could be a novel therapeutic approach for treating patients with OA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2465-2475, 2017.

Comparative study of CTX-II, Zn2+, and Ca2+ from the urine for knee osteoarthritis patients and healthy individuals

The aim of the study was to explore the relationship between the concentration of C-telopeptide fragments of type II collagen (CTX-II), Zn, and Ca in urine and knee osteoarthritis (KOA).Eighty-two patients with KOA and 20 healthy volunteers were enrolled. Anteroposterior and lateral position x-rays of knee joints were collected. The images were classified according to Kellgren-Lawrence radiographic grading criterion. The patients were divided into group grade I, group grade II, group grade III, and grade IV. The concentration of CTX-II in the urine was detected by enzyme-linked immunosorbent assay. The concentration of Zn and Ca in urine was detected by inductively coupled plasma atomic emission spectrometry.Compared with the healthy individuals, the concentration of CTX-II was significantly higher in KOA patients. The concentration of CTX-II in KOA patients from high to low was as follows: group IV, group III, group II, and group I. There was no significant difference between group I and healthy individuals. The concentration of Zn and Ca in urine of KOA patients was higher than that in healthy individuals. There was no difference in each KOA group.The concentration of CTX-II is instrumental to diagnose the progress of KOA. The concentration of Zn and Ca in urine is helpful for early diagnosis of KOA.

Blood Transcriptional Signatures for Disease Progression in a Rat Model of Osteoarthritis

Biomarkers of osteoarthritis (OA) that can accurately diagnose the disease at the earliest stage would significantly support efforts to develop treatments for prevention and early intervention. We have sought to determine the time course of alterations in peripheral blood gene expression profile associated with the development of OA. Blood samples were collected from a tail vein of individual rats with monosodium iodoacetate- (MIA-) induced OA (2, 14, 21, and 28 days after the treatment). We used whole-genome microarrays to reveal OA-related transcriptional alterations of 72 transcripts. Three main groups of coexpressed genes revealed diverse time-dependent profiles of up- and downregulation. Functional links that connect expression of the gradually downregulated genes to the G13 signaling pathway were indicated. The mRNA abundance levels of the identified transcripts were further analyzed in publicly available gene expression dataset obtained from a GARP study cohort of OA patients. We revealed three-gene signature differentially expressed in both rat and human blood (TNK2, KCTD2, and WDR37). The alterations in expression of the selected transcripts in peripheral blood samples of the patients indicate heterogeneity of the OA profiles potentially related to disease progress and severity of clinical symptoms. Our study identifies several potential stage-specific biomarkers of OA progression.

Serum snoRNAs as biomarkers for joint ageing and post traumatic osteoarthritis

The development of effective treatments for the age-related disease osteoarthritis and the ability to predict disease progression has been hampered by the lack of biomarkers able to demonstrate the course of the disease. Profiling the expression patterns of small nucleolar RNAs (snoRNAs) in joint ageing and OA may provide diagnostic biomarkers and therapeutic targets. This study determined expression patterns of snoRNAs in joint ageing and OA and examined them as potential biomarkers. Using SnoRNASeq and real-time quantitative PCR (qRT-PCR) we demonstrate snoRNA expression levels in murine ageing and OA joints and serum for the first time. SnoRNASeq identified differential expression (DE) of 6 snoRNAs in young versus old joints and 5 snoRNAs in old sham versus old experimental osteoarthritic joints. In serum we found differential presence of 27 snoRNAs in young versus old serum and 18 snoRNAs in old sham versus old experimental osteoarthritic serum. Confirmatory qRT-PCR analysis demonstrated good correlation with SnoRNASeq findings. Profiling the expression patterns of snoRNAs is the initial step in determining their functional significance in ageing and osteoarthritis, and provides potential diagnostic biomarkers and therapeutic targets. Our results establish snoRNAs as novel markers of musculoskeletal ageing and osteoarthritis.

Identification of ageing-associated naturally occurring peptides in human urine

To assess normal and pathological peptidomic changes that may lead to an improved understanding of molecular mechanisms underlying ageing, urinarypeptidomes of 1227 healthy and 10333 diseased individuals between 20 and 86 years of age were investigated. The diseases thereby comprised diabetes mellitus, renal and cardiovascular diseases. Using age as a continuous variable, 116 peptides were identified that significantly (p < 0.05; |ρ|≥0.2) correlated with age in the healthy cohort. The same approach was applied to the diseased cohort. Upon comparison of the peptide patterns of the two cohorts 112 common age-correlated peptides were identified. These 112 peptides predominantly originated from collagen, uromodulin and fibrinogen. While most fibrillar and basement membrane collagen fragments showed a decreased age-related excretion, uromodulin, beta-2-microglobulin and fibrinogen fragments showed an increase. Peptide-based in silico protease analysis was performed and 32 proteases, including matrix metalloproteinases and cathepsins, were predicted to be involved in ageing. Identified peptides, predicted proteases and patient information were combined in a systems biology pathway analysis to identify molecular pathways associated with normal and/or pathological ageing. While perturbations in collagen homeostasis, trafficking of toll-like receptors and endosomal pathways were commonly identified, degradation of insulin-like growth factor-binding proteins was uniquely identified in pathological ageing.

In vitro effects of platelet-rich gel supernatants on histology and chondrocyte apoptosis scores, hyaluronan release and gene expression of equine cartilage explants challenged with lipopolysaccharide

Background

Platelet-rich plasma (PRP) preparations are a common treatment in equine osteoarthritis (OA). However, there are controversies regarding the ideal concentration of platelets and leukocytes in these biological substances necessary to induce an adequate anti-inflammatory and anabolic response in articular cartilage. The aims were to study the influence of leukocyte- and platelet-rich gel (L-PRG) and pure platelet-rich gel (P-PRG) supernatants on the histological changes of cartilage, the degree of chondrocyte apoptosis, the production of hyaluronan (HA) and the gene expression of nuclear factor kappa beta (NFkβ), matrix metalloproteinase 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4), collagen type I alpha 1 (COL1A1), collagen type II alpha 1 (COL2A1) and cartilage oligomeric matrix protein (COMP) in normal cartilage explants (CEs) challenged with lipopolysaccharide (LPS).

Results

Overall, 25 % L-PRG supernatant (followed in order of importance by, 50 % P-PRG, 25 % P-PRG and 50 % L-PRG) represented the substance with the most important anti-inflammatory and anabolic effect. 25 % P-PRG supernatant presented important anabolic effects, but it induced a more severe chondrocyte apoptosis than the other evaluated substances.

Conclusions

25 % L-PRG supernatant presented the best therapeutic profile. Our results demonstrate that the biological variability of PRP preparations makes their application rather challenging. Additional in vivo research is necessary to know the effect of PRP preparations at different concentrations.

Oral Resveratrol Prevents Osteoarthritis Progression in C57BL/6J Mice Fed a High-Fat Diet

The effects of resveratrol on osteoarthritis (OA) pathogenesis have been demonstrated in vitro and in animal models employing intra-articular injections. However, the potential for oral resveratrol supplements to mediate protective effects on OA have not been examined. Therefore, the aim of the present study was to investigate the potential anti-OA effects of oral resveratrol on mice fed a high-fat diet (HFD). C57BL/6J male mice were fed either a standard diet or a HFD, and a subset of the latter also received varying doses of resveratrol. Twelve weeks later, all of the animals were sacrificed and knee joints were evaluated with histological, immunohistochemical, and TUNEL analyses. Mice that received a HFD had significantly greater body weights than the control mice and also exhibited features consistent with knee OA. The mice that received a HFD in combination with low, intermediate, or high doses of resveratrol were only slightly heavier than the control mice at the end of 12 weeks. Quantitative histological assessments indicated that resveratrol treatment partly recovered joint structure in the mice that received a HFD, while high doses of resveratrol prevented the degradation of type II collagen into C-telopeptide of type II collagen (CTX-II) and retained type II collagen expression in cartilage. Furthermore, TUNEL analyses revealed a reduction in chondrocyte apoptosis in the resveratrol-treated mice compared with the HFD mice. Thus, oral resveratrol appears to exert anti-OA effects in a mouse model of HFD-induced OA, thereby highlighting the potential preventive and therapeutic value of administering resveratrol for obesity-associated OA.

Docosahexenoic acid treatment ameliorates cartilage degeneration via a p38 MAPK-dependent mechanism

Osteoarthritis (OA) is a common chronic inflammatory disease, characterized by cartilage degradation. The aberrant expression of matrix metalloproteinase-13 (MMP-13) plays a vital role in the pathogenesis of OA. The anti‑inflammatory property of docosahexenoic acid (DHA) was previously revealed and showed that DHA retards the progress of many types of inflammatory disease. To evaluate the prophylactic function of DHA in OA, the effect of DHA on cartilage degeneration was assessed in interleukin‑1β (IL‑1β) stimulated human chondrosarcoma SW1353 cells or a rat model of adjuvant‑induced arthritis (AIA). The safe concentration range (0‑50 µg/ml in vitro) of DHA was determined by flow cytometry and MTT assay. The inhibitory effects of DHA on MMP‑13 mRNA and protein expression were confirmed by RT‑qPCR, ELISA and western blotting. Furthermore, findings of an in vivo study showed that DHA can increase the thickness of articular cartilage and decrease MMP‑13 expression in cartilage matrix in a rat AIA model. We also revealed the mechanism by which DHA ameliorates cartilage degeneration from OA. The DHA-mediated inhibition of MMP‑13 expression was partially attributed to the inactivation of the p38 mitogen‑activated protein kinases pathway by suppressing p‑p38 in IL-1β-stimulated SW1353 cells and a rat AIA model. Our findings suggested that DHA is a promising therapeutic agent that may be used for the prevention and treatment of OA.

Repositioning Bevacizumab: A Promising Therapeutic Strategy for Cartilage Regeneration

Drug discovery and development has been garnering an increasing trend of research due to the growing incidence of the diverse types of diseases. Recently, drug repositioning, also known as drug repurposing, has been emerging parallel to cancer and tissue engineering studies. Drug repositioning involves the application of currently approved or even abandoned drugs as alternative treatments to other diseases or as biomaterials in other fields including cell therapy and tissue engineering. In this review, the advancement of the antiangiogenesis drugs that were used as treatment for cancer and other diseases, with particular focus on bevacizumab, will be described. This will include an overview of the nature and progression of osteoarthritis (OA), one of the leading global degenerative diseases that cause morbidity, and the development of its therapeutic strategies. In addition, this will also feature the nonsteroidal anti-inflammatory drugs that are commonly prescribed for OA and the benefits of repositioning bevacizumab as alternative treatments for other diseases and as biomaterials for cartilage regeneration. To date, a few number of studies, employing different modes of administration and varying dosages in diverse animal models, have shown that bevacizumab can be used as a signal and can promote both in vitro and in vivo cartilage regeneration. However, other antiangiogenesis drugs and their effects in chondrogenesis and cartilage regeneration are also worth investigating.

Low- Versus High-Intensity Plyometric Exercise During Rehabilitation After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Plyometric exercise is used during rehabilitation after anterior cruciate ligament (ACL) reconstruction to facilitate the return to sports participation. However, clinical outcomes have not been examined, and high loads on the lower extremity could be detrimental to knee articular cartilage.

PURPOSE

To compare the immediate effect of low- and high-intensity plyometric exercise during rehabilitation after ACL reconstruction on knee function, articular cartilage metabolism, and other clinically relevant measures.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Twenty-four patients who underwent unilateral ACL reconstruction (mean, 14.3 weeks after surgery; range, 12.1-17.7 weeks) were assigned to 8 weeks (16 visits) of low- or high-intensity plyometric exercise consisting of running, jumping, and agility activities. Groups were distinguished by the expected magnitude of vertical ground-reaction forces. Testing was conducted before and after the intervention. Primary outcomes were self-reported knee function (International Knee Documentation Committee [IKDC] subjective knee form) and a biomarker of articular cartilage degradation (urine concentrations of crosslinked C-telopeptide fragments of type II collagen [uCTX-II]). Secondary outcomes included additional biomarkers of articular cartilage metabolism (urinary concentrations of the neoepitope of type II collagen cleavage at the C-terminal three-quarter-length fragment [uC2C], serum concentrations of the C-terminal propeptide of newly formed type II collagen [sCPII]) and inflammation (tumor necrosis factor-α), functional performance (maximal vertical jump and single-legged hop), knee impairments (anterior knee laxity, average knee pain intensity, normalized quadriceps strength, quadriceps symmetry index), and psychosocial status (kinesiophobia, knee activity self-efficacy, pain catastrophizing). The change in each measure was compared between groups. Values before and after the intervention were compared with the groups combined.

RESULTS

The groups did not significantly differ in the change of any primary or secondary outcome measure. Of interest, sCPII concentrations tended to change in opposite directions (mean ± SD: low-intensity group, 28.7 ± 185.5 ng/mL; high-intensity group, -200.6 ± 255.0 ng/mL; P = .097; Cohen d = 1.03). Across groups, significant changes after the intervention were increased the IKDC score, vertical jump height, normalized quadriceps strength, quadriceps symmetry index, and knee activity self-efficacy and decreased average knee pain intensity.

CONCLUSION

No significant differences were detected between the low- and high-intensity plyometric exercise groups. Across both groups, plyometric exercise induced positive changes in knee function, knee impairments, and psychosocial status that would support the return to sports participation after ACL reconstruction. The effect of plyometric exercise intensity on articular cartilage requires further evaluation.

REGISTRATION NUMBER

Clinicaltrials.gov NCT01851655.

Is blood neutrophil-lymphocyte ratio an independent predictor of knee osteoarthritis severity?

Knee osteoarthritis (OA) is one of the most common forms of joint disease, affecting an increasing number of people worldwide. Latest data suggests that inflammation plays a critical role in the pathogenesis of OA. There are a number of inflammatory markers like cytokins and cartilage degradation products that can be used as indicators in OA. Blood neutrophil-lymphocyte ratio (NLR) is a simple non-invasive and cost-effective marker of inflammation in various systemic diseases, but it has not been investigated in OA yet. The aim of the present study was to compare blood NLR levels in patients with severe - Kellgren and Lawrence (KL) grade 4 - knee OA and mild to moderate - KL grades 1-3 - knee OA. A total of 176 patients with knee OA were included in this cross-sectional study. KL grading was done according to the two-view (antero-posterior and lateral) plain radiography of both knees. Demographic characteristics, blood neutrophil, lymphocyte and platelet counts, erythrocyte sedimentation rate, and C-reactive protein were recorded. Blood NLR levels were calculated. In the severe knee OA group, blood NLR levels were found to be elevated as compared to the mild to moderate knee OA group. A blood NLR of ≥2.1 was taken as the cutoff based upon the receiver operating characteristics (roc). In the roc curve analysis, blood NLR ≥ 2.1 had 50 % sensitivity and 77 % specificity in predicting severe knee OA. In multivariate analysis, age and blood NLR ≥ 2.1 emerged as independent predictors of severe knee OA. The results of the present study, for the first time in the literature, suggests blood NLR as a novel and promising inflammatory marker indicating the severity of knee OA.

Bone marrow lesions, subchondral bone cysts and subchondral bone attrition are associated with histological synovitis in patients with end-stage knee osteoarthritis: a cross-sectional study

OBJECTIVE

The aim of this study was to examine the osteoarthritis (OA)-related structural changes associated with histological synovitis in end-stage knee OA patients.

METHODS

Forty end-stage knee OA patients (female: 88%, mean age: 71.8 y) were enrolled. All participants underwent 3.0-T MRI. The structural changes, such as cartilage morphology, subchondral bone marrow lesion (BML), subchondral bone cyst (SBC), subchondral bone attrition (SBA), osteophytes, meniscal lesion and synovitis, were scored using the whole-organ MRI scoring (WORMS) method. Synovial samples were obtained from five regions of interest (ROIs) of the knee joint during total joint replacement surgery. The associations between the histological synovitis score (HSS) and WORMS or the synovial expression levels of cyclooxygenase (COX)-2, interleukin (IL)-1β, IL-6 and transforming growth factor (TGF)-β were examined using Spearman's correlation coefficient.

RESULTS

Among the seven OA-related structural changes, the BML, SBC, SBA and synovitis were significantly associated with the HSS (r = 0.33, 0.35, 0.48 and 0.36, respectively), while other morphological changes were not. Although synovial COX-2, IL-1β or IL-6 expression levels were not associated with the HSS, the synovial TGF-β expression levels were associated with the HSS.

CONCLUSION

The presence of BML, SBC and SBA was associated with histological synovitis in end-stage knee OA patients.

A microfluidic capacitive immunosensor system for human cartilage chitinase-3-like protein 2 (hYKL-39) quantification as an osteoarthritis marker in synovial joint fluid

Flow-based electrochemical osteoarthritis biomarker quantification in joint synovial fluid has been established as first alternative to optical ELISA assays.