Osteoarthritis year in review 2015: clinical

Deficiency of Cbfβ in articular cartilage leads to osteoarthritis-like phenotype through Hippo/Yap, TGFβ, and Wnt/β-catenin signaling pathways

Osteoarthritis (OA) is the most prevalent degenerative joint disorder, causing physical impairments among the elderly. Core binding factor subunit β (Cbfβ) has a critical role in bone homeostasis and cartilage development. However, the function and mechanism of Cbfβ in articular cartilage and OA remains unclear. We found that Cbfβf/fAggrecan-CreERT mice with Cbfβ-deficiency in articular cartilage developed a spontaneous osteoarthritis-like phenotype with articular cartilage degradation. Immunofluorescence staining showed that Cbfβf/fAggrecan-CreERT mice exhibited a significant increase in the expression of articular cartilage degradation markers and inflammatory markers in the knee joints. RNA-sequencing analysis demonstrated that Cbfβ orchestrated Hippo/Yap, TGFβ/Smad, and Wnt/β-catenin signaling pathways in articular cartilage, and Cbfβ deficiency resulted in the abnormal expression of downstream genes involved in maintaining articular cartilage homeostasis. Immunofluorescence staining results showed Cbfβ deficiency significantly increased active β-catenin and TCF4 expression while reducing Yap, TGFβ1, and p-Smad 2/3 expression. Western blot and qPCR validated gene expression changes in hip articular cartilage of Cbfβ-deficient mice. Our results demonstrate that deficiency of Cbfβ in articular cartilage leads to an OA-like phenotype via affecting Hippo/Yap, TGFβ, and Wnt/β-catenin signaling pathways, disrupting articular cartilage homeostasis and leading to the pathological process of OA in mice. Our results indicate that targeting Cbfβ may be a potential therapeutic target for the design of novel and effective treatments for OA.

Cbfβ regulates Wnt/β-catenin, Hippo/Yap, and TGFβ signaling pathways in articular cartilage homeostasis and protects from ACLT surgery-induced osteoarthritis

As the most common degenerative joint disease, osteoarthritis (OA) contributes significantly to pain and disability during aging. Several genes of interest involved in articular cartilage damage in OA have been identified. However, the direct causes of OA are poorly understood. Evaluating the public human RNA-seq dataset showed that Cbfβ, (subunit of a heterodimeric Cbfβ/Runx1,Runx2, or Runx3 complex) expression is decreased in the cartilage of patients with OA. Here, we found that the chondrocyte-specific deletion of Cbfβ in tamoxifen-induced Cbfβf/fCol2α1-CreERT mice caused a spontaneous OA phenotype, worn articular cartilage, increased inflammation, and osteophytes. RNA-sequencing analysis showed that Cbfβ deficiency in articular cartilage resulted in reduced cartilage regeneration, increased canonical Wnt signaling and inflammatory response, and decreased Hippo/YAP signaling and TGF-β signaling. Immunostaining and western blot validated these RNA-seq analysis results. ACLT surgery-induced OA decreased Cbfβ and Yap expression and increased active β-catenin expression in articular cartilage, while local AAV-mediated Cbfβ overexpression promoted Yap expression and diminished active β-catenin expression in OA lesions. Remarkably, AAV-mediated Cbfβ overexpression in knee joints of mice with OA showed the significant protective effect of Cbfβ on articular cartilage in the ACLT OA mouse model. Overall, this study, using loss-of-function and gain-of-function approaches, uncovered that low expression of Cbfβ may be the cause of OA. Moreover, Local admission of Cbfβ may rescue and protect OA through decreasing Wnt/β-catenin signaling, and increasing Hippo/Yap signaling and TGFβ/Smad2/3 signaling in OA articular cartilage, indicating that local Cbfβ overexpression could be an effective strategy for treatment of OA.

Current and Novel Therapeutics for Articular Cartilage Repair and Regeneration

Articular cartilage repair is a sophisticated process that has is being recently investigated. There are several different approaches that are currently reported to promote cartilage repair, like cell-based therapies, biologics, and physical therapy. Cell-based therapies involve the using stem cells or chondrocytes, which make up cartilage, to promote the growth of new cartilage. Biologics, like growth factors, are also being applied to enhance cartilage repair. Physical therapy, like exercise and weight-bearing activities, can also be used to promote cartilage repair by inducing new cartilage growth and improving joint function. Additionally, surgical options like osteochondral autograft, autologous chondrocyte implantation, microfracture, and others are also reported for cartilage regeneration. In the current literature review, we aim to provide an up-to-date discussion about these approaches and discuss the current research status.

Metformin attenuates symptoms of osteoarthritis: role of genetic diversity of Bcl2 and CXCL16 in OA

OBJECTIVE

This study aimed to evaluate the effectiveness of metformin versus placebo in overweight patients with knee osteoarthritis (OA). In addition, to assess the effects of inflammatory mediators and apoptotic proteins in the pathogenesis of OA, the genetic polymorphisms of two genes, one related to apoptosis (rs2279115 of Bcl-2) and the other related to inflammation (rs2277680 of CXCL-16), were investigated.

METHODS

In this double-blind placebo-controlled clinical trial, patients were randomly divided to two groups, one group receiving metformin (n = 44) and the other one receiving an identical inert placebo (n = 44) for 4 consecutive months (starting dose 0.5 g/day for the first week, increase to 1 g/day for the second week, and further increase to 1.5 g/day for the remaining period). Another group of healthy individuals (n = 92) with no history and diagnosis of OA were included in this study in order to evaluate the role of genetics in OA. The outcome of treatment regimen was evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. The frequency of variants of rs2277680 (A181V) and rs2279115 (938C>A) were determined in extracted DNAs using PCR-RFLP method.

RESULTS

Our results indicated an increase in scores of pain (P ≤ 0.0001), activity of daily living (ADL) (P ≤ 0.0001), sport and recreation (Sport/Rec) (P ≤ 0.0001), and quality of life (QOL) (P = 0.003) and total scores of the KOOS questionnaire in the metformin group compared to the placebo group. Susceptibility to OA was associated with age, gender, family history, CC genotype of 938C>A (Pa = 0.001; OR = 5.2; 95% CI = 2.0-13.7), and GG+GA genotypes of A181V (Pa = 0.04; OR = 2.1; 95% CI = 1.1-10.5). The C allele of 938C>A (Pa = 0.04; OR = 2.2; 95% CI = 1.1-9.8) and G allele of A181V (Pa = 0.02; OR = 2.2; 95% CI = 1.1-4.8) were also associated with OA.

CONCLUSION

Our findings support the possible beneficial effects of metformin on improving pain, ADL, Sport/Rec, and QOL in OA patients. Our findings support the association between the CC genotype of Bcl-2 and GG+GA genotypes of CXCL-16 and OA.

The Association Between Severity of Radiographic Knee OA and Recurrent Falls in Middle and Older Aged Adults: The Osteoarthritis Initiative

BACKGROUND

Knee osteoarthritis (KOA) is the most prevalent type of OA and a leading cause of disability in the United States. Falls are a major public health concern in older adults. Our aim was to examine how the severity of radiographic KOA affects recurrent falls in a cohort of middle-aged and older individuals enrolled in the Osteoarthritis Initiative.

METHODS

About 3 972 participants, mean age of 63 years, 58% female were included. Participants were divided into 5 mutually exclusive groups based on their worst Kellgren-Lawrence grade of radiographic KOA from annual x-rays from baseline to 36 months. Generalized estimating equations for repeated logistic regression were used to model the association between KOA severity and the likelihood of recurrent falls (≥2 falls/year) over 5 years of follow-up (>36 to 96 months).

RESULTS

Older adults (≥age 65) with KOA were at higher odds of recurrent falls in comparison to individuals without KOA in multivariate models (possible OA odds ratio [OR] = 2.22, 95% CI = 1.09-4.52; mild OA OR = 2.48, 95% CI = 1.34-4.62; unilateral moderate-severe OA OR = 2.84, 95% CI = 1.47-5.50; bilateral moderate-severe OA OR = 2.52, 95% CI = 1.13-5.62). Middle-aged adults (aged 45-64) with KOA did not have increased odds of recurrent falls in comparison to those without KOA except for possible KOA (OR = 1.86, 95% CI = 1.01-2.78; KOA severity × Age interaction = 0.025).

CONCLUSION

Older adults with radiographic evidence of KOA have an increased likelihood of experiencing recurrent falls in comparison to those without KOA independent of established risk factors. Our results suggest that fall prevention efforts should include older adults with all stages of KOA.

Antiblood Cell Adhesion of Mussel-Inspired Chondroitin Sulfate- and Caffeic Acid-Modified Polycarbonate Membranes

We fabricated a mussel-inspired hemocompatible polycarbonate membrane (PC) modified by the cross-linking of chondroitin sulfate and caffeic acid polymer using CA-CS via a Schiff base and Michael addition reaction and named it CA-CS-PC. The as-fabricated CA-CS-PC membrane shows excellent hydrophilicity with a water contact angle of 0° and a negative surface charge with a zeta potential of -32 mV. The antiadhesion property of the CA-CS-modified PC membrane was investigated by enzyme-linked immunosorbent assay (ELISA), using human plasma protein fibrinogen adsorption studies, and proved to have excellent antiadhesion properties, because of the lower fibrinogen adsorption. In addition, the CA-CS-PC membrane also shows enhanced hemocompatibility. Finally, blood cell attachment tests of the CA-CS-PC membrane were observed by CLSM and SEM, and the obtained results proved that CA-CS-PC effectively resisted cell adhesion, such as platelets and leucocytes. Therefore, this work disclosed a new way to design a simple and versatile modification of the membrane surface by caffeic acid and chondroitin sulfate and apply it for cell adhesion.

Chondroitin sulfate-based composites: a tour d'horizon of their biomedical applications

Chondroitin sulfate (CS), a natural anionic mucopolysaccharide, belonging to the glycosaminoglycan family, acts as the primary element of the extracellular matrix (ECM) of diverse organisms. It comprises repeating units of disaccharides possessing β-1,3-linked N-acetyl galactosamine (GalNAc), and β-1,4-linked D-glucuronic acid (GlcA), and exhibits antitumor, anti-inflammatory, anti-coagulant, anti-oxidant, and anti-thrombogenic activities. It is a naturally acquired bio-macromolecule with beneficial properties, such as biocompatibility, biodegradability, and immensely low toxicity, making it the center of attention in developing biomaterials for various biomedical applications. The authors have discussed the structure, unique properties, and extraction source of CS in the initial section of this review. Further, the current investigations on applications of CS-based composites in various biomedical fields, focusing on delivering active pharmaceutical compounds, tissue engineering, and wound healing, are discussed critically. In addition, the manuscript throws light on preclinical and clinical studies associated with CS composites. A short section on Chondroitinase ABC has also been canvassed. Finally, this review emphasizes the current challenges and prospects of CS in various biomedical fields.

Screening Clinical Changes for the Diagnosis of Early Knee Osteoarthritis: A Cross-Sectional Observational Study

Background: The main objective was to evaluate differences in the clinical, motor, or functional variables in patients with Early Osteoarthritis (EOA) and individuals at risk of developing osteoarthritis (OA). Methods: A cross-sectional study was performed. All the participants were divided into two groups: EOA patients and healthy subjects (HS) at risk of developing OA. The main outcomes were clinical tests, such as those of knee morphology, instability, or proprioception; motor and functional variables, such as knee strength, range of motion, walking speed, and the sit-to-stand test; pain and disability, assessed through the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and Knee injury and Osteoarthritis Outcome Score (KOOS) scales; and knee alignment and leg length inequality, assessed via X-ray images. Results: A total of 97 participants were included (54 EOA and 43 HS). Patients with EOA showed a greater presence of knee pain (p < 0.01). In addition, more EOA patients showed instability both in the left (p < 0.01) and right legs (p < 0.05). Regarding the knee alignment variable, significant differences were found (p < 0.04), with more patients with EOA diagnosed as possessing a varus alignment. In addition, EOA patients showed lower knee strength, since statistically significant differences were found regarding flexion and extension strength in the left leg (Mean Difference (MD): 12.92; p = 0.03; d = −0.46 and MD:7.81; p = 0.04; d = −0.39). Differences were found for the sit-to-stand test scores, showing lower results for the EOA group (MD: −1.91; p < 0.01; d = 0.54). Conclusions: The results of this research show statistically significant differences between patients with EOA and HS at risk of developing OA with respect to pain, disability, instability, knee strength, and the sit-to-stand test. Our results suggest that the evaluation of clinical, motor, and functional features could contribute to an early management of knee OA.

Runx1 is a key regulator of articular cartilage homeostasis by orchestrating YAP, TGFβ, and Wnt signaling in articular cartilage formation and osteoarthritis

Runt-related transcription factor 1 (Runx1) plays a key role in cartilage formation, but its function in articular cartilage formation is unclear. We generated non-inducible and inducible Runx1-deficient mice (Runx1^f/fCol2α1-Cre and Runx1^f/fCol2α1-CreER mice) and found that chondrocyte-specific Runx1-deficient mice developed a spontaneous osteoarthritis (OA)-like phenotype and showed exacerbated articular cartilage destruction under OA, characterized by articular cartilage degradation and cartilage ossification, with decreased Col2α1 expression and increased Mmp13 and Adamts5 expression. RNA-sequencing analysis of hip articular cartilage from the Runx1^f/fCol2α1-Cre mice compared to that from wild-type mice and subsequent validation analyses demonstrated that Runx1 is a central regulator in multiple signaling pathways, converging signals of the Hippo/Yap, TGFβ/Smad, and Wnt/β-catenin pathways into a complex network to regulate the expression of downstream genes, thereby controlling a series of osteoarthritic pathological processes. RNA-sequencing analysis of mutant knee joints showed that Runx1's role in signaling pathways in articular cartilage is different from that in whole knee joints, indicating that Runx1 regulation is tissue-specific. Histopathologic analysis confirmed that Runx1 deficiency decreased the levels of YAP and p-Smad2/3 and increased the levels of active β-catenin. Overexpression of Runx1 dramatically increased YAP expression in chondrocytes. Adeno-associated virus-mediated Runx1 overexpression in the knee joints of osteoarthritic mice showed the protective effect of Runx1 on articular cartilage damaged in OA. Our results notably showed that Runx1 is a central regulator of articular cartilage homeostasis by orchestrating the YAP, TGFβ, and Wnt signaling pathways in the formation of articular cartilage and OA, and targeting Runx1 and its downstream genes may facilitate the design of novel therapeutic approaches for OA.

Chondrogenic primed extracellular vesicles activate miR-455/SOX11/FOXO axis for cartilage regeneration and osteoarthritis treatment

Osteoarthritis (OA) is the leading cause of disability worldwide. Considerable progress has been made using stem-cell-derived therapy. Increasing evidence has demonstrated that the therapeutic effects of BMSCs in chondrogenesis could be attributed to the secreted small extracellular vesicles (sEVs). Herein, we investigated the feasibility of applying engineered EVs with chondrogenic priming as a biomimetic tool in chondrogenesis. We demonstrated that EVs derived from TGFβ3-preconditioned BMSCs presented enriched specific miRNAs that could be transferred to native BMSCs to promote chondrogenesis. In addition, We found that EVs derived from TGFβ3-preconditioned BMSCs rich in miR-455 promoted OA alleviation and cartilage regeneration by activating the SOX11/FOXO signaling pathway. Moreover, the designed T3-EV hydrogel showed great potential in cartilage defect treatment. Our findings provide new means to apply biosafe engineered EVs from chondrogenic primed-BMSCs for cartilage repair and OA treatment, expanding the understanding of chondrogenesis and OA development modulated by EV-miRNAs in vivo.

Transcriptome Analysis Reveals Novel Genes Associated with Cartilage Degeneration in Posttraumatic Osteoarthritis Progression

OBJECTIVE

The current therapeutic strategy for posttraumatic osteoarthritis (PTOA) focuses on early intervention to attenuate disease progression, preserve joint function, and defer joint replacement timing. Sequential transcriptomic changes of articular cartilage in a rat model were investigated to explore the molecular mechanism in early PTOA progression.

DESIGN

Anterior cruciate ligament transection and medial meniscectomy (ACLT + MMx)-induced PTOA model was applied on male Wistar rats. Articular cartilages were harvested at time 0 (naïve), 2 week, and 4 weeks after surgery. Affymetrix Rat genome 230 2.0 array was utilized to analyze the gene expression changes of articular cartilages.

RESULTS

We identified 849 differentially expressed genes (DEGs) at 2 weeks and 223 DEGs at 4 weeks post-ACLT + MMx surgery compared with time 0 (naïve group). Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed to gain further insights from these DEGs. 22 novel genes and 1 novel KEGG pathway (axon guidance) in cartilage degeneration of osteoarthritis were identified. Axon guidance molecules-Gnai1, Sema4d, Plxnb1, and Srgap2 commonly dysregulated in PTOA progression. Gnai1 gene showed a concordant change in protein expression by immunohistochemistry staining.

CONCLUSIONS

Our study identified 22 novel dysregulated genes and axon guidance pathway associated with articular cartilage degeneration in PTOA progression. These findings provide the potential candidates of biomarkers and therapeutic targets for further investigation.

Targeting Discoidin Domain Receptor 2 for the Development of Disease-Modifying Osteoarthritis Drugs

One of the most pressing issues in osteoarthritis (OA) research is the development of disease-modifying OA drugs (DMOADs), as currently there are no such drugs available. The paucity of suitable DMOADs is mostly due to the lack of approved ideal therapeutic targets necessary for the development of these drugs. However, based on recent discoveries from our laboratory and other independent laboratories, it is indicated that a cell surface receptor tyrosine kinase for collagen type II, discoidin domain receptor 2 (DDR2), may be an ideal therapeutic target for the development of DMOADs. In this article, we review the current status of research in understanding roles of DDR2 in the development of OA.

Artificial osteochondral interface of bioactive fibrous membranes mediating calcified cartilage reconstruction

Calcified cartilage is a mineralized osteochondral interface region between the hyaline cartilage and subchondral bone. There are few reported artificial biomaterials that could offer bioactivities for substantial reconstruction of calcified cartilage. Herein we developed new poly(L-lactide-co-caprolactone) (PLCL)-based trilayered fibrous membranes as a functional interface for calcified cartilage reconstruction and superficial cartilage restoration. The trilayered membranes were prepared by the electrospinning technique, and the fibrous morphology was maintained when the chondroitin sulfate (CS) or bioactive glass (BG) particles were introduced in the upper or bottom layer, respectively. Although 30% BG in the bottom layer led to a significant decrease in tensile resistance, the inorganic ion release was remarkably higher than that in the counterpart with 10% BG. The in vivo studies showed that the fibrous membranes as osteochondral interfaces exhibited different biological performances on superficial cartilage restoration and calcified cartilage reconstruction. All of the implanted host hyaline cartilage enabled a self-healing process and an increase in the BG content in the membranes was desirable for promoting the repair of the calcified cartilage with time. The histological staining confirmed the osteochondral interface in the 30% BG bottom membrane maintained appreciable calcified cartilage repair after 12 weeks. These findings demonstrated that such an integrated artificial osteochondral interface containing appropriate bioactive ions are potentially applicable for osteochondral interface tissue engineering.

Articular cartilage repair & joint preservation: A review of the current status of biological approach

The articular cartilage of the joint is the thin viscoelastic layer of the connective tissue. It has a unique anatomy and physiology, which makes the repair of the articular cartilage damage more difficult and challenging due to its limited healing capacity. Increasing knowledge regarding the importance of articular cartilage for joint preservation has led to increased attention on early identification of cartilage damage as well as degeneration in order to delay osteoarthritis. There are various treatment modalities ranging from preventive management, physical therapy, pharmacological, non-pharmacological and surgical treatments exist in current literature. However most of the studies have limited long term follow up and mainly consists of small case series and case reports. This is an up to date concise review discussing the available management options for articular cartilage damage starting to lifestyle modification to pharmacotherapy, physiotherapy, and osteobiologics till various joint preservation techniques that have been in use currently.

The effects on pain and disability of traditional Chinese non-pharmacological therapy for knee osteoarthritis: A protocol for systematic review and meta-analysis

BACKGROUND

Knee osteoarthritis (KOA) is a common chronic joint disease with serious health economic burden. More and more randomized controlled trials have indicated that traditional Chinese non-pharmacological therapy, including acupuncture, Tai Chi, Tuina, etc can significantly improve pain and physical function of patients with KOA. However, the effects of traditional Chinese non-pharmacological therapy for KOA remain controversial. Most previous systematic reviews did not focus on the effects of traditional Chinese non-pharmacological therapy for KOA as a whole. In Chinese community hospital, however, acupuncture, Tuina, and Tai Chi are usually in the management of KOA as whole-body treatment.

METHODS

The electronic databases (PubMed, Embase, MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, China Knowledge Resource Integrated Database, and Wanfang Data) will be searched. The search will include all documents from their inception to December 2021. Two reviewers independently extracted the data and assessed the risk of bias by the Cochrane Risk of Bias Tool for randomized controlled trials. The meta-analysis will be conducted with a random or fixed effect model to calculate the standardized mean difference and 95% confidence intervals based on different heterogeneity using the Review Manager Version 5.3 software. The heterogeneity will be examined by Higgins I2 statistic. The subgroup analysis will be conducted based on different types of traditional Chinese non-pharmacological therapy and different outcomes. Quality of evidence will be assessed using the Grades of Recommendation, Assessment, Development and Evaluation.

RESULTS

The current systematic review and meta-analysis will be conducted to investigate the effects of traditional Chinese non-pharmacological therapy in the management of KOA. The main outcomes will include pain and disability. The secondary outcomes will include quality of life and adverse events.

CONCLUSION

To provide evidence for evidence-based medicine and clinical researchers to choose more effective traditional Chinese non-pharmacological therapy for KOA.

INPLASY REGISTRATION NUMBER

INPLASY202170098.

Circ_0020093 ameliorates IL-1β-induced apoptosis and extracellular matrix degradation of human chondrocytes by upregulating SPRY1 via targeting miR-23b

Osteoarthritis (OA) is a chronic disease characterized by articular cartilage degeneration and uncontrolled chondrocyte apoptosis. At present, accumulating evidence introduces that circular RNA (circRNA) is involved in the development of OA. The aim of our study was to explore the role and the functional mechanism of circ_0020093 in OA cell model. Human chondrocytes were treated with interleukin-1 beta (IL-1β) to construct OA model. The expression of circ_0020093, miR-23b, and Sprouty 1 (SPRY1) mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell apoptosis was assessed by flow cytometry assay. The expression of extracellular matrix (ECM)-associated markers and SPRY1 protein level was detected by qRT-PCR and Western blot. Bioinformatics analysis-predicted relationship between miR-23b and circ_0020093 or SPRY1 was further verified by dual-luciferase reporter assay and RNA pull-down assay. In this study, we found that the expression of circ_0020093 and SPRY1 was declined, while miR-23b expression was elevated in IL-1β-treated chondrocytes. IL-1β induced chondrocyte apoptosis and ECM degradation, while these negative effects were alleviated by circ_0020093 overexpression or miR-23b inhibition. MiR-23b was a target of circ_0020093, and SPRY1 was a downstream target of miR-23b. Rescue experiments showed that miR-23b enrichment reversed the role of circ_0020093 overexpression, and SPRY1 knockdown also reversed the effects of miR-23b inhibition. Importantly, circ_0020093 positively regulated SPRY1 expression by targeting miR-23b. In conclusion, circ_0020093 ameliorates IL-1β-induced apoptosis and ECM degradation of human chondrocytes by regulating the miR-23b/SPRY1 axis.

Expression profiles of long non-coding RNAs in the cartilage of patients with knee osteoarthritis and normal individuals

Knee osteoarthritis is caused by a multifactorial imbalance in the synthesis and degradation of knee chondrocytes, subchondral bone and extracellular matrix. Abnormal expression of long non-coding RNAs (lncRNAs) affects the metabolism, synovitis, autophagy and apoptosis of chondrocytes, as well as the production of cartilage matrix. The aim of the present study was to identify novel targets for the treatment of osteoarthritis and to examine the pathogenesis of the disease. The lncRNA expression profiles of seven patients with knee osteoarthritis and six healthy controls were examined by RNA-sequencing. Differentially expressed lncRNAs were selected for bioinformatics analyses, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Reverse transcription-quantitative PCR (RT-qPCR) was used to further investigate the differential expression of the lncRNAs. A total of 23,583 lncRNAs were identified in osteoarthritis cartilage, including 5,255 upregulated and 5,690 downregulated lncRNAs, compared with normal cartilage. Although there were more downregulated lncRNAs compared with upregulated lncRNAs, among the changed lncRNAs (fold-change >6), there were more upregulated lncRNAs compared with downregulated lncRNAs. Several lncRNAs exhibiting differences were identified as potential therapeutic targets in knee osteoarthritis. GO and KEGG pathway analyses were performed for the target genes of the differentially expressed lncRNAs. RT-qPCR validation was performed on three randomly selected upregulated and downregulated lncRNAs. The results of RT-qPCR were consistent with the findings obtained by RNA-sequencing analysis. The findings from the present study may contribute to the diagnosis of osteoarthritis and may predict the development of osteoarthritis. Furthermore, the differentially expressed lncRNAs may aid in the identification of novel candidate targets for the treatment of knee osteoarthritis.

Different Prevention and Treatment Strategies for Knee Osteoarthritis (KOA) with Various Lower Limb Exoskeletons – A Comprehensive Review

It was reported that about 10% of people suffer from painful knee arthritis, and a quarter of them were severely disabled. The core activities of daily living were severely limited by knee osteoarthritis (KOA). In order to reduce knee pain and prolong the life of the knee joint, there has been an increasing demand on the development of exoskeletons, for prevention and treatment. The course of KOA was closely related to the biomechanics of knee joint, and the pathogenesis was summarized based on the biomechanics of knee joint. For the prevention and clinical treatment, exoskeletons are classified into three categories: prevention, treatment, and rehabilitation after the operation. Furthermore, the design concepts, actuators, sensors, control strategies, and evaluation criteria were presented. Finally, the shortcomings and limitations were summarized. It is useful for researchers to develop suitable exoskeletons in the future.

Strontium regulates stem cell fate during osteogenic differentiation through asymmetric cell division

Strontium, a popular osteogenic component, has been incorporated into various types of orthopaedic biomaterials to enhance bone regeneration. Strontium performs dual effects in promoting bone formation and inhibiting bone resorption. Previous studies have focused on the effects of strontium ions (Sr²⁺) in regulating stem cell behavior to initiate regenerative capacity. However, its mechanisms for regulating the fate and homeostasis of stem cells have not been fully elucidated. In this study, the promotive effect of Sr²⁺ on the osteogenic differentiation of mesenchymal stem cells was confirmed both in vitro and in vivo. Interestingly, in response to Sr²⁺ treatment, stem cells performed asymmetric cell division to balance stemness maintenance and osteogenic differentiation. In initiating osteogenic differentiation, Sr²⁺ maintained more cells in the cell cycle by upregulating the population of S and G2/M phase cells, and this increase in the cell population contributed to enhanced osteogenic differentiation. The divided cells with different cell fates were observed, with one daughter cell maintained stemness, while the other committed to osteogenic lineage. Further investigation revealed that Sr²⁺ activated noncanonical Wnt signaling to regulate the expression and distribution of the Par complex, thus regulating cell division. As a result, the daughter cells committed to different cell fates due to the discriminately activation of osteogenic transcription factors caused by asymmetrically distributed Par3 and aPKC. The results of this study could facilitate the design of biomaterials for bone regeneration by providing a better understanding of cell fate determination regulated by strontium.

Foot orthoses for first metatarsophalangeal joint osteoarthritis: study protocol for the FORT randomised controlled trial

Background

First metatarsophalangeal (MTP) joint osteoarthritis (OA) is a painful and debilitating condition affecting nearly one in 10 people aged over 50 years. Non-drug, non-surgical treatments are recommended by OA clinical guidelines, yet there have only ever been two randomised controlled trials (RCTs) evaluating such strategies in people with first MTP joint OA. Foot orthoses are a common non-drug, non-surgical strategy used by allied health professionals for people with first MTP joint OA, however, it is unknown whether these devices are effective in improving the symptoms associated with the condition. This clinical trial aimed to determine whether contoured foot orthoses lead to greater reductions in first MTP joint pain on walking compared to sham flat insoles in people with first MTP joint OA.

Methods

The FORT trial (Foot ORthoses for big Toe joint osteoarthritis) is a two-arm participant- and assessor-blinded, multi-site RCT conducted in Melbourne, Sydney, Brisbane and the Gold Coast, Australia. We are recruiting 88 community-dwelling people with symptomatic radiographic first MTP joint OA. Following baseline assessment, participants are randomized to receive either: i) contoured foot orthoses; or ii) sham flat insoles following baseline assessment. Participants have two visits with a study podiatrist where they are provided with their allocated insoles, to be worn daily for 12 weeks at all times when wearing shoes. The primary outcome is self-reported first MTP joint pain on walking (numerical rating scale), assessed at baseline and 12 weeks. Secondary outcomes include additional measures of first MTP joint and foot pain, physical function, quality of life, participant-perceived global ratings of change (pain and function), and level of physical activity.

Discussion

This study will provide novel evidence about whether contoured foot orthoses improve pain and other symptoms compared to sham insoles in people with first MTP joint OA. Outcomes will help to inform clinical guidelines and practice about the use of foot orthoses for managing symptoms in this under-researched group of people with OA.

Trial registration

Prospectively registered with the Australian New Zealand Clinical Trials Registry (reference: ACTRN12619000926134) on 3/07/2019.

Diagnostic values of NLR and miR-141 in patients with osteoarthritis and their association with severity of knee osteoarthritis

The present study aimed to explore the diagnostic values of neutrophil-lymphocyte ratio (NLR) and microRNA (miR)-141 in patients with osteoarthritis and their association with the severity of knee osteoarthritis. In total 142 patients with osteoarthritis (the study group) admitted to Shanghai TCM-Integrated Hospital, Shanghai University of TCM from January 2017 to January 2019 and 150 healthy controls (the control group) were enrolled in the present study. NLR and miR-141 in peripheral blood and their diagnostic values for osteoarthritis were compared between the two groups. The two indicators in the study group were significantly increased (P<0.001), and their combined detection had a better diagnostic value for the disease (P<0.001). Moreover, they were closely associated to the progression of the disease and were independent risk factors (P<0.001). To sum up, NLR and miR-141 were significantly increased in the peripheral blood of patients with osteoarthritis. Their combined detection exhibited a good diagnostic value for the disease and may become a potential therapeutic target osteoarthritis in the future.

Molecular docking and molecular dynamics to identify collagenase inhibitors as lead compounds to address osteoarthritis

Osteoarthritis (OA) is a degenerative disease which affects a large number of individuals. Collagenases, which belong to a class of metalloproteases (MMPs), are responsible for the degradation of cartilage manifested in OA. Inhibition of the catalytic domains of these MMPs is one of the important therapeutic strategies proposed for the prevention of OA. The main objective of this work is to evaluate the binding of curcumin and its metabolites with the active sites of collagenases in comparison to standard inhibitors on the basis of our hypothesis that curcumin/metabolites could exhibit an inhibitory effect on MMPs. Here, we report the molecular docking analysis of curcumin and its metabolites with collagenases (MMP-1, MMP-8, MMP-13). Among the molecules tested, curcumin monoglucuronide (CMG) demonstrated the best binding affinity with MMP-13, which is specifically implicated in OA. The CMG-MMP-complexes were further subjected to molecular dynamic simulations to explore the stability of the complexes and to estimate the free binding energies. The results indicated that CMG preferentially bind to MMP-13 in comparison to that of MMP-1 and MMP-8 with binding free energies (ΔG_bind) of (-60.55), (-27.02) and (-46.91) kcal/mol, respectively. This is the first study which suggests that curcumin monoglucuronide can be considered as an effective lead compound to prevent the progression of OA.Communicated by Ramaswamy H. Sarma.

Incidence and risk factors of symptomatic knee osteoarthritis among the Chinese population: analysis from a nationwide longitudinal study

Background

Knee osteoarthritis (OA) is a common disease condition associated with aging and a frequent cause of primary care consultations. Few longitudinal studies have been conducted to investigate the incidence of symptomatic knee osteoarthritis (OA) and to identify its risk factors among the Chinese population.

Methods

The China Health and Retirement Longitudinal Study (CHARLS) is a nationwide longitudinal survey of persons aged ≥45 years. Symptomatic knee OA was diagnosed when both self-reported knee pain and self-reported physician-diagnosis arthritis existed. Using the national survey data collected from the CHARLS, we estimated the incidence of symptomatic knee OA, taking into account the complex survey design and response rate. We applied weighted logistic regression analysis to identify its risk factors.

Results

In the 4-year follow-up, the cumulative incidence of symptomatic knee OA among middle-aged and older Chinese adults was 8.5%; the incidence was higher among females (11.2%) than males (5.6%). Female (odds ratio (OR) 1.98 [95% confidence interval (CI) 1.65–2.37]), rural area (OR 1.32 [95% CI 1.08–1.60]), and West region (OR 2.33 [95% CI 1.89–2.87]) were associated with a higher risk of incident symptomatic knee OA. Physical activities (OR 0.47 [95% CI 0.29–0.76]) and high education level (OR 0.60 [95% CI 0.41–0.88]) was associated with a lower risk of incident symptomatic knee OA, while histories of heart disease (OR 1.40 [95% CI 1.07–1.82]), kidney disease (OR 1.80 [95% CI 1.35–2.39]), and digestive disease (OR 1.54 [95% CI 1.30–1.82]) were associated with a higher risk of incident symptomatic knee OA.

Conclusion

The cumulative incidence of symptomatic knee OA over 4 years was relatively high, and varied by province and region. Lack of physical activities was confirmed to be risk factors of incident symptomatic knee OA. The presence of heart disease, kidney disease, and digestive disease may be associated with a higher risk of incident symptomatic knee OA, further research need to confirm these findings.

A Clinical Approach for the Use of VIP Axis in Inflammatory and Autoimmune Diseases

The neuroendocrine and immune systems are coordinated to maintain the homeostasis of the organism, generating bidirectional communication through shared mediators and receptors. Vasoactive intestinal peptide (VIP) is the paradigm of an endogenous neuropeptide produced by neurons and endocrine and immune cells, involved in the control of both innate and adaptive immune responses. Exogenous administration of VIP exerts therapeutic effects in models of autoimmune/inflammatory diseases mediated by G-protein-coupled receptors (VPAC1 and VPAC2). Currently, there are no curative therapies for inflammatory and autoimmune diseases, and patients present complex diagnostic, therapeutic, and prognostic problems in daily clinical practice due to their heterogeneous nature. This review focuses on the biology of VIP and VIP receptor signaling, as well as its protective effects as an immunomodulatory factor. Recent progress in improving the stability, selectivity, and effectiveness of VIP/receptors analogues and new routes of administration are highlighted, as well as important advances in their use as biomarkers, contributing to their potential application in precision medicine. On the 50th anniversary of VIP's discovery, this review presents a spectrum of potential clinical benefits applied to inflammatory and autoimmune diseases.

The Adipokine Network in Rheumatic Joint Diseases

Rheumatic diseases encompass a diverse group of chronic disorders that commonly affect musculoskeletal structures. Osteoarthritis (OA) and rheumatoid arthritis (RA) are the two most common, leading to considerable functional limitations and irreversible disability when patients are unsuccessfully treated. Although the specific causes of many rheumatic conditions remain unknown, it is generally accepted that immune mechanisms and/or uncontrolled inflammatory responses are involved in their etiology and symptomatology. In this regard, the bidirectional communication between neuroendocrine and immune system has been demonstrated to provide a homeostatic network that is involved in several pathological conditions. Adipokines represent a wide variety of bioactive, immune and inflammatory mediators mainly released by adipocytes that act as signal molecules in the neuroendocrine-immune interactions. Adipokines can also be synthesized by synoviocytes, osteoclasts, osteoblasts, chondrocytes and inflammatory cells in the joint microenvironment, showing potent modulatory properties on different effector cells in OA and RA pathogenesis. Effects of adiponectin, leptin, resistin and visfatin on local and systemic inflammation are broadly described. However, more recently, other adipokines, such as progranulin, chemerin, lipocalin-2, vaspin, omentin-1 and nesfatin, have been recognized to display immunomodulatory actions in rheumatic diseases. This review highlights the latest relevant findings on the role of the adipokine network in the pathophysiology of OA and RA.

Role of SREBP2 gene polymorphism on knee osteoarthritis in the South Indian Hyderabad Population: A hospital based study with G595C variant

Introduction

Osteoarthritis (OA) is a multifactorial disease with genetic factors playing a crucial role, and it has been associated with a family history of obesity. G595C polymorphism in the sterol regulatory element-binding protein 2 (SREBP2) gene has demonstrated an association with knee osteoarthritis (KOA) patients. However, this polymorphism has been never explored in an Indian population. Hence, the current study aimed to examine whether G595C (rs2228314) polymorphism in SREBP2 gene was associated with KOA susceptibility in the South Indian Hyderabad population.

Methods

G595C polymorphism was genotyped with 200 KOA cases and 200 healthy controls using polymerase chain reaction-restriction fragment length polymorphism analysis.

Results

A significant association was observed between age, body mass index (BMI), and family histories in KOA cases and controls (p < 0.05). The current allele (C vs G; OR-2.8 [95%CI = 2.1-3.7]; p < 0.0001) and genotype analysis confirms the significant association with (GC + CC vs GG; OR-3.5 [95%CI = 2.3-5.3]; p < 0.0001 & GC vs GG + CC; OR-1.7 [95%CI = 1.0-2.9]; p = 0.02) KOA vs. control subjects. On stratification analysis, genotype CC and C allele were associated with KOA. Gender association failed to demonstrate positive genotype frequencies (p > 0.05). Multifactor-dimensionality reduction (MDR) analysis showed a positive association with BMI and G595C genotypes (p < 0.05); 51% of the homozygous variant CC genotypes were present in obesity subjects.

Conclusion

In conclusion, our findings suggest that G595C polymorphism in SREBP2 gene is associated with KOA in the South Indian Hyderabad population and presents scope for further investigation of the gene's function in KOA.

High-Temperature Requirement A1 Protease as a Rate-Limiting Factor in the Development of Osteoarthritis

Preserving the mature articular cartilage of joints is a critical focus in the prevention and treatment of osteoarthritis. We determined whether the genetic inactivation of high-temperature requirement A1 (HtrA1) can significantly attenuate the degradation of articular or condylar cartilage. Two types of mouse models of osteoarthritis were used, a spontaneous mutant mouse model [type XI collagen-haploinsufficient (Col11a1^+/-) mice] and two post-traumatic mouse models [destabilization of the medial meniscus (DMM) on the knee and a partial discectomy (PDE) on the temporomandibular joint]. Three different groups of mice were generated: i) HtrA1 was genetically deleted from Col11a1^+/- mice (HtrA1^-/-;Col11a1^+/-), ii) HtrA1-deficient mice (HtrA1^-/-) were subjected to DMM, and iii) HtrA1^-/- mice were subjected to PDE. Knee and temporomandibular joints from the mice were characterized for evidence of cartilage degeneration. The degradation of articular or condylar cartilage was significantly delayed in HtrA1^-/-;Col11a1^+/- mice and HtrA1^-/- mice after DMM or PDE. The amount of collagen type VI was significantly higher in the articular cartilage in HtrA1^-/-;Col11a1^+/- mice, compared with that in Col11a1^+/- mice. The genetic removal of HtrA1 may delay the degradation of articular or condylar cartilage in mice.

Knee osteoarthritis induces atrophy and neuromuscular junction remodeling in the quadriceps and tibialis anterior muscles of rats

Knee osteoarthritis (KOA) is associated with muscle weakness, but it is unclear which structures are involved in the muscle changes. This study assessed morphological alterations and the expression of genes and proteins linked to muscular atrophy and neuromuscular junctions (NMJs) in KOA, induced by anterior cruciate ligament transection (ACLT) in rats. Two groups of rats were assessed: control (without intervention) and KOA (ACLT surgery in the right knee). After 8 weeks, quadriceps, tibialis anterior (TA) and gastrocnemius muscles were analyzed (area of muscle fibers, NMJ, gene and protein expression). KOA group showed atrophy in quadriceps (15.7%) and TA (33%), with an increase in atrogin-1 and muscle RING-finger protein-1 (MuRF-1). KOA group showed quadriceps NMJ remodeling (reduction area and perimeter) and decrease in NMJ diameter in TA muscle. The expression of nicotinic acetylcholine receptor (nAChR) γ-nAChR increased and that of α-nAChR and muscle specific tyrosine kinase (MuSK) declined in the quadriceps, with a decrease in ε-nAChR in TA. MuRF-1 protein expression increased in quadriceps and TA, with no changes in neural cell adhesion molecule (NCAM). In conclusion, ACLT-induced KOA promotes NMJ remodeling and atrophy in quadriceps and TA muscles, associated with inflammatory signs and changes in muscle gene and protein expression.

Exercise in the management of knee and hip osteoarthritis

PURPOSE OF REVIEW

This review focuses on studies published during July 2001 to August 2017 of exercise as an intervention in knee and hip osteoarthritis, including its influence on an array of patient outcomes.

RECENT FINDINGS

Studies continue to illustrate the efficacy of exercise in treating and managing osteoarthritis, with current literature more focused on the knee compared with the hip joint. Both traditional (e.g. strength, aerobic, flexibility) and more nontraditional (e.g. yoga, Tai Chi, aquatic) training modes improve patient outcomes related to joint symptoms, mobility, quality of life, psychological health, musculoskeletal properties, body composition, sleep, and fatigue. Exercise that is adequately dosed (e.g. frequency, intensity) and progressive in nature demonstrated the greatest improvements in patient outcomes. Supervised, partially supervised, and nonsupervised interventions can be successful in the treatment of osteoarthritis, but patient preference regarding level of supervision and mode of exercise may be key predictors in exercise adherence and degree of outcome improvement. A topic of increasing interest in osteoarthritis is the supplementary role of behavior training in exercise interventions.

SUMMARY

Osteoarthritis is a complex, multifactorial disease that can be successfully managed and treated through exercise, with minimal risk for negative consequences. However, to have greatest impact, appropriate exercise prescription is needed. Efforts to achieve correct exercise doses and mitigate patient nonadherence are needed to lessen the lifelong burden of osteoarthritis.

Glucocorticoid signaling and osteoarthritis

Glucocorticoids are steroid hormones synthesized and released by the adrenal cortex. Their main function is to maintain cell homeostasis through a variety of signaling pathways, responding to changes in an organism's environment or developmental status. Mimicking the actions of natural glucocorticoids, synthetic glucocorticoids have been recruited to treat many diseases that implicate glucocorticoid receptor signaling such as osteoarthritis. In osteoarthritis, synthetic glucocorticoids aim to alleviate inflammation and pain. The variation of patients' response and the possibility of complications associated with their long-term use have led to a need for a better understanding of glucocorticoid receptor signaling in osteoarthritis. In this review, we performed a literature search in the molecular pathways that link the osteoarthritic joint to the glucocorticoid receptor signaling. We hope that this information will advance research in the field and propose new molecular targets for the development of more optimized therapies for osteoarthritis.

Effectiveness of Cucumis sativus extract versus glucosamine-chondroitin in the management of moderate osteoarthritis: a randomized controlled trial

Purpose

Osteoarthritis (OA) is an age-related disease caused by the wear and tear of the joints. Presently, there is no known cure for OA, but its management involves the use of high doses of pain killers and antiinflammatory agents with different side and dependency effects. Alternative management strategies involve the use of high doses of glucosamine-chondroitin (GC). This study was carried out to evaluate the efficacy of Q-Actin™, an aqueous extract of Cucumis sativus (cucumber; CSE) against GC in the management of moderate knee OA.

Patients and methods

Overall, 122 patients (56 males and 66 females) aged between 40 and 75 years and diagnosed with moderate knee OA were included in this randomized double-blind, parallel-group clinical trial that took place in three different centers. The 180 day intervention involved two groups of 61 participants in each: the GC group, which received orally the generally prescribed dose of 1,350 mg of GC twice daily and the CSE group, which received orally10 mg twice daily of CSE. The Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Visual Analog scale, and Lequesne's Functional Index were used to evaluate pain, stiffness, and physical function of knee OA in participants at baseline (Day 0) and on Days 30, 60, 90, 120, 150, and 180.

Results

In the CSE group, the WOMAC score was decreased by 22.44% and 70.29% on Days 30 and 180, respectively, compared to a 14.80% and 32.81% decrease in the GC group. Similar trends were observed for all the other pain scores. No adverse effect was reported during the trial period.

Conclusion

The use of 10 mg CSE, twice daily, was effective in reducing pain related to moderate knee OA and can be potentially used in the management of knee pain, stiffness, and physical functions related to OA.

Gait Mechanics After ACL Reconstruction Differ According to Medial Meniscal Treatment

BACKGROUND

Knee osteoarthritis risk is high after anterior cruciate ligament reconstruction (ACLR) and arthroscopic meniscal surgery, and higher among individuals who undergo both. Although osteoarthritis development is multifactorial, altered walking mechanics may influence osteoarthritis progression. The purpose of this study was to compare gait mechanics after ACLR among participants who had undergone no medial meniscal surgery, partial medial meniscectomy, or medial meniscal repair.

METHODS

This was a secondary analysis of data collected prospectively as part of a clinical trial. Sixty-one athletes (mean age of 21.4 ± 8.2 years) who had undergone primary ACLR participated in the study when they achieved impairment resolution (5.3 ± 1.7 months postoperatively), including minimal to no effusion, full knee range of motion, and ≥80% quadriceps-strength symmetry. Participants were classified by concomitant medial meniscal treatment: no involvement or nonsurgical management of a small, stable tear; partial meniscectomy; or meniscal repair. Participants underwent comprehensive walking analyses. Joint contact forces were estimated using a previously validated, electromyography-driven musculoskeletal model. Variables were analyzed using a mixed-model analysis of variance with group and limb comparisons (α = 0.05); group comparisons of interlimb differences in measurements (surgical minus contralateral limb) were performed to determine significant interactions.

RESULTS

The participants in the partial meniscectomy group walked with a higher peak knee adduction moment (pKAM) in the surgical versus the contralateral limb as compared with those in the meniscal repair group and those with no medial meniscal surgery (group difference for partial versus repair: 0.10 N-m/kg-m, p = 0.020; and for partial versus none: 0.06 N-m/kg-m, p = 0.037). Participants in the repair group walked with a smaller percentage of medial to total tibiofemoral loading in the surgical limb compared with both of the other groups (group difference for repair versus partial: -12%, p = 0.001; and for repair versus none: -7%, p = 0.011). The participants in the repair group loaded the medial compartment of the surgical versus the contralateral limb 0.5 times body weight less than did the participants in the partial meniscectomy group.

CONCLUSIONS

Participants in the partial meniscectomy group walked with higher pKAM and shifted loading toward the medial compartment of the surgical limb, while participants in the repair group did the opposite, walking with lower pKAM and unloading the surgical limb relative to the contralateral limb. These findings may partially explain the conflicting evidence regarding pKAM after ACLR and the elevated risk for osteoarthritis (whether from overloading or underloading) after ACLR with concomitant medial meniscectomy or repair.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

α-Lipoic Acid Potentiates the Anti-Inflammatory Activity of Avocado/Soybean Unsaponifiables in Chondrocyte Cultures

Objective Pro-inflammatory mediators such as prostaglandin E-2 (PGE₂) play major roles in the pathogenesis of osteoarthritis (OA). Although current pharmacologic treatments reduce inflammation, their prolonged use is associated with deleterious side effects prompting the search for safer and effective alternative strategies. The present study evaluated whether chondrocyte production of PGE₂ can be suppressed by the combination of avocado/soybean unsaponifiables (ASU) and α-lipoic acid (LA). Design Chondrocytes from articular cartilage of equine joints were incubated for 24 hours with: (1) control media, (2) ASU, (3) LA, or (4) ASU + LA combination. Cells were activated with lipopolysaccharide (LPS), interleukin 1β (IL-1β) or hydrogen peroxide (H₂O₂) for 24 hours and supernatants were immunoassayed for PGE₂. Nuclear factor-kappa B (NF-κB) analyses were performed by immunocytochemistry and Western blot following 1 hour of activation with IL-1β. Results LPS, IL-1β, or H₂O₂ significantly increased PGE₂ production. ASU or LA alone suppressed PGE₂ production in LPS and IL-1β activated cells. Only LA alone at 2.5 µg/mL was inhibitory in H₂O₂-activated chondrocytes. ASU + LA inhibited more than either agent alone in all activated cells. ASU + LA also inhibited the IL-1β induced nuclear translocation of NF-κB. Conclusions The present study provides evidence that chondrocyte PGE₂ production can be inhibited by the combination of ASU + LA more effectively than either ASU or LA alone. Inhibition of PGE₂ production is associated with the suppression of NF-κB translocation. The potent inhibitory effect of ASU + LA on PGE₂ production could offer a potential advantage for a combination anti-inflammatory/antioxidant approach in the management of OA.

Detection of miR-22, miR-140 and Bone Morphogenetic Proteins (BMP)-2 Expression Levels in Synovial Fluid of Osteoarthritis Patients Before and After Arthroscopic Debridement

Background

Osteoarthritis (OA) is a degenerative joint disease often present on the surface and edge of the joint and beneath cartilage forming new bone. Arthroscopy had been used for the treatment of knee OA. This study aimed to measure the expression of miR-22, miR-140, and BMP-2 in patients with OA before and after arthroscopy operation.

Material/Methods

The synovial fluid of 80 patients and 60 healthy volunteers were aspirated using a syringe before OA operation and again six months post-operation in patients with OA. The total RNA was extracted and analyzed by quantitative PCR.

Results

The level of miR-22 was elevated in the progression of OA. The expression of miR-140 level in the synovial fluid was significantly reduced in the patients with OA and was negatively correlated with OA severity compared to controls. Expression of miR-22 and miR-120 returned to normal levels post-operatively. BMP-2 expression was reduced in patients with OA, and returned to normal levels post-operatively. Bioinformatics analysis showed that miR-22 and miR-140 closely target with 3′-UTR of BMP-2 in different positions. The correlation between BMP-2 and miR-22 was negative. The correlation between BMP-2 and miR-140 was positive.

Conclusions

The present study identified a change in miR-22, miR-140, and BMP-2 expression in the synovial fluid of patients with OA before and after arthroscopic debridement. Results provide a novel characterization of the pathogenesis and therefore underlying therapeutic target for OA.

Efficacy of lateral- versus medial-approach hip joint capsule denervation as surgical treatments of the hip joint pain; a neuronal tract tracing study in the sheep

OBJECTIVE

To evaluate efficacy of denervation of the of the hip joint capsule (HJC), as a treatment of hip joint pain. Specifically, we tested the hypothesis that HJC denervation will significantly reduce the number of sensory neurons innervating the capsule.

STUDY DESIGN

Denervation of the HJC from a medial or lateral approach was followed by retrograde tracing of sensory neurons innervating the capsule.

ANIMALS

Twenty adult male sheep (30-40 kg of body weight; Polish merino breed) were used in the study.

METHODS

The hip joint was denervated from medial (n = 5) or lateral (n = 5) surgical approaches. Immediately after denervation, the retrograde neural tract tracer Fast Blue (FB) was injected into the HJC. An additional ten animals (n = 5 for medial and n = 5 for lateral approach) received the same treatment without HJC denervation to provide the appropriate controls.

RESULTS

Results of the study revealed that the vast majority of retrogradely labelled sensory neurons innervating the HJC originate from fifth lumbar to second sacral dorsal root ganglia. Both the medial and the lateral denervations significantly reduced the number of sensory neurons innervating the HJC (39.2% and 69.0% reduction respectively).

CONCLUSIONS

These results show that denervation of the HJC is an effective surgical procedure for reduction of the sensory neuronal input to the HJC. Moreover, the lateral approach was found to be significantly more effective for reducing sensory innervation as compared to the medial one.

Mechanical viability of a thermoplastic elastomer hydrogel as a soft tissue replacement material

Hydrogels are a class of synthetic biomaterials composed of a polymer network that swells with water and as such they have both an elastic and viscous component making them ideal for soft tissue applications. This study characterizes the compressive, tensile, and shear properties of a thermoplastic elastomer (TPE) hydrogel and compares the results to published literature values for soft tissues such as articular cartilage, the knee meniscus, and intervertebral disc components. The results show the TPE hydrogel material is viscoelastic, strain rate dependent, has similar surface and bulk properties, displays minimal damping under dynamic load, and has tension-compression asymmetry. When compared to other soft tissues it has a comparable equilibrium compressive modulus of approximately 0.5MPa and shear modulus of 0.2MPa. With a tensile modulus of only 0.2MPa though, the TPE hydrogel is inferior in tension to most collagen based soft tissues. Additional steps may be necessary to reinforce the hydrogel system and increase tensile modulus depending on the desired soft tissue application. It can be concluded that this material could be a viable option for soft tissue replacements.

Traditional Chinese medicine for knee osteoarthritis: An overview of systematic review

BACKGROUND

Traditional Chinese medicine (TCM) has been accepted as a complementary therapy for knee osteoarthritis. However, the efficacy and safety of the intervention were still conflicting and uncertain. Meanwhile, the quality of methodology and evidence in the field was unknown.

OBJECTIVE

To summarize the characteristics and critically evaluate the quality of methodology, as well as the evidence of systematic reviews (SRs) on TCM for knee osteoarthritis.

METHODS

Five electronic databases were searched from inception to April 2016. The methodological quality of the included studies was assessed by AMSTAR and ROBIS. The quality of the evidence was determined using the GRADE approach.

RESULTS

Ten SRs were included. The conclusions suggest that TCM provides potential benefits for patients with knee osteoarthritis. These benefits include pain relief, functional improvement, and presence of few adverse events. Limitations of the methodological quality mainly included the lack of a-priori protocol or protocol registration and incomprehensive literature search. A list of excluded studies was also not provided. The overall quality of evidence in the SRs was poor, ranging from "very low" to "low," mainly because of the serious risk of bias of original trials, inconsistencies, and imprecision in the outcomes.

CONCLUSIONS

TCM generally appears to be effective for knee osteoarthritis treatment. However, the evidence is not robust enough because of the methodological flaws in SRs. Hence, these conclusions on available SRs should be treated with caution for clinical practice.

Suppression of miR-301a alleviates LPS-induced inflammatory injury in ATDC5 chondrogenic cells by targeting Sirt1

Osteoarthritis is one of the most common joint diseases and is characterized by joint inflammation. MicroRNAs (miRNA) play an important role in osteoarthritis. In this study, we examined the role of miR-301a in lipopolysaccharide (LPS)-treated murine chondrogenic ATDC5 cells. LPS at 10 µg/mL concentration was used to induce inflammatory injury in chondrogenic cells. Cell Counting Kit-8 assay was used to measure cell viability and flow cytometry was used to measure cell apoptosis. Effect of miR-301a on concentrations of inflammatory cytokines was measured using ELISA, and on mRNA expressions was measured using qRT-PCR. The miR-301 target was identified by luciferase reporter assay. Western blot analysis was used to measure the expressions of apoptotic proteins, Sirt1, and PI3K/AKT and NF-κB pathways proteins. Treatment with LPS decreased cell viability, and increased apoptosis, inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α) level, and miR-301a expression. Overexpression of miR-301a aggravated the effects of LPS on the chondrogenic cells and the inflammatory cytokines by negatively regulating Sirt1 expression. Sirt1 was identified as a target of miR-301. Suppression of miR-301a showed the opposite effects. Western blot showed that suppression of miR-301a increased the expression of PI3K/AKT and NF-κB pathways proteins. Suppression of miR-301a expression alleviated LPS-induced chondrogenic cell injury by upregulating Sirt1 and activating the PI3K/AKT and NF-κB signal pathways.

Longitudinal study of sodium MRI of articular cartilage in patients with knee osteoarthritis: initial experience with 16-month follow-up

OBJECTIVES

To evaluate the potential of sodium MRI to detect changes over time of apparent sodium concentration (ASC) in articular cartilage in patients with knee osteoarthritis (OA).

METHODS

The cartilage of 12 patients with knee OA were scanned twice over a period of approximately 16 months with two sodium MRI sequences at 7 T: without fluid suppression (radial 3D) and with fluid suppression by adiabatic inversion recovery (IR). Changes between baseline and follow-up of mean and standard deviation of ASC (in mM), and their rate of change (in mM/day), were measured in the patellar, femorotibial medial and lateral cartilage regions for each subject. A matched-pair Wilcoxon signed rank test was used to assess significance of the changes.

RESULTS

Changes in mean and in standard deviation of ASC, and in their respective rate of change over time, were only statistically different when data was acquired with the fluid-suppressed sequence. A significant decrease (p = 0.001) of approximately 70 mM in mean ASC was measured between the two IR scans.

CONCLUSION

Quantitative sodium MRI with fluid suppression by adiabatic IR at 7 T has the potential to detect a decrease of ASC over time in articular cartilage of patients with knee osteoarthritis.

KEY POINTS

• Sodium MRI can detect apparent sodium concentration (ASC) in cartilage • Longitudinal study: sodium MRI can detect changes in ASC over time • Potential for follow-up studies of cartilage degradation in knee osteoarthritis.

Microarray study of gene expression profile to identify new candidate genes involved in the molecular mechanism of leptin-induced knee joint osteoarthritis in rat

BACKGROUND

Osteoarthritis (OA) is one of the most prevalent chronic joint diseases while the precise genetic mechanism remains elusive. In this study, we investigated the gene expression profile in OA by microarray analysis.

RESULTS

Histopathological characteristics of OA cartilage were examined using a rat model of leptin-induced OA. Gene expression profile of leptin-induced articular cartilage and healthy rat cartilage were compared using genome-wide microarray hybridization. A total of 1857 genes differentially expressed genes (1197 upregulated and 660 downregulated) were identified, some of which are known to be associated with leptin-induced OA phenotype. These included genes related to MMPs, inflammatory factors, growth factors, apoptotic genes and osteogenic genes. In addition, upregulated expressions of some new candidate genes, which have hitherto fore not been linked to OA (such as BCL2L11) were detected in leptin-induced OA cartilage, which suggests that these genes might be important for OA molecular mechanism.

CONCLUSION

Our findings suggest that pathogenesis of leptin-induced OA involves modulation of expression of multiple genes, although the underlying molecular mechanisms need to be studied further. Further investigation of leptin-induced gene expression changes is needed to gain new insights into the molecular mechanism of OA pathogenesis.

Mesenchymal Stem Cell-Based Cartilage Regeneration Approach and Cell Senescence: Can We Manipulate Cell Aging and Function?

Aging is the most prominent risk factor triggering several degenerative diseases, such as osteoarthritis (OA). Due to its poor self-healing capacity, once injured cartilage needs to be reestablished. This process might be approached through resorting to cell-based therapies and/or tissue engineering. Human mesenchymal stem cells (MSCs) represent a promising approach due to their chondrogenic differentiation potential. Presently, in vitro chondrogenic differentiation of MSCs is limited by two main reasons as follows: aging of MSCs, which determines the loss of cell proliferative and differentiation capacity and MSC-derived chondrocyte hypertrophic differentiation, which limits the use of these cells in cartilage tissue regeneration approach. The effect of aging on MSCs is fundamental for stem cell-based therapy development, especially in older subjects. In the present review we focus on homeostasis alterations occurring in MSC-derived chondrocytes during in vitro aging. Moreover, we deal with potential cell aging regulation approaches, such as cell stimulation through telomerase activators, mechanical strain, and epigenetic regulation. Future investigations in this field might provide new insights into innovative strategies for cartilage regeneration and potentially inspire novel therapeutic approaches for OA treatment.

Nonoperative Options for Management of Articular Cartilage Disease

Nonoperative options for articular cartilage injury are pervasive but have not shown to be curative. Recommendations for low-impact exercise and weight loss provide benefit and are a foundation for the treatment of osteoarthritis. Judicious use of NSAIDs and acetaminophen can be appropriate for pain management. Topical NSAIDs may be a treatment option with fewer side effects than its oral counterpart. Additionally, viscosupplementation injections are useful for mild to moderate knee osteoarthritis, whereas short-term pain relief is provided by intra-articular corticosteroid injections. Future studies to individualize treatment options based on patient phenotype and genotype may hold promise.

T140 blocks the SDF-1/CXCR4 signaling pathway and prevents cartilage degeneration in an osteoarthritis disease model

Osteoarthritis (OA) is one of the most common diseases affecting older people; however, there remains no effective targeted drug to combat OA. The aims of this study were (1) to explore the effect of T140 in regulating degeneration of articular cartilage in vivo by targeted blocking of the SDF-1/CXCR4 signaling pathway, and (2) to provide experimental evidence for the development of a novel OA-targeted pharmacotherapy. Thirty-six healthy Hartley guinea pigs were randomly divided into three groups: a T140-treated group (n = 12), a phosphate buffer saline control group (n = 12) and an untreated control group (n = 12). At 2, 4, 6, 8, 10 and 12 weeks of treatment, SDF-1 in serum was quantified by enzyme-linked immunosorbent assay. At 12 weeks of treatment, the cartilage from knee tibial plateau in the knee joint was collected for H&E, Safranin-O staining and Mankin grading; measurement for mRNA levels of matrix metalloproteinases (MMP-3, MMP-9 and MMP-13), aggrecan (ACAN) and collagen II (Col II) using RT-PCR; and measurement for Col II protein levels by western blot. Results showed that SDF-1 in serum increased in the T140 group and increased in the control groups. H&E and Safranin-O staining revealed less cartilage loss in T140-treated animals compared to controls. The mRNA levels of MMP-3, MMP-9 and MMP-13 in cartilage were much lower in the T140 group than other groups, but mRNA levels of ACAN and Col II in cartilage were higher in the T140-treated group. Col II protein levels in the T140 group and control groups were different. T140 can downregulate the expression of matrix-degrading enzyme and lessen the degeneration of cartilage by blocking the SDF-1/CRCR4 signaling pathway in vivo. This mechanism may present a pharmacological target for the treatment of OA.