Pro-inflammatory cytokines: The link between obesity and osteoarthritis

Structural characterization of Poria cocos oligosaccharides and their effects on the hepatic metabolome in high-fat diet-fed mice

In this study, novel Poria cocos oligosaccharides (PCO) were prepared by enzymatic degradation, and their polymerization degree was determined to be 2-6 by LC-MS analysis. By monosaccharide composition analysis, methylation assay, FT-IR, and NMR analysis, PCO were deduced to contain the sugar residues of (1 → 2)-β-D-Glcp, (1 → 2)-α-D-Glcp, and (1 → 4)-α-D-Glcp. Using an HFD-fed mouse model with dyslipidemia, PCO could significantly suppress lipid metabolism disorders, characterized by the reduction of lipid accumulation and inflammatory responses in the blood and liver tissues. Based on the non-targeted metabolomic analysis and Spearman's correlation analysis, we presume that the preventive effect of PCO on dyslipidemia might contribute to the reversal of changed metabolic pathways, which were related to the metabolisms of glycerophospholipids, unsaturated fatty acids, amino acids, choline, bile acids, tryptophan, sphingolipids, and glutathione. Our research shed light on the potential application of PCO for the treatment of dyslipidemia.

Deformation of the Titanium Plate Stabilizing the Lateral Ankle Fracture Due to Its Overloading in Case of the Young, Obese Patient: Case Report Including the Biomechanical Analysis

The number of overweight and obese patients in developed countries is gradually increasing. It was reported that 1287 (64%) out of 2007 adults operated on in 2017 had a body mass index (BMI) greater than 25 kg/m2, and 26.4% even greater than 30, while the BMI of the most obese patient was as high as 57.6 kg/m2. Such distressing statistics raised an issue related to the inadequate durability of implants used for the fixation of bone fractures. Implants for the lower-extremity fractures may not be durable enough to fit the requirements of overweight and obese patients. This case report presents the history of a 23-year-old obese male with a BMI of 38.7, who bent the angularly stabile titanium plate stabilizing his broken lateral ankle and torn distal tibiofibular syndesmosis. Biomechanical analysis showed that the maximal static bending moment registered during one-leg standing was equal to 1.55 Nm. This value was circa one-third of the maximally admissible bending moment for this particular plate (5.34 Nm) that could be transmitted without its plastic deformation. Since dynamic forces exceed static ones several (3–12) times during typical activities, such as walking, climbing the stairs, running, and jumping, unpredictable forces may occur and increase the risk of loosening, bending, and even breaking implants. None of these situations should have occurred for the typical patient’s body mass of 75 kg, or even for the analyzed mass of the young patient (120 kg) who tried to avoid excessive loading during his daily routine. Subsequent implant bending and destabilization of the fracture shows that for the significantly high and still growing number of obese patients, a very strict physical regime should be recommended to prevent overabundant dynamic loads. On the other hand, the geometry of implants dedicated to these patients should be reconsidered.

Temporomandibular disorders, bite force and osseous changes of the temporomandibular joints in patients with hypermobile Ehlers-Danlos syndrome compared to a healthy control group

Background

Ehlers‐Danlos syndrome (EDS) is a hereditary disorder that affects the connective tissue and collagen structures in the body characterised by joint hypermobility, skin hyperextensibility and tissue fragility.

Objective

The aim was to investigate temporomandibular disorders (TMD), bite force, teeth in occlusal contact and osseous changes of the temporomandibular joints (TMJs) in 26 patients with hypermobile EDS (hEDS), differentiated by a genetic test, compared to 39 healthy controls.

Methods

Clinical examination according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), radiological examinations of the TMJs by cone‐beam‐computed tomographic (CBCT) scans, registration of bite force and teeth in occlusal contact was performed. Statistical analyses included Fisher's Exact Test, multiple logistic and linear regression models adjusted for age, gender and Body Mass Index (BMI).

Results

Single symptoms and signs of TMD occurred significantly more often in hEDS (p = .002; p = .001; p = .003; p = <.0001; p = .012) and maximum mouth opening was significantly smaller in hEDS compared to controls (p = <.0001). The DC/TMD diagnosis myalgia, myofascial pain with referral, arthralgia, headache attributed to TMD, disc displacement disorders and degenerative joint disease occurred significantly more often in hEDS compared to controls (p = .000; p = .008; p = .003; p = .000; p = <.0001; p = .010, respectively). No significant differences were found in bite force and in teeth in occlusal contact between the groups (p > .05). On CBCT of the TMJs, subcortical sclerosis occurred significantly more often in hEDS compared to controls (p = .005).

Conclusion

Symptoms and signs of TMD and osseous changes of the TMJs occurred significantly more often in hEDS. Bite force and teeth in occlusal contact were comparable to controls.

Pain in Hemophilia: Unexplored Role of Oxidative Stress

Hemophilia is the most common X-linked bleeding diathesis caused by the genetic deficiency of coagulation factors VIII or IX. Despite treatment advances and improvements in clinical management to prevent bleeding, management of acute and chronic pain remains to be established. Repeated bleeding of the joints leads to arthropathy, causing pain in hemophilia. However, mechanisms underlying the pathogenesis of pain in hemophilia remain underexamined. Herein, we describe the novel perspectives on the role for oxidative stress in the periphery and the central nervous system that may contribute to pain in hemophilia. Specifically, we cross examine preclinical and clinical studies that address the contribution of oxidative stress in hemophilia and related diseases that affect synovial tissue to induce acute and potentially chronic pain. This understanding would help provide potential treatable targets using antioxidants to ameliorate pain in hemophilia.

Evaluation of the therapeutic and the chemical effects of balneological treatment on clinical and laboratory parameters in knee osteoarthritis: a randomized, controlled, single-blinded trial

The purpose of this study was to investigate the therapeutic and the chemical effects of balneological treatment (peloidotherapy + hydrotherapy), and its effects on serum levels of interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and insulin-like growth factor-1 (IGF-1) in patients with knee osteoarthritis (OA). Sixty-four (64) knee OA patients were randomly divided into study and control groups. Balneological treatment, consisting of hydrotherapy, and peloidotherapy were given to both groups. Unlike the study group, in the control group, the peloid was applied over a stretch film cover, preventing any contact between the skin and peloid. Clinical outcome measures of the study were pain degree, patient's and investigator's global assessment on visual analog scale (VAS-pain, VAS-PGA, VAS-IGA), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (pain, stiffness, and physical function). Patients were evaluated at baseline, post-treatment (after 10th session), and 3 and 6 months after treatment. Blood samples were taken at baseline, post- treatment, and 6 months after treatment for analysis of IL-1β, TNF-α, and IGF-1 serum levels. When compared with the baseline, VAS measurements decreased significantly in almost all evaluation periods in both groups, and no difference was observed between the groups. In the study group, WOMAC scores showed significant improvement in all assessments. In the control group, pain and physical function subscores of WOMAC significantly decreased at post-treatment and 3 months after treatment. In group comparison, pain and stiffness subscores showed a significant difference in favor of the study group at 6 months after treatment. No clinically significant improvement was seen in levels of IL-1β and IGF-1 in both groups during the whole assessment period. Because of TNF-α kit failure, we could not evaluate the measurements. In conclusion, balneological treatment is an effective treatment option to improve the pain and functional capacity of patients with knee OA. The application of peloid by contact with the skin is superior in the long-term period, which means that in addition to the thermal effect, the chemical content of peloid can also contribute to the therapeutic effect.

LINC01534/miR-135b-5p/PTPRT axis regulates inflammatory response in loosening total hip replacement via modulating NF-κB signaling pathway

Aseptic loosening after total hip replacement brings adverse health outcomes and increased risk for complications. The resorptive activity of inflammatory cells activated by the presence of wear-generated debris plays a critical role in debris-induced osteolysis. Previous studies indicate that the abnormally expressed LINC01534 plays a critical role in inflammatory responses. In this study, we aimed to elucidate the functional role and underlying mechanism of LINC01534 in debris-induced osteolysis. We first confirmed that LINC01534 was highly expressed in hip cartilage tissues from aseptic loosening patients. By using an IL-1β-induced inflammation model mimicking debris-induced osteolysis, we demonstrated that LINC01534 promoted IL-1β-induced inflammatory response in hip chondrocytes. Knockdown of LINC01534 inhibited the expression of inflammatory IL-6, IL-8, and TNF-α in hip chondrocytes. Our results showed that LINC01534 functioned as a competing endogenous RNA (ceRNA) by sponging miR-135b-5p in hip chondrocytes. Moreover, bioinformatics analysis and luciferase reporter assay demonstrated that CCHC-Type Zinc Finger Nucleic Acid Binding Protein (PTPRT) is a downstream target of miR-135b-5p. Knockdown of PTPRT attenuated the IL-1β-induced inflammatory responses in hip chondrocytes. In addition, we revealed that inhibition of miR-135b-5p or overexpression of PTPRT could antagonize the effects of LINC01534 knockdown on inflammation attenuation in hip chondrocytes. Mechanistically, we demonstrated that LINC01534/miR-135b-5p/PTPRT axis regulated the NF-κB signaling pathway in hip chondrocytes. Taken together, our findings suggest that LINC01534/miR-135b-5p/PTPRT axis might be a valuable therapeutic target for the treatment of debris-induced osteolysis.

Platelet-rich plasma inhibits inflammation, apoptosis, and the NLRP3/Caspase-1 pathway and induces matrix metalloproteinases and proliferation of IL-1β-induced articular chondrocytes by downregulating T-box transcription factor 3

Objectives

Osteoarthritis (OA) is a chronic joint disease characterized by osteoproliferation and the degeneration and destruction of articular cartilage. Platelet-rich plasma (PRP) is rich in various growth factors that have been reported to promote bone defect repair. This study examined the specific role and mechanism of PRP in OA.

Methods

OA model cells were created by treating articular chondrocytes with IL-1β. After treatment of the model cells with PRP or/and a T-box transcription factor 3 (TBX3)-overexpression plasmid, TBX3 expression was monitored via RT-qPCR, western blotting, and immunofluorescence assays. IL-1β, IL-33, and Caspase-3 levels were detected with ELISA kits. Levels of NLRP3, Caspase-1, MMP9, MMP13, and COL2A1 expression were evaluated by western blotting, and cell proliferation was assessed by the CCK-8 assay.

Results

Our results showed that TBX3 expression was upregulated in IL-1β-induced articular chondrocytes. IL-1β stimulation induced inflammation and the production of matrix metalloproteinases, activated Caspase-3 and the NLRP3/Caspase-1 pathway, inhibited the proliferation of articular chondrocytes; however, all those affects mediated by IL-1β could be markedly reversed by PRP. We also found that PRP alleviated IL-1β-induced inflammation, apoptosis, and extracellular matrix degradation in articular chondrocytes by inhibiting TBX3. Our findings suggest that PRP alleviates OA progression in vitro by downregulating TBX3.

Conclusion

PRP suppressed OA progression in vitro by inhibiting TBX3, which may be its mechanism of action in treating OA.

Circulating Extracellular Vesicles Are Strongly Associated With Cardiovascular Risk Markers

Background

Extracellular vesicles (EVs) are submicron membrane-bound vesicles released from various cells, which are emerging as a potential novel biomarker in cardiovascular diseases (CVDs) due to their procoagulatory and prothrombotic properties. However, there is little information about the relationships between circulating EVs and conventional and thrombogenic risk markers of CVDs.

Objective

To investigate the relationships between circulating EVs, conventional cardiovascular risk markers and thrombogenic markers in subjects with moderate risk of CVDs.

Design

Subjects (n = 40) aged 40-70 years with moderate risk of CVDs were recruited and assessed for body mass index, blood pressure and plasma lipid profile, as well as platelet aggregation, clot formation, thrombin generation and fibrinolysis. Numbers of circulating EVs were assessed by Nanoparticle Tracking Analysis and flow cytometry. A range of assays were used to assess the procoagulatory activity of plasma and circulating EVs.

Results

Circulating EV numbers were positively associated with body mass index, blood pressure, plasma triacylglycerol concentration and overall CVD risk. Higher circulating EV numbers were also associated with increased thrombin generation and enhanced clot formation, and EVs isolated from subjects with moderate CVD risk promoted thrombin generation ex vivo. Higher numbers of endothelial-derived EVs were associated with a greater tendency for clot lysis. Plasma triacylglycerol concentration and diastolic blood pressure independently predicted circulating EV numbers, and EV numbers independently predicted aspects of thrombin generation and clot formation and 10-year CVD risk.

Conclusion

Circulating EVs were strongly associated with both conventional and thrombogenic risk markers of CVDs, and also with overall CVD risk, highlighting a potentially important role for EVs in CVDs.

New Progress in Basic Research of Macrophages in the Pathogenesis and Treatment of Low Back Pain

Low back pain (LBP) is quite common in clinical practice, which can lead to long-term bed rest or even disability. It is a worldwide health problem remains to be solved. LBP can be induced or exacerbated by abnormal structure and function of spinal tissue such as intervertebral disc (IVD), dorsal root ganglion (DRG) and muscle; IVD degeneration (IVDD) is considered as the most important among all the pathogenic factors. Inflammation, immune response, mechanical load, and hypoxia etc., can induce LBP by affecting the spinal tissue, among which inflammation and immune response are the key link. Inflammation and immune response play a double-edged sword role in LBP. As the main phagocytic cells in the body, macrophages are closely related to body homeostasis and various diseases. Recent studies have shown that macrophages are the only inflammatory cells that can penetrate the closed nucleus pulposus, expressed in various structures of the IVD, and the number is positively correlated with the degree of IVDD. Moreover, macrophages play a phagocytosis role or regulate the metabolism of DRG and muscle tissues through neuro-immune mechanism, while the imbalance of macrophages polarization will lead to more inflammatory factors to chemotaxis and aggregation, forming an "inflammatory waterfall" effect similar to "positive feedback," which greatly aggravates LBP. Regulation of macrophages migration and polarization, inhibition of inflammation and continuous activation of immune response by molecular biological technology can markedly improve the inflammatory microenvironment, and thus effectively prevent and treat LBP. Studies on macrophages and LBP were mainly focused in the last 3-5 years, attracting more and more scholars' attention. This paper summarizes the new research progress of macrophages in the pathogenesis and treatment of LBP, aiming to provide an important clinical prevention and treatment strategy for LBP.

Evaluation of Biomarkers and Immune Microenvironment of Osteoarthritis: Evidence From Omics Data and Machine Learning

Objectives: This study aimed to identify novel biomarkers for osteoarthritis (OA) and explore potential pathological immune cell infiltration. Methods: We identified differentially expressed genes (DEGs) between OA and normal synovial tissues using the limma package in R, and performed enrichment analyses to understand the functions and enriched pathways of DEGs. Weighted gene co-expression network analysis (WGCNA) and distinct machine-learning algorithms were then used to identify hub modules and candidate biomarkers. We assessed the diagnostic value of the candidate biomarkers using receiver operating characteristic (ROC) analysis. We then used the CIBERSORT algorithm to analyze immune cell infiltration patterns, and the Wilcoxon test to screen out hub immune cells that might affect OA occurrence. Finally, the expression levels of hub biomarkers were confirmed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Results: We identified 102 up-regulated genes and 110 down-regulated genes. The functional enrichment analysis results showed that DEGs are enriched mainly in immune response pathways. Combining the results of the algorithms and ROC analysis, we identified GUCA1A and NELL1 as potential diagnostic biomarkers for OA, and validated their diagnosibility using an external dataset. Construction of a TF-mRNA-miRNA network enabled prediction of potential candidate compounds targeting hub biomarkers. Immune cell infiltration analyses revealed the expression of hub biomarkers to be correlated with CD8 T cells, memory B cells, M0/M2 macrophages, resting mast cells and resting dendritic cells. qRT-PCR results showed both GUCA1A and NELL1 were significantly increased in OA samples (p < 0.01). All validations are consistent with the microarray hybridization, indicating that GUCA1A and NELL1 may be involved in the pathogenesis of OA. Conclusion: The findings suggest that GUCA1A and NELL1, closely related to OA occurrence and progression, represent new OA candidate markers, and that immune cell infiltration plays a significant role in the progression of OA.

Bioactive Evaluation of Ursane-Type Pentacyclic Triterpenoids: β-Boswellic Acid Interferes with the Glycosylation and Transport of Intercellular Adhesion Molecule-1 in Human Lung Adenocarcinoma A549 Cells

Ursane-type pentacyclic triterpenoids exert various biological effects, including anticancer and anti-inflammatory activities. We previously reported that ursolic acid, corosolic acid, and asiatic acid interfered with the intracellular trafficking and glycosylation of intercellular adhesion molecule-1 (ICAM-1) in human lung adenocarcinoma A549 cells stimulated with the pro-inflammatory cytokine interleukin-1α. However, the structure–activity relationship of ursane-type pentacyclic triterpenoids remains unclear. In the present study, the biological activities of seven ursane-type pentacyclic triterpenoids (β-boswellic acid, uvaol, madecassic acid, 3-O-acetyl-11-keto-β-boswellic acid, ursolic acid, corosolic acid, and asiatic acid) were investigated. We revealed that the inhibitory activities of ursane-type pentacyclic triterpenoids on the cell surface expression and glycosylation of ICAM-1 and α-glucosidase activity were influenced by the number of hydroxy groups and/or the presence and position of a carboxyl group. We also showed that β-boswellic acid interfered with ICAM-1 glycosylation in a different manner from other ursane-type pentacyclic triterpenoids.

PRDX2 Knockdown Inhibits Extracellular Matrix Synthesis of Chondrocytes by Inhibiting Wnt5a/YAP1/CTGF and Activating IL-6/JAK2/STAT3 Pathways in Deer Antler

Although peroxiredoxin 2 (PRDX2) plays a vital role in relieving oxidative stress, its physiological function in cartilage development remains almost unknown. In this study, we found that the expression of PRDX2 significantly increased in the chondrocytes compared with pre-chondrocytes. PRDX2 knockdown significantly decreased the expression of extracellular matrix (ECM) protein (Col2a and Aggrecan), which led to blocked cartilage formation. Moreover, PRDX2 knockdown also inhibited the expression of connective tissue growth factor (CTGF). CTGF is an important growth factor that regulates synthesis of ECM proteins. We explored the possible regulatory mechanism by which PRDX2 regulated the expression of CTGF. Our results demonstrated that PRDX2 knockdown downregulated the expression of CTGF by inhibiting Wnt5a/Yes-associated protein 1 (YAP1) pathway. In addition, PRDX2 knockdown promoted the expression of interleukin 6 (IL-6), indicating PRDX2 expression had an anti-inflammatory function during antler growth. Mechanistically, PRDX2 knockdown promoted cartilage matrix degradation by activating the IL-6-mediated Janus Kinase 2/Signal Transducer and Activator of Transcription 3 (JAK2/STAT3) signaling pathway. These results reveal that PRDX2 is a potential regulator that promotes cartilage extracellular matrix synthesis.

RNA-seq based integrative analysis of potential crucial genes and pathways associated with patellar instability

Patellar instability (PI) is a common knee injury in adolescents, but the crucial biomarkers and molecular mechanisms associated with it remain unclear. We established a PI mouse model and investigated PI-related changes in gene expression by RNA sequencing (RNA-seq). Differentially expressed gene (DEG) analysis and enrichment analysis were performed to identify crucial genes and pathways associated with PI. Subsequently, a protein-protein interaction, DEG-miRNA, DEG-transcription factors, and DEG-drug interaction networks were constructed to reveal hub genes, molecular mechanism, and potential drugs for PI. Finally, the reliability of the sequencing results was confirmed by real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. Upon comparison with the control group, 69 genes were differently expressed in PI, including 17 upregulated and 52 downregulated ones. The DEGs were significantly enriched in Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway and immune responses. The protein–protein interaction network identified ten PI-related hub genes, all of which are involved in the JAK/STAT signaling pathway or inflammation-related pathways. DEG-miRNA and DEG-transcription factor networks offered new insights for regulating DEGs post-transcriptionally. We also determined potential therapeutic drugs or molecular compounds that could restore dysregulated expression of DEGs via the DGIdb database. RT-qPCR results were consistent with the RNA-seq, confirming the reliability of the sequencing data. Immunohistochemistry results suggested that JAK1 and STAT3 expression was increased in PI. Our study explored the potential molecular mechanisms in PI, provided promising biomarkers and suggested a molecular basis for therapeutic targets for this condition.

The preventive and therapeutic role of physical activity in knee osteoarthritis

The aim of this narrative review is to discuss the results of studies investigating the role of physical activity in knee osteoarthritis (OA). We also formulated two evidence-based exercise programs that could be prescribed to patients with symptomatic knee OA or after joint replacement. The PubMed and Google Scholar databases were searched for articles related to knee OA and physical activity. A total of 86 papers written in English and published from 1957 to 2021 were selected. Adapted physical activity, even at high intensity, does not appear to trigger or exacerbate knee OA; on the contrary, it may prevent obesity or lower limb muscle weakness, both of which are considered predisposing factors for the disease. In patients already diagnosed with knee OA, scientific evidence suggests that both land-based and aquatic activities combining aerobics, strength, and endurance programs are safe and effective. Physical interventions tailored to the patient may also accelerate recovery time after knee arthroplasty. Knee OA is a painful and disabling rheumatic disease that is very common in the elderly population. Pharmacotherapy has a modest effect in controlling disease progression, possibly due to the still limited understanding of OA pathogenesis. Non-pharmacologic interventions, including dietary and lifestyle changes and physical activity, may be more effective and safer than drugs in preventing or treating knee OA.

PTH (1-34) enhances the therapeutic effect of bone marrow mesenchymal stem cell-derived exosomes by inhibiting proinflammatory cytokines expression on OA chondrocyte repair in vitro

Background

The effects of bone marrow mesenchymal stem cells (BMSCs) during the treatment of cartilage damage have been proven to be attributed to paracrine mechanisms, particularly the effect of exosomes. Exosomes from different batches are inhomogeneous, and different treatment effects are observed between samples. The purpose of this research was to find more effective and homogeneous exosomes for the repair of chondrocytes in osteoarthritis (OA). We observed the potential effects and possible mechanisms of exosomes derived from parathyroid hormone (PTH) (1-34)-preconditioned BMSCs (Exo^PTH) in the alleviation of OA.

Materials and methods

Exosomes derived from BMSCs (Exo^BMSC) and Exo^PTH were isolated by differential centrifugation. Primary rat chondrocytes were used to establish the OA model by interleukin 1 beta (IL-1β) in vitro. The effects of these two types of exosomes on OA chondrocyte proliferation, migration, apoptosis, and extracellular matrix formation were measured and compared. We observed changes in IL-2, TNF-α, and IL-6 levels via Western blotting (WB), and quantitative real-time PCR (qRT–PCR).

Results

We successfully extracted Exo^BMSC and Exo^PTH and established an IL-1β-induced OA model in primary chondrocytes from rats. Our study showed that IL-2, TNF-α, and IL-6 levels increased significantly in OA chondrocytes; however, both Exo^BMSC and Exo^PTH reduced the levels of IL-2, TNF-α, and IL-6. In addition, Exo^PTH exhibited stronger anti-inflammatory effects. Exo^PTH had a more marked effect on proliferation, migration, and production of the extracellular matrix (Col-II) in OA chondrocytes than Exo^BMSC at 24 h.

Conclusion

Exo^PTH increased the migration, proliferation, and chondral matrix formation of OA chondrocytes in vitro. In OA chondrocyte therapy, the potential mechanism of Exo^PTH might involve the inhibition of production of proinflammatory cytokines. Although the two types of exosomes had some similar effects, most effects of Exo^PTH were better than those of Exo^BMSC, so Exo^PTH may have a better ability to alleviate OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02778-x.

Investigation of Behavior and Plasma Levels of Corticosterone in Restrictive- and Ad Libitum-Fed Diet-Induced Obese Mice

Diet-induced obesity (DIO) mice models are commonly used to investigate obesity-related health problems. Until now, only sparse data exist on the influence of DIO on behavior and stress hormones in mice. The present study investigates high-fat DIO with two different feeding regimes on behavioral parameters in mice. Various behavioral tests (open field, elevated plus maze, social interaction, hotplate) were performed with female BALB/c and male C57BL/6 mice after a feeding period of twelve weeks (restrictive vs. ad libitum and normal-fat diet vs. high-fat diet) to investigate levels of anxiety and aggression. BALB/c mice were DIO-resistant and therefore the prerequisite for the behavior analyses was not attained. C57BL/6 mice fed a high-fat diet had a significantly higher body weight and fat mass compared to C57BL/6 mice fed a control diet. Interestingly, the DIO C57BL/6 mice showed no changes in their aggression- or anxiety-related behavior but showed a significant change in the anxiety index. This was probably due to a lower activity level, as other ethological parameters did not show an altered anxiety-related behavior. In the ad libitum-fed DIO group, the highest corticosterone level was detected. Changes due to the feeding regime (restrictive vs. ad libitum) were not observed. These results provide a possible hint to a bias in the investigation of DIO-related health problems in laboratory animal experiments, which may be influenced by the lower activity level.

The Effects of 21-Day General Rehabilitation after Hip or Knee Surgical Implantation on Plasma Levels of Selected Interleukins, VEGF, TNF-α, PDGF-BB, and Eotaxin-1

Rehabilitation in osteoarthritis (OA) patients aims to reduce joint pain and stiffness, preserve or improve joint mobility, and improve patients’ quality of life. This study evaluated the effects of the 21-day individually adjusted general rehabilitation program in 36 OA patients 90 days after hip or knee replacement on selected interleukins (IL) and cytokines using the Bio-Plex® Luminex® system. Serum concentrations of almost all selected anti/pro-inflammatory markers: IL-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-15, and of some chemokines: macrophage inflammatory protein-1 alpha (MIP-1α/CCL3), and RANTES/CCL5, and of eotaxin-1/CCL11, the vascular endothelial growth factor (VEGF) significantly increased, whereas basic fibroblast growth factor (FGF basic) significantly decreased after the 21-day general rehabilitation. The levels of interferon-γ induced protein 10 (IP-10), MIP-1β/CCL4, macrophage/monocyte chemoattractant protein-1 (MCP-1/CCL2 (MCAF)), granulocyte macrophage-colony stimulating factor (GM-CSF), platelet-derived growth factor-BB (PDGF-BB), and granulocyte colony-stimulating factor (G-CSF) remained unchanged. There were no changes in pro-inflammatory cytokines levels: tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ), and IL-12 (p70)) after the 21-day general rehabilitation, indicating the stable and controlled inflammatory status of osteoarthritis patients. Significantly higher levels of anti-inflammatory factors after 21 days of moderate physical activity confirm the beneficial outcome of the applied therapy. The increased level of IL-6 after the rehabilitation may reflect its anti-inflammatory effect in osteoarthritis patients.

Chaenomeles Fructus (CF), the Fruit of Chaenomeles sinensis Alleviates IL-1β Induced Cartilage Degradation in Rat Articular Chondrocytes

Osteoarthritis (OA) causes persistent pain, joint dysfunction, and physical disability. It is the most prevalent type of degenerative arthritis, affecting millions of people worldwide. OA is currently treated with a focus on pain relief, inflammation control, and artificial joint surgery. Hence, a therapeutic agent capable of preventing or delaying the progression of OA is needed. OA is strongly associated with the degeneration of the articular cartilage and changes in the ECM, which are primarily associated with a decrease in proteoglycan and collagen. In the progress of articular cartilage degradation, catabolic enzymes, such as matrix metalloproteinases (MMPs), are activated by IL-1β stimulation. Given the tight relationship between IL-1β and ECM (extra-cellular matrix) degradation, this study examined the effects of Chaenomeles Fructus (CF) on IL-1β-induced OA in rat chondrocytes. The CF treatment reduced IL-1β-induced MMP3/13 and ADAMTS-5 production at the mRNA and protein levels. Similarly, CF enhanced col2a and aggrecan accumulation and chondrocyte proliferation. CF inhibited NF-κB (nuclear factor kappa B) activation, nuclear translocation induced by IL-1β, reactive oxygen species (ROS) production, and ERK phosphorylation. CF demonstrated anti-OA and articular regeneration effects on rat chondrocytes, thus, suggesting that CF is a viable and fundamental therapeutic option for OA.

Impact of losing adipose tissue on outcomes from PD-1/PD-L1 inhibitor monotherapy in non-small cell lung cancer

Background

Adipose tissue induces inflammation, which desensitizes the efficacy of immunotherapy. However, several reports show that the therapeutic effect of programed cell death 1 (PD‐1)/programed death‐ligand 1 (PD‐L1) inhibitor(s) monotherapy is significantly better in obese patients. Therefore, the effect of adipose tissue on immunotherapy is unclear.

Methods

In this study, we retrospectively reviewed patients with advanced non‐small cell lung cancer (NSCLC) who received PD‐1/PD‐L1 inhibitor monotherapy between May 2016 and December 2018. We classified patients into total adipose tissue maintenance or loss groups according to adipose tissue change during the 6 months before treatment and compared the therapeutic effect of PD‐1/PD‐L1 inhibitors between these groups along with the presence or absence of cachexia, a poor prognostic factor.

Results

Of the 74 patients, 40 (54.1%) were cachexic. Among cachexic patients, we found no clear difference in the overall response rate (ORR) and progression‐free survival (PFS) between the total adipose tissue maintenance and loss group. However, among noncachexic patients, the total adipose tissue loss group had a higher ORR (64.7% vs. 23.5%, p < 0.05) and longer PFS (18.5 months vs. 2.86 months, p = 0.037) than the maintenance group.

Conclusions

This study showed that decreasing adipose tissue without cachexia might favor the therapeutic effects of immunotherapy.

High-Fat Diet-Induced Dysregulation of Immune Cells Correlates with Macrophage Phenotypes and Chronic Inflammation in Adipose Tissue

Obesity is a complex disease associated with various metabolic abnormalities, cardiovascular diseases, and low-grade chronic inflammation. Inflammation associated with T helper 1 (Th1) immune cells is dominant in adipose tissue (AT) and exerts metabolically deleterious impacts. The precise mechanism of alteration in AT immune system and its effect on metabolic homeostasis remains unclear. In this study, we investigated how a high-fat diet (HFD) alters the AT immune response and influences inflammation during obesity. HFD consumption amends the metabolic parameters, including body weight, glucose, and insulin levels. We observed increased infiltration of Th17 cells, a subset of dendritic cells (CD103+), and M1 macrophages in AT of mice fed HFD compared to those fed a normal diet (ND). In mice that were fed HFD, we also observed a reduction in regulatory T cells (Tregs) relative to the numbers of these cells in mice fed ND. Corresponding with this, mice in the HFD group exhibited higher levels of proinflammatory cytokines and chemokines than those in the ND group. We also observed alterations in signaling pathways, including increased protein expression of IRF3, TGFβ1, and mRNA expression of IL-6, KLF4, and STAT3 in the AT of the mice fed HFD as compared to those fed ND. Further, HFD-fed mice exhibited decreased protein expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) compared to mice fed ND, suggesting that PPAR-γ functions as a negative regulator of Th17 cell differentiation. These results suggest that HFD induces increased levels of inflammatory cytokines and key immune cells, including Th17, M1 macrophages, and CD103+ dendritic cells, and reduces levels of PPAR-γ and Tregs to sustain AT inflammation. This study supports the notion that dysregulation of Th17/Tregs, which polarizes macrophages towards M1 phenotypes in part through TGFβ1-IRF3-STAT3 and negatively regulates PPAR-γ mediated pathways, results in AT inflammation during obesity.

Engineering Closed-Loop, Autoregulatory Gene Circuits for Osteoarthritis Cell-Based Therapies

PURPOSE OF REVIEW

Genetic engineering offers the possibility to simultaneously target multiple cellular pathways in the joints affected by osteoarthritis (OA). The purpose of this review is to summarize the ongoing efforts to develop disease-modifying osteoarthritis drugs (DMOADs) using genetic engineering, including targeting approaches, genome editing techniques, and delivery methods.

RECENT FINDINGS

Several gene circuits have been developed that reprogram cells to autonomously target inflammation, and their efficacy has been demonstrated in chondrocytes and stem cells. Gene circuits developed for metabolic disorders, such as those targeting insulin resistance and obesity, also have the potential to mitigate the impact of these conditions on OA onset and/or progression. Despite the strides made in characterizing the inflammatory environment of the OA joint, our incomplete understanding of how the multiple regulators interact to control signal transduction, gene transcription, and translation to protein limits the development of targeted disease-modifying therapeutics. Continuous advances in targeted genome editing, combined with online toolkits that simplify the design and production of gene circuits, have the potential to accelerate the discovery and clinical application of multi-target gene circuits with disease-modifying properties for the treatment of OA.

Evaluation of the Pro-, Anti-Inflammatory, and Anabolic Effects of Autologous Platelet-Rich Gel Supernatants in an in vitro Coculture System of Canine Osteoarthritis

There are scarce in vitro studies indicating the basic mechanisms of why platelet-rich plasma (PRP) is useful in the clinical management of dogs with naturally occurring OA. Methods. Cartilage and synovial membrane explants from six dogs were challenged with lipopolysaccharide (LPS) and cultured for 48 h with platelet-poor gel supernatant (PPGS) and platelet-rich gel supernatant (PRGS) at concentrations of 25 and 50%, respectively. The tissue explants challenged with LPS were cocultured over 48 h and culture media were sampled at 1 and 48 h for the determination of IL-1β, IL-10, hyaluronan, TGF-β1, and PDGF-BB by ELISA. Results. IL-1β concentrations were significantly higher in tissue explant groups cultured for 48 h with PRGS at 50% and with PPGS at 25% when compared to the remaining experimental groups at any time. IL-10 and HA presented similar concentrations in all evaluated groups at any time. TGF-β1 and PDGF-BB presented higher concentrations in the culture media of tissue explants cultured with PPGS and PRGS at 50%, which diminished with time. Conclusions. Both PPGS and PRGS at both concentrations showed a limited biological effect on cartilage and synovial membrane explants in coculture with LPS. Even PPGS at 25% and PRGS at 50% exhibited proinflammatory effects on these tissues at 48 h.

Longitudinal association of infrapatellar fat pad signal intensity alteration with biochemical biomarkers in knee osteoarthritis

OBJECTIVE

To explore the longitudinal association of quantitative infrapatellar fat pad (IPFP) signal intensity alteration with OA-related biomarkers.

METHODS

Eighteen OA-related biochemical biomarkers of 600 knee OA participants in the Foundation for the National Institutes of Health OA Biomarkers Consortium (FNIH) study were extracted. The quantitative IPFP signal intensity measures were acquired based on magnetic resonance imaging, including mean value [Mean (IPFP)] and standard deviation [sDev (IPFP)] of the whole IPFP signal intensity, median value [Median (H)] and upper quartile value [UQ (H)] of high signal intensity, the ratio of volume of high signal intensity to volume of whole IPFP signal intensity [Percentage (H)] and Clustering factor (H). The linear mixed-effect model was applied to determine the longitudinal associations between IPFP signal intensity alteration and biochemical biomarkers over 2 years.

RESULTS

All IPFP measures except for Clustering factor (H) were positively associated with urine collagenase-cleaved type II collagen neoepitope (uC2C), urine C-terminal cross-linked telopeptide of type II collagen (uCTX-II), urine C-terminal cross-linked telopeptide of type I collagen-α (uCTX-Iα) and urine N-terminal cross-linked telopeptide of type I collagen (uNTX-I). Mean (IPFP), Median (H) and Percentage (H) were positively associated with the nitrated form of an epitope located in the triple helix of type II collagen (Coll2-1 NO2). Mean (IPFP), Median (H) and UQ (H) were positively associated with sCTX-I and uCTX-Iβ. Positive associations between sDev (IPFP), Percentage (H) and serum hyaluronic acid (sHA) were found.

CONCLUSION

Our results suggest a role of IPFP signal intensity alteration in joint tissue remodelling on a molecular level.

Anti-Obesity and Anti-Hyperglycemic Effects of Meretrix lusoria Protamex Hydrolysate in ob/ob Mice

Meretrix lusoria (M. lusoria) is an economically important shellfish which is widely distributed in South Eastern Asia that contains bioactive peptides, proteins, and enzymes. In the present study, the extracted meat content of M. lusoria was enzymatic hydrolyzed using four different commercial proteases (neutrase, protamex, alcalase, and flavourzyme). Among the enzymatic hydrolysates, M. lusoria protamex hydrolysate (MLPH) fraction with MW ≤ 1 kDa exhibited the highest free radical scavenging ability. The MLPH fraction was further purified and an amino acid sequence (KDLEL, 617.35 Da) was identified by LC-MS/MS analysis. The purpose of this study was to investigate the anti-obesity and anti-hyperglycemic effects of MLPH containing antioxidant peptides using ob/ob mice. Treatment with MLPH for 6 weeks reduced body and organ weight and ameliorated the effects of hepatic steatosis and epididymal fat, including a constructive effect on hepatic and serum marker parameters. Moreover, hepatic antioxidant enzyme activities were upregulated and impaired glucose tolerance was improved in obese control mice. In addition, MLPH treatment markedly suppressed mRNA expression related to lipogenesis and hyperglycemia through activation of AMPK phosphorylation. These findings suggest that MLPH has anti-obesity and anti-hyperglycemic potential and could be effectively applied as a functional food ingredient or pharmaceutical.

A Retrospective Analysis of 1,595 Cases: Comparing the Characteristics of Total Knee Arthroplasty between Tibetans Living in the Plateau and Han of the Sichuan Basin

Background

Total knee arthroplasty is an effective treatment for end-stage knee arthritis. Studies' date have shown that the demand for knee replacements continues to increase worldwide. Although racial disparities have been previously reported in the utilization of total knee arthroplasty in western countries, however, there are few similar studies in China.

Objectives

Retrospective analysis of medical records identified the characteristics of Tibetan patients who had undergone total knee arthroplasty living in plateau and their differences with Hans living in Sichuan Basin.

Methods

The patients with unilateral primary total knee arthroplasty in Sichuan Orthopedic Hospital from 2015 to 2020 were enrolled. Analyze and compare the demographic characteristics (age, body mass index, and occupation) and pathogenesis characteristics (disease duration, exacerbation period, treatment methods, etc.) of the plateau Tibetans and the Hans of the Sichuan Basin.

Results

1595 eligible patients were reviewed, including 541 Tibetan patients and 1054 Han patients, The average age of Tibetan patients was lower than that of Han patients (P < 0.001); the average BMI index of Tibetan patients was higher than that of Han patients (P < 0.001). And obese people account for more; the occupational distribution of Tibetan patients is more concentrated, mainly farmers. Tibetan patients have a longer course of disease than Han patients (P < 0.001).

Conclusions

The social background and geographical environment of the Tibetan population are different from those of the Han. Tibetans living on plateaus have an earlier illness, a longer course of illness, a more obvious trend of younger, age and fewer opportunities for regular treatment during the illness.

What Have Failed, Interrupted, and Withdrawn Antibody Therapies in Multiple Sclerosis Taught Us?

In the past two decades, monoclonal antibodies (mAbs) have revolutionized the treatment of multiple sclerosis (MS). However, a remarkable number of mAbs failed due to negative study results were withdrawn because of unexpected serious adverse events (SAEs) or due to studies being halted for other reasons. While trials with positive outcomes are usually published in prestigious journals, negative trials are merely published as abstracts or not at all. This review summarizes MS mAbs that have either failed in phase II-III trials, have been interrupted for various reasons, or withdrawn from the market since 2015. The main conclusions that can be drawn from these 'negative' experiences are as follows. mAbs that have been proven to be safe in other autoimmune conditions, will not have the same safety profile in MS due to immunopathogenetic differences in these diseases (e.g., daclizumab). Identification of SAEs in clinical trials is difficult highlighting the importance of phase IV studies. Memory B cells are central players in MS immunopathogenesis (e.g., tabalumab). The pathophysiological mechanisms of disease progression are independent of leukocyte 'outside-in' traffic which drives relapses in MS. Therefore, therapies for progressive MS must be able to sufficiently cross the blood-brain barrier. Sufficiently long trial duration and multicomponent outcome measures are important for clinical studies in progressive MS. The success of trials on remyelination-promoting therapies mainly depends on the sufficient high dose of mAb, the optimal readout for 'proof of concept', time of treatment initiation, and appropriate selection of patients. Failed strategies are highly important to better understand assumed immunopathophysiological mechanisms and optimizing future trial designs.

Tangeretin suppresses osteoarthritis progression via the Nrf2/NF-κB and MAPK/NF-κB signaling pathways

BACKGROUND

Osteoarthritis (OA) is a globally prevalent degenerative disease characterized by extracellular matrix (ECM) degradation and inflammation. Tangeretin is a natural flavonoid that has anti-inflammatory properties. Studies have not explored whether tangeretin modulates OA development.

PURPOSE

The aim of this study was to explore the potential effects and mechanism underlying the anti-OA properties of tangeretin.

STUDY DESIGN

Effects of tangeretin on OA were detected in chondrocytes and OA mouse model.

METHODS

Protective effects of tangeretin on murine articular chondrocytes treated with interleukin-1β (IL-1β) were evaluated using qPCR, western blot analysis, ELISA, ROS detection and immunofluorescent staining in vitro. Healing effect of tangeretin on cartilage degradation in mice was assessed through X-ray imaging, histopathological analysis, immunohistochemical staining and immunofluorescent staining in vivo.

RESULTS

Tangeretin suppressed IL-1β-mediated inflammatory mediator secretion and degradation of ECM in chondrocytes. The results showed that tangeretin abrogated destabilized medial meniscus (DMM)-induced cartilage degradation in mice. Mechanistic studies showed that tangeretin suppressed OA development by downregulating activation of NF-κB by activating Nrf2/HO-1 axis and suppressing MAPK signaling pathway.

CONCLUSION

Tangeretin abrogates OA progression by inhibiting inflammation as well as ECM degradation in chondrocytes and animal models. Effects of tangeretin are mediated through Nrf2/NF-κB and the MAPK/NF-κB pathways. Thus, tangeretin is a potential therapeutic agent for osteoarthritis treatment.

Aging of the Immune System: Focus on Natural Killer Cells Phenotype and Functions

Aging is the greatest risk factor for nearly all major chronic diseases, including cardiovascular diseases, cancer, Alzheimer’s and other neurodegenerative diseases of aging. Age-related impairment of immune function (immunosenescence) is one important cause of age-related morbidity and mortality, which may extend beyond its role in infectious disease. One aspect of immunosenescence that has received less attention is age-related natural killer (NK) cell dysfunction, characterized by reduced cytokine secretion and decreased target cell cytotoxicity, accompanied by and despite an increase in NK cell numbers with age. Moreover, recent studies have revealed that NK cells are the central actors in the immunosurveillance of senescent cells, whose age-related accumulation is itself a probable contributor to the chronic sterile low-grade inflammation developed with aging (“inflammaging”). NK cell dysfunction is therefore implicated in the increasing burden of infection, malignancy, inflammatory disorders, and senescent cells with age. This review will focus on recent advances and open questions in understanding the interplay between systemic inflammation, senescence burden, and NK cell dysfunction in the context of aging. Understanding the factors driving and enforcing NK cell aging may potentially lead to therapies countering age-related diseases and underlying drivers of the biological aging process itself.

Concentration of Selected Metalloproteinases and Osteocalcin in the Serum and Synovial Fluid of Obese Women with Advanced Knee Osteoarthritis

The aim of the study was to evaluate the levels of selected MMPs (matrix metalloproteinases) and osteocalcin in the serum and synovial fluid of obese women with osteoarthritis and their correlations with clinical status. The studied group consisted of 39 overweight females undergoing primary total knee arthroplasty due to osteoarthritis (OA). The staging of knee OA was evaluated according to the Ahlbӓck and Kellgren–Lawrence scores. Synovial fluid and peripheral blood samples were obtained. The levels of selected MMPs and osteocalcin were assessed using commercial ELISA kits. The mean value of MMP3 was significantly higher in patients with more advanced disease in both serum (p = 0.0067) and synovial fluid (p = 0.0328). The pro-MMP13 level tended to be higher in synovial fluid in the case of more advanced stages (p = 0.0882), with no tendency regarding the serum level (p = 0.9595). The synovial level of pro-MMP1 was significantly correlated with the synovial concentration of MMP9 and MMP3. The synovial level of MMP9 also showed a significant correlation with the synovial level of MMP3 and pro-MMP13. Furthermore, it was found that the serum level of MMP3 was significantly correlated with the synovial pro-MMP13 level. A correlation between the osteocalcin level in serum and its synovial level was determined. The serum MMP9 level showed a significant correlation with BMI, whereas the synovial MMP9 level was notably correlated with age. Our results showed that the levels of MMP3, MMP9, and pro-MMP13 increased in more advanced radiological stages of OA, indicating the underlying inflammatory process of OA.

Bilobalide Exerts Anti-Inflammatory Effects on Chondrocytes Through the AMPK/SIRT1/mTOR Pathway to Attenuate ACLT-Induced Post-Traumatic Osteoarthritis in Rats

Although osteoarthritis (OA) significantly affects the quality of life of the elderly, there is still no effective treatment strategy. The standardized Ginkgo biloba L. extract preparation has been shown to have a wide range of therapeutic effects. Bilobalide, a unique ingredient of Ginkgo biloba, has anti-inflammatory and antioxidant pharmacological properties, but its mechanism of action on OA remains unknown. In this study, we investigated the effects of bilobalide on the development of OA through in vivo and in vitro experiments, as well as its potential anti-inflammatory mechanisms. The in vitro experiments demonstrated that bilobalide significantly inhibited the production of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and matrix metalloproteinase 13 (MMP13) in ATDC5 chondrocytes induced by Interleukin-1β (IL-1β). At the molecular level, bilobalide induced chondrocyte autophagy by activating the AMPK/SIRT1/mTOR signaling pathway, which increased the expression of autophagy-related Atg genes, up-regulated the expression of LC3 protein, and reduced the expression of the p62 protein. In vivo, bilobalide exerted significant anti-inflammatory and anti-extracellular matrix (ECM) degradation effects in a rat model of post-traumatic OA (PTOA) induced by anterior cruciate ligament transection (ACLT). Bilobalide could relieve joint pain in PTOA rats, inhibit the expression of iNOS and COX-2 protein in cartilage via the AMPK/SIRT1/mTOR pathway, and reduce the level of ECM degradation biomarkers in serum. In conclusion, bilobalide exhibits vigorous anti-inflammatory activity, presenting it as an interesting potential therapeutic agent for OA.

Circ-LRP1B functions as a competing endogenous RNA to regulate proliferation, apoptosis and oxidative stress of LPS-induced human C28/I2 chondrocytes

Circular RNAs (circRNAs) are crucial for the pathogenesis of human diseases, including osteoarthritis (OA). Here, we set to elucidate the biological action of circ-LRP1B in OA pathogenesis. Human C28/I2 chondrocytes were stimulated by lipopolysaccharide (LPS). Circ-LRP1B, nuclear factor, erythroid 2 like 1 (NRF1) and microRNA (miR)-34a-5p were quantified by quantitative real-time PCR (qRT-PCR) or immunoblotting. Cell viability, proliferation, and apoptosis abilities were gauged by MTT, 5-Ethynyl-2'-Deoxyuridine (EdU) staining, and flow cytometry assays, respectively. Direct relationship between miR-34a-5p and circ-LRP1B or NRF1 was validated by RNA pull-down and dual-luciferase reporter assays. Circ-LRP1B was found to be underexpressed in OA cartilage and LPS-stimulated C28/I2 chondrocytes. Enforced expression of circ-LRP1B promoted cell proliferation, and repressed apoptosis and oxidative stress, as well as impacted OA-specific hallmarks expression of LPS-stimulated C28/I2 cells. NRF1 was identified as a downstream effector of circ-LRP1B function. Moreover, NRF1 was identified as a miR-34a-5p target in LPS-stimulated C28/I2 cells. Circ-LRP1B acted as a competing endogenous RNA (ceRNA) for miR-34a-5p to involve the post-transcriptional regulation of NRF1 expression. Furthermore, the effects of circ-LRP1B overexpression partly depended on the reduction of available miR-34a-5p. These findings demonstrate that circ-LRP1B functions as a ceRNA to regulate the proliferation, apoptosis and oxidative stress of LPS-stimulated human C28/I2 chondrocytes by miR-34a-5p/NRF1 network.

Gene expression analysis of subchondral bone, cartilage, and synovium in naturally occurring equine palmar/plantar osteochondral disease

Osteoarthritis (OA) is a disease of the entire joint but the relationship between pathological events in various joint tissues is poorly understood. We examined concurrent changes in bone, cartilage, and synovium in a naturally occurring equine model of joint degeneration. Joints (n = 64) were grossly assessed for palmar/plantar osteochondral disease (POD) in racehorses that required euthanasia for unrelated reasons and assigned a grade of 0 (n = 34), 1 (n = 17), 2 or 3 (n = 13) using a recognized grading scheme. Synovium, cartilage, and subchondral bone were collected for histological and gene expression analysis. Relations between POD grade, cartilage histological score, and gene expression levels were examined using one-way analysis of variance or Kruskal-Wallis test and Spearman's correlation coefficient with corrections for multiple comparisons. Cartilage histological score increased in joints with POD grade 1 (p = 0.002) and 2 or 3 (p < 0.001) compared to 0. At grade 1, expression of COL1A1, COL2A1, and MMP1 increased and BGN decreased in subchondral bone while expression of BGN and ACAN decreased in cartilage. These changes further progressed at grades 2 and 3. POD grades 2 and 3 were associated with decreased expression of osteoclast inhibitor OPG and increased markers of cartilage degeneration (MMP13, COL1A1). Expression of the vascular endothelial growth factor decreased with POD grade and negatively correlated with cartilage histological score. Synovium showed no histological or transcriptomic changes related to pathology grade. Cartilage degeneration in POD is likely to be secondary to remodeling of the subchondral bone. Limited activation of proinflammatory and catabolic genes and moderate synovial pathology suggests distinct molecular phenotype of POD compared with OA.

Farnesoid X receptor agonist attenuates subchondral bone osteoclast fusion and osteochondral pathologies of osteoarthritis via suppressing JNK1/2/NFATc1 pathway

Osteoarthritis (OA) is a prevalent degenerative disease of the joint, featured by articular cartilage destruction and subchondral bone marrow lesions. Articular cartilage and subchondral bone constitute an osteochondral unit that guarantees joint homeostasis. During OA initiation, activated osteoclasts in subchondral bone ultimately result in impaired capacities of the subchondral bone in response to mechanical stress, followed by the degradation of overlying articular cartilage. Thus, targeting osteoclasts could be a potential therapeutic option for treating OA. Here, we observed that farnesoid X receptor (FXR) expression and osteoclast fusion and activity in subchondral bone were concomitantly changed during early-stage OA in the OA mouse model established by anterior cruciate ligament transection (ACLT). Then, we explored the therapeutic effects of FXR agonist GW4064 on the osteochondral pathologies in ACLT mice. We showed that GW4064 obviously ameliorated subchondral bone deterioration, associated with reduction in tartrate-resistant acid phosphatase (TRAP) positive multinuclear osteoclast number, as well as articular cartilage degradation, which were blocked by the treatment with FXR antagonist Guggulsterone. Mechanistically, GW4064 impeded osteoclastogenesis through inhibiting subchondral bone osteoclast fusion via suppressing c-Jun N-terminal kinase (JNK) 1/2/nuclear factor of activated T-cells 1 (NFATc1) pathway. Taken together, our results present evidence for the protective effects of GW4064 against OA by blunting osteoclast-mediated aberrant subchondral bone loss and subsequent cartilage deterioration. Therefore, GW4064 demonstrates the potential as an alternative therapeutic option against OA for further drug development.

An osteoarthritis subtype characterized by synovial lipid metabolism disorder and fibroblast-like synoviocyte dysfunction

Background

The heterogeneity of osteoarthritis (OA) significantly limits the effectiveness of pharmacological treatments in an unselected patient population. In this context, the identification of OA subtypes is meaningful for the development of therapies that target specific types of OA pathogenesis.

Methods

Expression array profiles of 70 OA and 36 control synovial samples were extracted from the GEO database. Unsupervised consensus clustering was performed based on the most variable genes to identify OA subclusters. Next, Joint samples from OA patients were obtained. We divided the OA patient into two subpopulations according to synovial ADCY7 levels. Synovium and cartilage samples from different OA subpopulations were evaluated. In addition, we established a high-fat diet (HFD)-induced rat OA model. We evaluated OA progression, lipid metabolism, synovitis and fibroblast-like synoviocytes (FLS) function in this HFD-induced OA model.

Results

70 OA patients were categorized into three distinct subclusters. We noted that one subcluster was characterized by synovial lipid metabolism disorder GO terms. We further identified the most noticeable KEGG pathway “Regulation of lipolysis in adipocytes” in this subcluster as well as the most significantly differentially expressed gene, ADCY7. We found that the ADCY7 high expressing group (32.6%) exhibited features of synovial inflammatory lipolysis epithelial-mesenchymal transition (EMT) tendency, as well as faster join space narrowing. The HFD induced OA-like degeneration in rat joints. We observed similar synovial inflammatory lipolysis and EMT in FLS, characterized by higher proliferative and invasive activity and elevated proinflammatory and procatabolic properties. ADCY7 was highly expressed in the synovium of the HFD-OA model rats and the inhibition of ADCY7 effectively attenuated these HFD-induced degenerative changes as well as synovial inflammatory lipolysis and FLS dysfunction. In HFD-FLSs, ADCY7 promoted the phosphorylation of PKA as well as its downstream lipid droplet-associated protein PLIN1 and hormone-sensitive lipase (HSL). The inhibition of PKA largely alleviated ADCY7-mediated HFD-FLS dysfunction.

Conclusions

We described a synovial EMT and lipid metabolism disorder in the pathogenesis of OA. This novel mechanism may represent a currently undefined OA subtype. ADCY7 is a potential molecular marker of this pathomechanism.

The Translational potential of this article

Utilizing synovial samples from OA patients, we identified a subpopulation with high ADCY7 expression. This may represent a currently undefined OA subtype and explain the clinical phenomenon of more severe synovial inflammation in obese OA patients. In addition, we established an HFD-induced OA rat model and found an upregulation of ADCY7 in the synovium. We confirmed that the inhibition of ADCY7 could effectively attenuate HFD-induced degenerative changes as well as the inflammatory lipolysis and FLS dysfunction observed in the rat model. This suggests that ADCY7 and its downstream pathways are potential pharmacological targets for treating this lipid-metabolism-disorder-related OA mechanism.

The Role of Medicinal and Aromatic Plants against Obesity and Arthritis: A Review

Obesity is a significant health concern, as it causes a massive cascade of chronic inflammations and multiple morbidities. Rheumatoid arthritis and osteoarthritis are chronic inflammatory conditions and often manifest as comorbidities of obesity. Adipose tissues serve as a reservoir of energy as well as releasing several inflammatory cytokines (including IL-6, IFN-γ, and TNF-α) that stimulate low-grade chronic inflammatory conditions such as rheumatoid arthritis, osteoarthritis, diabetes, hypertension, cardiovascular disorders, fatty liver disease, oxidative stress, and chronic kidney diseases. Dietary intake, low physical activity, unhealthy lifestyle, smoking, alcohol consumption, and genetic and environmental factors can influence obesity and arthritis. Current arthritis management using modern medicines produces various adverse reactions. Medicinal plants have been a significant part of traditional medicine, and various plants and phytochemicals have shown effectiveness against arthritis and obesity; however, scientifically, this traditional plant-based treatment option needs validation through proper clinical trials and toxicity tests. In addition, essential oils obtained from aromatic plants are being widely used as for complementary therapy (e.g., aromatherapy, smelling, spicing, and consumption with food) against arthritis and obesity; scientific evidence is necessary to support their effectiveness. This review is an attempt to understand the pathophysiological connections between obesity and arthritis, and describes treatment options derived from medicinal, spice, and aromatic plants.

Aerobic exercise is an independent determinant of levels of inflammation and oxidative stress in middle-aged obese females

The purpose of this study was to investigate the effects of a 4-week moderate-intensity aerobic exercise on changes of body composition and markers of inflammation and oxidative stress independent from weight loss in middle-aged obese females. Thity-five obese females were randomly assigned to either an exercise (EX, N=16) or control (CON, N=19) group. The EX performed moderate intensity aerobic exercise on the treadmill for 60 min at 55% of maximal oxygen consumption (VO_2max) for 4 weeks (3 days/wk). Body composition measurement with dual-energy x-ray absorptiometry and blood collection were conducted before and after the 4-weeks intervention. Blood samples were used to measure levels of tumor necrosis factor-alpha (TNF-α), C-reactive protein, adiponectin, total antioxidant status (TAS), and 8-hydroxydeoxyguanosine. Four weeks of aerobic exercise intervention significantly increased VO_2max in EX (P<0.001). EX also observed a decrease in TNF-α (P=0.033) and an increase in TAS (P=0.028) without changes in body weight and fat mass after 4 weeks of aerobic exercise training. No changes were observed in CON after the intervention. Results of this study indicate that moderate aerobic exercises may contribute, at least a part, to reductions of inflammation and oxidative stress independently from fat loss. Therefore, it may reduce risks of obesity-associated disorders in middle-aged obese females.

p38MAPK Signaling Pathway in Osteoarthritis: Pathological and Therapeutic Aspects

Osteoarthritis (OA) is an aging-related joint disease, pathologically featured with degenerated articular cartilage and deformation of subchondral bone. OA has become the fourth major cause of disability in the world, imposing a huge economic burden. At present, the pathogenesis and pathophysiology of OA are still unclear. Complex regulating networks containing different biochemical signaling pathways are involved in OA pathogenesis and progression. The p38MAPK signaling pathway is a member of the MAPK signaling pathway family, which participates in the induction of cellular senescence, the differentiation of chondrocytes, the synthesis of matrix metalloproteinase (MMPs) and the production of pro-inflammatory factors. In recent years, studies on the regulating role of p38MAPK signaling pathway and the application of its inhibitors have attracted growing attention, with an increasing number of in vivo and in vitro studies. One interesting finding is that the inhibition of p38MAPK could suppress chondrocyte inflammation and ameliorate OA, indicating its therapeutic role in OA treatment. Based on this, we reviewed the mechanisms of p38MAPK signaling pathway in the pathogenesis of OA, hoping to provide new ideas for future research and OA treatment.

Interplay Between Iron Overload and Osteoarthritis: Clinical Significance and Cellular Mechanisms

There are multiple diseases or conditions such as hereditary hemochromatosis, hemophilia, thalassemia, sickle cell disease, aging, and estrogen deficiency that can cause iron overload in the human body. These diseases or conditions are frequently associated with osteoarthritic phenotypes, such as progressive cartilage degradation, alterations in the microarchitecture and biomechanics of the subchondral bone, persistent joint inflammation, proliferative synovitis, and synovial pannus. Growing evidences suggest that the conditions of pathological iron overload are associated with these osteoarthritic phenotypes. Osteoarthritis (OA) is an important complication in patients suffering from iron overload-related diseases and conditions. This review aims to summarize the findings and observations made in the field of iron overload-related OA while conducting clinical and basic research works. OA is a whole-joint disease that affects the articular cartilage lining surfaces of bones, subchondral bones, and synovial tissues in the joint cavity. Chondrocytes, osteoclasts, osteoblasts, and synovial-derived cells are involved in the disease. In this review, we will elucidate the cellular and molecular mechanisms associated with iron overload and the negative influence that iron overload has on joint homeostasis. The promising value of interrupting the pathologic effects of iron overload is also well discussed for the development of improved therapeutics that can be used in the field of OA.

Cartilage tissue engineering: From proinflammatory and anti‑inflammatory cytokines to osteoarthritis treatments (Review)

Osteoarthritis (OA), one of the most common joint diseases, is characterized by fibrosis, rhagadia, ulcers and attrition of articular cartilage due to a number of factors. The etiology of OA remains unclear, but its occurrence has been associated with age, obesity, inflammation, trauma and genetic factors. Inflammatory cytokines are crucial for the occurrence and progression of OA. The intra-articular proinflammatory and anti-inflammatory cytokines jointly maintain a dynamic balance, in accordance with the physiological metabolism of articular cartilage. However, dynamic imbalance between proinflammatory and anti-inflammatory cytokines can cause abnormal metabolism in knee articular cartilage, which leads to deformation, loss and abnormal regeneration, and ultimately destroys the normal structure of the knee joint. The ability of articular cartilage to self-repair once damaged is limited, due to its inability to obtain nutrients from blood vessels, nerves and lymphatic vessels, as well as limitations in the extracellular matrix. There are several disadvantages inherent to conventional repair methods, while cartilage tissue engineering (CTE), which combines proinflammatory and anti-inflammatory cytokines, offers a new therapeutic approach for OA. The aim of the present review was to examine the proinflammatory factors implicated in OA, including IL-1β, TNF-α, IL-6, IL-15, IL-17 and IL-18, as well as the key anti-inflammatory factors reducing OA-related articular damage, including IL-4, insulin-like growth factor and TGF-β. The predominance of proinflammatory over anti-inflammatory cytokine effects ultimately leads to the development of OA. CTE, which employs mesenchymal stem cells and scaffolding technology, may prevent OA by maintaining the homeostasis of pro- and anti-inflammatory factors.

Baicalein Alleviates Osteoarthritis Progression in Mice by Protecting Subchondral Bone and Suppressing Chondrocyte Apoptosis Based on Network Pharmacology

As life expectancy increases, Osteoarthritis (OA) is becoming a more frequently seen chronic joint disease. The main characteristics of OA are loss of articular cartilage, subchondral bone sclerosis, and synovial inflammation. Baicalein (Bai), a traditional Chinese medicine extracted from Scutellaria baicalensis Georgi, has been demonstrated to exert notable anti-inflammatory effects in previous studies, suggesting its potential effect in the treatment of OA. In this study, we first predicted the action targets of Bai, mapped target genes related to OA, identified potential anti-OA targets for Bai, performed gene ontology (GO) enrichment, and KEGG signaling pathway analyses of the action targets, and analyzed the molecular docking of key Bai targets. Additionally, the effect and potential mechanism of Bai against OA were verified in mouse knee OA models induced by destabilized medial meniscus (DMM) surgery. GO and KEGG analyses showed that 19 anti-OA targets were mainly involved in the response to oxidative stress, the response to hypoxia and apoptosis, and the PI3K-Akt and p53 signaling pathways. Molecular docking results indicated that BAX, BCL 2, and Caspase 3 enriched in the apoptotic signaling pathway have high binding affinity with Bai. Validation experiments showed that Bai can significantly attenuate the loss of articular cartilage (OARSI score), suppress synovial inflammation (synovitis score), and ameliorate subchondral bone resorption measured by micro-CT. In addition, Bai notably inhibited the expression of apoptosis-related proteins in articular cartilage (BAX, BCL 2, and Caspase 3). By combining network pharmacology with experimental validation, our study identifies and verifies the importance of the apoptotic signaling pathway in the treatment of OA by Bai. Bai may have promising application and potential therapeutic value in OA treatment.

Folic Acid Attenuates High-Fat Diet-Induced Osteoporosis Through the AMPK Signaling Pathway

Objective: Obesity caused by a high-fat diet (HFD) will expand adipose tissue and cause chronic low-grade systemic inflammation, leading to osteoporosis. Folic acid (FA) is a water-soluble vitamin that plays an essential role in regulating blood lipids and antioxidants. However, the effects and underlying mechanisms of FA in osteoporosis induced by an HFD remain poorly understood. This study aimed to investigate the effect of FA on bone health by using HFD-induced osteoporosis mice. Materials and Methods: Mice were fed a normal diet, HFD or an HFD supplemented with FA (20 μg/ml in drinking water) for 16 weeks. Throughout the 16 weeks study period, the rats were weighed once every week. GTT, ITT and lipid indexes were detected to evaluate the effects of FA on lipid metabolism in the HFD-fed mice. Morphological and structural changes of the femur and tibial bone were observed using micro-CT, HE staining and bone conversion parameters. The expression of MDA, SOD and inflammatory factors were detected to evaluate the effects of FA on oxidative stress and inflammatory response in the HFD-fed mice. Quantitative real-time PCR and Western blot (WB) were used to investigate the AMPK signaling pathway. Results: After the intervention of FA, the body fat rate of obese mice was reduced, and related metabolic disorders such as insulin resistance, hyperlipidemia, and systemic inflammation were alleviated. In correlation with those modifications, FA attenuated bone loss and improved bone microarchitecture, accompanied the number of osteoclasts and adipocytes decreased. Furthermore, FA promoted the phosphorylation of AMPK, thereby promoting the expression of Carnitine palmitoyltransferase 1 (CPT1), nuclear factor erythroid-2 related factor 2 (Nrf2) and antioxidant enzymes. Conclusion: These findings suggest that FA may modulate lipid metabolism and oxidative stress responses activating the AMPK signaling pathway, thereby alleviating HFD-induced osteoporosis. The results from our study provide experimental evidence to prevent HFD-induced osteoporosis.

The effect of BMI on the mid-term clinical outcomes of mobile-bearing unicompartmental knee arthroplasty

Objective

To evaluate the impact of body mass index (BMI) on the mid-term clinical outcomes and survival in patients receiving a mobile-bearing unicompartmental knee arthroplasty (UKA).

Methods

We retrospectively collected data from 355 patients who underwent UKA from June 2006 to June 2015, with a mean follow-up of 106.5 ± 22.5 months. Patients were assigned into four groups based on their BMI before surgery: normal weight group (BMI 18.5 ~ 22.9 kg/m²), overweight group (23 ~ 24.9 kg/m²), obesity group (25 ~ 29.9 kg/m²), and severe obesity group (≥ 30 kg/m²). The knee society score (KSS), knee society function score (KSFS), hospital for special surgery score (HSS), and range of motion (ROM) were assessed before the operation and at the last follow-up. The femorotibial angle (FTA) was assessed after the operation immediately and at the last follow-up. Kaplan–Meier survival analysis was performed among the four groups.

Results

The KSS, KSFS, and HSS in all groups were markedly improved compared with the preoperative values (p<0.001), but the ROM score was not significantly different (p>0.05). There were significant differences in KSS (p<0.001) and HSS (p = 0.004) across the four BMI groups, and these differences were due to the severe obesity group. All groups exhibited an inclination of knee varus deformity at the last follow-up (p < 0.05). Moreover, no marked difference in the implant survival rate was found among the different groups (p = 0.248), or in the survival curves (p = 0.593).

Conclusions

BMI does not influence the implant survival rate. The postoperative functional and quality-of-life scores were significantly improved in all groups. Obese (BMI ≥30 kg/m²) individuals should not be excluded from UKA.

Compatibility of Achyranthes bidentata components in reducing inflammatory response through Arachidonic acid pathway for treatment of Osteoarthritis

Achyranthes bidentate is a common traditional Chinese medicine (TCM) used in treating osteoarthritis (OA). The compatibility between effective components has now become a breakthrough in understanding the mechanism of TCM. This study aimed at determining the optimal compatibility and possible mechanism of Achyranthes bidentate for OA treatment. Results showed that the adhesion score of the OA group is higher than NC group, and showed a trend of down-regulation in the intervention group. The CHI3L1 and IL-1β in joint fluid of the OA group was significantly increased compared to the sham operation group (NC group). Group G, I, and L exhibited significantly down-regulated CHI3L1, while groups C, F, I, K, and L exhibited reduced IL-1β. Joint adhesion, damage in cartilage, and synovial tissue was found in the OA model, cartilage tissue was found recovered in groups I, J, and L, and synovial tissue was recovered in group G, I, and L. Thus, group I and L were chosen for metabolite analysis, and indole-3-propionic acid was slightly up-regulated, while koeiginequinone A, prostaglandin H2, and 1-hydroxy-3-methoxy-10-methylacridonew were down-regulated in group I and L. According to functional analysis, the arachidonic acid (AA) metabolic pathway is enriched. Down-regulated expression of vital proteins in the AA metabolism pathway, such as PGE2 and COX2 in group I and L were verified. In conclusion, Hydroxyecdysone, Oleanolic acid, Achyranthes bidentata polysaccharide at a compatibility of 0.03-μg/mg, 2.0-μg/mg, 20.0-μg/mg or 0.03-μg/mg, 2.0-μg/mg, 10.0-μg/mg, respectively, may be the optimal compatibility of Achyranthes bidentate.

Association of IFNA16 and TNFRSF19 Polymorphisms with Intramuscular Fat Content and Fatty Acid Composition in Pigs

Interferon-alpha-16 (IFNA16) and tumor necrosis factor receptor superfamily member 19 (TNFRSF19) are cytokines that may play a role in adipogenesis and fatness. Single nucleotide polymorphisms (SNPs) of the porcine IFNA16 and TNFRSF19 genes were verified and their association with intramuscular fat (IMF) content and fatty acid (FA) composition were evaluated in commercial crossbred pigs. Two non-synonymous SNPs of the porcine IFNA16 c.413G > A and TNFRSF19 c.860G > C loci were detected in commercial crossbred pigs. The porcine IFNA16 c.413G >A polymorphism was significantly associated with stearic acid, total saturated FAs (SFAs), and the ratio of monounsaturated FAs (MUFAs) to SFAs (p < 0.05). Furthermore, the porcine TNFRSF19 c.860G > C polymorphism was found to be significantly associated with IMF content and arachidic acid levels (p < 0.05). The results revealed that porcine IFNA16 and TNFRSF19 polymorphisms are related to IMF content and/or FA composition and affirmed the importance of these cytokine genes as potential candidate genes for lipid deposition and FA composition in the muscle tissue of pigs.

COVID-19 in Joint Ageing and Osteoarthritis: Current Status and Perspectives

COVID-19 is a trending topic worldwide due to its immense impact on society. Recent trends have shifted from acute effects towards the long-term morbidity of COVID-19. In this review, we hypothesize that SARS-CoV-2 contributes to age-related perturbations in endothelial and adipose tissue, which are known to characterize the early aging process. This would explain the long-lasting symptoms of SARS-CoV-2 as the result of an accelerated aging process. Connective tissues such as adipose tissue and musculoskeletal tissue are the primary sites of aging. Therefore, current literature was analyzed focusing on the musculoskeletal symptoms in COVID-19 patients. Hypovitaminosis D, increased fragility, and calcium deficiency point towards bone aging, while joint and muscle pain are typical for joint and muscle aging, respectively. These characteristics could be classified as early osteoarthritis-like phenotype. Exploration of the impact of SARS-CoV-2 and osteoarthritis on endothelial and adipose tissue, as well as neuronal function, showed similar perturbations. At a molecular level, this could be attributed to the angiotensin-converting enzyme 2 expression, renin-angiotensin system dysfunction, and inflammation. Finally, the influence of the nicotinic cholinergic system is being evaluated as a new treatment strategy. This is combined with the current knowledge of musculoskeletal aging to pave the road towards the treatment of long-term COVID-19.

Phytochemicals Mediate Autophagy Against Osteoarthritis by Maintaining Cartilage Homeostasis

Osteoarthritis (OA) is a common degenerative joint disease and is a leading cause of disability and reduced quality of life worldwide. There are currently no clinical treatments that can stop or slow down OA. Drugs have pain-relieving effects, but they do not slow down the course of OA and their long-term use can lead to serious side effects. Therefore, safe and clinically appropriate long-term treatments for OA are urgently needed. Autophagy is an intracellular protective mechanism, and targeting autophagy-related pathways has been found to prevent and treat various diseases. Attenuation of the autophagic pathway has now been found to disrupt cartilage homeostasis and plays an important role in the development of OA. Therefore, modulation of autophagic signaling pathways mediating cartilage homeostasis has been considered as a potential therapeutic option for OA. Phytochemicals are active ingredients from plants that have recently been found to reduce inflammatory factor levels in cartilage as well as attenuate chondrocyte apoptosis by modulating autophagy-related signaling pathways, which are not only widely available but also have the potential to alleviate the symptoms of OA. We reviewed preclinical studies and clinical studies of phytochemicals mediating autophagy to regulate cartilage homeostasis for the treatment of OA. The results suggest that phytochemicals derived from plant extracts can target relevant autophagic pathways as complementary and alternative agents for the treatment of OA if subjected to rigorous clinical trials and pharmacological tests.