OBJECTIVE: To analyze the differences in the effects of different mechanical stimuli on cells, cytokines, and proteins in synovial fluid of osteoarthritis joints, and to elucidate the indirect mechanism by which mechanical signals remodel the synovial fluid microenvironment through tissue cells. METHODS: Systematically integrate recent literature, focusing on the regulatory effects of different mechanical stimuli on the physicochemical properties of synovial fluid. Analyze the dynamic process by which mechanical stimuli regulate secretory and metabolic activities through tissue cells, thereby altering the physicochemical properties of cytokines and proteins. RESULTS: Appropriate mechanical stimuli activate mechanical signals in chondrocytes, macrophages, and synovial cells, thereby influencing cellular metabolic activities, including inhibiting the release of pro-inflammatory factors and promoting the secretion of anti-inflammatory factors, and regulating the expression of matrix and inflammation-related proteins such as cartilage oligomeric matrix protein, peptidoglycan recognition protein 4, and matrix metalloproteinases. CONCLUSION Mechanical stimuli act on tissue cells, indirectly reshaping the synovial fluid microenvironment through metabolic activities, thereby regulating the pathological process of osteoarthritis.
Humans ; Osteoarthritis/physiopathology* ; Synovial Fluid/chemistry* ; Chondrocytes/metabolism* ; Cytokines/metabolism* ; Macrophages/metabolism* ; Stress, Mechanical ; Cartilage Oligomeric Matrix Protein/metabolism* ; Matrix Metalloproteinases/metabolism* ; Synovial Membrane/cytology*

OBJECTIVE: To reveal the molecular basis of knee osteoarthritis (KOA) with Yang deficiency and blood stasis syndrome by analyzing the gene expression profiles in synovial fluid and blood of KOA patients with this syndrome. METHODS: A total of 80 KOA patients were recruited from October 2022 to June 2024, including 40 cases in the non-Yang deficiency and blood stasis group (27 males and 13 females), with an average age of (61.75±3.45) years old;and 40 cases in the Yang deficiency and blood stasis group (22 males and 18 females), with an average age of (62.00±2.76) years old. The levels of body mass index (BMI), high-density lipoprotein (HDL), low-density lipoprotein (LDL), fibrinogen, total cholesterol, and D-dimer were recorded and summarized. Blood and synovial fluid samples from patients were collected for gene expression profile microarray sequencing, and then PCR and immunohistochemistry were used for clinical verification on the patients' synovial fluid and cartilage samples. RESULTS: Logistic regression analysis showed that compared with KOA patients with non-Yang deficiency and blood stasis syndrome, those with Yang deficiency and blood stasis syndrome had increased BMI, LDL, fibrinogen, total cholesterol, and D-dimer, and decreased HDL, with a clear correlation between the two groups. There were 562 differential genes in the blood, among which 322 were up-regulated and 240 were down-regulated;755 differential genes were found in the synovial fluid, with 350 up-regulated and 405 down-regulated. KEGG signaling pathway analysis of synovial fluid revealed changes in lipid metabolism-related pathways, including cholesterol metabolism, fatty acid metabolism, and PPARG signaling pathway. Analysis of the involved differential genes identified 6 genes in synovial fluid that were closely related to lipid metabolism, namely LRP1, LPL, ACOT6, TM6SF2, DGKK, and PPARG. Subsequently, PCR and immunohistochemical verification were performed using synovial fluid and cartilage samples, and the results were consistent with those of microarray sequencing. CONCLUSION This study explores the clinical and genomic correlation between traditional Chinese medicine syndromes and knee osteoarthritis from the perspective of lipid metabolism, and proves that abnormal lipid metabolism is closely related to KOA with Yang deficiency and blood stasis syndrome from both clinical and basic aspects.
Humans ; Male ; Female ; Middle Aged ; Synovial Fluid/metabolism* ; Osteoarthritis, Knee/metabolism* ; Yang Deficiency/complications* ; Aged

Objective Based on 25 indicators including immune factors, cell count classification, and smear results of the knee joint fluid, machine learning models were established to distinguish between osteoarthritis (OA) and rheumatoid arthritis (RA). Methods 100 OA and 40 RA patients scheduled for total knee arthroplasty were enrolled respectively. Each patient's knee joint fluid was collected preoperatively. Nucleated cells were counted and classified. The expression levels of immune factors, including tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, IL-8, IL-15, matrix metalloproteinase 3 (MMP3), MMP9, MMP13, rheumatoid factor (RF), serum amyloid A (SAA), C-reactive protein (CRP), and others were measured. Smears and microscopic classification of all the immune factors were performed. Independent influencing factors for OA or RA were identified using univariate binary logistic regression, Lasso regression, and multivariate binary logistic regression. Based on the independent influencing factors, three machine learning models were constructed which are logistic regression, random forest, and support vector machine. Receiver operating characteristic curve (ROC), calibration curve and decision curve analysis (DCA) were used to evaluate and compare the models. Results A total of 5 indicators in the knee joint fluid were screened out to distinguish OA and RA, which were IL-1β(odds ratio(OR)=10.512, 95× confidence interval (95×CI) was 1.048-105.42, P=0.045), IL-6 (OR=1.007, 95×CI was 1.001-1.014, P=0.022), MMP9 (OR=3.202, 95×CI was 1.235-8.305, P=0.017), MMP13 (OR=1.002, 95× CI was 1-1.004, P=0.049), and RF (OR=1.091, 95×CI was 1.01-1.179, P=0.026). According to the results of ROC, calibration curve and DCA, the accuracy (0.979), sensitivity (0.98) and area under the curve (AUC, 0.996, 95×CI was 0.991-1) of the random forest model were the highest. It has good validity and feasibility, and its distinguishing ability is better than the other two models. Conclusion The machine learning model based on immune factors in the knee joint fluid holds significant value in distinguishing OA and RA. It provides an important reference for the clinical early differential diagnosis, prevention and treatment of OA and RA.
Humans ; Arthritis, Rheumatoid/metabolism* ; Machine Learning ; Male ; Female ; Middle Aged ; Aged ; Synovial Fluid/immunology* ; Osteoarthritis, Knee/metabolism* ; Knee Joint/metabolism* ; ROC Curve ; Diagnosis, Differential

OBJECTIVE: To examine the expression of chemokine receptor CCR10 on monocytes/macrophages in the joints of patients with rheumatoid arthritis (RA), and to investigate the role of chemokine CCL28 and its receptor CCR10 in the migration of RA monocytes and its mechanism. METHODS: The expression of CCR10 in synovial tissues from 8 RA patients, 4 osteoarthritis (OA) patients, and 4 normal controls was analyzed by immunohistochemistry, and cell staining was scored on a 0-5 scales. Flow cytometry was used to measure the percentage of CCR10 positive cells in CD14⁺ monocytes from peripheral blood of 26 RA patients and 20 healthy controls, as well as from synovial fluid of 15 RA patients. The chemotactic migration of monocytes from RA patients and healthy controls in response to CCL28 was evaluated using an in vitro Transwell system. Western blotting was conducted to assess phosphorylation of the extracellular signal-regulated kinase (ERK) and protein kinase B (Akt) pathways in RA monocytes upon CCL28 treatment. RESULTS: CCR10 was predominantly expressed in RA synovial lining cells and sublining macrophages, endothelial cells, and lymphocytes. CCR10 expression was significantly increased on lining cells and sublining macrophages in RA synovial tissue compared with OA and normal synovial tissue (both P < 0.01). The patients with RA had markedly elevated expression of CCR10 on peripheral blood CD14⁺ monocytes compared with the healthy controls [(15.6±3.0)% vs. (7.7±3.8)%, P < 0.01]. CCR10 expression on synovial fluid monocytes from the RA patients was (32.0±15.0)%, which was significantly higher than that on RA peripheral blood monocytes (P < 0.01). In vitro, CCL28 caused significant migration of CD14⁺ monocytes from peripheral blood of the RA patients and the healthy controls at concentrations ranging from 10-100 μg/L (all P < 0.01). The presence of neutralizing antibody to CCR10 greatly suppressed CCL28-driven chemotaxis of RA monocytes (P < 0.01). Stimulation of RA monocytes with CCL28 induced a remarkable increase in phosphorylation of ERK and Akt (both P < 0.05). ERK inhibitor (U0126) and phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002) strongly reduced the migration of RA monocytes in response to CCL28 (both P < 0.01). CONCLUSION RA patients had increased CCR10 expression on peripheral blood, synovial fluid, and synovial tissue monocytes/macrophages. CCL28 ligation to CCR10 promoted RA monocyte migration through activation of the ERK and PI3K/Akt signaling pathways. The CCL28-CCR10 pathway could participate in monocyte recruitment into RA joints, thereby contributing to synovial inflammation and bone destruction.
Humans ; Monocytes/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Endothelial Cells/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Arthritis, Rheumatoid ; Synovial Membrane ; Chemokines, CC/metabolism* ; Synovial Fluid ; Osteoarthritis ; Receptors, CCR10/metabolism*

OBJECTIVETo compare and estimate the diagnostic value and characteristic of different diagnostic methods (blood laboratory test, histological analysis, synovial fluid cytological test and microbiological examination) in detecting the presence of periprosthetic joint infection.

METHODSData of 52 patients underwent hip or knee joint revision in Peking University People's Hospital Arthritis Clinic and Research Center between July 2013 and March 2015 were analyzed retrospectively. For each patient, results of blood laboratory tests(peripheral-blood white blood cell, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6) and high-sensitivity C-reactive protein (Hs-CRP)), histological analysis, synovial fluid white cell count (SWCC), microbiological examinations (synovial fluid, tissue and prosthetic joint sonication fluid) were collected. Data were analyzed by t-test, independent sample median test or χ(2) test, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy for each method were calculated and compared by receiver operating characteristic curve.

RESULTSThere were 30 female and 22 male patients. Twenty-one patients (40.4%) were diagnosed as PJI. The levels of CRP, ESR, IL-6 and Hs-CRP in patients with PJI were higher than that in aseptic failure patients (Z=23.084, 13.499, 5.796, 17.045, all P<0.05). The sensitivities of CRP, ESR, IL-6 and Hs-CRP were 90.5%, 81.0%, 95.0% and 90.0%. The sensitivities of histological analysis and SWCC were 55.0% and 70.6%, while they had high specificity as 89.7% and 85.7%. The sensitivity of sonication fluid culture was 90.0%, which was higher than that of tissue culture (71.4%) and synovial fluid culture (65.0%) (χ(2) = 5.333, 6.400, all P<0.05).

CONCLUSIONSThe tests of CRP, ESR, IL-6 and Hs-CRP have good value in detecting PJI preoperatively. Histological analysis and SWCC have high specificity, which could help to exclude PJI. Sonication fluid culture has a higher sensitivity than tissue culture and synovial fluid culture.

Arthroplasty, Replacement, Hip ; Arthroplasty, Replacement, Knee ; Blood Sedimentation ; C-Reactive Protein ; metabolism ; Female ; Humans ; Interleukin-6 ; blood ; Knee Joint ; Male ; Prosthesis-Related Infections ; diagnosis ; ROC Curve ; Retrospective Studies ; Sensitivity and Specificity ; Synovial Fluid ; cytology

Chemokine-like factor 1 (CKLF1) is a newly cloned chemotactic cytokine with CCR4 being its functional receptor. Recent evidence demonstrates a role of CKLF1 in arthritis. The aim of this study was to quantify the expression of CKLF1 as well as assess the correlation between CKLF1 and plasma acute-phase markers. Synovium was obtained from 16 osteoarthritis (OA), 15 rheumatoid arthritis (RA) and 10 ankylosing spondylitis (AS) patients undergoing total joint arthroplasty, with other 11 patients treated for meniscal tears during sport accidents serving as normal controls. Levels of CKLF1 and CCR4 mRNA were detected by qRT-PCR, and the expression of CKLF1 was investigated by immunohistochemistry staining, subsequently analyzed with semiquantitative scores. Plasma acute-phase markers of inflammation were determined by ELISA. CKLF1 was found with a particularly up-regulated expression in synovim from AS and RA patients, and CCR4 mRNA levels increased in RA patients, not in OA or AS patients. Elevated levels of plasma markers of inflammation including CRP, ESR and D-dimer were observed in RA. Further, significantly positive correlations between relative expression levels of CKLF1 and CRP/ESR in RA patients and a positive correlation between CKLF1 and ESR in AS patients were found. There was no detectable correlation between CKLF1 and plasma D-dimer. This study confirms an increased but different level of CKLF1 in RA, OA and AS patients, all significantly higher than that in controls. Additionally, the significant positive correlations between CKLF1 levels and CRP/ESR in RA and between CKLF1 and ESR suggest that CKLF1 might contribute to the inflammation state and clinical symptoms in these rheumatic diseases. Further studies are required to investigate the utility of targeting specific CKLF1 for symptom control or disease modification in RA and AS.
Adult ; Arthritis, Rheumatoid ; metabolism ; Biomarkers ; metabolism ; Case-Control Studies ; Chemokines ; genetics ; metabolism ; Female ; Humans ; MARVEL Domain-Containing Proteins ; genetics ; metabolism ; Male ; Middle Aged ; Osteoarthritis ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Receptors, CCR4 ; genetics ; metabolism ; Spondylitis, Ankylosing ; metabolism ; Synovial Fluid ; metabolism

BACKGROUNDPeriprosthetic joint infection (PJI) is the main cause of failure following total joint arthroplasty. Until now, the diagnosis of PJI is still confronted with technical limitations, and the question of whether synovial fluid biomarker, C-reactive protein (CRP), can provide high value in the diagnosis of PJI remains unanswered and, therefore, was the aim of the study.

METHODSFirst, we conducted a systematic review on CRP in the diagnosis of PJI by searching online databases using keywords such as "periprosthetic joint infection", "synovial fluid", and "C-reactive protein". Eligible studies providing sufficient data to construct 2 × 2 contingency tables were then selected based on the list of criteria and the quality of included studies was assessed subsequently. Finally, the reported sensitivity, specificity, diagnostic odds ratio (DOR), summary receiver operating characteristic (SROC) curve, and the area under the SROC (AUSROC) were pooled together and used to evaluate overall diagnostic performance.

RESULTSSeven studies were included in our review, six of which comprising a total of 456 participants were further investigated in our meta-analysis. The pooled sensitivity, specificity, and DOR were 0.92 (95% confidence interval [CI]: 0.86-0.96), 0.90 (95% CI: 0.87-0.93), and 101.40 (95% CI: 48.07-213.93), respectively. The AUSROC was 0.9663 (standard error, 0.0113).

CONCLUSIONSSynovial fluid CRP is a good biomarker for the diagnosis of PJI with high sensitivity and specificity.

Arthroplasty, Replacement, Hip ; adverse effects ; Arthroplasty, Replacement, Knee ; adverse effects ; Biomarkers ; metabolism ; C-Reactive Protein ; metabolism ; Female ; Humans ; Male ; Prosthesis-Related Infections ; diagnosis ; Synovial Fluid ; metabolism

Objective To investigate the expression of miRNA-140 in chondrocytes and synovial fluid of osteoarthritis (OA) patients, and explore the relationship between the miRNA-140 expression and OA severity.Methods This study enrolled 30 OA patients who underwent total knee arthroplasty for chondrocytes sampling and 30 OA patients who underwent intra-articular injection for synovial fluid sampling. All OA patients were grouped into mild [Kellgren and Lawrence (KL) grade 1-2], moderate (KL grade 3) and severe (KL grade 4), with 10 in each subgroups for each sampling purposes. 7 non-OA patients and 10 patients with knee injury were collected for cartilage and synovial fluid sampling respectively as control groups. Chondrocytes were isolated from the cartilage tissue and cultured in vitro. Quantitative real time PCR for miRNA-140 in chondrocytes and synovial fluid were performed, and the U6 snRNA was used as internal control. The expression difference of miRNA-140 among groups and correlation between the expression and the KL grade of OA were analysed using one-way ANOVA and Spearman test respectively. Results The expression of miRNA-140 in chondrocytes of knees in OA patients was reduced than that in normal knees, and the between-group difference was statistically significant (F=305.464, P<0.001). miRNA-140 could be detected in synovial fluid of both normal knees and OA knees, its relative expression level was reduced in synovial fluid of OA group compared with normal group, and the between-group difference was statistically significant as well (F=314.245, P<0.001). The relative expression level of miRNA-140 in both chondrocytes and synovial fluid were negatively correlated with the KL grade of OA(r=-0.969, P<0.001; r=-0.970, P<0.001). Conclusion miRNA-140 could be detected in chondrocytes and synovial fluid of OA patients, and its expression was negatively correlated with the severity of OA.
Adult ; Aged ; Cells, Cultured ; Chondrocytes ; metabolism ; Female ; Humans ; Knee Joint ; metabolism ; Male ; MicroRNAs ; analysis ; Middle Aged ; Osteoarthritis, Knee ; metabolism ; Real-Time Polymerase Chain Reaction ; Synovial Fluid ; metabolism

OBJECTIVETo explore the effect of Bushen Gujin Recipe (BGR) on serum and synovial expression of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-α) in knee osteoarthritis (KOA) model rabbits.

METHODSTotally 36 8-month-old healthy male New Zealand white rabbits were randomly divided into 4 groups, i.e., the normal control group, the model group, the Western medicine group (Meloxicam, at the daily dose of 6 mg/kg), and the TCM group (BGR, at the daily dose of 53 g/kg), 9 in each group. Modeling was performed in all rabbits except those in the normal control group by using Hulth A method. All medication was performed for 8 consecutive weeks. Contents of IL-1 and TNF-α were detected using ELISA from serum, partial synovial tissue of the front knee joint, cartilage and subchondral bone of the medial femoral condyle.

RESULTSThe joint space became narrowed in the Western medicine group, ranging between the model group and the TCM group. The articular surface was rough with obvious osteophytes. The joint space was slightly narrower in the TCM group; the articular surface was slightly rough with mild osteophytes. Compared with the normal control group, contents of IL-1 and TNF-α in serum and synovial increased in the model group (P < 0.01). Compared with the model group, contents of IL-1 and TNF-α in serum and the synovial fluid decreased in the two treatment groups (P < 0.01). There was no statistical difference in contents of IL-1 and TNF-α between the Western medicine group and the TCM group.

CONCLUSIONBGR promoted the synthesis of cartilage matrix and carti- lage repair through inhibiting the secretion of IL-1 and TNF-α, and prolonging cartilage degeneration.

Animals ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Interleukin-1 ; metabolism ; Knee Joint ; Male ; Osteoarthritis, Knee ; drug therapy ; metabolism ; Rabbits ; Synovial Fluid ; Synovial Membrane ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo probe the function of interleukin-17 (IL-17) in rheumatoid arthritis (RA) patients of accumulated dampness-heat obstruction in joints syndrome (ADOJS) by detecting levels of IL-17 in serum and the synovial fluid and analyzing its correlation with erythrocyte sedimentation rate (ESR) and C reactive protein (CRP).

METHODSFrom January 2011 to January 2013, recruited were 90 RA inpatients of ADOJS at Department of Integrative Medical Rheumatism, General Hospital of Chengdu Military Region, of which 28 patients had knee joint effusion. Besides, 30 healthy volunteers who received physical examination at our hospital were recruited as the normal control group, and 30 patients with osteoarthritis (OA) who had knee joint effusion were recruited as the synovial fluid control group. The expression levels of IL-17 in serum and the synovial fluid were detected by enzyme linked immunosorbent assay (ELISA), and contents of ESR and CRP were detected in RA patients. Then correlation analyses were performed between levels of IL-17 and contents of ESR and CRP.

RESULTSCompared with the normal serum control group, the expression levels of IL-17 in serum of RA patients significantly increased (P < 0.05). Compared with the serum of RA patients and the synovial fluid of OA patients, the expression levels of IL-17 in the synovial fluid of RA patients significantly increased (P < 0.05). The expression levels of IL-17 in serum of RA patients were not correlated with ESR or CRP (r = 0.092, -0.082; P > 0.05), and the expressional levels of IL-17 in the synovial fluid of RA patients were not correlated with ESR or CRP (r = 0.113, -0.034; P > 0.05).

CONCLUSIONSIL-17 was the main effector cytokine of Th17 cells. The expressional levels of IL-17 significantly increased in serum and the synovial fluid of RA patients of ADOJS, but with no correlation to ESR or CRP. It indicated that IL-17 participated in the occurrence and development of RA. Concrete mechanisms needed to be further proved in larger samples.

Aged ; Arthritis, Rheumatoid ; blood ; diagnosis ; metabolism ; Blood Sedimentation ; C-Reactive Protein ; metabolism ; Case-Control Studies ; Female ; Humans ; Interleukin-17 ; blood ; metabolism ; Male ; Medicine, Chinese Traditional ; Middle Aged ; Synovial Fluid ; metabolism