Indoleamine 2, 3 Dioxygenase 1 Impairs Chondrogenic Differentiation of Mesenchymal Stem Cells in the Joint of Osteoarthritis Mice Model.

Osteoarthritis (OA) is a serious joint inflammation that leads to cartilage degeneration and joint dysfunction. Mesenchymal stem cells (MSCs) are used as a cell-based therapy that showed promising results in promoting cartilage repair. However, recent studies and clinical trials explored unsatisfied outcomes because of slow chondrogenic differentiation and increased calcification without clear reasons. Here, we report that the overexpression of indoleamine 2,3 dioxygenase 1 (IDO1) in the synovial fluid of OA patients impairs chondrogenic differentiation of MSCs in the joint of the OA mice model. The effect of MSCs mixed with IDO1 inhibitor on the cartilage regeneration was tested compared to MSCs mixed with IDO1 in the OA animal model. Further, the mechanism exploring the effect of IDO1 on chondrogenic differentiation was investigated. Subsequently, miRNA transcriptome sequencing was performed for MSCs cocultured with IDO1, and then TargetScan was used to verify the target of miR-122-5p in the SF-MSCs. Interestingly, we found that MSCs mixed with IDO1 inhibitor showed a significant performance to promote cartilage regeneration in the OA animal model, while MSCs mixed with IDO1 failed to stimulate cartilage regeneration. Importantly, the overexpression of IDO1 showed significant inhibition to Sox9 and Collagen type II (COL2A1) through activating the expression of ß-catenin, since inhibiting of IDO1 significantly promoted chondrogenic signaling of MSCs (Sox9, COL2A1, Aggrecan). Further, miRNA transcriptome sequencing of SF-MSCs that treated with IDO1 showed significant downregulation of miR-122-5p which perfectly targets Wnt1. The expression of Wnt1 was noticed high when IDO1 was overexpressed. In summary, our results suggest that IDO1 overexpression in the synovial fluid of OA patients impairs chondrogenic differentiation of MSCs and cartilage regeneration through downregulation of miR-122-5p that activates the Wnt1/ß-catenin pathway.

An injectable, self-healing and MMP-inhibiting hyaluronic acid gel via iron coordination.

Regulating the activity of matrix metalloproteinases (MMPs) is a potential strategy for osteoarthritis (OA) therapy, although delivering this effect in a spatially and temporally localised fashion remains a challenge. Here, we report an injectable and self-healing hydrogel enabling factor-free MMP regulation and biomechanical competence in situ. The hydrogel is realised within 1 min upon room temperature coordination between hyaluronic acid (HA) and a cell-friendly iron-glutathione complex in aqueous environment. The resultant gel displayed up to 300% in shear strain and tolerance towards ATDC 5 chondrocytes, in line with the elasticity and biocompatibility requirements for connective tissue application. Significantly enhanced inhibition of MMP-13 activity was achieved after 12 h in vitro, compared with a commercial HA injection (OSTENIL® PLUS). Noteworthy, 24-hour incubation of a clinical synovial fluid sample collected from a late-stage OA patient with the reported hydrogel was still shown to downregulate synovial fluid MMP activity (100.0 ± 17.6% ➔ 81.0 ± 7.5%), with at least comparable extent to the case of the OSTENIL® PLUS-treated SF group (100.0 ± 17.6% ➔ 92.3 ± 27.3%). These results therefore open up new possibilities in the use of HA as both mechanically-competent hydrogel as well as a mediator of MMP regulation for OA therapy.

Fluorescence Differentiation of ATP-related Multiple Enzymatic Activities in Synovial Fluid as a Marker of Calcium Pyrophosphate Deposition Disease using Kyoto Green.

Calcium pyrophosphate deposition disease (CPPD) is a crystal induced inflammation in joints, and causes severe pain in elderly people. The accumulation of pyrophosphate (PPi) in synovial fluid (SF) results from several enzymatic reactions, especially the highly activated e-NPPs, which catalyze the conversion of ATP to PPi. This study demonstrates the detection of relative catalytic activity of 3 enzymes-ecto-nucleotide pyrophosphatase/phosphodiesterases (e-NPPs), tissue nonspecific alkaline phosphatase (TNAP), and ecto-nucleoside triphosphate diphosphohydrolases (e-NTPDases)-using a single molecular sensor called Kyoto Green. Kyoto Green exhibits excellent performance in sensing the catalytic activity of the commercial representatives of the e-NPPs, TNAP, and e-NTPDases, which are ENPP1, PPase, and apyrase, respectively, in both single-enzyme and multi-enzyme assays. Analysis of SF enzymes in 19 SF samples from human and swine revealed moderate activity of e-NPPs, high activity of e-NTPDases, and low activity of TNAP. Our newly developed method for analysis of multiple enzymatic activities using Kyoto Green in biological SF will assist improvement in accuracy of the CPPD prognosis/diagnosis, which will minimize unnecessary medical procedures.

Infection Screening in Biofluids with Glucose Test Strips.

The four glucosyl esters were synthesized and tested for the determination of infection enzyme leukocyte esterase (LE) in human synovial (joint) fluid and urine. The esters acted as LE substrates releasing glucose in a direct proportion to the activity of LE in a sample. The freed glucose was then detected by a coupled-enzyme assay at either a nitrogen-doped carbon nanotube (N-CNT) electrode or a commercial glucose test strip. The assays at the N-CNT electrode detected LE down to 0.81 nM (25 µg L-1) and showed the fastest kinetics (2.1 × 105 M-1 s-1) for esters with the least crowded space around their carbonyl group. When used with glucose strips, the esters discerned clinically relevant levels of LE up to at least 26 nM (800 µg L-1) in the microliter-sized samples of bodily fluids. The reading of glucose strips with a potentiostat, instead of a personal glucose meter (blood glucometer), shortened the time of required sample incubation from 3 h to 5 min. Correcting the signal of incubated sample for that of original sample eliminated matrix effects and accounted for the presence of native glucose. The new esters have a potential to extend the use of glucose strips (already used by millions for diabetes monitoring) to the quantification of the severity of urinary tract and periprosthetic joint infections.

Determination of diagnostic value (validity) leukocyte esterase (urine dipstick strip) in differentiating inflammatory arthritis from bacterial arthritis.

BACKGROUND: The current diagnostic cornerstone for septic arthritis contains gram stains, bacterial culture, and cell count with a differential of aspirated synovial fluid. Recently, a synovial leukocyte esterase (LE) test has been used for diagnosing septic arthritis. Since this test measures the esterase activity of leukocytes, there is always a dilemma for using this test in patients with inflammatory arthritis. METHODS: We collected the synovial fluid specimens as part of the general diagnostic protocol for patients suspected of Juvenile Idiopathic Arthritis (JIA) or Septic Arthritis (SA). Each group included 34 patients. We compared the result of the synovial LE test with the result of the culture of each patient. RESULTS: The mean ages of patients were 64.14 ± 31.27 and 50.88 ± 23.19 months in the JIA group and septic arthritis group, respectively. The LE test results were positive in 30 specimens, trace in 3 and negative in one in the first-time test and were positive in 31 specimens and trace in 3 in the second-time test, while it was negative in all patients with JIA. Hence, the sensitivity of the synovial LE test was 80.8%, the specificity, PPV, and NPV were 78.6, 70.0, 86.8% respectively based on a positive culture. CONCLUSION: The leukocyte esterase strip test can be used as a rapid, bedside method for diagnosing or excluding bacterial infections in different body fluids. The synovial LE test can be used as an accurate test to rapidly rule in or out an acute articular bacterial infection, even in patients with concurrent inflammatory arthritis.

Matrix-degrading protease ADAMTS-5 cleaves inter-α-inhibitor and releases active heavy chain 2 in synovial fluids from arthritic patients.

Destruction of the cartilage matrix in joints is an important feature of arthritis. Proteolytic degradation of cartilage glycoproteins can contribute to the loss of matrix integrity. Human inter-α-inhibitor (IαI), which stabilizes the extracellular matrix, is composed of the light-chain serine proteinase inhibitor bikunin and two homologous heavy chains (HC1 and HC2) covalently linked through chondroitin 4-sulfate. Inflammation promotes the transfer of HCs from chondroitin 4-sulfate to hyaluronan by tumor necrosis factor-stimulated gene-6 protein (TSG-6). This reaction generates a covalent complex between the heavy chains and hyaluronan that can promote leukocyte invasion. This study demonstrates that both IαI and the HC-hyaluronan complex are substrates for the extracellular matrix proteases ADAMTS-5 and matrix metalloprotease (MMP) -3, -7, and -13. The major cleavage sites for all four proteases are found in the C terminus of HC2. ADAMTS-5 and MMP-7 displayed the highest activity toward HC2. ADAMTS-5 degradation products were identified in mass spectrometric analysis of 29 of 33 arthropathic patients, indicating that ADAMTS-5 cleavage occurs in synovial fluid in arthritis. After cleavage, free HC2, together with TSG-6, is able to catalyze the transfer of heavy chains to hyaluronan. The release of extracellular matrix bound HC2 is likely to increase the mobility of the HC2/TSG-6 catalytic unit and consequently increase the rate of the HC transfer reaction. Ultimately, ADAMTS-5 cleavage of HC2 could alter the physiological and mechanical properties of the extracellular matrix and contribute to the progression of arthritis.

The Leukocyte Esterase Test for Periprosthetic Joint Infection Is Not Affected by Prior Antibiotic Administration.

BACKGROUND: It has been demonstrated that administration of antibiotics prior to performing diagnostic testing for periprosthetic joint infection can interfere with the accuracy of the standard diagnostic tests. Therefore, the purpose of this study was to evaluate the effects of antibiotic administration prior to performing the synovial leukocyte esterase strip test for periprosthetic joint infection. METHODS: We identified 121 patients who underwent revision hip or knee arthroplasty for a Musculoskeletal Infection Society (MSIS)-confirmed periprosthetic joint infection. All patients also had a leukocyte esterase strip test performed. Patients in one group (32%) took antibiotics prior to the diagnostic workup, whereas patients in another group (68%) did not receive antibiotics within 2 weeks of the diagnostic workup. The leukocyte esterase strip test, erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP), synovial white blood-cell (WBC) count, and polymorphonuclear neutrophil (PMN) percentage were collected and were compared between the 2 groups. RESULTS: The median serum ESR (85 compared with 67 mm/hr for patients who did not and did receive antibiotics; p = 0.009), CRP (16.5 compared with 12.9 mg/L; p = 0.032), synovial WBC count (45,675 compared with 9,650 cells/µL; p < 0.0001), and PMN percentage (93% compared with 88%; p = 0.004) were all significantly lower for patients receiving antibiotics. Furthermore, the administration of antibiotics resulted in a significant decrease in the sensitivity of all tests, except leukocyte esterase: ESR (79.5% in the antibiotics cohort compared with 92.7% in the no-antibiotics cohort [relative risk (RR) for false-negative results, 2.8; p = 0.04]), CRP (64.2% compared with 81.8% [RR, 1.9; p = 0.03]), WBC count (69.3% compared with 93.4% [RR, 5.0; p = 0.001]), PMN percentage (74.4% compared with 91.5% [RR, 3.0; p = 0.01]), and leukocyte esterase (78% compared with 83% [RR, 1.6; p = 0.17]). The rate of negative cultures was higher in the antibiotics group at 30.7% compared with the no-antibiotics group at 12.1% (p = 0.015). CONCLUSIONS: This current study and previous studies have demonstrated that the administration of premature antibiotics can compromise the results of standard diagnostic tests for periprosthetic joint infection, causing significant increases in false-negative results. However, in this study, the leukocyte esterase strip test maintained its performance even in the setting of antibiotic administration. Antibiotic administration prior to diagnostic workups for periprosthetic joint infection stands to interfere with diagnosis. The leukocyte esterase strip test can be used as a reliable diagnostic marker for diagnosing periprosthetic joint infection even when prior antibiotics are administered. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Can leucocyte esterase replace frozen sections in the intraoperative diagnosis of prosthetic hip infection?

AIMS: Leucocyte esterase (LE) has been shown to be an accurate marker of prosthetic joint infection (PJI), and has been proposed as an alternative to frozen section (FS) histology for intraoperative diagnosis. In this study, the intraoperative assessment of LE was compared with FS histology for the diagnosis of prosthetic hip infection. PATIENTS AND METHODS: A total of 119 patients undergoing revision total hip arthroplasty (THA) between June 2015 and December 2017 were included in the study. There were 56 men and 63 women with a mean age of 66.2 years (27 to 88). Synovial fluid was collected before arthrotomy for the assessment of LE using enzymatic colourimetric strips. Between five and six samples were stained with haematoxylin and eosin for FS histology, and considered suggestive of infection when at least five polymorphonuclear leucocytes were found in five high-power fields. RESULTS: The sensitivity and specificity of the LE assay were 100% and 93.8%, respectively; the positive (PPV) and the negative (NPV) predictive values were 79.3% and 100%, respectively. The mean time between the collection of the sample and the result being known was 20.1 minutes (sd 4.4). The sensitivity and specificity of FS histology were 78.3% and 96.9%, respectively; the PPV and the NPV were 85.7% and 94.9%, respectively. The mean time between the collection of the sample and the result being known was 27.2 minutes (sd 6.9). CONCLUSION: The sensitivity of LE assay was higher, with similar specificity and diagnostic accuracy, compared with FS histology. The faster turnaround time, its ease of use, and low costs make LE assay a valuable alternative to FS histology. We now use it routinely for the intraoperative diagnosis of PJI. Cite this article: Bone Joint J 2019;101-B:372-377.

Synovial Fluid Leukocyte Esterase in the Diagnosis of Peri-Prosthetic Joint Infection: A Systematic Review and Meta-Analysis.

BACKGROUND: Peri-prosthetic joint infection (PJI) is a serious and frequent complication of total joint arthroplasty (TJA). Recently, synovial fluid leukocyte esterase (LE), measurement of which is convenient and fast, has been examined as a marker of PJI. We summarized the articles describing synovial fluid LE as a biomarker for the diagnosis of PJI and assessed its diagnostic value in patients suspected of having PJI. METHODS: We searched with appropriate key words in PubMed, Embase, Web of Science, the Cochrane database, and Science Direct. Eligible studies providing sufficient data to construct 2 × 2 contingency tables were chosen on the basis of several criteria, and the quality of the chosen studies was assessed. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated for those studies. The summary receiver operating characteristic (SROC) curve and the area under the SROC (AUSROC) were used to evaluate the overall diagnostic performance of LE. RESULTS: Eleven studies were found suitable for this systematic review. Among them, eight articles with a total of 1,011 participants qualified for meta-analysis. The pooled sensitivity, specificity, and DOR were 0.90 (95% confidence interval [CI] 0.76-0.96), 0.97 (95% CI 0.95-0.98), and 310.76 (95% CI 103.86-929.88), respectively. The SROC was 0.98 (95% CI 0.96-0.99). Sub-group analysis indicated that the sample inclusion criteria might be the main source of heterogeneity. Publication bias was suggested by an asymmetrical funnel plot (p = 0.144). CONCLUSION: Although the result of synovial fluid LE assay can be influenced by sample-related factors, it is more specific as a means to exclude PJI.

Inhibitory effect of Triperygium wilfordii polyglucoside on dipeptidyl peptidase I in vivo and in vitro.

BACKGROUD: Dipeptidyl peptidase I (DPPI), a lysosomal cysteine protease is derived from granule immune cells including mast cell, neutrophils, and toxicity T cells. DPPI can activate serine proteases by removal of dipeptides from N-termini of the pro-proteases, resulting in granule immune cells activation which involved in physiological or pathological responses. Triperygium Wilfordii Polyglucoside (TWP) is one of the traditional Chinese medicines, and commonly used in rheumatoid arthritis (RA) treatment. The present study intended to evaluate the effects of TWP on DPPI activity. METHODS: In vivo and in vitro studies were carried out to investigate the functions of TWP or triptolide (TP) on DPPI activities in serum, tissues of CIA rats. Rats were divided into five groups randomly: normal group, untreated CIA rat group, TWP treatment CIA groups (the low dose 2.5mg/100g body-weight and high dose 5mg/100g body-weight), and TP treatment CIA group (4µg/100g body-weight). Arthritis development was monitored visually, and joint pathology was examined radiologically. Total protein concentrations in synovial fluids (SFs) were determined by BCA method. Serums and tissue homogenates from CIA rats were collected and DPPI activities were detected using fluorescence substrate GF-AFC. The in vitro interactions between DPPI in serums or in tissue homogenates and TWP or TP were assessed. RESULTS: TWP-treated CIA rats showed a significant improvement in bone erosion. TWP significantly suppressed paw swelling and total protein concentration in the SFs of CIA rats compared with untreated CIA rats. The elevated activities of DPPI in serums or tissues of CIA rats were significantly inhibited by TWP, but not by TP in vivo. The inhibitory effects of TWP on DPPI activities were also confirm by in vitro study. CONCLUSION: One of the therapeutic functions of TWP in RA treatment could be inhibiting DPPI activity in serums and synovial tissue produced during RA development, and then reducing inflammatory serine proteases activities and further recovering CIA rats from RA symptoms.

Platelets Contribute to the Accumulation of Matrix Metalloproteinase Type 2 in Synovial Fluid in Osteoarthritis.

Inflammation plays a role in the initiation and progression of osteoarthritis (OA), a chronic degenerative joint disorder. Platelets are inflammatory cells, contain and release matrix metalloproteinases (MMPs) and favour the release of these enzymes, key effectors of cartilage and subchondral bone degradation, by other cells; however, their role in OA has not been investigated yet. Our aims were (1) to assess the presence of platelets and of MMP-2 in synovial fluid (SF) of OA patients; (2) to evaluate the contribution of platelets to MMP-2 release by fibroblast-like synoviocytes (FLS); and (3) to investigate if hyaluronic acid (HA) interferes with these processes. SF was collected from 27 OA patients before and after treatment with intra-articular HA (20 mg/2 mL). Moreover, FLS were co-cultured with platelets, and the release of MMP-2 in supernatants was measured. Our results show that platelets are present in OA SF and show markers of activation. OA SF also contains relevant amounts of MMP-2. Co-incubation of platelets with FLS favours the release of MMP-2 by the interaction of platelet surface P-selectin with FLS CD44 by a mechanism involving the activation of pAkt and pSrc in FLS. Administration of HA to OA patients decreased the infiltration of platelets in SF and reduced the levels of MMP-2. The addition of HA in vitro inhibited the release of MMP-2 by FLS triggered by the interaction with platelets. In conclusion, our data show that platelets may contribute to joint degeneration in OA by favouring the accumulation of MMP-2 in SF.

The regulatory role of Dipeptidyl peptidase I on the activation of immune granulocytes.

Dipeptidyl peptidase I (DPPI), a lysosomal cysteine protease, required for activation of serine proteases of granulocytes including mast cells (MCs), neutrophils (NPs) and others, which were found in synovial tissue of patients with rheumatoid arthritis (RA). But, the role of DPPI associated with those cells in RA development is unclear. In this study, the collagen-induced-arthritis (CIA) rat-model was employed to investigate the expression and activity levels of DPPI and its association with RA progress. Primary granulocytes were freshly extracted from bone-marrows of normal or CIA rats, human mast cell line LAD-2 and primary neutrophils, human-recombinant-DPPI, DPPI-inhibitor Gly-Phe-CHN2 , LTB4, anti-IgE antibody, calcium ionophore were used to study the regulatory role of DPPI in cell activations. The increased DPPI activities in synovial fluids, serum, and bone-marrow homogenates of CIA rats associated with RA severities progress were observed after injections. MMP2/9 expressions in SFs and bone-marrow were in different patterns. Regular-Blood-Tests have shown the high leveled DPPI activities associated with granulocytes differentiations in-vivo in blood of CIA rats. In-vitro cell models, DPPI up-regulated the proliferation of primary bone-marrow granulocytes of normal rats, but inhibited that of CIA rats. DPPI up-regulated and Gly-Phe-CHN2 down-regulated MCs intracellular DPPI and chymase activities. Gly-Phe-CHN2 also inhibited the LTB4 -activated-NPs and NP-elastase activities. Following stimulation of calcium ionophore, the net-releases of DPPI and ß-hexosaminidase from MCs were increased over a time-course, while Gly-Phe-CHN2 down-regulated MCs and NPs activation. Our findings demonstrate the role of DPPI in regulating MCs and NPs activation, and modulating proteolysis in the process of RA.

Effect of Depth of Centrifuged Synovial Fluid on Leukocyte Esterase Test for Periprosthetic Joint Infection.

Centrifugation of aspirated synovial fluid before leukocytes esterase (LE) testing for diagnosing periprosthetic joint infection (PJI) may make blood tinged specimens interpretable. We aimed to establish the proper sampling depth of centrifuged specimens for LE testing as one diagnostic criterion and also AS-D chloroacetate esterase (CAE) staining testing as an adjunctive tool. A definite PJI knee joint group and an aseptic primary total knee arthroplasty control group were studied quasi-experimentally (N = 46). At 2,000 g for 15 min, 3 ml of synovial fluid was centrifuged. LE strip testing and median synovial WBC count were performed at 2, 4, and 6 mm depths. CAE staining test characterized LE particles. ROC curve, area under the curve, and significant differences were determined. The proper predictive depth to diagnose PJI was sought by forward stepwise logistic regression. All fresh blood-tinged specimens had uncertain interpretations. Centrifugation increased interpretability (55-100%). ROC curve and area under the curve at 2, 4, and 6 mm depths were 0.822, 0.804, and 0.786, respectively. The cut point of ++ to diagnose PJI was statistically significant (p < 0.05) at all depths. p-values of forward stepwise logistic regression at 2, 4, and 6 mm were 0.001, 0.752, and 0.756, respectively. CAE staining confirmed extracellular LE release by polymorphonuclear neutrophils (PMN). A specimen at <2 mm from the surface of centrifuged synovial fluid at a grading of ++ or more for PJI diagnosis is proper for LE testing. CAE staining testing adjunctively characterizes LE particles and cell morphology. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2545-2550, 2017.

Effectiveness of leucocyte esterase as a diagnostic test for acute septic arthritis.

BACKGROUND: We hypothesized that leucocyte esterase strip test can aid in diagnosing septic arthritis in native synovial fluid because leucocyte esterase concentrations would be elevated at the infection site because of secretion by recruited neutrophils. METHOD: The cohort included 27 patients (suspected septic arthritis and normal subjects). A standard chemical test strip (graded as negative, trace, +, ++ or +++) was used to detect the presence of leucocyte esterase. Fluid leucocyte count, Gram staining, culture, erythrocyte sedimentation rate and C-reactive protein were also assessed. RESULTS: The leucocyte esterase test with a threshold of ++/+++ had a sensitivity of 79.2% (95% CI [confidence interval], 65.9% to 89.2%), specificity of 80.8% (95% CI, 73.3% to 87.1%), positive predictive value (PPV) of 61.8% (95% CI, 49.2% to 73.3%) and negative predictive value (NPV) of 90.1% (95% CI, 84.3% to 95.4%). CONCLUSION: The leucocyte esterase strip test yielded a high specificity, PPV, NPV, high sensitivity and high diagnostic accuracy. Leucocyte esterase is an accurate, quick and bedside test for septic arthritis and can be used effectively for diagnosing periprosthetic joint infections along with other battery of tests according to the Musculoskeletal Infection Society criteria.

The role of molecular pain biomarkers in temporomandibular joint internal derangement.

There is evidence that low-grade inflammation may be responsible for pain and development of degenerative changes in temporomandibular joint internal derangement. This article reviews the current knowledge of the molecular mechanisms behind TMJ internal derangements. A non-systematic search was carried out in PubMed, Embase and the Cochrane library for studies regarding pathophysiological mechanisms behind internal derangements focusing on pain-mediating inflammatory and cartilage-degrading molecules. Recent data suggest that release of cytokines may be the key event for pain and cartilage destruction in TMJ internal derangements. Cytokines promote the release of matrix metalloproteinases (MMPs), and due to hypoxia, vascular endothelial growth factor (VEGF) is released. This activates chondrocytes to produce MMPs and reduce their tissue inhibitors (TIMPs) as well as the recruitment of osteoclasts, ultimately leading to cartilage and bone resorption. Also, proteoglycans have an important role in this process. Several cytokines, MMPs, TIMPs and VEGF have been identified in higher concentrations in the TMJ synovial fluid of patients with painful internal derangements and shown to be associated with the degree of degeneration. Other molecules that show elevated levels include hyaluronic acid synthase, disintegrin and metalloproteinase with thrombospondin motifs (ADAMTs), aggrecan, fibromodulin, biglycan and lumican. Taken together, more or less pronounced inflammation of TMJ structures with release of cytokines, MMPs and other molecular markers that interact in a complex manner may be responsible for tissue degeneration in internal derangements. As internal derangements may be symptom-free, the degree of inflammation, but also other mechanisms, may be important for pain development.

[Age-related traits of cytogenetic abnormalities in synovial cells of knee-joint in residents of the North of Siberia with arthritis of different etiology depending on the GSTM1 gene polymorphism of glutathion-S-transferase.]

It was studied the frequency of cells with cytogenetic abnormalities in the synovial fluid cells of the knee joint in patients of different age groups suffering from chronic arthritis associated with Lyme borreliosis (CAALB) or post-traumatic arthritis (PTA), depending on the polymorphism of the GSTM1 gene of glutathione-S-transferase. The study included 135 residents of the north of the Tomsk and Tyumen regions, 68 of whom suffered from CAALB, and the rest of the 67 patients who made up the control group were diagnosed with PTA. The results of this study have demonstrated that there are significant age-related differences in the frequency of cytogenetic abnormalities of the synovial fluid cells of the knee joint between young and elderly patients of СAALB. The integrative assessment of clinical and cytogenetic parameters in the group of elderly СAALB patients with mutant GSTM1 (0/0) allele, as compared with the other groups, enable to conclude that there are significant positive correlations between the indices of the severity disruption of articular locomotor function and the frequency of synovial fluid cells with trisomy of chromosome 7.

[Correlation of DNase I in serum and synovial fluid with inflammatory activity in patients with rheumatoid arthritis].

OBJECTIVE: To investigate the potential role of deoxyribonuclease I (DNase I) in the pathogenesis of rheumatoid arthritis (RA). METHODS: DNase I activity was measured by radial enzyme-diffusion method in serum samples from 83 RA patients and 60 healthy volunteers and in the synovial fluid (SF) from 27 RA patients and 38 patients with other inflammatory arthritis. SF cfDNA level was measured with Pico Green Kit, and the correlation among DNase I activity, cfDNA level and clinical parameters of RA patients was analyzed. RESULTS: Serum DNase I activity was significantly lower in RA patients than in the healthy control subjects (0.3065∓0.1436 vs 0.4289∓0.1976 U/mL, P<0.001), and was negatively correlated with ESR (r=-0.2862, P=0.0122), CRP (r=-0.2790, P=0.0184) and neutrophil cell counts (r=-0.287, P=0.011). SF DNase I activity was almost negative in patients with RA, ankylosing spondylitis (AS) and gouty arthritis (GA). SF cfDNA level in RA patients was significantly higher than that in patients with osteoarthritis (100.81∓142.98 vs 18.98∓31.40 µg/mL, P=0.002), but similar to that in patients with AS (45.85∓47.67 µg/mL, P=0.428) and GA (162.95∓97.49 µg/mL, P=0.132). In patients with inflammatory arthritis, SF cfDNA level was positively correlated with ESR (r=0.4106, P=0.0116) and CRP (r=0.5747, P=0.0002). CONCLUSION: Impairment of DNase I activity may be responsible for the enhanced NETs generation and plays a role in the pathogenesis of RA.

Copper-Mediated DNA-Scaffolded Silver Nanocluster On-Off Switch for Detection of Pyrophosphate and Alkaline Phosphatase.

We present a new copper-mediated on-off switch for detecting either pyrophosphate (PPi) or alkaline phosphatase (ALP) based on DNA-scaffolded silver nanoclusters (DNA/AgNCs) templated by a single-stranded sequence containing a 15-nt polythymine spacer between two different emitters. The switch is based on three favorable properties: the quenching ability of Cu(2+) for DNA/AgNCs with excitation at 550 nm; the strong binding capacity of Cu(2+) and PPi; and the ability of ALP to transform PPi into orthophosphate (Pi). The change in fluorescence of DNA/AgNCs depends on the concentrations of Cu(2+), PPi, and ALP. Copper(II) acts as a mediator to interact specifically with the Probe, while PPi and ALP convert the signal of the Probe by removing and recovering Cu(2+), operating as an on-off switch. In the presence of Cu(2+) only, DNA/AgNCs exhibit low fluorescence because the combination of Cu(2+) and DNA template disturbs the precise formation of DNA/AgNCs. When PPi is added to the system containing Cu(2+), free DNA template is obtained due to the stronger interaction of PPi and Cu(2+), leading to a significant fluorescence increase (ON state) which depends on the concentration of PPi. Further addition of ALP results in the release of free Cu(2+) via ALP-catalysis of hydrolysis of PPi into Pi, thereby returning the system to the low fluorescence OFF state. The switch allows the analysis of either PPi or ALP by observation of the fluorescence status, with the detection limit of 112.69 nM and 0.005 U/mL for PPi and ALP, respectively. The AgNCs on-off switch provides the advantages of simple design, convenient operation, and low experimental cost without need of chemical modification, organic dyes, or separation procedures.

Synovial fluid matrix metalloproteinase-2 and -9 activities in dogs suffering from joint disorders.

The activity of matrix metalloproteinase (MMP)-2 and MMP-9 in synovial fluids (SF) sampled from dogs with joint disorders was investigated by gelatin zymography and densitometry. Pro-MMP-2 showed similar activity levels in dogs with idiopathic polyarthritis (IPA; n=17) or canine rheumatoid arthritis (cRA; n=4), and healthy controls (n=10). However, dogs with cranial cruciate ligament rupture (CCLR; n=5) presented significantly higher pro-MMP-2 activity than IPA and healthy dogs. Meanwhile, dogs with IPA exhibited significantly higher activity of pro- and active MMP-9 than other groups. Activity levels in pro- and active MMP-9 in cRA and CCLR dogs were not significantly different from those in healthy controls. Different patterns of MMP-2 and MMP-9 activity may reflect the differences in the underlying pathological processes.

Plasma and Synovial Fluid TrxR Levels are Correlated With Disease Risk and Severity in Patients With Rheumatoid Arthritis.

This study was designed and performed to establish the relationship between plasma and synovial fluid (SF) levels of thioredoxin reductase (TrxR) and disease activity in Chinese patients with rheumatoid arthritis (RA).This study consisted of a total of 224 patients diagnosed with RA, 224 age and sex-matched healthy controls, and 156 patient controls. The disease activity of RA patients was calculated as diseases activity score that include 28-joint counts (DAS 28), which was divided into low-diseases activity (LDA) and high-diseases activity (HDA) groups.Increased plasma TrxR was detected in patients with RA than healthy controls (P < 0.0001). With an area under the curve (AUC) of 0.874, plasma TrxR showed a evidently greater discriminatory ability than C-reactive protein (CRP; AUC, 0.815), antistreptolysin-O (ASO; AUC, 0.631), rheumatoid factor (RF, AUC, 0.793), and erythrocyte sedimentation rate (ESR, AUC, 0.789) in diagnosing RA. RA patients with HDA had significantly elevated TrxR levels in plasma and SF than did those with LDA (P < 0.0001). With an AUC of 0.874, plasma TrxR levels as an indicator for screening of HDA showed a significantly greater discriminatory ability than CRP (AUC, 0.690), ASO (AUC, 0.597), RF (AUC, 0.657), and ESR (AUC, 0.603). Similarly, SF TrxR levels as an indicator for screening of HDA also showed a significantly greater discriminatory ability as compared with above biomarkers.TrxR levels in plasma and SF were positively correlated with the severity of RA. TrxR levels may therefore serve as a new biomarker in addition of the traditional biomarkers for assessing the risk and severity of RA. Further analysis of TrxR release machinery may give us a new understanding of pathogenesis of RA.