Hemoglobin stimulates the expression of ADAMTS-5 and ADAMTS-9 by synovial cells: a possible cause of articular cartilage damage after intra-articular hemorrhage.

BACKGROUND: ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) proteins play an important pathological role in matrix degeneration. Aggrecan degradation is a significant and critical event in early-stage osteoarthritis. To determine the effect of hemoglobin (Hb) on the ability of synovial tissues to produce ADAMTS family members, we examined the influence of Hb by synovial cells in an in vitro experimental system. METHODS: Synovial tissues were obtained from five young patients with meniscal injury under arthroscopic surgery. Primary cultures of human knee synovial cells were treated with different doses of human Hb (0, 25, 50, 100 µg/ml). The culture media were collected 24 h after Hb-treatment. In the time-course studies, cells were treated with and without 100 µg/ml Hb, and culture media were taken at 6, 12, and 24 h. To identify the proteins responsible for aggrecanase activity, Western blot analysis using antibodies against human ADAMTS-5, -8, -9, and -10; enzyme-linked immunosorbent assay (ELISA); and gene expression for ADAMTS-5 and -9 were examined. Statistical comparisons between each group were performed using paired t-tests. RESULTS: Western blot analysis revealed that Hb-treatment resulted in the expression of ADAMTS-5 and -9. Neither control group nor Hb-treated medium showed immunoreactivity against ADAMTS-8 or -10. In a dose-dependency study, the Hb-treated group showed significantly higher levels of ADAMTS-5 and -9 compared with the control (p < 0.05). There was no significant difference between 25, 50, and 100 µg/ml Hb-treated groups. In a time-course study, the ADAMTS-5 and -9 levels in the conditioned medium had significantly increased expression at 6, 12, and 24 h in the Hb-treated group (p < 0.05). Hb evoked significant expression of ADAMTS-9 mRNA at 12 and 24 h (p < 0.05). CONCLUSIONS: These findings indicate that Hb induces the expression of ADAMTS-5 and -9 by synovial cells at low doses, even at an acute phase, and suggests a possible role for Hb in cartilage damage after intra-articular hemorrhage. The results also suggest a new potential therapeutic target by inhibiting the activities of ADAMTS-5 and -9 to prevent cartilage damage after intra-articular hemorrhage.

Thrombin activatable fibrinolysis inhibitor activation and bleeding in haemophilia A.

Individuals with haemophilia A exhibit bleeding tendencies that are not always predicted by their factor (F)VIII level. It has been suggested that bleeding in haemophilia is due not only to defective prothrombin activation but also aberrant fibrinolysis. Thrombin activatable fibrinolysis inhibitor (TAFI) activation was measured in tissue factor (TF)-initiated blood coagulation in blood samples of 28 haemophiliacs and five controls. Reactions were quenched over time with FPRck and citrate and assayed for TAFIa and thrombin-antithrombin (TAT). The TAFIa potential (TP), TAFI activation rate and the TAFIa level at 20 min (TAFIa(20 min)) was extracted from the TAFI activation progress curve. In general, the time course of TAFI activation follows thrombin generation regardless of FVIII activity and as expected the rate of TAFI activation and TP decreases as FVIII decreases. The magnitude of TP was similar among the control subjects and subjects with <11% FVIII. In severe subjects with <1% FVIII at the time of blood collection, the TAFIa(20 min) was inversely and significantly correlated with haemarthrosis (-0.77, P = 0.03) and total bleeds (-0.75, P = 0.03). In all cases, TAFIa(20 min) was more strongly correlated with bleeding than TAT levels at 20 min. Overall, this study shows that TAFI activation in whole blood can be quantified and related to the clinical bleeding phenotype. Measuring TAFIa along with thrombin generation can potentially be useful to evaluate the differential bleeding phenotype in haemophilia A.

Evaluation of the efficacy and safety of etoricoxib in the treatment of hemophilic arthropathy.

This 2-part, double-blind, placebo-controlled study was conducted to determine the safety and efficacy of etoricoxib, a COX-2 selective inhibitor, for the treatment of hemophilic arthropathy. In part 1 (6 weeks), 102 patients (> or = 12 years old) with hemophilic arthropathy were randomized to receive 90 mg etoricoxib once daily or placebo (1:1 ratio). In part 2 (6 months), 51 patients taking placebo in part 1 were randomized to receive 90 mg etoricoxib or 25 mg rofecoxib once daily; patients taking etoricoxib in part 1 continued the same treatment. Efficacy end points included Patient Assessment of Arthropathy Pain, Patient Global Assessment of Arthropathy Disease Status, and Investigator Global Assessment of Arthropathy Disease Status. Safety was evaluated at each study visit. Etoricoxib provided significant improvement in all end points versus placebo (P < .001). Fewer patients taking etoricoxib discontinued due to a lack of efficacy versus placebo (P = .048). During part 2, efficacy was maintained; etoricoxib and rofecoxib demonstrated similar results. The most common adverse experiences were upper respiratory infection and headache. The incidence of joint bleeding during part 1 was similar between etoricoxib (66.7%) and placebo (72.6%) and during part 2 between etoricoxib (77.0%) and rofecoxib (78.9%). We conclude that etoricoxib provided superior efficacy versus placebo for the treatment of hemophilic arthropathy and was generally safe and well tolerated.

Differential patterns of PMN-elastase and type III procollagen peptide in knee joint effusions due to acute and chronic sports injuries.

In 38 traumatic knee joint effusions the proteolytic enzyme PMN-elastase (PMN-E) and the repair marker procollagen III aminoterminal peptide (PIIINP) were determined. According to the period between trauma and first aspiration of the effusion, the patients were divided into 3 groups. Group I (17 patients; period between trauma and first aspiration not longer than 72 hours) showed high concentrations of PMN-E (up to 5400 ng/ml) and low concentrations of PIIINP (less than 13 U/ml). Group II (11 patients; aspiration within 4 to 14 days) had mean PMN-E and PIIINP concentrations of 125.6 ng/ml and 52.1 U/ml, respectively. In group III (10 patients, aspiration after 14 days) mean PMN-E concentration was 123.8 ng/ml and mean PIIINP concentration was 63.4 U/ml. Graphic depiction of PMN-E and PIIINP levels in each individual sample as a function of time between trauma and fluid collection revealed highly increasing PMN-E levels during the first 24 posttraumatic hours, followed by rapidly decreasing levels within 72 hours post trauma, and no change after the 4th posttraumatic day. In contrast, PIIINP increased continuously up to the first posttraumatic week and stayed at high levels up to 90 days (end of the observation period). The differential patterns of PMN-E and PIIINP concentration in knee joint effusions may be useful in estimating the period between trauma and first treatment (aspiration of effusion) and should, therefore, be helpful in detecting degenerative lesions, which seem to be characterized by low PMN-E concomitantly with high PIIINP levels.

Early biochemical and histological findings in experimental hemarthrosis in dogs.

This study reports on the early findings in experimental hemarthrosis. Biochemical and histological analyses show the first signs of cartilage degeneration secondary to the presence of blood in the joint, and this for a certain duration. The lower limits of amount and duration, necessary to produce a reaction in synovium and cartilage are determined. Evidence is also given that the production of degradative enzymes, by the synovium especially, plays an important role, in the early phase of cartilage degeneration. A few hypotheses are discussed.

I-Naphthyl acetate esterase isoenzymes in synovial fluids and radiography of temporomandibular and knee joints.

Esterase isoenzymes of synovial fluids were presented in cases of pain-dysfunction syndrome, osteoarthrosis, osteochondroma, malignant fibrous histiocytoma of temporomandibular joint, and hemarthrosis, rheumatoid arthritis of the knee joint. Radiographic features of them were also comparatively presented in several cases. The electrophoretogram of I-Naphthyl acetate esterase of pain-dysfunction syndrome showed the esterase-I, while when inflammatory process developed at joints, electrophoretic pattern of synovial fluids revealed a rather similar feature of sera with variable stainabilities of esterase-I, and -III, irrespective of any inflammation. Osteochondroma showed two components of esterase-I and -III, on the other hand malignant fibrous histiocytoma presented esterase-I and -III in the early stage but a more complicated pattern in recurrence. Among these conditions, the most similarity between synovial fluid and serum was demonstrated in the case of hemarthrosis on the electrophoretogram of I-Naphthyl acetate esterases.