Effect of anti-inflammatory agents on the glycosaminoglycan metabolism in cultured human synovial cells

Treatment of acute superficial digital flexor tendon injury in horses with polysulphated glycosaminoglycan

Horses with acute injuries of the superficial digital flexor tendon were treated with a course of seven intramuscular injections of 500 mg of polysulphated glycosaminoglycan at four-day intervals. Clinical assessments of the lesions were made by a veterinary surgeon at the time of each injection and 14 and 28 days after the last injection. A total of 150 courses of the drug were administered and adequately completed assessment forms were returned for 80 cases. Long-term follow-up data were obtained for 19 cases. The subjective assessments by the veterinary surgeons showed that in 80 per cent of cases the drug was felt to be of value in the treatment of acute tendon injury.

Glycosaminoglycan polysulfuric acid (GAGPS) in osteoarthritis of the knee

We studied the efficacy and tolerability of glycosaminoglycan polysulfuric acid (GAGPS) in 80 patients with osteoarthritis (OA) of the knee. Patients received two series of five intra-articular injections, at 1-week intervals, of 25 mg (0.5 ml) GAGPS into the knee in a double-blind, parallel, randomized, placebo-controlled trial. There was an immediate decrease in pain after the injections of 43% with GAGPS and 33% with placebo (P = 0.047) (Jezek pain index). Pain relief of GAGPS vs placebo was not different at other intervals (10, 14, 22, 26 weeks after start of treatment). At 6 weeks the Lequesne index decreased 20% after GAGPS and 9% after placebo (P = 0.17). At 10 weeks the Lequesne index decreased 24% after GAGPS and 13% after placebo (P = 0.20). The decrease in Lequesne index at 14 weeks was 31% after GAGPS and 15% after placebo (P = 0.06). The other measured parameters tended to be more favorably influenced by GAGPS than placebo. GAGPS was well tolerated, with associated mild adverse reactions in 8% of cases. GAGPS may have a role as a symptomatic slow acting drug for OA. Further study appears appropriate.

Determination of chondroitin-6-sulphate by a competitive enzyme immunoassay using a biotinylated antigen

A competitive enzyme immunoassay was developed to determine chondroitin-6-sulphate in body fluids and cell cultures. The assay uses a monoclonal anti-chondroitin-6-sulphate antibody, immobilised to microtitre plates, and it involves a competitive binding reaction between chondroitin-6-sulphate in the samples and the biotinylated antigen. This assay enables the quantification of chondroitin-6-sulphate in the low concentration range of 16-120 micrograms/l. The intra-assay and inter-assay coefficients of variation are below 6.5% and 9.0%, respectively. More than 90% of chondroitin-6-sulphate was recovered when added to 0.1 mol/l phosphate-buffered saline, an albumin solution (40 g/l in phosphate-buffered saline) and cell culture medium (containing 100 ml/l foetal calf serum). Chondroitin-6-sulphate was also determined in sera of healthy male (n = 90) and female (n = 90) blood donors. The normal range was 55-169 micrograms/l. In men the mean value was estimated at 102.2 +/- 37.1 micrograms/l and in women at 98.7 +/- 26.4 micrograms/l. No age or sex dependence was observed. The urine excretion of chondroitin-6-sulphate in men (n = 16) was 44.5 +/- 21.1 mg/kg creatinine (mean +/- standard deviation) and in females (n = 10) 53.5 +/- 21.3 mg/kg creatinine. The clearance rate in men was 0.41 +/- 0.22 ml x min-1 and in women 0.38 +/- 0.15 ml x min-1. No sex dependence was found. Furthermore, the enzyme immunoassay was modified to measure the specific incorporation of a radioactively labelled precursor ([14C]galactosamine) into chondroitin-6-sulphate.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of tissue factor pathway inhibitor in human synovial cells and chondrocytes makes joints the predilected site of bleeding in haemophiliacs

The synthesis of tissue factor pathway inhibitor (TFPI) was investigated in cloned human synovial cells and human chondrocytes. TFPI-specific DNA transcription products of these cells were isolated, and a full-length cDNA of about 1000 base pairs was amplified by reverse transcription and polymerase chain reaction. The amplified DNA was cloned into the vector pUC 18. The TFPI coding sequence was confirmed by double stranded sequencing and was identical with that previously published for human TFPI coding nucleotide sequence from human placental cDNA (1). The inhibitory activity of TFPI in the cell medium of cultivated human chondrocytes and cloned human synovial cells was determined by a specific chromogenic substrate assay of factor Xa activity. The inhibitory activity of TFPI in the medium of human chondrocytes and cloned human synovial cells was 630-720 mU/10(8) cells and 1080-1665 mU/10(8) cells, respectively. In addition, TFPI activity in cell culture media of human chondrocytes and cloned human synovial cell was suppressed by a polyclonal goat anti-TFPI antibody directed against the inhibitory domain I and domain II. In the chromogenic substrate assay, the anti-TFPI antibody completely suppressed the inhibitory activity of TFPI in the samples.

The synthesis of hyaluronic acid by human synovial fibroblasts is influenced by the nature of the hyaluronate in the extracellular environment

Various cell lines of human synovial fibroblasts derived from synovium obtained at the time of biopsy or total joint-replacement surgery have been established. The synthesis of 3H-labelled hyaluronic acid (HA) in these cells has been determined, and the effects of adding HA of varying molecular size to the cultured cells examined. The results obtained clearly show that the in vitro synthesis of HA by these cells is influenced by the concentration and molecular weight (MW) of the HA in their extracellular environment. Synovial fibroblasts derived from an osteoarthritic joint demonstrated the most marked response on exposure to exogenous HA, showing a stimulation of HA synthesis with preparations of weight-average molecular weight (Mw) greater than 5 X 10(5) in a concentration dependent manner. HA preparations with Mw less than 5 X 10(5) showed little or no effect except at high concentrations where a suppression of biosynthesis was observed. A model to explain these findings is proposed.

Pathogenesis of degenerative joint disease

Proteoglycan degradation is central to the development of degenerative joint disease. Proteoglycans may be degraded by lysosomal enzymes from chondrocytes, synoviocytes or leucocytes. Collagen and matrix degradation occurs either by direct damage or due to degrading enzymes released into synovial fluid. Once the pathological sequence has begun it continues in a cyclic manner unless arrested by the ability of chondrocytes to synthesise sufficient matrix components. Treatment should ideally be directed to this end.