Effect of tranexamic acid (Cyklokapron) on the synthesis of chondroitin sulphate and the content of hexosamine in the same fraction on normal and degenerated joint cartilage in the rabbit

Short exposure to tranexamic acid does not affect, in vitro, the viability of human chondrocytes

BACKGROUND

Only few studies have investigated the effect of topical application of tranexamic acid (TXA) on "minimally" invasive joint surgical procedures in which articular cartilage is preserved; for this reason, actually many surgeons avoid the use of topical TXA even if the disadvantage related to a blood loss can occur. The aim of this study was to evaluate the cytotoxicity, on human chondrocytes, of TXA at different concentrations and times of exposure and the mechanisms of cell death.

METHODS

Experiments were carried out on isolated human chondrocytes harvested from eight patients who underwent total knee replacement. Cell viability was determined using XTT assay and was assessed at 0, 24 and 48 h intervals after a 10-min-long treatment, followed by thorough washes, or at 24 and 48 h of treatment at TXA concentrations of 20, 50, 70 and 100 mg/ml. Cell cycle alterations and occurrence of cell death for apoptosis or necrosis were assessed by cytofluorimetry. Data were analyzed using Proc Mixed Procedure; LSMEANS was used to compare multiple group means with Tukey's honestly significant difference test.

RESULTS

A significant correlation between the controlled for factors (type of treatment, time and concentration) was found in the performed experiment. No significant effect on cell viability was observed when the TXA exposure was limited to 10 min, while for increased exposure, 24 and 48 h, a remarkable reduction was found; cell death occurred by apoptosis and was already appreciable after 24 h, reaching a statistical significance after the 48-h-long treatment.

CONCLUSION

A prolonged exposure to TXA may cause cartilage damage, thus its topical application can be expanded also to clinical scenarios that include retention of native cartilage chondrocytes, only if it is limited to few minutes and used at concentrations of 70 mg/ml or less.

A new model of osteoarthritis in rabbits. III. Evaluation of anti-osteoarthritic effects of selected drugs administered intraarticularly

A battery of steroidal and nonsteroidal antirheumatic drugs and protease inhibitors were tested by intraarticular injection for effects on osteoarthritis of the knees of rabbits subjected to partial lateral meniscectomy and section of the sesamoid and collateral fibular ligaments. Among the standard drugs, only the glucocorticoid, triamcinolone hexacetonide, and the protease inhibitor, tranexamic acid, exhibited significant anti-osteoarthritic activity. An experimental drug, GPA 2163, also offered some protection against joint degeneration. The nonsteroidal antiinflammatory drugs had no effect on the development of osteoarthritis in the model.

The pathogenesis of osteoarthrosis

Recent investigations on protease inhibitors in articular cartilage have provided new insights into the possible initial lesions of osteoarthrosis. A hypothesis has been formulated based upon an impaired ability of chondrocytes to synthesize protease inhibitors, which leads to loss of matrix integrity and vascular invasion from subchondral bone and the joint margins.

Diffusion of tranexamic acid to the joint

Tranexamic acid (Cyklokapron, Kabi, Stockholm) in a dose of 10 mg per kg body weight was given i.v. to 17 patients at various intervals before operation on the knee joint, in order to elucidate the diffusion of the drug to the joint fluid and the synovial membrane. The acid diffused rapidly to both the above tissues, and in the joint fluid it reached the same concentration as in the serum. The biologic half-time in the joint fluid was about 3 hours. In the treatment of joint bleedings in hemophiliacs and in association with intra-articular operations on such patients tranexamic acid is a suitable supplement to conventional substitution therapy.