Inhibitory Effect of a Tankyrase Inhibitor on Mechanical Stress-Induced Protease Expression in Human Articular Chondrocytes.

We investigated the effects of a Tankyrase (TNKS-1/2) inhibitor on mechanical stress-induced gene expression in human chondrocytes and examined TNKS-1/2 expression in human osteoarthritis (OA) cartilage. Cells were seeded onto stretch chambers and incubated with or without a TNKS-1/2 inhibitor (XAV939) for 12 h. Uni-axial cyclic tensile strain (CTS) (0.5 Hz, 8% elongation, 30 min) was applied and the gene expression of type II collagen a1 chain (COL2A1), aggrecan (ACAN), SRY-box9 (SOX9), TNKS-1/2, a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), and matrix metalloproteinase-13 (MMP-13) were examined by real-time PCR. The expression of ADAMTS-5, MMP-13, nuclear translocation of nuclear factor-κB (NF-κB), and ß-catenin were examined by immunocytochemistry and Western blotting. The concentration of IL-1ß in the supernatant was examined by enzyme-linked immunosorbent assay (ELISA). TNKS-1/2 expression was assessed by immunohistochemistry in human OA cartilage obtained at the total knee arthroplasty. TNKS-1/2 expression was increased after CTS. The expression of anabolic factors were decreased by CTS, however, these declines were abrogated by XAV939. XAV939 suppressed the CTS-induced expression of catabolic factors, the release of IL-1ß, as well as the nuclear translocation of NF-κB and ß-catenin. TNKS-1/2 expression increased in mild and moderate OA cartilage. Our results demonstrated that XAV939 suppressed mechanical stress-induced expression of catabolic proteases by the inhibition of NF-κB and activation of ß-catenin, indicating that TNKS-1/2 expression might be associated with OA pathogenesis.

Influence of Janus kinase inhibitors on early postoperative complications in patients with rheumatoid arthritis undergoing orthopaedic surgeries.

OBJECTIVE: We retrospectively reviewed the records of rheumatoid arthritis (RA) patients who underwent orthopaedic surgery to examine the influence of the perioperative use of Janus kinase (JAK) inhibitors on early postoperative complications. PATIENTS AND METHODS: Thirty-two patients with RA under disease control with JAK inhibitors who underwent 49 orthopaedic procedures were included in the study. Patient records after surgery were investigated for surgical site infection (SSI), delayed wound healing (DWH), a flare-up of the disease, preoperative and postoperative absolute lymphocyte counts (ALCs), venous thromboembolism, and other postoperative complications. RESULTS: JAK inhibitors were continued during the perioperative period in 31 procedures. In the remaining 18 procedures, JAK inhibitors were discontinued perioperatively with a mean discontinuation period of 2.4 days. No instances of SSI were identified in any patient during at least 90 days' follow-up, while DWH was seen in one patient. Disease flare-up was noted in two patients after 3 and 9 days of discontinuation of JAK inhibitors, respectively. The ALCs significantly decreased on postoperative Day 1 (P < .0001), and there was a significant correlation between pre- and post-one-day ALCs (r = 0.75, P < .0001). CONCLUSION: JAK inhibitors seem to be safe during the perioperative period of orthopaedic surgery.