1,25(OH)2D3 and its analogue calcipotriol inhibit the migration of human synovial and mesenchymal stromal cells in a wound healing model - A comparison with glucocorticoids.

Vitamin D analogue calcipotriol is currently used in the local treatment of psoriasis. However, it also has antiproliferative and anti-inflammatory effects in the cells of the joint - suggesting a possible benefit in local treatment of arthritis. In this study, calcipotriol was studied in different in vitro methods to find out its effect on synovial and mesenchymal stromal cells. Primary human cell lines of osteoarthritis or rheumatoid arthritis patients (five mesenchymal stromal cells, MSC, and four synovial stromal cells, SSC) were cultured to study migration and proliferation of the cells in a wound healing model. The media was supplemented with calcipotriol, 1,25(OH)2D3, dexamethasone, betamethasone, methylprednisolone or control solution in 1-100 nM concentrations. To see possible toxic effects of calcipotriol, concentrations up to 10 µM in SSCs and MSCs were studied in apoptosis and necrosis assays in four cell lines. Calcipotriol and 1,25(OH)2D3, as well as the three glucocorticoids, reduced the migration of both SSCs and MSCs. In SSCs, the effect of calcipotriol and 1,25(OH)2D3 was at least as effective as with glucocorticoids, while with MSCs, the glucocorticoids were stronger inhibitors of migration. The antimigratory of calcipotriol and 1,25(OH)2D3 was consistently maintained in 10 µM and 1 µM. Calcipotriol was not toxic to MSCs and SSCs up to concentrations of 10 µM. Calcipotriol, as well as 1,25(OH)2D3, exerts antimigratory and antiproliferative effects on human SSCs and MSCs of the joint. These effects are not caused by apoptosis or necrosis. Both calcipotriol and 1,25(OH)2D3 have similar effects as glucocorticoids without apparent toxicity, suggesting that calcipotriol might be an eligible candidate to the local treatment of arthritis with a broad therapeutic window.

No adverse effects on periarticular tissue by intra-articular vitamin D analogue calcipotriol in a reduced-dose zymosan-induced arthritis model in rats.

Calcipotriol, a vitamin D analogue, is an antiproliferative and anti-inflammatory drug currently used in psoriasis. Here, our aim was to analyse the safety of calcipotriol for cartilage and bone in alleviated-dose (0.1 mg instead of usual ≥1mg dose) zymosan-induced arthritis in rats. Theoretically, high doses of vitamin D or analogues could have detrimental effects on bone or cartilage. The rats were divided into four groups: vehicle (n = 9), dexamethasone 0.1 mg/kg (n = 9), calcipotriol 0.1 mg/kg (n = 8) and negative control (n = 10) with no injections. Arthritic rats were given phosphate-buffered saline (PBS) injections to left knees as a control. After euthanasia on day 8, all knees were imaged with micro-computed tomography for surface lesions and decalcified for histological analyses. Contrary to our expectations, no significant changes could be observed in the tomography data and histological scores among the three treatment groups or between the vehicle-treated and non-arthritic group. Calcipotriol did not cause adverse effects on cartilage or subchondral bone within a week, suggesting that it could be safely used in local treatment of arthritis. The alleviated model caused synovitis with local and systemic inflammatory response without cartilage erosions, which might be useful in studying self-limiting synovitis where cartilage or bone effects are not of primary interest.

A single intra-articular dose of vitamin D analog calcipotriol alleviates synovitis without adverse effects in rats.

1,25-dihydroxyvitamin-D3 and its derivatives have shown anti-arthritic and chondroprotective effects in experimental animal models with prophylactic dosing. The purpose of this preliminary study was to test the efficacy and safety of calcipotriol, vitamin D analog, as a treatment for a fully-developed knee arthritis in Zymosan-induced arthritis (ZIA) model. Forty 5-month-old male Sprague-Dawley rats were randomized into three arthritis groups and a non-arthritic control group with no injections (10 rats/group). A day after Zymosan (0.1 mg) had been administrated into the right knee joints, the same knees were injected with calcipotriol (0.1 mg/kg), dexamethasone (0.1 mg/kg) or vehicle in a 100 µl volume. The left control knees were injected with saline (PBS) on two consecutive days. All injections, blood sampling and measurements were performed under general anesthesia on days 0, 1, 3 and 8. Internal organs and knees were harvested on day 8 and the histology of the whole knees was assessed blinded. Joints treated with calcipotriol showed a milder histological synovitis than those treated with vehicle (p = 0.041), but there was no statistically significant difference between the dexamethasone and vehicle groups. The clinical severity of arthritis did not differ between the arthritis groups measured by body temperature, swelling of the knee, thermal imaging, clinical scoring or cytokine levels on days 1, 3 and 8. Weight loss was bigger in rats treated with dexamethasone, propably due to loss of appetite,compared to other arthritis groups on days 2-3 (p<0.05). Study drugs did not influence serum calcium ion and glucose levels. Taken together, this preliminary study shows that a single intra-articular injection of calcipotriol reduces histological grade of synovitis a week after the local injection, but dexamethasone did not differ from the vehicle. Calcipotriol may have an early disease-modifying effect in the rat ZIA model without obvious side effects.