Peroral TAS-202 reduced vessel density in rats with adjuvant-induced arthritis

The present study was designed to investigate blood vessel density interpreted as an indirect measurement of angiogenesis following 4-(3,4,5-trimethoxyphenyl)-6-(2,4,5-trimethoxyphenyl)-2-diethylamino-pyrimidine (TAS-202) treatment in a rat model of arthritis. Male Lewis rats were inoculated intradermally with Mycobacterium butyricum into the hind paw and the arthritic responses were evaluated by measuring the changes in paw volume. Both peroral TAS-202 (10 or 30 mg/kg/day) and indomethacin (1 mg/kg/day) inhibited the autoimmune phase of the arthritic response. However, while the increase in blood vessel density in the synovial tissue was significantly inhibited by TAS-202 (10 and 30 mg/kg/day), indomethacin did not exert this effect (1 mg/kg/day). These results, together with the observation that TAS-202 in combination with indomethacin or prednisolone maintained its ability to exert an antiangiogenic effect, indicate that TAS-202 may offer promise as an oral pro-drug for the treatment of rheumatoid arthritis, through its inhibitory effect on angiogenesis at the inflammation site.