HMGB1 and rheumatoid arthritis: When RA SFs were stained after being exposed to HMGB1 (100 ng/ml) for 24 hr, VEGF was largely expressed in the perinuclear region, but after pretreatment with cilostazol (10 μM) in the presence of HMGB1, this VEGF expression was greatly diminished (Fig. 3G).