Proangiogenic/anti-angiogenic effects of Th1 and Th2 cytokines on rheumatoid arthritis fibroblast-like synoviocyte gene expression. Cell cultures were exposed to 1% oxygen (hypoxia) and/or 10 ng/ml cytokine or left untreated for 24 hours. Total RNA was isolated and cDNA generated, and the mRNA level of (a) vascular endothelial growth factor (VEGF), (c) angiopoietin-like (ANGPTL)-4, (e) leptin and (f) ephrin A3 (EFNA3) was determined using quantitative PCR. Changes in mRNA expressed as fold-change relative to levels in untreated samples set as 1.0 (dotted line). Secretion of (b) VEGF and (d) ANGPTL-4 protein was measured using ELISA. Data expressed as the mean ± standard error of the mean of ≥3 independent experiments with samples assayed in triplicate. Samples analysed using one-way analysis of variance with Bonferroni's post-hoc test for multiple comparisons versus control normoxia (†P < 0.05, ††P < 0.01, †††P < 0.001) or versus hypoxia alone (*P < 0.05, **P < 0.01,***P < 0.001).