Association of serum VEGF with clinical response to anti-TNFα therapy for Crohn's disease.

Down-regulation of immune-mediated angiogenesis seems to be an important mechanism in anti-tumor necrosis factor α (anti-TNFα) therapy for Crohn's disease (CD). However, it remains to be established whether the baseline pro-angiogenic activity as reflected by the level of vascular endothelial growth factor (VEGF) could be of predictive value for successful clinical outcome of such treatment. Here, the levels of serum VEGF and other crucial angiogenesis-regulating peptides were assessed before and after induction anti-TNFα therapy in CD patients, and in age- and sex-matched healthy controls. Clinical, endoscopic, and biochemical activity of CD was estimated in parallel. CD patients were divided into two subgroups, depending on baseline VEGF levels: a "low-VEGF" subgroup with VEGF levels similar to those detected in healthy people, and a "high-VEGF" subgroup with VEGF levels significantly increased. VEGF levels were found to significantly correlate with CD clinical activity. Compared to the "low-VEGF" subgroup, the reduction in CD clinical activity as assessed by Crohn's Disease Activity Index was significantly greater in "high-VEGF" patients both in absolute numbers, and as a percentage of pre-treatment values. Accordingly, the fraction of patients who did not respond adequately to treatment was significantly greater in the "low-VEGF" group. These data indicate that VEGF may serve as an additional marker of CD activity and that baseline VEGF levels can be helpful in predicting the efficacy of anti-TNFα therapy.