Angiogenesis and Vascular Endothelial Growth Factor-A Expression Associated with Inflammation in Pediatric Crohn's...

Angiogenesis is a component of chronic inflammatory diseases including inflammatory bowel disease. Some studies describe increased angiogenesis associated with acute disease in adult Crohn's disease and ulcerative colitis, while animal models aid investigations of mechanism and pathophysiology of angiogenesis. We aim to explore the role of angiogenesis and its pathways in pediatric Crohn's disease.

Surgical specimens were obtained from pediatric Crohn's disease (both inflamed and non-inflamed regions of ileum) and control patients. Samples were examined for inflammation, microvessel density, and molecular expression of vascular endothelial growth factor-A, platelet-derived growth factor-β, angiopoietin-1, and angiopoietin-2.

Angiogenesis and inflammation were increased in parallel in Crohn's disease compared to controls. We also discovered increased angiogenesis in Crohn's disease tissue that was relatively free of inflammatory disease. Vascular endothelial growth factor-A gene expression (P = 0.034) was elevated in Crohn's disease over controls, while gene expression of platelet-derived growth factor-β (P = 0.069), angiopoietin-1 (P = 0.206), and angiopoietin-2 (P = 0.082) was not significantly elevated.

We confirm that inflammation-associated angiogenesis is upregulated in pediatric Crohn's disease. This population also exhibits elevated mucosal angiogenesis at the surgical margin with limited inflammation. This suggests that angiogenesis is an additional pathologic characteristic to potentially identify normal mucosa and margins of surgical resection that are uninvolved with disease and, furthermore, may have implications for monitoring complete disease remission. We further identify the vascular endothelial growth factor-A pathway involvement in the disease process, which may serve as a future molecular target for anti-angiogenic therapy in inflammatory bowel disease.