Hypoxia-inducible factor 1 alpha and vascular endothelial growth factor overexpression in ischemic colitis.

OBJECTIVE

To examine the etiology and pathophysiology in human ischemic colitis from the viewpoint of ischemic factors such as hypoxia-inducible factor 1 alpha (HIF-1 alpha and vascular endothelial growth factor (VEGF).

METHODS

Thirteen patients with ischemic colitis and 21 normal controls underwent colonoscopy. The follow-up colonoscopy was performed in 8 patients at 7 to 10 d after the occurrence of ischemic colitis. Biopsy samples were subjected to real-time RT-PCR and immunohistochemistry to detect the expression of HIF-1 alpha and VEGF.

RESULTS

HIF-1 alpha and VEGF expression were found in the normal colon tissues by RT-PCR and immunohistochemistry. HIF-1 alpha and VEGF were overexpressed in the lesions of ischemic colitis. Overexpressed HIF-1 alpha and VEGF RNA quickly decreased to the normal level in the scar regions at 7 to 10 d after the occurrence of ischemic colitis.

CONCLUSIONS

Constant expression of HIF-1 alpha and VEGF in normal human colon tissue suggested that HIF-1 alpha and VEGF play an important role in maintaining tissue integrity. We confirmed the ischemic crisis in ischemic colitis at the molecular level, demonstrating overexpression of HIF-1 alpha and VEGF in ischemic lesions. These ischemic factors may play an important role in the pathophysiology of ischemic colitis.