Factor V Leiden and the etiology of inflammatory bowel disease.

Inflammatory bowel disease (IBD) refers to two chronic diseases that cause inflammation of the intestines: ulcerative colitis and Crohn's disease. Patients suffering from IBD have a three-fold increased risk of venous thrombosis compared with matched controls. Importantly, thromboembolic disease is a significant cause of morbidity and mortality in patients with IBD. However, despite several supporting observations it is still elusive whether activation of the blood coagulation cascade is involved in the etiology and pathogenesis of IBD. To confirm or refute the hypothesis that activated blood coagulation aggravates the development of IBD, we subjected wildtype and homozygous FV Leiden mice to a model of DSS-induced colitis. Experimental colitis led to a reduction in body weight, shortening of the colon and increased colon weight. In addition, DSS treatment led to ulcerations, edema formation, crypt loss, fibrosis and the influx of inflammatory cells into the colon. However, the FV Leiden genotype had no significant effect on any of the DSS-induced symptoms of colitis. We therefore conclude that the FV Leiden allele has no effect in murine colitis and we thus question the importance of activated blood coagulation in the etiology or pathogenesis of IBD.