Prostaglandin analogues

The intestinal microvasculature as a therapeutic target in inflammatory bowel disease

Chronic inflammation is a complex biologic process which involves immune as well as non-immune cells including the microvasculature and its endothelial lining. Growing evidence suggests that the microvasculature plays an integral role in the pathophysiology of inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis). The microvasculature contributes to chronic inflammation through altered leukocyte recruitment, impaired perfusion, and angiogenesis leading to tissue remodeling. These diverse areas of IBD microvascular biology represent therapeutic targets that are currently undergoing investigation.

Paradox of simultaneous intestinal ischaemia and hyperaemia in inflammatory bowel disease

This review has focused on evidence regarding intestinal perfusion of inflammatory bowel disease (IBD). Basic investigation has defined an altered microvascular anatomy in the affected IBD bowel, which corresponds with diminished mucosal perfusion in the setting of chronic, long-standing inflammation. Diminished perfusion is linked to impaired wound healing, and may contribute to the continued refractory mucosal damage, which characterizes IBD. Alterations in vascular anatomy and physiology in IBD suggests additional possible mechanisms by which micro-vessels may contribute to the initiation and perpetuation of IBD. This begs the following questions: will angiogenesis within the gut lead to sustained inflammation, does the growing vasculature generate factors that transform the surrounding tissue and does angiogenesis generate vascular anastomosis within the gut, with shunting of blood away from the mucosal surface, impairment of metabolism and potentiation of gut damage? Further studies are required to define the mechanisms that underlie the vascular dysfunction and its role in pathophysiology of IBD.

Rioprostil and ranitidine in the treatment of prepyloric gastric ulcer. A double-blind comparative trial

Rioprostil, a synthetic 16-methylprostaglandin E1, combines antisecretory with cytoprotective properties, the latter being active even at doses below those required for acid inhibition. To test whether rioprostil given in antisecretory doses would heal prepyloric ulcers rapidly, we assigned patients with endoscopically proved ulcers randomly to double-blind treatment with 100 micrograms rioprostil twice daily or 150 mg ranitidine twice daily for up to 8 weeks. Recruitment was terminated at the time point of planned interim analysis because the total healing rate was markedly lower than expected. Thirty patients were allocated to each treatment group. The cumulative healing rates at 4 and 8 weeks were 40% and 60%, respectively, in the rioprostil group versus 70% and 90%, respectively, in the ranitidine group (p less than 0.01). Pain relief occurred simultaneously in the two groups. No major adverse effects were noted. These findings question the clinical relevance of using 'cytoprotection' by prostaglandin analogues as treatment for prepyloric ulcer disease in the short term.