BLOOD DIGESTION-INDUCED SPLANCHNIC HYPEREMIA AND PORTAL BLOOD-FLOW INPORTAL HYPERTENSIVE RATS AND ROLE OF OCTREOTIDE

We aimed to investigate whether the presence of blood within the intes tinal lumen after variceal bleeding would lead to reactive intestinal hyperemia, which in turn could result in the worsening of portal hemod ynamics, and thus bleeding recurrence. Two models of portal hypertensi ve Wistar rats were used: 32 CCl4-cirrhotics with a low index of porta l-systemic shunting and 32 that had been previously subjected to porta l vein stenosis, with a high index of portal-systemic shunting; 32 Wis tar rats served as controls. The rats were divided into four groups, e ach comprising 8 cirrhotics, 8 portal vein stenosis rats, and 8 contro ls. Intestinal microcirculation and portal blood flow were assessed by laser-Doppler and transit-time ultrasonic flow probes, respectively, before and 60 min after the injection of 2 ml of blood (groups 1 and 2 ) or an equal volume of NaCl 0.9% (placebo; groups 3 and 3) into the i ntestinal lumen. Octreotide (0.2 mu g/100 g body weight [BW]) (groups 1 and 3) or NaCl 0.9% (groups 2 and 4) was then given subcutaneously, and 30 min later the final measurements were performed. The presence o f blood within the intestinal lumen resulted in an increase in intesti nal microcirculation in rats in all groups, while portal blood flow wa s increased in portal vein stenosis rats and controls, and decreased i n cirrhotics. The presence of NaCl 0.9% had no effect. Octreotide, but not NaCl 0.9%, led to a decrease in both intestinal microcirculation and portal blood flow. The findings of this study suggest that intesti nal hyperemia induced by digestion of blood in the enteric lumen incre ases or decreases portal blood How, the result being strongly related to the portal hypertension model used. Since the main difference betwe en the models was the extent of portal-systemic shunting, this may sug gest a relationship between portal blood flew and portal-systemic shun ting. This relationship could explain why variceal bleeding stops in s ome patients but recurs in others.