Somatostatin Attenuates the Hyperdynamic Circulatory State in the Gastric Mucosa of Rats with Portal Hypertension

Abstract

Background: Portal hypertensive gastropathy is characterized by a hyperdynamic circulatory state in the gastric mucosa. We assessed the effect of bolus injection of somatostatin on gastric mucosal perfusion in a rat model of portal hypertension. We tested the hypothesis that somatostatin will reduce gastric mucosal perfusion in portal hypertension.

Methods: Portal hypertension was induced by two-stage portal vein ligation (PVL). Two weeks after PVL significant elevation of portal venous pressure was demonstrated. Gastric mucosal hernodynamic changes were measured by reflectance spectrophotometry, which records the indexes of mucosal hemoglobin oxygen saturation (ISO₂) and mucosal hemoglobin concentration (IHB).

Results: After an intravenous bolus of 1 pg somatostatin significant reductions of ISO₂ and IHB were demonstrated in the rats with PVL (ISO₂, -34 ± 5%; IHB, -15 ± 2%) and the controls (ISO₂, -26 ± 4%; IHB, -15 ± 2%). A dose-response relationship was shown by using 0.01, 0.1, and 1 μg of somatostatin. Somatostatin did not induce other hemodynamic changes except a transient drop in systemic blood pressure of ISO₂.

Conclusion: The significant reductions of gastric mucosal ISO₂ and IHB by somatostatin support the hypothesis that somatostatin is capable of attenuating the hyperdynamic circulatory state in the gastric mucosa of rats with portal hypertension and may have a beneficial effect on portal hypertensive gastropathy. This hypothesis deserves to be evaluated in clinical studies.

Key Words:

• Gastric mucosal blood flow
• portal hypertension
• reflectance spectrophotometry
• somatostatin
• stomach