DISTORTED MICROANGIOARCHITECTURE AND IMPAIRED ANGIOGENESIS IN GASTRIC-MUCOSA OF PORTAL HYPERTENSIVE RATS

Background/Aims: Portal hypertensive (PHT) gastropathy is now recognized as a distinct entity, but the size of microvessels has been a subject of controversy. Angiogenesis in PHT gastric mucosa has not been explored. The aim of this study was to examine the angioarchitecture of PHT and non-PHT gastric mucosae before and after ethanol-induced injury utilizing microvascular cast techniques. Methods: Portal hypertension was produced by staged portal vein occlusion. Fourteen days later, gastric vascular casts were made in both PHT and control (sham-operated) rats by Mercox resin infusion. After tissue dissolution, casts were examined under a scanning electron microscope. To examine angiogenesis in injured gastric mucosa, the above study was repeated in PHT and control rats 18 hours after intragastric administration of 100% ethanol. Results: The capillary casts in PHT gastric mucosa (mean diameter, 6.3 ± 0.03 μm) were significantly narrower than those of controls (mean diameter, 8.6 ± 0.02 μm; P < 0.01). After ethanol injury, 5.5% ± 0.3% of microvessels in gastric mucosa of sham-operated rats contained buds, showing angiogenesis. In contrast, PHT gastric mucosa had a paucity of capillary angiogenesis (buds in only 0.4% +- 0.2% of microvessels; P < 0.01 vs. control). Conclusions: This study shows prominent persistent abnormalities in the microangioarchitecture of PHT gastric mucosa. Moreover, PHT gastric mucosal microvessels have a marked impairment of angiogenic response to ethanol injury. © 1994.