Hypoxia measurement of gastric conduit after esophagectomy and gastric reconstruction in rats

Abstract

Conduit ischemia is an important phenomenon related to anastomosis leakage and stricture after esophagectomy and gastric reconstruction. Clinical detection and measurement of ischemia of the gastric conduit during the postoperative period is important but difficult. In this study, optical fluorescence imaging and hypoxia Positron emission tomography (PET) imaging was studied whether it could detect the ischemia of gastric conduit in rat esophagectomy model. A rat esophagectomy model was created using 12-16-week-old, 300-350 g male Sprague-Dawley rats. In the operation group partial gastric devascularization was performed by ligating the left gastric artery and the short gastric arteries and an esophagogastric anastomosis was performed. In the control group, the esophageal-gastric junction was incised and suturing was performed without gastric devascularization. Optical fluorescence imaging with hypoxia agent and PET images with 64Cu-diacetyl-bis (N4-methylsemicarbazone) (64Cu-ATSM) were taken 24 h after the initial operation. In animal experiment, optical fluorescence imaging with hypoxia agent could not detect conduit ischemia. Hypoxia imaging with hypoxia tracer 64Cu-ATSM revealed 64Cu-ATSM uptake at the fundus in the operation group 3 h after 64Cu-ATSM injection. The maximum percentage of the injected dose per gram of tissue was higher in the operation group (0.047 ± 0.015 vs. 0.026 ± 0.006, p=0.021). The fundus/liver ratio was also higher in the operation group (0.541 ± 0.126 vs. 0.278 ± 0.049, p=0.002). Upon autoradiography, 64Cu-ATSM uptake was observed in the fundus in the operation group, and was well-correlated to that observed on the PET image. Upon immunohistochemistry, expressions of hypoxia-inducible factor 1a and pimonidazole were significantly increased at the fundus and lesser curvature compared to the greater curvature in the operation group. In conclusion, hypoxia PET imaging with 64Cu-ATSM can detect ischemia in a rat esophagectomy model. Further clinical studies are needed to verify whether hypoxia imaging may be useful in humans.