Histopathologic and Immunohistochemical Sequelae of Bariatric Embolization in a Porcine Model

Purpose: To evaluate the histopathologic sequelae of bariatric embolization On the gastric mucosa and to correlate with immunohistochemical evaluation of the gastric fundus, antrum, and duodenum. Materials and Methods: This study was performed on 12 swine stomach and duodenum specimens after necropsy. Of the 12 swine, 6 had previously undergone bariatric embolization of the gastric fundus, and the 6 control swine had undergone a sham procedure with saline. Gross pathologic, histopathologic, and immunohistochemical examinations of the stomach and duodenum were performed. Specifically, mucosal integrity fibrosis, ghrelin-expressing cells, and gastrin-expressing cells were assessed. Results: Gross and histopathologic evaluation of treatment animals showed healing or healed mucosal ulcers in 50% of animals, with gastritis in 100% of treatment animals and in five of six control animals. The ghrelin-immunoreactive mean cell density was significantly lower in the gastric fundus in the treated animals compared with control animals (15.3 vs 22.0, P < .01) but similar in the gastric antrum (9.3 vs 14.3, P = .08) and duodenum (8.5 vs 8.6, P = .89). The gastrin-expressing cell density was significantly lower in the antrum of treated animals compared with control animals (82.2 vs 126.4, P = .03). A trend toward increased fibrosis was suggested in the gastric fundus of treated animals compared with controls (P = .07). Conclusions: Bariatric embolization resulted in a significant reduction in ghrelin-expressing cells in the gastrin fundus without evidence of upregulation of ghrelin-expressing cells in the duodenum. Healing ulcerations in half of treated animals underscores the need for additional refinement of this procedure.