Histopathologic and Immunohistochemical Sequelae of Bariatric Embolization in a Porcine Model

Abstract

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 gastric 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.

Clinical Safety of Bariatric Arterial Embolization: Preliminary Results of the BEAT Obesity Trial

“…In a second patient, 2-week follow-up endoscopy revealed a small asymptomatic superficial ulcer in the fundus/lesser curvature that resolved by the time of 3-month follow-up endoscopy. Although superficial ulcers were expected (9)(10)(11)17), this was still reported as a minor adverse event. Two patients asked to be discharged without a hospital admission and were sent home 6 hours after the procedure.…”

A Review of Past and Present Weight Loss Strategies and the Potential Role of Bariatric Arterial Embolization

“…Interestingly, ulcers seen in preclinical studies occurred in a variety of stomach regions but spared the fundus. [98][99][100] This indicates that ulceration was caused by effects of nontarget embolization rather than a consequence of the intended embolization of fundal blood supply. It should also be noted that ulcers observed in these BAE preclinical studies were all in the healing phase and no ulcer-related bleeding or perforation events have ever been reported in the animal BAE literature.…”

“…Multiple studies have evaluated the use of microspheres in BAE in the animal population and have demonstrated strong clinical efficacy in terms of weight loss and ghrelin modulation. 95,[98][99][100][101] A histopathologic and immunochemical analysis of swine treated with microsphere embolization of the LGA revealed a significant suppression of gastrin-expressing cells (GEC) in the fundus when compared with control swine. 98 There was no compensatory increase in GEC in the duodenum of treated animals.…”

“…In several translational investigations, the incidence of healing ulcers visualized through endoscopy was noted. [96][97][98]100 Gastric ulceration is a direct manifestation of tissue ischemia which can be inadvertently caused by administering embolic material to gastric tissue. Paxton et al 99 sought to characterize factors that modulate risk of gastric ulceration but found no significant effect on ulcer quantity in swine that had varying numbers of fundal arteries embolized.…”

Bariatric Embolization of the Gastric Arteries for the Treatment of Obesity

“…After sacrifice of these animals at eight weeks, a gross pathologic examination, traditional hematoxylin and eosin staining, and a immunohistochemical analysis of the gastric mucosa and duodenum was performed (50). Approximately half of treated animals had evidence of gastric ulceration in the gastric body (not the fundus) ranging from 1.2 −7.9 cm in maximal diameter.…”