Gastric mucosal devitalization (GMD): translation to a novel endoscopic metabolic therapy

Abstract

Background and study aims The metabolic effects of bariatric surgery may partially result from removal of the gastric mucosa, an often underappreciated endocrine organ. Using argon plasma coagulation (APC), we may be able to selectively devitalize (ablate) the mucosa. The aim of this study was to identify the optimal tissue color that would correspond to selective gastric mucosal devitalization (GMD) using ex-vivo human stomach specimens. Patients and methods Stomach specimens were obtained at sleeve gastrectomy. Prior to APC application, a submucosal fluid cushion was created. APC was then applied over a 2 × 2-cm area to the fundus and body, aiming for the three indicator colors (white, golden, brown). Pathological analysis was then performed independently and in a blinded fashion by two pathologists to determine the depth of mucosal and submucosal percent thermal injury and mucosal percent cell death. Results Six patients were enrolled. There was a significant correlation between tissue color and mucosal percent thermal injury. The highest percent mucosal thermal injury was seen with brown (99.6 %, 95 % CI: 98.7, 100), followed by golden (92.5 %, 95 % CI: 85.5, 99.5), and then white (75.2 %, 95 % CI: 58.3, 92.1, P < 0.01). Submucosal thermal injury was seen in 88.9 % of the slides. Greater than minimal submucosal injury (> 10 % depth) was found significantly more with brown tissue color (91.6 %) than golden (75 %) or white (33.3 %, P < 0.05). However, 91.7 % of the entire sample set < 50 % injury. Conclusion GMD is achievable using APC without thermal injury to muscularis propria. A golden color results in sufficient mucosal injury with only superficial injury to the submucosa.

Conflict of interest statement

Competing interests Dr. Khashab is a consultant for Boston Scientific and Olympus America. Dr. Kalloo is a founding member, equity holder and consultant for Apollo Endosurgery. Dr. Kumbhari is a consultant for Pentax Medical, Boston Scientific, Apollo Endosurgery, ReShape Life Sciences, and Medtronic. He receives research support from ERBE USA and Apollo Endosurgery. Dr. Voltaggio has received salary support from C2 Therapeutics. This study was supported by Erbe Elektromedizin GmbH, Tubingen, Germany.

Figures

Fig. 1

Excised SG specimen after submucosal injection and gastric mucosal devitalization (GMD) by means of submucosal injection and argon plasma coagulation of three areas in the body and three areas in the fundus. Each gastric fundus and each gastric body had three ablated areas (one white, one golden and one brown) representing the three different devitalization dosages. The black pin indicates the body and the red pin indicates the fundus. The white pin was placed to indicate an area that was treated only with submucosal injection as control for histological analysis. A colored pin (green, blue or yellow) was placed near each ablated area and was used by the pathologist to label the tissue slides (for example, a section taken from the fundus and labeled with a blue pin would be titled “fundus blue”). From each area, microsopic sections were made for analysis.

Fig. 2 a

Flexible APC filter integrated probe for mucosal ablation with axial probe tip. bThe 3.6 FiAPC has an outer diameter (OD) of 3.6 mm/10.8 FR, a length of 2.2 m/7.2 ft, with an axial (straight fire) beam. The FiAPC 3.6 is a modified version of the commercially available 2.3 FiAPC Probe. The probe tip OD is 3.6 mm instead of 2.3 mm. An integrated ceramic tip has been added for higher thermal stability. Both FiAPC probes work in conjunction with the APC 2-Module and the VIO 300 D to ablate tissue.c, dAblation track on pig stomach tissue (body.dThe track of the 3.6 mm probe is approximately 20 % wider than the track of 2.3 probecallowing for more efficient area ablation.

Fig. 3

Image of a pathology slide of gastric mucosa after GMD showing areas of “cell death” versus “thermal injury.” The cell death region is characterized by loss and distortion of tissue structure showing a “mushy” appearance and absence of nuclei in cells. The thermal injury region is characterized by altered cell architecture with fragmented and elongated nuclei (Scale: 0.5 mm).

Fig. 4

Image of a pathology slide of gastric mucosa after GMD showing the fluid cushion in the submucosa underneath resulting in submucosal edema. Edema is an effect expected from persistence of the fluid cushion after submucosal injection and the successive argon plasma coagulation (Scale: 0.5 mm).

Fig. 5

Image of a pathology slide of gastric mucosa after GMD showing an intact muscularis propria (Scale: 0.1 mm).

Fig. 6

Image of a pathology slide demonstrating the “lifting” of the mucosa off the basement membrane (Scale: 0.5 mm).