Preclinical evaluation of a novel thermally sensitive co-polymer (LiftUp) for endoscopic resection

Potential of temperature-response collagen-genipin sol as a novel submucosal injection agent for endoscopic resection: Acute and chronic phase study using living animals

OBJECTIVES

We proposed a novel temperature-response collagen sol as a submucosal injection agent for endoscopic resection (ER) using pepsin-solubilized collagen (PSC) and genipin (Ge) in a prior study. This study aimed to evaluate the usefulness and safety of the sol (PSC/Ge) in acute and chronic phase experiments using living animals.

METHODS

In experiment 1, we performed endoscopic submucosal dissection (ESD) for six pigs using normal saline (NS), sodium hyaluronate (SH), and PSC/Ge. We compared the required amount of each agent per unit area and procedure time. In experiment 2, we created artificial ulcers with endoscopic mucosal resection (EMR) for five pigs using NS and PSC sol. We compared the artificial ulcer residual rate at 7 and 14 days after EMR, and the scarring rate at 14 days after EMR.

RESULTS

The required amount of agents per unit area for PSC/Ge (0.8 ± 0.8 mL/cm² ) and SH (1.1 ± 0.8 mL/cm² ) were significantly smaller than that for NS (1.8 ± 0.7 mL/cm² ). The total procedure time did not have a statistical difference. The artificial ulcer residual rates were 47.3 ± 0.7% for NS and 40.3 ± 0.7% for PSC/Ge on day 7 (P = 0.51), and 15.0 ± 0.1% for NS and 10.2 ± 0.1% for PSC/Ge sol on day 14 (P = 0.35). The scarring rate on day 14 was 10% for NS and 20% for PSC/Ge.

CONCLUSION

We demonstrated the feasibility of a novel temperature-response collagen gel as a submucosal injection agent for ER in the acute and chronic phase animal experiment.

Near-focus mode for accurate operation during endoscopic submucosal tunneling procedure

INTRODUCTION

When using the endoscopic submucosal tunnel technique (ESTT), the working space in the submucosal tunnel is limited, and the visual field is obscured during close inspection or hemostasis. We aimed to evaluate the efficacy and safety of near-focus mode technique for accurate operation during the submucosal tunneling endoscopic procedure.

MATERIAL AND METHODS

A retrospective two-center study was designed. A total of 51 patients undergoing ESTT procedures with near-focus mode (n = 29) or traditional mode (n = 22) between February 2016 and May 2019 were included in this study.

RESULTS

When using the near-focus mode during the ESTT procedure, it is convenient to ensure a clear image and accurate operation. Adverse events occurred more frequently in the traditional group than in the near-focus group (45.5% vs 17.2%, p = .036). The near-focus group exhibited a lower rate of bleeding compared to the traditional group (0 vs 18.2%, p = .029). Furthermore, the mean hospital stay after the procedure was shorter in the near-focus group than in the traditional group (5.7 days vs 6.7 days, p = .013).

CONCLUSIONS

The visual field is more clearly exposed during submucosal tunneling when using the near-focus mode than when using traditional procedures. This technique appears to be more efficient and secure than the traditional ESTT procedure.

Efficacy and safety of a novel submucosal injection solution for endoscopic resection in porcine models

OBJECTIVE

A submucosal injection is usually required to improve the efficacy and safety of endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR). This study aimed to evaluate the performance of 3.3% sodium carboxymethyl starch (Na-CMS) solution, a novel submucosal injection solution, for ESD and EMR.

METHODS

Na-CMS, normal saline (NS) and two commercially available agents (sigMAVisc and Eleview) were injected into the esophageal submucosa of randomly grouped pigs. The level of submucosal elevation was examined. Subsequently, ESD or EMR procedures using 3.3% Na-CMS or NS as submucosal injections were performed in the gastrointestinal tract of the pigs.

RESULTS

Submucosal elevation was significantly higher and more sustained in the 3.3% Na-CMS group than in the controls (P < 0.05). The volume required for ESD or EMR was significantly lower in the 3.3% Na-CMS group than in the NS group (ESD: 12.21 ± 4.09 mL vs 28.25 ± 8.02 mL, P < 0.001; EMR: 3.99 ± 1.98 mL vs 7.15 ± 3.67 mL, P = 0.001). The ESD resection time was significantly shorter in the 3.3% Na-CMS group than in the NS group (16.58 ± 7.30 min vs 25.29 ± 11.89 min, P = 0.004). Hemorrhage after ESD in the 3.3% Na-CMS group was less severe than that in the NS group (P = 0.006).

CONCLUSION

3.3% Na-CMS is an effective, safe and low-cost submucosal injection solution and holds promise as preferable agent for submucosal injection in ESD and EMR procedures.

Novel technique for endoscopic en bloc resection (EMR+) - Evaluation in a porcine model

BACKGROUND

Endoscopic en bloc resection of larger polyps is relevant because risk of advanced neoplasia or malignancy correlates with tumor size. Recurrence rates after piecemeal endoscopic mucosal resection (EMR) are high and endoscopic submucosal dissection (ESD) is associated with higher complication rates in the western world.

AIM

To develop a modified endoscopic en bloc resection technique using an external additional working channel and novel agent for submucosal injection.

METHODS

EMR+ was considered as modified grasp and snare technique. For simultaneous use of a grasping and cutting device a novel additional working channel was used (AWC^®, Ovesco Endoscopy, Tübingen, Germany). AWC^® is installed on the outer surface of the endoscope, covered with a plastic sleeve and designed for single use. For submucosal injection a new agent consisting of poloxamers was used (LiftUp^®, Ovesco Endoscopy, Tübingen, Germany). The agent is liquid at room temperature and forms a stable and permanent gel cushion after injection. Safety of LiftUp^® has been shown in a pre-clinical study in domestic pigs. LiftUp^® is commercially not yet available but approval is expected in early 2019. EMR+ was first developed ex vivo (explanted pig stomach) and subsequently evaluated in vivo (stomach, porcine model, 3 domestic pigs). Main outcome measurements were: Procedure time, macroscopic en bloc resection and adverse events.

RESULTS

Concept of EMR+ was first developed ex vivo (explanted pig stomach). Ex vivo, 22 resections were performed after technique was established. Median procedure time (measured from begin of injection to extraction of resection specimen) was 7 min (range 5-11, SD 1.68) and median size of resection specimens was 30 mm × 26 mm × 11 mm ex vivo. Subsequently 13 resections were performed in vivo (stomach, porcine model, 3 domestic pigs). In vivo, median procedure time (measured from begin of injection to extraction of resection specimen) was 5 min (range 3-12, SD 2.72) and median size of resection specimens was 35 mm × 35 mm × 11 mm. In vivo, resection was macroscopic complete in 92.3%, major adverse events were not observed. In one case (7.7%) minor periprocedural bleeding was observed and managed by coagulation.

CONCLUSION

EMR+ appeared to be effective and safe and was easy and fast to perform in the porcine model. EMR+ needs to be further evaluated clinically in comparative trials.