Deployment of carboxymethyl cellulose sheets to prevent esophageal stricture after full circumferential endoscopic submucosal dissection: A porcine model

Research on triamcinolone-loaded thermosensitive chitosan hydrogels for preventing esophageal stricture induced by endoscopic submucosal dissection

Early-stage esophageal cancer is primarily treated by endoscopic submucosal dissection (ESD). However, extensive mucosal dissection creates a significant risk of postoperative esophageal stricture. Clinically, postoperative stricture can be prevented by glucocorticoids; however, there are drawbacks to both systemic and local administration of glucocorticoids, and improving drug administration methods is crucial. In this study, we developed a chitosan-based thermosensitive hydrogel for triamcinolone (TA) delivery. Our results indicated that the hydrogel remains liquid at low temperatures and can be injected into the esophageal wound site through an endoscopic biopsy channel. Upon reaching body temperature, the hydrogel undergoes spontaneous gelation and firmly adheres to the wound surface. The liquid phase enables convenient and precise delivery, while the gel phase achieves remarkable adhesion, tensile strength, and resistance to degradation. Moreover, the hydrogel exhibited an extended release duration of >10 days when loaded with a 10 mg dose. In vitro studies revealed that the hydrogel suppresses the proliferation and fibrogenesis of human scar fibroblasts (HKF). In a rat skin dermal defect model, the hydrogel attenuated keloid formation during the healing process. Consequently, the chitosan-based thermosensitive hydrogel developed in this study for triamcinolone delivery may be an effective tool for preventing post-ESD esophageal stricture.

Progress in the treatment and prevention of esophageal stenosis after endoscopic submucosal dissection

The primary treatment for early esophageal cancer and precancerous lesions is endoscopic submucosal dissection (ESD). However, this approach leads to a high incidence of postoperative esophageal stenosis, which can significantly impact a patient's quality of life. While various methods are available to prevent post-ESD esophageal stenosis, their effectiveness varies. Therefore, this study aims to provide an overview of the currently employed methods for preventing post-ESD esophageal stenosis in clinical practice in view of assisting clinical practitioners.

A novel tetra-PEG based hydrogel for prevention of esophageal stricture after ESD in a porcine model

Endoscopic submucosal dissection (ESD) is an accepted treatment for early esophageal cancer and precancerous lesions, but resection of a large mucosal area often leads to postoperative esophageal stricture. Biomaterials provide a new option for the treatment of post-ESD ulcers. In this study, we developed a well-defined ammonolysis-based tetra-armed poly (ethylene glycol) (Tetra-PEG) hydrogel and investigated its efficacy and related mechanisms for preventing esophageal ESD-induced stricture in a porcine model. In terms of material properties, Tetra-PEG hydrogel present great biocompatibility，great capability to retain moisture, strong tissue adhesion and high mechanical strength. Then, six domestic female pigs were randomly divided into PEG (n = 3) and control groups (n = 3). A 3/4 of the esophageal circumference ESD was performed in all pigs. In PEG group, Tetra-PEG hydrogel was easily delivered via endoscopy and adhered to the ulcer bed tightly. Compared to control group, Tetra-PEG hydrogel accelerated esophageal ulcer healing at an early stage with enhanced epithelium regeneration, milder inflammation and lesser fibrosis by regulating TGF-β/Smad2 signaling. Taken together, our findings reveal Tetra-PEG hydrogel is a promising and attractive candidate for preventing the formation of fibrotic stricture in the process of esophageal ESD-induced ulcer repair.

Acellular Dermal Matrix Prevents Esophageal Stricture After Full Circumferential Endoscopic Submucosal Dissection in a Porcine Model

Esophageal stricture is a common complication after endoscopic submucosal dissection (ESD), especially in full circumferential ESD. This study investigated fully covered self-expanding metal stent (FCSEMS) placement with an acellular dermal matrix (ADM) for preventing post-ESD esophageal stricture. Twelve Bama minipigs were randomly divided into two groups, which underwent full circumferential ESD in the distal esophagus. In group A, an FCSEMS with ADM was placed at the mucosal defect, whereas group B underwent standard FCSEMS placement. The stent was removed during gastroscopy 2 weeks after the ESD procedure. At the fourth week, gastroscopy was repeated to evaluate local healing and stenosis. The animals were sacrificed, esophageal specimens were obtained for macroscopic and histological evaluation, and serum C-reactive protein (CRP) levels were quantified. Four weeks post ESD, dysphagia occurrence was lesser in group A than in group B. Group A demonstrated lesser esophageal stricture on macroscopic evaluation (21.02 ± 16.65% vs. 57.41 ± 8.48%, p = 0.001) in the form of enhanced re-epithelization (99.13 ± 0.98% vs. 96.63 ± 1.64%, p = 0.009), diminished submucosal fibrosis (1117.53 ± 188.83 um vs. 1834.69 ± 421.99 um, p = 0.003), and attenuated inflammatory infiltration (121.00 ± 30.66 vs. 188.17 ± 64.92, p = 0.045). The increase in the serum CRP level was lower in group A than in group B at 4 weeks post-ESD. FCSEMS combined with ADM can enhance re-epithelization in the process of wound healing and significantly reduce the degree of esophageal stenosis after circumferential ESD. This study provided important preclinical findings for subsequent clinical trials.

Recent Advances of Biomedical Materials for Prevention of Post-ESD Esophageal Stricture

Esophageal stricture commonly occurs in patients that have suffered from endoscopic submucosal dissection (ESD), and it makes swallowing difficult for patients, significantly reducing their life qualities. So far, the prevention strategies applied in clinical practice for post-ESD esophageal stricture usually bring various inevitable complications, which drastically counteract their effectiveness. Nowadays, with the widespread investigation and application of biomedical materials, lots of novel approaches have been devised in terms of the prevention of esophageal stricture. Biomedical polymers and biomedical-derived materials are the most used biomedical materials to prevent esophageal stricture after ESD. Both of biomedical polymers and biomedical-derived materials possess great physicochemical properties such as biocompatibility and biodegradability. Moreover, some biomedical polymers can be used as scaffolds to promote cell growth, and biomedical-derived materials have biological functions similar to natural organisms, so they are important in tissue engineering. In this review, we have summarized the current approaches for preventing esophageal stricture and put emphasis on the discussion of the roles biomedical polymers and biomedical-derived materials acted in esophageal stricture prevention. Meanwhile, we proposed several potential methods that may be highly rational and feasible in esophageal stricture prevention based on other researches associated with biomedical materials. This review is expected to offer a significant inspiration from biomedical materials to explore more effective, safer, and more economical strategies to manage post-ESD esophageal stricture.

Efficacy of Sodium Carboxymethylcellulose Compared to Sodium Hyaluronate as Submucosal Injectant for Gastric Endoscopic Submucosal Dissection: A Randomized Controlled Trial

INTRODUCTION

Sodium hyaluronate (SH) is a useful submucosal injectant for gastric endoscopic submucosal dissection (ESD). On the other hand, sodium carboxymethylcellulose (SCMC), which has high viscosity, has also been applied clinically. We evaluated the efficacy of SCMC compared to that of SH in gastric ESD.

METHODS

A prospective randomized controlled trial was conducted to assess the efficacy of 1.0% SCMC as the injectant (SCMC group) compared to 0.4% SH (SH group) for ESD of gastric neoplasms. The primary end point was the procedure time of ESD. Secondary end points were treatment outcomes such as en bloc and R0 resection rates, number of hemostases, amount of injectant, ease of treatment (visual analog scale, 1-10 points), adverse events, and rate of ulcer healing 8 weeks after ESD.

RESULTS

A total of 60 patients were enrolled between October 2014 and October 2018, and 30 patients were allocated in each group. The procedure time (mean ± SD, minutes) was not significantly different between the SCMC (74.7 ± 54.5) and SH groups (67.1 ± 41.4) (p = 0.547). Furthermore, there were no differences between the 2 groups in terms of en bloc and R0 resection rates, number of hemostases, amount of injectant, ease of treatment, and rate of ulcer healing. No serious adverse events were observed in either group.

CONCLUSION

SCMC was comparable to SH in terms of procedure time, treatment outcome, and ease and safety of treatment in gastric ESD. Further studies are needed to demonstrate the differences between the 2 injectants.

Recent advances in early esophageal cancer: diagnosis and treatment based on endoscopy

Esophageal cancer (EC) often cannot be discovered in time because of its asymptomatic or symptom-atypical characteristics in early stage. The risk and probability of lymph node metastasis and distant metastasis increase correspondingly as the cancer aggressively invades deeper layers. Treatment regimens may be shifted to surgery and chemoradiotherapy (CRT) from endoscopic eradication therapy (EET) with poor quality of life and prognosis. It is imperative to identify dysplasia and EC early and enable early curative endoscopic treatments. Newer methods have been attempted in the clinical setting to achieve early detection at a more microscopic and precise level. Newer imaging techniques and artificial intelligence (AI) technology have been involved in targeted biopsies and will gradually unveil the visualization of pathology in the future. Early detection and diagnosis are the prerequisite to choose personal and precise treatment regimens. EET has also been undergoing development and improvement to benefit more patients as the first option or the firstly chosen alternative therapy, when compared with esophagectomy. More clinical studies are needed to provide more possibilities for EET.

Impact of endoscopic submucosal dissection and epithelial cell sheet engraftment on systemic cytokine dynamics in patients with oesophageal cancer

The tumour microenvironment (TME) plays an important role in cancer development, progression, and metastasis. Various cytokines are present in the TME in oesophageal cancer. Oesophageal stricture is a major complication of endoscopic submucosal dissection (ESD) for oesophageal cancer, and inflammatory cytokines are closely related to its pathogenesis. However, the cytokine crosstalk involved in the oesophageal cancer TME and post-ESD stricture has not been fully elucidated. This study investigated the comprehensive cytokine dynamics following ESD in patients with oesophageal cancer. In addition, the effect of a novel preventive technique for post-ESD stricture, autologous cell sheet engraftment, on cytokine levels was evaluated. Various pro-inflammatory and anti-tumorigenic cytokines were elevated in patients with oesophageal cancer, and ESD transiently influenced cytokine concentrations. IL-1β and TNF-α, two major pro-inflammatory cytokines that induce oesophageal stricture, were significantly suppressed by cell sheet engraftment. In conclusion, this study revealed the distinct cytokine dynamics after ESD in patients with oesophageal cancer, together with the effect of autologous cell sheet engraftment on cytokine fluctuation. These results can accelerate research on the TME and therapeutic strategies for oesophageal cancer.

A multicenter retrospective study of the esophageal triamcinolone acetonide-filling method in patients with extensive esophageal endoscopic submucosal dissection

OBJECTIVE

Endoscopic submucosal dissection (ESD) for extensive esophageal cancer is sometimes associated with post-ESD stenosis, despite preventative steroid therapy. In this retrospective multicenter analysis, we evaluated the factors associated with therapy resistance.

MATERIALS AND METHODS

We enrolled 73 patients with 75 extensive esophageal cancers treated with ESD. Stenosis prevention was performed using two esophageal triamcinolone acetonide (TA)-fillings, and repeated if stenosis was found on follow-up. Therapy-resistance factors associated with incidence of severe stenosis requiring endoscopic balloon dilation (EBD) were evaluated, including age, gender, previous treatment history, tumor location, morphology, resection size, histologic type, invasion depth, and horizontal resection grade (HR-grade 1, ≥ 9/12 and <10/12 of the circumference; grade 2, ≥ 10/12 and <11/12; grade 3, ≥ 11/12 but not circumferential; and grade 4, entirely circumferential).

RESULTS

Severe stenosis occurred in 17.3%(13/75) of cases, with a median of two EBDs (range, 1-6 times). Severe stenosis was significantly associated with HR-grade elevation and previous treatment history (p < .05); multivariate analysis showed both as independent therapy-resistance factors (p < .05). Patients without previous treatment history demonstrated severe stenosis at 12.9%(9/70): 0%(0/26) HR-grade 1, 18.8%(3/16) grade 2, 17.6%(3/17) grade 3, and 27.3%(3/11) grade 4, showing a risk of HR-grade 2 or more resection but an acceptable stenosis prevention even after entirely circumferential resection. Conversely, patients with previous treatment history demonstrated severe stenosis at a high frequency of 80%(4/5).

CONCLUSIONS

Esophageal TA-filling is a promising stenosis-preventive steroid therapy, even in entirely circumferential ESD cases. However, HR-grade 2 or more elevation and previous treatment history were independently associated with therapy resistance.

Prevention of Stricture after Endoscopic Submucosal Dissection for Superficial Esophageal Cancer: A Review of the Literature

Endoscopic resection has been the standard treatment for intramucosal esophageal cancers (ECs) because of the low risk of lymph node metastases in the lesions. In recent years, endoscopic submucosal dissection (ESD), which can resect large ECs, has been performed. However, the risk of esophageal stricture after ESD is high when the mucosal defect caused by the treatment exceeds 3/4 of the circumference of the lumen. Despite the subsequent high risk of luminal stricture, ESD has been performed even in cases of circumferential EC. In such cases, it is necessary to take measures to prevent stricture. Therefore, in this review, we aimed to clarify the current status of stricture prevention methods after esophageal ESD based on previous literature. Although various prophylactic methods have been reported to have stricture-preventing effects, steroid injection therapy and oral steroid administration are mainstream. However, in cases of circumferential EC, both steroid injection therapy and oral steroid administration cannot effectively prevent luminal stricture. To solve this issue, clinical applications, such as tissue shielding methods with polyglycolic acid sheet, autologous oral mucosal epithelial sheet transplantation, and stent placement, have been developed. However, effective prophylaxis of post-ESD mucosal defects of the esophagus is still unclear. Therefore, further studies in this research field are needed.

Advances in the Prevention and Treatment of Esophageal Stricture after Endoscopic Submucosal Dissection of Early Esophageal Cancer

Endoscopic submucosal dissection (ESD) has become the main treatment for early esophageal cancer. While treating the disease, ESD may also cause postoperative esophageal stricture, which is a global issue that needs resolution. Various methods have been applied to resolve the problem, such as mechanical dilatation, glucocorticoids, anti-scarring drugs, and regenerative medicine; however, no standard treatment regimen exists. This article describes and evaluates the strengths and limitations of new and promising potential strategies for the treatment and prevention of esophageal strictures.

Esophageal regenerative therapy using cell sheet technology

We have been conducting research on esophageal regenerative therapy using cell sheet technology. In particular, in the endoscopic field, we have pushed forward clinical research on endoscopic transplantation of cultured autologous oral mucosal epithelial cell sheets to esophageal ulcer after endoscopic submucosal dissection (ESD). We started research in this direction using animal models in 2004 and performed clinical research in 2012 in collaboration with Nagasaki University and Karolinska Institute. Although in full-circumferential cases it was difficult to prevent esophageal stricture after ESD, there were no complications and stricture could be suppressed. The cell sheet technology is still in its infancy. However, we are convinced that it has a high potential for application in various areas of gastrointestinal science. In this review, we focus on the pre-clinical and clinical trial results obtained and on the theoretical aspects of (1) stricture prevention, (2) esophageal tissue engineering research, and (3) endoscopic transplantation, and review the esophageal regenerative therapy by cell sheet technology.

Novel detachable stents for the treatment of benign esophageal strictures

The radial force of esophageal stents may not completely change during extraction and therefore, the procedure of stent removal may cause tissue damage. The present study reports the manufacture of 2 novel detachable stents, which were designed to reduce tissue damage through their capacity to be taken or fall apart prior to removal and evaluated the supporting properties of these stents and the extent of local mucosal injury during their removal. The stents were manufactured by braiding, heat-setting, coating and connecting. The properties of the stents were evaluated by determining the following parameters: Expansion point, softening point, stent flexibility, radial compression ratio and radial force. A total of 18 rabbits with induced esophageal stricture were randomly assigned to 3 groups as follows: Detachable stent (DS) group, biodegradable stent (BS) group and control group. The stricture rate, complications, survival, degradation and stent removal were observed over 8 weeks. The stents of the DS and BS groups provided a similar supporting effect. The stricture rate, incidence of complications and survival were also similar between the 2 groups, while significant differences were noted between the DS and control groups and between the BS and control groups. In the BS group, the stents were degraded and moved to the stomach within 7 weeks (2 in 6 weeks and 3 in 7 weeks). The debris was extracted using biopsy forceps. In the DS group, all stents were easy to remove and 2 cases exhibited minor hemorrhage. In conclusion, the 2 types of novel detachable stent provided an equally efficient supporting effect in vitro and in vivo and may reduce the incidence of secondary injury during stent removal.

Strategies to prevent stricture after esophageal endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) has been widely applied as a less invasive and more effective method for treating early esophageal cancers such as squamous cell carcinoma and dysplasia of Barrett's esophagus. However, post-ESD esophageal stricture often occurs if patients suffer circumferential mucosal defects of more than three-quarters of the circumference of the esophagus, which makes it difficult for patients to swallow and greatly reduces their quality of life. Moreover, there is currently no standard method to treat post-ESD esophageal stricture, even though it is extraordinarily important to prevent its formation. In recent years, several strategies to prevent esophageal stricture have emerged. These strategies can be classified into pharmacological, mechanical, tissue engineering, and other novel strategies, with each strategy having its own strengths and weaknesses. Although the pharmacological prophylaxis and mechanical strategies are relatively mature, they still have their drawbacks like high time-consumption, the occurrence of re-stricture, and significant side effects. Tissue engineering strategies and other novel strategies have shown promising preliminary results, but more clinical trials are needed. In this review, we discuss these strategies, with a particular focus on tissue engineering strategies and other novel strategies. It is hoped that this discussion will aid in finding more effective and safer strategies to prevent esophageal stricture.

Prevention of esophageal stricture after endoscopic resection

Stricture formation after esophageal endoscopic resection has a negative impact on patients' quality of life because it causes dysphagia and requires multiple endoscopic dilations. Various methods by which to prevent stricture have recently been developed and reported. Among these methods, local steroid injection is the most commonly used and is currently considered the standard method for noncircumferential resection. However, local steroid injection has a limited effect on circumferential resection. Thus, oral steroid administration is used for such cases because it may have a stronger effect than local injection. Steroid treatment, both by local injection and oral administration, is effective and low-cost; however, it may cause fragility of the esophageal wall, resulting in adverse events such as perforation during balloon dilatation. Many innovative approaches have been developed, such as tissue-shielding methods with polyglycolic acid, tissue engineering approaches with autologous oral mucosal epithelial cell sheet transplantation, and stent insertion. These methods may be promising, but they are limited by a scarcity of data. Further investigations are needed to confirm the efficacy of these methods.