A novel self-assembling peptide for hemostasis during endoscopic submucosal dissection: a randomized controlled trial

Systematic review of self-assembling peptides as topical agents for treatment and prevention of gastrointestinal bleeding

BACKGROUND/AIMS

Gastrointestinal bleeding is a significant and potentially lethal event. We aimed to review the efficiency and safety of self-assembling peptides for the treatment and prevention of gastrointestinal tract bleeding.

METHODS

We conducted a systematic search for studies describing the endoscopic use of self-assembling peptides for treatment or prevention of bleeding in the gastrointestinal tract in a parallel, independent fashion. The primary outcomes were rates of successful initial hemostasis, delayed bleeding, and rebleeding. The secondary outcomes were adverse events and ease and volume of gel used.

RESULTS

Seventeen studies were analyzed. Overall success rate of self-assembling peptides in gastrointestinal bleeding was 87.7% (38%-100%), regardless of etiology or associated treatments. Rebleeding rate ranged from 0% to 16.2%, with a mean of 4.7%, and overall delayed bleeding rate was 5% (range, 0%-15.9%). Only three adverse events were reported in a pooled number of 815 patients. The volume of gel used varied (0.43 to 3.7 mL) according to indication and type of bleeding.

CONCLUSIONS

The limited available data on the use of self-assembling peptides in gastrointestinal endoscopy suggest a high efficiency and good safety profile.

Spray coagulation reduces the use of hemostatic forceps for intraoperative bleeding in gastric endoscopic submucosal dissection

Aims

During intraoperative bleeding in endoscopic submucosal dissection (ESD), switching to spray coagulation may be beneficial compared with the continuous use of swift coagulation and can reduce the need for hemostatic forceps. We retrospectively assessed the effectiveness of spray modes on intraoperative bleeding during gastric ESD.

Methods and Results

A total of 316 bleeding events (156 in the Swift group and 160 in the Spray group) were consecutively recorded. In the Swift group, hemostasis was performed using the swift mode with a retracted tip of the needle-type knife, followed by the hemostatic forceps. In the Spray group, bleeding was treated in a stepwise manner: the swift mode, the spray mode, and the hemostatic forceps. All bleeding events were assigned to one of two groups by an endoscopist who retrospectively reviewed the videos. We compared the use of hemostatic forceps, the total hemostatic time, and the cumulative hemostasis rate between the two groups.The use of hemostatic forceps was significantly lower in the Spray group than in the Swift group (32.7% vs. 13.8%, P < 0.001). There was no significant difference in the total hemostatic time (Swift group, 20 s.; Spray group, 16 s.; P = 0.42), whereas the cumulative hemostasis rate with the knife was significantly higher in the Spray group (P = 0.007).

Conclusion

The results suggested that spray coagulation from the tip of the needle-type knife could reduce the use of hemostatic forceps. In gastric ESD, spray coagulation may facilitate the hemostasis of intraoperative bleeding.

Over-the-scope clip rescue method of endoscopic hemostasis for severe acute colonic diverticular bleeding

Watch a video of this article.

Updates on the Prevention and Management of Post-Polypectomy Bleeding in the Colon

Post-polypectomy bleeding (PPB) remains a significant procedure-related complication, with multiple risk factors determining the risk including patient demographics, polyp characteristics, endoscopist expertise, and techniques of polypectomy. Immediate PPB is usually treated promptly, but management of delayed PPB can be challenging. Cold snare polypectomy is the optimal technique for small sessile polyps with hot snare polypectomy for pedunculated and large sessile polyps. Topical hemostatic powders and gels are being investigated for the prevention and management of PPB. Further studies are needed to compare these topical agents with conventional therapy.

Using a novel hemostatic peptide solution to prevent bleeding after endoscopic submucosal dissection of a gastric tumor

BACKGROUND

Endoscopic mucosal dissection has become the standard treatment for early gastric cancer. However, post-endoscopic submucosal dissection (ESD) ulcer occurs in 4.4% of patients. This study hypothesized whether applying PuraStat, a novel hemostatic peptide solution, prevents post-ESD bleeding.

AIM

To investigate the preventive potential of PuraStat, a hemostatic formulation, against bleeding in post-ESD gastric ulcers.

METHODS

Between May 2022 and March 2023, 101 patients (Group P) underwent ESD for gastric diseases at our hospital and received PuraStat (2 mL) for post-ESD ulcers. We retrospectively compared this group with a control group (Group C) comprising 297 patients who underwent ESD for gastric diseases at our hospital between April 2017 and March 2021. P values < 0.05 on two-sided tests indicated significance.

RESULTS

Post-ESD bleeding occurred in 6 (5.9%) (95%CI: 2.8–12.4) and 20 (6.7%) (95%CI: 4.4–10.2) patients in Groups P and C, respectively, with no significant between-group difference. The relative risk was 1.01 (95%CI: 0.95–1.07). The lesser curvature or anterior wall was the bleeding site in all 6 patients who experienced postoperative bleeding in Group P. In multivariate analysis, the odds ratios for resection diameter ≥ 50 mm and oral anticoagulant use were 6.63 (95%CI: 2.52–14.47; P = 0.0001) and 4.04 (1.26–0.69; P = 0.0164), respectively. The adjusted odds ratio of post-ESD bleeding and PuraStat was 1.28 (95%CI: 0.28–2.15).

CONCLUSION

PuraStat application is not associated with post-ESD bleeding. However, the study suggests that gravitational forces may affect the effectiveness of applied PuraStat.

Efficacy of hemostatic gel for perioperative bleeding and prevention of delayed bleeding of cold snare polypectomy under anticoagulant

Background and Aim

A hemostatic gel, PuraStat (3-D Matrix, Tokyo, Japan), is used for various gastrointestinal hemostasis. In this study, we analyzed the efficacy of PuraStat for perioperative bleeding (POB) and prevention of delayed bleeding (DB) to colorectal cold snare polypectomy (CSP) with continuous anticoagulant.

Methods

This was a single-center, retrospective study. Subjects were lesions of 2-9 mm under continuous anticoagulant from 2021 to 2023 and treated with PuraStat for POB. The definition of POB was bleeding which did not stop spontaneously by 1.0-1.5 min after resection and needed hemostasis. Successful hemostasis was defined as cessation of bleeding within 1.0-1.5 min after spraying PuraStat and the rate of it and risk factors of POB were analyzed. For comparison, cases receiving previous CSP without PuraStat were extracted from all cases with CSP (2018-2021), and POB and DB rate (DBR) were analyzed after propensity score matching.

Results

One hundred twenty-two lesions (91: direct oral anticoagulant (DOAC), 31: warfarin) with anticoagulant were analyzed and the rate of successful hemostasis with PuraStat was 92.6% (DOAC/warfarin: 93.4%/80.6%, P = 0.01). The rate of DB was 0.0%. Multivariate analysis showed that significant risk factors about unsuccessful hemostasis for POB with PuraStat were lesion size 8-9 mm (P < 0.01), warfarin (P = 0.01), and combination of antiplatelet (P = 0.01). Regarding the comparison about CSP with/without PuraStat, the clipping rate and DBR were 8.5%/94.9% (P < 0.01) and 0%/1.7% (P = 1.0).

Conclusion

The effects of PuraStat for POB and DB in colorectal CSP with continuous anticoagulant were acceptable.

New Alternative? Self-Assembling Peptide in Gastrointestinal Bleeding: A Systematic Review and Meta-Analysis

BACKGROUND

Gastrointestinal bleeding (GIB) is a common and potentially fatal condition with all-cause mortality ranging from 3 to 10%. Endoscopic therapy traditionally involves mechanical, thermal, and injection therapies. Recently, self-assembling peptide (SAP) has become increasingly available in the United States. When applied to an affected area, this gel forms an extracellular matrix-type structure allowing for hemostasis. This is the first systematic review and meta-analysis to assess the safety and efficacy of this modality in GIB.

METHODS

We performed a comprehensive literature search of major databases from inception to Nov 2022. The primary outcomes assessed were the success of hemostasis, rebleeding rates, and adverse events. The secondary outcomes assessed were successful hemostasis with monotherapy with SAP and combined therapy, which may include mechanical, injection, and thermal therapies. Pooled estimates were calculated using random-effects models with a 95% confidence interval (CI).

RESULTS

The analysis included 7 studies with 427 patients. 34% of the patients were on anticoagulation or antiplatelet agents. SAP application was technically successful in all patients. The calculated pooled rate of successful hemostasis was 93.1% (95% confidence interval (CI) 84.7-97.0, I2 = 73.6), and rebleeding rates were 8.9% (95% CI 5.3-14.4, I2 = 55.8). The pooled rates of hemostasis with SAP monotherapy and combined therapy were similar. No adverse events were noted related to SAP.

CONCLUSION

SAP appears to be a safe and effective treatment modality for patients with GIB. This modality provides an added advantage of improved visualization over the novel spray-based modalities. Further, prospective, or randomized controlled trials are needed to validate our findings.

Short Peptide Nanofiber Biomaterials Ameliorate Local Hemostatic Capacity of Surgical Materials and Intraoperative Hemostatic Applications in Clinics

Short designer self-assembling peptide (dSAP) biomaterials are a new addition to the hemostat group. It may provide a diverse and robust toolbox for surgeons to integrate wound microenvironment with much safer and stronger hemostatic capacity than conventional materials and hemostatic agents. Especially in noncompressible torso hemorrhage (NCTH), diffuse mucosal surface bleeding, and internal medical bleeding (IMB), with respect to the optimal hemostatic formulation, dSAP biomaterials are the ingenious nanofiber alternatives to make bioactive neural scaffold, nasal packing, large mucosal surface coverage in gastrointestinal surgery (esophagus, gastric lesion, duodenum, and lower digestive tract), epicardiac cell-delivery carrier, transparent matrix barrier, and so on. Herein, in multiple surgical specialties, dSAP-biomaterial-based nano-hemostats achieve safe, effective, and immediate hemostasis, facile wound healing, and potentially reduce the risks in delayed bleeding, rebleeding, post-operative bleeding, or related complications. The biosafety in vivo, bleeding indications, tissue-sealing quality, surgical feasibility, and local usability are addressed comprehensively and sequentially and pursued to develop useful surgical techniques with better hemostatic performance. Here, the state of the art and all-round advancements of nano-hemostatic approaches in surgery are provided. Relevant critical insights will inspire exciting investigations on peptide nanotechnology, next-generation biomaterials, and better promising prospects in clinics.

A novel self-assembling peptide hemostatic gel as rescue therapy for fistula bleeding after endoscopic ultrasound-guided hepaticogastrostomy

The novel synthetic self-assembling peptide PuraStat has been approved for hemostasis in endoscopic procedures. Nakahara and colleagues describe their application of PuraStat for hemostasis of refractory fistula bleeding after endoscopic ultrasound-guided hepaticogastrostomy. The effective and technically easy procedure is a useful option when hemostasis cannot be achieved by other means.

Endoscopic Resection Techniques for Duodenal and Ampullary Adenomas

Background and Aims

Duodenal polyps have a reported incidence of 0.3% to 4.6%. Sporadic, nonampullary duodenal adenomas (SNDAs) comprise less than 10% of all duodenal polyps, and ampullary adenomas are even less common. Nonetheless, the incidence continues to rise because of widespread endoscopy use. Duodenal polyps with villous features or those that are larger than 10 mm may raise concern for malignancy and require removal. We demonstrate endoscopic resection of SNDAs and ampullary adenomas using some of our preferred techniques.

Methods

The duodenum has several components that can make EMR of duodenal polyps technically challenging. Not only does the duodenum have a thin muscle layer, but it is also highly mobile and vascular, which may explain higher rates of perforation and bleeding of duodenal EMR reported in the literature compared with colon EMR. A standard adult gastroscope with a distal cap is commonly used for duodenal EMRs. Based on the location, however, side-viewing duodenoscopes or pediatric colonoscopes may be used. To prepare for EMR, a submucosal injection is performed for an adequate lift. The polyp is then resected via stiff monofilament snares and subsequently closed with hemostatic clips if feasible. The ampullectomy technique differs slightly from duodenal EMRs and carries the additional risk of pancreatitis. Submucosal injection in the ampulla may not lift well; thus, its utility is debatable. Biliary sphincterotomy should be performed, and based on endoscopist preference, the pancreatic duct (PD) guidewire can be left during resection to maintain access. After resection, a PD stent is placed to minimize pancreatitis risk.

Results

The video shows the aforementioned duodenal EMR techniques. Two clips of ampullectomy are also shown in the video.

Conclusions

A few common techniques used to perform duodenal EMR and ampullectomy are highlighted in the video. It is important to understand and manage adverse events associated with these procedures and to have established surveillance plans.

Efficacy of a novel self-assembling peptide gel for hemostasis in refractory neoplastic bleeding

Video 1Outline of how self-assembling peptide gel can be used ex vivo.

Emergency Endoscopic Hemostasis for Gastrointestinal Bleeding Using a Self-Assembling Peptide: A Case Series

Background and Objectives: A novel synthetic self-assembling peptide, PuraStat, has been introduced as a hemostatic agent. This case series aimed to evaluate the clinical efficacy of PuraStat for gastrointestinal bleeding during emergency endoscopy. Cases: Twenty-five patients with gastrointestinal bleeding who had undergone emergency endoscopy with PuraStat between August 2021 and December 2022 were retrospectively examined. Six patients were receiving antithrombotic agents, and ten patients with refractory gastrointestinal bleeding had undergone at least one endoscopic hemostatic procedure. The breakdown of bleeding was gastroduodenal ulcer/erosion in 12 cases, bleeding after gastroduodenal or colorectal endoscopic resection in 4 cases, rectal ulcer in 2 cases, postoperative anastomotic ulcer in 2 cases, and gastric cancer, diffuse antral vascular ectasia, small intestinal ulcer, colonic diverticular bleeding, and radiation proctitis in each case. The method of hemostasis was only PuraStat application in six cases, and hemostasis in combination with high-frequency hemostatic forceps, hemostatic clip, argon plasma coagulation, and hemostatic agents (i.e., thrombin) in the remaining cases. Rebleeding was observed in three cases. Hemostatic efficiency was observed in 23 cases (92%). Conclusions: PuraStat has the expected hemostatic effect on gastrointestinal bleeding during emergency endoscopy. The use of PuraStat should be considered in emergency endoscopic hemostasis of gastrointestinal bleeding.

Efficacy of self-assembling peptide in mitigating delayed bleeding after advanced endoscopic resection of gastrointestinal lesions: A meta-analysis

Background and study aims  Advanced endoscopic resection techniques carry a risk of delayed bleeding (DB). A novel fully synthetic self-assembling peptide (SAP) has shown promising results in mitigating this risk. In this meta-analysis, we evaluated all available data and analyzed the effectiveness of SAP in reducing DB after advanced endoscopic resection of gastrointestinal luminal lesions. Patients and methods  Electronic databases (PubMed, Embase, and Cochrane Library) from January 2010 through October 2022 were searched for publications addressing the use of SAP solution in patients undergoing advanced endoscopic resection of gastrointestinal lesions. Pooled proportions were calculated using fixed (inverse variance) and random-effects (DerSimonian-Laird) models. Results  The initial search identified 277 studies, of which 63 relevant articles were reviewed. The final analysis included data from six studies comprising 307 patients that met inclusion criteria. The pooled rate of DB was 5.73 % (95 % confidence interval [CI] = 3.42-8.59). Mean patient age was 69.40 years ± 1.82. The weighted mean size of resected lesions was 36.20 mm (95 % CI = 33.37-39.02). Endoscopic submucosal dissection was used in 72.69 % (95 % CI = 67.62-77.48), while endoscopic mucosal resection was used in 26.42 % (95 % CI = 21.69-31.44) of the procedures. Among the 307 patients, 36 % were on antithrombotic medications. No adverse events (AEs) were attributable to using SAP, with a pooled rate of 0.00 % (95 % CI = 0.00-1.49). Conclusions  SAP solution appears promising in reducing post-procedural DB after advanced endoscopic resection of high-risk gastrointestinal lesions with no reported AEs.

The Use of PuraStat® in the Management of Walled-Off Pancreatic Necrosis Drained Using Lumen-Apposing Metal Stents: A Case Series

Background and Objectives: Bleeding is one of the most feared and frequent adverse events in the case of EUS-guided drainage of WOPN using lumen-apposing metal stents (LAMSs) and of direct endoscopic necrosectomy (DEN). When it occurs, its management is still controversial. In the last few years, PuraStat, a novel hemostatic peptide gel has been introduced, expanding the toolbox of the endoscopic hemostatic agents. The aim of this case series was to evaluate the safety and efficacy of PuraStat in preventing and controlling bleeding of WOPN drainage using LAMSs. Materials and Methods: This is a multicenter, retrospective pilot study from three high-volume centers in Italy, including all consecutive patients treated with the novel hemostatic peptide gel after LAMSs placement for the drainage of symptomatic WOPN between 2019 and 2022. Results: A total of 10 patients were included. All patients underwent at least one session of DEN. Technical success of PuraStat was achieved in 100% of patients. In seven cases PuraStat was placed for post-DEN bleeding prevention, with one patient experiencing bleeding after DEN. In three cases, on the other hand, PuraStat was placed to manage active bleeding: two cases of oozing were successfully controlled with gel application, and a massive spurting from a retroperitoneal vessel required subsequent angiography. No re-bleeding occurred. No PuraStat-related adverse events were reported. Conclusions: This novel peptide gel could represent a promising hemostatic device, both in preventing and managing active bleeding after EUS-guided drainage of WON. Further prospective studies are needed to confirm its efficacy.

Endoscopic submucosal dissection techniques and technology: European Society of Gastrointestinal Endoscopy (ESGE) Technical Review

ESGE suggests conventional endoscopic submucosal dissection (ESD; marking and mucosal incision followed by circumferential incision and stepwise submucosal dissection) for most esophageal and gastric lesions. ESGE suggests tunneling ESD for esophageal lesions involving more than two-thirds of the esophageal circumference. ESGE recommends the pocket-creation method for colorectal ESD, at least if traction devices are not used. The use of dedicated ESD knives with size adequate to the location/thickness of the gastrointestinal wall is recommended. It is suggested that isotonic saline or viscous solutions can be used for submucosal injection. ESGE recommends traction methods in esophageal and colorectal ESD and in selected gastric lesions. After gastric ESD, coagulation of visible vessels is recommended, and post-procedural high dose proton pump inhibitor (PPI) (or vonoprazan). ESGE recommends against routine closure of the ESD defect, except in duodenal ESD. ESGE recommends corticosteroids after resection of  > 50 % of the esophageal circumference. The use of carbon dioxide when performing ESD is recommended. ESGE recommends against the performance of second-look endoscopy after ESD. ESGE recommends endoscopy/colonoscopy in the case of significant bleeding (hemodynamic instability, drop in hemoglobin > 2 g/dL, severe ongoing bleeding) to perform endoscopic hemostasis with thermal methods or clipping; hemostatic powders represent rescue therapies. ESGE recommends closure of immediate perforations with clips (through-the-scope or cap-mounted, depending on the size and shape of the perforation), as soon as possible but ideally after securing a good plane for further dissection.

Multifunctional Self-Assembled Peptide Hydrogels for Biomedical Applications

Self-assembly is a growth mechanism in nature to apply local interactions forming a minimum energy structure. Currently, self-assembled materials are considered for biomedical applications due to their pleasant features, including scalability, versatility, simplicity, and inexpensiveness. Self-assembled peptides can be applied to design and fabricate different structures, such as micelles, hydrogels, and vesicles, by diverse physical interactions between specific building blocks. Among them, bioactivity, biocompatibility, and biodegradability of peptide hydrogels have introduced them as versatile platforms in biomedical applications, such as drug delivery, tissue engineering, biosensing, and treating different diseases. Moreover, peptides are capable of mimicking the microenvironment of natural tissues and responding to internal and external stimuli for triggered drug release. In the current review, the unique characteristics of peptide hydrogels and recent advances in their design, fabrication, as well as chemical, physical, and biological properties are presented. Additionally, recent developments of these biomaterials are discussed with a particular focus on their biomedical applications in targeted drug delivery and gene delivery, stem cell therapy, cancer therapy and immune regulation, bioimaging, and regenerative medicine.

Efficacy and Safety of a Novel Hemostatic Peptide Solution During Endoscopic Submucosal Dissection: A Multicenter Randomized Controlled Trial

INTRODUCTION

To compare the effectiveness of the novel hemostatic peptide, TDM-621, with that of conventional hemostatic methods in treating intraoperative blood oozing during endoscopic submucosal dissection (ESD).

METHODS

This multicenter, open-label, randomized controlled trial involved 227 patients with gastric and rectal epithelial tumors in whom ESD was indicated. Patients in whom the source of blood oozing was difficult to identify with waterjet washing during the procedure and required hemostasis with hemostatic forceps were randomly assigned to the TDM-621 and control groups. The TDM-621 group (in which hemostasis was achieved with TDM-621, followed by coagulation hemostasis with hemostatic forceps, as needed) was compared with the control group (in which hemostasis was achieved with hemostatic forceps). The primary end point was the mean number of coagulations with hemostatic forceps, determined by a blinded independent review committee. The secondary end points were the rate of achievement of hemostasis with only TDM-621, the dosage of TDM-621, and adverse events in the TDM-621 group.

RESULTS

The mean number of coagulations with hemostatic forceps was significantly reduced in the TDM-621 group (1.0 ± 1.4) compared with that in the control group (4.9 ± 5.2) ( P < 0.001). The rate of hemostasis achievement with only TDM-621 was 62.2%; the mean dosage of TDM-621 was 1.75 ± 2.14 mL. The rates of grade ≥3 adverse events were 6.2% and 5.0% in the TDM-621 and control groups, respectively.

DISCUSSION

TDM-621 is a useful, easily operable hemostatic peptide for treatment of blood oozing during gastric and rectal ESD, with no serious safety concerns.

Endoscopic Management Using Novel Haemostatic Agents for Immediate Bleeding during Endoscopic Retrograde Cholangio-Pancreatography

Bleeding after endoscopic sphincterotomy (ES) remains as a major challenge during ERCP procedure. Standard endoscopic haemostatic procedures have demonstrated good performance for bleeding control. Novel endoscopic haemostatic agents have also been widely used in gastrointestinal bleeding management. Regardless, there is still a paucity of high-quality evidence evaluating the practicality of these agents in ERCP. This case series study was performed on the patients who underwent ERCP procedure in a tertiary referral private hospital within 2 years period. Post-ES immediate bleeding is defined as the onset of bleeding at the time of sphincterotomy. Treatment groups for post-ES bleeding are divided into (1) standard haemostatic methods and (2) novel haemostatic agents. There were 40 patients who received standard haemostatic treatment and 60 patients who received novel haemostatic agents. Initial haemostasis was achieved in all patients. Two patients who received standard haemostatic treatment had rebleeding. Meanwhile, no patients in novel haemostatic treatment group had rebleeding. In conclusion, novel haemostatic agent can be considered as an easy and practical method in daily practice, especially when an ERCP procedure is performed. Further studies with larger sample size which, if possible, can also include a cost-effectiveness analysis are still required to implement these agents as a standard procedure in clinical practice. (This abstract has been presented at the American College of Gastroenterology meeting October 2021).

Management of Adverse Events of Submucosal Endoscopy

The risk-benefit profile of submucosal endoscopic procedures is generally favorable but there exist unique considerations regarding the recognition, treatment, and prevention of submucosal endoscopic complications. Bleeding during the procedure can be managed with knife electrocautery, tamponade by injection of additional submucosal agent, or hemostatic forceps, depending on the location and degree of bleeding. Delayed bleeding should be managed with repeat endoscopy. Potential means to reduce the risk of delayed bleeding include anticipatory coagulation of visible vessels in the dissection ulcer base, applied hemostatic chemicals, snares, clips, and sheets of cultured cells.

Noninvasive endoscopic hemostasis technique for post-papillectomy bleeding using a novel self-assembling peptide (with video)

Although a novel hemostatic agent has been used for endoscopic mucosal resection in submucosal dissection, there are few case reports of its use in pancreato-biliary endoscopic procedures. We describe a case of post-endoscopic papillectomy bleeding in which endoscopic hemostasis was achieved using a novel hemostatic agent.

Comparison of Endoscopic Hemostasis for Endoscopic Sphincterotomy Bleeding between a Novel Self-Assembling Peptide and Conventional Technique

Introduction: Recently, a novel self-assembling peptide hemostatic gel has become available in Japan. However, the safety and efficacy of this novel self-assembling peptide hemostatic gel remain unclear for bleeding after EST. The aim of this study was to evaluate the safety and efficacy of a novel self-assembling peptide hemostatic gel for bleeding after EST, and to perform a comparison to a conventional endoscopic hemostasis technique. Method: This retrospective study was carried out between January 2019 and October 2022. Patients who developed bleeding associated with EST were enrolled. The patients were divided into two groups based on the hemostasis technique used: a conventional hemostasis technique (Group A) or a novel self-assembling peptide hemostatic gel hemostasis technique (Group B). Result: A total of 62 patients (Group A, n = 36; Group B, n = 26) were included. Endoscopic hemostasis was initially obtained in 72.2% (26/32) of patients in Group A and in 88.4% (23/26) of patients in Group B, which was not significantly different (p = 0.1320). However, the procedure time was significantly shorter in Group B (mean, 9.38 min) compared with Group A (mean, 15.4 min) (p = 0.0103). There were no significant differences in the severity of bleeding between the two groups (p = 0.4530). Post-EST bleeding was observed in six patients (Group A, n = 4; Group B, n = 2). Adverse events were more frequently observed in Group A (n = 12) than in Group B (n = 1) (p = 0.0457). Conclusions: PuraStat application for EST bleeding might be safe and effective, and is comparable to the conventional endoscopic hemostasis technique, although further prospective randomized trials are needed.

Effectiveness and safety of a newly designed self-assembling gel in the treatment of endoscopic submucosal dissection-induced gastric ulcer: A multicenter randomized controlled trial

Objectives: To evaluate the effectiveness and safety of a newly designed self-assembling gel in treating ESD-induced gastric ulcers in patients.

Methods: This open-label, multicenter, randomized controlled trial enrolled patients who underwent ESD between September 2020 and May 2021. Patients were randomized (1:1) to receive the gel (applied to cover the entire ulcer bed under endoscopic guidance immediately after ESD; gel group) or not (control group). The primary outcome was the ulcer healing rate at 28 days. And the secondary outcomes were the delayed bleeding, changes in the ulcer stage, and adverse events.

Results: Finally, 125 patients (mean age, 63.7 years; 70 [56.0%] males) were enrolled. The ulcer healing rate was higher in the gel group than in the control group at 28 days (96.9 ± 4.1% vs. 94.7 ± 5.0%; p = 0.001). The ulcer reduction rate at 28 days differed significantly (p &lt; 0.001) between ulcers with majority gel coverage (99.8%), ulcers with minority gel coverage (96.2%), and ulcers with no gel coverage (98.0%). Delayed bleeding was found in 1/63 gel-treated patients (1.6%) versus 5/62 controls (8.1%). A1-stage ulcers were found in 16/63 patients in the gel group versus 44/62 patients in the control group (25.4% vs. 71.0%, p &lt; 0.001) at 3–5 days.

Conclusion: The newly developed self-assembling gel was safe and effective in accelerating gastric ulcer healing in patients after ESD.

Clinical Trial Registration: UMIN Clinical Trials Registry System (registration number, ChiCTR2100052935).

Bulking agents in gastrointestinal endoscopy: present applications and future advances

PURPOSE OF REVIEW

Bulking agents are inert materials injected into an organ to affect the physical properties of the organ for a therapeutic purpose. Various agents have been developed to aid in the treatment of diseases like gastroesophageal reflux disease (GERD), fecal incontinence, obesity, malignancy, hemostasis, and tissue dissection. Here, we review the state of the art in bulking agents in gastrointestinal endoscopy, past failures, current limitations, and where we see the field heading in the future.

RECENT FINDINGS

Though bulking agents have been trialed for various different gastrointestinal diseases, there are currently limited uses in gastrointestinal endoscopy. Though various agents have been trialed for GERD, numerous complications and adverse events have limited its current use. However, for the treatment of fecal incontinence endoscopic bulking agent therapy is a reasonable option. Though in early stages of exploration, bulking agent therapy for enteric protection from radiotherapy may be a promising tool to improve treatment of pancreatic cancer. Bulking agents for tissue dissection have substantially improved lifting agents and complex polyp removal. Bulking agent therapy has not really been explored for endoscopic bariatric therapy or hemostasis but may be a fruitful area for exploration in the future.

SUMMARY

Bulking agent therapy has been trialed for various gastrointestinal diseases with mixed success. There is currently a therapeutic roll in the endoscopic management of fecal incontinence and tissue dissection. A future role in the treatment of GERD, obesity, malignancy, and hemostasis seem feasible.

Prophylactic Clipping to Prevent Delayed Bleeding and Perforation After Endoscopic Submucosal Dissection and Endoscopic Mucosal Resection: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

To help prevent delayed adverse events after endoscopic surgery, endoscopists often place clips at the site. This meta-analysis aimed to assess the efficacy and safety of prophylactic clipping in the prevention of delayed bleeding and perforation after endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR).

METHODS

Multiple databases were searched from the inception dates to April 2021. And we included all relevant studies. Pooled odds ratio comparing the prophylactic clipped group versus nonprophylactic clipped group were calculated using the random effects model.

RESULTS

Twenty-seven articles fulfilled the inclusion criteria, with a total size of 8693 participants. There was statistically significant difference in prophylactic clipping versus no prophylactic clipping for delayed bleeding and perforation found in all studies (odds ratio: 0.35, 95% confidence interval: 0.25-0.49, P <0.01; odds ratio: 0.42, 95% confidence interval: 0.21-0.83, P <0.05; respectively). Besides, statistically significant difference was also found in subgroup analyses based on patients with lesions larger than 20 mm. Prophylactic clipping was more protective for duodenal delayed adverse events than colorectum. The use of clip closure was more protective to ESD-related delayed adverse events than EMR.

CONCLUSIONS

Prophylactic clipping after ESD and EMR was beneficial in preventing delayed bleeding and perforation.

Hemostatic powders for gastrointestinal bleeding: a review of old, new, and emerging agents in a rapidly advancing field

Background and study aims  Hemostatic powders are increasingly used to address limitations in conventional endoscopic techniques for gastrointestinal bleeding. Various agents exist with different compositions, characteristics, efficacy, and adverse events (AEs). We sought to review existing hemostatic powders, from preclinical to established agents. Methods  A literature review on hemostatic powders for gastrointestinal bleeding was undertaken through a MEDLINE search from 2000-2021 and hand searching of articles. Relevant literature was critically appraised and reviewed for mechanism of action, hemostasis and rebleeding rate, factors associated with hemostatic failure, and AEs. Results  The most established agents are TC-325 (Hemospray), EndoClot, and Ankaferd Blood Stopper (ABS). These agents have been successfully applied to a variety of upper and lower gastrointestinal bleeding etiologies, in the form of primary, combination, salvage, and bridging therapy. Few AEs have been reported, including visceral perforation, venous embolism, and self-limited abdominal pain. Newer agents include CEGP-003 and UI-EWD, which have shown results similar to those for the older agents in initial clinical studies. All aforementioned powders have high immediate hemostasis rates, particularly in scenarios not amenable to conventional endoscopic methods, but are limited by significant rates of rebleeding. Other treatments include TDM-621 (PuraStat) consisting of a liquid hemostatic agent newly applied to endoscopy and self-propelling thrombin powder (CounterFlow Powder), a preclinical but promising agent. Conclusions  Rapid development of hemostatic powders and growing clinical expertise has established these agents as a valuable strategy in gastrointestinal bleeding. Further research will continue to refine the efficacy and applicability of these agents.

Supramolecular Peptide Nanofiber Hydrogels for Bone Tissue Engineering: From Multihierarchical Fabrications to Comprehensive Applications

Bone tissue engineering is becoming an ideal strategy to replace autologous bone grafts for surgical bone repair, but the multihierarchical complexity of natural bone is still difficult to emulate due to the lack of suitable biomaterials. Supramolecular peptide nanofiber hydrogels (SPNHs) are emerging biomaterials because of their inherent biocompatibility, satisfied biodegradability, high purity, facile functionalization, and tunable mechanical properties. This review initially focuses on the multihierarchical fabrications by SPNHs to emulate natural bony extracellular matrix. Structurally, supramolecular peptides based on distinctive building blocks can assemble into nanofiber hydrogels, which can be used as nanomorphology-mimetic scaffolds for tissue engineering. Biochemically, bioactive motifs and bioactive factors can be covalently tethered or physically absorbed to SPNHs to endow various functions depending on physiological and pharmacological requirements. Mechanically, four strategies are summarized to optimize the biophysical microenvironment of SPNHs for bone regeneration. Furthermore, comprehensive applications about SPNHs for bone tissue engineering are reviewed. The biomaterials can be directly used in the form of injectable hydrogels or composite nanoscaffolds, or they can be used to construct engineered bone grafts by bioprinting or bioreactors. Finally, continuing challenges and outlook are discussed.

Delayed Bleeding After Endoscopic Resection of Colorectal Polyps: Identifying High-Risk Patients

Delayed post-polypectomy bleeding (DPPB) is a potentially severe complication of therapeutic colonoscopy which can result in hospital readmission and re-intervention. Over the last decade, rates of DPPB reported in the literature have fallen from over 2% to 0.3–1.2%, largely due to improvements in resection technique, a shift towards cold snare polypectomy, better training, adherence to guidelines on periprocedural antithrombotic management, and the use of antithrombotics with more favourable bleeding profiles. However, as the complexity of polypectomy undertaken worldwide increases, so does the importance of identifying patients at increased risk of DPPB. Risk factors can be categorised according to patient, polyp and personnel related factors, and their integration together to provide an individualised risk score is an evolving field. Strategies to reduce DPPB include safe practices relevant to all patients undergoing colonoscopy, as well as specific considerations for patients identified to be high risk. This narrative review sets out an evidence-based summary of factors that contribute to the risk of DPPB before discussing pragmatic interventions to mitigate their risk and improve patient safety.

PuraStat RADA16 Self-Assembling Peptide Reduces Postoperative Abdominal Adhesion Formation in a Rabbit Cecal Sidewall Injury Model

Objective: To evaluate the effect of PuraStat (2.5% RADA16) administration on postoperative abdominal adhesion formation in an in vivo model.

Methods: Anesthetized New Zealand white rabbits underwent cecal sidewall abrasion surgery in which the cecal serosa and juxtaposed parietal peritoneum were abraded after access through an abdominal midline incision. Eight animals were randomized to receive PuraStat administration at the interface of the injured tissues before incision closure, and five animals served as untreated controls. Treated animals received 3–12 ml PuraStat solution per lesion. Animals were sacrificed 14 days after surgery and examined for adhesion formation at the wound site.

Results: At study terminus, adhesions were identified in 90% (9/10) of abraded cecum/peritoneal wound sites in untreated controls versus 25% (4/16) of PuraStat-treated sites (p = 0.004). Mean ± SD Total Adhesion Score (average of the values for extent + strength of the adhesion in both defects per animal; maximum score = 14 points) was significantly 76% lower in PuraStat-treated animals (2.0 ± 3.0 points) compared to untreated controls (8.2 ± 1.9 points) (p = 0.029). Mean adhesion coverage area of wound sites was 79% lower in PuraStat-treated animals than controls (p < 0.001), and mean adhesion durability was 72% lower in PuraStat-treated animals versus controls (p = 0.005). Remnant hydrogel was observed at the wound sites of 75% of treated animals at postoperative Day 14.

Conclusion: PuraStat treatment has a positive protective effect in the cecal sidewall injury model, and significantly reduces abdominal adhesion formation at the interface of the injured cecum and overlying peritoneal sidewall defect.

Efficacy and histopathological effects of self-assembling peptides RADA16 and IEIK13 in neurosurgical hemostasis

There is a continued need for effective hemostatic agents that are safe for neurosurgical use. Self-assembling peptide hydrogels have been suggested as novel hemostatic agents. They offer some advantages for neurosurgical hemostasis (e.g., transparency), but their efficacy and safety for neurosurgery has not been established. In this paper, the efficacy and safety of two self-assembling peptides, RADA16 and IEIK13, are explored for hemostasis of oozing bleeding on the rat cerebral cortex (n=56). Chronic safety was evaluated by neuropathological evaluation at one, four, and twelve weeks after craniotomy (n=32). An inactive control and oxidized cellulose served as comparators. Mean time-to-hemostasis was significantly shorter for RADA16 and IEIK13 compared to controls, while safety evaluation yielded similar results. Histopathological response consisted primarily of macrophage infiltration at the lesion site in all groups. This study confirms the hemostatic potential and safety of RADA16 and IEIK13 for hemostasis in the rat brain.

"PP-type" self-assembling peptides with superior rheological properties

The ionic-complementary self-assembling peptides discovered by Zhang Shuguang have solution-to-gel (sol-gel) transition capacity and one such peptide RADA16 has been commercialized into hemostatic agents. However, their sol-gel transition ability was not obvious because the peptide aqueous solution with a concentration greater than 1% w/v appeared to be thick and viscous. The current report describes PP-type self-assembling peptides. In addition to the ionic-complementary sequence, they have prolines at both ends of the sequence. This feature has led to better solubility, lower viscosity of the peptide solution, and simplified synthesis and purification processes while maintaining the great gelling performance of the ionic-complementary peptides. The PP-type peptides self-assembled into a well-organized nanofiber scaffold as shown by TEM. Among the PP-type peptides, the PRVDP9 sequence peptide was tested as a hemostatic agent and a mucosal elevating agent. The results were comparable to the classic RADA16. The PP-type self-assembling peptides have superior sol-gel transition ability. Therefore, it is predicted that they will be more suitable to be transported through catheters or endoscopes and have higher commercialization potential as compared with the classic self-assembling peptide sequences.

Self-assembling peptide haemostatic gel reduces incidence of pelvic collection after total mesorectal excision: Prospective cohort study

BACKGROUND

Pelvic surgery has the potential to leave behind a large raw surface, which can bleed and ooze postoperatively. The adoption of precision surgical approach for rectal cancers has led to reduction in blood loss. We aimed to assess 1) the feasibility and 2) the safety of using a self-assembling peptide (SAP) haemostatic agent (PuraStat®) after rectal cancer surgery to reduce the incidence of pelvic collections.

MATERIALS AND METHODS

This prospective cohort pilot study compared the results of 25 consecutive cases of total mesorectal excision (TME) with use of 5-10 ml of SAP, and 25 consecutive cases without PuraStat® application (CON, control group). The groups were compared for complications (Clavien-Dindo grade III and IV classification), postoperative drain output and length of hospital stay (LOS). Statistical analysis was carried out using paired samples T test and Fisher's exact test.

RESULTS

Fifty patients (SAP = 25, CON = 25) were enrolled into this study. Mean drain outputs (ml) on day 1, day 2 and day 3 were 60 ± 18, 89 ± 42 and 64 ± 45 in SAP group, and 102 ± 31, 95 ± 52, 66 ± 37 in CON group. This was significantly better for SAP group in day one after surgery. The mean LOS was shorter in SAP group (5.7 versus 7.4 days in CON, p 0.04). Clavien-Dindo III & IV complications were seen in two and five cases respectively (p 0.18). R0 resection rate (p 0.32) and lymph node harvest (p 0.13) were similar in both groups. There were no complications seen in relation to the application of the SAP.

CONCLUSIONS

These initial data suggest that SAP is a safe product, and feasible to apply in the pelvis after TME surgery. It appears to shorten the LOS and reduce the postoperative drain output and may reduce the incidence of Clavien-Dindo grade III & IV complications.

PuraStat in gastrointestinal bleeding: results of a prospective multicentre observational pilot study

Background

A recently developed haemostatic peptide gel for endoscopic application has been introduced to improve the management of gastrointestinal bleeding. The aim of this pilot study was to evaluate the feasibility, safety, efficacy and indication profiles of PuraStat in a clinical setting.

Methods

In this prospective observational multicentre pilot study, patients with acute non-variceal gastrointestinal bleeding (upper and lower) were included. Primary and secondary application of PuraStat was evaluated. Haemoglobin, prothrombin time, platelets and transfusion behaviour were documented before and after haemostasis. The efficacy of PuraStat was assessed during the procedure, at 3 days and 1 week after application.

Results

111 patients with acute gastrointestinal bleeding were recruited into the study. 70 percent (78/111) of the patients had upper gastrointestinal bleeding and 30% (33/111) had lower gastrointestinal bleeding. After primary application of PuraStat, initial haemostatic success was achieved in 94% of patients (74/79, 95% CI 88–99%), and in 75% of the patients when used as a secondary haemostatic product, following failure of established techniques (24/32, 95% CI 59–91%). The therapeutic success rates (absence of rebleeding) after 3 and 7 days were 91% and 87% after primary use, and 87% and 81% in all study patients. Overall rebleeding rate at 30 day follow-up was 16% (18/111). In the 5 patients who finally required surgery (4.5%), PuraStat allowed temporary haemostasis and stabilisation.

Conclusions

PuraStat expanded the therapeutic toolbox available for an effective treatment of gastrointestinal bleeding sources. It could be safely applied and administered without complications as a primary or secondary therapy. PuraStat may additionally serve as a bridge to surgery in order to achieve temporary haemostasis in case of refractory severe bleeding, possibly playing a role in preventing immediate emergency surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00464-021-08589-6.

Clinical Use of the Self-Assembling Peptide RADA16: A Review of Current and Future Trends in Biomedicine

RADA16 is a synthetic peptide that exists as a viscous solution in an acidic formulation. In an acidic aqueous environment, the peptides spontaneously self-assemble into β-sheet nanofibers. Upon exposure and buffering of RADA16 solution to the physiological pH of biological fluids such as blood, interstitial fluid and lymph, the nanofibers begin physically crosslinking within seconds into a stable interwoven transparent hydrogel 3-D matrix. The RADA16 nanofiber hydrogel structure closely resembles the 3-dimensional architecture of native extracellular matrices. These properties make RADA16 formulations ideal topical hemostatic agents for controlling bleeding during surgery and to prevent post-operative rebleeding. A commercial RADA16 formulation is currently used for hemostasis in cardiovascular, gastrointestinal, and otorhinolaryngological surgical procedures, and studies are underway to investigate its use in wound healing and adhesion reduction. Straightforward application of viscous RADA16 into areas that are not easily accessible circumvents technical challenges in difficult-to-reach bleeding sites. The transparent hydrogel allows clear visualization of the surgical field and facilitates suture line assessment and revision. The shear-thinning and thixotropic properties of RADA16 allow its easy application through a narrow nozzle such as an endoscopic catheter. RADA16 hydrogels can fill tissue voids and do not swell so can be safely used in close proximity to pressure-sensitive tissues and in enclosed non-expandable regions. By definition, the synthetic peptide avoids potential microbiological contamination and immune responses that may occur with animal-, plant-, or mineral-derived topical hemostats. In vitro experiments, animal studies, and recent clinical experiences suggest that RADA16 nanofibrous hydrogels can act as surrogate extracellular matrices that support cellular behavior and interactions essential for wound healing and for tissue regenerative applications. In the future, the unique nature of RADA16 may also allow us to use it as a depot for precisely regulated drug and biopharmaceutical delivery.

Prevention of late complications with coverage agents in endoscopic resection of colorectal lesions: Current landscape in gastrointestinal endoscopy

Endoscopic removal of large (≥ 20 mm) non-pedunculated colorectal lesions (LNPCLs) may result in major adverse events, such as delayed bleeding (DB) and delayed perforation (DP), despite closure of the mucosal defects with clips. Topical application of a coverage agent refers to the creation of a shield with a biocompatible medical device (tissue or hydrogel) with proven bioactive properties. Coverage of the eschar after endoscopic resection provides shielding protection to prevent delayed complications. The aim of the present review was to systematically collect and review the currently available literature regarding the prevention of DB and DP with coverage agents after endoscopic mucosal resection or endoscopic submucosal dissection of LNPCLs.