A light-activated amnion wrap strengthens colonic anastomosis and reduces peri-anastomotic adhesions

Double-layer adhesives for preventing anastomotic leakage and reducing post-surgical adhesion

Preventing anastomotic leakage (AL) and postoperative adhesions after gastrointestinal surgery is crucial for ensuring a favorable surgical prognosis. However, AL prevention using tissue adhesives can unintentionally lead to undesirable adhesion formation, while anti-adhesive agents may interfere with wound healing and contribute to AL. In this study, we have developed a double-layer patch, consisting of an adhesive layer on one side, utilizing gallic acid-conjugated chitosan (CHI-G), and an anti-adhesive layer on the opposite side, employing crosslinked hyaluronic acid (cHA). These CHI-G/cHA double-layer adhesives significantly prevented AL by forming physical barriers of CHI-G and reduced post-surgical adhesion at the anastomosis sites by the anti-adhesive layers of cHA. The bursting pressure (161.1 ± 21.6 mmHg) of double-layer adhesives-applied rat intestine at postoperative day 21 was far higher than those of the control (129.4 ± 5.7 mmHg) and the commercial anti-adhesives-applied group (120.8 ± 5.2 mmHg). In addition, adhesion score of double-layer adhesives-applied rat intestine was 3.6 ± 0.3 at postoperative day 21, which was similar to that of the commercial anti-adhesives-applied group (3.6 ± 0.3) and lower than that of the control group (4.9 ± 0.5). These findings indicate that the double-layer patch (CHI-G/cHA) has the potential to effectively prevent both postoperative adhesions and anastomotic leakage, offering a promising solution for gastrointestinal surgery.

Evaluation of colonic anastomosis healing using hybrid nanosheets containing molybdenum disulfide (MOS2) scaffold of human placental amniotic membrane and polycaprolactone (PCL) in rat animal model

Anastomosis is a standard technique following different conditions such as obstruction, tumor, and trauma. Obstruction, adhesion, or anastomosis leakage can be some of its complications. To improve healing and prevent postoperative complications, we design a hybrid scaffold containing acellular human amniotic membranes and polycaprolactone-molybdenum disulfide nanosheets for colon anastomosis. The animal model of colocolonic anastomosis was performed on two groups of rats: control and scaffold. The hybrid scaffold was warped around the anastomosis site in the scaffold group. Samples from the anastomosis site were resected on the third and seventh postoperative days for histopathological and molecular assessments. Histopathologic score and burst pressure had shown significant improvement in the scaffold group. No mortality and anastomosis leakage was reported in the scaffold group. In addition, inflammatory markers were significantly decreased, while anti-inflammatory cytokines were increased in the scaffold group. The result indicates that our hybrid scaffold is a proper choice for colorectal anastomosis repair by declining postoperative complications and accelerating healing.

Laser tissue soldering of the gastrointestinal tract: A systematic review LTS of the gastrointestinal tract

Background

Laser Tissue Soldering (LTS) is a promising tissue bonding technique in which a solder is applied between the tissues and then irradiated by laser, causing it to solidify and form links with the tissue.

Methods

A comprehensive systematic review summarizing the state of research of LTS in the gastrointestinal tract.

Results

Most studies were conducted on large animal tissues, using liquid proteinaceous solder, and irradiated by a continuous wave laser at 808 nm. LTS can provide better sealing and burst pressure than conventional methods. The application of LTS on top of or in addition to sutures showed an impressive increase in burst pressures. LTS may decrease the inflammatory and foreign body reaction caused by sutures.

Conclusions

LTS has strong potential to be applied in a clinical setting in leak prevention and in closure of gastrointestinal structures as an adjunct or additional anastomotic technology, decreasing leak rates, morbidity, and mortality.

Application of amniotic membranes in reconstructive surgery of internal organs-A systematic review and meta-analysis

Amniotic membrane (AM) has great potential as a scaffold for tissue regeneration in reconstructive surgery. To date, no systematic review of the literature has been performed for the applications of AM in wound closure of internal organs. Therefore, in this systematic review and meta-analysis, we summarize the literature on the safety and efficacy of AM for the closure of internal organs. A systematic search was performed in MEDLINE-PubMed database and OVID Embase to retrieve human and controlled animal studies on wound closure of internal organs. The Cochrane Risk of Bias tool for randomized clinical trials and the SYRCLE risk of bias tool for animal studies were used. Meta-analyses (MAs) were conducted for controlled animal studies to assess efficacy of closure, mortality and complications in subjects who underwent surgical wound closure in internal organs with the application of AM. Sixty references containing 26 human experiments and 36 animal experiments were included. The MAs of the controlled animal studies showed comparable results with regard to closure, mortality and complications, and suggested improved mechanical strength and lower inflammation scores after AM application when compared to standard surgical closure techniques. This systematic review and MAs demonstrate that the application of AM to promote wound healing of internal organs appears to be safe, efficacious, and feasible.

Self-Organization Dynamics of Collagen-like Peptides Crosslinking Is Driven by Rose-Bengal-Mediated Electrostatic Bridges

The present work focuses on the computational study of the structural micro-organization of hydrogels based on collagen-like peptides (CLPs) in complex with Rose Bengal (RB). In previous studies, these hydrogels computationally and experimentally demonstrated that when RB was activated by green light, it could generate forms of stable crosslinked structures capable of regenerating biological tissues such as the skin and cornea. Here, we focus on the structural and atomic interactions of two collagen-like peptides (collagen-like peptide I (CLPI), and collagen-like peptide II, (CLPII)) in the presence and absence of RB, highlighting the acquired three-dimensional organization and going deep into the stabilization effect caused by the dye. Our results suggest that the dye could generate a ternary ground-state complex between collagen-like peptide fibers, specifically with positively charged amino acids (Lys in CLPI and Arg in CLPII), thus stabilizing ordered three-dimensional structures. The discoveries generated in this study provide the structural and atomic bases for the subsequent rational development of new synthetic peptides with improved characteristics for applications in the regeneration of biological tissues during photochemical tissue bonding therapies.

Light-activated photosealing with human amniotic membrane strengthens bowel anastomosis in a hypotensive, trauma-relevant swine model

BACKGROUND

Gastrointestinal anastomotic leakage is a dreaded complication despite advancements in surgical technique. Photochemical tissue bonding (PTB) is a method of sealing tissue surfaces utilizing photoactive dye. We evaluated if crosslinked human amniotic membrane (xHAM) photosealed over the enteroenterostomy would augment anastomotic strength in a trauma-relevant swine hemorrhagic shock model.

METHODS

Yorkshire swine (40-45 kg, n = 14) underwent midline laparotomy and sharp transection of the small intestine 120 cm proximal to the ileocecal fold. Immediately following intestinal transection, a controlled arterial bleed was performed to reach hemorrhagic shock. Intestinal repair was performed after 60 minutes and autotransfusion of the withdrawn blood was performed for resuscitation. Animals were randomized to small intestinal anastomosis by one of the following methods (seven per group): suture repair (SR), or SR with PTB augmentation. Animals were euthanized at postoperative Day 28 and burst pressure (BP) strength testing was performed on all excised specimens.

RESULTS

Mean BP for SR, PTB, and native tissue groups were 229 ± 40, 282 ± 21, and 282 ± 47 mmHg, respectively, with the SR group statistically significantly different on analysis of variance (p = 0.02). Post-hoc Tukey all-pairs comparison demonstrated a statistically significant difference in burst pressure strength between the SR only and the PTB group (p = 0.04). All specimens in SR group ruptured at the anastomosis upon burst pressure testing, while all specimens in the PTB group ruptured at least 2.5 cm from the anastomosis.

CONCLUSION

Photosealing with xHAM significantly augments the strength of small intestinal anastomosis performed in a trauma porcine model.

In vivo performance of a bilayer wrap to prevent abdominal adhesions

There is a high prevalence of intra-abdominal adhesions following bowel resection, which can result in chronic pain, bowel obstruction, and morbidity. Although commercial adhesion barriers have been widely utilized for colonic resections, these barriers do not prevent anastomotic leakage resulting from reduced healing of the anastomosis, which can result in long-term health problems. To address this limitation, we have developed an adhesive bilayer wrap with selective bioactivity to simultaneously prevent intra-abdominal adhesion formation and promote anastomotic healing. Reactive electrospinning was used to generate a crosslinked gelatin mesh to serve as a cell-instructive substrate to improve anastomotic healing. A coating of poly(ethylene glycol) (PEG) foam was applied to the bioactive mesh to generate an antifouling layer and prevent intra-abdominal adhesions. After in vitro confirmation of selective bioactivity, the composite wrap was compared after 2 weeks to a commercial product (Interceed^Ⓡ) in an in vivo rat colonic abrasion model for prevention of intra-abdominal adhesions. The composite bilayer wrap was able to prevent intra-abdominal adhesions when clinical placement was maintained. The composite bilayer wrap was further modified to include tissue adhesive properties for improved efficacy. Preliminary studies indicated that the adhesive composite bilayer wrap maintained a maximum shear strength comparable to Interceed^Ⓡ and greater than fibrin glue. Overall, this work resulted in an initial proof-of-concept device that was shown to effectively prevent intra-abdominal adhesion formation in vivo. The composite bilayer wrap studied here could lead to an improved technology for improved healing of intestinal anastomoses.

Effect of Acellular Amniotic Membrane Matrix Patch on Healing of Cut Surface After Sleeve Gastrectomy in Rats

Background: The aim of this study was to evaluate the effect of acellular amniotic membrane matrix patch on healing cut surface after sleeve gastrectomy in rats. Methods: Thirty male Wistar albino rats were divided into three groups: control (n = 10), Experiment-1 (n = 10), and Experiment-2 (n = 10) groups. Control group rats underwent only sleeve gastrectomy with primary gastrorrhaphy. Experiment-1 group rats underwent sleeve gastrectomy, primary gastrorrhaphy and covered with acellular amniotic membrane matrix patch. Experiment-2 group rats underwent sleeve gastrectomy, incomplete primary gastrorrhaphy and covered with acellular amniotic membrane matrix patch. All rats were sacrificed on the fifth postoperative day. Macroscopic findings and histopathologic alterations were evaluated and compared. Results: There was a statistically significant difference between levels of PMNs, granulation formation and vascularization, distributions of edema, type of mucosal epithelium, and fibroblastic proliferation according to groups (p < 0.05). The PMNs level in the Experiment-1 group was significantly lower than the control group (p < 0.05). In experiment groups, the level of granulation tissue, vascularization and fibroblastic proliferation was significantly higher than the control group (p < 0.05). The levels of edema and type of mucosal epithelium of the experiment groups were significantly lower than the control group (p < 0.05). Conclusion: Covering sleeve gastrectomy cut surface area with acellular amniotic membrane matrix results better healing. Moreover, acellular amniotic membrane matrix provides safe healing even in incomplete sutured area.

Rose Bengal Binding to Collagen and Tissue Photobonding

We investigated two critical aspects of rose Bengal (RB) photosensitized protein cross-linking that may underlie recently developed medical applications. Our studies focused on the binding of RB to collagen by physical interaction and the effect of this binding and certain amino acids on RB photochemistry. Molecular dynamics simulations and free-energy calculation techniques, complemented with isothermal titration calorimetry, provided insight into the binding between RB and a collagen-like peptide (CLP) at the atomic level. Electrostatic interactions dominated, which is consistent with the finding that RB bound equally well to triple helical and single chain collagen. The binding free energy ranged from -5.7 to -3 kcal/mol and was strongest near the positively charged amino groups at the N-terminus and on lysine side chains. At high RB concentration, a maximum of 16 ± 3 bound dye molecules per peptide was found, which is consistent with spectroscopic evidence for aggregated RB bound to collagen or the CLP. Within a tissue-mimetic collagen matrix, RB photobleached rapidly, probably due to electron transfer to certain protein amino acids, as was demonstrated in solutions of free RB and arginine. In the presence of arginine and low oxygen concentrations, a product absorbing at 510 nm formed, presumably due to dehalogenation after electron transfer to RB. In the collagen matrix without arginine, the dye generated singlet oxygen as well as the 510 nm product. These results provide the first evidence of the effects of a tissue-like environment on the photochemical mechanisms of rose Bengal.

Human Amniotic Membrane Is Not Suitable for the Grafting of Colon Lesions and Prevention of Adhesions in a Xenograft Rat Model

INTRODUCTION

New biological materials are needed for specific applications in reconstructive bowel surgery and for the prevention of adhesion formation. Amniotic membranes (AMs) are assumed to have a number of unique characteristics that enhance the ingrowth of the surrounding tissue. The aim of the present study was to provide proof of these qualities in a xenograft model.

MATERIALS AND METHODS

A multilayer human AM (HAM) was applied to repair defined colon wall defects in Sprague-Dawley rats (n = 18). The control group was repaired with a suture (n = 6). The animals were killed humanely at 7, 21, and 42 days after implantation. Adhesions and perioperative complications were examined. Histological and immunohistological analyses were performed to assess a number of parameters, including degradation of the HAM, inflammation, graft rejection, and smooth muscle ingrowth.

RESULTS

Two rats in the treated group died. No other severe complications were observed. Adhesion formation was more prominently visible in the HAM group ( P < .05). The initially increased inflammation in the HAM group reduced over time but remained significantly increased ( P < .05). The HAM degraded over time and a subtle transient glomerulitis could be observed.

CONCLUSION

HAMs were found to increase adhesion formation and were not suitable for bowel augmentation in the presented xenograft model.