Anti-adhesive effects of a newly developed two-layered gelatin sheet in dogs

Multilayered Shape-Morphing Scaffolds with a Hierarchical Structure for Uterine Tissue Regeneration

Owing to dysfunction of the uterus, millions of couples around the world suffer from infertility. Different from conventional treatments, tissue engineering provides a new and promising approach to deal with difficult problems such as human tissue or organ failure. Adopting scaffold-based tissue engineering, three-dimensional (3D) porous scaffolds in combination with stem cells and appropriate biomolecules may be constructed for uterine tissue regeneration. In this study, a hierarchical tissue engineering scaffold, which mimicked the uterine tissue structure and functions, was designed, and the biomimicking scaffolds were then successfully fabricated using solvent casting, layer-by-layer assembly, and 3D bioprinting techniques. For the multilayered, hierarchical structured scaffolds, poly(l-lactide-co-trimethylene carbonate) (PLLA-co-TMC, "PLATMC" in short) and poly(lactic acid-co-glycolic acid) (PLGA) blends were first used to fabricate the shape-morphing layer of the scaffolds, which was to mimic the function of myometrium in uterine tissue. The PLATMC/PLGA polymer blend scaffolds were highly stretchable. Subsequently, after etching of the PLATMC/PLGA surface and employing estradiol (E2), polydopamine (PDA), and hyaluronic acid (HA), PDA@E2/HA multilayer films were formed on PLATMC/PLGA scaffolds to build an intelligent delivery platform to enable controlled and sustained release of E2. The PDA@E2/HA multilayer films also improved the biological performance of the scaffold. Finally, a layer of bone marrow-derived mesenchymal stem cell (BMSC)-laden hydrogel [which was a blend of gelatin methacryloyl (GelMA) and gelatin (Gel)] was 3D printed on the PDA@E2/HA multilayer films of the scaffold, thereby completing the construction of the hierarchical scaffold. BMSCs in the GelMA/Gel hydrogel layer exhibited excellent cell viability and could spread and be released eventually upon biodegradation of the GelMA/Gel hydrogel. It was shown that the hierarchically structured scaffolds could evolve from the initial flat shape into the tubular structure completely in an aqueous environment at 37 °C, fulfilling the requirement for curved scaffolds for uterine tissue engineering. The biomimicking scaffolds with a hierarchical structure and curved shape, high stretchability, and controlled and sustained E2 release appear to be very promising for uterine tissue regeneration.

Clinical feasibility of absorbable gelatin film adhesion barrier (GM142 "TENALEAF®") in gynecological laparoscopic surgery: Safety assessment for first-in-human use and surgical video

AIM

To evaluate the safety and operability of the GM142 (TENALEAF®, Medical Division, Gunze Limited, Tokyo, Japan) adhesion barrier applied in patients undergoing surgery for benign gynecologic disease.

METHODS

This multicenter open study enrolled 34 patients from November 2018 to October 2019.

RESULTS

The primary outcome was the incidence of adverse events (AE) within 12 weeks postoperatively. None of the 30 patients completing the study experienced a life-threatening AE. Thirteen patients (43.3%) suffered 30 mild or moderate AE in total. No intestinal obstruction (0/30) was observed, with the sample size justified by the AdSpray® trial (8/61 patients with AE). No gelatin-specific Immunoglobulin E (IgE) antibodies were induced in the patients. The adhesion barrier could be easily inserted (even via trocar) and positioned. After malfunctions were reported in six patients, the instructions for use were updated for trocar use.

CONCLUSION

This study showed the safety and clinical feasibility GM142 as an adhesion barrier.

Efficacy of gelatin sponge in the prevention of post-surgical intra-abdominal adhesion in a rat model

Although different products have been developed to prevent post-surgical adhesion, their efficacy remains unsatisfactory. This study aimed to evaluate the efficacy of the gelatin sponge in the prevention of post-surgical intra-abdominal adhesions in a rat model. Rats were randomly divided into sham, adhesion, and gelatin groups. All rats, except the sham group, underwent cecal abrasion to establish an adhesion model. After celiotomy, a sterile gelatin sponge was applied intra-abdominal on the abraded cecum in the gelatin group. Rats were sacrificed on day 14 post-surgery and intra-abdominal adhesions were evaluated and scored. Adhesion tissues were evaluated by histological, histochemical, and immunohistochemical analysis. Intra-abdominal adhesions were recorded in all rats of the adhesion group. Intra-abdominal application of gelatin sponge significantly (P < 0.001) reduced intra-abdominal adhesions by 91% in the gelatin group relative to the adhesion group. The histological analysis revealed a marked decrease (P < 0.001) in the inflammatory score and neovascularization in the gelatin group. The histochemical analysis found that gelatin sponge administration reduced adhesion formation and thickness of adhesion tissue. Moreover, gelatin sponge significantly (P < 0.0001) increased MMP-9 expression and decreased macrophage marker expression in adhesive tissue. This study revealed that the application of gelatin sponge markedly reduced the post-surgical intra-abdominal adhesions and suggests new guidance for using gelatin sponge as an anti-adhesive substance in clinical practice.

Prevention of Post-Operative Adhesions: A Comprehensive Review of Present and Emerging Strategies

Post-operative adhesions affect patients undergoing all types of surgeries. They are associated with serious complications, including higher risk of morbidity and mortality. Given increased hospitalization, longer operative times, and longer length of hospital stay, post-surgical adhesions also pose a great financial burden. Although our knowledge of some of the underlying mechanisms driving adhesion formation has significantly improved over the past two decades, literature has yet to fully explain the pathogenesis and etiology of post-surgical adhesions. As a result, finding an ideal preventative strategy and leveraging appropriate tissue engineering strategies has proven to be difficult. Different products have been developed and enjoyed various levels of success along the translational tissue engineering research spectrum, but their clinical translation has been limited. Herein, we comprehensively review the agents and products that have been developed to mitigate post-operative adhesion formation. We also assess emerging strategies that aid in facilitating precision and personalized medicine to improve outcomes for patients and our healthcare system.

Peritoneal adhesions: Occurrence, prevention and experimental models

Peritoneal adhesions (PA) are a postoperative syndrome with high incidence rate, which can cause chronic abdominal pain, intestinal obstruction, and female infertility. Previous studies have identified that PA are caused by a disordered feedback of blood coagulation, inflammation, and fibrinolysis. Monocytes, macrophages, fibroblasts, and mesothelial cells are involved in this process, and secreted signaling molecules, such as tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), tissue plasminogen activator (tPA), and type 1 plasminogen activator inhibitor (PAI-1), play a key role in PA development. There have been many attempts to prevent PA formation by anti-PA drugs, barriers, and other therapeutic methods, but their effectiveness has not been widely accepted. Treatment by biomaterial-based barriers is believed to be the most promising method to prevent PA formation in recent years. In this review, the pathogenesis, treatment approaches, and animal models of PA are summarized and discussed to understand the challenges faced in the biomaterial-based anti-PA treatments.

[Existing and forward-looking ways to prevent adhesions in IPOM hernia repair. A research overview]

IPOM intraperitoneal hernia repair, in comparison with other abdominal wall reconstruction methods, has a number of significant advantages. Among them are a reduction in operative time, low rate of surgical site infections, quick rehabilitation, and good cosmetic results. At the same time, one of the main constraining factors for its widespread use is the rather high frequency of adhesion formation between the implant and the abdominal organs. The first way to solve this serious problem is to improve the structure of the implant itself, and in the first place, its anti-adhesive layer. The second is the search for adjuvant tools that work in «problematic» areas, prone to adhesions formation, such as the points of implant fixation, its edges, or the areas of damage to antiadhesive layer due to a violation of the operative technique. It is desirable that they could exert their effect also in other parts of the abdominal cavity, which, despite the absence of a zone of «active» intervention, can also undergo adhesions. Based on this, the purpose of this review was to summarize modern data on the anti-adhesive activity of both composite implants and specialized membranes and liquid agents.

Biomaterials to Prevent Post-Operative Adhesion

Surgery is performed to treat various diseases. During the process, the surgical site is healed through self-healing after surgery. Post-operative or tissue adhesion caused by unnecessary contact with the surgical site occurs during the normal healing process. In addition, it has been frequently found in patients who have undergone surgery, and severe adhesion can cause chronic pain and various complications. Therefore, anti-adhesion barriers have been developed using multiple biomaterials to prevent post-operative adhesion. Typically, anti-adhesion barriers are manufactured and sold in numerous forms, such as gels, solutions, and films, but there are no products that can completely prevent post-operative adhesion. These products are generally applied over the surgical site to physically block adhesion to other sites (organs). Many studies have recently been conducted to increase the anti-adhesion effects through various strategies. This article reviews recent research trends in anti-adhesion barriers.

Anti-adhesive effects of a newly developed two-layered gelatin sheet in dogs

Aim

Adhesion after pelvic surgery causes infertility, ectopic pregnancy, and ileus or abdominal pain. The materials currently available for clinical use are insufficient. The purpose of this study was to develop an anti‐adhesive material that overcomes the limitations of conventional anti‐adhesive agents.

Methods

The adhesion prevention effects of three methods – a two‐layered sheet composed of gelatin film and gelatin sponge, Seprafilm and INTERCEED – were evaluated in 37 dogs. Anti‐adhesive effects were investigated macroscopically and microscopically in a cauterized uterus adhesion model. Cell growth on the materials in vitro using human peritoneal mesothelial cells, fibroblasts and uterine smooth muscle cells were also evaluated.

Results

The two‐layered gelatin sheet had significantly superior anti‐adhesive effects compared to the conventional materials (Seprafilm and INTERCEED). A single‐cell layer of mature mesothelium formed three weeks after surgery in the gelatin group. Peritoneum regeneration in the Seprafilm and INTERCEED groups was delayed and incomplete in the early phase. Little inflammation around the materials occurred and cell growth was significantly proliferated with the gelatin sheet.

Conclusion

The anti‐adhesive effects of a two‐layered gelatin sheet were superior to conventional agents in a cauterized canine uterus model, demonstrating early regeneration of the peritoneum, little inflammation and material endurance. The newly developed two‐layered gelatin sheet is a useful option as an anti‐adhesive agent for deeply injured and hemorrhagic sites.