A new bioabsorbable polymer film to prevent peritoneal adhesions validated in a post-surgical animal model

Advances in Materials with Self-Healing Properties: A Brief Review

The development of materials with self-healing capabilities has garnered considerable attention due to their potential to enhance the durability and longevity of various engineering and structural applications. In this review, we provide an overview of recent advances in materials with self-healing properties, encompassing polymers, ceramics, metals, and composites. We outline future research directions and potential applications of self-healing materials (SHMs) in diverse fields. This review aims to provide insights into the current state-of-the-art in SHM research and guide future efforts towards the development of innovative and sustainable materials with enhanced self-repair capabilities. Each material type showcases unique self-repair mechanisms tailored to address specific challenges. Furthermore, this review investigates crack healing processes, shedding light on the latest developments in this critical aspect of self-healing materials. Through an extensive exploration of these topics, this review aims to provide a comprehensive understanding of the current landscape and future directions in self-healing materials research.

Anti-adhesion multifunctional poly(lactic-co-glycolic acid)/polydimethylsiloxane wound dressing for bacterial infection monitoring and photodynamic antimicrobial therapy

Wound infection and adhesion are important factors affecting wound healing. Early detection of pathogen infection and reduction of wound-to-dressing adhesion are critical for improving wound healing. Herein, Ester-J, which can rapidly respond to lipase secreted by bacteria, was designed and synthesized. Then, Ester-J was co-spun with poly(lactic-co-glycolic acid) (PLGA) and polydimethylsiloxane (PDMS) to prepare a PP-EsJ hydrophobic anti-adhesion dressing with a contact angle of 140.7°. When the PP-EsJ membrane came into contact with the bacteria, the loaded Ester-J was hydrolyzed to Tph-TSF-OH, releasing bright cyan-blue fluorescence, thus providing a fluorescence switch for an early warning of infection. The detection limits of PP-EsJ for Pseudomonas aeruginosa and Staphylococcus aureus were 1.0 × 105 and 1.0 × 106 CFU/mL, respectively. Subsequently, Tph-TSF-OH released 1O2 through light irradiation, which rapidly killed P. aeruginosa and S. aureus, and accelerated wound healing. Compared with the control group, enhanced wound closure (up to 99.80 ± 1.10 %) was observed in mice treated with the PP-EsJ membrane. The PP-EsJ membrane not only effectively reduced the risk of external infection but also reduced adhesions to the skin during dressing changes. These characteristics make PP-EsJ membranes potentially useful for clinical treatment.

Biocompatible Nanocomposites for Postoperative Adhesion: A State-of-the-Art Review

To reduce and prevent postsurgical adhesions, a variety of scientific approaches have been suggested and applied. This includes the use of advanced therapies like tissue-engineered (TE) biomaterials and scaffolds. Currently, biocompatible antiadhesive constructs play a pivotal role in managing postoperative adhesions and several biopolymer-based products, namely hyaluronic acid (HA) and polyethylene glycol (PEG), are available on the market in different forms (e.g., sprays, hydrogels). TE polymeric constructs are usually associated with critical limitations like poor biocompatibility and mechanical properties. Hence, biocompatible nanocomposites have emerged as an advanced therapy for postoperative adhesion treatment, with hydrogels and electrospun nanofibers among the most utilized antiadhesive nanocomposites for in vitro and in vivo experiments. Recent studies have revealed that nanocomposites can be engineered to generate smart three-dimensional (3D) scaffolds that can respond to different stimuli, such as pH changes. Additionally, nanocomposites can act as multifunctional materials for the prevention of adhesions and bacterial infections, as well as tissue healing acceleration. Still, more research is needed to reveal the clinical potential of nanocomposite constructs and the possible success of nanocomposite-based products in the biomedical market.

Degradable Temperature-Sensitive Hydrogel Loaded with Heparin Effectively Prevents Post-Operative Tissue Adhesions

Tissue adhesions could occur following surgeries, and severe tissue adhesions can lead to serious complications. Medical hydrogels could be applied at surgical sites as a physical barrier to prevent tissue adhesion. For practical reasons, spreadable, degradable, and self-healable gels are highly demanded. To meet these requirements, we applied carboxymethyl chitosan (CMCS) to poloxamer-based hydrogels to generate low Poloxamer₃₃₈ (P₃₃₈) content gels displaying low viscosity at refrigerator temperature and improved mechanical strength at body temperature. Heparin, an effective adhesion inhibitor, was also added to construct P₃₃₈/CMCS-heparin composite hydrogel (PCHgel). PCHgel presents as a flowable liquid below 20 °C and could rapidly transform into gel when spread on the surface of damaged tissue due to temperature change. The introduction of CMCS enabled hydrogels to form a stable self-healable barrier at injured positions and slowly release heparin during the wound healing period before being degraded after ∼14 days. Ultimately, PCHgel significantly reduced tissue adhesion in model rats and displayed higher efficiency than P₃₃₈/CMCS gel without heparin. Its adhesion suppression mechanism was verified, and it also displayed good biosafety. Therefore, PCHgel showed good clinical transformation potential with high efficacy, good safety, and ease of use.

The Therapeutic Potential of Targeting Key Signaling Pathways as a Novel Approach to Ameliorating Post-Surgical Adhesions

BACKGROUND

Peritoneal adhesions (PA) are a common complication of abdominal operations. A growing body of evidence shows that inhibition of inflammation and fibrosis at sites of peritoneal damaging could prevent the development of intra-abdominal adhesions.

METHODS

A search of PubMed, Medline, CINAHL and Embase databases was performed using the keywords 'postsurgical adhesion', 'post-operative adhesion', 'peritoneal adhesion', 'surgery-induced adhesion' and 'abdominal adhesion'. Studies detailing the use of pharmacological and non-pharmacological agents for peritoneal adhesion prevention were identified, and their bibliographies were thoroughly reviewed to identify further related articles.

RESULTS

Several signaling pathways, such as tumor necrosis factor-alpha, tissue plasminogen activator, and type 1 plasminogen activator inhibitor, macrophages, fibroblasts, and mesothelial cells play a key part in the development of plasminogen activator. Several therapeutic approaches based on anti-PA drug barriers and traditional herbal medicines have been developed to prevent and treat adhesion formation. In recent years, the most promising method to prevent PA is treatment using biomaterial-based barriers.

CONCLUSION

In this review, we provide an overview of the pathophysiology of adhesion formation and various agents targeting different pathways, including chemical agents, herbal agents, physical barriers, and clinical trials concerning this matter.

Mechanisms of Peritoneal Mesothelial Cells in Peritoneal Adhesion

A peritoneal adhesion (PA) is a fibrotic tissue connecting the abdominal or visceral organs to the peritoneum. The formation of PAs can induce a variety of clinical diseases. However, there is currently no effective strategy for the prevention and treatment of PAs. Damage to peritoneal mesothelial cells (PMCs) is believed to cause PAs by promoting inflammation, fibrin deposition, and fibrosis formation. In the early stages of PA formation, PMCs undergo mesothelial–mesenchymal transition and have the ability to produce an extracellular matrix. The PMCs may transdifferentiate into myofibroblasts and accelerate the formation of PAs. Therefore, the aim of this review was to understand the mechanism of action of PMCs in PAs, and to offer a theoretical foundation for the treatment and prevention of PAs.

Intraperitoneal Lavage with Crocus sativus Prevents Postoperative-Induced Peritoneal Adhesion in a Rat Model: Evidence from Animal and Cellular Studies

Postoperative peritoneal adhesions are considered the major complication following abdominal surgeries. The primary clinical complications of peritoneal adhesion are intestinal obstruction, infertility, pelvic pain, and postoperative mortality. In this study, regarding the anti-inflammatory and antioxidant activities of Crocus sativus, we aimed to evaluate the effects of Crocus sativus on the prevention of postsurgical-induced peritoneal adhesion. Male Wistar-Albino rats were used to investigate the preventive effects of C. sativus extract (0.5%, 0.25% and 0.125% w/v) against postsurgical-induced peritoneal adhesion compared to pirfenidone (PFD, 7.5% w/v). We also investigated the protective effects of PFD (100 μg/ml) and C. sativus extract (100, 200, and 400 μg/ml) in TGF-β1-induced fibrotic macrophage polarization. The levels of cell proliferation and oxidative, antioxidative, inflammatory and anti-inflammatory, fibrosis, and angiogenesis biomarkers were evaluated both in vivo and in vitro models. C. sativus extract ameliorates postoperational-induced peritoneal adhesion development by attenuating oxidative stress [malondialdehyde (MDA)]; inflammatory mediators [interleukin- (IL-) 6, tumour necrosis factor- (TNF-) α, and prostaglandin E₂ (PGE₂)]; fibrosis [transforming growth factor- (TGF-) β1, IL-4, and plasminogen activator inhibitor (PAI)]; and angiogenesis [vascular endothelial growth factor (VEGF)] markers, while propagating antioxidant [glutathione (GSH)], anti-inflammatory (IL-10), and fibrinolytic [tissue plasminogen activator (tPA)] markers and tPA/PAI ratio. In a cellular model, we revealed that the extract, without any toxicity, regulated the levels of cell proliferation and inflammatory (TNF-α), angiogenesis (VEGF), anti-inflammatory (IL-10), M1 [inducible nitric oxide synthase (iNOS)] and M2 [arginase-1 (Arg 1)] biomarkers, and iNOS/Arg-1 ratio towards antifibrotic M1 phenotype of macrophage, in a concentration-dependent manner. Taken together, the current study indicated that C. sativus reduces peritoneal adhesion formation by modulating the macrophage polarization from M2 towards M1 cells.

Safety and Efficacy of a Novel Barrier Film to Prevent Intrauterine Adhesion Formation after Hysteroscopic Myomectomy: The PREG1 Clinical Trial

STUDY OBJECTIVE

To evaluate the safety and potential efficacy of a novel degradable polymer film (DPF) designed to act as a 7-day barrier to prevent intrauterine adhesions (IUAs) after hysteroscopic myomectomy.

DESIGN

A prospective single-arm, first-in-human clinical study.

SETTING

Multicenter study involving 6 centers in France, Belgium, and the Netherlands.

PATIENTS

Women aged 40 years or older with no plans to conceive who qualified for hysteroscopic myomectomy (at least 1 10-mm type 0, 1, or 2 myoma) and had a sounded length of the uterine cavity (fundus to exocervix) ranging between 6 cm and 9 cm were considered eligible for the study.

INTERVENTIONS

The DPF was inserted after hysteroscopic transcervical myoma resection. The women were followed up by a telephone call at 30 days and second-look hysteroscopy 4 to 8 weeks after the procedure.

MEASUREMENTS AND MAIN RESULTS

The chosen safety outcome measures were uterine perforation or cervical trauma at the time of the DPF insertion and unexpected fever, pain, or bleeding beyond 48 hours and up to 30 days after insertion, whereas the outcome measure for efficacy was the absence of IUAs on second-look hysteroscopy. A total of 23 women participated in the study. There were no incidents of uterine perforation or cervical trauma at the time of the DPF insertion. There were no reported adverse effects attributable to the DPF. On second-look hysteroscopy, 20 (87%) of the 23 women had no IUAs.

CONCLUSION

The DPF is a novel, easy-to-apply, and acceptable device to prevent IUAs, with very promising initial safety and efficacy data.

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.

A review: progress in preventing tissue adhesions from a biomaterial perspective

Postoperative adhesions (POA) are one of the main problems suffered by patients and are a common complaint. It is considered to be closely associated with the healing mechanism of damaged tissues. Tissue adhesions accompany other symptoms such as inflammation, pain, and even dyskinesia under certain conditions, compromising the patients' quality of life. On the other hand, common treatments involve high costs, re-surgery or long-term hospital stays. Therefore, alternative approaches need to be formulated so that aforementioned problems can be resolved. To this end, a review of recent advances in this context is imperative. In this review, we have highlighted the mechanism of adhesion formation, advances in common therapeutic approaches, and prospective treatments in preventing tissue adhesions. Based on the literature, it can be determined that the disadvantages of available commercial products in the treatment of tissue adhesion have led researchers to utilize alternative methods for designing anti-adhesive products with different structures such as electrospun fibrous mats, hydrogels, and nanospheres. These studies are on the fast track in producing optimal anti-adhesion materials. We hope that this article can attract attention by showing various mechanisms and solutions involved in adhesion problems and inspire the further development of anti-adhesion biomaterials.

In Vivo Evaluation of the Efficacy and Safety of a Novel Degradable Polymeric Film for the Prevention of Intrauterine Adhesions

STUDY OBJECTIVE

To study the safety of a degradable polymeric film (DPF) and its efficacy on reducing the risk of intrauterine-adhesion (IUA) formation in a rat model.

DESIGN

A series of case-control studies relying on random allocation, where feasible.

SETTING

University and good practice animal laboratories.

ANIMALS

The animal models comprised female and male Oncins France Strain A and female Wistar rats.

INTERVENTION(S) AND MEASUREMENTS

The Oncins France Strain A rats were used for in vivo evaluation of the impact of the DPF on endometrial thickness and its effect on fertility. For in vivo evaluation of the biologic response, 40 Wistar rats were randomly allocated to intervention and control groups, with matched sampling time after surgery. Finally, for the in vivo evaluation of the DPF's efficacy on IUA prevention, a total of 24 Wistar rats were divided into 3 groups: 1 treated with the DPF, 1 treated with hyaluronic acid gel, and a sham group.

MAIN RESULTS

The DPF did not have a significant impact on endometrial thickness, and there were no significant differences in the number of conceived or prematurely terminated pregnancies, confirming its noninferiority to no treatment. The DPF did not induce irritation at 5 days and 28 days. Finally, the DPF significantly reduced the likelihood of complete IUA formation compared with hyaluronic acid gel- and sham-implanted animals, where only 27% of the animals had their uterine cavity obliterated compared with 80% and 100%, respectively.

CONCLUSION

The DPF is a safe film that is effective in preventing IUA formation after intrauterine curettage in rats.

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.

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.

Polysaccharide-based films for the prevention of unwanted postoperative adhesions at biological interfaces

Postoperative adhesions protect, repair, and supply nutrients to injured tissues; however, such adhesions often remain permanent and complicate otherwise successful surgeries by tethering tissues together that are normally separated. An ideal adhesion barrier should not only effectively prevent unwanted adhesions but should be easy to use, however, those that are currently available have inconsistent efficacy and are difficult to handle or to apply. A robust hydrogel film composed of alginate and a photo-crosslinkable hyaluronic acid (HA) derivative (glycidyl methacrylate functionalized hyaluronic acid (GMHA)) represents a solution to this problem. A sacrificial porogen (urea) was used in the film manufacture process to impart macropores that yield films that are more malleable and tougher than equivalent films produced without the sacrificial porogen. The robust mechanical behavior of these templated alginate/GMHA films directly facilitated handling characteristics of the barrier film. In a rat peritoneal abrasion model for adhesion formation, the polysaccharide films successfully prevented adhesions with statistical equivalence to the leading anti-adhesion technology on the market, Seprafilm®. STATEMENT OF SIGNIFICANCE: Postoperative adhesions often remain permanent and complicate otherwise successful surgeries by tethering tissues together that are normally separated and pose potentially significant challenges to patients. Therefore, the generation of adhesion barriers that are easy to deploy during surgery and effectively prevent unwanted adhesions is a big challenge. In this study robust hydrogel films composed of alginate and a photo-crosslinkable hyaluronic acid (HA) derivative (glycidyl methacrylate functionalized HA, GMHA) were fabricated and investigated for their potential to act as a solution to this problem using a rat peritoneal abrasion model for adhesion formation. We observed the polysaccharide films successfully prevented adhesions with statistical equivalence to the leading anti-adhesion technology on the market, Seprafilm®, suggesting that such films represent a promising strategy for the prevention of postoperative adhesions.