Functionalized Strategies and Mechanisms of the Emerging Mesh for Abdominal Wall Repair and Regeneration

Ibuprofen-loaded bilayer electrospun mesh modulates host response toward promoting full-thickness abdominal wall defect repair

Pro-inflammatory response impairs the constructive repair of abdominal wall defects after mesh implantation. Electrospinning-aid functionalization has the potential to improve the highly orchestrated response by attenuating the over-activation of foreign body reactions. Herein, we combined poly(L-lactic acid-co-caprolactone) (PLLA-CL) with gelatin proportionally via electrospinning, with Ibuprofen (IBU) incorporation to fabricate a bilayer mesh for the repair improvement. The PLLA-CL/gelatin/IBU (PGI) mesh was characterized in vitro and implanted into the rat model with a full-thickness defect for a comprehensive evaluation in comparison to the PLLA-CL/gelatin (PG) and off-the-shelf small intestinal submucosa (SIS) meshes. The bilayer PGI mesh presented a sustained release of IBU over 21 days with degradation in vitro and developed less-intensive intraperitoneal adhesion along with a histologically weaker inflammatory response than the PG mesh after 28 days. It elicited an M2 macrophage-dominant foreign body reaction within the process, leading to a pro-remodeling response similar to the biological SIS mesh, which was superior to the PG mesh. The PGI mesh provided preponderant mechanical supports over the SIS mesh and the native abdominal wall with similar compliance. Collectively, the newly developed mesh advances the intraperitoneal applicability of electrospun meshes by guiding a pro-remodeling response and offers a feasible functionalization approach upon immunomodulation.

Design and development of pH-responsive levofloxacin-loaded metal-organic framework for the promising treatment of pediatric abdominal wound repair

With over 9 million fatalities per year expected by 2030, infectious diseases will remain a significant burden on the world economy and cause high mortality rates. An excellent method to increase the bioactivity of levofloxacin (LEV) in pediatric abdominal wound repair is the finding of a stimuli-based drug delivery system (DDS). We designed and developed an LEV incorporated with zeolite imidazole framework-8 (ZIF-8) as a promising nanocarrier for wound healing applications. The spectral analysis and morphological analysis confirm the formation of our newly fabricated composites. Mouse embryonic fibroblast NIH3T3 cells, the cytotoxicity, cytocompatibility, and cell proliferation characteristics of LEV@ZIF-8 were evaluated in vitro. LEV@ZIF-8 composite considerably improved the biocompatibility against NIH3T3 cells after 72-h of exposure, according to in vitro experiments. Under acidic circumstances, the pH-responsive drug release studies exhibit superior LEV release, and in physiological circumstances, there is no unintended drug release. The LEV@ZIF-8 composite-treated cells demonstrate the most remarkable cell growth and migration method in a very short time, according to the results of the wound scratch experiment. The composite exposure concentration depended on inhibition against various microorganisms in the antibacterial activity testing. According to the study, LEV@ZIF-8 are appropriate and effective DDS for stimuli-based pediatric abdominal wound repair.

The utilization of chitosan/Bletilla striata hydrogels to elevate anti-adhesion, anti-inflammatory and pro-angiogenesis properties of polypropylene mesh in abdominal wall repair

Polypropylene (PP) mesh is commonly used in abdominal wall repair due to its ability to reduce the risk of organ damage, infections and other complications. However, the PP mesh often leads to adhesion formation and does not promote functional tissue repair. In this study, we synthesized one kind of aldehyde Bletilla striata polysaccharide (BSPA) modified chitosan (CS) hydrogel based on Schiff base reaction. The hydrogel exhibited a porous network structure, a highly hydrophilic surface and good biocompatibility. We wrapped the PP mesh inside the hydrogel and evaluated the performance of the resulting composites in a bilateral 1 × 1.5 cm abdominal wall defect model in rats. The results of gross observation, histological staining and immunohistochemical staining demonstrated the positive impact of the CS hydrogel on anti-adhesion and wound healing effects. Notably, the addition of BSPA to the CS hydrogel further improved the performance of the composites in vivo, promoting wound healing by enhancing collagen deposition and capillary rearrangement. This study suggested that the BSPA-modified CS hydrogel significantly promoted the anti-adhesion, anti-inflammatory and pro-angiogenesis properties of PP meshes during the healing process. Overall, this work offers a novel approach to the design of abdominal wall repair patches.

A Review of Advanced Abdominal Wall Hernia Patch Materials

Tension-free abdominal wall hernia patch materials (AWHPMs) play an important role in the repair of abdominal wall defects (AWDs), which have a recurrence rate of <1%. Nevertheless, there are still significant challenges in the development of tailored, biomimetic, and extracellular matrix (ECM)-like AWHPMs that satisfy the clinical demands of abdominal wall repair (AWR) while effectively handling post-operative complications associated with abdominal hernias, such as intra-abdominal visceral adhesion and abnormal healing. This extensive review presents a comprehensive guide to the high-end fabrication and the precise selection of these advanced AWHPMs. The review begins by briefly introducing the structures, sources, and properties of AWHPMs, and critically evaluates the advantages and disadvantages of different types of AWHPMs for AWR applications. The review subsequently summarizes and elaborates upon state-of-the-art AWHPM fabrication methods and their key characteristics (e.g., mechanical, physicochemical, and biological properties in vitro/vivo). This review uses compelling examples to demonstrate that advanced AWHPMs with multiple functionalities (e.g., anti-deformation, anti-inflammation, anti-adhesion, pro-healing properties, etc.) can meet the fundamental clinical demands required to successfully repair AWDs. In particular, there have been several developments in the enhancement of biomimetic AWHPMs with multiple properties, and additional breakthroughs are expected in the near future.

Shape-Configurable Mesh for Hernia Repair by Synchronizing Anisotropic Body Motion

Continuous progress has been made in elucidating the relationship between material property, device design, and body function to develop surgical meshes. However, an unmet need still exists wherein the surgical mesh can handle the body motion and thereby promote the repair process. Here, the hernia mesh design and the advanced polymer properties are tailored to synchronize with the anisotropic abdominal motion through shape configuration. The thermomechanical property of shape configurable polymer enables molding of mesh shape to fit onto the abdominal structure upon temperature shift, followed by shape fixing with the release of the heat energy. The microstructural design of mesh is produced through finite element modeling to handle the abdominal motion efficiently through the anisotropic longitudinal and transverse directions. The design effects are validated through in vitro, ex vivo, and in vivo mechanical analyses using a self-configurable, body motion responsive (BMR) mesh. The regenerative function of BMR mesh leads to effective repair in a rat hernioplasty model by effectively handling the anisotropic abdomen motion. Subsequently, the device-tissue integration is promoted by promoting healthy collagen synthesis with fibroblast-to-myofibroblast differentiation. This study suggests a potential solution to promote hernia repair by fine-tuning the relationship between material property and mesh design.

Novel Material Optimization Strategies for Developing Upgraded Abdominal Meshes

Over 20 million hernias are operated on globally per year, with most interventions requiring mesh reinforcement. A wide range of such medical devices are currently available on the market, most fabricated from synthetic polymers. Yet, searching for an ideal mesh is an ongoing process, with continuous efforts directed toward developing upgraded implants by modifying existing products or creating innovative systems from scratch. In this regard, this review presents the most frequently employed polymers for mesh fabrication, outlining the market available products and their relevant characteristics, further focusing on the state-of-the-art mesh approaches. Specifically, we mainly discuss recent studies concerning coating application, nanomaterials addition, stem cell seeding, and 3D printing of custom mesh designs.

Abdominal wall hernia repair: from prosthetic meshes to smart materials

Hernia reconstruction is one of the most frequently practiced surgical procedures worldwide. Plastic surgery plays a pivotal role in reestablishing desired abdominal wall structure and function without the drawbacks traditionally associated with general surgery as excessive tension, postoperative pain, poor repair outcomes, and frequent recurrence. Surgical meshes have been the preferential choice for abdominal wall hernia repair to achieve the physical integrity and equivalent components of musculofascial layers. Despite the relevant progress in recent years, there are still unsolved challenges in surgical mesh design and complication settlement. This review provides a systemic summary of the hernia surgical mesh development deeply related to abdominal wall hernia pathology and classification. Commercial meshes, the first-generation prosthetic materials, and the most commonly used repair materials in the clinic are described in detail, addressing constrain side effects and rational strategies to establish characteristics of ideal hernia repair meshes. The engineered prosthetics are defined as a transit to the biomimetic smart hernia repair scaffolds with specific advantages and disadvantages, including hydrogel scaffolds, electrospinning membranes, and three-dimensional patches. Lastly, this review critically outlines the future research direction for successful hernia repair solutions by combing state-of-the-art techniques and materials.

Physiologic Cyclical Load on Inguinal Hernia Scaffold ProFlor Turns Biological Response into Tissue Regeneration

Surgical repair of groin protrusions is one of the most frequently performed procedures. Currently, open or laparoscopic repair of inguinal hernias with flat meshes deployed over the hernial defect is considered the gold standard. However, fixation of the implant, poor quality biologic response to meshes and defective management of the defect represent sources of continuous debates. To overcome these issues, a different treatment concept has recently been proposed. It is based on a 3D scaffold named ProFlor, a flower shaped multilamellar device compressible on all planes. This 3D device is introduced into the hernial opening and, thanks to its inherent centrifugal expansion, permanently obliterates the defect in fixation-free fashion. While being made of the same polypropylene material as conventional hernia implants, the 3D design of ProFlor confers a proprietary dynamic responsivity, which unlike the foreign body reaction of flat/static meshes, promotes a true regenerative response. A long series of scientific evidence confirms that, moving in compliance with the physiologic cyclical load of the groin, ProFlor attracts tissue growth factors inducing the development of newly formed muscular, vascular and nervous structures, thus re-establishing the inguinal barrier formerly wasted by hernia disease. The development up to complete maturation of these highly specialized tissue elements was followed thanks to biopsies excised from ProFlor from the short-term up to years post implantation. Immunohistochemistry made it possible to document the concurrence of specific growth factors in the regenerative phenomena. The results achieved with ProFlor likely demonstrate that modifying the two-dimensional design of hernia meshes into a 3D outline and arranging the device to respond to kinetic stresses turns a conventional regressive foreign body response into advanced probiotic tissue regeneration.

Polypropylene mesh combined with electrospun poly (L-lactic acid) membrane in situ releasing sirolimus and its anti-adhesion efficiency in rat hernia repair

This study developed, a novel polypropylene (PP) mesh combined with poly (L-lactic acid) (PLA) electrospun nanofibers loaded sirolimus (SRL). The PP mesh was combined with PLA/SRL (1/0, 1/0.01, 1/0.02; mass ratios) composed electrospun membrane characterized by FTIR spectroscopy, XPS and SEM, and evaluated for cytocompatibility in vitro. In an in vivo study, a total of 84 Sprague-Dawley rats were employed to evaluate the efficacy of the novel composite PP mesh anti-adhesion, mechanical properties and inflammation. As a results, the PLA/SRL membrane could compound with PP mesh stably and load SRL. Although tensile testing showed that the mechanical properties of composite mesh decreased in vivo, the integration strength between the tissue and mesh was still able to counteract intra-abdominal pressure. Compared with the native PP mesh group, the novel PP mesh group showed a lower score for abdominal adhesion and inflammation. More importantly, the novel PP mesh completely integrated with the abdominal wall and had sufficient mechanical strength to repair abdominal wall defects.

Biodegradable polyurethane scaffolds in regenerative medicine: Clinical translation review

Early explorations of tissue engineering and regenerative medicine concepts commonly utilized simple polyesters such as polyglycolide, polylactide, and their copolymers as scaffolds. These biomaterials were deemed clinically acceptable, readily accessible, and provided processability and a generally known biological response. With experience and refinement of approaches, greater control of material properties and integrated bioactivity has received emphasis and a broadened palette of synthetic biomaterials has been employed. Biodegradable polyurethanes (PUs) have emerged as an attractive option for synthetic scaffolds in a variety of tissue applications because of their flexibility in molecular design and ability to fulfill mechanical property objectives, particularly in soft tissue applications. Biodegradable PUs are highly customizable based on their composition and processability to impart tailored mechanical and degradation behavior. Additionally, bioactive agents can be readily incorporated into these scaffolds to drive a desired biological response. Enthusiasm for biodegradable PU scaffolds has soared in recent years, leading to rapid growth in the literature documenting novel PU chemistries, scaffold designs, mechanical properties, and aspects of biocompatibility. Despite the enthusiasm in the field, there are still few examples of biodegradable PU scaffolds that have achieved regulatory approval and routine clinical use. However, there is a growing literature where biodegradable PU scaffolds are being specifically developed for a wide range of pathologies and where relevant pre-clinical models are being employed. The purpose of this review is first to highlight examples of clinically used biodegradable PU scaffolds, and then to summarize the growing body of reports on pre-clinical applications of biodegradable PU scaffolds.

Antimicrobial Meshes for Hernia Repair: Current Progress and Perspectives

Recent advances in the development of biomaterials have given rise to new options for surgery. New-generation medical devices can control chemical breakdown and resorption, prevent post-operative adhesion, and stimulate tissue regeneration. For the fabrication of medical devices, numerous biomaterials can be employed, including non-degradable biomaterials (silicone, polypropylene, expanded polytetrafluoroethylene) or biodegradable polymers, including implants and three-dimensional scaffolds for tissue engineering, which require particular physicochemical and biological properties. Based on the combination of new generation technologies and cell-based therapies, the biocompatible and bioactive properties of some of these medical products can lead to progress in the repair of injured or harmed tissue and in tissue regeneration. An important aspect in the use of these prosthetic devices is the associated infection risk, due to the medical complications and socio-economic impact. This paper provides the latest achievements in the field of antimicrobial surgical meshes for hernia repair and discusses the perspectives in the development of these innovative biomaterials.