Novel superhydrophilic poly(l-lactic acid-co-ε-caprolactone)/fibrinogen electrospun patch for rat abdominal wall reconstruction

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.

Transversalis fascia suture reinforcement may facilitate the performance of electrospun P(LLA-CL) nanoscale fibrinogen mesh in inguinal hernia repair: a prospective single-center cohort study

The aim of this study was to evaluate a new electrospun P(LLA-CL) nanoscale fibrinogen mesh performance in real-world clinical practice. A prospective, single-center evaluation of Lichtenstein inguinal hernia repair using electrospun P(LLA-CL) nanoscale fibrinogen mesh in elderly patients with comorbid diseases was conducted between 2020 and 2022. A suture reinforcement of transversalis fascia was applied before mesh implantation. Hernia recurrence, pain score and overall complication rate were measured. A total of 52 inguinal hernias in 48 patients were included. The age of patients ranged from 33 to 95 years, with a median of 78 years. Comorbid conditions included cardiopulmonary disease, organ dysfunction, anticoagulant use, diabetes and smoking. By optimizing the physical condition perioperatively, all patients finished treatment successfully. Four cases recurred secondary to direct hernias or combined hernias and were diagnosed in the first 24 case cohort during follow-up. With surgical procedural modification involving strengthening the posterior inguinal floor by reef-up suturing of the transversalis fascia and the inferior edge of mesh slit to accommodate the spermatic cord, no further recurrence was diagnosed. Postoperative pain was mild and the pain score decreased three months after surgery compared to 1 week after surgery (p = 0.0099). No severe complications occurred, while seroma occurred in six cases. Electrospun P(LLA-CL) nanoscale fibrinogen mesh is safe and effective in repairing inguinal hernias in elderly patients with comorbid disease. A strengthening of the transversalis fascia by suturing may enhance the performance of this mesh.

Preclinical animal study of electrospun poly (l-lactide-co-caprolactone) and formulated porcine fibrinogen for full-thickness diabetic wound regeneration

Diabetic foot ulcer is one of the most serious chronic complications of diabetes mellitus. It may lead to amputation of the lower extremities for diabetics. Our study was to evaluate the effect of electrospun poly (L-lactide-co-caprolactone) and formulated porcine fibrinogen (PLCL/Fg) wound dressing on animal wound model. A blend ratio of PLCL/Fg scaffold was 4 (PLCL):1 (Fg). The scanning electron microscopy findings showed that the fibers' diameter was 122.5 ± 80.3 nm, and the tensile strength was 9.2 ± 0.2 MPa. In-vivo study of the hog normal model demonstrated that PLCL/Fg dressing had better biocompatibility, degradability, and ability to restore the skin's normal structure. We evaluated the wound healing processes in the rat diabetic model by macroscopic observation and histological observation at 1, 2, and 3 post-operation weeks. In our study, the PLCL/Fg group performed better 3 weeks after surgery, in terms of macroscopic healing and scarring. After surgery, the PLCL/Fg group showed better fibroblast accumulation, tissue granulation, and collagen expression than the control group. Topical treatment with PLCL/Fg dressing effectively enhanced wound healing in both normal and hyperglycemic conditions, suggesting that it may possess wound-healing potential.

Six-year follow-up outcomes of the P(LLA-CL)/Fg bio-patch for anterior vaginal wall prolapse treatment

INTRODUCTION AND HYPOTHESIS

There were few data about the long-term outcomes of bio-compatible patches for pelvic organ prolapse (POP). The efficacy of poly (L-lactide-co-caprolactone) blended with fibrinogen [P(LLA-CL)/Fg] bio-patches were investigated for anterior vaginal wall prolapse treatment in a 6-year follow-up.

METHODS

The P(LLA-CL)/Fg bio-patch was fabricated through electrospinning. Nineteen patients with symptomatic anterior prolapse (Pelvic Organ Prolapse Quantification [POP-Q] stage ≥ 2) were treated with anterior pelvic reconstruction surgery using a P(LLA-CL)/Fg bio-patch and were followed up at 1, 2, 3, 6 months, and 6 years. The primary outcome was objective anatomical cure (anterior POP-Q stage ≤ 1). Secondary outcomes included complications, MRI evaluation, and scores of the Pelvic Floor Impact Questionnaire-7 (PFIQ-7) and the Pelvic Floor Distress Inventory-20 (PFDI-20).

RESULTS

The micro-morphology of the bio-patch resembled the extracellular matrix, which was suitable for the growth of fibroblasts. Sixteen (84.2%) patients were finally assessed, with a mean follow-up of 6.08 ± 0.18 years. The cure rate without anterior prolapse recurrence was 93.8% at 6 years. Compared with baseline, the POP-Q measurements of Aa, Ba, and C points and scores of PFIQ-7 and PFDI-20 manifested significant differences at all times (all p < 0.05). One (5.26%) case of bio-patch-related infection, 1 (5.26%) case of urinary retention, and no exposures and erosion occurred. MRI evaluation showed that the bio-patch gradually degraded to fragments at 1 month and was completely absorbed at 3 months.

CONCLUSIONS

Among long-term follow-ups, anterior pelvic reconstruction surgery with a P(LLA-CL)/Fg bio-patch demonstrated significant improvements in anatomical correction of anterior pelvic prolapse and pelvic function without severe morbidity.

Inflammation Self-Limiting Electrospun Fibrous Tape via Regional Immunity for Deep Soft Tissue Repair

Overexpression of inflammatory cytokines and chemokines occurs at deep soft tissue injury sites impeding the inflammation self-limiting and impairing the tissue remodeling process. Inspired by the electrostatically extracellular matrix (ECM) binding property of the inflammatory signals, an inflammation self-limiting fibrous tape is designed by covalently modifying the thermosensitive methacrylated gelatin (GelMA) and negatively charged methacrylated heparin (HepMA) hydrogel mixture with proper ratio onto the electrospun fibrous membrane by mild alkali hydrolysis and carboxyl-amino condensation reaction to restore inflammation self-limiting and promote tissue repair via regional immunity regulation. While the GelMA guarantees cell compatibility, the negatively charged HepMA successfully adsorbs the inflammatory cytokines and chemokines by electrostatic interactions and inhibits immune cell migration in vitro. Furthermore, in vivo inflammation self-limiting and regional immunity regulation efficacy is evaluated in a rat abdominal hernia model. Reduced local inflammatory cytokines and chemokines in the early stage and increased angiogenesis and ECM remodeling in the later phase confirm that the tape is an approach to maintain an optimal regional immune activation level after soft tissue injury. Overall, the reported electrospun fibrous tape will find its way into clinical transformation and solve the challenges of deep soft tissue injury.

Adipose-Derived Stem Cells Based on Electrospun Biomimetic Scaffold Mediated Endothelial Differentiation Facilitating Regeneration and Repair of Abdominal Wall Defects via HIF-1α/VEGF Pathway

Application of synthetic or biological meshes is the main therapy for the repair and reconstruction of abdominal wall defects, a common disease in surgery. Currently, no ideal materials are available, and there is an urgent need to find appropriate ones to satisfy clinical needs. Electrospun scaffolds have drawn attention in soft tissue reconstruction. In this study, we developed a novel method to fabricate a composite electrospun scaffold using a thermoresponsive hydrogel, poly (N-isopropylacrylamide)-block-poly (ethylene glycol), and a biodegradable polymer, polylactic acid (PLA). This scaffold provided not only a high surface area/volume ratio and a three-dimensional fibrous matrix but also high biocompatibility and sufficient mechanical strength, and could simulate the native extracellular matrix and accelerate cell adhesion and proliferation. Furthermore, rat adipose-derived stem cells (ADSCs) were seeded in the composite electrospun scaffold to enhance the defect repair and regeneration by directionally inducing ADSCs into endothelial cells. In addition, we found early vascularization in the process was regulated by the hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathway. In our study, overexpression of HIF-1α/VEGF in ADSCs using a lentivirus system promoted early vascularization in the electrospun scaffolds. Overall, we expect our composite biomimetic scaffold method will be applicable and useful in abdominal wall defect regeneration and repair in the future.

Regenerated silk fibroin (RSF) electrostatic spun fibre composite with polypropylene mesh for reconstruction of abdominal wall defects in a rat model

Abdominal wall defects are associated with abdominal wall surgery, infection and tumour resection. Polypropylene (PP) mesh, which has excellent mechanical strength, is currently the primary clinical repair material. In repairing the abdominal wall, the mesh can erode the bowel and cause other problems. Constructing a barrier that induces a weak inflammatory response and promotes rapid recovery of the peritoneum is important. We used electrospinning technology to construct a silk fibroin coating on the abdominal surface of a PP patch. A rat model was used to compare the inflammatory responses, regeneration of peritoneal tissue, and antiadhesion effects of electrospun regenerated silk fibroin (RSF) coatings, polycaprolactone (PCL) coatings, and noncoated PP meshes. The inflammatory responses, antiadhesion fractions, and areas of RSF and PCL were better than those of PP at 6 weeks. RSF was associated with complete peritoneal regeneration, in contrast to PCL. At 12 weeks, the structure of the PCL peritoneum was unstable, and the adhesion fraction and area were significantly higher than those of RSF. The intact peritoneum could not be effectively regenerated. The RSF group exhibited lower IL-6 levels than the PCL and PP groups but higher VEGF, IL-10 and TGF-β levels, making RSF more conducive to the regeneration of peritoneal and abdominal wall tissues.

Peptide-protein based nanofibers in pharmaceutical and biomedical applications

In recent years, electrospun fibers have found wide use, especially in pharmaceutical area and biomedical applications, related to the various advantages such as high surface-volume ratio, high solubility and having wide usage areas they have provided. Biocompatible and biodegradable fibers can be obtained by using peptide-protein structures of plant and animal derived along with synthetic polymers. Plant-derived proteins used in nanofiber production can be listed as, zein, soy protein, and gluten and animal derived proteins can be listed as casein, silk fibroin, hemoglobine, bovine serum albumin, elastin, collagen, gelatin, and keratin. Plant and animal proteins and synthetic peptides used in electrospun fiber production were reviewed in detail. In addition, the important physical properties of these materials for the electrospinning process and their use in pharmaceutical and biomedical areas were discussed.

The effects of cross-linked/uncross-linked electrospun fibrinogen/polycaprolactone nanofibers on the proliferation of normal human epidermal keratinocytes

The aim of this study was an investigation on the proliferation rate of normal human epidermal keratinocytes (NHEK) on the cross-linked and uncross-linked fibrinogen/polycaprolactone (Fbg/PCL) nanofibers to determine a suitable scaffold for skin tissue engineering. Nanofibrous scaffolds were prepared by electrospinning of different weight ratios of Fbg to PCL and were analyzed as morphology, surface chemical properties and cytocompatibility by scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, respectively. The diameters of the blended uncross-linked scaffolds were in the range of 124±43 nm–209±155 nm. Cross-linking of scaffolds with glutaraldehyde did not make a significant change in the diameter of blended scaffolds in 16 h. Cross-linking also improved the tensile strength and weight loss rate of scaffolds. However, cross-linking demonstrated an unfavorable effect on the attachment and proliferation of NHEK cells. The proliferation study revealed that uncross-linked scaffolds containing 50% and 70% Fbg provide a better environment for the growth of NHEK cells, and can be considered promising scaffolds in tissue engineering applications.