Histologic Inflammatory Response to Transvaginal Polypropylene Mesh: A Systematic Review

Self-gripping versus polypropylene mesh for incisional hernia repair in a rat model

BACKGROUND

Self-gripping mesh, made of monofilament polypropylene and covered by a layer of polylactic acid micro-hooks, is applied in ventral hernia repair, whereas cytological change and collagen expression around the mesh are rarely reported. The objective of this research was to compare inflammatory response and collagen proliferation between self-gripping and polypropylene mesh in rat model of incisional hernia.

METHODS

Forty-five rats were randomly divided into unrepaired (UR) group, polypropylene (PP) mesh group, and self-gripping (SG) mesh group and euthanized at 1, 2 and 4 weeks postoperatively. The levels of inflammation, neovascularization, and collagen expression were measured by immunohistochemistry, quantitative real-time polymerase chain reaction, and Western blot.

RESULTS

One rat died and others developed typical incisional hernia in UR group, and hematoma, seroma, or wound infection were not observed in PP and SG groups. There was no significant difference in mesh shrinkage and inflammatory infiltration between PP and SG groups. With regard to neovascularization, 2 groups were comparable at 1 and 2 weeks, while the neovascularization score of PP group was statistically higher than that of SG group at 4 weeks. One week after surgery, the amounts of Collagen I (Col I) mRNA in PP group were significantly higher than SG group, while the amounts of Collagen III (Col III) mRNA were comparable between 2 groups. Two weeks following operation, the expressions of Col I mRNA and Col III mRNA in PP group were statistically lower than those in SG group. Four weeks postoperatively, the levels of Col I mRNA and Col III mRNA in PP group were significantly higher than those in SG group.

CONCLUSION

Self-gripping mesh induced comparable inflammatory response and collagen proliferation compared with polypropylene mesh in a rat model.

REGISTRATION NUMBER

ZZU-LAC2023080121.

Properties of Electrospun Fibers That Influence Foreign Body Response Modulation

Improving the utility of biomedical devices implanted in subcutaneous tissue by modulating the innate immune response common to these implants is of great interest to improve their utility. Uncontrolled, most biomedical devices produce an immune reaction known broadly as the foreign body response (FBR), which ultimately isolates the device from the native tissue. The use of electrospun fibers to create a porous surface that promotes tissue in-growth and regeneration represents a new paradigm in FBR modulation. A vast number of parameters can be adjusted in the electrospinning process to tune the type and quality of the resulting electrospun matrix, which in turn has varying outcomes with respect to the FBR. In this review, the fabrication and utility of electrospun fiber scaffolds for mitigating the FBR are described, with details of how fiber properties and surface modifications alter immune response for specific biomedical applications.

Prediction of successful revision surgery for mesh-related complaints after inguinal hernia and pelvic organ prolapse repair

PURPOSE

With this retrospective case series, we aim to identify predictors for reduction of pain after mesh revision surgery in patients operated for inguinal hernia or pelvic organ prolapse with a polypropylene implant. Identifying these predictors may aid surgeons to counsel patients and select appropriate candidates for mesh revision surgery.

METHODS

Clinical records before and after mesh revision surgery from 221 patients with chronic postoperative inguinal pain (CPIP) and 59 patients with pain after pelvic organ prolapse (POP) surgery were collected at two experienced tertiary referral centers. Primary outcome was patient reported improvement of pain after revision surgery. A multivariable logistic regression model was used to specify predictors for pain reduction.

RESULTS

The multivariable logistic regression was performed for each patient group separately. Patients with CPIP had higher chances of improvement of pain when time between mesh placement and mesh revision surgery was longer, with an OR of 1.19 per year. A turning point in chances of risks and benefits was demonstrated at 70 months, with improved outcomes for patients with revision surgery ≥ 70 months (OR 2.86). For POP patients, no statistically significant predictors for reduction of pain after (partial) removal surgery could be identified.

CONCLUSION

A longer duration of at least 70 months between implantation of inguinal mesh and revision surgery seems to give a higher chance on improvement of pain. Caregivers should not avoid surgery based on a longer duration of symptoms when an association between symptoms and the location of the mesh is found.

The Use of Platelet-Rich Fibrin and Polypropylene Mesh in Repair of Nasal Septal Perforation

OBJECTIVE

In this study, we aimed to investigate the effectiveness of the use of polypropylene mesh and platelet-rich fibrin (PRF) in nasal septal perforation (NSP) repair.

STUDY DESIGN

Prospective experimental study.

SETTING

Laboratory.

METHODS

Twenty-four adult male New Zealand rabbits were used in our study. In all subjects, a 10 × 10 mm perforation was created in the septum. The subjects were divided into 3 equal groups according to the different methods used in perforation closure. The bilateral mucosal flap was used in the control group, polypropylene mesh + bilateral mucosal flap in the mesh group, and polypropylene mesh + bilateral mucosal flap + PRF in the mesh + PRF group.

RESULTS

NSP treatment success rate was found to be significantly higher in the mesh (4/6, 66.7%) and mesh + PRF (6/6, 100%) groups compared to the control group (0/6, 0%). Re-epithelialization score was higher in the mesh + PRF group and the control group compared to the mesh group. While the necrosis, neutrophil, and abscess scores were highest in the mesh group, they were similar to the control group in the mesh + PRF group.

CONCLUSIONS

While polypropylene mesh significantly increases the success rate in NSP repair, it causes severe inflammatory responses. However, when polypropylene mesh is combined with PRF, it both increases the rate of perforation closure and significantly reduces the complications associated with the use of mesh.

Features of Cell Reactions during Implantation of Biodegradable Polymer and Polypropylene in the Experiment

Quantitative and qualitative characteristics of cell infiltrates in male Wistar rats were studied from 14 days to 12 months after implantation of polypropylene and a biodegradable polymer obtained by electrospinning and consisting of 65% polycaprolactone and 35% polytrimethylene carbonate. It was found that a predominantly macrophage-giant cell reaction developed around the biodegradable polymer; it spread into the matrix and the number of cells in the infiltrate decreased, as the degradation progressed. Around polypropylene, mainly lymphocytic and leukocytic reaction was seen; it also decreased with time, but was characterized by a reverse increase in the number of lymphocytes. Immunohistochemical analysis showed that the proportion of CD38⁺ cells 12 months after implantation increased around polypropylene to a greater extent than around the biodegradable polymer, while the proportion of CD68⁺ cells decreased. These findings suggest that implantation of a biodegradable polymer caused no prolonged lymphocytic and plasma cell reaction in animals as in the case of polypropylene, which indicates that biodegradable polymer is a promising material for tissue engineering.

Collagen Deposition and Inflammatory Response Associated with Macroporous Mesh Shrinkage in Incisional Hernia Repair: A Rat Model

Background: Mesh repair is the current recommendation for the treatment of incisional hernia; however, the best mesh has yet to be determined. The objective of this study was to compare the inflammatory response and collagen deposition in primary incisional hernia repair (P) and different macroporous mesh materials, including polypropylene with poliglecaprone (PP-PG), polyvinylidene fluoride (PVDF), and polyester (PE), using quantitative methods. Methods: Sixty male rats were divided into four groups. Anterior abdominal wall defects were created and either suture or mesh repair was done. Rats were euthanized on days 14, 90, and 180, and the gross findings were recorded. The inflammatory and collagen levels in the abdominal wall tissues were measured using enzyme-linked immunosorbent assay (ELISA). Results: The PE group demonstrated significant mesh shrinkage at 180 days. The extent of PE mesh shrinkage ranged from 22-42% (mean = 30.49%). At 14 days, the PVDF group had higher interleukin-6 (IL-6) levels than the PP-PG (P = .004) and PE groups (P = .019). At 90 days, the collagen type I (Col I) levels in the PE group were significantly lower than those in the others, and the collagen type I/III (Col I/III) ratios in the PE group were lower than those in the P group (P = .006). Conclusions: The persistently high IL-6 levels until 180 days and the decrease in Col I levels and Col I/III ratio at 90 days seem to predict mesh shrinkage at 180 days. The mesh induces high Col I levels, but those associated with low Col III levels should be preferred.

Tissue response, macrophage phenotype, and intrinsic calcification induced by cardiovascular biomaterials: Can clinical regenerative potential be predicted in a rat subcutaneous implant model?

The host immune response to an implanted biomaterial, particularly the phenotype of infiltrating macrophages, is a key determinant of biocompatibility and downstream remodeling outcome. The present study used a subcutaneous rat model to compare the tissue response, including macrophage phenotype, remodeling potential, and calcification propensity of a biologic scaffold composed of glutaraldehyde-fixed bovine pericardium (GF-BP), the standard of care for heart valve replacement, with those of an electrospun polycarbonate-based supramolecular polymer scaffold (ePC-UPy), urinary bladder extracellular matrix (UBM-ECM), and a polypropylene mesh (PP). The ePC-UPy and UBM-ECM materials induced infiltration of mononuclear cells throughout the thickness of the scaffold within 2 days and neovascularization at 14 days. GF-BP and PP elicited a balance of pro-inflammatory (M1-like) and anti-inflammatory (M2-like) macrophages, while UBM-ECM and ePC-UPy supported a dominant M2-like macrophage phenotype at all timepoints. Relative to GF-BP, ePC-UPy was markedly less susceptible to calcification for the 180 day duration of the study. UBM-ECM induced an archetypical constructive remodeling response dominated by M2-like macrophages and the PP caused a typical foreign body reaction dominated by M1-like macrophages. The results of this study highlight the divergent macrophage and host remodeling response to biomaterials with distinct physical and chemical properties and suggest that the rat subcutaneous implantation model can be used to predict in vivo biocompatibility and regenerative potential for clinical application of cardiovascular biomaterials.

Are polypropylene mesh implants associated with systemic autoimmune inflammatory syndromes? A systematic review

Purpose

The surgical implantation of polypropylene (PP) meshes has been linked to the occurrence of systemic autoimmune disorders. We performed a systematic review to determine whether PP implants for inguinal, ventral hernia or pelvic floor surgery are associated with the development of systemic autoimmune syndromes.

Methods

We searched Embase, Medline, Web of Science, Scopus, Cochrane library, clinicaltrialsregister.eu, clinicaltrails.gov and WHO-ICTR platform. Last search was performed on November 24th 2021. All types of studies reporting systemic inflammatory/autoimmune response in patients having a PP implant for either pelvic floor surgery, ventral or inguinal hernia repair were included. Animal studies, case reports and articles without full text were excluded. We intended to perform a meta-analysis. The quality of evidence was assessed with the Newcastle–Ottawa Scale. This study was registered at Prospero (CRD42020220705).

Results

Of 2137 records identified, 4 were eligible. Two retrospective matched cohort studies focused on mesh surgery for vaginal prolapse or inguinal hernia compared to hysterectomy and colonoscopy, respectively. One cohort study compared the incidence of systemic conditions in women having urinary incontinence surgery with and without mesh. These reports had a low risk of bias. A meta-analysis showed no association when comparing systemic disease between mesh and control groups. Calculated risk ratio was 0.9 (95% CI 0.82–0.98). The fourth study was a case series with a high risk of bias, with a sample of 714 patients with systemic disease, 40 of whom had PP mesh implanted.

Conclusion

There is no evidence to suggest a causal relationship between being implanted with a PP mesh and the occurrence of autoimmune disorders.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10029-021-02553-y.

Morphogenetic Aspects of the Response of Vaginal Tissues to Polypropylene Implants as the Basis of Mesh-Associated Complications

Morphometric and immunohistochemical examination of the vaginal mucosa before and 12 months after installation of polypropylene implants for the correction of stress urinary incontinence was performed in 20 patients with genital prolapse. The research results confirmed good biocompatibility of polypropylene and the formation of full-fledged connective tissue in the vaginal mucosa, but revealed the presence of a weak lymphocytic reaction to polypropylene 12 months after surgery. According to immunohistochemical study, increased contents of B lymphocytes and plasma cells responsible for the inductive and productive stages of the immune response were revealed in the vaginal mucosa around the implants 12 months after surgery. This reaction in the presences of provoking factors can lead to the development of inflammation and erosion, a type of mesh-associated complications.

Autoimmune [auto-inflammatory] syndrome induced by adjuvants (ASIA): Case report after inguinal hernia repair with mesh

INTRODUCTION

There has been a great advance in the treatment of inguinal hernias with a significant reduction in recurrences with the use of polypropylene mesh. Local complications such as infections, rejection, and chronic pain are widely studied and reported in the literature. The Autoimmune [Auto-inflammatory] Syndrome Induced by Adjuvants (ASIA) is little known and can be triggered by using polypropylene mesh.

PRESENTATION OF THE CASE

33-year-old female patient, married, and an administrative manager. History of smoking, previous breast surgery with silicone prosthesis, appendectomy. One year and four months ago, she underwent bilateral inguinal hernioplasty by laparoscopy. Shortly after the inguinal hernia surgery, systemic, urinary symptoms, and chronic local pain appeared. She reported low back pain, fatigue, memory loss, and mood swings associated with limiting pelvic pain, dysuria, and dyspareunia. We performed a robotic surgical procedure to remove the meshes bilaterally. Three days after surgery, the patient was discharged with adequate pain control, without the need for opioids. During outpatient follow-up, there was a significant improvement in symptoms, both local and systemic.

DISCUSSION

Local complications with the use of polypropylene mesh to repair inguinal hernias are well described in the literature, highlighting chronic postoperative pain that can affect 10-20% of patients. Recently, polypropylene prostheses have been found to act as adjuvants and may be the trigger for an exacerbated immune response adaptive to an autoantigen. Thus, being capable of causing an autoimmune disease variant of the Autoimmune [Auto-inflammatory] Syndrome Induced by Adjuvants (ASIA), described by Shoenfeld and Agmon-Levin in 2011.

CONCLUSION

In addition to local complications, systemic symptoms related to the use of polypropylene mesh can also occur. In the Autoimmune [Auto-inflammatory] Syndrome Induced by Adjuvants (ASIA), systemic symptoms, for being nonspecific, make diagnosis difficult and are often not attributed to the use of mesh.

Histamine augments collagen content via H1 receptor stimulation in cultures of myofibroblasts taken from wound granulation tissue

The inflammatory reaction influences the deposition of collagen within wound granulation tissue. The aim of the present study is to determine whether histamine acting directly on myofibroblasts derived from wound granulation tissue may influence collagen deposition. It also identifies the histamine receptor involved in this process. The experiments were carried out on cells isolated from the granulation tissue of a wound model (a polypropylene net inserted subcutaneously to rats) or intact rat skin. Collagen content was measured following the addition of different concentrations of histamine and treatment with histamine receptor antagonists (ketotifen - H1 inhibitor, ranitidine - H2 inhibitor) and a histamine receptor H1 agonist (2-pyridylethylamine dihydrochloride).The cells were identified as myofibroblasts: alpha-smooth muscle actin, vimentin, and desmin positive in all experimental conditions. Histamine increased the collagen level within both cell cultures, i.e., those isolated from granulation tissue or intact skin. It did not, however, influence the expression of either the collagen type I or III genes within the cultured myofibroblasts. Histamine activity was reduced by ketotifen (the H1 receptor inhibitor) and increased by the H1 receptor agonist, as demonstrated by changes in the levels of collagen in the myofibroblast culture. Histamine increased collagen content within the cultures, acting directly on myofibroblasts via H1 receptor stimulation.

A systematic review of cranioplasty material toxicity in human subjects

PURPOSE

Local and systemic toxic reactions to implanted materials can result in morbidities. However, little is reported about cranioplasty implants. Therefore, we performed a systematic review on the toxicity of different materials used for cranioplasty implants.

MATERIALS AND METHODS

A systematic search was conducted by browsing the Pubmed, Embase, and Cochrane Library databases. All human studies that identified toxic (aseptic) reactions to any types of material used as cranioplasty implants or onplants, published up to January 1, 2019, were included in the review.

RESULTS

Nineteen studies were identified. Collectively, 36 patients endured some type of toxic reaction to an implanted material. Eleven studies presented several types of toxicity for PMMA cranioplasties in several tissue types. One article highlighted the risk of neurotoxicity for PMMA cranioplasty. Three articles presented toxic reactions to calcium phosphate and titanium implants. Three additional articles presented toxic reactions to PEEK, polypropylene-polyester, and polyethylene.

CONCLUSION

All materials currently used for cranioplasty showed occasional toxicity and morbidities. Therefore, none can be considered completely biologically inert. We found that aseptic inflammatory reactions have been underreported in the literature due to a high incidence of infections with questionable evidence.

Urethral Diverticulum following Polypropylene Mesh Midurethral Slings: A Literature Review

Aims

It is currently unknown whether an association exists between polypropylene mesh and urethral diverticulum formation following placement of polypropylene midurethral slings (MUS) for the treatment of stress urinary incontinence (SUI). We aimed to examine the literature associating MUS with the occurrence of urethral diverticula.

Methods

Multiple online research databases, including PubMed, Google Scholar, EBSCOhost, and the Cochrane Library, were searched, from January 2019 to February 2019, for evidence related to the occurrence of urethral diverticula following polypropylene MUS procedures.

Results

Four case reports were published demonstrating the occurrence of urethral diverticula following the use of polypropylene mesh for surgical treatment of SUI. Subjects of these cases were menopausal and had an elevated body mass index (BMI), recurrent urinary tract infections (UTIs), autoimmune conditions, or prior pelvic floor surgeries. A thorough urologic workup, including imaging prior to sling placement, was not always performed.

Conclusion

No clear association exists between polypropylene MUS placement and subsequent urethral diverticulum formation. Factors that diminish polypropylene mesh biocompatibility include elevated BMI, menopause, recurrent UTIs, prior pelvic surgeries, and preexisting medical conditions. Symptoms associated with urethral diverticula should prompt a complete urologic workup prior to MUS placement.

Tobacco use, immunosuppressive, chronic pain, and psychiatric conditions are prevalent in women with symptomatic mesh complications undergoing mesh removal surgery

Purpose

To identify demographic and clinical characteristics of patients with symptomatic pelvic floor mesh complications who underwent mesh removal at our academic medical center. The secondary goal was to determine patient-reported outcomes after mesh removal.

Materials and Methods

We conducted a retrospective review of consecutive patients from 2011-2016 undergoing removal of mesh graft for treatment of symptomatic mesh-related complications. Patient demographics, comorbidities, symptoms, and mesh factors were evaluated. Outcomes after explant were determined by the Patient Global Impression of Improvement and a Likert satisfaction scale.

Results

One hundred fifty-six symptomatic patients underwent complete or partial pelvic floor mesh removal during the study period. Mid-urethral slings comprised 86% of explanted mesh grafts. Mesh exposure or erosion was identified in 72% of patients. Eighty-one percent of patients presented with pain, and 35% reported pain in the absence of exposure or erosion. Pre-operative comorbidities included psychiatric disease (54.5%), chronic pain (34.0%), irritable bowel syndrome (20.5%) and fibromyalgia (9.6%). Forty-three percent of patients reported current or past tobacco use. At mean follow-up of 14 months, 68% of responding patients reported improvement on the Patient Global Impression of Improvement after surgery.

Conclusions

This research identified tobacco use, and psychiatric, immunosuppressive, and chronic pain conditions as prevalent in this cohort of patients undergoing mesh removal. Surgical removal can improve presenting symptoms, including for patients with pain in the absence of other indications.

Autoinflammatory/autoimmunity syndrome induced by adjuvants (Shoenfeld's syndrome) in patients after a polypropylene mesh implantation

In both hernia repair and pelvic organ prolapse surgery, polypropylene (PP) meshes are increasingly used. Although these technologies offer tremendous clinical benefits, the efficacy of these implants can be hindered by the body's immunologic reaction to the implanted material. Undesirable local effects such as chronic pain have been extensively described. Systemic effects, however, are not yet reported. Because systemic effects after implantation of other biomaterials have been described, we evaluated patients with implanted PP meshes for signs and symptoms of biomaterial-related systemic illnesses. Patients referred to an Autoimmunity Clinic between January 2014 and December 2017 were analyzed. In 40 patients, mesh implants were present. These patients were evaluated for the development of a systemic illness. Thirty-two consecutive women and eight men were included in the current study. Median age at the time of operation was 49.5 years (range, 28-75 years). Eighteen patients had a hernia repair and 22 patients had a vaginal mesh implant. Thirty-nine of 40 patients presented with chronic fatigue, and 38 of 40 patients had myalgia or muscle weakness. In most patients, these symptoms started shortly after the operation. All patients fulfilled the diagnostic criteria for autoinflammatory/autoimmunity syndrome induced by adjuvants (ASIA). In addition, most patients reported localized pain and (often-invalidating) irritable bowel syndrome. One quarter of the patients had an immunodeficiency, whereas a diagnosis of well-established systemic and/or localized autoimmune diseases was made in 45% of patients. Importantly, 75% of patients had a pre-existing allergic disease. In 6 patients, the hernia mesh could be completely removed, thereby resulting in (partial) recovery of the systemic disease. In conclusion, 40 patients developed symptoms of a systemic illness after a mesh operation. All patients fulfilled the diagnostic criteria for ASIA. One quarter of the patients had an immunodeficiency, whereas in approximately half of the patients, an autoimmune disease developed. We postulate that PP mesh implants may increase the risk of developing (auto)immune diseases by acting as an adjuvant.