Abdominal wall hernias-A local manifestation of systemically impaired quality of the extracellular matrix

Genetic and biologic risk factors associated with hernia formation: A review

BACKGROUND

This systematic review aims to identify genetic and biologic markers associated with abdominal hernia formation.

METHODS

Following PRIMSA-guidelines, we searched PubMed, MEDLINE, Embase, Scopus, and COCHRANE databases.

RESULTS

Of 5946 studies, 65 were selected, excluding parastomal hernias due to insufficient data. For inguinal hernias, five studies unveiled 92 susceptible loci across 66 genes, predominantly linked to immune responses. Eleven studies observed elevated MMP-2 levels, with seven highlighting greater MMP-2 in direct compared to indirect inguinal hernias. One incisional hernia study identified unique gene-expression profiles in 174 genes associated with inflammation and cell-adhesion. In hiatal hernias, several genetic risk loci were identified. For all hernia categories, type I/III collagen ratios diminished.

CONCLUSIONS

Biological markers in inguinal hernias appears consistent. Yet, the genetic predisposition in incisional hernias remains elusive. Further research to elucidate these genetic and biological intricacies can pave the way for more individualized patient care.

Effect of Functionalization of Texturized Polypropylene Surface by Silanization and HBII-RGD Attachment on Response of Primary Abdominal and Vaginal Fibroblasts

Soft tissue defects, such as incisional hernia or pelvic organ prolapse, are prevalent pathologies characterized by a tissue microenvironment rich in fragile and dysfunctional fibroblasts. Precision medicine could improve their surgical repair, currently based on polymeric materials. Nonetheless, biomaterial-triggered interventions need first a better understanding of the cell-material interfaces that truly consider the patients' biology. Few tools are available to study the interactions between polymers and dysfunctional soft tissue cells in vitro. Here, we propose polypropylene (PP) as a matrix to create microscale surfaces w/wo functionalization with an HBII-RGD molecule, a fibronectin fragment modified to include an RGD sequence for promoting cell attachment and differentiation. Metal mold surfaces were roughened by shot blasting with aluminum oxide, and polypropylene plates were obtained by injection molding. HBII-RGD was covalently attached by silanization. As a proof of concept, primary abdominal and vaginal wall fasciae fibroblasts from control patients were grown on the new surfaces. Tissue-specific significant differences in cell morphology, early adhesion and cytoskeletal structure were observed. Roughness and biofunctionalization parameters exerted unique and combinatorial effects that need further investigation. We conclude that the proposed model is effective and provides a new framework to inform the design of smart materials for the treatment of clinically compromised tissues.

Incisional Hernia: A Surgical Complication or Medical Disease?

Incisional hernia (IH) is a frequent complication following abdominal surgery. The development of IH could be more sophisticated than a simple anatomical failure of the abdominal wall. Reported IH incidence varies among studies. This review presented an overview of definitions, molecular basis, risk factors, incidence, clinical presentation, surgical techniques, postoperative care, cost, risk prediction tools, and proposed preventative measures. A literature search of PubMed was conducted to include high-quality studies on IH. The incidence of IH depends on the primary surgical pathology, incision site and extent, associated medical comorbidities, and risk factors. The review highlighted inherent and modifiable risk factors. The disorganisation of the extracellular matrix, defective fibroblast functions, and ratio variations of different collagen types are implicated in molecular mechanisms. Elective repair of IH alleviates symptoms, prevents complications, and improves the quality of life (QOL). Recent studies introduced risk prediction tools to implement preventative measures, including suture line reinforcement or prophylactic mesh application in high-risk groups. Elective repair improves QOL and prevents sinister outcomes associated with emergency IH repair. The watchful wait strategy should be reviewed, and options should be discussed thoroughly during patients' counselling. Risk stratification tools for predicting IH would help adopt prophylactic measures.

Collagen remodelling and plasma ascorbic acid levels in patients suspected of inherited bleeding disorders harbouring germline variants in collagen-related genes

Introduction

Variants in collagen‐related genes COL1A1, COL3A1, COL5A1 and COL5A2 are associated with Ehlers‐Danlos syndrome (EDS), a heterogeneous group of connective tissue disorders strongly associated with increased bleeding. Of patients with incompletely explained bleeding diathesis, a relatively high proportion were shown to harbour at least one heterozygous variant of unknown significance (VUS) in one of these genes, the vast majority without meeting the clinical criteria for EDS.

Aim

To investigate the functional consequences of the identified variants by assessing the formation and degradation of types I, III and V collagen, in addition to plasma levels of ascorbic acid (AA).

Methods

A total of 31 patients harbouring at least one heterozygous VUS in COL1A1, COL3A1, COL5A1 or COL5A2 and 20 healthy controls were assessed using monoclonal antibodies targeting neo‐epitopes specific for collagen formation and degradation. Plasma AA levels were measured in patients using high‐performance liquid chromatography.

Results

Serum levels of C5 M (degradation of type V collagen) were decreased in patients compared with healthy controls (p = .033). No significant differences were found in biomarkers for remodelling of types I and III collagen. A significant negative correlation between bleeding (ISTH‐BAT score) and plasma AA levels was shown (r = −.42; r² = .17; p = .020). Suboptimal or marginally deficient AA status was found in 8/31 patients (26%).

Conclusion

Functional investigations of collagen remodelling were not able to identify any clear associations between the identified variants and increased bleeding. The negative correlation between plasma AA levels and ISTH‐BAT score motivates further investigations.

Systemic biomarkers currently implicated in the formation of abdominal wall hernia: A systematic review of the literature

BACKGROUND

Surgery to the abdominal wall is ubiquitous worldwide and hernia treatment is challenging and expensive, posing a critical need to tailor treatment to individual patient risk-factors. In this systematic review, we consider specific systemic factors with potential as biomarkers of hernia formation.

METHODS

A healthcare database-assisted search, following PRISMA guidelines, identified journal articles for inclusion and analysis.

RESULTS

14 biomarker studies were selected, comparing hernia patients and hernia-free controls, focusing on markers of extracellular matrix (ECM) remodelling and collagen turnover. Matrix metalloproteinase-2 was increased in patients with inguinal hernia. Markers of type IV collagen synthesis were increased in patients with abdominal wall hernia; while markers of fibrillar collagen synthesis were reduced. Additional other ECM signalling proteins differ significantly within published studies.

CONCLUSION

We identify a lack of high-quality evidence of systemic biomarkers in tailoring treatment strategies relative to patient-specific risks, but recognise the potential held within biomarker-based diagnostic studies to improve management of hernia pathogeneses.

[Ventral hernias and extracellular matrix of connective tissue]

Ventral hernia is still one of the most common reason for scheduled and emergency surgery. The review is designed to reveal relationships between metabolism in extracellular matrix of connective tissue and pathogenesis of ventral hernias. These data will be valuable to develop a personalized approach to the treatment of these patients.

Decreased collagen type III synthesis in skin fibroblasts is associated with parastomal hernia following colostomy

Parastomal hernia (PH) is a common complication following stoma formation. Abnormal collagen synthesis has been suggested to be involved in PH. The aim of the present study is to explore the effect and mechanism of the collagen synthesis on PH. Data from 157 patients with rectal cancer who received permanent colostomy were retrospectively collected and analyzed to identify the risk factors for PH. Primary culture of skin fibroblasts from patients with or without PH were performed. Cell viability, migration and invasion levels were detected by Cell Counting Kit‑8, and wound healing and Transwell assays, respectively. Reverse transcription quantitative polymerase chain reaction and western blot analysis assays were performed to measure the gene and protein expression levels, respectively. The risk factors of sex, body mass index, aperture size and collagen expression were closely associated with the occurrence of PH. α1 (III) procollagen expression levels were significantly increased in patients with PH, while no marked difference in α1 (I) procollagen mRNA expression levels were observed in patients with or without PH. The viability and motility of fibroblasts from the patients with hernia were suppressed. The expression levels of matrix metalloproteinase (MMP)‑2 and MMP‑9 were decreased while the levels of collagen III and metalloproteinase inhibitor 1 (TIMP‑1) were increased in the fibroblasts from the patients with PH. Silencing TIMP‑1 expression promoted fibroblast migration and invasion and reversed the patterns of MMP‑2, MMP‑9 and collagen III expression in fibroblasts from the patients with PH. Decreased collagen III may inhibit the development of PH, potentially through decreases in TIMP‑1 expression. Therefore, the results from the present study may provide a novel target for PH therapy.

Diverticulosis and nine connective tissue disorders: epidemiological support for an association

Purpose: An underlying connective tissue disorder (CTD) may predispose to formation of intestinal diverticula. We assess the association of diverticulosis with nine selected CTDs, to inform the pathophysiology of diverticula. Methods: A population-based period-prevalence study. Individuals (3.5 million New Zealand residents born 1901-1986) with a health system record 1999-2016 were grouped into those with a hospital diagnosis of diverticulosis or diverticulitis (ICD-10-AM K57), and those without. Also recorded were any hospital diagnoses of nine selected CTDs. The association of exposure to diverticulosis and each CTD was assessed using logistic regressions adjusted for age, gender, ethnicity and region. Results: In all, 85,958 (2.4%) people had a hospital diagnosis of diverticulosis. Hospitalisation with diverticulosis was highly significantly associated with rectal prolapse (adjusted odds ratio [OR] = 3.9), polycystic kidney disease (OR = 3.8), heritable syndromes (Marfan or Ehlers-Danlos) (OR = 2.4), female genital prolapse (OR = 2.3), non-aortic aneurysm (OR = 2.3), aortic aneurysm (OR = 2.2), inguinal hernia (OR = 1.9) and dislocations of shoulder and other joints (OR = 1.7), but not subarachnoid haemorrhage (OR = 1.0). Conclusion: People with diverticulosis are more likely to have colonic extracellular matrix (ECM)/connective tissue alterations in anatomical areas other than the bowel, suggesting linked ECM/connective tissue pathology. Although biases may exist, the results indicate large-scale integrated studies are needed to investigate underlying genetic pathophysiology of colonic diverticula, together with fundamental biological studies to investigate cellular phenotypes and ECM changes.

Association of Primary Ventral Hernia and Pregnancy

OBJECTIVE

To determine the optimal timing of elective repair, the primary objective of this study was to assess if parity at the time of repair and subsequent pregnancy were associated with reoperation for recurrence. The secondary objective was to examine if parity was associated with hernia formation requiring surgical repair.

SUMMARY BACKGROUND DATA

Women of childbearing age constitute 18% of patients operated on for a primary ventral hernia, but consensus is lacking on the management in women who might subsequently become pregnant.

METHODS

In this nationwide retrospective cohort-study, all women born in Denmark from 1962 to 1971 were eligible for inclusion and followed from age 15 to 45 years. The follow-up rate was 100%. Data on pregnancies and surgical procedures were obtained from the Danish Medical Birth Registry and National Patient Registry. Extended Cox regression and Poisson regression were used for statistical analysis.

RESULTS

In total, 470,646 women were included, of whom 2113 underwent repair of a primary ventral hernia. The 10-year cumulative incidence of reoperation for recurrence was 14.1% (95% CI 12.3%-16.0%). Parity at the time of repair was not associated with reoperation for recurrence, while a subsequent pregnancy was associated with a 1.6-fold increased risk (hazard ratio 1.58, 95% CI 1.08-2.31). Parous women had a 7-fold increased risk of undergoing hernia repair compared with nulliparous, in an age-adjusted model (incidence rate ratio 7.04, 95% CI 5.87-8.43).

CONCLUSION

To reduce the risk of hernia recurrence, the optimal timing of elective repair is after the last pregnancy.

Molecular Mechanisms and Potential Therapeutic Targets in Incisional Hernia

The pathophysiology underlying the formation, progression, and surgical healing of incisional hernia (IH) that develops as a major complication associated with abdominal laparotomy is poorly understood. The proposed mechanisms include the switch of collagen phenotype and the proliferation of abnormal fibroblasts after surgery. The focus of this article was to critically review the cellular, biochemical, and potential molecular events associated with the development of IH. The disturbance in collagen homeostasis with alterations in the expression of collagen subtypes, including type 1, type 3, type 4, and type 5, and impairment in the transdifferentiation of fibroblasts to myofibroblasts are discussed. The phenotype switch of wound-repair fibroblasts results in mechanically compromised extracellular matrix that triggers the proliferation of abnormal fibroblasts. High-mobility group box 1 could be involved in wound progression, whereas signaling events mediated by tumor necrosis factor β1, connective tissue growth factor, lysyl oxidase, and hypoxia-inducible factor 1 play significant role in the wound healing response. Thus, the ratio of tumor necrosis factorβ1: high-mobility group box 1 could be a critical determinant of the underlying pathology. Potential target sites for therapeutic intervention in the management of IH are recognized.

Systematic review and network meta-analysis of methods of mesh fixation during laparoscopic ventral hernia repair

BACKGROUND

Ventral hernia repairs are common and have high recurrence rates. They are usually repaired laparoscopically with an intraperitoneal mesh, which can be fixed in various ways. The aim was to evaluate the recurrence rates for the different fixation techniques.

METHODS

This systematic review included studies with human adults with a ventral hernia repaired with an intraperitoneal onlay mesh. The outcome was recurrence at least 6 months after operation. Cohort studies with 50 or more participants and all RCTs were included. PubMed, Embase and the Cochrane Library were searched on 22 September 2016. RCTs were assessed with the Cochrane risk-of-bias assessment tool and cohort studies with the Newcastle-Ottawa scale. Studies comparing fixation techniques were included in a network meta-analysis, which allowed comparison of more than two fixation techniques.

RESULTS

Fifty-one studies with a total of 6553 participants were included. The overall crude recurrence rates with the various fixation techniques were: absorbable tacks, 17·5 per cent (2 treatment groups); absorbable tacks with sutures, 0·7 per cent (3); permanent tacks, 7·7 per cent (20); permanent tacks with sutures, 6·0 per cent (25); and sutures, 1·5 per cent (6). Six studies were included in a network meta-analysis, which favoured fixation with sutures. Although statistical significance was not achieved, there was a 93 per cent chance of sutures being better than one of the other methods.

CONCLUSION

Both crude recurrence rates and the network meta-analysis favoured fixation with sutures during laparoscopic ventral hernia repair.