Genetic analysis of the TBX2 gene promoter in indirect inguinal hernia

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.

A Comprehensive Review: Molecular and Genetic Background of Indirect Inguinal Hernias

Background

The occurrence of indirect inguinal hernias (IIH) is 5 times more prevalent than that of direct inguinal hernias (IH) and it is 7 times more common in males, owing to the attendance of the processus vaginalis (PV) throughout testicular descent.

Summary

In children, the immense mainstream of IH is indirect. The progress of IIH development in children is instigated with a patent PV, which is mostly treated by simple herniorrhaphy. Syndromes of the collagen, microfibril, elastin, and glycosaminoglycan constituents of the extracellular matrix may attend to the development of IH. Our recent research showed that the lack of epithelial-mesenchymal transition (EMT) in children contributes to the development of IIH, while the scenario is defined as the opposite in adults. However, there is still a lack of knowledge on all of the genetic and molecular causes of the disease.

Key Messages

Here we aimed to review the published genetic background of IH, the deficiencies of connective tissue causing the disease, recently defined molecular pathways involved including EMT, and possible recurrence reasons. This comprehensive study can deliver an analytic outline aiding to define patients with IH combined with fundamental genetic diseases.

Susceptibility loci and polygenic architecture highlight population specific and common genetic features in inguinal hernias: genetics in inguinal hernias

BACKGROUND

The underlying pathology of inguinal hernia is still not fully known; thus, further investigations of genetic backgrounds is needed. Here, we aimed to identify genetic factors attributing to inguinal hernias and explore the polygenic architecture of which some components are population-specific, while others are more common among populations.

METHODS

We performed a genome-wide association study (GWAS) on subjects with inguinal hernias using BioBank Japan (BBJ) data with 1,983 cases and 172,507 controls, followed by a trans-ethnic meta-analysis with UK Biobank (UKBB) data. We performed downstream analyses in order to identify the mechanisms underlying inguinal hernias supported by genetic findings.

FINDINGS

We identified a locus closest to ELN, which encodes elastin, at the GWAS significant level. The trans-ethnic meta-analysis revealed 23 additional significant loci, including five loci newly identified not significant in BBJ or UKBB GWAS: TGFB2, RNA5SP214/VGLL2, LOC646588, HMCN2, and ATP5F1CP1/CDKN3. Downstream analyses revealed the overlap of GWAS significant signals in extracellular components, including elastin fiber formation. We also found a highly shared polygenic architecture across different populations (trans-ethnic genetic-effect correlation = 0•77, standard error = 0•26) and population-specific lead variants in ELN, indicating the critical role of elastin in inguinal hernias.

INTERPRETATION

We identified a significant locus of the ELN gene in the Japanese population and five additional loci across different populations. Downstream analyses revealed highly shared genetic architectures across populations and highlighted the important roles of extracellular components in the development of inguinal hernias. These findings deepen our understanding of the mechanisms underlying inguinal hernia.

FUNDING

The Japan Agency for Medical Research and Development (AMED) (Grant Number: JP19km0605001).

Matrix Metalloproteinases (MMP-2) and Tissue Inhibitors of Metalloproteinases (TIMP-2) in Patients with Inguinal Hernias

BACKGROUND

The development of inguinal hernia might be related with collagen metabolism, which was regulated by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). The aim of this study was to evaluate the mRNA and protein expression levels of MMP-2 and TIMP-2 in anterior rectus sheath fascia to investigate the function of them in inguinal hernia formation.

METHODS

The study enrolled 48 primary inguinal hernia patients: 32 participants had indirect inguinal hernia and 16 patients suffered direct inguinal hernia. Specimens were taken from the anterior rectus sheath fascia. The amounts of MMP-2 mRNA and TIMP-2 mRNA were evaluated by real-time fluorescence quantitative polymerase chain reaction (RT-PCR), and immunohistochemistry was performed to assess the protein expression of them.

RESULTS

The mRNA and protein expression levels of MMP-2 in direct group were significantly higher than those of control group (P < 0.05) and indirect group (P < 0.05), while the expression levels of TIMP-2 in direct group were significantly lower than those of control group (P < 0.05) and indirect group (P < 0.05). The ratio of MMP-2 mRNA/TIMP-2 mRNA in direct group was significantly higher than that of control group (P < 0.05) and indirect group (P < 0.05), and the ratio of indirect group was significantly higher than that of control group (P < 0.05). According to receiver operating characteristic (ROC) curve, MMP-2/TIMP-2 can diagnose direct hernia from controls with area under the curve (AUC) of 0.950 and indirect hernia with AUC of 0.730 effectively.

CONCLUSIONS

Elevated level of MMP-2 and decreased level of TIMP-2 may play a role in direct inguinal hernia development. The ratio of MMP-2/TIMP-2 may be useful in identification of direct hernia.

A network analysis revealed the essential and common downstream proteins related to inguinal hernia

Although more than 1 in 4 men develop symptomatic inguinal hernia during their lifetime, the molecular mechanism behind inguinal hernia remains unknown. Here, we explored the protein-protein interaction network built on known inguinal hernia-causative genes to identify essential and common downstream proteins for inguinal hernia formation. We discovered that PIK3R1, PTPN11, TGFBR1, CDC42, SOS1, and KRAS were the most essential inguinal hernia-causative proteins and UBC, GRB2, CTNNB1, HSP90AA1, CBL, PLCG1, and CRK were listed as the most commonly-involved downstream proteins. In addition, the transmembrane receptor protein tyrosine kinase signaling pathway was the most frequently found inguinal hernia-related pathway. Our in silico approach was able to uncover a novel molecular mechanism underlying inguinal hernia formation by identifying inguinal hernia-related essential proteins and potential common downstream proteins of inguinal hernia-causative proteins.

Hernia and Cancer: The Points Where the Roads Intersect

Introduction: This review aimed to present common points, intersections, and potential interactions or mutual effects for hernia and cancer. Besides direct relationships, indirect connections, and possible involvements were searched. Materials and Methods: A literature search of PubMed database was performed in July 2018 as well as a search of relevant journals and reference lists. The total number of screened articles was 1,422. Some articles were found in multiple different searches. A last PubMed search was performed during manuscript writing in December 2018 to update the knowledge. Eventually 427 articles with full text were evaluated, and 264 included, in this review. Results: There is no real evidence for a possible common etiology for abdominal wall hernias and any cancer type. The two different diseases had been found to have some common points in the studies on genes, integrins, and biomarkers, however, to date no meaningful relationship has been identified between these points. There is also some, albeit rather conflicting, evidence for inguinal hernia being a possible risk factor for testicular cancer. Neoadjuvant or adjuvant therapeutic modalities like chemotherapy and radiotherapy may cause postoperative herniation with their adverse effects on tissue repair. Certain specific substances like bevacizumab may cause more serious complications and interfere with hernia repair. There are only two articles in PubMed directly related to the topic of "hernia and cancer." In one of these the authors claimed that there was no association between cancer development and hernia repair with mesh. The other article reported two cases of squamous-cell carcinoma developed secondary to longstanding mesh infections. Conclusion: As expected, the relationship between abdominal wall hernias and cancer is weak. Hernia repair with mesh does not cause cancer, there is only one case report on cancer development following a longstanding prosthetic material infections. However, there are some intersection points between these two disease groups which are worthy of research in the future.

Increased incidence of inguinal hernia in offspring of female survivors of childhood central nervous system tumors

Female survivors of childhood central nervous system (CNS) tumors experience an increased risk of infertility and various pregnancy complications. We aimed to explore whether the incidence of inguinal hernia could be higher in offspring of female CNS tumor survivors as compared to the general population. Girls who were younger than 15 years of age and diagnosed with CNS tumors between 1958 and 2013 were identified from the Swedish Cancer Registry. By linking with the Swedish Medical Birth Registry, we identified 580 children who were born to mothers of CNS tumor survivors. After 9,662 person-years of follow-up, 23 of them were diagnosed with inguinal hernia, giving an incidence rate (IR) of 2.4 per 1,000 person-years, whereas the IR was 1.2 for the matched controls. Cox regression analysis was used to calculate the hazard ratio (HR) of inguinal hernia. After adjusting for some confounding factors, the incidence of inguinal hernia was significantly increased with an HR of 1.92 (95%CI 1.08-3.41). The association was predominant in offspring whose mothers were diagnosed with CNS tumors at the age of 10 and older, and with CNS tumors located in the brain.

Whole-exome sequencing identifies a potential TTN mutation in a multiplex family with inguinal hernia

Purpose

Inguinal hernia repair is one of the most common procedures in general surgery. Males are seven times more likely than females to develop a hernia and have a 27 % lifetime ‘risk’ of inguinal hernia repair. Several studies have demonstrated that a positive family history is an important risk factor for the development of primary inguinal hernia, which indicates that genetic factors may play important roles in the etiology of the disease. So far, the contribution of genetic factors and underlying mechanisms for inguinal hernia remain largely unknown. The aim of this study was to investigate a multiplex Estonian family with inguinal hernia across four generations.

Methods

The whole-exome sequencing was carried out in three affected family members and subsequent mutation screening using Sanger sequencing was performed in ten family members (six affected and four unaffected).

Results

Whole-exome sequencing in three affected family members revealed a heterozygous missense mutation c.88880A>C (p.Lys29627Thr; RefSeq NM_001256850.1) in the highly conserved myosin-binding A-band of the TTN gene. Sanger sequencing demonstrated that this mutation cosegregated with the disease in this family and was not present in ethnically matched control subjects.

Conclusion

We report that missense variant in the A-band of TTN is the strongest candidate mutation for autosomal-dominant inguinal hernia with incomplete penetrance.

Electronic supplementary material

The online version of this article (doi:10.1007/s10029-016-1491-9) contains supplementary material, which is available to authorized users.

A genome-wide association study identifies four novel susceptibility loci underlying inguinal hernia

Inguinal hernia repair is one of the most commonly performed operations in the world, yet little is known about the genetic mechanisms that predispose individuals to develop inguinal hernias. We perform a genome-wide association analysis of surgically confirmed inguinal hernias in 72,805 subjects (5,295 cases and 67,510 controls) and confirm top associations in an independent cohort of 92,444 subjects with self-reported hernia repair surgeries (9,701 cases and 82,743 controls). We identify four novel inguinal hernia susceptibility loci in the regions of EFEMP1, WT1, EBF2 and ADAMTS6. Moreover, we observe expression of all four genes in mouse connective tissue and network analyses show an important role for two of these genes (EFEMP1 and WT1) in connective tissue maintenance/homoeostasis. Our findings provide insight into the aetiology of hernia development and highlight genetic pathways for studies of hernia development and its treatment.

Inguinal hernia has high lifetime prevalence, especially in men. This genome-wide association study identifies 4 loci to be associated with inguinal hernia, and shows expression of nearby genes in mouse connective tissues.