The effect of surgery on the levels of matrix metalloproteinases in patients with inguinal hernia

A Comprehensive Review of Inguinal Hernia Occurrence in Obese Individuals

Inguinal hernia repair is one of the most commonly performed surgical activities worldwide. Given the circumstances, understanding and identifying the risk and the protective factors is an essential step in order to prevent, diagnose and treat such a common condition. For a long time, obesity was generally considered to be a risk factor in the occurrence of an inguinal hernia. Studies have provided some unexpected data, suggesting that it might actually be a protective factor. This review aims to provide an overview on this topic, taking into account systemic aspects such as collagen distribution and metabolism. In inguinal hernia patients, the ratio between type I collagen and type III collagen is decreased, with type III collagen being responsible for the weakness of the abdominal wall. In obese patients, the extracellular matrix becomes richer in collagen, especially type I collagen, which will generate strength and stiffness. Obesity seems to be a protective factor indeed, but in order to understand the underlying mechanism and to choose the optimal surgical approach, further research is needed.

A Systematic Review on the Role of Matrix Metalloproteinases in the Pathogenesis of Inguinal Hernias

The recurrence rate in patients who undergo surgery for abdominal wall hernias (AWHs) is high. AWHs have been hypothesized to be a disease of the extracellular matrix, which is supported by evidence showing a high incidence of AWHs in patients with connective tissue disorders. This study aimed to investigate the most recent literature studies describing the levels of several matrix metalloproteinases (MMPs) in the blood and fascia, with the objective of better clarifying the pathogenetic role of matrix metalloproteinases (MMPs) and their inhibitors in inguinal hernias (IHs). A systematic literature search was conducted using the PubMed, Scopus, and Web of Science electronic databases to identify eligible studies. The identified studies were included in the analysis, and a qualitative synthesis of the results is provided to describe the most recent findings. Seventeen studies were included. An association between MMP-2 and direct IHs has also been demonstrated. MMP-1, MMP-2, MMP-9, MMP-12, and MMP-13 levels were increased in both the serum and fascia of patients with IHs. The analysis of inhibitors showed an increase in tissue inhibitors of metalloproteinases (TIMPs), specifically TIMP-1 in IHs, particularly in direct hernias, and a reduction in TIMP-2 in the biopsy samples of the transversalis fascia. In contrast, a reduction in TIMP-1 and an increase in TIMP-2 levels have been reported only in the serum of patients with IHs. Metalloproteinases play a crucial role in the pathogenesis of IHs. The analysis of other molecules, such as TIMPs or their correlation with specific genes, is enhancing our understanding of the pathophysiology of IHs. However, more prospective studies, including comprehensive clinical and laboratory data collection, are required to confirm the relationship between the studied biomarkers and the risk of IHs.

Alarmins and Related Molecules in Elective Surgery

Surgery is associated with alterations of alarmins' and related molecules' levels. The aim of this study was to investigate which biomarkers are most involved in surgery. The studied group consisted of 58 patients with inguinal or umbilical hernia or cholecystolithiasis and 21 healthy controls for compa-rison. We also added seven acute patients with appendicitis, cholecystitis and incarcerated hernia. Serum concentrations of soluble receptor of advanced glycation end-products (sRAGE), extracellular newly identified receptor for advanced glycation end-products binding protein (EN-RAGE), calprotectin, high mobility group box 1 (HMGB1) and interleukin 6 (IL-6) were analysed by ELISA before and after surgery. Preoperative concentrations of calprotectin were significantly decreased while concentrations of sRAGE were significantly increased in patients compared to controls; the concentrations of EN-RAGE and HMGB1 did not differ significantly. IL-6 levels were undetectable in elective patients preoperatively and in controls. Postoperatively, there was a significant increase of EN-RAGE, calprotectin, HMGB1, and IL-6 and a significant decrease of sRAGE compared to preoperative levels. In acute patients, all tested molecules except for sRAGE were significantly increased preoperatively, and sRAGE was significantly decreased. In contrast, after surgery, we could observe a further increase in IL-6; the other biomarkers did not differ significantly. We can conclude that the concentrations of all tested biomarkers are significantly influenced by elective surgery. The postoperative levels of all tested molecules increase except for sRAGE, whose level is significantly decreased after surgery. In acute states, these molecules are already increased, and the influence of surgery is, apart from IL-6, insignificant.