Circulating matrix metalloproteinases and procollagen propeptides in 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.

Decellularization of Dense Regular Connective Tissue-Cellular and Molecular Modification with Applications in Regenerative Medicine

Healing of dense regular connective tissue, due to a high fiber-to-cell ratio and low metabolic activity and regeneration potential, frequently requires surgical implantation or reconstruction with high risk of reinjury. An alternative to synthetic implants is using bioscaffolds obtained through decellularization, a process where the aim is to extract cells from the tissue while preserving the tissue-specific native molecular structure of the ECM. Proteins, lipids, nucleic acids and other various extracellular molecules are largely involved in differentiation, proliferation, vascularization and collagen fibers deposit, making them the crucial processes in tissue regeneration. Because of the multiple possible forms of cell extraction, there is no standardized protocol in dense regular connective tissue (DRCT). Many modifications of the structure, shape and composition of the bioscaffold have also been described to improve the therapeutic result following the implantation of decellularized connective tissue. The available data provide a valuable source of crucial information. However, the wide spectrum of decellularization makes it important to understand the key aspects of bioscaffolds relative to their potential use in tissue regeneration.

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.

Risk of incisional hernia repair in patients with inflammatory bowel disease

AIM

Patients with inflammatory bowel disease (IBD) may undergo several abdominal surgeries with a risk of incisional hernia repair (IHR). The objectives of this study were to establish the risk of IHR and to analyse predictors of IHR after a first-time abdominal surgery for IBD.

METHOD

This Danish nationwide register-based cohort study (1996-2018) followed IBD patients from index operation until the date of IHR. The absolute risk was calculated as the cumulative incidence proportion treating death as a competing risk. Cox proportional hazard regression was used to compare the risk of IHR among different subtypes of IBD and to explore predictors of IHR. IBD subtypes were classified as ulcerative colitis (UC), Crohn's disease (CD) or unclassified IBD (IBD-U).

RESULTS

In total, 10 130 patients with IBD (UC 3911 [39%]; CD 4210 [41%]; IBD-U 2009 [20%]) underwent either an open or a laparoscopic index operation. The 10-year cumulative incidence of IHR varied between 5.0% and 6.3%, with a significantly higher risk in patients with UC and IBD-U. Patients with UC (75.9%) and IBD-U (91.9%) had more (two or more) abdominal surgeries in the follow-up period compared with CD (51.9%). The risk of IHR increased dramatically with the number of surgeries, although not as markedly if a laparoscopic approach was used. Male sex, age, comorbidity, fascial dehiscence, wound infection and presence of stoma were predictors of IHR for patients with IBD.

CONCLUSION

The long-term risk of IHR was roughly 5%-6%, with a higher risk in patients with UC and IBD-U. Open surgical approach and number of previous surgeries were, among other things, important predictors of IHR.

Inguinal hernia – epidemiology, risk factors, treatment methods (literature review)

Inguinal hernias (IH) are widespread in the human population and occur in 27–43 % of men and 3–6 % of women. Many risk factors for IH have been overestimated in the last decade: male gender is considered the leading factor (the ratio between men and women is approximately 1:7), less significant factors are heredity (most significant for women), physical activity (more significant for men), age (peak prevalence of IH occurs at 5 years and 70–80 years), congenital or acquired connective tissue dysplasia, history of prostatectomy, low body mass index.Hernioplasty with the use of synthetic mesh prostheses remains the most popular technique for surgical correction of IH. Performing non-prosthetic hernioplasty is only recommended if mesh prostheses are not available, for example in poor countries. In open hernioplasty using mesh prostheses, different methods are used today: Plug & Patch, Prolene Hernia System, Parietene Progrip, sutureless plastic according to Trabucco, Stoppa, preperitoneal techniques TIPP (trans-inguinal pre-peritoneal), TREPP (transrectus pre-peritoneal), TEP (total extraperitoneal), however, none of them showed significant advantages over the gold standard of open hernioplasty – tensionfree repair according to Liechtenstein.Laparoscopic IH correction is represented by the TAPP (transabdominal preperitoneal) technique, performed through the abdominal cavity, and TEP (total extraperitoneal) – extraperitoneal prosthetic hernioplasty. None of them has a significant advantage in the treatment of IH; therefore, when choosing a treatment method, the surgeon should be guided by the cost of the operation and the level of proficiency in one or another hernioplasty technique.

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

Matrix metalloproteinases (MMPs) are associated with the alteration of extracellular matrix. The purpose of this study was to investigate how the levels of matrix metalloproteinases and their inhibitors - TIMPs are influenced by the presence of inguinal hernia as well as by its surgical treatment. The studied group consisted of 25 patients with inguinal hernia and 21 healthy controls for comparison. Two blood samples - before and after the treatment were collected from patients. Serum concentrations of MMPs and TIMPs were analysed by multiplex immunoassays. There was a difference in circulating levels of MMPs in patients before the surgery compared to healthy controls - the concentrations of MMP-2 and MMP-9 were significantly lower (p=0.026, p=0.018, respectively). After the surgery, the levels of MMPs, especially MMP-2 (p<0.0001), were significantly decreased in patients compared to the preoperative values, apart from MMP-9. On the contrary, MMP-9 showed significant increase after the surgery (p<0.0001). Circulation levels of TIMP-2 in patients were significantly decreased in comparison with controls (p=0.004), whereas levels of TIMP-1 were similar to controls. Both tested metalloproteinase inhibitors showed a significant decrease in detected levels (TIMP-1 p=0.0004; TIMP-2 p<0.0001) after the procedure compared to the preoperative values. The levels of MMPs, especially MMP-2 and MMP-9, and their inhibitors TIMP-1 and TIMP-2 are involved by the presence of inguinal hernia as well as are influenced by the surgery.

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.

Comparative study of collagen and elastin content of abdominal wall fascia in inguinal hernia and non-hernia patients in an African population

PURPOSE

Altered composition of collagen and elastin in abdominal fascia has been linked with the pathogenesis of hernias. This has not been studied amongst Africans who have hernia presentations which vary significantly from Caucasian cohorts. The aim of this study was to determine, and compare, the collagen and elastin contents of the transversalis fascia and rectus sheath of inguinal hernia patients with non-hernia controls.

METHODS

Twenty-five patients with solitary, primary, uncomplicated inguinal hernia and twenty-five non-hernia controls were evaluated. Biopsies of the transversalis fascia and anterior rectus sheath were stained with Masson Trichrome and Verhöeff van-Gieson to isolate collagen and elastin respectively, which were quantified using the ImageJ/Fiji® image analysis software.

RESULTS

Inguinal hernia patients were aged 19-85 years with a mean age of 45.2 years, mean body mass index (BMI) of 23.3 kg/m² and mean duration of hernia of 42.5 months. Lateral hernias with no hernia defect or posterior wall defect [PL0] were the predominant clinical type. There were significantly lower collagen and higher elastin content in the transversalis fascia and rectus sheath of inguinal hernia patients [P < 0.001]. Regression analysis identified smoking and long duration of hernias as independent predictors of low collagen levels in this study CONCLUSION: Inguinal hernia patients in the study population demonstrated depleted collagen in the connective tissue of the inguinal canal. This might justify the routine use of prosthetic mesh for the reinforcement of the posterior wall during hernia repair.

Multinutrient Supplementation Increases Collagen Synthesis during Early Wound Repair in a Randomized Controlled Trial in Patients with Inguinal Hernia

BACKGROUND

Inguinal hernia disease is associated with an imbalanced collagen metabolism. Surgical stress has a negative impact on nutrients important for collagen synthesis.

OBJECTIVE

We hypothesized that supplementation with a combination of nutrients would enhance collagen biosynthesis in inguinal hernia disease patients when undergoing hernia repair.

METHODS

In this exploratory randomized controlled trial, 21 men (age: 55.2 ± 2.8 y; BMI: 25.0 ± 0.7 kg/m2) scheduled for Lichtenstein inguinal hernia repair were assigned to multinutrient supplementation (n = 10; multinutrient group) or no multinutrient supplementation (n = 11; control group). The multinutrient group received 14 g l-arginine, 14 g l-glutamine, 1250 mg vitamin C, and 55 mg zinc daily starting 14 d before surgery and ending 14 d after surgery. The multinutrient and control groups received high-quality protein to ensure a daily intake of 1.5 g protein/kg. Collagen biosynthesis was measured by the biomarkers type I procollagen propeptide (CICP), type III procollagen propeptide (PRO-C3), and type V procollagen propeptide (PRO-C5) in the sera on days -14, 0, and 1, and in the wound fluids on postoperative days 1 and 2. Compliance was recorded after the 28-d intervention period.

RESULTS

Serum PRO-C5 concentrations decreased (P < 0.05) postoperatively in the control but not the multinutrient group. Neither CICP nor PRO-C3 serum concentrations differed significantly between the 2 groups. In wound fluid, the CICP concentrations increased (P < 0.05) from days 1 to 2 in the multinutrient group and were 49% higher (P = 0.10) than those in the control group on day 2. Wound fluid concentrations PRO-C3 and PRO-C5 showed no significant time or group differences. The 28-d compliance was similar (P = 0.27) in the 2 groups.

CONCLUSION

Oral supplementation with arginine, glutamine, vitamin C, and zinc augment collagen synthesis during the first 2 d after inguinal hernia repair. This trial was registered at clinicaltrials.gov as NCT03221686.

Correlation of Baseline Plasma and Inguinal Connective Tissue Metalloproteinases and Their Inhibitors With Late High-Pressure Endoleak After Endovascular Aneurysm Repair: Long-term Results

Purpose: To investigate whether plasma and connective tissue matrix metalloproteinases (MMP) and their inhibitors (TIMP) may predict late high-pressure endoleak after endovascular aneurysm repair (EVAR). Materials and Methods: Samples of inguinal fascia and blood were collected in 72 consecutive patients (mean age 73.1 years; 68 men) undergoing primary EVAR with the Endurant stent-graft. Baseline plasma levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 and baseline MMP-2 and MMP-9 activity estimated using gelatin zymography (GZ) were compared between patients who developed late endoleak in follow-up and those who did not. Subgroup analyses were performed between patients with (n=18) and without inguinal hernias and between patients with moderate-diameter (50–59 mm; n=45) or large-diameter (≥60 mm; n=27) abdominal aortic aneurysms (AAA) at primary EVAR. Results: The mean follow-up period was 63.1 months (range 7.5–91.5), during which time 13 (18.1%) patients developed type I (6 Ia and 5 Ib) or 2 type III endoleaks. Only GZ-analyzed proMMP-9 concentrations were higher in the endoleak group than in patients without endoleak (mean difference 8.44, 95% CI −19.653 to −1.087, p=0.03). The patients with primary inguinal hernia at presentation had significantly higher tissue TIMP-2 values (0.8±0.7 vs 0.5±0.4, p=0.018) but lower plasma total (pro- + active) MMP-9 values (11.9±7.8 vs 16.2±7.4, p=0.042) than patients without hernias at the time of EVAR. Patients with AAAs ≥60 mm had significantly higher mean tissue homogenate levels of total (pro- + active) MMP-9 (p=0.025) and total (pro- + active) MMP-2 (p=0.049) as well as higher proMMP-9 (p=0.018) and total (pro- + active) MMP-9 (p=0.021) levels based on GZ compared to patients with moderate-diameter AAAs. Regression analysis revealed a significant association between total (pro- + active) MMP-9 plasma samples and the presence of hernia (OR 0.899, 95% CI 0.817 to 0.989, p=0.029) and between GZ-analyzed proMMP-9 and late endoleak (OR 1.055, 95% CI 1.007 to 1.106, p=0.025). GZ-analyzed proMMP-9 and active MMP-9 were strong predictors of late endoleak in patients with hernia (p=0.012 and p=0.044, respectively) and in patients with AAAs ≥60 mm (p=0.018 and p=0.041 respectively). Conclusion: Inguinal fascial tissue proMMP-9 significantly predicted late endoleak. ProMMP-9 and active MMP-9 biomarkers are significantly associated with late endoleak in hernia patients and in patients with AAAs ≥60 mm. Considering the clinical association between hernia and AAA and the fact that the AAA wall connective tissue environment remains exposed to systemic circulation after EVAR, inguinal fascia extracellular matrix dysregulation and altered MMP activity may reflect similar changes in AAA biology, leading to complications such as endoleak.