Circulating levels of matrix metalloproteinases and tissue inhibitors of metalloproteinases in patients with incisional 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.

Biological processes and factors involved in soft and hard tissue healing

Wound healing is a complex and iterative process involving myriad cellular and biologic processes that are highly regulated to allow satisfactory repair and regeneration of damaged tissues. This review is intended to be an introductory chapter in a volume focusing on the use of platelet concentrates for tissue regeneration. In order to fully appreciate the clinical utility of these preparations, a sound understanding of the processes and factors involved in soft and hard tissue healing. This encompasses an appreciation of the cellular and biological mediators of both soft and hard tissues in general as well as specific consideration of the periodontal tissues. In light of good advances in this basic knowledge, there have been improvements in clinical strategies and therapeutic management of wound repair and regeneration. The use of platelet concentrates for tissue regeneration offers one such strategy and is based on the principles of cellular and biologic principles of wound repair discussed in this review.

The role of tissue inhibitor of metalloproteinases in the aetiology of inguinal and incisional hernias

Inguinal and incisional hernias are the two most common types of hernias caused by abdominal wall weakness and defects in connective tissue. The structure of the extracellular matrix, mainly collagen and metalloproteinases (MMPs), and their regulators have been studied extensively and found to play a significant role in the pathophysiology of hernias. One of the regulators of MMPs, tissue inhibitor metalloproteinases (TIMPs), bind to MMPs and inhibit its activity significantly shifting the balance towards collagen synthesis rather than degradation. Due to their importance in collagen metabolism, their metabolism might be significant in the aetiology of hernias. Our study used immunohistochemical techniques to investigate the possible effects of TIMP 1 and 2 on the samples taken from the abdominal walls of patients with inguinal and incisional hernias, compared them with control patients, and reviewed the literature. In this study, samples of 90 patients (30 patients from control, inguinal hernia, and incisional hernia groups) were taken and analysed. These samples were stained with TIMP-1 Ab-2 and TIMP2 Ab-5 (Clone 3A4) antibodies and evaluated under ×100 magnification. The degree of staining was classified as (a): No staining (0), (b): Staining less than 10% (I), (c): Staining between 10% and 50% (II), (d): Staining more than 50% (III). Statistical analyses were done. No significant difference was found between groups in terms of patient demographics. Smoking and family history of hernia was not found to be associated with TIMP expression. TIMP1 expression was significantly higher in the incisional and inguinal hernia group than in the control group (P < .05), while the level of TIMP2 was higher in the control group. (P < .05). TIMP1 and TIMP2 levels did not significantly differ between incisional and inguinal hernia groups. We found significantly increased TIMP-1 levels in tissue samples from patients with hernia supporting its suggested role in hernia pathophysiology. Local alterations in MMP and TIMP levels might play a role in the pathogenesis of hernias. Thus detection of TIMP in tissues can be important for clinical use after further validation studies. In the era of molecular medicine, detecting TIMP levels in hernia patients can impact clinical practice.

A Human Cellular Model for Colorectal Anastomotic Repair: The Effect of Localization and Transforming Growth Factor-β1 Treatment on Collagen Deposition and Biomarkers

Anastomotic leakage (AL) is a devastating complication after colorectal surgery, possibly due to the loss of stabilizing collagen fibers in the submucosa. Our aim was to assess the formation of collagen in the colon versus the rectum with or without transforming growth factor (TGF)-β1 exposure in a human cellular model of colorectal repair. Primary fibroblasts were isolated by an explant procedure from clinically resected tissue rings during anastomosis construction in 19 consecutive colorectal patients who underwent laparoscopy. The cells, identified as fibroblasts by morphologic characteristics and flow cytometry analysis (CD90⁺), were cultured for 8 days and in 12 patients in the presence of 1 ng/mL TGF-β1. Total collagen deposition was measured colorimetrically after Sirius red staining of fixed cell layers, and type I, III, and VI collagen biosynthesis and degradation were specifically determined by the biomarkers PINP, PRO-C3, PRO-C6, and C3M in conditioned media by competitive enzyme-linked immunosorbent assays. Total collagen deposition by fibroblasts from the colon and rectum did not significantly differ. TGF-β1 treatment increased PINP, PRO-C6, and total collagen deposition. Mechanistically, TGF-β1 treatment increased COL1A1 and ACTA2 (encoding α-smooth muscle actin), and decreased COL6A1 and MMP2 mRNA levels in colorectal fibroblasts. In conclusion, we found no effect of anatomic localization on collagen production by fibroblasts derived from the large intestine. TGF-β1 represents a potential therapeutic agent for the prevention of AL by increasing type I collagen synthesis and collagen deposition.

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.

Matrix Metalloproteinase-3 is Key Effector of TNF-α-Induced Collagen Degradation in Skin

Inflammatory processes in the skin augment collagen degradation due to the up-regulation of matrix metalloproteinases (MMPs). The aim of the present project was to study the specific impact of MMP-3 on collagen loss in skin and its interplay with the collagenase MMP-13 under inflammatory conditions mimicked by the addition of the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α). Skin explants from MMP-3 knock-out (KO) mice or from transgenic (TG) mice overexpressing MMP-3 in the skin and their respective wild-type counterparts (WT and WTT) were incubated ex vivo for eight days. The rate of collagen degradation, measured by released hydroxyproline, was reduced (p < 0.001) in KO skin explants compared to WT control skin but did not differ (p = 0.47) between TG and WTT skin. Treatment with the MMP inhibitor GM6001 reduced hydroxyproline media levels from WT, WTT and TG but not from KO skin explants. TNF-α increased collagen degradation in the WT group (p = 0.0001) only. More of the active form of MMP-13 was observed in the three MMP-3 expressing groups (co-incubation with receptor-associated protein stabilized MMP-13 subforms and enhanced detection in the media). In summary, the innate level of MMP-3 seems responsible for the accelerated loss of cutaneous collagen under inflammatory conditions, possibly via MMP-13 in mice.

Uncontrolled gelatin degradation in non-healing chronic wounds

OBJECTIVE

To compare matrix metalloproteinase (MMP)-9 and the antiproteinase tissue inhibitor of metalloproteinases (TIMP)-1 in wound fluids and sera from patients with chronic non-healing or acute healing wounds. In addition, the functional consequences on MMP-9 activity and general gelatinase activity were assessed.

METHOD

In this observational study, samples were collected from patients with venous leg ulcers (VLUs), patients with type 2 diabetes with neuropathic foot ulcers (DFUs), and from another cohort of VLU patients with sterile split-thickness skin graft donor sites after autologous skin grafting, serving as healing control wounds. MMP-9 and TIMP-1 concentrations were determined by enzyme-linked immunosorbent assays. MMP-9 and gelatinase activities were determined in wound fluids in subsets of the patients.

RESULTS

A total of 24 patients took part in the study. No significant differences in MMP-9 wound fluid levels were found among the three groups. TIMP-1 levels were markedly and significantly lower in the two chronic wound groups resulting in a severely unbalanced MMP-9/TIMP-1 ratio, especially notable in the VLU group and possibly in the elevated endogenous MMP-9 activity (p<0.01) compared with the acute wound fluids. At least 20% of the chronic wound fluids displayed atypical patterns on gelatin zymography and showed high general gelatinase activity that was not inhibited by either TIMP-1 or by a gelatinase inhibitor (AG3340). MMP-9 levels were higher in the sera of the patients with type 2 diabetes.

CONCLUSION

We hypothesise that non-MMP proteinases contribute to matrix destruction in a significant number of chronic wounds. Blocking the excessive MMP-9 activity may be insufficient to normalise wound healing. The reasons and effects of the very low TIMP-1 levels in chronic wounds need further clarification.

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.

Novel understanding of high mobility group box-1 in the immunopathogenesis of incisional hernias

Introduction: Incisional hernias (IH) arise as a complication of patients undergoing laparotomy. Current literature has assessed the role of extracellular matrix (ECM) disorganization, alterations in type I and type III collagen, matrix metalloproteinases, and tissue inhibitors of metalloproteases on IH. However, there is limited information on the underlying molecular mechanisms that lead to ECM disorganization. Areas covered: We critically reviewed the literature surrounding IH and ECM disorganization and offer a novel pathway that may be the underlying mechanism resulting in ECM disorganization and the immunopathogenesis of IH. Expert opinion: High mobility group box-1 (HMGB-1), a damage-associated molecular pattern, plays an important role in the sterile inflammatory pathway and has been linked to ECM disorganization and the triggering of the NLRP3 inflammasome. Further research to investigate the role of HMGB-1 in the molecular pathogenesis of IH would be critical in identifying novel therapeutic targets in the management of IH formation.

Incisional hernias following open gynecological surgery: a population-based study

Introduction

Incisional hernia is a common and costly complication following abdominal surgery. The incidence of incisional hernia after gynecological surgery is not as well studied as that after general surgery.

Materials and methods

The Swedish National Quality Register for Gynecological Surgery (GynOp) collects preoperative, intraoperative, and postoperative information regarding gynecological surgery. Data were extracted from 2006 to 2014. The National Patient Register (NPR) contains physicians’ data from both public and private hospitals. Univariate and multivariate Cox proportional hazard analyzes were performed on risk factors.

Results

Between 2006 and 2014, 39,312 women undergoing open surgery were registered in GynOp. The NPR recorded 526 patients who were diagnosed with or had undergone surgery for incisional hernia. The mean follow-up was 2.8 years. Five years after surgery the cumulative incidence of incisional hernias was 2.0% (95% confidence interval 1.8–2.2%). In multivariate Cox proportional hazard analysis obesity (BMI > 30), age > 60 years, midline incision, smoking, kidney, liver, and pulmonary disease were found to predict an increased risk for incisional hernias (all p < 0.05).

Conclusions

There is much to be gained if the patient can cease smoking and lose weight before undergoing abdominal surgery. The Pfannenstiel incision results in fewer incisional hernias and should be considered whenever possible.

Activity of metalloproteinases and adiponectin in obese patients-a possible factor of incisional hernias after bariatric procedures

PURPOSE

Metalloproteinases are a key component of the pathogenesis of abdominal hernias. Obesity is considered a risk factor in herniogenesis and hernia recurrence. The aim of this study was to evaluate the serum concentrations of metalloproteinase-2 (MMP-2), MMP-9, MMP-13, and adiponectin in morbidly obese and non-overweight controls.

MATERIALS AND METHODS

The participants were recruited from among patients undergoing bariatric and non-bariatric surgery and divided into two groups: I (body mass index (BMI)≥35 kg/m², n=40) and II (BMI<25 kg/m², n=30). Serum concentrations of MMP-2, MMP-9, MMP-13, and adiponectin were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

A statistically significant difference between groups was observed for MMP-2 concentration. The median MMP-9 concentration was higher in the obese group, but the difference was not statistically significant. Median MMP-13 concentrations did not differ between groups. Serum adiponectin concentration was insignificantly higher in the non-obese group.

CONCLUSIONS

The elevated serum MMP-2 and MMP-9 concentrations in obese individuals may be related to the higher incidence of incisional hernias in this population.

Metalloproteinases and Their Inhibitors in Patients with Inguinal Hernia

AIM

The aim of this prospective study is to investigate if there is a relationship between inguinal hernia, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs).

MATERIALS AND METHODS

This case control study was performed on patients admitted to the general surgery department of Erzincan University Hospital. Four groups were created: control, indirect hernia, direct hernia, and bilateral hernia. All groups were comprised of 11 patients. Serum and tissue levels of MMP-1, MMP-2, MMP-9, MMP-13, TIMP-1, TIMP-2, TIMP-3, and hydroxyproline were evaluated.

RESULTS

MMPs values were significantly high at hernia groups, especially at bilateral hernia group (p < 0.05), whereas TIMPs values were significantly low at bilateral hernia group (p < 0.05). MMPs values were increasing at hernia groups in an order as control, indirect, direct, and bilateral. TIMPs values were decreasing at hernia groups in an order as control, indirect, direct, and bilateral.

CONCLUSION

Increased levels of MMP-1-2-9-13 and decreased levels of TIMP-1-2-3 may have played role in the formation of inguinal hernia. Hernia is not only a local defect, but a reflection of systemic disease. This is even more significant for bilateral hernias.

Risk Factors for the Development of an Incisional Hernia after Sigmoid Resection for Diverticulitis: An Analysis of 33 Patient, Operative and Disease-associated Factors

Incisional hernia (IH) is a relatively common sequelae of sigmoidectomy for diverticulitis. The aim of this study was to investigate factors that may predict IH in diverticulitis patients. Two hundred and one diverticulitis patients undergoing sigmoidectomy between January 2002 and December 2012 were identified (mean follow-up 5.15 ± 2.33 years). Patients with wound infections were excluded. Thirteen patient-associated, three diverticular disease-related, and 17 operative variables were evaluated in patients with and without IH. Volumetric fat was measured on pre-operative CTs. Fischer's exact, χ2, and Mann–Whitney tests and multivariate regression analysis were used for statistics. Thirty-four (17%) patients had an IH. On multivariate analysis, wound packing (OR 3.4, P = 0.017), postoperative nonwound infection (OR 7.4, P = 0.014), and previous hernia (OR 3.6, P = 0.005) were as independent predictors of IH. Fifteen of 34 (44%) patients who developed a hernia had a history of prior hernia. Of 33 potential risk factors analyzed, including smoking, chronic obstructive pulmonary disease, and obesity, the only patient factor present preoperatively associated with increased risk of a postsigmoidectomy hernia after multivariate analysis was a history of a previous hernia. Preoperative identification of patients with a history of hernia offers the opportunity to employ measures to decrease the likelihood of IH.

Tumor necrosis factor-α-accelerated degradation of type I collagen in human skin is associated with elevated matrix metalloproteinase (MMP)-1 and MMP-3 ex vivo

Tumor necrosis factor (TNF)-α induces matrix metalloproteinases (MMPs) that may disrupt skin integrity. We have investigated the effects and mechanisms of exogenous TNF-α on collagen degradation by incubating human skin explants in defined serum-free media with or without TNF-α (10 ng/ml) in the absence or presence of the nonselective MMP inhibitor GM6001 for 8 days. The basal culture conditions promoted type I collagen catabolism that was accelerated by TNF-α (p < 0.005) and accomplished by MMPs (p < 0.005). Levels of the collagenases MMP-8 and MMP-13 were insignificant and neither MMP-2 nor MMP-14 were associated with increased collagen degradation. TNF-α increased secretion of MMP-1 (p < 0.01) but had no impact on MMP-1 quantities in the tissue. Immunohistochemical analysis confirmed similar tissue MMP-1 expression with or without TNF-α with epidermis being the major source of MMP-1. Increased tissue-derived collagenolytic activity with TNF-α exposure was blocked by neutralizing MMP-1 monoclonal antibody and was not due to down-regulation of tissue inhibitor of metalloproteinase-1. TNF-α increased production (p < 0.01), tissue levels (p < 0.005) and catalytic activity of the endogenous MMP-1 activator MMP-3. Type I collagen degradation correlated with MMP-3 tissue levels (r_s = 0.68, p < 0.05) and was attenuated with selective MMP-3 inhibitor. Type I collagen formation was down-regulated in cultured compared with native skin explants but was not reduced further by TNF-α. TNF-α had no significant effect on epidermal apoptosis. Our data indicate that TNF-α augments collagenolytic activity of MMP-1, possibly through up-regulation of MMP-3 leading to gradual loss of type I collagen in human skin.