Skin as marker for collagen type I/III ratio in abdominal wall fascia

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 Rare Case of Penoscrotal Webbing and Extensive Hernias: An Anatomical Report With Genetic Insights

During a routine anatomical dissection of an 81-year-old male cadaver received through the Gift Body Program of Saint Louis University School of Medicine (SLU SOM), a massive bulging in the abdominal area was observed that was consistent with numerous hernia repairs noted in the donor's self-reported medical history. Gross anatomical dissection of the cadaveric body revealed extensive herniation of portions of the small intestine and peritoneal sac along the costal margin and extending to the left aspect of the abdomen. Additionally, an uncircumcised phallus was buried within the suprapubic fat pad and demonstrated simple, grade III penoscrotal webbing (PSW), creating an impression of micropenis presence. To gain additional insights into the current case, analysis of the coding regions (exomes) of DNA procured from the body for putative genetic variants was performed using next-generation sequencing (NGS) technology. This analysis revealed 110 rare (minor allele frequency (MAF) ≤ 0.01), pathologic/deleterious genetic mutations. The most relevant variants to this case were the ones associated with male sexual development, BMP1 and BMP4; connective tissue development, COL3A1 and COL5A3; cilia morphogenesis and function, DNAH5 and MAPK15; as well as hormonal homeostasis, ESR1. Direct involvement of BMP1 both in male sexual development and hernia genesis makes it a strong candidate for linking the two pathologies, PSW and multiple hernias, observed in the present case. Yet the presence of a group of mutated genes linked to myopathies (ITGA7, NRAP, POLM, SCN5A, XIRP2) and muscular dystrophy (ITGA7) raises a question about the involvement of these muscular pathologies in hernia genesis and unsuccessful hernia repairs associated with the current case.

Determination of thick and thin fibres distribution in Sunda porcupine dorsal skin (Hystrix javanica) using Picrosirius red staining

The complexity of the Sunda porcupine skin has become an important topic due to the unique characteristics of its quill follicles. The structure and chemical composition of the skin has affected many physiological and other conditions. Generally, quills are larger, stronger and stiffer than hair; therefore, the skin structure needs to adapt to support their physiology. The strength of the skin is determined by its collagen composition and arrangement; therefore, this study aims to analyse the composition and distribution of thick and thin fibres based on the specific characteristics of Sunda porcupine skin under polarized light using picrosirius red staining. The skin samples used were from the thoracodorsal and lumbosacral regions of eight Sunda porcupine adults. The histological staining was carried out using the picrosirius red method, while the samples were observed under a polarized light microscope and analysed with software. The results showed that the skin is composed of 36%-65% thick fibres, 20%-35% thin fibres and small amounts of other types with the lumbosacral region having higher compositions of thick and thin fibres than those in the thoracodorsal region. Furthermore, the thoracodorsal and lumbosacral regions have the highest composition of thick fibre in the deeper dermis and quill follicle, respectively. These demonstrated that the complexity of the skin structure of Sunda porcupine due to its quill derivates correlated with its collagen composition and distribution.

Newborn and elderly skin: two fragile skins at higher risk of pressure injury

Skin is a key organ maintaining internal homeostasis by performing many functions such as water loss prevention, body temperature regulation and protection from noxious substance absorption, microorganism intrusion and physical trauma. Skin ageing has been well studied and it is well known that physiological changes in the elderly result in higher skin fragility favouring the onset of skin diseases. For example, prolonged and/or high-intensity pressure may suppress local blood flow more easily, disturbing cell metabolism and inducing pressure injury (PI) formation. Pressure injuries (PIs) represent a significant problem worldwide and their prevalence remains too high. A higher PI prevalence is correlated with an elderly population. Newborn skin evolution has been less studied, but some data also report a higher PI prevalence in this population compared to older children, and several authors also consider this skin as physiologically fragile. In this review, we compare the characteristics of newborn and elderly skin in order to determine common features that may explain their fragility, especially regarding PI risk. We show that, despite differences in appearance, they share many common features leading to higher fragility to shear and pressure forces, not only at the structural level but also at the cellular and molecular level and in terms of physiology. Both newborn and elderly skin have: (i) a thinner epidermis; (ii) a thinner dermis containing a less-resistant collagen network, a higher collagen III:collagen I ratio and less elastin; (iii) a flatter dermal-epidermal junction (DEJ) with lower anchoring systems; and (iv) a thinner hypodermis, resulting in lower mechanical resistance to skin damage when pressure or shear forces are applied. At the molecular level, reduced expression of transforming growth factor β (TGFβ) and its receptor TGFβ receptor II (TβRII) is involved in the decreased production and/or increased degradation of various dermal extracellular matrix (ECM) components. Epidermal fragility also involves a higher skin pH which decreases the activity of key enzymes inducing ceramide deficiency and reduced barrier protection. This seems to be correlated with higher PI prevalence in some situations. Some data also suggest that stratum corneum (SC) dryness, which may disturb cell metabolism, also increases the risk of PI formation. Besides this structural fragility, several skin functions are also less efficient. Low applied pressures induce skin vessel vasodilation via a mechanism called pressure-induced vasodilation (PIV). Individuals lacking a normal PIV response show an early decrease in cutaneous blood flow in response to the application of very low pressures, reflecting vascular fragility of the skin that increases the risk of ulceration. Due to changes in endothelial function, skin PIV ability decreases during skin ageing, putting it at higher risk of PI formation. In newborns, some data lead us to hypothesize that the nitric oxide (NO) pathway is not fully functional at birth, which may partly explain the higher risk of PI formation in newborns. In the elderly, a lower PIV ability results from impaired functionality of skin innervation, in particular that of C-fibres which are involved in both touch and pain sensation and the PIV mechanism. In newborns, skin sensitivity differs from adults due to nerve system immaturity, but the role of this in PIV remains to be determined.

Analysis of tissue inflammatory response, fibroplasia, and foreign body reaction between the polyglactin suture of abdominal aponeurosis in rats and the intraperitoneal implant of polypropylene, polypropylene/polyglecaprone and polyester/porcine collagen meshes

Purpose

To compare tissue inflammatory response, foreign body reaction, fibroplasia, and proportion of type I/III collagen between closure of abdominal wall aponeurosis using polyglactin suture and intraperitoneal implant of polypropylene, polypropylene/polyglecaprone, and polyester/porcine collagen meshes to repair defects in the abdominal wall of rats.

Methods

Forty Wistar rats were placed in four groups, ten animals each, for the intraperitoneal implant of polypropylene, polypropylene/polyglecaprone, and polyester/porcine collagen meshes or suture with polyglactin (sham) after creation of defect in the abdominal wall. Twenty-one days later, histological analysis was performed after staining with hematoxylin-eosin and picrosirius red.

Results

The groups with meshes had a higher inflammation score (p < 0.05) and higher number of gigantocytes (p < 0.05) than the sham group, which had a better fibroplasia with a higher proportion of type I/III collagen than the tissue separating meshes (p < 0.05). There were no statistically significant differences between the three groups with meshes.

Conclusions

The intraperitoneal implant of polypropylene/polyglecaprone and polyester/porcine collagen meshes determined a more intense tissue inflammatory response with exuberant foreign body reaction, immature fibroplasia and low tissue proportion of type I/III collagen compared to suture with polyglactin of abdominal aponeurosis. However, there were no significant differences in relation to the polypropylene mesh group.

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.

Profile of collagen prolines level of anterior rectus sheath tissue in indirect inguinal hernia: A cross-sectional study

Introduction

A hernia is a protrusion of an organ or tissue through an abnormal anatomical channel or opening. Epidemiological data indicated an increased prevalence of inguinal hernias in patients with connective tissue diseases. The biomechanical strength of connective tissue is highly dependent on the constituent of the matrix, including collagen. Fibroblasts produce and secrete procollagen containing high concentrations of proline and lysine. Collagen integrity plays an essential role in preventing hernia formation in the abdominal wall. To investigate the relationship between collagen proline levels of the anterior rectus sheath tissue in patients with lateral inguinal hernias (indirect inguinal hernia).

Methods

The study participants consisted of 67 inguinal hernia patients. A sample of anterior rectus tissue was obtained at the time of surgery, then being washed in a PBS buffer (pH 7.4). The measurement of collagen proline levels was subsequently carried out with enzyme linked immunosorbent assay (ELISA).

Results

All study participants were male with mean age of 44 years, mean body mass index of 22.6 kg/m² and mean onset of events of 27 months. Study subjects with reducible, irreducible, and incarcerated hernias were 45.7% (44/67 cases), 14.9% (10/67) and 19.4% (13/67), respectively. The mean proline level of the study subjects was 9.20. Correlation tests showed a correlation of proline levels and age (p = 0.001), body mass index (p = 0.006), and the onset of events (p = 0.023). Meanwhile, correlation of proline levels and occupation (p = 0.235) and clinical degree (p = 0.164) were not statistically significant.

Conclusion

Presence if relationship between proline levels with age, and onset of incidence among indirect inguinal hernia patients.

•

Collagen is the main structural protein in the muscle wall layer.

•

Defects in collagenases will result in abnormal collagen synthesis leading to pathological collagen degradation.

•

Decreases in hydroxyproline and collagen were observed in the fascia and muscle tissue of patients with inguinal hernias.

•

There are a relationship between proline levels with age, and onset of incidence among indirect inguinal hernia.

The evaluation of functional small intestinal submucosa for abdominal wall defect repair in a rat model: Potent effect of sequential release of VEGF and TGF-β1 on host integration

Ineffective vessel penetration and extracellular matrix (ECM) remodeling are responsible for the failure of porcine small intestinal submucosa (SIS)-repaired abdominal wall defects. Combined growth factors could be used as directing signals in a nature-mimicking strategy to improve this repair through mesh functionalization. In this work, vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGF-β1) were incorporated into a silk fibroin membrane via coaxial aqueous electrospinning to exploit their benefits of biological interactions. The membrane was sandwiched into the SIS bilayer as a functional mesh to repair partial-thickness defects in a rat model. Membrane characterization demonstrated that the core-shell structure ensured the independent distribution and sequential release of two regulators and protection of their bioactivities, which were confirmed by cell viability and protein expression. The mesh was further assessed to facilitate vasculature formation and collagen secretion in vitro, and exhibited better host integration than VEGF- or TGF-β1-containing mesh and developed reinforced mechanical properties compared with the VEGF-containing mesh after 28 days in vivo. Determination of the underlying biological interactions revealed that rapid VEGF release promotes angiogenesis and collagen secretion but initially potentiates the inflammatory response. Sustained TGF-β1 release at relatively low concentrations promoted VEGF for vessel permeation and maturation and steadily induced ECM remodeling under milder foreign body reactions. The functionalization of SIS improves repair by sufficient integration with timely remodeling and helps elucidate the related regulatory interactions.

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 prospective randomized comparison of sexual function and semen analysis following laparoscopic totally extraperitoneal (TEP) and transabdominal pre-peritoneal (TAPP) inguinal hernia repair

BACKGROUND

With standardization of laparoscopic technique of groin hernia repair, the focus of surgical outcome has shifted to lesser studied parameters like sexual function and fertility.

METHODS

This prospective randomized study was conducted in a single surgical unit at a tertiary care hospital. A sample size of 144 was calculated with 72 in each group (Group 1 TEP and Group 2 TAPP). Primary outcomes measured included comparison of sexual function using BMFSI, qualitative semen analysis and ASA levels between patients undergoing TEP or TAPP repair. Semen analysis and ASA was measured pre-operatively and 3 months post-operatively.

RESULTS

A total of 145 patients were randomized into two groups, TAPP (73) and TEP (72) patients. Both the groups were comparable in terms of demographic profile and hernia characteristics with majority of the patients in both the groups having unilateral inguinal hernia (89.0% in TAPP group and 79.2% in TEP group). Both the groups showed statistically significant improvement in overall sexual function score (BMFSI) at 3 months; however, there was no inter group difference. Both the groups were also comparable in terms of ASA and qualitative semen analysis.

CONCLUSION

Both TEP and TAPP repair are comparable in terms of sexual function and effect on semen analysis. Laparoscopic repair improves the overall sexual functions in patients with groin hernia.

Morphological evaluation of polysaccharide content and collagen composition during cutaneous wound healing in the Sunda porcupine (Hystrix javanica)

Wound healing in the Sunda porcupine is believed to occur quickly, although the wound is large and severe. Wound enclosure involves many processes to restore the lost or damaged skin structure where conjugated polysaccharide-protein and collagen, as the main components deposited in wound tissue to restore it. The aim of this study was to evaluate alteration of polysaccharide contents and collagen in untreated full-thickness wound healing in the thoracodorsal and lumbosacral regions in the Sunda porcupines. Histological analysis was performed by periodic acid Schiff, alcian blue pH 2.5, picrosirius red staining method and Low Vacuum Scanning Electron Microscope (LV-SEM) imaging to obtain the fundamental data of healing process. Wound healing began with re-epithelization followed by progressive wound contraction with 4 overlapping stages in about 30–50 days until the wound closed (21–30 days in thoracodorsal and 30–50 days in lumbosacral). Neutral polysaccharide was more widely distributed compared to the acid polysaccharide in almost all stages of wound healing. The ratio of collagen I to III appeared to be higher in the thoracodorsal region than the lumbosacral region during healing process. LV-SEM imaging showed changes in connective tissue structure in the wound border and granulation tissue which appeared abundant and mixed of thin and thick fiber. In conclusion, cutaneous full thickness wound healing in the Sunda porcupine occurred faster in the thoracodorsal region, which might be correlated to the role of neutral polysaccharide and a high ratio of collagen I to III.

[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.

Local Growth Hormone Therapy for Pressure Ulcer Healing on a Human Skin Mouse Model

The growth hormone is involved in skin homeostasis and wound healing. We hypothesize whether it is possible to improve pressure ulcer (PU) healing by locally applying the recombinant human growth hormone (rhGH) in a human skin mouse model. Non-obese diabetic/severe combined immunodeficient mice (n = 10) were engrafted with a full-thickness human skin graft. After 60 days with stable grafts, human skin underwent three cycles of ischemia-reperfusion with a compression device to create a PU. Mice were classified into two groups: rhGH treatment group (n = 5) and control group (n = 5). In the rhGH group for local intradermal injections, each had 0.15 mg (0.5IU) applied to the PU edges, once per week for four weeks. Evaluation of the wound healing was conducted with photographic and visual assessments, and histological analysis was performed after complete wound healing. The results showed a healing rate twice as fast in the rhGH group compared to the control group (1.25 ± 0.33 mm2/day versus 0.61 ± 0.27 mm2/day; p-value < 0.05), with a faster healing rate during the first 30 days. The rhGH group showed thicker skin (1953 ± 457 µm versus 1060 ± 208 µm; p-value < 0.05) in the repaired area, with a significant decrease in collagen type I/III ratio at wound closure (62 days, range 60-70). Local administration of the rhGH accelerates PU healing in our model. The rhGH may have a clinical use in pressure ulcer treatment.

Lightweight Versus Heavyweight Mesh in Laparoscopic Inguinal Hernia Repair: An Updated Systematic Review and Meta-Analysis of Randomized Trials

Background: There is no consensus on whether lightweight mesh (LWM) is better than heavyweight mesh (HWM) in laparoscopic inguinal hernia repair (LIHR). This study aims to update the previous reviews and to analyze present randomized controlled studies comparing LWM versus HWM in LIHR systematically. Methods: We searched PubMed, Embase, and Cochrane Library for randomized controlled trials (RCTs), which compared LWM with HWM in adults with LIHR. All eligible data of outcomes were quantitatively analyzed using Revman 5.3 software or qualitatively described. The outcomes included chronic pain, moderate-severe chronic pain, recurrence, foreign body sensation, influence on sexual life and male fertility (pain with ejaculation, testicular pain, etc.). Results: We included 12 RCTs that analyzed 3092 hernias. The difference between LWM and HWM groups at any follow-up time was not significant in chronic pain and foreign body sensation. Compared with HWM group, patients in LWM group had a similar risk of postoperative moderate-severe chronic pain at 3 and 12 months follow-up, a slightly increased risk of developing moderate-severe chronic pain at >12 months follow-up (risk ratio [RR] = 3.20, 95% confidence interval [CI] 1.05-9.75, P = .04), and a higher risk of recurrence rate (RR = 2.28, 95% CI 1.17-4.44, P = .02). At long-term follow-up, the influences of LWM and HWM on sexual life and male fertility were comparable. Conclusion: LWMs do not show advantages in chronic pain, foreign body sensation as well as the influence on sexual life and male fertility, and may increase hernia recurrence rates for LIHR. In addition, a higher incremental cost and lower incremental effect of LWMs make conventional HWMs preferred choice for LIHR.

Dynamic changes of the extracellular matrix during corneal wound healing

The extracellular matrix (ECM) confers transparency to the cornea because of the precise organization of collagen fibrils and a wide variety of proteoglycans. We monitored the corneal wound healing process after alkali burns in rabbits. We analyzed the location and expression of collagens and proteoglycans, the clinical impact, and the recovery of optical transparency. After the animals received both general and ocular topical anesthesia, the central cornea of the left eye was burned by placing an 8-mm diameter filter paper soaked in 0.5 N NaOH for 60 s. The eyes were evaluated under a surgical microscope at 1, 3, and 6 months after burning. At each time point, the clinical conditions of the burned and control corneas were observed. The arrangement of collagen fibers in the corneal stroma was visualized by Picrosirius-red staining, Gomori's silver impregnation and transmission electronic microscopy. Corneal light transmittance was also measured. Myofibroblasts presence was analyzed by immunohistochemistry. mRNA expression levels of collagen types I and III, lumican, decorin, keratocan and alpha-smooth muscle actin were determined by quantitative real-time polymerase chain reaction. One month after alkali burn, the ECM was disorganized and filled with lacunae containing different types of cells and collagen type III fibers in the wound area. Corneal opacities were present with attendant loss of light transmittance. Collagen and proteoglycan mRNA expression levels were up-regulated. After three months, wound healing progress was indicated by reduced corneal opacity, increased light transmittance, reorganization of collagen fibers and only collagen type I expression levels were at control levels. After six months, the wound area ECM morphology was similar to controls, but transmittance values remained low, denoting incomplete restoration of the stromal architecture. This multidisciplinary study of the stromal wound healing process revealed changes in corneal transmittance, collagen organization, myofibroblasts presence and ECM composition at 1, 3, and 6 months after alkali burning. Documenting wound resolution during the six-month period provided reliable information that can be used to test new therapies.

Meta-Analysis of Randomized Controlled Trials Comparing Lightweight and Heavyweight Mesh for Laparoscopic Total Extraperitoneal Inguinal Hernia Repair

The aim of this study was to compare the outcomes of lightweight and heavyweight mesh on postoperative recovery in laparoscopic total extraperitoneal (TEP) inguinal hernia repair. PubMed, Embase, Science Citation Index, and the Cochrane Library were used to search for published clinical randomized controlled trials, which compared lightweight meshes with heavyweight meshes in TEP inguinal hernia repair. The outcomes were calculated as risk ratios with 95 per cent confidence intervals using RevMan 5.2. Eight randomized controlled trials were included. Compared with a heavyweight mesh, the lightweight mesh led to a higher incidence of recurrence (risk ratio = 2.52, 95% confidence interval 1.10–5.81; P = 0.03). There was no significant difference in chronic moderate to severe pain, foreign body sensation, and seroma. The use of lightweight mesh is not recommended for TEP inguinal hernia repair.

Integration of Biomechanical and Biological Characterization in the Development of Porous Poly(caprolactone)-Based Membranes for Abdominal Wall Hernia Treatment

Aims. Synthetic meshes are the long-standing choice for the clinical treatment of abdominal wall hernias: the associated long-term complications have stimulated the development of a new generation of bioresorbable prostheses. In this work, polycaprolactone (PCL) porous membranes prepared by solvent casting/porogen leaching of PCL/poly(ethylene glycol) (PEG) blends with different compositions (different PCL/PEG weight ratios and PEG molecular weights) were investigated to be applied in the field. An optimal porous membrane structure was selected based on the evaluation of physicochemical, biomechanical, and in vitro biological properties, compared to a reference commercially available hernia mesh (CMC). Findings. Selected PCL7-2i membranes, derived from PCL/PEG 70/30 (PCL: Mw 70,000-90,000 Da; PEG: 35,000 Da), showed suitable pore size for the application, intermediate surface hydrophilicity, and biomimetic mechanical properties. In vitro cell tests performed on PCL7-2i membranes showed their cytocompatibility, high cell growth during 21 days, a reduced production of proinflammatory IL-6 with respect to CMC, and a significant secretion of collagen type I. Conclusions. PCL7-2i membranes showed biomimetic biomechanical properties and in vitro biological properties similar to or even better than - in the case of anti-inflammatory behavior and collagen production - CMC, a commercially available product, suggesting potentially improved integration in the host tissue.

Incidence of and risk factors for incisional hernia after closure of temporary ileostomy for colorectal malignancy

PURPOSE

Incisional hernia is a major complication after stoma closure and can cause uncomfortable symptoms. In this study, we evaluated the risk factors for hernia formation with the aim of reducing the incidence of incisional hernia.

METHODS

A total of 134 oncology patients underwent closure of a temporary loop ileostomy between May 2004 and December 2013. The incidence of incisional hernia was determined by routine follow-up computed tomography scanning every 6 months. The relationships between patients' characteristics, including age, sex, obesity, diabetes mellitus, surgical site infection, chronic obstructive pulmonary disease, hypertension, hypoalbuminemia, smoking, and presence of a midline hernia and the occurrence of incisional hernia were retrospectively evaluated.

RESULTS

The median follow-up time was 47 months (range 8-130). Hernias occurred in 23.9% of patients (32/134). The median time to detection of hernias was 8 months (range 2-39). The Chi-squared test revealed significant differences in obesity (P = 0.0003), hypertension (P = 0.0057), and incisional hernia history (P = 0.0000) between patients with and without incisional hernia. Multivariable analysis and univariate analysis revealed that hypertension and the presence of midline incisional hernia were risk factors for incisional hernia.

CONCLUSIONS

Hypertension and the presence of a midline incisional hernia were the major risk factors for incisional hernia after loop ileostomy closure. These risk factors can be addressed before planning surgery.

Chitosan porous 3D scaffolds embedded with resolvin D1 to improve in vivo bone healing

The aim of this study was to investigate the effect chitosan (Ch) porous 3D scaffolds embedded with resolvin D1 (RvD1), an endogenous pro-resolving lipid mediator, on bone tissue healing. These scaffolds previous developed by us have demonstrated to have immunomodulatory properties namely in the modulation of the macrophage inflammatory phenotypic profile in an in vivo model of inflammation. Herein, results obtained in an in vivo rat femoral defect model demonstrated that two months after Ch + RvD1 scaffolds implantation, an increase in new bone formation, in bone trabecular thickness, and in collagen type I and Coll I/Coll III ratio were observed. These results suggest that Ch scaffolds embedded with RvD1 were able to lead to the formation of new bone with improvement of trabecular thickness. This study shows that the presence of RvD1 in the acute phase of the inflammatory response to the implanted biomaterial had a positive role in the subsequent bone tissue repair, thus demonstrating the importance of innovative approaches for the control of immune responses to biomedical implants in the design of advanced strategies for regenerative medicine. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1626-1633, 2018.

International guidelines for groin hernia management

INTRODUCTION

Worldwide, more than 20 million patients undergo groin hernia repair annually. The many different approaches, treatment indications and a significant array of techniques for groin hernia repair warrant guidelines to standardize care, minimize complications, and improve results. The main goal of these guidelines is to improve patient outcomes, specifically to decrease recurrence rates and reduce chronic pain, the most frequent problems following groin hernia repair. They have been endorsed by all five continental hernia societies, the International Endo Hernia Society and the European Association for Endoscopic Surgery.

METHODS

An expert group of international surgeons (the HerniaSurge Group) and one anesthesiologist pain expert was formed. The group consisted of members from all continents with specific experience in hernia-related research. Care was taken to include surgeons who perform different types of repair and had preferably performed research on groin hernia surgery. During the Group's first meeting, evidence-based medicine (EBM) training occurred and 166 key questions (KQ) were formulated. EBM rules were followed in complete literature searches (including a complete search by The Dutch Cochrane database) to January 1, 2015 and to July 1, 2015 for level 1 publications. The articles were scored by teams of two or three according to Oxford, SIGN and Grade methodologies. During five 2-day meetings, results were discussed with the working group members leading to 136 statements and 88 recommendations. Recommendations were graded as "strong" (recommendations) or "weak" (suggestions) and by consensus in some cases upgraded. In the Results and summary section below, the term "should" refers to a recommendation. The AGREE II instrument was used to validate the guidelines. An external review was performed by three international experts. They recommended the guidelines with high scores. The risk factors for inguinal hernia (IH) include: family history, previous contra-lateral hernia, male gender, age, abnormal collagen metabolism, prostatectomy, and low body mass index. Peri-operative risk factors for recurrence include poor surgical techniques, low surgical volumes, surgical inexperience and local anesthesia. These should be considered when treating IH patients. IH diagnosis can be confirmed by physical examination alone in the vast majority of patients with appropriate signs and symptoms. Rarely, ultrasound is necessary. Less commonly still, a dynamic MRI or CT scan or herniography may be needed. The EHS classification system is suggested to stratify IH patients for tailored treatment, research and audit. Symptomatic groin hernias should be treated surgically. Asymptomatic or minimally symptomatic male IH patients may be managed with "watchful waiting" since their risk of hernia-related emergencies is low. The majority of these individuals will eventually require surgery; therefore, surgical risks and the watchful waiting strategy should be discussed with patients. Surgical treatment should be tailored to the surgeon's expertise, patient- and hernia-related characteristics and local/national resources. Furthermore, patient health-related, life style and social factors should all influence the shared decision-making process leading up to hernia management. Mesh repair is recommended as first choice, either by an open procedure or a laparo-endoscopic repair technique. One standard repair technique for all groin hernias does not exist. It is recommended that surgeons/surgical services provide both anterior and posterior approach options. Lichtenstein and laparo-endoscopic repair are best evaluated. Many other techniques need further evaluation. Provided that resources and expertise are available, laparo-endoscopic techniques have faster recovery times, lower chronic pain risk and are cost effective. There is discussion concerning laparo-endoscopic management of potential bilateral hernias (occult hernia issue). After patient consent, during TAPP, the contra-lateral side should be inspected. This is not suggested during unilateral TEP repair. After appropriate discussions with patients concerning results tissue repair (first choice is the Shouldice technique) can be offered. Day surgery is recommended for the majority of groin hernia repair provided aftercare is organized. Surgeons should be aware of the intrinsic characteristics of the meshes they use. Use of so-called low-weight mesh may have slight short-term benefits like reduced postoperative pain and shorter convalescence, but are not associated with better longer-term outcomes like recurrence and chronic pain. Mesh selection on weight alone is not recommended. The incidence of erosion seems higher with plug versus flat mesh. It is suggested not to use plug repair techniques. The use of other implants to replace the standard flat mesh in the Lichtenstein technique is currently not recommended. In almost all cases, mesh fixation in TEP is unnecessary. In both TEP and TAPP it is recommended to fix mesh in M3 hernias (large medial) to reduce recurrence risk. Antibiotic prophylaxis in average-risk patients in low-risk environments is not recommended in open surgery. In laparo-endoscopic repair it is never recommended. Local anesthesia in open repair has many advantages, and its use is recommended provided the surgeon is experienced in this technique. General anesthesia is suggested over regional in patients aged 65 and older as it might be associated with fewer complications like myocardial infarction, pneumonia and thromboembolism. Perioperative field blocks and/or subfascial/subcutaneous infiltrations are recommended in all cases of open repair. Patients are recommended to resume normal activities without restrictions as soon as they feel comfortable. Provided expertise is available, it is suggested that women with groin hernias undergo laparo-endoscopic repair in order to decrease the risk of chronic pain and avoid missing a femoral hernia. Watchful waiting is suggested in pregnant women as groin swelling most often consists of self-limited round ligament varicosities. Timely mesh repair by a laparo-endoscopic approach is suggested for femoral hernias provided expertise is available. All complications of groin hernia management are discussed in an extensive chapter on the topic. Overall, the incidence of clinically significant chronic pain is in the 10-12% range, decreasing over time. Debilitating chronic pain affecting normal daily activities or work ranges from 0.5 to 6%. Chronic postoperative inguinal pain (CPIP) is defined as bothersome moderate pain impacting daily activities lasting at least 3 months postoperatively and decreasing over time. CPIP risk factors include: young age, female gender, high preoperative pain, early high postoperative pain, recurrent hernia and open repair. For CPIP the focus should be on nerve recognition in open surgery and, in selected cases, prophylactic pragmatic nerve resection (planned resection is not suggested). It is suggested that CPIP management be performed by multi-disciplinary teams. It is also suggested that CPIP be managed by a combination of pharmacological and interventional measures and, if this is unsuccessful, followed by, in selected cases (triple) neurectomy and (in selected cases) mesh removal. For recurrent hernia after anterior repair, posterior repair is recommended. If recurrence occurs after a posterior repair, an anterior repair is recommended. After a failed anterior and posterior approach, management by a specialist hernia surgeon is recommended. Risk factors for hernia incarceration/strangulation include: female gender, femoral hernia and a history of hospitalization related to groin hernia. It is suggested that treatment of emergencies be tailored according to patient- and hernia-related factors, local expertise and resources. Learning curves vary between different techniques. Probably about 100 supervised laparo-endoscopic repairs are needed to achieve the same results as open mesh surgery like Lichtenstein. It is suggested that case load per surgeon is more important than center volume. It is recommended that minimum requirements be developed to certify individuals as expert hernia surgeon. The same is true for the designation "Hernia Center". From a cost-effectiveness perspective, day-case laparoscopic IH repair with minimal use of disposables is recommended. The development and implementation of national groin hernia registries in every country (or region, in the case of small country populations) is suggested. They should include patient follow-up data and account for local healthcare structures. A dissemination and implementation plan of the guidelines will be developed by global (HerniaSurge), regional (international societies) and local (national chapters) initiatives through internet websites, social media and smartphone apps. An overarching plan to improve access to safe IH surgery in low-resource settings (LRSs) is needed. It is suggested that this plan contains simple guidelines and a sustainability strategy, independent of international aid. It is suggested that in LRSs the focus be on performing high-volume Lichtenstein repair under local anesthesia using low-cost mesh. Three chapters discuss future research, guidelines for general practitioners and guidelines for patients.

CONCLUSIONS

The HerniaSurge Group has developed these extensive and inclusive guidelines for the management of adult groin hernia patients. It is hoped that they will lead to better outcomes for groin hernia patients wherever they live. More knowledge, better training, national audit and specialization in groin hernia management will standardize care for these patients, lead to more effective and efficient healthcare and provide direction for future research.

Etiology of Inguinal Hernias: A Comprehensive Review

Background

The etiology of inguinal hernias remains uncertain even though the lifetime risk of developing an inguinal hernia is 27% for men and 3% for women. The aim was to summarize the evidence on hernia etiology, with focus on differences between lateral and medial hernias.

Results

Lateral and medial hernias seem to have common as well as different etiologies. A patent processus vaginalis and increased cumulative mechanical exposure are risk factors for lateral hernias. Patients with medial hernias seem to have a more profoundly altered connective tissue architecture and homeostasis compared with patients with lateral hernias. However, connective tissue alteration may play a role in development of both subtypes. Inguinal hernias have a hereditary component with a complex inheritance pattern, and inguinal hernia susceptible genes have been identified that also are involved in connective tissue homeostasis.

Conclusion

The etiology of lateral and medial hernias are at least partly different, but the final explanations are still lacking on certain areas. Further investigations of inguinal hernia genes may explain the altered connective tissue observed in patients with inguinal hernias. The precise mechanisms why processus vaginalis fails to obliterate in certain patients should also be clarified. Not all patients with a patent processus vaginalis develop a lateral hernia, but increased intraabdominal pressure appears to be a contributing factor.

Bilateral endoscopic totally extraperitoneal (TEP) inguinal hernia repair does not impair male fertility

PURPOSE

Endoscopic totally extraperitoneal (TEP) hernia repair with polypropylene mesh has become a well-established technique. However, since the mesh is placed in close contact with the spermatic cord, mesh-induced inflammation may affect its structures, possibly resulting in impaired fertility. The aim of this observational prospective cohort study was to assess fertility after bilateral endoscopic TEP inguinal hernia repair in male patients.

METHODS

Fifty-seven male patients (22-60 years old) with primary, reducible, bilateral inguinal hernias underwent elective bilateral endoscopic TEP hernia repair with use of polypropylene mesh. The primary outcome was testicular perfusion; secondary outcomes were testicular volume, endocrinological status, and semen quality. All patients were assessed preoperatively and 6 months postoperatively.

RESULTS

Follow-up was completed in 44 patients. No statistically significant differences in measurements of testicular blood flow parameters or testicular volume were found. Postoperative LH levels were significantly higher [preoperative median 4.3 IU/L (IQR 3.4-5.3) versus postoperative median 5.0 IU/L (IQR 3.6-6.5), p = 0.03]. Levels of inhibin B were significantly lower postoperatively [preoperative median 139.0 ng/L (IQR 106.5-183.0) versus postoperative median 27.0 ng/L (IQR 88.3-170.9), p = 0.01]. No significant changes in FSH or testosterone levels were observed. There were no differences in semen quality.

CONCLUSIONS

Our data suggest that bilateral endoscopic TEP hernia repair with polypropylene mesh does not impair fertility, as no differences in testicular blood flow, testicular volume, or semen quality were observed. Postoperative levels of LH and inhibin B differed significantly from preoperative measurements, yet no clinical relevance could be ascribed to these findings.

Hernias- Is it a primary defect or a systemic disorder? Role of collagen III in all hernias- A case control study

Introduction

The need of this study is to assess the role of collagen III in all hernias which include primary inguinal hernias ventral and recurrent abdominal hernias.

Collagen type III represents the mechanically instable, less cross-linked collagen synthesized during the early days of wound healing. Quantitative assessment of collagen III in scar tissue on transversalis fascia as tissue obtained from cases operated for various hernias and compared to that of patients operated for abdominal surgeries for indications other than hernia was compared.

Materials and methods

In this study we had a total of 90 patients, of which 45 patients underwent mesh repair for the various hernias and 45 patients who underwent laparotomies for various reasons were included as controls. Size of 1 × 1cm transversalis fascia was taken in both subjects and was sent for quantitative assessment using Immunohistochemistry test. All the above cases were randomized as per age,sex,BMI, co morbidities and materials used for repair.

Results

Results were analysed quantitatively and classified into following groups:Based on intensity of staining into Mild, Intermediate and Well stained and based on Quantity of Collagen III into Grade 0---NIL, Grade 1--1-25%, Grade 2-26-50%, Grade 3--51-75%, Grade 4--76-100% (Table 1). In the case group we had 52.4%,35.7% and 11.9% of the cases in Grade 4, Grade 3 and Grade 2 which proved that there was increased presence of Collagen 3, where as 84.4%,4.4% and 11.1% of patients in the control group were classified as Grade 1, Grade 2, Grade 0. For the quantitative study -Chi square test value −81.279 and the p value < 0.001. For the intensity of staining -Chi square test value −57.64 and p value is < 0.001.

Conclusion

This study signifies that ventral, recurrent and primary inguinal hernias are not just caused because of a primary defect but an acquired disorder with respect to collagen distribution.

•

Collagen III.

•

Quantitative study.

•

Grade and intensity of staining.

Experimental study of inflammatory response and collagen morphometry with different types of meshes

PURPOSE

To compare an inflammation score and collagen morphometry after incisional hernia repair with four different meshes at two time points.

METHODS

Four types of mesh were used to repair an abdominal wall incisional defect in Wistar rats: high-density polypropylene (HW/PP); low-density polypropylene (LW/PP); polypropylene mesh encapsulated with polydioxanone coated with oxidized cellulose (PP/CE); and expanded polytetrafluoroethylene (ePTFE). An inflammation score based on histological analysis and collagen morphometry was performed after 7 and 28 days after operation (POD).

RESULTS

Compared to LW/PP group at 7 POD, HW/PP group had lower (p = 0.014) and PP/CE group had higher inflammation scores (p = 0.001). At 28 POD, higher scores were seen in all the other groups compared to the LW/PP group (HW/PP, p = 0.046; PP/CE, p < 0.001; ePTFE, p = 0.027). Comparing groups individually at 7 and 28 PODs, all demonstrated lower inflammation score values at 28 POD (HW/PP, p < 0.001; LW/PP, p < 0.001; PP/CE, p = 0.002; ePTFE, p = 0.001). At 7 POD, higher amounts of collagen were detected in ePTFE compared to HW/PP (p < 0.001) and LW/PP (p = 0.004) and in PPCE group compared to HW/PP (p = 0.022). At 28 POD, no statistically significant difference was found. Comparing groups individually at 7 and 28 PODs, HW/PP and LW/PP showed larger amounts of collagen at the 28th POD, without any statistically significant differences for the PP/CE and ePTFE groups.

CONCLUSIONS

Inflammation scores decreased in all groups at 28 POD. Collagen deposition was higher for non-composite meshes at 28 POD.

Picrosirius red staining: a useful tool to appraise collagen networks in normal and pathological tissues

Specific staining of the extracellular matrix components is especially helpful in studying tissue remodeling, particularly in the case of connective tissue pathologies. As developed by Junqueira and colleagues in 1979, specific staining by Picrosirius red is one of the most important stains to study collagen networks in different tissues. Under polarized light, collagen bundles appear green, red or yellow, and are easily differentiated from the black background, thus allowing for quantitative morphometric analysis. As Junqueira and colleagues point out, many studies use color staining to differentiate collagen bundles and to specify collagen types, yet other studies report that polarized colors only reflect fiber thickness and packing. Using a simple histological example, our study illustrates the inability of Picrosirius red staining to differentiate collagen types, since the absorbed amount of polarized light by this dye strictly depends on the orientation of the collagen bundles.