Peritoneal Regeneration Research Articles

DETERMINATION OF HYALURONIC ACID AND N-PEPTIDE OF COLLAGEN TYPE III LEVELS IN SERUM AS PREDICTORS OF THE PERITONEAL ADHESIONS DEVELOPMENT IN CHILDREN

Introduction. Adhesive peritoneal disease (APD) is the most common and formidable complication of abdominalsurgery, which led to adhesive processing occurring in 70 to 90 % of operated patients. It is manifested by lateadhesion intestinal obstruction (LAIO), chronic abdominal pain, constipation and infertility.The aim of the study was to investigate the levels of hyaluronic acid (HA) and N-peptide collagen type III (N-PCIII) in serum to determine the course of APD in children.Material and methods. Serum levels of HA and N-PC type III were determined in 148 children aged 6-17 years (83boys and 65 girls). I group (main) – 38 patients with APD, LAIO treatment with the use solution of natrii hyaluronasand decamethoxine, II comparison group – 35 children with APD, LAIO treatment by traditional methods, III group – 45patients operated on for other acute surgical pathologies of GI tract in which after surgery for 5-10 years no signsof APD were noted. The control group consisted of 30 children operated on inguinal hernias.All parents were given informed voluntary written consent to conduct the research. Statistical processing of theobtained results was performed using Microsoft Office Excel and Statistica 10.0 (StatSoft Inc.).Results. An increase in HA level in the control, main and comparative groups on the 5th day of postoperative periodwas registered by 31,94, 126,96 and 39,60%, respectively, in comparison with the preoperative values; on the 14th daydecrease in HA level was observed in all groups, by 21,24, 32,79 and 25,83%, respectively, in comparison with the 5th day.Determination of the level of N-PC type III in all groups showed an increase in its number on the 5th day,compared with pre-surgery by 64.62, 57.40 and 79.32 %, respectively. On the 14th day the level was 2 times higher inthe main group and 2.86 times higher in the comparison group, compared with the control indicators. This indicatedthe stabilization of connective tissue organization and peritoneal regeneration in the main group and the lack of clearperitoneal regeneration in the comparison group.Conclusions.1. Serum levels of HA and N-PC type III may be markers of the onset and development of APD in children.2. An increase in the level of HA by more than 30%, and N-PC type III by 90 %, compared with control indicators,a year or more after undergoing surgery for APD, LAIO, may indicate a high risk of recurrence and be used as anadditional prognostic indicator.3. Intraoperative use of sodium hyaluronate and decamethoxine in abdominal surgery and the use of localadhesiolysis as anti-adhesive measures help reduce the risk of re-adhesion in children.

Extracellular Vesicles Derived from Adipose Mesenchymal Stem Cells Promote Peritoneal Healing by Activating MAPK-ERK1/2 and PI3K-Akt to Alleviate Postoperative Abdominal Adhesion.

Peritoneal regeneration and repair can alleviate postoperative intraperitoneal adhesions, and mesenchymal stem cells (MSCs) have demonstrated the potential for peritoneal repair and regeneration. However, extracellular vesicles (EVs) are the main carriers for the MSC activity. Thus far, the roles of MSC-derived EVs on peritoneal repair are not well understood. To investigate the therapeutic effect of adipose-derived mesenchymal stem cell-derived EVs (ADSC-EVs) in peritoneal injuries, ADSC-EVs were injected in vivo via the tail vein of rats. The antiadhesion effects were evaluated following abdominal surgery. In addition, the levels of the peritoneal fibrinolysis system were determined via enzyme-linked immunosorbent assay. Expression differences in inflammatory and apoptotic markers were detected using immunofluorescence. The expression of extracellular matrix-related indexes and peritoneal healing were observed using immunohistochemistry. In vitro, rat peritoneal mesothelial cell proliferation was assessed via a 5-ethynyl-2-deoxyuridine assay. Cell migration was determined using scratch wound and transwell assays. Related signaling networks were estimated based on sequencing and bioinformatics analyses. The roles of the MAPK–ERK1/2 and PI3K–Akt signaling networks were analyzed using immunoblotting. This is the first report of the effectiveness of ADSC-EVs in the treatment of postoperative adhesions. ADSC-EVs were incorporated in vitro and induced rat peritoneal mesothelial cell proliferation and migration. This was mediated by stimulation of the MAPK–ERK1/2 and PI3K–Akt axes. ADSC-EVs promote the healing of the injured peritoneum, suggesting a promising therapeutic approach for peritoneal adhesions.

In Vivo Evaluation of a Pectin-Honey Hydrogel Coating on Polypropylene Mesh in a Rat Model of Acute Hernia

Investigations about ventral hernia repair are focused on improving the quality, resistance, and biocompatibility of mesh. This study compared plain polypropylene mesh with a pectin-honey hydrogel-coated polypropylene mesh in an acute hernia model in rats. Forty Wistar rats, randomly assigned to two groups, were submitted to laparotomy, and a 1 cm × 2 cm fascial defect was created, centered on the midline. Uncoated (group C) or coated mesh (group T) was inserted in an inlay fashion to repair the defect. After 30 days, the rats were euthanized, and the presence of adhesions to the mesh was macroscopically evaluated. Histology and measurement of COX-2 as tissue inflammation markers were used to assess fascia tissue healing. Grades of adhesion were not different between groups. Histological score and COX-2 expression were not significantly different between groups, except for the higher inflammatory response demonstrated in group T. The pectin-hydrogel coated mesh could not reduce adhesion formation compared to uncoated polypropylene mesh but improved peritoneal regeneration and tissue healing.

Regenerated silk fibroin (RSF) electrostatic spun fibre composite with polypropylene mesh for reconstruction of abdominal wall defects in a rat model

Abdominal wall defects are associated with abdominal wall surgery, infection and tumour resection. Polypropylene (PP) mesh, which has excellent mechanical strength, is currently the primary clinical repair material. In repairing the abdominal wall, the mesh can erode the bowel and cause other problems. Constructing a barrier that induces a weak inflammatory response and promotes rapid recovery of the peritoneum is important. We used electrospinning technology to construct a silk fibroin coating on the abdominal surface of a PP patch. A rat model was used to compare the inflammatory responses, regeneration of peritoneal tissue, and antiadhesion effects of electrospun regenerated silk fibroin (RSF) coatings, polycaprolactone (PCL) coatings, and noncoated PP meshes. The inflammatory responses, antiadhesion fractions, and areas of RSF and PCL were better than those of PP at 6 weeks. RSF was associated with complete peritoneal regeneration, in contrast to PCL. At 12 weeks, the structure of the PCL peritoneum was unstable, and the adhesion fraction and area were significantly higher than those of RSF. The intact peritoneum could not be effectively regenerated. The RSF group exhibited lower IL-6 levels than the PCL and PP groups but higher VEGF, IL-10 and TGF-β levels, making RSF more conducive to the regeneration of peritoneal and abdominal wall tissues.

Peritoneal regeneration and pathogenesis of postoperative peritoneal adhesions formation

Despite the long history of the peritoneal regeneration and the peritoneal adhesions formation pathogenesis studies, as well as a large number of clinical and experimental trials, so far, many questions about the pathophysiology of postoperative adhesions remain controversial. Postoperative formation of peritoneal adhesions is considered to be part of a pathological regeneration process that occurs after any peritoneum injury, especially in connection with surgery. Factors that lead to formation of adhesions are different (mechanical, physical, chemical, infectious, implantation). Inflammatory mediators, free radical oxidation processes, and oxidative stress also play an important role in the modulation of adhesions. A key role in the formation of adhesions belongs to pathological decrease in peritoneal fibrinolytic activity in response to inflammation and surgery. Studies on both animal models and humans have shown that two major factors lead to a decrease in fibrinolysis: a decrease in local tPA activity and an increase in PAI‑1 activity locally and systemically. It is the balance between the activity of tPA and PAI‑1 that plays a central role in the pathological adhesion formation, and the imbalance correlates with the severity of the adhesive process. Thus, pathological adhesion is a multifactorial condition, the development of which is due to a combination of various factors, many of which are genetically determined by local and systemic reactions of the body, and features of surgical treatment. To develop effective methods for prevention and treatment of adhesions, a more complete understanding of this process is needed at both the cellular and molecular genetic levels. The key to preventing post‑operative adhesion formation is likely to be the selective suppression of one or more critical factors that are necessary for its formation. There are practically no works in literature to study the features of adhesions pathogenesis in children.

The influences of a novel anti-adhesion device, thermally cross-linked gelatin film on peritoneal dissemination of tumor cells: The in vitro and in vivo experiments using murine carcinomatous peritonitis models.

To create anti-adhesive materials to be more effective and safer, we developed a thermally cross-linked gelatin film that showed superior anti-adhesive effects with excellent peritoneal regeneration. However, it may act as a convenient scaffold for tumor cell growth, thereby accelerating peritoneal dissemination when used in surgery for abdominal tumors. In this study, we tried to clarify this issue using mouse carcinomatous peritonitis models. First, we examined the in vitro tumor cell growth of mouse B16 melanoma or Colon26 cells on the gelatin film or the conventional hyarulonate/carboxymethylcellulose film. Tumor cell growth on each film was significantly lower than that of the control (no film). Next, we conducted the following in vivo experiments: After the parietal peritoneum was partially removed and covered with each film or without any film, mice were inoculated intraperitoneally with B16 melanoma or Colon26/Nluc cells expressing NanoLuc luciferase gene. At 7 days after the operation, we measured the weight of B16 melanoma tumors or the NanoLuc activity of Colon26/Nluc cells using in vivo imaging at the injured sites. There were no significant differences in the weight of the tumors and the NanoLuc activity among the three groups. We also observed the survival time of mice receiving the same operation and treatments. There was no significant difference in the survival time among the three groups. These results suggest that the gelatin film will likely not accelerate peritoneal dissemination as a convenient scaffold for tumor cell growth when used in surgery for abdominal tumors. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2122-2130, 2018.

The influences of thermally cross-linked gelatin film for intraperitoneal dissemination of tumor cells

Event Abstract Back to Event The influences of thermally cross-linked gelatin film for intraperitoneal dissemination of tumor cells Hiroe Miyamoto1, Hiroyuki Tsujimoto1, Koki Yamanaka1, Han Pei1, Tsunehito Horii1, Hiroko Torii1, Yuki Ozamoto1 and Akeo Hagiwara1 1 Doshisha University, Department of Medical Life System, Japan Introduction: To prevent adhesion formation after abdominal surgery, we have developed a thermally cross-linked gelatin film and previously reported its superior anti-adhesive effects with excellent peritoneal regeneration[1]. However, it may act as a scaffold convenient for tumor cell growth, thereby accelerating peritoneal dissemination when used in surgery for abdominal tumors since the gelatin film is made from a degenerated product of collagen which is the most abundant extracellular matrix protein in mammals and has been used as a scaffold in the field of regeneration medicine. In this study, we tried to clarify this issue in in vitro and in vivo experiments using mouse B16 melanoma cells and its carcinomatous peritonitis model, compared with HA/CMC film which is an anti-adhesive material composed of polysaccharides and has been used clinically. Materials, Methods and Results: At first, we examined the influence of the gelatin film for in vitro tumor cell growth. B16 melanoma cells were cultured on the gelatin film, HA/CMC film or without any film. Each viable cell number was counted with time. As the result, B16 melanoma cells grew on the gelatin film and HA/CMC film significantly lower than those in the control group. Next, we examined the influence of the gelatin film for peritoneal dissemination using B16 melanoma carcinomatous peritonitis model. After laparotomy, small parts of bilateral parietal peritoneum were removed mechanically. The injured site were covered with the gelatin film, HA/CMC film or without any films (control). Then, each mouse was inoculated intraperitoneally with the B16 melanoma cells, which has intrinsic black melanin pigmentation. At 7 days after the inoculation, the tumor weight of B16 melanoma at the injured sites were measured. The result showed no significant differences of the tumor weight among three groups. Furthermore, there was also no significant differences of the mean survival time of the mice among three groups with the gelatin film, HA/CMC film or without any films. Discussion: In the in vitro experiment, the gelatin film as well as the HA/CMC inhibited the growth of B16 melanoma cells unexpectedly, compared with the control group. In the in vivo experiments using B16 melanoma carcinomatous peritonitis model, both films did not influence the tumor growth or the survival times of the mice inoculated with the tumors. These results suggests that the both types of films do not enhance the tumor growth at the injured sites at least. Conclusions: Thermally cross-linked gelatin film does not act as a scaffold convenient for tumor cell growth, thereby accelerating peritoneal dissemination, when used in surgery for abdominal tumors.

Cell sheet-based tissue engineering for mesothelial cell injury.

Mesothelial cells are an integral part of the peritoneum and play an important role in maintaining its structure and functions. A number of studies have been performed to evaluate the ability of mesothelial cells to regenerate and transdifferentiate. Mesothelial cells are also involved in repairing the damage to the peritoneum as a result of surgery or peritonitis. Previous cell sheet engineering research has made it possible to transplant cells that retain their function, and stacking different types of cells in cell sheet layers has also become possible. Mesothelial cell transplantation as a means of achieving peritoneal regeneration needs to be performed under conditions in which the surface area of the visceral peritoneum is large and the area of mesothelial cell damage is small. In this chapter, we explain cell sheet engineering as a technology for transplanting cells in which a variety of intercellular adhesion and cell membrane molecules remain intact and the application of this technology to peritoneal regeneration.

Therapeutic applications of mesothelial cell sheets.

Mesothelial cells are an integral part of the peritoneum and play an important role in maintaining its structural and functional properties. In recent years a number of studies on mesothelial cells have been performed to evaluate the localization, secretional properties and the ability of regeneration and transdifferentiation of these cells. They are also involved in the repair of the peritoneum damage following surgery or peritonitis. Mesothelial cells produce several cytokines, growth factors and extracellular matrix components, possessing anti-inflammatory and immunomodulatory properties. Based on previous research, cell sheet engineering has made it possible to transplant cells that retain the cells' function, and stacking different cells in layers has also become possible. Arranging blood vessels between the cell layers is a problem when stacking cells in layers. Whether adequate blood flow can be obtained for the cell layers to survive long-term is the difference between success and failure. Mesothelial cell transplantation for peritoneal regeneration needs to be performed under conditions in which the surface area of the visceral peritoneum is large and the mesothelial cell damage area is small. In this article we explain cell sheet engineering as one of the technologies for transplanting cells with a variety of intercellular adhesion and cell membrane molecules maintained intact, and its application to peritoneal regeneration.

The Selection of Peritoneal Mesothelial Cells Is Important for Cell Therapy to Prevent Peritoneal Fibrosis

Long-term peritoneal dialysis (PD) causes chronic peritoneal damage. Peritoneal mesothelial cells (PMCs) play an important role in peritoneal function. We investigated the possibility of cell therapy using the PMCs to prevent peritoneal damage in PD patients. We harvested human PMCs from the PD effluent of PD patients. The PMCs were separated based on morphological characteristics into epithelial-like (Epi) cells and fibroblast-like (Fib) cells by the limiting dilution method. We transplanted these cells into nude mice whose parietal and visceral peritoneum were scratched by mechanical scraping. The transplanted cells were detected at the parietal and visceral peritoneum. Compared with the positive control, the Epi cell therapy group showed very few adhesions and exhibited no thickening of the parietal and visceral peritoneum. However, the group with Fib cell therapy could not inhibit peritoneal adhesion and thickening. In addition, hepatocyte growth factor was expressed by the grafted Epi cells but not Fib cells. Fib cells expressed vascular endothelial growth factor stronger than Epi cells. These two types of cells from the same patient showed different characteristics and effects for cell therapy. These findings suggest that the PMCs from the PD patient showed different characteristics, such as Epi cells and Fib cells, and the selection of PMCs is important for cell therapy on the point of not only the direct cellular interactions but also cytokine secretion from the grafted cells. Furthermore, the differences in the morphological cell characteristics may influence their role in peritoneal regeneration.

Behaviour of a New Composite Mesh for the Repair of Full-Thickness Abdominal Wall Defects in a Rabbit Model

IntroductionComposite biomaterials designed for the repair of abdominal wall defects are composed of a mesh component and a laminar barrier in contact with the visceral peritoneum. This study assesses the behaviour of a new composite mesh by comparing it with two latest-generation composites currently used in clinical practice.MethodsDefects (7x5cm) created in the anterior abdominal wall of New Zealand White rabbits were repaired using a polypropylene mesh and the composites: PhysiomeshTM; VentralightTM and a new composite mesh with a three-dimensional macroporous polyester structure and an oxidized collagen/chitosan barrier. Animals were sacrificed on days 14 and 90 postimplant. Specimens were processed to determine host tissue incorporation, gene/protein expression of neo-collagens (RT-PCR/immunofluorescence), macrophage response (RAM-11-immunolabelling) and biomechanical resistance. On postoperative days 7/14, each animal was examined laparoscopically to quantify adhesions between the visceral peritoneum and implant.ResultsThe new composite mesh showed the lowest incidence of seroma in the short term. At each time point, the mesh surface covered with adhesions was greater in controls than composites. By day 14, the implants were fully infiltrated by a loose connective tissue that became denser over time. At 90 days, the peritoneal mesh surface was lined with a stable mesothelium. The new composite mesh induced more rapid tissue maturation than PhysiomeshTM, giving rise to a neoformed tissue containing more type I collagen. In VentralightTM the macrophage reaction was intense and significantly greater than the other composites at both follow-up times. Tensile strengths were similar for each biomaterial.ConclusionsAll composites showed optimal peritoneal behaviour, inducing good peritoneal regeneration and scarce postoperative adhesion formation. A greater foreign body reaction was observed for VentralightTM. All composites induced good collagen deposition accompanied by optimal tensile strength. The three-dimensional macroporous structure of the new composite mesh may promote rapid tissue regeneration within the mesh.

Pilot study evaluating the efficacy of AlloMEM™ for prevention of intraperitoneal adhesions and peritoneal regeneration after loop ileostomy

This study was designed to evaluate the feasibility of AlloMEM™, a novel lyophililzed human peritoneal membrane, at peritoneal reconstitution, and decreasing adhesion formation after temporary loop ileostomy. In a pilot study, ten patients had AlloMEM™ used during elective formation of a temporary diverting loop ileostomy for benign or malignant colorectal disease. A blinded investigator and the operating surgeon analyzed the change in adhesion formation and peritoneal remodelling using ileostomy mobilization time and a 5-point adhesion scale grading intra-abdominally and at the subcutaneous and fascial levels. The mean body mass index was 31 [standard deviation (SD) 5.6], and 40 % of patients had previous abdominal surgery. Ileostomies were reversed after a mean 14 weeks (SD 6.0). The mean ileostomy mobilization time was 27.2 min (SD 12.0). From baseline to ileostomy reversal, there were significant increases in adhesions at the subcutaneous (p = 0.0002) and fascial levels (p = 0.0024). The increased subcutaneous adhesions were associated with improved peritoneal remodeling. There was no significant increase in adhesions from baseline to ileostomy reversal at the intra-abdominal points (p = 0.9393) or around the ileostomy site (p = 0.6128). The median hospital length of stay was 2.6 days (range, 2-3). A single adverse event related to product packaging led to redesign of the packaging process. Use of AlloMEM™ in ileostomy closures suggested improvement in adhesions around the fascia and promotion of peritoneal remodeling. AlloMEM™ was safe, feasible, and easy to use in this pilot study. Comparative research is needed to assess the outcomes with this novel product.

Peritoneal repairing cells: a type of bone marrow derived progenitor cells involved in mesothelial regeneration

The peritoneal mesothelium exhibits a high regenerative ability. Peritoneal regeneration is concomitant with the appearance, in the coelomic cavity, of a free-floating population of cells whose origin and functions are still under discussion. We have isolated and characterized this cell population and we have studied the process of mesothelial regeneration through flow cytometry and confocal microscopy in a murine model lethally irradiated and reconstituted with GFP-expressing bone marrow cells. In unoperated control mice, most free cells positive for mesothelin, a mesothelial marker, are green fluorescent protein (GFP). However, 24 hrs after peritoneal damage, free mesothelin+/ GFP+ cells appear in peritoneal lavages. Cultured lavage peritoneal cells show colocalization of GFP with mesothelial (mesothelin, cytokeratin) and fibroblastic markers. Immunohistochemical staining of the peritoneal wall also revealed colocalization of GFP with mesothelial markers and with procollagen-1 and smooth muscle α-actin. This was observed in the injured area as well as in the surrounding not-injured peritoneal surfaces. These cells, which we herein call peritoneal repairing cells (PRC), are very abundant 1 week after surgery covering both the damaged peritoneal wall and the surrounding uninjured area. However, they become very scarce 1 month later, when the mesothelium has completely healed. We suggest that PRC constitute a type of monocyte-derived cells, closely related with the tissue-repairing cells known as ‘fibrocytes’ and specifically involved in peritoneal reparation. Thus, our results constitute a synthesis of the different scenarios hitherto proposed about peritoneal regeneration, particularly recruitment of circulating progenitor cells and adhesion of free-floating coelomic cells.

An integrin-activating peptide, PHSRN, ameliorates inhibitory effects of conventional peritoneal dialysis fluids on peritoneal wound healing

Bioincompatible peritoneal dialysis fluids (PDFs) cause pathological changes in the peritoneal membrane, related to membrane dysfunction and progressive peritoneal fibrosis. We investigated the effects of Pro-His-Ser-Arg-Asn (PHSRN) peptide, one of the fibronectin cell-binding domains that activates integrins and reinforces wound healing, on peritoneal remodelling in a rat peritoneal injury model undergoing peritoneal dialysis. The peritoneal mesothelial monolayer was removed by a stripping procedure in rats receiving conventional high glucose-containing PDF supplemented with or without PHSRN or control His-Ser-Pro-Asn-Hrg (HSPNR) peptides. Effects of PHSRN on cell motility and signalling molecules were examined in cultured rat peritoneal mesothelial cells (RPMCs) and normal rat kidney fibroblasts (NRKs). The cytokeratin- and HBME-1-positive mesothelial cell monolayer was selectively removed by the procedure. By day 6, HBME-1-positive cells had regenerated to 53.3 +/- 6.5% of the peritoneal surface in the control group. Regeneration of the mesothelial layer was delayed in the PDF group (35.2 +/- 10.2%, P < 0.05), but PHSRN reversed the effects of PDF (51.7 +/- 9.6%, P < 0.05). PDF treatment increased thickening of granulomatous submesothelial tissue and numbers of ED1-, CD31- and alpha-smooth muscle actin-positive cells, but PHSRN ameliorated these effects. HSPNR had no effects on mesothelial regeneration or peritoneal wound healing. PHSRN, but not HSPNR, recovered glucose-induced inhibition of cell motility and phosphorylation of focal adhesion kinase and its downstream p130(Cas) in RPMCs and NRKs. These results suggest that PHSRN has beneficial effects on peritoneal regeneration by reducing the inhibitory effects of conventional PDF on integrin-mediated wound healing.

Postoperative intraperitoneal adhesion pathophysiology

Aside from the normal 'ad integrum' peritoneal regeneration, the postoperative intraperitoneal adhesion formation process may be considered as the pathological part of peritoneal healing following any injury, particularly a surgical one. Despite a large body of clinical and experimental studies, its pathophysiology remains controversial. Moreover, a better understanding of the pathophysiological events and of the medical and surgical factors involved in the adhesion formation process is pivotal in any attempt to control this very frequent phenomenon and its serious consequences.

Peritoneal Regeneration Induced by an Acellular Bovine Pericardial Patch in the Repair of Abdominal Wall Defects

Peritoneal Regeneration Induced by an Acellular Bovine Pericardial Patch in the Repair of Abdominal Wall Defects

Peritoneal Regeneration Induced by an Acellular Bovine Pericardial Patch in the Repair of Abdominal Wall Defects

This study was to evaluate the feasibility of using an acellular bovine pericardium fixed with genipin (AGP) to repair an abdominal wall defect created in a rat model. The glutaraldehyde-fixed acellular pericardium (AGA), the genipin-fixed cellular pericardium (GP), and a commercially available polypropylene mesh were used as controls. Gross examination at 3-month post-operatively revealed that dense adhesions to the visceral organs were observed for the polypropylene mesh and the AGA patch, while a filmy to dense adhesion was seen for the GP patch. In contrast, no adhesion to the visceral organs was observed for the AGP patch. Histologically, inflammatory cells were found mainly surrounding the GP patch. In contrast, host cells (inflammatory cells, fibroblasts, and neo-capillaries) were able to infiltrate into the AGA and AGP patches. Unlike the AGA patch, the AGP patch retrieved at 1-month post-operatively became well integrated with the host tissue near the suture line. Additionally, there were some mesothelial cells, identified by the van Gieson stain, observed on the AGP patch. At 3-month post-operatively, a neo-peritoneum was observed on the AGP patch. The neo-peritoneum consisted of organized vascularized connective tissues covered by an intact layer of mesothelial cells. The calcium contents of the polypropylene mesh and the AGA patch increased significantly at 3-month post-operatively, while those of the GP and AGP patches stayed minimal throughout the entire course of the study. The results obtained in the study revealed that the AGP patch effectively repaired abdominal wall defects in rats and successfully prevented the formation of post-surgical abdominal adhesions.

Infertility due to diseased pelvic peritoneum: laparoscopic treatment.

Thirty-one patients complaining of unexplained infertility for at least 36 months and diagnosed elsewhere were reassessed laparoscopically. After staining their pelvic peritoneum with concentrated methylene blue, they presented with extensive areas of dark blue discoloration, and were diagnosed as suffering from 'diseased pelvic peritoneum'. The levels of peritoneal CA 125 were assessed. At the end of the diagnostic procedure, bipolar electrocoagulation or defocalized laser beam therapy was performed to destroy the affected peritoneal areas, and to allow peritoneal regeneration. Twenty-five pregnancies were obtained following this treatment. A detailed description is given of the diagnosis and treatment procedures.