Ascites-induced compression alters the peritoneal microenvironment and promotes metastatic success in ovarian cancer.

The majority of women with recurrent ovarian cancer (OvCa) develop malignant ascites with volumes that can reach > 2 L. The resulting elevation in intraperitoneal pressure (IPP), from normal values of 5 mmHg to as high as 22 mmHg, causes striking changes in the loading environment in the peritoneal cavity. The effect of ascites-induced changes in IPP on OvCa progression is largely unknown. Herein we model the functional consequences of ascites-induced compression on ovarian tumor cells and components of the peritoneal microenvironment using a panel of in vitro, ex vivo and in vivo assays. Results show that OvCa cell adhesion to the peritoneum was increased under compression. Moreover, compressive loads stimulated remodeling of peritoneal mesothelial cell surface ultrastructure via induction of tunneling nanotubes (TNT). TNT-mediated interaction between peritoneal mesothelial cells and OvCa cells was enhanced under compression and was accompanied by transport of mitochondria from mesothelial cells to OvCa cells. Additionally, peritoneal collagen fibers adopted a more linear anisotropic alignment under compression, a collagen signature commonly correlated with enhanced invasion in solid tumors. Collectively, these findings elucidate a new role for ascites-induced compression in promoting metastatic OvCa progression.

Fibrin Deposit on the Peritoneal Surface Serves as a Niche for Cancer Expansion in Carcinomatosis Patients.

Peritoneal metastasis (PM) is a very serious complication of gastrointestinal and gynecological malignancies which is poorly documented. Modified mesothelial cell layer and their microenvironments can favor fibrin deposition for cancer cell adhesion. Scanning and transmission electron microscopy of peritoneal surface and cancer cell clusters from cancer patients was done. Ascites and its impact on mesothelial cells were assessed by cytokine array. Neprilysin, matrix metalloprotease, epithelial mesenchymal transition (EMT) related molecules (E-cadherin, Snail, Slug, Twist, Vimentin and Fibronectin), tissues factor (TF), endothelial protein C receptors (EPCR) were quantified by q-PCR. Fibrin in the simples were stained using anti fibrin F1E1 antibody. Migration ability was assessed by scratch assay. Cell viability and neprilysin activity were analyzed by bioluminescence. Cancer cells-fibrin interaction was investigated by scanning electron microscopy (SEM) and microcinematography (MCG). Mesothelial cells change their morphology after incubation with carcinomatosis peritoneal fluids in vitro. EMT associated with upregulation of neprilysin, matrix metalloproteinase-2, tissue factor and cytokines secretions such as interleukin-6, and 8, hepatocyte growth factor and granulocyte chemotactic protein-2 mRNA and protein were observed. EPCR expression as a natural anticoagulant was decreased. In parallel, carcinomatosis cell clusters extracted from peritoneal fluids were found to be associated with fibrin. Kinetic analysis of cancer cell-fibrin interaction in vitro studied by MCG showed that fiber filaments generated from clots inhibited cancer cell adhesion on fibrin clots. These results indicated that fibrin deposit on the peritoneal surface serve as niches for cancer expansion in carcinomatosis patients.

Exosomes: The New Mediator of Peritoneal Membrane Function.

Fibrosis and angiogenesis are the most common processes that result in progressive peritoneal tissue remodeling and, eventually, peritoneal membrane dysfunction. The role of exosomes, which contributes to intercellular communication, in these processes has been neglected. Various biomolecules, including DNA, mRNA, proteins, lipids, and particular certain miRNAs, can be transferred by exosomes to local, neighboring and distal cells. Upon stimulation by cytokines or other microenvironment stimuli, donor cells release a mass of exosomes to peritoneal mesothelial cells, further affecting fibrosis and angiogenesis. This important exosomes-mediated intracellular communication is thought to regulate peritoneal membrane function. Understanding the molecular mechanisms of these processes, targeting changes in exosomes and regulating exosomal miRNAs will advance therapeutic methods for protecting peritoneal membrane function.

Assessment of Peritoneal Membrane Arteriolar Structure in Conjunction with Traditional Cardiovascular System Evaluation in Chronic Kidney Disease (CKD) Stage 5 Patients.

BACKGROUND/AIMS: Cardiovascular complications are responsible for increased mortality and morbidity in chronic kidney disease (CKD) patients. Functional and structural changes of peritoneal membrane are reported in CKD patients both on conservative treatment and on renal replacement therapy (RRT). The aim of the study was to assess the structure of peritoneal membrane small arteries (precapillary arterioles) in diabetic and non-diabetic CKD stage 5 patients before initiation of peritoneal dialysis (PD) and evaluate its relationship with heart and large arteries abnormalities and with selected biochemical parameters. METHODS: Evaluation of 42 CKD stage 5 patients before starting PD. Diabetic (n=26) and non-diabetic (n=16) patients were compared. Peritoneal membrane samples were taken during Tenckhoff catheter insertion. Histopathological evaluation of peritoneal precapillary arterioles (arteriolar evaluation) with measurement of wall thickness (WT) and calculation of lumen/vessel (L/V) ratio was performed in each patients. Echocardiography, intima media thickness (IMT), pulse wave velocity (PWV), ambulatory blood pressure monitoring (ABPM) and biochemical parameters assessment: serum albumin (SA), total cholesterol (TCH), hemoglobin (Hgb), parathormone (PTH), serum calcium (Ca), serum phosphorus (P), transferrin saturation (TSAT%), C-reactive protein (CRP) were performed in each participant. RESULTS: There were no statistically significant differences in peritoneal membrane arteriolar indices - wall thickness (WT) and L/V ratio between investigated groups. There was statistically significant higher PWV value in diabetic patients. There were no statistically significant differences in echocardiographic indices, IMT, laboratory data in analyzed groups. There were some linear correlations between: PWV vs IMT (R=0,84; p=0,0006); PWV vs PP (R=0,58; p=0,03) in non-diabetic and linear correlation between: PWV vs age (R=0,75; p=0,02); WT vs DP (R=-0,93; p=0,001); WT vs DBP ( R=0,64; p=0,04) in diabetic group. CONCLUSION: Peritoneal membrane arteriolar damage seems to be an integrated part of cardiovascular system damage in CKD stage 5 patients.

The mechanical microenvironment regulates ovarian cancer cell morphology, migration, and spheroid disaggregation.

There is growing appreciation of the importance of the mechanical properties of the tumor microenvironment on disease progression. However, the role of extracellular matrix (ECM) stiffness and cellular mechanotransduction in epithelial ovarian cancer (EOC) is largely unknown. Here, we investigated the effect of substrate rigidity on various aspects of SKOV3 human EOC cell morphology and migration. Young's modulus values of normal mouse peritoneum, a principal target tissue for EOC metastasis, were determined by atomic force microscopy (AFM) and hydrogels were fabricated to mimic these values. We find that cell spreading, focal adhesion formation, myosin light chain phosphorylation, and cellular traction forces all increase on stiffer matrices. Substrate rigidity also positively regulates random cell migration and, importantly, directional increases in matrix tension promote SKOV3 cell durotaxis. Matrix rigidity also promotes nuclear translocation of YAP1, an oncogenic transcription factor associated with aggressive metastatic EOC. Furthermore, disaggregation of multicellular EOC spheroids, a behavior associated with dissemination and metastasis, is enhanced by matrix stiffness through a mechanotransduction pathway involving ROCK, actomyosin contractility, and FAK. Finally, this pattern of mechanosensitivity is maintained in highly metastatic SKOV3ip.1 cells. These results establish that the mechanical properties of the tumor microenvironment may play a role in EOC metastasis.

Autophagy promotes fibrosis and apoptosis in the peritoneum during long-term peritoneal dialysis.

Long-term peritoneal dialysis is accompanied by functional and histopathological alterations in the peritoneal membrane. In the long process of peritoneal dialysis, high-glucose peritoneal dialysis solution (HGPDS) will aggravate the peritoneal fibrosis, leading to decreased effectiveness of peritoneal dialysis and ultrafiltration failure. In this study, we found that the coincidence of elevated TGF-ß1 expression, autophagy, apoptosis and fibrosis in peritoneal membrane from patients with peritoneal dialysis. The peritoneal membranes from patients were performed with immunocytochemistry and transmission electron microscopy. Human peritoneal mesothelial cells were treated with 1.5%, 2.5% and 4.25% HGPDS for 24 hrs; Human peritoneal mesothelial cells pre-treated with TGF-ß1 (10 ng/ml) or transfected with siRNA Beclin1 were treated with 4.25% HGPDS or vehicle for 24 hrs. We further detected the production of TGF-ß1, activation of TGF-ß1/Smad2/3 signalling, induction of autophagy, EMT, fibrosis and apoptosis. We also explored whether autophagy inhibition by siRNA targeting Beclin 1 reduces EMT, fibrosis and apoptosis in human peritoneal mesothelial cells. HGPDS increased TGF-ß1 production, activated TGF-ß1/Smad2/3 signalling and induced autophagy, fibrosis and apoptosis hallmarks in human peritoneal mesothelial cells; HGPDS-induced Beclin 1-dependent autophagy in human peritoneal mesothelial cells; Autophagy inhibition by siRNA Beclin 1 reduced EMT, fibrosis and apoptosis in human peritoneal mesothelial cells. Taken all together, these studies are expected to open a new avenue in the understanding of peritoneal fibrosis, which may guide us to explore the compounds targeting autophagy and achieve the therapeutic improvement of PD.

The Peritoneum: Health, Disease, and Perspectives regarding Tissue Engineering and Cell Therapies.

There are several pathologies associated with the peritoneum, such as mesothelioma and peritonitis. Moreover, the peritoneum is widely used in ultrafiltration procedures, i.e., peritoneal dialysis, presenting advantages over hemodialysis. On the other hand, ultrafiltration failure may lead to dialysis-induced fibrosis and hypervolemia. Therefore, the pathophysiological study of this tissue is of extreme biomedical importance. Studies investigating the biology of the cells dwelling in the peritoneum wall provide evidence of their plasticity and progenitor features. For instance, both mesothelial and submesothelial cells present characteristics similar to mesenchymal stem cells, including osteogenic and adipogenic differentiation potential, support of extramedullary hematopoiesis, modulation of inflammatory responses, and regulation of tumor progression. Indeed, the participation of each cell type in peritoneal pathological and physiological phenomena is still under debate, especially regarding a possible differentiation pathway connecting these peritoneal cells. The primary aim of this review is to raise this discussion. In order to do so, we will firstly provide an overview of the peritoneum anatomy, histology, and ontology, and finally we will address how a better understanding of peritoneal cell biology may contribute to future cell therapy and tissue engineering approaches.

Post-translational modification of the membrane type 1 matrix metalloproteinase (MT1-MMP) cytoplasmic tail impacts ovarian cancer multicellular aggregate dynamics.

Membrane type 1 matrix metalloproteinase (MT1-MMP, MMP-14) is a transmembrane collagenase highly expressed in metastatic ovarian cancer and correlates with poor survival. Accumulating evidence shows that the cytoplasmic tail of MT1-MMP is subjected to phosphorylation, and this post-translational modification regulates enzymatic activity at the cell surface. To investigate the potential role of MT1-MMP cytoplasmic residue Thr567 phosphorylation in regulation of metastasis-associated behaviors, ovarian cancer cells that express low endogenous levels of MT1-MMP were engineered to express wild-type MT1-MMP, a phosphomimetic mutant (T567E), or a phosphodeficient mutant (T567A). Results show that Thr567 modulation influences behavior of both individual cells and multicellular aggregates (MCAs). The acquisition of either wild-type or mutant MT1-MMP expression results in altered cohesion of epithelial sheets and the formation of more compact MCAs relative to parental cells. Cells expressing MT1-MMP-T567E phosphomimetic mutants exhibit enhanced cell migration. Furthermore, MCAs formed from MT1-MMP-T567E-expressing cells adhere avidly to both intact ex vivo peritoneal explants and three-dimensional collagen gels. Interaction of these MCAs with peritoneal mesothelium disrupts mesothelial integrity, exposing the submesothelial collagen matrix on which MT1-MMP-T567E MCAs rapidly disperse. Together, these findings suggest that post-translational regulation of the Thr567 in the MT1-MMP cytoplasmic tail may function as a regulatory mechanism to impact ovarian cancer metastatic success.

Vascularization Potential of Electrospun Poly(L-Lactide-co-Caprolactone) Scaffold: The Impact for Tissue Engineering.

BACKGROUND Electrospun nanofibers have widespread putative applications in the field of regenerative medicine and tissue engineering. When compared to naturally occurring collagen matrices, electrospun nanofiber scaffolds have two distinct advantages: they do not induce a foreign body reaction and they are not at risk for biological contamination. However, the exact substrate, structure, and production methods have yet to be defined. MATERIAL AND METHODS In the current study, tubular-shaped poly(L-lactide-co-caprolactone) (PLCL) constructs produced using electrospinning technology were evaluated for their potential application in the field of tissue regeneration in two separate anatomic locations: the skin and the abdomen. The constructs were designed to have an internal diameter of 3 mm and thickness of 200 µm. Using a rodent model, 20 PLCL tubular constructs were surgically implanted in the abdominal cavity and subcutaneously. The constructs were then evaluated histologically using electron microscopy at 6 weeks post-implantation. RESULTS Histological evaluation and analysis using scanning electron microscopy showed that pure scaffolds by themselves were able to induce angiogenesis after implantation in the rat model. Vascularization was observed in both tested groups; however, better results were obtained after intraperitoneal implantation. Formation of more and larger vessels that migrated inside the scaffold was observed after implantation into the peritoneum. In this group no evidence of inflammation and better integration of scaffold with host tissue were noticed. Subcutaneous implantation resulted in more fibrotic reaction, and differences in cell morphology were also observed between the two tested groups. CONCLUSIONS This study provides a standardized evaluation of a PLCL conduit structure in two different anatomic locations, demonstrating the excellent ability of the structure to achieve vascularization. Functional, histological, and mechanical data clearly indicate prospective clinical utilization of PLCL in critical size defect regeneration.

Silk fibroin hydrogel as physical barrier for prevention of post hernia adhesion.

BACKGROUND: Adhesion formation remains a major complication following hernia repair surgery. Physical barriers though effective for adhesion prevention in clinical settings are associated with major disadvantages, therefore, needs further investigation. This study evaluates silk fibroin hydrogel as a physical barrier on polypropylene mesh for the prevention of adhesion following ventral hernia repair. STUDY DESIGN: Peritoneal explants were cultured on silk fibroin scaffold to evaluate its support for mesothelial cell growth. Full thickness uniform sized defects were created on the ventral abdominal wall of rabbits, and the defects were covered either with silk hydrogel coated polypropylene mesh or with plain polypropylene mesh as a control. The animals were killed after 1 month, and the adhesion formation was graded; healing response of peritoneum was evaluated by immunohistochemistry with calretinin, collagen staining of peritoneal sections, and expression of PCNA, collagen-I, TNFα, IL6 by real time PCR; and its adverse effect if any was determined. RESULTS: Silk fibroin scaffold showed excellent support for peritoneal cell growth in vitro and the cells expressed calretinin. A remarkable prevention of adhesion formation was observed in the animals implanted with silk hydrogel coated mesh compared to the control group; in these animals peritoneal healing was complete and predominantly by mesothelial cells with minimum fibrotic changes. Expression of inflammatory cytokines decreased compared to control animals, histology of abdominal organs, haematological and blood biochemical parameters remained normal. CONCLUSION: Therefore, silk hydrogel coating of polypropylene mesh can improve peritoneal healing, minimize adhesion formation, is safe and can augment the outcome of hernia surgery.

Application of imaging flow cytometry for characterization of acute inflammation in non-classical animal model systems.

Phagocytes display marked heterogeneity in their capacity to induce and control acute inflammation. This has a significant impact on the effectiveness of antimicrobial immune responses at different tissue sites as well as their predisposition for inflammation-associated pathology. Imaging flow cytometry provides novel opportunities for characterization of these phagocyte populations through high spatial resolution, statistical robustness, and a broad range of quantitative morphometric cell analysis tools. This study highlights an integrative approach that brings together new tools in imaging flow cytometry with conventional methodologies for characterization of phagocyte responses during acute inflammation. We focus on a comparative avian in vivo challenge model to showcase the added depth gained through these novel quantitative multiparametric approaches even in the absence of antibody-based cellular markers. Our characterization of acute inflammation in this model shows significant conservation of phagocytic capacity among avian phagocytes compared to other animal models. However, it also highlights evolutionary divergence with regards to phagocyte inflammation control mechanisms based on the internalization of apoptotic cells.

Ultrastructural Investigation of Pelvic Peritoneum in Patients With Chronic Pelvic Pain and Subtle Endometriosis in Association With Chromoendoscopy.

STUDY OBJECTIVE: To evaluate the pelvic peritoneum under chromoendoscopy by scanning electron microscopy (SEM) as well as light microscopy with hematoxylin and eosin staining and immunohistochemistry (IHC) assays in patients with chronic pelvic pain (CPP) associated with subtle endometriosis. DESIGN: Case series study (Canadian Task Force classification II). SETTING: A referral academic community tertiary medical center. PATIENTS: Three women aged 29 to 37 years were referred to the obstetrics and gynecology clinic of the tertiary university hospital with CPP. They were suspicious for endometriosis, were not responding to medical treatments, and had undergone previous pelvic laparoscopy to determine the stage of endometriosis and preparation of peritoneal samples under the guidance of staining with methylene blue in 0.25% dilution. INTERVENTIONS: Comparison of stained and unstained pelvic peritoneal samples after the instillation of 0.25% methylene blue into the pelvic cavity. MEASUREMENTS AND MAIN RESULTS: In 3 patients, laparoscopic examination showed minimal endometriosis. A total of 18 samples (9 stained and 9 unstained) from the 3 patients were prepared for SEM. Ten of the samples (55.6%) showed microstructural peritoneal destruction (7 of 9 stained [77.7%] and 3 of 9 [33.4%] unstained). Eighteen samples (9 stained and 9 unstained) from the 3 patients were also prepared for IHC. Six of these samples (33.3%) were S-100-positive, including 4 of 9 (44.4%) stained samples and 2 of 9 (22.2%) unstained samples. CONCLUSIONS: In general, in the context of CPP and endometriosis, there is no established relationship between the severity of pain and stage of endometriosis. In the pathophysiology of CPP associated with endometriosis, ultrastructural changes can play a significant role. Under methylene blue staining, some destroyed areas were detected, but the stained areas do not necessarily correlate with increased microstructural peritoneal destruction.

Peritoneal adhesion prevention with a biodegradable and injectable N,O-carboxymethyl chitosan-aldehyde hyaluronic acid hydrogel in a rat repeated-injury model.

Postoperative peritoneal adhesion is one of the serious issues because it induces severe clinical disorders. In this study, we prepared biodegradable and injectable hydrogel composed of N,O-carboxymethyl chitosan (NOCC) and aldehyde hyaluronic acid (AHA), and assessed its anti-adhesion effect in a rigorous and severe recurrent adhesion model which is closer to clinical conditions. The flexible hydrogel, which gelated in 66 seconds at 37 °C, was cross-linked by the schiff base derived from the amino groups of NOCC and aldehyde groups in AHA. In vitro cytotoxicity test showed the hydrogel was non-toxic. In vitro and in vivo degradation examinations demonstrated the biodegradable and biocompatibility properties of the hydrogel. The hydrogel discs could prevent the invasion of fibroblasts, whereas fibroblasts encapsulated in the porous 3-dimensional hydrogels could grow and proliferate well. Furthermore, the hydrogel was applied to evaluate the anti-adhesion efficacy in a more rigorous recurrent adhesion model. Compared with normal saline group and commercial hyaluronic acid (HA) hydrogel, the NOCC-AHA hydrogel exhibited significant reduction of peritoneal adhesion. Compared to control group, the blood and abdominal lavage level of tPA was increased in NOCC-AHA hydrogel group. These findings suggested that NOCC-AHA hydrogel had a great potential to serve as an anti-adhesion candidate.

Assessment of asbestos body formation by high resolution FEG-SEM after exposure of Sprague-Dawley rats to chrysotile, crocidolite, or erionite.

This work presents a comparative FEG-SEM study of the morphological and chemical characteristics of both asbestos bodies and fibres found in the tissues of Sprague-Dawley rats subjected to intraperitoneal or intrapleural injection of UICC chrysotile, UICC crocidolite and erionite from Jersey, Nevada (USA), with monitoring up to 3 years after exposure. Due to unequal dosing based on number of fibres per mass for chrysotile with respect to crocidolite and erionite, excessive fibre burden and fibre aggregation during injection that especially for chrysotile would likely not represent what humans would be exposed to, caution must be taken in extrapolating our results based on instillation in experimental animals to human inhalation. Notwithstanding, the results of this study may help to better understand the mechanism of formation of asbestos bodies. For chrysotile and crocidolite, asbestos bodies are systematically formed on long asbestos fibres. The number of coated fibres is only 3.3% in chrysotile inoculated tissues. In UICC crocidolite, Mg, Si, and Fe are associated with the fibres whereas Fe, P and Ca are associated with the coating. Even for crocidolite, most of the observed fibres are uncoated as coated fibres are about 5.7%. Asbestos bodies do not form on erionite fibres. The crystal habit, crystallinity and chemistry of all fibre species do not change with contact time, with the exception of chrysotile which shows signs of leaching of Mg. A model for the formation of asbestos bodies from mineral fibres is postulated. Because the three fibre species show limited signs of dissolution in the tissue, they cannot act as source of elements (primarily Fe, P and Ca) promoting nucleation and growth of asbestos bodies. Hence, the limited number of coated fibres should be due to the lack of nutrients or organic nature.

Utilización del Ultrasonido como Valoración Inicial de la Indemnidad de la Pared Abdominal en Traumatismos por Herida de Arm a Blanca en Abdomen / Using Ultrasound as the Initial Assessment of the Indemnity abdominal wall Injuries stab wound in abdomen

Introducción: Los traumatismos abdominales penetrantes son debidos generalmente a heridas de arma blanca o heridas de arma de fuego. Todas deben explorarse instrumentalmente bajo anestesia local con el objetivo de determinar la integridad del peritoneo. El ultrasonido es una herramienta muy útil utilizada en trauma, además del FAST, se lo puede utilizar en la urgencia como método de gran ayuda al realzar la exploración inicial de la herida para evaluar la integridad del peritoneo. Objetivos: Destacar la importancia del conocimiento anatómico y la correlación anatomo-clínico quirúrgica y ecográfica en la interpretación de imágenes obtenidas por ultrasonografía en la evaluación de la integridad de la pared del abdomen en heridas penetrantes por arma blanca. Material y métodos: FAST y ecografía de partes blandas instrumentándose la herida abdominal bajo anestesia local evaluando la indemnidad del peritoneo mediante la observación por ultrasonografía del abdomen y de la pared antero lateral del mismo en 14 de 42 pacientes con heridas por arma blanca en abdomen en el Servicio de Emergencias del Hospital Municipal de Morón y en el Servicio de Cirugía General del Hospital Aeronáutico Central. Período entre Febrero 2014 y Marzo 2015. Resultados: 42 (100%) pacientes con heridas de arma blanca en abdomen. 28 (66,66%) fueron inicialmente intervenidos quirúrgicamente. A 14 (33,34%) se le realizó FAST en búsqueda de líquido libre y ecografía de partes blandas instrumentándose la herida abdominal bajo anestesia local evaluando la indemnidad del peritoneo. Conclusiones: El conocimiento de las estructuras anatómicas y la disposición de las mismas que componen la pared anterolateral del abdomen permiten facilitar el reconocimiento de la indemnidad o no del peritoneo en las imágenes obtenidas por ultrasonido en pacientes con heridas abiertas por arma blanca, evitando así la realización de procedimientos quirúrgicos innecesarios.(AU)

Introduction: Penetrating abdominal trauma are usually due to stab wounds or gunshot wounds. All instrumentally be explored under local anesthesia in order to determine the integrity of the peritoneum. Ultrasound is a very useful tool used in trauma, in addition to FAST, I can use the urgency as a means of great help to enhance the initial exploration of the wound to evaluate the integrity of the peritoneum. Objectives: Highlighting the importance of the anatomical knowledge and surgical and anatomical clinical ultrasound in interpreting images obtained by ultrasonography in the evaluation of the integrity of the abdominal wall in penetrating stab wounds correlation. Material and methods: FAST ultrasound was performed and soft tissue abdominal wound became operational under local anesthesia indemnity evaluating the peritoneum through observation by ultrasound of the abdomen and the anterolateral wall thereof in 14 of the 42 patients with stab wounds in the abdomen Service Municipal Emergency Hospital of Moron and the Department of General Surgery of the Central Aeronautical Hospital, period between February 2014 and March 2015. Results: Of the 42 (100%) patients with stab wounds to the abdomen, 28 (66.66%) initially underwent surgery, and 14 (33.34%) were performed in FAST Search of free fluid and soft tissue ultrasound became operational abdominal wound under local anesthesia indemnity evaluating the peritoneum. Conclusions: Knowledge of the anatomical structures and arrangement thereof comprising the anterolateral wall of the abdomen allow easy recognition of indemnity or not the peritoneum in the ultrasound images in patients with stab wounds open, thus avoiding making unnecessary surgical procedures.

The effects of Panax notoginseng saponins on the cytokines and peritoneal function in rats with peritoneal fibrosis.

BACKGROUND: Due to the long-term and chronic exposure to the peritoneal dialysis fluid, patients could develop peritoneal fibrosis and ultrafiltration failure which compromises treatment efficacy and outcome, and fibrosis is the major cause of peritoneal dialysis (PD) withdraw among patients. METHODS: Twenty-one male WISTAR rats were randomly assigned to three groups, namely saline group, standard peritoneal dialysis fluid (PDF) group, and panax notoginseng saponins (PNS) group. Peritoneal fibrosis was induced by daily injection of PDF for 4 weeks. After execution, multiple histological techniques including HE and Masson's trichrome staining and transmission electron microscopy (TEM) were applied to observe the pathological changes and concentrations of multiple cytokines may involve in the process of fibrosis were determined by enzyme-linked immune sorbent assay (ELISA). Biochemistry parameters were determined by automated chemistry analyzer. RESULTS: PNS can significantly inhibit the expression of transforming growth factor beta (TGF-ß1), connective tissue growth factor (CTGF), and monocyte chemoattractant protein (MCP-1) in the peritoneum of rats. Furthermore, pathological damages, including extracellular matrix deposition, vascularization, and fibroblast, were ameliorated in PNS group when being compared with standard PDF group. Peritoneal functions were improved by regular PNS treatment with significantly elevated ultrafiltration. CONCLUSION: PNS is capable of improving peritoneal function in subjects with PDF exposure and can possibly applied in patients with PD after further verification.

Comparing the host tissue response and peritoneal behavior of composite meshes used for ventral hernia repair.

BACKGROUND: The use of a prosthetic material is the best treatment option for ventral hernia repair; one of the most frequently performed abdominal surgery procedures. This preclinical study compares the behavior of a new mesh (Parietex composite ventral patch [Ptx]) with that of two existing meshes used for ventral hernia repair. MATERIALS AND METHODS: Fifty-four New Zealand White rabbits (3000 g) were used in an experimental model of umbilical hernia repair (diameter 1.5 cm). The materials tested were: Ventralex ST hernia patch (Vent) (Bard Davol Inc, Warwick, RI) (n = 18); Proceed ventral patch (Ethicon, Somerville, NJ) (PVP) (n = 18) and Ptx (Covidien, Sofradim, Trevoux, France) (n = 18). At 3, 7, 14 d, and 6 wk after implant, peritoneal behavior and adhesion formation were assessed by sequential laparoscopy. Mesh mesothelial cover was determined by scanning electron microscopy. Host tissue ingrowth (collagens I and III) and the macrophage response were assessed by immunohistochemical labeling. Animals were euthanized at 2, 6 wk, and 6 mo after surgery. Data were compared using the Mann-Whitney U test. RESULTS: Adhesion formation from 3 d-6 wk was significantly greater (P < 0.05) for PVP compared with Vent or Ptx. Three encapsulated PVP implants showed "tissue-integrated" adhesions affecting the intestinal loops. All three implant types showed similar patterns of collagen l and III deposition. The PVP mesh elicited the greater macrophage response both at 2 wk and 6 mo. CONCLUSIONS: Ptx and Vent showed excellent mesothelialization, which led to minimum adhesion formation. The appropriate tissue integration of Ptx in the parietal neoperitoneum is likely attributable to its deployment system.

Accumulation of melanin in the peritoneum causes black abdomens in broilers.

A suspected case of localized visceral hyperpigmentation was described for a breed of broiler in China. Using optical microscopy, the accumulation of pigments in the abdominal skin and visceral peritoneum was observed. Electron microscopy was used to further study the ultrastructure of the pigmented peritoneum, and pigment granules resembling melanosomes at different stages were found, and melanocytes were present in this tissue. Infrared spectroscopy was used to analyze the physical-chemical properties of pigments extracted from these broilers. Using synthetic melanin as a reference and the melanin from the peritoneum of Silkie fowls as a control, the pigments in the peritonea of these broilers were found to be melanin, and it had a chemical structure similar to that of melanin from the Silkie fowl peritoneum. In this way, the black abdomens of these broilers were found to have been caused by accumulation of melanin produced by melanocytes in visceral peritonea.

Peritoneal Submesothelial Stromal Cells Support Hematopoiesis and Differentiate into Osteogenic and Adipogenic Cell Lineages.

The peritoneum is a thin membrane that covers most of the abdominal organs, composed of a monolayer of mesothelial cells and subjacent submesothelial loose connective tissue. Cells from the peritoneal wall are correlated with peritoneal fibrosis and epithelial-to-mesenchymal transition. However, the distinct involvement of mesothelial or submesothelial cells in such phenomena is still not clear. Here, we propose a new strategy to obtain stromal cells from anterior peritoneal wall explant cultures. These cells migrated from peritoneal tissues and proliferated in vitro for 4 weeks as adherent fibroblast-like cells. Optical and electronic microscopy analyses of the fragments revealed a significant submesothelial disorganization. The obtained cells were characterized as cytokeratin- vimentin+ laminin+ α-smooth muscle actin+, suggesting a connective tissue origin. Moreover, at the third passage, these stromal cells were CD90+CD73+CD29+Flk-1+CD45-, a phenotype normally attributed to cells of mesenchymal origin. These cells were able to support hematopoiesis, expressing genes involved in myelopoiesis (SCF, G-CSF, GM-CSF, IL-7 and CXCL-12), and differentiated into osteogenic and adipogenic cell lineages. The methodology demonstrated in this work can be considered an excellent experimental model to understand the physiology of the peritoneal wall in healthy and pathological processes. Moreover, this work shows for the first time that submesothelial stromal cells have properties similar to those of mesenchymal cells from other origins.