Immunoregulation by type I interferons in the peritoneal cavity.

The peritoneal cavity, a fluid-containing potential space surrounding the abdominal and pelvic organs, is home to a rich network of immune cells that maintain tissue homeostasis and provide protection against infection. However, under pathological conditions such as peritonitis, endometriosis, and peritoneal carcinomatosis, the peritoneal immune system can become dysregulated, resulting in nonresolving inflammation and disease progression. An enhanced understanding of the factors that regulate peritoneal immune cells under both homeostatic conditions and in disease contexts is therefore required to identify new treatment strategies for these often life-limiting peritoneal pathologies. Type I interferons (T1IFNs) are a family of cytokines with broad immunoregulatory functions, which provide defense against viruses, bacteria, and cancer. There have been numerous reports of immunoregulation by T1IFNs within the peritoneal cavity, which can contribute to both the resolution or propagation of peritoneal disease states, depending on the specifics of the disease setting and local environment. In this review, we provide an overview of the major immune cell populations that reside in the peritoneal cavity (or infiltrate it under inflammatory conditions) and highlight their contribution to the initiation, progression, or resolution of peritoneal diseases. Additionally, we will discuss the role of T1IFNs in the regulation of peritoneal immune cells, and summarize the results of laboratory studies and clinical trials which have investigated T1IFNs in peritonitis/sepsis, endometriosis, and peritoneal carcinomatosis.

Free gas in the peritoneal cavity after colonoscopy. Indication for immediate action or incidental finding in imaging tests after uncomplicated colonoscopy? Literature review.

Colonoscopy is a routine diagnostic and therapeutic procedure. Along with the increase in the complexity of the procedures performed, the risk of complications increases. In 2017, WSES (World Society of Emergency Surgery) published the principles of safe colonoscopy. Intestinal perforation is one of the most common complications. The risk of perforation in treatment procedures such as mucosectomy or endoscopic dissection is significantly greater than the risk of diagnostic colonoscopy. The basic rule of the procedure in case of suspected perforation is close supervision over the patient's condition and the soonest possible repair of damage. The role of the endoscopist is not only early recognition, but also early treatment of damage. Immediate endoscopic treatment of lesions is an effective, final and acceptable management strategy. In patients who have undergone imaging diagnostics for another reason, free gas in the peritoneal cavity can be recognized. It does not have to mean the need for urgent surgical intervention. Patients with asymptomatic pneumoperitoneum after colonoscopy should, however, be treated as patients with suspected perforation of the large intestine and undergo careful clinical observation in accordance with WSES recommendations. Colonoscopy is a procedure with a risk of complications, which should be reported to patients qualified for endoscopy, but appropriate management reduces the risk of morbidity and mortality associated with this procedure.

End-expiratory lung volume assessment using helium and carbon dioxide in an experimental model of pediatric capnoperitoneum.

BACKGROUND: Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end-expiratory lung volume (EELV) assessment method based on CO2 dynamics ( EELV CO 2 ) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELVHe ). METHODS: Intra-abdominal pressure (IAP) was randomly varied between 0, 6, and 12 mm Hg with CO2 insufflation, while positive end-expiratory pressure (PEEP) levels of 3, 6, and 9 cm H2 O were randomly applied in eight anesthetized and mechanically ventilated chinchilla rabbits. Concomitant EELV CO 2 and EELVHe and lung clearance index (LCI) were obtained under each experimental condition. RESULTS: Significant correlations were found between EELV CO 2 and EELVHe before capnoperitoneum (r = .85, P < .001), although increased IAP distorted this relationship. The negative influence of IAP was counteracted by the application of PEEP 9, which restored the correlation between EELV CO 2 and EELVHe and resulted in 100% concordance rate between the methods regarding changes in lung volume. EELVHe and LCI showed a curvilinear relationship, and an EELVHe of approximately 20 mL kg-1 , determined with a receiver operating characteristic curve, was associated with near-normal LCI values. CONCLUSION: In this animal model of pediatric capnoperitoneum, reliable assessment of changes in EELV based on EELV CO 2 requires an open lung strategy, defined as EELV above approximately 20 mL kg-1 .

A Giant Egg-like symptomatic Loose Body in the Peritoneal Cavity: A Case Report.

BACKGROUND: Peritoneal loose bodies are rare lesions that are usually found as an incidental finding during abdominal surgery. Large loose bodies, measuring more than 5 cm, are rare and only a few cases are reported in the literature. Peritoneal loose bodies are usually infarcted appendices epiploicae, which become detached and appear as a peritoneal loose body in the abdominal cavity. CASE PRESENTATION: We report here the first case, in the local Ethiopian context, of a giant "egg-like" loose peritoneal body measuring 7 × 6 cm found in a 50-year-old man who presented with a cramping abdominal pain and features of abdominal obstruction. The current hypothesis as regards these bodies and the diagnostic challenges is discussed. CONCLUSION: Small peritoneal loose bodies are common but giant and symptomatic ones', like the one discussed here, are very rare and a diagnostic challenge. And, in the context of intestinal obstruction, a high index of suspicion is needed in order to diagnose them.

Peritoneal contamination with ICG-stained cervical secretion as surrogate for potential cervical cancer tumor cell dissemination: A proof-of-principle study for laparoscopic hysterectomy.

INTRODUCTION: Intracorporal colpotomy during radical hysterectomy for cervical cancer is discussed to be a risk factor for peritoneal dissemination of tumor cells. It might lead to increased recurrence rates after laparoscopic radical hysterectomy compared with abdominal hysterectomy, as shown by the recent LACC study. Data on the frequency or mechanisms of peritoneal contamination are missing. We aimed to analyze peritoneal contamination of cervical secretion during intracorporal colpotomy with a novel indocyaningreen (ICG)-based technique. MATERIAL AND METHODS: In this prospective proof-of-principle study, patients undergoing routine laparoscopic or robot-assisted hysterectomy were selected. ICG was specifically applied to the cervical surface and routine surgery was performed. During colpotomy, pictures under white and fluorescence light were taken to evaluate frequency of contamination. RESULTS: By using cervically applied ICG we were able to visualize directly peritoneal contamination with cervical secretion during intracorporal colpotomy. We detected peritoneal contamination in 9/12 (75%) patients undergoing routine laparoscopic hysterectomy. Contamination of laparoscopic instruments occurred in 60% of the patients. When contamination occurred, it was routinely detectable during all steps of colpotomy. There were no adverse effects during surgery. CONCLUSIONS: Peritoneal contamination with cervical secretion frequently occurs during intracorporal colpotomy. This novel technique represents a promising tool for feasible and direct visualization of peritoneal contamination during colpotomy. The technique may be easily implemented in further studies on laparoscopic and abdominal hysterectomy and serve as a quality assessment tool for surgeons and surgical techniques.

Low-Fiber Intake Is Associated With High Production of Intraperitoneal Inflammation Biomarkers.

OBJECTIVE: Fiber intake influences disturbances in the gastrointestinal tract and is associated with systemic inflammation in the general population. Systemic and intraperitoneal inflammation play an important role in defining outcomes in peritoneal dialysis (PD), but the relationship between dietary fiber intake and inflammatory biomarkers has not yet been reported in the population on PD. The objective of the present study is to analyze whether or not fiber intake in patients on PD is associated with serum and intraperitoneal levels of inflammatory biomarkers. DESIGN AND METHODS: Adult and clinically stable PD patients were included in this observational and cross-sectional study. Fiber intake was assessed by means of a dietary survey and calculated using the DietPro program 5.6i. The population was divided into two groups according to the median fiber intake. We investigated interleukin (IL)-1ß, IL-6, tumor necrosis factor-α, monocyte chemoattractant protein-1 (MCP-1), B-cell-activating factor, and plasminogen-activator inhibitor-1 in both serum and peritoneal fluid. The latter was determined after a dwell time of 4 hours. RESULTS: Fifty-two patients (42% men; aged 53 ± 14 years, 36% diabetics) were evaluated. Low intake of dietary fiber was found in 90% of patients, with a median of 12.2 g per day (3.4-33.3). The group with the highest fiber intake presented lower intraperitoneal levels of IL-6, IL-8, and MCP-1. In contrast, only MCP-1 was lower in the serum of those who consumed more fiber. All the associations remained significant after adjustment for confounders with plasminogen-activator inhibitor-1 included. CONCLUSIONS: Patients on PD frequently present inadequate dietary fiber intake, which appears to have an association with the inflammatory response, particularly in the intraperitoneal component. Further prospective studies, evaluating whether or not a dietetic intervention with a focus on fiber intake affects these biomarkers and clinical outcomes, are essential to determine causality and clinical relevance.

Role of the peritoneal cavity in the prevention of postoperative adhesions, pain, and fatigue.

A surgical trauma results within minutes in exudation, platelets, and fibrin deposition. Within hours, the denuded area is covered by tissue repair cells/macrophages, starting a cascade of events. Epithelial repair starts on day 1 and is terminated by day 3. If repair is delayed by decreased fibrinolysis, local inflammation, or factors in peritoneal fluid, fibroblast growth starting on day 3 and angiogenesis starting on day 5 results in adhesion formation. For adhesion formation, quantitatively more important are factors released into the peritoneal fluid after retraction of the fragile mesothelial cells and acute inflammation of the entire peritoneal cavity. This is caused by mechanical trauma, hypoxia (e.g., CO2 pneumoperitoneum), reactive oxygen species (ROS; e.g., open surgery), desiccation, or presence of blood, and this is more severe at higher temperatures. The inflammation at trauma sites is delayed by necrotic tissue, resorbable sutures, vascularization damage, and oxidative stress. Prevention of adhesion formation therefore consists of the prevention of acute inflammation in the peritoneal cavity by means of gentle tissue handling, the addition of more than 5% N2O to the CO2 pneumoperitoneum, cooling the abdomen to 30°C, prevention of desiccation, a short duration of surgery, and, at the end of surgery, meticulous hemostasis, thorough lavage, application of a barrier to injury sites, and administration of dexamethasone. With this combined therapy, nearly adhesion-free surgery can be performed today. Conditioning alone results in some 85% adhesion prevention, barriers alone in 40%-50%.

Oxidative stress in the pelvic cavity and its role in the pathogenesis of endometriosis.

Endometriosis is a disorder associated with a general inflammatory response in the peritoneal cavity. Oxidative stress is a potential factor involved in the pathophysiology of this disease, and reactive oxygen species (ROS) are implicated in this process. Indeed, in healthy individuals, ROS and antioxidants are in balance, but when balance is tipped toward an overabundance of ROS, oxidative stress occurs and can impact the entire reproductive lifespan of a woman. Reactive oxygen species are intermediaries produced by normal oxygen metabolism but are known to have deleterious effects. Excessive release of ROS induces cellular damage and alters cellular function by regulating protein activity and gene expression, leading to harmful effects. To protect themselves, cells have developed antioxidant systems to limit production of ROS, inactivate them, and repair cell damage. Understanding of the control of hemoglobin, heme, and iron-induced redox balance in endometriosis led us to propose a number of hypotheses to explain why oxidative stress is induced in case of pelvic endometriosis. Erythrocytes, apoptotic endometrial tissue, and cell debris transplanted into the peritoneal cavity by menstrual reflux and macrophages have all been cited as potential inducers of oxidative stress. Erythrocytes are likely to release pro-oxidant and proinflammatory factors, such as hemoglobin and its highly toxic by-products heme and iron, into the peritoneal environment. Iron and heme are essential to living cells, but unless appropriately chelated, free iron, and to a lesser extent heme, play a key role in the formation of deleterious ROS.

Gigantic solitary fibrous tumour of extra-peritoneal space. A case report and review of the literature.

Solitary fibrous tumour (SFT) is a rare soft tissue tumour which belongs to fibroblastic/myofibroblastic group of tumours. The most often it appears in pleura, also in pericardium, internal organs, peritoneum and extraperitoenal space. SFT was first described as a new type of pleura's tumour by Klemperer and Rabin in 1931. The histogenesis of SFT's has been discussed for years suggesting its mesothelial origin. Recently, SFT has been classified as a mesenchymal fibroblastic tumour. We report a very rare case of 71-year old man suffering from gigantic solitary fibrous tumour of extraperitoneal space who underwent curative surgery in the Department of General, Gastroenterological and Oncologic Surgery in 2011.

[Clinical pathological conference: abdominal masses and purulent ascites].

A 91 year old patient presented with constipation, abdominal distension, weakness and anorexia lasting for two days. Computed tomography revealed multiple peritoneal masses with significant growth within days and local invasiveness without regard to anatomical boundaries. No lymphadenopathy or hepatosplenomegaly were found. Abdominal paracentesis showed 60,000 cells/mm3 presumed to be neutrophils. During follow-up, there were no clinical or radiographic signs of peritonitis. Trans-abdominal true-cut biopsy from the peritoneal masses was consistent with diffuse large B cell lymphoma germinal center B cell type, clinically presenting as peritoneal lymphomatosis. FISH cytogenetic study identified single BLC-6 gene in the tumor infiltrating lymphocytes. We speculated that this aberration in the patient's immune system cells contributed to this rare, unusual and aggressive lymphoma presentation in an otherwise non-immune compromised patient.

[The role of iron metabolism and oxidative stress in the pathogenesis of endometriosis]. / Udzial metabolizmu zelaza oraz stresu oksydacyjnego w patogenezie endometriozy.

Despite many years of extensive investigations and increasing number of studies, the pathogenesis of endometriosis remains unclear Accumulated data suggests that disrupted iron metabolism may induce oxidative stress in the peritoneal cavity of endometriosis patients.

Systemic and local impact of glucose and glucose degradation products in peritoneal dialysis solution.

The main osmotic agent used in the peritoneal dialysis (PD) solution is glucose because of its great osmotic power, simple metabolism, and safety. Once into the systemic circulation, however, glucose can be a cause for metabolic complications including hyperglycemia, obesity, and dyslipidemia. The glucose absorbed from peritoneal cavity leads to insulin resistance and hyperglycemia, which is associated with oxidative stress. Long-term exposure of peritoneal membrane to glucose in PD solution also has local effects such as functional and structural changes leading to peritoneal membrane failure. Moreover, the intraperitoneal glucose absorption induces conditions similar to postprandial hyperglycemia, which is a proven independent risk factor of coronary artery disease in patients with type 2 diabetes. Though speculative, glucose toxicity might explain a higher mortality of PD patients after the first few years compared with those on hemodialysis. Glucose degradation products (GDPs) induce apoptosis of peritoneal mesothelial cells (PMCs), renal tubular epithelial cells, and endothelial cells, and facilitating epithelial mesenchymal transition of PMCs. GDPs provide a stronger reactivity than glucose in the formation of advanced glycation end-products, a known cause for microvascular complications and arteriosclerosis. Unfortunately, clinical studies using a low-GDP PD solution have provided mixed results on the residual renal function, peritonitis, peritoneal membrane function, and mortality; consistent outcome data are not readily available at present.

Gas embolism in laparoscopic hepatectomy: what is the optimal pneumoperitoneal pressure for laparoscopic major hepatectomy?

Laparoscopic hepatectomy (LH) has become popular as a surgical treatment for liver diseases, and numerous recent studies indicate that it is safe and has advantages in selected patients. Because of the magnified view offered by the laparoscope under pneumoperitoneal pressure, LH results in less bleeding than open laparotomy. However, gas embolism is an important concern that has been discussed in the literature, and experimental studies have shown that LH is associated with a high incidence of gas embolism. Major hepatectomies are done laparoscopically in some centers, even though the risk of gas embolism is believed to be higher than for minor hepatectomy due to the wide transection plane with dissection of major hepatic veins and long operative time. At many high-volume centers, LH is performed at a pneumoperitoneal pressure less than 12 mmHg, and reports indicate that the rate of clinically severe gas embolism is low. However, more studies will be necessary to elucidate the optimal pneumoperitoneal pressure and the incidence of gas embolism during LH.

Neutralisation of peritoneal IL-17A markedly improves the prognosis of severe septic mice by decreasing neutrophil infiltration and proinflammatory cytokines.

PURPOSE: The current study aimed to elucidate the role of peritoneal fluid IL-17A in septic mice, and the effects of intraperitoneal or intravenous blockade of the IL-17A pathway by anti-IL17A antibody on survival, plasma, and peritoneal cavity cytokine profile in a murine caecal ligation and puncture (CLP) sepsis model. The main source of peritoneal fluid IL-17A in septic mice was identified. METHODS: Male C57BL/6 mice that underwent severe CLP or sham surgery were intraperitoneally or intravenously administered anti-IL17A antibodies or isotype antibodies. The survival rates were observed. IL-17A, TNF-α, and IL-6 cytokine levels were measured by ELISA. Surface and intracellular IL-17A immunofluorescence stains were detected by flow cytometry to identify the IL-17A-producing cells. RESULTS: The IL-17A level was elevated much higher and earlier in peritoneal fluid than in the blood of the CLP mice. The intraperitoneal IL-17A blockade more significantly protects against CLP-induced mortality than intravenous blockade because of decreased TNF-α and IL-6 levels both in peritoneal fluid and blood, neutrophil infiltration in the peritoneal cavity, and lung injury. γδ T lymphocytes were identified to be the main source of IL-17A in the peritoneal fluid of septic mice. CONCLUSIONS: The earlier and higher elevated IL-17A derived from γδ T cells in peritoneal fluid plays a critical role during polymicrobial severe sepsis and effect of intraperitoneal IL-17A antibody administration superior to intravenous administration on survival of severe CLP-induced septic mice. The intraperitoneal blockade of IL-17A decreases proinflammatory cytokine production, neutrophil infiltration, and lung injury, thereby improving septic mice survival, which provides a new potential therapy target for sepsis.

[Pathogenesis and management of refractory malignant ascites]. / Physiopathologie et prise en charge des ascites malignes réfractaires.

Malignant ascites are the cancer-associated accumulation of fluids in the peritoneal cavity. The neoplasms most frequently associated with ascites are ovarian, breast, colon, stomach and pancreas adenocarcinomas. Symptoms are abdominal distention, nausea, vomiting, anorexia, dyspnea and limbs oedemas. Several pathophysiological mechanisms might be implicated such as peritoneal carcinomatosis, lymphatic vessels' obstruction, portal hypertension or heart failure. Its diagnosis is most often performed in a context of already known neoplasia. Malignant ascites are associated with a pejorative evolution. Ascites which cannot be mobilized or show early recurrence and cannot be prevented by medical treatment are defined as refractory ascites. Therefore, management of refractory malignant ascites takes place in the context of palliative care and aims at improving the quality of life of these patients. This review lists the current data reported on the pathophysiology of malignant ascites and describes the present and future options for refractory malignant ascites management.

Intraperitoneal adhesions--an ongoing challenge between biomedical engineering and the life sciences.

Peritoneal adhesions remain a relevant clinical problem despite the currently available prophylactic barrier materials. So far, the physical separation of traumatized serosa areas using barriers represents the most important clinical strategy for adhesion prevention. However, the optimal material has not yet been found. Further optimization or pharmacological functionalization of these barriers could give an innovative input for peritoneal adhesion prevention. Therefore, a more complete understanding of pathogenesis is required. On the basis of the pathophysiology of adhesion formation the main barriers currently in clinical practice as well as new innovations are discussed in the present review. Physiologically, mesothelial cells play a decisive role in providing a frictionless gliding surface on the serosa. Adhesion formation results from a cascade of events and is regulated by a variety of cellular and humoral factors. The main clinically applied strategy for adhesion prevention is based on the use of liquid or solid adhesion barriers to separate physically any denuded tissue. Both animal and human trials have not yet been able to identify the optimal barrier to prevent adhesion formation in a sustainable way. Therefore, further developments are required for effective prevention of postoperative adhesion formation. To reach this goal the combination of structural modification and pharmacological functionalization of barrier materials should be addressed. Achieving this aim requires the interaction between basic research, materials science and clinical expertise.