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The peritoneal cavity (PerC) is an important site for immune responses to infection and cancer metastasis. Yet few ligand-receptor axes are known to preferentially govern immune cell accumulation in this compartment. GPR34 is a lysophosphatidylserine (lysoPS)-responsive receptor that frequently harbors gain-of-function mutations in mucosa-associated B cell lymphoma. Here, we set out to test the impact of a GPR34 knock-in (KI) allele in the B-lineage. We report that GPR34 KI promotes the PerC accumulation of plasma cells (PC) and memory B cells (MemB). These KI cells migrate robustly to lysoPS ex vivo, and the KI allele synergizes with a Bcl2 transgene to promote MemB but not PC accumulation. Gene expression and labeling studies reveal that GPR34 KI enhances PerC MemB proliferation. Both KI PC and MemB are specifically enriched at the omentum, a visceral adipose tissue containing fibroblasts that express the lysoPS-generating PLA1A enzyme. Adoptive transfer and chimera experiments revealed that KI PC and MemB maintenance in the PerC is dependent on stromal PLA1A. These findings provide in vivo evidence that PLA1A produces lysoPS that can regulate GPR34-mediated immune cell accumulation at the omentum.

Background: Intraperitoneal irrigation with a low‐volume, high‐concentration local anaesthetic in laparoscopic cholecystectomy (LC) provides less pain relief. We investigated the impact of high‐volume, low‐concentration bupivacaine on postoperative pain and opioid requirement. Methods: Patients undergoing LC were randomised into Group B (20 mL of 0.5% bupivacaine in 480 mL normal saline) or Group S (500 mL of normal saline). Fifteen patients were included in both the groups but one patient was excluded from Group S because of bile duct injury. The primary outcome was Duration of Analgesia (DOA). The secondary outcomes were the Numeric Pain Rating Scale (NRS) at extubation, at 15 min, 30 min and 1, 2, 4, 8, 12 and 24 h. Cumulative rescue analgesics, incidence of postoperative nausea, vomiting and shoulder pain. Results: Mean (median/range) duration of analgesia was 6.45 ± 5.57 h (6/0.15–24) in Group B vs 3.18 ± 4.21 h (0.3/0.15–12) in Group S. Cumulative requirement of rescue analgesic was higher in saline group being 56.25 ± 33.92 mg for diclofenac and 83.57 ± 66.75 mg for tramadol vis‐à‐vis 40.9 ± 39.17 mg and 30.00 ± 52.78 mg, respectively, in bupivacaine group. Conclusion: Irrigation of the peritoneal cavity with high‐volume low‐concentration bupivacaine in LC increases the duration of analgesia and decreases the analgesic requirement in the postoperative period. Trial Registration: ClinicalTrials.gov identifier: CTRI/2019/02/017802 dated 25/02/2019. [ABSTRACT FROM AUTHOR]

The objective of this study is to compare the outcomes and complications of retroperitoneal and transperitoneal laparoscopic pyelolithotomy (RLP and TLP, respectively) in the treatment of large kidney stones. In this retrospective cohort effort, data of all patients who underwent laparoscopic pyelolithotomy for renal pelvic stone (N = 273) in three referral urology hospitals were retrieved. Operation duration, length of hospital stay, postoperative stone-free rate, hemoglobin (Hb) and creatinine (Cr) changes and complications were compared between the two groups before and after propensity score matching. A total of 199 TLP and 74 RLP cases were examined. Stone size was significantly higher in the TLP vs. RLP group (29.8 ± 10.9 vs. 26.5 ± 8.8 mm; P =.022). Length of operation and hospital stay were comparable (P =.672 and P =.396, respectively). Rate of conversion to open surgery, postoperative blood transfusion rate, postoperative urinary leakage, postoperative stone-free rate, Hb drop and Cr change were similar between the two groups (P =.348, 0.190, 0.828, 0.411, 0.780 and 0.134, respectively). Postoperative fever was significantly more prevalent in TLP compared to RLP (21.6% vs. 0.0%, respectively; P <.001). Propensity score matched analyses showed similar results in all aspects; particularly demonstrating higher postoperative fever in TLP compared to RLP (18.9% vs. 0.0%, respectively; P <.001). RLP can be considered as an alternative to TLP; especially owing to a lower chance of postoperative fever. [ABSTRACT FROM AUTHOR]

Introduction. Patients with surgical abdominal pathology requiring management with an open abdomen are susceptible to protein loss from the exposed cavity. The objective of this study was to characterize protein loss through two types of temporary abdominal closure. Methods. A prospective cohort study was carried out with critically ill patients managed during 2021 with an open abdomen using two types of temporary closure: Bogota bag and ABThera™. Serial intraoperative peritoneal fluid samples were collected (days 1, 3, and 5). Frequencies and averages were calculated and compared with the Chi square and Student’s t tests. Results. Twenty-five patients were included. The average protein loss in peritoneal fluid was higher with the ABThera™ system (44.38 g/L) compared to the Bogota bag (25.18 g/L; p-value=0.0185). During follow-up, a tendency to decrease the average protein lost by both systems was observed, but with ABThera™ an average of 15.47 gr/L more protein was lost, regardless of the nutritional status and protein intake received (p=0.042). There were no differences based on etiology leading to open abdomen management, surgical procedures performed, or Covid-19 infection status. Conclusions. The open abdomen represents an important source of protein loss, which is different depending on the type of temporary closure used. These losses should be considered in calculations of nutritional support in the intensive care unit. [ABSTRACT FROM AUTHOR]

Purpose The calculation of the intraperitoneal organ surface area is important for understanding their anatomical structure and for conducting basic and clinical studies on diseases related to the peritoneum. To measure the intraperitoneal surface area in a living body by applying artificial intelligence (AI) techniques to the abdominal cavity using computed tomography and to prepare clinical indicators for application to the abdominal cavity. Methods Computed tomography images of ten adult males and females with a healthy body mass index and ten adults diagnosed with colon cancer were analyzed to determine the peritoneal and intraperitoneal surface areas of the organs. The peritoneal surface was segmented and three-dimensionally modeled using AI medical imaging software. In addition to manual work, three-dimensional editing, filtering, and connectivity checks were performed to improve work efficiency and accuracy. The colon and small intestine surface areas were calculated using the mean length and diameter. The abdominal cavity surface area was defined as the sum of the intraperitoneal area and the surface areas of each organ. Results The mean peritoneal surface area of all participants was measured as 10,039±241 cm2 (males 10,224±171 cm2 and females 9,854±134 cm2). Males had a 3.7% larger peritoneal surface area than females, with a statistically significant difference (P

The non-neural cholinergic system plays a critical role in regulating immune equilibrium and tissue homeostasis. While the expression of choline acetyltransferase (ChAT), the enzyme catalyzing acetylcholine biosynthesis, has been well documented in lymphocytes, its role in the myeloid compartment is less understood. Here, we identify a significant population of macrophages (Mϕs) expressing ChAT and synthesizing acetylcholine in the resolution phase of acute peritonitis. Using Chat-GFP reporter mice, we observed marked upregulation of ChAT in monocyte-derived small peritoneal Mϕs (SmPMs) in response to Toll-like receptor agonists and bacterial infections. These SmPMs, phenotypically and transcriptionally distinct from tissue-resident large peritoneal macrophages, up-regulated ChAT expression through a MyD88-dependent pathway involving MAPK signaling. Notably, this process was attenuated by the TRIF-dependent TLR signaling pathway, and our tests with a range of neurotransmitters and cytokines failed to induce a similar response. Functionally, Chat deficiency in Mϕs led to significantly decreased peritoneal acetylcholine levels, reduced efferocytosis of apoptotic neutrophils, and a delayed resolution of peritonitis, which were reversible with exogenous ACh supplementation. Intriguingly, despite B lymphocytes being a notable ChAT-expressing population within the peritoneal cavity, Chat deletion in B cells did not significantly alter the resolution process. Collectively, these findings underscore the crucial role of Mϕ-derived acetylcholine in the resolution of inflammation and highlight the importance of the non-neuronal cholinergic system in immune regulation. [ABSTRACT FROM AUTHOR]

In the context of multimodal treatments for abdominal cancer, including procedures such as cytoreductive surgery and intraperitoneal chemotherapy, recurrence rates remain high, and long-term survival benefits are uncertain due to post-operative complications. Notably, treatment-limiting side effects often arise from an uncontrolled activation of the immune system, particularly peritoneally localized macrophages, leading to massive cytokine secretion and phenotype changes. Exploring alternatives, an increasing number of studies investigated the potential of plasma-activated liquids (PAL) for adjuvant peritoneal cancer treatment, aiming to mitigate side effects, preserve healthy tissue, and reduce cytotoxicity towards non-cancer cells. To assess the nontoxicity of PAL, we isolated primary human macrophages from the peritoneum and subjected them to PAL exposure. Employing an extensive methodological spectrum, including flow cytometry, Raman microspectroscopy, and DigiWest protein analysis, we observed a pronounced resistance of macrophages towards PAL. This resistance was characterized by an upregulation of proliferation and anti-oxidative pathways, countering PAL-derived oxidative stress-induced cell death. The observed cellular effects of PAL treatment on human tissue-resident peritoneal macrophages unveil a potential avenue for PAL-derived immunomodulatory effects within the human peritoneal cavity. Our findings contribute to understanding the intricate interplay between PAL and macrophages, shedding light on the promising prospects for PAL in the adjuvant treatment of peritoneal cancer. [ABSTRACT FROM AUTHOR]

Background & Aims: Patients with advanced cirrhosis often develop hepatic decompensation, which is accompanied by systemic inflammation and may eventually lead to acute-on-chronic liver failure. One important cause of systemic hyperinflammation is a dysregulated overshooting immune response in ascites in the abdominal cavity. In this study, we analyzed the role of CD8+ T cells in the ascites immune compartment. Methods: Peripheral blood and ascites fluid were collected from 50 patients with decompensated cirrhosis. Phenotype and functional responses of CD8+ T cells were analyzed, and obtained data were compared with each other as well as with healthy controls and patients with compensated cirrhosis. Results: High-dimensional flow cytometry revealed that CD8+ T cells are abundant in the ascites of patients with cirrhosis and exhibit a chronically activated bystander phenotype with innate-like functions. Indeed, we identified distinct CXCR6+CD69+ clusters of late effector memory CD8+ T cells that were rarely found in blood and correlated with clinical parameters of disease severity. Moreover, this CD8+ T-cell population was hyperresponsive to innate cytokines and exhibited cytokine-mediated bystander activation. Interestingly, the Janus kinase (JAK) inhibitor tofacitinib was able to effectively block bystander-activated CXCR6+CD69+ CD8+ T cells and significantly suppress effector molecule production. Conclusions: The results indicate that CXCR6+CD69+ CD8+ T cells in ascites are associated with disease severity and may contribute to inflammation in patients with decompensated cirrhosis, suggesting that targeted inhibition of this immune cell subset may be a viable therapeutic option. Impact and Implications: Patients with advanced cirrhosis often develop hepatic decompensation, which is accompanied by systemic inflammation and eventually leads to acute-on-chronic liver failure. One important cause of systemic hyperinflammation is a dysregulated overshooting immune response in ascites in the abdominal cavity. In this study, we demonstrate that CXCR6+CD69+ CD8+ T cells are abundant in the ascites of patients with cirrhosis, exhibit a chronically activated bystander phenotype, and correlate with clinical parameters of disease severity. Moreover, we show that the Janus kinase (JAK) inhibitor tofacitinib can effectively block these bystander-activated CXCR6+CD69+ CD8+ T cells, suggesting that targeted inhibition of this immune cell subset may be a potential therapeutic strategy. Clinical trial number: Prospective registry: INFEKTA (DRKS00010664).

Lymphangiomas in the peritoneal cavity are rare in adults, with most cases occurring in children. We present the case of a 49-year-old woman who was admitted with severe lower abdominal pain. The diagnostic assessment revealed a multiloculated cystic structure in the mesentery of the distal ileum, suggesting a lymphangioma. The patient underwent laparotomy and resection, with successful removal of the mass. Histopathological examination confirmed the diagnosis of intestinal lymphangioma, a rare benign vascular neoplasm of the small bowel. Postoperatively, the patient experienced resolution of postoperative ileus and mild back and abdominal pain, with no complaints during follow-up. Awareness of this uncommon condition is crucial for accurate diagnosis and appropriate treatment. Surgical resection, supported by radiological and histopathological investigations, is the primary treatment modality for symptomatic lymphangioma. Regular follow-up with imaging may be necessary to monitor recurrence. [ABSTRACT FROM AUTHOR]

The omentum is the predominant site of ovarian cancer metastasis, but it is difficult to remove the omentum in its entirety. There is a critical need for effective approaches that minimize the risk of colonization of preserved omental tissues by occult cancer cells. Normal saline (0.9% sodium chloride) is commonly used to wash the peritoneal cavity during ovarian cancer surgery. The omentum has a prodigious ability to absorb fluid in the peritoneal cavity, but the impact of normal saline on the omentum is poorly understood. In this review article, we discuss why normal saline is not a biocompatible solution, drawing insights from clinical investigations of normal saline in fluid resuscitation and from the cytopathologic evaluation of peritoneal washings. We integrate these insights with the unique biology of the omentum and omental metastasis, highlighting the importance of considering the absorptive ability of the omentum when administering agents into the peritoneal cavity. Furthermore, we describe insights from preclinical studies regarding the mechanisms by which normal saline might render the omentum conducive for colonization by cancer cells. Importantly, we discuss the possibility that the risk of colonization of preserved omental tissues might be minimized by using balanced crystalloid solutions for peritoneal washing. [ABSTRACT FROM AUTHOR]

Background: Primary infection has been questioned as the pathogenetic cause of acute appendicitis. We attempted to identify the bacteria involved and to investigate if their species, types, or combinations affected the severity of acute appendicitis in children. Methods: Samples from both the appendiceal lumen and the peritoneal cavity of 72 children who underwent appendectomy were collected to perform bacterial culture analysis. The outcomes were studied to identify if and how they were associated with the severity of the disease. Regression analysis was performed to identify any risk factors associated with complicated appendicitis. Results: Escherichia coli, Pseudomonas aeruginosa, and Streptococcus species were the most common pathogens found in the study population. The same microorganisms, either combined or separate, were the most common in the appendiceal lumen and the peritoneal cavity of patients with complicated appendicitis. Gram-negative bacteria and polymicrobial cultures in the peritoneal fluid and in the appendiceal lumen were associated with complicated appendicitis. Polymicrobial cultures in the peritoneal cavity presented a four times higher risk of complicated appendicitis. Conclusions: Polymicrobial presentation and Gram-negative bacteria are associated with complicated appendicitis. Antibiotic regimens should target the combinations of the most frequently identified pathogens, speculating the value of early antipseudomonal intervention. [ABSTRACT FROM AUTHOR]

In peritoneal cavity authors distinguish upper and lower stories, the vault (fornix) and the bottom (fundus). The upper storey is divided into four spaces: right and left parahepatic, pregastric and omental bursa. In the right and left parahepatic spaces we allocate suprahepatic and infrahepatic pouches. The lower (subcolic) storey of peritoneal cavity is subdivided into two parts: anterior, preomental fissure and posterior, retroomental space.

Ovarian cancer metastasis occurs primarily in the peritoneal cavity. Orchestration of cancer cells with various cell types, particularly macrophages, in the peritoneal cavity creates a metastasis-favorable environment. In the past decade, macrophage heterogeneities in different organs as well as their diverse roles in tumor settings have been an emerging field. This review highlights the unique microenvironment of the peritoneal cavity, consisting of the peritoneal fluid, peritoneum, and omentum, as well as their own resident macrophage populations. Contributions of resident macrophages in ovarian cancer metastasis are summarized; potential therapeutic strategies by targeting such cells are discussed. A better understanding of the immunological microenvironment in the peritoneal cavity will provide a stepping-stone to new strategies for developing macrophage-based therapies and is a key step toward the unattainable eradication of intraperitoneal metastasis of ovarian cancer. [ABSTRACT FROM AUTHOR]

Large peritoneal macrophages (LPMs) are long‐lived, tissue‐resident macrophages, formed during embryonic life, developmentally and functionally confined to the peritoneal cavity. LPMs provide the first line of defense against life‐threatening pathologies of the peritoneal cavity, such as abdominal sepsis, peritoneal metastatic tumor growth, or peritoneal injuries caused by trauma, or abdominal surgery. Apart from their primary phagocytic function, reminiscent of primitive defense mechanisms sustained by coelomocytes in the coelomic cavity of invertebrates, LPMs fulfill an essential homeostatic function by achieving an efficient clearance of apoptotic, that is crucial for the maintenance of self‐tolerance. Research performed over the last few years, in mice, has unveiled the mechanisms by which LPMs fulfill a crucial role in repairing peritoneal injuries and controlling microbial and parasitic infections, reflecting that the GATA6‐driven LPM transcriptional program can be modulated by extracellular signals associated with pathological conditions. In contrast, recent experimental evidence supports that peritoneal tumors can subvert LPM metabolism and function, leading to the acquisition of a tumor‐promoting potential. The remarkable functional plasticity of LPMs can be nevertheless exploited to revert tumor‐induced LPM protumor potential, providing the basis for the development of novel immunotherapeutic approaches against peritoneal tumor metastasis based on macrophage reprogramming. [ABSTRACT FROM AUTHOR]

Cystic echinococcosis is a zoonotic infection caused by the larva of Echinococcus granulosus, which is capable of invading several organs starting from the human intestine. There are several complications in cases of co-infection with the human immunodeficiency virus (HIV), which are conditioned by the immunosuppressive disease and have poor prognosis. This report aims to describe a case of multi-cystic peritoneal echinococcosis in a patient under antiviral treatment for HIV for almost ten years, who received albendazole, underwent surgery and progressed favorably. This would be the first Peruvian report of a person with HIV and cystic echinococcosis. [ABSTRACT FROM AUTHOR]

Immune system dysregulation is clinically evident in the pathogenesis of endometriosis (EMS). Changes in the dendritic cells (DCs) activity or phenotype may be involved in the implantation and growth of endometrial tissue outside the uterus in the disease. The TIM-3/Gal-9 axis is implicated in the development of immune tolerance. However, the knowledge about the exact role of this pathway in the EMS is extremely poor. In the present study, we evaluated the expression of Gal-9 on myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in the peripheral blood (PB) and peritoneal fluid (PF) of both EMS patients (n = 82) and healthy subjects (n = 10) via flow cytometry. We also investigated the concentrations of soluble Gal-9 and TIM-3 in the plasma and PF of EMS patients and the control group using ELISA. We showed significantly elevated percentages of mDCs-Gal-9+ and pDCs-Gal-9+, and significantly higher concentrations of the soluble form of Gal-9 and TIM-3 in the PF of EMS patients than in circulation. Our results led us to conclude that the accumulation of Gal-9 expressing mDCs and pDCs in the PF and high sTIM-3/Gal-9 production in the peritoneal cavity could represent the hallmark of immune regulation in EMS patients, which may augment the inflammatory process and development/maintenance of local immunosuppression. [ABSTRACT FROM AUTHOR]

Abstract Large peritoneal macrophages (LPMs) are long‐lived, tissue‐resident macrophages, formed during embryonic life, developmentally and functionally confined to the peritoneal cavity. LPMs provide the first line of defense against life‐threatening pathologies of the peritoneal cavity, such as abdominal sepsis, peritoneal metastatic tumor growth, or peritoneal injuries caused by trauma, or abdominal surgery. Apart from their primary phagocytic function, reminiscent of primitive defense mechanisms sustained by coelomocytes in the coelomic cavity of invertebrates, LPMs fulfill an essential homeostatic function by achieving an efficient clearance of apoptotic, that is crucial for the maintenance of self‐tolerance. Research performed over the last few years, in mice, has unveiled the mechanisms by which LPMs fulfill a crucial role in repairing peritoneal injuries and controlling microbial and parasitic infections, reflecting that the GATA6‐driven LPM transcriptional program can be modulated by extracellular signals associated with pathological conditions. In contrast, recent experimental evidence supports that peritoneal tumors can subvert LPM metabolism and function, leading to the acquisition of a tumor‐promoting potential. The remarkable functional plasticity of LPMs can be nevertheless exploited to revert tumor‐induced LPM protumor potential, providing the basis for the development of novel immunotherapeutic approaches against peritoneal tumor metastasis based on macrophage reprogramming.

The model flatworm Mesocestoides vogae proliferating stage of infection elicits immunosuppression in the host. It was used to investigate the effects of human leukocyte extract (DLE) alone and in combination with anthelmintic albendazole (ABZ) on the reduction in peritoneal infection, peritoneal exudate cells (PECs), their adherent counterparts, and peritoneal exudates after the termination of therapy. Balb/c mice were infected with the larvae of M. vogae. PECs and adherent macrophages were studied via flow cytometry, mRNA transcript levels, and immunofluorescence. The cytokine levels were measured via ELISA and larvae were counted. ABZ significantly reduced larval counts (581.2 ± 65, p < 0.001), but the highest reduction was observed after combined treatment with ABZ and DLE (389.2 ± 119, p < 0.001) in comparison with the control. Compared to an infected group, the proportions of CD11b+CD19- myeloid cells with suppressive ability decreased after albendazole (ABZ) in combination with DLE, which was the most effective in the elevation of B cells and CD11b+F4/80mid/highMHCIIhigh macrophages/monocytes (22.2 ± 5.4%). Transcripts of the M2 macrophage markers (arginase 1, FIZZ-1, and Ym-1) were downregulated after DLE and combined therapy but not after ABZ, and the opposite trend was seen for iNOS. This contrasts with reduced ex vivo NO production by LPS-stimulated PECs from DLE and ABZ+DLE groups, where adherent macrophages/monocytes had elevated transcripts of the INF-γ receptor and STAT1 and reduced expression of STAT3, STAT6, and IL-10. Each therapy differentially modulated transcription profiles and concentrations of IFN-γ, TNF-α, IL-12p40, IL-6, IL-10, and TGF-β cytokines. DLE strongly ameliorated ABZ-induced suppression of INF-γ and IL-12 and preserved downregulation for IL-4, IL-10, and TGF-β. Epigenetic study on adherent macrophages from infected mice showed that ABZ, ABZ-sulfoxide, and DLE could interact with the mRNA of examined markers in a dose-dependent pattern. Co-administration of DLE with ABZ seemed to augment the drug's larvicidal effect via modulation of immunity. In comparison with ABZ, combined therapy was the most effective in alleviating parasite-induced Th2/Treg/STAT3/STA6 directed immunosuppression by stimulating the Th1 cytokines, M1 macrophage polarization, and activation of the IFNγ/STAT1 signaling pathway. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to investigate the effect of spinal anesthesia which will be performed simultaneously with general anesthesia on the site of operation with the same pressure. Material and method: This study was conducted as a randomized, prospective clinical study on 40 patients who were randomly divided into two groups. Twenty women underwent general anesthesia (Group GA) and 20 women underwent spinal anesthesia with general anesthesia (Group SGA). For all cases, preoperative height, weight, waist circumference, body mass index (kg/m2), the distance between both spina iliaca anterior superior, the distance of the intersection of both ribs with an imaginary line drawn over the anterior axillary line, suprapubic bone‐umbilical, umbilical‐xiphoid, and suprapubic bone‐xiphoid distance from the midline of the abdomen were measured. Moreover, while the patient was lying in the neutral position on the operating table, the height of the highest point of the abdomen to the operating table was also measured. These measurements were repeated at intra‐abdominal pressure (IAP) 14 and 25 mmHg. The amount of intra‐abdominal insufflated CO2 was also recorded at IAP 14 and 25 mmHg. Results: When the intra‐abdominal insufflation volumes of both groups were compared at 14 and 25 mmHg, respectively, there was no statistical difference (p: 0.54, p: 0.40). When 14 and 25 mmHg were compared in all cases, a statistically significant difference was observed in other measurements except in xiphoid‐umbilical distance (p < 0.05). Conclusion: We found that spinal anesthesia combined with GA had no effect on the abdominal volume and anthropometric measurements in laparoscopic procedures. [ABSTRACT FROM AUTHOR]

The omentum is the predominant site of ovarian cancer metastasis, but it is difficult to remove the omentum in its entirety. There is a critical need for effective approaches that minimize the risk of colonization of preserved omental tissues by occult cancer cells. Normal saline (0.9% sodium chloride) is commonly used to wash the peritoneal cavity during ovarian cancer surgery. The omentum has a prodigious ability to absorb fluid in the peritoneal cavity, but the impact of normal saline on the omentum is poorly understood. In this review article, we discuss why normal saline is not a biocompatible solution, drawing insights from clinical investigations of normal saline in fluid resuscitation and from the cytopathologic evaluation of peritoneal washings. We integrate these insights with the unique biology of the omentum and omental metastasis, highlighting the importance of considering the absorptive ability of the omentum when administering agents into the peritoneal cavity. Furthermore, we describe insights from preclinical studies regarding the mechanisms by which normal saline might render the omentum conducive for colonization by cancer cells. Importantly, we discuss the possibility that the risk of colonization of preserved omental tissues might be minimized by using balanced crystalloid solutions for peritoneal washing.

Ascites is the accumulation of fluid in the peritoneal cavity, caused by a wide variety of entities, the most common is liver cirrhosis. In these patients, the development of ascites is the consequence of splanchnic vasodilation, a decrease in the effective circulating volume and activation of the sympathetic nervous system and the renin angiotensin-aldosterone system, in addition to a systemic inflammatory process. The diagnostic approach includes, in addition to clinical data suggestive of ascites and its specific causes, imaging studies (abdominal ultrasound is the initial method of choice, and can be complemented with tomography or magnetic resonance imaging) and laboratory studies, such as the serum-ascitic albumin gradient (which allows the distinction between causes related to portal hypertension versus oncological, infectious and other inflammatory ones, nephrotic syndrome, etc.), stains, cultures and cytology, among others. Some molecular biomarkers are under investigation. Management is diverse and depends on the specific cause. [ABSTRACT FROM AUTHOR]

ObjectiveTo investigate the association between intraperitoneal (IP) disease dissemination patterns, residual disease (RD), surgical complexity, and molecular subtypes in advanced high-grade serous ovarian cancer (HGSOC).Methods741 patients with operable stage III-IV HGSOC undergoing primary debulking surgery at Mayo Clinic from 1994 to 2011 were categorized into four mutually exclusive IP disease dissemination patterns: upper abdominal (60%), miliary (16%), lower abdominal (15%), and pelvic (9%). Surgical complexity was classified as high, intermediate, or low; RD status was defined as 0, 0.1-0.5, 0.6-1.0, or >1cm; molecular subtype assignments were derived from expression profiling of tumors from 334 patients.ResultsPatients with either miliary or upper abdominal dissemination patterns were less likely to achieve RD0 compared to patients with pelvic and lower abdominal dissemination patterns (25% vs. 9% and 62%, each P

The interaction between dendritic cells (DCs) and T cells mediated by the programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1)/programmed cell death ligand 2 (PD-L2) pathway is the most important point in regulating immunological tolerance and autoimmunity. Disturbances in the quantity, maturity, and activity of DCs may be involved in the implantation and growth of endometrial tissue outside the uterus in endometriosis (EMS). However, little is known about the role of the immune checkpoint pathways in EMS. In our study, we examined the expression of PD-L1/PD-L2 on myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in the peripheral blood (PB) and peritoneal fluid (PF) of both EMS patients (n = 72) and healthy subjects (n = 20) via flow cytometry. The concentration of soluble PD-L1 and PD-L2 in the plasma and PF of EMS patients and the control group were determined using ELISA. We demonstrated an elevated percentage of mDCs, mDCs and pDCs with the PD-L1or PD-L2 expression, and a higher concentration of the soluble forms of PD-L1 and PD-L2 in the PF than in the plasma of EMS patients. We conclude that the peritoneal cavity environment and the PD-1/PD-L1/PD-L2 axis may play an important role in the modulation of immune response and the development and/or progression of EMS. [ABSTRACT FROM AUTHOR]

In patients with pancreatic cancer (PC), the peritoneal cavity is the second-most common site of metastasis after the liver. Peritoneal macrophages (PMs) have been demonstrated to play a significant role in the peritoneal metastases of different cancers. Gemcitabine (GEM) is known to affect PC-associated immune cells, including macrophages. However, its effect on PMs and its possible clinical implication is yet to be investigated. In this study, mouse-derived PMs were treated with GEM ex vivo to analyze the polarization status. Production of GEM-induced reactive oxygen species (ROS) and reactive nitrogen species was evaluated using DCFH-DA, DAF-FM, and Griess assay. Antitumor effects of PMs on UN-KC-6141and UN-KPC-961 murine PC cells were evaluated in presence and absence of GEM in vitro. Similarly, effect of GEM on human THP-1 macrophage polarization and its tumoricidal effect was studied in vitro. Furthermore, the effect of GEM-treated PMs on peritoneal metastasis of UN-KC-6141 cells was evaluated in a syngeneic mouse model of PC. GEM upregulated M1 phenotype-associated molecular markers (Tnf-α and Inos) in vitro in PMs obtained from naïve mouse. Moreover, IL-4-induced M2-like PMs reverted to M1-like after GEM treatment. Co-culture of UN-KC-6141 and UN-KPC-961 cancer cells with PMs in the presence of GEM increased apoptosis of these cells, whereas cell death was markedly reduced after N-acetyl-l-cysteine treatment. Corroborating these findings co-culture of GEM-treated human THP-1 macrophages also induced cell death in MIAPaCa-2 cancer cells. GEM-treated PMs injected intraperitoneally along with UN-KC-6141 cells into mice extended survival period, but did not stop disease progression and mortality. Together, GEM induced M1-like polarization of PMs from naive and/or M2-polarized PMs in a ROS-dependent manner. GEM-induced M1-like PMs prompted cytotoxicity in PC cells and delayed disease progression in vivo. [ABSTRACT FROM AUTHOR]

Problem: NK cell and macrophage function are decreased in endometriosis, and the disease may involve reduced immune surveillance in the peritoneal cavity. NK cell cytotoxicity and migration ability (chemotaxis) are considered important; the former has been investigated, but the latter has not. Method of study: We compared chemotaxis of immunocompetent cells (NK cells, macrophages, T cells) in peritoneal fluid obtained during laparoscopy in 27 women with and 13 without endometriosis. Peripheral blood NK cells were also obtained by the peripheral blood antibody beads method. Micro‐cultured cells were examined by time‐lapse photography, and the mean migration speed per cell was calculated as the chemotaxis. We investigated the relationship between chemotaxis and endometriosis. Results: NK cell chemotaxis was significantly lower in the endometriosis group. Macrophages and lymphocytes were not significantly different between the groups. During menstruation, NK cell chemotaxis decreased in both groups. Postmenstrual chemotaxis was increased significantly in women without endometriosis but remained low in women with endometriosis. The Revised‐American Society for Reproductive Medicine score was not correlated with chemotaxis; in women with endometriosis, chemotaxis was decreased even at early stages. Peripheral blood NK cells showed no significant differences. Conclusions: In women with endometriosis, not only cytotoxicity but also chemotaxis by NK cells in peritoneal cavity is significantly decreased, and particularly chemotaxis is decreased throughout the menstrual cycle. Therefore, antigens in retrograde menstrual blood that enters the peritoneal cavity might be left unprocessed. Repetition of this immune process in the peritoneal cavity may lead to the onset and subsequent progression of endometriosis. [ABSTRACT FROM AUTHOR]

Peritoneal loose body (PLB) is a rare clinical entity. It is generally agreed that the most common origin of the loose bodies is appendix epiploica. We here report a case of PLB that looks like a “boiled egg,” which was misdiagnosed preoperatively as a lesion of hepatic origin and was confirmed by operation and postoperative pathology. PLBs are rare entities, a good understanding of their specific imaging features can help prevent misdiagnosis, but sometimes an accurate preoperative diagnosis is still difficult to achieve. Exploratory laparoscopy is a recommended method for management of PLBs.

Creating surgical access is a critical step in laparoscopic surgery. Surgeons have to insert a sharp instrument such as the Veress needle or a trocar into the patient's abdomen until the peritoneal cavity is reached. They solely rely on their experience and distorted tactile feedback in that process, leading to a complication rate as high as 14% of all cases. Recent studies have shown the feasibility of surgical support systems that provide intraoperative feedback regarding the insertion process to improve laparoscopic access outcomes. However, to date, the surgeons' requirements for such support systems remain unclear. This research article presents the results of an explorative study that aimed to acquire data about the information that helps surgeons improve laparoscopic access outcomes. The results indicate that feedback regarding the reaching of the peritoneal cavity is of significant importance and should be presented visually or acoustically. Finally, a solution should be straightforward and intuitive to use, should support or even improve the clinical workflow, but also cheap enough to facilitate its usage rate. While this study was tailored to laparoscopic access, its results also apply to other minimally invasive procedures. [ABSTRACT FROM AUTHOR]

Background: Several studies have demonstrated the contribution of innate immune cells, including macrophages, in promoting systemic lupus erythematosus (SLE). Macrophages, one of the most abundant cell populations in the peritoneal cavity, are considered multifunctional cells with phenotypic plasticity. However, the functional properties of peritoneal macrophages in steady-state and during the progression of SLE remain poorly defined. Methods and results: Using the [NZB × NZW]F1 (BWF1) murine model of SLE, we analyzed the phenotype and function of peritoneal macrophages during the disease's onset. We found a higher frequency of peritoneal macrophages and B1a cells in BWF1-diseased mice than age-matched controls. Additionally, macrophages from diseased animals expressed lower levels of CD206, MHC-II, and Sirpα. RNAseq analysis identified 286 differentially expressed genes in peritoneal macrophages from diseased-BWF1 mice compared to control mice. Functional experiments demonstrate that peritoneal macrophages from diseased-BWF1 mice secrete higher levels of pro-inflammatory cytokines when activated with TLR7 and TLR9 agonists, and they were less efficient in suppressing the activation and proliferation of peritoneal LPS-activated B cells. These data demonstrate that peritoneal macrophages from BWF1-diseased mice present phenotypic and functional alterations shifting to a more pro-inflammatory state. Conclusions: The increase of macrophages with an altered phenotype and function together with the accumulation of B1a cells in the peritoneal cavity of diseased-BWF1 mice may promote the progression of the disease. Advancing awareness of the role and phenotype of peritoneal macrophages in SLE may contribute to a better understanding of these types of diseases and the development of novel therapies. [ABSTRACT FROM AUTHOR]

Infection is restrained by the concerted activation of tissue-resident and circulating immune cells. Whether tissue-resident lymphocytes confer early antiviral immunity at local sites of primary infection prior to the initiation of circulating responses is not well understood. Furthermore, the kinetics of initial antiviral responses at sites of infection remain unclear. Here, we show that tissue-resident type 1 innate lymphoid cells (ILC1) serve an essential early role in host immunity through rapid production of interferon (IFN)-γ following viral infection. Ablation of Zfp683-dependent liver ILC1 lead to increased viral load in the presence of intact adaptive and innate immune cells critical for mouse cytomegalovirus (MCMV) clearance. Swift production of interleukin (IL)-12 by tissue-resident XCR1+ conventional dendritic cells (cDC1) promoted ILC1 production of IFN-γ in a STAT4-dependent manner to limit early viral burden. Thus, ILC1 contribute an essential role in viral immunosurveillance at sites of initial infection in response to local cDC1-derived proinflammatory cytokines.

Encapsulation of human embryonic stem-cell-differentiated beta cell clusters (hES-βC) holds great promise for cell replacement therapy for the treatment of diabetics without the need for chronic systemic immune suppression. Here, we demonstrate a nanoporous immunoprotective polymer thin film cell encapsulation device that can exclude immune molecules while allowing exchange of oxygen and nutrients necessary for in vitro and in vivo stem cell viability and function. Biocompatibility studies show the device promotes neovascular formation with limited foreign body response in vivo. The device also successfully prevented teratoma escape into the peritoneal cavity of mice. Long-term animal studies demonstrate evidence of engraftment, viability, and function of cells encapsulated in the device after 6 months. Finally, in vivo study confirms that the device was able to effectively immuno-isolate cells from the host immune system.

Abstract Obturator hernia (OH) is a relatively rare abdominal wall hernia with a high mortality rate. The diagnosis of OH is challenging because of symptomatic variations and spontaneous reduction in hernia on imaging. An 89‐year‐old woman presented to our emergency department with pain in the abdomen and right groin. Computed tomography (CT) revealed an incarcerated small bowel in the gap between the obturator externus and pectineus (OE‐P gap). Symptoms disappeared after manual reduction. She experienced these same symptoms intermittently during the past year and underwent abdominal CT 4 times after disappearance of symptoms. The CT scans at each previous visit showed an enlarged OE‐P gap (an average of 80 mm) compared with the asymptomatic side (an average of 34 mm). An enlarged OE‐P gap on CT images taken after disappearance of symptoms could be a sign of spontaneously reduced OH.

Background: Primary infection has been questioned as the pathogenetic cause of acute appendicitis. We attempted to identify the bacteria involved and to investigate if their species, types, or combinations affected the severity of acute appendicitis in children. Methods: Samples from both the appendiceal lumen and the peritoneal cavity of 72 children who underwent appendectomy were collected to perform bacterial culture analysis. The outcomes were studied to identify if and how they were associated with the severity of the disease. Regression analysis was performed to identify any risk factors associated with complicated appendicitis. Results: Escherichia coli, Pseudomonas aeruginosa, and Streptococcus species were the most common pathogens found in the study population. The same microorganisms, either combined or separate, were the most common in the appendiceal lumen and the peritoneal cavity of patients with complicated appendicitis. Gram-negative bacteria and polymicrobial cultures in the peritoneal fluid and in the appendiceal lumen were associated with complicated appendicitis. Polymicrobial cultures in the peritoneal cavity presented a four times higher risk of complicated appendicitis. Conclusions: Polymicrobial presentation and Gram-negative bacteria are associated with complicated appendicitis. Antibiotic regimens should target the combinations of the most frequently identified pathogens, speculating the value of early antipseudomonal intervention.

The development and persistence of antibody secreting cells (ASC) after antigenic challenge remain inadequately understood in teleosts. In this study, intraperitoneal (ip) injection of Atlantic salmon (Salmo salar) with salmonid alphavirus (WtSAV3) increased the total ASC response, peaking 3–6 weeks post injection (wpi) locally in the peritoneal cavity (PerC) and in systemic lymphoid tissues, while at 13 wpi the response was only elevated in PerC. At the same time point a specific ASC response was induced by WtSAV3 in PerC and systemic tissues, with the highest frequency in PerC, suggesting a local role. Inactivated SAV (InSAV1) induced comparatively lower ASC responses in all sites, and specific serum antibodies were only induced by WtSAV3 and not by InSAV1. An InSAV1 boost did not increase these responses. Expression of immune marker genes implies a role for PerC adipose tissue in the PerC immune response. Overall, the study suggests the Atlantic salmon PerC as a secondary immune site and an ASC survival niche. • Infection with salmonid alphavirus induced a specific IgM secreting cell response. • The local B cell response in the peritoneal cavity was pronounced and long lasting. • Gene expression suggests peritoneal adipose tissue is involved in the B cell response. • The B cell response to inactivated virus was modest or absent, also after a boost. [ABSTRACT FROM AUTHOR]

Immune system dysregulation is clinically evident in the pathogenesis of endometriosis (EMS). Changes in the dendritic cells (DCs) activity or phenotype may be involved in the implantation and growth of endometrial tissue outside the uterus in the disease. The TIM-3/Gal-9 axis is implicated in the development of immune tolerance. However, the knowledge about the exact role of this pathway in the EMS is extremely poor. In the present study, we evaluated the expression of Gal-9 on myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in the peripheral blood (PB) and peritoneal fluid (PF) of both EMS patients (n = 82) and healthy subjects (n = 10) via flow cytometry. We also investigated the concentrations of soluble Gal-9 and TIM-3 in the plasma and PF of EMS patients and the control group using ELISA. We showed significantly elevated percentages of mDCs-Gal-9+ and pDCs-Gal-9+, and significantly higher concentrations of the soluble form of Gal-9 and TIM-3 in the PF of EMS patients than in circulation. Our results led us to conclude that the accumulation of Gal-9 expressing mDCs and pDCs in the PF and high sTIM-3/Gal-9 production in the peritoneal cavity could represent the hallmark of immune regulation in EMS patients, which may augment the inflammatory process and development/maintenance of local immunosuppression.

Intestinal parasitic nematodes affect a quarter of the world's population, typically eliciting prominent effector Th2-driven host immune responses. As not all infected hosts develop protection against reinfection, our current understanding of nematode-induced memory Th2 responses remains limited. Here, we investigated the activation of memory Th2 cells and the mechanisms driving early recall responses to the enteric nematode Heligmosomoides polygyrus in mice. We show that nematode-cured mice harbor memory Th2 cells in lymphoid and non-lymphoid organs with distinct transcriptional profiles, expressing recirculation markers like CCR7 and CD62-L in the mesenteric lymph nodes (mLN), and costimulatory markers like Ox40, as well as tissue homing and activation markers like CCR2, CD69 and CD40L in the gut and peritoneal cavity (PEC). While memory Th2 cells persist systemically in both lymphoid and non-lymphoid tissues following cure of infection, peritoneal memory Th2 cells in particular displayed an initial prominent expansion and strong parasite-specific Th2 responses during early recall responses to a challenge nematode infection. This effect was paralleled by a significant influx of dendritic cells (DC) and eosinophils, both also appearing exclusively in the peritoneal cavity of reinfected mice. In addition, we show that within the peritoneal membrane lined by peritoneal mesothelial cells (PeM), the gene expression levels of cell adhesion markers VCAM-1 and ICAM-1 decrease significantly in response to a secondary infection. Overall, our findings indicate that the host peritoneal cavity in particular harbors prominent memory Th2 cells and appears to respond directly to H. polygyrus by an early recall response via differential regulation of cell adhesion markers, marking the peritoneal cavity an important site for host immune responses to an enteric pathogen. [ABSTRACT FROM AUTHOR]

Abstract Background Here, Mesocestoides (M.) vogae infection in mice is proposed as a suitable experimental model for studying the immunity in the peritoneal cavity of mice. Methods To investigate the kinetics of immune parameters in M. vogae-infected mice, we detected, using flow cytometry, the expression of selected lymphoid and myeloid markers within the peritoneal cell population at day 0, 3, 6, 10, 14, 19, 25, 30 and 35 post-infection. Then, using ELISA, we analyzed the cytokine IFN-γ, TGF-β, IL-4 and IL-10 responses and the levels of anti-M. vogae IgG and IgM antibodies in the peritoneal lavage fluid. Cells isolated from the peritoneal cavity were subjected to further molecular analysis. To assess cell activation, peritoneal cells were exposed to LPS, and culture supernatants were collected and assayed for the level of cytokines and production of nitrite. Ly6C+ and Ly6G+ cells were isolated using MACS from the peritoneal cells at day 35 post-infection. Both MACS-isolated subsets were co-cultured with preactivated T cells to measure their suppressive capacity. Next, the role of parasite excretory-secretory antigens in induction of CD11b+ myeloid cells with the suppressive phenotype and the production of IL-10 was examined. Results In the peritoneal cavity an initial increase of CD11b+Gr-1+F4/80highMHC IIhigh cells, NK, NKT cells and CD8+ cytotoxic T cells was observed in the first week of infection. At day 14 post-infection, an increase in the number of myeloid CD11b+Gr-1+ cells was detected, and most of this cell population expressed low levels of F4/80 and MHC II in later stages of infection, suggesting the impairment of antigen-presenting cell functions, probably through the excretory-secretory molecules. Moreover, we confirmed that peritoneal Gr1+ cells (Ly6C+ and Ly6G+ population) are phenotypically and functionally consistent with myeloid-derived suppressor cells. Metacestode infection elicited high levels of IL-10 and upregulated STAT-3 in peritoneal cells. A higher level of IgM suggests that this isotype may be predominant and is involved in the host protection. Conclusions Mesocestoides vogae tetrathyridia induced the recruitment of immunosuppressive cell subsets, which may play a key role in the downregulation of immune response in long-term parasitic diseases, and excretory-secretory antigens seem to be the main regulatory factor.