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Infants undergoing congenital heart surgery (CHS) with cardiopulmonary bypass (CPB) are at risk of acute kidney injury (AKI) and fluid overload. We hypothesized that placement of a passive peritoneal drain (PPD) can improve postoperative fluid output in such infants. We analyzed 115 consecutive patients, age birth to 60 days, admitted to the PICU after CHS with CPB between 2012 and 2018. Patients who needed postoperative ECMO were excluded. Linear and logistic regression models compared postoperative fluid balances, diuretics administration, AKI, vasoactive-inotropic scores (VIS), time intubated, and length of stay after adjusting for pre/operative predictors including STAT category, bypass time, age, weight, and open chest status. PPD patients had higher STAT category (p = 0.001), longer CPB times (p = 0.001), and higher VIS on POD 1–3 (p ≤ 0.005 daily). PPD patients also had higher AKI rates (p = 0.01) that did not reach significance in multivariable modeling. There were no postoperative deaths. Postoperative hours of intubation, hospital length of stay, and POD 1–5 fluid intake did not differ between groups. Over POD 1–5, PPD use accounted for 48.8 mL/kg increased fluid output (95% CI [2.2, 95.4], p = 0.043) and 3.41 mg/kg less furosemide administered (95% CI [1.69, 5.14], p

Tissue-engineered vascular grafts (TEVGs) require strategies to allow graft remodeling but avoid stenosis and loss of graft mechanics. A variety of promising biomaterials and methods to incorporate cells have been tested, but intimal hyperplasia and graft thrombosis are still concerning when grafting in small-diameter arteries. Here, we describe a strategy using the peritoneal cavity as an "in vivo" bioreactor to recruit autologous cells to electrospun conduits, which can improve the in vivo response after aortic grafting. We focus on the methods for a novel hydrogel pouch design to enclose the electrospun conduits that can avoid peritoneal adhesion but still allow infiltration of peritoneal fluid and cells needed to provide benefits when subsequently grafting in the aorta.

Mouse models of bacterial sepsis are widely used in research to investigate the underlying molecular mechanisms of sepsis and to develop clinically useful therapeutic regimens. Three commonly used mouse sepsis models include (a) injection of bacterial endotoxin, (b) infusion of cultured bacteria, and (c) cecal ligation and puncture. Here we describe the induction of bacterial sepsis in mice by intraperitoneal injection of cultured live Escherichia coli cells. The severity of the sepsis can be regulated by the number of E. coli cells injected into the peritoneal cavity of mice.

B-1 cells are fetal-origin B lymphocytes with unique developmental and functional characteristics that can generate natural, polyreactive antibodies with important functions in tissue homeostasis and immune defense. While B-1 cell frequencies in bone marrow and secondary lymphoid tissues are low, relative high frequencies exist within peritoneal and pleural cavities of mice, including both CD5+ and CD5- B-1 cells. These cells represent B-1 reservoirs that, when activated, migrate to lymphoid tissues to secrete antibodies and/or cytokines. Here, we outline efficient methods for the extraction and magnetic isolation of CD5+ B-1 cells from the peritoneal and pleural cavities as well as the separation and phenotypic characterization of CD5+ and CD5- B-1 cells by flow cytometry.

Studying the pathophysiology of sepsis still requires animal models, and the mouse remains the most commonly used species. Here we discuss the "cecal slurry" (CS) model of polymicrobial, peritoneal sepsis and compare and contrast it to other commonly used methods. Among the different murine models of sepsis, cecal ligation and puncture (CLP), and not the CS, is often considered the "gold standard" to induce polymicrobial sepsis in laboratory animals. CLP is a well-described model involving a simple surgical procedure that closely mimics the clinical course of intra-abdominal sepsis. However, CLP may not be an option for experiments involving newborn pups, where the cecum is indistinguishable from small bowel, where differences in microbiome content may affect the experiment, or where surgical procedures/anesthesia exposure needs to be limited. An important alternative method is the CS model, involving the intraperitoneal injection of cecal contents from a donor animal into the peritoneal cavity of a recipient animal to induce polymicrobial sepsis. Furthermore, CS is an effective alternative model of intraperitoneal polymicrobial sepsis in adult mice and can now be considered the "gold standard" for experiments in neonatal mice.

The liver fluke, Fasciola hepatica, infects a wide range of mammals including humans and leads to chronic disease. Like other helminths, F. hepatica migrates and survives in the host tissues after penetrating the intestinal wall to enter the peritoneal cavity, and then migrates through the liver before finally inhabiting the bile ducts. To avoid the antihelminthic immune response during migration, F. hepatica releases excretory-secretory products (FhESP) that exert various immunomodulatory effects, such as alternative macrophage activation or programmed cell death induction. Here, we describe the currently available techniques for studying macrophage activation and apoptotic cell death triggered by purified FhESP originating from the adult F. hepatica fluke.

In order to sustain its zoonotic lifecycle, leptospires must adapt to growth within the host milieu. Signals encountered within the mammal also trigger regulatory programs required by Leptospira for the expression of virulence-related gene products. The complex transcriptional, antigenic, and physiological changes leptospires undergo within the mammal are collectively referred to as "host adaptation." In this chapter, we describe the procedures for the generation of host-adapted Leptospira spp. by cultivation within dialysis membrane chambers (DMCs) implanted in rat peritoneal cavities. In this model, Leptospira spp. diluted in EMJH medium are sequestered within sterile dialysis membrane tubing closed at both ends. The chamber then is surgically implanted within the peritoneal cavity of a rat and incubated for 7-10 days. During this period, leptospires are exposed to many, if not all, of the physiological and nutritional cues required for host adaptation while at the same time protected from clearance by host innate and adaptive immune defenses.

Phenotyping cells by flow cytometry is a powerful way to identify cell type and any morphological changes during cell culture. The staining procedure used in this chapter enables the characterization of mouse macrophages by a flow cytometry antibody panel which can be used for both bone marrow-derived macrophages (BMM) and macrophages derived from other tissues, such as the mouse spleen or peritoneal cavity. The surface and intracellular staining methods are versatile and can be applied to flow cytometry staining of several different cell types by changing the surface markers used with knowledge of which receptors are expressed on different cell types.