scholarly journals Modulation of microglial phenotypes improves sepsis-induced hippocampus-dependent cognitive impairments and decreases brain inflammation in an animal model of sepsis

2020 ◽  
Vol 134 (7) ◽  
pp. 765-776 ◽  
Author(s):  
Monique Michels ◽  
Mariane Abatti ◽  
Andriele Vieira ◽  
Pricila Ávila ◽  
Amanda Indalécio Goulart ◽  
...  
Keyword(s):  
Animal Model ◽  
Cecal Ligation ◽  
Brain Dysfunction ◽  
Brain Inflammation ◽  
Time Points ◽  
M2 Microglia ◽  
Microglial Phenotype ◽  
Cytokine Levels ◽  
Almost All

Abstract Background: In order to modulate microglial phenotypes in vivo, M1 microglia were depleted by administration of gadolinium chloride and the expression of M2 microglia was induced by IL-4 administration in an animal model of sepsis to better characterize the role of microglial phenotypes in sepsis-induced brain dysfunction. Methods: Wistar rats were submitted to sham or cecal ligation and perforation (CLP) and treated with IL-4 or GdCl3. Animals were submitted to behavioral tests 10 days after surgery. In a separated cohort of animals at 24 h, 3 and 10 days after surgery, hippocampus was removed and cytokine levels, M1/M2 markers and CKIP-1 levels were determined. Results: Modulation of microglia by IL-4 and GdCl3 was associated with an improvement in long-term cognitive impairment. When treated with IL-4 and GdCl3, the reduction of pro-inflammatory cytokines was apparent in almost all analyzed time points. Additionally, CD11b and iNOS were increased after CLP at all time points, and both IL-4 and GdCl3 treatments were able to reverse this. There was a significant decrease in CD11b gene expression in the CLP+GdCl3 group. IL-4 treatment was able to decrease iNOS expression after sepsis. Furthermore, there was an increase of CKIP-1 in the hippocampus of GdCl3 and IL-4 treated animals 10 days after CLP induction. Conclusions: GdCl3 and IL-4 are able to manipulate microglial phenotype in an animal models of sepsis, by increasing the polarization toward an M2 phenotype IL-4 and GdCl3 treatment was associated with decreased brain inflammation and functional recovery.

Upregulated PD-L1 delays human neutrophil apoptosis and promotes lung injury in an experimental animal model of sepsis

Blood ◽  
2021 ◽  
Author(s):  
Jia-feng Wang ◽  
Yun-peng Wang ◽  
Jian Xie ◽  
Zhen-zhen Zhao ◽  
Sahil Gupta ◽  
...  
Keyword(s):  
Animal Model ◽  
Lung Injury ◽  
Cecal Ligation ◽  
Human Neutrophils ◽  
Experimental Sepsis ◽  
Akt Phosphorylation ◽  
Effect Of Pd ◽  
Knockout Animals ◽  
Neutrophil Survival

PD-L1 is a ligand for PD-1 and its expression has been shown to be upregulated in neutrophils harvested from septic patients. However, the effect of PD-L1 on neutrophil survival and sepsis-induced lung injury remains largely unknown. Here we show PD-L1 expression negatively correlates with rates of apoptosis in human neutrophils harvested from patients with sepsis. Using co-immunoprecipitation assays on control neutrophils challenged with IFN-γ and LPS, we show PD-L1 complexes with the p85 subunit of PI3-K to activate AKT-dependent survival signaling. Conditional CRE/LoxP deletion of neutrophil PD-L1 in vivo further protected against lung injury and reduced neutrophil lung infiltration in a cecal ligation and puncture (CLP) experimental sepsis animal model. Compared to wild-type animals, PD-L1-deficient animals presented lower plasma levels of plasma TNF-α and IL-6 and higher IL-10 following CLP, and reduced seven-day mortality in CLP PD-L1 knockout animals. Taken together, our data suggest that increased PD-L1 expression on human neutrophils delays cellular apoptosis by triggering PI-3K-dependent AKT phosphorylation to drive lung injury and increase mortality during clinical and experimental sepsis.

scholarly journals DAP12 (KARAP) amplifies inflammation and increases mortality from endotoxemia and septic peritonitis

2005 ◽  
Vol 202 (3) ◽  
pp. 363-369 ◽  
Author(s):  
Isaiah R. Turnbull ◽  
Jonathan E. McDunn ◽  
Toshiyuki Takai ◽  
R. Reid Townsend ◽  
J. Perren Cobb ◽  
...  
Keyword(s):  
Septic Shock ◽  
Cytokine Production ◽  
Ex Vivo ◽  
Cecal Ligation ◽  
Wild Type ◽  
Macrophage Response ◽  
Cytokine Levels ◽  
Septic Peritonitis ◽  
Microbial Products

DAP12 (KARAP) is a transmembrane signaling adaptor for a family of innate immunoreceptors that have been shown to activate granulocytes and monocytes/macrophages, amplifying production of inflammatory cytokines. Contrasting with these data, recent studies suggest that DAP12 signaling has an inhibitory role in the macrophage response to microbial products (Hamerman, J.A., N.K. Tchao, C.A. Lowell, and L.L. Lanier. 2005. Nat. Immunol. 6:579–586). To determine the in vivo role for DAP12 signaling in inflammation, we measured the response of wild-type (WT) and DAP12−/− mice to septic shock. We show that DAP12−/− mice have improved survival from both endotoxemia and cecal ligation and puncture–induced septic shock. As compared with WT mice, DAP12−/− mice have decreased plasma cytokine levels and a decreased acute phase response during sepsis, but no defect in the recruitment of cells or bacterial control. In cells isolated after sepsis and stimulated ex vivo, DAP12 signaling augments lipopolysaccharide-mediated cytokine production. These data demonstrate that, during sepsis, DAP12 signaling augments the response to microbial products, amplifying inflammation and contributing to mortality.

scholarly journals Protective Effects of Human and Mouse Soluble Scavenger-Like CD6 Lymphocyte Receptor in a Lethal Model of Polymicrobial Sepsis

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Mario Martínez-Florensa ◽  
Marta Consuegra-Fernández ◽  
Fernando Aranda ◽  
Noelia Armiger-Borràs ◽  
Marianna Di Scala ◽  
...  
Keyword(s):  
Adjunctive Therapy ◽  
Cecal Ligation ◽  
Experimental Models ◽  
Polymicrobial Sepsis ◽  
Soluble Form ◽  
Protective Effects ◽  
Adeno Associated Virus ◽  
Time Points ◽  
Cytokine Levels ◽  
Human And Mouse

ABSTRACT Sepsis still constitutes an unmet clinical need, which could benefit from novel adjunctive strategies to conventional antibiotic therapy. The soluble form of the scavenger-like human CD6 lymphocyte receptor (shCD6) binds to key pathogenic components from Gram-positive and -negative bacteria and shows time- and dose-dependent efficacy in mouse models of monobacterial sepsis. The objective of the present work was to demonstrate the effectiveness of infusing mouse and human sCD6 by different systemic routes, either alone or as adjunctive therapy to gold standard antibiotics, in a lethal model of polymicrobial sepsis. To this end, C57BL/6 mice undergoing high-grade septic shock induced by cecal ligation and puncture (CLP; ≥90% lethality) were infused via the intraperitoneal (i.p.) or intravenous (i.v.) route with shCD6 at different doses and time points, either alone or in combination with imipenem/cilastatin (I/C) at a dose of 33 mg/kg of body weight every 8 h. Significantly reduced mortality and proinflammatory cytokine levels were observed by i.p. infusion of a single shCD6 dose (1.25 mg/kg) 1 h pre- or post-CLP. When using the i.v. route, mice survival was significantly extended by starting shCD6 infusion at later time points post-CLP (up to 6 h after CLP). Significant adjunctive effects on mouse survival were observed by i.p. or i.v. infusion of shCD6 in combination with i.p. I/C post-CLP. Similar results were obtained in mice expressing high sustained levels (5 to 10 μg/ml) of mouse sCD6 in serum by means of transduction with hepatotropic adeno-associated virus (AAV). Taken together, the data support the conserved antibacterial effects of human and mouse sCD6 and their use as adjunctive therapy in experimental models of complex and severe polymicrobial sepsis.

Abstract 5542: Role of Scavenger Receptor BI in Sepsis

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Ling Guo ◽  
Eric Smart ◽  
Xiangan Li
Keyword(s):  
Animal Model ◽  
American Heart Association ◽  
American Heart ◽  
Scavenger Receptor ◽  
Cecal Ligation ◽  
Heart Association ◽  
Wild Type ◽  
Scavenger Receptor Bi ◽  
Lps Challenge

Scavenger receptor BI (SR-BI) is a well-established HDL receptor that regulates plasma HDL cholesterol levels by selectively uptake cholesterol ester from HDL. We recently reported a novel function of SR-BI namely protection against endotoxin-induced animal death. Using a lipopolysaccharides (LPS) induced endotoxic animal model, we found that LPS challenge induced 90% fatality of SR-BI null mice while all the wild type littermates survived, indicating that SR-BI plays a pivotal role in protection against LPS toxicity in vivo. In the current studies, we determined whether SR-BI plays a protective role in sepsis using an established septic animal model (cecal ligation and puncture, CLP). We demonstrate that CLP treatment induced 100% fatality of SR-BI null mice (n=20) whereas only 21% fatality of wild type littermates (n=27) and 36% fatality of heterozygous littermates (n=30). Moreover, SR-BI null mice exhibited exaggerated and prolonged inflammatory response as shown by elevated proinflammatory cytokine levels in serum upon CLP treatment compared to wild type littermates. Further studies revealed that the plasma LPS levels were significantly higher in SR-BI null mice compared to wild type control mice, indicating that SR-BI is required for LPS clearance in sepsis. Our findings clearly demonstrate that SR-BI is a critical protective modulator in sepsis in mice, which may reveal a novel target for the intervention of sepsis. (Supported by grant from American Heart Association 0530241N) This research has received full or partial funding support from the American Heart Association, AHA National Center.

scholarly journals Hypertension as Three Systematic Dysregulations of Na+ Homeostasis in Terrestrial Mammal, and Salt in Gut Might Cause Brain Inflammation

2021 ◽  
Author(s):  
Mizuo Mifune ◽  
Yoshihiko Kanno
Keyword(s):  
Salt Intake ◽  
Metabolic Stress ◽  
Brain Dysfunction ◽  
Brain Inflammation ◽  
Detection Mechanism ◽  
Tissue Macrophage ◽  
Subcutaneous Tissues ◽  
Vascular Tonus ◽  
Salt Sensitive Hypertension

Although Na+ homeostasis in vivo is essential for mammals, it is known that excessive salt (NaCl) intake has played a major role in the development of hypertension. In vivo, there is a hormonal system, the renin-angiotensin-aldosterone system (RAAS), that specializes in regulating Na+ retention, especially the amount of Na+ in plasma. Na+ homeostasis in vivo has been achieved mainly by the RAAS, through regulation of vascular tonus (blood pressure) and Na+ handling in the kidney (Na+ diuresis). Recent studies have revealed a third mechanism of Na+ homeostasis in vivo: regulation of interstitial Na+ levels in tissues, such as subcutaneous tissues, by tissue macrophage immunity. In the pathogenesis of salt-sensitive hypertension, Recent research have been revealed that three molecular axes (Ang II - Rho/NOX-eNOS system, Aldosterone-rac1 -ENaC system, and tissue Na+ − TonEBP in macrophage -VEGF-c) are significantly involved in maintaining Na+ homeostasis in salt induced hypertension. Furthermore, the mechanism by which salt causes hypertension via the immune system (intestinal, local mucosal, and tissue immunity) has also been reported. In this article, we would like to propose that three molecular dysfunctions are involved in the development of salt-sensitive hypertension through three immunological mechanisms in the maintenance of Na+ homeostasis. Next, I would like to explain the importance of gut-RAAS and abnormality of intestinal microflora (dysbiosis) in salt-sensitive hypertension. It has been known that the metabolites (e.g., short-chain fatty acid neural amino) produced by microflora are deeply involved in central (CNS) and sympathetic nervous system (SNS) activity. In addition, we would like to explain of the importance of brain-RAAS and cerebral inflammation in salt-sensitive hypertension. Moreover, recent research have revealed that the detection-mechanism in the brain for Na+ concentration([Na+]) in vivo and in the tongue for [Na+] in diet. These finding suggests that excessive salt intake may cause brain dysfunction, most delicate organ, before the onset of salt sensitive hypertension, and may also destroy brain structure after the onset of salt sensitive hypertension. Thus, we would like to insist that excessive salt intake might not only induce hypertension, but also be toxic especially for brain. Finally, we would like to explain that The DASH diet (Dietary Approaches to Stop Hypertension) is one of the universal diets for adult human, not only by reducing salt, but also by reducing metabolic stress and improving of dysbiosis.

scholarly journals Preclinical Testing of Radiopharmaceuticals for the Detection and Characterization of Osteomyelitis: Experiences from a Porcine Model

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4221
Author(s):  
Aage Kristian Olsen Alstrup ◽  
Svend Borup Jensen ◽  
Ole Lerberg Nielsen ◽  
Lars Jødal ◽  
Pia Afzelius
Keyword(s):  
Animal Model ◽  
Animal Models ◽  
Porcine Model ◽  
Animal Experiments ◽  
Radioactive Tracers ◽  
The Individual ◽  
Selection Of

The development of new and better radioactive tracers capable of detecting and characterizing osteomyelitis is an ongoing process, mainly because available tracers lack selectivity towards osteomyelitis. An integrated part of developing new tracers is the performance of in vivo tests using appropriate animal models. The available animal models for osteomyelitis are also far from ideal. Therefore, developing improved animal osteomyelitis models is as important as developing new radioactive tracers. We recently published a review on radioactive tracers. In this review, we only present and discuss osteomyelitis models. Three ethical aspects (3R) are essential when exposing experimental animals to infections. Thus, we should perform experiments in vitro rather than in vivo (Replacement), use as few animals as possible (Reduction), and impose as little pain on the animal as possible (Refinement). The gain for humans should by far exceed the disadvantages for the individual experimental animal. To this end, the translational value of animal experiments is crucial. We therefore need a robust and well-characterized animal model to evaluate new osteomyelitis tracers to be sure that unpredicted variation in the animal model does not lead to a misinterpretation of the tracer behavior. In this review, we focus on how the development of radioactive tracers relies heavily on the selection of a reliable animal model, and we base the discussions on our own experience with a porcine model.

scholarly journals A32 EMPAGLIFOZIN IMPROVES GASTROINTESTINAL INFLAMMATION IN A MOUSE MODEL OF COLITIS

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 213-215
Author(s):  
K Madsen ◽  
H Dang ◽  
N Hotte ◽  
V Mocanu ◽  
M Ferdaoussi ◽  
...  
Keyword(s):  
Animal Model ◽  
Sglt2 Inhibitor ◽  
Direct Effects ◽  
Lipocalin 2 ◽  
Wild Type ◽  
Gut Inflammation ◽  
Beneficial Effects ◽  
Histological Score ◽  
Cytokine Levels ◽  
Gastrointestinal Inflammation

Abstract Background Empagliflozin (EMPA) is a highly selective sodium glucose cotransporter-2 (SGLT2) inhibitor and is increasingly being utilized as an antihyperglycemic agent in the management of type 2 diabetes. Interestingly, it has been demonstrated in human trials that EMPA treatment exerts potent cardioprotective effects by reducing cardiac inflammation independently of glycemic control. Further, EMPA has also been shown to suppress LPS-induced renal and systemic inflammation in an animal model. Based on these findings, we hypothesized that EMPA treatment may also be effective in reducing gut inflammation. Aims The aim of this study was to examine the effects of treatment with EMPA on gastrointestinal inflammation in an animal model of inflammatory bowel disease and to determine mechanistic insights regarding its direct effects on gut cytokine secretion. Methods Adult male and female IL-10-/- mice with established colitis were treated with a daily gavage of EMPA (10mg/kg; n=10) or vehicle (n=10) for 14 days. Disease activity was assessed by measurement of mouse weight, colonic weight and length, histological score, cytokine levels in colonic homogenate and lipocalin-2 levels in stool. To examine for possible direct effects of EMPA, colonic explants from wild-type (n=8) and IL-10-/- (n=8) mice were incubated with increasing doses of EMPA (0.1–5 µM) ± LPS (10µg/ml) for 2 hours and tissue levels of IL-1β and TNFα protein measured by ELISA. Results After 14 days EMPA treated IL-10-/- mice had a significant improvement in colonic inflammation as evidenced by decreased colonic weight to length ratio (p=0.019), decreased fecal lipocalin-2 (p=0.03), as well as decreased enterocyte injury (p=0.01), decreased lamina propria neutrophils (p=0.01) and decreased total histological score (p=0.006). EMPA treated mice also maintained their weight over the 14 days while untreated mice continued to lose weight (p=0.04). There were no significant differences in colonic homogenate levels of TNFα, IL-1β, or IL-6 or in blood glucose levels between EMPA-treated mice and controls. In addition, EMPA did not suppress levels of basal or LPS-induced TNFα and IL-1β in colonic explants from either wild-type or IL-10-/- mice suggesting that the beneficial effects in IL-10-/- mice were not due to direct effects of EMPA on colonic TNFα or IL-1β cytokine levels. Conclusions EMPA treatment dramatically improved histologic and fecal inflammatory markers and maintained body weight in adult IL-10-/- mice with established colitis. These findings suggest further investigations into the effects of EMPA in treating gut inflammation are warranted. Funding Agencies CAG, CIHR

scholarly journals A Novel Infection Protocol in Zebrafish Embryo to Assess Pseudomonas aeruginosa Virulence and Validate Efficacy of a Quorum Sensing Inhibitor In Vivo

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 401
Author(s):  
Pauline Nogaret ◽  
Fatima El El Garah ◽  
Anne-Béatrice Blanc-Potard
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Animal Model ◽  
Quorum Sensing ◽  
Drug Testing ◽  
Drug Efficacy ◽  
Embryo Viability ◽  
Immersion Method ◽  
Opportunistic Human Pathogen

The opportunistic human pathogen Pseudomonas aeruginosa is responsible for a variety of acute infections and is a major cause of mortality in chronically infected cystic fibrosis patients. Due to increased resistance to antibiotics, new therapeutic strategies against P. aeruginosa are urgently needed. In this context, we aimed to develop a simple vertebrate animal model to rapidly assess in vivo drug efficacy against P. aeruginosa. Zebrafish are increasingly considered for modeling human infections caused by bacterial pathogens, which are commonly microinjected in embryos. In the present study, we established a novel protocol for zebrafish infection by P. aeruginosa based on bath immersion in 96-well plates of tail-injured embryos. The immersion method, followed by a 48-hour survey of embryo viability, was first validated to assess the virulence of P. aeruginosa wild-type PAO1 and a known attenuated mutant. We then validated its relevance for antipseudomonal drug testing by first using a clinically used antibiotic, ciprofloxacin. Secondly, we used a novel quorum sensing (QS) inhibitory molecule, N-(2-pyrimidyl)butanamide (C11), the activity of which had been validated in vitro but not previously tested in any animal model. A significant protective effect of C11 was observed on infected embryos, supporting the ability of C11 to attenuate in vivo P. aeruginosa pathogenicity. In conclusion, we present here a new and reliable method to compare the virulence of P. aeruginosa strains in vivo and to rapidly assess the efficacy of clinically relevant drugs against P. aeruginosa, including new antivirulence compounds.

scholarly journals Development and in‐vivo Assessment of a Novel MRI‐Compatible Headframe System for the Ovine Animal Model

2021 ◽  
Author(s):  
Marco Trovatelli ◽  
Stefano Brizzola ◽  
Davide Danilo Zani ◽  
Antonella Castellano ◽  
Paola Mangili ◽  
...  
Keyword(s):  
Animal Model ◽  
In Vivo Assessment
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