LPS Infusion Research Articles

A new protocol for the induction of chronic mastitis with intramammary infusion of lipopolysaccharide in Balb/c mice

Mastitis is the inflammation of the mammary tissue and is commonly observed in farm animals worldwide. The problem causes severe financial losses in the dairy industry in terms of veterinary costs, milk disposal, and treatment expenses. Bacteria are the main actors in the etiology and cause acute and chronic inflammatory changes in the mammary tissue. Acute inflammatory changes are easily recognized clinically, and treatment is initiated immediately, but subacute inflammation progresses insidiously and leads to chronic inflammation with irreversible fibrotic changes. Standardized experimental models for the induction of acute mastitis in laboratory animals are available, and usually, infusion of bacteria or some bacterial structural components into mammary tissue is easily applied for this purpose. However, there are few studies on the induction of chronic mastitis with fibrotic changes, and the applications are relatively complex. In the submitted study, LPS was infused through the teat duct three times on days 0, 5, and 10 to induce chronic mastitis in mice. Tissues were sampled on days 1, 6, and 15 to evaluate histopathological changes. While severe neutrophil infiltrates, a component of acute inflammation, were observed on day 1, lymphocyte infiltrates increased on day 6, consistent with subacute inflammation. On day 15, lesions representing chronic mastitis, such as fibrosis and lymphocyte infiltration, were observed. A model similar to the lesions in chronic mastitis of dairy cattle was successfully and easily established by LPS infusion in mice.

Effects of Oxiris® Therapy on Cytokine Elimination after a LPS Infusion-An Experimental Animal Study.

The clinical effectiveness of Oxiris®, particularly in reducing cytokines, remains uncertain due to the limited data provided. This study explored and analyzed the application value of Oxiris® endotoxin adsorption technology in a large animal model. Pigs received an intravenous LPS infusion. Six animals were treated 2 h after the infusion with an Oxiris® hemadsorption using a pumpless extracorporeal technique for 6 h. Five animals served as controls. Cardiocirculatory parameters, hyperspectral analysis, and a panel of cytokines were measured. The lipopolysaccharide infusion induced sepsis-like inflammation with tachycardia, elevated pulmonary pressure, elevated lactate level, as well as elevated pro-inflammatory cytokines like interferon (IFN)-γ, interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-12 and tumor necrosis factor alpha (TNF-α). In addition, increases of anti-inflammatory cytokines like IL-1ra and IL-10 were found. After 3 and 6 h in both groups, pro-inflammatory cytokines were significantly reduced. No differences between the intervention and the control group could be detected after 3 and 6 h for IL-1β, IL-2, IL-6, IL-8, IL-12 and TNF-α, suggesting no effect of the Oxiris® filter on the elimination of elevated cytokines with a pumpless extracorporeal hemadsorption technique. The presented large animal model may be a promising option for studying the effects of hemadsorption techniques.

Ultrashort wave diathermy inhibits pulmonary inflammation in mice with acute lung injury in a HSP70 independent way: a pilot study.

Acute lung injury (ALI) is a clinical syndrome characterized by pulmonary inflammation. Ultrashort wave diathermy (USWD) has been shown to be effective at in inhibiting ALI inflammation, although the underlying mechanism remains unclear. Previous studies have demonstrated that USWD generates a therapeutic thermal environment that aligns with the temperature required for heat shock protein 70 (HSP70), an endogenous protective substance. In this study, we examined the correlation between HSP70 and USWD in alleviating lung inflammation in ALI. Forty-eight male C57BL/6 mice were randomly divided into control, model, USWD intervention (LU) 1, 2, and 3, and USWD preintervention (UL) 1, 2, and 3 groups (n = 6 in each group). The mice were pretreated with LPS to induce ALI. The UL1, 2, and 3 groups received USWD treatment before LPS infusion, while the LU1, 2, and 3 groups received USWD treatment after LPS infusion. Lung function and structure, inflammatory factor levels and HSP70 protein expression levels were detected. USWD effectively improved lung structure and function, and significantly reduced IL-1β, IL-10, TGF-β1, and TNF-α levels in both the USWD preintervention and intervention groups. However, HSP70 expression did not significantly differ across the experimental groups although the expression of TLR4 was significantly decreased, suggesting that USWD may have anti-inflammatory effects through multiple signaling pathways or that the experimental conditions should be restricted. Both USWD intervention and preintervention effectively reduced the inflammatory response, alleviated lung injury symptoms, and played a protective role in LPS-pretreated ALI mice. HSP70 was potentially regulated by USWD in this process, but further studies are urgently needed to elucidate the correlation and mechanism.

Sex-Based Differences in LPS-induced Rapid Myocardial Dysfunction

Background: Previous studies have indicated better myocardial responses with preserved cardiac function in female animals compared to males after LPS challenge; however, the mechanisms remain incompletely understood. Our published studies have revealed that TNFa substantially increased in heart tissue and serum following LPS. Females experienced less cardiac dysfunction than males during equivalent dose of TNFa infusion. Therefore, sex-related disparities in myocardial impairment could be due to an indirect/secondary outcome from LPS-induced inflammatory cytokines, like TNFa. To dissect the potential mechanism underlying myocardial reactions between males and females, we aim to determine any sex differences in LPS-caused direct effects on cardiac function using coronary infusion of LPS.
 
 Methods: Isolated hearts from aged-matched adult male and female mice were subjected to LPS infusion via Langendorff after >20-min equilibration (Eq), with left ventricular developed pressure (LVDP) continuously recorded. Dose responsive experiments with LPS at 2.5, 5.0, and 7.5 mg/kg of body weight were performed in male hearts. Significant depression of LVDP (>20% drop) after LPS infusion was considered rapid response to LPS. Female estrous cycle was determined via vaginal smear.
 
 Results: Male hearts infused with 5.0 and 7.5 mg/kg of LPS demonstrated significant depression of LV function. Males also experienced worse outcomes of LV function than females following 5.0 mg/kg of LPS infusion. A trend of earlier response to LPS occurred in male hearts compared to females. However, there were no significant differences in cardiac function between female groups in different estrous phases.
 
 Conclusion and Potential Impact: Our data demonstrates that male hearts exhibit higher sensitivity to LPS-induced rapid cardiac dysfunction compared to females, but estrogen may have little influence on LPS-induced rapid functional depression. The insight from our data can be used to better understand the differences between male and female outcomes to cardiac pathologies and insult.

NEUROPROTECTIVE EFFECT OF PALIPERIDONE IN LPS INDUCED ANIMAL MODEL OF AD

AbstractBackgroundAlzheimer’s disease is a progressive neurological condition, that impairs cognition and memory. Extracellular beta‐amyloid plaques and intracellular neurofibrillary tangle formation are the two hallmarks while cognitive decline, neurotransmitter deficit, neuroinflammation, mitochondrial dysfunction, decreased cerebral glucose uptake, and oxidative stress has been known to contribute to the pathogenesis of AD. The present study was designed to investigate the neuroprotective potential of Paliperidone on intracerebroventricular (i.c.v.) Lipopolysaccharide‐induced experimental dementia of Alzheimer’s type.MethodLPS was administered by the i.c.v route on 1st day of the study in rats. Paliperidone was administered (1mg/Kg and 2mg/kg/day i.p) from the 1st to 21st day in LPS‐infused rats. Morris water maze, open‐field test, and object recognition parameters were used to assess learning, memory, behavioral changes and locomotor activity in rats. LPS infusion rapidly causes neuroinflammation and oxidative‐nitrosative stress.ResultThese markers were determined in the cortical and hippocampal brain regions of rats. While paliperidone treatment attenuates the LPS‐induced behavioral and biochemical abnormalities in rats by reducing levels of Malondialdehyde (MDA), reduced glutathione (GSH), and increasing levels of catalase. The neurodegeneration in Hippocampus and cortex regions was observed through histopathological examination. The observed cognitive improvement following paliperidone in LPStreated rats may be due to its antioxidant and anti‐inflammatory activity and restoration of cholinergic functions.ConclusionOur results suggest the therapeutic potential of paliperidone in cognitive disorders such as AD. However, more investigations are required to evaluate the potential of paliperidone in boosting memory and cognition and preventing neuronal damage.

Abstract 317: Development of a Swine Model of Rapidly-Induced Septic Shock Using Single Lipopolysaccharide Infusion and Titratable Inhaled Nitric Oxide to Prevent Severe Pulmonary Vasoconstriction

Objective: A serious limitation of LPS-induced swine models of septic shock is severe pulmonary vasoconstriction triggered, in part, by the pulmonary release of thromboxane A2. Efforts to overcome this limitation have included a stepwise increase in LPS dosing, intravenous aspirin derivatives, and inhaled nitric oxide (NO). We studied the effects of titrated inhaled NO given coincident with rapid LPS-infusion aimed at inducing the key features of septic shock over a shorter time period. Methods: We developed a LabVIEW-controlled system for inhaled NO delivery and monitoring. Exploratory studies showed that an NO concentration of up to 300 ppm sufficed to prevent significant pulmonary vasoconstriction despite delivery of a full LPS dose (12.6 μg/kg) in 30 minutes. We used this approach in 6 male domestic pigs (39.2 - 41.1 kg) and assessed hemodynamic and metabolic effects over 6 hours. NO and LPS infusion were started concurrently. Fluid resuscitation and vasopressor therapy were guided by macrohemodynamic measurements using custom-developed LabVIEW-controlled closed-loop algorithms. Results: Shown are medians with IQ25 and IQ75. LPS infusion increased pulmonary vascular resistance from 112 [72, 127] at baseline to 213 [120, 313] dynes-sec/cm 5 after 20 minutes. NO (139 [131, 166] ml/min) rapidly blunted the effect preventing the mean pulmonary artery pressure from exceeding 30 mmHg, avoiding detrimental effects on right ventricular function throughout the experiment. NO was rapidly de-escalated over 30 minutes using a closed-loop algorithm developed to prevent the mean pulmonary artery pressure from exceeding 30 mmHg. Within 60 minutes of LPS infusion start, animals began to develop key features of septic shock including tachycardia, hypotension, and systemic vasodilation triggering fluid resuscitation and norepinephrine administration. Additionally, blood lactate increased from 1.06 [0.90, 1.45] at baseline to 4.14 [2.43, 8.78] mmol/l after 3 hours remaining stable for an additional hour and subsequently decreasing in 3 and increasing in the other 3 animals, with half of the animals surviving the 6-h period. Conclusion: We developed a swine model of rapidly-induced key features of septic shock useful to explore early septic shock management.

Progressive inflammation reduces high-frequency EEG activity and cortical dendritic arborisation in late gestation fetal sheep

BackgroundAntenatal infection/inflammation is associated with disturbances in neuronal connectivity, impaired cortical growth and poor neurodevelopmental outcomes. The pathophysiological substrate that underpins these changes is poorly understood. We tested the hypothesis that progressive inflammation in late gestation fetal sheep would alter cortical neuronal microstructure and neural function assessed using electroencephalogram band power analysis.MethodsFetal sheep (0.85 of gestation) were surgically instrumented for continuous electroencephalogram (EEG) recording and randomly assigned to repeated saline (control; n = 9) or LPS (0 h = 300 ng, 24 h = 600 ng, 48 h = 1200 ng; n = 8) infusions to induce inflammation. Sheep were euthanised 4 days after the first LPS infusion for assessment of inflammatory gene expression, histopathology and neuronal dendritic morphology in the somatosensory cortex.ResultsLPS infusions increased delta power between 8 and 50 h, with reduced beta power from 18 to 96 h (P < 0.05 vs. control). Basal dendritic length, numbers of dendritic terminals, dendritic arborisation and numbers of dendritic spines were reduced in LPS-exposed fetuses (P < 0.05 vs. control) within the somatosensory cortex. Numbers of microglia and interleukin (IL)-1β immunoreactivity were increased in LPS-exposed fetuses compared with controls (P < 0.05). There were no differences in total numbers of cortical NeuN + neurons or cortical area between the groups.ConclusionsExposure to antenatal infection/inflammation was associated with impaired dendritic arborisation, spine number and loss of high-frequency EEG activity, despite normal numbers of neurons, that may contribute to disturbed cortical development and connectivity.

Eucalcemia during lipopolysaccharide challenge in postpartum dairy cows: II. Calcium dynamics

Hypocalcemia induced by immune activation is a conserved response among mammals. Early postpartum cows will experience decreased circulating Ca concentrations following acute immune activation; however, the cause for decreased Ca concentration is unknown. Our objectives were to (1) describe Ca dynamics following an intravenous (IV) LPS challenge in early postpartum cows, and (2) compare inflammatory-induced changes in Ca dynamics between IV Ca-treated cows and control cows. Cows (n = 14, 8 ± 1 d in milk) were enrolled in a matched-pair randomized controlled design to receive IV Ca (IVCa) in a eucalcemic clamp for 12 h, or 0.9% NaCl (CTRL) following an IV LPS infusion (0.040 or 0.045 µg of LPS/kg of body weight over 1 h). During the 24 h following LPS infusion, circulating concentrations of parathyroid hormone and serotonin were measured, serum and urine samples were collected to calculate urinary fractional excretion of Ca (FECa), and fecal samples were collected to calculate Ca apparent digestibility (ADCa) using amylase-treated and ash-corrected undigested neutral detergent fiber after 240 h (uNDFom240) as an internal marker. Changes in Ca intake and milk Ca secretion were also quantified and compared with baseline values. Cows were fasted during challenge and dry matter intake was 20 ± 5% less than baseline values on the day of challenge and did not differ between groups. On the day of challenge, milk Ca concentration increased, but milk yield decreased such that total Ca secreted in milk did not change from baseline. Urine FECa was low overall, but an interaction of treatment and time was identified such that FECa increased in IVCa but decreased in CTRL. Concentrations of parathyroid hormone increased and serotonin decreased following challenge. Fecal dry matter decreased from baseline, but did not differ between 6, 12, and 24 h, and did not differ between groups. An interaction of treatment and time was identified for ADCa and apparent digestibility of dry matter such that digestibility was decreased in CTRL but not IVCa at 6 h. Acute immune activation induced hypocalcemia in CTRL, and although urinary Ca excretion was not a primary cause, it is unclear to what degree hypocalcemia was due to altered ADCa. Eucalcemia appeared to alter adaptations in Ca homeostasis during immune activation as FECa was increased in IVCa animals.

Oral Administration of Meloxicam and Flunixin Meglumine Have Similar Analgesic Effects After Lipopolysaccharide-Induced Inflammatory Response in Thoroughbred Horses.

Flunixin meglumine (FM), a nonselective cyclooxygenase (COX) inhibitor, is most frequently selected for the treatment of equine systemic inflammatory response syndrome (SIRS)/endotoxemia. However, FM has considerable adverse effects on gastrointestinal function. The aims of this study were to compare the effect of meloxicam (MX), a COX-2 selective inhibitor commonly used in equine clinical practice, with FM, and to investigate the potential for clinical application in horses with SIRS/endotoxemia. Fifteen horses were divided into three groups of five and orally administered MX (0.6 mg/kg), FM (1.1 mg/kg), or saline as placebo at 30 minutes after LPS challenge. Clinical parameters, including behavioral pain scores, were recorded and blood for clinical pathological data was collected at various times from 60 minutes before to 420 minutes after LPS infusion. The pain score were significantly lower in both the MX and FM groups than in the placebo group, with no significant difference between them. Body temperature was significantly lower in the MX and FM groups than in the placebo group. Heart rates and respiratory rates, hoof wall surface temperature, and leukocyte counts changed similarly between the MX and FM groups. TNF-α and cortisol were lower in the FM group than in the MX group. The results suggest that MX suppresses the inflammatory response after LPS infusion and has an analgesic effect similar to that of FM. Given the adverse effects of nonselective COX inhibitors, clinical application of MX may be beneficial in horses with SIRS/endotoxemia.

Short communication: evaluation of an endotoxin challenge and intraruminal bacterial inoculation model to induce liver abscesses in Holstein steers.

Holstein steers (n = 40; initial body weight [BW] = 96.0 ± 10.5 kg) were individually housed in a climate-controlled barn to evaluate potential models for the genesis of liver abscesses (LA). In this 2 × 2 factorial, steers were balanced by BW and randomly assigned to one of two treatments: 1) intravenous saline injection followed by intraruminal bacterial inoculation with Fusobacterium necrophorum subsp. necrophorum (1 × 109 colony forming unit [CFU]/mL) and Salmonella enterica serovar Lubbock (1 × 106 CFU/mL; CON; n = 20 steers); or 2) intravenous injection with 0.25 µg/kg BW of lipopolysaccharide (LPS; Escherichia coli O111:B4) followed by intraruminal bacterial inoculation of F. necrophorum subsp. necrophorum (1 × 109 CFU/mL) and S. enterica serovar Lubbock (1 × 106 CFU/mL; LBI; n = 20 steers) and 1 of 2 harvest dates (3 or 10 d post LPS infusion). Body weights were recorded on days -4, -1, 3, and 10, and blood was collected for hematology on days -4, 3, and 10, relative to LPS infusion on day 0. Intraruminal bacterial inoculation occurred on day 1. Steers from each treatment group were harvested at two different time points on day 3 or 10 to perform gross pathological examination of the lung, rumen, liver, LA (if present), and colon. Feed disappearance was less for LBI than CON (P < 0.01); however, BW did not differ (P = 0.33) between treatments. Neither treatment nor time differed for hematology (P ≥ 0.13), and no gross pathological differences were noted in the lung, liver, LA, or colon (P ≥ 0.25). A treatment × harvest date interaction was noted for ruminal pathology in which LBI had an increased percentage of abnormal rumen scores on day 3 (P < 0.01). These results suggest that an LPS challenge in combination with intraruminal bacterial inoculation of pathogens commonly isolated from LA was not sufficient to induce LA in steers within 3 or 10 d (P = 0.95) when compared to CON. Further evaluation is needed to produce a viable model to investigate the genesis and prevention of LA in cattle.

Maternal siRNA silencing of placental SAA2 mitigates preterm birth following intrauterine inflammation.

The placental inflammatory processes induced maternally result in preterm birth (PTB). Serum amyloid A (SAA) is a well-known biomarker of inflammation. The objective of this study was to investigate whether murine placental SAA isoforms (SAA1–4) participate in the mechanism of spontaneous PTB and whether maternal regulation of SAA production may serve as a therapeutic approach. During the gestation, all isoforms of SAA were detectable except SAA2. The mouse model of intrauterine inflammation was established using LPS infusion to the uterus. Following intrauterine inflammation, placental SAA2 increased significantly. Inhibition of Saa2, using siSaa2, markedly decreased PTB. The increased placental expression of pro-inflammatory cytokines Il1β, Il6, and Tnfα were downregulated by siSaa2 treatment. Maternal inhibition of Saa2 did not change the expression of Saa1–4 in the fetal brain. Explant inflammatory culture of placentas with siSaa2 showed similar results to our in vivo experiments. This study demonstrates the highly expressed placental SAA2 as a novel therapeutic target, and maternal administration of siRNA as a promising approach to alleviate PTB.

Mesenchymal stem cells target microglia via galectin-1 production to rescue aged mice from olfactory dysfunction

Olfactory loss has been considered as the earliest complication for the aging process while underlying mechanisms and therapeutic strategies remain unclear. Given the correlation between microglial activation and olfactory dysfunction, here we investigated whether the immunomodulatory action of mesenchymal stem cells (MSCs) can rescue the olfactory impairment in old mice. The intranasal delivery of MSCs limited microglial activation and neuronal apoptosis in the olfactory bulb (OB), leading to improvement in olfaction. MSCs down-regulated the proportion of CD86+ microglia and prevented the maturation of cathepsin S, one of the inflammatory mediators in olfactory impairment, via the suppression of p38 MAPK signaling. Notably, old astrocytes could not prevent excessive microgliosis because the endogenous production of Galectin-1 (Gal1), one of the key microglia regulators secreted by astrocytes, was not sufficiently upregulated in the aged brain despite the presence of reactive astrogliosis. Considering that Gal1 is known as a potent paracrine factor of MSCs, we investigated whether MSC-derived Gal1 could compensate for defective astrocyte function in terms of microglial regulation. MSCs and their culture supernatant (MSC-CM) could regulate the direction of microglial differentiation by impeding the polarization towards the pro-inflammatory M1 type; notably, a selective Gal1 inhibitor OTX008 could hinder this phenomenon, indicating that Gal1 is involved in immunomodulation exerted by MSCs. Also, acute microglial activation within the OB upon LPS infusion was attenuated by MSC-CM in a Gal1-dependent manner. Our study demonstrates the therapeutic benefit of MSCs on age-related olfactory dysfunction and suggests Gal1 as a key mediator of the anti-inflammatory action of MSCs.

НЕРВНЫЕ И ГУМОРАЛЬНЫЕ ПУТИ ВЛИЯНИЯ ЭНДОТОКСИНОВ КИШКИ НА ИНТЕРОЦЕПТИВНЫЕ РЕФЛЕКТОРНЫЕ РЕАКЦИИ

In acute experiments on rats, an increase and decrease in afferent activity in the mesenteric nerves of the intestine as well as vagus under the diaphragm, depending on the site of lipopolysaccharide (LPS, 10 μg) injection into the intestinal lumen, has been established. In addition, the effect of endotoxin on the gastrointestinal tract (GIT) is manifested in a reflex change in the efferent nerve impulses. The reactions of the cervical sympathetic, splenic, cranial and caudal mesenteric nerves as well as vagus under the diaphragm are represented by an increase or decrease in the spontaneous activity of efferent fibers and depend on the zone of LPS infusion in the GIT. In general, inhibitory responses to endotoxin predominate, especially in the mesenteric nerves. According to experiments, the reflex responses of sympathetic efferent fibers caused by balloon distension of the colon are regularly weakened or completely suppressed after the infusion of LPS into the lumen of this organ. Under conditions of complete external decentralization of the GIT by transection of the vagus, all mesenteric nerves and the colon at the border with the rectum, the effects of modulation of the activity of both peripheral and central nervous structures under the influence of LPS are preserved due to the humoral pathway included in the complex neurotransmitter mechanism for controlling autonomic functions.

Fractalkine deficiency attenuates LPS-induced acute kidney injury and podocyte apoptosis by targeting the PI3K/Akt signal pathway.

Podocyte injury is a major biomarker of primary glomerular disease, which leads to massive proteinuria and kidney failure. The increased production of the chemokine, fractalkine (FKN, CX3CL1), is a hallmark of multiple inflammatory diseases. However, the underlying mechanism of FKN in podocyte injury remains unknown. In this study, we performed an LPS infusion model in FKN knockout (FKN-/-, FKN-KO) mice. In cultured podocytes, we used plasmids to knockdown FKN and treated the podocytes with PI3K/Akt inhibitor (LY294002). Haematoxylin and eosin (HE) staining, Western Bolt, Co-immunoprecipitation (Co-IP), Immunofluorescence staining and flow cytometric analysis were employed to establish the role of FKN in podocyte injury. LPS stimulation resulted in kidney damage, increased the expression of the Bcl-2 family apoptosis protein, and decreased podocyte marker protein (nephrin, podocin and WT1) abundance compared with the WT mice. LPS-induced FKN-KO mice exhibited reduced lethality and inflammatory cell infiltration, podocyte apoptosis, and PI3K/Akt signal pathway inhibition compared to WT mice. In cultured podocytes, the interaction between FKN and the PI3K/Akt signalling pathway was well confirmed. FKN knockdown reduced podocyte apoptosis by regulating the Bcl-2 family; however, this protective effect was reversed by the co-administration of a PI3K/Akt inhibitor (LY294002). Overall, these findings reveal a novel mechanistic property of FKN, PI3K/Akt signalling, and podocyte apoptosis.

Fetal heart rate variability is a biomarker of rapid but not progressive exacerbation of inflammation in preterm fetal sheep

Perinatal infection/inflammation can trigger preterm birth and contribute to neurodevelopmental disability. There are currently no sensitive, specific methods to identify perinatal infection. We investigated the utility of time, frequency and non-linear measures of fetal heart rate (FHR) variability (FHRV) to identify either progressive or more rapid inflammation. Chronically instrumented preterm fetal sheep were randomly assigned to one of three different 5d continuous i.v. infusions: 1) control (saline infusions; n = 10), 2) progressive lipopolysaccharide (LPS; 200 ng/kg over 24 h, doubled every 24 h for 5d, n = 8), or 3) acute-on-chronic LPS (100 ng/kg over 24 h then 250 ng/kg/24 h for 4d plus 1 μg boluses at 48, 72, and 96 h, n = 9). Both LPS protocols triggered transient increases in multiple measures of FHRV at the onset of infusions. No FHRV or physiological changes occurred from 12 h after starting progressive LPS infusions. LPS boluses during the acute-on-chronic protocol triggered transient hypotension, tachycardia and an initial increase in multiple time and frequency domain measures of FHRV, with an asymmetric FHR pattern of predominant decelerations. Following resolution of hypotension after the second and third LPS boluses, all frequencies of FHRV became suppressed. These data suggest that FHRV may be a useful biomarker of rapid but not progressive preterm infection/inflammation.

Effects of Fluid Therapy on Mesenteric Microcirculation Using New Probe-Based Confocal Laser Endomicroscopy (Cellvizio®) in a Porcine Model of Endotoxic Shock

Background: Microcirculatory alterations have been observed at the early phase of sepsis, although macrocirculation seems preserved. The aim of this study was to analyze the effect of crystalloid fluid therapy on mesenteric microcirculation, assessed by using the confocal laser endomicroscope Cellvizio®, in an endotoxic porcine model. Methods: It is a prospective endotoxic shock (lipopolysaccharide infusion) experimental trial. Piglets were divided into 3 groups: 6 in the sham group (no LPS injection, no fluid), 9 in the control group (LPS infusion, no fluid), and 6 in the crystalloids group (LPS infusion and fluid resuscitation with crystalloids). Fluid resuscitation consisted in a fluid bolus of 20 mL/kg 0.9% saline over 30 min followed by a 10 mL/kg/h fluid rate over 4 h. Mesenteric microcirculation was assessed using a confocal laser endomicroscope (Cellvizio®). Blood flow within capillaries was visually assessed according to the point of care microcirculation (POEM) score. Results: At baseline, the 3 groups were similar regarding hemodynamic, biological, and microcirculatory parameters. At T360, the POEM score significantly decreased in the control and crystalloids groups, whereas it remained unchanged in the sham group (respectively, 1.62 ± 1.06, 1.2 ± 0.45, and 5.0 ± 0, p = 0.011). There was no significant difference in cardiac output at T360 between the sham and crystalloids groups (3.1 ± 0.8 vs. 2.3 ± 0.6, p = 0.132) or between the control and crystalloids groups (2.0 ± 0.6 vs. 2.3 ± 0.6, p = 0.90). Conclusion: There was no significant improvement of microcirculatory alterations after crystalloids resuscitation despite improvement in macrocirculatory parameters in early experimental sepsis.

Microcirculatory Function during Endotoxemia-A Functional Citrulline-Arginine-NO Pathway and NOS3 Complex Is Essential to Maintain the Microcirculation.

Competition for the amino acid arginine by endothelial nitric-oxide synthase (NOS3) and (pro-)inflammatory NO-synthase (NOS2) during endotoxemia appears essential in the derangement of the microcirculatory flow. This study investigated the role of NOS2 and NOS3 combined with/without citrulline supplementation on the NO-production and microcirculation during endotoxemia. Wildtype (C57BL6/N background; control; n = 36), Nos2-deficient, (n = 40), Nos3-deficient (n = 39) and Nos2/Nos3-deficient mice (n = 42) received a continuous intravenous LPS infusion alone (200 μg total, 18 h) or combined with L-citrulline (37.5 mg, last 6 h). The intestinal microcirculatory flow was measured by side-stream dark field (SDF)-imaging. The jejunal intracellular NO production was quantified by in vivo NO-spin trapping combined with electron spin-resonance (ESR) spectrometry. Amino-acid concentrations were measured by high-performance liquid chromatography (HPLC). LPS infusion decreased plasma arginine concentration in control and Nos3−/− compared to Nos2−/− mice. Jejunal NO production and the microcirculation were significantly decreased in control and Nos2−/− mice after LPS infusion. No beneficial effects of L-citrulline supplementation on microcirculatory flow were found in Nos3−/− or Nos2−/−/Nos3−/− mice. This study confirms that L-citrulline supplementation enhances de novo arginine synthesis and NO production in mice during endotoxemia with a functional NOS3-enzyme (control and Nos2−/− mice), as this beneficial effect was absent in Nos3−/− or Nos2−/−/Nos3−/− mice.

Protective role of scutellarin on LPS induced - Acute lung injury and regulation of apoptosis, oxidative stress and reduction of mitochondrial dysfunction.

Lung fluid accumulation was determined using wet/dry lung mass ratio. Rats subjected to LPS-induced acute lung injury (2.8 ± 0.33, P < 0.05) presented with a significantly higher wet to dry lung weight ration ratio than sham rats (1.6 ± 0.23, P < 0.05). These results demonstrate that acutely inured rats' lungs were oedematous. On the other hand, treatment with scutellarin alone and in combination with a JNK inhibitor, SP600125, both significantly attenuated pulmonary edema as shown via reduced wet/dry lung mass ratios (1.7 ± 0.09 and 1.8 ± 0.23; P < 0.05, respectively). These results showed that the interventions were effective against LPS-induced edema of the lungs. However, the difference between treatment groups' weight ratios was not statistically significant (P > 0.05). In the sham control rats, the levels of ROS and SOD production were maintained at a low and at a high concentration, respectively (P < 0.05). However, following LPS infusion, the ROS levels skyrocketed while that of SOD decreased significantly relative to the control rats (P < 0.05). Furthermore, we noted that pre-treatment with scutellarin reduced the ROS levels in LPS-injured rats while the SOD was increased to near control levels (P < 0.05). Moreover, the combined effect of scutellarin and JNK inhibitor SP600125 on the levels of ROS and the SOD activity followed a similar trend to that of scutellarin alone albeit with a lower magnitude of change. Our results also showed that the combinatorial treatment was not significantly different from scutellarin alone in terms of influence on the levels of ROS production and SOD activity (P > 0.05). The effect of Scutellarin on broncho-alveolar lavage fluid (BALF) cytokine secretion The expression of interleukins-1β, −18 and −6 in the broncho-alveolar lavage fluid were significantly upregulated by LPS infusion (P < 0.05). The rise was, however, attenuated via pre-treatment with scutellarin only or in conjunction with SP600125, a JNK inhibitor (all P < 0.05). On the contrary, we observed that LPS injection caused a reduction of interlekins −4 and −10 secreted in the BALF. Pre-treatment with scutellarin alone (P < 0.05) and not in combination with SP600125 or SP600125 was able to significantly reverse this noted down-regulation (all P > 0.05).

Protective role of cortistatin in pulmonary inflammation and fibrosis.

Acute lung injury (ALI), acute respiratory distress syndrome (ARDS) and pulmonary fibrosis remain major causes of morbidity, mortality and a healthcare burden in critically ill patient. There is an urgent need to identify factors causing susceptibility and for the design of new therapeutic agents. Here, we evaluate the effectiveness of the immunomodulatory neuropeptide cortistatin to regulate pulmonary inflammation and fibrosis in vivo. ALI/ARDS and pulmonary fibrosis were induced experimentally in wild-type and cortistatin-deficient mice by pulmonary infusion of the bacterial endotoxin LPS or the chemotherapeutic drug bleomycin, and the histopathological signs, pulmonary leukocyte infiltration and cytokines, and fibrotic markers were evaluated. Partially deficient mice in cortistatin showed exacerbated pulmonary damage, pulmonary inflammation, alveolar oedema and fibrosis, and subsequent increased respiratory failure and mortality when challenged to LPS or bleomycin, even at low doses. Treatment with cortistatin reversed these aggravated phenotypes and protected from progression to severe ARDS and fibrosis, after high exposure to both injury agents. Moreover, cortistatin-deficient pulmonary macrophages and fibroblasts showed exaggerated ex vivo inflammatory and fibrotic responses, and treatment with cortistatin impaired their activation. Finally, the protective effects of cortistatin in ALI and pulmonary fibrosis were partially inhibited by specific antagonists for somatostatin and ghrelin receptors. We identified cortistatin as an endogenous inhibitor of pulmonary inflammation and fibrosis. Deficiency in cortistatin could be a marker of poor prognosis in inflammatory/fibrotic pulmonary disorders. Cortistatin-based therapies could emerge as attractive candidates to treat severe ALI/ARDS, including SARS-CoV-2-associated ARDS.

Does chronic dietary exposure to the mycotoxin deoxynivalenol affect the porcine hepatic transcriptome when an acute-phase response is initiated through first or second-pass LPS challenge of the liver?

The sensitivity of pigs to deoxynivalenol (DON) might be increased by systemic inflammation (SI), which also has consequences for hepatic integrity. Liver lesions and a dys-regulated gene network might hamper hepatic handling and elimination of DON whereby the way of initiation of hepatic inflammation might play an additional role. First and second-pass exposure of the liver with LPS for triggering a SI was achieved by LPS infusion via pre- or post-hepatic venous route, respectively. Each infusion group was pre-conditioned either with a control diet (0.12 mg DON/kg diet) or with a DON-contaminated diet (4.59 mg DON/kg diet) for 4 wk. Liver transcriptome was evaluated at 195 min after starting infusions. DON exposure alone failed to modulate the mRNA expression significantly. However, pre- and post-hepatic LPS challenges prompted transcriptional responses in immune and metabolic levels. The mRNAs for B-cell lymphoma 2-like protein 11 as a key factor in apoptosis and IFN-γ released by T cells were clearly up-regulated in DON-fed group infused with LPS post-hepatically. On the other hand, mRNAs for nucleotide binding oligomerization domain containing 2, IFN-α and eukaryotic translation initiation factor 2α kinase 3 as ribosomal stress sensors were exclusively up-regulated in control pigs with pre-hepatic LPS infusion. These diverse effects were traced back to differences in TLR4 signalling.