Lipopolysaccharide endotoxin injections elevated salivary TNFα and corneal temperatures and induced dynamic changes in circulating leukocytes, inflammatory cytokines, and metabolic indicators in wether lambs

Pathogenic infections increase morbidity and reduce performance in livestock, and thus understanding the comprehensive physiological changes associated with infections can benefit production sustainability. In this study, we sought to investigate such physiological responses to an acute immune challenge in lambs. Polypay wethers received single IV injections of 1.5 µg/kg lipopolysaccharide endotoxin (LPS-injected; n = 6) or saline (controls; n = 6). Corneal temperatures (via infrared thermography), rectal temperatures, blood, plasma, and saliva were assessed every 2 h for 10 h after injections. Blood was also assessed at 24 h. LPS-injected lambs exhibited elevated (P < 0.05) corneal and rectal temperatures that peaked at 4 h but were still slightly greater (P < 0.05) than controls at 10 h. Circulating total white blood cells, monocytes, and granulocytes were reduced (P < 0.05) in LPS-injected lambs within the first 4 h but were subsequently greater (P < 0.05) than in controls. Lymphocytes were reduced (P < 0.05) in LPS-injected lambs over the first 8 h and did not differ from controls thereafter. Red blood cells, hematocrit, and hemoglobin were increased (P < 0.05) in LPS-injected lambs over the first 6 h, indicating mild dehydration. Blood glucose briefly increased (P < 0.05) in LPS-injected lambs at 2 h but was less (P < 0.05) than in controls thereafter. Blood lactate was greater (P < 0.05) in LPS-injected lambs between 6 and 10 h after injections, which together with reduced (P < 0.05) CO2 partial pressure indicated a metabolic shift toward glycolysis. LPS-injected lambs exhibited a transient increase (P < 0.05) in plasma TNFα at 2 and 4 h only and sustained increases (P < 0.05) in CXCL9 and CXCL10 beginning at 6 and 4 h, respectively. They also exhibited a mild, paradoxical increase (P < 0.05) in the anti-inflammatory sFRP3. Salivary TNFα was increased (P < 0.05) in LPS-injected lambs at 2 h only. Regression analyses indicated that rectal temperatures were a generally poor predictor of the other inflammatory components in this study, with the exception of circulating leukocyte populations. Likewise, correlations among the 10 cytokines measured in this study were generally weak, with notable exceptions between CXCL9 and CXCL10 and between IL-21 and IFNγ. These findings demonstrate that physiological changes to even short-lived immune challenges are dynamic in nature and persist beyond the time frame of febrile responses and other common assessments.

Stressor-Dependant Changes in Immune Parameters in the Terrestrial Isopod Crustacean, Porcellio scaber: A Focus on Nanomaterials

We compared the changes of selected immune parameters of Porcellio scaber to different stressors. The animals were either fed for two weeks with Au nanoparticles (NPs), CeO2 NPs, or Au ions or body-injected with Au NPs, CeO2 NPs, or lipopolysaccharide endotoxin. Contrary to expectations, the feeding experiment showed that both NPs caused a significant increase in the total haemocyte count (THC). In contrast, the ion-positive control resulted in a significantly decreased THC. Additionally, changes in phenoloxidase (PO)-like activity, haemocyte viability, and nitric oxide (NO) levels seemed to depend on the stressor. Injection experiments also showed stressor-dependant changes in measured parameters, such as CeO2 NPs and lipopolysaccharide endotoxin (LPS), caused more significant responses than Au NPs. These results show that feeding and injection of NPs caused an immune response and that the response differed significantly, depending on the exposure route. We did not expect the response to ingested NPs, due to the low exposure concentrations (100 μg/g dry weight food) and a firm gut epithelia, along with a lack of phagocytosis in the digestive system, which would theoretically prevent NPs from crossing the biological barrier. It remains a challenge for future research to reveal what the physiological and ecological significance is for the organism to sense and respond, via the immune system, to ingested foreign material.

A New Look at the Enterobacterial Common Antigen Forms Obtained during Rough Lipopolysaccharides Purification

Enterobacterial common antigen (ECA) is a conserved antigen expressed by enterobacteria. It is built by trisaccharide repeating units: →3)-α-D-Fucp4NAc-(1→4)-β-D-ManpNAcA-(1→4)-α-D-GlcpNAc-(1→ and occurs in three forms: as surface-bound linear polysaccharides linked to a phosphoglyceride (ECAPG) or lipopolysaccharide − endotoxin (ECALPS), and cyclic form (ECACYC). ECA maintains, outer membrane integrity, immunogenicity, and viability of enterobacteria. A supernatant obtained after LPS ultracentrifugation was reported as a source for ECA isolation, but it has never been assessed for detailed composition besides ECACYC. We used mild acid hydrolysis and gel filtration, or zwitterionic-hydrophilic interaction liquid (ZIC®HILIC) chromatography combined with mass spectrometry for purification, fractionation, and structural analysis of rough Shigella sonnei and Escherichia coli R1 and K12 crude LPS preparations. Presented work is the first report concerning complex characteristic of all ECA forms present in LPS-derived supernatants. We demonstrated high heterogeneity of the supernatant-derived ECA that contaminate LPS purified by ultracentrifugation. Not only previously reported O-acetylated tetrameric, pentameric, and hexameric ECACYC have been identified, but also devoid of lipid moiety linear ECA built from 7 to 11 repeating units. Described results were common for all selected strains. The origin of linear ECA is discussed against the current knowledge about ECAPG and ECALPS.

Analysis of Endotoxin Adsorption in Two Swedish Patients with Septic Shock

Background: Lipopolysaccharide (endotoxin) from the outer Gram-negative bacterial wall can induce a harmful immunologic response, involving hemodynamic deprivation, and is one important motor driving the septic cascade. The positively charged poly-imine ethylene layer on the oXiris membrane is capable of adsorbing negatively charged endotoxin molecules and removing them from the blood compartment. Endotoxin is detrimental and should be removed from blood. Summary: The adsorbable endotoxin fraction in blood arises from a tight balance between seeding from an infectious focus and removal by an overwhelmed immune system. The net sum of remaining endotoxin in blood is available for an adsorption process in the oXiris filter. Endotoxin data from 2 patients with severe Gram-negative septic shock and endotoxemia in this case series, speaks for a considerable share of the adsorption of the oXiris filter in the endotoxin net removal over time. Key Messages: Analysis of combined in vitro and in vivo data speaks for an effect of the oXiris filter in lowering endotoxin.