Glucose and lipopolysaccharide differentially regulate fibroblast growth factor 21 in healthy male human volunteers - A prospective cross-over trial.

Fibroblast growth factor 21 (FGF21) affects the regulation of metabolism. Additionally, anti-inflammatory properties are attributed to FGF21, and studies in animals and humans show conflicting results. This study aimed to investigate how FGF21 is affected by glucose and lipopolysaccharide (LPS) in humans. Therefore, FGF21 was measured eight times at different time points within 48 h in this prospective cross-over trial after glucose and LPS on two different study days. The study included ten healthy, non-smoking male subjects aged 18-40. Repeated measures analysis of variance and paired t-test as post hoc analysis were applied. The administration of glucose and LPS resulted in a significant difference in regulating FGF21 (p < 0.001). After glucose administration, FGF21 declined sharply at 360 min, with a subsequent steep increase that exceeded baseline levels. LPS induced a drop in FGF21 after 180 min, while the baseline concentrations were not reached. After 180 min and 24 h, a statistically significant difference was demonstrated after adjusting the Bonferroni-Holm method. So, our results support the hypothesis that glucose and LPS differentially affect the human expression of FGF21 over 48 h.

Intravenous administration of LPS activates the kynurenine pathway in healthy male human subjects: a prospective placebo-controlled cross-over trial.

BACKGROUND: Administration of lipopolysaccharide (LPS) from Gram-negative bacteria, also known as the human endotoxemia model, is a standardized and safe model of human inflammation. Experimental studies have revealed that peripheral administration of LPS leads to induction of the kynurenine pathway followed by depressive-like behavior and cognitive dysfunction in animals. The aim of the present study is to investigate how acute intravenous LPS administration affects the kynurenine pathway in healthy male human subjects. METHODS: The present study is a prospective, single-blinded, randomized, placebo-controlled cross-over study to investigate the effects of intravenously administered LPS (Escherichia coli O113, 2 ng/kg) on tryptophan and kynurenine metabolites over 48 h and their association with interleukin-6 (IL-6) and C-reactive protein (CRP). The study included 10 healthy, non-smoking men (18-40 years) free from medication. Statistical differences in tryptophan and kynurenine metabolites as well as associations with IL-6 and CRP in LPS and placebo treated subjects were assessed with linear mixed-effects models. RESULTS: Systemic injection of LPS was associated with significantly lower concentrations of plasma tryptophan and kynurenine after 4 h, as well as higher concentrations of quinolinic acid (QUIN) after 48 h compared to the placebo injection. No differences were found in kynurenic acid (KYNA) or picolinic acid plasma concentrations between LPS or placebo treatment. The KYNA/kynurenine ratio peaked at 6 h post LPS injection while QUIN/kynurenine maintained significantly higher from 3 h post LPS injection until 24 h. The kynurenine/tryptophan ratio was higher at 24 h and 48 h post LPS treatment. Finally, we report an association between the kynurenine/tryptophan ratio and CRP. CONCLUSIONS: Our findings strongly support the concept that an inflammatory challenge with LPS induces the kynurenine pathway in humans, activating both the neurotoxic (QUIN) and neuroprotective (KYNA) branch of the kynurenine pathway. TRIAL REGISTRATION: This study is based on a study registered at ClinicalTrials.gov, NCT03392701 . Registered 21 December 2017.

Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Is Not Induced in Artificial Human Inflammation and Is Not Correlated with Inflammatory Response.

Lipoproteins, as well as proprotein convertase subtilisin/kexin type 9 (PCSK9), have been shown to play a key role in the innate immune response. However, knowledge about the role and kinetics of PCSK9 in human inflammation is currently insufficient. This study aimed to investigate the interaction between inflammation and lipid metabolism, including the possible role of PCSK9. A single-blinded, placebo-controlled cross-over study using the human endotoxin model was performed. Ten healthy men received lipopolysaccharide (LPS) or placebo on two different study days after overnight fasting. Lipoproteins as well as PCSK9 were measured repetitively over 48 h. PCSK9 plasma concentrations were not induced by LPS infusion, and no correlation between PCSK9 plasma concentrations and the degree of inflammation could be identified. The observed low-density lipoprotein (LDL) response to inflammation was more complex than anticipated, especially in the very early phase after the inflammatory stimulus. Baseline concentrations of LDL, as well as high-density lipoprotein (HDL), correlated negatively with inflammatory response. Our data suggest that the lipoprotein response to inflammation is independent of PCSK9. The proposed elevations of PCSK9 and suspected correlations between PCSK9 levels and inflammatory response are not supported by our data. (This study has been registered at ClinicalTrials.gov under registration no. NCT03392701.).

SUBCLINICAL KIDNEY INJURY IS CAUSED BY A MODERATE SINGLE INFLAMMATORY EVENT.

ABSTRACT: Background: Current means of diagnosis of acute kidney injury (AKI) based on serum creatinine have poor sensitivity and may miss possible therapeutic windows in subclinical kidney injury, especially in septic AKI. Kidney injury molecule-1 (KIM-1) may be a valuable biomarker to improve diagnostic algorithms for AKI. The understanding of septic AKI is still insufficient, and knowledge about KIM-1 kinetics in inflammation is scarce. The aim of this study was to investigate the possible effect of lipopolysaccharide (LPS) on KIM-1 as a marker of structural kidney injury in healthy volunteers. Methods: A single-blinded, placebo-controlled cross-over study using the human endotoxin model (LPS administration) was performed in 10 healthy men. Kidney injury molecule-1 and serum creatinine were measured repetitively for 48 hours. Results: We observed a significant elevation of serum KIM-1 levels after the administration of LPS ( P < 0.001). Furthermore, LPS caused a significant elevation of serum creatinine at an early time point ( P = 0.013) as compared with placebo. Conclusion: Even a relatively small inflammatory stimulus is sufficient to cause subclinical structural kidney injury with elevated KIM-1 and serum creatinine in healthy volunteers. This outlines the insufficiency of the current diagnostic approach regarding AKI and the urgency to develop novel diagnostic algorithms including markers of kidney injury. Clinical Trial Registration:www.clinicaltrials.gov . Unique identifier: NCT03392701 (August 1, 2018).

High Anti-CoV2S Antibody Levels at Hospitalization Are Associated with Improved Survival in Patients with COVID-19 Vaccine Breakthrough Infection.

BACKGROUND: Although vaccination against COVID-19 is highly effective, breakthrough infections occur, often leading to severe courses and death. The extent of protection provided by individual antibody levels in breakthrough infections is still unknown and cut-off levels have yet to be determined. METHODS: In 80 consecutive fully vaccinated patients hospitalized between August and December 2021 with COVID-19 breakthrough infection (Delta variant), anti-CoV2S antibody levels were analyzed for the endpoint of death. RESULTS: Ten out of the 12 patients who died (83.3%) had antibody levels < 600 U/mL; 5 (41.7%) of these had antibody levels < 200 U/mL. Only 2 patients with a level of >600 U/mL died from vaccine breakthrough infection. Correction for the number of comorbidities and age revealed that anti-CoV2S antibody levels at the time of hospitalization were a significant predictor for reduced risk of death (OR = 0.402 for every 1000 U/mL, p = 0.018). CONCLUSIONS: In this retrospective data analysis, we show that almost all patients who died from COVID-19 vaccine breakthrough infection had antibody levels < 600 U/mL, most of them below 200 U/mL. In logistic regression corrected for the number of comorbidities and age, anti-CoV2S antibody levels at the time of hospitalization proved to be a significantly protective predictor against death.

Effect of repeated bolus and continuous glucose infusion on a panel of circulating biomarkers in healthy volunteers.

HYPOTHESIS: Glycaemic variability (GV) refers to fluctuations in the blood glucose level and may contribute to complications in patients suffering from Diabetes. Several studies show negative effects of GV on the cardiovascular system, however there is still a lack of conclusive evidence. Using an explorative cardiovascular panel, it is possible to simultaneously measure the effects on proteins relevant for cardiovascular processes. The aim of this study was to investigate the effects of rapid glucose excursions on cardiovascular and metabolic parameters in healthy individuals. METHODS: An explorative single-blinded cross-over study was performed in ten healthy men. Subjects received 3 times 20 grams of glucose i.v. over 5 minutes or 60 grams of glucose continuously over 3 hours. Blood was taken for repeated measurements of the cardiovascular panel over the following 6 hours and again after 24 and 48 hours. RESULTS: We observed a significant elevation of 7 cardiovascular biomarkers (BMP6, SLAMF7, LOX-1, ADAMTS13, IL-1RA, IL-4RA, PTX3) at t = 360min after rapid glucose infusion compared to a continuous glucose infusion. CONCLUSIONS: Intraday GV seems to have acute effects on cardiovascular proteins in healthy test persons. Rapid glucose administration compared to continuous administration showed significant changes in BMP6, SLAMF7, ADAMTS13, IL1RA, PTX3, IL-4RA and LOX-1. CLINICAL TRIAL REGISTRATION: NCT04488848.

Storm of Cardiovascular Markers After LPS Administration in Human Volunteers.

Acute infections are associated with an elevated cardiovascular risk. However, little is known about the interactions of acute inflammatory responses and the cardiovascular system. We therefore aimed to evaluate effects of acute inflammatory stimuli mediated by LPS administration on a set of 89 cardiovascular biomarkers. A single-blinded, placebo-controlled cross-over study using the human endotoxin model was performed. Ten healthy men were administered lipopolysaccharide (LPS) or placebo on two different study days after an overnight fast. Eighty-nine different cardiovascular biomarkers were measured repetitively over 48 h. Out of 89 cardiovascular biomarkers, 54 markers were significantly influenced by LPS infusion. The observed biomarker response to inflammation was more pronounced and complex than anticipated. In conclusion, our data show that the cardiovascular system is under enormous distress in response to experimental low-dose inflammation in humans, as demonstrated by a significant effect on 54 of the 89 biomarkers tested.

Correction to: Intrahospital mortality of influenza patients during the 2017-2018 influenza season : Report from a tertiary care hospital in Austria.

Correction to: Wien Klin Wochenschr 2019 https://doi.org/10.1007/s00508-019-01578-9 The original version of this article unfortunately contained a mistake in the title. The correct title is: Intrahospital mortality of influenza patients.The original article has been corrected. We apologize for the ….

Intrahospital mortality of influenza patients during the 2017-2018 influenza season : Report from a tertiary care hospital in Austria.

BACKGROUND: Seasonal influenza is responsible for excess mortality and morbidity all over the northern hemisphere. To the authors' knowledge there are no comprehensive data available about morbidity and mortality of hospitalized influenza patients in Austria. The aim of this study was to assess the intrahospital mortality of hospitalized patients with influenza in this tertiary care hospital. METHODS: During the 2017-2018 influenza season all patients presenting to the emergency department with influenza-like illness as well as hospitalized patients developing symptoms suggestive of influenza were tested with a rapid real-time PCR influenza test. In total 751 patients were tested at this tertiary care hospital and 330 showed a positive Influenza test result positive and were therefore included in the present study. The primary outcome was intrahospital mortality. RESULTS: Of the 330 positively tested patients n = 110 (33%) were type A influenza and n = 220 (67%) were type B influenza. The hospitalization rate of patients presenting to the emergency department with a positive influenza test was 59% with a mean length stay of 8.6 days in this hospital and an intrahospital mortality of 8.3% (n = 16). Pneumonia was diagnosed in 30% of hospitalized patients with influenza and antibiotics were used in 65.8% of all hospitalized patients with influenza. Patients aged 80 years and older reached an intrahospital mortality of 16.4%. CONCLUSION: The results of the present study show a high hospitalization and intrahospital mortality rate of influenza patients in a tertiary care hospital during the 2017-2018 influenza season in Austria.