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.).

Comparison between activated clotting time and anti-activated factor X activity for the monitoring of unfractionated heparin therapy in patients with aortic aneurysm undergoing an endovascular procedure.

OBJECTIVE: Current guidelines recommend administration of unfractionated heparin (UFH) and measurement of activated clotting time (ACT) during endovascular procedures. The aim of this study was to compare ACT and anti-activated factor X (anti-Xa) measurements for monitoring of UFH therapy during an aortic endograft procedure and to assess the association of peak ACT and peak anti-Xa activity with periprocedural bleeding. METHODS: We retrospectively studied 104 patients with aortic aneurysm undergoing endovascular procedures with repeated coagulation measurements. After a UFH bolus, further UFH doses were given according to ACT (target range, ≥250 seconds) in clinical routine, and in parallel to each ACT (Hemochron; Accriva Diagnostics, Newport Beach, Calif) measurement, we determined anti-Xa activity (HemosIL Liquid anti-Xa; Instrumentation Laboratory, Bedford, Mass). UFH redosing was solely based on the ACT measurements. We defined periprocedural bleeding as a drop in hemoglobin level ≥3 g/dL or red blood cell transfusion within 24 hours. RESULTS: After the initial UFH bolus (median, 67 IU/kg body weight), ACT and anti-Xa measurements showed a weak correlation (rs, 0.46; P < .001). Median ACT was 233 seconds (range, 127-374 seconds; interquartile range [IQR], 204-257 seconds); median anti-Xa activity was 1.0 IU/mL (range, 0.5-2.0 IU/mL; IQR, 0.9-1.2 IU/mL). Only 31% of the patients had an ACT value ≥250 seconds, whereas all patients had an anti-Xa activity ≥0.5 IU/mL. Accordingly, ACT triggered redosing of UFH frequently. Consequently, we saw a median total UFH use of 90 IU/kg during the procedure, a median peak ACT of 255 seconds (IQR, 234-273 seconds), and a median peak anti-Xa activity of 1.2 IU/mL (IQR, 1.0-1.4 IU/mL). Periprocedural bleeding occurred in 40 (38%) patients. Peak ACT ≥250 seconds was not associated with bleeding (odds ratio, 1.05; 95% confidence interval, 0.41-2.70; P = .952), whereas peak anti-Xa activity ≥1.2 IU/mL was independently associated with bleeding (odds ratio, 4.95; 95% confidence interval, 1.82-13.48; P = .002). Moreover, no periprocedural thromboembolic event occurred. CONCLUSIONS: In this retrospective study of patients with aortic aneurysm undergoing an endovascular procedure, ACT and anti-Xa measurements showed poor correlation; only increased peak anti-Xa activity was independently associated with periprocedural bleeding, not increased ACT. Our findings also suggest that monitoring of UFH therapy with anti-Xa during aortic endograft procedures may reduce total UFH use. We further speculate that this approach could reduce periprocedural bleeding.

Prognostic Value of Inflammatory and Cardiovascular Biomarkers for Prediction of 90-Day All-Cause Mortality after Acute Ischemic Stroke-Results from the Linz Stroke Unit Study.

BACKGROUND: Early outcome prediction after acute ischemic stroke is of great interest. The aim of our study was to evaluate the prognostic value of blood biomarkers in patients with acute ischemic stroke. METHODS: We measured interleukin-6 (IL-6), d-dimer, amino-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin T, and soluble ST2 plasma concentrations within 24 h after admission to our stroke unit in 721 consecutive acute ischemic stroke patients. End point was 90-day all-cause mortality. RESULTS: During follow-up 81 patients died (11%). In univariate Cox proportional hazards regression analyses with the biochemical markers dichotomized according to median values, all baseline blood biomarkers were strong prognostic markers. However, in the multivariate analysis after adjustment for several clinical variables and the NIH Stroke Scale (NIHSS), only NIHSS >3 [risk ratio (RR) 7.87, 95% CI, 3.61-17.16; P < 0.001], IL-6 > 7 pg/mL (RR 4.09, 95% CI, 2.02-8.29; P < 0.001), and NT-proBNP >447 ng/L (RR 4.88, 95% CI, 2.41-9.88; P < 0.001) remained independent predictors. Using a simple multimarker approach combining these 3 complementary markers, we demonstrated that patients with increased NIHSS, IL-6, and NT-proBNP had the poorest outcome with a mortality rate of 38%, whereas no patient with negative readings for all 3 markers died during follow-up. CONCLUSIONS: In this large cohort of patients with acute ischemic stroke, IL-6 and NT-proBNP at admission were strong and independent prognostic markers for 90-day all-cause mortality, and provided complementary prognostic information to the routinely used stroke severity score NIHSS.

Concentrated lyophilized plasma used for reconstitution of whole blood leads to higher coagulation factor activity but unchanged thrombin potential compared with fresh-frozen plasma.

BACKGROUND: During massive hemorrhage, it is recommended to transfuse red blood cells, platelet concentrate, and fresh-frozen plasma in a ratio close to 1:1:1. To avoid the thawing process of fresh frozen plasma, lyophilized plasma (LP) is increasingly used. Evidence is limited on the activity of coagulation factors in reconstituted blood using LP and concentrated LP versions. STUDY DESIGN AND METHODS: Whole blood from ten healthy volunteers was separated into red blood cell, fresh frozen plasma, and platelet concentrate units. Aliquots of red blood cells and plasma concentrate were mixed with either fresh frozen plasma (200 mL) or LP at reconstitution ratios of 2:1:1, 1:1:1, and 1:1:2. LP was used either at the recommended standard volume of 200 mL (LP200) or was more concentrated at volumes of 100 and 50 mL (LP100 and LP50, respectively). The hemostatic capacity of each reconstituted whole blood sample was tested with blood cell counts, standard coagulation tests, factor activity, thrombin generation, and viscoelastic assays. RESULTS: Hematocrit, platelet counts, and fibrinogen levels of the three ratios were similar between FFP200 and LP200 units but were lower compared with the corresponding ratios in LP100 and LP50 units. The activity of procoagulant and anticoagulant factors increased linearly with the increasing plasmatic fraction and, at 1:1:2 ratio, was significantly higher in LP50 units compared with FFP200 and LP200 units. Thrombin generation was similar throughout the four plasma groups at any ratio. CONCLUSIONS: Decreasing the dilution volume of LP facilitates reaching higher hematocrit and coagulation protein levels without a relevant increase in thrombin generation. This is due to preserved balance between procoagulant and anticoagulant factors in the concentrated LP preparations.

Increased soluble ST2 predicts long-term mortality in patients with stable coronary artery disease: results from the Ludwigshafen risk and cardiovascular health study.

BACKGROUND: Soluble suppression of tumorigenicity 2 (sST2) has emerged as a strong prognostic biomarker in patients with heart failure and myocardial infarction. The aim of this study was to evaluate the long-term prognostic value of sST2 in patients with stable coronary artery disease (CAD). METHODS: sST2 plasma concentrations were measured in 1345 patients with stable CAD referred for coronary angiography at a single tertiary care center. The primary endpoint was all-cause mortality. RESULTS: During a median follow-up time of 9.8 years, 477 (36%) patients died. The median sST2 plasma concentration at baseline was significantly higher among decedents than survivors (21.4 vs 18.5 ng/mL; P < 0.001). In multivariate Cox proportional hazards regression analysis, sST2 was an independent predictor of all-cause mortality (risk ratio 1.16 per 1-SD increase in log-transformed values; 95% CI 1.05-1.29; P = 0.004). In the same multivariate analysis, amino-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) were also independent predictors, whereas galectin-3 was not. Patients with sST2 in the highest quartile (>24.6 ng/mL) displayed a 2-fold increased risk of death in univariate analysis, which was attenuated but remained significant in a fully adjusted model (risk ratio 1.39; 95% CI 1.10-1.76; P = 0.006). Further analysis showed that the prognostic impact of sST2 was additive to NT-proBNP and hs-cTnT. Using a multibiomarker approach combining these 3 complementary makers, we demonstrated that patients with all 3 biomarkers in the highest quartiles had the poorest outcome. CONCLUSIONS: In this cohort of patients with stable CAD, increased sST2 was an independent predictor of long-term all-cause mortality and provided complementary prognostic information to hs-cTnT and NT-proBNP.

Immunogenicity Parameters of Cancer Patients Receiving the mRNA Vaccine BNT162b2 While Obtaining Radiotherapy: A Longitudinal Cohort Evaluation.

BACKGROUND: Cancer patients are highly prone to infectious diseases. While undergoing antineoplastic treatment, the risk of severe symptoms upon infection increases, necessitating efficient protective measures, such as vaccination. For patients receiving radiotherapy, there is no specific information about humoral immunity. During the COVID-19 pandemic, serial antibody measurements were therefore offered to cancer patients, following SARS-CoV-2 vaccination while obtaining radiotherapy. METHODS: Out of 74 enrolled patients, 46 met the inclusion criteria. Two cohorts were allocated, depending on an association with chemotherapy or pure radiotherapy. An additional healthy control cohort of 16 healthcare workers was enrolled. All participants followed a two-fold BNT162b2 vaccine schedule. SARS-CoV-2 binding antibodies were measured serially in a 7-day cycle for 35 days and over the long-term, using the Elecsys® Anti-SARS-CoV-2 immunoassay. RESULTS: Cancer patients under pure radiotherapy have a comparable humoral vaccination response and long-term persistency of antibodies to healthy controls. Patients receiving additional chemotherapy show a significantly delayed immune response and decreased antibody titers. The vaccine was well tolerated in all cohorts. CONCLUSIONS: Pure radiotherapy in cancer patients does not interfere with the vaccine-induced humoral immune response or other immunogenetic aspects, whereas previous or simultaneous chemotherapy does. Findings are of particular relevance for future epidemic or pandemic scenarios.

SARS-CoV-2 vaccination willingness and humoral vaccination response in radiation oncology patients.

BACKGROUND: SARS-CoV-2 infection has been and, in some parts, still is a threat to oncologic patients, making it crucial to understand perception of vaccination and immunologic responses in this vulnerable patient segment. SARS-CoV-2 vaccines in relation to malignant disease characteristics and therapies have so far not been studied consecutively in larger oncologic patient populations. This study captures SARS-CoV-2 vaccination willingness and humoral immune response in a large consecutive oncologic patient collective at the beginning of 2021. METHODS: 1142 patients were consecutively recruited over 5.5 months at a tertiary department for radiation oncology and were assessed for vaccination willingness via a standardized interview. In already vaccinated patients total SARS-CoV-2 S antibody titres against the spike protein (Anti-SARS-CoV-2 S) and were evaluated 35 days or later after the first dose of SARS-CoV-2 vaccine. RESULTS: Vaccination willingness was high with a rate of 90 %. The most frequent reasons for rejection were: undecided/potential vaccination after therapy, distrust in the vaccine and fear of interaction with comorbidities. Factors associated with lower vaccination willingness were: worse general condition, lower age and female sex. 80 % of the participants had been previously vaccinated, 8 % reported previous infection and 16 % received vaccination during antineoplastic therapy. In 97.5 % of the vaccinated patients Anti-SARS-CoV-2 S was detected. In a univariable analysis parameters associated with non-conversion were: lower performance status, spread to the local lymphatics (N + ), hematologic disease and diffuse metastases. All patients with oligometastatic disease achieved positive Anti-SARS-CoV-2 S titres. For patients with two vaccinations several risk factors were identified, that were associated with low antibody concentrations. CONCLUSIONS: SARS-CoV-2 vaccination willingness among oncologic patients was high in the first months after its availability, and most patients had already received one or two doses. Over 97 % of vaccinated patients had measurable anti-SARS-CoV-2 S titres. Our data supports early identification of low humoral responders after vaccination and could facilitate the design of future oncologic vaccine trials (clinicaltrials.gov Identifier: NCT04918888).

Coincidence of plasma cell leukemia and COVID-19: a diagnostic pitfall.

We report the case of a 66-year-old man with a known history of IgD multiple myeloma (MM) which was admitted to hospital because of acute renal failure. Routine PCR testing on admission yielded a positive result for SARS-CoV-2 infection. Examination of the peripheral blood (PB) smear revealed 17% lymphoplasmacytoid cells and a few small plasma cells mimicking morphological changes frequently seen in viral diseases. However, flow cytometric examination showed 20% clonal lambda-restricted plasma cells being consistent with a diagnosis of secondary plasma cell leukemia. Circulating plasma cells as well as similar appearing lymphocyte subtypes such as plasmacytoid lymphocytes are frequently observed in infectious disorders such as COVID-19, so that the lymphocyte morphology in our patient's case could have been easily misinterpreted as typical COVID-19-induced changes. Our observation highlights the importance of incorporating clinical, morphological, and flow-cytometric data in distinguishing between reactive and neoplastic lymphocyte changes because misinterpretation may affect disease classification and, beyond that, clinical decision-making, which may have serious consequences for patients.

Coincidence of plasma cell leukemia and COVID-19: a diagnostic pitfall.

We report the case of a 66-year-old man with a known history of IgD multiple myeloma (MM) which was admitted to hospital because of acute renal failure. Routine PCR testing on admission yielded a positive result for SARS-CoV-2 infection. Examination of the peripheral blood (PB) smear revealed 17% lymphoplasmacytoid cells and a few small plasma cells mimicking morphological changes frequently seen in viral diseases. However, flow cytometric examination showed 20% clonal lambda-restricted plasma cells being consistent with a diagnosis of secondary plasma cell leukemia. Circulating plasma cells as well as similar appearing lymphocyte subtypes such as plasmacytoid lymphocytes are frequently observed in infectious disorders such as COVID-19, so that the lymphocyte morphology in our patient's case could have been easily misinterpreted as typical COVID-19-induced changes. Our observation highlights the importance of incorporating clinical, morphological, and flow-cytometric data in distinguishing between reactive and neoplastic lymphocyte changes because misinterpretation may affect disease classification and, beyond that, clinical decision-making, which may have serious consequences for patients.

The neuropeptide catestatin acts as a novel angiogenic cytokine via a basic fibroblast growth factor-dependent mechanism.

RATIONALE: The neuropeptide catestatin is an endogenous nicotinic cholinergic antagonist that acts as a pleiotropic hormone. OBJECTIVE: Catestatin shares several functions with angiogenic factors. We therefore reasoned that catestatin induces growth of new blood vessels. METHODS AND RESULTS: Catestatin induced migration, proliferation, and antiapoptosis in endothelial cells and exerted capillary tube formation in vitro in a Matrigel assay, and such effects were mediated via G protein, mitogen-activated protein kinase, and Akt. Catestatin-induced endothelial cell functions are further mediated by basic fibroblast growth factor, as shown by blockade of effects by a neutralizing fibroblast growth factor antibody. Furthermore, catestatin released basic fibroblast growth factor from endothelial cells and stimulated fibroblast growth factor signaling. In addition to its function on endothelial cells, catestatin also exerted effects on endothelial progenitor cells and vascular smooth muscle cells. In vivo, catestatin induced angiogenesis in the mouse cornea neovascularization assay and increased blood perfusion and number of capillaries in the hindlimb ischemia model. In addition to angiogenesis, catestatin increased density of arterioles/arteries and incorporation of endothelial progenitor cells in the hindlimb ischemia model, indicating induction of arteriogenesis and postnatal vasculogenesis. CONCLUSION: We conclude that catestatin acts as a novel angiogenic cytokine via a basic fibroblast growth factor-dependent mechanism.

Soluble suppression of tumorigenesis-2 is a strong predictor of all-cause, cardiovascular and infection-related mortality risk in haemodialysis patients with diabetes mellitus.

Background: Soluble suppression of tumorigenesis-2 (sST2) is a strong prognostic biomarker of cardiovascular (CV) disease. End-stage kidney disease (ESKD) patients are at high risk of CV events and infections. Herein we investigated the utility of sST2 to predict all-cause and cause-specific mortality in haemodialysis (HD) patients with diabetes mellitus. Methods: sST2 concentrations were measured in plasma samples of 1196 participants of the German Diabetes and Dialysis (4D) study who had type 2 diabetes mellitus and received maintenance HD for ESKD. Hazard ratios (HRs) for prespecified, adjudicated endpoints were determined according to sST2 levels at baseline by multivariate Cox proportional hazards analysis. Results: Participants (mean age 66 years, 54% male) had a median sST2 concentration of 25 ng/mL and were followed up for 4 years. After adjustment for possible confounders, participants with sST2 concentrations in the highest (>32.6 ng/mL) compared with the lowest (<20.1 ng/mL) quartile exhibited a 2-fold higher all-cause mortality risk {[HR 2.06 95% confidence interval (CI) 1.61-2.61]; P < .001}. High sST concentrations (fourth versus first quartile) were strongly associated with the risk of cardiac death [HR 2.29 (95% CI 1.55-3.39); P < .001]. Analysis of individual components of cardiac causes of death showed an increased risk of sudden death [HR 2.24 (95% CI 1.33-3.77); P < .001], death due to myocardial infarction [HR 2.12 (95% CI 0.9-5.0); P = .087] and heart failure [HR 3.34 (95% CI 1.15-9.75); P = .027] in participants with sST2 levels in the highest compared with the lowest quartile. Likewise, participants with the highest sST2 levels had an increased risk of fatal stroke [HR 1.92 (95% CI 1.17-3.14); P = .009] and fatal infections [HR 2.01 (95% CI 1.2-3.37); P = .008]. In contrast to fatal CV events, sST2 was not associated with the risk of non-fatal myocardial infarction [HR 0.68 (95% CI 0.41-1.12); P = .132] or non-fatal stroke [HR 1.28 (95% CI 0.64-2.53); P = .485]. Conclusions: In HD patients with diabetes mellitus, high concentrations of sST2 were strongly and independently associated with an increased risk of all-cause mortality, CV mortality and death due to infection but not non-fatal CV events.

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).