Neurological outcomes one year after COVID-19 diagnosis: a prospective longitudinal cohort study

INTRODUCTION

Neurological sequelae from COVID-19 may persist after recovery from acute infection. Here, we aimed to describe the natural history of neurological manifestations over one year after COVID-19.

METHODS

We performed a prospective, multicentre, longitudinal cohort study in COVID-19 survivors. At 3-month and 1-year follow-up, patients were assessed for neurological impairments by a neurological examination and a standardized test battery including the assessment of hyposmia (16-item Sniffin-Sticks-test, SS-16), cognitive deficits (Montreal Cognitive Assessment<26), and mental health (Hospital Anxiety and Depression Scale, and Post-traumatic Stress Disorder Checklist-5).

RESULTS

Eighty-one patients were evaluated one year after COVID-19, out of which 76/81 (94%) patients completed 3-month and 1-year follow-up. Patients were 54 (47-64) years old and 59% were male. New and persistent neurological disorders were found in 15% (3-months) and 12% (10/81; 1-year). Symptoms at 1-year follow-up were reported by 48/81 (59%) patients, including fatigue (38%), concentration difficulties (25%), forgetfulness (25%), sleep disturbances (22%), myalgia (17%), limb weakness (17%), headache (16%), impaired sensation (16%), and hyposmia (15%). Neurological examination revealed findings in 52/81 (64%) patients without improvement over time (3-months: 61%, p=0.230) including hyposmia (SS-16<13; 51%). Cognitive deficits were apparent in 18%, whereas depression, anxiety, and post-traumatic stress disorders were diagnosed in 6%, 29%, and 10% one year after infection, respectively. These mental and cognitive disorders did not improve since 3-month follow-up (all p>0.05).

CONCLUSION

Our data indicate that a significant patient number still suffer from neurological sequelae including neuropsychiatric symptoms one year after COVID-19 calling for interdisciplinary management of these patients.

Upregulation of Checkpoint Ligand Programmed Death-Ligand 1 in Patients with Paroxysmal Nocturnal Hemoglobinuria Explained by Proximal Complement Activation

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hemolytic disease driven by impaired complement regulation. Mutations in genes encoding the enzymes that build the GPI anchors are causative, with somatic mutations in the PIG-A gene occurring most frequently. As a result, the important membrane-bound complement regulators CD55 and CD59 are missing on the affected hematopoietic stem cells and their progeny, rendering those cells vulnerable to complement attack. Immune escape mechanisms sparing affected PNH stem cells from removal are suspected in the PNH pathogenesis, but molecular mechanisms have not been elucidated. We hypothesized that exuberant complement activity in PNH results in enhanced immune checkpoint interactions, providing a molecular basis for the potential immune escape in PNH. In a series of PNH patients, we found increased expression levels of the checkpoint ligand programmed death-ligand 1 (PD-L1) on granulocytes and monocytes, as well as in the plasma of PNH patients. Mechanistically, we demonstrate that complement activation leading to the decoration of particles/cells with C3- and/or C4-opsonins increased PD-L1 expression on neutrophils and monocytes as shown for different in vitro models of classical or alternative pathway activation. We further establish in vitro that complement inhibition at the level of C3, but not C5, inhibits the alternative pathway-mediated upregulation of PD-L1 and show by means of soluble PD-L1 that this observation translates into the clinical situation when PNH patients are treated with either C3 or C5 inhibitors. Together, the presented data show that the checkpoint ligand PD-L1 is increased in PNH patients, which correlates with proximal complement activation.

SARS-CoV-2 Beta variant infection elicits potent lineage-specific and cross-reactive antibodies

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Beta variant of concern (VOC) resists neutralization by major classes of antibodies from COVID-19 patients and vaccinated individuals. In this study, serum of Beta-infected patients revealed reduced cross-neutralization of wild-type virus. From these patients, we isolated Beta-specific and cross-reactive receptor-binding domain (RBD) antibodies. The Beta-specificity results from recruitment of VOC-specific clonotypes and accommodation of mutations present in Beta and Omicron into a major antibody class that is normally sensitive to these mutations. The Beta-elicited cross-reactive antibodies share genetic and structural features with wild type-elicited antibodies, including a public VH1-58 clonotype that targets the RBD ridge. These findings advance our understanding of the antibody response to SARS-CoV-2 shaped by antigenic drift, with implications for design of next-generation vaccines and therapeutics.

Investigating phenotypes of pulmonary COVID-19 recovery - a longitudinal observational prospective multicenter trial

Background:

The optimal procedures to prevent, identify, monitor, and treat long-term pulmonary sequelae of COVID-19 are elusive. Here, we characterized the kinetics of respiratory and symptom recovery following COVID-19.

Methods:

We conducted a longitudinal, multicenter observational study in ambulatory and hospitalized COVID-19 patients recruited in early 2020 (n = 145). Pulmonary computed tomography (CT) and lung function (LF) readouts, symptom prevalence, and clinical and laboratory parameters were collected during acute COVID-19 and at 60, 100, and 180 days follow-up visits. Recovery kinetics and risk factors were investigated by logistic regression. Classification of clinical features and participants was accomplished by unsupervised and semi-supervised multiparameter clustering and machine learning.

Results:

At the 6-month follow-up, 49% of participants reported persistent symptoms. The frequency of structural lung CT abnormalities ranged from 18% in the mild outpatient cases to 76% in the intensive care unit (ICU) convalescents. Prevalence of impaired LF ranged from 14% in the mild outpatient cases to 50% in the ICU survivors. Incomplete radiological lung recovery was associated with increased anti-S1/S2 antibody titer, IL-6, and CRP levels at the early follow-up. We demonstrated that the risk of perturbed pulmonary recovery could be robustly estimated at early follow-up by clustering and machine learning classifiers employing solely non-CT and non-LF parameters.

Conclusions:

The severity of acute COVID-19 and protracted systemic inflammation is strongly linked to persistent structural and functional lung abnormality. Automated screening of multiparameter health record data may assist in the prediction of incomplete pulmonary recovery and optimize COVID-19 follow-up management.

Funding:

The State of Tyrol (GZ 71934), Boehringer Ingelheim/Investigator initiated study (IIS 1199-0424).

Clinical trial number:

ClinicalTrials.gov: NCT04416100

A Model Predicting Mortality of Hospitalized Covid-19 Patients Four Days After Admission: Development, Internal and Temporal-External Validation

Objective

To develop and validate a prognostic model for in-hospital mortality after four days based on age, fever at admission and five haematological parameters routinely measured in hospitalized Covid-19 patients during the first four days after admission.

Methods

Haematological parameters measured during the first 4 days after admission were subjected to a linear mixed model to obtain patient-specific intercepts and slopes for each parameter. A prediction model was built using logistic regression with variable selection and shrinkage factor estimation supported by bootstrapping. Model development was based on 481 survivors and 97 non-survivors, hospitalized before the occurrence of mutations. Internal validation was done by 10-fold cross-validation. The model was temporally-externally validated in 299 survivors and 42 non-survivors hospitalized when the Alpha variant (B.1.1.7) was prevalent.

Results

The final model included age, fever on admission as well as the slope or intercept of lactate dehydrogenase, platelet count, C-reactive protein, and creatinine. Tenfold cross validation resulted in a mean area under the receiver operating characteristic curve (AUROC) of 0.92, a mean calibration slope of 1.0023 and a Brier score of 0.076. At temporal-external validation, application of the previously developed model showed an AUROC of 0.88, a calibration slope of 0.95 and a Brier score of 0.073. Regarding the relative importance of the variables, the (apparent) variation in mortality explained by the six variables deduced from the haematological parameters measured during the first four days is higher (explained variation 0.295) than that of age (0.210).

Conclusions

The presented model requires only variables routinely acquired in hospitals, which allows immediate and wide-spread use as a decision support for earlier discharge of low-risk patients to reduce the burden on the health care system.

Clinical Trial Registration

Austrian Coronavirus Adaptive Clinical Trial (ACOVACT); ClinicalTrials.gov, identifier NCT04351724.

A proteomic survival predictor for COVID-19 patients in intensive care

Global healthcare systems are challenged by the COVID-19 pandemic. There is a need to optimize allocation of treatment and resources in intensive care, as clinically established risk assessments such as SOFA and APACHE II scores show only limited performance for predicting the survival of severely ill COVID-19 patients. Additional tools are also needed to monitor treatment, including experimental therapies in clinical trials. Comprehensively capturing human physiology, we speculated that proteomics in combination with new data-driven analysis strategies could produce a new generation of prognostic discriminators. We studied two independent cohorts of patients with severe COVID-19 who required intensive care and invasive mechanical ventilation. SOFA score, Charlson comorbidity index, and APACHE II score showed limited performance in predicting the COVID-19 outcome. Instead, the quantification of 321 plasma protein groups at 349 timepoints in 50 critically ill patients receiving invasive mechanical ventilation revealed 14 proteins that showed trajectories different between survivors and non-survivors. A predictor trained on proteomic measurements obtained at the first time point at maximum treatment level (i.e. WHO grade 7), which was weeks before the outcome, achieved accurate classification of survivors (AUROC 0.81). We tested the established predictor on an independent validation cohort (AUROC 1.0). The majority of proteins with high relevance in the prediction model belong to the coagulation system and complement cascade. Our study demonstrates that plasma proteomics can give rise to prognostic predictors substantially outperforming current prognostic markers in intensive care.

Coronavirus Disease 2019: Clinics, Treatment, and Prevention

The coronavirus disease 2019 (COVID-19) pandemic, caused by a novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), emerged at the end of 2019 in China and affected the entire world population, either by infection and its health consequences, or by restrictions in daily life as a consequence of hygiene measures and containment strategies. As of September 2021, more than 231,000.000 infections and 4,740.000 deaths due to COVID-19 have been reported. The infections present with varied clinical symptoms and severity, ranging from asymptomatic course to fatal outcome. Several risk factors for a severe course of the disease have been identified, the most important being age, gender, comorbidities, lifestyle, and genetics. While most patients recover within several weeks, some report persistent symptoms restricting their daily lives and activities, termed as post-COVID. Over the past 18months, we have acquired significant knowledge as reflected by an almost uncountable number of publications on the nature of the underlying virus and its evolution, host responses to infection, modes of transmission, and different clinical presentations of the disease. Along this line, new diagnostic tests and algorithms have been developed paralleled by the search for and clinical evaluation of specific treatments for the different stages of the disease. In addition, preventive non-pharmacological measures have been implemented to control the spread of infection in the community. While an effective antiviral therapy is not yet available, numerous vaccines including novel vaccine technologies have been developed, which show high protection from infection and specifically from a severe course or death from COVID-19. In this review, we tried to provide an up-to-date schematic of COVID-19, including aspects of epidemiology, virology, clinical presentation, diagnostics, therapy, and prevention.

Questions and answers on iron deficiency treatment selection and the use of intravenous iron in routine clinical practice

Iron deficiency is a common cause of morbidity and can arise as a consequence or complication from many diseases. The use of intravenous iron has increased significantly in the last decade, but concerns remain about indications and administration. Modern intravenous iron preparations can facilitate rapid iron repletion in one or two doses, both for absolute iron deficiency and, in the presence of inflammation, functional iron deficiency, where oral iron therapy is ineffective or has not worked. A multidisciplinary team of experts experienced in iron deficiency undertook a consensus review to support healthcare professionals with practical advice on managing iron deficiency in gastrointestinal, renal and cardiac disease, as well as; pregnancy, heavy menstrual bleeding, and surgery. We explain how intravenous iron may work where oral iron has not. We provide context on how and when intravenous iron should be administered, and informed opinion on potential benefits balanced with potential side-effects. We propose how intravenous iron side-effects can be anticipated in terms of what they may be and when they may occur. The aim of this consensus is to provide a practical basis for educating and preparing staff and patients on when and how iron infusions can be administered safely and efficiently. Key messages Iron deficiency treatment selection is driven by several factors, including the presence of inflammation, the time available for iron replenishment, and the anticipated risk of side-effects or intolerance. Intravenous iron preparations are indicated for the treatment of iron deficiency when oral preparations are ineffective or cannot be used, and therefore have applicability in a wide range of clinical contexts, including chronic inflammatory conditions, perioperative settings, and disorders associated with chronic blood loss. Adverse events occurring with intravenous iron can be anticipated according to when they typically occur, which provides a basis for educating and preparing staff and patients on how iron infusions can be administered safely and efficiently.

[Guideline S1: Long COVID: Diagnostics and treatment strategies]

This guideline comprises the state of science at the time of the editorial deadline. In view of the high turnover of knowledge the guideline is designed as a living guideline. The main objective was to provide a tool for the use in primary care, being considered well suited as a first point of entry and for the provision of care. The guideline gives recommendations on the differential diagnosis of symptoms following SARS-CoV‑2 infection, on their therapeutic options, as well as for guidance and care of the patients concerned. It also offers advice concerning return to daily life and rehabilitation. Long COVID being a very variable condition, we chose an interdisciplinary approach.

Physiology and Inflammation Driven Pathophysiology of Iron Homeostasis-Mechanistic Insights into Anemia of Inflammation and Its Treatment

Anemia is very common in patients with inflammatory disorders. Its prevalence is associated with severity of the underlying disease, and it negatively affects quality of life and cardio-vascular performance of patients. Anemia of inflammation (AI) is caused by disturbances of iron metabolism resulting in iron retention within macrophages, a reduced erythrocyte half-life, and cytokine mediated inhibition of erythropoietin function and erythroid progenitor cell differentiation. AI is mostly mild to moderate, normochromic and normocytic, and characterized by low circulating iron, but normal and increased levels of the storage protein ferritin and the iron hormone hepcidin. The primary therapeutic approach for AI is treatment of the underlying inflammatory disease which mostly results in normalization of hemoglobin levels over time unless other pathologies such as vitamin deficiencies, true iron deficiency on the basis of bleeding episodes, or renal insufficiency are present. If the underlying disease and/or anemia are not resolved, iron supplementation therapy and/or treatment with erythropoietin stimulating agents may be considered whereas blood transfusions are an emergency treatment for life-threatening anemia. New treatments with hepcidin-modifying strategies and stabilizers of hypoxia inducible factors emerge but their therapeutic efficacy for treatment of AI in ill patients needs to be evaluated in clinical trials.

Prospective epidemiological, molecular, and genetic characterization of a novel coronavirus disease in the Val Venosta/Vinschgau: the CHRIS COVID-19 study protocol

The COVID-19 pandemic has been threatening the healthcare and socioeconomic systems of entire nations. While population-based surveys to assess the distribution of SARS-CoV-2 infection have become a priority, pre-existing longitudinal studies are ideally suited to assess the determinants of COVID-19 onset and severity.The Cooperative Health Research In South Tyrol (CHRIS) study completed the baseline recruitment of 13,393 adults from the Venosta/Vinschgau rural district in 2018, collecting extensive phenotypic and biomarker data, metabolomic data, densely imputed genotype and whole-exome sequencing data.Based on CHRIS, we designed a prospective study, called CHRIS COVID-19, aimed at: 1) estimating the incidence of SARS-CoV-2 infections; 2) screening for and investigating the determinants of incident infection among CHRIS participants and their household members; 3) monitoring the immune response of infected participants prospectively.An online screening questionnaire was sent to all CHRIS participants and their household members. A random sample of 1450 participants representative of the district population was invited to assess active (nasopharyngeal swab) or past (serum antibody test) infections. We prospectively invited for complete SARS-CoV-2 testing all questionnaire completers gauged as possible cases of past infection and their household members. In positive tested individuals, antibody response is monitored quarterly for one year. Untested and negative participants receive the screening questionnaire every four weeks until gauged as possible incident cases or till the study end.Originated from a collaboration between researchers and community stakeholders, the CHRIS COVID-19 study aims at generating knowledge about the epidemiological, molecular, and genetic characterization of COVID-19 and its long-term sequelae.

Low molecular weight heparin use in COVID-19 is associated with curtailed viral persistence-a retrospective multicenter observational study

Aims 

Anticoagulation was associated with improved survival of hospitalized coronavirus disease 2019 (COVID-19) patients in large-scale studies. Yet, the development of COVID-19-associated coagulopathy (CAC) and the mechanism responsible for improved survival of anticoagulated patients with COVID-19 remain largely elusive. This investigation aimed to explore the effects of anticoagulation and low-molecular-weight heparin (LMWH) in particular on patient outcome, CAC development, thromboinflammation, cell death, and viral persistence.

Methods and results

Data of 586 hospitalized COVID-19 patients from three different regions of Austria were evaluated retrospectively. Of these, 419 (71.5%) patients received LMWH and 62 (10.5%) received non-vitamin-K oral anticoagulants (NOACs) during hospitalization. Plasma was collected at different time points in a subset of 106 patients in order to evaluate markers of thromboinflammation (H3Cit-DNA) and the cell death marker cell-free DNA (cfDNA). Use of LMWH was associated with improved survival upon multivariable Cox regression (hazard ratio = 0.561, 95% confidence interval: 0.348–0.906). Interestingly, neither LMWH nor NOAC was associated with attenuation of D-dimer increase over time, or thromboinflammation. In contrast, anticoagulation was associated with a decrease in cfDNA during hospitalization, and curtailed viral persistence was observed in patients using LMWH leading to a 4-day reduction of virus positivity upon quantitative polymerase chain reaction [13 (interquartile range: 6–24) vs. 9 (interquartile range: 5–16) days, P = 0.009].

Conclusion 

Time courses of haemostatic and thromboinflammatory biomarkers were similar in patients with and without LMWH, indicating either no effects of LMWH on haemostasis or that LMWH reduced hypercoagulability to levels of patients without LMWH. Nonetheless, anticoagulation with LMWH was associated with reduced mortality, improved markers of cell death, and curtailed viral persistence, indicating potential beneficial effects of LMWH beyond haemostasis, which encourages use of LMWH in COVID-19 patients without contraindications.

Nifedipine Potentiates Susceptibility of Salmonella Typhimurium to Different Classes of Antibiotics

The calcium channel blocker nifedipine induces cellular iron export, thereby limiting the availability of the essential nutrient iron for intracellular pathogens, resulting in bacteriostatic activity. To study if nifedipine may exert a synergistic anti-microbial activity when combined with antibiotics, we used the mouse macrophage cell line RAW267.4, infected with the intracellular bacterium Salmonella Typhimurium, and exposed the cells to varying concentrations of nifedipine and/or ampicillin, azithromycin and ceftriaxone. We observed a significant additive effect of nifedipine in combination with various antibiotics, which was not observed when using Salmonella, with defects in iron uptake. Of interest, increasing intracellular iron levels increased the bacterial resistance to treatment with antibiotics or nifedipine or their combination. We further showed that nifedipine increases the expression of the siderophore-binding peptide lipocalin-2 and promotes iron storage within ferritin, where the metal is less accessible for bacteria. Our data provide evidence for an additive effect of nifedipine with conventional antibiotics against Salmonella, which is partly linked to reduced bacterial access to iron.

Baseline iron status and presence of anaemia determine the course of systemic Salmonella infection following oral iron supplementation in mice

BACKGROUND

Iron deficiency anaemia (IDA) is a major health concern. However, preventive iron supplementation in regions with high burden of infectious diseases resulted in an increase of infection related morbidity and mortality.

METHODS

We fed male C57BL/6N mice with either an iron deficient or an iron adequate diet. Next, they received oral iron supplementation or placebo followed by intraperitoneal infection with Salmonella Typhimurium (S.Tm).

FINDINGS

We found that mice with IDA had a poorer clinical outcome than mice on an iron adequate diet. Interestingly, iron supplementation of IDA mice resulted in higher bacterial burden in organs and shortened survival. Increased transferrin saturation and non-transferrin bound iron in the circulation together with low expression of ferroportin facilitated the access of the pathogen to iron and promoted bacterial growth. Anaemia, independent of iron supplementation, was correlated with reduced neutrophil counts and cytotoxic T cells. With iron supplementation, anaemia additionally correlated with increased splenic levels of the cytokine IL-10, which is suggestive for a weakened immune control to S.Tm infection.

INTERPRETATION

Supplementing iron to anaemic mice worsens the clinical course of bacterial infection. This can be traced back to increased iron delivery to bacteria along with an impaired anti-microbial immune response. Our findings may have important implications for iron supplementation strategies in areas with high endemic burden of infections, putting those individuals, who potentially profit most from iron supplementation for anaemia, at the highest risk for infections.

FUNDING

Financial support by the Christian Doppler Laboratory for Iron Metabolism and Anemia Research.

Anemia of Chronic Disease in Patients With Cardiovascular Disease

Objective: Anemia is often found in patients with coronary artery disease (CAD) or acute coronary syndrome (ACS) and related to disease severity. Our study investigated the relationship between anemia, iron homeostasis and inflammation in CAD and examined their influence on the outcome of patients. Patients and Methods: Markers of immune activation (neopterin, interleukin [IL]-12, IL-6, high sensitive C-reactive protein (hsCRP), fibrinogen, serum amyloid A [SAA]) and iron metabolism (ferritin, transferrin saturation, hemoglobin) were determined in 2,082 patients (68.7 % men, median age 63 years) from the Ludwigshafen Risk and cardiovascular Health (LURIC) cohort. Patients were followed-up for a median of 9.81 years. Results: 960 patients (46.1 %) presented with chronic CAD, 645 patients (31.0 %) had an ACS, and 477 patients (22.9 %) presented with no CAD in coronary angiography (CAG). Anemia (n = 357, 17.1 %) was associated with disease severity (reflected by more progressed stenosis in CAG, CCS, and NYHA classes, and a lower LV-EF), a higher cardio-cerebrovascular event rate and higher levels of inflammatory markers. Interestingly, anemia was only predictive for an adverse outcome in patients with elevated inflammatory markers. Accordingly, anemia of chronic disease (ACD) was associated with a higher cardio-cerebrovascular event-rate in the subsequent 2 years as compared to patients with other types of anemia or without anemia (14.3 vs. 6.1 vs. 4.0%, p < 0.001). Conclusions: This study confirms that anemia and immune activation are strongly related to cardiovascular disease progression and an adverse outcome. Our data suggest that the association of anemia with disease severity and outcome might mainly be due to underlying inflammation.

P–196 Bacterial influence on oocyte quality - the secret of a successful fertilization

Study question

Is there a difference in bacterial composition of follicular fluid between oocytes developing a good quality blastocyst and oocytes that fail fertilization?

Summary answer

Follicular fluids of oocytes failing fertilization show a different bacterial profile compared to follicular fluids of oocytes that were successfully fertilized.

What is known already

The presence of pathogens in the female reproductive tract has been intensively investigated. Lactobacillus species are mainly associated with a healthy genital tract and good prognosis for a successful pregnancy. Studies of the bacterial composition of follicular fluids have been mainly undertaken in women participating in reproductive medicine treatment because of the nature to obtain the specimen. In most studies follicular fluids have been pooled for analysis. Information on separately collected follicular fluids is still rare. We hypothesized that the composition of bacteria within follicular fluids is responsible for the success of the fertilization process.

Study design, size, duration

The study was designed and conducted at the Kinderwunsch Institut Schenk GmbH (Dobl, Austria) together with DNA-Technology. Follicular fluids from 46 patients undergoing IVF (in vitro fertilization) and ICSI (intracytoplasmic sperm injection) treatment were included and analyzed.

Participants/materials, setting, methods

Follicular fluids from 46 patients were collected separately. 2 follicular fluids from each patient were screened for common bacteria of the genital tract. One from an oocyte developing a good quality blastocyst and one displaying fertilization failures. Samples were analyzed for bacterial composition using the Femoflor16 (DNA-Technology).

Main results and the role of chance

Quantitative analysis revealed a higher total bacteria mass in follicles from oocytes that failed fertilization. Furthermore, Lactobacillus were not present in those follicles compared to good blastocyst follicles. In addition, Chlamydia trachomatis was found mainly in follicular fluid of not fertilized oocytes together with Eubacterium, Gardnarella and Trichomonas species. Interestingly, a trend of elevated levels of Ureaplasma species in follicular fluids of oocytes developing good quality blastocysts was observed.

Limitations, reasons for caution

Contamination of follicular fluids due to the procedure of oocyte pick up and follicular fluid retrieval cannot be completely excluded. Results should be confirmed with a higher sample size.

Wider implications of the findings: We assume that different bacterial compositions in follicular fluids are responsible for the destiny of the oocyte. It is tempting to speculate that bacterial analysis of follicular fluids may be beneficial to select to best oocytes in future IVF/ICSI treatments.

Trial registration number

Not applicable

Discontinuation versus continuation of renin-angiotensin-system inhibitors in COVID-19 (ACEI-COVID): a prospective, parallel group, randomised, controlled, open-label trial

BACKGROUND

SARS-CoV-2 entry in human cells depends on angiotensin-converting enzyme 2, which can be upregulated by inhibitors of the renin-angiotensin system (RAS). We aimed to test our hypothesis that discontinuation of chronic treatment with ACE-inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) mitigates the course o\f recent-onset COVID-19.

METHODS

ACEI-COVID was a parallel group, randomised, controlled, open-label trial done at 35 centres in Austria and Germany. Patients aged 18 years and older were enrolled if they presented with recent symptomatic SARS-CoV-2 infection and were chronically treated with ACEIs or ARBs. Patients were randomly assigned 1:1 to discontinuation or continuation of RAS inhibition for 30 days. Primary outcome was the maximum sequential organ failure assessment (SOFA) score within 30 days, where death was scored with the maximum achievable SOFA score. Secondary endpoints were area under the death-adjusted SOFA score (AUCSOFA), mean SOFA score, admission to the intensive care unit, mechanical ventilation, and death. Analyses were done on a modified intention-to-treat basis. This trial is registered with ClinicalTrials.gov, NCT04353596.

FINDINGS

Between April 20, 2020, and Jan 20, 2021, 204 patients (median age 75 years [IQR 66-80], 37% females) were randomly assigned to discontinue (n=104) or continue (n=100) RAS inhibition. Within 30 days, eight (8%) of 104 died in the discontinuation group and 12 (12%) of 100 patients died in the continuation group (p=0·42). There was no significant difference in the primary endpoint between the discontinuation and continuation group (median [IQR] maximum SOFA score 0·00 (0·00-2·00) vs 1·00 (0·00-3·00); p=0·12). Discontinuation was associated with a significantly lower AUCSOFA (0·00 [0·00-9·25] vs 3·50 [0·00-23·50]; p=0·040), mean SOFA score (0·00 [0·00-0·31] vs 0·12 [0·00-0·78]; p=0·040), and 30-day SOFA score (0·00 [10-90th percentile, 0·00-1·20] vs 0·00 [0·00-24·00]; p=0·023). At 30 days, 11 (11%) in the discontinuation group and 23 (23%) in the continuation group had signs of organ dysfunction (SOFA score ≥1) or were dead (p=0·017). There were no significant differences for mechanical ventilation (10 (10%) vs 8 (8%), p=0·87) and admission to intensive care unit (20 [19%] vs 18 [18%], p=0·96) between the discontinuation and continuation group.

INTERPRETATION

Discontinuation of RAS-inhibition in COVID-19 had no significant effect on the maximum severity of COVID-19 but may lead to a faster and better recovery. The decision to continue or discontinue should be made on an individual basis, considering the risk profile, the indication for RAS inhibition, and the availability of alternative therapies and outpatient monitoring options.

FUNDING

Austrian Science Fund and German Center for Cardiovascular Research.

Pharmacological Targeting of BMP6-SMAD Mediated Hepcidin Expression Does Not Improve the Outcome of Systemic Infections With Intra-Or Extracellular Gram-Negative Bacteria in Mice

Introduction

Hepcidin is the systemic master regulator of iron metabolism as it degrades the cellular iron exporter ferroportin. In bacterial infections, hepcidin is upregulated to limit circulating iron for pathogens, thereby increasing iron retention in macrophages. This mechanism withholds iron from extracellular bacteria but could be of disadvantage in infections with intracellular bacteria. We aimed to understand the role of hepcidin in infections with intra- or extracellular bacteria using different hepcidin inhibitors.

Methods

For the experiments LDN-193189 and oversulfated heparins were used, which interact with the BMP6-SMAD pathway thereby inhibiting hepcidin expression. We infected male C57BL/6N mice with either the intracellular bacterium Salmonella Typhimurium or the extracellular bacterium Escherichia coli and treated these mice with the different hepcidin inhibitors.

Results

Both inhibitors effectively reduced hepcidin levels in vitro under steady state conditions and upon stimulation with the inflammatory signals interleukin-6 or lipopolysaccharide. The inhibitors also reduced hepcidin levels and increased circulating iron concentration in uninfected mice. However, both compounds failed to decrease liver- and circulating hepcidin levels in infected mice and did not affect ferroportin expression in the spleen or impact on serum iron levels. Accordingly, both BMP-SMAD signaling inhibitors did not influence bacterial numbers in different organs in the course of E.coli or S.Tm sepsis.

Conclusion

These data indicate that targeting the BMP receptor or the BMP-SMAD pathway is not sufficient to suppress hepcidin expression in the course of infection with both intra- or extracellular bacteria. This suggests that upon pharmacological inhibition of the central SMAD-BMP pathways during infection, other signaling cascades are compensatorily induced to ensure sufficient hepcidin formation and iron restriction to circulating microbes.

Cytokine-Mediated Regulation of ARG1 in Macrophages and Its Impact on the Control of Salmonella enterica Serovar Typhimurium Infection

Arginase 1 (ARG1) is a cytosolic enzyme that cleaves L-arginine, the substrate of inducible nitric oxide synthase (iNOS), and thereby impairs the control of various intracellular pathogens. Herein, we investigated the role of ARG1 during infection with Salmonella enterica serovar Typhimurium (S.tm). To study the impact of ARG1 on Salmonella infections in vitro, bone marrow-derived macrophages (BMDM) from C57BL/6N wild-type, ARG1-deficient Tie2Cre+/-ARG1fl/fl and NRAMPG169 C57BL/6N mice were infected with S.tm. In wild-type BMDM, ARG1 was induced by S.tm and further upregulated by the addition of interleukin (IL)-4, whereas interferon-γ had an inhibitory effect. Deletion of ARG1 did not result in a reduction in bacterial numbers. In vivo, Arg1 mRNA was upregulated in the spleen, but not in the liver of C57BL/6N mice following intraperitoneal S.tm infection. The genetic deletion of ARG1 (Tie2Cre+/-ARG1fl/fl) or its pharmacological inhibition with CB-1158 neither affected the numbers of S.tm in spleen, liver and blood nor the expression of host response genes such as iNOS, IL-6 or tumour necrosis factor (TNF). Furthermore, ARG1 was dispensable for pathogen control irrespective of the presence or absence of the phagolysosomal natural resistance-associated macrophage protein 1 (NRAMP1). Thus, unlike the detrimental function of ARG1 seen during infections with other intraphagosomal microorganisms, ARG1 did not support bacterial survival in systemic salmonellosis, indicating differential roles of arginine metabolism for host immune response and microbe persistence depending on the type of pathogen.

Testosterone Deficiency Is a Risk Factor for Severe COVID-19

Background

Male sex is related to increased COVID-19 severity and fatality although confirmed infections are similarly distributed between men and women. The aim of this retrospective analysis was to investigate the impact of sex hormones on disease progression and immune activation in men with COVID-19.

Patients and Methods

We studied for effects of sex hormones on disease severity and immune activation in 377 patients (230 men, 147 women) with PCR-confirmed SARS-CoV-2 infections hospitalized at the Innsbruck University Hospital between February and December 2020.

Results

Men had more severe COVID-19 with concomitant higher immune system activation upon hospital admission when compared to women. Men with a severe course of infection had lower serum total testosterone (tT) levels whereas luteinizing hormone (LH) and estradiol (E2) levels were within the normal range. tT deficiency was associated with elevated CRP (rs = - 0.567, p < 0.001), IL-6 levels (rs = - 0.563, p < 0.001), lower cholesterol levels (rs = 0.407, p < 0.001) and an increased morbidity and mortality. Men with tT levels < 100 ng/dL had a more than eighteen-fold higher in-hospital mortality risk (OR 18.243 [95%CI 2.301 - 144.639], p = 0.006) compared to men with tT levels > 230 ng/dL. Moreover, while morbidity and mortality showed a positive correlation with E2 levels at admission, we detected a negative correlation with the tT/E2 ratio upon hospital admission.

Conclusion

Hospitalized men with COVID-19 present with rather low testosterone levels linked to more advanced immune activation, severe clinical manifestations translating into an increased risk for ICU admission or death. The underlying mechanisms remain elusive but may include infection driven hypogonadism as well as inflammation mediated cholesterol reduction causing gonadotropin suppression and impaired androgen formation. Finally, in elderly late onset hypogonadism might also contribute to lower testosterone levels.

Regulation of Th1 T Cell Differentiation by Iron via Upregulation of T Cell Immunoglobulin and Mucin Containing Protein-3 (TIM-3)

Iron plays an important role in host–pathogen interactions, in being an essential element for both pathogen and host metabolism, but also by impacting immune cell differentiation and anti-microbial effector pathways. Iron has been implicated to affect the differentiation of T lymphocytes during inflammation, however, so far the underlying mechanism remained elusive. In order to study the role of iron in T cell differentiation we here investigated how dietary iron supplementation affects T cell function and outcome in a model of chronic infection with the intracellular bacterium Salmonella enterica serovar typhimurium (S. Typhimurium). Iron loading prior to infection fostered bacterial burden and, unexpectedly, reduced differentiation of CD4⁺ T helper cells type 1 (Th1) and expression of interferon-gamma (IFNγ), a key cytokine to control infections with intracellular pathogens. This effect could be traced back to iron-mediated induction of the negative immune checkpoint regulator T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3), expressed on the surface of this T cell subset. In vitro experiments demonstrated that iron supplementation specifically upregulated mRNA and protein expression of TIM-3 in naïve Th cells in a dose-depdendent manner and hindered priming of those T cells towards Th1 differentiation. Importantly, administration of TIM-3 blocking antibodies to iron-loaded mice infected with S. Typhimurium virtually restored Th1 cell differentiation and significantly improved bacterial control. Our data uncover a novel mechanism by which iron modulates CD4⁺ cell differentiation and functionality and hence impacts infection control with intracellular pathogens. Specifically, iron inhibits the differentiation of naive CD4⁺ T cells to protective IFNγ producing Th1 lymphocytes via stimulation of TIM-3 expression. Finally, TIM-3 may serve as a novel drug target for the treatment of chronic infections with intracellular pathogens, specifically in iron loading diseases.

A comprehensive antigen production and characterisation study for easy-to-implement, specific and quantitative SARS-CoV-2 serotests

BACKGROUND

Antibody tests are essential tools to investigate humoral immunity following SARS-CoV-2 infection or vaccination. While first-generation antibody tests have primarily provided qualitative results, accurate seroprevalence studies and tracking of antibody levels over time require highly specific, sensitive and quantitative test setups.

METHODS

We have developed two quantitative, easy-to-implement SARS-CoV-2 antibody tests, based on the spike receptor binding domain and the nucleocapsid protein. Comprehensive evaluation of antigens from several biotechnological platforms enabled the identification of superior antigen designs for reliable serodiagnostic. Cut-off modelling based on unprecedented large and heterogeneous multicentric validation cohorts allowed us to define optimal thresholds for the tests' broad applications in different aspects of clinical use, such as seroprevalence studies and convalescent plasma donor qualification.

FINDINGS

Both developed serotests individually performed similarly-well as fully-automated CE-marked test systems. Our described sensitivity-improved orthogonal test approach assures highest specificity (99.8%); thereby enabling robust serodiagnosis in low-prevalence settings with simple test formats. The inclusion of a calibrator permits accurate quantitative monitoring of antibody concentrations in samples collected at different time points during the acute and convalescent phase of COVID-19 and disclosed antibody level thresholds that correlate well with robust neutralization of authentic SARS-CoV-2 virus.

INTERPRETATION

We demonstrate that antigen source and purity strongly impact serotest performance. Comprehensive biotechnology-assisted selection of antigens and in-depth characterisation of the assays allowed us to overcome limitations of simple ELISA-based antibody test formats based on chromometric reporters, to yield comparable assay performance as fully-automated platforms.

FUNDING

WWTF, Project No. COV20-016; BOKU, LBI/LBG.

Cardiopulmonary recovery after COVID-19: an observational prospective multicentre trial

BACKGROUND

After the 2002/2003 severe acute respiratory syndrome outbreak, 30% of survivors exhibited persisting structural pulmonary abnormalities. The long-term pulmonary sequelae of coronavirus disease 2019 (COVID-19) are yet unknown, and comprehensive clinical follow-up data are lacking.

METHODS

In this prospective, multicentre, observational study, we systematically evaluated the cardiopulmonary damage in subjects recovering from COVID-19 at 60 and 100 days after confirmed diagnosis. We conducted a detailed questionnaire, clinical examination, laboratory testing, lung function analysis, echocardiography and thoracic low-dose computed tomography (CT).

RESULTS

Data from 145 COVID-19 patients were evaluated, and 41% of all subjects exhibited persistent symptoms 100 days after COVID-19 onset, with dyspnoea being most frequent (36%). Accordingly, patients still displayed an impaired lung function, with a reduced diffusing capacity in 21% of the cohort being the most prominent finding. Cardiac impairment, including a reduced left ventricular function or signs of pulmonary hypertension, was only present in a minority of subjects. CT scans unveiled persisting lung pathologies in 63% of patients, mainly consisting of bilateral ground-glass opacities and/or reticulation in the lower lung lobes, without radiological signs of pulmonary fibrosis. Sequential follow-up evaluations at 60 and 100 days after COVID-19 onset demonstrated a vast improvement of symptoms and CT abnormalities over time.

CONCLUSION

A relevant percentage of post-COVID-19 patients presented with persisting symptoms and lung function impairment along with radiological pulmonary abnormalities >100 days after the diagnosis of COVID-19. However, our results indicate a significant improvement in symptoms and cardiopulmonary status over time.

Targeted COVID-19 Vaccination (TAV-COVID) Considering Limited Vaccination Capacities-An Agent-Based Modeling Evaluation

(1) Background: The Austrian supply of COVID-19 vaccine is limited for now. We aim to provide evidence-based guidance to the authorities in order to minimize COVID-19-related hospitalizations and deaths in Austria. (2) Methods: We used a dynamic agent-based population model to compare different vaccination strategies targeted to the elderly (65 ≥ years), middle aged (45-64 years), younger (15-44 years), vulnerable (risk of severe disease due to comorbidities), and healthcare workers (HCW). First, outcomes were optimized for an initially available vaccine batch for 200,000 individuals. Second, stepwise optimization was performed deriving a prioritization sequence for 2.45 million individuals, maximizing the reduction in total hospitalizations and deaths compared to no vaccination. We considered sterilizing and non-sterilizing immunity, assuming a 70% effectiveness. (3) Results: Maximum reduction of hospitalizations and deaths was achieved by starting vaccination with the elderly and vulnerable followed by middle-aged, HCW, and younger individuals. Optimizations for vaccinating 2.45 million individuals yielded the same prioritization and avoided approximately one third of deaths and hospitalizations. Starting vaccination with HCW leads to slightly smaller reductions but maximizes occupational safety. (4) Conclusion: To minimize COVID-19-related hospitalizations and deaths, our study shows that elderly and vulnerable persons should be prioritized for vaccination until further vaccines are available.