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Background: The peak of the global COVID-19 pandemic has not yet been reached, and many countries face the prospect of a second wave of infections before effective vaccinations will be available. After an initial phase of viral replication, some patients develop a second illness phase in which the host thrombotic and inflammatory responses seem to drive complications. Severe COVID-19 disease is linked to high mortality, hyperinflammation, and a remarkably high incidence of thrombotic events. We hypothesize a crucial pathophysiological role for the contact pathway of coagulation and the kallikrein-bradykinin pathway. Therefore, drugs that modulate this excessive thromboinflammatory response should be investigated in severe COVID-19., Methods: In this adaptive, open-label multicenter randomized clinical trial, we compare low molecular weight heparins at 50 IU anti-Xa/kg twice daily-or 75 IU anti-Xa twice daily for intensive care (ICU) patients-in combination with aprotinin to standard thromboprophylaxis in hospitalized COVID-19 patients. In the case of hyperinflammation, the interleukin-1 receptor antagonist anakinra will be added on top of the drugs in the interventional arm. In a pilot phase, the effect of the intervention on thrombotic markers (D-dimer) will be assessed. In the full trial, the primary outcome is defined as the effect of the interventional drugs on clinical status as defined by the WHO ordinal scale for clinical improvement., Discussion: In this trial, we target the thromboinflammatory response at multiple levels. We intensify the dose of low molecular weight heparins to reduce thrombotic complications. Aprotinin is a potent kallikrein pathway inhibitor that reduces fibrinolysis, activation of the contact pathway of coagulation, and local inflammatory response. Additionally, aprotinin has shown in vitro inhibitory effects on SARS-CoV-2 cellular entry. Because the excessive thromboinflammatory response is one of the most adverse prognostic factors in COVID-19, we will add anakinra, a recombinant interleukin-1 receptor antagonist, to the regimen in case of severely increased inflammatory parameters. This way, we hope to modulate the systemic response to SARS-CoV-2 and avoid disease progressions with a potentially fatal outcome., Trial Registration: The EU Clinical Trials Register 2020-001739-28 . Registered on April 10, 2020.

Background: Invasive fungal infections (IFI) are difficult to diagnose, especially in critically ill patients. As the mannose receptor (MR) is shed from macrophage cell surfaces after exposure to fungi, we investigate whether its soluble serum form (sMR) can serve as a biomarker of IFI., Methods: This is a secondary analysis of the multicentre randomised controlled trial (EPaNIC, n = 4640) that investigated the impact of initiating supplemental parenteral nutrition (PN) early during critical illness (Early-PN) as compared to withholding it in the first week of intensive care (Late-PN). Serum sMR concentrations were measured in three matched patient groups (proven/probable IFI, n = 82; bacterial infection, n = 80; non-infectious inflammation, n = 77) on the day of antimicrobial initiation or matched intensive care unit day and the five preceding days, as well as in matched healthy controls (n = 59). Independent determinants of sMR concentration were identified via multivariable linear regression. Serum sMR time profiles were analysed with repeated-measures ANOVA. Predictive properties were assessed via area under the receiver operating curve (aROC)., Results: Serum sMR was higher in IFI patients than in all other groups (all p < 0.02), aROC to differentiate IFI from no IFI being 0.65 (p < 0.001). The ability of serum sMR to discriminate infectious from non-infectious inflammation was better with an aROC of 0.68 (p < 0.001). The sMR concentrations were already elevated up to 5 days before antimicrobial initiation and remained stable over time. Multivariable linear regression analysis showed that an infection or an IFI, higher severity of illness and sepsis upon admission were associated with higher sMR levels; urgent admission and Late-PN were independently associated with lower sMR concentrations., Conclusion: Serum sMR concentrations were higher in critically ill patients with IFI than in those with a bacterial infection or with non-infectious inflammation. However, test properties were insufficient for diagnostic purposes.

Abstract Background Research in recent years firmly established that microglial cells play an important role in the pathogenesis of Alzheimer's disease (AD). In parallel, a series of studies showed that, under both homeostatic and pathological conditions, microglia are a heterogeneous cell population. In AD, amyloid-β (Aβ) plaque-associated microglia (PAM) display a clearly distinct phenotype compared to plaque-distant microglia (PCM), suggesting that these two microglia subtypes likely differently contribute to disease progression. So far, molecular characterization of PAM was performed indirectly using single cell RNA sequencing (scRNA-seq) approaches or based on markers that are supposedly up-regulated in this microglia subpopulation. Methods In this study based on a well-characterized AD mouse model, we combined cell-specific laser capture microdissection and RNA-seq analysis to i) identify, without preconceived notions of the molecular and/or functional changes that would affect these cells, the genes and gene networks that are dysregulated in PAM or PCM at three critical stages of the disease, and ii) to investigate the potential contribution of both plaque-associated and plaque-distant microglia. Results First, we established that our approach allows selective isolation of microglia, while preserving spatial information and preventing transcriptome changes induced by classical purification approaches. Then, we identified, in PAM and PCM subpopulations, networks of co-deregulated genes and analyzed their potential functional roles in AD. Finally, we investigated the dynamics of microglia transcriptomic remodeling at early, intermediate and late stages of the disease and validated select findings in postmortem human AD brain. Conclusions Our comprehensive study provides useful transcriptomic information regarding the respective contribution of PAM and PCM across the Aβ pathology progression. It highlights specific pathways that would require further study to decipher their roles across disease progression. It demonstrates that the proximity of microglia to Aβ-plaques dramatically alters the microglial transcriptome and reveals that these changes can have both positive and negative impacts on the surrounding cells. These opposing effects may be driven by local microglia heterogeneity also demonstrated by this study. Our approach leads to molecularly define the less well studied plaque-distant microglia. We show that plaque-distant microglia are not bystanders of the disease, although the transcriptomic changes are far less striking compared to what is observed in plaque-associated microglia. In particular, our results suggest they may be involved in Aβ oligomer detection and in Aβ-plaque initiation, with increased contribution as the disease progresses. Graphical Abstract

Abstract Background Thromboinflammation plays a central role in severe COVID‐19. The kallikrein pathway activates both inflammatory pathways and contact‐mediated coagulation. We investigated if modulation of the thromboinflammatory response improves outcomes in hospitalized COVID‐19 patients. Methods In this multicenter open‐label randomized clinical trial (EudraCT 2020‐001739‐28), patients hospitalized with COVID‐19 were 1:2 randomized to receive standard of care (SOC) or SOC plus study intervention. The intervention consisted of aprotinin (2,000,000 IE IV four times daily) combined with low molecular weight heparin (LMWH; SC 50 IU/kg twice daily on the ward, 75 IU/kg twice daily in intensive care). Additionally, patients with predefined hyperinflammation received the interleukin‐1 receptor antagonist anakinra (100 mg IV four times daily). The primary outcome was time to a sustained 2‐point improvement on the 7‐point World Health Organization ordinal scale for clinical status, or discharge. Findings Between 24 June 2020 and 1 February 2021, 105 patients were randomized, and 102 patients were included in the full analysis set (intervention N = 67 vs. SOC N = 35). Twenty‐five patients from the intervention group (37%) received anakinra. The intervention did not affect the primary outcome (HR 0.77 [CI 0.50‐1.19], p = 0.24) or mortality (intervention n = 3 [4.6%] vs. SOC n = 2 [5.7%], HR 0.82 [CI 0.14‐4.94], p = 0.83). There was one treatment‐related adverse event in the intervention group (hematuria, 1.49%). There was one thrombotic event in the intervention group (1.49%) and one in the SOC group (2.86%), but no major bleeding. Conclusions In hospitalized COVID‐19 patients, modulation of thromboinflammation with high‐dose aprotinin and LMWH with or without anakinra did not improve outcome in patients with moderate to severe COVID‐19.

Abstract Background Invasive fungal infections (IFI) are difficult to diagnose, especially in critically ill patients. As the mannose receptor (MR) is shed from macrophage cell surfaces after exposure to fungi, we investigate whether its soluble serum form (sMR) can serve as a biomarker of IFI. Methods This is a secondary analysis of the multicentre randomised controlled trial (EPaNIC, n = 4640) that investigated the impact of initiating supplemental parenteral nutrition (PN) early during critical illness (Early-PN) as compared to withholding it in the first week of intensive care (Late-PN). Serum sMR concentrations were measured in three matched patient groups (proven/probable IFI, n = 82; bacterial infection, n = 80; non-infectious inflammation, n = 77) on the day of antimicrobial initiation or matched intensive care unit day and the five preceding days, as well as in matched healthy controls (n = 59). Independent determinants of sMR concentration were identified via multivariable linear regression. Serum sMR time profiles were analysed with repeated-measures ANOVA. Predictive properties were assessed via area under the receiver operating curve (aROC). Results Serum sMR was higher in IFI patients than in all other groups (all p