Nico Janssen

Mr. Nico Janssen

Radboudumc, Nijmegen, The Netherlands
orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 June 2020 in Intensive Care Medicine
Verified
Journal Article
Open access
PDF file
PVPaul Verweij
Paul Verweij
BRBart Rijnders
Bart Rijnders
RBRoger J. M. Brüggemann
Roger J. M. Brüggemann
EAElie Azoulay
Elie Azoulay
MBMatteo Bassetti
Matteo Bassetti
FVFrank van de Veerdonk
Frank van de Veerdonk
Purpose Invasive pulmonary aspergillosis is increasingly reported in patients with influenza admitted to the intensive care unit (ICU). Classification of patients with influenza-associated pulmonary aspergillosis (IAPA) using the current definitions for invasive fungal diseases has proven difficult, and our aim was to develop case definitions for IAPA that can facilitate clinical studies. Methods A group of 29 international experts reviewed current insights into the epidemiology, diagnosis and management of IAPA and proposed a case definition of IAPA through a process of informal consensus. Results Since IAPA may develop in a wide range of hosts, an entry criterion was proposed and not host factors. The entry criterion was defined as a patient requiring ICU admission for respiratory distress with a positive influenza test temporally related to ICU admission. In addition, proven IAPA required histological evidence of invasive septate hyphae and mycological evidence for Aspergillus. Probable IAPA required the detection of galactomannan or positive Aspergillus culture in bronchoalveolar lavage (BAL) or serum with pulmonary infiltrates or a positive culture in upper respiratory samples with bronchoscopic evidence for tracheobronchitis or cavitating pulmonary infiltrates of recent onset. The IAPA case definitions may be useful to classify patients with COVID-19-associated pulmonary aspergillosis (CAPA), while awaiting further studies that provide more insight into the interaction between Aspergillus and the SARS-CoV-2-infected lung. Conclusion A consensus case definition of IAPA is proposed, which will facilitate research into the epidemiology, diagnosis and management of this emerging acute and severe Aspergillus disease, and may be of use to study CAPA.

24 October 2020 in Infectious Diseases
Verified
Journal Article
Open access
ZKZara Karami
Zara Karami
BKBram T. Knoop
Bram T. Knoop
ADAnton S. M. Dofferhoff
Anton S. M. Dofferhoff
MBMarc J. T. Blaauw
Marc J. T. Blaauw
Nico JanssenNico Janssen
Nico Janssen
JOJaap ten Oever
Jaap ten Oever
Knowledge on bacterial co-infections in COVID-19 is crucial to use antibiotics appropriately. Therefore, we aimed to determine the incidence of bacterial co-infections, antibiotic use and applicati...

6 October 2020 in Frontiers in Immunology
Verified
Journal Article
Open access
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BBBaranca Buijsers
Baranca Buijsers
CYCansu Yanginlar
Cansu Yanginlar
ANAline de Nooijer
Aline de Nooijer
IGInge Grondman
Inge Grondman
MMMarissa L. Maciej-Hulme
Marissa L. Maciej-Hulme
JVJohan van der Vlag
Johan van der Vlag
Reports suggest a role of endothelial dysfunction and loss of endothelial barrier function in COVID-19. It is well established that the endothelial glycocalyx-degrading enzyme heparanase contributes to vascular leakage and inflammation. Low molecular weight heparins (LMWH) serve as an inhibitor of heparanase. We hypothesize that heparanase contributes to the pathogenesis of COVID-19, and that heparanase may be inhibited by LMWH. To test this hypothesis, heparanase activity and heparan sulfate levels were measured in plasma of healthy controls (n = 10) and COVID-19 patients (n = 48). Plasma heparanase activity and heparan sulfate levels were significantly elevated in COVID-19 patients. Heparanase activity was associated with disease severity including the need for intensive care, lactate dehydrogenase levels, and creatinine levels. Use of prophylactic LMWH in non-ICU patients was associated with a reduced heparanase activity. Since there is no other clinically applied heparanase inhibitor currently available, therapeutic treatment of COVID-19 patients with low molecular weight heparins should be explored.

10 October 2020 in The Journal of Infectious Diseases
Verified
Journal Article
Open access
ANAline H de Nooijer
Aline H de Nooijer
IGInge Grondman
Inge Grondman
Nico JanssenNico Janssen
Nico Janssen
MNMihai G Netea
Mihai G Netea
LWLoek Willems
Loek Willems
MKMargreet Klop-Riehl
Margreet Klop-Riehl
Background: Excessive activation of immune responses in coronavirus disease 2019 (COVID-19) is considered to be related to disease severity, complications, and mortality rate. The complement system is an important component of innate immunity and can stimulate inflammation, but its role in COVID-19 is unknown. Methods: A prospective, longitudinal, single center study was performed in hospitalized patients with COVID-19. Plasma concentrations of complement factors C3a, C3c, and terminal complement complex (TCC) were assessed at baseline and during hospital admission. In parallel, routine laboratory and clinical parameters were collected from medical files and analyzed. Results: Complement factors C3a, C3c, and TCC were significantly increased in plasma of patients with COVID-19 compared with healthy controls (P < .05). These complement factors were especially elevated in intensive care unit patients during the entire disease course (P < .005 for C3a and TCC). More intense complement activation was observed in patients who died and in those with thromboembolic events. Conclusions: Patients with COVID-19 demonstrate activation of the complement system, which is related to disease severity. This pathway may be involved in the dysregulated proinflammatory response associated with increased mortality rate and thromboembolic complications. Components of the complement system might have potential as prognostic markers for disease severity and as therapeutic targets in COVID-19.

10 December 2020 in Critical Care
Verified
Journal Article
Open access
PDF file
EKEmma J. Kooistra
Emma J. Kooistra
NWNicole J. B. Waalders
Nicole J. B. Waalders
IGInge Grondman
Inge Grondman
Nico JanssenNico Janssen
Nico Janssen
ANAline H. de Nooijer
Aline H. de Nooijer
PPPeter Pickkers
Peter Pickkers
Background: A subset of critically ill COVID-19 patients develop a hyperinflammatory state. Anakinra, a recombinant interleukin-1 receptor antagonist, is known to be effective in several hyperinflammatory diseases. We investigated the effects of anakinra on inflammatory parameters and clinical outcomes in critically ill, mechanically ventilated COVID-19 patients with clinical features of hyperinflammation. Methods: In this prospective cohort study, 21 critically ill COVID-19 patients treated with anakinra were compared to a group of standard care. Serial data of clinical inflammatory parameters and concentrations of multiple circulating cytokines were determined and aligned on start day of anakinra in the treatment group, and median start day of anakinra in the control group. Analysis was performed for day − 10 to + 10 relative to alignment day. Clinical outcomes were analyzed during 28 days. Additionally, three sensitivity analyses were performed: (1) using propensity score-matched groups, (2) selecting patients who did not receive corticosteroids, and (3) using a subset of the control group aimed to match the criteria (fever, elevated ferritin) for starting anakinra treatment. Results: Baseline patient characteristics and clinical parameters on ICU admission were similar between groups. As a consequence of bias by indication, plasma levels of aspartate aminotransferase (ASAT) (p = 0.0002), ferritin (p = 0.009), and temperature (p = 0.001) were significantly higher in the anakinra group on alignment day. Following treatment, no relevant differences in kinetics of circulating cytokines were observed between both groups. Decreases of clinical parameters, including temperature (p = 0.03), white blood cell counts (p = 0.02), and plasma levels of ferritin (p = 0.003), procalcitonin (p = 0.001), creatinine (p = 0.01), and bilirubin (p = 0.007), were more pronounced in the anakinra group. No differences in duration of mechanical ventilation or ICU length of stay were observed between groups. Sensitivity analyses confirmed these results. Conclusions: Anakinra is effective in reducing clinical signs of hyperinflammation in critically ill COVID-19 patients. A randomized controlled trial is warranted to draw conclusion about the effects of anakinra on clinical outcomes.

29 May 2021 in Intensive Care Medicine
Verified
Journal Article
Closed access
PDF file
LVLore Vanderbeke
Lore Vanderbeke
Nico JanssenNico Janssen
Nico Janssen
DBDennis Bergmans
Dennis Bergmans
MBMarc Bourgeois
Marc Bourgeois
JBJochem Buil
Jochem Buil
TWTom Wolfs
Tom Wolfs