Abstract 1347 Cystic fibrosis transmembrane conductance regulator potentiators attenuate platelet activation and aggregation in blood of healthy donors and COVID-19 patients

Cystic fibrosis transmembrane conductance regulator (CFTR) is a Cl- channel and ABC transporter; its mutations cause the clinical picture of cystic fibrosis (CF). Of late, CFTR has also emerged as an important regulator of platelet function, as CFTR dysfunction causes agonist-induced platelet hyperactivation. These findings are reminiscent of platelets from SARS-CoV-2 infected patients since thromboembolic complications represent hallmarks of severe COVID-19 that may critically contribute to morbidity and mortality. CFTR modulators have recently been introduced as a treatment for patients with various CFTR mutations, but have also been reported by us and others to enhance channel function of wild type CFTR. We therefore postulated that CFTR modulators may exert anti-coagulant effects on platelets of COVID-19 patients.

We recruited 36 COVID-19 patients with moderate, and 34 COVID-19 patients with severe disease course (all w/o anti-platelet drugs), and 38 healthy donors (HDs). To determine the activation status of platelets, changes in surface expression of CD62p and CD63 upon pre-treatment with vehicle or the CFTR potentiator ivacaftor were analyzed by flow cytometry. Platelets were activated by the platelet agonists adenosine diphosphate (ADP) or thrombin receptor activating protein-6 (TRAP6), and analyzed for Ca2+-mobilization by FACS, by impedance aggregometry, and by a microfluidic flow assay assessing platelet adhesion after pre-treatment with or without ivacaftor.

In line with our hypothesis, we observed significant reductions in ADP- or TRAP6-induced CD62p/CD63 expression, Ca2+-mobilization, aggregation, and adhesion of platelets from HDs by pre- treatment with ivacaftor. In blood from COVID-19 patients, platelet activation correlates with disease severity, as demonstrated by a 5-fold and 8-fold increase in the proportion of CD62p+ platelets from patients with moderate and severe disease, respectively, relative to HDs. Similarly, the proportion of CD63+ platelets in patients with severe COVID-19 was 2-fold higher than in HDs. Retrospective analysis of clinical data from a total of 4,050 CF patients with COVID-19 receiving single or combination therapy of ivacaftor, lumacaftor, tezacaftor, or elexacaftor in comparison to an untreated cohort revealed that CF therapy reduced the relative risk to suffer thromboembolism-associated cardiovascular events such as heart attack or deep vein thrombosis by 50.0% or 61.1%, respectively, suggesting an anti-thrombotic effect of CFTR modulators in CF COVID-19 patients. In line with this observation, ex vivo pre-treatment of platelets from acute COVID-19 patients with ivacaftor reduced Ca2+ mobilization, adhesion, and aggregation of platelets.

Our results demonstrate an anticoagulant effect of CFTR potentiators on platelets from HDs and severe COVID-19 patients and thus, suggest CFTR potentiators as a promising strategy to reduce the risk of thrombotic events in the clinical management of COVID-19.

Clin Res Cardiol (2023). https://doi.org/10.1007/s00392-023-02180-w
Cystic fibrosis transmembrane conductance regulator potentiators attenuate platelet activation and aggregation in blood of healthy donors and COVID-19 patients
E. Asmus¹, K. Weronika¹, M. C. Brack², C. Wittig¹, F. Behrens¹, L. Reinshagen³, M. Pfeiffer², S. Schulz¹, B. Mandzimba-Maloko¹, L. Erfinanda¹, P.-L. Perret⁴, L. Michalick¹, P. J. Smeele⁵, E. H. T. Lim⁶, C. E. van den Brom⁶, A. B. A. Vonk⁶, T. Kaiser⁷, N. Suttorp², S. Hippenstiel², L. E. Sander², F. Kurth², U. Rauch-Kröhnert³, U. Landmesser³, A. Haghikia³, R. Preißner¹, H. J. Bogaard⁵, M. Witzenrath², W. M. Kuebler¹, R. Szulcek¹, S. Simmons⁸
¹Institut für Physiologie, Charité - Universitätsmedizin Berlin, Berlin; ²Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin; ³CC 11: Med. Klinik für Kardiologie, Charité - Universitätsmedizin Berlin, Berlin; ⁴CC2: Institut für Physiologie, CCO, Charité - Universitätsmedizin Berlin, Berlin; ⁵Department of Pulmonary Diseases, Amsterdam UMC, VU University Medical Center, Amsterdam Cardiovascular Sciences (ACS), Amsterdam, NL; ⁶Department of Intensive Care Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, NL; ⁷Flow Cytometry Core Facility, German Rheumatism Research Centre Berlin (DRFZ), Berlin; ⁸Labor für Lungenkreislaufforschung, Nachwuchsgruppe Immunodynamik, Institut für Physiologie, Charité - Universitätsmedizin Berlin, Berlin;
Cystic fibrosis transmembrane conductance regulator (CFTR) is a Cl- channel and ABC transporter; its mutations cause the clinical picture of cystic fibrosis (CF). Of late, CFTR has also emerged as an important regulator of platelet function, as CFTR dysfunction causes agonist-induced platelet hyperactivation. These findings are reminiscent of platelets from SARS-CoV-2 infected patients since thromboembolic complications represent hallmarks of severe COVID-19 that may critically contribute to morbidity and mortality. CFTR modulators have recently been introduced as a treatment for patients with various CFTR mutations, but have also been reported by us and others to enhance channel function of wild type CFTR. We therefore postulated that CFTR modulators may exert anti-coagulant effects on platelets of COVID-19 patients. We recruited 36 COVID-19 patients with moderate, and 34 COVID-19 patients with severe disease course (all w/o anti-platelet drugs), and 38 healthy donors (HDs). To determine the activation status of platelets, changes in surface expression of CD62p and CD63 upon pre-treatment with vehicle or the CFTR potentiator ivacaftor were analyzed by flow cytometry. Platelets were activated by the platelet agonists adenosine diphosphate (ADP) or thrombin receptor activating protein-6 (TRAP6), and analyzed for Ca2+-mobilization by FACS, by impedance aggregometry, and by a microfluidic flow assay assessing platelet adhesion after pre-treatment with or without ivacaftor. In line with our hypothesis, we observed significant reductions in ADP- or TRAP6-induced CD62p/CD63 expression, Ca2+-mobilization, aggregation, and adhesion of platelets from HDs by pre- treatment with ivacaftor. In blood from COVID-19 patients, platelet activation correlates with disease severity, as demonstrated by a 5-fold and 8-fold increase in the proportion of CD62p+ platelets from patients with moderate and severe disease, respectively, relative to HDs. Similarly, the proportion of CD63+ platelets in patients with severe COVID-19 was 2-fold higher than in HDs. Retrospective analysis of clinical data from a total of 4,050 CF patients with COVID-19 receiving single or combination therapy of ivacaftor, lumacaftor, tezacaftor, or elexacaftor in comparison to an untreated cohort revealed that CF therapy reduced the relative risk to suffer thromboembolism-associated cardiovascular events such as heart attack or deep vein thrombosis by 50.0% or 61.1%, respectively, suggesting an anti-thrombotic effect of CFTR modulators in CF COVID-19 patients. In line with this observation, ex vivo pre-treatment of platelets from acute COVID-19 patients with ivacaftor reduced Ca2+ mobilization, adhesion, and aggregation of platelets. Our results demonstrate an anticoagulant effect of CFTR potentiators on platelets from HDs and severe COVID-19 patients and thus, suggest CFTR potentiators as a promising strategy to reduce the risk of thrombotic events in the clinical management of COVID-19.
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