Online now: Yacine Boulaftali, Steffen Massberg and I summarized recent key insights into the role of platelets in vascular inflammation:
journals.lww.com/co-hematolog...

11/x We then asked if this also applies to human platelet concentrates stored in vitro. Indeed, apheresis platelets also showed a decrease in hemostatic potential and an increase in procoagulant function and neutrophil aggregate formation.

10/x Importantly, these mice showed increased pulmonary inflammation with elevated cytokines and an increased leukocyte recruitment, which could be reversed through platelet rejuvenation. This showcases that aged platelets can indeed exacerbate inflammation.

8/x As expected, young platelets showed upregulation of ribosomal proteins. The aged cohort showed upregulation of immune pathways, correlating well with our in vivo and in vitro results.

7/x Using the PF4Cre-iDTR mouse, we created platelet cohorts of similar age using Diphtheria toxin application in this mouse line, and performed shotgun proteomics. This revealed clear separation of aged and young platelets with regards to proteome.

6/x We then asked if this translates to in vivo differences. Indeed, in thrombosis, more young platelets were recruited, whereas in an assay of lung inflammation, there was higher relative recruitment of aged platelets.

5/x ..and formed more platelet neutrophil aggregates upon co-incubation, which could be blocked by antibodies against CD40. These platelets were also better at killing S. Aureus bacteria in vitro.

4/x Interestingly, though, aged platelets (3-4 days old) showed increased expression of immune related receptors including CD40L and CLEC-2. They were more likely to become procoagulant,

3/x Here, using an antibody-based fate mapping approach, we were able to directly demonstrate that young platelets (0-12hrs old) are better at adhesion and clot formation in vitro. This fits well with translational data implicating young, reticulated platelets for example in myocardial infarction.

1/x Online now: Our work on platelet aging and inflammation in @bloodjournal.bsky.social led by superstar PhD student Afra Anjum: ashpublications.org/blood/articl...

Arterial thrombosis - studying platelet recruitment at the single cell level in vivo

It was an immense pleasure to host our 2nd #immunothrombosis Symposium @LMU Munich
together with Konstantin Stark. Talks and discussions were outstanding, and new ideas & perspectives made the meeting really special!