title: Platelet activation in heart transplant recipients.
abstract: An inappropriate and persistent immune activation has been suggested to contribute to long-term mortality and morbidity after heart transplantation. Several lines of evidence suggest that platelets do not only promote thrombus formation, but also act as inflammatory cells. In the present study, we investigated if long-time survivors of heart transplantation (mean time since transplantation 6.5 yr) were characterized by enhanced platelet activation as assessed by different experimental approaches. Our main findings when comparing heart transplant recipients (n = 52) and age- and sex-matched healthy controls (n = 38) were: (i) platelets from heart transplant recipients showed enhanced expression of both P-selectin and CD63 as assessed by flow cytometry; (ii) platelets from these patients also contained significantly increased levels of soluble CD40 ligand and tended to release higher levels of this cytokine upon SFLLRN stimulation as assessed by enzyme immunoassay; (iii) heart transplant recipients had increased levels of soluble P-selectin in platelet-free plasma; and (iv) the enhanced platelet activation after heart transplantation was most pronounced in those with concomitant hypertension. These findings suggest that long-term survivors of heart transplantation are characterized by enhanced activation of platelets, possibly contributing to the persistent immune activation and clinical complications in these patients.
authors.affiliation: Department of Cardiology, Rikshospitalet, University of Oslo, Oslo, Norway. aina.hognestad@klinmed.uio.no
authors.forename: Aina
authors.initials: A
authors.lastname: Hognestad
authors.forename: Annika
authors.initials: A
authors.lastname: Michelsen
authors.forename: Frank
authors.initials: F
authors.lastname: Brosstad
authors.forename: Jan K
authors.initials: JK
authors.lastname: Damås
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Holm
authors.forename: Svein
authors.initials: S
authors.lastname: Simonsen
authors.forename: John K
authors.initials: JK
authors.lastname: Kjekshus
authors.forename: Pål
authors.initials: P
authors.lastname: Aukrust
authors.forename: Arne K
authors.initials: AK
authors.lastname: Andreassen
mesh_terms: D001792:Blood Platelets / Q000378:metabolism; D023201:CD40 Ligand / Q000097:blood; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood; D010446:Peptide Fragments / Q000494:pharmacology; D015539:Platelet Activation
chemical_list: D019007:P-Selectin; D010446:Peptide Fragments; C082835:thrombin receptor peptide (42-47); D023201:CD40 Ligand