title: Increased levels of circulating platelet-derived microparticles in psoriasis: Possible implications for the associated cardiovascular risk.
abstract: OBJECTIVE
  To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.
  
  
  METHODS
  Forty psoriatic patients without cardiovascular disease, and 12 healthy controls were subjected to measurement of baseline platelet CD62P, CD63 and CD42b expression, platelet-leukocyte complexes,i.e., platelet-monocyte complexes (PMC), platelet-neutrophil complexes (PNC) and platelet-lymphocyte complexes, and concentrations of platelet-derived microparticles (PMPs) using flow cytometry. Both larger-size (0.5-0.9 μm) and smaller-size (< 0.5 μm) PMPs were determined. Serum interleukin (IL)-12 and IL-17 levels were also measured by enzyme-linked immunosorbent assay. The severity of psoriasis was evaluated by the Psoriasis Area Severity Index (PASI).
  
  
  RESULTS
  PMP concentrations were significantly higher in psoriasis patients than controls [mean ± standard error of mean (SEM): 22 ± 5/μLvs11 ± 6/μL;P =0.018), for both smaller-size (10 ± 2/μLvs4 ± 2/μL;P =0.033) and larger-size (12 ± 3/μLvs6 ± 4/μL;P =0.014) PMPs. Platelet CD62P, CD63 and CD42b expression and circulating PMC and PNC were similar between the two groups. Lower circulating PLC were observed in psoriasis patients compared to controls (mean ± SEM: 16% ± 3%vs23% ± 6%;P =0.047). Larger-size PMPs were related with IL-12 levels (P <0.001) and smaller-size PMPs with both IL-12 and IL-17 levels (P <0.001). Total PMPs also correlated with IL-12 (P <0.001). CD63 expression was positively correlated with both IL-12 and IL-17 (P <0.05). Increased PASI score was associated with increased levels of larger-size PMPs (r = 0.45;P= 0.011) and increased CD63 expression (r = 0.47;P <0.01).
  
  
  CONCLUSIONS
  PMPs, known to be predictive of cardiovascular outcomes, are increased in psoriasis patients, and associated with high inflammatory disease burden. Enhanced platelet activation may be the missing link leading to cardiovascular events in psoriatic patients.
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Papadavid
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Konstantina
authors.initials: K
authors.lastname: Diamanti
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Aris
authors.initials: A
authors.lastname: Spathis
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Varoudi
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Andreadou
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Kostas
authors.initials: K
authors.lastname: Gravanis
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Kostas
authors.initials: K
authors.lastname: Theodoropoulos
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Petros
authors.initials: P
authors.lastname: Karakitsos
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: John
authors.initials: J
authors.lastname: Lekakis
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Rigopoulos
authors.affiliation: Evangelia Papadavid, Konstantina Diamanti, Kostas Theodoropoulos, Dimitrios Rigopoulos, 2 Department of Dermatology and Venereology, University of Athens Medical School, Attikon Hospital, 12462 Athens, Greece.
authors.forename: Ignatios
authors.initials: I
authors.lastname: Ikonomidis
keywords: Atherosclerosis; Inflammation; Platelet activation; Platelet-derived microparticles; Psoriasis