title: An intense and short-lasting burst of neutrophil activation differentiates early acute myocardial infarction from systemic inflammatory syndromes.
abstract: BACKGROUND
  Neutrophils are involved in thrombus formation. We investigated whether specific features of neutrophil activation characterize patients with acute coronary syndromes (ACS) compared to stable angina and to systemic inflammatory diseases.
  
  
  RESULTS
  The myeloperoxidase (MPO) content of circulating neutrophils was determined by flow cytometry in 330 subjects: 69 consecutive patients with acute coronary syndromes (ACS), 69 with chronic stable angina (CSA), 50 with inflammation due to either non-infectious (acute bone fracture), infectious (sepsis) or autoimmune diseases (small and large vessel systemic vasculitis, rheumatoid arthritis). Four patients have also been studied before and after sterile acute injury of the myocardium (septal alcoholization). One hundred thirty-eight healthy donors were studied in parallel. Neutrophils with normal MPO content were 96% in controls, >92% in patients undergoing septal alcoholization, 91% in CSA patients, but only 35 and 30% in unstable angina and AMI (STEMI and NSTEMI) patients, compared to 80%, 75% and 2% of patients with giant cell arteritis, acute bone fracture and severe sepsis. In addition, in 32/33 STEMI and 9/21 NSTEMI patients respectively, 20% and 12% of neutrophils had complete MPO depletion during the first 4 hours after the onset of symptoms, a feature not observed in any other group of patients. MPO depletion was associated with platelet activation, indicated by P-selectin expression, activation and transactivation of leukocyte β2-integrins and formation of platelet neutrophil and -monocyte aggregates. The injection of activated platelets in mice produced transient, P-selectin dependent, complete MPO depletion in about 50% of neutrophils.
  
  
  CONCLUSIONS
  ACS are characterized by intense neutrophil activation, like other systemic inflammatory syndromes. In the very early phase of acute myocardial infarction only a subpopulation of neutrophils is massively activated, possibly via platelet-P selectin interactions. This paroxysmal activation could contribute to occlusive thrombosis.
authors: Università Vita-Salute San Raffaele and San Raffaele Scientific Institute, Milano, Italy. maugeri.norma@hsr.it
authors: Norma
authors: N
authors: Maugeri
authors: Patrizia
authors: P
authors: Rovere-Querini
authors: Virgilio
authors: V
authors: Evangelista
authors: Cosmo
authors: C
authors: Godino
authors: Monica
authors: M
authors: Demetrio
authors: Mattia
authors: M
authors: Baldini
authors: Filippo
authors: F
authors: Figini
authors: Giovanni
authors: G
authors: Coppi
authors: Massimo
authors: M
authors: Slavich
authors: Marina
authors: M
authors: Camera
authors: Antonio
authors: A
authors: Bartorelli
authors: Giancarlo
authors: G
authors: Marenzi
authors: Lara
authors: L
authors: Campana
authors: Elena
authors: E
authors: Baldissera
authors: Maria Grazia
authors: MG
authors: Sabbadini
authors: Domenico
authors: D
authors: Cianflone
authors: Elena
authors: E
authors: Tremoli
authors: Armando
authors: A
authors: D'Angelo
authors: Angelo A
authors: AA
authors: Manfredi
authors: Attilio
authors: A
authors: Maseri
mesh_terms: D000328:Adult; D000368:Aged; D000789:Angina, Unstable / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology* / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D009203:Myocardial Infarction / Q000276:immunology* / Q000378:metabolism; D018375:Neutrophil Activation / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D019007:P-Selectin / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism
chemical_list: D019007:P-Selectin; D009195:Peroxidase