RESUMEN
The epidemiological studies confirm an increased risk of cardiovascular disease in multiple sclerosis, especially prothrombotic events directly associated with abnormal platelet activity. The aim of our study was to investigate the level of blood platelet activation in the circulation of patients with chronic phase of multiple sclerosis (SP MS) and their reactivity in response to typical platelets' physiological agonists. We examined 85 SP MS patients diagnosed according to the revised McDonald's criteria and 50 healthy volunteers as a control group. The platelet activation and reactivity were assessed using flow cytometry analysis of the following: P-selectin expression (CD62P), activation of GP IIb/IIIa complex (PAC-1 binding), and formation of platelet microparticles (PMPs) and platelet aggregates (PA) in agonist-stimulated (ADP, collagen) and unstimulated whole blood samples. Furthermore, we measured the level of soluble P-selectin (sP-selectin) in plasma using ELISA method, to evaluate the in vivo level of platelet activation, both in healthy and SP MS subjects. We found a statistically significant increase in P-selectin expression, GP IIb/IIIa activation, and formation of PMPs and PA, as well as in unstimulated and agonist-stimulated (ADP, collagen) platelets in whole blood samples from patients with SP MS in comparison to the control group. We also determined the higher sP-selectin level in plasma of SP MS subjects than in the control group. Based on the obtained results, we might conclude that during the course of SP MS platelets are chronically activated and display hyperreactivity to physiological agonists, such as ADP or collagen.
Asunto(s)
Plaquetas/metabolismo , Micropartículas Derivadas de Células/metabolismo , Citometría de Flujo , Esclerosis Múltiple/sangre , Activación Plaquetaria , Adulto , Plaquetas/patología , Micropartículas Derivadas de Células/patología , Fosfatasa 2 de Especificidad Dual/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/patología , Selectina-P/sangre , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismoRESUMEN
BACKGROUND: The FYB gene encodes adhesion and degranulation-promoting adaptor protein (ADAP), a hematopoietic-specific protein involved in platelet activation, cell motility and proliferation, and integrin-mediated cell adhesion. No ADAP-related diseases have been described in humans, but ADAP-deficient mice have mild thrombocytopenia and increased rebleeding from tail wounds. PATIENTS AND METHODS: We studied a previously reported family of five children from two consanguineous sibships of Arab Christian descent affected with a novel autosomal recessive bleeding disorder with small-platelet thrombocytopenia. Homozygosity mapping and exome sequencing were used to identify the genetic lesion causing the disease phenotype on chromosome 5. Bone-marrow morphology and platelet function were analyzed. Platelets were characterized by scanning electron microscopy. RESULTS: We identified a homozygous deleterious nonsense mutation, c.393G>A, in FYB. A reduced percentage of mature megakaryocytes was found in the bone marrow. Patients' platelets showed increased basal expression of P-selectin and PAC-1, and reduced increments of activation markers after stimulation with ADP, as detected by flow cytometry; they also showed reduced pseudopodium formation and the presence of trapped platelets between the fibrin fibers after thrombin addition, as observed on scanning electron microscopy. CONCLUSIONS: This is the first report of a disease caused by an FYB defect in humans, manifested by remarkable small-platelet thrombocytopenia and a significant bleeding tendency. The described phenotype shows ADAP to be important for normal platelet production, morphologic changes, and function. It is suggested that mutation analysis of this gene be included in the diagnosis of inherited thrombocytopenia.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Plaquetas/ultraestructura , Codón sin Sentido , Hemorragia/genética , Hemostasis/genética , Trombocitopenia/genética , Árabes/genética , Plaquetas/metabolismo , Tamaño de la Célula , Análisis Mutacional de ADN , Fosfatasa 2 de Especificidad Dual/sangre , Exoma , Marcadores Genéticos , Predisposición Genética a la Enfermedad , Hemorragia/sangre , Hemorragia/diagnóstico , Hemorragia/etnología , Heterocigoto , Homocigoto , Humanos , Israel/epidemiología , Microscopía Electrónica de Rastreo , Selectina-P/sangre , Linaje , Fenotipo , Pruebas de Función Plaquetaria , Valor Predictivo de las Pruebas , Factores de Riesgo , Trombocitopenia/sangre , Trombocitopenia/diagnóstico , Trombocitopenia/etnologíaRESUMEN
BACKGROUND: Changes in platelet reactivity during 2009 influenza A(H1N1) (A[H1N1]) have not been characterized. METHODS: We prospectively examined platelet activation and cytokine responses in patients with A(H1N1) (n = 20), matched patients with bacterial pneumonia (n = 15), and nonhospitalized, healthy control subjects (n = 10). RESULTS: Platelet-monocyte aggregation was higher in patients with A(H1N1) (21.4% ± 4.7%) compared with patients with pneumonia (10.9% ± 3.7%) and control subjects (8.1% ± 4.5%, P < .05). Similarly, PAC-1 (antibody that binds to the active conformation of integrin α(IIb)ß(3)) binding to platelets is increased in patients with A(H1N1) (9.5% ± 4.7%) compared with patients with pneumonia (1.0% ± 0.7%) and healthy subjects (0.61% ± 0.15%, P < .10). PAC-1 binding was twofold higher in patients with A(H1N1) with shock vs those without shock. IL-6 levels were elevated in patients with A(H1N1), indicating systemic inflammation consistent with activation of circulating platelets. CONCLUSIONS: These findings, derived from a small but documented cohort of patients, demonstrate that platelet activation responses during A(H1N1) are enhanced-exceeding responses in patients with bacterial pneumonia-and provide new evidence that platelets may contribute to inflammatory responses during A(H1N1).
Asunto(s)
Enfermedad Crítica , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/sangre , Activación Plaquetaria , APACHE , Adulto , Análisis de Varianza , Estudios de Casos y Controles , Distribución de Chi-Cuadrado , Comorbilidad , Fosfatasa 2 de Especificidad Dual/sangre , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Humanos , Gripe Humana/mortalidad , Gripe Humana/virología , Interleucina-6/sangre , Tiempo de Internación/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Necrosis Tumoral alfa/sangreRESUMEN
BACKGROUND AND OBJECTIVES: EMMPRIN (CD147) is a matrix metalloproteinase inducer present on leukocytes and recently identified on platelets in vitro. We examined platelet CD147 expression in vivo and in correlation with markers of platelet activation and coronary artery disease (CAD). PATIENTS/METHODS: This prospective observational study involved 70 subjects (55 patients with CAD and 15 controls). Platelet CD62P expression, PAC-1 expression, platelet-leukocyte aggregates and CD147 (both platelet and leukocyte) expression were assessed by flow cytometry, and soluble CD62P expression was assessed by enzyme-linked immunosorbent assay. A full blood count and high-sensitivity C-reactive protein test were performed. RESULTS: CD147 was expressed on 20.45% +/- 1.63% (mean +/- standard error of the mean) of circulating platelets, whereas CD62P and PAC-1 were expressed on 0.87% +/- 0.12% and 0.90% +/- 0.27% of platelets, respectively. Platelet CD147 expression correlated with CD62P expression (r = 0.359, P = 0.002), PAC-1 expression (r = 0.428, P < 0.001), leukocyte CD147 expression (monocyte, r = 0.416, P = 0.001; granulocyte, r = 0.434, P < 0.001), C-reactive protein level and neutrophil/lymphocyte ratio (NLR). CAD patients had significantly higher CD147 mean fluorescence intensity than controls on circulating platelets (2.41 +/- 0.14 vs. 2.87 +/- 0.09, P = 0.014), monocytes (8.57 +/- 1.20 vs. 12.3 +/- 0.57, P = 0.006) and granulocytes (4.30 +/- 0.65 vs. 6.50 +/- 0.34, P = 0.005). Age adjustment eliminated the association between platelet CD147 expression and CAD, but the association between leukocyte CD147 expression and CAD persisted. According to multivariate analysis, the independent predictors of platelet CD147 expression were monocyte CD147 expression, NLR and age. CONCLUSIONS: Platelet CD147 expression is evident in vivo and correlates moderately with traditional platelet activation markers and leukocyte CD147 expression. Platelet CD147 expression shows a stronger association with age, and leukocyte CD147 expression a stronger association with clinical CAD, suggesting differences in the regulation of platelet and leukocyte CD147 expression in vivo.