title: Evaluation and validation of a method for determining platelet catecholamine in patients with obstructive sleep apnea and arterial hypertension.
abstract: BACKGROUND
  Measurements of plasma and urinary catecholamine are susceptible to confounding factors that influence the results, complicating the interpretation of sympathetic nervous system (SNS) activity in the Obstructive sleep apnea (OSA) and arterial hypertension (HYP) conditions.
  
  
  OBJECTIVE
  In this study, we validated a test for platelet catecholamine and compared the catecholamine levels (adrenaline and noradrenaline) in urine, plasma and platelets in patients with OSA and HYP compared with controls.
  
  
  METHODS
  In the validation, 30 healthy, nonsmoking volunteers who were not currently undergoing treatment or medication were selected as the control group. One hundred fifty-four individuals (114 OSA, 40 non-OSA) were consecutively selected from the outpatient clinic of the Sleep Institute and underwent clinical, polysomnographic and laboratory evaluation, including the urinary, plasma and platelet levels of adrenaline (AD) and noradrenaline (NA). Patients were then allocated to groups according to the presence of OSA and/or hypertension.
  
  
  RESULTS
  A logistic regression model, controlled for age and BMI, showed that urinary AD and urinary NA were risk factors in the OSA+HYP group and the HYP group; however, the model showed higher levels of platelet NA for OSA without HYP. After 1 year of CPAP (continuous upper airway pressure) treatment, patients (n = 9) presented lower levels of urinary NA (p = 0.04) and platelet NA (p = 0.05).
  
  
  CONCLUSIONS
  Urinary NA and AD levels were significantly associated with the condition of hypertension with and without OSA, whereas platelet NA with OSA without comorbidity. These findings suggest that platelet catecholamine levels might reflect nocturnal sympathetic activation in OSA patients without hypertension.
authors.affiliation: Psychobiology Department of Universidade Federal de São Paulo, Sao Paulo, SP, Brazil.
authors.forename: Marcia C
authors.initials: MC
authors.lastname: Feres
authors.affiliation: Cardiology Department of Universidade Federal de São Paulo, São Paulo, SP, Brazil.
authors.forename: Fatima D
authors.initials: FD
authors.lastname: Cintra
authors.affiliation: Psychobiology Department of Universidade Federal de São Paulo, Sao Paulo, SP, Brazil.
authors.forename: Camila F
authors.initials: CF
authors.lastname: Rizzi
authors.affiliation: Psychobiology Department of Universidade Federal de São Paulo, Sao Paulo, SP, Brazil.
authors.forename: Luciane
authors.initials: L
authors.lastname: Mello-Fujita
authors.affiliation: Psychobiology Department of Universidade Federal de São Paulo, Sao Paulo, SP, Brazil.
authors.forename: Altay A
authors.initials: AA
authors.lastname: Lino de Souza
authors.affiliation: Psychobiology Department of Universidade Federal de São Paulo, Sao Paulo, SP, Brazil; Associação Fundo de Incentivo a Pesquisa - AFIP- São Paulo, São Paulo, SP, Brazil.
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.affiliation: Psychobiology Department of Universidade Federal de São Paulo, Sao Paulo, SP, Brazil.
authors.forename: Dalva
authors.initials: D
authors.lastname: Poyares
mesh_terms: D000293:Adolescent; D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods*; D001792:Blood Platelets / Q000737:chemistry*; D002395:Catecholamines / Q000097:blood*; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000150:complications* / Q000628:therapy; D055815:Young Adult
chemical_list: D002395:Catecholamines