title: Intensified large artery and microvascular response to cold adrenergic stimulation in African blacks.
abstract: BACKGROUND
  Arterial stiffening is more accelerated in blacks than in whites. Whether this is attributed to an enhanced vascular reactivity to environmental stress stimulation remains unknown. We therefore decided to test the hypothesis that cold pressor test (CPT) elicits a greater increase in arterial stiffness and an enhanced sympathetic skin vasoconstriction in African blacks than in whites normotensives.
  
  
  METHODS
  A total of 17 young normotensive African blacks and 17 normotensive whites were recruited. All underwent continuous assessment of blood pressure (BP), heart rate, and carotid-femoral pulse wave velocity (PWVc-f) at rest, during and after hand immersion in iced water (CPT). Concomitantly, skin microvascular blood flow was monitored by laser Doppler flowmetry on the opposite hand.
  
  
  RESULTS
  At baseline, African blacks exhibited higher values of PWVc-f than whites (7.2 +/- 0.3 vs. 6.5 +/- 0.2 m/s, respectively, P = 0.04). During CPT the increases in systolic BP and PWVc-f were greater in African blacks than in whites (systolic BP 17 +/- 2 mm Hg vs. 9 +/- 3 mm Hg, P < 0.001 and PWVc-f 0.62 +/- 0.1 m/s vs. 0.26 +/- 0.1 m/s, P = 0.03, respectively). However, there was no significant difference in the PWVc-f responses among the groups during CPT after adjustment for the increments in mean BP. Finally, CPT induced a more pronounced skin microvascular vasoconstriction in African blacks than in whites (-54.4 +/- 5 % vs. -31.3 +/- 6 %, P < 0.001).
  
  
  CONCLUSIONS
  CPT provokes a more pronounced increase in PWVc-f in normotensive African blacks than in whites, that appears to be due to a greater increase in mean BP. Additionally, African blacks present an intensified skin microvascular response to the CPT as compared to their whites counterparts.
authors.affiliation: Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium. adamopoulos1@gmail.com
authors.forename: Dionysios
authors.initials: D
authors.lastname: Adamopoulos
authors.forename: William
authors.initials: W
authors.lastname: Ngatchou
authors.forename: Daniel
authors.initials: D
authors.lastname: Lemogoum
authors.forename: Christophe
authors.initials: C
authors.lastname: Janssen
authors.forename: Sofia
authors.initials: S
authors.lastname: Beloka
authors.forename: Oliver
authors.initials: O
authors.lastname: Lheureux
authors.forename: Patricia
authors.initials: P
authors.lastname: Kayembe
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Argacha
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Degaute
authors.forename: Philippe
authors.initials: P
authors.lastname: van de Borne
mesh_terms: D000328:Adult; D000349:Africa / Q000208:ethnology; D044383:Black People; D001794:Blood Pressure / Q000502:physiology*; D002339:Carotid Arteries / Q000502:physiology; D003080:Cold Temperature; D004548:Elasticity; D005263:Femoral Artery / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D011674:Pulse; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*; D014661:Vasoconstriction; D044465:White People