title: Hypercholesterolemia blunts forearm vasorelaxation and enhances the pressor response during acute systemic hypoxia.
abstract: OBJECTIVE
  During hypoxia, active substances released by the endothelium play a key role in the cardiovascular and respiratory responses elicited to optimize oxygen delivery. As hypercholesterolemia is a major cause of endothelial dysfunction, it may interfere with these responses.
  
  
  RESULTS
  We studied cardiovascular and ventilatory responses to acute systemic hypoxia in 14 patients with hypercholesterolemia (HC) and 13 control (CO) subjects. Oxygen saturation decreased similarly in both groups. Diastolic blood pressure increased only in the HC group (P=0.0002) and, despite systolic blood pressure increases both in the HC group, 140+/-4 (95% confidence interval [CI],131 to 149 mm Hg) to 154+/-4 mm Hg (95% CI,145 to 164 mm Hg), and in the CO group, 133+/-3 (95% CI,126 to 140 mm Hg) to 140+/-4 mm Hg (95% CI,132 to 148 mm Hg), the HC group showed an enhanced pressor response (P=0.03, group comparison). Both groups had increased forearm blood flow, but the decrease in forearm vascular resistance in the CO group, 40+/-5 (95% CI, 30 to 51 UR) to 31+/-4 UR (95% CI,23 to 39 UR) (P=0.0001) was not seen in the HC group, 29+/-3 (95% CI, 22 to 37 UR) to 26+/-3 UR (95% CI, 20 to 33 UR), (P=0.03, group comparison).
  
  
  CONCLUSIONS
  Hypercholesterolemic patients demonstrate a hyperreactive pressor response and absence of forearm vasodilation during acute systemic hypoxia.
authors.affiliation: The Hypertension Unit, Heart Institute (InCor), University of São Paulo Medical School, Brazil. jose.barreto@incor.usp.br
authors.forename: José Augusto S
authors.initials: JA
authors.lastname: Barreto-Filho
authors.forename: Fernanda Marciano
authors.initials: FM
authors.lastname: Consolim-Colombo
authors.forename: Grazia Maria
authors.initials: GM
authors.lastname: Guerra-Riccio
authors.forename: Raul D
authors.initials: RD
authors.lastname: Santos
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Chacra
authors.forename: Heno Ferreira
authors.initials: HF
authors.lastname: Lopes
authors.forename: Sandra H
authors.initials: SH
authors.lastname: Teixeira
authors.forename: Tânia
authors.initials: T
authors.lastname: Martinez
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: Krieger
authors.forename: Eduardo Moacyr
authors.initials: EM
authors.lastname: Krieger
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism; D005260:Female; D005542:Forearm / Q000098:blood supply* / Q000503:physiopathology; D006801:Humans; D006937:Hypercholesterolemia / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011311:Pressoreceptors / Q000378:metabolism*; D012039:Regional Blood Flow / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide