title: Putative endothelial progenitor cells are associated with flow-mediated dilation in refractory hypertensives.
abstract: BACKGROUND
  Hypertension has been related to endothelial dysfunction. Patients with refractory hypertension (RH) have a reduced number of endothelial progenitor cells (EPCs).
  
  
  OBJECTIVE
  To evaluate if blood EPC levels relate to endothelium-dependent vasodilation (ED-VD) in RH.
  
  
  METHODS
  We analyzed 29 RH confirmed by 24-h ambulatory blood pressure monitoring and assessed complete clinical and laboratory evaluation. EPCs were isolated from peripheral mononuclear cells (MNC) by flow cytometry. ED-VD was determined measuring flow-mediated dilation (FMD) by venous occlusion plethysmography. Results. Circulating EPCs/10(5) MNC (median [Q1-Q3]): 23.0 [4.5-53.8]. FMD (median [Q1-Q3]): 211.7 [79.5-365.8]%. Significant correlations with log-FMD: EPCs (r = 0.469; p = 0.018) and homocysteine (r = -0.414; p = 0.045). There was no collinearity between EPCs and homocysteine. FMD did not correlate with age, gender, office BP, 24-h systolic blood pressure or 24-h diastolic blood pressure, laboratory parameters, C-reactive-protein, left ventricular-mass index, dyslipidaemia, smoking habit and statin or angiotensin system blockers treatment. Multiple linear regression analysis showed that after age-adjustment, EPC (p = 0.027) and homocysteine (p = 0.004) were the only variables that predicted FMD (R = 0.740). After dividing patients according to EPC number, patients in the lower tertile showed a significantly reduced FMD compared with those in the group of the two upper tertiles of EPC: log-FMD (mean+/-SD): 4.7+/-0.9 vs 5.6+/-0.8, respectively (p = 0.031).
  
  
  CONCLUSIONS
  ED-VD independently correlates with circulating EPCs in RH. Homocysteine is also an independent predictor of lower FMD in such patients.
authors.affiliation: Hypertension Unit, Nephrology Department, Hospital Universitari del Mar, Universitat Autonoma de Barcelona, Medicine Department, Barcelona, Spain. aoliveras@imas.imim.es
authors.forename: Anna
authors.initials: A
authors.lastname: Oliveras
authors.forename: Alejandro
authors.initials: A
authors.lastname: de la Sierra
authors.forename: Ofelia M
authors.initials: OM
authors.lastname: Martínez-Estrada
authors.forename: María
authors.initials: M
authors.lastname: Larrousse
authors.forename: Susana
authors.initials: S
authors.lastname: Vázquez
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Soler
authors.forename: Mercedes
authors.initials: M
authors.lastname: Zuasti
authors.forename: Joan S
authors.initials: JS
authors.lastname: Vila
authors.forename: Manuel
authors.initials: M
authors.lastname: Reina
authors.forename: Alex
authors.initials: A
authors.lastname: Roca-Cusachs
authors.forename: Josep
authors.initials: J
authors.lastname: Lloveras
mesh_terms: D000328:Adult; D002452:Cell Count; D002469:Cell Separation; D004108:Dilatation, Pathologic / Q000175:diagnosis* / Q000473:pathology; D042783:Endothelial Cells / Q000473:pathology*; D005434:Flow Cytometry; D006710:Homocysteine / Q000097:blood; D006801:Humans; D006973:Hypertension / Q000473:pathology*; D008875:Middle Aged; D011237:Predictive Value of Tests; D012044:Regression Analysis; D013234:Stem Cells / Q000473:pathology*; D014664:Vasodilation
chemical_list: D006710:Homocysteine