Putative endothelial progenitor cells are associated with flow-mediated dilation in refractory hypertensives.
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.
Oliveras
Anna
A
Hypertension Unit, Nephrology Department, Hospital Universitari del Mar, Universitat Autonoma de Barcelona, Medicine Department, Barcelona, Spain. aoliveras@imas.imim.es
de la Sierra
Alejandro
A
Martínez-Estrada
Ofelia M
OM
Larrousse
María
M
Vázquez
Susana
S
Soler
Maria José
MJ
Zuasti
Mercedes
M
Vila
Joan S
JS
Reina
Manuel
M
Roca-Cusachs
Alex
A
Lloveras
Josep
J
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
D006710:Homocysteine