Elevated platelet P-selectin expression and platelet activation in high risk patients with uncontrolled severe hypertension.
BACKGROUND
Uncontrolled severe hypertension is associated with alarming rates of cardiovascular events but the mechanisms of vascular injury are not well understood. Recent investigative interest has focused on platelet activation and platelet P-selectin (CD62P) as direct mediators of vascular inflammation and injury. We investigated the association of extreme blood pressure (BP) elevation with platelet P-selectin and fibrinolytic markers in high risk patients with severe hypertension.


METHODS
Cross-sectional comparison of platelet CD62, tissue plasminogen activator antigen (tPA), and plasminogen activator inhibitor-1 activity (PAI-1) among 3 BP groups: untreated severely hypertensive patients (SHT; n=18), untreated mildly hypertensive patients (MHT; n=19), and normotensive controls (NT; n=16).


RESULTS
Platelet CD62 was greatest in SHT (p=0.00008) and showed a strong correlation with both systolic (p=0.0002, r=0.52) and diastolic (p=0.0003, r=0.52) BP. tPA was greater in SHT than MHT or NT (ANOVA; p=0.02) and correlated with diastolic BP but not SBP. PAI-1 did not correlate with either SBP or DBP but was related to body mass index, diabetes, and dyslipidemia.


CONCLUSIONS
Platelet CD62 demonstrated a strong and graded association with both systolic and diastolic BP that persisted in the presence of multiple concomitant risk factors. The association of BP with CD62P was stronger than with either PAI-1 or tPA-Ag. Platelet activation and platelet CD62 increase in a BP-dependent manner and this relationship persists at extreme levels of BP. Platelet activation and platelet CD62 may participate in the accelerated target organ injury observed in high risk patients with severe hypertension.
Preston
Richard A
RA
Division of Clinical Pharmacology Clinical Research Center, Department of Medicine, Leonard M. Miller School of Medicine, University of Miami, Miami, FL 33136, United States. rpreston@med.miami.edu <rpreston@med.miami.edu>
Coffey
James O
JO
Materson
Barry J
BJ
Ledford
Marlies
M
Alonso
Alberto B
AB
D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000150:complications / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D015539:Platelet Activation / Q000502:physiology*; D012307:Risk Factors; D012720:Severity of Illness Index; D010959:Tissue Plasminogen Activator / Q000097:blood*
D019007:P-Selectin; D017395:Plasminogen Activator Inhibitor 1; D010959:Tissue Plasminogen Activator