Microparticle subpopulations are increased in preeclampsia: Possible involvement in vascular dysfunction?

OBJECTIVE: The purpose of this study was to investigate the cellular origin and numbers of circulating microparticles in normal pregnancy and preeclampsia. STUDY DESIGN: Plasma samples from 10 women with preeclampsia, from 10 normal pregnant women, and from 10 nonpregnant women matched for age and gestation, were analyzed by flow cytometry. RESULTS: The total number of circulating microparticles was unaltered in pregnancy and preeclampsia. The largest portion of microparticles was derived from platelets in all groups. T-suppressor cell microparticle numbers were decreased in normal pregnancy (P=.04). In preeclampsia T-suppressor, T-helper cell, and granulocyte microparticle numbers were increased (P = 008,.008, and .03, respectively). Elastase concentrations were increased in preeclampsia (P = .02) and correlated with granulocyte microparticle numbers (P = .006). Elastase concentrations correlated with systolic and diastolic blood pressure (P = .001 and .003, respectively), and granulocyte microparticle numbers correlated with systolic blood pressure (P = .05). CONCLUSION: Numbers of T-cell and granulocyte microparticles are increased in preeclampsia. Whether these altered microparticle numbers cause vascular dysfunction in preeclampsia or are a consequence of the disease remains to be established.