Avaliação de aspectos da função plaquetária e do sistema do complemento na hipertensão gestacional

Abstract

Introduction:Hypertensive disorders are one of the most frequent complications of pregnancy, being responsible for a high rate of maternal-fetal death. Preeclampsia Syndrome (PES) is characterized by elevated blood pressure and pathological proteinuria after the 20th week of gestation, and may have outcomes such as HELLP syndrome, eclampsia, preterm pregnancy and restricted intrauterine growth. Imbalance in hemostatic mechanisms can occur during pregnancy with a tendency for hypercoagulability and increased thrombosis risk. In pregnant women with hypertensive disorders, especially in preeclampsia (PE), this risk is increased. There is a suggestion of increased thrombin generation, activation of the complement system and release of antiangiogenic factors. Pregnant women with hypertensive disorder, especially preeclampsia, show alterations in platelet indexes, mean platelet volume (MPV), immature platelet fraction (IPF), thrombin generation and soluble membrane attack complex(sC5b9). IPF has been suggested as a sensitive index for monitoring changes in platelet production and destruction. Objectives: To evaluate IPF, MPV and C5b9 in patients diagnosed with a gestational hypertensive disorders (GHD). Material and method: A cross-sectional study was conducted in pregnant women with normotensive pregnancy (NP), preeclampsia syndrome (PES) or non-proteinuric hypertensive pregnancy (nPHP). Following ethical approval and written informed consent, samples were collected. Platelet count and indexes were measured by fluorescent flow cytometry by automated counters XE-5000 and XN-3000 (Sysmex Corporation, Roche, Kobe, Japan). Plasma and serum samples were frozen at -80°C for laterdetermination of sC5b9 by ELISA. Results: A total of 111 pregnant women were included and divided into three groups: PES, nPHP and NP with 47,30 and 34 women, respectively. Results are presented in the following sequence: PES, nPHP and NP. MVP was 12.18±1.6, 11.5±1.2 and 10.8±0.99 fL (P<0.001);IPF was 7.4 (1.9-21.8), 6.8(2.4-17) and 4.9(1.3-9.7)% (P=0.004); platelets counts were 199127±52864, 225827±80728 and 240323±54321 /uL (P=0.012). sC5b9 was 1040 (706-1433), 1221(849-1771) and 1471(1085-1986) ng/mL (P=0.023). Conclusion: MPV and IPF are increased and platelet count is decreased in patients with SPE compared to controls. sC5b9 was increased in controls in comparison with SPE. Controls and HGsP group had similar sC5b9 levels. There was no association between platelet indexes and sC5b9. MPV and IPF are measurements can be obtained quickly, have low-cost and are easily accessible in hospitals that use advanced technology for blood counts. It is suggested that these markers could be used in daily routine as an additional tool in the management of pregnant women. More studies are needed to understand the activation of the complement system in pregnancy and PES and the interaction between platelets and the complement pathway.