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Preeklampsija spada med hipertenzivne bolezni v nosečnosti, in je definirana s pojavom hipertenzije ter proteinurije po 20. tednu nosečnosti. Prizadene 2‒8 % vseh nosečnic in je kljub napredku na področju diagnostike in zdravljenja še vedno eden glavnih vzrokov za maternalno in perinatalno obolevnost in umrljivost. Raziskave so pokazale, da je preeklampsija zelo verjetno posledica nepravilnega preoblikovanja spiralnih arterij v posteljici, ki ga povzročijo genetski, imunski in okoljski dejavniki v prvem trimesečju nosečnosti. Zmanjšana prekrvljenost in oksigenacijskoreperfuzijske poškodbe posteljice povzročijo njene morfološke spremembe in sproščanje vnetnih, antiangiogenih, imunskih, oksidativnih in vazokonstrikcijskih dejavnikov v materin krvni obtok. Ti nato povzročijo endotelijsko disfunkcijo in druge bolezenske znake, značilne za preeklampsijo. Enako etiopatogenezo lahko opazimo tudi pri zastoju v rasti ploda, ki je pogost, a neobvezen spremljevalec preeklampsije. Namen naše raziskave je bil s pomočjo biokemičnih označevalcev, biofizikalnih parametrov ter njihovimi kombinacijami pojasniti spremembe v delovanju posteljice pri preeklampsiji ter ugotoviti njihovo povezanost z verjetnostjo pojava posameznih in kombiniranih zapletov v nosečnosti. Preveriti smo želeli tri hipoteze, in sicer: 1. Pri preeklampsiji so, ob povišanem augmentacijskem indeksu (AIx) in znižanem indeksu reaktivne hiperemije (RHI), koncentracije placentnega rastnega dejavnika (PlGF) in žilnega endotelijskega rastnega dejavnika (VEGF) znižane, koncentracije topne fms-podobne tirozin kinaze (sFlt-1), inhibina A, placentnega proteina 13 (PP13), topnega endoglina (sEng) in dejavnika tumorske nekroze alfa (TNF-α) pa zvišane. 2. Zvišano razmerje sFlt-1/PlGF je pri nosečnicah s preeklampsijo povezano z zvišanimi koncentracijami PP13, sEng in inhibina A, kar je verjetno posledica nezadostne prekrvljenosti in hipoksije v tkivu posteljice. 3. Zvišano razmerje sFlt-1/PlGF je pri preeklampsiji povezano s povečanim augmentacijskim indeksom in z zvišano stopnjo endotelijske disfunkcije. V ta namen smo primerjali biokemične označevalce in biofizikalne parametre med različnimi skupinami preiskovank z zapleti v nosečnosti in kontrolno skupino žensk z normalno nosečnostjo. V raziskavo smo vključili 36 zdravih nosečnic, 30 nosečnic s preeklampsijo brez zastoja v rasti ploda (PE), 43 nosečnic s preeklampsijo in zastojem v rasti ploda (PE+IUGR) ter 16 nosečnic samo z zastojem v rasti ploda (IUGR). V serumu smo izmerili koncentracije VEGF, PlGF, sFlt-1, sEng, PP13, inhibina A ter TNF-α, v urinu pa koncentracijo proteinov. Z ultrazvokom smo izmerili indekse pretoka krvi, s periferno arterijsko tonometrijo pa indeks reaktivne hiperemije (RHI) in augmentacijski indeks (AIx). V prvem delu raziskave, kjer smo primerjali skupino zdravih nosečnic s skupino s preeklampsijo in zastojem v rasti ploda kot tudi brez, smo zaznali statistično značilno višje vrednosti označevalcev sFlt-1 (p < 0,001), sEng (p < 0,001), inhibina A (p = 0,001), razmerja sFlt-1/PlGF (p < 0,0001), pulzatilnega indeksa (PI) (p < 0,001), indeksa žilnega upora (RI) (p < 0,001) ter prisotnost zarez v obeh materničnih arterijah (p < 0,001). Statistično značilno nižje vrednosti pa smo zaznali pri PlGF (p < 0,001) in razmerju PlGF/(sFlt-1+sEng) (p < 0,0001). Največjo diagnostično natančnost testa za diagnozo PE neglede na zastoj v rasti ploda sta med posameznimi označevalci izkazala sFlt-1 (AUC = 0,92) in sEng (AUC = 0,92) ter kombinacija označevalcev (sFlt-1/PlGF)+PI+RI (AUC = 0,97). Tudi v drugem delu raziskave smo pri primerjavi skupine zdravih nosečnic s skupinami s PE, IUGR in PE+IUGR prišli do podobnih ugotovitev kot v prvem delu raziskave. Poleg tega pa smo pri primerjavi med skupinami preiskovank z zapleti v nosečnosti zaznali statistično značilno višje vrednosti sFlt-1 in sEng v skupini s PE+IUGR v primerjavi s skupino samo z IUGR (p < 0,001 p < 0,001) kot tudi vrednosti PI in RI v skupini z IUGR v primerjavi s skupino s PE (p < 0,001 p < 0,001) ter v skupini s PE+IUGR v primerjavi s skupino samo s PE (p < 0,001 p < 0,001). Največjo diagnostično natančnost testa je v skupini s PE pokazal sEng (AUC = 0,92), v skupini s PE+IUGR je bil to sFlt-1 (AUC = 0,95) in v skupini z IUGR pa PI (AUC = 0,98). Najboljše razlikovanje med kontrolno skupino in skupino s PE je pokazl razmerje (sFlt-1/PlGF)+PI+RI (AUC = 0,93), v skupini z IUGR in PE+IUGR pa je bil to PlGF/(sFlt- 1+sEng)+PI+RI (AUC = 0,98 AUC = 0,99). Največjo diagnostično natančnost testov za diagnozo PE je izkazal, sEng (AUC = 0,92) ter kombinacija (sFlt-1/PlGF)+PI+RI (AUC = 0,93) za diagnozo PE+IUGR, sFlt-1 (AUC = 0,95) in kombinaciji (sFlt-1/PlGF)+PI+RI (AUC = 0,98) in PlGF/(sFlt-1+sEng)+PI+RI (AUC = 0,98) za diagnoszo IUGR pa PI (AUC = 0,98) in kombinacija PlGF/(sFlt-1+sEng)+PI+RI (AUC = 0,99). V zadnjem delu raziskave smo primerjali manjše število primerov s PE in zastojem v rasti ali brez (n = 26) z zdravimi nosečnicami (n = 26) in zaznali podobne statistično značilne razlike pri biokemijskih označevalcih in biofizikalnih parametrih izmerjenimi z Dopplerjevo metodo. Prav tako smo v skupini s PE z zastojem v rasti ali brez zaznali tudi statistično višja AIx (p = 0,002) in RHI (p = 0,0138). V tej skupini je imel največjo diagnostično natančnost sEng (AUC = 0,91) in kombinacija PlGF/(sFlt-1+sEng)+PI+RI (AUC = 0,97). Z našimi rezulati smo uspeli delno potrditi vse 3 hipoteze, ter tako z biokemičnimi označevalci in biofizikalnimi meritvami pojasniti spremembe v delovanju posteljice pri PE. Na ta način smo prispevali k boljšemu razumevanju mehanizma nastanka preeklampsije in/ali zastoja v rasti ploda pri nosečnicah s PE. Preeclampsia is one of the hypertensive disorders of pregnancy, defined by the onset of hypertension and proteinuria after 20 weeks of gestation. It affects 2-8% of all pregnant women and, despite advances in diagnosis and treatment, remains a major cause of maternal and perinatal morbidity and mortality. Research has shown that preeclampsia is most likely the result of abnormal remodelling of the spiral arteries in the placenta caused by genetic, immune and environmental factors in the first trimester of pregnancy. Reduced blood supply and oxygenationreperfusion injury to the placenta lead to morphological changes in the placenta and the release of inflammatory, antiangiogenic, immune, oxidative and vasoconstrictive factors into the maternal circulation, which in turn cause endothelial dysfunction and other characteristics of preeclampsia. The same aetiopathogenesis can also be observed in intrauterine growth restriction, which is a frequent but not necessary accompaniment of preeclampsia. The aim of our study was to use biochemical markers, biophysical parameters and their combinations to elucidate the changes in placental function in preeclampsia and to determine their association with the likelihood of individual and combined complications in pregnancy. We intended to test three hypotheses: 1. In preeclampsia, when the augmentation index (AIx) is elevated and the reactive hyperemia index (RHI) is reduced, placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) levels are reduced, concentrations of soluble fms-like tyrosine kinase (sFlt-1), inhibin A, placental protein 13 (PP13), soluble endoglin (sEng) and tumor necrosis factor alpha (TNF-α) were elevated. 2. An elevated sFlt-1/PlGF ratio in pregnant women with preeclampsia is associated with elevated levels of PP13, sEng and inhibin A, which is probably due to insufficient blood supply and hypoxia in the placental tissue. 3. An elevated sFlt-1/PlGF ratio in pre-eclampsia is associated with an increased augmentation index and an increased degree of endothelial dysfunction. To this end, we compared biochemical markers and biophysical parameters between different groups of subjects with pregnancy complications and a control group of women with normal pregnancies. The study included 36 healthy pregnant women, 30 pregnant women with preeclampsia without intrauterine growth restriction (PE), 43 pregnant women with preeclampsia and intrauterine growth restriction (PE+IUGR) and 16 pregnant women with intrauterine growth restriction only (IUGR). Serum samples were assayed for VEGF, PlGF, sFlt-1, sEng, PP13, inhibin A and TNF-α, and urine samples were used to determine the protein concentrations. Uterine artery blood flow indices were measured by Doppler ultrasound and reactive hyperemia index (RHI) and augmentation index (AIx) by peripheral arterial tonometry. In the first part of the study, where we compared a group of healthy pregnant women with a group with preeclampsia with or without intrauterine growth restriction, we found statistically significantly higher values of sFlt-1 (p < 0.001), sEng (p < 0.001), inhibin A (p = 0.001), sFlt-1/PlGF ratio (p < 0.0001), pulsatility index (PI) (p < 0.001), resistance index (RI) (p < 0.001) and the presence of bilateral notch (p < 0.001). Statistically significant lower values were found for PlGF (p < 0.001) and in the ratio PlGF/(sFlt-1+sEng) (p < 0.0001). Among the individual markers, sFlt-1 (AUC = 0.92) and sEng (AUC = 0.92) and the marker combination (sFlt-1/PlGF)+PI+RI (AUC = 0.97) showed the highest diagnostic accuracy of the test for the diagnosis of PE irrespective of intrauterine growth reastriction. In the second part of the study, when comparing the group of healthy pregnant women with the groups with PE, IUGR and PE+IUGR, we reached similar findings as in the first part of the study. In addition, when comparing between groups of subjects with pregnancy complications, we found statistically significantly higher sFlt-1 and sEng values in the PE+IUGR group compared with the IUGR group (p < 0.001 p < 0.001), as well as higher PI and RI values in the IUGR group compared with the PE group (p < 0.001 p < 0.001), and in the PE+IUGR group compared with the PE group (p < 0.001 p < 0.001). The highest diagnostic accuracy of the test was demonstrated by sEng (AUC = 0.92) in the PE group, sFlt-1 (AUC = 0.95) in the PE+IUGR group and PI (AUC = 0.98) in the IUGR group. The best discrimination between the control group and the PE group was shown by the ratio (sFlt-1/PlGF)+PI+RI (AUC = 0.93), in the IUGR and PE+IUGR groups it was PlGF/(sFlt-1+sEng)+PI+RI (AUC = 0.98 AUC = 0.99). The tests with the highest diagnostic accuracy for PE diagnosis were sEng (AUC = 0.92) and the combination (sFlt-1/PlGF)+PI+RI (AUC = 0.93) for the diagnosis of PE+IUGR, sFlt-1 (AUC = 0.95) and the combinations (sFlt-1/PlGF)+PI+RI (AUC = 0.98) and PlGF/(sFlt-1+sEng)+PI+RI (AUC = 0.98) and for the diagnosis of IUGR, PI (AUC = 0.98) and the combination PlGF/(sFlt-1+sEng)+PI+RI (AUC = 0.99). In the last part of the study, we compared a smaller number of cases with PE pregnancies with or without intrauterine growth restriction (n = 26) with healthy pregnant women (n = 26) and detected similar statistically significant differences in biochemical markers and biophysical parameters measured by Doppler. We also detected statistically higher AIx (p = 0.002) and RHI (p = 0.0138) in the PE group with or without intrauterine growth restriction. In this group, sEng (AUC = 0.91) and the combination PlGF/(sFlt-1+sEng)+PI+RI (AUC = 0.97) had the highest diagnostic accuracy. With our results, we were able to partially confirm all 3 hypotheses, thus using biochemical markers and biophysical measurements to explain the changes in placental function in PE. In this way, we have contributed to a better understanding of the mechanism of preeclampsia and/or intrauterine growth restriction in pregnant women with PE. |
