Circulating Growth Differentiation Factor 15 Is Increased Preceding Preeclampsia Diagnosis: Implications as a Disease Biomarker

Background We investigated the biomarker potential of growth differentiation factor 15 (GDF-15), a stress response protein highly expressed in placenta, to predict preeclampsia. Methods and Results In 2 prospective cohorts (cohort 1: 960 controls, 39 women who developed preeclampsia; cohort 2: 950 controls, 41 developed preeclampsia), plasma concentrations of GDF-15 at 36 weeks' gestation were significantly increased among those who developed preeclampsia (P<0.001), area under the receiver operating characteristic curves (AUC) of 0.66 and 0.71, respectively. In cohort 2 a ratio of sFlt-1/PlGF (a clinical biomarker for preeclampsia) had a sensitivity of 61.0% at 83.2% specificity to predict those who will develop preeclampsia (AUC of 0.79). A ratio of GDF-15×sFlt-1/PlGF yielded a sensitivity of 68.3% at 83.2% specificity (AUC of 0.82). GDF-15 was consistently elevated across a number of international cohorts: levels were higher in placenta and blood from women delivering <34 weeks' gestation due to preterm preeclampsia in Melbourne, Australia; and in the blood at 26 to 32 weeks' gestation among 57 women attending the Manchester Antenatal Vascular Service (MAViS, UK) who developed preeclampsia (P=0.0002), compared with 176 controls. In the Preeclampsia Obstetric adVerse Events biobank (PROVE, South Africa), plasma GDF-15 was significantly increased in women with preeclampsia with severe features (P=0.02; n=14) compared to controls (n=14). Conclusions We conclude circulating GDF-15 is elevated among women more likely to develop preeclampsia or diagnosed with the condition. It may have value as a clinical biomarker, including the potential to improve the sensitivity of sFlt-1/PlGF ratio

MMP-15 Is Upregulated in Preeclampsia, but Does Not Cleave Endoglin to Produce Soluble Endoglin

Preeclampsia is a major pregnancy complication, characterized by severe endothelial dysfunction, hypertension and maternal end-organ damage. Soluble endoglin is an anti-angiogenic protein released from placenta and thought to play a central role in causing the endothelial dysfunction and maternal organ injury seen in severe preeclampsia. We recently reported MMP-14 was the protease producing placentally-derived soluble endoglin by cleaving full-length endoglin present on the syncytiotrophoblast surface. This find identifies a specific drug target for severe preeclampsia; interfering with MMP-14 mediated cleavage of endoglin could decrease soluble endoglin production, ameliorating clinical disease. However, experimental MMP-14 inhibition alone only partially repressed soluble endoglin production, implying other proteases might have a role in producing soluble endoglin. Here we investigated whether MMP-15–phylogenetically the closest MMP relative to MMP-14 with 66% sequence similarity–also cleaves endoglin to produce soluble endoglin. MMP-15 was localized to the syncytiotrophoblast layer of the placenta, the same site where endoglin was localized. Interestingly, it was significantly (p = 0.03) up-regulated in placentas from severe early-onset preeclamptic pregnancies (n = 8) compared to gestationally matched preterm controls (n = 8). However, siRNA knockdown of MMP-15 yielded no significant decrease of soluble endoglin production from either HUVECs or syncytialised BeWo cells in vitro. Importantly, concurrent siRNA knockdown of both MMP-14 and MMP-15 in HUVECS did not yield further decrease in soluble endoglin production compared to MMP-14 siRNA alone. We conclude MMP-15 is up-regulated in preeclampsia, but does not cleave endoglin to produce soluble endoglin

Elevated Circulating and Placental SPINT2 Is Associated with Placental Dysfunction

From MDPI via Jisc Publications RouterHistory: accepted 2021-07-08, pub-electronic 2021-07-12Publication status: PublishedBiomarkers for placental dysfunction are currently lacking. We recently identified SPINT1 as a novel biomarker; SPINT2 is a functionally related placental protease inhibitor. This study aimed to characterise SPINT2 expression in placental insufficiency. Circulating SPINT2 was assessed in three prospective cohorts, collected at the following: (1) term delivery (n = 227), (2) 36 weeks (n = 364), and (3) 24–34 weeks’ (n = 294) gestation. SPINT2 was also measured in the plasma and placentas of women with established placental disease at preterm (34 weeks) delivery. Using first-trimester human trophoblast stem cells, SPINT2 expression was assessed in hypoxia/normoxia (1% vs. 8% O2), and following inflammatory cytokine treatment (TNFα, IL-6). Placental SPINT2 mRNA was measured in a rat model of late-gestational foetal growth restriction. At 36 weeks, circulating SPINT2 was elevated in patients who later developed preeclampsia (p = 0.028; median = 2233 pg/mL vs. controls, median = 1644 pg/mL), or delivered a small-for-gestational-age infant (p = 0.002; median = 2109 pg/mL vs. controls, median = 1614 pg/mL). SPINT2 was elevated in the placentas of patients who required delivery for preterm preeclampsia (p = 0.025). Though inflammatory cytokines had no effect, hypoxia increased SPINT2 in cytotrophoblast stem cells, and its expression was elevated in the placental labyrinth of growth-restricted rats. These findings suggest elevated SPINT2 is associated with placental insufficiency

Circulating SPINT1 is a biomarker of pregnancies with poor placental function and fetal growth restriction

Funder: RANZCOG Research Foundation (RANZCOG); doi: https://doi.org/10.13039/501100001104Funder: The Stillbirth FoundationFunder: Tommy's; doi: https://doi.org/10.13039/501100009324Funder: National Institute Health Research Manchester Academic Health Science CentreFunder: RCUK | Biotechnology and Biological Sciences Research Council (BBSRC); doi: https://doi.org/10.13039/501100000268Funder: Centre for Trophoblast ResearchAbstract: Placental insufficiency can cause fetal growth restriction and stillbirth. There are no reliable screening tests for placental insufficiency, especially near-term gestation when the risk of stillbirth rises. Here we show a strong association between low circulating plasma serine peptidase inhibitor Kunitz type-1 (SPINT1) concentrations at 36 weeks’ gestation and low birthweight, an indicator of placental insufficiency. We generate a 4-tier risk model based on SPINT1 concentrations, where the highest risk tier has approximately a 2-5 fold risk of birthing neonates with birthweights under the 3rd, 5th, 10th and 20th centiles, whereas the lowest risk tier has a 0-0.3 fold risk. Low SPINT1 is associated with antenatal ultrasound and neonatal anthropomorphic indicators of placental insufficiency. We validate the association between low circulating SPINT1 and placental insufficiency in two other cohorts. Low circulating SPINT1 is a marker of placental insufficiency and may identify pregnancies with an elevated risk of stillbirth

MMP-15 inhibtion does not decrease soluble endoglin production <i>in vitro</i>.

<p>Treatment of HUVEC cells (<b>A)</b> and syncytialised BeWo cells (<b>B</b>) with MMP-14 siRNA alone or in combination with MMP-15 siRNA induced a significant decline in sEng production compared to scrambled siRNA, whilst MMP-15 siRNA alone had no effect. Data shown as mean±SEM, n = 3 experiments, *p≤0.05.</p

MMP-15 is localised to the syncytiotrophoblast and up-regulated in preeclamptic placenta.

<p>Representative immunohistochemistry for endoglin (<b>A, B</b>) and MMP-15 (<b>D, E</b>), shows both proteins localize to the syncytiotrophoblast in pre-eclamptic (<b>A, D</b>) and pre-term control (<b>B, E</b>) placentas. Immunohistochemistry on serial sections (2 µm) of placenta revealed co-localisation of endoglin (<b>G</b>) and MMP-15 (<b>H</b>) to the syncytiotrophoblast. No staining was observed in isotype controls (<b>C, F</b>). Densitometric analysis of western blots for MMP-15 (<b>I, J</b>) revealed a significant increase in preeclamptic placentas (n = 8) compared to pre-term controls (n = 8). *p≤0.05.</p

Characteristics of study participants.

<p>Data provided as the median, with range given in brackets or percentage as indicated.</p

Analysis of plasma CCL2, 5 and 7 and CX3CL1 (A, B, C and D respectively) in normal control pregnancy (white bars) and miscarriage (black bars) cohorts.

<p>Chemokine levels did not significantly differ between normal control pregnancies and the miscarriage cohort. (N.S. by Kruskal-Wallis test, all analyses P≥0.14). Data expressed as mean ± SEM.</p

Clinical Characteristics of the preeclamptic cohort.

<p>Shown are clinical details of the two cohorts from whom we obtained placentas for our analyses. The preeclamptic cohort all had severe preeclampsia necessitating delivery preterm. Preterm controls where those who were delivered early for other indications but did not have preeclampsia. **p<0.001. SEM =  standard error of the mean, SBP =  systolic blood pressure, DBP =  diastolic blood pressure, BMI =  body mass index and GA =  gestational age.</p

Serum Collected from Preeclamptic Pregnancies Drives Vasoconstriction of Human Omental Arteries—A Novel Ex Vivo Model of Preeclampsia for Therapeutic Development

New-onset maternal hypertension is a hallmark of preeclampsia, driven by widespread endothelial dysfunction and systemic vasoconstriction. Here, we set out to create a new ex vivo model using preeclamptic serum to cause injury to the endothelium, mimicking vascular dysfunction in preeclampsia and offering the potential to evaluate candidate therapeutic interventions. Human omental arteries were collected at caesarean section from normotensive pregnant patients at term (n = 9). Serum was collected from pregnancies complicated by preterm preeclampsia (birth n = 16), term preeclampsia (birth > 37 weeks’ gestation, n = 5), and healthy gestation-matched controls (preterm n = 16, term n = 12). Using wire myography, we performed ex vivo whole vessel assessment where human omental arteries were treated with increasing doses of each serum treatment (2–20%) and vasoreactivity was assessed. All pregnant serum treatments successfully drove vasoconstriction; no significant difference was observed in the degree of vasoconstriction when exposed to preeclamptic or control serum. We further demonstrated the ability of esomeprazole (a candidate therapeutic for preeclampsia; 0.1–100 µM) to drive vasorelaxation of pre-constricted vessels (only with serum from preeclamptic patients). In summary, we describe a novel human physiological model of preeclamptic vascular constriction. We demonstrate its exciting potential to screen drugs for their therapeutic potential as treatment for vasoconstriction induced by preeclampsia