Sascha Drewlo

Vascular dysfunction in women with a history of preeclampsia and intrauterine growth restriction: insights into future vascular risk.

Background— Women with a history of placental disease are at increased risk for the future development of vascular disease. It is unknown whether preexisting endothelial dysfunction underlies both the predisposition to placental disease and the later development of vascular disease. The aim of this study was to assess vascular function in postpartum women and to determine whether differences emerged depending on the presentation of placental disease. Methods and Results— Women with a history of early-onset preeclampsia (n=15), late-onset preeclampsia (n=9), intrauterine growth restriction without preeclampsia (n=9), and prior normal pregnancy (n=16) were studied 6 to 24 months postpartum. Flow-mediated vasodilatation and flow-independent (glyceryl trinitrate–induced) vasodilatation were studied through the use of high-resolution vascular ultrasound examination of the brachial artery. Arterial stiffness was assessed by pulse-wave analysis (augmentation index). Laboratory assessment included circulating angiogenic factors (vascular endothelial growth factor, soluble fms-like tyrosine kinase 1, placental growth factor, and soluble endoglin). Flow-mediated vasodilatation was significantly reduced in women with previous early-onset preeclampsia and intrauterine growth restriction compared with women with previous late-onset preeclampsia and control subjects (3.2±2.7% and 2.1±1.2% versus 7.9±3.8% and 9.1±3.5%, respectively; P<0.0001). Flow-independent vasodilatation was similar among all groups. Similarly, the radial augmentation index was significantly increased among women with previous early-onset preeclampsia and intrauterine growth restriction, but not among late preeclamptic women and control subjects (P=0.0105). Circulating angiogenic factors were similar in all groups. Conclusion— Only women with a history of early-onset preeclampsia or intrauterine growth restriction without preeclampsia exhibit impaired vascular function, which might explain their predisposition to placental disease and their higher risk of future vascular disease.

Glial cell missing-1 transcription factor is required for the differentiation of the human trophoblast

Mammalian placentation is a highly regulated process and is dependent on the proper development of specific trophoblast cell lineages. The two major types of trophoblast, villous and extravillous, show mitotic arrest during differentiation. In mice, the transcription factor, glial cell missing-1 (Gcm1), blocks mitosis and is required for syncytiotrophoblast formation and morphogenesis of the labyrinth, the murine equivalent of the villous placenta. The human homolog GCM1 has an analogous expression pattern, but its function is presently unknown. We studied GCM1 function in the human-derived BeWo choriocarcinoma cell line and in first trimester human placental villous and extravillous explants. The GCM1 expression was either inhibited by siRNA and antisense oligonucleotides methods or upregulated by forskolin treatment. Inhibition of GCM1 resulted in an increased rate of proliferation, but prevented de novo syncytiotrophoblast formation in syncytially denuded floating villous explants. GCM1 inhibition prevented extravillous differentiation along the invasive pathway in extravillous explants on matrigel. By contrast, forskolin-induced expression of GCM1 reduced the rate of proliferation and increased the rate of syncytialization in the floating villous explant model. Our studies show that GCM1 has a distinct role in the maintenance, development and turnover of the human trophoblast. Alterations in GCM1 expression or regulation may explain several aspects of two divergent severe placental insufficiency syndromes, namely preeclampsia and intrauterine growth restriction, which cause extreme preterm birth.

Efficacy of epidural perineural injections with autologous conditioned serum for lumbar radicular compression : An investigator-initiated, prospective, double-blind, reference-controlled study

Study Design. Prospective, double-blind, reference-controlled, investigator-initiated, single center. Objective. To evaluate the efficacy of Autologous Conditioned Serum (ACS; Orthokine) for the treatment of lumbar radicular compression in comparison to triamcinolone. Summary of Background Data. Evidence from animal studies indicates that cytokines such as interleukin-1 play a decisive role in the pathophysiology of lumbar radiculopathy. ACS is enriched in the interleukin-1 receptor antagonist and other anti-inflammatory cytokines. Methods. Thirty-two patients were treated by epidural perineural injections with ACS; 27 patients were treated with 5 mg triamcinolone and 25 patients with 10 mg triamcinolone. Treatment was applied once per week for 3 consecutive weeks and followed for 6 months. The Visual Analogue Scale (VAS) of low back pain was the primary outcome measure. The Oswestry Disability Index (ODI) was the secondary endpoint of the study. All statistical analyses were performed in an exploratory manner using SAS for Windows, version 8.2, on a personal computer. Descriptive statistics were calculated for the VAS and ODI by treatment group and time point. The data were submitted to a repeated-measurements analysis of variance with effects on treatment group, time, and treatment group-by-time interaction. Results. Patients with lumbar back pain who were treated with ACS or the 2 triamcinolone concentrations showed a clinically remarkable and statistically significant reduction in pain and disability, as measured by patient administered outcome measurements. From Week 12 to the final evaluation at Week 22, injections with ACS showed a consistent pattern of superiority over both triamcinolone groups with regard to the VAS score for pain, but statistical significance was observed only at Week 22 in direct comparison to the triamcinolone 5 group. However, there was no statistically significant difference between the 2 triamcinolone dosages during the 6 months of the study. Conclusion. ACS is an encouraging treatment option for patients with unilateral lumbar radicular compression. The decrease in pain was pronounced, clinically remarkable, and potentially superior to steroid injection.

Evidence Implicating Peroxisome Proliferator-Activated Receptor-γ in the Pathogenesis of Preeclampsia

Preeclampsia, a major cause of maternal and perinatal mortality and morbidity, is thought to be attributed, in part, to impaired trophoblast invasion. Peroxisome proliferator-activated receptors are ligand-activated transcription factors expressed in trophoblasts, which regulate the expression of a number of genes involved in cell differentiation and proliferation. We investigated the effect of the administration of a peroxisome proliferator-activated receptor-&ggr; antagonist during uncomplicated pregnancy in rats. Using an intraperitoneal miniosmotic pump, healthy pregnant rats were administered either vehicle or the peroxisome proliferator-activated receptor-&ggr;–specific antagonist, T0070907 (1 mg/kg per day from gestational days 11–15). Rats treated with T0070907 developed key features of preeclampsia, including elevated mean arterial blood pressure, proteinuria, endothelial dysfunction, reduced pup weight, and increased platelet aggregation. T0070907-treated rats had reduced plasma vascular endothelial growth factor and increased plasma soluble fms-like tyrosine kinase 1. Furthermore, increases in total placental soluble fms-like tyrosine kinase 1 mRNA and fms-like tyrosine kinase 1 protein were also demonstrated, suggesting the placenta as the main contributor to the increased circulating levels of soluble fms-like tyrosine kinase 1. The labyrinthine trophoblast in the placentas of T0070907-treated rats were less differentiated, had increased cellular proliferation, and were strongly immunopositive for CD-31 staining, indicating adaptive angiogenesis. The present study suggests that peroxisome proliferator-activated receptor-&ggr; may play a pivotal role in the progression of a healthy pregnancy and may critically regulate the risk of preeclampsia. These findings have important implications regarding the underlying etiology of preeclampsia and potential therapeutic targets.

Peroxisome Proliferator-Activated Receptor-γ as a Potential Therapeutic Target in the Treatment of Preeclampsia

Preeclampsia is a multisystemic disorder of pregnancy characterized by hypertension, proteinuria, and maternal endothelial dysfunction. It is a major cause of maternal and perinatal morbidity and mortality and is thought to be attributable, in part, to inadequate trophoblast invasion. Peroxisome proliferator-activated receptor-&ggr; (PPAR-&ggr;) is a ligand-activated transcription factor expressed in trophoblasts, and the vasculature of which activation has been shown to improve endothelium-dependent vasodilatation in hypertensive conditions. We investigated the effects of the administration of a PPAR-&ggr; agonist using the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. The selective PPAR-&ggr; agonist, rosiglitazone, was administered to pregnant rats that had undergone RUPP surgery. To investigate whether any observed beneficial effects of PPAR-&ggr; activation were mediated by the antioxidant enzyme, heme oxygenase 1, rosiglitazone was administered in combination with the heme oxygenase 1 inhibitor tin-protoporphyrin IX. RUPP rats were characterized by hypertension, endothelial dysfunction, and elevated microalbumin:creatinine ratios. Rosiglitazone administration ameliorated hypertension, improved vascular function, and reduced the elevated microalbumin:creatinine ratio in RUPP rats. With the exception of microalbumin:creatinine ratio, these beneficial effects were abrogated in the presence of the heme oxygenase 1 inhibitor. Administration of a PPAR-&ggr; agonist prevented the development of several of the pathophysiological characteristics associated with the RUPP model of preeclampsia, via a heme oxygenase 1–dependent pathway. The findings from this study provide further insight into the underlying etiology of preeclampsia and a potential therapeutic target for the treatment of preeclampsia.

Serum levels of irisin in gestational diabetes mellitus during pregnancy and after delivery

OBJECTIVE Irisin has recently been introduced as a novel an exercise-inducible myokine which improves glucose metabolism in mice. However, regulation of circulating irisin in gestational diabetes mellitus (GDM) and in the peripartal period has not been assessed so far. METHODS Circulating irisin was quantified in 74 GDM patients and in 74 healthy, pregnant, gestational age-matched controls. In a subset of these patients (44 GDM, 41 controls), postpartum follow-up data were also available. In a second study population of 40 healthy women with singleton pregnancies undergoing elective Cesarean section, irisin was assessed in maternal serum before and within 24h after delivery, as well as in umbilical cord blood and in placental tissue. RESULTS In the first study population, median [interquartile range] irisin levels were significantly higher in GDM patients as compared to controls after delivery (previous GDM: 446.3 [146.9]μg/l; controls: 378.0 [111.4]μg/l) but not during pregnancy (GDM: 482.1 [132.1]μg/l; controls: 466.6 [178.0]μg/l). Interestingly, fasting insulin (FI) was independently and positively associated with serum irisin in multivariate analysis during pregnancy. In agreement with these findings, relative changes (ratio) of FI independently and positively predicted relative changes of irisin (ratio) in the second study population. CONCLUSIONS The myokine irisin is independently associated with FI in pregnancy. The physiological significance of these findings needs to be assessed in future experiments.

Revisiting the housekeeping genes of human placental development and insufficiency syndromes.

Gene expression analysis using semi-quantitative RT-PCR is a common tool in placental research. However the comparison of steady-state gene transcription between different clinical groups is dependent upon comparison of target mRNA data with mRNA obtained from so-called housekeeping (HK) genes whose steady-state transcription does not differ significantly between the groups. In this communication, we evaluated the performance of candidate HK genes across nine clinical groups commonly used in placental research. We used the GeNorm method to evaluate qRT-PCR data to determine the performance of candidate HKs.

Angiogenic response of placental villi to heparin

OBJECTIVE: To estimate the angiogenic effect of heparin on human umbilical vein endothelial cells cultured in conditioned media from normal and severely pre-eclamptic human placental villi. METHODS: Normal first- and second-trimester floating placental villi were explanted in control conditions and increasing concentrations of heparin (unfractionated and low molecular weight heparin) across the clinical prophylactic and therapeutic range (0.025–25 units/mL). At 96 hours, the placenta-conditioned media was tested for angiogenic activity in a human umbilical vein endothelial cell in vitro angiogenesis assay. Total capillary-like tube length and number of branch points were determined from photographs that did not contain information about experimental conditions. The response of placenta-conditioned media from preterm severely preeclamptic pregnant women exposed to low molecular weight heparin also was assessed and compared with both preterm and term control groups. RESULTS: Unfractionated heparin significantly promoted angiogenesis (0.25 units/mL compared with control: relative branch points 185±32% [mean±standard error of the mean], P<.05), whereas low molecular weight heparin had no significant effect. Addition of unfractionated or low molecular weight heparin to first- and second-trimester placenta-conditioned media significantly promoted angiogenesis with the response to low molecular weight heparin more than double that of unfractionated heparin (low molecular weight compared with unfractionated heparin at 2.5 units/mL: relative branch points 930±158% compared with 398±90%, P<.05). Placenta-conditioned media from pregnancies with severe preeclampsia arrested angiogenesis in comparison with both preterm and term pregnancies and was not significantly restored by the addition of low molecular weight heparin. CONCLUSION: Unfractionated and low molecular weight heparin promote in vitro angiogenesis in healthy first- and second-trimester placenta-conditioned media. The nonanticoagulant actions of heparin may be relevant to the prevention of severe preeclampsia.

Heparin promotes soluble VEGF receptor expression in human placental villi to impair endothelial VEGF signaling

Summary.  Background: Severe preeclampsia is characterized by hypertension, renal injury and placental dysfunction. Prothrombotic disorders are discovered in 10–20% of women with preeclampsia, providing the rationale for prescribing low‐molecular‐weight heparin (LMWH) in future pregnancies. Heparin has diverse molecular actions and appears to reduce the recurrence risk of preeclampsia in women without prothrombotic disorders. The placenta‐derived anti‐angiogenic splice‐variant protein soluble vascular endothelial growth factor (VEGF) receptor‐1 (sFLT1) is strongly implicated in the pathogenesis of the underlying endothelial dysfunction. As the placental syncytiotrophoblast is the principal source of sFLT1, we tested the hypothesis that heparin suppresses placental sFLT1 secretion. Methods and Results: First trimester placental villi exposed to LMWH (0.25–25 IU mL−1) in an in vitro explant model significantly increased the expression and release of sFLT1 by the syncytiotrophoblast into culture media, reducing phosphorylation of FLT1 and KDR receptors in cultured human umbilical vein endothelial cells. This response was significantly diminished in placental villi from healthy term pregnancies. Placental villi from severely preeclamptic pregnancies had a higher baseline sFLT1 release, compared with first trimester placental villi and did not respond to LMWH treatment. LMWH promoted villous cytotrophoblast proliferation (BrdU incorporation) and impaired syncytial fusion‐differentiation, causing syncytiotrophoblast apoptosis (by caspase 3&7 activity and TUNEL staining) and necrosis (ADP/ATP ratio). Conclusion: LMWH promotes sFLT1 synthesis and release from first trimester placental villi in a manner similar to that of severely preeclamptic placental villi, which antagonizes VEGF signaling in endothelial cells. These effects in part are mediated by an interaction between heparin and the cytotrophoblasts that regenerates the overlying syncytiotrophoblast responsible for sFLT1 secretion into the maternal blood.

Is heparin a placental anticoagulant in high-risk pregnancies?

Randomized control trials show beneficial effects of heparin in high-risk pregnancies to prevent preeclampsia and intrauterine growth restriction. However, the lack of placental pathology data in these trials challenges the assumption that heparin is a placental anticoagulant. Recent data show that placental infarction is probably associated with abnormalities in development of the placenta, characterized by poor maternal perfusion and an abnormal villous trophoblast compartment in contact with maternal blood, than with maternal thrombophilia. At-risk pregnancies may therefore be predicted by noninvasive prenatal testing of placental function in mid-pregnancy. Heparin has diverse cellular functions that include direct actions on the trophoblast. Dissecting the non-anticoagulant actions of heparin may indicate novel and safer therapeutic targets to prevent the major placental complications of pregnancy.