Olivier W.H. van der Heijden

Uterine Artery Remodeling and Reproductive Performance Are Impaired in Endothelial Nitric Oxide Synthase-Deficient Mice

Abstract The progressive rise in uterine blood flow during pregnancy is accompanied by outward hypertrophic remodeling of the uterine artery (UA). This process involves changes of the arterial smooth muscle cells and extracellular matrix. Acute increases in blood flow stimulate endothelial production of nitric oxide (NO). It remains to be established whether endothelial NO synthase (eNOS) is involved in pregnancy-related arterial remodeling. We tested the hypothesis that absence of eNOS results in a reduced remodeling capacity of the UA during pregnancy leading to a decline in neonatal outcome. UA of nonpregnant and pregnant wild-type (Nos3+/+) and eNOS-deficient (Nos3−/−) mice were collected and processed for standard morphometrical analyses. In addition, cross sections of UA were processed for cytological (smoothelin, smooth muscle α-actin) and proliferation (Ki-67) immunostaining. We compared the pregnancy-related changes longitudinally and, together with the data on pregnancy outcome, transversally by analysis of variance with Bonferroni correction. During pregnancy, the increases in radius and medial cross sectional area of Nos3−/− UA was significantly less than those of Nos3+/+ UA. Smooth muscle cell dedifferentiation and proliferation were impaired in gravid Nos3−/− mice as deduced from the lack of change in the expression of smoothelin and smooth muscle α-actin, and the reduced Ki-67 expression. Until 17 days of gestation, litter size did not differ between both genotypes, but at birth the number of viable newborn pups and their weights were smaller in Nos3−/− than in Nos3+/+ mice. We conclude that absence of eNOS adversely affects UA remodeling in pregnancy, which may explain the impaired pregnancy outcome observed in these mice.

Low plasma volume following pregnancy complicated by pre‐eclampsia predisposes for hypertensive disease in a next pregnancy

Objective A large number of women with a history of pre‐eclampsia/HELLP have a low plasma volume at least six months postpartum. The objective of this study was to determine whether a low plasma volume in formerly pre‐eclamptic women and HELLP patients is associated with an increased risk for recurrent hypertensive complications in a next pregnancy.

Uterine Artery Remodeling in Pseudopregnancy Is Comparable to That in Early Pregnancy

Abstract During pregnancy, the lumenal diameter and wall mass of the uterine artery (UA) increase, most likely in response to the increased hemodynamic strain resulting from the chronically elevated uterine blood flow (UBF). In this remodeling process, the phenotype of vascular smooth-muscle cells (VSMC) is transiently altered to enable VSMC proliferation. These phenomena are already seen during early pregnancy, when the rise in UBF is still modest. This raises the question whether the newly instituted endocrine environment of pregnancy is involved in the onset of the pregnancy-related UA remodeling. We tested the hypothesis that the conceptus is not essential for the onset of UA remodeling of pregnancy. Six control and 18 pseudopregnant (Postcopulation Days 5, 11, and 17; n = 6 per subgroup) C57Bl/6 mice were killed and UAs were dissected and processed for either morphometric analysis or immunohistochemistry. The latter consisted of staining UA cross sections for the differentiation markers smooth muscle alpha-actin and smoothelin, and for the proliferation marker MKI67. We analyzed the UA changes in response to pseudopregnancy by ANOVA. Data are presented as mean ± SD. By Day 11 of pseudopregnancy, the UA lumen was 25% wider and the media cross-sectional area 71% larger than in control mice. These differences were accompanied by reduced smoothelin expression and increased proliferation of UA medial VSMC. All UA morphological differences had returned or were in the process of returning to baseline values by Day 17 of pseudopregnancy. The structural and cellular aspects of UA remodeling as seen at midpregnancy are also seen in pseudopregnancy. These results support the concept that the conceptus does not contribute to the initiation of UA remodeling. We suggest that ovarian hormones trigger the onset of UA remodeling.

Aging Blunts Remodeling of the Uterine Artery During Murine Pregnancy

Objective: The progressive increase in uterine blood flow (UBF) during pregnancy is accommodated by morphologic changes in the uterine artery (UA) in a process defined as arterial remodeling. This process is accompanied by changes in cytoskeletal architecture of the arterial smooth muscle cells (SMCs) and surrounding extracellular matrix (ECM). Aging reduces flow-induced arterial remodeling. We studied changes in the murine UA during pregnancy and on the effects of aging on the capacity of the UA to remodel in response to pregnancy. Methods: We determined morphologic and cytologic changes in UA from nonpregnant and pregnant mice aged 12 weeks (young) and 40 weeks (old) and correlated them with their reproductive performance. Results: In young mice, pregnancy induced an early increase in UA wall mass, which preceded lumen widening. These changes were not accompanied by altered densities of elastin and collagen in the ECM of the medial layer. Smooth muscle cell proliferation increased in midepregnancy and was paralleled by a transient decrease in smoothelin and smooth muscle α-actin expression. In old mice, these pregnancy-dependent changes in the UA wall were either absent or markedly reduced. Although by day 11 of pregnancy litter size did not differ between both age groups, the number of viable pups in old mice by day 17 of pregnancy and at birth was 25% and 60% less than in young mice. Conclusions: Outward hypertrophic remodeling of the UA during pregnancy in young mice is characterized by transient phenotypic modulation and proliferation of SMCs and alterations in the composition of the ECM. In contrast, in older mice, UA remodeling is markedly reduced and accompanied with a loss of viable fetuses near term pregnancy.

ALIFE2 study: low-molecular-weight heparin for women with recurrent miscarriage and inherited thrombophilia - study protocol for a randomized controlled trial

BackgroundA large number of studies have shown an association between inherited thrombophilia and recurrent miscarriage. It has been hypothesized that anticoagulant therapy might reduce the number of miscarriages and stillbirth in these women. In the absence of randomized controlled trials evaluating the efficacy of anticoagulant therapy in women with inherited thrombophilia and recurrent miscarriage, a randomized trial with adequate power that addresses this question is needed. The objective of the ALIFE2 study is therefore to evaluate the efficacy of low-molecular-weight heparin (LMWH) in women with inherited thrombophilia and recurrent miscarriage, with live birth as the primary outcome.Methods/DesignRandomized study of LMWH plus standard pregnancy surveillance versus standard pregnancy surveillance alone.Study population: pregnant women of less than 7 weeks’ gestation, and confirmed inherited thrombophilia with a history of 2 or more miscarriages or intra-uterine fetal deaths, or both.Setting: multi-center study in centers from the Dutch Consortium of Fertility studies; centers outside the Netherlands are currently preparing to participate.Intervention: LMWH enoxaparin 40 mg subcutaneously once daily started prior to 7 weeks gestational age plus standard pregnancy surveillance or standard pregnancy surveillance alone.Main study parameters/endpoints: the primary efficacy outcome is live birth. Secondary efficacy outcomes include adverse pregnancy outcomes, such as miscarriage, pre-eclampsia, syndrome of hemolysis, elevated liver enzymes and low platelets (HELLP syndrome), fetal growth restriction, placental abruption, premature delivery and congenital malformations.Safety outcomes include bleeding episodes, thrombocytopenia and skin reactions.DiscussionAfter an initial period of slow recruitment, the recruitment rate for the study has increased. Improved awareness of the study and acknowledgement of the need for evidence are thought to be contributing to the improved recruitment rates. We aim to increase the number of recruiting centers in order to increase enrollment into the ALIFE2 study.The study website can be accessed via www.ALIFE2study.org.Trial registrationThe ALIFE2 study was registered on 19 March 2012 under registration number NTR3361

Neutrophil Extracellular Traps Drive Endothelial-to-Mesenchymal TransitionHighlights

Objective— An excessive release and impaired degradation of neutrophil extracellular traps (NETs) leads to the continuous exposure of NETs to the endothelium in a variety of hematologic and autoimmune disorders, including lupus nephritis. This study aims to unravel the mechanisms through which NETs jeopardize vascular integrity. Approach and Results— Microvascular and macrovascular endothelial cells were exposed to NETs, and subsequent effects on endothelial integrity and function were determined in vitro and in vivo. We found that endothelial cells have a limited capacity to internalize NETs via the receptor for advanced glycation endproducts. An overflow of the phagocytic capacity of endothelial cells for NETs resulted in the persistent extracellular presence of NETs, which rapidly altered endothelial cell–cell contacts and induced vascular leakage and transendothelial albumin passage through elastase-mediated proteolysis of the intercellular junction protein VE-cadherin. Furthermore, NET-associated elastase promoted the nuclear translocation of junctional &bgr;-catenin and induced endothelial-to-mesenchymal transition in cultured endothelial cells. In vivo, NETs could be identified in kidney samples of diseased MRL/lpr mice and patients with lupus nephritis, in whom the glomerular presence of NETs correlated with the severity of proteinuria and with glomerular endothelial-to-mesenchymal transition. Conclusions— These results indicate that an excess of NETs exceeds the phagocytic capacity of endothelial cells for NETs and promotes vascular leakage and endothelial-to-mesenchymal transition through the degradation of VE-cadherin and the subsequent activation of &bgr;-catenin signaling. Our data designate NET-associated elastase as a potential therapeutic target in the prevention of endothelial alterations in diseases characterized by aberrant NET release.

Postpartum Reversal of the Pregnancy-Induced Uterine Artery Remodeling in Young, Aging, and eNOS-Deficient Mice

Objectives. The progressive rise in uterine blood flow (UBF) during pregnancy is accompanied by outward hypertrophic remodeling of the uterine artery (UA). After birth, UBF falls in concert with the sudden decline in uterine metabolic demands. Arterial remodeling associated with the reversal of increased blood flow has been described in large arteries. It is unclear whether this situation applies to small-sized resistance arteries such as the UA. We investigated the pattern of UA remodeling postpartum in relation to age and endothelial nitric oxide synthase (eNOS) deficiency. Methods. Uterine artery of 2 and 10 days postpartum young (age 12 weeks), aged (age 40 weeks), and eNOS-deficient (eNOS —/—, age 12 weeks) mice were dissected and processed for either morphometric analysis (lumen, wall mass) or immunohistochemistry (cellular differentiation, proliferation, and apoptosis). We used data of previously studied control (nonpregnant) and late-pregnant (17 days gestation) mice as reference. Results. By 2 days postpartum, morphometric and cellular characteristics of the UA did not differ from those of late-pregnant UA. By 10 days postpartum, the UA was wider with wall mass being decreased by ~30%. Cytological parameters indicated a stable smooth muscle media. Apoptosis was only present in UA of 2 and 10 days pregnant mice. In eNOS— /— and aged mice, changes were smaller or absent, respectively. Conclusions. The outward hypertrophic response of the UA induced by pregnancy regresses gradually postpartum. We speculate that persisting UA widening facilitates UA remodeling in a next pregnancy thereby favoring placentation and with it, allowing for a higher birth weight as usually observed in a second mammalian pregnancy.

Continuous glucose monitoring during diabetic pregnancy (GlucoMOMS): A multicentre randomized controlled trial

Diabetes is associated with a high risk of adverse pregnancy outcomes. Optimal glycaemic control is fundamental and is traditionally monitored with self‐measured glucose profiles and periodic HbA1c measurements. We investigated the effectiveness of additional use of retrospective continuous glucose monitoring (CGM) in diabetic pregnancies.