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ABSTRACT: Fetal growth restriction (FGR) results from placental insufficiency to adequately supply the fetus. This insufficiency involves impaired cytotrophoblast functions, including reduced migration and invasion, proliferation, and syncytium formation. Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a key enzyme in these cellular processes. MT1-MMP exists in various forms: a 63-kDa proenzyme is synthesized as primary translation product, which is cleaved into a 57-kDa membrane-anchored active form. We hypothesized that reduced placental MT1-MMP in FGR impairs trophoblast functions. MT1-MMP mRNA and active enzyme was quantified in placentas from FGR and age-matched control pregnancies. MT1-MMP protein was localized in first-trimester and term placentas. Putative MT1-MMP functions in trophoblasts were determined using two blocking antibodies for measuring migration and proliferation, as well as fusion of primary trophoblasts and trophoblast-derived cells. MT1-MMP was expressed predominantly in the syncytiotrophoblast and the villous and extravillous cytotrophoblasts. In FGR placentas, levels of MT1-MMP mRNA and of active MT1-MMP protein were reduced (-34.2%, P < 0.05, and -21.5%, P < 0.01, respectively), compared with age-matched controls. MT1-MMP-blocking antibodies diminished migration and proliferation and trophoblast fusion. We conclude that reduced placental MT1-MMP in FGR may contribute to the impaired trophoblast functions associated with this pathology.
American Journal Of Pathology 03/2013; · 4.89 Impact Factor
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Ivana Sreckovic,
Ruth Birner-Gruenberger,
Britta Obrist,
Tatjana Stojakovic,
Hubert Scharnagl,
Michael Holzer,
Monika Scholler,
Sonia Philipose,
Gunther Marsche,
Uwe Lang, Gernot Desoye,
Christian Wadsack
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ABSTRACT: In human high-density lipoprotein (HDL) represents the major cholesterol carrying lipoprotein class in cord blood, while cholesterol is mainly carried by low-density lipoprotein in maternal serum. Additionally, to carrying cholesterol, HDL also associates with a range of proteins as cargo. We tested the hypothesis that fetal HDL carries proteins qualitatively and quantitatively different from maternal HDL. These differences then contribute to distinct HDL functionality in both circulations. Shotgun proteomics and biochemical analyses were used to assess composition/function of fetal and maternal HDL isolated from uncomplicated human pregnancies at term of gestation. The pattern of analyzed proteins that were statistically elevated in fetal HDL (apoE, proteins involved in coagulation, transport processes) suggests a particle characteristic for the light HDL(2) sub-fraction. In contrast, proteins that were enriched in maternal HDL (apoL, apoF, PON1, apoD, apoCs) have been described almost exclusively in the dense HDL(3) fraction and relevant to its anti-oxidative function and role in innate immunity. Strikingly, PON1 mass and activity were 5-fold lower (p<0.01) in the fetus, which was accompanied by attenuation of anti-oxidant capacity of fetal HDL. Despite almost equal quantity of CETP in maternal and fetal HDL, its enzymatic activity was 55% lower (p<0.001) in the fetal circulation, whereas LCAT activity was not altered. These findings indicate that maternally-derived HDL differs from fetal HDL with respect to its proteome, size and function. Absence of apoA-1, apoL and PON1 on fetal HDL is associated with decreased anti-oxidative properties together with deficiency in innate immunity collectively indicating dysfunctional HDLs in fetuses.
Biochimica et Biophysica Acta 01/2013; · 4.66 Impact Factor
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ABSTRACT: OBJECTIVE: Chemerin is a novel adipokine implicated in inflammation and obesity. We hypothesized that fetal chemerin would be elevated in gestational diabetes mellitus (GDM) and correlate with fetal and maternal adiposity. DESIGN: Observational, longitudinal study SUBJECTS AND MEASUREMENTS: Fetal chemerin was measured separately in arterial and venous cord blood of 30 infants born to mothers with (n=15) and without GDM (n=15), in their mothers in early 3rd trimester and at delivery and in amniotic fluid (week 32) of women with GDM. Expression of chemerin and its receptor in human fetal tissues commercially available and in placental cells was measured by quantitative PCR. Associations between fetal and maternal anthropometric and metabolic variables were assessed in multivariate regression models. RESULTS: In GDM, fetal arterial, but not venous cord blood chemerin levels were elevated by about 60% (p <0.05). Venous cord blood chemerin was higher in infants of obese women (p<0.01). In multivariate analyses, neither amniotic fluid nor cord blood chemerin levels correlated with birth weight or ponderal index. Both arterial and venous chemerin levels were related to maternal chemerin at birth, and arterial chemerin was associated with GDM status in addition. Maternal levels were unaltered in GDM, but higher in maternal obesity. Fetal liver produces 4-fold more chemerin mRNA than other fetal tissues, whereas its receptor prevails in spleen. CONCLUSIONS: Based on multivariate analyses, fetal growth appears unrelated to fetal chemerin. Maternal obesity and GDM have differential effects on fetal chemerin levels. Site of major production (liver) and action (spleen) differ in human fetal tissues. © 2013 Blackwell Publishing Ltd.
Clinical Endocrinology 01/2013; · 3.17 Impact Factor
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ABSTRACT: Preeclampsia (PE), fetal growth restriction (FGR) and gestational diabetes mellitus (GDM) are major pregnancy complications affecting maternal and fetal health. The placenta and the vasoconstrictor endothelin-1 (ET-1) have a controlling and mediating role in these conditions. This study tested the hypothesis that the expression of ET-1 and its receptors (ET(A) and ET(B)) is altered in these pathologies and differs between early (gestational week [GW]≤34) and late (GW>34) third trimester pregnancies.
The study included 88 women (GW 28-41) with PE (blood pressure >140/90mmHg, protein >300mg/24hrs; n=14), FGR (<10th birthweight centile and pathological umbilical blood flow; n=13), PE+FGR (n=5) and GDM (n=21), and gestational age-matched controls (n=35). ET-1, ET(A) and ET(B) mRNA and ET(A) and ET(B) protein were quantified in placental tissues by real-time PCR and immunoblotting.
The ET/ETR mRNA system is altered in PE and PE+FGR and GDM. Expression of ET-1, ET(A) and ET(B) is upregulated in early onset PE and PE+FGR with stronger effect in PE+FGR. GDM down regulated ET/ETR mRNA in the placentas in late third trimester of pregnancy. ET/ETR protein is virtually unchanged.
Early onset PE (≤GW34) with or without FGR is associated with increased mRNA expression of the ET/ETR system, while in late onset PE and GDM the opposite effect was observed. This study supports the emerging concept that early and late onset PE are different diseases.
Life sciences 05/2012; 91(13-14):710-5. · 2.56 Impact Factor
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ABSTRACT: This review aims to provide a comprehensive summary of the aspects of endothelial and vascular dysfunction in the feto-placental vasculature occurring in pregnancy pathologies. This endothelium is continuous with the fetal circulation. Its function and potential dysfunction in pathologies will have a profound impact on fetal development. Gestational diabetes mellitus represents one of these pathologies, in which its associated metabolic derangements will alter feto-placental endothelial functions. These, in turn, may result in functional changes of the placenta, which may entail impaired fetal development. By contrast, changes in the feto-placental vasculature observed in cases of fetal growth restriction and preeclampsia may be causative (fetal growth restriction) or secondary (preeclampsia) for the pathology.
Wiener Medizinische Wochenschrift 05/2012; 162(9-10):220-4.
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ABSTRACT: Phospholipid (PL) transfer protein (PLTP) plays a crucial role in high-density lipoprotein (HDL) metabolism. In the fetal circulation, HDL particles are the main cholesterol carriers and are involved in maternal-fetal cholesterol transfer across human placental endothelial cells (HPEC).
The aim was to investigate local function(s) of PLTP at the fetoplacental endothelium. Because HPEC display morphological and functional diversity when isolated from arteries or veins, we hypothesized that PLTP activity may differ between arterial and venous HPEC.
We determined PLTP mRNA and activity levels from isolated HPEC and investigated PLTP-mediated remodeling of fetal HDL particles and their capacity in mediating cholesterol efflux from HPEC.
Incubation of fetal HDL with active human plasma PLTP resulted in increased particle size (12.6 vs. 13.2 nm, P < 0.05), with a concomitant increase (3.5-fold) in pre-β-mobile HDL particles. Arterial HPEC showed higher Pltp expression levels and secreted PL transfer activity (1.8-fold, P < 0.001) than venous HPEC. In contrast to adult HDL(3), [(3)H]cholesterol efflux to fetal HDL was 21% higher (P < 0.05) from arterial than from venous HPEC. PLTP-facilitated particle conversion increased the cholesterol efflux capacity of fetal HDL to similar extents (55 and 48%, P < 0.001) from arterial and venous HPEC, respectively.
PLTP mediates PL transfer and participates in reverse cholesterol transport pathways at the fetoplacental barrier. Enhanced cellular cholesterol efflux from HPEC to fetal HDL remodeled by PLTP supports the idea of a local atheroprotective role of PLTP in the placental vasculature.
The Journal of clinical endocrinology and metabolism 04/2012; 97(7):2466-74. · 6.50 Impact Factor
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ABSTRACT: Binding of endothelial cell (EC) integrins to extracellular-matrix (ECM) components is one of the key events to trigger intracellular signaling that will ultimately result in proper vascular development. Even within one tissue, the endothelial phenotype differs between arteries and veins. Here, we tested the hypothesis that anchorage-dependent processes, such as proliferation, viability, survival and actin organization of venous (VEC) and arterial EC (AEC) differently depend on ECM proteins. Moreover, because of different oxygen tension in AEC and VEC, we tested oxygen as a co-modulator of ECM effects. Primary human placental VEC and AEC were grown in collagens I and IV, fibronectin, laminin, gelatin and uncoated plates and exposed to 12 and 21% oxygen. Our main findings revealed that VEC are more sensitive than AEC to changes in the ECM composition. Proliferation and survival of VEC, in contrast to AEC, were profoundly increased by the presence of collagen I and fibronectin when compared with gelatin or uncoated plates. These effects were reversed by inhibition of focal adhesion kinase (Fak) and modulated by oxygen. VEC were more susceptible to the oxygen-dependent ECM effects than AEC. However, no differential ECM effect on actin organization was observed between the two cell types. These data provide first evidence that AEC and VEC from the same vascular loop respond differently to ECM and oxygen in a Fak-dependent manner.
Histochemie 02/2012; · 2.59 Impact Factor
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ABSTRACT: Gestational diabetes mellitus (GDM) causes alterations in fetal high-density lipoproteins (HDL). Because phospholipid transfer protein (PLTP) is important for HDL (re)assembly and is expressed in the human placenta, we hypothesized that circulating fetal and/or placental PLTP expression and activity are altered in GDM.
PLTP levels and activity were determined in maternal and fetal sera from GDM and controls. Placental PLTP was immunolocalized, and its expression was measured in placental tissue. PLTP regulation by glucose/insulin was studied in human endothelial cells isolated from placental vessels (HPEC).
Placental Pltp expression was up-regulated in GDM (1.8-fold, P < 0.05). PLTP protein (5-fold, P < 0.01) and activity (1.4- to 2.5-fold) were higher in fetal than in maternal serum. The placental endothelium was identified as a major PLTP location. Insulin treatment of HPEC significantly increased secreted PLTP levels and activity. In GDM, fetal cholesterol, HDL-triglycerides and phospholipids were elevated compared with controls. Fetal PLTP activity was higher than maternal but unaltered in GDM.
HPEC contribute to the release of active PLTP into the fetal circulation. Pltp expression is increased in GDM with hyperglycemia and/or hyperinsulinemia contributing. High PLTP activity in fetal serum may enhance conversion of HDL into cholesterol-accepting particles, thereby increasing maternal-fetal cholesterol transfer.
The Journal of clinical endocrinology and metabolism 11/2011; 97(2):437-45. · 6.50 Impact Factor
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ABSTRACT: Pregestational diabetes retards early embryonic growth. Placental and fetal growth are closely associated, suggesting that placental growth is also impaired. During the first trimester of gestation, oxygen tension rises steeply, leading to excessive production of reactive oxygen species (ROS), which is exacerbated in diabetes and may affect placental development. We hypothesized that oxygen modifies hyperglycemic effects on ROS formation, resulting in decreased first-trimester trophoblast growth. This was tested using a first trimester trophoblast-derived cell line (ACH-3P). Normoglycemia did not alter ACH-3P proliferation at 2.5%, 8%, and 21% oxygen. Hyperglycemic conditions for up to 3 days reduced cell number by 65% and resulted in cell cycle (G(1)- and S-phase) changes but only at 21% oxygen. Proliferation reduction could be partially restored by an inhibitor of mitogen-activated protein kinase (MAPK) ERK1/2 but not of Akt/PkB. Intracellular ROS elevation under hyperglycemia was oxygen independent, whereas mitochondrial superoxide levels were enhanced under hyperglycemia only at 21% oxygen. Intervention to modulate cytosolic and mitochondrial ROS, using ROS formation inducers and inhibitors, did not alter cell growth under hyperglycemia at 21% oxygen. The combination of hyperglycemia and high oxygen levels (21%) reduces proliferation of human first-trimester trophoblasts in a ROS-independent manner involving MAPK. This may account for reduced placental growth and, therefore, also for embryonic growth during the first-trimester pregestational diabetic pregnancies when the oxygen tension increases.
American Journal Of Pathology 11/2011; 180(1):153-64. · 4.89 Impact Factor
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ABSTRACT: Maternal lipoproteins have been studied extensively in human pregnancies, but little is known about the role of fetal lipoproteins. The vascularized human placenta interfaces between the mother and fetus to transfer nutrients for sustaining pregnancy. Unlike that of adults, fetal high-density lipoprotein (HDL), which is in contact with placental vessels, is characterized by a high proportion of apolipoprotein E (apoE). We hypothesize this unique composition of fetal HDL affects key functions of the growing fetal tissues. The aim was to identify genes regulated by apoE-HDL by incubating human placental endothelial cells (HPEC) with either fetal HDL or apoE-rich reconstituted HDL particles (apoE-rHDL). HPEC were exposed to 15 μg/ml fetal HDL, 15 μg/ml apoE-rHDL, or medium for 16 h, respectively. Microarray analysis determined genes regulated by fetal HDL and apoE. Characterization of HDL particles revealed a different hydrodynamic radius for apoE-rHDL (13.70 nm) compared with fetal HDL (18.11 nm). Stepwise gene clustering after microarray experiments identified 79 differentially expressed genes (P < 0.05) when cells were exposed to HDL compared with controls. Among them 16 genes were downregulated, whereas five genes were upregulated by twofold, respectively. When HPEC were incubated with apoE-rHDL 18-fold more genes (1,417, 12% of transcripts) were regulated (P < 0.05) in contrast to HDL. Thereof, 172 genes were downregulated and 376 genes upregulated (twofold). In the common subset of 38 genes regulated by both HDL particles, genes involved in cholesterol biosynthesis and cell protection prevailed. Strikingly, results suggest that HDL has the capability of regulating metallothioneins, which may have an effect on oxidative stress in HPEC.
Physiological Genomics 09/2011; 43(22):1255-62. · 2.73 Impact Factor
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ABSTRACT: As cell cycle regulation is fundamental to the normal growth and development of the placenta, the aim of the present study was to determine the immunolocalizations of cell cycle related proteins, which have key roles in proliferation, differentiation and apoptosis during the development of the rat placenta. Here immunohistochemistry has been used to localize G1 cyclins (D1, D3, E), which are major determinants of proliferation, CIP/KIP inhibitors (p21, p27, p57), p53 as a master regulator and proliferating cell nuclear antigen in all cell types of the rat term placenta. The proportion of each cell type immunolabeled was counted. Cyclin D1 and cyclin D3 were present mostly in cells of the fetal aspect of the placenta, whereas the G1/S cyclin E was present only in the spongio- and labyrinthine trophoblast populations. Among the CIP/KIP inhibitors, p21 was present only in cells of the fetal aspect whereas p27 and p57 were found in all cell types studied. p53 was only found in a small proportion of cells with no co-localization of p53 and p21. The data suggest that the cells of the fetal side of the rat placenta still have some proliferation potential which is kept in check by expression of the CIP/KIP cell cycle inhibitors, whereas cells of the maternal aspect have lost this potential. Apoptosis is only marginal in the term rat placenta. In conclusion, proliferation and apoptosis in rat placental cells appears controlled mostly by the CIP/KIP inhibitors in late pregnancy.
Histochemie 09/2011; 136(3):267-78. · 2.59 Impact Factor
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ABSTRACT: This study addressed the hypothesis that placental endothelial lipase (EL) expression is affected by pregnancies complicated by obesity and gestational diabetes mellitus (GDM).
EL expression in placental tissues from pregnancies complicated by obesity, GDM, or obesity combined with GDM (obese-GDM) was analyzed by quantitative RT-PCR. Moreover, primary placental cells were isolated and treated with insulin, glucose, leptin, or tumor necrosis factor (TNF)-α, and EL expression was measured. Inhibitors of nuclear factor (NF)-κB or mitogen-activated protein kinase (MAPK) signaling were used to detect potential pathways of EL regulation in primary placental endothelial cells (ECs).
In placentas from obese-GDM pregnancies, EL expression was upregulated by 1.9-fold (P < 0.05) compared with lean pregnancies, whereas obesity or GDM alone had no significant effect. Analyses of metabolic parameters in maternal venous and umbilical venous plasma revealed significantly increased insulin and leptin as well as slightly increased glucose and TNF-α values in the obese and obese-GDM groups. Cell culture experiments identified TNF-α and leptin, but not glucose or insulin, as regulators of EL expression in ECs. Induction of EL expression by these mediators occurred in a para/endocrine manner, since only leptin and TNF-α receptors, but not the cytokines themselves, were expressed in ECs. Inhibitor experiments suggested that TNF-α and leptin-mediated upregulation of EL may occur via two different routes. Whereas TNF-α induced EL upregulation in ECs by activation of the NF-κB pathway, leptin did not stimulate NF-κB or MAPK signaling pathways in these cells.
Metabolic inflammation with high leptin and locally increased TNF-α concentrations at the fetal-placental interface regulates placental EL expression.
Diabetes 08/2011; 60(10):2457-64. · 8.29 Impact Factor
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ABSTRACT: Mesenchymal stromal cells derived from the human amnion (hAMSC) currently play an important role in stem cell research, as they are multipotent cells that can be isolated using noninvasive methods and are immunologically tolerated in vivo. The objective of this study was to evaluate their endothelial differentiation potential with regard to a possible therapeutic use in vascular diseases. hAMSC were isolated from human term placentas and cultured in Dulbecco's modified Eagle's medium (DMEM) (non-induced hAMSC) or endothelial growth medium (EGM-2) (induced hAMSC). Induced hAMSC changed their fibroblast-like toward an endothelial-like morphology, and were able to take up acetylated low-density lipoprotein and form endothelial-like networks in the Matrigel assay. However, they did not express the mature endothelial cell markers von Willebrand factor and vascular endothelial-cadherin. Gene expression analysis revealed that induced hAMSC significantly downregulated pro-angiogenic genes such as tenascin C, Tie-2, vascular endothelial growth factor A (VEGF-A), CD146, and fibroblast growth factor 2 (FGF-2), whereas they significantly upregulated anti-angiogenic genes such as serpinF1, sprouty1, and angioarrestin. Analysis of protein expression confirmed the downregulation of FGF-2 and Tie-2 (27%±8% and 13%±1% of non-induced cells, respectively) and upregulation of the anti-angiogenic protein endostatin (226%±4%). Conditioned media collected from hAMSC enhanced viability of endothelial cells and had a stabilizing effect on endothelial network formation as shown by lactate dehydrogenase and Matrigel assay, respectively. In summary, endothelial induced hAMSC acquired some angiogenic properties but resisted undergoing a complete differentiation into mature endothelial cells by upregulation of anti-angiogenic factors. Nevertheless, they had a survival-enhancing effect on endothelial cells that might be useful in a variety of cell therapy or tissue-engineering approaches.
Stem cells and development 07/2011; 21(8):1309-20. · 4.15 Impact Factor
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ABSTRACT: Normal human pregnancy is considered a state of enhanced oxidative stress. In pregnancy, it plays important roles in embryo development, implantation, placental development and function, fetal development, and labor. However, pathologic pregnancies, including gestational diabetes mellitus (GDM), are associated with a heightened level of oxidative stress, owing to both overproduction of free radicals and/or a defect in the antioxidant defenses. This has important implications on the mother, placental function, and fetal well-being. Animal models of diabetes have confirmed the important role of oxidative stress in the etiology of congenital malformations; the relative immaturity of the antioxidant system facilitates the exposure of embryos and fetuses to the damaging effects of oxidative stress. Of note, there are only a few clinical studies evaluating the potential beneficial effects of antioxidants in GDM. Thus, whether or not increased antioxidant intake can reduce the complications of GDM in both mother and fetus needs to be explored. This review provides an overview and updated data on our current understanding of the complications associated with oxidative changes in GDM.
Antioxidants & Redox Signaling 06/2011; 15(12):3061-100. · 8.20 Impact Factor
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ABSTRACT: The placenta is positioned between the maternal and fetal circulation and hence plays a key role in transporting maternal nutrients to the developing fetus. Fetal growth changes in the 2 most frequent pregnancy pathologies, gestational diabetes mellitus and fetal growth restriction, are predominantly characterized by an exaggerated and restricted fat accretion, respectively. Glucose, by its regulating effect on fetal insulin concentrations, and lipids have been strongly implicated in fetal fat deposition. Transplacental glucose flux is highly efficient and limited only by nutrient availability (flow-limited)--ie, driven by the maternal-fetal glucose concentration gradient and blood flow, with little, if any, effect of placental morphology, glucose consumption, and transporter expression. This explains why, despite changes in these determinants in both pathologies, transplacental glucose flux is unaltered.
American Journal of Clinical Nutrition 05/2011; 94(6 Suppl):1896S-1902S. · 6.67 Impact Factor
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ABSTRACT: Previously we identified palmitoyl-lysophosphatidylcholine (LPC 16:0), as well as linoleoyl-, arachidonoyl- and oleoyl-LPC (LPC 18:2, 20:4 and 18:1) as the most prominent LPC species generated by the action of endothelial lipase (EL) on high-density lipoprotein (HDL). In the present study, the impact of EL and EL-generated LPC on interleukin-8 (IL-8) synthesis was examined in vitro in primary human aortic endothelial cells (HAEC) and in mice.
Adenovirus-mediated overexpression of the catalytically active EL, but not its inactive mutant, increased endothelial synthesis of IL-8 mRNA and protein in a time- and HDL-concentration-dependent manner. While LPC 18:2 was inactive, LPC 16:0, 18:1 and 20:4 promoted IL-8 mRNA- and protein-synthesis, differing in potencies and kinetics. The effects of all tested LPC on IL-8 synthesis were completely abrogated by addition of BSA and chelation of intracellular Ca(2+). Underlying signaling pathways also included NFkB, p38-MAPK, ERK, PKC and PKA. In mice, adenovirus-mediated overexpression of EL caused an elevation in the plasma levels of MIP-2 (murine IL-8 analogue) accompanied by a markedly increased plasma LPC/PC ratio. Intravenously injected LPC also raised MIP-2 plasma concentration, however to a lesser extent than EL overexpression.
Our results indicate that EL and EL-generated LPC, except of LPC 18:2, promote endothelial IL-8 synthesis, with different efficacy and kinetics, related to acyl-chain length and degree of saturation. Accordingly, due to its capacity to modulate the availability of the pro-inflammatory and pro-adhesive chemokine IL-8, EL should be considered an important player in the development of atherosclerosis.
Atherosclerosis 02/2011; 214(2):338-44. · 3.79 Impact Factor
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Ivana Poparic,
Wolfgang Schreibmayer,
Benedikt Schoser, Gernot Desoye,
Astrid Gorischek,
Heidi Miedl,
Sonja Hochmeister,
Josepha Binder,
Stefan Quasthoff,
Klaus Wagner,
Christian Windpassinger,
Ernst Malle
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ABSTRACT: Four-and-a-half LIM domain protein 1 isoform A (FHL1A) is predominantly expressed in skeletal and cardiac muscle. Mutations in the FHL1 gene are causative for several types of hereditary myopathies including X-linked myopathy with postural muscle atrophy (XMPMA). We here studied myoblasts from XMPMA patients. We found that functional FHL1A protein is completely absent in patient myoblasts. In parallel, expression of FHL1C is either unaffected or increased. Furthermore, a decreased proliferation rate of XMPMA myoblasts compared to controls was observed but an increased number of XMPMA myoblasts was found in the G(0)/G(1) phase. Furthermore, low expression of K(v1.5), a voltage-gated potassium channel known to alter myoblast proliferation during the G(1) phase and to control repolarization of action potential, was detected. In order to substantiate a possible relation between K(v1.5) and FHL1C, a pull-down assay was performed. A physical and direct interaction of both proteins was observed in vitro. In addition, confocal microscopy revealed substantial colocalization of FHL1C and K(v1.5) within atrial cells, supporting a possible interaction between both proteins in vivo. Two-electrode voltage clamp experiments demonstrated that coexpression of K(v1.5) with FHL1C in Xenopus laevis oocytes markedly reduced K(+) currents when compared to oocytes expressing K(v1.5) only. We here present the first evidence on a biological relevance of FHL1C.
PLoS ONE 01/2011; 6(10):e26524. · 4.09 Impact Factor
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Monika Riederer,
Pauli J Ojala,
Andelko Hrzenjak,
Wolfgang F Graier,
Roland Malli,
Michaela Tritscher,
Martin Hermansson,
Bernhard Watzer,
Horst Schweer, Gernot Desoye,
Akos Heinemann,
Sasa Frank
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ABSTRACT: Previously we identified palmitoyl-lysophosphatidylcholine (16:0 LPC), linoleoyl-LPC (18:2 LPC), arachidonoyl-LPC (20:4 LPC), and oleoyl-LPC (18:1 LPC) as the most prominent LPC species generated by the action of endothelial lipase (EL) on high-density lipoprotein. In the present study, the impact of those LPC on prostacyclin (PGI(2)) production was examined in vitro in primary human aortic endothelial cells (HAEC) and in vivo in mice. Although 18:2 LPC was inactive, 16:0, 18:1, and 20:4 LPC induced PGI(2) production in HAEC by 1.4-, 3-, and 8.3-fold, respectively. LPC-elicited 6-keto PGF1α formation depended on both cyclooxygenase (COX)-1 and COX-2 and on the activity of cytosolic phospholipase type IVA (cPLA2). The LPC-induced, cPLA2-dependent (14)C-arachidonic acid (AA) release was increased 4.5-fold with 16:0, 2-fold with 18:1, and 2.7-fold with 20:4 LPC, respectively, and related to the ability of LPC to increase cytosolic Ca(2+) concentration. In vivo, LPC increased 6-keto PGF(1α) concentration in mouse plasma with a similar order of potency as found in HAEC. Our results indicate that the tested LPC species are capable of eliciting production of PGI(2), whereby the efficacy and the relative contribution of underlying mechanisms are strongly related to acyl-chain length and degree of saturation.
The Journal of Lipid Research 10/2010; 51(10):2957-66. · 5.56 Impact Factor
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ABSTRACT: The placental endothelium is unique among the entire human vasculature. The blood enriched in oxygen and nutrients is transported in the veins, whereas the arteries contain deoxygenated blood coming from the fetus. The placental vasculature has to develop rapidly to ensure adequate supply of the fetus. Therefore, factors present in the fetal circulation will stimulate placental angiogenesis. In the third trimester of pregnancy the placental endothelium is richly endowed with insulin receptors. In a pregnancy complicated by maternal diabetes, fetal hyperinsulinemia resulting from maternal and, hence, fetal hyperglycaemia induces changes in the placental vasculature such as increased growth and angiogenesis. This review will discuss general effects of insulin on endothelial cells and further focus on insulin effects on the placental endothelium. Isolation and culture of placental endothelial cells has allowed the identification of insulin effects in vitro. These include metabolic effects of insulin i.e. stimulation of glycogen synthesis, and modulation of angiogenesis on the placental arterial endothelium i.e. regulation of ephrin-B2 expression, an arterial specific signalling molecule implicated in sprouting. The effect of insulin on ephrin-B2 in placental arterial endothelial cells as well as their particularly high expression levels of insulin receptors and receptors for vascular endothelial growth factors indicate that placental angiogenesis is likely to emanate from the arterial compartment and is stimulated by insulin.
Current Vascular Pharmacology 11/2009; 7(4):460-6. · 2.90 Impact Factor
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ABSTRACT: The placental endothelium is unique among the entire human vasculature. The blood enriched in oxygen and nutrients is transported in the veins, whereas the arteries contain deoxygenated blood coming from the fetus. The placental vasculature has to develop rapidly to ensure adequate supply of the fetus. Therefore, factors present in the fetal circulation will stimulate placental angiogenesis. In the third trimester of pregnancy the placental endothelium is richly endowed with insulin receptors. In a pregnancy complicated by maternal diabetes, fetal hyperinsulinemia resulting from maternal and, hence, fetal hyperglycaemia induces changes in the placental vasculature such as increased growth and angiogenesis. This review will discuss general effects of insulin on endothelial cells and further focus on insulin effects on the placental endothelium. Isolation and culture of placental endothelial cells has allowed the identification of insulin effects in vitro. These include metabolic effects of insulin i.e. stimulation of glycogen synthesis, and modulation of angiogenesis on the placental arterial endothelium i.e. regulation of ephrin-B2 expression, an arterial specific signalling molecule implicated in sprouting. The effect of insulin on ephrin-B2 in placental arterial endothelial cells as well as their particularly high expression levels of insulin receptors and receptors for vascular endothelial growth factors indicate that placental angiogenesis is likely to emanate from the arterial compartment and is stimulated by insulin.
Current Vascular Pharmacology 09/2009; 7(4):460-466. · 2.90 Impact Factor
