Addition of isosorbide mononitrate to misoprostol for cervical ripening in post-term pregnancy: A randomized controlled trial

ObjectiveThe purpose of this paper is to compare the effect of vaginal isosorbide mononitrate added to misoprostol versus misoprostol alone in cervical ripening and labor induction in post-term pregnancy.MethodsIn this double-blind controlled trial study, 150 pregnant women in post-term pregnancy who were candidates for labor induction were selected. The participants were assigned randomly to receive either vaginal isosorbide mononitrate (IMN) (40mg) or placebo. Misoprostol (25mg) was added to both groups as needed. Time to full cervical ripening, time to delivery, and the amount of misoprostol used in each group were assessed.ResultsThe time interval from the administration of IMN to full cervical ripening was shown to be significantly lower in the IMN+ misoprostol groups versus the comparison group (p=.032). The adjusted analysis of this time interval after controlling for age, BMI, gravidity, and Bishop score on administration remained significantly less (p=.045),the mean difference being −4.85h, CI 95% −9.58 to −.12. Isosorbide treatment resulted in significantly less misoprostol used versus misoprostol alone (2.37±1.02 versus 3.08±1.29), adjusted p-value=.001, CI 95% −1.09 to −.32. We found no significant increase in maternal–fetal outcomes or side effects of the IMN+ misoprostol group compared with the misoprostol group.ConclusionThis study found that intravaginal IMN added to misoprostol is more effective in reducing time to full cervical ripening versus misoprostol alone in post-term pregnancy. It also reduces the need for more misoprostol.

ObjetivoEl objetivo de esta investigación es determinar si el mononitrato de isosorbida vaginal, agregado al misoprostol, acorta el tiempo hasta la maduración cervical completa en el embarazo postérmino.MétodosEn este estudio de prueba controlado doble ciego, se seleccionaron 150 mujeres embarazadas en embarazo postérmino candidatas para la inducción del trabajo de parto. Los participantes fueron asignados al azar para recibir mononitrato de isosorbida vaginal (NMI) (40mg) o placebo. Se añadió misoprostol (25mg) a ambos grupos según fuera necesario. Se evaluaron el tiempo hasta la maduración cervical completa, el tiempo hasta el parto y la cantidad de misoprostol utilizado en cada grupo.ResultadosEl intervalo de tiempo desde la administración de la NMI hasta la maduración cervical completa se mostró significativamente más bajo en los grupos de NMI versus el grupo de comparación (P=0,032). El análisis ajustado de este intervalo de tiempo después de controlar la edad, el IMC, la gravidez y la puntuación de Bishop en la administración se mantuvo significativamente menor (P=0,045) con la diferencia media -4,85h, IC 95% -9,58 a -0,12. El tratamiento con isosorbida dio como resultado una menor cantidad de misoprostol usado significativamente en comparación con el misoprostol solo (2,37±1,02 versus 3,08±1,29), valor de P ajustado=0,001, IC 95% -1,09 a -0,32. No se encontró un aumento significativo en los resultados materno-fetales y los efectos secundarios del grupo de NMI en comparación con el grupo de misoprostol.

Specific suppression of microgliosis cannot circumvent the severe neuropathology in peroxisomal ß-oxidation-deficient mice.

An important hallmark of various neurodegenerative disorders is the proliferation and activation of microglial cells, the resident immune cells of the central nervous system (CNS). Mice that lack multifunctional protein-2 (MFP2), the key enzyme in peroxisomal ß-oxidation, develop excessive microgliosis that positively correlates with behavioral deficits whereas no neuronal loss occurs. However, the precise contribution of neuroinflammation to the fatal neuropathology of MFP2 deficiency remains largely unknown. Here, we first attempted to suppress the inflammatory response by administering various anti-inflammatory drugs but they failed to reduce microgliosis. Subsequently, Mfp2-/- mice were treated with the selective colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 as microglial proliferation and survival is dependent on CSF1R signaling. This resulted in the elimination of >95% of microglia from control mice but only 70% of the expanded microglial population from Mfp2-/- mice. Despite microglial diminution in Mfp2-/- brain, inflammatory markers remained unaltered and residual microglia persisted in a reactive state. CSF1R inhibition did not prevent neuronal dysfunction, cognitive decline and clinical deterioration of Mfp2-/- mice. Collectively, the unaltered inflammatory profile despite suppressed microgliosis concurrent with persevering clinical decline strengthens our hypothesis that neuroinflammation importantly contributes to the Mfp2-/- phenotype.

Plate tectonics on the Earth triggered by plume-induced subduction initiation.

Scientific theories of how subduction and plate tectonics began on Earth--and what the tectonic structure of Earth was before this--remain enigmatic and contentious. Understanding viable scenarios for the onset of subduction and plate tectonics is hampered by the fact that subduction initiation processes must have been markedly different before the onset of global plate tectonics because most present-day subduction initiation mechanisms require acting plate forces and existing zones of lithospheric weakness, which are both consequences of plate tectonics. However, plume-induced subduction initiation could have started the first subduction zone without the help of plate tectonics. Here, we test this mechanism using high-resolution three-dimensional numerical thermomechanical modelling. We demonstrate that three key physical factors combine to trigger self-sustained subduction: (1) a strong, negatively buoyant oceanic lithosphere; (2) focused magmatic weakening and thinning of lithosphere above the plume; and (3) lubrication of the slab interface by hydrated crust. We also show that plume-induced subduction could only have been feasible in the hotter early Earth for old oceanic plates. In contrast, younger plates favoured episodic lithospheric drips rather than self-sustained subduction and global plate tectonics.

Farnesylation of Pex19p is not essential for peroxisome biogenesis in yeast and mammalian cells.

Pex19p exhibits a broad binding specificity for peroxisomal membrane proteins (PMPs), and is essential for the formation of functional peroxisomal membranes. Pex19p orthologues contain a C-terminal CAAX motif common to prenylated proteins. In addition, Saccharomyces cerevisiae and Chinese hamster Pex19p are at least partially farnesylated in vivo. Whether farnesylation of Pex19p plays an essential or merely ancillary role in peroxisome biogenesis is currently not clear. Here, we show that (i) nonfarnesylated and farnesylated human Pex19p display a similar affinity towards a select set of PMPs, (ii) a variant of Pex19p lacking a functional farnesylation motif is able to restore peroxisome biogenesis in Pex19p-deficient cells, and (iii) peroxisome protein import is not affected in yeast and mammalian cells defective in one of the enzymes involved in the farnesylation pathway. Summarized, these observations indicate that the CAAX box-mediated processing steps of Pex19p are dispensable for peroxisome biogenesis in yeast and mammalian cells.

[New treatment strategies for hypertension. Which guidelines and how to apply them]. / Nouvelles stratégies thérapeutiques dans l'hypertension artérielle. Quelles recommandations et comment les appliquer?

The diagnosis of hypertension by blood pressure measurements taken in the physician's office has been called into question by several studies. The onset of cardiovascular events appears to correlate better with ambulatory blood pressure measurements than with those taken during consultation (either "white coat" or masked hypertension). While the US, WHO, French and European guidelines diverge as to the specific antihypertensive drug among the seven classes available should be chosen for first-line treatment, there is a consensus for specific choices as a function of the type of hypertension. In any case, most treatment trials show that more than two antihypertensive drugs are often necessary. Treatment can thus begin with two drugs. The optimal target blood pressure is defined by the US JNC7 according to whether the patient also has diabetes or a nephropathy. When hypertension is uncomplicated, the target level is 140/90 mmHg. In the case of diabetes or nephropathy, it is 130/80 mmHg. In all cases, diet and exercise changes are also necessary and it is essential that patients understand them if they are to comply with them. Diastolic blood pressure remains the most important figure for those younger than 50 years, but afterwards, systolic pressure is more relevant. Aortic pressure may be more closely associated with cardiovascular risk than the blood pressure measured at the brachial artery. The concept of comprehensive management is radically modifying our behavior : the hypertensive patient is now above all a patient at high cardiovascular risk and the treatments to consider must not be limited to antihypertensive drugs but must also include treatment of other cardiovascular risk factors (aspirin, statins, smoking cessation, etc.).

The neuronal migration defect in mice with Zellweger syndrome (Pex5 knockout) is not caused by the inactivity of peroxisomal beta-oxidation.

The purpose of this study was to investigate whether deficient peroxisomal beta-oxidation is causally involved in the neuronal migration defect observed in Pex5 knockout mice. These mice are models for Zellweger syndrome, a peroxisome biogenesis disorder. Neocortical development was evaluated in mice carrying a partial or complete defect of peroxisomal beta-oxidation at the level of the second enzyme of the pathway, namely, the hydratase-dehydrogenase multifunctional/bifunctional enzymes MFP1/L-PBE and MFP2/D-PBE. In contrast to patients with multifunctional protein 2 deficiency who present with neocortical dysgenesis, impairment of neuronal migration was not observed in the single MFP2 or in the double MFP1/MFP2 knockout mice. At birth, the double knockout pups displayed variable growth retardation and about one half of them were severely hypotonic, whereas the single MFP2 knockout animals were all normal in the perinatal period. These results indicate that in the mouse, defective peroxisomal beta-oxidation does not cause neuronal migration defects by itself. This does not exclude that the inactivity of this metabolic pathway contributes to the brain pathology in mice and patients with complete absence of functional peroxisomes.

Mitochondrial alterations caused by defective peroxisomal biogenesis in a mouse model for Zellweger syndrome (PEX5 knockout mouse).

Zellweger syndrome (cerebro-hepato-renal syndrome) is the most severe form of the peroxisomal biogenesis disorders leading to early death of the affected children. To study the pathogenetic mechanisms causing organ dysfunctions in Zellweger syndrome, we have recently developed a knockout-mouse model by disrupting the PEX5 gene, encoding the targeting receptor for most peroxisomal matrix proteins (M Baes, P Gressens, E Baumgart, P Carmeliet, M Casteels, M Fransen, P Evrard, D Fahimi, PE Declercq, D Collen, PP van Veldhoven, GP Mannaerts: A mouse model for Zellweger syndrome. Nat Genet 1997, 17:49-57). In this study, we present evidence that the absence of functional peroxisomes, causing a general defect in peroxisomal metabolism, leads to proliferation of pleomorphic mitochondria with severe alterations of the mitochondrial ultrastructure, changes in the expression and activities of mitochondrial respiratory chain complexes, and an increase in the heterogeneity of the mitochondrial compartment in various organs and specific cell types (eg, liver, proximal tubules of the kidney, adrenal cortex, heart, skeletal and smooth muscle cells, neutrophils). The changes of mitochondrial respiratory chain enzymes are accompanied by a marked increase of mitochondrial manganese-superoxide dismutase, as revealed by in situ hybridization and immunocytochemistry, suggesting increased production of reactive oxygen species in altered mitochondria. This increased oxidative stress induced probably by defective peroxisomal antioxidant mechanisms combined with accumulation of lipid intermediates of peroxisomal beta-oxidation system could contribute significantly to the pathogenesis of multiple organ dysfunctions in Zellweger syndrome.

Isoprenoid biosynthesis is not compromised in a Zellweger syndrome mouse model.

Because several studies indicated that peroxisomes are important for the biosynthesis of isoprenoids, we wanted to investigate whether a reduced availability of isoprenoids could be one of the pathogenic factors contributing to the severe phenotype of the Pex5(-/-) mouse, a model for Zellweger syndrome. Total cholesterol was determined in plasma, brain and liver of newborn mice. In none of these tissues a significant difference was observed between Pex5(-/-) and wild type or heterozygous mice. The hepatic ubiquinone content was found to be even higher in Pex5(-/-) mice as compared to wild type or heterozygous littermates. To investigate whether the Pex5(-/-) fetuses are able to synthesise their own isoprenoids, fibroblasts derived from these mice were incubated with radiolabeled mevalonolactone as a substrate for isoprenoid synthesis. No significant difference was observed between the cholesterol production rates of Pex5(-/-) and normal fibroblasts. Our results show that there is no deficiency of isoprenoids in newborn Pex5(-/-) mice, excluding the possibility that a lack of these compounds is a determinant factor in the development of the disease state before birth.

Oxidative catabolism of alpha-tocopherol in rat liver microsomes.

The goal of this study was to clarify the mechanism responsible for the catabolism of alpha-tocopherol. The vitamin, bound to albumin, was incubated with rat liver microsomes and appeared to be broken down. Optimal production of the metabolite was obtained when 1 mg of microsomal protein was incubated with 36 microM of alpha-tocopherol in the presence of 1.5 mM of NADPH. Chromatographic and mass spectrometric analyses of the metabolite led to the conclusion that it consists of an omega-acid with an opened chroman ring, although we could not perform nuclear magnetic resonance analysis to confirm this. Our data show that alpha-tocopherol is omega-oxidized to a carboxylic acid and that this process can occur in rat liver microsomes in the presence of NADPH and O2. The oxidation to the quinone structure appears to be a subsequent event that may be artifactual and/or catalyzed by a microsomal enzyme(s).

Further insights into peroxisomal lipid breakdown via alpha- and beta-oxidation.

Mammalian peroxisomes degrade fatty carboxylates via two pathways, beta-oxidation and, as shown more recently, alpha-oxidation. The latter process consists of an activation step, followed by a hydroxylation at position 2 and cleavage of the 2-hydroxyacyl-CoA, generating formyl-CoA (precursor of formate/CO(2)) and, in case of phytanic acid as substrate, pristanal (precursor of pristanic acid). The stereochemistry of the overall pathway, cofactor requirements and substrate specificity of the hydroxylase and the cleavage enzyme, which is homologous with bacterial oxalyl-CoA decarboxylases, will be discussed. With regard to beta-oxidation, peroxisomes contain different acyl-CoA oxidases, multifunctional proteins and thiolases. Based on substrate spectra and stereospecificities of these enzymes, a model was proposed whereby straight chain and branched compounds are degraded by separate pathways. The biochemical findings in mice lacking the D-specific multifunctional protein, however, do not fully support this model. These animals, together with the Pex5(-/-) mice, might be useful to pinpoint the pathological factors contributing to the brain abnormalities in Zellweger patients. Apparently, the deficit in docosahexaenoic acid, presumably formed via peroxisomal beta-oxidation, is not the major cause.

Prenatal and postnatal development of peroxisomal lipid-metabolizing pathways in the mouse.

The ontogeny of the following peroxisomal metabolic pathways was evaluated in mouse liver and brain: alpha-oxidation, beta-oxidation and ether phospholipid synthesis. In mouse embryos lacking functional peroxisomes (PEX5(-/-) knock-out), a deficiency of plasmalogens and an accumulation of the very-long-chain fatty acid C(26:0) was observed in comparison with control littermates, indicating that ether phospholipid synthesis and beta-oxidation are already active at mid-gestation in the mouse. Northern analysis revealed that the enzymes required for the beta-oxidation of straight-chain substrates are present in liver and brain during embryonic development but that those responsible for the degradation of branched-chain substrates are present only in liver from late gestation onwards. The expression pattern of transcripts encoding enzymes of the alpha-oxidation pathway suggested that alpha-oxidation is initiated in the liver around birth and is not active in brain throughout development. Remarkably, a strong induction of the mRNA levels of enzymes involved in alpha-oxidation and beta-oxidation was observed around birth in the liver. In contrast, enzyme transcripts that were expressed in brain were present at rather constant levels throughout prenatal and postnatal development. These results suggest that the defective ether phospholipid synthesis and/or peroxisomal beta-oxidation of straight-chain fatty acids might be involved in the pathogenesis of the prenatal organ defects in peroxisome-deficient mice and men.

Do sphingoid bases interact with the peroxisome proliferator activated receptor alpha (PPAR-alpha)?

In a search for possible endogenous ligands of nuclear receptors that are activated by peroxisome proliferators (PPARs), a solid phase binding assay was developed employing recombinant mouse PPAR-alpha, containing a myc-epitope, a histidine repeat and a kinase A domain. After in vitro labelling with 32P-gamma-ATP, the binding of purified 32P-PPAR-alpha to a panel of different natural and synthetic lipids, immobilized on silica layers, was evaluated. Autoradiographs of the silica layers revealed binding to two main classes of lipophilic compounds. A first class comprised (poly)unsaturated fatty acids. Compounds belonging to a second class were characterized by the presence of an overall positive charge such as long chain amines, sphingoid bases (sphingenine), and lysoglycosphingolipids (psychosine). PPAR-alpha did not bind to N-acylated sphingoid bases (ceramides) or to sphingenine phosphorylated at the primary hydroxy group (sphingenine-1-phosphate). The binding of PPAR-alpha to sphingoid bases might be of interest given the role of PPAR-alpha and sphingolipids in various cellular processes.

Neuronal migration disorder in Zellweger mice is secondary to glutamate receptor dysfunction.

Disorders of neuronal migration in cerebral cortex are associated with neurological impairments, including mental retardation and epilepsy. Their causes and pathophysiology remain largely unknown, however. In patients with Zellweger disease, a lethal panperoxisomal disorder, and in mice lacking the Pxr1 import receptor for peroxisomal matrix proteins, the absence of peroxisomes leads to abnormal neuronal migration. Analysis of Pxr1-/- mice revealed that the migration defect was caused by altered N-methyl-D-aspartate (NMDA) glutamate receptor-mediated calcium mobilization. This NMDA receptor dysfunction was linked to a deficit in platelet-activating factor, a phenomenon related to peroxisome impairment. These findings confirm NMDA receptor involvement in neuronal migration and suggest a link between peroxisome metabolism and NMDA receptor efficacy.

Inactivation of the peroxisomal multifunctional protein-2 in mice impedes the degradation of not only 2-methyl-branched fatty acids and bile acid intermediates but also of very long chain fatty acids.

According to current views, peroxisomal beta-oxidation is organized as two parallel pathways: the classical pathway that is responsible for the degradation of straight chain fatty acids and a more recently identified pathway that degrades branched chain fatty acids and bile acid intermediates. Multifunctional protein-2 (MFP-2), also called d-bifunctional protein, catalyzes the second (hydration) and third (dehydrogenation) reactions of the latter pathway. In order to further clarify the physiological role of this enzyme in the degradation of fatty carboxylates, MFP-2 knockout mice were generated. MFP-2 deficiency caused a severe growth retardation during the first weeks of life, resulting in the premature death of one-third of the MFP-2(-/-) mice. Furthermore, MFP-2-deficient mice accumulated VLCFA in brain and liver phospholipids, immature C(27) bile acids in bile, and, after supplementation with phytol, pristanic and phytanic acid in liver triacylglycerols. These changes correlated with a severe impairment of peroxisomal beta-oxidation of very long straight chain fatty acids (C(24)), 2-methyl-branched chain fatty acids, and the bile acid intermediate trihydroxycoprostanic acid in fibroblast cultures or liver homogenates derived from the MFP-2 knockout mice. In contrast, peroxisomal beta-oxidation of long straight chain fatty acids (C(16)) was enhanced in liver tissue from MFP-2(-/-) mice, due to the up-regulation of the enzymes of the classical peroxisomal beta-oxidation pathway. The present data indicate that MFP-2 is not only essential for the degradation of 2-methyl-branched fatty acids and the bile acid intermediates di- and trihydroxycoprostanic acid but also for the breakdown of very long chain fatty acids.

Docosahexaenoic acid deficit is not a major pathogenic factor in peroxisome-deficient mice.

Docosahexaenoic acid (DHA), a major component of membrane phospholipids in brain and retina, is profoundly reduced in patients with peroxisome biogenesis disorders (Zellweger syndrome). Supplementing newborn patients with DHA resulted in improved muscular tone and visual functions. The purpose of this study was to investigate (a) whether DHA levels were also reduced in newborn PEX5 knockout mice, the mouse model of Zellweger syndrome that we recently generated; (b) whether these levels could be normalized by supplying DHA; and (c) whether this results in longer survival. The DHA concentration in brain of newborn PEX5-/- mice was reduced by 40% as compared with levels in normal littermates; in liver, no differences were noticed. The daily administration of 10 mg of DHA-ethyl ester (EE) to pregnant heterozygous mothers during the last 8 days of gestation resulted in a normalization of brain DHA levels in Zellweger pups. However, no clinical improvement was observed in these pups, and the neuronal migration defect was unaltered. These data suggest that the accretion of DHA in the brain at the end of embryonic development is not only supported by the maternal supply but also depends on synthesis in the fetal brain. Furthermore, the DHA deficit does not seem to be a major pathogenic factor in the newborn Zellweger mice.

Mouse models for peroxisome biogenesis disorders.

The gene knockout technology has been applied to generate mice lacking functional peroxisomes. These mice are a model for Zellweger syndrome and other peroxisome biogenesis disorders that are lethal in early life. Extensive biochemical, ultrastructural, and neurodevelopmental analyses indicate that the peroxisome deficient mice closely mimic the pathology in Zellweger patients and will be a very useful tool to elucidate the pathogenesis of this disease.

Inhibition of plasminogen activators or matrix metalloproteinases prevents cardiac rupture but impairs therapeutic angiogenesis and causes cardiac failure.

Cardiac rupture is a fatal complication of acute myocardial infarction lacking treatment. Here, acute myocardial infarction resulted in rupture in wild-type mice and in mice lacking tissue-type plasminogen activator, urokinase receptor, matrix metalloproteinase stromelysin-1 or metalloelastase. Instead, deficiency of urokinase-type plasminogen activator (u-PA-/-) completely protected against rupture, whereas lack of gelatinase-B partially protected against rupture. However, u-PA-/- mice showed impaired scar formation and infarct revascularization, even after treatment with vascular endothelial growth factor, and died of cardiac failure due to depressed contractility, arrhythmias and ischemia. Temporary administration of PA inhibitor-1 or the matrix metalloproteinase-inhibitor TIMP-1 completely protected wild-type mice against rupture but did not abort infarct healing, thus constituting a new approach to prevent cardiac rupture after acute myocardial infarction.

C-terminal tripeptide Ser-Asn-Leu (SNL) of human D-aspartate oxidase is a functional peroxisome-targeting signal.

The functionality of the C-terminus (Ser-Asn-Leu; SNL) of human d-aspartate oxidase, an enzyme proposed to have a role in the inactivation of synaptically released d-aspartate, as a peroxisome-targeting signal (PTS1) was investigated in vivo and in vitro. Bacterially expressed human d-aspartate oxidase was shown to interact with the human PTS1-binding protein, peroxin protein 5 (PEX5p). Binding was gradually abolished by carboxypeptidase treatment of the oxidase and competitively inhibited by a Ser-Lys-Leu (SKL)-containing peptide. After transfection of mouse fibroblasts with a plasmid encoding green fluorescent protein (GFP) extended by PKSNL (the C-terminal pentapeptide of the oxidase), a punctate fluorescent pattern was evident. The modified GFP co-localized with peroxisomal thiolase as shown by indirect immunofluorescence. On transfection in fibroblasts lacking PEX5p receptor, GFP-PKSNL staining was cytosolic. Peroxisomal import of GFP extended by PGSNL (replacement of the positively charged fourth-last amino acid by glycine) seemed to be slower than that of GFP-PKSNL, whereas extension by PKSNG abolished the import of the modified GFP. Taken together, these results indicate that SNL, a tripeptide not fitting the PTS1 consensus currently defined in mammalian systems, acts as a functional PTS1 in mammalian systems, and that the consensus sequence, based on this work and that of other groups, has to be broadened to (S/A/C/K/N)-(K/R/H/Q/N/S)-L.