A comparative-analysis of glycosaminoglycans from human umbilical arteries in normal subjects and in pathological conditions affecting pregnancy

BACKGROUND: Vascular cells express different phenotypes in adult and fetal vessels, and the extracellular matrix they synthesize should reflect these differences. Alterations of vascular proteoglycan/glycosaminoglycan is verified in disorders such as hypertension and diabetes, and when occurring during pregnancy, they bring about structural changes to fetal vessels that often lead to impaired fetus growth. Yet there is little data about the extracellular matrix of an important human fetal vessel, the umbilical artery.EXPERIMENTAL DESIGN: This study involved the biochemical characterization of the extracellular matrix of normal umbilical arteries, umbilical arteries from complicated pregnancies (maternal hypertension and diabetes and intrauterine growth retardation syndrome), and, for purpose of comparison, normal adult arteries (aorta and iliac and pulmonary arteries). Although the collagen types I:III ratio was determined in some cases, emphasis was placed on analysis of glycosaminoglycans.RESULTS: Normal umbilical arteries differ from normal adult arteries in that they contain greater concentrations of hyaluronic acid and lesser concentrations of heparan sulfate and chondroitin 4-and 6-sulfate. The umbilical artery also differs from adult arteries in the disaccharide composition of its chondroitin and heparan sulfates and in the molecular weight of this latter glycosaminoglycan. The glycosaminoglycan distribution in umbilical arteries derived from complicated pregnancies is roughly similar to that of controls. However, total glycosaminoglycan and collagen were significantly reduced, and the collagen I:III ratio was increased in the umbilical arteries from hypertension-complicated pregnancies.CONCLUSIONS: the glycosaminoglycan composition of the normal umbilical artery, a fully differentiated tissue, differs in many aspects from that of normal adult arteries. of the cases of complicated pregnancies studied, the extracellular matrix of umbilical arteries was altered only in maternal hypertension. The changes, notably a mild fibrosis, were not very pronounced and should not impair hemodynamic properties of the vessel.

Alterações do fluxo sanguíneo em artéria umbilical na síndrome hipertensiva gestacional e suas implicações nos resultados neonatais

OBJETIVO: Avaliar as características antropométricas, a morbidade e mortalidade de recém-nascidos (RN) prematuros nascidos vivos de mães hipertensas em função da presença ou não de diástole zero (DZ) ou reversa (DR) na doplervelocimetria arterial umbilical. MÉTODOS: Estudo prospectivo, envolvendo RN prematuros nascidos vivos de gestantes hipertensas, com idade gestacional entre 25 e 33 semanas, submetidas à doplervelocimetria da artéria umbilical nos 5 dias que antecederam o parto, realizado no Hospital do Distrito Federal, entre 1º de novembro de 2009 e 31 de outubro de 2010. Os RN foram estratificados em dois grupos, conforme o resultado da doplervelocimetria da artéria umbilical: Gdz/dr=presença de diástole zero (DZ) ou diástole reversa (DR) e Gn=doplervelocimetria normal. Medidas antropométricas ao nascimento, morbidades e mortalidade neonatal foram comparadas entre os dois grupos. RESULTADOS: Foram incluídos 92 RN, assim distribuídos: Gdz/dr=52 RN e Gn=40 RN. No Gdz/dr a incidência de RN pequenos para idade gestacional foi significativamente maior, com risco relativo de 2,5 (IC95% 1,7‒3,7). No grupo Gdz/dr os RN permaneceram mais tempo em ventilação mecânica mediana 2 (0‒28) e no Gn mediana 0,5 (0‒25), p=0,03. A necessidade de oxigênio aos 28 dias de vida foi maior no Gdz/dr do que no Gn (33 versus10%; p=0,01). A mortalidade neonatal foi maior em Gdz/dr do que em Gn (36 versus 10%; p=0,03; com risco relativo de 1,6; IC95% 1,2 - 2,2). Nessa amostra a regressão logística mostrou que a cada 100 gramas a menos de peso ao nascer no Gdz/dr a chance de óbito aumentou 6,7 vezes (IC95% 2,0 - 11,3; p<0,01). CONCLUSÃO: em RN prematuros de mães hipertensas com alteração na doplervelocimetria da artéria umbilical a restrição do crescimento intrauterino é frequente e o prognóstico neonatal pior, sendo elevado o risco de óbito relacionado ao peso ao nascimento.

[Arterial-adaptive dilatation and Doppler velocimetry in normal fetuses with a single umbilical artery]

PURPOSE: In this study we examined the arterial-adaptive dilatation and Doppler velocimetry, especially RI values, in normal fetuses with a single umbilical artery (SUA). MATERIALS AND METHODS: We studied 195 fetuses from 18 to 39 weeks of gestational age with a prenatally identified SUA retrospectively. They were enrolled in this study if the following information applied: > 18 weeks of gestational age, no structural or chromosomal abnormalities, and histopathological confirmation of SUA. Sonographic examination included evaluation of the umbilical artery resistance and the cross-sectional area of the umbilical cord, and its vessels were measured in all cases. Small for gestational age (SGA) was diagnosed when the birth weight was below the 10th percentile for gestational age. Fetuses with intrauterine growth restriction were defined as those with biometric data below the 5th percentile. RESULTS: There were 119 cases of prenatally identified SUA which met the inclusion criteria. RI values were below the 10th percentile in 33/119 (27.33) and below the 50th percentile in 73/119 (61.33). RI values below the 10th percentile were significantly more likely to be in the normal collective than in the growth restricted collective [31/87 (35.63%) vs. 2/32 (6.25%); p = 0.001]. Even more significant differences became apparent when comparing the RI values below the 50th percentile of both groups. An umbilical artery diameter over the 90th percentile was found in 49 (41.9%) of cases and was significantly more likely to be present in normal growing fetuses than in the growth restricted group. CONCLUSION: Normal fetuses with SUA are at higher risk to be born as SGA. With our study results we can confirm the hypothesis that Doppler flow measurements and arterial diameter in SUA are different from those found in normal fetal umbilical arteries. RI values over the 50th percentile or a cross-sectional area of the artery below 95th percentile after 26th week of gestation significantly increases the risk of SGA.

Mecanismo de centralização: Da insuficiência placentária à adaptação circulatória fetal

The application and development of obstetric Dopplervelocimetry provide a basis for the investigation of placental insuf ciency and demonstrate the dynamic behavior of fetal circulation during hypoxia. In clinical practice, assessing hemodynamics in three vascular regions involved in pregnancy, namely the uterine, umbilical and middle cerebral arteries, has become routine. Roughly, the cerebral artery expresses the balance between uterine artery oxygen supply and umbilical artery oxygen uptake. Currently, when such balance is unfavorable, the fetal cardiac reserve is investigated by assessing the venous duct. However, determining and interpreting vascular resistance indexes is not an easy task. The starting point is to know the physiopathology of placental insuf ciency and fetal circulatory adaptation through which Doppler con rmed its role in the assessment of fetal well-being.

Three-Dimensional Sonographic Assessment of Placental Volume and Vascularization in Pregnancies Complicated by Hypertensive Disorders

Objectives-The purpose of this study was to evaluate the association between placental volumes, placental vascularity, and hypertensive disorders in pregnancy.Methods A prospective case-control study was conducted between April 2011 and July 2012. Placental volumes and vascularity were evaluated by 3-dimensional sonographic, 3-dimensional power Doppler histographic, and 2-dimensional color Doppler studies. Pregnant women were classified as normotensive or hypertensive and stratified by the nature of their hypertensive disorders. The following variables were evaluated: observed-to-expected placental volume ratio, placental volume-to-estimated fetal weight ratio, placental vascular indices, and pulsatility indices of the right and left uterine and umbilical arteries.Results Sixty-six healthy pregnant women and 62 pregnant women with hypertensive disorders were evaluated (matched by maternal age, gestational age at sonography, and parity). Placental volumes were not reduced in pregnancy in women with hypertensive disorders (P > .05). Conversely, reduced placental vascularization indices (vascularization index and vascularization-flow index) were observed in pregnancies complicated by hypertensive disorders (P < .01; P < .01), especially in patients with superimposed preeclampsia (P = .04; P = .02). A weak correlation was observed between placental volumes, placental vascular indices, and Doppler studies of the uterine and umbilical arteries.Conclusions Pregnancies complicated by hypertensive disorders are associated with reduced placental vascularity but not with reduced placental volumes. These findings are independent of changes in uterine artery Doppler studies. Future studies of the prediction of preeclampsia may focus on placental vascularity in combination with results of Doppler studies of the uterine arteries.

PP080. First trimester umbilical artery end-diastolic flow and pulsatility index: Comparison between preeclampsia and control.

INTRODUCTION The appearance of end-diastolic flow velocities (EDF) in the umbilical artery (UA), usually between 10 and 14 weeks of gestation, has been associated with the opening of the spiral arteries and consequently of the intervillous space. OBJECTIVES The aim of our study was to compare first trimester UA pulsatility index (PI) and EDF between women who developed preeclampsia (cases) and controls. METHODS Our database was searched for cases who had UA Doppler between 10-14 weeks. UA PI and EDF were compared between cases and two gestational age (GA) matched controls. RESULTS 15 cases with severe preeclampsia (PE) were matched to 30 controls. GA with negative EDF was lower than with positive EDF (12.1±0.79 vs. 12.8±0.34; p=0.001). UA PI in cases was higher than in controls, although not significant (cases: 2.18±0.6 vs. CONTROLS 1.92±0.48; p=0.12). However, comparing groups with negative EDF, the difference became significant (PI cases: 2.45±0.57 vs. PI controls: 1.94±0.56; p=0.038), while no difference was found comparing groups with positive EDF. CONCLUSION First trimester UA PI is significantly higher in women which will develop PE than in controls. Interestingly, the timing of screening for PE by UA Doppler seems to play an important issue.

A new method for the in vivo identification of mechanical properties in arteries from cine MRI images: Theoretical framework and validation

Quantifying the stiffness properties of soft tissues is essential for the diagnosis of many cardiovascular diseases such as atherosclerosis. In these pathologies it is widely agreed that the arterial wall stiffness is an indicator of vulnerability. The present paper focuses on the carotid artery and proposes a new inversion methodology for deriving the stiffness properties of the wall from cine-MRI (magnetic resonance imaging) data. We address this problem by setting-up a cost function defined as the distance between the modeled pixel signals and the measured ones. Minimizing this cost function yields the unknown stiffness properties of both the arterial wall and the surrounding tissues. The sensitivity of the identified properties to various sources of uncertainty is studied. Validation of the method is performed on a rubber phantom. The elastic modulus identified using the developed methodology lies within a mean error of 9.6%. It is then applied to two young healthy subjects as a proof of practical feasibility, with identified values of 625 kPa and 587 kPa for one of the carotid of each subject.

In vivo mri-based estimation of time-dependent elastic modulus in healthy arteries

The elastic properties of the arterial wall have been the subject of physiological, clinical and biomedical research for many years. There is convincing evidence that the elastic properties of the large arteries are seriously impaired in the presence of cardiovascular disease (CVD), due to alterations in the intrinsic structural and functional characteristics of vessels [1]. Early detection of changes in the elastic modulus of arteries would provide a powerful tool for both monitoring patients at high cardiovascular risk and testing the effects of pharmaceuticals aimed at stabilizing existing plaques by stiffening them or lowering the lipids.

CADASIL: molecular studies on the most common hereditary vascular dementing disorder

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is the most common hereditary vascular dementia. CADASIL is a systemic disease of small and medium-sized arteries although the symptoms are almost exclusively neurological, including migraineous headache, recurrent ischemic episodes, cognitive impairment and, finally, subcortical dementia. CADASIL is caused by over 170 different mutations in the NOTCH3 gene, which encodes a receptor expressed in adults predominantly in the vascular smooth muscle cells. The function of NOTCH3 is not crucial for embryonic development but is needed after birth. NOTCH3 directs postnatal arterial maturation and helps to maintain arterial integrity. It is involved in regulation of vascular tone and in the wound healing of a vascular injury. In addition, NOTCH3 promotes cell survival by inducing expression of anti-apoptotic proteins. NOTCH3 is a membrane-spanning protein with a large extracellular domain (N3ECD) containing 34 epidermal growth factor-like (EGF) repeats and a smaller intracellular domain with six ankyrin repeats. All CADASIL mutations are located in the EGF repeats and the majority of the mutations cause gain or loss of one cysteine residue in one of these repeats leading to an odd number of cysteine residues, which in turn leads to misfolding of N3ECD. This misfolding most likely alters the maturation, targetting, degradation and/or function of the NOTCH3 receptor. CADASIL mutations do not seem to affect the canonical NOTCH3 signalling pathway. The main pathological findings are the accumulation of the NOTCH3 extracellular domain on degenerating vascular smooth muscle cells (VSMCs), accumulation of granular osmiophilic material (GOM) in the close vicinity of VSMCs as well as fibrosis and thickening of arterial walls. Narrowing of the arterial lumen and local thrombosis cause insufficient blood flow, mainly in small arteries of the cerebral white matter, resulting in tissue damage and lacunar infarcts. CADASIL is suspected in patients with a suggestive family history and clinical picture as well as characteristic white matter alterations in magnetic resonance imaging. A definitive verification of the diagnosis can be achieved by identifying a pathogenic mutation in the NOTCH3 gene or through the detection of GOM by electron microscopy. To understand the pathology underlying CADASIL, we have generated a unique set of cultured vascular smooth muscle cell (VSMC) lines from umbilical cord, placental, systemic and cerebral arteries of CADASIL patients and controls. Analyses of these VSMCs suggest that mutated NOTCH3 is misfolded, thus causing endoplasmic reticulum stress, activation of the unfolded protein response and increased production of reactive oxygen species. In addition, mutation in NOTCH3 causes alterations in actin cytoskeletal structures and protein expression, increased branching and abnormal node formation. These changes correlate with NOTCH3 expression levels within different VSMCs lines, suggesting that the phenotypic differences of SMCs may affect the vulnerability of the VSMCs and, therefore, the pathogenic impact of mutated NOTCH3 appears to vary in the arteries of different locations. Furthermore, we identified PDGFR- as an immediate downstream target gene of NOTCH3 signalling. Activation of NOTCH induces up-regulation of the PDGFR- expression in control VSMCs, whereas this up-regulation is impaired in CADASIL VSMCs and might thus serve as an alternative molecular mechanism that contributes to CADASIL pathology. In addition, we have established the congruence between NOTCH3 mutations and electron microscopic detection of GOM with a view to constructing a strategy for CADASIL diagnostics. In cases where the genetic analysis is not available or the mutation is difficult to identify, a skin biopsy is an easy-to-perform and highly reliable diagnostic method. Importantly, it is invaluable in setting guidelines concerning how far one should proceed with the genetic analyses.

In vitro protection of umbilical cord blood–derived primitive hematopoietic stem progenitor cell pool by mannose-specific lectins via antioxidant mechanisms

BACKGROUND: Earlier we reported that an oral administration of two mannose-specific dietary lectins, banana lectin (BL) and garlic lectin (GL), led to an enhancement of hematopoietic stem and progenitor cell (HSPC) pool in mice. STUDY DESIGN AND METHODS: Cord blood–derived CD34+ HSPCs were incubated with BL, GL, Dolichos lectin (DL), or artocarpin lectin (AL) for various time periods in a serum- and growth factor–free medium and were subjected to various functional assays. Reactive oxygen species (ROS) levels were detected by using DCHFDA method. Cell fractionation was carried out using lectin-coupled paramagnetic beads. RESULTS: CD34+ cells incubated with the lectins for 10 days gave rise to a significantly higher number of colonies compared to the controls, indicating that all four lectins possessed the capacity to protect HSPCs in vitro. Comparative analyses showed that the protective ability of BL and GL was better than AL and DL and, therefore, further experiments were carried out with them. The output of long-term culture-initiating cell (LTC-IC) and extended LTC-IC assays indicated that both BL and GL protected primitive stem cells up to 30 days. The cells incubated with BL or GL showed a substantial reduction in the ROS levels, indicating that these lectins protect the HSPCs via antioxidant mechanisms. The mononuclear cell fraction isolated by lectin-coupled beads got enriched for primitive HSPCs, as reflected in the output of phenotypic and functional assays. CONCLUSION: The data show that both BL and GL protect the primitive HSPCs in vitro and may also serve as cost-effective HSPC enrichment tools.

In vitro protection of umbilical cord blood-derived primitive hematopoietic stem progenitor cell pool by mannose-specific lectins via antioxidant mechanisms.

BACKGROUND: Earlier we reported that an oral administration of two mannose-specific dietary lectins, banana lectin (BL) and garlic lectin (GL), led to an enhancement of hematopoietic stem and progenitor cell (HSPC) pool in mice. STUDY DESIGN AND METHODS: Cord blood derived CD34+ HSPCs were incubated with BL, GL, Dolichos lectin (DL), or artocarpin lectin (AL) for various time periods in a serum- and growth factor free medium and were subjected to various functional assays. Reactive oxygen species (ROS) levels were detected by using DCHFDA method. Cell fractionation was carried out using lectin-coupled paramagnetic beads. RESULTS: CD34+ cells incubated with the lectins for 10 days gave rise to a significantly higher number of colonies compared to the controls, indicating that all four lectins possessed the capacity to protect HSPCs in vitro. Comparative analyses showed that the protective ability of BL and GL was better than AL and DL and, therefore, further experiments were carried out with them. The output of long-term culture-initiating cell (LTC-IC) and extended LTC-IC assays indicated that both BL and GL protected primitive stem cells up to 30 days. The cells incubated with BL or GL showed a substantial reduction in the ROS levels, indicating that these lectins protect the HSPCs via antioxidant mechanisms. The mononuclear cell fraction isolated by lectin-coupled beads got enriched for primitive HSPCs, as reflected in the output of phenotypic and functional assays.CONCLUSION: The data show that both BL and GL protect the primitive HSPCs in vitro and may also serve as cost-effective HSPC enrichment tools.