Transport and metabolism of adenosine in diabetic human placenta

1995 ◽  
Vol 7 (6) ◽  
pp. 1499 ◽  
Author(s):  
N Osses ◽  
L Sobrevia ◽  
C Cordova ◽  
SM Jarvis ◽  
DL Yudilevich
Keyword(s):  
Human Placenta ◽  
Brush Border ◽  
Umbilical Vein ◽  
Membrane Vesicles ◽  
Basal Membrane ◽  
Nucleoside Transporter ◽  
Frequent Event ◽  
Significant Difference ◽  
Adenosine Transport ◽  
Umbilical Vein Endothelial Cells

Pregnancy complicated by diabetes is a relatively frequent event and may result in fetal embriopathy. However, little is known regarding whether placental transport functions are altered. In this study, we have compared the activity of the nitrobenzylthioinosine (NBMPR)-sensitive adenosine transporter and adenosine metabolism in human placental brush-border- and basal-membrane vesicles from placentas of normal and diabetic pregnancies. Neither [3H]NBMPR binding, a marker of the facilitative-diffusion nucleoside transporter in the human placenta, nor adenosine metabolism exhibited a significant difference in either the brush-border- or the basal-membrane vesicles between the normal and diabetic group, except for an increased affinity in [3H]NBMPR binding at the basal side in diabetic placenta. This result contrasts with an earlier finding using the same group of patients that adenosine transport is downregulated in umbilical vein endothelial cells from diabetic pregnancies. It is concluded that adenosine transport is modulated selectively in different tissues in diabetic pregnancies.

Adenosine transport in cultured human umbilical vein endothelial cells is reduced in diabetes

1994 ◽  
Vol 267 (1) ◽  
pp. C39-C47 ◽  
Author(s):  
L. Sobrevia ◽  
S. M. Jarvis ◽  
D. L. Yudilevich
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Diffusion Mechanism ◽  
Maximum Velocity ◽  
Facilitated Diffusion ◽  
Nucleoside Transporter ◽  
Apparent Dissociation Constant ◽  
Human Umbilical Vein ◽  
Adenosine Transport ◽  
Umbilical Vein Endothelial Cells

Adenosine transport in cultured human umbilical vein endothelial cells (HUVEC) was characterized and shown to be mediated by a single facilitated diffusion mechanism. Initial rates of adenosine influx at 22 degrees C were saturable [apparent Michaelis constant, 69 +/- 10 microM; maximum velocity (Vmax), 600 +/- 70 pmol.10(6) cells-1.s-1] and inhibited by nitrobenzylthioinosine (NBMPR). Formycin B had an unusually high affinity [inhibitory constant (Ki), 18 +/- 4.3 microM], whereas inosine had a low affinity (Ki, 440 +/- 68 microM) and nucleobases were without effect on adenosine influx. The number of transporters (1.2 x 10(6) sites/cell) was estimated by NBMPR equilibrium binding (apparent dissociation constant, 0.11 +/- 0.01 nM; maximum binding, 2.0 +/- 0.15 pmol/10(6) cells). In addition, we compared these endothelial cells with those obtained from cords from pregnancies complicated by diabetes (HUVEC-D), since embriopathy may occur in these conditions. HUVEC-D exhibited a 2.3-fold reduction in both the Vmax for adenosine influx and the maximum number of NBMPR binding sites (260 +/- 40 pmol.10(6) cells-1.s-1 and 0.86 +/- 0.08 pmol/10(6) cells, respectively). However, the turnover number for each nucleoside transporter in normal and diabetic HUVEC was similar (approximately 300 adenosine molecules/s). Adenosine metabolism at 10 microM in HUVEC-D was modified compared with normal cells. Intracellular phosphorylation (> 90%) was the predominant pathway in normal HUVEC, whereas in HUVEC-D, substantial levels of adenine and adenosine were detected. The present results demonstrate therefore the downregulation of the NBMPR-sensitive nucleoside transporter and changes in adenosine metabolism in HUVEC from diabetic pregnancies.

scholarly journals Acoustic Cell Patterning in Hydrogel for Three-Dimensional Cell Network Formation

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 3
Author(s):  
Kyo-in Koo ◽  
Andreas Lenshof ◽  
Le Thi Huong ◽  
Thomas Laurell
Keyword(s):  
Network Formation ◽  
Umbilical Vein ◽  
Three Dimensional ◽  
Extrusion Process ◽  
Fibroblast Cells ◽  
Glass Capillary ◽  
Cell Network ◽  
Significant Difference ◽  
The One ◽  
Umbilical Vein Endothelial Cells

In the field of engineered organ and drug development, three-dimensional network-structured tissue has been a long-sought goal. This paper presents a direct hydrogel extrusion process exposed to an ultrasound standing wave that aligns fibroblast cells to form a network structure. The frequency-shifted (2 MHz to 4 MHz) ultrasound actuation of a 400-micrometer square-shaped glass capillary that was continuously perfused by fibroblast cells suspended in sodium alginate generated a hydrogel string, with the fibroblasts aligned in single or quadruple streams. In the transition from the one-cell stream to the four-cell streams, the aligned fibroblast cells were continuously interconnected in the form of a branch and a junction. The ultrasound-exposed fibroblast cells displayed over 95% viability up to day 10 in culture medium without any significant difference from the unexposed fibroblast cells. This acoustofluidic method will be further applied to create a vascularized network by replacing fibroblast cells with human umbilical vein endothelial cells.

Dipeptide transport in brush-border membrane vesicles isolated from normal term human placenta

1985 ◽  
Vol 153 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Malliga E. Ganapathy ◽  
Virendra B. Mahesh ◽  
Lawrence D. Devoe ◽  
Frederick H. Leibach ◽  
Vadivel Ganapathy
Keyword(s):  
Human Placenta ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Normal Term ◽  
Dipeptide Transport

scholarly journals Intracellular acidification increases adenosine transport in human umbilical vein endothelial cells

Placenta ◽  
2017 ◽  
Vol 51 ◽  
pp. 10-17 ◽  
Author(s):  
Natalia Celis ◽  
Joaquín Araos ◽  
Carlos Sanhueza ◽  
Fernando Toledo ◽  
Ana R. Beltrán ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Intracellular Acidification ◽  
Human Umbilical Vein ◽  
Adenosine Transport ◽  
Umbilical Vein Endothelial Cells

scholarly journals Endothelial microparticle formation in moderate concentrations of homocysteine and methionine in vitro

2011 ◽  
Vol 16 (1) ◽  
Author(s):  
Małgorzata Sekuła ◽  
Greta Janawa ◽  
Elżbieta Stankiewicz ◽  
Ewa Stępień
Keyword(s):  
Dietary Habits ◽  
Umbilical Vein ◽  
Plasma Concentrations ◽  
Annexin V ◽  
Membrane Vesicles ◽  
Cell Culture Supernatant ◽  
Mthfr Polymorphism ◽  
Blood Disorder ◽  
Umbilical Vein Endothelial Cells

AbstractMicroparticles (MPs) are small membrane vesicles released by stimulated or apoptotic cells, including the endothelium. Hyperhomocysteinemia (HHcy) is a blood disorder characterized by an increase in the plasma concentrations of total homocysteine (Hcy). The plasma Hcy level is determined by environmental factors (dietary habits, i.e. the intake of folic acid, FA) and genetic factors (N 5,N 10-methylenetetrahydro-folate reductase, MTHFR, polymorphism 677C>T). To evaluate whether moderate Hcy concentrations induce endothelial MP formation, the role of FA supplementation and the influence of MTHFR polymorphism were analysed. Human umbilical vein endothelial cells (HUVEC) were treated in vitro with 50 μM of Hcy and methionine (Met). The MP number and apoptotic phenotype were analyzed using flow cytometry. Increasing doses of FA (5, 15 and 50 μM) were used to reduce the HHcy effect. The MTHFR 677C>T polymorphism was determined. HUVEC stimulated by Hcy produced significantly more MPs than HUVEC under the control conditions: 3,551 ± 620 vs 2,270 ± 657 kMP (p = 0.02). Supplementation with FA at concentrations of 5, 15 and 50 μM reduced the MP count in the cell culture supernatant to 345 ± 332, 873 ± 329, and 688 ± 453 kMP, respectively (p = 0.03). MTHFR 677C>T heterozygosity was associated with a significant increase in MP formation after stimulation with Hcy compared to the control conditions: 3,617 ± 152 vs 1,518 ± 343 kMP (p = 0.02). Furthermore, the MTHFR genotype altered MP formation after Met loading. On average, 24% of the entire MP population was apoptotic (annexin V-positive). Endothelial function impairment due to HHcy is related to MP shedding, which may involve platelets and other blood and vascular cells. MP shedding is a physiological response to moderate HHcy.

Sodium-adenosine cotransport in brush-border membranes from rabbit ileum

1990 ◽  
Vol 259 (3) ◽  
pp. G504-G510 ◽  
Author(s):  
S. L. Betcher ◽  
J. N. Forrest ◽  
R. G. Knickelbein ◽  
J. W. Dobbins
Keyword(s):  
Brush Border ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Rabbit Ileum ◽  
Basolateral Membranes ◽  
Brush Border Membranes ◽  
Intestinal Epithelia ◽  
Adenosine Uptake ◽  
Adenosine Concentration ◽  
Adenosine Transport

To determine the mechanism(s) of transcellular adenosine transport in epithelial tissues that possess an adenosine receptor response, we studied [3H]adenosine uptake using vesicles prepared from isolated brush-border and basolateral membranes of the rabbit ileum. In the presence of the adenosine deaminase inhibitor deoxycoformycin uptake of [3H]adenosine into brush-border membrane vesicles is stimulated fivefold by an inwardly directed Na gradient. Na-dependent [3H]adenosine uptake is enhanced and concentrative under conditions that increase inside negativity of vesicles, thus providing evidence for an electrogenic carrier. Na-dependent adenosine uptake is a saturable function of adenosine concentration with a Michaelis-Menten constant of 17.3 +/- 7.1 microM and maximum transport rate of 216.9 +/- 20.2 pmol.min-1.mg protein-1. Both uridine and inosine inhibit [3H]adenosine uptake, suggesting that the Na-dependent transporter has broad substrate specificity for both purine and pyrimidine ribonucleosides. Na-dependent adenosine uptake is inhibited by dipyridamole but is insensitive to 6-(4-nitrobenzyl)thio-9-beta-D-ribofuranosylpurine. We conclude that adenosine is transported across ileal brush-border membranes by a Na-ribonucleoside cotransport system. In contrast, adenosine uptake in basolateral membranes is not stimulated by a Na gradient. These studies show asymmetry in the distribution of transport systems for adenosine in polarized intestinal epithelia.

A New Isoxazolic Compound Acts as α7 Nicotinic Receptor Agonist in Human Umbilical Vein Endothelial Cells

2014 ◽  
Vol 69 (7-8) ◽  
pp. 291-299 ◽  
Author(s):  
Magdalena P. Cortés ◽  
Rocío Alvarez ◽  
Evelyn Sepúlveda ◽  
Felipe Jiménez-Aspee ◽  
Luis Astudillo ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Umbilical Vein ◽  
Therapeutic Angiogenesis ◽  
Dependent Manner ◽  
Human Umbilical Vein ◽  
Α7 Nachr ◽  
Significant Difference ◽  
Umbilical Vein Endothelial Cells

Recent evidence suggests that the α7 nicotinic acetylcholine receptors (α7 nAChRs) participate in the development of angiogenesis and could be a new endothelial target for revascularization in therapeutic angiogenesis. It has been shown that in human umbilical vein endothelial cells (HUVECs) α7 nAChR agonists increase the intracellular calcium concentration ([Ca2+]i), thus inducing proliferation and vessel formation which are important stages of angiogenesis. In the present study we evaluated the effect of new isoxazole compounds on the cytosolic Ca2+ signal in HUVECs using the fluorescent Ca2+ indicator Fluo-3AM and probing the involvement of α7 nAChR by means of pharmacological tools. HUVECs expressed mainly α7 nAChR, since there was no significant difference in the increase in [Ca2+]i induced by nicotine, a non-selective nicotinic agonist, in relation to choline, a selective α7 nAChR agonist. The increase in [Ca2+]i induced by 1 mM choline was inhibited significantly (p = 0.014) in cells which had been pre-incubated for 15 min with methyllycaconitine (MLA), a selective α7 nAChR antagonist. The studied compounds 1, 2, and 3 induced an increase in [Ca2+]i in a dose-dependent manner. Compound 1 at 10 mM induced a greater increase in [Ca2+]i than compounds 2 and 3. The increase in [Ca2+]i induced by compound 1 was significantly inhibited by MLA (p = 0.013) and completely inhibited by mecamylamine, a non-selective nAChR antagonist, indicating that the isoxazolic compound 1 acts as an α7 nAChR agonist.

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