Meta-analysis of data from human ex vivo placental perfusion studies on genotoxic and immunotoxic agents within the integrated European project NewGeneris

AbstractThe placental passage of humulone and protopine was investigated with a human ex vivo placental perfusion model. The model was first validated with diazepam and citalopram, 2 compounds known to cross the placental barrier, and antipyrine as a positive control. All compounds were quantified by partially validated U(H)PLC-MS/MS bioanalytical methods. Only a small portion of humulone initially present in the maternal circuit reached the fetal circuit. The humulone concentration in the maternal circuit rapidly decreased, likely due to metabolization in the placenta. Protopine was transferred from the maternal to the fetal circuit, with a steady-state reached after 90 min. None of the study compounds affected placental viability or functionality, as glucose consumption, lactate production, beta-human chorionic gonadotropin, and leptin release remained constant. Histopathological evaluation of all placental specimens showed unremarkable, age-appropriate parenchymal maturation with no pathologic findings.

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Ex Vivo Organ Perfusion Studies in Xenograft Research

Xenotransplantation ◽

10.1007/978-3-642-97323-9_25 ◽

1991 ◽

pp. 395-403

Author(s):

K. E. Otte ◽

D. Steinbruchel ◽

E. Kemp

Keyword(s):

Ex Vivo ◽

Organ Perfusion ◽

Perfusion Studies

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Do Neural Stem Cells Have a Choice? Heterogenic Outcome of Cell Fate Acquisition in Different Injury Models

International Journal of Molecular Sciences ◽

10.3390/ijms20020455 ◽

2019 ◽

Vol 20 (2) ◽

pp. 455 ◽

Cited By ~ 3

Author(s):

Felix Beyer ◽

Iria Samper Agrelo ◽

Patrick Küry

Keyword(s):

Stem Cells ◽

Neural Stem Cells ◽

Cell Fate ◽

Ex Vivo ◽

Meta Analysis ◽

Cell Types ◽

Adult Brain ◽

Repair Capacity ◽

Cell Fate Decisions ◽

Limiting Parameters

The adult mammalian central nervous system (CNS) is generally considered as repair restricted organ with limited capacities to regenerate lost cells and to successfully integrate them into damaged nerve tracts. Despite the presence of endogenous immature cell types that can be activated upon injury or in disease cell replacement generally remains insufficient, undirected, or lost cell types are not properly generated. This limitation also accounts for the myelin repair capacity that still constitutes the default regenerative activity at least in inflammatory demyelinating conditions. Ever since the discovery of endogenous neural stem cells (NSCs) residing within specific niches of the adult brain, as well as the description of procedures to either isolate and propagate or artificially induce NSCs from various origins ex vivo, the field has been rejuvenated. Various sources of NSCs have been investigated and applied in current neuropathological paradigms aiming at the replacement of lost cells and the restoration of functionality based on successful integration. Whereas directing and supporting stem cells residing in brain niches constitutes one possible approach many investigations addressed their potential upon transplantation. Given the heterogeneity of these studies related to the nature of grafted cells, the local CNS environment, and applied implantation procedures we here set out to review and compare their applied protocols in order to evaluate rate-limiting parameters. Based on our compilation, we conclude that in healthy CNS tissue region specific cues dominate cell fate decisions. However, although increasing evidence points to the capacity of transplanted NSCs to reflect the regenerative need of an injury environment, a still heterogenic picture emerges when analyzing transplantation outcomes in injury or disease models. These are likely due to methodological differences despite preserved injury environments. Based on this meta-analysis, we suggest future NSC transplantation experiments to be conducted in a more comparable way to previous studies and that subsequent analyses must emphasize regional heterogeneity such as accounting for differences in gray versus white matter.

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Phosphorylation of eNOS initiates excessive NO production in early phases of portal hypertension

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00675.2001 ◽

2002 ◽

Vol 282 (6) ◽

pp. H2084-H2090 ◽

Cited By ~ 57

Author(s):

Yasuko Iwakiri ◽

Ming-Hung Tsai ◽

Timothy J. McCabe ◽

Jean-Philippe Gratton ◽

David Fulton ◽

...

Keyword(s):

Portal Hypertension ◽

Specific Activity ◽

Ex Vivo ◽

Active Form ◽

Initial Increase ◽

No Production ◽

Portal Vein Ligation ◽

Sprague Dawley ◽

Perfusion Studies

Akt, also known as protein kinase B, is a serine/threonine kinase. Akt becomes active when phosphorylated by the activation of receptor tyrosine kinases, G protein-coupled receptors, and mechanical forces such as shear stress. Studies in vitro have shown that Akt can directly phosphorylate endothelial nitric oxide (NO) synthase (eNOS) and activate the enzyme, leading to NO production. The aim of this study was to test the hypothesis that the phosphorylation of eNOS plays a role in the enhanced NO production observed in early portal hypertension. Male Sprague-Dawley rats were subjected to either sham or portal vein ligation (PVL), and mesenteric arterial beds were used for ex vivo perfusion studies. Mesenteric arterial beds from PVL rats had an approximately 60–70% decrease in response to methoxamine (an α1-agonist and vasoconstrictor) compared with the sham group ( P < 0.01). When N G-monomethyl-l-arginine (a NOS inhibitor) was added to the perfusion, the difference in perfusion pressure between the two groups was abolished, suggesting that enhanced NO production in the PVL group blunted the response to the vasoconstrictor. The reduced responsiveness in PVL was not due to changes in eNOS expression but was due to an increase in enzyme-specific activity, suggesting posttranslational modification of eNOS. The phosphorylation of eNOS at Ser1176 was significantly increased by twofold ( P < 0.05) in the PVL group. Furthermore, PVL significantly increased Akt phosphorylation (an active form of Akt) by threefold ( P< 0.05). When vessels were treated with wortmannin (10 nM) to block the phosphatidylinositol-3-OH-kinase/Akt pathway, NO-induced vasodilatation was significantly reduced. These results suggest that the phosphorylation of eNOS by Akt activates the enzyme and may be the first step leading to an initial increase in NO production in portal hypertension.

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Plasma proteins facilitates placental transfer of polystyrene particles

Journal of Nanobiotechnology ◽

10.1186/s12951-020-00676-5 ◽

2020 ◽

Vol 18 (1) ◽

Cited By ~ 1

Author(s):

Michael M. Gruber ◽

Birgit Hirschmugl ◽

Natascha Berger ◽

Magdalena Holter ◽

Snježana Radulović ◽

...

Keyword(s):

Human Plasma ◽

Human Placenta ◽

Plasma Proteins ◽

Placental Transfer ◽

Ex Vivo ◽

Biological Fluids ◽

Protein Corona ◽

Human Albumin ◽

Placental Perfusion ◽

The Impact

Abstract Background Nanoparticles, which are exposed to biological fluids are rapidly interacting with proteins and other biomolecules forming a corona. In addition to dimension, charge and material the distinct protein corona influences the interplay of nanoparticles with tissue barriers. In this study we were focused on the impact of in situ formed human plasma protein corona on the transfer of 80 nm polystyrene nanoparticles (PS-particles) across the human placenta. To study materno-to fetal PS transfer we used the human ex vivo placental perfusion approach, which represents an intact and physiological tissue barrier. To analyze the protein corona of PS particles we performed shotgun proteomics of isolated nanoparticles before and after tissue exposure. Results Human plasma incubated with PS-particles of 80 nm and subsequent formed protein corona enhanced the transfer across the human placenta compared to PS-corona formed by bovine serum albumin and dextran which served as a control. Quantitative and qualitative changes of plasma proteins determined the changes in PS transfer across the barrier. Based on the analysis of the PS-proteome two candidate proteins, namely human albumin and immunoglobulin G were tested if these proteins may account for the enhanced PS-transfer across the placenta. Interestingly, the protein corona formed by human albumin significantly induced the transfer of PS-particles across the tissue compared to the formed IgG-corona. Conclusion In total we demonstrate the PS corona dynamically and significantly evolves upon crossing the human placenta. Thus, the initial composition of PS particles in the maternal circulation is not predictive for their transfer characteristics and performance once beyond the barrier of the placenta. The precise mechanism of these effects remains to be elucidated but highlights the importance of using well designed biological models when testing nanoparticles for biomedical applications.

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The effects of atrial natriuretic factor and angiotensin II on fetal-placental perfusion pressure in the ex vivo cotyledon model

American Journal of Obstetrics and Gynecology ◽

10.1016/0002-9378(95)91341-6 ◽

1995 ◽

Vol 173 (4) ◽

pp. 1143-1147 ◽

Cited By ~ 15

Author(s):

Glenn R. Markenson ◽

Katherine Foley ◽

Arthur S. Maslow ◽

Jerome N. Kopelman

Keyword(s):

Angiotensin Ii ◽

Atrial Natriuretic Factor ◽

Perfusion Pressure ◽

Ex Vivo ◽

Placental Perfusion ◽

Natriuretic Factor ◽

Atrial Natriuretic

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Endothelial von Willebrand factor recruits platelets to atherosclerosis-prone sites in response to hypercholesterolemia

Blood ◽

10.1182/blood.v99.12.4486 ◽

2002 ◽

Vol 99 (12) ◽

pp. 4486-4493 ◽

Cited By ~ 109

Author(s):

Gregor Theilmeier ◽

Carine Michiels ◽

Erik Spaepen ◽

Ingrid Vreys ◽

Désiré Collen ◽

...

Keyword(s):

Von Willebrand Factor ◽

Molecular Mechanisms ◽

Ex Vivo ◽

Human Platelets ◽

Platelet Glycoprotein ◽

Perfusion Studies ◽

Von Willebrand ◽

Willebrand Factor

Platelets are thought to play a causal role during atherogenesis. Platelet-endothelial interactions in vivo and their molecular mechanisms under shear are, however, incompletely characterized. Here, an in vivo platelet homing assay was used in hypercholesterolemic rabbits to track platelet adhesion to plaque predilection sites. The role of platelet versus aortic endothelial cell (EC) activation was studied in an ex vivo flow chamber. Pathways of human platelet immobilization were detailed during in vitro perfusion studies. In rabbits, a 0.125% cholesterol diet induced no lesions within 3 months, but fatty streaks were found after 12 months. ECs at segmental arteries of 3- month rabbits expressed more von Willebrand factor (VWF) and recruited 5-fold more platelets than controls (P < .05, n = 5 and 4, respectively). The 3-month ostia had an increased likelihood to recruit platelets compared to control ostia (56% versus 18%, P < .0001, n = 89 and 63, respectively). Ex vivo, the adhesion of 3-month platelets to 3-month aortas was 8.4-fold increased compared to control studies (P < .01, n = 7 and 5, respectively). In vitro, endothelial VWF–platelet glycoprotein (GP) Ib and platelet P-selectin– endothelial P-selectin glycoprotein ligand 1 interactions accounted in combination for 83% of translocation and 90% of adhesion (P < .01, n = 4) of activated human platelets to activated human ECs. Platelet tethering was mainly mediated by platelet GPIbα, whereas platelet GPIIb/IIIa contributed 20% to arrest (P < .05). In conclusion, hypercholesterolemia primes platelets for recruitment via VWF, GPIbα, and P-selectin to lesion-prone sites, before lesions are detectable.

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