Free vitamin B12 and transcobalamin II-vitamin B12 complex uptake by the visceral yolk sac of the sprague-dawley rat: Effect of inhibitors

Polliotti, Bruno; Panigel, M; Miller, Richard K.

doi:10.1016/s0890-6238(97)89180-0

Cited by 7 publications

(3 citation statements)

References 39 publications

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“…The finding of high levels of TC mRNA in the yolk sac placenta suggests that TC synthesis at this site may be important for delivery of Cbl to the fetus. In support of this suggestion are earlier studies (Polliotti et al 1997) that have shown the presence of an endocytic mechanism for the uptake of TC–Cbl in the near‐term rat visceral yolk sac. In contrast to rats, studies in humans using the perfusion technique have shown that Cbl transport across the human placenta as well as in the fetal circulation may be promoted by haptocorrins (Perez‐D'Gregorio & Miller, 1998).…”

Section: Discussionsupporting

confidence: 66%

Rat transcobalamin: cloning and regulation of mRNA expression

Kalra

Seetharam²,

Yammani³

et al. 2004

The Journal of Physiology

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Transcobalamin (TC) has been cloned and used for studying its gene expression in the rat. TC mRNA is distributed widely in adult rat tissues, but at different levels (kidney > liver > lung > yolk sac > intestine > heart > brain > spleen > muscle). TC mRNA levels were 4-fold higher in the jejunum and ileum compared to its levels in the duodenum. During postnatal development, TC mRNA levels in the ileum declined 4-fold from day 4 to day 12, but increased by 5-fold between days 12 and 24. In contrast, TC mRNA levels increased by 2.5-fold in the kidney from day 4 to day 12 and then declined by 2-fold by day 24. Adrenalectomy of adult rats resulted in a 4-fold decline in ileal levels of TC mRNA and a 50% decline in the ileal mucosal formation of the TC-[ 57 Co] cobalamin (Cbl) complex following oral administration of [ 57 Co]Cbl complexed to gastric intrinsic factor (IF). Cortisone treatment reversed these changes noted in the ileum. In contrast to ileum, kidney TC mRNA levels were not altered significantly in adrenalectomized rats before and after cortisone treatment. Taken together, this study has provided evidence for the regulation of TC gene expression in the rat kidney and intestine during their postnatal development, and cortisone selectively regulates ileal but not kidney TC mRNA levels.

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Section: Discussionsupporting

confidence: 66%

Rat transcobalamin: cloning and regulation of mRNA expression

Kalra

Seetharam²,

Yammani³

et al. 2004

The Journal of Physiology

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“…A major challenge in drug therapy is to develop safe and selective targeting strategies during pregnancy [16]. Use of any drug during pregnancy is complicated by concerns of adverse effects on the pregnant woman and the fetus [34].…”

Section: Introductionmentioning

confidence: 99%

Transfer of PAMAM dendrimers across human placenta: Prospects of its use as drug carrier during pregnancy

Menjoge

Rinderknecht

Navath

et al. 2011

Journal of Controlled Release

108

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Dendrimers offer significant potential as nanocarriers for targeted delivery of drugs and imaging agents. The objectives of this study were to evaluate the transplacental transport, kinetics and biodistribution of PAMAM dendrimers ex-vivo across the human placenta in comparison with antipyrine, a freely diffusible molecule, using dually perfused re-circulating term human placental lobules. The purpose of this study is to determine if dendrimers as drug carriers can be used to design drug delivery systems directed at selectively treating either the mother or the fetus. The transplacental transfers of fluorescently (Alexa 488) tagged PAMAM dendrimer (16 kDa) and antipyrine (188 Da) from maternal to fetal circulation were measured using HPLC/dual UV and fluorescent detector (sensitivity of 10 ng / mL for dendrimer and 100 ng /mL for antipyrine respectively). C max for the dendrimer-Alexa (DA) in maternal perfusate (T max = 15min) was 18 times higher than in the fetal perfusate and never equilibrated with the maternal perfusate during 5.5 hours of perfusion (n=4). DA exhibited a significant but low transplacental transport of ~2.26 ± 0.12 μg / mL during 5.5 hours, where the mean transplacental transfer was 0.84 ±0.11 % of the total maternal concentration and the feto-maternal ratio as percent was 0.073% ± 0.02. The biochemical and physiological analysis of the placentae perfused with DA demonstrated normal function throughout the perfusion. The immunofluorescence histochemistry confirmed that the biodistribution of DA in perfused placenta was sparsely dispersed, and when noted was principally seen in the inter-villous spaces and outer rim of the villous branches. In a few cases, DA was found internalized and localized in nuclei and cytoplasm of syncytiotrophoblast and inside the villous core; however, DA was mostly absent from the villous capillaries. In conclusion, the PAMAM dendrimers exhibited a low rate of transfer from maternal to the fetal side across the perfused human placenta, which is similar to other investigations of large macromolecules, eg., IgG. These overall findings suggest that entry of drugs conjugated to polymers, i.e., dendrimers, would be limited in their transfer across the human placenta when compared to smaller drug © 2010 Elsevier B.V. All rights reserved. * Corresponding author: Rangaramanujam M. Kannan, Department of Chemical Engineering and Material Science, Wayne State University, Detroit, Michigan 48202; rkannan.wsu@gmail.com. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscr...

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“…Of significance, the transfer of IgG occurs only across the visceral yolk sac in the rodent and rabbit (Miller et al, 1976; Ross & Boroviak, 2020). In the context of studying teratogenesis in multiple species, these relationships between the yolk sac and the chorioplacenta can play fundamentally different roles, for example, immunoglobulin and vitamin transfer (Polliotti, Panigel, Miller, 1997; Ng, Miller, Catus, 1981; Perez D'Gregorio, R, Miller, 1998).…”

Section: Development and Structure Of The Visceral Yolk Sac In Rodentsmentioning

confidence: 99%

Yolk sac development, function and role in rodent pregnancy

Ornoy

Miller

2023

Birth Defects Research

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During the early phases of embryonic development, the yolk sac serves as an initial placenta in many animal species. While in some, this role subsides around the end of active organogenesis, it continues to have important functions in rodents, alongside the chorio‐allantoic placenta. The yolk sac is the initial site of hematopoiesis in many animal species including primates. Cells of epiblastic origin form blood islands that are the forerunners of hematopoietic cells and of the primitive endothelial cells that form the vitelline circulation. The yolk sac is also a major route of embryonic and fetal nutrition apparently as long as it functions. In mammals and especially rodents, macro and micronutrients are absorbed by active pinocytosis into the visceral yolk sac, degraded and the degradation products (i.e., amino acids) are then transferred to the embryo. Interference with the yolk sac function may directly reflect on embryonic growth and development, inducing congenital malformations or in extreme damage, causing embryonic and fetal death. In rodents, many agents were found to damage the yolk sac (i.e., anti–yolk sac antibodies or toxic substances interfering with yolk sac pinocytosis) subsequently affecting the embryo/fetus. Often, the damage to the yolk sac is transient while embryonic damage persists. In humans, decreased yolk sac diameter was associated with diabetic pregnancies and increased diameter was associated with pregnancy loss. In addition, culture of rat yolk sacs in serum obtained from pregnant diabetic women or from women with autoimmune diseases induced severe damage to the visceral yolk sac epithelium and embryonic malformations. It can be concluded that as a result of the crucial role of the yolk sac in the well‐being of the early embryo, any damage to its normal function may severely and irreversibly affect further development of the embryo/fetus.

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Free vitamin B12 and transcobalamin II-vitamin B12 complex uptake by the visceral yolk sac of the sprague-dawley rat: Effect of inhibitors

Cited by 7 publications

References 39 publications

Rat transcobalamin: cloning and regulation of mRNA expression

Rat transcobalamin: cloning and regulation of mRNA expression

Transfer of PAMAM dendrimers across human placenta: Prospects of its use as drug carrier during pregnancy

Yolk sac development, function and role in rodent pregnancy

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