Cell cultures placental

Human blood or human blood-derived products, including placental blood-derived products, animal-derived procoagulant products and animal- or cell culture-derived hemoglobin-based products intended to act as red blood cell... 

The degree of exposure of the fetus to a particular substance can be best assessed in human subjects, but concerns of fetal safety have restricted the use of this approach. Moreover, clinical studies cannot elucidate the various mechanisms that contribute to transplacental transport of a particular compound. There are many structural differences between the human placenta and the placenta of other mammalian species, which complicates extrapolation of data obtained from in vivo animal models to humans [7], Thus, several ex vivo and in vitro techniques have been developed to study the placental role in drug transfer and metabolism during pregnancy and there are some excellent articles that discuss these systems in detail [7], Both isolated tissues and various cell culture techniques are currently in use and these have been summarized below. 

R.G. Richards, S.M. Hartman, and S. Handwerger. Human cytotrophoblast cells cultured in maternal serum progress to a differentiated syncytial phenotype expressing both human chorionic gonadotropin and human placental lactogen. Endocrinology. 135 321-329 (1994). 

Cell culture or cellular fractions (e.g., human placental microsomes)... 

So far the only well-characterized uncompetitive inhibitor is L-phenyl-alanine, shown to be uncompetitive for intestinal (180) and placental phosphatases (42). By contrast, D-phenylalanine has no inhibitory effect. The L isomer apparently acts by preventing the breakdown of phosphoryl phosphatase (170), possibly by blocking the acceptor site mentioned in Section III,D,4. A list of concentrations required to produce 50% inhibition of a wide variety of phosphatases showed that all the enzymes were affected though there was a spread in susceptibilities from 0.8 mM for HeLa cell culture phosphatase to 26 mM for mouse intestinal phosphatase... 

The purpose of this chapter is to present overviews of a selection of the major endothelial and epithelial barriers to drug delivery for which there are either primary culture or cell line systems that recapitulate the characteristics of the in vivo barrier. Our objective is to define some general characteristics of cell culture models and highlight the more commonly applied primary cell cultures and cell lines in use today. Specifically, we focus on cell culture models for the intestinal epithelium, blood-brain barrier, pulmonary and nasal epithelium, ocular epithelium, placental barrier, and renal epithelium. Renal epithelium was included here primarily because some cell lines derived from this tissue [e.g., Madin-Darby canine kidney cells (MDCK)] are often used as surrogates for other barriers by pharmaceutical scientists. We have arbitrarily chosen to exclude the skin and liver from the scope of this overview. However, it should be noted that hepatocyte cell culture models, for example, are becoming more widely available and have been the subject of recent reviews.1,2... 

By comparison with other tissues discussed in this review, the identification of representative cell culture models of the placental barrier for chug delivery applications is more recent. Prior to the development of cell culture techniques, isolated tissues and cells of human placenta were used these methods have been described... 

Guyda HJ. Mathieu L. Lai W. et al. 1990. Benzo(a)pyrene inhibits epidermal growth factor binding and receptor autophosphorylation in human placental cell cultures. Mol Pharmacol 37(2) 137-143. 

The nephrotoxicity of 16 continues to generate considerable interest. Orellanine was highly toxic to mice (LD50 = 12.5 mg/kg i.p.)[101] and caused interstitial nephritis and tubular necrosis in mouse kidney [102], A summary of 16-induced changes in renal function and morphology has been reported [103]. In LLC-PKi renal epithelial cell cultures, 16 decreased the activity of alkaline phosphatase and lactate dehydrogenase, and decreased the incorporation of H-leucine and H-thymidine [104]. Orellanine was a noncompetitive inhibitor of renal alkaline phosphatase, but a competitive inhibitor of the intestinal and placental enzymes [105]. In canine kidney MDCK cell cultures, 16, or a metabolite of 16, inhibited protein, RNA and DNA synthesis [106]. 

Xu et al. [76] have showed that human embryonic stem cells by treatment with bone morphogenetic protein-4 can be driven to differentiate into tro-phoblasts which have the ability to syncytialize and form confluent mono-layers. The differentiated cells express a number of trophoblast markers and secrete placental hormones and thus may provide an alternative placental model. Under the culture conditions used, however, the cells propagated poorly. 

Amniocentesis conducted between 15 and 21 weeks gestation yields cells capable of growth in culture. These can be easily used to extract DNA (or RNA) and subjected to analysis. This tissue is less subject to concern with maternal cell contamination than CVS, but it can still present diagnostic problems, such as confined placental mosaicism. The level of such problems can sometimes be assessed using... 

Twenty years ago, a high-affinity-binding site for uPA was demonstrated on the surface of peripheral blood monocytes and cultured cells of the human histiocytic lymphoma cell line, U937 [46]. The expression of uPAR on the cell surface of many cell types has since then been demonstrated, including a variety of neoplastic cell lines as well as nonneoplastic cells such as neutrophils, macrophages, keratinocytes, placental trophoblasts, endothelial, and smooth muscle cells [7, 33, 47-51]. The human uPAR gene has been mapped to chromosome 19ql.3 [52]. 

Calcidiol la-hydroxylase is not restricted to the kidney, but is also found in placenta, bone cells (in culture), mammary glands, and keratinocytes. The placental enzyme makes a significant contribution to fetal calcitriol, but it is not clear whether the calcidiol 1-hydroxylase activity of other tissues is physiologically significant or not. Acutely nephrectomized animals given a single dose of calcidiol do not form any detectable calcitriol, but there is some formation of calcitriol in anephric patients, which increases on the administration of cholecalciferol or calcidiol. However, thus extrarenal synthesis is not adequate to meet requirements, so that osteomalacia develops in renal failure (Section 3.4.1). The enzyme is inhibited, or possibly repressed, by strontium ions this is the basis of strontium-induced vitamin D-resistant rickets, which responds to the administration of calcitriol or la-hydroxycalciol, but not calciferol or calcidiol (Omdahl and DeLuca, 1971). 

OH)D-la-hydroxylase is found in the inner mitochondrial membrane of the cells lining the proximal convoluted renal tubules. It is a mixed-function oxidase that requires molecular oxygen, a flavoprotein, a ferredoxin, and a cytochrome P-450 for activity. It is inhibited by carbon monoxide. Placental tissue contains la-hydroxylase activity, as do cultured bone cells and macrophages. This finding is of questionable importance under most circumstances, however, since l,25-(OH)2D is not present in significant amounts in nonpregnant, nephrectomized animals. 

Guyda HJ. 1991. Metabolic effects of growth factors and polycyclic aromatic hydrocarbons on cultured human placental cells of early and late gestation. J Clin Endocrinol Metab 72(3) 718- 723. 

All different types of experimental systems, from isolated cells to whole tissue perfusion, have been used to. study the placenta (Table 4), Since placenta is anatomically complex and highly polarized in its functions (Ganapathy ei ai, 2000 Cariappa et al 2003), the method to be u,sed has to be carefully considered based on the purpose of the studies. For a complete view of placental transporters (Ganapathy el al, 2000 Cariappa et al., 2003), it may be necessary to use more than one experimental system. Hcikkila and coworkers (2002) demonstrated the integration of a gene construct in placental cells by combining placental pcrfu.sion and explant culture thereafter,... 

Explant cultures have also been used to isolate specific cell types from the placenta, Leik ei ai (2004) grew arterial smooth muscle cells from cultured small pieces of placental arteries from chorionic plate. Within 1 week, cells with uniform morphology expressing proteins similar to human aonic smooth muscle cells but clearly different from fibroblasts or endothelial cells grew- out of the expiants. These cells can be used as a general model for human arterial smooth muscle cells (I eik et ai, 2004),... 

Placental venous endothelial cells have different characteristics depending on which part of the vasculature they have been isolated from, Tsolation, purification, and culture of primary human placental endothelial cells (HPECs) from microvessels on the venous side were reported by Jinga and coworkers (2(KX)). To gain pure cultures of HPECs, trypsin perfusion of the placental cotyledon was followed by Percoll gradient and sequential trypsinization of cultures, The,se cultures represent pure HPEC form microvessels by expressing typical patterns of markers ACE, von Willcbrand factor (typi-... 

Petraglia, F., Sutton, S., and Vale, W. (1989). Neurotransmitiers and peptides modulate the release of immunoreactive corticotropin-releasing factor from cultured human placental cells. Am. J. Oh.stei. Gynecol 160,247-251. 

In addition to iodothyronine 5-deiodinase activity, placental hoanogenates and cultures of human chorionic decidual cells contain T4 and rT3 5 -deiodinase activity but this activity is far less than that observed for 5-deiodinase. 

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