In vitro cell culture

In this in vitro system, the presence of serum in cell culture medium is not necessary, but the type of transwell is important (the total amount of H-triglycerides secreted was two-fold higher when using 3 pm versus 1 pm pore size transwells), and oleic acid supplementation is required for the formation and secretion of CMs as well as the transport of 3-carotene through Caco-2 cells. Finally, the presence of Tween 40 does not affect CM synthesis and secretion in this in vitro cell culture system. Thus, CMs secreted by Caco-2 cells were characterized as particles rich in newly synthesized H-triglycerides (90% of total secreted) containing apolipoprotein B (30% of total secreted) and H-phospholipids (20% of total secreted) and with an average diameter of 60 nm. These characteristics are close to those of CMs secreted in vivo by enterocytes. ... 

Okai, Y. and Higashi-Okai, K., Possible immunomodulating activities of carotenoids in in vitro cell culture experiments, Int. J. Immunopharm., 18, 753, 1996. 

Astashkina, A., Mann, B. Grainger, D. W. A critical evaluation of in vitro cell culture models for high-throughput drug screening and toxicity. Pharmacol. Ther. 134, 82-106 (2012). 

Kim DC, PS Burton, RT Borchardt. (1993). A correlation between the permeability characteristics of a series of peptides using an in vitro cell culture model (Caco-2) and those using an in situ perfused rat ileum model of the intestinal mucosa. Pharm Res 10 1710-1714. 

Gumbleton, M. and K. L. Audus. Progress and limitations in the use of in vitro cell cultures to serve as a permeability screen for the blood-brain barrier, J. Pharm. Sci. 2001, 90, 1681-1698... 

Herrera-Ruiz, D., et al. Spatial expression patterns of peptide transporters in the human and rat gastrointestinal tracts, Caco-2 in vitro cell culture model, and multiple human tissues. AAPS PharmSci. 2001, 3, E9. 

When applying any of these models it is crucial to understand the main transport mechanisms as well as the metabolic route and characterization of the activity of the transporter/enzyme involved. It is well recognized that the activities of carrier-mediated processes in Caco-2 cells are considerably lower than in vivo [20, 42, 48] therefore, it is crucial to extrapolate in vitro cell culture data to the in vivo situation with great care [18, 20, 42, 48], This is especially important when carrier-mediated processes are involved, as evidenced by a recent report which showed significant differences in gene expression levels for transporters, channels and metabolizing enzymes in Caco-2 cells than in human duodenum [48], If an animal model is used, then potential species differences must also be considered [18, 20, 45],... 

Fu et al. (2002) report the optimization of a fabrication procedure for microspheres based on the poly( anhydride-co-ether) P(SA-EG). The microspheres are fabricated by solvent removal process that produces a porous structure with densities in the range of 0.344 and 0.077 g cm-3 and sizes that are optimized for delivery to the deep lung by inhalation (Fu et al., 2002). An appropriate in vitro cell culture model for characterization of the particle-epithelia system was also developed (Fiegel et al., 2003). 

Annaert P, Kinget R, Naesens L, de Clercq E, Augustijns P (1997) Transport, uptake, and metabolism of the bis(pivaloyloxymethyl)-ester prodrug of 9-(2-phosphonylmethoxyethyl)adenine in an in vitro cell culture system of the intestinal mucosa (Caco-2). Pharm Res 14 492-496. 

In vitro cell culture models of human nasal epithelium based on primary culture technologies have proven to be extremely useful for mechanistic studies of nasal epithelial permeability and drug absorption [13]. However, efforts... 

Ethical issues as well as difficulty in obtaining enough human nasal tissue specimens have called for the need to use alternative in vitro and in vivo methods. Various in vivo animal models and in vitro excised tissue models have been described in the literature for nasal drug transport studies. However, due to the difficulty in both controlling the experimental conditions in in vivo animal models and obtaining intact excised tissue samples, in vitro cell culture models are also being actively developed. 

U. Werner and T. Kissel. In-vitro cell culture models of the nasal epithelium A comparative histochemical investigation of their suitability for drug transport studies. Pharm Res 13 978-988 (1996). 

T. Kissel and U. Werner. Nasal delivery of peptides An in vitro cell culture model for the investigation of transport and metabolism in human nasal epithelium. J Control Release 53 195-203 (1998). 

Table 10.2 Expression profiles of phase II metabolic enzymes in human bronchial mucosa and in vitro cell culture models.

Goskonda VR, Khan MA, Hutak CM, Reddy IK. Permeability characteristics of novel mydriatic agents using an in vitro cell culture model that utilizes SIRC rabbit comeal cells. J Pharm Sci 88 180-184 (1999). 

The vast majority of research focused on selenium in biology (primarily in the fields of molecular biology, cell biology, and biochemistry) over the past 20 years has centered on identification and characterization of specific selenoproteins, or proteins that contain selenium in the form of selenocysteine. In addition, studies to determine the unique machinery necessary for incorporation of a nonstandard amino acid (L-selenocysteine) during translation also have been central to our understanding of how cells can utilize this metalloid. This process has been studied in bacterial models (primarily Escherichia colt) and more recently in mammals in vitro cell culture and animal models). In this work, we will review the biosynthesis of selenoproteins in bacterial systems, and only briefly review what is currently known about parallel pathways in mammals, since a comprehensive review in this area has been recently published. Moreover, we summarize the global picture of the nonspecific and specific use of selenium from a broader perspective, one that includes lesser known pathways for selenium utilization into modified nucleosides in tRNA and a labile selenium cofactor. We also review recent research on newly identified mammalian selenoproteins and discuss their role in mammalian cell biology. 

Figure 6.3 Diagram of in vitro cell culture system used in studying bidirectional transport. (Modified from [13]).

The use of in vitro cell culture models for mechanistic studies and as permeability screens for the blood-brain barrier in the pharmaceutical Industry-Background and current status in the drug discovery process. Vascular Pharmacology, 38, 355-364. 

In Vitro Cell Culture Keratinocytes (KC) comprise some 95% of the cells in the... 

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