Caco-2 Cell Monolayers as a Model for Drug Transport Across the Intestinal Mucosa
Human colon adenocarcinoma (Caco-2) cells, when grown on semipermeable filters, spontaneously differentiate in culture to form confluent monolayers which both structurally and functionally resemble the small intestinal epithelium. Because of this property they show promise as a simple, in vitro model for the study of drug absorption and metabolism during absorption in the intestinal mucosa. In the present study, the transport of several model solutes across Caco-2 cell monolayers grown in the Transwell diffusion cell system was examined. Maximum transport rates were found for the actively transported substance glucose and the lipophilic solutes testosterone and salicyclic acid. Slower rates were observed for urea, hippurate, and saliylate anions and were correlated with the apparent partition coefficient of the solute. These results are similar to what is found with the same compounds in other, in vivo absorption model systems. It is concluded that the Caco-2 cell system may give useful predictions concerning the oral absorption potential of new drug substances.
[Show abstract] [Hide abstract] ABSTRACT: The release of wheat gluten exorphins (GEs) A5, A4, B5, B4, C5, Gd-7 and dGd-7 during in vitro gastrointestinal digestion (GID) of bread and pasta samples has been investigated by UPLC/ESI-HRMS. The GEs that survived in vitro GID were studied for transport studies across monolayers of 70% Caco-2/30% HT-29 co-culture grown on semi-permeable membranes, used as a model of the human intestinal epithelium. Among the GEs, only the peptides A5 and C5 were detected at the end of in vitro GID of bread and pasta samples. Levels of GEs A5 and C5 were in the range 0.747–2.192 mg kg- 1 and 3.201–6.689 mg kg- 1, respectively. The absorption behavior of A5 and C5 was studied in detail using synthetic peptides. The two peptides were susceptible to the action of Caco-2/HT-29 co-culture peptidases, and 3% and 1% of A5 and C5, respectively, added to the apical chamber were transported to the basolateral chamber after 120 min of incubation, without being hydrolysed. Several hydrolytic fragments of both GEs crossed the co-culture layer and were found in the basolateral chamber. For the first time, these results demonstrate that GEs are released during in vitro GID of real wheat-derived foods and highlight the possibility of transport of the GEs A5 and C5 across the human intestinal mucosa.
- "Generally, transepithelial transport of peptides is studied by in vitro experiments using cell cultures. Caco-2 cells is a commonly accepted in vitro model of intestinal epithelium because they share some important characteristics of mature small intestinal cells, such as intercellular tight junctions, intestinal enzymes, and active (peptide) transport systems (Fogh, Fogh, Orfeo, & 221–226, 1977; Hilgers, Conradi, & Burton, 1990; Pinto et al., 1983; Uchida et al., 2015; Wilson et al., 1990). Nonetheless, this in vitro cell model suffers limitations mainly related to the absence of a mucus layer and low expression of uptake transporters (Mahler, Shuler, & Glahn, 2009; Satake et al., 2002). "
[Show abstract] [Hide abstract] ABSTRACT: Total flavones of Hippophae rhamnoides L. (TFH) are extracted from the widely distributed thorny bush Sea buckthorn (Hippophae rhamnoides L.). Isorhamnetin (IS) is one of the representative ingredients in TFH. In this study, the absorption properties of IS in TFH and its pure form were compared through transepithelial transport and cellular uptake experiments in a Caco-2 cell model. Our results show that the absorption properties of IS in TFH and its pure form were remarkably different: (1) Both PappAB and PappBA of IS in TFH were dramatically increased compared with those of IS pure form; consequently, its Pratio was 2.3-fold higher than that of IS; (2) Both the accumulation and efflux of IS in TFH were significantly enhanced compared with the single compound. One likely reason for these differences is that the multiple components in TFH significantly down regulated the mRNA expression level of MRP2, which lead to a decrease in the protein level of MRP2, based on western blotting and RT-PCR assays. This study highlights the significant differences in the absorption properties of flavonoid components in different forms and the potential multi-component interactions in TFH. Copyright © 2015. Published by Elsevier B.V.
- "To date, there are no studies comparing the absorption properties of IS in TFH and its pure form and elucidating the possible interaction mechanism. The Caco-2 cell line was derived from human colorectal carcinoma , and its monolayers were a well-accepted model of human intestinal absorption because they could exhibit many morphological and functional characteristics with mature enterocytes (Artursson and Karlsson, 1991; Hilgers et al., 1990 ). Thus, the present study characterizes the absorption properties of IS in TFH and its pure form through transepithelial transport and cellular uptake experiments using a Caco-2 cell model. "
[Show abstract] [Hide abstract] ABSTRACT: ABSTRACT Bioactive peptides are food derived components, usually consisting of 3-20 amino acids, which are inactive when incorporated within their parent protein. Once liberated by enzymatic or chemical hydrolysis, during food processing and gastrointestinal transit, they can potentially provide an array of health benefits to the human body. Owing to an unprecedented increase in the worldwide incidence of obesity and hypertension, medical researchers are focusing on the hypotensive and anti-obesity properties of nutritionally-derived bioactive peptides. The role of the renin-angiotensin system has long been established in the aetiology of metabolic diseases and hypertension. Targeting the renin-angiotensin system by inhibiting the activity of angiotensin-converting enzyme and preventing the formation of angiotensin II can be a potential therapeutic approach to the treatment of hypertension and obesity. Fish-derived proteins and peptides can potentially be excellent sources of bioactive components, mainly as a source of ACE inhibitors. However, increased use of marine sources, poses an unsustainable burden on particular fish stocks, so, the underutilised fish species and by-products can be exploited for this purpose. This paper provides an overview of the techniques involved in the production, isolation, purification and characterization of bioactive peptides from marine sources, as well as the evaluation of the ACE inhibitory activity and bioavailability.
- "Caco-2 cell monolayers, derived from a human colon carcinoma , exhibit characteristics that resemble the human intestinal epithelial cells, such as a polarized monolayer, welldefined brush border on the apical surface and inter-cellular junctions. This cellular model has been used to assess transport of the bioactive compound in both directions (apical to basolateral and vice-versa) across the cell monolayer (Hilgers et al., 1990; Le Ferrec et al., 2001). Peptides are rapidly metabolized by amino-peptidases into their constituent amino acids. "