Enterocytes proliferation

The small intestinal mucosa tends to maintain a constant morphological appearance, despite the fact that there is a rapid renewal of cells in intestinal crypts and rapid transit of cells up the intestinal villi. Among those factors which are reported to influence morphological structure and the rates of enterocyte proliferation, differentiation and extrusion, are physical trauma[l] changes in gut flora[2] hormones[3] the state of nutrition and feeding patterns [4] and bile acid concentration[5]. 

Figure 4.15 k summary of the fate of nucleosides that are produced from RNA digestion in the lumen of the intestine. The nucleosides produced from RNA in the lumen are absorbed by the enterocytes and then transported from the intestine into the blood from where they are taken up by cells (especially proliferating cells, e.g. in the bone marrow) to form nucleotides for DNA and RNA synthesis. (See Chapter 10) NTP is nucleoside triphosphate. 

Loss of hair results from injury to hair follicles gastrointestinal disturbances, such as diarrhea, from inadequate replacement of enterocytes whose life span is limited to a few days nausea and vomiting from stimulation of area postrema chemoreceptors (p. 330) and lowered resistance to infection from weakening of the immune system (p. 300). In addition, cytostatics cause bone marrow depression. Resupply of blood cells depends on the mitotic activity of bone marrow stem and daughter cells. When myeloid proliferation is arrested, the short-lived granulocytes are the first to be affected (neutropenia), then blood platelets (thrombopenia) and, finally, Liillmann, Color Atlas of Pharmacology... 

In vivo studies using mouse models have proved that curcumin modifies apoptosis resistance, leading to the inhibition of tumor formation and the prevention of adenoma development in the intestinal tract. The chemopreven-tive effect of curcumin for intestinal tumors in Min/+ mice was investigated. A dietary level of 0.15% curcumin decreased tumor formation in Min—/— mice by 63%. Examination of intestinal tissue from the treated animals showed the tumor prevention by curcumin was associated with increased enterocyte apoptosis and proliferation. Curcumin also decreased expression of the oncoprotein (S-catenin in the erythrocytes of the Min/+ mouse, an observation previously associated with an antitumor effect. Curcumin enhanced PhlP-induced apoptosis and inhibited PhIP-induced tumorigenesis in the proximal small intestine of Ape (min) mice. Experiments performed on intestinal tumors in C57BL/6J-Min/+ (Min/+) mice demonstrated that curcumin has a regulatory role in lymphocyte-mediated immune function [Churchill et al., 2000]. Furthermore, levels of COX-2 protein expression have been found to reflect the retardation of adenoma development in mouse intestines after treatment with curcumin [Tunstall et al., 2006]. 

Increases insulin secretion Enterocyte-specific growth hormone Cell proliferation and differentiation Unclear... 

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