Colonic mucosa

Although vitamin K is a fat soluble vitamin, only little stores are found in the body which have to be refilled permanently via dietary input. The role of vitamin K derived from bacteria in the colon is controversely discussed, as the concentration of biliary acids for the resorption the fatsoluble vitamin K is very low in the colon. In addition, only diseases of the small intestine lead to a deficit in vitamin K concentration which cannot be restored by K2 production of colonic bacteria. However, watersoluble vitamin Ks can be resorbed by the colonic mucosa. Maybe because of the little stores for vitamin K, the process of vitamin K-dependent carboxylation of proteins is part of a cycle with several steps during which vitamin K normally is regenerated (see Fig. 1) and thus can be used several times. 

SMITH T, MUSK s R and JOHNSON I T (1996) Allyl isothiocyanate selectively kills undifferentiated HT29 cells in vitro and suppresses aberrant crypt foci in the colonic mucosa of rats , Biochem Soc Trans, 24 381S. 

MAJUMDAR A p (1990) Role of tyrosine kinases in gastrin induction of ornithine decarboxylase in colonic mucosa. Am J Physiol. 259 (4 Ptl) G626-G630. 

Inauen, W., Bilzer, M., Rowedder, E., Halter, F. and Lauterbutg, B.H. (1988). Decreased gjutathione (GSH) in colonic mucosa of patients with inflammatory bowel disease mediated by oxygen free radicals Gastroenterology 94, A199. 

Christl SU, Eisner HD, Dusel G, et al. 1996. Antagonistic effects of sulfide and butyrate on proliferation of colonic mucosa—A potential role for these agents in the pathogenesis of ulcerative colitis. Dig Dis Sci 41 2477-2481. 

Normal colon mucosa versus colorectal carcinoma 226... 

Stulik J et al. Protein abundance alterations in matched sets of macroscopically normal colon mucosa and colorectal carcinoma. Electrophoresis 1999 20 3638-3646. 

Shigella incidence highest in children 1-5 years of age 24-72h watery at the onset and may evolve to bloody diarrhea or dysentery invasion and destruction of the distal ileal and colonic mucosa - release of cytokines - PMN mucosal infiltration... 

Lopez-Oliva ME, Agis-Torres A, Garcia-Palencia P, Goni I and Munoz-Martinez E. 2006. Induction of epithelial hypoplasia in cecal and distal colonic mucosa by grape antioxidant dietary fiber. Nutr Res... 

Fiber, in the form of soy polysaccharides, has been added to several EN formulations. In addition to providing an excellent energy source, potential benefits include trophic effects on colonic mucosa, promotion of sodium and water absorption, and regulation of bowel function. 

J. Holm, S. I. Hansen, M. Hoier-Madsen, K. Sondergaard, and M. Bzorek. The high-affinity folate receptor of normal and malignant human colonic mucosa. ABM IS 102 828-836 (1994). 

Ramakrishna BS, Roberts-Thomson IC, Pannall PR, et al. 1991. Impaired sulphation of phenol by the colonic mucosa in quiescent and active ulcerative colitis. Gut 32 46-49. 

Drug molecules that have traversed the physieal and enzymatic barriers of the colonic mucosa may enter the blood-eapillary bed or the lymphatic sinuses. Intact drug that reaches the venous capillaries from the submucosa is transported to the liver via the hepatic-portal system where they may undergo significant metabolism. On the other hand, uptake into the lymphatie sinuses of the colon results in direct delivery into the systemic circulation that causes less metabolic breakdown of the absorbed drug [3]. 

The colonic mucosa resembles the small intestinal mucosa with respect to the spectrum of metabolizing enzymes [26], However, the total metabolic capacity of the colonic wall is inferior, since the mucosal mass in the lower part of the intestine is several times smaller than in the upper part. But this may be more than offset by the high metabolic capacity foimd in the gut flora in the large intestine. 

CEA is a heterogeneous glycoprotein of molecular weight 180,000 kDa. It was originally considered to be specific for colon carcinoma however, it is now known to be expressed in many different tumors and fetal tissues as well as adult colonic mucosa (27). Table 6 shows a summary of CEA reactivity in epithelial tumors. 

Colon [biopsies from colonic mucosa (nontumour tissue) of patients with colon cancer] Increased resistance to DOC-induced apoptosis of colonic epithelial cells of cancer patients or increased expression of anti-apoptotic protein Bc1-xl. 1,27,28,52,127... 

In humans, epithelial cells of the flat non-neoplastic colonic mucosa of individuals with colon cancer often have reduced capacity to undergo DOC-induced... 

C. M. Payne, C. Bernstein and H. Bernstein, Field change of apoptosis resistance in colonic mucosa of patients with colorectal carcinoma, J. Clin. Path., 2007, Electronic letters published (5 February, 2007). 

K. La Ferla, D. Seegert and S. Schreiber, Activation of NF-kappaB in intestinal epithelial cells by E. coli strains isolated from the colonic mucosa of IBD patients, Int. J. Colorectal Dis., 2004, 19(4), 334. 

H. S. Samaha, C. Bernstein, C. M. Payne, H. Garewal, R. Sampliner and H. Bernstein, Bile salt induction of apoptosis in goblet cells of the normal human colonic mucosa relevance to colon cancer, Acta Microsc., 1995, 4, 43. 

Melanosis coll Melanosis coll is a darkened pigmentation of the colonic mucosa resulting from chronic use of anthraquinone derivatives (casanthrol, cascara sagrada, senna). 

Yet when p-carotene is coated with pectin (edible coating), the pectin prevents p-carotene — or other carotenoids as well as fat-soluble compounds — from being absorbed in the upper parts of the small intestine. As a consequence, these coated compoimds can be transported via the chymus to the colon, where the pectin is broken down to short-chain fatty acids by bacteria. These fatty acids play an important role as growth regulators of the colonic mucosa cells. At the same time, the active agents, such as p-carotene, are released and can then be absorbed by the mucosa. 

The mechanisms of action of many laxatives are not well understood due to the complex factors that affect colonic function. However three general mechanisms can be recognized (1) fluid retention in colonic contents thereby increasing bulk, (2) direct or indirect effects on the colonic mucosa to decrease net absorption of water and NaCl and (3) increase of intestinal motility. 

Sulfasalazine is composed of sulfapyridine and 5-ASA molecules linked by an azo bond. Sulfapyridine has no effect on the inflammatory bowel disease, and instillation of this agent into the colon does not heal colonic mucosa. It is, however, responsible for most of sulfasalazine s side effects, including sulfa allergic reactions. 5-ASA, the active metabolite, may inhibit the synthesis of mediators of inflammation. 

Sulfasalazine treatment results in an 85% remission rate in mild to moderate ulcerative colitis. Termination of therapy leads to an 80% relapse within the next year. In Crohn s disease, sulfasalazine acts primarily on involved colonic mucosa, although remission of ileal disease also has been reported. The National Cooperative Crohn s Disease Study found sulfasalazine to be better in the treatment of colonic disease, while corticosteroids were judged better in the treatment of small bowel disease. Since sulfasalazine does not prevent relapse of Crohn s disease once remission is achieved, maintenance therapy is not characteristically used. 

HVHO Kanauchi O., T. Iwanaga, A. Andoh, et al. Dietary fiber fraction of germinated barley foodstuff attenuated mucosal damage and diarrhea, and accelerated the repair of the colonic mucosa in an experimental colitis. J Gastroenteol Hepatol 2001 16(2) 160-168. 

Lipkin, M., Uehara, K., Winawer, S., Sanchez, A., Bauer, C., Phillips, R., Lynch, H.T., Blattner, W.A., and Fraumeni, J.F., Seventh-Day Adventist vegetarians have a quiescent proliferative activity in colonic mucosa, Cancer Lett., 26, 139, 1985. 

Human colonic epithelial cells synthesize LTB4, a chemoattractant for neutrophils. The colonic mucosa of patients with inflammatory bowel disease contains substantially increased amounts of LTB4. 

Lecluyse EL, Sutton SC, Fix JA. In vitro effects of long-chain acylcamitines on the permeability, transepithelial electrical resistance and morphology of rat colonic mucosa. J Pharmacol Exp Ther 1993 265 955-962. 

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