| Popis: |
The human intestinal mucosa is lined by a single layer of epithelial cells covering a complexly folded area of up to 200 m2. Regarding transport, this epithelium fulfills two contrasting functions: (1) absorption and secretion of ions, enzymes, nutrients, and water, and (2) formation of a selective barrier between the circulation and the gut lumen which prevents, e.g., uptake of infectious or immunological relevant solutes. Almost all intestinal diseases affect, or are affected by, transepithelial transport or paracellular barrier functions. An impaired intestinal barrier is preferably caused by modified tight junctions or altered expression of their proteins. This has two functional effects: (1) ions and water diffuse into the intestinal lumen and cause a leak-flux diarrhea, and (2) uptake of luminal pathogens induces an immune response and maintains an inflammatory process. In the second part of this chapter, intestinal diseases are described in pathophysiological and clinical detail and are grouped in three categories. The first are the inflammatory bowel diseases Crohn’s disease, ulcerative colitis, and microscopic colitis. Another category are the gluten-sensitive autoimmune disease celiac disease and the non-celiac gluten-sensitivity. A final group contains diseases caused by bacterial infection, giardia lamblia infection and Whipple’s disease. |
