Intestinal Permeability and Its Role in Disease

Journal of Biomedical Therapy 2009 ) Vol. 3, No. 2 The mucous membranes of the GI tract also provide compartmentalization, protecting the relatively fragile, homeodynamic internal milieu from the relatively harsh environment of the intestinal lumen. Mucosal membranes include many different structures and cells with unique roles in maintaining the physical, chemical, and immunological barrier functions. Another major function of the GI tract is immunity. The epithelial cells of the GI tract provide the first line of defense, protecting us from the potentially dangerous or foreign substances brought into our body via our food and drink. Furthermore, most pathogenic microbes, including many medically important viruses, must cross a mucosal barrier to cause disease. It is estimated that up to 80% of the immune system cells are initiated in the GI tract or spend a good portion of their life there. The gut-associated lymphatic system (GALT) is part of an interdependent mucosal immune system termed the mucosa-associated lymphatic system (MALT). Immunocompetent cells that develop in the GALT are transported via the lymphatic system to the circulatory system to be carried to other mucous membranes, such as the respiratory and urogenital tracts, to provide protection. This interdependence between all mucous membranes in the body is important because it means that by using bioregulatory medicines to restore integrity in the GI tract, we can influence the overall immune system and general health. The immunological barrier function is a very dynamic and complex one, with roles not only in protection from substances that are foreign and/or potentially dangerous but also in tolerance to commensal microflora and the nutrients that are digested and absorbed to maintain normal body functions (Figure). In the healthy GI tract, with intact mucous membranes, tolerance is the predominant immunological function. Therefore, we do not react to the daily nutrients that we need to support our physiological functions. If the GI tract barrier is compromised, there is a breakdown in tolerance, leading to increased reactivity, chronic activation of immune system cells, and production of cytokines that can have localized and systemic effects. Some of the more common diseases associated with a breakdown in the integrity of the GI tract include the inflammatory bowel diseases and certain autoimmune diseases, such as ankylosing spondylitis, IgA nephropathy and multiple sclerosis, type 1 diabetes mellitus, and autism. Other conditions associated with a hyperpermeable GI tract include congestive heart failure, chronic venous insufficiency and the development of leg ulcers, major depressive disorder, chronic fatigue immune deficiency syndrome, gallstones, and progression of human immunodeficiency virus (HIV) infection. The documented relationship between a “leaky gut” and so many important diseases, as described, speaks to the importance of medical interventions that can safely and effectively promote healing in a timely manner. This article will describe Intestinal Permeability and Its Role in Disease