Nutrient Pharmacotherapy for Gut Mucosal Diseases

The development of specific nutrients for treatment of gastrointestinal diseases represents a novel approach to pharmacotherapy. Gut dysfunction may respond to either direct use of nutrients that have pharmacologic effects or indirect application of nutrients to enhance the response to medication. Additionally, drugs may enhance nutrient absorption. Preservation and maintenance of gut structure and function is crucial to health. Intestinal cells proliferate, differentiate, and have the greatest rate of turnover in the body and high-energy expenditure. Luminal nutrients directly affect mucosal growth by providing nutrition and indirectly by stimulating release of gastrointestinal peptides and hormones and regulating blood flow. Physical stress, including surgery, burns, fever, and sepsis, especially in association with inadequate oral nutrition, has a negative impact on nitrogen balance and may affect caloric needs. To confound further the need for balanced energy expenditure, elimination of oral intake has a deleterious effect on gut structure, reduces gut mass, and decreases production of gut hormones.22 The frequent prescription of broad-spectrum antibiotics may also diminish endogenous energy sources. Their use reduces fermentation of undigested dietary polysaccharides by colonic flora and thus decreases production of the colonic fuel, short-chain fatty acids (SCFA). Increased protein catabolism and deficiency of intestinal nutrients have significant harmful effects on the clinical outcome of the compromised patient. The consequences of these changes include prolonged hospitalization, reduced wound healing, increased risk of infection, impaired immunity, and generalized weakness. Hence, there is an ongoing pursuit to ascertain which specific nutrients have the capability to prevent or reverse these effects and thus promote healing. This article briefly reviews both animal and human studies concerning the nutritional pharmacotherapeutic effects of glutamine; the growth factors, growth hormone, insulin-like growth factor-1 (IGF-1), and epidermal growth factor (EGF); and SCFA. Emphasis is placed on the potential clinical application of these agents. It is acknowledged that the established clinical utility of these nutrient-pharmacotherapeutic factors is still evolving and a considerable amount of data is obtained from animal studies.