2005 Annual Report
1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter?
A common dietary problem in Westernized societies is functional deficiencies in trace minerals and vitamins due to poor eating behavior. There are also harmful environmental conditions that contribute trace mineral pollutants and contaminants that compete with essential trace minerals for binding sites on functional proteins. Seventy-six million cases of food-borne illness occur each year in the United States at a cost of $3-7 billion annually, yet it is not clear how important are micronutrients and trace minerals in the prevention of disease of the intestinal track. Basic information on functional deficiencies is best explored through animal models as a vehicle for hypothesis testing of novel strategies and approaches. Mice are an excellent experimental model for testing the role of nutrition on immune function because there is a wide spectrum of reagents for marking and characterizing cells and cell products that regulate immune function, and genetic strains are available or can be created to measure the effect of gene deletions or genetic modifications. Mice will be used as a model to determine how specific nutritional deficiencies in vitamin E (VE) and selenium (Se) affect the intestinal response to inflammation and infection. The overall hypothesis of the proposed studies is that these deficiencies will impair the protective response of the intestine to inflammation or infection orchestrated by distinct cell populations and products that skew the intestinal response towards patterns that are particularly designed to neutralize different classes of pathogens. We hypothesize that these polarized cytokine profiles induce stereotypic alterations in epithelial and smooth muscle cell function that are a critical part of host defense. The studies will focus on two nutrients, Se and VE, known to influence the oxidative status in the gut and to measure the effect of deficiencies in these nutrients on appropriate immunity to infection and inflammation. This work will provide definitive data on the requirements for antioxidants to provide adequate intestinal function to improve immunity and prevent microbial invasion or expansion. Any dietary considerations derived from this research could be used to define a health-promoting diet that would improve resistance or recovery from intestinal infections, have a broad impact on the large number of people affected by these illnesses, and could result in reduced health care costs. The research falls under the Human Nutrition Program (107) and within Action Plan 18.104.22.168 that addresses, "…A continuing need to expand our understanding of the roles nutrients play in maintaining health and to identify those components of foods that are most beneficial. "The research promotes several goals of Action Plan 3.1.1 including,.
1)the need "to establish healthful intakes of specific nutrients" 2)"defining interventions for reducing disease risks" 3)"develop effective strategies, based on the results of sound human nutrition research, to lower the cost of health care by prevention of diseases."
2.List the milestones (indicators of progress) from your Project Plan.
Milestone 1 (12 - 24 months): Identify the mechanisms of local type 1 and type 2 cytokine-dependent alterations in gut function in the colon and small intestine that affect responses to infection.
Milestone 2 (12 - 24 months): The basic model will evaluate parasitic worm infections that invade different regions of the intestine and induce the immune response of interest in the project.
Milestone 3 (24 - 48 months): Determine the impact of specific nutritional deficiencies alone (Se and VE) on baseline levels of cytokines and cytokine receptor expression and on gut function.
Milestone 4 (36 - 48 months): Determine the impact of specific nutritional deficiencies (VE and Se) on immune-induced alterations to microbial pathogens or inflammatory stimuli. Dietary changes will be evaluated to identify those diet/pathogen combinations that demonstrate affects on pathogenicity or infection resolution. Combinations studies will determine the changes in cytokine and receptor patterns that are integral to activating the desired response phenotype.
Milestone 5 (48 - 60 months): The last milestone will determine immune function tied to changes in physiological alterations that affect the infectious agent and the transport of nutrients across the intestinal surface.
Milestone 6 (48 - 60 months): Complete technology transfer.
4a.What was the single most significant accomplishment this past year?
Selenium and vitamin E control distinct components of the protective response to intestinal parasitic infection: Optimal performance of intestinal tissue includes adequate absorption of nutrients and prevention of infection by agents that continually challenge the epithelial cell border. Nutritional deficiencies in Se and VE affect the clearance and pathogenicity of Ribonucleic Acid (RNA) viruses and some protozoan parasites. This observation was extended to study the effect of Se and VE deficiency following exposure to more complex worm parasites that represent pathogens that infect over a quarter of the world's population and stimulate host responses that mimic responses to food allergens. The impact of micronutrient deficiencies on gut function should provide information on mechanisms to control infection and disease from multiple sources. The research showed that deficiencies in Se/VE increased the persistence and intensity of infection by delaying worm expulsion; however, only VE deficiency impaired the normal physiological response involved in worm expulsion indicating that Se and VE affected different mechanisms of action. There is a level of interaction and complexity with these two selected micronutrients that suggest unique pathways that are dependent on adequate dietary intake. This research supports Strategic Plan for Human Nutrition Requirements 22.214.171.124: To develop appropriate animal models that will be used to identify specific biomarkers that are associated with developmental effects or disease prevention. Associated studies supplementing infected animals with Se and VE could limit the severity of infection.
4b.List other significant accomplishments, if any.
Single deficiencies in Se or VE affect intestinal immunity by different mechanisms. The action of Se and VE appear to affect different components of the response that delays worm expulsion; VE but not Se blocks changes in glucose absorption that typically are reduced during worm expulsion. This affect is not related to altered cytokine gene expression and it suggests that a down stream component of cytokine-induced changes in physiological function is affected. Only the type 2 component of the immune response that initiates worm expulsion in the intestine has been examined. Infection with the gram negative bacteria Citrobacter rodentium has been selected to study modulation of type 1 immune response in the colon. The model has been expanded to cover immune-based alterations in intestinal physiology to both bacterial and worm infections in the gut. These studies are unique and should provide information on dietary changes that enhance intestinal health against a broad range of pathogens.
4c.List any significant activities that support special target populations.
This project was approved in March 2004. Initial studies have been shown that Se or VE deficiencies affect the local immune and physiological response to worm infection that results in more severe disease intensity. The target of the deficiency is related to changes in nutrient absorption that have not been previously described. Evaluating bacterial infections in the intestine will determine if Se and VE deficiency affects a broad response pattern to intestinal pathogens.
5.Describe the major accomplishments over the life of the project, including their predicted or actual impact.
This project is derived from studies that demonstrated that deficiencies in Se or VE increased the virulence of coxsackievirus B3 and influenza infections in somatic tissues. Molecular analysis of the viruses isolated from the deficient mice indicated that specific mutations had occurred within the viral genomes that are associated with the increased virulence. Since both Se and VE are important for the antioxidant defense of the host, it is believed that nutrient deficiency-induced oxidative stress is the driving force behind the rapid evolution of these viruses. This is the first attempt to examine changes in oxidative stress in the intestine against intestinal infections.
It is important to know if nutritionally-induced oxidative stress that has altered viral virulence and pathogenesis will affect other intestinal pathogens, including parasites and microbial pathogens. This could have implications for the appearance of new and more virulent pathogens that are not exclusively viral. The results of this research will provide health-care professionals and the public with information needed to determine if specific nutrients can improve disease resistance and intestinal function, and if the recommendation for adequate nutrient intake will have broad affects on the control of intestinal infection. No actual or potential impact has yet been reached since the broad application of the observation has not been tested. Milestones 1 and 2 have been substantially met as the model is currently well defined and suitable for moving towards Milestones 2-4 over the next three years of the project.
6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
This proposal is related to a research grant entitled "GI Nematode and Gut Functional Responses to Inflammation" with a cooperating scientist at the University of Maryland, School of Medicine, Mucosal Biology Division, that was funded by the National Institutes of Health, TMP Section; period: April 2002 to March 2007.
7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).
Summers, R.W., Elliott, D.E., Urban, J.F. Jr., Thompson, R.A., Weinstock, J.V. 2005. Trichuris suis therapy for active ulcerative colitis: A randomized controlled trial. Gastroenterology. 128:825-832.
Auyeung, K., Smith, A.D., Zhao, A., Madden, K., Elfrey, J., Sullivan, C., Levander, O.A., Urban Jr, J.F., Shea Donohue, P.T. 2005. Impact of vitamin E or selenium deficiency on nematode-induced alerations in murine intestinal function. Experimental Parasitology. 109:201-208.
Summers, R., Elliott, D., Urban Jr, J.F., Thompson, R., Weinstock, J. 2005. Trichuris suis gut therapy in crohn's disease. Gut. 54:87-90.
Liu, Z., Liu, Q., Pesce, J., Anthony, R., Lamb, E., Whitmire, J., Hamed, H., Morimoto, M., Urban Jr, J.F., Gause, W.C. 2004. Requirements for the development of IL-4producing T cells during intestinal nematode infections: what it takes to make a Th2 cell in vivo. Immunological Reviews 201:57-74.
Finkelman, F., Shea-Donohue, T., Morris, S., Gildea, L., Strait, R., Madden, K., Urban Jr, J.F. 2004. IL-4 and IL-13 mediated host protection against intestinal nematode parasites. Immunological Reviews 201:139-155.
Zao, A., Morimoto, M., Dawson, H., Elfrey, J.E., Madden, K.B., Gause, W.C., Min, B., Finkelman, F.D., Urban, J.F. Jr., Shea-Donohue, T. 2005. Immune regulation of protease-activated receptor-1 expression in murine small intestine during nippostrongylus brasiliensis infection. Journal of Immunology. 175(4):2563-2569.