Gut inflammation and stool tests overview

The gut’s immune system is ultimately responsible for maintaining a healthy gut free of infection or infestation. It must accomplish this task while at the same time being unresponsive to food and helpful bacteria (1).

Gastrointestinal inflammation etiology is largely infection such as via parasite. However, modern lifestyles have increasingly been harassed by new chronic inflammatory diseases such as Crohn’s or ulcerative colitis (1). These are associated mainly with genetic mutations or adaptive immunity affecting immune system recognition as well as by epithelial permeability (1).

Stool tests indicating gastrointestinal inflammation include those for fecal proteins such as eosinophil protein-X (EPX), fecal calprotectin (FC) and fecal myeloperoxidase (MPO):

• FC is a calcium-binding protein found in large amounts in neutrophils and macrophages, which rush into the lumen at onset of inflammation (2-4). FC is considered more sensitive than endoscopy, for example, for evaluating inflammatory bowel disease such as ulcerative colitis and Crohn’s disease. Calprotectin can also be used to determine post-infectious irritable bowel syndrome, NSAID enteropathy or cancer.
  
• MPO is a derivative of neutrophil granulocytes (2). It’s useful diagnostically because it’s found in intestinal mucosa and in feces. Levels of MPO are elevated in active inflammatory bowel disease and mark mucosal inflammation. MPO and FC appear to be better markers in comparison to EPX during the treatment of inflammatory diseases ulcerative colitis or Crohn’s disease (2).
  
• EPX is a glycoprotein that is released when eosinophil granulocytes (white blood cells responsible for battling infectious parasites and bacteria) (2). Its increased levels in feces reflect infection, inflammation and tissue damage relating to food allergies, celiac disease, helminthic infection, inflammatory bowel disease, and cancer (5).

Reference List

1. MacDonald TT, Monteleone G. Immunity, inflammation, and allergy in the gut. Science 2005;307:1920-5.
2. Wagner M, Peterson CG, Ridefelt P, Sangfelt P, Carlson M. Fecal markers of inflammation used as surrogate markers for treatment outcome in relapsing inflammatory bowel disease. World J Gastroenterol 2008;14:5584-9.
3. Savino F, Castagno E, Calabrese R, Viola S, Oggero R, Miniero R. High Faecal Calprotectin Levels in Healthy, Exclusively Breast-Fed Infants. Neonatology 2009;97:299-304.
4. Gaya DR, Mackenzie JF. Faecal calprotectin: a bright future for assessing disease activity in Crohn's disease. QJM 2002;95:557-8.
5. Genova Diagnostics. 2009. "Comprehensive Digestive Stool Analysis 2.0" Gastrointestinal Assessments. Available at: http://blackboard.bridgeport.edu/@@651E45893EFF586CEA74E9CF68D701AA/courses/1/NUTR-560E-DLB-2009NF/content/_22116_1/Comprehensive%20Digestive%20Stool%20Analysis-%20Genova.pdf. Accessed 28 Nov 2009.