The Clinical Utility of Fecal Calprotectin and Lactoferrin in Patients Undergoing Capsular Endoscopy: A Prospective Study

Capsule endoscopy (CE), a novel and wireless method of investigating the small bowel uses a remote instrument that is swallowed and propelled through the gastrointestinal tract by the action of peristalsis. The capsule contains an imaging device, which transmits images of the intestine to sensors on the abdominal wall. It has the ability to detect diffuse mucosal disease but without the inadvertent radiation exposure. Numerous studies have compared the utility of small bowel radiology to CE for the investigation of Crohn's disease. A recent meta-analysis showed that CE is superior to small bowel radiology, CT enterography and ileo-colonoscopy in the setting of suspected Crohn's disease. Capsule endoscopy has now developed an established role in the investigation pathway of small bowel Crohn's disease. However CE requires placement of an eight-lead sensor array over the abdomen that receives image and localization data transmitted from the capsule. The current process of applying this array to the skin has several disadvantages: firstly, it is time-consuming; secondly, it can be cumbersome for the patient; and thirdly, it is often difficult to place the leads consistently. Moreover, CE is expensive and results are largely influenced by the operator's skills.

Among the available fecal biomarkers for the diagnosis and monitoring of inflammatory bowel disease (IBD), only calprotectin and lactoferrin have translated into useful clinical tools.

Calprotectin (MRP8/14) is a calcium-binding heterodimer of the S100 protein family, presents in granulocytes, macrophages, and epithelial cells of humans and other mammals.It is believed to play an essential role in immunity. Calprotectin is released upon neutrophil/monocyte activation, when it can be detected in serum and body fluids, including stool. It is poorly degraded during passage through the gastrointestinal tract and remains stable in refrigerated storage. Together, these features make calprotectin a potentially useful marker of clinical inflammatory and neoplastic states. Recently, several studies suggested that a high fecal calprotectin concentration may distinguish patients with inflammatory bowel disease (IBD) from patients with irritable bowel syndrome (IBS).

Lactoferrin (LF) is an iron binding glycoprotein secreted by most mucosal membranes and a major component of secondary granules of polymorphonuclear neutrophils, a component of the inflammatory response. A number of studies have investigated the use of lactoferrin as a non invasive marker in the distinction of inflammatory bowel disease (IBD) and non inflammatory conditions. Whilst a high sensitivity of LF has been reported for active IBD in comparison to IBS, the distinction of inactive IBD and IBS is less clear . Lactoferrin can be detected using simple and cheap techniques and it has excellent stability in feces over a long period of time. Fecal lactoferrin has a good diagnostic precision for separating organic and functional intestinal disease.

The aim of this prospective study is to assess the clinical utility of fecal calprotectin and lctoferrin in patients undergoing CE.