Intestinal Fatty Acid Binding Protein: A Sensitive Marker in Abdominal Surgery and Abdominal Infection

Background: Intestinal fatty acid binding protein (iFABP) is elevated in plasma by intestinal injury. We investigated the influence of surgical trauma and severe sepsis caused by abdominal and pulmonary infection on plasma iFABP concentrations. Methods: Seventy-nine patients were included in this prospective observational study: 31 patients before elective major abdominal surgery (EMS), 33 patients with severe sepsis on admission to the intensive care unit (ICU), and 15 healthy volunteers who served as controls. Blood samples were taken before and after surgery for a period up to 5d. Results: Prior to surgery, EMS patients had increased iFABP concentrations in those patients with intestinal cancer compared with patients without intestinal cancer (217pg/mL, interquartile range [IQR] I-III 100-369pg/mL versus 79pg/mL, IQR I-III: 0-182pg/mL; p<0.01) and with controls (114pg/mL, IQR I-III: 103-124pg/mL; p<0.01). Surgical trauma increased iFABP levels in patients without intestinal cancer (240pg/mL, IQR I-III 111-305pg/mL; p<0.01). Within 24h after surgery, iFABP levels decreased to normal values. Patients with severe sepsis of abdominal origin had elevated concentrations compared with controls (324pg/mL [IQR I-III 0-649pg/mL]; p=0.05); in patients with pneumonia, iFABP levels were not significantly increased. Discrimination between intestinal- and pulmonary-induced sepsis was low (area under the curve [AUC] 0.693; 95% confidence interval 0.512-0.874). Conclusions: Surgical trauma and severe sepsis lead to elevated iFABP concentrations. However, intestinal malignant disease and in some patients severe sepsis caused by pneumonia also resulted in elevated iFABP concentrations. The results support the idea that epithelial injury of many causes leads to elevated concentrations of iFABP. The value of iFABP for differentiating pulmonary from intestinal sepsis is limited.