Collagen Metabolites in the Peripheral and Splanchnic Circulation of Patients with Crohn Disease

BACKGROUND: Fragments of collagen arising during synthesis and breakdown have been suggested as markers of fibrous tissue remodelling in Crohn disease. We compared serum concentrations of the C-terminal propeptide of collagen I (PICP), the N-terminal propeptide of collagen III (PIIINP) and the C-terminal telopeptide of type I collagen (ICTP) in the splanchnic and systemic circulation in Crohn disease requiring segmental intestinal resection. METHOD: 15 consecutive patients undergoing surgery due to strictures or continuous inflammation. Male:female ratio was 6:9. Blood was drawn from a peripheral vein prior to surgery. Immediately before intestinal resection, additional samples were drawn from the antecubital vein and from a mesenteric vein draining the affected intestinal segment. PIIINP, PICP and ICTP were measured with radioimmunoassays. RESULTS: Pre-surgery S-ICTP (median 5.5 microg/L; range 3.2-17.2 microg/L) was significantly increased in peripheral blood compared with healthy controls (median 2.6 microg/L; range 0.6-5.7 microg/L), P < or = 0.05. By contrast, S-PICP (median 98 microg/L; range 62-137 microg/L) and S-PIIINP (median 2.5 microg/L; range 1.2-7.4 microg/L) were significantly lower than S-PICP (median 133 microg/L; range 66-284 microg/L) and S-PIIINP (median 3.4 microg/L; range 1.0-7.1 microg/L) in healthy controls, P < or = 0.05. During surgery. no difference in S-PICP and S-PIIINP was documented between peripheral blood and splanchnic blood. In contrast, S-ICTP was increased in splanchnic blood (median 6.2 microg/L; range 2.7-17.4) compared to peripheral blood (median 5.0 microg/L; range 3.1-13.4) (P=0.05). CONCLUSION: The present study provides further evidence that the altered intestinal collagen metabolism in Crohn disease is reflected in the local and systemic circulation.