text: Collagen metabolites in the peripheral and splanchnic circulation of patients with Crohn disease.
  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. 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. 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). The present study provides further evidence that the altered intestinal collagen metabolism in Crohn disease is reflected in the local and systemic circulation.