Intestinal mucosal secretion of basic fibroblast growth factor in patients with ulcerative colitis

Basic fibroblast growth factor (bFGF) promotes angiogenesis and several other biologic processes, including proliferation of mesenchymal cells and tumor progression. We investigated whether bFGF could be detected in the intraluminal secretion of the small intestine, sigmoid colon, and rectum in healthy individuals and in patients with ulcerative colitis.

We used endoscopic perfusion techniques to obtain samples from well-defined intestinal segments. The perfusion fluid concentrations of bFGF, biochemical markers of inflammation, myeloperoxidase (MPO), interleukin-6 (IL-6), and permeability (albumin) were determined with immunochemical methods.

In the perfusion fluids the albumin concentration, which reflects passive diffusion, was less than 1% of the plasma concentration, whereas the intestinal concentration of bFGF was similar to that in plasma. Among healthy subjects the concentration of bFGF was eightfold higher in the jejunum and twofold higher in the rectum than in the sigmoid colon. The perfusion fluid from colorectal segments in patients with ulcerative colitis had a significantly higher mean concentration of bFGF than that from healthy individuals; an almost 10-fold difference was found in rectal segments. There were strong correlations between the concentration of bFGF and the concentrations of MPO and IL-6.

The high concentrations of bFGF in the intestinal perfusion fluid reflect either a local synthesis or an active secretion of bFGF within the mucosa. The bFGF concentration differs in intestinal anatomic location and increases significantly in patients with ulcerative colitis in close relationship with biochemical markers of inflammation and permeability.