Splanchnic and renal extraction of circulating aminoterminal propeptide of type III procollagen and related antigens were studied in 12 patients with normal liver function and in 19 patients with alcoholic cirrhosis during catheterization.
Type III procollagen peptide in serum was measured in two assays: the Type III Procollagen Peptide Radioimmunoassay Kit, a new assay that selectively determines the intact propeptide (and larger type III propeptide-holding antigens) and the Type III procollagen Fab assay that measures both the intact propeptide and the smaller fragments that quantitatively dominate in serum.
A significant decrease in the concentration of the intact propeptide between the artery and the hepatic vein was found in the group with normal liver function (p < 0.01) and in patients with cirrhosis (p < 0.01). In patients with cirrhosis, however, the splanchnic extraction ratio of the intact propeptide (median = 0.04, range = -0.03 to 0.16) was significantly lower than in patients with normal liver function (median = 0.17, range = 0.05 to 0.36, p. < 0.01). The concentration of the intact propeptide in the hepatic vein was positively correlated to hepatic pressure (n = 18, r = 0.51, p < 0.05) and inversely correlated to indocyanine green clearance (n = 15, r = -0.61, p < 0.05). No splanchnic extraction could be demonstrated in the Type III propeptide Fab assay.
A significant renal extraction was found in the Fab assay, but not in Type III Procollagen Peptide Radioimmunoassay Kit. Similar extraction ratios were observed in both healthy patients (median = 0.11, range = 0.00 to 0.21) and cirrhotic patients (median = 0.14, range = 0.06 to 0.22).
Thus intact circulating type III procollagen peptide is extracted in the liver, and the extraction ratio is decreased in alcoholic cirrhosis. Smaller type III procollagen peptide-related antigens are extracted from the circulation by the kidneys.(HEPATOLOGY 1990;11:957-963.).