Pancreatic stones of patients with chronic calcifying
pancreatitis (CCP) are mostly made up of CaCO3 crystals. Formation and growth of such crystals is inhibited in vitro by
lithostathine, a
protein present in normal pancreatic juice. Decreased
lithostathine activity was therefore suspected in patients with CCP, but comparison by immunoassay of
lithostathine concentrations in the pancreatic juices of patients and controls led to conflicting results. This study shows that these discrepancies might have been caused in part by a remarkably high susceptibility of the
protein to
trypsin like cleavage, resulting in important structural changes and concomitant modifications of the
epitopes. A novel
lithostathine assay in juice was developed, based on separation of secretory
proteins by high performance liquid chromatography. The chromatographic separation of
lithostathine was based on hydrophobic interactions at pH 5.0 using a Phenyl-TSK column. This study showed with this assay that
lithostathine concentrations (microgram/mg of total
protein) were similar in CCP patients with alcoholic aetiology (mean (SD) 6.3 (2.7)) and other aetiologies (7.2 (3.7)), but one third of those estimated in patients without
pancreatic disease (16.7 (4.3)). Similar concentrations were found, however, in chronic alcoholic patients without CCP (6.6 (3.3)) and in patients with CCP. It was concluded that decreased
lithostathine concentration is associated with CCP, although such a decrease is not sufficient by itself for the disease to occur.