Shinobu Hayakawa

Pancreatic stone protein and lactoferrin in human pancreatic juice in chronic pancreatitis.

Lactoferrin and pancreatic stone protein (PSP) are thought to be closely related to pancreatic stone formation in chronic pancreatitis. However, the results reported so far have not been conclusive. To reevaluate the pathological importance of PSP in chronic pancreatitis, compared to lactoferrin, levels of PSP were determined by applying an immunoassay specific to PSP to pure pancreatic juice taken from a total of 52 patients. The patients consisted of 16 controls, 19 chronic pancreatitis patients (13 noncalcified and 6 calcified), and 17 probable cases of pancreatitis. The monoclonal antibody PSP antagonist used in the study recognizes both forms of the protein, PSP S1 and S2–5, with equal effectiveness. No significant reduction of PSP was observed in either calcified (mean ± SEM, 111 ± 30 μg/mg and 24 ± 3 μg/mg protein) or noncalcified (305 ± 133 and 97 ± 47) chronic pancreatitis patients compared with controls (85 ± 23 and 34 ± 16). PSP levels did not decrease, at least not in the complete forms of the protein found in chronic pancreatitis. PSP antibody and assay results indicated that a reduction of PSP S2–5 alone could not be ruled out in chronic pancreatitis either.

Serum pancreatic stone protein in pancreatic diseases.

SummarySerum pancreatic stone protein (PSP) was determined in sera of pancreatic and nonpancreatic diseases using enzyme immunoassay specific to human PSP to study the diagnostic and pathophysiological significance of PSP. Serum PSP in acute pancreatitis (mean±SD=1075.4±2849.1 ng/mL,n=33) was significantly higher than that in controls (78.6±31.8 ng/mL,n=37,p<0.01), chronic pancreatitis (156.8±82.8 ng/mL,n=32,p<0.05), and pancreatic cancer (148.468.8 ng/mL,n=26,p<0.05). No significant difference was found between noncalcified and calcified chronic pancreatitis. Serum PSP levels were significantly higher in chronic renal failure under hemodialysis (1796.0±1492.9 ng/mL) than in other diseases such as peptic ulcer, liver cirrhosis, gallstone, and diabetes mellitus. Low but significant correlation was obtained between serum PSP and serum immunoreactive trypsin (r=0.22,p<0.05). Increased serum PSP levels in acute pancreatitis and chronic renal failure suggest that serum PSP levels reflect reflux from pancreatic secretion, release from damaged pancreatic acinar cells, or retention in circulation, and can be useful for diagnosis of acute pancreatitis, but not chronic calcified pancreatitis.

Trypsin(ogen) content of pancreatic calculi in chronic calcified pancreatitis in man

Protein analysis of intraductal precipitates and calculi is important to elucidate the mechanism of stone formation in chronic pancreatitis. We revealed human cationic trypsin immunoreactivity in protein extracts of pancreatic stones from 11 of 13 patients with chronic calcified pancreatitis, ranging from 0 to 42.3 ng/µg protein. On gel filtration the immunoreactivity eluted as one peak, which is identical to that of human cationic trypsinogen. On immunostaining of pancreatic stone, using an immunogold technic and scanning electron microscopy, the immunoreactivity was observed more densely in the amorphous portion of the center of the stones than in the concentric laminar layer of the periphery. Only negligible activity was detected for elastase 1 or amylase in the stone extracts. These results suggest that the presence of trypsinogen in pancreatic stone is not due to coprecipitation or adsorption of pancreatic enzymes but that trypsinogen is more likely involved in an initial step of intraductal precipitate formation than in a subsequent step of stone formation. However, the absence of trypsinogen in the stones from two of the 13 patients also suggests that trypsinogen is not the sole protein initiating precipitate formation.

Change of pancreatic enzymes, pancreatic stone protein (PSP), and plasma α2-macroglobulin-trypsin complex-like substance (MTLS) in the activation of pancreatic juice

To characterize the activation of pancreatic zymogens (trypsinogen, chymotrypsinogen, and proelastase 1) in acute pancreatitis, we studied the activation of pancreatic juice with porcine enteropeptidase in vitro, and then enzymatic activities and the generation of pancreatic stone protein (PSP) S1 form in pancreatic juice were investigated. Further, we determined immunoreactive trypsin, immunoreactive elastase 1, PSP, and α2-macroglobulin-trypsin complex-like substance (MTLS) levels in plasma to which the activated juice was added. In the present report, we demonstrate that the plasma MTLS level reflected the activation of pancreatic trypsinogen in pancreatic juice. Further, the generation of PSP S1 form was found at an early stage of activation. Therefore, the plasma MTLS level and the generation of PSP S1 form may offer new diagnostic information on the amounts of activated proteases and subsequently on the severity of acute pancreatitis.

Plasma α2-macroglobulin-trypsin complexlike substance (MTLS) in pancreatic disease

α2‐macroglobulin‐trypsin complexlike substance (MTLS) was determined in plasma of pancreatic and nonpancreatic diseases using a two‐step enzyme immunoassay to study the diagnostic and pathophysiological significance of MTLS. Plasma levels of MTLS in acute pancreatitis (mean ± SD = 265.6 ± 346.2 ng/ml, n = 9), calcified chronic pancreatitis (128.6 ± 257.4, n = 13), and noncalcified chronic pancreatitis (13.5 ± 12.5, n = 10) were significantly higher than that in controls (3.6 ± 1.8, n = 81). In other diseases such as gastric cancer, hepatoma, diabetes mellitus, and gallstones, MTLS values were not different from those of control. Plasma MTLS values showed low correlation with serum trypsin, elastase 1, pancreatic amylase, lipase, and pancreatic secretory trypsin inhibitor (PSTI). The elevation of plasma MTLS values in acute pancreatitis suggests that plasma MTLS levels reflect that protease is inappropriately activated in pancreatic acinar cell and released into the circulation and that the determination of MTLS can be useful for diagnosis and pathophysiology of acute pancreatitis and chronic pancreatitis.

Molecular forms of serum pancreatic stone protein in acute pancreatitis

SummaryConclusion: Elevation of serum pancreatic stone protein- (PSP) S1 suggests activation of trypsinogen in the pancreas. This information would prompt the start of intensive treatment and may improve prognosis of acute pancreatitis (AP).Background: PSP exists in two molecular forms, PSP-S2–5 and PSP-S1. PSP-S1 is produced by enzyme cleavage of PSP-S2–5 by trypsin. Total serum PSP rose in AP, but little is known about its molecular forms. In this study, we characterized the molecular forms of serum PSP in AP.Methods: Sera were taken from 8 patients with severe acute pancreatitis (sAP) and from 11 patients with mild acute pancreatitis (mAP). Serum PSP was characterized by high-performance liquid chromatography (HPLC) followed by the specific enzyme immunoassay (EIA).Results: The total serum PSP in sAP was higher than in mAP, but the difference was not significant. The PSP-S1 was detected in serum in all (7/7) patients in sAP and in 72% (8/11) of patients in mAP. Serum level of PSP-S1 was significantly higher in sAP than that in mAP (p<0.05), and the cutoff value to distinguish the two groups was 30 ng/mL. Serum PSP-S1 did not show significant correlation with total PSP, immunoreactive trypsin, or C-reactive protein.

Optimal conditions for collection of blood samples for assay of α2-macroglobulin trypsin complex-like substance (MTLS)

We have developed an enzyme‐linked immunosorbent assay (ELISA) for the specific quantification of α2‐macroglobulin‐trypsin complex‐like substance (MTLS). To exclude artifacts in measured values of MTLS, the conditions for collection of blood samples are critical. In the present study, we have determined the optimal conditions for blood collection and investigated the role of MTLS as a clinical tool for diagnosis in pancreatitis.