Advances in the enzyme diagnosis of pancreatic diseases

Combination of high-density cholesterol level, elastic score, and severity of exocrine pancreatic dysfunction may be useful for a predictive factor for patients with early chronic pancreatitis

BACKGROUND

This study aimed to clarify whether any risk factors including clinical characteristics, endosonographic features, and exocrine pancreatic dysfunction may be useful for a predictive factor for patients with early chronic pancreatitis.

METHODS

A total of 163 consecutive patients that presented with functional dyspepsia with pancreatic enzyme abnormalities (FD-P) (n = 46), early chronic pancreatitis (ECP) (n = 47), and asymptomatic patients with pancreatic enzyme abnormalities (AP-P) (n = 70) based on the Rome III classification and the Japan Pancreatic Association were included in this study. The enrolled patients were evaluated using endosonography (EUS) and EUS elastography. The levels of the five pancreatic enzymes were measured. Pancreatic exocrine function was analyzed using N-benzoyl-l-tyrosyl-p-aminobenzoic acid (BT-PABA).

RESULTS

There were no significant differences in clinical characteristics such as age, gender, body mass index, alcohol consumption, and smoking among patients with AP-P, FD-P, and ECP. The ratio of BT-PABA test less than 35% in patients with ECP was significantly (P = 0.043) higher than in AP-P patients. Elastic score was a useful tool to differentiate the FD-P group from the ECP group. The high-density cholesterol levels in patients with ECP were significantly lower than those in AP-P. In addition, the combination of total and high-density cholesterol levels, BT-PABA test, and elastic score has a higher area under the curve value (0.708) of patients with ECP than in the other groups.

CONCLUSIONS

The combination of high-density cholesterol levels, elastic score, and severity of exocrine pancreatic dysfunction may be useful for a predictive factor for patients with ECP.

Pancreatic exocrine function and morphology following an episode of acute pancreatitis

OBJECTIVE

The objective of this study was to assess pancreatic exocrine function (PEF) and morphology in patients recovering from a first episode of acute pancreatitis (AP).

METHODS

Sixty-five eligible patients recovering from AP and 70 healthy volunteers were enrolled in this study. We evaluated PEF by fecal elastase 1 (FE-1) and used ultrasonography to detect pancreatic morphology for all patients and 40 controls.

RESULTS

Exocrine pancreatic insufficiency (EPI) incidence in the severe and mild AP subgroups was 60.5% and 39.5%, respectively. The FE-1 level in patients who had undergone surgical care was significantly lower compared with the controls (P < 0.01), whereas no difference was observed between the alcoholic and nonalcoholic groups (P > 0.05). Surprisingly, the defecation change correlated with the EPI level. In these patients, a stepwise recovery was observed over the following 2.4 years. Compared with the controls, the diameter of pancreatic duct was enlarged, and abdominal pain during recovery was found to be the independent risk factor for pancreatic duct expansion, although a significant difference was not exhibited between the AP subgroups concerning FE-1 concentration (P = 0.591).

CONCLUSIONS

Our results indicated that many AP patients may have long-lasting EPI and an expanded main pancreatic duct; thus, routine evaluation of PEF is warranted.

Amylase measurement with 2-chloro-4-nitrophenyl maltotrioside as substrate

The use of 2-chloro-4-nitrophenyl maltotrioside (CNP-G3) as substrate to measure amylase (EC 3.2.1.1) activity in serum directly without the use of auxiliary enzymes was evaluated at two centres. The method was precise (within-run C.V. < 2% and between-run C.V. < 3%), there was no lag phase, background absorbance was low and there were minimal effects of pH changes. When compared with a method which uses 4,6-ethylidene (G7)-p-nitrophenyl (G1)-alpha-D-maltoheptaoside (EPS-G7) as substrate, the CNP-G3 method had greater sensitivity and longer reagent stability (21 days compared with 2 days at 4 degrees C). The activity measured with the CNP-G3 method correlated well with methods using either EPS-G7 and maltotetraose as substrates.

Cystic fibrosis. Gastrointestinal complications and gene therapy

The gastrointestinal and nutritional complications of cystic fibrosis are diverse. As longevity improves in patients with cystic fibrosis, management of these complications is becoming increasingly important . This article provides overviews of the molecular aspects of the pathogenesis of cystic fibrosis, the current status of gene therapy, and a review of the gastrointestinal manifestations and nutritional care.

Serum levels of pancreatitis-associated protein as indicators of the course of acute pancreatitis. Multicentric Study Group on Acute Pancreatitis

BACKGROUND/AIMS

The pancreatitis-associated protein (PAP) is undetectable in normal pancreatic secretion and overexpressed in the acute phase of pancreatitis. We investigated whether serum PAP could be an indicator of the course of acute pancreatitis.

METHODS

Serum PAP was retrospectively monitored in 98 patients with acute pancreatitis during their stay in the hospital. Patients were classified according to the severity of their disease as group I (< or = 1 complication), group II (> or = 2 complications), or group III (lethal pancreatitis).

RESULTS

At admission, 34% of patients, all from group I, had normal PAP values (< 10 micrograms/L). None of them developed complications. They had a significantly shorter stay in the hospital than patients with elevated PAP (6.2 days vs. 14.9 days). In all patients, serum PAP increased after admission to a maximum, which correlated significantly to the severity of the disease. Average peak values were 22.2 micrograms/L and 240.0 micrograms/L in group I patients with normal or high PAP at admission, 963.0 micrograms/L and 1436.0 micrograms/L in groups II and III. Serum PAP decreased steadily during recovery.

CONCLUSIONS

Monitoring serum PAP in patients with acute pancreatitis would provide (1) at admission, selection of most patients who will not develop complications; (2) a dynamic assessment of severity; and (3) anticipation of the patient's recovery.

Biochemical tests in the diagnosis of chronic pancreatitis and in the evaluation of pancreatic insufficiency

Chronic pancreatitis (adults) and cystic fibrosis (children) are the most common diseases leading to exocrine pancreatic insufficiency that, when reduced to < 5% of normal function, is characterised by steatorrhoea. The pathogenesis of the former condition is outlined, and recent concepts are emphasized. Biochemical tests to detect pancreatic insufficiency and to identify pancreatic disease as the cause of steatorrhoea include: serum enzyme tests (lipase, amylase, trypsin); stool chymotrypsin; isotopic tests based upon the assimilation of [14C] lipids and starch or excretion of the isotope as breath CO2, as well as the dual-labelled Schilling test; oral function tests utilising substrates hydrolysed by pancreatic enzymes such as benzoyl tyrosyl-p-aminobenzoic acid and fluorescein dilaurate; and duodenal intubation studies following meal-induced or hormonal stimulation of the pancreas. The rationale for these tests and the cumulative clinical experience of their utility are reviewed. A recommended diagnostic strategy is briefly presented. The role of various biochemical procedures to evaluate the efficacy of pancreatic enzyme replacement therapy is also described.

Detection of human pancreatic pro-phospholipase A2 activation using an immunoassay for the free activation peptide DSGISPR

There are several forms of the enzyme phospholipase A2 (PLA2) in human tissues. In the pancreas the enzyme is produced as a zymogen, pro-phospholipase A2 (pro-PLA2). The active form is generated upon proteolytic cleavage of the N-terminal prophospholipase A2 activation peptide (PLAP), with the sequence Asp-Ser-Gly-Ile-Ser-Pro-Arg (DSGISPR). Antisera specific for free PLAP were produced by immunization with the synthetic peptide, N-terminally conjugated to bovine thyroglobin. Affinity purified antibodies were used to develop a radioimmunoassay with a detection limit of 5 nmol/L. Competitive inhibition studies with amino-terminally truncated sequences showed that, at least, the C-terminal pentapeptide (GISPR) was required for significant inhibition. Anti-PLAP antibodies did not react with native human pancreatic homogenate (a source of pro-PLA2). A large immunoreactive signal was generated upon trypsinization, which coeluted with synthetic PLAP when chromatographed on Sephadex-G25. Likewise, Sephadex-G50 chromatograph fractions of the untrypsinized homogenate reacted with the antibodies only after trypsinization. The immunoreactive signal appeared at a molecular weight of 14,500 which corresponds to the reported molecular weight of pancreatic pro-PLA2. This demonstrates that the assay is specific for the free peptide and reports pro-PLA2 activation. PLAP assay may therefore contribute to the study of the role of the PLA2 activation event in disease states such as pancreatitis.