Impact of renal dysfunction on the diagnosis of acute pancreatitis using urinary trypsinogen-2: A retrospective study

AIM

Early diagnosis of acute pancreatitis is crucial, and urinary trypsinogen has been recently reported as a useful biomarker for diagnosing acute pancreatitis. We aimed to evaluate the impact of renal dysfunction on the diagnostic performance of urinary trypsinogen-2 for acute pancreatitis.

METHODS

We conducted a retrospective study using the clinical data of patients who visited the Department of Emergency and Critical Care at the University of Tokyo Hospital between 1 October, 2021, and 30 June, 2022. Patients with available data on qualitative urinary trypsinogen-2 levels were identified. We compared the urinary trypsinogen-2 levels among patients who were clinically diagnosed with acute pancreatitis. We further stratified the patients according to renal function parameters, such as serum creatinine level, blood urea nitrogen level, and estimated glomerular filtration rate, and evaluated the performance of urinary trypsinogen-2 as a biomarker for acute pancreatitis.

RESULTS

Within 9 months, 35 patients were identified. Of them, 22 patients showed positive results and 13 showed negative results on the urinary trypsinogen-2 test. The sensitivity, specificity, positive predictive value, and negative predictive value were 0.80, 0.40, 0.18, and 0.92, respectively. Based on the blood urea nitrogen level and estimated glomerular filtration rate, the prevalence of false-positive results was significantly higher in patients with reduced renal function than in those with normal renal function.

CONCLUSION

In patients with reduced renal function, the urinary trypsinogen-2 qualitative test results might be interpreted with caution when used for diagnosing acute pancreatitis.

A Paper-Based Near-Infrared Optical Biosensor for Quantitative Detection of Protease Activity Using Peptide-Encapsulated SWCNTs

A protease is an enzyme that catalyzes proteolysis of proteins into smaller polypeptides or single amino acids. As crucial elements in many biological processes, proteases have been shown to be informative biomarkers for several pathological conditions in humans, animals, and plants. Therefore, fast, reliable, and cost-effective protease biosensors suitable for point-of-care (POC) sensing may aid in diagnostics, treatment, and drug discovery for various diseases. This work presents an affordable and simple paper-based dipstick biosensor that utilizes peptide-encapsulated single-wall carbon nanotubes (SWCNTs) for protease detection. Upon enzymatic digestion of the peptide, a significant drop in the photoluminescence (PL) of the SWCNTs was detected. As the emitted PL is in the near-infrared region, the developed biosensor has a good signal to noise ratio in biological fluids. One of the diseases associated with abnormal protease activity is pancreatitis. In acute pancreatitis, trypsin concentration could reach up to 84 µg/mL in the urine. For proof of concept, we demonstrate the feasibility of the proposed biosensor for the detection of the abnormal levels of trypsin activity in urine samples.

Usefulness of urinary trypsinogen-2 and trypsinogen activation peptide in acute pancreatitis: A multicenter study in Japan

BACKGROUND

Rapid urinary trypsinogen-2 dipstick test and levels of urinary trypsinogen-2 and trypsinogen activation peptide (TAP) concentration have been reported as prognostic markers for the diagnosis of acute pancreatitis.

AIM

To reconfirm the validity of all these markers in the diagnosis of acute pancreatitis by undertaking a multi-center study in Japan.

METHODS

Patients with acute abdominal pain were recruited from 17 medical institutions in Japan from April 2009 to December 2012. Urinary and serum samples were collected twice, at enrollment and on the following day for measuring target markers. The diagnosis and severity assessment of acute pancreatitis were assessed based on prognostic factors and computed tomography (CT) Grade of the Japanese Ministry of Health, Labour, and Welfare criteria.

RESULTS

A total of 94 patients were enrolled during the study period. The trypsinogen-2 dipstick test was positive in 57 of 78 patients with acute pancreatitis (sensitivity, 73.1%) and in 6 of 16 patients with abdominal pain but without any evidence of acute pancreatitis (specificity, 62.5%). The area under the curve (AUC) score of urinary trypsinogen-2 according to prognostic factors was 0.704, which was highest in all parameter. The AUC scores of urinary trypsinogen-2 and TAP according to CT Grade were 0.701 and 0.692, respectively, which shows higher than other pancreatic enzymes. The levels of urinary trypsinogen-2 and TAP were significantly higher in patients with extended extra-pancreatic inflammation as evaluated by CT Grade.

CONCLUSION

We reconfirmed urinary trypsinogen-2 dipstick test is useful as a marker for the diagnosis of acute pancreatitis. Urinary trypsinogen-2 and TAP may be considered as useful markers to determine extra-pancreatic inflammation in acute pancreatitis.

A fluorometric sensing method for sensitive detection of trypsin and its inhibitor based on gold nanoclusters and gold nanoparticles

In this work, a facile, label-free, and sensitive fluorometric strategy for detection of trypsin and its inhibitor was established on the basis of the fluorescence resonance energy transfer (FRET) between mercaptoundecanoic acid functionalized gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) via protamine as a bridge. Protamine can trigger the aggregation of AuNPs and link AuNCs with aggregated AuNPs through electrostatic interaction. Compared with monodisperse AuNPs, the UV-vis absorption band of aggregated AuNPs overlapped considerably with the emission spectrum of AuNCs. Thus, the fluorescence of AuNCs was obviously quenched by the aggregated AuNPs through FRET. In the presence of trypsin, protamine was hydrolyzed into small fragments, leading to the deaggregation of AuNPs and breaking of the short distance between AuNPs and AuNCs, so the FRET process was inhibited, and the fluorescence of AuNCs was recovered. The increase in the fluorescence intensity of AuNCs was directly related to the amount of trypsin. Hence trypsin can be determined on the basis of the variation of fluorescence intensity, with a linear range of 5-5000 ng mL-1 and a detection limit of 1.9 ng mL-1. In addition, this system was used for the detection of trypsin inhibitor by application of the inhibitor isolated from soybean as a model. The sensing method was applied for trypsin detection in human urine and commercial multienzyme tablet samples with satisfactory results. Graphical abstract ᅟ.

Ultrasensitive detection of trypsin activity and inhibitor screening based on the electron transfer between phosphorescence copper nanocluster and cytochrome c

Trypsin, as one of important proteases, is specific for catalyzing the hydrolysis of peptide and ester bonds containing lysine and arginine residues at the C-terminus. The level of trypsin in biological fluids can serve as a reliable and specific diagnostic biomarker for pancreatic function and its pathological changes. Herein, we demonstrate the application of phosphorescent Cu NCs for trypsin detection for the first time depending on the electron transfer between Cu NCs and cyt c. Cyt c and Cu NCs were selected as the quencher and the fluorophore, respectively. Cu NCs could bind to the positively charged cyt c through electrostatic and hydrophobic interactions, and the phosphorescence of Cu NCs was efficiently quenched by the metal-containing heme of cyt c. In the presence of trypsin, cyt c was digested, thus phosphorescence of Cu NCs remained. Therefore, a new and continuous phosphorescence assay for the detection of trypsin activity and its inhibitor screening was established. The plot of relative fluorescence versus trypsin concentration obtains a good linear detection range from 0 to 20 ng/mL (R² = 0.9657), and a detection limit of 2 ng/mL, which is much lower than 20 ng/mL of the sensor in buffer solution because of urine amplifying the phosphorescence signal of Cu NCs based on the FRET strategy. This assay still has been successfully applied to trypsin inhibitor screening, demonstrating its potential application in drug discovery.

Simple and label-free liquid crystal-based sensor for detecting trypsin coupled to the interaction between cationic surfactant and BSA

Trypsin plays a central role in catalyzing the hydrolysis of peptide bonds, so a technique with simple operation is needed to monitor the activity of trypsin. Here a simple and label-free senor based on liquid crystals (LCs) was developed by employing bovine serum albumin (BSA) as the enzyme substrate and dodecyl trimethyl ammonium bromide (DTAB) as the controller for the alignment of LC. It was found that DTAB could form a self-assembled monolayer at the aqueous/LC interface to produce the dark optical images of LCs. And the addition of BSA could disturb the monolayer, so that the optical signal of LCs turned bright from dark. But the hydrolysis of BSA by trypsin resulted in the dark appearance. The sensing platform allows detection as low as 1 U/mL under the polarized light microscope based on at least three measurements. Moreover, this method was successfully applied in the detection of trypsin in human urines, suggesting its potential applications in clinic diagnosis.

Serum amylase and lipase and urinary trypsinogen and amylase for diagnosis of acute pancreatitis

BACKGROUND

The treatment of people with acute abdominal pain differs if they have acute pancreatitis. It is important to know the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis, so that an informed decision can be made as to whether the person with abdominal pain has acute pancreatitis. There is currently no Cochrane review of the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis.

OBJECTIVES

To compare the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase, either alone or in combination, in the diagnosis of acute pancreatitis in people with acute onset of a persistent, severe epigastric pain or diffuse abdominal pain.

SEARCH METHODS

We searched MEDLINE, Embase, Science Citation Index Expanded, National Institute for Health Research (NIHR HTA and DARE), and other databases until March 2017. We searched the references of the included studies to identify additional studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively. We also performed a 'related search' and 'citing reference' search in MEDLINE and Embase.

SELECTION CRITERIA

We included all studies that evaluated the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis. We excluded case-control studies because these studies are prone to bias. We accepted any of the following reference standards: biopsy, consensus conference definition, radiological features of acute pancreatitis, diagnosis of acute pancreatitis during laparotomy or autopsy, and organ failure. At least two review authors independently searched and screened the references located by the search to identify relevant studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included studies. The thresholds used for the diagnosis of acute pancreatitis varied in the trials, resulting in sparse data for each index test. Because of sparse data, we used -2 log likelihood values to determine which model to use for meta-analysis. We calculated and reported the sensitivity, specificity, post-test probability of a positive and negative index test along with 95% confidence interval (CI) for each cutoff, but have reported only the results of the recommended cutoff of three times normal for serum amylase and serum lipase, and the manufacturer-recommended cutoff of 50 mg/mL for urinary trypsinogen-2 in the abstract.

MAIN RESULTS

Ten studies including 5056 participants met the inclusion criteria for this review and assessed the diagnostic accuracy of the index tests in people presenting to the emergency department with acute abdominal pain. The risk of bias was unclear or high for all of the included studies. The study that contributed approximately two-thirds of the participants included in this review was excluded from the results of the analysis presented below due to major concerns about the participants included in the study. We have presented only the results where at least two studies were included in the analysis.Serum amylase, serum lipase, and urinary trypsinogen-2 at the standard threshold levels of more than three times normal for serum amylase and serum lipase, and a threshold of 50 ng/mL for urinary trypsinogen-2 appear to have similar sensitivities (0.72 (95% CI 0.59 to 0.82); 0.79 (95% CI 0.54 to 0.92); and 0.72 (95% CI 0.56 to 0.84), respectively) and specificities (0.93 (95% CI 0.66 to 0.99); 0.89 (95% CI 0.46 to 0.99); and 0.90 (95% CI 0.85 to 0.93), respectively). At the median prevalence of 22.6% of acute pancreatitis in the studies, out of 100 people with positive test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 74 (95% CI 33 to 94); 68 (95% CI 21 to 94); and 67 (95% CI 57 to 76) people have acute pancreatitis, respectively; out of 100 people with negative test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 8 (95% CI 5 to 12); 7 (95% CI 3 to 15); and 8 (95% CI 5 to 13) people have acute pancreatitis, respectively. We were not able to compare these tests formally because of sparse data.

AUTHORS' CONCLUSIONS

As about a quarter of people with acute pancreatitis fail to be diagnosed as having acute pancreatitis with the evaluated tests, one should have a low threshold to admit the patient and treat them for acute pancreatitis if the symptoms are suggestive of acute pancreatitis, even if these tests are normal. About 1 in 10 patients without acute pancreatitis may be wrongly diagnosed as having acute pancreatitis with these tests, therefore it is important to consider other conditions that require urgent surgical intervention, such as perforated viscus, even if these tests are abnormal.The diagnostic performance of these tests decreases even further with the progression of time, and one should have an even lower threshold to perform additional investigations if the symptoms are suggestive of acute pancreatitis.

A selective and sensitive fluorescent probe for the determination of HSA and trypsin

A simple fluorescent probe HBI-GR based on the combination of the fluorophore (p-HBI) in green fluorescent protein (GFP) and Guanine riboside (GR) for HSA was successfully synthesized. HBI-GR showed an obvious fluorescence enhancement toward HSA without interference from other proteins, amino acids, anions and commonly existing metal ions. HBI-GR exhibited high sensitivity towards HSA with a good linear relationship between the fluorescence intensity of HBI-GR and HSA concentration from 0 to 0.06mgmL^-1. The limit of detection, based on a signal-to-noise ratio of 3, was 15.09ngmL^-1, which was much lower than that of most other reported probes. HBI-GR was almost non-fluorescent because of the bond twisting in the exited state of chromophore HBI. After binding to the hydrophobic pocket of HSA, it showed an obvious fluorescence enhancement due to the rigidifying of the flexible chromophore HBI by the hydrophobic environment. The resulting HBI-GR/HSA system also showed a satisfactory sensing ability toward trypsin through decreased fluorescence intensity with the detection limit of 0.0282ngmL^-1. The fluorescence decreasing process was occurred as the lysine and arginine amino acids residues of HSA were cleaved by trypsin, which led to further exposure of HBI-GR to the PBS buffer phase and a concomitant decrease of the HBI-GR fluorescence intensity. Moreover, the probe HBI-GR was successfully used to detect HSA in healthy human urine and human blood serum samples. The practical application of the HBI-GR/HSA system for trypsin detection in healthy human urine also achieved satisfactory result.

[Clinical and laboratory diagnosis of an acute biliary pancreatitis]

In 126 patients, suffering an acute biliary pancreatitis (ABP), clinical examination was conducted. In 65 patients (1-st group) the isolated cholecystolithiasis was noted; in 35 (2-nd group)--cholelithiasis, which did not cause obturation of common biliary duct; in 26 (3-rd group)--cholelithiasis, which caused the biliary ways obturation (including calculi, which were incorporated into the duodenal papilla magna ostium). Clinical course of an ABP have differed depending on localization of calculi of extrahepatic biliary ducts. In patients, suffering ABP, a biochemical signs of hepatocytes functional disorders were observed, impacting the need for hepatoprotector preparations inclusion into complex of perioperative conservative therapy. Determination of activity of pancreatic α-amylase in the blood serum and conduction of the ACTIM Pancreatitis test con- stitute the most sensitive and specific methods of the ABP biochemical diagnosis.

Urinary trypsinogen-2 for diagnosing acute pancreatitis: a meta-analysis

BACKGROUND

Currently, serum amylase and lipase are the most popular laboratory markers for early diagnosis of acute pancreatitis with reasonable sensitivity and specificity. Urinary trypsinogen-2 (UT-2) has been increasingly used but its clinical value for the diagnosis of acute pancreatitis and post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis has not yet been systematically assessed.

DATA SOURCES

A comprehensive search was carried out using PubMed (MEDLINE), Embase, and Web of Science for clinical trials, which studied the usefulness of UT-2 as a diagnostic marker for acute pancreatitis. Sensitivity, specificity and the diagnostic odds ratios (DORs) with 95% confidence interval (CI) were calculated for each study and were compared with serum amylase and lipase. Summary receiver-operating curves were conducted and the area under the curve (AUC) was evaluated.

RESULTS

A total of 18 studies were included. The pooled sensitivity and specificity of UT-2 for the diagnosis of acute pancreatitis were 80% and 92%, respectively (AUC=0.96, DOR=65.63, 95% CI: 31.65-139.09). The diagnostic value of UT-2 was comparable to serum amylase but was weaker than serum lipase. The pooled sensitivity and specificity for the diagnosis of post-ERCP pancreatitis were 86% and 94%, respectively (AUC=0.92, DOR=77.68, 95% CI: 24.99-241.48).

CONCLUSIONS

UT-2 as a rapid test could be potentially used for the diagnosis of post-ERCP pancreatitis and to an extent, acute pancreatitis. Further studies are warranted to confirm these results.

Highly sensitive, label-free colorimetric assay of trypsin using silver nanoparticles

Herein, we report a simple, sensitive label-free colorimetric assay of trypsin based on silver nanoparticles (AgNPs) aggregation. Generally, a specially designed short peptide chain acts as both the stabilizer of AgNPs and the substrate of trypsin. In the presence of trypsin, the negatively charged part of peptides will be hydrolyzed, leaving the positively charged dipeptide capped on the surface of AgNPs. The electrostatic property alteration then leads to the AgNPs' aggregation in certain salt condition. The solution color may change correspondingly due to the localized surface plasmon resonance, which can be monitored by naked eye and UV-vis spectrophotometry. This novel AgNPs-based colorimetric method for quantitative determination of trypsin has a linear detection range from 2.5 to 200 ng mL(-1) and a rather low detection limit down to 2 ng mL(-1). The determination of trypsin can also be realized in complex biological fluids by the proposed method, demonstrating its great potential utility in the clinical applications in the future.

Point-of-care urine trypsinogen-2 test for diagnosis of acute pancreatitis

OBJECTIVES

To assess a point-of-care urine trypsinogen-2 (UT) test for the diagnosis of acute pancreatitis.

METHODS

This was a prospective study of patients presenting to the emergency department with abdominal pain suggestive of acute pancreatitis. A 3-minute point-of-care UT test (Actim Pancreatitis; Medix Biochemica, Kauniainen, Finland) was compared with final diagnosis of acute pancreatitis, which was based on suggestive clinical features, serum lipase and/or amylase levels and imaging.

RESULTS

Of 124 patients included in this study, 69 patients had final diagnosis of acute pancreatitis. The sensitivity and specificity of UT were, respectively, 73.9% (95% CI 61.9% to 83.8%) and 94.6% (95% CI 84.9% to 98.9%).

CONCLUSIONS

The point-of-care UT test for acute pancreatitis had good sensitivity and specificity, and can be used reliably at the bedside to make a positive diagnosis.

A comparative study of the urinary trypsinogen-2, trypsinogen activation peptide, and the computed tomography severity index as early predictors of the severity of acute pancreatitis

BACKGROUND/AIMS

The aim of the study was to establish the value of urinary trypsinogen-2 in predicting the severity of acute pancreatitis (AP) and to compare it with the accuracy of the urinary trypsinogen activation peptide (TAP) and the computed tomography severity index (CTSI).

METHODOLOGY

The study population consisted of 187 consecutive patients with AP, of whom 38 had severe disease. The predictive values of urinary trypsinogen-2, TAP and CTSI were assessed within 24 h of the onset of symptoms.

RESULTS

The mean values of predictive markers in the mild and severe pancreatitis groups were: urinary trypsinogen-2, 59/90 and 25/13 (p < 0.001); urinary TAP, 13.2 +/- 3.3nmol/l and 66.2 +/- 19.3 nmol/l (p < 0.001); and computed tomography severity index, 1.42 +/- 1.1 and 5.31 +/- 2.6 (p < 0.001). The sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios were calculated for the urinary trypsinogen-2 (65.7%, 66.4%, 33.3%, 88.4%, 1.9, and 0.51), for TAP (greater than 35 nmol/l: 63.2%, 65.8%, 32.0%, 87.5%, 1.9, and 0.58) and for CTSI (greater than 3: 47.4%, 95.3%, 69.2%, 87.7%, 9.0 and 0.55). To differentiate between severe and mild AP, urinary trypsinogen-2 (AUC 0.724) was slightly better than TAP (AUC 0.722), and they were both clearly better than CTSI (AUC 0.597) (p < 0.05). Urinary trypsinogen-2 had significantly lower cost (p < 0.001) than TAP and computed tomography.

CONCLUSION

Urinary trypsinogen-2 was superior to CTSI and was as good as or even better than urinary TAP in the early prediction of severity in AP. This suggests that this simple and quick method deserves routine clinical application.

The role of urine trypsinogen-2 test in the differential diagnosis of acute pancreatitis in the Emergency Department

BACKGROUND

The aim of the study was to investigate the role and importance of the urine trypsinogen-2 dipstick test in the differential diagnosis of acute pancreatitis in the Emergency Department and to compare results with those of conventional tests.

METHODS

The study was performed prospectively in the patients admitting to the Emergency Department due to upper abdominal pain. Thirty-two of the 87 patients included in the study had acute pancreatitis diagnosis. Serum amylase, lipase, C-reactive protein (CRP) and urine trypsinogen-2 using Actim pancreatitis dipstick were studied in all patients. The statistical analysis was performed using SPSS 11.5 package program.

RESULTS

Urine trypsinogen-2 was found positive in 21 (65.6%) of 32 patients. The sensitivity of the test for pancreatitis was identified as 64%, specificity as 85%, positive predictive value as 72%, and negative predictive value as 81%. These values were statistically significant compared to the control group (p<0.01).

CONCLUSION

Although it has lower sensitivity and specificity compared to amylase and lipase, we suggest that urine trypsinogen-2 test may be an important diagnostic tool in excluding the diagnosis of acute pancreatitis, since it provides results within 5 minutes in the Emergency Department, is cheaper, has a higher negative predictive value, and is easy to use.

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: frequency, time course and risk factors

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively.

Use of the urinary trypsinogen-2 dip stick test in early diagnosis of pancreatitis after endoscopic retrograde cholangiopancreatography

BACKGROUND

This study aimed to prove that the urinary trypsinogen-2 dip stick test can be used for early diagnosis of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

For this prospective, blinded, pilot study, urine samples were collected before ERCP, 1 h after ERCP, and 4 h after ERCP. The urine dipstick test was used to detect trypsinogen-2 on the basis of immunochromatography. The dipstick results were compared with those of current methods used to diagnose post-ERCP pancreatitis. Once the patient disposition was finalized, pancreatic enzymes, clinical findings, and final diagnosis were obtained from the chart and compared with the urine trypsinogen-2 test findings. The sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

The urine trypsinogen dip stick test was performed for 30 patients (15 men and 15 women). Post-ERCP pancreatitis was diagnosed in 5 of 29 patients by clinician assessment, serum pancreatic enzyme levels, or both. The amylase and lipase levels for post-ERCP patients with and without pancreatitis were 650 +/- 145 vs 134 +/- 26 (p = 0.023) and 1,658 +/- 594 vs 84 +/- 17 (p = 0.057), respectively. This statement proves that patients who developed post ERCP pancreatitis had significant elevation of amylase and lipase compared to patients who did not have pancreatitis. For the dip stick test, 6 of 28 patients had positive results in 1 h and 6 of 29 patients had positive results in 4 h. The sensitivity of the 1-h test was 1.0, and the specificity was 0.91. The positive predictive value (PPV) was 0.66, and the negative predictive value (NPV) was 1.0. The sensitivity of the 4-h test was 1.0, and the specificity was 0.96. The PPV was 0.8, and NPV value was 1.0.

CONCLUSION

The urinary trypsinogen-2 dip stick test is useful for early diagnosis of post-ERCP pancreatitis and allows the testing physicians to begin management early in its course.

Clinical value of rapid urine trypsinogen-2 test strip, urinary trypsinogen activation peptide, and serum and urinary activation peptide of carboxypeptidase B in acute pancreatitis

AIM

To assess the usefulness of urinary trypsinogen-2 test strip, urinary trypsinogen activation peptide (TAP), and serum and urine concentrations of the activation peptide of carboxypeptidase B (CAPAP) in the diagnosis of acute pancreatitis.

METHODS

Patients with acute abdominal pain and hospitalized within 24 h after the onset of symptoms were prospectively studied. Urinary trypsinogen-2 was considered positive when a clear blue line was observed (detection limit 50 microg/L). Urinary TAP was measured using a quantitative solid-phase ELISA, and serum and urinary CAPAP by a radioimmunoassay method.

RESULTS

Acute abdominal pain was due to acute pancreatitis in 50 patients and turned out to be extrapancreatic in origin in 22 patients. Patients with acute pancreatitis showed significantly higher median levels of serum and urinary CAPAP levels, as well as amylase and lipase than extrapancreatic controls. Median TAP levels were similar in both groups. The urinary trypsinogen-2 test strip was positive in 68% of patients with acute pancreatitis and 13.6% in extrapancreatic controls (P<0.01). Urinary CAPAP was the most reliable test for the diagnosis of acute pancreatitis (sensitivity 66.7%, specificity 95.5%, positive and negative predictive values 96.6% and 56.7%, respectively), with a 14.6 positive likelihood ratio for a cut-off value of 2.32 nmol/L.

CONCLUSION

In patients with acute abdominal pain, hospitalized within 24 h of symptom onset, CAPAP in serum and urine was a reliable diagnostic marker of acute pancreatitis. Urinary trypsinogen-2 test strip showed a clinical value similar to amylase and lipase. Urinary TAP was not a useful screening test for the diagnosis of acute pancreatitis.

Trypsin-2 degrades human type II collagen and is expressed and activated in mesenchymally transformed rheumatoid arthritis synovitis tissue

It has traditionally been believed that only the human collagenases (matrix metalloproteinase-1, -8, and -13) are capable of initiating the degradation of collagens. Here, we show that human trypsin-2 is also capable of cleaving the triple helix of human cartilage collagen type II. We purified human trypsin-2 and tumor-associated trypsin inhibitor by affinity chromatography whereas collagen type II was purified from cartilage extracts using pepsin digestion and salt precipitation. Degradation of type II collagen and gelatin by trypsin-2 was demonstrated with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, zymography, and mass spectrometry, and tumor-associated trypsin inhibitor specifically inhibited this degradation. Although human trypsin-2 efficiently digested type II collagen, bovine trypsin did not. Furthermore, immunohistochemical staining detected trypsin-2 in the fibroblast-like synovial lining and in stromal cells of human rheumatoid arthritis synovial membrane. These findings were confirmed by reverse transcriptase-polymerase chain reaction and nucleotide sequencing. Trypsin-2 alone and complexed with alpha(1)-proteinase inhibitor were also detected in the synovial fluid of affected joints by time-resolved immunofluorometric assay, suggesting that trypsin-2 is activated locally. These results are the first to assess the ability of human trypsin to cleave human type II collagen. Thus, trypsin-2 and its regulators should be further studied for use as markers of prognosis and disease activity in rheumatoid arthritis.

Rapid urinary trypsinogen-2 test strip in the diagnosis of acute pancreatitis

OBJECTIVES

Early diagnosis of acute pancreatitis remains a challenge. A rapid dipstick screening test for acute pancreatitis has been developed. This prospective study was designed to evaluate the diagnostic value and time course of the rapid urinary trypsinogen-2 test strip in acute pancreatitis, with comparisons with serum amylase and serum lipase.

METHODS

A total of 165 patients with acute abdominal pain (67 with acute pancreatitis and 98 with other acute abdominal diseases) attending our emergency unit were included. All patients were tested with the urinary trypsinogen-2 test strip, and serum amylase and serum lipase concentrations were determined simultaneously. To measure the time course of the urinary trypsinogen-2 test, 32 patients with acute pancreatitis were tested with a urinary trypsinogen-2 test strip on days 1, 2, 3, and 4 after admission.

RESULTS

Using a cutoff level of 50 microg/L for urinary trypsinogen-2, the sensitivity, specificity, and accuracy of the urinary trypsinogen-2 test strip for recognition of acute pancreatitis were 89.6%, 85.7%, and 87.3%, respectively. The diagnostic accuracy rates of serum amylase and serum lipase were 88.5% and 93.3%, using cutoff values of 3 times the upper normal limits for serum amylase and serum lipase, respectively. All but one of the 17 patients with severe acute pancreatitis was detected by the test strip (sensitivity, 94.1%). The time-course study of the urinary trypsinogen-2 test strip revealed that the sensitivity on days 1, 2, 3, and 4 was 90.6%, 81.2%, 59.4%, and 50%, respectively. There was no significant difference in the sensitivity between urinary trypsinogen-2 and serum lipase; however, the sensitivity values of serum lipase were significantly higher than those of serum amylase from days 1 to 4.

CONCLUSION

The rapid urinary trypsinogen-2 test is a reliable and simple method for the early diagnosis of acute pancreatitis. A positive test identifies patients in need of further diagnostic measures. The urinary trypsinogen-2 test can be performed in health care units where laboratory testing facilities are not immediately available.

[Recent advances in biochemical diagnosis and assessment of severity in acute pancreatitis]

Serum amylase is most commonly used as a biochemical marker of acute pancreatitis (AP). But it lacks specificity. The serum lipase level is more accurate and a better marker. Serum elastase -1 level is specific and remains elevated longer, but its radioimmunoassay is not routinely used. Recently, it can be rapidly measured by latex turbidometric immunoassay with automatic analyzer. Biochemically, only CRP test is available and useful to assess severity, but its sensitivity is unacceptably low in the early course of the disease. Urinary trypsinogen activation peptide (TAP) or trypsinogen-2 is an earlier marker. Increasing knowledge of the inflammatory process in AP has led to possibly useful biochemical indicators of severity, such as cytokines, nonpancreatic synovial type group II PLA2 or granulocyte elastase.

[Serine proteinase activity in children with hemolytic-uremic syndrome]

Haemolytic-uremic syndrome (HUS) is the leading cause of acute renal failure in the childhood. It is characterised by microangiopathic hemolytic anemia, thrombocytopenia, acute renal failure and injury of the renal microvascular endothelium. In HUS the condition of proteolytic kallikrein-kinin system is unknown. The renal KKS seems to participate in the regulation of blood pressure, control of sodium and water excretion, renal vascular resistance and renin release. In this study the role kallikrein in the developing HUS was studied. The general activity of kallikrein in plasma and urine was determined by trypsin-like peptidohydrolase activity (TP), which was measured using substrate Z-D-Ala-Leu-Arg-pNa. Chymotrypsin-like protease activity (ChP) was measured using substrate Glp-Ala-Ala-Leu-pNa. Clinical data were analysed on 60 pediatric patients with HUS, 29 girls and 31 boys, ranging in the age from 3 months to 11 years. TP and ChP levels were determined in different periods of HUS (anuria, diuresis beginning, polyuria, recovery) in serum and urine. In acute phase TP and ChP activities increased significantly. In diuresis recovery serum TP activity was higher, but urine TP level became normal. In dynamic serum and urine ChP levels had tendency to decrease. The present work showed that TP and ChP levels demonstrated activity of pathological renal process and condition of glomerules.

[Activity of endogenous proteinases in glomerulonephritis in children]

Protease activities in serum and urine of 116 children with glomerulonephritis and 16 healthy children were tested using chromogenic peptide substrates Z-Dala_Leu-Arg-pNA and Glp-Ala-ALa-Leu-pNa. We found the dependence between activity of serine proteinases and clinical, morphological forms of primary glomerulonephritis and hypertension.

Enzymatic digestion of the urethra after pancreatic transplantation: a case report

The most common method of exocrine drainage in pancreatic transplantation is urinary drainage. With the shift from enteric drainage and duct occlusion techniques, there has been a concomitant shift from intraabdominal to urological complications. We present a case in which a simultaneous pancreas-kidney (SPK) transplant recipient developed urethral disruption and associated bladder outlet obstruction 11 months following surgery.

Urinary trypsin levels observed in pancreas transplant patients with duodenocystostomies promote in vitro fibrinolysis and in vivo bacterial adherence to urothelial surfaces

This study evaluated the role of activated urinary trypsin in mediating the increased incidence of infectious and hemorrhagic lower urinary tract complications in pancreas transplant patients with pancreatico-duodenocystostomies (PDC). The effect of trypsin concentrations corresponding to those observed in the urine of PDC patients were studied using an in vitro assay of clot lysis and an in vivo assay of bacterial-urinary tract adherence. Results were compared with those of parallel assays performed using urine from a pancreas transplant patient with a duodenocystostomy and control human urine. All trypsin concentrations studied demonstrated fibrinolytic activity. Fibrinolysis increased as a direct function of both trypsin concentration and duration of substrate exposure (P < 0.0001). Fibrin lysis resulting from the urine of the transplant patient was 4.6 times greater than that predicted based upon assays of total trypsin content in the sample. Fibrinolytic activity in control urine specimens was 0.16% of that observed in transplant urine specimens. Exposure of the rat urinary bladder to 200 micrograms/ml trypsin concentrations, or transplant urine, resulted in a significant increase in bacterial adherence over that seen in control urine from treated animals (P < 0.05). These findings demonstrate a significant effect of urinary trypsin on physiologic processes involved in hemostasis and the prevention of urinary tract infection. Active urinary trypsin may play an etiologic role in hemorrhagic and infectious lower urinary tract complications observed in patients with a PDC.

Urinary enzymes excretion in pancreatic diseases. Clinical role and pathophysiological considerations

The amylase-creatinine clearance ratio was first proposed as a useful tool in the diagnosis of acute pancreatitis, and later it was claimed that trypsin creatinine clearance ratio was a sensitive and accurate test of pancreatic cancer. More recent observations have undermined the role of both clearances in the diagnosis of acute pancreatitis, and their utility in patients with chronic pancreatic diseases has largely been ignored. Three orders of factors, (a) the physicochemical characteristics of the protein, (b) the glomerular filtration rate variations, and (c) renal tubular damage, may have a role in determining the changes in the plasma-urine transfer of enzymes such as amylase and trypsin. Amylase urinary output is related both to variations in amylase serum levels (since this enzyme probably is not intensively reabsorbed by the tubule) and to the presence of renal tubular damage. Trypsin plasma-urine transfer changes depend greatly on the presence of tubular alterations. Elastase 1 and phospholipase A2 urinary outputs can also be predicted on the basis of the presence of tubular damage. Renal tubular alteration in pancreatic diseases may depend on the damaging effect of toxic substances (proteolytic enzymes, for example) released by the inflamed pancreas; the role of liver damage and of extrahepatic jaundice, which are frequent findings in chronic pancreatic diseases, should also be considered. However, toxic compounds such as ethanol, which can alter the pancreas and possibly the kidney, could also have a key role in the genesis of urinary findings in pancreatic diseases.

Characterization of immunoreactive trypsin as a means of differentiating graft pancreatitis and allograft rejection after porcine pancreatic transplantation

Graft pancreatitis and allograft rejection were both accompanied by increased serum levels of immunoreactive anionic trypsin (irAT) in a porcine pancreatic allograft transplantation model. Characterization of this immunoreactivity by gel filtration revealed different elution profiles in these conditions that can be helpful in the differentiation between them. During graft pancreatitis, a major part of the immunoreactivity was found within the high-molecular-weight fraction corresponding to the formation of complexes between trypsin and protease inhibitors. During allograft rejection, virtually all serum irAT increase could be attributed to the release of anionic trypsinogen without any evidence of activation. Since this transplantation model includes urinary diversion of the exocrine secretions, irAT and immunoreactive cationic trypsin (irCT) can also be measured in the urine. Characterization of this immunoreactivity showed that most of both irAT and irCT was found as active trypsin but a minor part was probably complexed with some protease inhibitor (possibly pancreatic secretory trypsin inhibitor [PSTI]).

Urinary levels of activated trypsin in whole-organ pancreas transplant patients with duodenocystostomies

Urinary levels of trypsinogen and active trypsin were measured in 34 urine samples from 14 patients an average of 23 months following whole organ pancreas transplantation and duodenocystostomy. Timed urine specimens obtained 30 min and 90 min following a time zero void were collected from 5 patients in an effort to define the kinetics of trypsinogen secretion and activation. Total urinary protein and urinary pH were correlated with urinary levels of trypsin and trypsinogen. Twenty-one specimens from 8 normal volunteers and a single specimen from a pancreas transplant patient with a duodenoenterostomy served as controls. Activated trypsin was present in 33 of 34 specimens from 13 of the 14 transplant patients. The average total trypsin activity in all samples was 84.4 micrograms/ml urine (+/- SE 9.6). Trypsinogen was present in 13 of 34 samples, from 7 of 14 patients. The average trypsinogen concentration of all 34 samples was 9.6 +/- 6.2 micrograms/ml. No trypsin or trypsinogen activity was identified in any control sample. In the 5 patients undergoing timed urine collections total trypsin increased an average of 1.3-fold at 30 min and 1.1-fold at 90 min relative to time zero. Urinary trypsinogen increased an average of 7.1-fold at 30 min and 3.1-fold at 90 min following the initial void. Urinary pH and total urinary protein failed to show a significant correlation with urinary levels of total trypsin or trypsinogen. These data suggest that trypsinogen is rapidly converted to active trypsin following secretion into the bladder, resulting in the high urinary trypsin levels that were detected in the majority of patients.

Early indicators of allograft rejection in a porcine pancreatic transplantation model

Urine cytology and blood lymphocyte blastogenesis were evaluated as indicators of allograft rejection in a porcine pancreatic transplantation model. The percentage of activated lymphocytes and/or blasts was significantly increased during the rejection phase. Positive cytology was present in all rejection episodes. An increased thymidine uptake of blood lymphocytes and a decreased uridine/thymidine uptake quotient were seen prior to the onset of rejection. The reported dissociation of anionic and cationic trypsin levels in serum and urine after transplantation was not seen after simple urinary diversion of the pancreatic juice. This supports the hypothesis that a decreased synthesis of cationic trypsinogen compared with anionic trypsinogen occurs after porcine pancreatic transplantation.

Pancreatic enzymes in serum and urine as indicators of pancreatic allograft rejection in the pig

We have studied the reliability of serum and urinary immunoreactive anionic trypsin (irAT), immunoreactive cationic trypsin (irCT), and amylase activity as rejection indicators in a porcine whole-organ pancreaticoduodenal transplantation model with exocrine drainage to the urinary bladder. No immunosuppressive therapy was administered. Exocrine tissue integrity and function were studied by measuring these enzymes in serum and urine. Urine analyses were performed before and after an intravenous secretin-cholecystokinin stimulation. Of 16 transplanted pigs, 10 became diabetic during a 2-week observation period while six remained normoglycemic. Serum irAT was found to predict rejection while serum amylase and serum irCT did not. An increase in irAT was seen in rejecting pigs preceding the onset of hyperglycemia by a median of 2 days (range 1-9). Secretion of irAT into the urine remained high during the observation period in nondiabetic pigs while the output declined in diabetic pigs. This decline was seen after the increase in serum irAT. When urine was sampled after a secretin-CCK stimulation, these findings were clearly evident, but less unequivocal results were obtained without stimulation. IrAT measurements were superior to measurements of amylase, irCT, or bicarbonate. Thus rejection of a pancreatic allograft was first indicated by a temporary rise in serum immunoreactive anionic trypsin, probably due to the onset of tissue damage. Thereafter, stimulated urinary enzyme output levels gradually declined and finally, hyperglycemia developed.

Renal handling of cathodic trypsin-like immunoreactivity in man

The renal handling of cathodic trypsin-like immunoreactivity (TLI) was examined in 60 healthy persons (group I), 59 patients with proteinuria (group II), 7 healthy men receiving intravenous lysine to partially inhibit renal tubular protein reabsorption (group III) and 20 patients who underwent diagnostic renal vein catheterization (group IV). The urinary TLI concentration and TLI ratio (TLI clearance divided with creatinine clearance) were higher in group II than group I (p less than 0.001, Mann-Whitney test). In group II negative correlations were present between serum TLI and creatinine clearance (Spearman's rho = -0.84, p less than 0.001) and between TLI ratio and creatinine clearance (rho = -0.76, p less than 0.001). In group III the renal TLI clearance was undetectable before lysine but increased to a maximal median value of 4.00 ml/min per 1.73 m2 (range: 2.44-9.25 ml/min per 1.73 m2) after lysine. In group IV, the renal arterio-venous extraction of TLI was correlated to inulin extraction (rho = 0.85, p less than 0.001). The glomerular filtrability (the ratio between TLI and inulin extractions) was median 0.53 (range: 0.13-0.94). In conclusion, TLI has a high glomerular filtration and an almost complete tubular reabsorption and catabolism (with normal kidney function).

Renal factors in serum trypsinogen 1 metabolism and excretion in chronic pancreatic disease

In order to investigate the role of renal factors in affecting trypsinogen 1 metabolism and excretion in chronic pancreatic disease, serum immunoreactive trypsin (IRT), urinary IRT, gamma-glutamyltransferase (GGT), alpha-glucosidase (AGL) and RNase outputs and the molecular size distribution of serum and urine IRT were studied in 8 control subjects, 18 cases with pancreatic cancer, and 23 cases with chronic pancreatitis. Serum chromatography demonstrated that most immunoreactivity eluted as trypsinogen 1. Smaller amounts of immunoreactivity at higher molecular weights were also observed. Urine chromatography displayed both trypsinogen 1 and heavier molecular forms. An inverse linear correlation was noticed between creatinine clearance and serum trypsinogen 1 levels. Multiple regression analysis (urinary IRT output dependent and GGT, AGL, and RNase predictor variables) showed a significant linear correlation. RNase was found to be the most important parameter in explaining urinary IRT output. Mild variations in the glomerular function seem to be able to influence serum trypsinogen 1 levels. Urinary IRT excretion is principally explained by a disturbance in the tubular reabsorption of low molecular weight proteins, such as RNase.

Molecular size distribution of immunoreactive trypsin and renal tubular dysfunction: role in trypsin plasma-urine transfer

In order to investigate the role of circulating free trypsinogen and renal tubular dysfunction in affecting trypsin plasma-urine transfer, serum immunoreactive trypsin (IRT), its urinary output, IRT molecular size distribution, filtrable immunoreactive trypsin, gamma-glutamyltransferase and alpha-glucosidase outputs were studied in 6 control subjects, 9 patients with pancreatic cancer and 15 with chronic pancreatitis. The majority of immunoreactivity was always eluted at a molecular weight of about 24,000 and might therefore be considered as free trypsinogen. Variable amounts of IRT at higher molecular weights, possibly represented by trypsin-inhibitor complexes, were also detected. Increasing IRT levels were generally accounted for by free trypsinogen, regardless of the nature of the disease. Unlike serum free trypsinogen levels, renal tubular damage, evaluated by means of the excretion of two high-molecular weight urinary enzymes, seems to play a prominent role in explaining trypsin plasma-urine transfer.

Pancreatic allograft exocrine urinary tract diversion. Pathophysiology

Exocrine secretions of 16 of 22 pancreas allografts were drained into the urinary tract. Seven of these 16 patients have functioning allografts, six with pancreaticocystostomies and one with duct-to-ureter anastomosis. A notable problem has been a chronic metabolic acidosis, along with weight loss and hypotension, secondary to chronic bicarbonate loss and volume depletion through the urinary pancreatic fistula. This occurred as early as one week posttransplant, and intermittently thereafter up to four years. The syndrome was aggravated by episodes of renal dysfunction (acute tubular necrosis or rejection), and febrile syndromes. An inverse relationship between serum and urine bicarbonate concentrations existed, with a correlation coefficient, r = -0.746, (P less than 0.05). A negative correlation was also noted between serum bicarbonate and serum creatinine, r = 0.726, (P less than 0.05). Hyperchloremic metabolic acidosis with normal anion gap occurred despite periods of marginal pancreas allograft function resulting from ongoing rejection. Treatment consisted of intravenous and/or oral bicarbonate supplementation, and bicarbonate dialysis for uremic patients. In addition, one patient was first seen with severe balanitis and urethritis due to documented activation of trypsinogen and chymotrypsinogen, presumably caused by recurrent episodes of urinary tract infection. Urinary assay revealed a 10(2-3) increase in activated trypsin and chymotrypsin in comparison with other asymptomatic allograft recipients. Conversion to ductal enteric drainage led to resolution of both the balanitis and bicarbonate wasting. Measurement of urinary amylase levels were gross indicators of graft viability since no correlation could be found between these levels, onset of hyperglycemia, and eventual graft rejection confirmed by pathological examination.

The use and mechanism of urinary clearance of cathodic trypsin-like immunoreactivity to creatinine clearance ratio in the diagnosis of pancreatic cancer

The ratio between urinary clearance of cathodic trypsin-like immunoreactivity and creatinine clearance (CTr/CCr ratio) was evaluated as a test for pancreatic cancer in patients with chronic pancreatic diseases and gastrointestinal diseases clinically mistakable for pancreatic cancer. The efficiency of the CTr/CCr ratio in the diagnosis of pancreatic cancer was no better than the urinary clearances of albumin and beta2-microglobulin to creatinine clearance (CA1b/CCr ratio and C beta 2m/CCr ratio). An overall positive association was found between the three ratios. Furthermore, there was a positive relationship between proteinuria and elevation of any of the ratios--as well as between proteinuria and the degree of cancer dissemination. The latter was positively associated with elevation of any of the three ratios. The results point to a changed renal handling of proteins due to cancer disease per se as the mechanism causing elevated CTr/CCr ratios in pancreatic cancer.

Purification and partial characterization of two forms of urinary trypsin inhibitor

Crude urinary trypsin inhibitor was obtained by DEAE-cellulose column chromatography from normal fresh urine. By the purification of the crude urinary inhibitor on successive chromatography methods using Sephacryl S-200, DEAE-cellulose, CM-Sepharose CL-6B and Sephadex G-100, we detected two forms of urinary trypsin inhibitor: form I and form II. The specific activity of form I increased approx. 4-fold with a recovery of 60%, as compared to that of crude urinary trypsin inhibitor. N-terminal amino acids of form I and form II were determined to be alanine and valine, respectively. Molecular weights of forms I and II were estimated to be 67000 and 28000 by gel filtration on Sephadex G-100 and to be 43000 and 19000 by SDS-polyacrylamide gel electrophoresis. S-carboxymethylated form I migrated as a single band corresponding to a molecular weight of 59000 in SDS-polyacrylamide gel electrophoresis. From the results of the determination of a single N-terminal amino acid of form I and a single band of S-carboxymethylated form I, it is indicated that it is composed of single polypeptide chain. And the present study suggests that form I is a native form of trypsin inhibitor in normal human urine and form II is a fragmented product from form I in the purification steps.

Urinary immunoreactive trypsin excretion: a non-invasive screening test for pancreatic cancer

The ratio of renal clearance of immunoreactive trypsin relative to renal clearance of creatinine was measured in 71 subjects including 27 controls and patients with cancer of pancreas, chronic pancreatitis, and acute pancreatitis. The upper limit of the control range was 4.1 x 10(-5) (mean + 2SD). 6 of 9 patients (67%) with acute pancreatitis had raised values. All 18 patients with chronic pancreatitis had values within the control range. In contrast, all 17 patients with carcinoma of pancreas had raised clearance ratios. The test may therefore prove valuable in distinguishing between chronic pancreatitis and cancer of pancreas.