Serum complex of trypsin 2 and alpha 1 antitrypsin as diagnostic and prognostic marker of acute pancreatitis: clinical study in consecutive patients

Case Report: Exploration of changes in serum immunoinflammation-related protein complexes of patients with metastatic breast cancer

Patients with advanced breast cancer are difficult to treat and have poor prognosis. At present, the commonly used methods to monitor the disease progression of breast cancer are imaging examinations such as breast ultrasound, mammography and peripheral blood tumor markers such as carcinoembryonic antigen (CEA) and carbohydrate antigen 15-3 (CA15-3). However, none of them can detect tumor progression at an early stage. Serum immunoinflammation-related protein complexes (IIRPCs) showed potential to indicate cancer progression. Therefore, we attempted to monitor the level of IIRPCs in peripheral blood of patients with metastatic breast cancer and compare it with patients' treatment and disease progression, and here we performed case reports of two of them.

Serum α1-Proteinase Inhibitor, Calprotectin, and S100A12 Concentrations in the Characterization of Pancreatitis in Dogs

Miniature Schnauzers are predisposed to develop pancreatitis, with familial hypertriglyceridemia (HTG) described as a potential risk factor. Diagnosing pancreatitis in dogs is based on the integration of serum canine-specific pancreatic lipase (cPLI) concentration, clinical presentation, and diagnostic imaging findings. However, markers of systemic inflammation and antiprotease activity have not been extensively investigated in the characterization and prognostication of pancreatitis in dogs. Serum concentrations of alpha₁-proteinase inhibitor (α₁PI; as a marker of systemic antiprotease response) and calprotectin and S100A12 (as markers of systemic inflammation) were measured in serum samples from 35 Miniature Schnauzers diagnosed with pancreatitis (serum cPLI concentration >400 μg/L, clinical signs, abdominal imaging findings). These markers were evaluated for possible associations with patient characteristics, clinical presentation, risk factors for pancreatitis, and outcome. The study showed that biomarkers of systemic inflammation and antiprotease activity are commonly increased in Miniature Schnauzers with pancreatitis. Whereas serum calprotectin and S100A12 concentrations were found to have limited utility in differentiating pancreatitis presentations, serum α₁PI concentrations and potentially also the serum calprotectin-to-S100A12 ratio might be non-invasive surrogate markers of disease severity in dogs with pancreatitis.

Repeated Negative Urine Trypsinogen-2 Dipstick Test Rules Out Diagnosis of Post-ERCP Pancreatitis

BACKGROUND

A dipstick test for urine trypsinogen-2 has been used in the diagnosis of acute pancreatitis, but there are only a few studies exploring the effectiveness of this test for early diagnose of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP).

GOALS

The authors explore if the rapid point-of-care urine trypsinogen-2 dipstick test can replace assay of amylase in diagnosing PEP.

STUDY

For this prospective study, from Helsinki University Hospital 400 ERCP patients were enrolled in whom the authors analyzed plasma amylase or pancreas-specific amylase, bilirubin, and urine trypsinogen-2, and urine trypsinogen-2 with dipstick before, 4 and 24 hours after ERCP.

RESULTS

PEP developed in 15 (3.8%) patients. Urine trypsinogen-2 concentrations were significantly higher in PEP than in non-PEP patients 24 hours after ERCP (P=0.001, Mann-Whitney U test) but not 4 hours after ERCP (P=0.094). When combined with abdominal pain symptoms at 4 hours the dipstick test had a sensitivity of 60%, a specificity of 99%, a positive predictive value of 64%, and a negative predictive value 98%. At 24 hours, sensitivity was 100%, specificity 98%, positive predictive value 71%, and negative predictive value 100%.

CONCLUSIONS

A positive dipstick seems to identify PEP cases and a negative test excludes PEP with high accuracy.

Protease inhibitors, inflammatory markers, and their association with outcome in dogs with naturally occurring acute pancreatitis

Background

Acute pancreatitis (AP) presumably is associated with pancreatic protease activation, protease inhibitor (PI) depletion, and inflammatory mediator secretion.

Objectives

Examine PIs and inflammatory mediator concentrations in dogs with AP and their association with death.

Animals

Thirty‐one dogs diagnosed with AP based on clinical signs, ultrasonographic findings, and increased canine pancreatic lipase immunoreactivity (cPLI) and 51 healthy control dogs.

Methods

Antithrombin and α₂‐antiplasmin activity (ATA and α₂AP, respectively) and concentrations of α₁‐proteinase inhibitor (α₁PI), α₂‐macroglobulin (α₂MG), C‐reactive protein (CRP), interleukins (ILs)‐2,6,8 and tumor necrosis factor‐α (TNF‐α) were prospectively measured. Severity of AP was assessed by clinical severity scoring systems.

Results

Mortality rate was 19%. Antithrombin activity was lower (P = .004) and maximal CRP, IL‐6, and TNF‐α concentrations higher (P < .04) in the AP group compared to the controls, whereas IL‐2, IL‐8, α₁PI, and α₂AP concentrations did not differ between groups. Serum α₂MG concentration was not reliably detected. Serum cPLI, CRP, and IL‐6 concentrations were significantly and positively correlated. The ATA was lower (P = .04), and canine acute pancreatitis severity (CAPS) scores higher (P = .009) in nonsurvivors compared to survivors. Higher CAPS scores were associated (P < .05) with decreased ATA and increased cPLI, CRP, and IL‐6 concentrations.

Conclusions and Clinical Importance

Systemic inflammation in dogs with AP is manifested by increased inflammatory mediator concentrations, correlating with cPLI and CRP concentrations. Hypoantithrombinemia is associated with death. Serum concentrations of α₂AP and α₁PI are less useful prognostic markers. The CAPS score is a useful prognostic marker in dogs with AP.

Overview and prospect of serum markers for early prediction of severity of acute pancreatitis

Acute pancreatitis (AP) is one of the most common and potentially fatal emergencies of the digestive system. Aseptic inflammation of the pancreas caused by self-digestion of trypsin is considered to be the main pathogenesis of AP. The clinical course and prognosis of AP with different degrees of severity vary greatly, so early prediction of the severity of AP is of great significance to the diagnosis and treatment of this disease. In recent years, great progress has been made in the early risk assessment and severity stratification of AP patients with serum markers. This article gives an overview and discuss the prospects of serum markers for early prediction of the severity of AP.

Serum Serine Peptidase Inhibitor Kazal-Type 1, Trypsinogens 1 to 3, and Complex of Trypsin 2 and α1-Antitrypsin in the Diagnosis of Severe Acute Pancreatitis

OBJECTIVES

We explored prediction of severe acute pancreatitis (AP) and development of organ dysfunction (OD).

METHODS

Serum concentrations of serine peptidase inhibitor Kazal type 1 (SPINK1), trypsinogen 1, trypsinogen 2, and trypsinogen 3, complex between trypsin 2 and α1-antitrypsin, serum C-reactive protein, creatinine, and pancreatic amylase were measured in 239 AP patients with disease onset within 72 hours.

RESULTS

SPINK1 distinguished most accurately patients who later developed severe AP. The area under the receiver operating characteristic curve for SPINK1 was 0.742, followed by trypsinogen 2 (0.726), complex between trypsin 2 and α1-antitrypsin (0.657), creatinine (0.656), trypsinogen 1 (0.652), trypsinogen 3 (0.557), and C-reactive protein (0.499). With a cutoff of 166 μg/L, SPINK1 had a specificity of 93%, a sensitivity of 48%, and diagnostic odds ratio of 11.52. In multivariate logistic regression analysis, only SPINK1 was an independent predictor of severe AP among patients presenting without OD on admission (P < 0.001).

CONCLUSIONS

Plasma levels of the biomarkers and creatinine correlated with the severity of AP and development of OD. In patients presenting without OD at admission, SPINK1 was an independent marker for later development of severe AP.

Increased Levels of Serum Protein Complexes Are Associated with Type 2 Diabetes

Objective: To screen novel biomarkers in the levels of protein complexes for type 2 diabetes mellitus (T2DM). Methods: Serum immunoinflammation-related protein complexes (IIRPCs) and diabetes-related protein complexes (DRPCs) in 1537 serum samples including 504 healthy controls, 320 patients with prediabetes, and 713 patients with T2DM were analyzed using an optimized native polyacrylamide gel electrophoresis (native-PAGE). Results: Seven patterns of serum IIRPCs and four patterns of serum DRPCs were observed in the study population, respectively. Significant increase in the levels of serum IIRPCs in T2DM was detected relative to healthy controls. Change trends of serum DRPCs are as below: patients with T2DM>patients with prediabetes> healthy controls. Conclusion: Our findings suggest that increased levels of serum IIRPCs and DRPCs were associated with T2DM.

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.

Clinical Value of Severity Markers in Acute Pancreatitis

Acute pancreatitis is a common digestive disease of which the severity may vary from mild, edematous to severe, necrotizing disease. An improved outcome in the severe form of the disease is based on early identification of disease severity and subsequent focused management of these high-risk patients. However, the ability of clinicians to predict, upon presentation, which patient will have mild or severe acute pancreatitis is not accurate. Prospective systems using clinical criteria have been used to determine severity in patients with acute pancreatitis, such as the Ranson's prognostic signs, Glasgow score, and the acute physiology and chronic health evaluation II score (APACHE II). Their application in clinical practise has been limited by the time delay of at least 48 h to judge all parameters in the former two and by being cumbersome and time-consuming in the latter. Contrast-enhanced computed tomography is presently the most accurate non-invasive single method to evaluate the severity of acute pancreatitis. It cannot, however, be performed to all patients with acute pancreatitis. Therefore, considerable interest has grown in the development of reliable biochemical markers that reflect the severity of acute pancreatitis. In this article we critically appraise current and new severity markers of acute pancreatitis in their ability to distinguish between mild and severe disease and their clinical utility.

Biomarker development, from bench to bedside

This review describes studies performed by our group and other laboratories in the field aimed at development of biomarkers not only for cancer but also for other diseases. The markers covered include tumor-associated trypsin inhibitor (TATI), tumor-associated trypsin (TAT), human chorionic gonadotropin (hCG), prostate-specific antigen (PSA) and their various molecular forms, their biology and diagnostic use. The discovery of TATI was the result of a hypothesis-driven project aimed at finding new biomarkers for ovarian cancer among urinary peptides. TATI has since proved to be a useful prognostic marker for several cancers. Recently, it has been named Serine Peptidase Inhibitor Kazal Type 1 (SPINK1) after being rediscovered by several groups as a tumor-associated peptide by gene expression profiling and proteomic techniques and shown to promote tumor development by stimulating the EGF receptor. To explain why a trypsin inhibitor is strongly expressed in some cancers, research focused on the protease that it inhibited led to the finding of tumor-associated trypsin (TAT). Elevated serum concentrations of TAT-2 were found in some cancer types, but fairly high background levels of pancreatic trypsinogen-2 limited the use of TAT-2 for cancer diagnostics. However, trypsinogen-2 and its complex with α1-protease inhibitor proved to be very sensitive and specific markers for pancreatitis. Studies on hCG were initiated by the need to develop more rapid and sensitive pregnancy tests. These studies showed that serum from men and non-pregnant women contains measurable concentrations of hCG derived from the pituitary. Subsequent development of assays for the subunits of hCG showed that the β subunit of hCG (hCGβ) is expressed at low concentrations by most cancers and that it is a strong prognostic marker. These studies led to the formation of a working group for standardization of hCG determinations and the development of new reference reagents for several molecular forms of hCG. The preparation of intact hCG has been adopted as the fifth international standard by WHO. Availability of several well-defined forms of hCG made it possible to characterize the epitopes of nearly 100 monoclonal antibodies. This will facilitate design of immunoassays with pre-defined specificity. Finally, the discovery of different forms of immunoreactive PSA in serum from a prostate cancer patient led to identification of the complex between PSA and α1-antichymotrypsin, and the use of assays for free and total PSA in serum for improved diagnosis of prostate cancer. Epitope mapping of PSA antibodies and establishment of PSA standards has facilitated establishment well-standardized assays for the various forms of PSA.

Role of Biomarkers in Diagnosis and Prognostic Evaluation of Acute Pancreatitis

Acute pancreatitis is a potentially life threatening disease. The spectrum of severity of the illness ranges from mild self-limiting disease to a highly fatal severe necrotizing pancreatitis. Despite intensive research and improved patient care, overall mortality still remains high, reaching up to 30–40% in cases with infected pancreatic necrosis. Although little is known about the exact pathogenesis, it has been widely accepted that premature activation of digestive enzymes within the pancreatic acinar cell is the trigger that leads to autodigestion of pancreatic tissue which is followed by infiltration and activation of leukocytes. Extensive research has been done over the past few decades regarding their role in diagnosis and prognostic evaluation of severe acute pancreatitis. Although many standalone biochemical markers have been studied for early assessment of severity, C-reactive protein still remains the most frequently used along with Interleukin-6. In this review we have discussed briefly the pathogenesis and the role of different biochemical markers in the diagnosis and severity evaluation in acute pancreatitis.

Laboratory markers predicting severity of acute pancreatitis

Acute pancreatitis (AP) is an inflammatory disease of highly variable severity, ranging from mild cases with low mortality to severe cases with high mortality. Numerous biomarkers have been studied as potential early predictors of the severity of this disease so that treatment can be optimally tailored to prevent complications. We aim to present and discuss the most relevant biomarkers for early severity assessment in AP that have been studied to date. We review the current literature on biomarkers that have been used to predict the severity in AP. C-reactive protein (CRP) is still considered to be the gold standard, with a cut-off value of 150 mg/ml 48 h after disease onset. Other markers, including procalcitonin (PCT) and interleukin 6 (IL-6) have been implemented in some hospitals, but are not used on a routine basis. Most other markers, including acute phase proteins (LBP, SAA, PTX3), cytokines (Il-8, TNF-a, MIF), activation peptides of pancreatic proteases (TAP, CAPAP, PLAP), antiproteases (AAT, a2M), adhesion molecules (ICAM-1, selectins, E-cadherin) and leukocyte-derived enzymes (PA2, PMN-E) have shown some promising results but have not been routinely implemented. Furthermore, new and interesting biomarkers (Copeptin, TRX-1, Ang-2, E-2) have shown good results, but more research is needed to determine if they could play a role in the future. Various reasons why new markers for disease severity have not been adopted in daily routine include low accuracy, cumbersome laboratory techniques and high cost. Despite these difficulties, research is still very active in finding new markers to predict the severity of AP.

Elevation of urine trypsinogen 2 is an independent risk factor for pancreatic fistula after pancreaticoduodenectomy

OBJECTIVES

Previous reports suggested that the urine trypsinogen 2 (U-TRP2) test might be a valuable method for the diagnosis of postoperative pancreatitis after pancreatic surgery. We hypothesize that the elevation of U-TRP2 level after pancreaticoduodenectomy (PD) could be associated with the occurrence of postoperative pancreatic fistula (POPF).

METHODS

A total of 130 consecutive patients undergoing PD with duct-to-mucosa pancreaticogastrostomy were included. Urine samples for evaluation of U-TRP2 levels were collected prospectively. Risk factors for POPF were evaluated using univariate and multivariate analyses.

RESULTS

Of 130 patients, 19 developed POPF; grade A in 14 (11%), grade B in 3 (2%), and grade C in 1 (1%). Univariate analysis demonstrated that a nonobstructed main pancreatic duct, a pancreatic duct less than 3 mm, soft texture of the pancreatic gland, a PD with antrectomy, PD with hepatic resection, hyperamylasemia, and elevation of U-TRP2 levels (>50 μg/L) were significantly associated with POPF (P < 0.05). By multivariate analysis, elevation of U-TRP2 levels (odds ratio = 4.544, P = 0.029) was the only independent risk factor that correlated with POPF.

CONCLUSIONS

Elevation of U-TRP2 level is an independent risk factor for POPF after PD. Elevated U-TRP2 level might be the consequence of the postoperative pancreatitis, and postoperative pancreatitis may play an important role in the pathogenic mechanism of POPF after PD.

Monitoring Stepwise Proteolytic Degradation of Peptides by Supramolecular Domino Tandem Assays and Mass Spectrometry for Trypsin and Leucine Aminopeptidase

A label-free optical detection method has been designed that allows direct monitoring of enzymatic peptide digestion in vitro. The method is based on the addition of a reporter pair, composed of the macrocyclic host cucurbit[7]uril (CB7) and the fluorescent dye acridine orange (AO), to detect the proteolytic degradation of peptides. The enzymatic activity of trypsin and leucine aminopeptidase (LAP) was investigated using H-LSRFSWGA-OH as a substrate. The substrate as well as the intermediary and final products (i.e., H-FSWGA-OH and phenylalanine) formed during its enzymatic hydrolysis differ in their binding affinity to the receptor CB7, which results in varying degrees of dye displacement and, therefore, different fluorescence intensities. CB7 showed a relatively weak binding constant of K ≈ 104 M–1 with the substrate, a relatively strong binding constant of K ≥ 106 M–1 with H-FSWGA-OH (which is a final product formed by trypsin digestion and the intermediary product formed during the enzymatic activity of LAP), and a moderate binding constant of K ≤ 105 M–1 with phenylalanine. Owing to this differential binding affinity of CB7 with the substrate and the corresponding products, the digestion of a peptide by trypsin was followed as a decrease in fluorescence signal, while the complete degradation of the peptide by LAP was monitored as a decrease and a subsequent increase in fluorescence signal. The kcat/ KM value for trypsin (2.0 × 107 min–1M–1) was derived from the change in fluorescence signal with time. Additionally, the complete degradation of the peptide by LAP was also followed by mass spectrometry. The use of a supramolecular sensing ensemble (macrocyclic host and dye) as a fluorescent reporter pair gives this method the flexibility to adapt for monitoring the stepwise degradation of different biologically relevant peptides by other proteases.

Human trypsinogens in the pancreas and in cancer

This study led to the development of monoclonal antibodies and time-resolved immunofluorometric methods recognizing human trypsinogen-1 and -2, respectively. Using these methods in normal sera the concentration of trypsinogen-1 was found to be higher than that of trypsinogen-2. However, in acute pancreatitis the concentration of serum trypsinogen-2 was 50-fold higher than in controls, whereas the difference in trypsinogen-1 concentration was only 15-fold. Serum samples from patients who had undergone pancreatoduodenectomy contained trypsinogen-2, while trypsinogen-1 was detected in only one of nine samples. Furthermore, in human ovarian cyst fluids tumor-associated trypsinogen-2 (TAT-2) is the predominant isoenzyme and in mucinous cyst fluids the levels of TAT-2 were associated with malignancy. These results suggest that (i) trypsinogen-2 could be used as a diagnostic marker for acute pancreatitis, (ii) its expression is not restricted to the pancreas, and (iii) TAT could be involved in ovarian tumor dissemination and breakage of tissue barriers. In ion exchange chromatography, isoelectric variants of the trypsinogen isoenzymes were seen. Mass spectrometric analysis of these revealed that pancreatic trypsinogens are sulfated at tyrosine 154 (Tyr154), whereas TAT-2 from a colon carcinoma cell line is not. Tyr154 is located within the primary substrate binding pocket of trypsin. Thus, Tyr154 sulfation is likely to influence substrate binding. The previously known differences in charge and substrate binding between pancreatic and tumor-associated trypsinogens are suggested to be caused by sulfation of Tyr154 in pancreatic trypsinogens.

Risk assessment in acute pancreatitis

BACKGROUND

Acute pancreatitis has a variable natural history and in a proportion of patients is associated with severe complications and a significant risk of death. The various tools available for risk assessment in acute pancreatitis are reviewed.

METHODS

Relevant medical literature from PubMed, Ovid, Embase, Web of Science and The Cochrane Library websites to May 2008 was reviewed.

RESULTS AND CONCLUSION

Over the past 30 years several scoring systems have been developed to predict the severity of acute pancreatitis in the first 48-72 h. Biochemical and immunological markers, imaging modalities and novel predictive models may help identify patients at high risk of complications or death. Recently, there has been a recognition of the importance of the systemic inflammatory response syndrome and organ dysfunction.

Randomized clinical trial to assess the efficacy of ulinastatin for postoperative pancreatitis following pancreaticoduodenectomy

BACKGROUND AND OBJECTIVES

Ulinastatin, an intrinsic trypsin inhibitor, has proved to be effective for the prevention of acute pancreatitis after endoscopic retrograde cholangiopancreatography. The aim of this study was to assess the efficacy of ulinastatin for postoperative pancreatitis following pancreaticoduodenectomy in a randomized clinical trial.

METHODS

Patients undergoing pancreaticoduodenectomy were randomized to receive perioperative ulinastatin or placebo. Levels of serum amylase, drain amylase, and urine trypsinogen-2 were measured.

RESULTS

A total of 42 patients were enrolled (20 in the ulinastatin group, 20 in the placebo group, 2 excluded). Two patients in the ulinastatin group and nine patients in the placebo group developed hyperamylasemia (P = 0.013) No patient in the ulinastatin group and five patients in the placebo group developed pancreatitis (P = 0.016). One patient in the ulinastatin group and two patients in the placebo group developed grade A pancreatic fistula (P = 0.548). Serum amylase levels at 4 hr and postoperative days 1, 2, and 3, and drain amylase levels on days 2 and 3 were significantly lower in the ulinastatin group than in the placebo group.

CONCLUSIONS

Prophylactic administration of ulinastatin reduced the levels of serum and drain amylase and the incidence of postoperative pancreatitis following pancreaticoduodenectomy.

Risk and markers of severe acute pancreatitis

Acute pancreatitis begins with pancreatic injury, elicits an acute inflammatory response, and encompasses a variety of potential complications in a subset of patients. Early determination of severity and risk of complications is crucial for instituting immediate interventions to improve outcome. The severity of acute pancreatitis is a function of the amount of pancreas that is injured and the intensity of the inflammatory response. Early death is mainly linked to an overwhelming inflammatory response leading to cardiovascular collapse or acute respiratory distress syndrome, whereas late death is associated with infected pancreatic necrosis and sepsis. This article reviews recent advancements in understanding the pathogenesis, immunology, and genetics of severe acute pancreatitis, and the literature on laboratory-based markers, which predict a severe clinical course and pancreatic necrosis.

Serum macrophage migration inhibitory factor is an early marker of pancreatic necrosis in acute pancreatitis

OBJECTIVE

To determine if 24-hour blood concentrations of macrophage migration inhibitory factor (MIF), soluble CD14, and CD163 receptors could predict complications associated with acute pancreatitis (AP).

SUMMARY BACKGROUND DATA

Soluble receptor proteins derived from the macrophage-monocyte lineage potentiate the inflammatory cytokine response early in AP. Understanding the temporal expression of these molecules could afford better measures for therapeutic intervention.

METHODS

Patients with AP (amylase >5 times normal) were recruited within 24-hour of onset of pain. Peripheral blood was analyzed for MIF, sCD163, and sCD14 levels and levels correlated with CRP, APACHE-II score, and clinical disease severity (Atlanta criteria); subclassified as multiorgan dysfunction (MOF), pancreatic necrosis (PN >30% on contrast CT), and death.

RESULTS

In total, 64 patients with AP (severe, 19: 8 had MOF alone, 7 both PN and MOF, 2 PN without MOF, and 2 single-organ failures with local septic complications) were recruited. Both sCD14 and MIF concentrations were elevated in patients with severe attacks (P = 0.004 and P < 0.001 respectively), and patients who developed MOF (P = 0.004 and P < 0.001). However, only serum MIF was significantly raised in patients who subsequently developed PN (median, 92.5 ng/mL; IQR, 26-181 vs. 31.1 ng/mL; IQR, 5-82, P < 0.001), independently of MOF (P = 0.01). Multivariate analysis demonstrated serum MIF as an independent predictor of PN (P = 0.01; OR = 2.73; 95% CI, 2.72-2.74).

CONCLUSION

The prognostic utility of 24-hour plasma MIF concentration in predicting PN has major clinical and healthcare resource implications. Its mechanistic pathway may afford novel therapeutic interventions in clinical disease by using blocking agents to ameliorate the systemic manifestations of AP.

Biochemistry and clinical role of trypsinogens and pancreatic secretory trypsin inhibitor

Trypsinogens and PSTI/TATI/SPINK1 are expressed, usually together, at high levels by the pancreas but also by many other normal and malignant tissues. The present review describes studies on the expression and putative functions of trypsinogens and PSTI/TATI/SPINK1 in the human body. The clinical aspects are discussed, including the correlations between expression of trypsinogens and PSTI/TATI/SPINK1 in tissues, serum, and urine of patients with pancreatitis or cancer and clinicopathological characteristics, i.e., the roles of trypsinogens and PSTI/TATI/SPINK1 in spontaneous and hereditary pancreatitis, tumor progression, and prognosis.

Metabolic basis of ethanol-induced hepatic and pancreatic injury in hepatic alcohol dehydrogenase deficient deer mice

Alcoholic liver disease (ALD) and alcoholic pancreatitis (AP) are major diseases causing high mortality and morbidity among chronic alcohol abusers. Neutral lipid accumulation (steatosis) is an early stage of ALD or AP and progresses to inflammation and other advanced stages of diseases in a subset of chronic alcohol abusers. However, the mechanisms of alcoholic steatosis leading to ALD and AP are not well understood. Chronic alcohol abuse impairs hepatic alcohol dehydrogenase (ADH, a major enzyme involved in ethanol oxidative metabolism) and facilitates nonoxidative metabolism of ethanol to fatty acid ethyl esters (FAEEs, nonoxidative metabolites of ethanol). These esters are implicated in the pathogenesis of various alcoholic diseases and shown to cause hepatocellular and pancreatitis-like injury. Ethanol exposure is known to increase synthesis of FAEEs by several-fold in the livers and pancreata of rats pretreated with hepatic ADH inhibitor. Therefore, studies were undertaken to evaluate hepatocellular and pancreatic injury in hepatic ADH-deficient (ADH(-)) deer mice versus ADH-normal (ADH(+)) deer mice fed ethanol (4% wt/vol) via Lieber-DeCarli liquid diet for 60 days. A significant mortality was found in ethanol-fed ADH(-) deer mice (11 out of 18) versus ADH(+) deer mice (1 out of 16); most of the deaths occurred during the first 2 weeks of ethanol exposure. The surviving animals, sacrificed at the end of 60th day, showed distinct changes in hepatic and pancreatic histology and several-fold increases in nonoxidative metabolism of ethanol in ethanol-fed ADH(-) versus ADH(+) deer mice. Extensive vacuolization with displacement or absence of nucleus in some hepatocytes, and significant increase in hepatic neutral lipids were found in ethanol-fed ADH(-) versus ADH(+) deer mice. Ultrastructural changes showed perinuclear space, edema, presence of apoptotic bodies and disintegration, and/or dilatation of endoplasmic reticulum (ER) in the pancreata of ethanol-fed ADH(-) deer mice. FAEE levels were significantly higher in ADH(-) versus ADH(+) deer mice, approximately four-fold increases in the livers and seven-fold increases in the pancreata. Ethyl esters of oleic, linoleic, and arachidonic acids were the major FAEEs detected in ethanol-fed groups. The role of FAEEs in pancreatic lysosomal fragility is reflected by higher activity of cathepsin B (five-fold) in ethanol-fed ADH(-) versus ADH(+) deer mice. Although the present studies clearly indicate a metabolic basis of ethanol-induced hepatic and pancreatic injury, detailed dose- and time-dependent toxicity studies in this ADH(-) deer mouse model could reveal further a better understanding of mechanism(s) of ethanol-induced hepatic and pancreatic injuries.

Compartmentalization of the protease-antiprotease balance in early severe acute pancreatitis

OBJECTIVE

To assess the balance between trypsin and protease inhibitors simultaneously in the systemic circulation and in the thoracic lymph and peritoneal exudate.

METHODS

Twenty patients with early severe acute pancreatitis were studied. Enzymatically active and immunoreactive trypsin in conjunction with its major inhibitors were measured in the 3 compartments at the onset of end-organ failure(s). The molecular forms of trypsin were determined in the lymph and ascites by gel filtration chromatography to separate trypsinogen and free-and inhibitor-bound trypsin.

RESULTS

Both enzymatically active trypsin and immunoreactive trypsin levels were highest in ascites and lymph compared with the systemic circulation. Intracompartmental alpha1- protease inhibitor gradient moved in the opposite direction, whereas alpha2 macroglobulin concentration was highest in ascites and lowest in the lymph. Although most of the enzymatically and immunoreactive material in ascites and lymph consisted of trypsin complexed with alpha2 macroglobulin and trypsinogen, respectively, free active trypsin was detected in more than 80% of the samples.

CONCLUSIONS

In patients with early severe acute pancreatitis, there is a significant trypsinogen activation resulting in protease-antiprotease imbalance and thereby free enzymatically active trypsin in the 2 body fluid compartments in close vicinity to the inflammatory process. This may be involved in the pathophysiology of local and distant tissue damage.

Clinical laboratory assessment of acute pancreatitis

BACKGROUND

Several biochemical markers in blood and urine have been investigated to establish their clinical application in patients with acute pancreatitis (AP). The relevant studies are reviewed and critically appraised.

METHODS

Medline and the World Wide Web were searched and the relevant literature was classified under the following categories: (1) diagnosis of AP and (2) prediction of: a) disease severity, b) pancreatic necrosis and its secondary infection, c) organ failure and death, and d) disease etiology.

RESULTS AND CONCLUSIONS

Serum lipase is a more reliable diagnostic marker of AP than serum amylase. Urinary strip tests for trypsinogen activation peptide (TAP) and trypsinogen-2 provide a reliable early diagnosis of AP. Useful predictors of severity may include serum procalcitonin and urinary TAP and trypsinogen-2 on admission, serum interleukins-6 and -8 and polymorphonuclear elastase at 24 h, and serum C-reactive protein (CRP) at 48 h. Other markers such as amyloid A and carboxypeptidase B activation peptide (CAPAP) need further investigation. Biochemical prediction of pancreatic necrosis requires 72 h to reach reliability and is impractical. However, the daily monitoring of serum procalcitonin provides a non-invasive detection of infected necrosis; the promising role of phospholipase A(2) in this regard requires further investigation. Early transient hypertransaminasemia reliably predicts biliary etiology, while serum carbohydrate-deficient transferrin and trypsin may predict an alcoholic etiology.

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.

Inflammatory Markers of Disease Severity in Acute Pancreatitis

To date, CRP remains the single standard biochemical marker for predicting the severity of AP. Because the combination of clinico-physiological scores and CRP provides good information at 48 hours, research has focused on the predictive ability of various markers when applied in the initial 24 hours after admission to the hospital. After detailed review of the literature, the authors conclude that there is no single tool that serves as the optimal predictor of severity. There are, however, data supporting the use of certain tests to improve upon the clinician's early predictive ability on the subsequent course of AP. These include an APACHE II score greater than seven, IL-6 at the time of admission, and urine TAP, urine trypsinogen-2,and serum PMN-elastase at 24 hours (Box 1). These markers will only be able to help the clinician's predictive ability if they can be performed locally and if the results can be available in a timely manner. Future research should focus on markers such as procalcitonin, IL-8, IL-I ra, sTNFR,CAPAP, PLA-2, novel markers, and the combined use of more than one marker. The conventional research approach in predicting severity used in the last15 years has limitations and appears to have reached its maximal potential. Novel conceptions and approaches, such as identification of genetic polymorphisms that predispose to severe course and complications of AP, are needed for a quantum step forward.

Predictors of severity and necrosis in acute pancreatitis

C-reactive protein remains the single standard biochemical marker for predicting the severity of AP. Because the combination of clinical-physiological scores and CRP provide good information at 48 hours, research has focused on the predictive ability of various markers when applied in the initial 24 hours after admission to the hospital. After detailed review of the literature, the authors conclude that there is no single tool that serves as the optimal predictor of severity. There are, however, data that support the use of certain tests to improve upon the clinician's early predictive ability on the subsequent course of AP. These include an APACHE II score greater than 7 and IL-6 at the time of admission, and urine TAP, urine trypsinogen-2, and serum PMN elastase at 24 hours (Table 4). These markers only will be able to help the clinician's predictive ability if they can be performed locally and if the results can be available ina timely manner. Future research should focus on promising markers such as procalcitonin, IL-8, IL-I ra, sTNFR, CAPAP, PLA-2, novel markers, and the combined use of more than one marker. The conventional research approach in predicting severity used in the last 15 years has limitations and appears to have reached its maximal potential. Novel conceptions and approaches, such as identification of genetic polymorphisms that predispose to severe course and complications of AP or other approaches are needed for a quantum step forward.

Useful markers for predicting severity and monitoring progression of acute pancreatitis

BACKGROUND

The main problem in staging acute pancreatitis is the lack of accurate predictors of disease severity and of markers for progression of acute pancreatitis.

METHODS

We reviewed the literature for all candidate markers of acute pancreatitis and graded their usefulness and practicability for prediction of severe pancreatitis and for monitoring disease progression.

RESULTS

Several markers can differentiate mild and severe cases of acute pancreatitis with a high positive predictive value. Trypsinogen activation peptide and procalcitonin show significant differences in patients with mild and severe disease already on admission. While most parameters peak early and decrease rapidly thereafter, C-reactive protein (CRP), phospholipase A(2), procalcitonin and serum amyloid A are reliable predictors with persistently elevated levels in severe disease. CRP is still the reference parameter of all predictors indicating severe disease and pancreatic necrosis. So far, no single parameter has been developed which is suitable for early prediction of infected pancreatic necrosis.

CONCLUSION

Of all markers available today, CRP is the 'gold standard' in predicting the severity of acute pancreatitis, but procalcitonin seems to be a promising tool to monitor the progression of the disease. CRP has already been established in clinical routine. For procalcitonin, a practicable assay is also available and could easily be adopted into clinical routine.

Severe acute pancreatitis is related to increased early urinary levels of the activation Peptide of pancreatic phospholipase A(2)

BACKGROUND/AIM

In acute pancreatitis, it is believed that generalized activation of pancreatic zymogens leads to autodigestion of the pancreas and if excessive to systemic organ injury. Under physiological circumstances, secretory phospholipase A(2) type I (sPLA(2)-I) is activated by trypsinogen, but the extent of this activation in acute pancreatitis is unclear. The aim of this study was to assess time course and level of activation of sPLA(2)-I and trypsinogen in acute pancreatitis, relative to severity.

METHODS

246 patients were enrolled into a prospective European multicenter study. 137 patients had mild and 35 had severe acute pancreatitis, and there were 74 control patients. Urinary samples were taken on admission and at 6-hour intervals for 48 h, then every 12 h up to 72 h, and finally daily for at least 5 days for measurement of the activation peptide of sPLA(2)-I (pro-phosphatase A(2); PROP) and trypsinogen activation peptide.

RESULTS

The median maximum PROP values were significantly elevated 48 h after symptom onset in patients with severe acute pancreatitis [1.52 (95% CI 0.8-2.9) nmol/l] as compared with patients with mild acute pancreatitis [0.72 (0.55-1) nmol/l, p = 0.002] and controls [0.49 (0.22-1.2) nmol/l, p = 0.001], but not before or after this time point. The best cutoff point for urinary PROP to predict overall severity was >1 nmol/l < or =48 h after symptom onset (negative predictive value = 88%), but the PROP levels failed to predict the development of multi-organ dysfunction.

CONCLUSIONS

Activation of sPLA(2)-I is associated with the early pathogenesis of acute pancreatitis, but not in the development of distant organ damage. This observation raises questions as to the theory of generalized zymogen activation being a principle mechanism involved in the pathogenesis of distant organ damage in acute pancreatitis.

Trypsinogen-2 and trypsinogen activation peptide (TAP) in urine of patients with acute pancreatitis

BACKGROUND AND AIMS

There is an obvious clinical need for a simple test that can identify patients at risk of developing severe acute pancreatitis. In this work we compared urinary trypsinogen-2 with urinary trypsinogen activation peptide (TAP) and serum C-reactive protein (CRP) for early differentiation between mild and severe acute pancreatitis.

PATIENTS AND METHODS

The study population consisted of 127 consecutive patients with acute pancreatitis of whom 29 had severe disease. Urinary trypsinogen-2 was measured by a quantitative immunofluorometric assay and TAP by a competitive immunoassay. Serum CRP was determined by immunoturbidimetry.

RESULTS

The sensitivity and specificity to identify severe acute pancreatitis on admission was 72% and 81% for urinary trypsinogen-2, 64% and 82% for urinary TAP, and 29% and 93% for serum CRP, respectively. At 24 h after admission, the values were 82% and 78% for urinary trypsinogen-2, 52% and 92% for urinary TAP, and 84% and 72% for serum CRP, respectively. Receiver-operating characteristics curve analysis showed that the area under the curve was larger for urinary trypsinogen-2 than for urinary TAP and serum CRP on admission and 24 h after admission. On admission the positive likelihood ration for urinary trypsiongen-2 was 3.7, for urinary TAP 3.6, and 4.3 for serum CRP, respectively. The corresponding negative likelihood ratios were 0.34, 0.43, and 0.76, respectively.

CONCLUSION

Urinary trypsinogen-2 was superior to serum CRP and as god as or even better than urinary TAP and in the early prediction of disease severity in acute pancreatitis. These results suggest that it could be a valuable adjunct in the early assessment of the severity of acute pancreatitis.

Protease-activated receptor 2-mediated vasodilatation in humans in vivo: role of nitric oxide and prostanoids

BACKGROUND

Systemic hypotension as a consequence of vascular dysfunction is a well-recognized and important feature of critical illness. Although serine protease activation has been implicated as a cause of vascular dysfunction in systemic inflammation, the mechanism is unknown. Recently, a class of receptors with an entirely novel mechanism of action, protease-activated receptors (PARs), has been identified that would explain the link between protease activation and systemic hypotension. Our aim was to test the hypothesis that in vivo activation of protease-activated receptor 2 (PAR-2) in humans would mediate vasodilatation.

METHODS AND RESULTS

For these first-in-human studies, an activating peptide for the human PAR-2 receptor was synthesized and administered to healthy volunteers. Using both the dorsal hand vein technique and forearm plethysmography, we studied the effects of PAR-2 activation in human blood vessels and investigated the mechanism of vasodilation. Activation of PAR-2 receptors in vivo dilated human blood vessels in a dose-dependent manner, and the effects were reduced by inhibition of both nitric oxide and prostanoid synthesis

CONCLUSIONS

These findings demonstrate that serine protease activity can cause human vasodilation and provide a possible explanation of why serine protease activation in critical illness is associated with vascular dysfunction.

Serum levels of procarboxypeptidase B and its activation peptide in patients with acute pancreatitis and non-pancreatic diseases

BACKGROUND

Carboxypeptidase B from the pancreatic gland may exist in three different molecular and immunoreactive forms: the proenzyme, the active enzyme, and the activation peptide.

AIMS

To investigate levels of procarboxypeptidase B (proCAPB) and its activation peptide in serum in acute pancreatitis to test the accuracy of these two variables as markers for the diagnosis of acute pancreatitis and for prediction of pancreatic necrosis. To elucidate whether leakage of proenzymes and activation of proenzymes reflect two different pathophysiological events in acute pancreatitis.

METHODS

Sera from patients with acute pancreatitis (n=85) and acute abdominal pain of non-pancreatic origin (n=53) were analysed for proCAPB and its activation peptide. Patients with pancreatitis were divided into necrotising (n=33) and oedematous attacks (n=52) using contrast enhanced computed tomography. Accuracy was determined using receiver operating characteristic curve analysis.

RESULTS

Immunoreactive carboxypeptidase B activation peptide (ir-CAPAP) concentration in serum on admission was 0.7 nmol/l (0-18.1) in patients with oedematous pancreatitis compared with 5.8 nmol/l (1.9-34) in patients with later development of pancreatic necrosis. Elevated levels of the activation peptide on admission correlated with an accuracy of 92% to later development of pancreatic necrosis. Ir-proCAPB concentration in serum on admission was 16.0 nmol/l (1.4-50.5) in all patients with acute pancreatitis versus 0.3 nmol/l (0-3.6) in patients with non-pancreatic acute abdominal disorders. Cases with oedematous pancreatitis had ir-proCAPB levels of 15.4 nmol/l (1.4-50.5) versus 19.1 nmol/l (2.7-36.1) in cases with later development of pancreatic necrosis. Measurement of the proenzyme can thus be useful for the diagnosis of acute pancreatitis (accuracy 99%) but levels did not correlate with later development of pancreatic necrosis (accuracy 56%).

CONCLUSION

Leakage of proenzymes occurs in acute pancreatitis, irrespective of severity, while development of pancreatic necrosis occurs only when there is activation of the proenzymes.

Urinary trypsinogen activation peptide is more accurate than hematocrit in determining severity in patients with acute pancreatitis: a prospective study

OBJECTIVE

The management of patients with acute pancreatitis is complicated by the inability to distinguish mild from severe disease during the early stages. It has been previously shown that urinary trypsinogen activation peptide (TAP) and hematocrit (Hct) may serve as early predictors of severity in patients with acute pancreatitis. To establish which marker is more accurate in the determination of severity in patients with acute pancreatitis, a prospective study was performed.

METHODS

A consecutive series of patients admitted with pain consistent with acute pancreatitis and an amylase of three times the upper limit of normal were included. The admission and 24-h Hct was obtained. A urine sample was obtained within 12 h of admission. Urinary TAP was determined using a modified solid phase ELISA. Severity was defined by the Atlanta Symposium, as the presence of organ failure and/or pancreatic necrosis.

RESULTS

Fifty-eight consecutive patients with acute pancreatitis participated. There were 33 men and 25 women with a mean age of 60 +/- 19. Thirty-nine patients had mild disease; 19 had severe disease. Urinary TAP was elevated in 26 patients. All patients with severe pancreatitis were correctly identified as having severe disease by an elevated urinary TAP (sensitivity 100%, specificity 77%). The admission Hct was higher than 47 in only three patients, all with mild disease. Of the patients with a rise in Hct, eight had mild disease, and only one had severe disease. Using a Hct of 44 as a cutoff did not affect the accuracy. There was no association between a rise in Hct and failure of Hct to decrease in the determination of severity.

CONCLUSIONS

In comparison to admission Hct, urinary TAP was more accurate in determining severity in patients with acute pancreatitis by Atlanta, APACHE II, and Ranson criteria. We conclude that urinary TAP is a more accurate predictor of severity in patients with acute pancreatitis compared with Hct. Urinary TAP should be used to determine severity in patients early in the course of acute pancreatitis.

New laboratory tests in acute pancreatitis

Acute pancreatitis (AP) is a common disease with wide variation of severity. The diagnosis of AP is usually based on high serum amylase or lipase values but the accuracy of these methods is considered unsatisfactory. One in five of the patients develops a severe disease and carries a considerable risk of development of organ failure and high mortality. Early detection of patients with severe AP and especially those with increased risk of organ failure is importance since such patients seem to benefit from treatment in an intensive care unit started as soon as possible after presentation. In addition to enzymological methods, increasing interest has been focused on laboratory markers reflecting the level of inflammatory response in AP. At present, in routine clinical work the most commonly used severity marker is serum C-reactive protein, the concentration of which rises too slowly to be used for early prediction of severity. New therapies aiming at modifying the course of systemic inflammation in AP are being developed and therefore monitoring the patient's immune inflammatory status is needed. In this review article we present the current knowledge of laboratory tests, which has been evaluated for diagnostic and prognostic purposes in AP.

Acute pancreatitis in Soweto, South Africa: relationship between trypsinogen load, trypsinogen activation, and fibrinolysis

OBJECTIVE

It is not known why acute pancreatitis in Soweto, South Africa, pursues an aggressive course. We sought clues from circulating trypsinogen load at admission as marker of initial acinar injury, trypsinogen activation using the carboxypeptidase B activation peptide as surrogate, proteinase inhibitors, the coagulation-fibrinolysis axis, indicators of inflammation, oxidative stress markers, and antioxidant status. This article reports on the first four aspects.

METHODS

The study involved 24 consecutive patients with a first attack. All of them were admitted within 24 h, and 22 were alcoholic. Urine was analyzed for anionic trypsinogen and the carboxypeptidase B activation peptide. Serum was tested for anionic and cationic trypsinogen, alpha1 proteinase inhibitor and alpha2 macroglobulin. Plasma from a subset was assayed for soluble fibrin, cross-linked fibrin degradation products (surrogates for thrombin and plasmin activity, respectively), and tissue-type plasminogen activator and inhibitor.

RESULTS

Soweto controls had higher serum anionic trypsinogen (p = 0.004) and plasminogen activator:inhibitor ratio (p = 0.047) than U.K. controls. The outcome of acute pancreatitis was mild in 17 but severe in seven with three deaths, two on day 2. In mild pancreatitis, intense plasmin activity (p < 0.001) accompanied the surge in trypsinogen, especially anionic (p < 0.001), but without increased thrombin activity and in five patients without trypsinogen activation. In severe pancreatitis, further significant increments in plasmin activity and trypsinogens were accompanied by increased thrombin activity (p = 0.013) and trypsinogen activation (p = 0.046). There was no correlation between surrogates of plasmin and thrombin activity, or between either and the carboxypeptidase B activation peptide, which showed a curvilinear relationship to total serum trypsinogen.

CONCLUSIONS

The aggressive nature of alcoholic acute pancreatitis in Soweto seems to reflect early profound fibrinolysis, which precedes coagulation and is initially independent of trypsin. Subclinical acinar-cell injury and a profibrinolytic diathesis in outwardly healthy Sowetans may predispose to this problem.

Serum amyloid A is a better early predictor of severity than C-reactive protein in acute pancreatitis

BACKGROUND

Serum amyloid A (SAA) is an early and sensitive marker of the extent of tissue trauma and inflammation. The aim of this study was to compare the early prognostic accuracy of SAA with that of serum C-reactive protein (CRP) in acute pancreatitis.

METHODS

In a prospective multicentre trial, plasma SAA and CRP levels were measured in patients with severe and mild acute pancreatitis, and in a control group with acute abdominal pain. Plasma samples were collected on admission and at 6-h intervals for 48 h, every 12 h between 48 and 72 h, then daily for 5 days. Plasma SAA was measured by a new enzyme-linked immunosorbent assay and CRP was measured by immunoturbidometry.

RESULTS

There were 137 patients with mild and 35 with severe acute pancreatitis, and 74 control patients. SAA levels were significantly higher in patients with severe acute pancreatitis than in those with mild acute pancreatitis, on admission, at 24 h or less after symptom onset, and subsequently. Whereas plasma CRP concentration was also significantly higher in patients with severe acute pancreatitis on admission, it failed to distinguish mild from severe acute pancreatitis until 30-36 h after symptom onset. SAA levels predicted severity (sensitivity 67 per cent, specificity 70 per cent, negative predictive value 89 per cent, mean(s.d.) area under curve 0.7(0.05)) significantly better than CRP (57 per cent, 60 per cent, 84 per cent, 0.59(0.06) respectively) on admission (P = 0.02) and at 24 h following symptom onset (area under curve 0.65(0.09) versus 0.58(0.09) respectively; P < or = 0.02).

CONCLUSION

Plasma SAA concentration is an early marker of severity in acute pancreatitis and is superior to CRP estimation on hospital admission and at 24 h or less after symptom onset. This study suggests that plasma SAA concentration is clinically useful, with the potential to replace CRP in the management of acute pancreatitis.

Serum amyloid A is a better early predictor of severity than C-reactive protein in acute pancreatitis

BACKGROUND

Serum amyloid A (SAA) is an early and sensitive marker of the extent of tissue trauma and inflammation. The aim of this study was to compare the early prognostic accuracy of SAA with that of serum C-reactive protein (CRP) in acute pancreatitis.

METHODS

In a prospective multicentre trial, plasma SAA and CRP levels were measured in patients with severe and mild acute pancreatitis, and in a control group with acute abdominal pain. Plasma samples were collected on admission and at 6-h intervals for 48 h, every 12 h between 48 and 72 h, then daily for 5 days. Plasma SAA was measured by a new enzyme-linked immunosorbent assay and CRP was measured by immunoturbidometry.

RESULTS

There were 137 patients with mild and 35 with severe acute pancreatitis, and 74 control patients. SAA levels were significantly higher in patients with severe acute pancreatitis than in those with mild acute pancreatitis, on admission, at 24 h or less after symptom onset, and subsequently. Whereas plasma CRP concentration was also significantly higher in patients with severe acute pancreatitis on admission, it failed to distinguish mild from severe acute pancreatitis until 30-36 h after symptom onset. SAA levels predicted severity (sensitivity 67 per cent, specificity 70 per cent, negative predictive value 89 per cent, mean(s.d.) area under curve 0.7(0.05)) significantly better than CRP (57 per cent, 60 per cent, 84 per cent, 0.59(0.06) respectively) on admission (P = 0.02) and at 24 h following symptom onset (area under curve 0.65(0.09) versus 0.58(0.09) respectively; P < or = 0.02).

CONCLUSION

Plasma SAA concentration is an early marker of severity in acute pancreatitis and is superior to CRP estimation on hospital admission and at 24 h or less after symptom onset. This study suggests that plasma SAA concentration is clinically useful, with the potential to replace CRP in the management of acute pancreatitis.

Prognostic factors in acute pancreatitis

The assessment of the severity of acute pancreatitis (AP) is a critical early step in its management, as severity of AP predicts prognosis. A range of options are available for assessment of severity in AP, including clinical evaluation, standardized prognostic criteria, computed tomography (CT), and biochemical markers. Clinical assessment has limited accuracy for predicting severity early in the course of AP. Therefore, additional assessment using biochemical and radiologic criteria in combination with standardized criteria is appropriate to determine severity and prognosis in AP; a strategy emphasizing daily assessment of severity should be used. The APACHE II is the scoring system of choice for evaluating severity in AP, although it remains an imperfect tool. Computed tomographic grading of AP and the development of the CT severity index allow for heightened accuracy in the prediction of severity. C-Reactive protein is the standard for serum marker assessment of severity and prognosis in AP; other markers, including interleukin-6, polymorphonuclear elastase, and trypsinogen activation peptide, hold promise. The focus of this review is to examine the role of diagnostic tests in evaluating severity and predicting prognosis among patients with AP and to provide a diagnostic algorithm for initial management.

Predicting the Severity of Acute Pancreatitis by Rapid Measurement of Trypsinogen-2 in Urine

Background: Early identification of patients at risk of developing a severe attack of acute pancreatitis (AP) is of great importance because rapid therapeutic interventions improve outcome. At a cutoff of 50 μg/L, trypsinogen-2 measured by a rapid urinary dipstick is a sensitive and specific diagnostic test in AP. The trypsinogen-2 concentration correlates with the severity of the disease, and a test with a higher cutoff might therefore be useful for prediction of disease severity.

Methods: We increased the detection limit of the urinary trypsinogen-2 test strip (Actim Pancreatitis) from 50 μg/L to 2000 μg/L and evaluated the prognostic value of this test. The results were compared with those obtained with serum C-reactive protein and the acute physiology and chronic health evaluation II (APACHE II) score. The study population consisted of 150 consecutive patients with AP (42 with severe disease).

Results: The sensitivity of the rapid urinary test strip (detection limit, 2000 μg/L) for prediction of severe AP, both on admission and at 24 h, was 62%; specificities were 87% and 85%, respectively, positive predictive values were 65% and 62%, and negative predictive values were 85% and 85%. C-Reactive protein had a sensitivity of only 38% on admission, but at 24 h, it was 83%; specificities were 90% and 70%, respectively, whereas positive predictive values were 59% and 52%, and NPVs were 79% and 91%, respectively. On admission the positive-likelihood ratio for the urinary trypsinogen-2 test strip was 4.8, and at 24 h it was 4.2; for C-reactive protein, the values were 3.7 and 2.7, respectively.

Conclusions: The urinary trypsinogen-2 dipstick is a simple and rapid method for prediction of severe acute pancreatitis.

Review of feline pancreatitis part two: clinical signs, diagnosis and treatment

In the past decade pancreatitis has become recognised as a significant disease in the cat. Chronic, mild pancreatitis is often associated with more commonly diagnosed diseases such as inflammatory bowel disease or cholangitis/cholangiohepatitis. Furthermore, acute pancreatitis with similar complications to those seen in dogs is now diagnosed more frequently in cats. Unfortunately, the clinical signs and clinicopathological findings in cats with pancreatitis are often non-specific and vague. The lack of specific signs often results in a diagnosis being made only when the veterinary surgeon has a strong index of suspicion for pancreatitis and vigorously pursues that diagnosis. Pancreatitis is an important disease in cats, has been implicated as a potential cause of diabetes mellitus, and when present complicates the treatment of diabetes and other intra-abdominal diseases in cats.

A comparison of serum trypsinogen-2 and trypsin-2-alpha1-antitrypsin complex with lipase and amylase in the diagnosis and assessment of severity in the early phase of acute pancreatitis

OBJECTIVE

The aim of the study was to compare the recently introduced laboratory markers trypsinogen-2 and trypsin-2-alpha1 antitrypsin complex (trypsin-2-AAT) in serum with lipase and amylase in the diagnostic and prognostic evaluation of patients with acute pancreatitis (AP).

METHODS

The analytes were measured on admission in 64 consecutive patients with AP and in 30 controls with acute abdominal disease of extrapancreatic origin. Twenty-one patients had severe and 43 mild AP. As reference methods we used serum amylase and C-reactive protein.

RESULTS

In subjects with AP, elevated trypsinogen-2 values (> or = 90 microg/L) were observed in 63 patients (98%), trypsin-2-AAT values (> or = 12 microg/L) in 64 patients (100%), lipase values (> or = 200 U/L) in 64 patients (100%), and amylase values (> or = 300 IU/L) in 62 patients (97%). The diagnostic accuracy of the markers was evaluated by receiver operating characteristic (ROC) analysis. On admission, trypsinogen-2, trypsin-2-AAT, lipase, and amylase differentiated patients with AP from controls with high accuracy and ROC analyses showed similar areas under the ROC curves (AUC) for trypsinogen-2 (AUC 0.960), trypsin-2-AAT (0.948), lipase (AUC 0.947), and amylase (AUC 0.930). For differentiation between severe and mild AP, trypsin-2-AAT (AUC 0.805) was slightly better than trypsinogen-2 (AUC 0.792), and they were both clearly better than lipase (AUC 0.583), C-reactive protein (AUC 0.519), or amylase (AUC 0.632) (p < 0.05).

CONCLUSIONS

All the markers studied showed high accuracy for differentiating between AP and extrapancreatic diseases. However, trypsinogen-2 and trypsin-2-AAT displayed the best accuracy for predicting a severe AP already at admission, which makes these markers superior for clinical purposes.

The Ratio of Trypsin-2-α1-Antitrypsin to Trypsinogen-1 Discriminates Biliary and Alcohol-induced Acute Pancreatitis

Background: Rapid determination of the etiology of acute pancreatitis (AP) enables institution of appropriate treatment. We evaluated the ability of trypsinogen-1, trypsinogen-2, trypsin-1-α1-antitrypsin (AAT), and trypsin-2-AAT in serum to identify the etiology of AP.

Methods: The study consisted of 67 consecutive patients with AP admitted to Helsinki University Central Hospital. Forty-two had alcohol-induced AP, 16 had biliary AP, and 9 had unexplained etiology. Serum samples were drawn within 12 h after admission. Trypsinogen-1, trypsinogen-2, trypsin-1-AAT, and trypsin-2-AAT were determined by time-resolved immunofluorometric assays. Logistic regression was used to estimate the ability of the serum analytes to discriminate between alcohol-induced and biliary AP. The validity of the tests was evaluated by ROC curve analysis.

Results: Patients with alcohol-induced AP had higher median values of trypsin-1-AAT (P = 0.065), trypsinogen-2 (P = 0.034), and trypsin-2-AAT (P &lt;0.001) than those with biliary AP, who had higher values of amylase (P = 0.002), lipase (P = 0.012), and alanine aminotransferase (P = 0.036). The ratios of trypsin-2-AAT to trypsinogen-1, lipase, or amylase efficiently discriminated between biliary and alcohol-induced AP (areas under ROC curves, 0.92–0.96).

Conclusions: Trypsinogen-2 and trypsin-2-AAT are markedly increased in AP of all etiologies, whereas trypsinogen-1 is increased preferentially in biliary AP. The trypsin-2-AAT/trypsinogen-1 ratio is a promising new marker for discrimination between biliary and alcohol-induced AP.

Time course profile of serum trypsinogen-2 and trypsin-2-alpha1-antitrypsin in patients with acute pancreatitis

BACKGROUND

Trypsinogen-2 and the trypsin-2-alpha1-antitrypsin complex are recently introduced new laboratory markers for acute pancreatitis. They show high sensitivity and specificity for acute pancreatitis on admission, but little is known on their time course profiles.

METHODS

The serum concentrations of trypsinogen-2 and trypsin-2-alpha1-antitrypsin were monitored in 92 patients with verified acute pancreatitis. The follow-up period was 42 days in patients with severe acute pancreatitis (N = 73) and 9 days in mild disease (N = 19).

RESULTS

On admission the mean serum concentration of trypsinogen-2 was 2880 microg/l in severe and 920 microg/l in mild acute pancreatitis. These values were 32- and 10-fold the upper reference limit, respectively. Trypsin-2-alpha1-antitrypsin concentrations were 1250 microg/l (100-fold the upper reference limit) and 635 microg/l (52-fold), respectively. The differences were statistically significant (P = 0.026-0.001). The concentrations of trypsinogen-2 and trypsin-2-alpha1-antitrypsin decreased gradually during the follow-up period, but they remained elevated for the entire study period in patients with severe and mild disease.

CONCLUSIONS

The time course profile of trypsinogen-2 and trypsin-2-alpha1-antitrypsin is favorable for diagnosing acute pancreatitis. The elevation starts within hours after the onset of the disease and it is very steep. Both markers remain elevated longer than amylase and the magnitude of the elevation correlates with the severity of the disease. This is further evidence to support the use of trypsinogen-2 and trypsin-2-alpha1-antitrypsin for the evaluation of patients suspected of having acute pancreatitis.

Early prediction of severity in acute pancreatitis by urinary trypsinogen activation peptide: a multicentre study

BACKGROUND

There is a pressing clinical requirement for an early simple test of severity in acute pancreatitis. We investigated the use of an assay of trypsinogen activation peptide (TAP).

METHODS

We undertook a multicentre study in 246 patients (172 with acute pancreatitis [35 with severe disease], 74 controls). We assessed the predictive value of urinary TAP concentrations measured by a validated competitive immunoassay. We compared the results with those for plasma C-reactive protein and three clinicobiochemical scoring systems. TAP and C-reactive protein concentrations were analysed at set times after symptom onset and compared with the clinicobiochemical systems scores at key times during hospital stay.

FINDINGS

At 24 h after symptom onset, the median urinary TAP concentration was 37 nmol/L (IQR 17-110) for severe and 15 nmol/L (5-35) for mild disease (p<0.001). The respective values for plasma C-reactive protein were 24 mg/L (3-34) and 25 mg/L (6-75; p=0.208). The sensitivity, specificity, positive predictive, and negative predictive values of the test to show severe acute pancreatitis compared with mild acute pancreatitis at 24 h were: for TAP (>35 nmol/L), 58%, 73%, 39%, and 86%, respectively, and for C-reactive protein (>150 mg/L), 0%, 90%, 0%, and 75%. 48 h after admission the values for the clinicobiochemical scoring systems were: APACHE II (> or =8), 56%, 64%, 30%, and 85%; Ranson score (> or =3), 89%, 64%, 38%, and 96%; and Glasgow score (> or =3), 77%, 75%, 44%, and 93%. At 48 h, the values for C-reactive protein were 86%, 61%, 37%, and 94% and for TAP were 83%, 72%, 44%, and 94%. Combined testing of C-reactive protein and TAP was not superior to TAP alone for accuracy.

INTERPRETATION

Urinary TAP provided accurate severity prediction 24 h after onset of symptoms. This single marker of severity in acute pancreatitis deserves routine clinical application.

Proteases in the evaluation of pancreatic function and pancreatic disease

This paper reviews the role of pancreatic proteases (focusing upon trypsin, chymotrypsin and elastase) in the diagnosis and management of chronic pancreatic insufficiency (CPI), emphasizing advances over the last 5 years. Some important novel aspects of these enzymes in acute pancreatitis are also described, including their role in diagnosis and their interaction with cholecystokinin in the pathogenesis of the disease. The recent interest in these enzymes as agents promoting the spread of cancer in animals and human subjects is also described. A hierarchical approach has been taken to explore the advantages and limitations of tests in different source materials: serum, feces, duodenal aspirate, and non-invasive pancreatic function tests. The practical usefulness of fecal elastase-1 and of fecal chymotrypsin concentrations in diagnosis and management of CPI, respectively, is one of the major lessons to be learned from analysis of the recent literature, and forms the principal message of this review.

Reliable screening for acute pancreatitis with rapid urine trypsinogen-2 test strip

BACKGROUND

This study was designed to evaluate the validity of a new rapid urinary trypsinogen-2 test strip (Actim Pancreatitis) for detection of acute pancreatitis in patients with acute abdominal pain.

METHODS

A total of 525 consecutive patients presenting with abdominal pain at two emergency units was included prospectively and tested with the Actim Pancreatitis test strip. Urine trypsinogen-2 concentrations were also determined by a quantitative method. The diagnosis and assessment of severity of acute pancreatitis was based on raised serum and urinary amylase levels, clinical features and findings on dynamic contrast-enhanced computed tomography.

RESULTS

In 45 patients the diagnosis of acute pancreatitis could be established. The Actim Pancreatitis test strip result was positive in 43 of them resulting in a sensitivity of 96 per cent. Thirty-seven false-positive Actim Pancreatitis test strips were obtained in patients with non-pancreatic abdominal pain resulting in a specificity of 92 per cent. Nine patients with severe acute pancreatitis were all detected by the dipstick.

CONCLUSION

A negative Actim Pancreatitis strip result excludes acute pancreatitis with high probability. Positive results indicate the need for further evaluation, i.e. other enzyme measurements and/or radiological examinations. The test is easy and rapid to perform, unequivocal in its interpretation and can be used in healthcare units lacking laboratory facilities.

Time-resolved Immunofluorometric Assay of Trypsin-1 Complexed with α1-Antitrypsin in Serum: Increased Immunoreactivity in Patients with Biliary Tract Cancer

Background: Increased serum concentrations of trypsin immunoreactivity occur in patients with biliary tract cancer. To characterize this trypsin, we developed a sensitive time-resolved immunofluorometric assay for trypsin-1 complexed with α1-antitrypsin (AAT) and studied the concentrations of this complex in sera from healthy individuals (n = 130) and patients with benign biliary disease (n = 32), biliary tract cancer (n = 17), pancreatic cancer (n = 27), and hepatocellular cancer (n = 12).

Methods: We used a trypsin-1-specific monoclonal antibody on the solid phase and a europium-labeled polyclonal antibody to AAT as tracer. The detection limit was 0.42 μg/L. The validity of the trypsin-1-AAT test for detection of biliary tract cancer was compared with trypsin-2-AAT and CA19-9.

Results: Increased concentrations of trypsin-1-AAT (&gt;33 μg/L) were found in 76% of patients with biliary tract cancer, and the concentrations were significantly higher than in those with benign biliary disease (P &lt;0.0001). The median concentration of trypsin-1-AAT in serum from patients with biliary tract cancer was 3.7-fold higher than in healthy controls, 2.6-fold higher than in patients with benign biliary tract disease, 1.7-fold higher than in patients with pancreatic cancer, and 2.0-fold higher than in patients with hepatocellular cancer.

Conclusions: Of the markers studied, trypsin-1-AAT had the largest area (0.83) under the receiver operating curve in differentiating biliary tract cancer from benign biliary tract disease. Our results suggest that trypsin-1-AAT is a new potential marker for biliary tract cancer.

Membrane-protease interactions. III: A consideration of the difference in binding potential of pancreatic proteases to erythrocytes and erythrocyte ghosts

Trypsin and chymotrypsin readily bind to human erythrocyte ghosts and to resealed right-side-out ghosts, but not to intact erythrocytes, as followed with [3H]trypsin and [3H]chymotrypsin and with cold proteases in a caseinolytic assay. The proteases freely reacted with casein in the presence of intact cells. Trypsin activated trypsinogen over an 8-hr time course at a faster rate in the presence of erythrocytes than in the absence thereof, after a slight initial delay. Trypsinogen did not bind to intact erythrocytes, thereby behaving comparably to trypsin. These results suggest that different microenvironments exist about the erythrocyte ghosts and the intact erythrocytes, thereby permitting the proteases to bind to the former but not to the latter. Hence, in the absence of considerable ghosts in circulating blood, which may mask the binding site of the proteases, the proteases may be more readily accessible for interaction with circulating serpins, leading to inactivation of the proteases and protection from their degradative potential. The presence of the serpins in circulating blood may assist in the control of the degradative power of the pancreatic proteases in pancreatitis and may negatively modulate such processes as thrombosis, activation of the complement system, and vascular remodeling.