The effect of moderate sedation on exocrine pancreas function in normal healthy subjects: a prospective, randomized, cross-over trial using the synthetic porcine secretin stimulated Endoscopic Pancreatic Function Test (ePFT)

Delayed Processing of Secretin-Induced Pancreas Fluid Influences the Quality and Integrity of Proteins and Nucleic Acids

OBJECTIVES

Endoscopic pancreatic function tests are used to diagnose pancreatic diseases and are a viable source for the discovery of biomarkers to better characterize pancreatic disorders. However, pancreatic fluid (PF) contains active enzymes that degrade biomolecules. Therefore, we tested how preservation methods and time to storage influence the integrity and quality of proteins and nucleic acids.

METHODS

We obtained PF from 9 subjects who underwent an endoscopic pancreatic function test. Samples were snap frozen at the time of collection; after 1, 2, and 4 hours on ice; or after storage overnight at 4°C with or without RNase or protease inhibitors (PIs). Electrophoresis and mass spectrometry analysis determined protein abundance and quality, whereas nucleic acid integrity values determined DNA and RNA degradation.

RESULTS

Protein degradation increased after 4 hours on ice and DNA degradation after 2 hours on ice. Adding PIs delayed degradation. RNA was significantly degraded under all conditions compared with the snap frozen samples. Isolated RNA from PF-derived exosomes exhibited similar poor quality as RNA isolated from matched PF samples.

CONCLUSIONS

Adding PIs immediately after collecting PF and processing the fluid within 4 hours of collection maintains the protein and nucleic acid integrity for use in downstream molecular analyses.

Endoscopic Pancreatic Function Testing (ePFT) in Children: A Position Paper From the NASPGHAN Pancreas Committee

Endoscopic pancreatic function testing (ePFT) is one of the few ways to directly diagnose exocrine pancreatic insufficiency, and considerable confusion regarding indications, utility, and interpretation of the test remains. This position paper of the Pancreas Committee of the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition reviews the history and indications for ePFT in children. We compare various methods in current practice and determine their strengths and limitations, and based on data from children and adults we provide guidance on a protocol on how to perform ePFT in children. Lastly, we pose areas in need of further research relating to ePFT in children.

Assessment of Exocrine Pancreatic Function During Endoscopy in Children

This article will review briefly the physiology of pancreatic enzyme secretion and the role of stimulated endoscopic testing for assessing exocrine pancreatic function. Published studies in both the pediatric and adult literature are reviewed. The technique and utility of endoscopic pancreatic function testing as the method of choice in the differential diagnosis of pancreatic disorders in childhood is described. Finally, emerging, clinically useful markers that can be measured in the pancreatic fluid will be described.

Standard Operating Procedures for Biospecimen Collection, Processing, and Storage: From the Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer

High-quality and well-annotated biorepositories are needed to better understand the pathophysiology and biologic mechanisms of chronic pancreatitis (CP) and its consequences. We report a methodology for the development of a robust standard operating procedure (SOP) for a biorepository based on the experience of the clinical centers within the consortium to study Chronic Pancreatitis, Diabetes and Pancreas Cancer Clinical Centers (CPDPC), supported by the National Cancer Institute and the National Institute for Diabetes and Digestive and Kidney Diseases as a unique multidisciplinary model to study CP, diabetes, and pancreatic cancer in both children and adults. Standard operating procedures from the CPDPC centers were evaluated and consolidated. The literature was reviewed for standard biorepository operating procedures that facilitated downstream molecular analysis. The existing literature on biobanking practices was harmonized with the SOPs from the clinical centers to produce a biorepository for pancreatic research. This article reports the methods and basic principles behind the creation of SOPs to develop a biorepository for the CPDPC. These will serve as a guide for investigators developing biorepositories in pancreas research. Rigorous and meticulous adherence to standardized biospecimen collection will facilitate investigations to better understand the pathophysiology and biologic mechanisms of CP, diabetes, and pancreatic cancer.

A study of the clinical utility of a 20-minute secretin-stimulated endoscopic pancreas function test and performance according to clinical variables

BACKGROUND AND AIMS

Direct pancreas juice testing of bicarbonate, lipase, or trypsin after stimulation by secretin or cholecystokinin is used to determine exocrine function, a surrogate for diagnosing chronic pancreatitis (CP). Endoscopic pancreas function tests (ePFTs), where a peak bicarbonate concentration (PBC) ≥80 mEq/L in pancreas juice is considered normal, are now used more frequently. In this ePFT, aspirates start 35 minutes after secretin administration because pancreas output peaks 30 minutes after secretagogue administration. The performance of ePFT in a cohort of patients with a presumptive diagnosis of CP referred to a pancreas clinic for consideration of an intervention including total pancreatectomy and islet autotransplantation was studied, compared with EUS, ERCP, histology, and consensus diagnosis. The effect of sedation, narcotic use, aspirate volume, body mass index, age, and proton pump inhibitors (PPIs) on test performance is reported.

METHODS

After a test dose, synthetic human secretin was administered intravenously, and 30 minutes later sedation was achieved with midazolam and fentanyl or propofol. A gastroscope was advanced to the major papilla where 4 continuous aspiration samples were performed at 5-minute intervals in sealed bottles. PBC ≥80 mEq/L was normal.

RESULTS

Eighty-one patients had ePFTs from August 2010 through October 2015. Twenty-seven patients (33%) were diagnosed with CP. Eighteen of the 27 patients with CP and 1 of the 54 patients without CP had an abnormal ePFT, producing a sensitivity of 66% (95% CI, 46.0-83.5), specificity 98% (95% CI, 90.1-99.9), positive predictive value 94.7% (95% CI, 74-99.9), and negative predictive value 85.5% (95% CI, 74.2-93.1). ERCP and PBC concordance was generally poor, but none of the patients without CP had major EUS changes, and only 3 patients with a PBC <80 mEq/L had a normal EUS. The PBC was affected by narcotics and PPI use.

CONCLUSION

A 20-minute ePFT after secretin administration had a marginal sensitivity for diagnosis of CP. The diagnosis of CP should not rely on a single study and certainly not a PFT. The duodenal aspirate volume did not correlate with the PBC, which contrasts with current secretin-enhanced MRCP knowledge; therefore, further studies on this subject are warranted. Neither type of sedation, BMI, nor age affected test performance. Narcotics and PPIs may affect the PBC, so borderline results should be interpreted with caution in these groups.

Total pancreatectomy for recurrent acute and chronic pancreatitis: a critical review of patient selection criteria

PURPOSE OF REVIEW

Critical review of the indications for total pancreatectomy and highlight limitations in current diagnostic criteria for chronic pancreatitis.

RECENT FINDINGS

The diagnosis of noncalcific chronic pancreatitis remains controversial because of an overreliance on nonspecific imaging and laboratories findings. Endoscopic ultrasound, s-magnetic resonance cholangiopancreatography, and/or endoscopic pancreatic function testing are often used to diagnose noncalcific chronic pancreatitis despite the fact that there is no gold standard for this condition. Abdominal pain is not specific for chronic pancreatitis and is more likely to be encountered in patients with functional gastrointestinal disorders based on the high incidence of these conditions. The duration of pain and opioid analgesic use results in central sensitization that adversely affects pain outcomes after total pancreatectomy. An alcoholic cause is associated with poorer pain outcomes after total pancreatectomy.

SUMMARY

The lack of a gold standard for noncalcific chronic pancreatitis limits the diagnostic accuracy of imaging and laboratory tests. The pain of chronic pancreatitis is nonspecific and is affected by duration, preoperative opioid use, and cause. These factors will need to be considered in the development of future selection criteria for this morbid surgery.

Secretin-Enhanced Magnetic Resonance Cholangiopancreatography for Assessing Pancreatic Secretory Function in Children

OBJECTIVE

To assess the accuracy and interrater reproducibility of measurements of pancreatic secretory function by magnetic resonance cholangiopancreatography in response to secretin administration and to describe our experience using the technique to noninvasively assess pancreatic secretory function in a pediatric population.

STUDY DESIGN

In the accuracy study, phantoms with varying fluid volume (47-206 mL) were imaged using the clinical quantification sequence. Fluid volume was measured by image segmentation (ImageJ). Measurement accuracy was expressed in terms of error (absolute and percent) relative to known fluid volume. In the reproducibility study and clinical experience, 31 patients with suspected pancreatic disease underwent 33 secretin-enhanced magnetic resonance cholangiopancreatography exams. Two-dimensional T2-weighted, fat-saturated single shot fast spin echo sequences were acquired before and after secretin injection (0.2 µg/kg, max 16 µg). Secreted fluid volume (postsecretin minus presecretin) was independently measured by 2 blinded reviewers. Between reviewer measurement reproducibility was assessed based on correlation (Spearman) and bias (Bland-Altman analysis).

RESULTS

For the accuracy study, fluid volumes were measured with mean volume errors of -0.3 to +12.5 mL (percent error -0.03% to +9.0%). For the reproducibility study, the mean secreted fluid volumes measured by reviewer 1 and reviewer 2 were 79.1 ± 54.3 mL (range 5.5-215.4) and 77.2 ± 47.1 mL (range 6.7-198.1 mL), respectively. Measured secreted fluid volumes were very strongly correlated (r = 0.922) between reviewers with a bias of only 1.9 mL (95% limits of agreement -40.5 to 44.2).

CONCLUSIONS

Measurement of fluid volume by magnetic resonance imaging is highly accurate with <10% (<13 mL) error in measured volume. Measurements of pancreatic secreted fluid volume in response to secretin by magnetic resonance cholangiopancreatography are highly reproducible with a bias of <2 mL between reviewers.

Comparison of Combined Endoscopic Ultrasonography and Endoscopic Secretin Testing With the Traditional Secretin Pancreatic Function Test in Patients With Suspected Chronic Pancreatitis: A Prospective Crossover Study

OBJECTIVE

We aimed to determine the feasibility and accuracy of a combined endoscopic ultrasonography (EUS) with a shortened pancreatic function testing (sEUS) for structural and functional assessment using a single instrument in patients with suspected chronic pancreatitis (CP).

METHODS

We completed a prospective crossover study, enrolling patients with suspected CP. Patients who underwent both traditional 1-hour secretin pancreatic function test (sPFT) and sEUS were included in the analysis. We compared study results for test concordance and for correlation of peak bicarbonate concentrations.

RESULTS

Eleven (64.7%) of 17 patients had concordant sPFT and sEUS findings when the cutoff for peak bicarbonate was 80 mEq/L. Six patients had discordant findings with a negative sPFT and positive sEUS. This poor concordance suggests that sEUS is an unreliable functional test. Lowering the sEUS cutoff to 70 mEq/L resulted in improved concordance (64.7% vs 70.6%). Finally, there was no significant correlation between peak bicarbonate concentrations (r = 0.47; 95% confidence interval, -0.02 to 0.79) in these 2 functional tests.

CONCLUSIONS

We demonstrate poor concordance between sPFT and sEUS suggesting that a combined shortened functional and structural test using a single instrument may not be a feasible test for diagnosis of suspected CP when a cutoff of 80 mEq/L is used.

Endoscopic Pancreas Fluid Collection: Methods and Relevance for Clinical Care and Translational Science

Pancreatic secretions have an important role in the regulation of a normal nutritional state but can be altered owing to a variety of pathophysiological mechanisms in the context of exocrine pancreatic disease. The development of an endoscopic technique for collection of pancreatic fluid, termed endoscopic pancreatic function testing, has led to improved understanding of these alterations and is particularly helpful to characterize chronic pancreatitis. In addition, investigators have found endoscopically collected pancreatic fluid to be a valuable biofluid for the purposes of translational science. Techniques such as proteomic, cytokine, genetic mutation, DNA methylation, and microRNA analyses, among others, can be utilized to gain a better understanding of the molecular characteristics of chronic pancreatitis and other pancreatic diseases. Endoscopic collection of pancreatic fluid is safe and relatively straightforward, permitting opportunities for longitudinal analysis of these translational markers throughout the course of disease. This manuscript summarizes our current knowledge of pancreatic fluid, with an emphasis on proper techniques for sample collection and handling, its clinical utility, and preliminary observations in translational science.

ESPGHAN and NASPGHAN Report on the Assessment of Exocrine Pancreatic Function and Pancreatitis in Children

The purpose of this clinical report is to discuss several recent advances in assessing exocrine pancreatic insufficiency (EPI) and pancreatitis in children, to review the array of pancreatic function tests, to provide an update on the inherited causes of EPI, with special emphasis on newly available genetic testing, and to review newer methods for evaluating pancreatitis.

Quantification of pancreatic function using a clinically feasible short endoscopic secretin test

OBJECTIVES

Clinical and morphological criteria are not precise enough to diagnose early chronic pancreatitis (CP). We investigated if short endoscopic pancreas function testing as a part of routine upper endoscopy could improve clinical diagnostics.

METHODS

Patients with suspected CP underwent modified secretin-stimulated upper endoscopy (short endoscopic secretin test, or EST). Duodenal juice was collected during 15 minutes starting 30 minutes after stimulation. A modified scoring system for CP after Layer with bicarbonate and fecal elastase 1 (FE1) was used. We tested with receiver operating characteristic curves the diagnostic accuracy of bicarbonate and FE1 and with analysis of variance how precise the 2 parameters can discriminate the groups.

RESULTS

Fifty-two patients aged 19 to 67 years and 25 healthy controls aged 19 to 64 years were included. Twenty-four patients fulfilled the modified Layer Score for CP or non-CP. The overall accuracy of the EST versus FE1 test was 85%/71%, with positive and negative predictive values of 100%/79% and 80%/69%, respectively.

CONCLUSIONS

Short EST is rapid and easy to perform and can be incorporated in daily routines. We demonstrate that EST is superior to FE1 in the assessment of pancreatic insufficiency and may prove to be useful in diagnosing early or mild CP.

Defining the accuracy of secretin pancreatic function testing in patients with suspected early chronic pancreatitis

OBJECTIVES

The diagnosis of chronic pancreatitis in patients with characteristic symptoms but normal pancreatic imaging is challenging. Assessment of pancreatic function through secretin pancreatic function testing (SPFT) has been advocated in this setting, but its diagnostic accuracy is not fully known.

METHODS

This was a retrospective review of patients who received SPFT at our tertiary care institution between January 1995 and December 2008 for suspected chronic pancreatitis. For all patients, medical records were reviewed for evidence of subsequent development of chronic pancreatitis by imaging and/or pathology. Patients were then categorized as "true positive" or "true negative" for chronic pancreatitis based on follow-up imaging or histologic evidence.

RESULTS

In all, 116 patients underwent SPFT. Of the 27 patients who tested positive, 7 were lost to follow-up. Of the remaining 20 SPFT-positive patients, 9 (45%) developed radiologic or histologic evidence of chronic pancreatitis after a median of 4 years (1-11 years). Of the 89 patients who had negative SPFT testing, 19 were lost to follow-up. Of the remaining 70 patients, 2 were eventually diagnosed with chronic pancreatitis based on subsequent imaging/histology after a median follow-up period of 7 years (3-11 years). The sensitivity of the SPFT in diagnosing chronic pancreatitis was 82% with a specificity of 86%. The positive predictive value (PPV) of chronic pancreatitis was 45% with a negative predictive value (NPV) of 97%.

CONCLUSIONS

In patients with suspected early chronic pancreatitis and normal pancreatic imaging, SPFT is highly accurate at ruling out early chronic pancreatitis with a NPV of 97%.

An automated analyzer provides clinically concordant results to manual back titration for quantitation of bicarbonate in pancreatic juice

OBJECTIVES

Secretin pancreatic function tests play an important role in the diagnosis of chronic pancreatitis. Back titration is the standard method for measurement of bicarbonate in pancreatic juice but is time consuming and manually performed. Use of an autoanalyzer for this purpose is not validated.

METHODS

Bicarbonate concentrations in secretin-stimulated pancreatic juice specimens were quantitated by manual back titration, a clinical chemistry autoanalyzer (automated bicarbonate, Roche Cobas c501, Roche Diagnostics, Indianapolis, Ind), and a blood gas analyzer (calculated bicarbonate, GEM 3000, Instrumentation Laboratories, Bedford, Mass). Kappa statistic analysis, Bland-Altman analysis, and Lin concordance correlation coefficients were calculated.

RESULTS

Ninety specimens from 31 subjects were included. Using a bicarbonate concentration of 80 mEq/L as a cutoff value, there was poor agreement between back titration and calculated bicarbonate (κ = 0.188); however, only 1 specimen showed discrepancy between back titration and automated bicarbonate (κ = 0.977). The limit of agreement between the back titration and automated bicarbonate was -9.0 to + 8.3 mEq/L. The Lin concordance correlation coefficient between the 2 methods was 0.931 (P < 0.001).

CONCLUSIONS

There is strong concordance between manual back titration and chemistry autoanalyzer methods for measurement of bicarbonate concentrations in pancreatic juice. Autoanalyzers may replace back titration for this purpose. Blood gas analyzers are unsuitable.

Adipokines and cytokines in human pancreatic juice: unraveling the local pancreatic inflammatory milieu

BACKGROUND

Differential adipokine expression in obesity influences the inflammatory milieu, and may explain in part obesity's negative impact on pancreatic disease. Pancreatic juice analysis may provide a good means to evaluate the local pancreatic inflammatory milieu. The presence of adipokines in pancreatic juice is unknown.

AIMS

This proof-of-concept study was designed to determine the presence of adipokines and cytokines in human pancreatic juice.

METHODS

With institutional review board approval, pancreatic juice was obtained from ten patients with a broad range of diagnoses at the time of endoscopic retrograde cholangiopancreatography. Pancreatic juice was assayed using enzyme-linked immunosorbent assay (ELISA) for insulin, the proinflammatory adipokine leptin, the anti-inflammatory adipokine adiponectin, and the inflammatory mediators interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and monocyte chemoattractant protein-1 (MCP-1). Correlation between adipokine and inflammatory mediator expression was determined by linear regression analysis. Data are presented as mean +/- standard error of the mean (SEM); P < 0.05 was considered statistically significant.

RESULTS

Leptin (0.16 +/- 0.05 ng/ml) and adiponectin (0.63 +/- 0.02 microg/ml) were both present, as were the inflammatory mediators IL-6 (112.6 +/- 28.1 pg/ml), TNF-alpha (49.0 +/- 18.8 pg/ml), and MCP-1 (32.2 +/- 0.9 pg/ml). Paradoxically, the expression of the anti-inflammatory adipokine adiponectin correlated strongly with that of the proinflammatory cytokine IL-6 (R(2) = 0.98, P < 0.001).

CONCLUSIONS

This report is the first to describe adipokine expression in human pancreatic juice. Human pancreatic juice inflammatory mediators and adipokines may provide an important measurement of the local pancreatic inflammatory milieu.

Diagnosis of chronic pancreatitis: Functional testing

The diagnosis of chronic pancreatitis is mainly based on imaging procedures (e.g., endoscopic ultrasound, magnetic resonance cholangiopancreatography (MRCP) and magnetic resonance imaging (MRI)). Functional testing in this context could however be still of help in cases of inconclusive morphological findings. With this aim, only the secretin-pancreozymin test and the endoscopic test are sensitive enough. The role of other function tests, such as the quantification of the coefficient of fat absorption (CFA) and the (13)C-mixed triglyceride breath test, is limited to the diagnosis of exocrine pancreatic insufficiency with maldigestion. Faecal elastase and chymotrypsin are still useful for detecting reduction of pancreatic secretion in patients with different pancreatic diseases and patients' compliance to enzyme replacement therapy, respectively. Other tests used in the past (e.g., Lundh test, N-benzoyl-tryosyl para-aminobenzoic acid (NBT-PABA) test, pancreolauryl test and amino acid consumption test) are neither available now nor useful for clinical practice. This article reviews the different pancreatic function tests commercially available and their role in clinical practice.

Magnetic resonance cholangiopancreatography reports in the evaluation of chronic pancreatitis: a need for quality improvement

BACKGROUND

Numerous publications from academic centers suggest that magnetic resonance cholangiopancreatography (MRCP) can diagnose early chronic pancreatitis (CP) and assess pancreatic secretory reserve/function. However, the rigorous composite interpretation methods and quantitative secretory dynamics reported in these studies are not routinely measured in clinical practice. Therefore, the utility of routine MRCP reports in the clinical setting is unknown.

STUDY DESIGN

Cross-sectional study of patients referred to a tertiary center who underwent both MRCP and endoscopic pancreas function testing (ePFT) for assessment of chronic pancreatitis and abdominal pain.

AIMS

To compare MRCP and sMRCP reports to a reference standard pancreas function test for diagnosis of chronic pancreatitis.

METHODS

Source population: patients seen within a pancreas clinic at a tertiary referral center. MRCP and sMRCP reports were reviewed to record pancreas duct (dilation, side-branch changes), parenchyma enhancement (T(1), T(2) signal) and physiologic response (duodenal filling, pancreas duct response) to secretin. ePFT was categorized based on previously published data (normal peak bicarbonate >80 mEq/l). Referent values were calculated for MRCP and sMRCP using secretin ePFT as gold standard.

RESULTS

A total of 69 patients were identified (mean age 43.5 +/- 12; 65.2% female). 28 (40.6%) patients had abnormal ePFT based on their peak bicarbonate level. The mean bicarbonate values in the abnormal PFT and normal PFT groups were 59 +/- 13.9 and 95.3 +/- 12.6 mEq/l, respectively. Peak bicarbonate decreased with severity of chronic pancreatitis on MRCP (p = 0.0016). There was fair agreement of MRCP and ePFT (kappa 0.335 [0.113, 0.557]). The pre-stimulation pancreas duct changes reported were found to be the only predictor of abnormal pancreas function (p = 0.002). The post-stimulation findings of duodenal filling (p = 0.47), T(2)enhancement (p = 0.21) or change in pancreas duct caliber (p = 0.3) reported did not improve MRCP agreement with ePFT. Overall diagnostic accuracy, sensitivity and specificity were 70, 85 and 46%, respectively, for MRCP reports using ePFT as the gold standard.

CONCLUSIONS

Pancreas ductal features described on routine MRCP reports correlate with abnormal pancreas function. Current MRCP reports should be standardized to include all radiologic information available in hopes of predicting early chronic pancreatitis.

Pancreatic function testing: here to stay for the 21st century

The diagnosis of Chronic Pancreatitis (CP) is based on the detection of abnormal structure or function of the diseased pancreas. The pancreatic function tests more accurately determine the presence of CP than tests of structure, especially for early stage disease. The function tests can be divided into two categories: non-invasive and invasive. The invasive "tube" tests can reliably detect mild, early CP, but are only available at a few referral centers and tend to be poorly tolerated by patients. The non-invasive tests are easy to obtain, but tend to perform poorly in patients with early, mild disease. Therefore, no one test is useful in all clinical situations, and a detailed understanding of the rational, pathophysiologic basis, strengths, and limitations of various tests is needed. This review highlights the role of various pancreatic function tests in the diagnosis of CP including fecal fat analysis, fecal elastase, fecal chymotrypsin, serum trypsin, the secretin stimulation test, the cholecystokinin (CCK) stimulation test, the combined secretin-CCK stimulation test, the intraductal and endoscopic secretin stimulation tests, and the functional magnetic resonance imaging of the pancreas after secretin stimulation.

A prospective crossover study comparing secretin-stimulated endoscopic and Dreiling tube pancreatic function testing in patients evaluated for chronic pancreatitis

BACKGROUND

Direct pancreatic function tests (PFT) are conventionally performed with use of double-lumen "Dreiling" collection tubes. We have developed an endoscopic collection method (ePFT) that eases the performance of these tests.

OBJECTIVE

Our aim was to compare the bicarbonate results obtained from the secretin ePFT and Dreiling PFT methods in patients evaluated for chronic pancreatitis.

DESIGN

A prospective crossover design was used to compare the PFT methods.

SETTING

Tertiary care referral center.

PATIENTS AND INTERVENTIONS

Twenty-four patients undergoing an evaluation for chronic pancreatitis underwent the secretin-stimulated ePFT and Dreiling PFT methods on separate days.

MAIN OUTCOME MEASUREMENTS

Duodenal fluid bicarbonate concentrations and estimated bicarbonate outputs were compared.

RESULTS

The mean difference in peak bicarbonate concentration (Dreiling PFT minus ePFT) was 7 mEq/L (SD 20) and not statistically significant (P = .11). A good correlation in peak bicarbonate concentrations (r = 0.74, 95% CI, 0.48-0.88) and estimated bicarbonate output (r = 0.78, 95% CI, 0.54-0.90) was observed between the two PFT methods.

LIMITATION

The sensitivities and specificities of the secretin ePFT and Dreiling PFT could not be compared because of the lack of a histologic gold standard.

CONCLUSION

The secretin ePFT yields results similar to those of the Dreiling PFT in patients evaluated for chronic pancreatitis.

Comparative proteomic analysis of human pancreatic juice: methodological study

Pancreatic cancer is the most lethal of all the common malignancies. Markers for early detection of this disease are urgently needed. Here, we optimized and applied a proteome analysis of human pancreatic juice to identify biomarkers for pancreatic cancer. Pancreatic juice samples, devoid of blood or bile contamination, were collected from patients with pancreatic cancer (n = 5), benign pancreatic diseases (n = 6), or cholelithiasis (n = 3) during endoscopic retrograde cholangiopancreatography (ERCP). After ultramembrane centrifugation sample preparation, pancreatic juice proteins were separated by 2-DE and identified by MALDI-TOF-MS. A 2-DE dataset of pancreatic juice from patients with cholelithiasis was established, consisting of 76 protein spots representing 22 different proteins. Disease-associated obstruction of the pancreatic duct strongly effected the protein composition of pancreatic juice. Concurrently, pancreatic juice from patients with pancreatic cancer was compared to nonmalignant controls with comparable obstruction of pancreatic ducts. Seven protein spots were identified that consistently appeared at changed levels in pancreatic juice from patients with pancreatic cancer. In conclusion, comparative proteomic analysis of human pancreatic juice can be used to identify biomarkers of pancreatic cancer.

The efficiency of endoscopic pancreatic function testing is optimized using duodenal aspirates at 30 and 45 minutes after intravenous secretin

OBJECTIVES

The endoscopic secretin test (ePFT) takes an hour to perform, limiting its practicality for routine use. We sought to determine which timed endoscopic collections best predict the peak bicarbonate concentration from full hour-long test.

METHODS

A cross-sectional study was performed of all ePFTs performed at our institution from 2000 to 2004. We compared 7 theoretical shortened tests [4-single collections (15, 30, 45, or 60 minutes after secretin) and 3-dual collections (15/30, 30/45, 45/60 minutes after secretin)] to the full test and to each other using multivariate linear and Deming regression models.

RESULTS

The bicarbonate results of 240 ePFTs were analyzed. The dual 30/45-minute collection was the optimal method based on the closest agreement with the full test (94%). Deming regression reveals the 30/45 estimate to be the best combination from an analytic perspective, owing to its lack of significant proportional bias and minimal constant bias (5.1 mEq/L) as compared to the reference test. Use of the 30/45 method with the adjusted cutpoint 75 mEq/L produces very good specificity (93%) for ruling in exocrine insufficiency.

CONCLUSIONS

A dual timed aspiration at 30 and 45 minutes can be used to screen for pancreatic exocrine insufficiency in patients with abdominal pain, simplifying the use of the ePFT in clinical practice.

Endoscopy-based pancreatic function tests

Direct pancreatic function tests have been the mainstay for the diagnosis of pancreatic exocrine insufficiency. Due to their cumbersome nature and limited availability there is a continuous search for a rapid and inexpensive test of pancreatic function. Endoscopic approaches to evaluate pancreatic function have been assessed. This article critically reviews the current evidence related to this novel approach, outlining some elements for further refinement.

Where have all the dreiling tubes gone?

The direct measurement of pancreatic function remains the best tool for diagnosing chronic pancreatitis, especially if imaging tests are normal or inconclusive. The most effective means of measuring pancreatic function is the standard hormone stimulation test using secretin. Traditionally, direct pancreatic function testing involves the fluoroscopic placement of an oroduodenal tube and collection of duodenal fluid containing pancreatic secretions after administration of a standardized dose of secretin and/or CCK. The test is time-consuming and tedious to perform, and placement of the oroduodenal tube is often difficult for the person performing the test and uncomfortable for the patient. Bicarbonate concentration typically has been measured by back-titration, requiring specialized equipment no longer found in most hospital clinical chemistry laboratories. For these reasons, the direct testing of pancreatic function after secretin stimulation has become a much admired but rarely performed test, currently done in only a few centers in the United States. In this issue of the Journal, Stevens et al. report on a cross-over study of secretin-stimulated endoscopic pancreatic function test (ePFT) and dreiling tube pancreatic function test (D-PFT) in healthy subjects and demonstrate that the accuracy of the ePFT is comparable to that of the D-PFT (17). They have demonstrated the relative simplicity and reliability of ePFT, bringing it closer to the diagnostic armamentarium of the practicing physician. We may have lost the Dreiling tube but, in its place, gained a "gold standard" which will be more widely used.

A randomized crossover study of secretin-stimulated endoscopic and dreiling tube pancreatic function test methods in healthy subjects

OBJECTIVES

We have developed an endoscopic method of secretin endoscopic pancreatic function testing (ePFT) to simplify duodenal fluid collection. Validation of the ePFT requires a direct comparison to the traditional PFT using a Dreiling tube (DT). Our aim was to compare bicarbonate concentrations [HCO3-] obtained by the ePFT and DT methods in healthy subjects (HS).

METHODS

HS were randomized to either DT or ePFT, then crossed over to the other test after a minimum 1-wk washout. An age/weight-based sedation bolus was used for each test. DT protocol: Endoscopic placement of a DT was confirmed by fluoroscopy. After a baseline 15-min collection and administration of IV synthetic secretin, fluid was continuously collected in 15-min aliquots for an hour. ePFT protocol: Endoscopy was performed using a 6-mm endoscope. After gastric aspiration and discard and IV secretin, duodenal aspirates were obtained every 15-min for an hour. Fluid specimens were auto-analyzed for [HCO3-].

RESULTS

Twelve HS were enrolled (6F, mean age 37 yr). The difference in [HCO3-] between the two methods was not significant at the 0-, 30-, 45-, or 60-min collections. An excellent correlation in peak [HCO3-] was observed (R2 = 0.84, p < 0.001). Using a peak [HCO3-] cutpoint 80 mEq/L, there was 100% agreement between the methods; using cutpoint 90 mEq/L, there was 83% agreement.

CONCLUSIONS

The accuracy of the ePFT is similar to DT: There were minimal differences in [HCO3-] at each of the timed collections and at peak. There is an excellent correlation in peak [HCO3-] and high level of diagnostic agreement between the tests.