Amphipathic Liponecrosis Impairs Bacterial Clearance and Causes Infection During Sterile Inflammation.

BACKGROUND & AIMS: Although transient bacteremia is common during dental and endoscopic procedures, infections developing during sterile diseases like acute pancreatitis (AP) can have grave consequences. We examined how impaired bacterial clearance may cause this transition. METHODS: Blood samples from patients with AP, normal controls, and rodents with pancreatitis or those administered different nonesterified fatty acids (NEFAs) were analyzed for albumin-unbound NEFAs, microbiome, and inflammatory cell injury. Macrophage uptake of unbound NEFAs using a novel coumarin tracer were done and the downstream effects-NEFA-membrane phospholipid (phosphatidylcholine) interactions-were studied on isothermal titration calorimetry. RESULTS: Patients with infected AP had higher circulating unsaturated NEFAs; unbound NEFAs, including linoleic acid (LA) and oleic acid (OA); higher bacterial 16S DNA; mitochondrial DNA; altered ß-diversity; enrichment in Pseudomonadales; and increased annexin V-positive myeloid (CD14) and CD3-positive T cells on admission. These, and increased circulating dead inflammatory cells, were also noted in rodents with unbound, unsaturated NEFAs. Isothermal titration calorimetry showed progressively stronger unbound LA interactions with aqueous media, phosphatidylcholine, cardiolipin, and albumin. Unbound NEFAs were taken into protein-free membranes, cells, and mitochondria, inducing voltage-dependent anion channel oligomerization, reducing ATP, and impairing phagocytosis. These were reversed by albumin. In vivo, unbound LA and OA increased bacterial loads and impaired phagocytosis, causing infection. LA and OA were more potent for these amphipathic interactions than the hydrophobic palmitic acid. CONCLUSIONS: Release of stored LA and OA can increase their circulating unbound levels and cause amphipathic liponecrosis of immune cells via uptake by membrane phospholipids. This impairs bacterial clearance and causes infection during sterile inflammation.

Pathophysiology and Biomarker Potential of Fatty Acid Ethyl Ester Elevation During Alcoholic Pancreatitis.

BACKGROUND & AIMS: The role of fatty acid ethyl esters (FAEEs) during human alcoholic pancreatitis is unknown. We compared FAEEs levels with their nonesterified fatty acids (NEFAs) precursors during alcohol intoxication and clinical alcoholic pancreatitis. The pathophysiology underlying FAEEs increase and their role as diagnostic biomarkers for alcoholic pancreatitis was investigated. METHODS: A prospective blinded study compared FAEEs, NEFAs, and ethanol blood levels on hospitalization for alcoholic pancreatitis (n = 31), alcohol intoxication (n = 25), and in normal controls (n = 43). Serum FAEEs were measured at admission for nonalcoholic pancreatitis (n = 75). Mechanistic cell and animal studies were done. RESULTS: Median FAEEs were similarly elevated during alcohol intoxication (205 nmol/L; 95% confidence interval [CI], 71.8-515 nmol/L, P < .001) and alcoholic pancreatitis (103.1 nmol/L; 95% CI, 53-689 nmol/L, P < .001) vs controls (1.7 nmol/L; 95% CI, 0.02-4.3 nmol/L) or nonalcoholic pancreatitis (8 nmol/L; 95% CI, 1.1-11.5 nmol/L). Alcoholic pancreatitis increased serum NEFAs (1024 ± 710 µmol/L vs 307 ± 185 µmol/L in controls, P < .05). FAEEs comprised 0.1% to 2% of the parent NEFA concentrations. FAEES correlated strongly with NEFAs independent of ethanol levels in alcoholic pancreatitis but not during alcohol intoxication. On receiver operating characteristic curve analysis for diagnosing alcoholic pancreatitis, the area under the curve for serum FAEEs was 0.87 (95% CI, 0.78-0.95, P < .001). In mice and cells, alcohol administration transiently increased all FAEEs. Oleic acid ethyl ester was the only FAEE with a sustained increase up to 24 hours after intraperitoneal oleic acid plus ethanol administration. CONCLUSIONS: The sustained, alcohol-independent, large (20- to 50-fold) increase in circulating FAEEs during alcoholic pancreatitis results from their visceral release and mirrors the 2- to 4-fold increase in parent NEFA. The large areas under the curve of FAEEs on receiver operating characteristic curve analysis supports their role as alcoholic pancreatitis biomarkers.

Poor 'real-life' negative predictive value of cross-sectional imaging in obstructive jaundice.

BACKGROUND: Cross-sectional imaging remains the first-line test for obstructive jaundice despite high miss rates for pancreatobiliary tumours. Improvements in resolution and slice thickness of spiral computed tomography/magnetic resonance imaging/magnetic resonance cholangiopancreatography promised to increase accuracy. OBJECTIVE: To assess whether the post-test probability of neoplasm is truly altered by the presence or absence of a mass on computed tomography/magnetic resonance imaging in obstructive jaundice. METHODS: The institutional endoscopic ultrasound (EUS) database was retrospectively reviewed to stratify patients presenting to EUS over a two-year period for obstructive jaundice (suspicious for malignancy) according to their pre-EUS imaging results. The primary analysis involved the calculation of the positive predictive value and negative predictive value (NPV) of imaging with 95% binomial CIs. Test performance of EUS/fine-needle aspiration (FNA) was also calculated. Final diagnosis was determined by positive cytology/histology; negative EUS was supplemented by clinical follow-up. RESULTS: The positive predictive value (n = 51) and NPV (n = 53) of pre-EUS imaging was 98% (95% CI 90% to 100%) and 9% (95% CI 3% to 21%), respectively (accuracy 53%), with post-test suspicion of malignancy similar between imaging-positive and -negative groups. EUS demonstrated a mass in 96% of imaging-positive cases versus 85% in imaging-negative cases (exact P = 0.09). Malignant or suspicious FNA cytology was obtained with EUS in 92% of the imaging-positive group, and 62% of the imaging-negative group (75% of subgroup with FNA) (P < 0.001). CONCLUSION: Lack of a definite mass on pre-EUS imaging had low NPV, and was clearly not sufficiently accurate or reassuring in this clinical setting. In suspicious obstructive jaundice, EUS with FNA has a high diagnostic yield regardless of the findings of pre-EUS cross-sectional imaging and, as such, EUS may be a more reasonable first-line test in this high-suspicion setting.

Endoscopic ultrasound-guided fine-needle aspiration with on-site cytopathology versus core biopsy: a comparison of both techniques performed at the same endoscopic session.

BACKGROUND: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) with bedside cytopathology is the gold standard for assessment of pancreatic, subepithelial, and other lesions in close proximity to the gastrointestinal tract, but it is time-consuming, has certain diagnostic limitations, and bedside cytopathology is not widely available. AIMS: The goal of this study is to compare the diagnostic yield of EUS-guided FNA with on-site cytopathology and EUS-guided core biopsy. METHODS: Twenty-six patients with gastrointestinal mass lesions requiring biopsy at a tertiary medical center were included in this retrospective analysis of a prospective cohort. Two core biopsies were taken using a 22 gauge needle followed by FNA guided by a bedside cytopathologist at the same endoscopic session. The diagnostic yield and test characteristics of EUS core biopsy and EUS FNA with bedside cytopathology were examined. RESULTS: The mean number of passes was 3.2 for FNA, and the mean procedure time was 39.4 minutes. The final diagnosis was malignant in 92.3 %. Sensitivity and specificity were 83 % and 100 %, respectively, for FNA, and 91.7 % and 100 %, respectively, for core biopsy. Diagnostic accuracy was 92.3 % for FNA and 84.6 % for core biopsy. The two approaches were in agreement in 88.4 % with a kappa statistic of 0.66 (95 % confidence interval 0.33 - 0.99). CONCLUSIONS: An approach using two passes with a core biopsy needle is comparable to the current gold standard of FNA with bedside cytopathology. The performance of two core biopsies is time-efficient and could represent a good alternative to FNA with bedside cytopathology.

Accuracy of contrast-enhanced harmonic EUS with a second-generation perflutren lipid microsphere contrast agent (with video).

BACKGROUND: EUS-FNA has limitations in cancer diagnosis/staging. New contrast agents, transducers, and processors have improved the potential of contrast-enhanced harmonic (CEH)-EUS. OBJECTIVE: To determine optimal settings and preliminary accuracy of CEH-EUS by using a second-generation perflutren lipid microsphere contrast agent and a prototype linear echoendoscope. DESIGN: Prospective, comparative, pilot study. SETTING: Tertiary-care medical center. PATIENTS: This study involved patients with esophageal/pancreatic/liver tumors or adenopathy. INTERVENTION: Contrast agent was injected (10 µL/kg intravenously in 1-2 doses), and the mechanical index was optimized over 5 cases (0.3). Intermittent/continuous imaging was used with extended pure harmonic detection. MAIN OUTCOME MEASUREMENTS: Before-contrast and after-contrast predictions of neoplasia (5-point Likert scale). The reference standard was positive tissue or 6-month follow-up. Perfusion factors (sequence, pattern, washout) were noted, and phases were video recorded (arterial, venous, and postvenous). RESULTS: Thirty sites (7 nodes and 16 pancreatic and 7 nonpancreatic masses) were imaged in 21 patients; 21 of 30 had FNA, and 5 had surgery. Four cases (13.3%) were rated as undecided/indeterminate with EUS (vs 1 [3.3%] with CEH-EUS; P = .35). Twenty-four cases with confirmed diagnoses (12 malignant and 12 benign) were used for test performance: positive/negative predictive values for CEH-EUS were 80.0% (95% confidence interval, 51.9%-95.7%)/100.0% (95% confidence interval, 63.0%-100.0%) versus 84.6%/100.0% for EUS. Accuracies, counting "undecided" (1 in CEH-EUS and 4 in EUS) as incorrect, were 83.3% and 79.2%. In 2 cases, management would change significantly: (1) liver hemangioma, avoiding FNA; and (2) mediastinal "cyst" confirmed as solid. LIMITATIONS: Small sample. Tissue not always available. CONCLUSION: CEH-EUS adds minimal imaging time and is accurate, with small improvement over EUS. Added information in vascular and cystic lesions can potentially change management.

Multicenter comparison of the interobserver agreement of standard EUS scoring and Rosemont classification scoring for diagnosis of chronic pancreatitis.

BACKGROUND: EUS has less than optimal interobserver agreement for the diagnosis of chronic pancreatitis. The newly developed Rosemont consensus scoring system includes weighted criteria and stricter definitions for individual features. OBJECTIVE: The primary aim was to compare the interobserver agreement of standard and Rosemont scoring. SETTING: Multiple tertiary-care institutions. INTERVENTION: Fifty EUS videos were interpreted by 14 experts. Each expert interpreted the videos on two occasions: First, the videos were read by using standard scoring (9 criteria). Second, after viewing a presentation of the Rosemont classification, the same experts re-read the videos by using Rosemont scoring. MAIN OUTCOME MEASUREMENTS: Fleiss' kappa (K) statistics are reported with 95% confidence intervals (CI). RESULTS: The interobserver agreement was "substantial" (K = 0.65 [95% CI, 0.52-0.77]) for Rosemont scoring and "moderate" (K = 0.54 [95% CI, 0.44-0.66]) for standard scoring; however, the difference was not statistically significant (P = 0.12). LIMITATIONS: The sample size does not allow detection of differences in K of <0.25. CONCLUSION: Use of the Rosemont classification did not significantly increase interobserver agreement for EUS diagnosis of chronic pancreatitis compared with standard scoring.

The changing landscape of practice patterns regarding unsedated endoscopy and propofol use: a national Web survey.

BACKGROUND: Lower reimbursements for endoscopic procedures and increasing demand for screening endoscopy over the past decade have spurred efforts to increase efficiency in the performance of endoscopic procedures. Two dichotomous approaches have emerged: (1) unsedated endoscopy and (2) propofol sedation. The aim was to determine national practice patterns of unsedated endoscopy and propofol sedation, and to assess endoscopists' attitudes toward unsedated screening with an electronic survey. METHODS: A short survey was developed and then was converted to a Web-based format. All national members of the American Society for Gastrointestinal Endoscopy (ASGE) were invited via electronic mail (e-mail) to participate. Survey data were collected electronically. RESULTS: Two e-mails elicited responses to the Web survey from 18% (724) of national ASGE members contacted, within 2 weeks. Of the respondents, 45% do not routinely offer unsedated EGD and colonoscopy, and only 15% of those respondents plan to incorporate unsedated endoscopy into their practice in the next year. Of the 55% who currently perform unsedated endoscopy, 85% do no more than 25 unsedated procedures per year. Lack of patient acceptance was the most common reason cited for not offering unsedated endoscopy. Most endoscopists felt that the availability of unsedated esophagoscopy or colonoscopy would not significantly increase screening for Barrett's esophagus or colonic polyps/colorectal cancer, respectively. Routine use of propofol sedation for EGD, colonoscopy, and ERCP/EUS was reported by 19%, 22%, and 19%, respectively. Community practitioners were more likely to use propofol than those at academic centers (p < 0.0002 for all). Of those not currently using propofol, 43% plan to incorporate it into their practice within the next year. Over 70% of respondents would themselves choose to be sedated for routine endoscopic procedures. CONCLUSIONS: Electronic surveys allow for rapid distribution and data collection but suffer from a limited response rate. The survey suggests that unsedated endoscopy has limited acceptance in the United States, and, without a major intervention that affects endoscopists' attitudes, its use is not likely to increase significantly. Unsedated endoscopy will not have a great impact on endoscopic screening. In contrast, propofol sedation has already gained acceptance in the community, and the routine use of propofol in endoscopy units will likely increase in the future.