Influence of Klebsiella pneumoniae and quinolone treatment on prognosis in patients with pancreatic cancer.

BACKGROUND: An increasing body of evidence suggests that microbiota may promote progression of pancreatic ductal adenocarcinoma (PDAC). It was hypothesized that gammaproteobacteria (such as Klebsiella pneumoniae) influence survival in PDAC, and that quinolone treatment may attenuate this effect. METHODS: This was a retrospective study of patients from the Massachusetts General Hospital (USA) and Ludwig-Maximilians-University (Germany) who underwent preoperative treatment and pancreatoduodenectomy for locally advanced or borderline resectable PDAC between January 2007 and December 2017, and for whom a bile culture was available. Associations between tumour characteristics, survival data, antibiotic use and results of intraoperative bile cultures were investigated. Survival was analysed using Kaplan-Meier curves and Cox regression analysis. RESULTS: Analysis of a total of 211 patients revealed that an increasing number of pathogen species found in intraoperative bile cultures was associated with a decrease in progression-free survival (PFS) (-1·9 (95 per cent c.i. -3·3 to -0·5) months per species; P = 0·009). Adjuvant treatment with gemcitabine improved PFS in patients who were negative for K. pneumoniae (26·2 versus 15·3 months; P = 0·039), but not in those who tested positive (19·5 versus 13·2 months; P = 0·137). Quinolone treatment was associated with improved median overall survival (OS) independent of K. pneumoniae status (48·8 versus 26·2 months; P = 0·006) and among those who tested positive for K. pneumoniae (median not reached versus 18·8 months; P = 0·028). Patients with quinolone-resistant K. pneumoniae had shorter PFS than those with quinolone-sensitive K. pneumoniae (9·1 versus 18·8 months; P = 0·001). CONCLUSION: K. pneumoniae may promote chemoresistance to adjuvant gemcitabine, and quinolone treatment is associated with improved survival.

Risk of malignancy in small pancreatic cysts decreases over time.

BACKGROUND: Pancreatic cysts <15 mm without worrisome features have practically no risk of malignancy at the time of diagnosis but this can change over time. Optimal duration of follow-up is a matter of debate. We evaluated predictors of malignancy and attempted to identify a time to safely discontinue surveillance. METHODS: Bi-centric study utilizing prospectively collected databases of patients with pancreatic cysts measuring <15 mm and without worrisome features who underwent surveillance at the Massachusetts General Hospital (1988-2017) and at the University of Verona Hospital Trust (2000-2016). The risk of malignant transformation was assessed using the Kaplan-Meier method and parametric survival models, and predictors of malignancy were evaluated using Cox regression. RESULTS: 806 patients were identified. Median follow-up was 58 months (6-347). Over time, 58 (7.2%) cysts were resected and of those, 11 had high grade dysplasia (HGD) or invasive cancer. Three additional patients had unresectable cancer for a total rate of malignancy of 1.7%. Predictors of development of malignancy included an increase in size ≥2.5 mm/year (HR = 29.54, 95% CI: 9.39-92.91, P < 0.001) and the development of worrisome features (HR = 9.17, 95% CI: 2.99-28.10, P = 0.001). Comparison of parametric survival models suggested that the risk of malignancy decreased after three years of surveillance and was lower than 0.2% after five years. CONCLUSIONS: Pancreatic cysts <15  mm at the time of diagnosis have a very low risk of malignant transformation. Our findings indicate the risk decreases over time. Size increase of ≥2.5 mm/year is the strongest predictor of malignancy.

An elevated CA 19-9 is associated with invasive cancer and worse survival in IPMN.

BACKGROUND: Current guidelines for IPMN include an elevated serum carbohydrate antigen (CA) 19-9 among the worrisome features. However, the correlation of CA 19-9 with histological malignant features and survival is unclear. Serum CEA is also currently used for preoperative management of IPMN, although its measurement is not evidence-based. Accordingly, we aimed to assess the role of these tumor markers as predictors of malignancy in IPMN. METHODS: IPMN resected between 1998 and 2018 at Massachusetts General Hospital were analyzed. Clinical, pathological and survival data were collected and compared to preoperative levels of CA 19-9 and CEA. Receiver operating characteristic (ROC) and Cox regression analyses were performed considering cut-offs of 37 U/ml (CA 19-9) and 5 µg/l (CEA). RESULTS: Analysis of 594 patients showed that preoperative CA 19-9 levels > 37 U/ml (n = 128) were associated with an increased likelihood of invasive carcinoma when compared to normal levels (45.3% vs. 18.0%, P < 0.001), while there was no difference with respect to high-grade dysplasia (32.9% vs 31.9%, P = 0.88). The proportion of concurrent pancreatic cancer was higher in patients with CA 19-9 > 37 U/ml (17.2% vs 4.9%, P < 0.001). An elevated CA 19-9 was also associated with worse overall and disease-free survival (HR = 1.943, P = 0.007 and HR = 2.484, P < 0.001 respectively). CEA levels did not correlate with malignancy. CONCLUSION: In patients with IPMN, serum CA19-9 > 37 U/ml is associated with invasive IPMN and concurrent pancreatic cancer as well as worse survival, but not with high-grade dysplasia. Serum CEA appears to have minimal utility in the management of these patients.

International consensus guidelines for surgery and the timing of intervention in chronic pancreatitis.

BACKGROUND/OBJECTIVES: Chronic pancreatitis (CP) is a complex inflammatory disease with pain as the predominant symptom. Pain relief can be achieved using invasive interventions such as endoscopy and surgery. This paper is part of the international consensus guidelines on CP and presents the consensus guideline for surgery and timing of intervention in CP. METHODS: An international working group with 15 experts on CP surgery from the major pancreas societies (IAP, APA, JPS, and EPC) evaluated 20 statements generated from evidence on 5 questions deemed to be the most clinically relevant in CP. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the level of evidence available for each statement. To determine the level of agreement, the working group voted on the 20 statements for strength of agreement, using a nine-point Likert scale in order to calculate Cronbach's alpha reliability coefficient. RESULTS: Strong consensus was obtained for the following statements: Surgery in CP is indicated as treatment of intractable pain and local complications of adjacent organs, and in case of suspicion of malignant (cystic) lesion; Early surgery is favored over surgery in a more advanced stage of disease to achieve optimal long-term pain relief; In patients with an enlarged pancreatic head, a combined drainage and resection procedure, such as the Frey, Beger, and Berne procedure, may be the treatment of choice; Pancreaticoduodenectomy is the most suitable surgical option for patients with groove pancreatitis; The risk of pancreatic carcinoma in patients with CP is too low (2% in 10 year) to recommend active screening or prophylactic surgery; Patients with hereditary CP have such a high risk of pancreatic cancer that prophylactic resection can be considered (lifetime risk of 40-55%). Weak agreement for procedure choice in patients with dilated duct and normal size pancreatic head: both the extended lateral pancreaticojejunostomy and Frey procedure seems to provide equivalent pain control in patients. CONCLUSIONS: This international expert consensus guideline provides evidenced-based statements concerning key aspects in surgery and timing of intervention in CP. It is meant to guide clinical practitioners and surgeons in the treatment of patients with CP.

Intraoperative Fluid Administration and Surgical Outcomes Following Pancreaticoduodenectomy: External Validation at a Tertiary Referral Center.

BACKGROUND: While intraoperative fluid overload is associated with higher complication rates following surgery, data for pancreaticoduodenectomy are scarce and heterogeneous. We evaluated multiple prior definitions of restrictive and liberal fluid regimens and analyzed whether these affected surgical outcomes at our tertiary referral center. METHODS: Studies evaluating different intraoperative fluid regimens on outcomes after pancreatic resections were retrieved. After application of all prior definitions of restrictive and liberal fluid regimens to our patient cohort, relative risks of each outcome were calculated using all reported infusion regimens. RESULTS: Five hundred and seven pancreaticoduodenectomies were included. Nine different fluid regimens were evaluated. Two regimens utilized absolute volume cutoffs, and the remaining evaluated various infusion rates, ranging from 5 to 15 mL/kg/h. Total volume administration of >5000 mL and >6000 mL was associated with increased complications (RR 1.25 and RR 1.17, respectively) and >6000 mL with increased sepsis (RR 2.14). Conversely, a rate of <5 mL/kg/h was associated with increased risk of postoperative pancreatic fistula (POPF, RR 3.16) and sepsis (RR 3.20), <6.8 mL/kg/h with increased major morbidity (RR 1.64) and sepsis (RR 2.27), and <8.2 mL/kg/h with increased POPF (RR 2.16). No effects were observed on pulmonary complications, surgical site infections, length of stay, or mortality. CONCLUSIONS: In an uncontrolled setting with no standard intraoperative or postoperative care map, the volume of intraoperative fluid administration appears to have limited impact on early postoperative outcomes following pancreaticoduodenectomy, with adverse outcomes only seen at extreme values.

Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas).

OBJECTIVES: Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality. DESIGN: Retrospective multinational study including SCN diagnosed between 1990 and 2014. RESULTS: 2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2-200)), 9% had resection beyond 1 year of follow-up (3 years (1-20), size at diagnosis: 25 mm (4-140)) and 39% had no surgery (3.6 years (1-23), 25.5 mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1). CONCLUSIONS: After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN. TRIAL REGISTRATION NUMBER: IRB 00006477.

Frequency and significance of calcification in IPMN.

UNLABELLED: The frequency and significance of calcification in intraductal papillary mucinous neoplasms (IPMN) are unknown. We examined calcifications by computed tomography (CT) in a large cohort of IPMNs and correlated them with clinicopathologic characteristics. METHODS: Preoperative contrast-enhanced CT imaging studies of 164 patients with surgically resected IPMN were retrospectively reviewed. Morphologic characteristics of IPMN, presence and type of calcifications, their location, the degree of dysplasia and the epithelial subtype were recorded. Symptoms at the time of diagnosis, history of smoking, and alcohol consumption were obtained from medical records. RESULTS: Of the 164 IPMNs, 68 were branch duct type (Br-IPMN) and 96 main duct (MD-IPMN) or combined type (CT-IPMN); 78 (48%) had a malignant component (CIS and Invasive). Calcifications were present in 33 cases (20%). By type, 16 calcifications were punctate, 11 coarse and 9 eggshell, and by location, 15 were mural, 3 septal, 2 ductal, 1 in the solid component, and 13 in multiple locations. Calcifications were seen more frequently in larger lesions (44 mm vs 32 mm p = 0.002), and when MPD dilation was noted (70% vs 45%, p = 0.023). There was no association between presence of calcification and malignancy, epithelial subtype, or other clinical data. However, malignancy was present in 9/11 IPMN with coarse calcification (p = 0.04), suggesting this may be a worrisome feature. CONCLUSION: Calcification is found in 20% of IPMNs, and is more common in larger lesions. Although its overall presence has no correlation with malignancy, coarse calcification, when combined with other morphologic features, may be a radiologic sign of malignancy.

Preoperative cholangitis is an independent risk factor for mortality in patients after pancreatoduodenectomy for pancreatic cancer.

OBJECTIVES: Preoperative biliary stenting is required for patients with obstructive jaundice from pancreatic adenocarcinoma who are receiving neoadjuvant chemotherapy. While in most patients this approach results in durable biliary drainage, some patients develop cholangitis during neoadjuvant treatment. Further, several studies have shown that preoperative cholangitis in patients with hepatobiliary malignancies can result in substantially unfavorable outcomes. The aim of this study was to evaluate the impact of preoperative cholangitis in patients who underwent pancreaticoduodenectomy after completing neoadjuvant chemotherapy. METHODS: Participants: all adult patients (n = 449) diagnosed with pancreatic adenocarcinoma from January 1st, 2013 to March 31st, 2018 who pursued treatment at the Massachusetts General Hospital were screened. Of these 449 patients, 97 met final inclusion criteria of receiving neoadjuvant chemotherapy with intent to pursue curative surgery. Data were collected via retrospective chart review including baseline characteristics, survival, episodes of preoperative cholangitis, and surgical complications. RESULTS: In patients completing successful pancreaticoduodenectomy surgery, preoperative cholangitis is associated with increased mortality (HR 2.67, 95% CI:1.16-6.13). This finding is independent of postoperative outcomes or tumor recurrence rate. The presence of cholangitis did not impact completion of neoadjuvant chemotherapy (92% vs 85%, p = 0.5) or ability to proceed to surgery (76% vs 75%, p = 1.0). Preoperative cholangitis was not associated with postoperative morbidity (42.1% vs 45.1%, p = 1.0). CONCLUSIONS: One episode of cholangitis during neoadjuvant chemotherapy is associated with increased mortality following successful pancreaticoduodenectomy, independent of immediate postoperative outcomes or tumor recurrence. Preoperative cholangitis does not affect ability to pursue neoadjuvant chemotherapy or complete successful surgery. Patients who develop cholangitis during the neoadjuvant chemotherapy treatment phase may reflect a distinct phenotype of patients with PDAC with a complex and more challenging clinical course.

Intraductal papillary mucinous neoplasms of the pancreas with concurrent pancreatic and periampullary neoplasms.

BACKGROUND: Intraductal papillary mucinous neoplasms (IPMN) have been reported to be associated with concurrent, distinct pancreatic ductal adenocarcinoma (con-PDAC) in about 8% (range, 4-10%) of resected branch duct (BD) lesions. In addition, other pancreatic and ampullary tumors are occasionally diagnosed with IPMN in patients undergoing pancreatic surgery. The objective of this study is to describe the prevalence, clinicopathologic characteristics and prognosis of IPMN with concurrent pancreatic and ampullary neoplasms, especially con-PDAC. METHODS: The combined databases of pancreatic resections from the Massachusetts General Hospital and the Negrar Hospital, Italy, were analyzed for patients who had been diagnosed with IPMN and concurrent pancreatic or ampullary neoplasms. RESULTS: 2762 patients underwent pancreatic surgery from January 2000 to December 2012. Sixteen percent (n = 441) had pathologically confirmed IPMN and 11% of these (n = 50) had a different distinct synchronous pancreatic neoplasm. The majority of these, 62%, were con-PDAC, followed by neuroendocrine neoplasms (10%) and ampullary carcinoma (10%). Less frequently, mucinous (6%) as well as serous cystic neoplasms (6%), adenosquamous carcinoma (4%) and distal bile duct cancer (2%) were diagnosed. Among all patients with synchronous neoplasms, 66% harbored BD-IPMN, 28% combined IPMN and 6% main duct IPMN. Abdominal pain and/or jaundice were the leading symptoms in half of patients. CONCLUSION: IPMN, mainly BD-IPMN, are associated with con-PDAC in about 7% of patients and account for 62% of all concurrent pancreatic/ampullary neoplasms. Other synchronous neoplasms may be found sporadically with IPMN without a suspected association.

Follicle center lymphoma of the ampulla of Vater presenting with jaundice: report of a case.

We report the case of a 56-year-old woman who presented with biliary obstruction due to a neoplasm involving the duodenum in the area of the ampulla of Vater and the head of the pancreas. Clinically and radiographically, she was thought to have pancreatic carcinoma. Histologic examination of the specimen from a Whipple procedure revealed malignant lymphoma, follicle center type, follicular, grade 1 of 3 (follicular, predominantly small cleaved cell type), arising in the duodenum and invading the pancreas. Five peripancreatic lymph nodes were partially involved by lymphoma. Follicle center lymphoma presenting as a mass involving the ampulla of Vater with jaundice has not been described previously. Our case indicates that this type of lymphoma can occur in this location and can present with features that mimic pancreatic carcinoma.

Peritoneal exfoliative cytology and Ki-ras mutational analysis in patients with pancreatic adenocarcinoma.

This is the first description of the detection of pancreatic adenocarcinoma peritoneal metastasis by established radiolabeled polymerase chain reaction (PCR) based Ki-ras mutational analysis. The present study evaluates both routine cytology and Ki-ras mutational analysis in the detection of peritoneal micrometastases in 24 subjects with pancreatic adenocarcinoma compared to seven control cases of chronic pancreatitis and seven control cases of cholecystitis. Locoregional extension, vascular invasion, and distal metastases were confirmed in 21/24 (88%) of the subjects with pancreatic adenocarcinoma by compute tomography, angiography, endosonography, or laparoscopy. The most common site of histologically confirmed extrapancreatic involvement was the vasculature (29%), followed by the liver (25%), duodenum (17%), peritoneum (17%), and lymph nodes (12%). Peritoneal lavage cytology was positive in 3/24 (12%) cases of pancreatic carcinoma while Ki-ras codon 12 mutational analysis was positive in 2/24 (8%). Two histologically confirmed cases of peritoneal metastases were not detected by either methodology, while peritoneal lavage cytology detected malignant cells in one case with histologically confirmed lymph node metastasis.

Mixed gonadal dysgenesis: clinical, cytogenetic, endocrinological, and histopathological findings in 16 patients.

We describe clinical, cytogenetic, endocrine, and histopathological findings in 16 patients with mixed gonadal dysgenesis (MGD). All patients except 1 presented genital ambiguity and 10 of them had Ullrich-Turner manifestations. The 45,X/46,XY karyotype was the most frequent with a predominance of 45,X cells in both peripheral lymphocytes and gonads. In all cases Müllerian and Wolffian remnants and/or derivatives were found and in some patients both Wolffian- and Müllerian-derived structures were identified on the streak or testicular side. Postpubertal patients exhibited variable degrees of virilization and all of them had hypergonadotropism coexisting with low to normal baseline serum levels of testosterone; their testicular response to human chorionic gonadotropin (HCG) in terms of testosterone secretion was also variable, ranging from minimal to almost a normal response. All prepubertal patients but 1 had normal baseline levels of pituitary gonadotropins and testosterone and their gonadal response to the HCG challenge was highly variable. With the exception of 1 case, who had a 45,X/46,XY(p-) karyotype, no correlation between the cytogenetic data and degree of external genital ambiguity and the hormonal findings was observed. Additional information on the specific structural abnormalities involving the testis-determining gene of the Y chromosome in patients with MGD is needed in order to further understand the mechanisms responsible for the wide variability characteristic of this disorder.

Interstitial protease activation is the central event in progression to necrotizing pancreatitis.

BACKGROUND: Although intracellular protease activation is thought to be an early event in acute pancreatitis, factors determining progression from edematous to necrotizing pancreatitis are largely unknown. With enterokinase as a probe and an immunoassay quantifying free trypsinogen activation peptides (TAP), we sought evidence for the presence of interstitial trypsinogen in edematous pancreatitis and documented the effects of its ectopic activation. METHODS: Edematous pancreatitis in the rat was induced by supramaximal stimulation with cerulein (5 micrograms/kg/hr) and coupled with enterokinase infused into the pancreatic duct at 30 mm Hg. Blue dextran infusion at this pressure corroborated interstitial delivery. Rats with no stimulation, maximal physiologic stimulation (0.25 microgram/kg/hr of cerulein), or intraductal saline infusion served as controls. TAP levels measured by enzyme-linked immunosorbent assay, 6-hour survival, and histopathology were used as end points. RESULTS: Intraductal enterokinase infusion alone or in combination with maximal physiologic stimulation generated only slight increases in TAP level and no or minimal pancreatic injury. In contrast, enterokinase superimposed on edematous pancreatitis (supramaximal cerulein stimulation) produced fulminant pancreatitis and rapid death of all animals within 6 hours. Pancreatic histopathology showed severe intrapancreatic hemorrhage, acinar inflammation, and necrosis. TAP levels were significantly higher in plasma (p = 0.02), urine (p = 0.05), and ascites (p < 0.001) when compared with all other groups. CONCLUSIONS: In edematous pancreatitis a large pool of trypsinogen accumulates in the interstitial space. Activation of these proenzymes leads to catastrophic consequences and may underlie progression from mild to necrotizing pancreatitis.

Evidence for extraluminal trypsinogen activation in three different models of acute pancreatitis.

BACKGROUND: Inappropriate extraluminal activation of trypsin is assumed to play a part in the pathogenesis of acute pancreatitis (AP), but proof has been elusive because active trypsin is transient and difficult to measure. We have previously shown increased levels of trypsinogen activation peptides (TAP), a direct measure of trypsin activation, to correlate with severity of AP, tissue necrosis, and survival in a rodent model induced by cerulein hyperstimulation and bile salt infusion. The present study seeks to show that increased trypsinogen activation also characterizes three other models of experimental AP in rodents to give credence to the generality of the phenomenon and to its potential relevance to human AP. METHODS: Experimental AP was induced in mice by a choline-deficient diet supplemented with ethionine and in rats by creation of a closed duodenal loop or by ligation of the biliopancreatic duct plus physiologic stimulation. TAP were quantified by an immunoassay in tissue and plasma at various time points after onset of AP. RESULTS: In the group with choline-deficient diet supplemented with ethionine a significant increase in tissue and plasma TAP was found at 48 and 72 hours, respectively. In the group with closed duodenal loop significant TAP elevations were found in plasma as early as 6 hours and in the group with ligation of the biliopancreatic duct plus physiologic stimulation at 24 hours. CONCLUSIONS: These experiments provide further evidence that extraluminal protease activation is a pathophysiologic event common to the evolution of various models of experimental acute pancreatitis and therefore increase the likelihood that this phenomenon is important in the human disease as well.

Linkage of oxidative and nonoxidative ethanol metabolism in the pancreas and toxicity of nonoxidative ethanol metabolites for pancreatic acinar cells.

BACKGROUND: Alcohol abuse is a major cause of pancreatic damage. Recent experimental evidence suggests that fatty acid ethyl esters (FAEE), nonoxidative ethanol metabolites, injure pancreatic acinar cells. Linkage between oxidative and nonoxidative metabolism of ethanol in the pancreas may contribute to increased FAEE levels. METHODS: To study the association between oxidative and nonoxidative ethanol metabolism, FAEE concentration and FAEE synthase activity in rat pancreatic and liver homogenates incubated with ethanol were evaluated with and without inhibitors of oxidative ethanol metabolism. For toxicity studies, trypsinogen activation peptide synthesis as a measure of pancreatic cell injury was quantitated in unstimulated and cerulein-stimulated isolated pancreatic acinar cells incubated with ethanol or FAEE. RESULTS: Inhibition of oxidative ethanol metabolism results in a 2- to 3-fold increase in nonoxidative ethanol metabolism to FAEE in pancreas and in liver. Both ethanol and FAEE induce increased intracellular trypsinogen activation by more than 50% in the presence of physiologic concentrations of cerulein in vitro. CONCLUSIONS: These findings demonstrate that the inhibition of oxidative ethanol metabolism results in an increase in flux through the nonoxidative pathway and support the proposition that alcohol-induced pancreatic injury is mediated at least in part by FAEE, which are important products of pancreatic ethanol metabolism.

A rat model of pancreatic ductal adenocarcinoma: targeting chemical carcinogens.

BACKGROUND: Current experimental models of pancreatic cancer either fail to reproduce the ductal phenotype or cause simultaneous cancers in other organs also. To develop an animal of pancreatic cancer that accurately mimics the human condition, we restricted carcinogenic exposure to the pancreas and specifically targeted ductal epithelial cells. Three different carcinogens were either implanted directly into the pancreas or infused into the pancreatic duct, with or without near-total pancreatectomy (as a means of inducing pancreatic ductal cell proliferation). METHODS: Groups of male Sprague-Dawley rats were exposed to varying doses of dimethylbenzanthracine (DMBA), methynitronitrosoguanidine, or ethylnitronitrosoguanidine either through direct implantation into the pancreas or infusion into the pancreatic duct. Near-total pancreatectomy was added in all groups except two DMBA implantation groups. Surviving rats were killed at 3, 6, 9, or 12 months, and the pancreata were evaluated histologically. RESULTS: All three carcinogens caused pancreatic inflammation, ductal hyperplasia, atypia, and dysplasia beginning by 3 months and becoming more prominent at later time points. Only DMBA caused frequent invasive pancreatic ductal adenocarcinoma, which was first evident by 6 months. The prevalence of pancreatic cancer among DMBA-treated rats evaluated after 10 months was 39% (19 of 49). The addition of pancreatic resection did not enhance pancreatic cancer development. CONCLUSIONS: Of the strategies tested, only direct implantation of DMBA into the rat pancreas frequently produces pancreatic cancer histologically similar to human ductal adenocarcinoma. The development of hyperplastic, atypical, and dysplastic changes preceding and accompanying carcinomas suggests that these lesions are preneoplastic. This model recapitulates the progression from normal to neoplastic epithelium and is likely to be useful for the study of morphologic and molecular mechanisms underlying the early stages of pancreatic carcinogenesis and for the investigation of novel diagnostic and therapeutic techniques.

Differing roles of nitric oxide in the pathogenesis of acute edematous versus necrotizing pancreatitis.

BACKGROUND: Microcirculatory changes and leukocyte-endothelial interaction are both central to the pathogenesis of acute pancreatitis. We studied the effects of nitric oxide (NO) donors (intravenous or inhaled) and NO inhibitors, which affect each of these processes, on markers of experimental mild (edematous) and severe (necrotizing) pancreatitis in rats. METHODS: Mild pancreatitis was induced with intravenous cerulein (n = 100) and severe pancreatitis with intravenous cerulein and intraductal glycodeoxycholic acid (n = 100). Each group was randomly divided into five equal treatment subgroups: control, NO-synthase substrate L-arginine, NO donor sodium nitroprusside, NO-synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME), and NO-inhalation. After 6 hours edema was measured by a wet/dry weight ratio, and pancreatic injury was quantified by tissue levels of trypsinogen activation peptides (TAPs) and by histologic analysis of inflammation and necrosis. RESULTS: In mild pancreatitis (1) both NO donors reduced edema formation (p < 0.001) and also reduced intrapancreatic TAPs (p < 0.03); (2) L-NAME significantly increased tissue TAPs (p < 0.03); and (3) inhaled NO had no effect. In severe pancreatitis (1) both intravenous NO donors reduced edema formation (p < 0.005) and both markedly reduced intrapancreatic TAPs (p < 0.001); (2) L-NAME did not further increase the already high tissue TAPs; and (3) inhaled NO decreased tissue TAPs (p = 0.01). Evaluation of inflammation and necrosis by histologic scoring confirmed the reduction of pancreatic injury by NO donors and worsening with NO-synthase inhibitor. CONCLUSIONS: NO donors have a beneficial effect on edema formation in acute pancreatitis but confer more important protection against ectopic trypsinogen activation, which correlates with mortality, inflammation, and necrosis. Although direct microcirculatory action is likely, the salutary effect of inhaled NO in severe pancreatitis may suggest indirect action on circulating leukocytes, which are thought to potentiate tissue injury.

Regional effects of nafamostat, a novel potent protease and complement inhibitor, on severe necrotizing pancreatitis.

BACKGROUND: We evaluated the effect of the novel protease inhibitor nafamostat on rat necrotizing pancreatitis through different routes of administration. METHODS: Three hours after the induction of severe pancreatitis, the rats received intravenous gabexate or intravenous or local mesenteric intra-arterial nafamostat. At 9 hours, ascites and bronchoalveolar lavage fluid were collected for the evaluation of capillary leakage (Evans blue extravasation). Pancreas and lung were excised for histologic features, myeloperoxidase, and trypsinogen activation peptide. Twenty-four hour survival was evaluated. RESULTS: Only the intravenous infusion of nafamostat significantly reduced myeloperoxidase (11.7 +/- 2.3 vs 18.3 +/- 1.8 mU/mg; P <.05) and capillary leakage in lungs (Evans blue dye, 1.6 +/- 0.3 vs 2.6 +/- 0.3; P <.05). Only intra-arterial infusion of nafamostat significantly diminished capillary peritoneal leakage (Evans blue dye, 3.6 +/- 0.9 vs 9.4 +/- 0.4; P <.01). Typsinogen activation peptide levels were significantly reduced in all groups, but only intra-arterial infusion did so to baseline. Histologic inflammation in the pancreas was most significantly reduced after intra-arterial infusion (0.92 +/- 0.08 vs 2.91 +/- 0.06; P <.05). No form of protease inhibition reduced mortality rates. CONCLUSIONS: The effects of protease inhibition depend on the route of administration. Nafamostat has maximal effects on the pancreas and peritoneal capillary leakage when delivered by way of local intra-arterial infusion, and shows a greater reduction of lung leukocyte infiltration and capillary leakage by the intravenous route. Nafamostat is more effective than gabexate.

Biological implications of tumor cells in blood and bone marrow of pancreatic cancer patients.

BACKGROUND: Patients with pancreatic cancer often have tumor recurrence despite curative resection. Cancer cells detected in blood or bone marrow at the time of diagnosis may relate to tumor stage and to prognosis. Recent research emphasis has centered on tumor cells in bone marrow aspirates, but whether these represent early micrometastases or blood-borne cells in transit is unknown. PATIENTS AND METHODS: We developed a specific immunocytochemical assay that evaluated more than 5.3 x 10(6) extracted mononuclear cells per sample of blood and bone marrow and that could identify a single tumor cell in that population. The assay was applied to samples of blood and bone marrow from 105 patients with pancreatic cancer and 66 controls. The prevalence of isolated tumor cells was compared with Union Internationale Contre le Cancer (UICC) stage. A multivariate Cox regression analysis for survival was performed. RESULTS: Pancreatic cancer cells were detected in 26% of blood samples and in 24% of bone marrow specimens. Specificity for cancer was 96%. The prevalence of isolated tumor cells in patients with proven resectable cancer was 9% in blood and 13% in bone marrow. The prevalence increased with UICC tumor stage in blood (P =.04) but not in bone marrow (P =.52) and correlated in blood with resectability (P =.02), progression of disease (P=.08), and peritoneal dissemination (P =.003). While survival correlated significantly with tumor stage (P <.001) and isolated tumor cells in blood correlated with tumor stage, the finding of cancer cells in blood or bone marrow, or both, was not independently associated with survival in patients with pancreatic cancer. CONCLUSIONS: Isolated tumor cells in blood but not bone marrow reflect the stage of growth and spread of pancreatic cancer, particularly in the peritoneal cavity. The findings are consistent with cells in bone marrow aspirates being in transit, not implanted. These disseminated cancer cells may be the consequence, rather than the cause, of progression.

Analysis of K-ras oncogene mutations in chronic pancreatitis with ductal hyperplasia.

BACKGROUND: K-ras oncogene mutations have been identified in up to 95% of pancreatic cancers, implying their critical role in their molecular pathogenesis. However, the earliest stage in which K-ras mutations can be detected in potential precursor lesions of pancreatic cancer remains unclear. This study evaluates pancreatic ductal hyperplasia in the setting of chronic pancreatitis, which predisposes to pancreatic cancer development, for K-ras codon 12 and 13 mutations. METHODS: Paraffin-embedded surgical specimens from 42 patients with chronic pancreatitis were examined microscopically for the presence of ductal hyperplasia. Both hyperplastic and nonhyperplastic ducts were microdissected from the specimens that contained hyperplasia (11 of 42). Four of the remaining specimens without hyperplasia served as controls. Genomic DNA was extracted, and polymerase chain reaction and amplification of the K-ras oncogene was performed. Polymerase chain reaction products were evaluated by means of hybridization to mutant specific oligonucleotide probes and by means of automated DNA sequencing. RESULTS: K-ras codon 12 mutations representing glycine to valine substitutions were present in 2 of (18%) 11 patients with ductal hyperplasia. No mutations were found in the controls without ductal hyperplasia. CONCLUSIONS: Our study supports the premise that K-ras mutations develop in a subset of chronic pancreatitis associated hyperplasia and provides a genetic basis for the potential progression of chronic pancreatitis to pancreatic cancer.