Jens Standop

5-Lipoxygenase and Leukotriene B4 Receptor Are Expressed in Human Pancreatic Cancers But Not in Pancreatic Ducts in Normal Tissue

The 5-lipoxygenase (5-LOX) pathway is critical for pancreatic cancer cell growth and escape from apoptosis. Inhibition of 5-LOX blocks proliferation and induces apoptosis in human pancreatic cancer cells. However, the expression of 5-LOX and its downstream signaling pathway have not been investigated in human pancreatic adenocarcinoma. Reverse transcriptase-polymerase chain reaction revealed expression of 5-LOX mRNA in all pancreatic cancer cell lines tested including, PANC-1, AsPC-1, and MiaPaCa2 cells, but not in normal pancreatic ductal cells. The expression of 5-LOX protein in pancreatic cancer cell lines was demonstrated by Western blotting. Finally, 5-LOX up-regulation in human pancreatic cancer tissues was verified by intense positive staining in cancer cells by immunohistochemistry. Staining for the 5-LOX protein was particularly evident in the ductal components of the more differentiated tumors but not in ductal cells in normal pancreatic tissues from cadaver donors. Immunohistochemistry also revealed strong staining of cancer tissues with an antibody to the receptor of the downstream 5-LOX metabolite, leukotriene B(4). The current study demonstrated marked expression of 5-LOX and the leukotriene B(4) receptor in human pancreatic cancer tissues. These findings provide further evidence of up-regulation of this pathway in pancreatic cancer and that LOX inhibitors are likely to be valuable in the treatment of this dreadful disease.

Early diagnosis of pancreatic cancer: neutrophil gelatinase-associated lipocalin as a marker of pancreatic intraepithelial neoplasia.

Pancreatic cancer is a highly lethal malignancy with a dismal 5-year survival of less than 5%. The scarcity of early biomarkers has considerably hindered our ability to launch preventive measures for this malignancy in a timely manner. Neutrophil gelatinase-associated lipocalin (NGAL), a 24-kDa glycoprotein, was reported to be upregulated nearly 27-fold in pancreatic cancer cells compared to normal ductal cells in a microarray analysis. Given the need for biomarkers in the early diagnosis of pancreatic cancer, we investigated the expression of NGAL in tissues with the objective of examining if NGAL immunostaining could be used to identify foci of pancreatic intraepithelial neoplasia, premalignant lesions preceding invasive cancer. To examine a possible correlation between NGAL expression and the degree of differentiation, we also analysed NGAL levels in pancreatic cancer cell lines with varying grades of differentiation. Although NGAL expression was strongly upregulated in pancreatic cancer, and moderately in pancreatitis, only a weak expression could be detected in the healthy pancreas. The average composite score for adenocarcinoma (4.26±2.44) was significantly higher than that for the normal pancreas (1.0) or pancreatitis (1.0) (P<0.0001). Further, although both well- and moderately differentiated pancreatic cancer were positive for NGAL, poorly differentiated adenocarcinoma was uniformly negative. Importantly, NGAL expression was detected as early as the PanIN-1 stage, suggesting that it could be a marker of the earliest premalignant changes in the pancreas. Further, we examined NGAL levels in serum samples. Serum NGAL levels were above the cutoff for healthy individuals in 94% of pancreatic cancer and 62.5% each of acute and chronic pancreatitis samples. However, the difference between NGAL levels in pancreatitis and pancreatic cancer was not significant. A ROC curve analysis revealed that ELISA for NGAL is fairly accurate in distinguishing pancreatic cancer from non-cancer cases (area under curve=0.75). In conclusion, NGAL is highly expressed in early dysplastic lesions in the pancreas, suggesting a possible role as an early diagnostic marker for pancreatic cancer. Further, serum NGAL measurement could be investigated as a possible biomarker in pancreatitis and pancreatic adenocarcinoma.

Expression of Nerve Growth Factors in Pancreatic Neural Tissue and Pancreatic Cancer

One of the characteristics of pancreatic cancer is its tendency to invade neural tissue. We hypothesized that the affinity of cancer cells for nerve tissue is related to the presence of growth factors in neural tissue and their receptors in cancer cells. Sections of pancreatic cancer and normal pancreatic tissue were examined by immunohistochemistry for the expression of the neurotrophins NGF, BDNF, NT-3, NT-4, and their receptors TrkA, TrkB, and TrkC, as well as the low-affinity receptor, p75NTR. TrkA expression was found in duct, islet, and cancer cells; TrkB was found in the α-cells of the islet only. The anti-pan-Trk antibody (TrkB3), which is presumed to recognize all three receptors, immunoreacted with duct and acinar cells in normal tissue and with cancer cells. The staining with TrkC was similar to that of TrkA. The low-affinity receptor p75NTR was expressed in the neural tissue and in scattered duct cells of the normal tissue only. Duct and acinar cells, as well as neural tissue and cancer cells, showed weak to strong immunoreactivity with NGF. NT-3 expression was noted in capillary endothelia and erythrocytes. NT-4 showed specific staining for ductule cells. The expression and distribution of neurotrophins and their receptors suggest their role in the potential of pancreatic cancer cells for neural invasion.

Gastrointestinal symptoms under opioid therapy: A prospective comparison of oral sustained-release hydromorphone, transdermal fentanyl, and transdermal buprenorphine

Introduction: The purpose of this trial was to evaluate the effect of long‐term treatment with oral sustained‐release hydromorphone, transdermal fentanyl, and transdermal buprenorphine on nausea, emesis and constipation.

Effects of hypertonic saline on myocardial blood flow in a porcine model of prolonged cardiac arrest

OBJECTIVE To evaluate the effects of hypertonic saline (HS) on myocardial reperfusion pressure (MPP) and blood flow (MBF), and cardiac index (CI) during and after cardiopulmonary resuscitation (CPR). METHODS In 21 domestic swine (16-23 kg) open chest cardiac massage was initiated after 10 min of ventricular fibrillation. With the onset of CPR animals randomly received HS (7.2%; 2 ml/kg per 10 min or 4 ml/kg per 20 min) or normal saline ((NS); 2 ml/kg per 10 min). Haemodynamic variables were monitored continuously, and coloured microspheres were used to measure MBF and CI before cardiac arrest (CA), during CPR and 5, 30 and 120 min after the return of spontaneous circulation. RESULTS During CPR HS significantly increased MPP, MBF, and CI in comparison to NS (P<0.05, resp., MANOVA). Doubling the volume of HS did not improve the haemodynamic effects seen after application of 2 ml/kg per 10 min. HS-infusion significantly increased the survival rate at 120 min, 6/7 and 5/7 animals receiving 2 ml/kg per 10 min or 4 ml/kg per 20 min versus 2/7 after NS-infusion (P<0.05, chi(2)-test). CONCLUSIONS HS applied during open chest cardiac massage enhanced MBF and CI, and significantly increased resuscitation success and survival rate. The positive effects of this promising new approach need to be confirmed in clinical studies.

Pancreatic Cell Lines: A Review

Pancreatic cancer has an extremely poor prognosis and lacks early diagnostic and therapeutic possibilities, mainly because of its silent course and explosive fatal outcome. The histogenesis of the disease and early biochemical and genetic alterations surrounding carcinogenesis are still controversial. In vitro studies offer a useful tool to study physiologic, pathophysiologic, differentiation, and transformation processes of cells and to understand some of these shortcomings. The extreme difficulties in isolating individual pancreatic cells and their purification by maintaining their native characteristics have limited research in this area. This review is intended to present and discuss the current availability of rodent and pancreatic cell lines, their differences as well as the difficulties, limitations, and characteristics of these cultured cells. Discussed are in vitro models; ductal, islet, and acinar cell culture; cell differentiation; cell transformation, including genetic and chromosomal alterations; as well as tumor cell markers. Also addressed are the advantages and problems associated with the cell culture in humans and rodents. Advancements in tissue culture technique and molecular biology offer steady progress in this important line of research. The improved methods not only promise the establishment of &bgr;-cell cultures for the treatment of diabetes, but also for studying sequential genetic alterations during pancreatic carcinogenesis and in understanding the tumor cell origin.

Operative Re-intervention Following Pancreatic Head Resection: Indications and Outcome

BackgroundThis study analyzed indication and outcome regarding operative re-intervention following pancreatoduodenectomy (PD) and pancreatogastrostomy (PG) with special emphasis on complications related to redo surgery.Patients and MethodsTwo hundred eighty-five patients who underwent PD with PG between 1989 and 2008 were identified from a pancreatic resection database and indications for repeat surgery were registered. Patients with and without reoperation were analyzed with regard to gender, age, underlying disease, length of hospital stay, mortality rate, and postoperative complications.ResultsThirty-one patients (11%) underwent operative reintervention. Early intra-abdominal extraluminal postoperative bleeding was the main cause for redo surgery followed by abdominal abscesses. Thirteen percent of patients with and 1.9% without secondary surgery died during the postoperative course. Forty-five percent of reoperated patients had to undergo at least one more operation resulting in doubling of the length of hospital stay. There was no correlation between patients’ gender, age, and underlying disease and the need for operative reintervention. However, redo surgery was associated with higher incidence of delayed gastric emptying, pancreatic fistula and bleeding, and non-surgery related complication. Intra-abdominal bleeding and abscesses, insufficiencies of bilio-digestive and gut anastomosis, wound infections, and pancreatitis were observed significantly more often in patients with secondary surgery.ConclusionsComplications after pancreatic resection that require operative re-intervention are associated with a notably increased mortality, ranging between 13% and 60%. Apart from the surgeon’s experience in selecting patients and his/her personal technical skills in performing a pancreaticoduodenectomy, timely anticipation and determined management of postoperative complications is essential for improving the outcome of this operation.

The combination of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) and Genistein is effective in inhibiting pancreatic cancer growth.

Objectives: Our previous studies have shown that, contrary to many other human pancreatic adenocarcinoma cell lines, AsPC1 cells are resistant to the apoptotic effect of the tumor necrosis factor-related apoptosis-inducing ligand, also called Apo2L (TRAIL/Apo2L). In our in vitro studies, the combination of TRAIL/Apo2L and protein synthesis inhibitor, genistein, but not genistein alone, was, however, effective in inducing apoptosis in AsPC1 cells. In the present study, we examined the effect of TRAIL/Apo2L with genistein on the growth of AsPC1 cells in vitro and in vivo. Methods: Mice with orthotopically transplanted AsPC1 cells were treated either with TRAIL/Apo2L, Genistein (Gen) or a combination of both (TRAIL/Apo2L + Gen) for 14 days. After 14 days, the size and weight of the tumors were registered and the apoptosis of the tumor cells were determined by the TUNEL method. In vitro, the effect of combination treatment on cytotoxicity was assessed by MTT assay and apoptosis was assessed by DAPI staining. FADD, caspase 3, and PARP proteins were determined by Western blot. Results: No toxic side effects were observed in either group. The tumor volume was significantly smaller and the apoptotic ratio was higher in the TRAIL + Gen group than in the other 2 groups. The apoptotic effect was associated with the caspase-3 activation. Z-VAD-FMK partially inhibited apoptosis by TRAIL + Gen. Conclusions: These results indicate that the combination of TRAIL/Apo2L with genistein presents a promising therapeutic approach for the treatment of pancreatic cancer. Further detail investigations are needed, however, to verify the mechanisms of this combination therapy.

Species Differences in the Distribution of Drug-Metabolizing Enzymes in the Pancreas

We investigated the cellular expression of 9 cytochrome P450-isozymes (CYP1A1, CYP1A2, CYP2B6, CYP2C8,9,19, CYP2D1, CYP2E1, CYP3A1, CYP3A2, CYP3A4) and 3 glutathione S-transferase-isozymes (GST-π , GST-α, GST-μ ) in the pancreas of hamsters, mice, rats, rabbits, pigs, dogs and monkeys, and in comparison with the human pancreas. A wide variation was found in the cellular localization of these enzymes between the 8 species. Most enzymes were expressed in the pancreas of the hamster, mouse, monkey and human, whereas rats, pigs, rabbits and dogs were lacking several isozymes. However, in all of the species the islet cells expressed more enzymes than ductal and acinar cells. An exclusive expression of enzymes in the islet cells was found in the hamster (CYP2E1), mouse (CYP1A1, CYP1A2, GST-α, GST-μ ), rat (CYP2C8,9,19), rabbit (CYP1A2, CYP2B6, GST-π), and pig (CYP1A1). Although no polymorphism was found in the pancreas of animals, in human tissue four enzymes were missing in about 50% of the cases. The results imply a greater importance of the islet cells in the metabolism of xenobiotics within the pancreas. The differences in the distribution of these drug-metabolizing enzymes in the pancreas between the species call for caution when extrapolating experimental results to humans.

Experimental Animal Models in Pancreatic Carcinogenesis: Lessons for Human Pancreatic Cancer

The silent course of pancreatic cancer and its explosive fatal outcome have hindered studies of tumor histogenesis and the identification of early biochemical and genetic alterations that could help to diagnose the disease at a curable stage and develop therapeutic strategies. Experimental animal models provide important tools to assess risk factors, as well as preventive and therapeutic possibilities. Although several pancreatic cancer models presently exist, only models that closely resemble human tumors in morphological, clinical, and biological aspects present useful media for preclinical studies. Because an estimated 70% of human tumors are induced by carcinogens and because a significant association has been found between cigarette smoking and pancreatic cancer, chemically induced models are of particular value. Moreover, in such models the etiology, modifying factors, effects of diets, and naturally occurring products can be studied and early diagnostic, preventive, and therapeutic possibilities sought out. Many of the existing models are described in this review, and the advantages and shortcomings of each model and their clinical implications are discussed.