MicroRNAs targeting oncogenes are down-regulated in pancreatic malignant transformation from benign tumors

BACKGROUND MicroRNA (miRNA) expression profiles have been described in pancreatic ductal adenocarcinoma (PDAC), but these have not been compared with pre-malignant pancreatic tumors. We wished to compare the miRNA expression signatures in pancreatic benign cystic tumors (BCT) of low and high malignant potential with PDAC, in order to identify miRNAs deregulated during PDAC development. The mechanistic consequences of miRNA dysregulation were further evaluated. METHODS Tissue samples were obtained at a tertiary pancreatic unit from individuals with BCT and PDAC. MiRNA profiling was performed using a custom microarray and results were validated using RT-qPCR prior to evaluation of miRNA targets. RESULTS Widespread miRNA down-regulation was observed in PDAC compared to low malignant potential BCT. We show that amongst those miRNAs down-regulated, miR-16, miR-126 and let-7d regulate known PDAC oncogenes (targeting BCL2, CRK and KRAS respectively). Notably, miR-126 also directly targets the KRAS transcript at a "seedless" binding site within its 3'UTR. In clinical specimens, miR-126 was strongly down-regulated in PDAC tissues, with an associated elevation in KRAS and CRK proteins. Furthermore, miR-21, a known oncogenic miRNA in pancreatic and other cancers, was not elevated in PDAC compared to serous microcystic adenoma (SMCA), but in both groups it was up-regulated compared to normal pancreas, implicating early up-regulation during malignant change. CONCLUSIONS Expression profiling revealed 21 miRNAs down-regulated in PDAC compared to SMCA, the most benign lesion that rarely progresses to invasive carcinoma. It appears that miR-21 up-regulation is an early event in the transformation from normal pancreatic tissue. MiRNA expression has the potential to distinguish PDAC from normal pancreas and BCT. Mechanistically the down-regulation of miR-16, miR-126 and let-7d promotes PDAC transformation by post-transcriptional up-regulation of crucial PDAC oncogenes. We show that miR-126 is able to directly target KRAS; re-expression has the potential as a therapeutic strategy against PDAC and other KRAS-driven cancers

Η αιμοδυναμική φαρμακινητική μελέτη της Fenoldopam σε ασθενείς με κίρρωση του ύπατος

In the present study the haemodynamic and pharmacodynamic effects, as well as the pharmacokynetics of fenoldopam, a selective agonist of the postsynaptic dopaminergic receptors were studied, in patients with liver cirrhosis. A pilot study of intravenously administered fenoldopam was initially carried out in 5 patients, in increasing doses od 0,05 to 1,6 μg /kg/min. On the basis of the results, the dose to be used in the haemodynamic study (0,05, 0,5, 1 and 1,6 μg/kg.min) was defined, each infusion lasting for 30 minutes. In this study the haemodynamic effect of fenoldpam was assessed, on the systematic and splanchic haemodynamic parameters, in 12 patients with cirrhosis and portal hypertention (in 6 with compensated and 6 with decompensated liver disease). Finally, a pharmacokinetic asseaament of fenoldopam was carried out, in another 12 patients with compensated cirrhosis. In these patients fenoldopam was given either per os (50 mg) or interavenously (0,5 μg/kg/min for 2 hours) in a radom order in two different days at least one week apart. Intravenous fenoldopam administration resulted in dose dependent reduction in blood pressure and reduction of the systemic Vascular resistance with concomitant increase in cardiac output. The portial pressure was significantly increased due to increase in portial blod flow, as a result of splanchnic atrerial vasodilation. All the haemodynamic parametrs were rapidly returned to baseline, 30 minutes after stopping the drug infusion.ABSTRACT TRUNCATE

Complete resolution of acute pancreatitis-induced chylous ascites following transhepatic portal vein stenting

We introduce a case of a 73-year-old man who developed intractable chylous ascites due to portal vein compression as a result of peripancreatic inflammatory changes after acute biliary pancreatitis. After stenting the portal vein stenosis, the chylous ascites improved from requiring weekly paracentesis to requiring no drainage within 4 months of the procedure and at the 15-month follow-up. To our knowledge, it is the first case reported in the literature where portal vein stenting has successfully been used to treat pancreatitis-induced chylous ascites.</jats:p

Splanchnic and systemic haemodynamic response to volume changes in patients with cirrhosis and portal hypertension

We investigated the haemodynamic response to volume depletion and subsequent repletion in patients with cirrhosis and portal hypertension. Twelve patients with compensated cirrhosis and portal hypertension were included in the study. The haemodynamic changes occurring after removal of approx. 15% of the blood volume, and subsequently after isovolume repletion with colloid, were assessed. Baseline haemodynamic measurements showed increased cardiac output and a systemic vascular resistance at the lower limit of normal. The hepatic venous pressure gradient (HVPG) was increased, at 18 mmHg. After depletion, arterial pressure, cardiac output and all right-heart-sided pressures decreased, and systemic vascular resistance increased. HVPG decreased to 16.0 mmHg. All the above changes were statistically significant. After blood volume restitution, the haemodynamic values returned to baseline. In particular, an increase in HVPG was shown in four out of the twelve patients (two with ascites and two without), which was small in three of them. However, HVPG remained the same as or lower than the baseline in the other eight patients. Patients with cirrhosis and portal hypertension exhibit an abnormal haemodynamic response to blood volume depletion. After volume repletion, no increase in the portal pressure was noted in this group of patients as a whole, although four out of the twelve patients did show an increase, possibly due to extensive collateral circulation.</jats:p

Pancreatic Cysts: Diagnostic Role of EUS-Guided Microforceps Biopsy and Confocal Laser Endomicroscopy

Frequent use of high-quality cross-sectional imaging has led to a significant rise in diagnosis of pancreatic cystic lesions (PCLs). Despite the fact that enormous effort has been put into the research of PCLs within the last two decades and multiple guidelines have been developed, our clinical decision-making especially in regard to mucinous lesions remains limited. Currently, clinical assessment, cross-sectional imaging and EUS with fluid analysis (if appropriate) belong to the standard care in patients with PCLs. For differentiation of mucinous from nonmucinous cysts, the sensitivity of cytological investigation and CEA in the cyst fluid is 42% and 52-79%, respectively. Due to the limited accuracy, further diagnostic tools are warranted. Two EUS-guided approaches have been introduced recently. Through-the-(19-gauge EUS) needle Moray microforceps have been developed, and several studies have acknowledged their contribution to the correct diagnosis as they help to overcome limited cellularity of the EUS-guided cyst fluid aspiration and traditional cytology. Confocal laser endomicroscopy offers real-time images and seems to be a promising method for the diagnosis and differential diagnosis of pancreatic PCLs. Example images of the needle-based confocal laser endomicroscopy criteria for the diagnosis of PCLs have been suggested recently. Before both, Moray microforceps and confocal laser endomicroscopy can be widely accepted, further studies are necessary to determine the real diagnostic yield and the clinical efficacy.</jats:p