Computed high-b-value high-resolution DWI improves solid lesion detection in IPMN of the pancreas.

OBJECTIVES: To examine the effect of high-b-value computed diffusion-weighted imaging (cDWI) on solid lesion detection and classification in pancreatic intraductal papillary mucinous neoplasm (IPMN), using endoscopic ultrasound (EUS) and histopathology as a standard of reference. METHODS: Eighty-two patients with known or suspected IPMN were retrospectively enrolled. Computed high-b-value images at b = 1000 s/mm2 were calculated from standard (b = 0, 50, 300, and 600 s/mm2) DWI images for conventional full field-of-view (fFOV, 3 × 3 × 4 mm3 voxel size) DWI. A subset of 39 patients received additional high-resolution reduced-field-of-view (rFOV, 2.5 × 2.5 × 3 mm3 voxel size) DWI. In this cohort, rFOV cDWI was compared against fFOV cDWI additionally. Two experienced radiologists evaluated (Likert scale 1-4) image quality (overall image quality, lesion detection and delineation, fluid suppression within the lesion). In addition, quantitative image parameters (apparent signal-to-noise ratio (aSNR), apparent contrast-to-noise ratio (aCNR), contrast ratio (CR)) were assessed. Diagnostic confidence regarding the presence/absence of diffusion-restricted solid nodules was assessed in an additional reader study. RESULTS: High-b-value cDWI at b = 1000 s/mm2 outperformed acquired DWI at b = 600 s/mm2 regarding lesion detection, fluid suppression, aCNR, CR, and lesion classification (p = < .001-.002). Comparing cDWI from fFOV and rFOV revealed higher image quality in high-resolution rFOV-DWI compared to conventional fFOV-DWI (p ≤ .001-.018). High-b-value cDWI images were rated non-inferior to directly acquired high-b-value DWI images (p = .095-.655). CONCLUSIONS: High-b-value cDWI may improve the detection and classification of solid lesions in IPMN. Combining high-resolution imaging and high-b-value cDWI may further increase diagnostic precision. CLINICAL RELEVANCE STATEMENT: This study shows the potential of computed high-resolution high-sensitivity diffusion-weighted magnetic resonance imaging for solid lesion detection in pancreatic intraductal papillary mucinous neoplasia (IPMN). The technique may enable early cancer detection in patients under surveillance. KEY POINTS: • Computed high-b-value diffusion-weighted imaging (cDWI) may improve the detection and classification of intraductal papillary mucinous neoplasms (IPMN) of the pancreas. • cDWI calculated from high-resolution imaging increases diagnostic precision compared to cDWI calculated from conventional-resolution imaging. • cDWI has the potential to strengthen the role of MRI for screening and surveillance of IPMN, particularly in view of the rising incidence of IPMNs combined with now more conservative therapeutic approaches.

Treatment characteristics and outcomes of pure Acinar cell carcinoma of the pancreas - A multicentric European study on radically resected patients.

BACKGROUND: Acinar cell carcinomas (ACC) belong to the exocrine pancreatic malignancies. Due to their rarity, there is no consensus regarding treatment strategies for resectable ACC. METHODS: This is a retrospective multicentric study of radically resected pure pancreatic ACC. Primary endpoints were overall survival (OS) and disease-free survival (DFS). Further endpoints were oncologic outcomes related to tumor stage and therapeutic protocols. RESULTS: 59 patients (44 men) with a median age of 64 years were included. The median tumor size was 45.0 mm. 61.0% were pT3 (n = 36), nodal positivity rate was 37.3% (n = 22), and synchronous distant metastases were present in 10.1% of the patients (n = 6). 5-Years OS was 60.9% and median DFS 30 months. 24 out of 31 recurred systemically (n = 18 only systemic, n = 6 local and systemic). Regarding TNM-staging, only the N2-stage negatively influenced OS and DFS (p = 0.004, p = 0.001). Adjuvant treatment protocols (performed in 62.7%) did neither improve OS (p = 0.542) nor DFS (p = 0.159). In 9 cases, radical resection was achieved following neoadjuvant therapy. DISCUSSION: Radical surgery is currently the mainstay for resectable ACC, even for limited metastatic disease. Novel (neo)adjuvant treatment strategies are needed, since current systemic therapies do not result in a clear survival benefit in the perioperative setting.

Secreted factors from mouse embryonic fibroblasts maintain repopulating function of single cultured hematopoietic stem cells.

Hematopoietic stem cell self-renewal, proliferation, and differentiation are independently regulated by intrinsic as well as extrinsic mechanisms. We previously demonstrated that murine proliferation of hematopoietic stem cells is supported in serum-free medium supplemented with two growth factors, stem cell factor and interleukin 11. The survival of hematopoietic stem cells is additionally improved by supplementing this medium with two more growth factors, neural growth factor and collagen 1 (four growth factors) or serum-free medium conditioned by the hematopoietic stem cell-supportive stromal UG26-1B6 cells1. Here, we describe a robust and versatile alternative source of conditioned medium from mouse embryonic fibroblasts. We found that this conditioned medium supports survival and phenotypical identity of hematopoietic stem cells, as well as cell cycle entry in single cell cultures of CD34- CD48- CD150+ Lineage- SCA1+ KIT+ cells supplemented with two growth factors. Strikingly, in comparison with cultures in serum-free medium with four growth factors, conditioned medium from mouse embryonic fibroblasts increases the numbers of proliferating clones and the number of Lineage- SCA1+ KIT+ cells, both with two and four growth factors. In addition, conditioned medium from mouse embryonic fibroblasts supports self-renewal in culture of cells with short- and long-term hematopoiesis-repopulating ability in vivo. These findings identify conditioned medium from mouse embryonic fibroblasts as a robust alternative serumfree source of factors to maintain self-renewal of in vivo-repopulating hematopoetic stem cells in culture.

Loss of P53 Function Activates JAK2-STAT3 Signaling to Promote Pancreatic Tumor Growth, Stroma Modification, and Gemcitabine Resistance in Mice and Is Associated With Patient Survival.

BACKGROUND & AIMS: One treatment strategy for pancreatic ductal adenocarcinoma is to modify, rather than deplete, the tumor stroma. Constitutive activation of the signal transducer and activator of transcription 3 (STAT3) is associated with progression of pancreatic and other solid tumors. We investigated whether loss of P53 function contributes to persistent activation of STAT3 and modification of the pancreatic tumor stroma in patients and mice. METHODS: Stat3, Il6st (encodes gp130), or Trp53 were disrupted, or a mutant form of P53 (P53R172H) or transgenic sgp130 were expressed, in mice that developed pancreatic tumors resulting from expression of activated KRAS (KrasG12D, KC mice). Pancreata were collected and analyzed by immunohistochemistry, in situ hybridization, quantitative reverse-transcription polymerase chain reaction (qPCR), or immunoblot assays; fluorescence-activated cell sorting was performed to identify immune cells. We obtained frozen pancreatic tumor specimens from patients and measured levels of phosphorylated STAT3 and P53 by immunohistochemistry; protein levels were associated with survival using Kaplan-Meier analyses. We measured levels of STAT3, P53, ligands for gp130, interleukin 6, cytokines, sonic hedgehog signaling, STAT3 phosphorylation (activation), and accumulation of reactive oxygen species in primary pancreatic cells from mice. Mice with pancreatic tumors were given gemcitabine and a Janus kinase 2 (JAK2) inhibitor; tumor growth was monitored by 3-dimensional ultrasound. RESULTS: STAT3 was phosphorylated constitutively in pancreatic tumor cells from KC mice with loss or mutation of P53. Tumor cells of these mice accumulated reactive oxygen species and had lower activity of the phosphatase SHP2 and prolonged phosphorylation of JAK2 compared with tumors from KC mice with functional P53. These processes did not require the gp130 receptor. Genetic disruption of Stat3 in mice, or pharmacologic inhibitors of JAK2 or STAT3 activation, reduced fibrosis and the numbers of pancreatic stellate cells in the tumor stroma and altered the types of immune cells that infiltrated tumors. Mice given a combination of gemcitabine and a JAK2 inhibitor formed smaller tumors and survived longer than mice given control agents; the tumor stroma had fewer activated pancreatic stellate cells, lower levels of periostin, and alterations in collagen production and organization. Phosphorylation of STAT3 correlated with P53 mutation and features of infiltrating immune cells in human pancreatic tumors. Patients whose tumors had lower levels of phosphorylated STAT3 and functional P53 had significantly longer survival times than patients with high levels of phosphorylated STAT3 and P53 mutation. CONCLUSIONS: In pancreatic tumors of mice, loss of P53 function activates JAK2-STAT3 signaling, which promotes modification of the tumor stroma and tumor growth and resistance to gemcitabine. In human pancreatic tumors, STAT3 phosphorylation correlated with P53 mutation and patient survival time. Inhibitors of this pathway slow tumor growth and stroma formation, alter immune cell infiltration, and prolong survival of mice. Transcript profiling: ArrayExpress accession number: E-MTAB-3278.

Neural influences on human intestinal epithelium in vitro.

KEY POINTS: We present the first systematic and, up to now, most comprehensive evaluation of the basic features of epithelial functions, such as basal and nerve-evoked secretion, as well as tissue resistance, in over 2200 surgical specimens of human small and large intestine. We found no evidence for impaired nerve-evoked epithelial secretion or tissue resistance with age or disease pathologies (stomach, pancreas or colon cancer, polyps, diverticulitis, stoma reversal). This indicates the validity of future studies on epithelial secretion or resistance that are based on data from a variety of surgical specimens. ACh mainly mediated nerve-evoked and basal secretion in the small intestine, whereas vasoactive intestinal peptide and nitric oxide were the primary pro-secretory transmitters in the large intestine. The results of the present study revealed novel insights into regional differences in nerve-mediated secretion in the human intestine and comprise the basis by which to more specifically target impaired epithelial functions in the diseased gut. ABSTRACT: Knowledge on basic features of epithelial functions in the human intestine is scarce. We used Ussing chamber techniques to record basal tissue resistance (R-basal) and short circuit currents (ISC; secretion) under basal conditions (ISC-basal) and after electrical field stimulation (ISC-EFS) of nerves in 2221 resectates from 435 patients. ISC-EFS was TTX-sensitive and of comparable magnitude in the small and large intestine. ISC-EFS or R-basal were not influenced by the patients' age, sex or disease pathologies (cancer, polyps, diverticulitis). Ion substitution, bumetanide or adenylate cyclase inhibition studies suggested that ISC-EFS depended on epithelial cAMP-driven chloride and bicarbonate secretion but not on amiloride-sensitive sodium absorption. Although atropine-sensitive cholinergic components prevailed for ISC-EFS of the duodenum, jejunum and ileum, PG97-269-sensitive [vasoactive intestinal peptide (VIP) receptor 1 antagonist] VIPergic together with L-NAME-sensitive nitrergic components dominated the ISC-EFS in colonic preparations. Differences in numbers of cholinergic or VIPergic neurons, sensitivity of epithelial muscarinic or VIP receptors, or stimulus frequency-dependent transmitter release were not responsible for the region-specific transmitter contribution to ISC-EFS. Instead, the low atropine-sensitivity of ISC-EFS in the colon was the result of high cholinesterase activity because neostigmine revealed cholinergic components. Colonic ISC-EFS remained unchanged after tachykinin, P2X, P2Y or A1 and A2 receptor blockade. R-basal was smaller and ISC-basal was higher in the small intestine. TTX and bumetanide decreased ISC-basal in all regions, suggesting nerve-dependent secretory tone. ISC-basal was atropine-sensitive in the small intestine and PG97-269-sensitive in the large intestine. This comprehensive study reveals novel insights into region-specific nerve-mediated secretion in the human small and large intestine.

KRT81 and HNF1A expression in pancreatic ductal adenocarcinoma: investigation of predictive and prognostic value of immunohistochemistry-based subtyping.

Even after decades of research, pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal disease and responses to conventional treatments remain mostly poor. Subclassification of PDAC into distinct biological subtypes has been proposed by various groups to further improve patient outcome and reduce unnecessary side effects. Recently, an immunohistochemistry (IHC)-based subtyping method using cytokeratin-81 (KRT81) and hepatocyte nuclear factor 1A (HNF1A) could recapitulate some of the previously established molecular subtyping methods, while providing significant prognostic and, to a limited degree, also predictive information. We refined the KRT81/HNF1A subtyping method to classify PDAC into three distinct biological subtypes. The prognostic value of the IHC-based method was investigated in two primary resected cohorts, which include 269 and 286 patients, respectively. In the second cohort, we also assessed the predictive effect for response to erlotinib + gemcitabine. In both PDAC cohorts, the new HNF1A-positive subtype was associated with the best survival, the KRT81-positive subtype with the worst, and the double-negative with an intermediate survival (p < 0.001 and p < 0.001, respectively) in univariate and multivariate analyses. In the second cohort (CONKO-005), the IHC-based subtype was additionally found to have a potential predictive value for the erlotinib-based treatment effect. The revised IHC-based subtyping using KRT81 and HNF1A has prognostic significance for PDAC patients and may be of value in predicting treatment response to specific therapeutic agents.

Pancreatic neuropathy and neuropathic pain--a comprehensive pathomorphological study of 546 cases.

BACKGROUND & AIMS: Chronic pancreatitis (CP) and pancreatic adenocarcinoma (PCa) are characterized by intrapancreatic neural alterations and pain. Our aims were to: (a) Investigate whether neuropathic changes like pancreatic neuritis, increased neural density, and hypertrophy are phenomena only in CP or whether they are also evident in other pancreatic disorders as well, (b) study possible variations in neural cancer cell invasion among malignant pancreatic tumors, and (c) explore whether these neuropathic changes contribute to pain sensation. METHODS: Neuropathic changes were studied in PCa (n=149), in CP (n=141), in pancreatic tumors (PTm) including serous/mucinous cystadenomas, invasive/noninvasive intraductal papillary mucinous neoplasias, benign/malignant neuroendocrine tumors, ampullary cancers (n=196), and in normal pancreas (n=60). The results were correlated with GAP-43 expression, tissue inflammation, pancreatic neuritis, neural invasion, fibrosis, desmoplasia, pain, and patient survival. RESULTS: Increased neural density and hypertrophy were only detected in PCa and CP and were strongly associated with GAP-43 over expression and abdominal pain. The severity of pancreatic neuritis was strongest in PCa and was closely linked to changes in neural density and hypertrophy. The aggressiveness of neural cancer cell invasion was most prominent in PCa and was related to neuropathic changes, desmoplasia, and pain. Severe and enduring pain were strongly associated with poor prognosis in PCa patients. CONCLUSIONS: Enhanced neural density and hypertrophy are only typical features of CP and PCa among all investigated pancreatic disorders. Such neuropathic changes, including damage to nerves by inflammatory and/or cancer cells, seem to enhance and generate pancreatic neuropathic pain.

Pancreatic pain.

Abdominal pain is an important clinical symptom in pancreatic diseases. There is increasing evidence that pain in chronic pancreatitis and pancreatic cancer is triggered by pancreatic neuropathy. Damage to intrapancreatic nerves seems to support the maintenance and exacerbation of neuropathic pain. In chronic pancreatitis, intrapancreatic nerves are invaded by immune cells. This observation led to the hypothesis that neuro-immune interactions play a role in the pathogenesis of chronic pancreatitis and the accompanying abdominal pain syndrome. Similarly, pancreatic cancer cells infiltrate the perineurium of local nerves, which may in part explain the severe pain experienced by the patients. Furthermore, perineural invasion extending into extrapancreatic nerves may preclude curative resection and thus often leads to local recurrence. In recent years, the involvement of a variety of neurotrophins and neuropeptides in the pathogenesis of pancreatic pain was discovered. This review summarises recent data on the mechanisms of neuropathy and pain generation in pancreatic disorders.

Calcium Imaging of Nerve-Mast Cell Signaling in the Human Intestine.

Introduction: It is suggested that an altered microenvironment in the gut wall alters communication along a mast cell nerve axis. We aimed to record for the first time signaling between mast cells and neurons in intact human submucous preparations. Methods: We used the Ca2+ sensitive dye Fluo-4 AM to simultaneously image changes in intracellular calcium [Ca+2]i (%ΔF/F) in neurons and mast cells. Data are presented as median with interquartile ranges (25/75%). Results: We recorded nerve responses in 29 samples upon selective activation of 223 mast cells by IgE receptor cross linking with the antibody mAb22E7. Mast cells responded to mAb22E7 with a median [Ca+2]i increase of 20% (11/39) peaking 90 s (64/144) after the application. Only very few neurons responded and the median percentage of responding neuronal area was 0% (0/5.9). Mast cell activation remained in the presence of the fast sodium channel blocker tetrodotoxin. Specific neuronal activation by transmural electrical field stimulation (EFS) in 34 samples evoked instantaneously [Ca+2]i signals in submucous neurons. This was followed by a [Ca+2]i peak response of 8%ΔF/F (4/15) in 33% of 168 mast cells in the field of view. The mast cell response was abolished by the nerve blocker tetrododoxin, reduced by the Calcitonin Gene-Related Peptide receptor 1 antagonist BIBN-4096 and the Vasoactive Intestinal Peptide receptor antagonist PG97-269, but not by blockade of the neurokinin receptors 1-3. Conclusion: The findings revealed bidirectional signaling between mast cells and submucous neurons in human gut. In our macroscopically normal preparations a nerve to mast cell signaling was very prominent whereas a mast cell to nerve signaling was rather rare.

A Novel Grading System Based on Tumor Budding and Cell Nest Size Is a Strong Predictor of Patient Outcome in Esophageal Squamous Cell Carcinoma.

The determination of prognosis in patients with esophageal squamous cell carcinoma (ESCC) is primarily based on staging according to the TNM-classification, whereas conventional grading is of minor clinical importance because of its deficiencies in prognostic patient stratification. Recently, a novel, highly prognostic grading scheme based on budding activity and cell nest size has been proposed for squamous cell carcinoma (SCC) of both pulmonary as well as oral origin. In order to investigate the utility and transferability of this approach to ESCC, we evaluated budding activity and cell nest size, as well as other histomorphologic characteristics, in a cohort of 135 primarily resected tumors and correlated the results with clinicopathologic and outcome parameters. High budding activity and small cell nest size showed a strong association with reduced overall, disease-specific, and disease-free survival (P<0.001, respectively) in ESCC. The combination of both markers in a 3-step grading system showed excellent prognostic separation of well-differentiated (G1), moderately differentiated (G2), and poorly differentiated (G3) carcinomas (P<0.001). The hazard ratio for disease-free survival in multivariate analysis under inclusion of stage was 2.97 for G2 and 5.42 for G3 ESCC (P<0.001). World Health Organization-based grading had no prognostic impact. Taken together, our data prove the value of tumor budding and cell nest size as excellent outcome predictors in ESCC and validate the utility of a previously established grading scheme proposed for oral and pulmonary SCC in this tumor entity. Ultimately, these combined efforts may result in a universal grading system for SCC regardless of the site of origin.

Anti-Hu antibodies activate enteric and sensory neurons.

IgG of type 1 anti-neuronal nuclear antibody (ANNA-1, anti-Hu) specificity is a serological marker of paraneoplastic neurological autoimmunity (including enteric/autonomic) usually related to small-cell lung carcinoma. We show here that IgG isolated from such sera and also affinity-purified anti-HuD label enteric neurons and cause an immediate spike discharge in enteric and visceral sensory neurons. Both labelling and activation of enteric neurons was prevented by preincubation with the HuD antigen. Activation of enteric neurons was inhibited by the nicotinic receptor antagonists hexamethonium and dihydro-ß-erythroidine and reduced by the P2X antagonist pyridoxal phosphate-6-azo (benzene-2,4-disulfonic acid (PPADS) but not by the 5-HT3 antagonist tropisetron or the N-type Ca-channel blocker ω-Conotoxin GVIA. Ca++ imaging experiments confirmed activation of enteric neurons but not enteric glia. These findings demonstrate a direct excitatory action of ANNA-1, in particular anti-HuD, on visceral sensory and enteric neurons, which involves nicotinic and P2X receptors. The results provide evidence for a novel link between nerve activation and symptom generation in patients with antibody-mediated gut dysfunction.

Mechanical stress activates neurites and somata of myenteric neurons.

The particular location of myenteric neurons, sandwiched between the 2 muscle layers of the gut, implies that their somata and neurites undergo mechanical stress during gastrointestinal motility. Existence of mechanosensitive enteric neurons (MEN) is undoubted but many of their basic features remain to be studied. In this study, we used ultra-fast neuroimaging to record activity of primary cultured myenteric neurons of guinea pig and human intestine after von Frey hair evoked deformation of neurites and somata. Independent component analysis was applied to reconstruct neuronal morphology and follow neuronal signals. Of the cultured neurons 45% (114 out of 256, 30 guinea pigs) responded to neurite probing with a burst spike frequency of 13.4 Hz. Action potentials generated at the stimulation site invaded the soma and other neurites. Mechanosensitive sites were expressed across large areas of neurites. Many mechanosensitive neurites appeared to have afferent and efferent functions as those that responded to deformation also conducted spikes coming from the soma. Mechanosensitive neurites were also activated by nicotine application. This supported the concept of multifunctional MEN. 14% of the neurons (13 out of 96, 18 guinea pigs) responded to soma deformation with burst spike discharge of 17.9 Hz. Firing of MEN adapted rapidly (RAMEN), slowly (SAMEN), or ultra-slowly (USAMEN). The majority of MEN showed SAMEN behavior although significantly more RAMEN occurred after neurite probing. Cultured myenteric neurons from human intestine had similar properties. Compared to MEN, dorsal root ganglion neurons were activated by neurite but not by soma deformation with slow adaptation of firing. We demonstrated that MEN exhibit specific features very likely reflecting adaptation to their specialized functions in the gut.

Activity of protease-activated receptors in primary cultured human myenteric neurons.

Activity of the four known protease-activated receptors (PARs) has been well studied in rodent enteric nervous system and results in animal models established an important role for neuronal PAR2. We recently demonstrated that, unlike in rodents, PAR1 is the dominant neuronal protease receptor in the human submucous plexus. With this study we investigated whether this also applies to the human myenteric plexus. We used voltage sensitive dye recordings to detect action potential discharge in primary cultures of human myenteric neurons in response to PAR activating peptides (APs). Application of the PAR1-AP (TFLLR) or PAR4-AP (GYPGQV) evoked spike discharge in 79 or 23% of myenteric neurons, respectively. The PAR1-AP response was mimicked by the endogenous PAR1 activator thrombin and blocked by the PAR1 antagonists SCH79797. Human myenteric neurons did not respond to PAR2-AP. This was not due to culture conditions because all three PAR-APs evoked action potentials in cultured guinea pig myenteric neurons. Consecutive application of PAR-APs revealed coexpression (relative to the population responding to PAR-APs) of PAR1/PAR2 in 51%, PAR1/PAR4 in 43%, and of PAR2/PAR4 in 29% of guinea pig myenteric neurons. Our study provided further evidence for the prominent role of neuronal PAR1 in the human enteric nervous system.