Phenotype screens of murine pancreatic cancer identify a Tgf-α-Ccl2-paxillin axis driving human-like neural invasion.

Solid cancers like pancreatic ductal adenocarcinoma (PDAC), a type of pancreatic cancer, frequently exploit nerves for rapid dissemination. This neural invasion (NI) is an independent prognostic factor in PDAC, but insufficiently modeled in genetically engineered mouse models (GEMM) of PDAC. Here, we systematically screened for human-like NI in Europe's largest repository of GEMM of PDAC, comprising 295 different genotypes. This phenotype screen uncovered 2 GEMMs of PDAC with human-like NI, which are both characterized by pancreas-specific overexpression of transforming growth factor α (TGF-α) and conditional depletion of p53. Mechanistically, cancer-cell-derived TGF-α upregulated CCL2 secretion from sensory neurons, which induced hyperphosphorylation of the cytoskeletal protein paxillin via CCR4 on cancer cells. This activated the cancer migration machinery and filopodia formation toward neurons. Disrupting CCR4 or paxillin activity limited NI and dampened tumor size and tumor innervation. In human PDAC, phospho-paxillin and TGF-α-expression constituted strong prognostic factors. Therefore, we believe that the TGF-α-CCL2-CCR4-p-paxillin axis is a clinically actionable target for constraining NI and tumor progression in PDAC.

Optimizing the Personalized Care for the Management of Rectal Cancer: A Consensus Statement.

Colorectal cancer is the third most common cancer in Turkey. The current guidelines do not provide sufficient information to cover all aspects of the management of rectal cancer. Although treatment has been standardized in terms of the basic principles of neoadjuvant, surgical, and adjuvant therapy, uncertainties in the management of rectal cancer may lead to significant differences in clinical practice. In order to clarify these uncertainties, a consensus program was constructed with the participation of the physicians from the Acibadem Mehmet Ali Aydinlar and Koç Universities. This program included the physicians from the departments of general surgery, gastroenterology, pathology, radiology, nuclear medicine, medical oncology, radiation oncology, and medical genetics. The gray zones in the management of rectal cancer were determined by reviewing the evidence-based data and current guidelines before the meeting. Topics to be discussed consisted of diagnosis, staging, surgical treatment for the primary disease, use of neoadjuvant and adjuvant treatment, management of recurrent disease, screening, follow-up, and genetic counseling. All those topics were discussed under supervision of a presenter and a chair with active participation of related physicians. The consensus text was structured by centralizing the decisions based on the existing data.

Genetic landscape of pancreatic cancer: a narrative review.

BACKGROUND AND OBJECTIVE: Pancreatic cancer is an aggressive disease with an impaired survival despite improvements in clinical management. Thus, understanding disease biology is of vital importance in order to overcome therapeutic challenges and achieve better prognosis. The purpose of this review is to outline the genetic landscape of pancreatic cancer along with its clinical implications. METHODS: We reviewed existing literature using electronic databases to outline the genetic landscape in pancreatic cancer. KEY CONTENT AND FINDINGS: This review mainly contains information on the genetic background of pancreatic cancer, mainly KRAS, CDKN2A, TP53 and SMAD4, with emphasis on the importance of understanding disease biology. CONCLUSIONS: The genetic aspects of pancreatic cancer have been well described especially with the introduction of next generation sequencing techniques. Future studies focusing on translation of these alterations in clinical application might pave the way for personalized surveillance and therapy.

Targeting the undruggable oncogenic KRAS: the dawn of hope.

KRAS mutations are the drivers of various cancers, including non-small cell lung cancer, colon cancer, and pancreatic cancer. Over the last 30 years, immense efforts have been made to inhibit KRAS mutants and oncogenic KRAS signaling using inhibitors. Recently, specific targeting of KRAS mutants with small molecules revived the hopes for successful therapies for lung, pancreatic, and colorectal cancer patients. Moreover, advances in gene editing, protein engineering, and drug delivery formulations have revolutionized cancer therapy regimens. New therapies aim to improve immune surveillance and enhance antitumor immunity by precisely targeting cancer cells harboring oncogenic KRAS. Here, we review recent KRAS-targeting strategies, their therapeutic potential, and remaining challenges to overcome. We also highlight the potential synergistic effects of various combinatorial therapies in preclinical and clinical trials.

Diabetes mellitus in intraductal papillary mucinous neoplasms: A systematic review and meta-analysis.

BACKGROUND: Our current knowledge of diabetes mellitus in intraductal papillary mucinous neoplasm is very limited and its prevalence and predictive value for malignant transformation are not clear. This study sought to systematically review the literature to define the prevalence of diabetes mellitus in intraductal papillary mucinous neoplasm and to evaluate the association of diabetes mellitus with the progression to high-grade dysplasia or invasive cancer. METHODS: A PubMed/Medline systematic search was performed to identify studies reporting data on preoperative diabetes mellitus in intraductal papillary mucinous neoplasm. Articles meeting the predefined inclusion criteria were analyzed and a meta-analysis was performed. The study was preregistered (PROSPERO ID: CRD42020153581). RESULTS: From the initially detected 827 studies, 27 studies including resected patients with histologically confirmed intraductal papillary mucinous neoplasm were included. The global prevalence of preoperative diabetes mellitus was 25% (1,112 of 4,412); whereas new-onset/worsening diabetes mellitus was reported in 6% of patients (68 of 1,202). The meta-analysis revealed that patients with pre-existing diabetes mellitus had an increased risk of harboring a main pancreatic duct involvement (risk ratio 1.43, 95% confidence interval: 1.21-1.69, P < .001), high-grade dysplasia (risk ratio 1.27, 95% confidence interval: 1.01-1.59, P = .04), and invasive cancer (risk ratio 1.61, 95% confidence interval: 1.33-1.95, P < .001). CONCLUSION: The prevalence of diabetes mellitus in intraductal papillary mucinous neoplasm is high, and diabetic patients demonstrate an increased risk of a more aggressive disease. Therefore, diabetes mellitus should be increasingly considered in the stratification of patients with intraductal papillary mucinous neoplasm. Further investigations to determine the mechanisms behind the association with progression should be carried out.

Indirect cholinergic activation slows down pancreatic cancer growth and tumor-associated inflammation.

BACKGROUND: Nerve-cancer interactions are increasingly recognized to be of paramount importance for the emergence and progression of pancreatic cancer (PCa). Here, we investigated the role of indirect cholinergic activation on PCa progression through inhibition of acetylcholinesterase (AChE) via clinically available AChE-inhibitors, i.e. physostigmine and pyridostigmine. METHODS: We applied immunohistochemistry, immunoblotting, MTT-viability, invasion, flow-cytometric-cell-cycle-assays, phospho-kinase arrays, multiplex ELISA and xenografted mice to assess the impact of AChE inhibition on PCa cell growth and invasiveness, and tumor-associated inflammation. Survival analyses were performed in a novel genetically-induced, surgically-resectable mouse model of PCa under adjuvant treatment with gemcitabine+/-physostigmine/pyridostigmine (n = 30 mice). Human PCa specimens (n = 39) were analyzed for the impact of cancer AChE expression on tumor stage and survival. RESULTS: We discovered a strong expression of AChE in cancer cells of human PCa specimens. Inhibition of this cancer-cell-intrinsic AChE via pyridostigmine and physostigmine, or administration of acetylcholine (ACh), diminished PCa cell viability and invasion in vitro and in vivo via suppression of pERK signaling, and reduced tumor-associated macrophage (TAM) infiltration and serum pro-inflammatory cytokine levels. In the novel genetically-induced, surgically-resectable PCa mouse model, adjuvant co-therapy with AChE blockers had no impact on survival. Accordingly, survival of resected PCa patients did not differ based on tumor AChE expression levels. Patients with higher-stage PCa also exhibited loss of the ACh-synthesizing enzyme, choline-acetyltransferase (ChAT), in their nerves. CONCLUSION: For future clinical trials of PCa, direct cholinergic stimulation of the muscarinic signaling, rather than indirect activation via AChE blockade, may be a more effective strategy.

Do somatostatin-analogues have the same impact on postoperative morbidity and pancreatic fistula in patients after pancreaticoduodenectomy and distal pancreatectomy? - A systematic review with meta-analysis of randomized-controlled trials.

OBJECTIVE: Postoperative pancreatic fistula/POPF is the most feared complication in pancreatic surgery. Although several systematic reviews investigated the impact of somatostatin analogues on POPF, no stratification was performed regarding type of pancreatic resection (pancreaticoduodenectomy/PD; distal pancreatectomy/DP) and different somatostatin analogues. METHODS: This study was planed according to the Preferred-Reporting-Items-for-Systematic -Review-and-Meta-Analysis/PRISMA-guidelines. After screening databases for randomized controlled trials/RCT, studies were stratified into pancreatic resection techniques and data were pooled in meta-analyses containing subgroups of octreotide, somatostatin, lanreotide, pasireotide and vapreotide. RESULTS: The meta-analysis of studies with a mixed cohort of patients after pancreatic resection revealed a protective effect of somatostatin analogues for morbidity (RR: 0.71, p < .00001) but not for mortality (RR: 1.07, = 0.78) or intra-abdominal abscesses (RR: 1.00, p = 1.00). Moreover, no effect was visible for mortality (RR: 1.57, p = .15), morbidity (RR: 0.87, p = .15) and intra-abdominal abscesses (RR: 0.92, p = .48) after PD. The meta-analysis of patients after PD revealed no impact of somatostatin analogues on POPF (RR: 0.87, p = .19) and clinically relevant POPF (RR: 0.69, p = .30). However, treatment with somatostatin analogues in the mixed cohort showed less POPF (RR: 0.60, p < .00001) and clinically relevant POPF (RR: 0.47, p = .02), which was also the case after DP (RR: 0.41, p = .03). CONCLUSION: Somatostatin analogues did not affect POPF and clinically relevant POPF after PD, but seemed to be associated with less POPF after DP. As no sufficiently powered RCT could be identified by the systematic review, further RCTs are urgently needed to investigate the effect of somatostatin analogues after DP. STUDY REGISTRATION: CRD42018099808.

Mortality and postoperative complications after different types of surgical reconstruction following pancreaticoduodenectomy-a systematic review with meta-analysis.

BACKGROUND: Pancreaticoduodenectomy/PD is a technically demanding pancreatic resection. Options of surgical reconstruction include (1) the child reconstruction defined as pancreatojejunostomy/PJ followed by hepaticojejunostomy/HJ and the gastrojejunostomy/GJ "the standard/s-Child," (2) the s-child reconstruction with an additional Braun enteroenterostomy "BE-Child," or (3) Isolated-Roux-En-Y-pancreaticojejunostomy "Iso-Roux-En-Y," in which the pancreas anastomosis is reconstructed in a separate loop after the GJ. Yet, the impact of these reconstruction methods on patients' outcome has not been sufficiently compared in a systematic manner. METHODS: A systematic review and meta-analysis were conducted according to the Preferred-Reporting-Items-for-Systematic-review-and-Meta-Analysis/PRISMA-guidelines by screening Pubmed/Medline, Scopus, Cochrane Library and Web-of-Science. Articles meeting predefined criteria were extracted and meta-analysis was performed. RESULTS: Nineteen studies were identified comparing BE-Child or Isolated-Roux-En-Y vs. s-Child. Compared to s-Child neither BE-Child (p = 0.43) nor Iso-Roux-En-Y (p = 0.94) displayed an impact on postoperative mortality, whereas BE-Child showed less postoperative complications (p = 0.02). BE-Child (p = 0.15) and Iso-Roux-En-Y (p = 0.61) did not affect postoperative pancreatic fistula/POPF in general, but BE-Child was associated with a decrease of clinically relevant POPF (p = 0.005), clinically relevant delayed gastric emptying/DGE B/C (p = 0.004), bile leaks (p = 0.01), and hospital stay (p = 0.06). BE-Child entailed also an increased operation time (p = 0.0002) with no impact on DGE A/B/C, hemorrhage, surgical site infections and pulmonary complications. CONCLUSION: BE-Child is associated with a decreased risk for postoperative complications, particularly a decreased risk for clinically relevant DGE, POPF, and bile leaks, whereas Iso-Roux-En-Y does not seem to affect the clinical course after PD. Therefore, BE seems to be a valuable surgical method to improve patients' outcome after PD.

The impact of surgically placed, intraperitoneal drainage on morbidity and mortality after pancreas resection- A systematic review & meta-analysis.

BACKGROUND: Although routinely used, the benefit of surgically placed intraperitoneal drains after pancreas resection is still under debate. To assess the true impact of intraperitoneal drains in pancreas resection, a systematic review with meta-analysis was performed. METHODS: For this, the Preferred-Reporting-Items-for-Systematic-review-and-Meta-Analysis/PRISMA-guidelines were conducted and Pubmed/Medline, Embase, Scopus and The Cochrane Library were screened for relevant studies. RESULTS: 8 retrospective and 3 prospective studies were included in the systematic review. No difference was found between patients with or without intraperitoneal drains in mortality (Risk-ratio/RR 0.74, 95%-Confidence-interval/CI: 0.47-1.18, p = 0.20), in Grade B/C-postoperative pancreatic fistulas/POPF (RR 1.31, 95%-CI: 0.74-2.32, p = 0.35), in intraabdominal abscesses (RR 0.92, 95%-CI: 0.65-1.30, p = 0.64), in surgical site infection (RR 1.20, 95%-CI: 0.85-1.70, p = 0.30), in delayed gastric emptying (RR 1.11, 95%-CI: 0.65-1.90, p = 0.71), in postoperative haemorrhages (RR 0.92 95%-CI: 0.63-1.33, p = 0.65), in reoperations (RR 1.15, 95%-CI: 0.87-1.52, p = 0.33), or in radiological reinterventions (RR 0.95, 95%-CI: 0.69-1.31, p = 0.76). The risk for overall morbidity (RR 1.16, 95%-CI: 1.04-1.29, p = 0.008), of any POPF (RR 2.15, 95%-CI: 1.52-3.04, p < 0.0001) and of readmissions (RR 1.23, 95%-CI: 1.04-1.45, p = 0.01) was increased for patients with intraperitoneal drain compared to patients without following pancreatic resection. CONCLUSION: Regarding the controversial results of the recent prospective, randomized trials this meta-analysis revealed no difference in mortality but an increased risk for postoperative morbidity, POPF and readmissions of patients with intraperitoneal drains after pancreatic resection. Therefore, the indication for intraperitoneal drains should be critically weighed in patients undergoing pancreatic resections.

Protease signaling through protease activated receptor 1 mediate nerve activation by mucosal supernatants from irritable bowel syndrome but not from ulcerative colitis patients.

BACKGROUND & AIMS: The causes of gastrointestinal complaints in irritable bowel syndrome (IBS) remain poorly understood. Altered nerve function has emerged as an important pathogenic factor as IBS mucosal biopsy supernatants consistently activate enteric and sensory neurons. We investigated the neurally active molecular components of such supernatants from patients with IBS and quiescent ulcerative colitis (UC). METHOD: Effects of supernatants from 7 healthy controls (HC), 20 IBS and 12 UC patients on human and guinea pig submucous neurons were studied with neuroimaging techniques. We identify differentially expressed proteins with proteome analysis. RESULTS: Nerve activation by IBS supernatants was prevented by the protease activated receptor 1 (PAR1) antagonist SCHE79797. UC supernatants also activated enteric neurons through protease dependent mechanisms but without PAR1 involvement. Proteome analysis of the supernatants identified 204 proteins, among them 17 proteases as differentially expressed between IBS, UC and HC. Of those the four proteases elastase 3a, chymotrypsin C, proteasome subunit type beta-2 and an unspecified isoform of complement C3 were significantly more abundant in IBS compared to HC and UC supernatants. Of eight proteases, which were upregulated in IBS, the combination of elastase 3a, cathepsin L and proteasome alpha subunit-4 showed the highest prediction accuracy of 98% to discriminate between IBS and HC groups. Elastase synergistically potentiated the effects of histamine and serotonin-the two other main neuroactive substances in the IBS supernatants. A serine protease inhibitor isolated from the probiotic Bifidobacterium longum NCC2705 (SERPINBL), known to inhibit elastase-like proteases, prevented nerve activation by IBS supernatants. CONCLUSION: Proteases in IBS and UC supernatants were responsible for nerve activation. Our data demonstrate that proteases, particularly those signalling through neuronal PAR1, are biomarker candidates for IBS, and protease profiling may be used to characterise IBS.

The influence of neural invasion on survival and tumor recurrence in pancreatic ductal adenocarcinoma - A systematic review and meta-analysis.

OBJECTIVES: To assess the impact of neural invasion/NI on overall survival/OS and tumor recurrence in pancreatic ductal adenocarcinoma/PDAC. SUMMARY BACKGROUND DATA: NI is a histopathological hallmark of PDAC. Although some studies suggested an important role for NI on OS, disease-free/DFS and progression-free survival/PFS in PDAC, there is still no consensus on the actual role of NI on survival and local recurrence in PDAC. METHODS: Pubmed, Cochrane library, Ovid and Google Scholar were screened for the terms "pancreatic ductal adenocarcinoma", "pancreatic cancer", "survival", "tumor recurrence" and "perineural invasion". The Preferred-Reporting-Items-for-Systematic-review-and-Meta-Analysis/PRISMA-guidelines were used for systematic review and meta-analysis. Articles meeting predefined criteria were critically analysed on relevance, and meta-analyses were performed by pooling univariate and multivariate hazard ratios/HR. RESULTS: A total number of 25 studies on the influence of NI on tumor recurrence, and 121 studies analysing the influence of NI on survival were identified by systematic review. The HR of the univariate (HR 1.88; 95%-CI 1.71-2.07; p < 0.00001) and multivariate meta-analysis (HR 1.68; 95%-CI 1.47-1.92; p < 0.00001) showed a major impact of NI on OS. Likewise, NI was associated with decreased DFS (HR 2.53; 95%-CI: 1.67-3.83; p = 0.0001) and PFS (HR 2.41; 95%-CI: 1.73-3.37: p < 0.00001) multivariate meta-analysis. CONCLUSIONS: Although the power of this study is limited by missing pathological procedures to assess the true incidence of NI, NI appears to be an independent prognostic factor for OS, DFS and PFS in PDAC. Therefore, NI should be increasingly considered in patient stratification and in the development of novel therapeutic algorithms.

The impact of neoadjuvant therapy on the histopathological features of pancreatic ductal adenocarcinoma - A systematic review and meta-analysis.

BACKGROUND: Due to increased rates of curative tumor resections exceeding 60% after FOLFIRINOX-treatment, neoadjuvant therapy/NTx is increasingly recognized as an effective therapy option for downstaging borderline or locally advanced pancreatic ductal adenocarcinoma/PDAC. Yet, the effects of NTx on the common histopathological features of PDAC have not been systematically analysed. Therefore, the aim of the current study was to assess the impact of NTx on relevant histopathological features of PDAC. PATIENTS AND METHODS: Biomedical databases were systematically screened for predefined searching terms related to NTx and PDAC. The Preferred-Reporting-Items-for-Systematic-review-and-Meta-Analysis/PRISMA-guidelines were used to perform a systematic review and meta-analysis. Articles meeting the predefined criteria were analysed on relevance, and a meta-analysis was performed. RESULTS: A total of 9031 studies could be identified that analysed the effect of NTx on PDAC. Only 35 studies presented comparative data on the histological features of neoadjuvantly treated vs. upfront resected PDAC patients. In meta-analyses, the beneficial effect of NTx was reflected by reduced tumor size (T1/2: RR 2.87, 95%-CI: 1.52-5.42, P=0.001, T3/4: RR 0.78, 95%-CI: 0.69-0.89, P=0.0002), lower N-Stage (N0: RR 2.14, 95%-CI: 1.85-2.46, P<0.00001, N1: RR 0.59, 95%-CI: 0.53-0.65, P<0.00001), higher R0-rates (R0: RR 1.13, 95%-CI: 1.08-1.18, P<0.00001, R1: RR 0.66, 95%-CI: 0.58-0.76, P<0.00001), less perineural invasion (Pn1: RR 0.78, 95%-CI: 0.73-0.83, P<0.00001), less lymphatic vessel invasion (RR: 0.50, 95%-CI: 0.36-0.70, P<0.0001) and fewer G3-tumors (RR 0.82, 95%-CI: 0.71-0.94, P=0.005). CONCLUSIONS: NTx in PDAC seems to exert its beneficial effect in borderline or locally advanced PDAC over genuine tumor downstaging. Thus, although at least 40% of all NTx treated patients remain unresectable even with modern NTx regimes, neoadjuvantly treated PDAC showed not only increasing resectability rates especially after FOLFIRINOX, but even reach a lower tumor stage than primarily resected PDAC.

Preoperative biliary stenting versus operation first in jaundiced patients due to malignant lesions in the pancreatic head: A meta-analysis of current literature.

BACKGROUND: Obstructive jaundice is a common presenting symptom among patients with pancreatic cancer. While benefits of preoperative biliary drainage have been suggested by previous studies, recent evidence has shown no significant improvements of preoperative biliary drainage on the postoperative outcome but rather an increase of complications. There is no clear consensus on whether to treat malignant obstructive jaundice with preoperative biliary drainage prior to operative intervention or to proceed directly to resection. Thus, our aim was to elucidate the impact of preoperative biliary drainage of obstructive jaundice due to malignant pancreatic head tumors on postoperative morbidity and mortality. METHODS: We conducted a meta-analysis in accordance with the PRISMA guidelines and carried out a systematic search of medical databases. The results were analyzed according to predefined criteria. We pooled the incidence of overall complications, wound infection, pancreatic fistula, intra-abdominal abscess, and death within the perioperative time period. RESULTS: We initially identified 1,816 studies, and 25 of these (22 retrospective studies, 3 randomized controlled trials) were finally included in the analysis with a total number of 6,214 patients. Analysis revealed an increased incidence of overall complications (odds ratio: 1.40; 95% confidence interval: 1.14-1.72; P = .002) and wound infections (odds ratio: 1.94; 95% confidence interval: 1.48-2.53; P < .00001) in patients receiving preoperative biliary drainage compared to operative intervention first. Mortality, incidence of pancreatic fistula, or intra-abdominal abscess formation were not affected by preoperative biliary drainage. CONCLUSION: Preoperative biliary drainage does not have a beneficial effect on postoperative outcome. The increase of postoperative overall complications and wound infections urges for precise indications for preoperative biliary drainage and against routine preoperative biliary decompression.

Activity of protease-activated receptors in the human submucous plexus.

BACKGROUND & AIMS: Protease-activated receptors (PARs) are expressed in the enteric nervous system. Excessive release of proteases has been reported in functional and inflammatory bowel diseases. Studies in several animal models indicate the involvement of neural PARs. We studied the actions of different PAR-activating peptides (AP) in the human submucous plexus and performed comparative studies in guinea pig submucous neurons. METHODS: We used voltage- and calcium-sensitive dye recordings to study the effects of PAR1-AP, PAR2-AP, PAR4-AP, the PAR1 activator thrombin, and the PAR2 activator tryptase on neurons and glia in human and guinea pig submucous plexus. Human preparations were derived from surgical resections. Levels of mucosal secretion evoked by PAR-APs were measured in Ussing chambers. RESULTS: PAR1-AP and thrombin evoked a prominent spike discharge and intracellular Ca(2+) concentration ([Ca](i)) transients in most human submucous neurons and glia. PAR2-AP, tryptase, and PAR4-AP caused significantly weaker responses in a minor population. In contrast, PAR2-AP evoked much stronger responses in enteric neurons and glia of guinea pigs than did PAR1-AP or PAR4-AP. PAR1-AP, but not PAR2-AP or PAR4-AP, evoked a nerve-mediated secretion in human epithelium. The PAR1 antagonist SCH79797 inhibited the PAR1-AP, and thrombin evoked responses on neurons, glia, and epithelial secretion. In the submucous layer of human intestine, but not guinea pig intestine, PAR2-AP evoked [Ca](i) signals in CD68(+) macrophages. CONCLUSIONS: In the human submucous plexus, PAR1, rather than PAR2 or PAR4, activates nerves and glia. These findings indicate that PAR1 should be the focus of future studies on neural PAR-mediated actions in the human intestine; PAR1 might be developed as a therapeutic target for gastrointestinal disorders associated with increased levels of proteases.

Pain mechanisms in chronic pancreatitis: of a master and his fire.

BACKGROUND: Unraveling the mechanisms of pain in chronic pancreatitis (CP) remains a true challenge. The rapid development of pancreatic surgery in the twentieth century, usage of advanced molecular biological techniques, and emergence of clinician-scientists have enabled the elucidation of several mechanisms that lead to the chronic, complicated neuropathic pain syndrome in CP. However, the proper analysis of pain in CP should include three main arms of mechanisms: "peripheral nociception," "peripheral/pancreatic neuropathy and neuroplasticity," and "central neuropathy and neuroplasticity." DISCUSSION: According to our current knowledge, pain in CP involves sustained sensitization of pancreatic peripheral nociceptors by neurotransmitters and neurotrophic factors following neural damage. This peripheral pancreatic neuropathy leads to intrapancreatic neuroplastic alterations that involve a profound switch in the autonomic innervation of the human pancreas via "neural remodeling." Furthermore, this neuropathy entails a hyperexcitability of spinal sensory second-order neurons, which are subject to modulation from the brainstem via descending facilitation. Finally, viscerosensory cortical areas react to this central sensitization via spatial reorganization and thus a central neuroplasticity. The present review summarizes the current findings in these arms of mechanisms and introduces a novel concept to consistently describe pain in CP as a "predominantly neuropathic," "mixed-type" pain.

Pancreatic neuropathy results in "neural remodeling" and altered pancreatic innervation in chronic pancreatitis and pancreatic cancer.

OBJECTIVES: Chronic pancreatitis (CP) and pancreatic cancer (PCa) are characterized by intrapancreatic neuropathic alterations, including increased neural density and hypertrophy, pancreatic neuritis and neural invasion (NI) by cancer cells in PCa. The aim of this study was to identify the influence of these neuropathic changes on the quality of pancreatic innervation, intrapancreatic glia, and visceral pain. METHODS: Pancreatic nerve fiber qualities were characterized by immunohistochemical visualization of various markers, including those for sympathetic (tyrosine hydroxylase, TH) and cholinergic innervation (choline acetyltransferase, ChAT), as well as the glial transcription factor, Sox10, and the neuroepithelial progenitor cell marker, Nestin, in normal pancreas (NP, n=16), CP (n=20), and PCa (n=20) patients. The neural immunoreactivity scores of these markers were correlated with the severity of intrapancreatic neuropathic changes and with abdominal pain sensation of patients. RESULTS: Pancreatic sympathetic innervation was significantly reduced in CP and PCa, whereas parasympathetic innervation did not show major changes. Nestin neuro-immunoreactivity was stronger, and Sox10-immunoreactivity was weaker in CP and PCa than in NP. Pancreatic sympathetic and cholinergic innervation was noticeably decreased in patients with severe pancreatic neuritis, NI by cancer cells, or abdominal pain. Moreover, the neural immunoreactivity for Sox10 and Nestin also varied with intrapancreatic neuropathic alterations and abdominal pain. CONCLUSIONS: The quality of intrapancreatic nerve fibers and the activation state of intrapancreatic glia in CP and PCa are strikingly different from those in normal pancreas. This novel phenomenon of "neural remodeling" shows how pancreatic neuropathic pain and "visceral neuropathy" are associated with altered pancreatic innervation in CP and PCa.