resiniferatoxin and Pancreatitis

Neural cross talk between visceral organs may play a role in mediating inflammation and pain remote from the site of the insult. We hypothesized such a cross talk exists between the duodenum and pancreas, and further it induces pancreatitis in response to intraduodenal toxins. A dichotomous spinal innervation serving both the duodenum and pancreas was examined, and splanchnic nerve responses to mechanical stimulation of these organs were detected. This pathway was then excited on the duodenal side by exposure to ethanol followed by luminal mustard oil to activate transient receptor potential subfamily A, member 1 (TRPA1). Ninety minutes later, pancreatic inflammation was examined. Ablation of duodenal afferents by resiniferatoxin (RTX) or blocking TRPA1 by Chembridge (CHEM)-5861528 was used to further investigate the duodeno-pancreatic neural reflex via TRPA1. ~40% of dorsal root ganglia (DRG) from the spinal cord originated from both duodenum and pancreas via dichotomous peripheral branches; ~50% splanchnic nerve single units responded to mechanical stimulation of both organs. Ethanol sensitized TRPA1 currents in cultured DRG neurons. Pancreatic edema and myeloperoxidase activity significantly increased after intraduodenal ethanol followed by mustard oil (but not capsaicin) but significantly decreased after ablation of duodenal afferents by using RTX or blocking TRPA1 by CHEM-5861528. We found the existence of a neural cross talk between the duodenum and pancreas that can promote acute pancreatitis in response to intraduodenal chemicals. It also proves a previously unexamined mechanism by which alcohol can induce pancreatitis, which is novel both in terms of the site (duodenum), process (neurogenic), and receptor (TRPA1).

Topics: Acute Disease; Animals; Capsaicin; Central Nervous System Depressants; Diterpenes; Duodenum; Edema; Ethanol; Fluorescent Antibody Technique; Ganglia, Spinal; Male; Muscle Contraction; Pancreas; Pancreatitis; Patch-Clamp Techniques; Physical Stimulation; Rats; Rats, Sprague-Dawley; Reflex; Sensory Receptor Cells; Splanchnic Nerves; Stomach; TRPA1 Cation Channel; TRPC Cation Channels; TRPV Cation Channels

Endoscopic retrograde cholangiopancreatography (ERCP) has a high risk of pancreatitis although the underlying mechanisms are unclear. Transient receptor potential vanilloid 1 (TRPV1) is a cation channel expressed on C and Adelta fibres of primary sensory neurons and is activated by low pH. TRPV1 activation causes release of inflammatory mediators that produce oedema and neutrophil infiltration. We previously demonstrated that neurogenic factors contribute to the pathogenesis of pancreatitis. Resiniferatoxin (RTX) is a TRPV1 agonist that, in high doses, defunctionalises C and Adelta fibres. When we discovered that the pH of radio-opaque contrast solutions used for ERCP was 6.9, we hypothesised that low pH may contribute to the development of contrast-induced pancreatitis via activation of TRPV1.. Rats underwent equal pressure pancreatic ductal injection of contrast solutions at varying pH with or without RTX.. Contrast solution (pH 6.9) injected into the pancreatic duct caused a significant increase in pancreatic oedema, serum amylase, neutrophil infiltration, and histological damage. Solutions of pH 7.3 injected at equal pressure caused little damage. The severity of the pancreatitis was significantly increased by injection of solutions at pH 6.0. To determine if the effects of low pH were mediated by TRPV1, RTX was added to the contrast solutions. At pH levels of 6.0 and 6.9, RTX significantly reduced the severity of pancreatitis.. Contrast solutions with low pH contribute to the development of pancreatitis through a TRPV1-dependent mechanism. It is possible that increasing the pH of contrast solution and/or adding an agent that inhibits primary sensory nerve activation may reduce the risk of post-ERCP pancreatitis.

Topics: Animals; Cholangiopancreatography, Endoscopic Retrograde; Contrast Media; Diterpenes; Hydrogen-Ion Concentration; Male; Neurogenic Inflammation; Neurons, Afferent; Pancreas; Pancreatitis; Rats; Rats, Sprague-Dawley; Severity of Illness Index; TRPV Cation Channels

Success of chemotherapy and alleviation of pain are frequently less than optimal in pancreatic cancer patients, leading to increasing interest in new pharmacological substances, such as vanilloids. Our study addressed the question of whether vanilloids influence pancreatic cancer cell growth, and if vanilloids could be used for pain treatment via the vanilloid 1 receptor (VR1) in pancreatic cancer patients.. In vitro, the effect of resiniferatoxin (vanilloid analogue) on apoptosis and cell growth in pancreatic cancer cells--either alone, combined with 5-fluorouracil (5-FU), or combined with gemcitabine--was determined by annexin V staining, FACS analysis, and MTT assay, respectively. VR1 expression was evaluated on RNA and protein level by quantitative polymerase chain reaction and immunohistochemistry in human pancreatic cancer and chronic pancreatitis. Patient characteristics--especially pain levels--were registered in a prospective database and correlated with VR1 expression.. Resiniferatoxin induced apoptosis by targeting mitochondrial respiration and decreased cell growth in pancreatic cancer cells without showing synergistic effects with 5-FU or gemcitabine. Expression of VR1 was significantly upregulated in human pancreatic cancer and chronic pancreatitis. VR1 expression was related to the intensity of pain reported by cancer patients but not to the intensity of pain reported by patients with chronic pancreatitis.. Resiniferatoxin induced apoptosis in pancreatic cancer cells indicates that vanilloids may be useful in the treatment of human pancreatic cancer. Furthermore, vanilloid might be a novel and effective treatment option for neurogenic pain in patients with pancreatic cancer.

Topics: Adult; Aged; Antimetabolites, Antineoplastic; Antineoplastic Agents; Apoptosis; Cell Division; Cell Line, Tumor; Chronic Disease; Deoxycytidine; Diterpenes; Drug Synergism; Drug Therapy, Combination; Female; Fluorouracil; Gemcitabine; Humans; Immunohistochemistry; Male; Middle Aged; Mitochondria; Oxidative Stress; Pain; Pancreas; Pancreatic Neoplasms; Pancreatitis; Prospective Studies; TRPV Cation Channels