Neurogenic Amplification of Pancreatitis Pain

描述（由申请人提供）：对于胰腺发炎或癌变患者，突发性主诉是局部组织炎症、纤维化、导管狭窄、水肿和液体压力引起的疼痛。慢性炎症胰腺的内脏传入神经传递的疼痛可能变得严重和顽固，没有有效的长期治疗方案。在这次竞争性更新中提出的研究扩展了父母补助金的最初目标，其中有两个偶然发现的新颖和潜在相关的发现。发现一：我们最近未发表的研究结果表明，高脂饮食和酒精诱导胰腺细胞瞬时受体电位香草酸4（TRPV4）通道的表达增加。TRPV4通道是响应于组织损伤后局部细胞微环境中存在的条件的非选择性阳离子通道，包括脂质介质和组织水肿。一些酒精代谢物是可以激活TRPV4的脂质介质。过度的TRPV4激活引发钙的细胞内流，其引发破坏性的细胞内级联和胰腺传入神经激活。发现二：我们发现胰腺组织损伤、炎症和疼痛相关行为通过诱导内源性阿片肽甲硫氨酸脑啡肽过表达的基因治疗显著减少。我们提出了新的研究，使用大鼠慢性胰腺炎模型和克隆胰腺细胞来进一步研究组织损伤诱导的细胞微环境的显着变化，这些变化与慢性疼痛发展过程中诱导型TRPV 4表达和激活反应相关。假设：酒精诱导的胰腺细胞损伤增加TRPV4的表达和活化，而甲硫氨酸脑啡肽保护作用降低TRPV4的表达和活化目的1确定酒精损伤对胰腺中TRPV4表达和活化的影响。目的2确定甲硫氨酸脑啡肽是否降低酒精诱导的TRPV4表达和激活。我们的总体目标是发现影响慢性疼痛的局部细胞微环境相互作用，并为慢性炎症性内脏痛的未来临床治疗提供进展。TRPV4在组织损伤后在局部反应性细胞中诱导的影响以及TRPV4在慢性疼痛中的作用尚未得到充分研究。该研究结果将为TRPV4相关的甲硫氨酸脑啡肽的镇痛、保护和修复作用提供知识。在体外用TRPV4激活剂攻击胰腺细胞的预期结果是TRPV4表达和激活应答将增加，除了在存在甲硫氨酸脑啡肽的情况下。此外，TRPV4抑制剂和甲硫氨酸脑啡肽将减少慢性胰腺炎大鼠模型中的疼痛相关行为。这些发现将扩展对局部微环境中TRPV4介导的事件的理解，这些事件在从急性到慢性内脏痛的过渡期间影响外周和中枢致敏。研究向慢性疼痛的转变是NIH蓝图和NINDS的一项使命。 公共卫生相关性：我们认为，酒精和其他相关的有害物质存在于炎症胰腺增加表达和激活的阳离子通道蛋白，瞬时受体蛋白香草酸4（TRPV4）。我们建议进行研究以证实这一初步发现，并确定内源性阿片肽甲硫氨酸脑啡肽是否可以干扰酒精损伤诱导的TRPV4表达和激活的破坏性作用。我们的新发现对改善胰腺炎和胰腺癌患者的胰腺功能和减轻疼痛具有重要意义。

DESCRIPTION (provided by applicant): For patients with inflamed or cancerous pancreas, the precipitating complaint is pain generated by local tissue inflammation, fibrosis, ductal stenosis, edema, and fluid pressure. The pain relayed by visceral afferent nerves from chronically inflamed pancreas can become severe and intractable with no effective long-term treatment options. The studies proposed in this competitive renewal extend the original aims of the parent grant with two serendipitously discovered novel and potentially related findings. Discovery #1: Our recent unpublished findings indicate that high fat diet and alcohol induce increased expression of transient receptor potential vanilloid 4 (TRPV4) channels on pancreas cells. TRPV4 channels are non-selective cation channels responsive to conditions present in the local cellular microenvironment after tissue injury, including lipid mediators and tissue edema. Some alcohol metabolites are lipid mediators that can activate TRPV4. Excessive TRPV4 activation initiates cellular influx of calcium that initiates damaging intracellular cascades and pancreas afferent nerve activation. Discovery #2: We found that pancreatic tissue damage, inflammation, and pain-related behaviors are significantly reduced by gene therapy inducing overexpression of the endogenous opioid peptide, met- enkephalin. We propose new studies using a chronic pancreatitis model in rats and clonal pancreatic cells to further investigate significant tissue injury-induced changes in the cell microenvironment that are relevant to inducible TRPV4 expression and activation responses during the development of chronic pain. Hypothesis: Alcohol-induced injury in pancreas cells increases TRPV4 expression and activation which are reduced by met-enkephalin protection Aim 1 Determine the effects of alcohol injury on TRPV4 expression and activation in the pancreas. Aim 2 Determine if alcohol-induced TRPV4 expression and activation is reduced by met-enkephalin. Our overall goal is to discover local cellular microenvironment interactions that impact chronic pain and that provide inroads for development of future clinical treatments for chronic inflammatory visceral pain. The impact of TRPV4 induced in local reactive cells after tissue damage and the role of TRPV4 in chronic pain have not been well studied. The findings will provide knowledge about analgesic, protective and reparative effects of met-enkephalin related to TRPV4. Expected outcomes of challenging pancreatic cells in vitro with TRPV4 activators are that TRPV4 expression and activation responses will increase, except in the presence of met- enkephalin. Further, TRPV4 inhibitors and met-enkephalin will reduce pain-related behaviors in the rat model of chronic pancreatitis. The findings will extend understanding of TRPV4 mediated events in the local microenvironment that impact both peripheral and central sensitization during the transition from acute to chronic visceral pain. Study of the transition to chronic pain is a mission of the NIH Blueprint and NINDS. PUBLIC HEALTH RELEVANCE: We propose that alcohol and other related injurious agents present in the inflamed pancreas increase expression and activation of the cation channel protein, transient receptor protein vanilloid 4 (TRPV4). We propose studies to confirm this preliminary finding and to determine if the endogenous opioid peptide met-enkephalin can interfere with the destructive actions induced by alcohol injury on TRPV4 expression and activation. Our novel findings have implications for improved pancreatic function and reduction of pain for patients with pancreatitis and pancreatic cancer.