Ex vivo human pancreatic slice preparations offer a valuable model for studying pancreatic exocrine biology

Abstract

A genuine understanding of human exocrine pancreas biology and pathobiology has been hampered by a lack of suitable preparations and reliance on rodent models employing dispersed acini preparations. We have developed an organotypic slice preparation of the normal portions of human pancreas obtained from cancer resections. The preparation was assessed for physiologic and pathologic responses to the cholinergic agonist carbachol (Cch) and cholecystokinin (CCK-8), including 1) amylase secretion, 2) exocytosis, 3) intracellular Ca responses, 4) cytoplasmic autophagic vacuole formation, and 5) protease activation. Cch and CCK-8 both dose-dependently stimulated secretory responses from human pancreas slices similar to those previously observed in dispersed rodent acini. Confocal microscopy imaging showed that these responses were accounted for by efficient apical exocytosis at physiologic doses of both agonists and by apical blockade and redirection of exocytosis to the basolateral plasma membrane at supramaximal doses. The secretory responses and exocytotic events evoked by CCK-8 were mediated by CCK-A and not CCK-B receptors. Physiologic agonist doses evoked oscillatory Ca increases across the acini. Supraphysiologic doses induced formation of cytoplasmic autophagic vacuoles and activation of proteases (trypsin, chymotrypsin). Maximal atropine pretreatment that completely blocked all the Cch-evoked responses did not affect any of the CCK-8-evoked responses, indicating that rather than acting on the nerves within the pancreas slice, CCK cellular actions directly affected human acinar cells. Human pancreas slices represent excellent preparations to examine pancreatic cell biology and pathobiology and could help screen for potential treatments for human pancreatitis.

Calcium signalling in the acinar environment of the exocrine pancreas: physiology and pathophysiology

“…; Liang et al . ). A limited amount of work on acinar cell Ca 2+ signalling in pancreatic segments has confirmed that the basic character of such signals, as established in isolated cell studies, is also valid in the intact pancreas (Ashby et al .…”

“…Physiological, short-lasting and repetitive local Ca 2+ signals control acinar fluid and enzyme secretion (Petersen, 1992;, whereas sustained global elevations of the cytosolic Ca 2+ concentration ([Ca 2+ ] i ), elicited by pathological agents, play a key role in the development of the acinar cell damage and death leading to acute pancreatitis (AP) (Gerasimenko et al 2014). Most of the work on PAC Ca 2+ signalling has been carried out on isolated mouse cells, but the key results have been confirmed in studies on isolated human PACs (Murphy et al 2008;Liang et al 2017). A limited amount of work on acinar cell Ca 2+ signalling in pancreatic segments has confirmed that the basic character of such signals, as established in isolated cell studies, is also valid in the intact pancreas (Ashby et al 2003).…”

Endocrine-exocrine signaling drives obesity-associated pancreatic ductal adenocarcinoma

“…Evidence supports a direct effect of CCK on CCK receptor signaling in rodent acinar cells. Although CCK receptor expression in human acinar cells is lower than observed in rodents, recent work supports a similar direct effect by physiologic and supraphysiologic concentrations of CCK on intracellular signaling and zymogen release in primary human acinar cells (Liang et al, 2017;Murphy et al, 2008). Alternatively, CCK has been shown to stimulate insulin secretion from beta cells (Lo et al, 2011), which in turn could modulate early tumorigenesis.…”

Islet–immune interactions in type 1 diabetes: the nexus of beta cell destruction

“…Responses to well characterized stimuli for the secretion of hormones [e.g. insulin (glucose, KCl) and glucagon (KCl, arginine)] and enzymes [amylase, lipase and trypsinogen (CCK-8, carbachol)] [117] can be assessed in real time under steady state conditions, and the experimental system can likely be modulated with the addition of inflammatory cytokines or other soluble factors to mimic or mollify the T1D microenvironment. The potential drawbacks of this platform include the confounding influence of pancreatic enzymes, as well as lack of innervation and blood flow limiting tissue thickness to limit hypoxia-induced stress.…”