Cells in focusPancreatic acinar cell: Its role in acute pancreatitis
Introduction
The pancreas has two distinct functional portions: the exocrine and the endocrine pancreas. The endocrine pancreas, consisting of pancreatic islet cells that produce insulin, glucagon, somatostatin, and pancreatic polypeptide serves to maintain the body's glucose homeostasis. The exocrine pancreas is structurally analogous to a bunch of grapes; this architecture contains microscopic, blind-ended tubules that are surrounded by polygonal acinar cells and these tubules are organized into lobules called acini. The primary function of the acini is to synthesize and secrete hydrolytic enzymes which empty into the duodenum for the digestion of our daily foodstuff. Each acinus consists of a small cluster of secretory epithelial cells that form a small central lumen, called intercellular canaliculi. Each acinar cell has a round pyramid-like shape. The acinar cell is highly polarized with two plasma membrane domains. The basolateral membrane is large and located at the acinar periphery; the apical membrane (less than 10% of total surface area of the cell) faces the acinar lumen that connects with a tiny intercalated duct. The digestive enzymes are stored in secretory granules which are concentrated near the apical membrane of the cell. The acini drain into the intercalated ducts, and groups of the intercalated ducts converge into larger intralobular ducts, which in turn drain into much larger extralobular ducts; the latter form a main collecting duct which empties into the duodenum (see Fig. 1). However, the accuracy of the traditional acinar structural model of strictly independent acini has been called into question. There are light and electron microscopy findings, suggesting that the exocrine pancreas may not be organized into true acinar units. Instead, the arrangement may consist of a complexly curving and branching system of tubules which anastomose between adjacent acini (Bockman, 1980).
Section snippets
Cell origin and plasticity
Early in the fifth week of intrauterine life in humans, the pancreas arises from the abdominal foregut as dorsal and ventral diverticular buds. The ventral bud rotates to fuse with the dorsal bud which ultimately forms the splenic portion, i.e. body and tail. The ventral duct fuses with the distal portion of the dorsal duct to form the head or duodenal portion of the pancreas.
Some studies have suggested that there is a common pancreatic progenitor which gives rise to both exocrine (acinar) and
Functions
The major function of pancreatic acinar cells is to synthesize, store and secrete digestive enzymes so as to catalyze the hydrolysis of food constituents into absorbable forms. Pancreatic acinar cells secrete three major categories of digestive enzymes; they are α-amylase, lipase and proteases which are responsible for the hydrolysis of carbohydrates, fats and proteins, respectively. The synthesis of the digestive enzymes begins at the ribosomes located in the cytosol of the cell. To enable
Associated pathologies
The clinical disorders associated with pancreatic acinar cell dysfunction include acute pancreatitis, chronic pancreatitis, autoimmune pancreatitis, pancreatic exocrine insufficiency, and pancreatic neoplasia. Among them, acute pancreatitis is the most common human disease of the pancreas. Therefore the present review focuses on the pathophysiology and current clinical management of acute pancreatitis. Although the condition is usually mild, about 25% of patients will develop complications such
Acknowledgements
This work was fully supported by the Competitive Earmarked Research Grant from the Research Grants Council of Hong Kong (Project Nos. CUHK4364/04M and CUHK4537/05M), awarded to PSL.
References (25)
- et al.
Current management of acute pancreatitis
J. Gastrointest. Surg.
(2005) - et al.
German Antibiotics in Severe Acute F Pancreatitis Study Group. Prophylactic antibiotic treatment in patients with predicted severe acute pancreatitis: A placebo-controlled, double-blind trial
Gastroenterology
(2004) - et al.
Platelet activating factor antagonism reduces the systemic inflammatory response in a murine model of acute pancreatitis
J. Surg. Res.
(2001) - et al.
Early antibiotic treatment in acute necrotising pancreatitis
Lancet
(1995) - et al.
Transdifferentiation of pancreas to liver
Mech. Dev.
(2003) - et al.
Inflammation and angiotensin II
Int. J. Biochem. Cell Biol.
(2003) - et al.
The role of the pancreatic renin–angiotensin system in acinar digestive enzyme secretion and in acute pancreatitis
Regul. Pept.
(2004) - et al.
Prophylactic and therapeutic treatments with AT1 and AT2 receptor antagonists and their effects on changes in the severity of pancreatitis
Int. J. Biochem. Cell Biol.
(2004) - et al.
Differential effects of saralasin and ramiprilat, the inhibitors of renin–angiotensin system, on cerulein-induced acute pancreatitis
Regul. Pept.
(2003) - et al.
The regulation of exocytosis in the pancreatic acinar cell
Cell. Signal.
(2002)
Treatment with bindarit, a blocker of MCP-1 synthesis, protects mice against acute pancreatitis
Am. J. Physiol.
Architecture of normal pancreas as revealed by retrograde injection
Cell Tissue Res.
Cited by (52)
Alterations in exocrine pancreatic function after acute pancreatitis
2024, PancreatologyThe role of asparagine synthetase on nutrient metabolism in pancreatic disease
2020, PancreatologyCitation Excerpt :These data further suggest that the pancreas has adapted to a high expression of ASNS to fulfill its special need for Asn. Acute pancreatitis is a painful-life threatening inflammatory disorder that is thought to initiate in the pancreatic acinar cell [49]. Despite the successful use of asparaginase in combination with other chemotherapeutics to transform 5-year survival for childhood ALL from 20% to 90% [50], the major challenge with associated asparaginase therapy is that 5–10% of users develop acute pancreatitis [9,51].
The antidiabetic properties of the hot water extract of kola nut (Cola nitida (Vent.) Schott & Endl.) in type 2 diabetic rats
2019, Journal of EthnopharmacologyCitation Excerpt :This result also suggests a postprandial glycemic control potential of C. nitida. Nevertheless, the elevated pancreatic amylase activity of the untreated diabetic animals (Table 3) seems to contradict the concomitant loss and disintegration pancreatic acinar cells (Fig. 3), which is a functional component of the pancreatic exocrine that synthesizes, stores and secrets digestive enzymes like α-amylase (Leung and Ip, 2006). This discrepancy may be attributed to the high food intake (polyphagia) in this group of animals, which, perhaps, lead to increased secretion and activity of pancreatic amylase and vice versa in the C. nitida-treated diabetic animals.