Advances of bioactive peptides in hepatic ischemia/reperfusion injury / 国际外科学杂志

Hepatic ischemia/reperfusion injury (HIRI) occurs in liver surgical interventions or systemic hemorrhagic shock, especially in liver transplantation, which can lead to serious postoperative complications and strongly threats the utilization of marginal donor livers and the prognosis of recipients. Here, how to effectively intervene HIRI has always been the important topic in liver surgery. The pathogenesis of HIRI has been gradually elucidated, but no effective prevention and treatment measures have been performed to reduce the injury in clinic. Peptides are small molecules without a quaternary protein structure, which can effectively regulate physiological processes such as stress and metabolism in the body, and participate in the occurrence and development of diseases. Recently, with the successful application of insulin and other peptides in the bedside, the effect of bioactive peptides on HIRI has been attracting wide attention, numbers of studies have confirmed that bioactive peptides have great potential for liver protection during HIRI. This article reviews the roles of bioactive peptides in HIRI and provides new sight and reference to protect liver from HIRI.

Fetal Topographical Anatomy of the Pancreatic Head and Duodenum with Special Reference to Courses of the Pancreaticoduodenal Arteries

PURPOSE: The purpose of this study is to provide better understanding as to how the "double" vascular arcades, in contrast to other intestinal marginal vessels, develop along the right margin of the pancreatic head. MATERIALS AND METHODS: In human fetuses between 8-30 weeks, we described the topographical anatomy of the vessels, bile duct, duodenum as well as the ventral and dorsal primordia of the pancreatic head with an aid of pancreatic polypeptide immunohisto-chemistry. RESULTS: The contents of the hepatoduodenal ligament crossed the superior side of the pylorus. Moreover, the right hepatic artery originating from the superior mesenteric artery ran along the superior aspect of the pancreatic head. An arterial arcade, corresponding to the posterior pancreaticoduodenal arteries, encircled the superior part of the pancreatic head, whereas another arcade, corresponding to the anterior pancreaticoduodenal arteries, surrounded the inferior part. The dorsal promordium of the pancreas surrounded and/or mixed the ventral primordium at 13-16 weeks. Thus, both arterial arcades were likely to attach to the dorsal primordium. CONCLUSION: The fetal anatomy of the pancreaticoduodenal vascular arcades as well as that of the hepatoduodenal ligament were quite different from adults in topographical relations. Thus, in the stage later than 30 weeks, further rotation of the duodenum along a horizontal axis seemed to be required to move the pylorus posterosuperiorly and to reflect the superior surface of the pancreatic head posteriorly. However, to change the topographical anatomy of the superior and inferior arterial arcades into the final position, re-arrangement of the pancreatic parenchyma might be necessary in the head.

Different Regulation of Atrial ANP Release through Neuropeptide Y2 and Y4 Receptors

Neuropeptide Y (NPY) receptors are present in cardiac membranes. However, its physiological roles in the heart are not clear. The aim of this study was to define the direct effects of pancreatic polypeptide (PP) on atrial dynamics and atrial natriuretic peptide (ANP) release in perfused beating atria. Pancreatic polypeptides, a NPY Y4 receptor agonist, decreased atrial contractility but was not dose-dependent. The ANP release was stimulated by PP in a dose-dependent manner. GR 23118, a NPY Y4 receptor agonist, also increased the ANP release and the potency was greater than PP. In contrast, peptide YY (3-36) (PYY), an NPY Y2 receptor agonist, suppressed the release of ANP with positive inotropy. NPY, an agonist for Y1, 2, 5 receptor, did not cause any significant changes. The pretreatment of NPY (18-36), an antagonist for NPY Y3 receptor, markedly attenuated the stimulation of ANP release by PP but did not affect the suppression of ANP release by PYY. BIIE0246, an antagonist for NPY Y2 receptor, attenuated the suppression of ANP release by PYY. The responsiveness of atrial contractility to PP or PYY was not affected by either of the antagonists. These results suggest that NPY Y4 and Y2 receptor differently regulate the release of atrial ANP.

Establishment of the Guideline for the Anatomical Resection of the Ventral and Dorsal Portion of the Pancreatic Head

PURPOSE: This study was designed to delineate the anatomical details of the pancreatic head for a ventral or dorsal segmental pancreatic resection along the embryological fusion plane, and to determine the feasibility of both procedures. METHODS: The resected pancreaticoduodenectomy specimens were analyzed (n=8), with the pancreatic and distal common bile ducts visualized by pancreatography (n=8). Immunohistochemical staining, with pancreatic polypeptide (PP), was performed in serially sliced specimens (n=3). The immunohistochemical and H&E staining were performed to evaluate the composition of the anatomical structures of the two differentially stained pancreas. RESULTS: What was presumed to be the embryological fusion plane was discovered between two differentially stained segments. This started just above the anterior inferior pancreaticoduodenal artery, directed to the posterior superior part of the pancreatic head and ended at the anterior surface of the distal common bile duct. The duct of Wirsung and the distal common bile duct were included in the posterior segment of the pancreas (ventral pancreas). There were two types of pancreatic duct arrangement, with the differences between the two types being; (1) the distance between the fusion point of the ventral and dorsal pancreatic ducts and the papilla of Vater, and (2) the stream of the Santorini duct. The branches of the pancreatic ducts were scattered over the entire pancreatic head region in multiple-directions. CONCLUSION: The fusion plane of the ventral and dorsal pancreas seems to initiate just above the anterior inferior pancreaticoduodenal artery, in a posterior-superior direction along the anterior surface of the distal common bile duct. A ventral pancreatectomy seems an impractical procedure with regard to the postoperative morbidity and operative difficulty, while a dorsal pancreatectomy seems to be more practical and feasible in its clinical aspects.

Mechanism of action of pancreatic polypeptide (PP) on pancreatic exocrine secretion in isolated rat pancreas

Aim of this study was to investigate if pancreatic polypeptide (PP) reduced the insulin action via the intra-pancreatic cholinergic nerves in the isolated rat pancreas. The pancreas was isolated from rats and perfused with intra-arterial infusion of modified Krebs-Henseleit solution containing 2.5 mM glucose at a flow rate of 1.2 ml/min. Simultaneous intra-arterial infusion of insulin (100 nM) resulted in potentiation of the pancreatic flow rate and amylase output which were stimulated by cholecystokinin (CCK, 14 pM). These potentiating actions of insulin on the CCK-stimulated pancreatic exocrine secretion were completely abolished by administration of rat PP. Vesamicol, a potent inhibitor of vesicular acetylcholine storage, and tetrodotoxin (TTX) also significantly reduced the combined actions of insulin and CCK. Administration of carbamylcholine, an acetylcholine agonist, completely restored the vesamicol-or TTX-induced inhibition of the potentiation between insulin and CCK. Also rat PP failed to attenuate the restoring effect of carbamylcholine. Electrical field stimulation (15-30 V, 2 msec and 8 Hz) resulted in a significant increase in the pancreatic flow rate and amylase output in voltage-dependent manner. Effects of electrical field stimulation were augmented by endogenous insulin. Rat PP also suppressed the pancreatic exocrine secretion stimulated by electrical field stimulation. These observations strongly suggest that PP inhibits the potentiating actions of insulin on CCK-stimulated pancreatic exocrine secretion by suppression of the intra-pancreatic cholinergic activity in the isolated rat pancreas.

PANCREATIC POLYPEPTIDE SECRETION IN SIMPLE OBESITY AND TYPE II DIABETES MELLITUS / 中华内分泌代谢杂志

Using pancreatic polypeptide (PP) RIA kit prepared in our laboratory, serum levels of PP were observed in obese, type II diabetics with or without insulin treatment and 18 normal controls. The results showed that obese subjects presented hypersecretion of PP, hyperinsulinemia and hyperglycemia. Diabetics presented hypersecretion of PP with low levels of insulin and G-peptide. Possible explanations for hypersecretion of PP were commented.