Peptide YY does not affect cell cycle while improving pancreatitis and increasing pancreatic duct cell growth

GASTROENTEROLOGY Vol. 118, No.4

A1156 AGA ABSTRACTS

5320 PAF DOES NOT HAVE A THERAPEUTIC EFFECT ON PANCRE· ATIC MICROCIRCULATION IN ACUTE EXPERIMENTAL PAN· CREA TITIS OF THE RAT. Wolf J. Tiefenbacher, Oliver Mann, Claus G. Schneider, Dietrich Kluth, Jakob R. Izbicki, Christian Bloechle, Univ Hosp Eppendorf, Hamburg, Germany. Background Platelet-activating factor mediates microcirculatory disorders in acute pancreatitis Aim of the study was to delineate the effect of platelet-activating actor (PAF) antagonist WEB-2086 on microcirculatory disorders in acute pancreatitis of different severity. Materials and Methods: Fasted wistar rats were anesthesized with pentobarbital (40mgfkg BW i.p.)and ketamine (lOmgfkg BWi.p.) allowing spontaneous breathing. Ringer's lactate was infused for fluid resuscitation keeping MAP and heart rate within 10% of baseline. PAF-Antagonist WEB 2086 or vehicle were injected i.v. 15 min after infusion of saline (i.d. O,9%,OAml for 5 min, 25mmHg), or infusion of sodium taurocholate (i.d. 4%, OAml for 5 min, 25mmHg), the combination of glycodeoxycholic acid (i.d. lOrnrnl/l, l.Oml/kg KG) and Cerulein (i.v. 5 p.g/kg BWlhr for 6 hrs.), or infusion of cerulein (i.v. 5 p.gfkg BWlhr for 6 hrs.).After injecting Acridine Orange (I %, 1,2ml kg BW) to label leukocytes, pancreatic microcirculation was observed in-vivo using fluorescence microscopy. The diameter of interlobular arterioles, number of perfused capillaries, flow rate, and leukocyte adherence in the postcapillary venules were determined. Blood samples were taken to determine serum amylase activity and trypsinogen-activating peptide(TAP). Animals were sacrifized six hours after induction of pancreatitis, the volume of peritoneal exsudate was estimated, and histologic pancreatic damage was assessed using an established pancreatitis severity score. Results: Intraductal infusion of 0.9% NaCI resulted in LA of up to 14%. The perfusion of capillaries remained almost completely intact. Histopathologic damage scored 0,5 points. In sodium taurocholate pancreatitis, collapse of microcirculation occurred within 171 seconds with a LA of 74%. Number of perfused capillaries,TAP-level and histological score showed no significant differences between therapeutic and control group. In intermediate pancreatitis model, perfusion was preserved in 25% of capillaries as opposed to 17% in controls (ns.) LA was 64% and 63%, respectively. TAP was reduced from 14,12 vs.2,13 nrnol/l. Histoscore showed no significant difference. In edematous pancreatitis number of perfused capillaries was equally preserved. Conclusions: In experimental pancreatitis of graded severity therapeutic intervention with PAF-antagonist WEB 2086 does not exert a protective effect on pancreatic microcirculation and pancreatic tissue injury.

and pancreatic pseudocyte compressing intrahepatic biliary ducts. The patient was treated by jejunal feeding, which was effective in part because of the reduction of abdominal pain and serum amylase level (by 550%). However, the size of the pseudocyte and the severity of jaundice had increased (by 54% and 117% respectively). We did endoscopic retrograde cholangio-pancreatography (ERCP), papillotorny, and a double stent implantation which upper part were situated to cross the pseudocyte-caused obstruction. Then, an endoscopic cysto-gastrostorny had been performed, and a 7 F diameter stent was implanted into puncture whole. After this procedure, a naso-cystic drain was implanted, and we introduced a 6-day antibiotic lavage. The treatment revealed to be successful, since the pseudocyte disappeared, and the obstructive jaundice healed. Then, we removed the naso-cystic drain. The patient left the hospital without complaints. The naso-cystic stent was removed endoscopically 4 month later, while the stents still remained in the choledochus. ~Endoscopic treatment of CCP-caused jaundice appears to be a good alternative approach besides surgical intervention.

5323 PEPTIDE YY DOES NOT AFFECT CELL CYCLE WHILE IMPROVING PANCREATITIS AND INCREASING PANCREATIC DUCT CELL GROWTH. Shirin Towfigh, Tracy Heisler, Natalie Simon, David W. McFadden, UCLA Dept of Surg, Los Angeles, CA. We have previously shown that peptide YY (PYY), an endocrine regulatory peptide, has a mitogenic effect on pancreatic duct cells while improving pancreatitis. We hypothesize that this is partly due to changes in cell cycle. Pancreatic duct cells, ARIP, were cultured in the presence of caerulein (0.1 p.M), PYY (200 pmol), or a combination pretreated with PYY overnight prior to addition of caerulein. DNA staining for rapid fluorocytometric cell cycle analysis was performed at 24, 48, and 72 hours. Analysis of variance and Students' t-test were used for data analysis. Pancreatic duct cells were predominantly in the Go-GI phase (86.8% ± 1.3) with few in the S (9.7%± 1.7) and G2-M phases (3.4%± 1.1). Neither PYY, caerulein, nor combination groups affected cell cycle, despite showing mitogenic and pancreatitis-inducing effects (p>0.05). Although PYY's mechanism of action remains unclear, this data suggests for the first time that PYY does not act by altering cell cycle, despite its mitogenic and protective effects on duct cells in pancreatitis. Effects ofPYY on pancreatic duct cell cycle.

Go·G, phase

S phase

G,·M phase

858±17 867±0.3 88.0±0.7 0.07

107±5.0 94±15 90±2.2 048

35±2.2 38±09 30±1.4 073

5321 MORPHOLOGICAL CHANGES AND MORPHOLOGICAL·FUNCTIONAL CORRELATIONS IN ACUTE EXPERIMANTAL ISCHEMIAlREPERFUSION PANCREATITIS IN RATS. AN IMPORTANT ROLE OF TUBULAR COMPLEXES FORMATION. Romana Tomaszewska, Artur Dembinski, Zygmunt Warzecha, Piotr Ceranowicz, Jerzy Stachura, Dept of Pathology, Jagiellonian Univ Med Sch, Krakow, Poland; Dept of Physiology, Jagiellonian Univ Med Sch, Krakow, Poland. The etiology of acute pancreatitis, apart from alcohol abuse and cholelithiasis may also include a vascular component resoponsible for pancreatic ischemia. It is now acknowledged that chronic pancreatitis may be a consequence of the acute variant, but it remains unclear what factors influence this sequence of morphological changes. In order to clarify this issue we proposed a model of experimental acute pancreatitis in rats induced by a 30 min reduction of blood flow in inferior splenic artery followed by reperfusion. Rats were sacrificed at lh, 12h, 24h, and 2. 3. 5, 7. 14,21,28 days after cessation of ischemia. We performed histopathological examination of pancreatic tissue and measured pancreatic blood flow, plasma amylase activity and interleukin-I J3 concentration. The present findings indicate that transient pancreatic ischemia leads to the development of acute necrotising-heamorrhagic pancreatitis, The morphological features of acute inflammation are correlated positively with functional disorders. In some cases the features of chronic pancreatitis may appear transiently in the acute inflammation. whereas the repair if postinflammatory injury involves the regeneration of acinar cells.

5322 COMPLEX ENDOSCOPIC TREATMENT OF SUCH COMPLICA· TION OF CHRONIC CALCIFICATING PANCREATITIS AS OB· STRUCTIVE JAUNDICE CAUSED BY A PANCREATIC PSEUDO· CYTE, Lajos Topa, Terez Szajbert, Laszlo Balint. Ferenc Laszlo. 2nd Dept of Medicine, St Imre Univ Teaching Hosp, Budapest, Hungary; Inst of Experimental Medicine, Hungarian Acad of Sci, Budapest, Hungary. ~It has been demonstrated that almost 50% of the patients with chronic calcificating pancreatitis (CCP) should be surgically operated, because of such complication as obstructive jaundice caused by the compression by pancreatic pseudocystes. --> In the present study, we investigated a case with CCP in which obstructive jaundice and pseudocyst developed, however, the patient was treated endoscopically. ~CCP was diagnosed in a 53-old male patient in 1994. The patient follow-up showed no complication until 1998, when abdominal pain and obstructive jaundice occured. The reason of the complaint revealed to be acute exacerbation of pancreatitis

PYY Caerulein PYY+Caerulein p.value

5324 THE BALANCE OF MITOGENESIS AND APOPTOSIS IN THE RAT PANCREAS IN RESPONSE TO CCK·8. Lena Trulsson, Thomas Gasslander, Johan Permerth, Joar B. Svanvik, Dept of Surg, Linkoping, Sweden. Administration of the endogenous peptide CCK-8 may cause exocrine pancreatic hypertrophy and hyperplasia due to stimulation of the CCK-A receptor. The present study analyses the pancreatic growth homeostasis when pancreatic growth is stimulated by a continuous infusion of CCK-8 for three days. Thirty Wistar rats were studied for pancreatic wet wei~ht, protein and DNA contents in response to CCK-8. Incorporation of Hthymidine (LIJ, which reflects the mitogenesis, was measured in acinar and ductal cells. The caspase-J activity, which reflects apoptosis, was measured in the pancreatic tissue. Results: There were dose-dependent increases in: pancreatic wet weight, protein and DNA contents, 3H-thymidine incorporation in both acinar and ductal cells and caspase-3 activity in pancreatic tissue. Conclusion: Stimulation of the pancreas with CCK-8 causes an increased proliferation which is counterbalanced by a moderately raised apoptosis. The proliferation outweighs the apoptosis causing a hyperplasia. CCK·8 /llllkgl24h 0 2.4 12 24 48

Pane.ww mgl100g

DNA

Protein mglpwwl1OOgbw

410±15 423±6 680±32 728±18 842±41

54±03 57±03 66±06 70±02 81±04

611±21 58.1±13 791±68 823±35 101±4.l

Casp.·3 rel.eontr

acinar

ductal

100±6 109±9 140±7 159±14 189+18

o6±0 04

L1,%

1.0±007 21±0.04 24±018 47±057

06±011 10±0.61 18±0.46 24±018 2.7+0.56