bile salts and not cholesterol or phospholipid stimulate mucin secretion by cultured dog gallbladder...
A l 1 0 0 AASLD ABSTRACTS GASTROENTEROLOGY, Vol. 108 , No. 4
NECESSITY OF A RECOVERY PHASE AFTER IN-SITU LIVER PREPARATION TO IMPROVE HEPATIC MICROCIRCULATION PRIOR TO ORGAN PRESERVATION. E.Klar, T.Kraus, B.0sswald, A.Mehrabi, J.Bleyl, G,Otto, C.Herfarth. Dept. of Surgery, University of Heidelberg, Germany
During explantation preparation of the liver including hilar structures is usually performed prior to perfusion with storage solution. It was the aim of the current study to quantify the mechanical effect of surgical manipulation on the hepatic microcirculation by means of thermodiffusion technique. Method: In 9 pigs bile duct, hepatic artery, and portal vein were exposed followed by transsection of the lesser omentum. Transit-time ultrasound flowprobes were placed around hepatic artery and portal vein to measure whole organ blood flow. A thermodiffusion probe was implanted into the medial left liver lobe. Hepatic microperfusion and total blood f low were quantified simultaneously 2 rain, 5 rain, and 10 rain after completion of the surgical preparation. Shunt fraction = shunt flow as percentage of total liver blood flow. Results: An impairment of hepatic microcirculation was detected at a maximum 2 rain after cessation of Surgical manipulation. Thereafter a gradual increase of capillary perfusion in parallel with a reduction in shunt flow was recorded reaching significance at 10 rain.
time after cessation of liver preparation 2 rain 5 min 10 min
total liver blood flow [ml/100glmin] 150+13 149+13 137+11 perfusion [ml/100g/min] 59+7 65+6 75+8* shunt fraction [%] 59 + 6 54 + 5 434- 6"
mean+SEM, *p<0,05 10 rain vs.5 rain, paired t-test Conclusion: A pronounced impairment of hepatic microcirculation is induced by in-situ preparation of the liver prior to explantation. Due to increased shunt f low perfusion of the liver with storage solution could become ineffective if performed directly after surgical manipulation as in case of missing heart explantafion. A recovery phase of 10 minutes results in a significant increase of hepatic capillary perfusion in correlation with a reduction in shunt flow.
• BILE SALTS AND NOT CHOLESTEROL OR PHOSPHOLIPID STIMULATE MUCIN SECRETION BY CULTURED DOG GALLBLADDER EPITHELIAL CELLS: JH Klinksooor#, H Azzouz#, R Kuver*, CE Savard*, D Oda°, GNJ Tytgat#, AK Groen#, and SP Lee*. #Dept. of Gastroenterology, Academic Medical Center, Amsterdam, The Netherlands, °Departments of Medicine and Oral Biology, University of Washington and *VA Medical Center, Seattle, Washington.
Introduction: Recently we demonstrated, using cultured dog gallbladder epithelial (DGBE) cells, that bile salts (BS) and not cholesterol (CH) stimulate mucin secretion by the gallbladder (Hapatology 1994:20:A685). In this study we investigated whether CH crystals and phospholipids (PC) can influence mucin secretion and extended our studies towards the mechanism by which BS regulate mucin secretion. Methods: Model biles (MB) or BS were applied to the luminal side of confluent monolayers of DGBE cells, grown on Transwell inserts. Mucin secretion was measured as described previously. Cell viability was assessed by measuring leakage of lactate dehydrogenase (LDH). Intracellular cAMP levels were measured as described by Kuver et al (Am.J.Physiol, in press) Results: The effect of MB with different phospholipid concentrations on mucin secretion was investigated (4.6 to 1.9 mM PC, 1.2 mM CH, 20 mM taurocholic acid). Independent of their CSI (0.7 to 1.3) the MB all increased mucin secretion to an average 240% as compared to the control incubation, p<0.01. Incubation of s supersaturated MB for 4 days at 37°C, causing massive CH crystallization, had no effect on the ability of this MB to increase mucin secretion, confirming our previous conclusion that BS is the MB component responsible for the stimulatory effect. Comparing the effect of different BS on mucin secretion we found that all BS tested caused a dose-dependent increase in mucin secretion. The hydrophobic BS taurochenodexycholate (TCDC) and taurodeoxycholate (TDC) were more effective than the hydrophylic BS taurocholate (TC) and taurourso-deoxycholate (TUDC) in stimulating mucin secretion, but at high concentrations caused significant LDH release from the cells. With 40 mM of TUDC a maximum mucin secretion of 350% of control was obtained, no cytotoxicity was observed. No effect of 5 and 10 mM of TC on intracellular cAMP levels could be demonstrated. Conclusions: Bile salts, and not cholesterol, CH crystals or phospholipid, stimulate mucin secretion by the gallbladder. BS cause a dose-dependent increase in mucin secretion, hydrophobic BS being more potent than hydrophilic BS. In contrast to Prostaglandin E2 (Kuver et all BS do not stimulate mucin secretion by increasing intracellular cAMP levels. The mechanism by which BS influence mucin secretion is not yet clear and needs further investigation.
• ITO CELLS SYNTHESIZE PLASMINOGEN ACTIVATOR INHIBITOR-l: REGULATION BY CORTICOSTEROIDS
AND PLASMINOGEN ACTIVATOR. T.Knittel, P.Fellmer, G.Ramadori.
Dept. of Internal Medicine, University of G6ttingen, Germany.
Plasminogen activator inhibitor-1 (PAI-1) plays a crucial role in the regulation of extracellular matrix (ECM) degrading enzymes like metallopruteinases and of fibrogenic mediators like TGF-g through inhibition of plasminogcn activation. Since Ito cells, the principal matrix producing cell during liver fibrogenesis, might also affect ECM accumulation by modulation of ECM degradation and of activities of fibrogenic mediators, the aim of our study was to test whether Ito cells synthesize PAI-1 and to study the regulation of PAI-1 production in Ito cells. Methods: Ito cells, hepatocytes, Kupffer cells and endothelial cells were isolated from rat livers by standard methods and were endogenously labeled using 35S-methionine in primary culture. PAI-1 biosynthesis was studied by immunoprecipitation of endogenously labeled protein followed by SDS-PAGE and autoradiography. Using the same techniques PAI-1 production was analysed in PAI-1 expressing (positive control) or not expressing (negative control) hepatoma cells. Regulation of PAI-1 synthesis was analyzed by 24 h incubation with tissue plasminogen activator (tPA) and Dexamthason (Dex). Results: SDS-PAGE of immunoprecipitates obtained with different antibodies directed against human or fat PAI-1 and samples derived from endogenously labeled Ito cells revealed an protein with an apparent Mr of 53 kD which was identified as PAI-1 by blocking experiments with unlabeled PAI-1 and by use of hepatoma cells as positive and negative controls. Interestingly, no evidence for t-PA production was found in Ito cells. Among the various types of liver cells PAI-1 synthesis was present in Ito cells and endothelial cells, low levels were detected in hepatocytes and no major PAI-1 synthesis was detected in Kupffer cells. PAI-1 synthesis was apparent both in "resting" as well as "activated" Ito cells. Pulse chase analysis demonstrated synthesis and secretion of the protein. Among the mediators tested so far, Dex increased PAI-1 production and also tPA regulated levels of newly synthesized PAI-1 in ito cells. Conclusions: Apart from their role as the principle ECM producing cell of fibrotic liver, Ito cells might regulate ECM accumulation during liver fibrosis by modulating the activities of matrix degrading enzymes and of fibrogenic mediators through the production of PAI- 1.
Repeat Hepatic Resections for Colorectal Metastases to the Liver
WT Knoefel, C Brunken, M Gundlach, X Rogiers, JR Izbicki, CE Broelsch
Department of Surgery, University of Hamburg, Hamburg, Germany
Introduction: A surgical approach to recurrent colorectal metastases to the liver is rarely taken. To specify a rational approach to these lesions we reviewed our experience of the last 6 years.
Methods: 11 repeat hepatectomies were performed in 10 patients over the last 6 years at our department. The median interval since first resection was 12 months. 5 primary resections were anatomic resections, 6 were atypical resections. Exclusion of extrahepatic disease, control of the primary tumor and intraoperative ultrasound to exclude further intrahepatic disease were required in all patients.
Results: There was no perioperative mortality. 2 patients developed pleural effusions that were treated by conservative means, Performed operations were: 6 hemihepatectomies, 2 segmentectomies, and 3 wedge resections. 2 of these were extended resections. In 10 patients no residual tumor was left behind whereas in 1 patient the resection margin was microscopically involved. Median postoperative hospital stay was 11 days. A median of 2 transfusions (maximum 4) were required. The median survival is currently 27 months. 3 patients died from tumor relapse. The median disease-free survival is 20 months. 5 patients developed a tumor relapse after a median interval of 13 months. 2 of these relapses were intrahepatic. Relapse was treated by liver resection (n = 1), hepatojejunostomy (n = 1), or chemotherapy (n = 3).
Conclusions: Hepatic resection for recurrent colorectal metastases to the liver is safe. Prognosis of this highly selected group is comparable to that of patients undergoing primary resections. Approach to recurrent metastases should therefore be as aggressive as to primary metastases.