The influence of thrombopoietin (TpO) on human erythropoiesis. In vitro studies--clinical implications

beta-Glucuronidase of human or bacterial origin may deconjugate bilirubin diglucuronide, causing pigment gallstones. Intrinsic interference by biliary compounds must be minimized for accurate assay of beta-glucuronidase. We report a modified ion-pair extraction of interfering substances by tetrahexylammonium chloride (THAC) in ethyl acetate in the presence of albumin, and a microtitre plate assay for biliary beta-glucuronidase activity in bile with the substrate p-nitrophenol-glucuronide. Adding albumin improved the recovery of beta-glucuronidase activity to 99.8% (CV 1.9%), and 92.2% of the bilirubin in bile samples was extracted in one step. Competitive inhibition was overcome by increasing the substrate concentration. In endoscopically obtained common duct bile from 44 patients, five different beta-glucuronidase activity peaks were identified, at pH 3.9, 4.8, 5.3, 5.8 and 7.2. The pH profiles were classified into one bacterial pattern and five patterns for presumed human beta-glucuronidase. Of the latter patterns, four displayed dual activity peaks. In a second sample, obtained at follow up in four patients, their original pH profile was maintained. In conclusion, using the modified purification and assay system, we found functionally diverse subcategories of human beta-glucuronidase with respect to activity at variable pH. Our results indicate that several pH optima have to be taken into consideration in order to clarify the role of human biliary beta-glucuronidase in the pathogenesis of pigment gallstones. Bacterial beta-glucuronidase activity was associated with duodenal diverticula (p < 0.05) and common duct stones (p < 0.05).     

Cholelithiasis in Taiwan. Gallstone characteristics, surgical incidence, bile lipid composition, and role of beta-glucuronidase

The nature and occurrence of gallstones in Taiwan and their etiologic factors might not be the same as in Western countries and warranted a systematic investigation. Gallbladder biles and gallstones were obtained at surgery from 100 and 74 patients, respectively. Common duct bile and stones were either drained through an indwelling common duct T-tube or aspirated through a nasobiliary catheter in 108 patients. Gallstones were analyzed for bilirubin, cholesterol, bile acid, calcium, and residue, and biles for bile acid, cholesterol, phospholipid, bilirubin, and beta-glucuronidase. There were four major kinds of gallstones in Taiwan: cholesterol/mixed stones, high-residue black formed pigment stones, low-residue brown formed pigment stones, and muddy pigment stones. The surgical incidence of all types of stones increased steadily during the past four decades. During the past 15 years the relative frequencies for mixed, formed pigment, and muddy pigment stones had been roughly 40, 40, and 20%, respectively, with a further increase in the mixed stones and a decrease in the muddy pigment stones in recent years. Improvement of nutritional status and living standards might contribute to such changes. Cholesterol content in the common duct and gallbladder biles was higher in the mixed stone group than in other groups. Bacterial beta-glucuronidase activity was detected in 53% of patients with muddy pigment stones. Endogenous beta-glucuronidase activity and concentration were also highest in this group, intermediate in the formed pigment and mixed stone group, and lowest in the control. We concluded that hypercholesterobilia was responsible for increasing incidence of mixed stones during the past two decades, while both bacterial and human beta-glucuronidase might contribute to pigment cholelithiasis.     

The ability of bile to scavenge superoxide radicals and pigment gallstone formation in guinea pigs

After partial ligation of the common bile duct (CBD) of guinea pigs, 14 of 16 animals developed pigment gallstones within one week (S group). Intraperitoneal injection of Vit. E and C, each 10 mg/kg daily from 3 days before CBD ligation to one week after the operation (S+V group), decreased the gallstone incidence to 5/14 (exact probability < 0.01). The gallstone incidence in the control group, that only received laparotomy without ligation of the CBD, was 0/15. Biochemical analysis of the gallbladder bile showed that stricture of the CBD was associated with a significant increase in levels of unconjugated bilirubin (UCB) and Ca2+ (p < 0.05 and < 0.01). Simultaneously the scavenging rate (SR) of superoxide radical in bile significantly decreased (p < 0.05). Comparing S+V group with S group, the effect of Vit. E and C on the concentrations of UCB and Ca2+ in bile was not significant (both p > 0.05), but Vit. E and C normalized the SR, and the difference between S group and S+V group was significant (p < 0.05). These results suggested that Vit. E and C, known as antioxidants, enhanced the ability to scavenge oxygen radical in S+V group; and that in addition to the increases of UCB and Ca2+ concentrations, the participation of oxygen radicals might be of importance for pigment gallstone formation induced by bile duct obstruction.     

Gallstone formation and gallbladder bile composition after colectomy in dogs

A high prevalence of gallstones has been described in patients following colectomy. The aim of this study was to examine whether lithogenicity is attributed to colectomy. In the present study, changes in gallbladder bile composition and the mechanism of gallstone formation after colectomy were examined in dogs. Ten mongrel dogs underwent restorative proctocolectomy. Seven dogs which received sham operations served as controls. Over a 12-week postoperative period, samples of gallbladder bile, formed gallstones and serum were collected and analyzed. In 7 of the 10 (70%) colectomized dogs, gallstones were found in the gallbladder, while the control dogs had no stones. Macroscopically the gallstones were similar to black pigment stones observed in humans. Chemical analysis and Fourier transform-infrared spectroscopy examination revealed that the stones were composed mainly of sodium bilirubinate and proteins, with minor amounts of calcium salts and cholesterol. Significant increases in biliary pH and concentrations of ionized calcium and unconjugated bilirubin were observed in the gallbladder bile of the colectomy group compared with that of the control group. The total bile acid and total bilirubin concentrations were significantly decreased in the colectomy group. Cholesterol crystal nucleation did not occur. The inhibitory effect of gallbladder bile on calcium carbonate precipitation in an in vitro assay system was preserved even after colectomy. In conclusion, proctocolectomy increases the concentration of unconjugated bilirubin in gallbladder bile and induces pigment gallstones which are composed mainly of sodium bilirubinate and proteins since calcium ions and cholesterol are stabilized in dogs.     

Treatment of extrahepatic occlusive jaundice with activated charcoal hemoperfusion in dogs

To find the feasibility of treatment for congenital bile duct atresia, we studied the usefullness of extracorporeal hemoperfusion over activated charcoal in canine obstructive jaundice. One, three and five weeks after ligation and disection of common bile duct in 5 dogs we performed the hemoperfusion over activated charcoal extracorporeally (group 3). In this animals we examined hematological and blood coagulation studies, serum electrolyte levels, kidney function tests and liver chemistries. As control in 5 animals we carried out after sham operation the perfusion without common bile duct ligation (group 2) and in 5 animals only common bile duct ligation without perfusion (group 1). In the liver chemistries we found 2 weeks after 2nd and 3rd perfusion (5 and 7 weeks after bile duct ligation) lower levels of serum bilirubin, GOT, GPT and SDH in treated group than in non-treated jaundiced animals. It suggest the effectiveness of hemoperfusion with activated charcoal in the treatment of occlusive jaundice. There were no alteration in the hematological studies, serum electrolyte levels and kidney function tests. PT and PTT was prolonged in the jaundiced animals there were no significant differences with and without hemoperfusion.     

Biliary electrolytes and enzymes in patients with and without gallstones

pH, osmolarity, various electrolytes, nine enzymes, and bile acid were determined in hepatic and gallbladder biles from 108 and 100 patients, respectively, relating to various types of gallstones. The pH, osmolarity, and electrolytes were essentially identical in all groups of patients except for slightly higher Ca and Mg in the hepatic bile in patients with muddy pigment stones. The gallbladder bile contained much higher inorganic cations yet remained isosmotic as a result of their sequestration into bile acid micelles. Excluding extremely high values, the activities of nine enzymes in the bile showed only minor differences among four groups of patients except for a high beta-glucuronidase activity in the hepatic bile in patients with muddy pigment stones. The biliary baseline activities of various enzymes and the relation to their serum levels were determined by their sources and subcellular localization in the hepatocytes. We concluded that biliary electrolytes and enzymes were basically similar in patients with and without gallstones except for higher levels of Ca, Mg, and beta-glucuronidase in hepatic bile in patients with muddy pigment stones.     

The role of endothelial nitric oxide synthase in the pathogenesis of a rat model of hepatopulmonary syndrome

BACKGROUND & AIMS: The hepatopulmonary syndrome occurs when intrapulmonary vasodilatation causes impaired arterial gas exchange in liver disease. The pathogenesis is poorly understood, although nitric oxide may be involved. Common bile duct ligation in the rat is a model of the hepatopulmonary syndrome, but no studies have evaluated NO in pulmonary vasodilatation in this model. The aim of this study was to determine whether NO contributes to intrapulmonary vasodilatation after bile duct ligation. METHODS: Endothelial and inducible NO synthase (NOS) levels and localization and NO activity in pulmonary artery rings were assessed after bile duct ligation. RESULTS: Pulmonary endothelial NOS levels increased and alveolar vascular staining was enhanced after bile duct ligation. No change in pulmonary inducible NOS levels or localization was detected. Increased endothelial NOS levels correlated with alterations in gas exchange and were accompanied by enhanced NO activity and a blunted response to phenylephrine, reversible by NOS inhibition, in pulmonary artery rings. Portal-vein-ligated animals, which do not develop intrapulmonary vasodilatation, had no changes in pulmonary NOS production or in NO activity in pulmonary artery rings. CONCLUSIONS: NO, derived from pulmonary vascular endothelial NOS, contributes to intrapulmonary vasodilation in animal hepatopulmonary syndrome.     

Retained common bile duct stones after endoscopic sphincterotomy: temporary and longterm treatment with biliary stenting

Basket extraction after endoscopic sphincterotomy failed to clear the bile ducts immediately in 85 (30%) of 283 consecutive patients with common bile duct stones. Temporary biliary drainage was established by the insertion of a single 7 Fr double pigtail stent before further planned endoscopic attempts at stone removal. In 84 patients (21 male: 63 female, mean age 77 years) this measure relieved biliary obstruction, mean serum bilirubin falling from 101 to 18 umol/l by the time of the second endoscopic retrograde cholangiopancreatography. Six patients died from non-biliary causes with temporary stents in situ. Common bile duct stone extraction was achieved endoscopically in 50 of the remaining 79 patients after a mean of 4.3 months (range 1-12), 34 (68%) requiring only one further procedure. Three patients were referred for biliary surgery. Single stents were also effective for longterm biliary drainage in the remaining 26 elderly patients with unextractable stones. The main biliary complication of stenting was 13 episodes of cholangitis but all except one responded to medical treatment and early stent exchange. If common bile duct stones remain after endoscopic sphincterotomy, a single 7 Fr double pigtail stent is effective and safe for temporary biliary drainage before further endoscopic attempts at duct clearance and for longterm biliary drainage especially in the old and frail.     

Increased neutrophil function induced by bile duct ligation in a rat model

Neutrophil function was studied in rats with common bile duct ligation. Superoxide production stimulated by phorbol myristate acetate, opsonized zymosan or formyl-methionyl-leucyl-phenylalanine; phagocytosis; and chemotaxis were significantly greater in neutrophils from rats with common bile duct ligation than in sham-operated control rats. Enhanced neutrophil activity was observed within 12 hr of bile duct ligation; it remained increased during the 15-day study. Preincubation of neutrophils from control rats with sera of rats with common bile duct ligation did not increase superoxide generation. This suggests that the high superoxide production observed in neutrophils of rats with common bile duct ligation was not an immediate effect of the serum. Neutrophils of rats with portal vein ligation exhibited normal activity, indicating that portal systemic shunting per se is not the underlying mechanism for increased activity. The elevated levels of AST and alkaline phosphatase, indicating liver damage, that appeared within 12 hr of bile duct ligation correlated with the increased superoxide generation.     

Laparoscopic cholecystectomy and lithiasis of the common bile duct: prospective study on the importance of preoperative endoscopic ultrasonography and endoscopic retrograde cholangiography

OBJECTIVES: Laparoscopic cholecystectomy is the standard treatment of symptomatic gallstones. At present, no consensus has been reached on the diagnostic and therapeutic methods of concomitant common bile duct stones. Systematic preoperative endoscopic ultrasonography followed, if necessary, by endoscopic retrograde cholangiography and sphincterotomy during the same anesthetic procedure could be a diagnostic and therapeutic alternative for common bile duct stones making possible a laparoscopic cholecystectomy without intraoperative investigation of the common bile duct. METHODS: One hundred and twenty-five patients underwent a prospective endoscopic ultrasonographic evaluation prior to laparoscopic cholecystectomy for symptomatic gallstones. Fourty-four patients (35%) had at least one predictive factor for common bile duct stones. Endoscopic ultrasonography and cholecystectomy were performed on the same day. Endoscopic ultrasonography was followed by endoscopic retrograde cholangiography and sphincterotomy by the same endoscopist in case of common bile duct stones on endoscopic ultrasonography. Patients were routinely followed up between 3 and 6 months and one year after cholecystectomy. RESULTS: Endoscopic ultrasonography suggested common bile duct stones in 21 patients (17%). Endoscopic ultrasonography identified a stone in 17 of 44 patients (38.6%) with predictor of common bile duct stones and only in 4 of 81 patients (4.9%) without predictor of common bile duct stone. Among these 21 patients, one patient was not investigated with endoscopic retrograde cholangiography because of the high risk of sphincterotomy, 19 patients had a stone removed after sphincterotomy, one patient had no visible stone neither on endoscopic retrograde cholangiography, nor on exploration of the common bile duct after sphincterotomy. Endoscopic ultrasonography was normal in 104 patients (83%). However, two patients in this group were investigated with endoscopic retrograde cholangiography because endoscopic ultrasonography was incomplete in one case and because endoscopic ultrasonography was normal in the second case but a stone in the left hepatic duct was detected by ultrasonography. A stone was removed after endoscopic sphincterotomy in these two patients. In the group of 102 patients without stone, 91 out of 92, continued to be asymptomatic during a median follow-up of 8.5 months. One patient with symptoms one month after cholecystectomy underwent endoscopic sphincterotomy but no stone was found. CONCLUSIONS: Systematic preoperative endoscopic ultrasonography followed, if necessary with endoscopic retrograde cholangiography and sphincterotomy is a diagnostic and therapeutic alternative for common bile duct stones making possible a laparoscopic cholecystectomy without intraoperative investigation of the common bile duct for all patients. This alternative is only justifiable in patients with predictor of common bile duct stones.     

Interobserver variation in the assessment of the sampling quality of cervical smears

The present study was carried out to investigate the biochemical and morphological changes in the liver after ligation of the hepatic artery (HA) in the presence and in the absence of extrahepatic cholestasis (EHC). The study was conducted on 100 rats divided into four groups of 25 animals each: group 1, sham operation; group 2, hepatic artery ligation (HAL); group 3, bile duct ligation (BDL); and group 4, HAL plus BDL. All animals were sacrificed 7 days after surgery when total bilirubin and fractions, alkaline phosphatase (AP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured in serum and on the inner hepatocyte mitochondrial membrane (IHMM); the incidence of necrosis and the volume fractions of vessels, bile ducts and hepatocytes in the liver were also determined. HAL reduces the relative volumes of bile ducts, with no changes in levels of bilirubin and fractions, AP, ALT, AST and IHMM, but HAL associated with EHC reduces duct proliferation and the liver becomes more vulnerable to necrosis. In conclusion, the normal liver depends on HA flow and this dependence is more evident in the presence of EHC.     

Detection of choledocholithiasis: comparison of unenhanced helical CT and endoscopic retrograde cholangiopancreatography

PURPOSE: To compare unenhanced helical computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP) in the detection of common bile duct calculi. MATERIALS AND METHODS: Within 13 months, 51 patients (aged 18-94 years) with clinically suspected choledocholithiasis underwent unenhanced helical CT immediately before undergoing ERCP. CT scans were evaluated for the presence of bile duct stones, ampullary stones, the gallbladder and gallbladder stones, intrahepatic biliary dilatation, and the size of the bile duct at the porta hepatis and in the pancreatic head. ERCP images were evaluated for the presence of bile duct or ampullary stones, as well as for biliary dilatation. RESULTS: Unenhanced helical CT depicted common bile duct stones in 15 of 17 patients found to have stones at ERCP. Three patients had stones impacted at the ampulla, all of which were detected with CT. In addition, there was one false-positive finding at CT. CT had a sensitivity of 88%, a specificity of 97%, and an accuracy of 94% in the diagnosis of common bile duct stones. CONCLUSION: Unenhanced helical CT is useful for evaluating suspected choledocholithiasis.     

Reversibility of hepatic mitochondrial damage in rats with long-term cholestasis

BACKGROUND/AIMS: Long-term bile duct ligation in rats is associated with secondary biliary cirrhosis and metabolic alterations, e.g. mitochondrial dysfunction. We performed the current studies to characterize the reversibility of hepatic mitochondrial dysfunction after reversing biliary obstruction by Roux-en-Y anastomosis. METHODS: Rats were studied after 4 weeks of bile duct ligation, and after 5 or 14 days of reanastomosis. Control rats were pair-fed to treated rats and all rats were studied after starvation for 24 h. Mitochondria were isolated by differential centrifugation and enzyme activities determined by spectrophotometric methods. RESULTS: In comparison to controls, plasma beta-hydroxybutyrate concentrations were decreased in bile duct ligated rats (200+/-70 vs. 790+/-200 micromol/l) and remained decreased after relief of biliary obstruction. In contrast, plasma free fatty acids were not different between controls and treated rats. Oxidative metabolism of L-glutamate, succinate and duroquinol was decreased in liver mitochondria from bile duct ligated rats. After relief of biliary obstruction, the metabolism of L-glutamate and duroquinol normalized quickly, whereas succinate metabolism remained impaired. Similar results were obtained for the mitochondrial oxidases in disrupted mitochondria. The activities of complex I, II, III and V of the respiratory chain were reduced in bile duct ligated rats. After relief of biliary obstruction, complex I and III normalized quickly, whereas complex II and V remained impaired. Oxidative metabolism of long-chain fatty acids by isolated liver mitochondria was decreased in bile duct ligated rats and did not recover after relief of biliary obstruction. CONCLUSIONS: Long-term cholestasis in the rat is associated with a decrease in specific functions of liver mitochondria which recover only partially after Roux-en-Y anastomosis. The persistence of decreased mitochondrial fatty acid metabolism cannot be explained by impaired activity of the respiratory chain, but is more likely due to alterations in mitochondrial beta-oxidation.     

Estrogen alleviates cognitive dysfunction following transient brain ischemia in ovariectomized gerbils

Acute hepatic failure models with extensive hepatic necrosis and hyperammonemia were developed in small animals. One model is bases on the retrograde infusion of ethanolamine oleate into the common bile duct of guinea pigs and another is based on the infusion of TNF-lipiodol emulsion into the portal tract of rats.     

Expression of nitric oxide synthase in normal and preeclamptic placental tissue and effects of glyceryl trinitrate and shear stress on placental blood flow

Large and multiple common bile duct stones may defy extraction despite an adequate endoscopic papillotomy. We treated 65 patients with symptomatic bile duct stones with endoscopic stents after failed attempts at stone extraction. Of the 65 patients, bile duct stones were extracted in eight at a second attempt, 29 underwent elective surgery and 28 patients were followed with the stent in situ for 21-52 months (median 42 months). During follow up, two patients had recurrent pain and two required surgery. The remaining 24 patients remained asymptomatic. Biliary stenting is a safe and effective mode of treatment for common bile duct stones in patients who have failed stone extraction after endoscopic papillotomy.     

A microcholangiographic study of liver disease models in rats

RATIONALE AND OBJECTIVES: Rats develop hepatobiliary injury due to small bowel bacterial overgrowth (SBBO) that, at specimen, resembles cholangiography sclerosing cholangitis. To better visualize the smaller bile ducts, we used microcholangiography to determine the spectrum of biliary lesions in this and five other models of liver disease. METHODS: The models studied were as follows: (1) Surgically created jejunal, self-filling blind loops induce SBBO. (2) Intraperitoneal injection of a bacterial cell wall polymer, peptidoglycan-polysaccharide (PG-PS), causes granulomatous hepatitis. (3) Intraperitoneal injection of endotoxin (lipopolysaccharide) causes sinusoidal congestion and shock. (4) Bile duct ligation induces bile duct proliferation. (5) Alpha-naphthyl-isothiocyanate (ANIT) induces bile duct proliferation. (6) Carbon tetrachloride (CCl4) causes fibrosis and cirrhosis. Warmed barium sulfate, gelatin, and saline were injected in the extrahepatic bile duct. Liver slices (2 mm) underwent microradiographic techniques, and images were correlated with histology. RESULTS: Rats with SBBO had irregular and dilated extrahepatic bile ducts with thickened walls. Rats treated with endotoxin and CCl4 had normal microcholangiograms. Bile duct proliferation was identified following ANIT and bile duct ligation. Rats given PG-PS demonstrated irregular intrahepatic bile ducts. Microcholangiograms following SBBO and PG-PS showed similarities including focal ductal dilatation, narrowing, proliferation, and destruction. CONCLUSION: Various models of liver injury induce characteristic cholangiographic appearances. Microcholangiography is useful in examining biliary tract lesions and complements histology.     

Prediction of recurrent choledocholithiasis by quantitative cholescintigraphy in patients after endoscopic sphincterotomy

BACKGROUND: Endoscopic sphincterotomy (EST) is widely used for the removal of stones from the bile duct, but stones recur in about one fifth of patients. AIMS: To investigate hepatic clearance by quantitative cholescintigraphy (QC) in patients after EST and to discern the relationship between biliary emptying and stone recurrence. METHODS: One hundred and forty nine patients who had EST and clearance of the bile duct for choledocholithiasis were selected. All patients were confirmed to have complete EST by sphincter of Oddi manometry and underwent QC soon after normalisation of liver function. Regular clinical follow up was performed for each patient. RESULTS: During a mean 36 month follow up, 22 (14.8%) patients developed recurrent stones in the bile duct. Irrespective of the status of the gall bladder, patients with recurrent stones had a slower hepatic clearance of radioisotope during QC compared with patients without stone recurrence, but only the differences in cholecystectomised patients had statistical significance. After carrying out multivariate analysis, one parameter of QC, percentage clearance of maximal count at 45 minutes, was found to be the only significant factor for stone recurrence. All recurrent stones in the common bile duct were successfully removed at endoscopy. CONCLUSION: Slower hepatic clearance as shown by QC is an important factor responsible for stone recurrence after sphincter ablation.     

Ca(2+)-permeable, outwardly-rectifying K+ channels in mesophyll cells of Arabidopsis thaliana

Advances in cannulation techniques and instruments have helped in difficult bile duct cannulation and thus stone extraction. For small common bile duct (CBD) stones, endoscopic papillary balloon dilatation has been proposed as an alternative to endoscopic papillotomy (EPT). The technique must undergo further evaluation before recommending its routine use. For most patients with bile duct stones, EPT remains the method of choice. Out of 8204 patients treated in three surgical endoscopy centers (Chile, Germany, and India), 86% to 91% of all CBD stones could be extracted subsequently after EPT using a Dormia basket; 4% to 7% required mechanical lithotripsy (ML) before removal and 3% to 10% of the patients needed other sophisticated techniques, such as electrohydraulic lithotripsy (EHL), laser-induced shock-wave lithotripsy (LISL), or extracorporeal shock-wave lithotripsy (ESWL). The local expertise and availability of equipment determines the choice of method used. In general, EHL or LISL is used for impacted CBD stones including stones in Mirizzi syndrome refractory to ML. ESWL is best suited for intrahepatic stones. Permanent stenting can be offered to poor risk patients instead of extensive procedures to clear the bile duct. Using currently available nonsurgical techniques, fewer than 1% of all patients with bile duct stones still require surgical intervention.     

Preoperative diagnosis of laparoscopic cholecystectomy. Is there an indication for routine intravenous cholangiography?

In a retrospective study including 163 patients we investigated the necessity of i.v. cholangiography in preoperative routine diagnostic workup prior to laparoscopic cholecystectomy. We evaluated the evidence of i.v. cholangiography concerning the anatomy of the biliary system, the evidence of common bile duct or cystic duct stones and the influence on the further therapeutic procedure. While the common bile duct could be demonstrated in 96.3%, the cystic duct could be visualized in only 54.6%. One out of two patients with a short cystic duct was identified. Stones in the gallbladder were recognized in 72.4% of cases, while only two out of three patients with common bile duct stones were diagnosed. In nine cases a deep junction of the cystic duct was found, but there was no influence on further operative procedure. Thus we found no improvement after routine use of i.v. cholangiography concerning the evidence of common bile duct stones or avoidance of intraoperative lesions of the common bile duct. The routine use of i.v. cholangiography prior to laparoscopic cholecystectomy is therefore not justified.     

Polyethylene glycol-modified bilirubin oxidase improves hepatic energy charge and urinary prostaglandin levels in rats with obstructive jaundice

BACKGROUNDS/AIMS: No study has so far been conducted to clarify whether the presence of hyperbilirubinemia is detrimental to liver and renal functions. In the present study, the effects of polyethylene glycol-modified bilirubin oxidase (PEG-BOX) therapy on liver and renal function tests, hepatic energy charge and urinary prostaglandin levels were evaluated in a rat model of obstructive jaundice. METHODS: Sprague-Dawley rats were used in the experimental model of obstructive jaundice. PEG-BOX or an equivalent amount of PEG alone was intravenously injected into the animals and sampling of blood and urine, and liver harvesting were done sequentially after bile duct ligation. RESULTS: Conventional liver function tests showed no difference between PEG-BOX and control groups. However, bilirubin concentrations in the peripheral blood and liver tissue specimens markedly decreased, and the hepatic energy charge significantly increased in the PEG-BOX group as compared to controls. The blood concentration of bile acid was lower, but its urinary excretion was higher in the PEG-BOX group than in the control group. In vitro incubation of PEG-BOX with serum from rats with obstructive jaundice decreased the concentration of bilirubin but not that of bile acid. The urinary levels of prostaglandin E2 and the thromboxane B2/6-keto-prostaglandin Fla ratio were significantly lower in the PEG-BOX group than in the control group. CONCLUSIONS: The systemic reduction of bilirubin concentration may contribute to normalization of the urinary levels of prostaglandins and thromboxane B2, to decrease in serum bile acid levels, and to improvement of the hepatic energy charge in obstructive jaundice. These findings suggest that preoperative improvement of jaundice may be beneficial to patients with obstructive jaundice.