Glucuronidation of bilirubin and the occurrence of pigment gallstones in patients with chronic haemolytic diseases

Cholelithiasis in thalassemia major

OBJECTIVES

Aim of this study was to evaluate prevalence and characteristics of cholelithiasis in a large population of patients with thalassemia major (TM).

METHODS

Data from 858 consecutive patients with transfusion-dependent thalassemia at five major Italian centers were analyzed. In these centers, a complete abdomen ultrasonography is performed yearly after the beginning of the transfusion regimen. The role of co-inheriting Gilbert's syndrome genotype was investigated studying the promoter region of the UGT1-A1 gene by automated sequencing.

RESULTS

Thirty percent of TM patients had gallstones. The Gilbert's genotype [homozygosity for (TA)(7) motif at UGT1A promoter gene], influenced both the prevalence of cholelithiasis and the age at which it developed.

CONCLUSIONS

Cholelithiasis has a remarkable frequency and precocity in patients with TM and especially in those with (TA)(7)/(TA)(7) UGT1-A1 genotype. An early biliary ultrasonography is recommended from childhood and a closer follow-up in patients with thalassemia and associated Gilbert's syndrome may be indicated.

Bilirubin in clinical practice: a review

Bilirubin is an endogenous compound that can be toxic under certain conditions but, on the other hand, mild unconjugated hyperbilirubinaemia might protect against cardiovascular diseases and tumour development. Serum bilirubin levels are often enhanced under a variety of clinical conditions. These are discussed and the mechanisms are outlined.

Changes in the liver function tests during the attacks of familial Mediterranean fever

The present study aims to investigate whether or not FMF patients display abnormal liver functions during attack periods. About 41 consecutive FMF patients with attacks were enrolled on this study. Bilirubin levels, liver transaminases, erythrocyte sedimentation rate and C-reactive protein (C-RP) levels were determined within the first 72 h after the onset of attacks. This procedure could be performed on only 28 of these 41 FMF patients, 4 weeks after the attack of the patients' had completely disappeared. As for the disease control group, 44 patients were determined to be eligible for the study. Another 31 healthy individuals were also included. Hyperbilirubinemia was determined in 11 of the 41 patients (26.8%) with FMF. The number of FMF patients with hyperbilirubinemia was significantly higher than in DC and HC (P < 0.001, P = 0.03, respectively). Levels of liver transaminases slightly increased in four patients with FMF during the attack and two of these four patients had also mild hyperbilirubinemia. A significant correlation was found between C-RP levels and total and unconjugated bilirubin levels in FMF patients with attack (r = 0.43, P = 0.01; r = 0.40, P = 0.02, respectively). In conclusion, mild hyperbilirubinemia may occur in one-fourth of the patients with FMF during the attack period.

The influence of uridine diphosphate glucuronosyl transferase 1A promoter polymorphisms, beta-globin gene haplotype, co-inherited alpha-thalassemia trait and Hb F on steady-state serum bilirubin levels in sickle cell anemia

PURPOSE

Homozygosity for the (AT)7 allele of uridine diphosphate glucuronosyl transferase 1A (UGT1A1) gene polymorphism is associated with increased bilirubin levels in sickle cell anemia (SCA). In the present study, in addition to UGT1A1 promoter genotype, serum bilirubin level was related to other genetic modifiers -beta(S)-globin gene haplotype, Hb F, co-inherited alpha-thal trait, age and gender.

METHODS

The patients were randomly selected from the sickle cell clinic, Medical College of Georgia. UGT1A1 promoter polymorphisms were determined using automated sequencing. Other investigations were with standard techniques.

RESULTS

There were 67 SCA patients (41 males and 26 females), aged 2-44 yr (mean of 20.6 +/- 10.7). Ten (14.9%) patients were homozygous for the (AT)6 UGT1A1 allele, 35 (52.2%) were heterozygous for (AT)6 and (AT)7 alleles while 22 (32.8%) were homozygous for (AT)7. Serum bilirubin was significantly higher in the homozygous (AT)7 group (3.7 +/- 1.5, 3.8 +/- 2.3 and 5.6 +/- 2.4 mg/dL, respectively). It was also significantly higher in males than females and in patients aged >10 yr. There was a significant negative linear correlation (r = -0.304, P = 0.016) of serum bilirubin with Hb F. The beta-globin haplotype and co-existing alpha-thal trait did not have any significant influence on serum bilirubin levels. Patients on hydroxyurea were older, had lower Hb F, but higher mean serum bilirubin. The latter also was signifcantly higher among those with UGT1A1 (AT)7 homozygosity.

CONCLUSIONS

Apart from UGT1A1 (AT)7 homozygosity, Hb F, age and gender are the other factors that significantly influence serum bilirubin level in SCA.

Impaired gallbladder motility and delayed orocecal transit contribute to pigment gallstone and biliary sludge formation in β -thalassemia major adults

AIM: Gallbladder and gastrointestinal motility defects exist in gallstones patients and to a lesser extent in pigment gallstone patients. To investigated the role of gallbladder and gastrointestinal motility disorders in pigment gallstone formation in β -thalassemia major.

METHODS: Twenty-three patients with β -thalassemia major (16 females; age range 18-37 years) and 70 controls (47 females, age range 18-40 years) were studied for gallbladder and gastric emptying (functional ultrasonography), orocecal transit (OCTT, H₂-breath test), autonomic dysfunction (sweat-spot, cardiorespiratory reflex tests), bowel habits, gastrointestinal symptoms and quality of life (all with questionnaires). Gallbladder content (ultrasonography) was examined before and during 8-12 mo follow-up.

RESULTS: Gallstones and/or biliary sludge were found in 13 (56%) patients. β -thalassemia major patients had increased fasting (38.0 ± 4.8 mL vs 20.3 ± 0.7 mL, P = 0.0001) and residual (7.9 ± 1.3 mL vs 5.1 ± 0.3 mL, P = 0.002) volume and slightly slower emptying (24.9 ± 1.7 min vs 20.1 ± 0.7 min, P = 0.04) of the gallbladder, together with longer OCTT (132.2 ± 7.8 min vs 99.7 ± 2.3 min, P = 0.00003) than controls. No differences in gastric emptying and bowel habits were found. Also, patients had higher dyspepsia (score: 6.7 ± 1.2 vs 4.9 ± 0.2, P = 0.027), greater appetite (P = 0.000004) and lower health perception (P = 0.00002) than controls. Autonomic dysfunction was diagnosed in 52% of patients (positive tests: 76.2% and 66.7% for parasympathetic and sympathetic involvement, respectively). Patients developing sludge during follow-up (38%, 2 with prior stones) had increased fasting and residual gallbladder volume.

CONCLUSION: Adult β -thalassemia major patients have gallbladder dysmotility associated with delayed small intestinal transit and autonomic dysfunction. These abnormalities apparently contribute together with haemolytic hyperbilirubinemia to the pathogenesis of pigment gallstones/ sludge in β -thalassemia major.

UGT1A promoter polymorphisms influence bilirubin response to hydroxyurea therapy in sickle cell anemia

Hydroxyurea therapy reduces hemolysis and decreases serum bilirubin levels in children and adults with sickle cell anemia (SCA) and may therefore help prevent the development of cholelithiasis in this patient population. We recently reported that a promoter polymorphism in the uridine diphosphoglucuronate glucuronosyltransferase 1A (UGT1A) gene affects steady-state bilirubin levels and the incidence of gallstones in children with SCA. We have now analyzed the influence of the UGT1A genotype on the therapeutic response to hydroxyurea. A large cohort of children with SCA taking hydroxyurea therapy at the maximum tolerated dose demonstrated significant reductions in hemolysis independent of UGT1A promoter polymorphism genotype, but the hydroxyurea-related decreases in serum bilirubin levels were significantly different. Children with the wild-type 6/6 UGT1A genotype demonstrated normalized bilirubin levels with hydroxyurea therapy, but children with the heterozygous 6/7 or abnormal 7/7 genotypes did not. Children with the abnormal 7/7 genotype, which confers the phenotype of Gilbert syndrome, had bilirubin levels greater than 3 mg/dL despite full-dose hydroxyurea therapy. These data indicate the UGT1A promoter polymorphism is a powerful nonglobin genetic modifier in SCA that influences serum bilirubin both at baseline and on hydroxyurea therapy. UGT1A promoter polymorphisms may therefore influence the ability of hydroxyurea to prevent gallstone formation in patients with SCA.

Development of black gallstones after the nonsurgical management of splenic injury: report of a case

A 22-year-old man was admitted to our Emergency Department after suffering splenic injury in a traffic accident. His intraabdominal bleeding was treated nonsurgically by the administration of total parenteral nutrition (TPN) and blood transfusions of packed red cells. He presented again 2 months after his discharge, being 3 months after the injury, for right hypochondralgia, at which time a gallstone was demonstrated on ultrasound (US) and computed tomography (CT). After endoscopic laparoscopic cholecystectomy, his symptoms disappeared and he has remained well since. The clinical course of this patient indicates that hemolytic hyperbilirubinemia can cause black gallstones as a late complication of the nonsurgical management of abdominal blunt trauma.

Coinheritance of Gilbert Syndrome Increases the Risk for Developing Gallstones in Patients With Hereditary Spherocytosis

The precocious formation of bilirubinate gallstones is the most common complication of hereditary spherocytosis (HS), and the prevention of this problem represents a major impetus for splenectomy in many patients with compensated hemolysis. Because Gilbert syndrome has been considered a risk factor for gallstone formation, there are reasons for postulating that the association of this common inherited disorder of hepatic bilirubin metabolism with HS could increase cholelithiasis. To test this hypothesis, 103 children with mild to moderate HS who, from age 1, have undergone a liver and biliary tree ultrasonography every year, were retrospectively examined. The 2-bp (TA) insertion within the promoter of the uridine diphosphate-glucuronosyltransferase gene (UGT1A1), associated with Gilbert syndrome, was screened. The risk of developing gallstones was statistically different among the 3 groups of patients: homozygotes for the normal UGT1A1 allele, heterozygotes, and homozygotes for the allele with the TA insertion. Fitting a Cox regression model, in fact, a statistically significant hazard ratio of 2.19 (95% confidence interval: 1.31 to 3.66) was estimated from one to the next of these genetic classes. The individual proneness to form gallstones from TA insertion in the TATA-box of the UGT1A1 promoter should be considered during the follow-up of patients with HS. Although patients with HS were the only ones studied, extrapolating these data to patients who have different forms of inherited (eg, thalassemia, intraerythrocytic enzymatic deficiency) or acquired (eg, autoimmune hemolytic anemia, hemolysis from mechanical heart valve replacement) chronic hemolysis can be warranted.

Prophylactic splenectomy and cholecystectomy in mild hereditary spherocytosis: analyzing the decision in different clinical scenarios

OBJECTIVES

Patients with mild hereditary spherocytosis (HS), i.e. with haemolysis without anaemia. have an increased risk of gallstone formation, erythroid aplasia and haemolytic crisis. Since the effect of prophylactic splenectomy on life expectancy has not been established, we conducted a decision analysis comparing prophylactic splenectomy and cholecystectomy with no surgery.

DESIGN

The available data on surgery and disease outcomes were modelled to estimate the effects of the different interventions on the quality-adjusted life expectancy. The early phase outcomes depicted surgery-related mortality and incorporated compliance and the adverse effects of prophylaxis against post splenectomy infections. The late phase outcomes were framed by a Markov cohort analysis.

RESULTS

For patients without gallstones, surgery was of no benefit. For those with gallstones the preferred strategies were found to be splenectomy and cholecystectomy before the age of 39 when asymptomatic, and before 52 when accompanied by occasional biliary colic. Cholecystectomy alone proved to be the preferred strategy in older patients with occasional biliary colic. For patients of up to 52 years of age and candidates for cholecystectomy because of recurrent biliary colic, the best strategy was to combine this procedure with splenectomy. Sensitivity analysis showed that the results were sensitive to the incidence of post cholecystectomy syndrome. Most remarkably an extreme sensitivity to compliance with post splenectomy infection prophylaxis was demonstrated.

CONCLUSIONS

Our model suggested that combined prophylactic splenectomy and cholecystectomy provide a substantial gain in quality-adjusted life expectancy for young patients and adults with mild HS and gallstones.

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.

Liver microsomal phospholipid fatty acids behavior and its relationship to bilirubin UDP-glucuronyltransferase activity in bile duct ligated rats

Phospholipid fatty acid composition and bilirubin UDP-glucuronyltransferase activity from liver microsomal membrane were studied in normal and in bile duct ligated rats. Incubation of normal microsomes with 15 microM bilirubin (considered as physiological concentration) yielded 60% bilirubin diglucuronide; in 2 days post-cholestatic rats, they showed 20% bilirubin diglucuronide which was undetectable in 8 days post-cholestatic group. When compared to controls, after 2 days of cholestasis, microsomal phospholipids showed a clear decrease in linoleic and arachidonic acids and an increment in palmitic and stearic acids. 8 days post-cholestatic rats presented a marked increase in palmitic, oleic and docosaexaenoic acids, while linoleic and arachidonic acids decreased. Cholestasis produced disturbances in microsomal phospholipids fatty acid composition; but these changes are unable to explain entirely the severe damage observed in bilirubin diglucuronide formation.

Serum bilirubin fractions in healthy subjects and patients with unconjugated hyperbilirubinemia

Serum bilirubin fractions were determined by a newly developed, high performance liquid chromatography method in 23 healthy subjects, and in 15 patients with Gilbert's syndrome, five with type 2 Crigler-Najjar syndrome, seven with hemolytic disorders, and 26 with neonatal jaundice. In the healthy subjects, 92.6% of the bilirubin was unconjugated (UCB), 6.2% was bilirubin monoglucoronide (BMG), and 0.5% was bilirubin diglucuronide (BDG). Delta bilirubin (B delta) was not detected. In the patients, the percentage of UCB was significantly higher and that of BMG was significantly lower than in the healthy subjects. The proportion of BDG tended to decrease in Gilbert's and type 2 Crigler-Najjar syndromes; the proportion of B delta tended to increase in hyperbilirubinemia, except in Gilbert's syndrome. In particular, B delta was frequently detected in serum which also contained BDG (mainly in hemolytic disorders) or which presented with high concentrations (above 100 mumol/L) of UCB (mainly in type 2 Crigler-Najjar syndrome and neonatal jaundice). Trace amounts of (Z,E)- and/or (E,Z)-UCB were detected in approximately one fourth of the serum samples analyzed.

Glucuronyl transferase deficiency and mild hereditary spherocytosis: effect of splenectomy

In a 6-year-old girl an association of hereditary spherocytosis and a defect in hepatic bilirubin metabolism has been found. The patient suffered from mild compensated haemolytic anaemia and excessive hyperbilirubinaemia (maximum concentration 581 mumol/l), the serum activity of liver enzymes was slightly increased. Examination of the erythrocyte membrane proteins revealed a deficiency of the major membrane skeletal protein, spectrin (about 75% of normal) which is probably the basic genetic defect of hereditary spherocytosis. Examination of the patient's family revealed a recessive mode of inheritance. The concentration of bilirubin conjugates in the patient's serum was decreased due to a reduced UDP-glucuronyl transferase activity found in homogenates of liver tissue. Histological liver examination showed an intrahepatic cholestasis, which is a secondary and reversible alteration resulting from severe hyperbilirubinaemia. After splenectomy, normalization of the increased haemolysis and hepatic dysfunction was observed. The excessive hyperbilirubinaemia can be explained by the association of an increased bilirubin load due to haemolytic anaemia and the diminished hepatic conjugation of bilirubin.

Liver microsomal bilirubin UDP-glucuronyltransferase disturbances in bile duct ligated rats

The activity of bilirubin UDP-Glucuronyltransferase was determined in microsomes from normal and bile duct ligated rats. It was measured after 2 and 8 days following bile duct ligation and compared with normal rats. A decrease of 33% in the total enzyme activity was observed on day 2; a fall of 70% was founded on day 8. Bilirubin diglucuronide represented approximately 20% of total conjugates in both groups of cholestatic rats, as compared with 65% found in normals. It was concluded that bilirubin microsomal conjugating capacity is markedly altered during cholestasis. This can be attributed to microsomal membrane damage produced by stagnant bile.

Effect of cimetidine on the metabolism of cholephilic dyes in Gilbert's syndrome

The metabolism of indocyanine green, bromsulphophthalein and bilirubin was studied before and after a treatment for 2 weeks with cimetidine 1.0 g/day in 12 subjects with Gilbert's syndrome. There was no effect on the plasma clearance of indocyanine green and bromsulphophthalein, on the maximal biliary excretion capacity of bromsulphophthalein, on serum bilirubin concentrations or on the biliary metabolites of bromsulphophthalein and bilirubin. It is concluded that in Gilbert's syndrome two weeks of treatment with cimetidine had no effect on liver blood flow or on conjugation mechanisms which were independent of cytochrome P450.

Effect of phenobarbital on serum and biliary parameters in a patient with Crigler-Najjar syndrome, type II and acquired cholestasis

The effect of phenobarbital treatment on bilirubin metabolism and bile secretion was studied in a patient with Crigler-Najjar syndrome, type II and acquired cholestasis. Following cholecystectomy and choledochostomy, a balloon inflatable T tube was inserted to facilitate bile collection. Hepatic UDP-glucuronyltransferase in surgically obtained liver tissue was 25% of normal activity and bilirubin monoconjugates accounted for greater than 80% of the pigments in bile. Phenobarbital therapy decreased the concentration of fasting serum bile acids by 33% and partially reestablished their enterohepatic cycling postprandially. The total fasting serum bilirubin concentration (greater than 90% unconjugated) increased 21% during phenobarbital treatment and was unaffected by caloric intake. Bile flow was increased 2.7 times after phenobarbital treatment. The biliary concentration of total bilirubin was increased 2.4 times, primarily due to monoconjugated bilirubin, which accounted for 91% of the biliary pigments. Bile acid, phospholipid, cholesterol, and calcium concentrations in bile were significantly increased after phenobarbital. The data indicate that even in the presence of cholestasis an underlying deficiency in bilirubin conjugation may be confirmed by biliary pigment analysis.

Comparison of different activators and diazotization procedures in the assay of bilirubin-UDP-glucuronyl transferase activity in rat liver

The activity of bilirubin-UDP-glucuronyl transferase (UDPGT) in rat liver microsomes was assayed in standardized incubation mixtures employing two different procedures to quantitate formation of conjugated bilirubin: solvent extraction and diazotization with sulfanilic acid, or selective coupling with diazotized ethyl anthranilate at pH 2.7. Both of these procedures yielded equivalent UDPGT activities with several different microsomal preparations, averaging, respectively, 385 and 372 microU protein with untreated microsomes, 646 and 608 microU protein following activation with UDP-N-acetylglucosamine (3.07 mmol/l), and 1370 and 1478 microU protein after treatment with digitonin (0.65%). In rats pretreated with phenobarbital (75 mg/kg per 6 days), a 70-90% increase in UDPGT activity was observed with either diazotization procedure, irrespective of whether 'native', UDP-N-acetylglucosamine-or digitonin-activated enzyme was employed. These studies indicate that, when other conditions are standardized, equivalent information about UDPGT can be obtained with either of two widely employed diazotization reactions and a variety of enzyme activation procedures.

Analysis of bilirubins in biological fluids by extraction and thin-layer chromatography of the intact tetrapyrroles: application to bile of patients with Gilbert's syndrome, hemolysis, or cholelithiasis

A method was developed to extract quantitatively the bilirubins from bile, urine, serum, stool, and preparations from liver with a chloroform-ethanol mixture at pH 1.8 in the presence of ascorbic acid and NaCl. Extracted pigment was submitted to thin-layer chromatography, and the separated bilirubins were either immediately eluted and determined spectrophotometrically or individually converted to ethyl anthranilate azo derivatives for thin-layer chromatographic analysis of each isolated pigment band. Bilirubins in duodenal bile of eight healthy adults comprised 1.5 +/- 1.3% unconjugated bilirubin-IX alpha, 69 +/- 6% bilirubin diglucuronide, and 16 +/- 4% bilirubin monoglucuronides. Mixed diconjugates containing one glucuronosyl moiety and either one xylosyl or one glucosyl group amounted to 10 +/- 3%. Most samples (6 of 8) contained trace amounts (0.6 +/- 0.6%) of unconjugated bilirubin-IX beta, in agreement with nearly exclusive cleavage of heme at the alpha-meso position. The composition of the bilirubins in bile was normal in 6 patients with cholesterol gallstones, 4 with chronic hepatitis, and 3 with hemolysis. In duodenal bile of individuals with Gilbert's syndrome (n = 10), the concentration of bilirubin conjugates was comparable to that in healthy adults, but the proportion of bilirubin diglucuronides (52 +/- 8%) was decreased. The concentration of unconjugated bilirubin-IX alpha showed a fair positive correlation with that of bilirubin monoglucuronide and was increased in half of the patients with Gilbert's syndrome.