UGT1A1 dysfunction increases liver burden and aggravates hepatocyte damage caused by long-term bilirubin metabolism disorder.

UGT1A1 is the only enzyme that can metabolize bilirubin, and its encoding gene is frequently mutated. UGT1A1*6 (G71R) is a common mutant in Asia which leads to the decrease of UGT1A1 activity and abnormal bilirubin metabolism. However, it is not clear whether low UGT1A1 activity-induced bilirubin metabolism disorder increases hepatocyte fragility. ugt1a+/- mice were used to simulate the UGT1A1*6 (G71R) population. Under the same CCl4 induction condition, ugt1a+/- mice showed severer liver damage and fibrosis, indicating that ugt1a1 dysfunction increased liver burden and aggravated hepatocyte damage. In the animal experiment with a continuous intraperitoneal injection of bilirubin, the ugt1a+/- mice livers had more serious unconjugated bilirubin accumulation. The accumulated bilirubin leads to hyperphosphorylation of IκB-α, Ikk-ß, and p65 and a significant increase of inflammatory factor. The α-SMA and Collagen I proteins markedly up-regulated in the ugt1a+/- mice livers. Immunofluorescence and confocal microscopy showed that hepatic stellate cells and Kupffer cells were activated in ugt1a+/- mice. Comprehensive results show that there was a crosstalk relationship between low UGT1A1 activity-bilirubin-liver damage. Furthermore, cell experiments confirmed that unconjugated bilirubin activated the NF-κB pathway and induced DNA damage in hepatocytes, leading to the significant increase of inflammatory factors. UGT1A1 knockdown in hepatocytes aggravated the toxicity of unconjugated bilirubin. Conversely, overexpression of UGT1A1 had a protective effect on hepatocytes. Finally, Schisandrin B, an active ingredient with hepatoprotective effects, extracted from a traditional Chinese medicinal herb, which could protect the liver from bilirubin metabolism disorders caused by ugt1a1 deficiency by downregulating p65 phosphorylation, inhibiting Kupffer cells, reducing inflammation levels. Our data clarified the mechanism of liver vulnerability caused by cross-talk between low UGT1A1 activity bilirubin, and provided a reference for individualized prevention of liver fragility in Gilbert's syndrome.

A Gilbert syndrome-associated haplotype protects against fatty liver disease in humanized transgenic mice.

UDP-glucuronosyltransferases 1 A (UGT1A) enzymes are capable of detoxifying a broad range of endo- and xenobiotic compounds, which contributes to antioxidative effects, modulation of inflammation and cytoprotection. In the presence of low-function genetic UGT1A variants fibrosis development is increased in various diseases. This study aimed to examine the role of common UGT1A polymorphisms in NASH. Therefore, htgUGT1A-WT mice and htgUGT1A-SNP mice (carrying a common human haplotype present in 10% of the white population) were fed a high-fat Paigen diet for 24 weeks. Serum aminotransferase activities, hepatic triglycerides, fibrosis development and UGT1A expression were assessed. Microscopic examination revealed higher hepatic fat deposition and a significant induction of UGT1A gene expression in htgUGT1A-WT mice. In agreement with these observations, lower serum aminotransferase activities and lower expression levels of fibrosis-related genes were measured in htgUGT1A-SNP mice. This was accompanied by reduced PPARα protein levels in htgUGT1A-WT but not in SNP mice. Our data demonstrate a protective effect of a UGT1A SNP haplotype, leading to milder hepatic steatosis and NASH. Higher PPARα protein levels in animals with impaired UGT1A activity are the likely result of reduced glucuronidation of ligands involved in PPARα-mediated fatty acid oxidation and may lead to the observed protection in htgUGT1A-SNP mice.

"Gilbert's-like" syndrome as part of a spectrum of persistent unconjugated hyperbilirubinemia in post-chronic hepatitis patients.

Gilbert's syndrome (GS) patients present with remittent unconjugated hyperbilirubinemia. In this study, we investigated the correlation between polymorphisms in the gene encoding UDP-glucuronosyltransferase, UGT1A1, and the development of unconjugated hyperbilirubinemia in clinical GS and post-hepatitis hyperbilirubinemia. Blood samples were collected from 285 patients, including 85 patients who were clinically diagnosed with GS, 70 patients who had indirect hyperbilirubinemia during the recovery period of chronic liver diseases, 109 patients with normal hepatic function and 21 chronic active hepatitis patients. All samples were tested for the presence of the *28/*6 UGT1A1 genotype by pyrosequencing. Compared with the GS-control group, a significant difference in variations of the UGT1A1*28/*6 allele gene was found in GS patients. The post-hepatitis group showed a significant difference in the UGT1A1*28/*6 allele gene frequency distribution relative to that in the hepatitis control group. There were no significant differences between the GS group and post-hepatitis group in the distribution of the UGT1A1*28/*6 allele gene frequency and UGT1A1 diplotypes. UGT1A1*28/*6 gene polymorphisms in patients who had indirect hyperbilirubinemia while recovering from chronic liver diseases presented similar patterns as those seen for GS patients. These findings suggest that a "Gilbert's-like" syndrome might be part of the spectrum of persistent unconjugated hyperbilirubinemia in post-chronic hepatitis patients.

Differences in UGT1A1 gene mutations and pathological liver changes between Chinese patients with Gilbert syndrome and Crigler-Najjar syndrome type II.

Diagnosis of Crigler-Najjar syndrome type II (CNS-II) and Gilbert syndrome (GS) based on the serum bilirubin concentration is difficult, because this parameter can fluctuate under certain conditions. The aim of this study was to explore differences in UGT1A1 gene mutations, which cause both CNS and GS, and pathological changes between CNS-II and GS.Ninety-five Chinese patients with hereditary unconjugated hyperbilirubinemia were enrolled in this study. Peripheral blood samples obtained from patients were used to evaluate bilirubin levels and for UGT1A1 gene testing. Percutaneous needle biopsy of the liver and staining of tissue samples with hematoxylin and eosin, Masson trichrome, reticulin, and Perl Prussian blue were performed for 59 patients. The Ishak scoring system was used to assess inflammatory activity and the extent of fibrosis.One hundred ninety-two UGT1A1 mutations at 6 sites were detected in the 95 patients; the most common mutation in GS was c.-3279T>G in the phenobarbital response enhancing motif of the UGT1A1 promoter, whereas the most common mutation in CNS-II was p.G71R. The frequency of heterozygous p.G71R mutations in CNS-II was significantly higher than that in GS (P = .001); however, the frequency of homozygous c.-3279T>G mutations in CNS-II was markedly lower than that in GS (P = .032). Among all patients with multiple mutations, the frequency of p.Y486D was significantly higher in CNS-II than in GS (P = .007). The frequency of compound c.-3279T>G, A(TA)7TAA, and p.G71R mutations in CNS-II was significantly higher than that in GS (P = .001). Among the 59 patients who underwent percutaneous needle biopsy, 20 had iron deposition in the liver. The frequency of hepatic iron deposition in CNS-II was significantly higher than that in GS (P = .002).The linked polymorphic mutations, A(TA)7TAA and c.-3279T>G in UGT1A1, were most strongly associated with GS, whereas mutations in the coding region, especially p.G71R and p.Y486D, were more strongly associated with CNS-II. Iron deposition was more common in liver biopsies from patients with CNS-II than in those with GS.

Mildly elevated unconjugated bilirubin is associated with reduced platelet activation-related thrombogenesis and inflammation in Gilbert's syndrome.

Gilbert's syndrome (GS) is associated with a mild unconjugated hyperbilirubinemia, increased circulating antioxidant capacity, and reduced cardiovascular disease (CVD) risk. The current study investigated whether mildly elevated circulating unconjugated bilirubin (UCB) is negatively associated with multiple thrombotic risk factors including platelet activity, hemostatic function, and inflammation in individuals with GS. Blood samples were collected from matched GS and control subjects (14 per group). Activation-dependent platelet surface marker expression of PAC-1 (binds to GPIIb/IIIa surface receptors on activated platelets) and CD62P (marker for P-selectin released from activated degranulated platelets) was assessed in adenosine diphosphate (ADP)-stimulated platelets using flow cytometry. Exogenous agonists, ADP, collagen, and arachidonic acid (AA), were used to stimulate platelet aggregation. A statistically significant decrease in the expression of P-selectin (P = 0.030) on activated platelets was observed in GS subjects. Collagen and AA-induced platelet aggregation were significantly (P = 0.018; P = 0.032 for respective agonists) reduced in GS versus control group. Elevated UCB (P = 0.001) and high density lipoprotein (P = 0.033) in addition to reduced low density lipoprotein (P = 0.024) and high sensitive C-reactive protein (P = 0.043) were also observed in GS when compared to the control group. Reduced P-selectin expression suggests decreased platelet activation-dependent degranulation, while reduced platelet aggregation by AA and collagen indicates a quantitative decrease in platelet aggregation consequently targeting the cyclooxygenase-1 and GP VI pathways, respectively. These findings are the first to demonstrate that the activation of platelets is mildly inhibited in individuals with GS, an effect that might contribute to protection from platelet hyperactivation-induced thrombosis and thus cardiovascular mortality in individuals with benign hyperbilirubinemia.

Features of an altered AMPK metabolic pathway in Gilbert's Syndrome, and its role in metabolic health.

Energy metabolism, involving the ATP-dependent AMPK-PgC-Ppar pathway impacts metabolic health immensely, in that its impairment can lead to obesity, giving rise to disease. Based on observations that individuals with Gilbert's syndrome (GS; UGT1A1(*)28 promoter mutation) are generally lighter, leaner and healthier than controls, specific inter-group differences in the AMPK pathway regulation were explored. Therefore, a case-control study involving 120 fasted, healthy, age- and gender matched subjects with/without GS, was conducted. By utilising intra-cellular flow cytometry (next to assessing AMPKα1 gene expression), levels of functioning proteins (phospho-AMPK α1/α2, PgC 1 α, Ppar α and γ) were measured in PBMCs (peripheral blood mononucleated cells). In GS individuals, rates of phospho-AMPK α1/α2, -Ppar α/γ and of PgC 1α were significantly higher, attesting to a boosted fasting response in this condition. In line with this finding, AMPKα1 gene expression was equal between the groups, possibly stressing the post-translational importance of boosted fasting effects in GS. In reflection of an apparently improved health status, GS individuals had significantly lower BMI, glucose, insulin, C-peptide and triglyceride levels. Herewith, we propose a new theory to explain why individuals having GS are leaner and healthier, and are therefore less likely to contract metabolic diseases or die prematurely thereof.

FEATURES OF GILBERT'S SYNDROME IN PATIENTS WITH DIFFERENT GENOTYPES UGT1AI.

The aim; to evaluate the clinical manifestations and data of instrumental methods in patients with Gilbert's syndrome and different genotype UGT1A1. MATERIALS AND METHODS: Clinical manifestations and results of instrumental methods were studies in 104 patients with Gilbert's syndrome (UGIlAl gene mutation rs8175347), including 75 with the homozygous variant (genotype 7TA*7TA) and 29 - with heterozygous variant (genotypes 6TA*7TA or 6TA*STA). RESULTS: The most frequent clinical manifestation was asthenovegetative syndrome. The promoter of the appearance/intensification ofjaundice were physical activity, stress and viral infections. Homozygotes exhibit an earlier manifestation of the disease, higher rates of bilirubin (sometimes not only due to deconjugating), a greater variety of stigmas undifferentiated dysplasia of connective tissue, more frequent detection of biliary sludge or gallstones. The clinical observation of a family case of Gilbert's syndrome where the mother is a homozygote, and the son - heterozygotes on UGT1A1 mutation is presented, which shows the above differences associated with genotype. CONCLUSION: Patients with asthenic constitution and the stigma dysplasia of connective tissue have to be examined by the presence of mutations rs8175347 gene UGT1A1. The carrier not only homozygous but with the heterozygous variant mutations may require changes in the interpretation of symptoms, lifestyle, medication, etc.

[VISCOELASTISITY AND ELECTRICAL PARAMETERS OF ERYTHROCYTES IN GILBERT SYNDROME].

Results of viscoelastic and electrical properties of erythrocytes study in patients with genetically confirmed Gilbert's syndrome (n = 81) are presented. Dielectrophoresis of erythrocytes in a nonuniform an alterning electric field was performed in81 patients with Gilbert's syndrome and in 20 persons of the comparison group without of the pathology identified by thelaboratory and instrumental examination. The significant differences in viscoelasticity properties of erythrocytes in Gilbert'ssyndrome were obtained. The amplitude of the deformation, the speed of movement to the electrodes and the polarizability on electric field's of all frequencies were significantly lower, but generalized rigidity index, viscosity, index of aggregationand degradation on electric field's of all frequencies were higher than in the comparison group. A number of electricalparameters (conductivity, the capacity of the cells and the relative polarizability) were also higher than in the comparisongroup. Some differences in the parameters of erythrocytes were obtained from homozygous and heterozygous carriers of A(TA), TAA of gene UGT1A1 promotor.

Diagnosis and treatment of a 16-year-old Chinese patient with concurrent hereditary hemochromatosis and Gilbert's syndrome.

Gilbert's syndrome and hereditary hemochromatosis predominantly affect Caucasians with a low incidence in Asians. Here we report the case of a 16-year-old Chinese boy, who was admitted with hepatalgia, jaundice, hyperpigmentation, and splenomegaly to our hospital. After excluding chronic hepatitis, autoimmune disorders, and alcohol or drug injury, genetic analyses of the patient and his parents revealed simultaneous manifestations of Gilbert's syndrome and hereditary hemochromatosis, though his parents did not develop related symptoms. The presented case indicates that diagnoses of Gilbert's syndrome and hereditary hemochromatosis should be taken into consideration when chronic hepatitis is suspected without a clear etiology.

Pyrimidine-5'-nucleotidase Campinas, a new mutation (p.R56G) in the NT5C3 gene associated with pyrimidine-5'-nucleotidase type I deficiency and influence of Gilbert's Syndrome on clinical expression.

Pyrimidine-5'-nucleotidase type I (P5'NI) deficiency is an autosomal recessive condition that causes nonspherocytic hemolytic anemia, characterized by marked basophilic stippling and pyrimidine nucleotide accumulation in erythrocytes. We herein present two African descendant patients, father and daughter, with P5'N deficiency, both born from first cousins. Investigation of the promoter polymorphism of the uridine diphospho glucuronosyl transferase 1A (UGT1A) gene revealed that the father was homozygous for the allele (TA7) and the daughter heterozygous (TA6/TA7). P5'NI gene (NT5C3) gene sequencing revealed a further change in homozygosity at amino acid position 56 (p.R56G), located in a highly conserved region. Both patients developed gallstones; however the father, who had undergone surgery for the removal of stones, had extremely severe intrahepatic cholestasis and, liver biopsy revealed fibrosis and siderosis grade III, leading us to believe that the homozygosity of the UGT1A polymorphism was responsible for the more severe clinical features in the father. Moreover, our results show how the clinical expression of hemolytic anemia is influenced by epistatic factors and we describe a new mutation in the P5'N gene associated with enzyme deficiency, iron overload, and severe gallstone formation. To our knowledge, this is the first description of P5'N deficiency in South Americans.

[Ultrastructure of hepatocytes in Gilbert's syndrome patients and chronic hepatitis B patients].

OBJECTIVE: To explore the pathological characteristics of inborn hyperbilirubinemia of patients with Gilbert's syndrome (GS). METHODS: Patients with GS (n = 7) and patients with chronic hepatitis B (CHB; n = 8) were enrolled in the study. GS was diagnosed by peripheral blood analysis results showing glucuronyl transferase gene mutation. The histology and ultrastructure of biopsied liver tissues were evaluated by light microscopy and transmission electron microscopy. RESULTS: The GS group showed normal structure in the hepatic portal area and lobule; however, bile pigment granules with high electron density were noted in the hepatocytes. The CHB group showed abnormal structure of the hepatic lobules, including infiltration of inflammatory cells, necrotic regions, degenerated hepatocytes, bile duct injury, and fibrosis in the portal tracts; a few bile pigment granules were observed. The GS group also showed greater quantity and size of bilirubin deposits than the CHB group. CONCLUSION: The histological and ultrastructural features of GS include normal hepatic lobule and deposition of bile pigment granules in hepatocytes.

[Clinical and pathological features of 16 patients with Gilbert syndrome and 2 cases with genetic analysis].

OBJECTIVE: To summarize the clinical and pathological features of Gilbert syndrome. METHODS: The clinical features and liver histological findings of 16 cases of Gilbert syndrome were reviewed. RESULTS: Of the 16 cases (13 males and 3 females, with an age range from 14 to 40 years), all had recurrent jaundice, unconjugated hyperbilirubinemia and lipofuscin granules in the hepatocytes around the hepatic perivenular areas. The genetic analysis of the two patients showed that the site of genetic mutations were located at exon 1 (Gly71Arg). CONCLUSIONS: The diagnosis of Gilbert disease can be improved by combining the data of clinical features, the genetic analysis findings and the histological changes of the livers of the patients.

Trastornos delirante somatomorfo corporal asociado a enfermedad de Gilbert / Corporal somatomorphic delirious disorder associated to Gilbert's disease

El caso en cuestión tiene como importancia que se asocia por primera vez la presencia de un trastorno delirante tipo somático (dismorfofobia corporal) a una afección llamada enfermedad de Gilbert (hiperbilirrubinemia congénita o adquirida), que se caracteriza por un déficit congénito de la enzima glucoronil-transferasa que conjuga la bilirrubina indirecta en directa a nivel hepático, por lo tanto dicho déficit aumenta los niveles en sangre de la bilirrubina indirecta, lo que provoca la aparición de un discreto tinte subictérico en la piel y mucosas. Cuando este déficit enzimático es congénito se llama enfermedad de Gilbert y cuando es posterior a un daño hepático, por ejemplo, hepatitis viral tipo A, entonces se llama síndrome de Gilbert.

This case is relevant because for the first time a somatic delirious disorder (corporal dismorphophobia) is associated to Gilbert’s disease (congenital or acquired hyperbilirrubinemia), which is characterized by a congenital deficit of glucoronil – transferase enzyme that conjugates indirect bilirrubine in direct bilirrubine at hepatic level, due to this, such a deficit increases the indirect bilirrubine blood levels and this produces a mild subicteric color on the skin and mucosa. When this enzymatic deficit is congenital it is called Gilbert’s disease, and when it happens after hepatic damages, for instance viral hepatitis type A, it is called Gilbert’s syndrome.

Trastornos delirante somatomorfo corporal asociado a enfermedad de Gilbert / Corporal somatomorphic delirious disorder associated to Gilbert's disease

El caso en cuestión tiene como importancia que se asocia por primera vez la presencia de un trastorno delirante tipo somático (dismorfofobia corporal) a una afección llamada enfermedad de Gilbert (hiperbilirrubinemia congénita o adquirida), que se caracteriza por un déficit congénito de la enzima glucoronil-transferasa que conjuga la bilirrubina indirecta en directa a nivel hepático, por lo tanto dicho déficit aumenta los niveles en sangre de la bilirrubina indirecta, lo que provoca la aparición de un discreto tinte subictérico en la piel y mucosas. Cuando este déficit enzimático es congénito se llama enfermedad de Gilbert y cuando es posterior a un daño hepático, por ejemplo, hepatitis viral tipo A, entonces se llama síndrome de Gilbert(AU)

This case is relevant because for the first time a somatic delirious disorder (corporal dismorphophobia) is associated to Gilberts disease (congenital or acquired hyperbilirrubinemia), which is characterized by a congenital deficit of glucoronil transferase enzyme that conjugates indirect bilirrubine in direct bilirrubine at hepatic level, due to this, such a deficit increases the indirect bilirrubine blood levels and this produces a mild subicteric color on the skin and mucosa. When this enzymatic deficit is congenital it is called Gilberts disease, and when it happens after hepatic damages, for instance viral hepatitis type A, it is called Gilberts syndrome(AU)

Gilbert's syndrome: an overview for clinical biochemists.

Gilbert's syndrome (GS) is a benign and inherited state characterized by mild, lifelong, unconjugated hyperbilirubinaemia in the absence of haemolysis or evidence of liver disease. Its molecular basis, mutations in the TATA box upstream of the uridine diphosphoglucose glucuronyltransferase gene, leads to impaired bilirubin glucuronidation. This synopsis outlines the pathophysiology and investigation appropriate for this innocent anomaly.

The inverse association of elevated serum bilirubin levels with subclinical carotid atherosclerosis.

BACKGROUND: Serum bilirubin is negatively associated with the development of coronary heart disease. In the present study, we have focused on the analysis of intima-media thickness (IMT) of the common carotid artery in hyper- and normobilirubinemic subjects. METHODS: The study was performed on 111 men without manifested atherosclerosis. In all subjects, complete biochemical tests were determined along with the examination of IMT by carotid ultrasound. RESULTS: The mean IMT in hyperbilirubinemic subjects as compared with controls was substantially lower (p=0.017), and hyperbilirubinemic men also had very low age-adjusted prevalence odds ratios for having IMT above the 50th percentiles of controls, even after adjustment for selected vascular risk factors (p=0.034). CONCLUSIONS: In the present study, we demonstrate the inverse relationship between serum bilirubin and IMT in healthy men.

Successful treatment of severe unconjugated hyperbilirubinemia via induction of UGT1A1 by rifampicin.

We report two patients with uncommon Gilbert's syndrome with severe unconjugated hyperbilirubinemia which was reduced from 200 to 60-90 micromol/L by long-term administration of rifampicin. Hepatic induction of bilirubin-glucuronosyltransferase was suggested by increased relative amounts of conjugated serum bilirubin. This molecular mechanism was confirmed in primary cultures of human hepatocytes.

Proton magnetic resonance spectroscopy of the anterior cingulate gyrus, insular cortex and thalamus in schizophrenia associated with idiopathic unconjugated hyperbilirubinemia (Gilbert's syndrome).

OBJECTIVE: To examine whether patients with schizophrenia associated with idiopathic unconjugated hyperbilirubinemia (Gilbert's syndrome [GS]) have specific changes in brain metabolism. METHODS: We applied proton magnetic resonance spectroscopy (H-MRS) to the anterior cingulate gyrus, insular cortex and thalamus of patients with schizophrenia and GS (n = 15) or without GS (n = 15), all diagnosed with schizophrenia according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), and healthy subjects (n = 20). RESULTS: In the anterior cingulate gyrus, patients with schizophrenia and GS showed significant decreases in N-acetyl aspartate/creatine-phosphocreatinine (NAA/Cr), choline/creatine-phosphocreatinine (Cho/Cr) and myoinositol/creatine-phosphocreatinine (ml/Cr) ratios compared with healthy subjects and compared with patients with schizophrenia without GS. Patients with schizophrenia without GS also showed significant decreases in NAA/Cr, Cho/Cr and ml/Cr compared with healthy subjects. In the insular cortex, patients with schizophrenia and GS showed significant decreases in NAA/Cr, Cho/Cr and ml/Cr compared with healthy subjects and compared with patients with schizophrenia without GS. Patients with schizophrenia without GS also showed significant decreases in NAA/Cr, Cho/Cr and ml/Cr compared with healthy subjects. In the thalamus, patients with schizophrenia and GS showed significant decreases in NAA/Cr, Cho/Cr and ml/Cr compared with healthy subjects, whereas patients with schizophrenia without GS only showed a significant decrease in ml/Cr compared with healthy subjects. CONCLUSIONS: Our findings suggest that brain metabolism is more severely compromised in the subtype of schizophrenia with GS.