How dangerous Gilbert's syndrome is

Gilbert's syndrome is a benign (functional) hyperbilirubinemia, which is based on a hereditary disorder of bilirubin metabolism, as a result of which the concentration of unbound bilirubin can increase several times. Bilirubin, being a breakdown product of hemoglobin, circulates through the bloodstream, combining with albumin molecules. Such bilirubin is called indirect. In the endoplasmic reticulum, it is conjugated; the enzyme glucuronyltransferase is responsible for this process. In Gilbert's syndrome, as a result of insufficient production of this enzyme, the conjugation process is disrupted, and, as a result, the concentration of unconjugated bilirubin increases. According to statistics, this pathological condition is observed in about 5 % of Russians. This syndrome was first described in 1901 by the French physician Augustin Nicolas Gilbert, and was subsequently named after him. The literature also contains references to this syndrome, described as «constitutional hepatic dysfunction», «familial non-hemolytic hyperbilirubinemia», «idiopathic non-conjugated hyperbilirubinemia». Gilbert's syndrome is inherited in an autosomal recessive manner; men get ill 3–4 times more often than women. A number of scientists associate this with a possible inhibitory effect of testosterone on the enzyme UDP-GT1, which breaks down bilirubin. Clinically, Gilbert's syndrome is manifested by episodes of jaundice caused by an increase in the level of unconjugated bilirubin in the blood serum. Against the background of icterus of the sclera and skin, there is increased fatigue, the appearance of a feeling of bitterness in the mouth, loss of appetite, nausea, and sometimes vomiting. The association of Gilbert's syndrome with functional disorders of the biliary tract, in particular, with gallbladder dyskinesia, is often noted.

Hyperbilirubinemia Maintained by Chronic Supplementation of Unconjugated Bilirubin Improves the Clinical Course of Experimental Autoimmune Arthritis

Rheumatoid arthritis (RA) is a chronic multisystem disease, therapy of which remains a challenge for basic research. The present work examined the effect of unconjugated bilirubin (UCB) administration in adjuvant-induced arthritis (AIA)—an experimental model, in which oxidative stress (OS), inflammation and inadequate immune response are often similar to RA. Male Lewis rats were randomized into groups: CO—control, AIA—untreated adjuvant-induced arthritis, AIA-BIL—adjuvant-induced arthritis administrated UCB, CO-BIL—control with administrated UCB. UCB was administered intraperitoneally 200 mg/kg of body weight daily from 14th day of the experiment, when clinical signs of the disease are fully manifested, to 28th day, the end of the experiment. AIA was induced by a single intradermal immunization at the base of the tail with suspension of Mycobacterium butyricum in incomplete Freund’s adjuvant. Clinical, hematologic, biochemical and histologic examinations were performed. UCB administration to animals with AIA lead to a significant decrease in hind paws volume, plasma levels of C-reactive protein (CRP) and ceruloplasmin, drop of leukocytes, lymphocytes, erythrocytes, hemoglobin and an increase in platelet count. UCB administration caused significantly lowered oxidative damage to DNA in arthritic animals, whereas in healthy controls it induced considerable oxidative damage to DNA. UCB administration also induced atrophy of the spleen and thymus in AIA and CO animals comparing to untreated animals. Histological signs of joint damage assessed by neutrophils infiltration and deposition of fibrin were significantly reduced by UCB administration. The effects of exogenously administered UCB to the animals with adjuvant-induced arthritis might be identified as therapeutic, in contrast to the effects of UCB administration in healthy animals rather classified as toxic.

Gilbert Syndrome

Gilbert's syndrome (GS) is a benign condition that does not progress to chronic liver disease or fibrosis. GS diagnosis should be considered in patients with chronic elevation of unconjugated bilirubin. In these patients the presence of hemolysis and other diseases of the liver should be excluded.

Neonatal Hyperbilirubinemia, Types, Causes and Treatments: A Review Study

Neonatal hyperbilirubinemia results from a readiness for the bilirubin production in neonates and limited their ability to excrete it. The diagnosis of hyperbilirubinemia based on yellow discoloration of the skin and whiteness of eyes, idle in the child's movement and the lack of lactation. The baby seems sick or is difficult to awaken. Bilirubin is a tetrapyrrole pigment derived from breakdown product of normal heme catabolism in senescent red blood cells. Unconjugated bilirubin normal elevation is named newborn physiologic hyperbilirubinemia, whereas the level of bilirubin of infant normally to be a bit higher after birth, In the same context the placenta in the womb of the mother. Pathologic hyperbilirubinemia is defined as odd of bilirubin from the normal level so intervention required. Many reasons for this type of jaundice

Physico-chemical characterization of bilirubin-10-sulfonate and comparison of its acid–base behavior with unconjugated bilirubin

Unconjugated bilirubin (UCB) is the end-product of heme catabolism in the intravascular compartment. Although beneficial for human health when mildly elevated in the body, when present at greater than a critical threshold concentration, UCB exerts toxic effects that are related to its physico-chemical properties, particularly affecting the central nervous system. The aim of the present study was to characterize bilirubin-10-sulfonate (ranarubin), a naturally occurring bile pigment, including determination of its mixed acidity constants (pKa*). Thanks to the presence of the sulfonic acid moiety, this compound is more polar compared to UCB, which might theoretically solve the problem with an accurate determination of the UCB pKa* values of its propionic acid carboxylic groups. Bilirubin-10-sulfonate was synthesized by modification of a previously described procedure; and its properties were studied by mass spectrometry (MS), nuclear magnetic resonance (NMR), infrared (IR), and circular dichroism (CD) spectroscopy. Determination of pKa* values of bilirubin-10-sulfonate and UCB was performed by capillary electrophoresis with low pigment concentrations in polar buffers. The identity of the synthesized bilirubin-10-sulfonate was confirmed by MS, and the pigment was further characterized by NMR, IR, and CD spectroscopy. The pKa values of carboxylic acid moieties of bilirubin-10-sulfonate were determined to be 5.02, whereas those of UCB were determined to be 9.01. The physico-chemical properties of bilirubin-10-sulfonate were partially characterized with low pKa* values compared to those of UCB, indicating that bilirubin-10-sulfonate cannot be used as a surrogate pigment for UCB chemical studies. In addition, using a different methodological approach, the pKa* values of UCB were found to be in a mildly alkaline region, confirming the conclusions of a recent critical re-evaluation of this specific issue.

HEREDITARY UNCONJUGATED HYPERBILIRUBINEMIA (COMBINATION OF CRIGLER-NAJJAR SYNDROME TYPE II AND GILBERT'S SYNDROME)

Background. Enzymopathic jaundices are manifested by intermittent hyperbilirubinemia, no changes in the structure of the liver, no hemolysis, Rh-conflict as well as cholestasis being noted. These jaundices include Crigler-Najjar syndrome type I, Crigler-Najjar syndrome type II and Gilbert's syndrome. They are characterized by an autosomal recessive inheritance due to the presence of mutations and polymorphisms in uridine 5'-diphosphate-glucuronosyltransferase gene (UGT1A1) leading to a decrease of the enzyme activity or to its complete loss. Objective. To demonstrate the peculiarities of diagnosis and treatment of a rare case of hereditary unconjugated hyperbilirubinemia - a combination of Crigler-Najjar syndrome type II and Gilbert's syndrome. Material and methods. Clinical observation of a patient G. aged 19, who was examined and treated at the Department of gastroenterology of a multidisciplinary hospital in Moscow in January 2021. Results. The patient G. has had icteric sclerae and skin since birth; he occasionally suffers from easy fatigability and general malaise. Physical examination revealed no changes (except for icteric discoloration). An increase in unconjugated bilirubin up to 270 μmol/L (median - 170 μmol/L) was detected. The molecular genetic study of UGT1A1 gene identified mutations in exon 4 Val378Asp (2002) and Arg108Cys as well as polymorphism 6/7TA in the promoter region, confirming the diagnosis of autosomal recessive inherited disease – a combination of Crigler Najjar syndrome type II and Gilbert's syndrome (heterozygous state), complicated by the development of hepatic encephalopathy stage 2. There was noted a significant decrease in unconjugated bilirubin up to 170.5 μmol/L, as well as improvement in general condition – reduced fatigue and weakness during the treatment with microsomal enzyme inducer (phenobarbital) and hyperammonemia corrector (ornithine aspartate). Conclusions. The use of molecular genetic analysis allows tailoring strategies for patient-specific disease diagnostics, treatment and prevention. The preservation of quality of life within satisfactory level is achieved through elimination of adverse effects provoking the development of this syndrome and through control of risk factors.

Unconjugated Bilirubin Attenuates DSS-Induced Colitis Potentially via Enhancement of Bilirubin Reabsorption

Studies increasingly show that ulcerative colitis (UC) is a consequence of an imbalance between oxidative stress and antioxidant capacity. Bilirubin exerts an anti-inflammatory effect by scavenging reactive oxygen species (ROS), although the exact mechanism is not completely understood. The aim of this study was to determine the role of serum bilirubin in UC using patient data and a mouse model of dextran sodium sulfate (DSS)-induced colitis. We found that low levels of serum bilirubin correlated to a higher risk of UC in a retrospective case-control population. Pre-treatment with exogenous unconjugated bilirubin (UCB) significantly enhanced colonic bilirubin absorption in mice, and attenuated the DSS-induced body weight loss, colon shortening and histopathological damage. Mechanistically, bilirubin prevented the infiltration of inflammatory cells, and decreased the levels of myeloperoxidase and pro-inflammatory cytokines in the serum and colon. Moreover, bilirubin inhibited ROS and malondialdehyde production, scavenged superoxide anions (O2·−) from the colon and enhanced the total antioxidant capacity. In conclusion, exogenous UCB attenuated DSS-induced colitis by directly scavenging O2·− and enhancing bilirubin reabsorption in the colon via enterohepatic cycling.

Neurotoxicity of Unconjugated Bilirubin in Neonatal Hypoxic-Ischemic Brain Injury in vitro

Background: The pathophysiology of bilirubin neurotoxicity in course of hypoxic–ischemic encephalopathy (HIE) in term and preterm infants is still poorly understood. We hypothesized that oxidative stress may be a common mechanism that link hyperbilirubinemia and HIE.Objectives: The objective of the present study was to evaluate whether unconjugated bilirubin (UCB) may enhance the HI brain injury by increasing oxidative stress and to test pioglitazone and allopurinol as new antioxidant therapeutic drugs in vitro.Methods: The effects of UCB were tested on organotypic hippocampal slices subjected to 30 min oxygen-glucose deprivation (OGD), used as in vitro model of HIE. The experiments were performed on mature (14 days in culture) and immature (7 days in culture) slices, to mimic the brains of term and preterm infants, respectively. Mature and immature slices were exposed to UCB, human serum albumin (HSA), pioglitazone, and/or allopurinol for 24 h, immediately after 30 min OGD. Neuronal injury was assessed using propidium iodide (PI) fluorescence. ROS formation was quantified by using the 2′,7′-dichlorodihydrofluorescein diacetate (DCF-DA) method.Results: In mature slices, we found that the neurotoxicity, as well as oxidative stress, induced by OGD were enhanced by UCB. HSA significantly prevented UCB-increased neurotoxicity, but had a slight reduction on ROS production. Allopurinol, but not pioglitazone, significantly reduced UCB-increased neurotoxicity induced by OGD. In immature slices exposed to OGD, no increase of neuronal death was observed, whereas oxidative stress was detected after UCB exposure. HSA, pioglitazone and allopurinol have no protective effects on both OGD-induced neuronal death and on UCB-induced oxidative stress. For this reason, UCB, pioglitazone and allopurinol was also tested on ischemic preconditioning protocol. We found that UCB abolished the neuroprotection induced by preconditioning and increased oxidative stress. These effects were restored by allopurinol but not pioglitazone.Conclusions: UCB characterized a different path of neuronal damage and oxidative stress in mature and immature hippocampal slice model of HIE. Management of hyperbilirubinemia in a complex pathological condition, such as HIE and hyperbilirubinemia, should be very careful. Allopurinol could deserve attention as a novel pharmacological intervention for hyperbilirubinemia and HIE.

Life-Long Hyperbilirubinemia Exposure and Bilirubin Priming Prevent In Vitro Metabolic Damage

Background: Unconjugated bilirubin (UCB) is more than the final product of heme catabolism. Mildly elevated systemic bilirubin concentrations, such as in Gilbert syndrome (GS), protect against various oxidative stress-mediated and metabolic diseases, including cardiovascular disease, type 2 diabetes mellitus, metabolic syndrome, cancer, and age-related disease. The Gunn rat is an animal model of hereditary hyperbilirubinemia widely used in assessing the effect of high serum bilirubin concentration in various organs. The present work aims to understand if life-long hyperbilirubinemia and bilirubin-priming might contribute to protection against atherosclerosis and diabetic nephropathy (DN) at the cellular level.Methods: Primary aortic endothelial cells and podocytes obtained from hyperbilirubinemic homozygous jj and normobilirubinemic heterozygous Nj Gunn rats were exposed to Palmitic Acid (PA) and Angiotensin II (Ang II), respectively, and the effects on cell viability and the activation of damage-related metabolic pathways evaluated. Results were validated on immortalized H5V and HK2 cells exposed to damage after UCB pretreatment.Results: In both primary cell models, cells obtained from jj Gunn rats showed as significantly higher than Nj Gunn rats at any dose of the toxic agent. Reduction in CHOP expression and IL-6 release was observed in jj primary aortic endothelial cells exposed to PA compared to Nj cells. The same occurred on H5V pretreated with Unconjugated bilirubin. Upon Ang II treatment, primary podocytes from jj Gunn rats showed lower DNA fragmentation, cleaved caspase-3, and cleaved PARP induction than primary podocytes from Nj Gunn rats. In HK2 cells, the induction by Ang II of HIF-1α and LOXl2 was significantly reduced by UCB pretreatment.Conclusion: Our data suggest that in models of atherosclerosis and DN life–long hyperbilirubinemia exposure or bilirubin-priming significantly contribute to decrease the injury by enhancing thecellular defensive response,