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Pediatric Research Mar 2016Inherited disorders of hyperbilirubinemia may be caused by increased bilirubin production or decreased bilirubin clearance. Reduced hepatic bilirubin clearance can be... (Review)
Review
Inherited disorders of hyperbilirubinemia may be caused by increased bilirubin production or decreased bilirubin clearance. Reduced hepatic bilirubin clearance can be due to defective (i) unconjugated bilirubin uptake and intrahepatic storage, (ii) conjugation of glucuronic acid to bilirubin (e.g., Gilbert syndrome, Crigler-Najjar syndrome, Lucey-Driscoll syndrome, breast milk jaundice), (iii) bilirubin excretion into bile (Dubin-Johnson syndrome), or (iv) conjugated bilirubin re-uptake (Rotor syndrome). In this review, the molecular mechanisms and clinical manifestations of these conditions are described, as well as current approaches to diagnosis and therapy.
Topics: Animals; Bile; Bilirubin; Crigler-Najjar Syndrome; Gilbert Disease; Glucuronic Acid; Glucuronosyltransferase; Humans; Hyperbilirubinemia, Hereditary; Hyperbilirubinemia, Neonatal; Jaundice, Chronic Idiopathic; Liver
PubMed: 26595536
DOI: 10.1038/pr.2015.247 -
American Journal of Physiology.... Feb 2021Recent research on bilirubin, a historically well-known waste product of heme catabolism, suggests an entirely new function as a metabolic hormone that drives gene... (Review)
Review
Recent research on bilirubin, a historically well-known waste product of heme catabolism, suggests an entirely new function as a metabolic hormone that drives gene transcription by nuclear receptors. Studies are now revealing that low plasma bilirubin levels, defined as "hypobilirubinemia," are a possible new pathology analogous to the other end of the spectrum of extreme hyperbilirubinemia seen in patients with jaundice and liver dysfunction. Hypobilirubinemia is most commonly seen in patients with metabolic dysfunction, which may lead to cardiovascular complications and possibly stroke. We address the clinical significance of low bilirubin levels. A better understanding of bilirubin's hormonal function may explain why hypobilirubinemia might be deleterious. We present mechanisms by which bilirubin may be protective at mildly elevated levels and research directions that could generate treatment possibilities for patients with hypobilirubinemia, such as targeting of pathways that regulate its production or turnover or the newly designed bilirubin nanoparticles. Our review here calls for a shift in the perspective of an old molecule that could benefit millions of patients with hypobilirubinemia.
Topics: Animals; Bilirubin; Energy Metabolism; Gene Expression Regulation; Gilbert Disease; Heme; Hormones; Humans; Hyperbilirubinemia; Metabolic Networks and Pathways; PPAR alpha
PubMed: 33284088
DOI: 10.1152/ajpendo.00405.2020 -
Srpski Arhiv Za Celokupno Lekarstvo 2014Inherited disorders of bilirubin metabolism involve four autosomal recessive syndromes: Gilbert, CriglerNajjar, Dubin-Johnson and Rotor, among which the first two are... (Review)
Review
Inherited disorders of bilirubin metabolism involve four autosomal recessive syndromes: Gilbert, CriglerNajjar, Dubin-Johnson and Rotor, among which the first two are characterized by unconjugated and the second two by conjugated hyperbilirubinemia. Gilbert syndrome occurs in 2%-10% of general population, while others are rare. Except for Crigler-Najjar syndrome, hereditary hyperbilirubinemias belong to benign disorders and thus no treatment is required.
Topics: Bilirubin; Crigler-Najjar Syndrome; Gilbert Disease; Humans; Hyperbilirubinemia; Hyperbilirubinemia, Hereditary
PubMed: 24839786
DOI: 10.2298/sarh1404257r -
Frontiers in Pharmacology 2021Unconjugated bilirubin (UCB) is more than the final product of heme catabolism. Mildly elevated systemic bilirubin concentrations, such as in Gilbert syndrome (GS),...
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. 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. 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. 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.
PubMed: 33776779
DOI: 10.3389/fphar.2021.646953 -
Journal of the American Board of Family... 2012This issue includes several articles about various cardiovascular illnesses.(1-4) and another on a disease with increased risk for heart disease: hereditary...
This issue includes several articles about various cardiovascular illnesses.(1-4) and another on a disease with increased risk for heart disease: hereditary hemochromatosis.(5) Yet another explores some myth busting about mortality and diabetes.(6) Two articles provide data with the support of patient and/or family organizations (Parent Heart Watch(1) and the Iron Disorders Institute(5)). Another 2 articles address maternal-child health, one considers treatment of hyperbilirubinemia,(7) and one describes an innovative team structure for pre-, post-, and intrapartum care.(8) We also provide preliminary data on azithromycin for chronic obstructive pulmonary disease. Pop quiz: What is the common contaminant with cocaine that causes serious side effects? What are these side effects? And another: What nonliver disease should be considered for children with elevated transaminase levels? (See the brief reports for answers.) Two reviews provide up-to-the minute practical facts for vaccinations and treatment-resistant hypertension that can be immediately incorporated into clinical practice. We also have an update on physician perspectives after 2 years of electronic medical record use and another with insights about the satisfaction of family physicians who are working in health centers in the first few years out of their residency.
Topics: Cardiovascular Diseases; Clinical Medicine; Evidence-Based Medicine; Health Services Research; Humans; Primary Health Care
PubMed: 22773706
DOI: 10.3122/jabfm.2012.04.120113 -
Molecular Pharmacology May 2017Hyperbilirubinemia, caused by the accumulation of unconjugated bilirubin, is one of the most common clinical diagnoses in both premature and term newborns. Owing to the... (Review)
Review
Hyperbilirubinemia, caused by the accumulation of unconjugated bilirubin, is one of the most common clinical diagnoses in both premature and term newborns. Owing to the fact that bilirubin is metabolized solely through glucuronidation by UDP-glucuronosyltransferase (UGT) 1A1, it is now known that immaturity of UGT1A1, in combination with the overproduction of bilirubin during the developmental stage, acts as a bottleneck to bilirubin elimination and predisposes the infant to high total serum bilirubin levels. Although neonatal jaundice is mostly benign, excessively high levels of serum bilirubin in a small percentage of newborns can cause bilirubin-induced neurologic dysfunction, potentially leading to permanent brain damage, a condition known as Although a large portion of hyperbilirubinemia cases in newborns are associated with hemolytic diseases, we emphasize here the impaired ability of UGT1A1 to eliminate bilirubin that contributes to hyperbilirubinemia-induced neurotoxicity in the developmental stage. As a series of hereditary UGT1A1 mutations have been identified that are associated with UGT1A1 deficiency, new evidence has verified that delayed expression of UGT1A1 during the early stages of neonatal development is a tightly controlled event involving coordinated intrahepatic and extrahepatic regulation. This review recapitulates the progress that has been made in recent years in understanding the causes and physiopathology of severe hyperbilirubinemia, investigating molecular mechanisms underlying bilirubin-induced encephalopathy, and searching for potential therapies for treating pathologic hyperbilirubinemia. Several animal models have been developed to make it possible to examine bilirubin-induced neurotoxicity from multiple directions. Moreover, environmental factors that may alleviate or worsen the condition of hyperbilirubinemia are discussed.
Topics: Animals; Bilirubin; Diet; Glucuronosyltransferase; Humans; Hyperbilirubinemia, Neonatal; Infant, Newborn
PubMed: 28283555
DOI: 10.1124/mol.116.107524