Bilirubin: The yellow hormone?

Bilirubin is a tetrapyrrolic compound originating from heme catabolism. Although originally considered only a potentially dangerous waste product, it has become increasingly evident that this molecule represents an important modulator of various biological functions in the human body. Bilirubin appears to have versatile functions, from cell signaling (behaving almost like a "real" hormonal substance), modulation of metabolism, to immune regulation, affecting biological activities with apparent clinical and even therapeutic consequences. These activities may be the reason for the lower incidence of diseases of civilisation (cardiovascular diseases, arterial hypertension, diabetes, obesity, metabolic syndrome, certain cancers, autoimmune, and neurodegenerative diseases) observed in individuals with a chronic mild unconjugated hyperbilirubinemia, a typical sign of Gilbert's syndrome. While higher serum concentrations of unconjugated bilirubin may serve as an important protective factor against these diseases, low levels of bilirubin are associated with the opposite effect.

Cigarette smoking and serum bilirubin subtypes in healthy Korean men: the Korea Medical Institute study.

OBJECTIVES: Cigarette smoking is a modifiable risk factor for cardiovascular disease. Bilirubin is a potent antioxidant and its concentration decreases in smokers. However, studies about the association between cigarette smoking and bilirubin are scarce and most are limited to total bilirubin. Additionally, bilirubin is highly related to hemoglobin. Therefore, this study evaluates the association between bilirubin subtypes and cigarette smoking in healthy Korean men independently of hemoglobin. METHODS: This study included 48 040 Korean men aged 30 to 87 years who visited the Korea Medical Institute for routine health examinations from January to December, 2007. The association of smoking with total, direct, and indirect bilirubin was assessed by logistic regression analysis taking into consideration differences in subjects and smoking characteristics. RESULTS: Current smokers had lower bilirubin concentrations than never-smokers and ex-smokers. Smoking amount and duration were inversely significantly associated with total, direct, and indirect bilirubin. In a multivariable adjusted model, compared to never-smokers, the odds ratios (ORs) and 95% confidence intervals (CIs) of current smokers with the highest number of pack-years were 1.7 (1.6 to 1.9) for total, 1.5 (1.4 to 1.6) for direct, and 1.7 (1.6 to 1.9) for indirect bilirubin. After further adjustment for hemoglobin, this association became stronger (OR [95% CI], 2.1 [1.9 to 2.2] for total; 1.9 [1.8 to 2.0] for direct; 2.0 [1.9 to 2.2] for indirect bilirubin). CONCLUSIONS: In this study, bilirubin subtypes are inversely associated with smoking status, smoking amount, and smoking duration in healthy Korean men independently of hemoglobin. Further studies are needed to investigate this association in healthy Korean women.

Ictericia y colestasis

La ictericia constituye la traducción clínica de la acumulación de pigmento biliar en el organismo que confiere a la piel y también a las mucosas una coloración amarilla. Su aparición es siempre consecutiva a una alteración del metabolismo de la bilirrubina y se detecta cuando su concentración plasmática es superior a 2 mg/dl. La orientación diagnóstica del paciente con hiperbilirrubinemia precisa, tal y como se describe en el texto, del conocimiento de la fracción de la bilirrubina que está más elevada en el suero, ya sea a expensas de la fracción conjugada o no conjugada. Las enfermedades que cursan con una hiperbilirrubinemia no congujada son pocofrecuentes, si bien el síndrome de Gilbert es la enfermedad que acontece en un porcentaje mayor de pacientes.Por otro lado, la colestasis es un síndrome clínico y bioquímico caracterizado por prurito, ictericia y elevación sérica de la fosfatasa alcalina, secundario a un trastorno excretor de la bilis y los aniones orgánicos. Las colestasis pueden ser intrahepáticas y engloban diferentes procesos que alteran la excreción biliar parenquimatosa o extrahepáticas secundarias a la obstrucción mecánica de las grandes vías biliares. De entre todas las causas posibles, las enfermedades colestásicas más importantes son la cirrosis biliar primaria y la colangitis esclerosante primaria (AU)

Correlaçäo dos aspectos ultra-sonográficos com a classificaçäo clínica de child na cirrose hepática / Analyzing the echografpic alterations of the hepatic cirrhosis and matching them with the clinical classification of Child

Analisamos 165 pacientes com diagnóstico de cirrose hepática, avaliados clinicamente segundo a classificaçäo de Child, submetidos à ultra-sonografia abdominal e a dosagens séricas de alfa-fetoproteína (AFP), no período entre janeiro de 1994 e dezembro de 1995. O interesse deste estudo consiste em analisar as alteraçöes ecográficas da cirrose hepática e correlacioná-las com a classificaçäo clínica de Child. foi feita, também, análise da taxa de incidência do carcinoma hepatocelular e dos nódulos de regeneraçäo, correlacionando-os com os níveis séricos de AFP. Os resultados obtidos a partir deste estudo foram: do total dos pacientes examinados, 96 (58,2 por cento) pertenciam ao estádio Chid A, 61 (37.0 p/cento) ao Child B e 8 (4,8 por cento) ao Child C. Os níveis

[Is fractionation of serum bilirubin useless?]. / Fraktionierung des Serumbilirubins wertlos?

The validity of fractionation of serum bilirubin into direct and indirect fractions for differentiation of haemolytic and hepatobiliary hyperbilirubinaemia was assessed in 20 patients with haemolysis and 72 patients with hepatobiliary diseases. The groups varied significantly regarding the ratio of direct and total bilirubin (0.45 +/- 0.24 vs. 0.58 +/- 0.18, P less than 0.005). Due to the frequency distribution between both groups in each patient there was an a-priori probability of haemolysis of 22% and of hepatobiliary disease of 78%. Fractionation increased the probability of correct diagnosis from 22% to 55% and from 78% to 91%. Exclusion of patients with a total bilirubin of more than 3 mg/dl (51 mumol/l) increased the probability from 26% to 80% and from 74% to 86%. Thus fractionation of serum bilirubin is a considerable gain for the diagnosis of haemolysis, particularly in relatively low total bilirubin. The more frequent hepatobiliary diseases can be better diagnosed using other laboratory methods. Thus fractionation is useful only when a hepatobiliary disease has been established as unlikely beforehand.