Potential of therapeutic bile acids in the treatment of neonatal Hyperbilirubinemia

Bile Acids Promote Hepatic Biotransformation and Excretion of Aflatoxin B1 in Broiler Chickens

Aflatoxin B1 (AFB1) is a hazardous mycotoxin that often contaminates animal feed and may potentially induce severe liver damage if ingested. The liver is the primary organ responsible for AFB1 detoxification through enzyme-catalyzed xenobiotic metabolism and bile acid (BA)-associated excretion. In this study, we sought to investigate whether exogenous BA improves hepatic AFB1 detoxification to alleviate AFB1-induced liver injury in broiler chickens. Five-day-old broiler chicks were randomly assigned to three groups. CON and AFB1 received a basal diet; AFB1 + BA received a basal diet with 250 mg/kg BA for 20 days. After a 3-day pre-feed, AFB1 and AFB1 + BA were daily gavaged with 250 μg/kg BW AFB1, while CON received gavage solvent for AFB1 treatment. Dietary BA supplementation protected chickens from AFB1-induced hepatic inflammation and oxidative stress. The hepatic biotransformation of AFB1 to its metabolite AFBO was improved, with accelerated excretion to the gallbladder and cecum. Accordantly, AFB1-induced down-regulation of detoxification genes, including cytochrome P450 enzymes, glutathione S-transferases, and the bile salt export pump, was rescued by BA supplementation. Moreover, liver X receptor α, suppressed by AFB1, was enhanced in BA-treated broiler chickens. These results indicate that dietary BA supplementation improves hepatic AFB1 detoxification and excretion through LXRα-involved regulation of xenobiotic enzymes.

An evaluation of ursodeoxycholic acid treatment in prolonged unconjugated hyperbilirubinemia due to breast milk

Background/Aim

Prolonged jaundice is one of the most common problems during neonatal period. The aim of this study was to evaluate the efficiency of ursodeoxycholic acid (UDCA) treatment in newborn infants with prolonged unconjugated hyperbilirubinemia.

Materials and Methods

The present study included 27 patients who were fed by breast milk and followed up in the outpatient clinic due to prolonged jaundice without any underlying etiological factor; 10 mg/kg/day UDCA was administrated in two doses for 7 days. Furthermore, 20 newborns diagnosed with prolonged jaundice with same characteristics were enrolled as the control group. The control group was also given a placebo; demographic characteristics, liver functions tests before and after the treatment, bilirubin decrease rates, and hemogram parameters of groups were compared.

Results

Total bilirubin levels in the study and control groups before the treatment were 16.02 ± 1.41 mg/dL and 15.93 ± 1.66 mg/dL, respectively (P = 0.84). Total bilirubin levels in the study and control groups at day 7 after UDCA treatment were detected 8.18 ± 2.31 mg/dL and 13.92 ± 2.66 mg/dL, respectively (P < 0.001), and at day 14 after the treatment were 5.45 ± 2.59 mg/dL and 11.91 ± 2.83 mg/dL, respectively (P < 0.001). Furthermore, serum aspartate aminotransferase (AST) was detected <21 U/L in the ROC analysis after UDCA treatment (P = 0.04).

Conclusion

The study outcomes indicated that an efficient reduction in total bilirubin levels may be achieved, and outpatient clinic follow-up period may be reduced in patients whom UDCA was administrated. Moreover, it may be speculated that AST can be used to evaluate the efficacy after treatment. However, studies with larger sample sizes are needed for the routine use of UDCA in the treatment of prolonged jaundice.

Effectiveness and safety of prophylactic phototherapy to prevent jaundice in premature newborns: Systematic review and meta-analysis

To determine the effectiveness and safety of prophylactic phototherapy compared with conventional phototherapy for the prevention of neonatal jaundice. We included clinical trials comparing prophylactic phototherapy to conventional phototherapy to prevent jaundice in premature newborns. We searched Embase, MEDLINE, LILACS, Central, and others. The statistical analysis was performed in RevMan (Review Manager 5.3). Outcomes were analyzed according to the type of variable: risk difference (RD) and mean difference (MD). A random effects model was used due to heterogeneity. We reported results in forest plots. Risk of bias was evaluated, and a sensitivity analysis was made. 1127 articles were found, and six studies (2332 patients) were included in the meta-analysis. Five studies evaluated the need for exchange transfusion as the primary outcome RD -0.01, 95% CI [-0.05 to 0.03]. One study evaluated bilirubin encephalopathy RD -0.04, 95% CI [-0.09 to 0.00]. Five studies evaluated the duration of phototherapy, MD 38.47, 95% CI [1.28 to 55.67]. Four studies evaluated levels of bilirubin (MD -1.23, 95% CI [-2.25 to -0.21]. Two studies evaluated mortality, RD 0.01, 95% CI [-0.03 to 0.04]. As a conclusion, compared to conventional phototherapy, prophylactic phototherapy decreases the last measured level of bilirubin, as well as the probability of neurodevelopmental disturbances. However, it increases phototherapy duration.

Impact of Protein Binding Capacity and Daily Dosage of a Drug on Total Serum Bilirubin Levels in Susceptible Infants

Hyperbilirubinemia is a common pathological condition in neonates. Free bilirubin can penetrate the blood-brain barrier (BBB), which can lead to bilirubin neurotoxicity. In the context of predicting the risk of bilirubin neurotoxicity, although the specificity and sensitivity of free bilirubin levels are higher than those of total serum bilirubin (TSB), free bilirubin is not widely monitored in clinical practice. The threshold TSB levels at which phototherapy must be administered have been established previously. However, TSB levels are not well correlated with neurodevelopmental outcomes. Currently, TSB levels are commonly used to guide phototherapy for neonatal hyperbilirubinemia. Some clinical drugs can displace bilirubin from its albumin-binding sites, and consequently upregulate plasma bilirubin. Daily dosages play a vital role in regulating bilirubin levels. A drug with both a high protein binding capacity and high daily dosage significantly increases bilirubin levels in infants. Premature or very low birth weight (VLBW) infants are vulnerable to the upregulation of bilirubin levels as they exhibit the lowest reserve albumin levels and consequently the highest bilirubin toxicity index. Because bilirubin is involved in maintaining the balance between pro-oxidant and antioxidant agents, the downregulation of bilirubin levels is not always desirable. This review provides insights into the impact of protein binding capacity and daily dosage of drugs on the bilirubin levels in susceptible infants.

Novel insights into bile acid detoxification via CYP, UGT and SULT enzymes

Bile acid (BA) homeostasis is a complex and precisely regulated process to prevent impaired BA flow and the development of cholestasis. Several reactions, namely hydroxylation, glucuronidation and sulfation are involved in BA detoxification. In the present study, we employed a comprehensive approach to identify the key enzymes involved in BA metabolism using human recombinant enzymes, human liver microsomes (HLM) and human liver cytosol (HLC). We showed that CYP3A4 was a crucial step for the metabolism of several BAs and their taurine and glycine conjugated forms and quantitatively described their metabolites. Glucuronidation and sulfation were also identified as important drivers of the BA detoxification process in humans. Moreover, lithocholic acid (LCA), the most hydrophobic BA with the highest toxicity potential, was a substrate for all investigated processes, demonstrating the importance of hepatic metabolism for its clearance. Collectively, this study identified CYP3A4, UGT1A3, UGT2B7 and SULT2A1 as the major contributing (metabolic) processes in the BA detoxification network. Inhibition of these enzymes by drug candidates is therefore considered as a critical mechanism in the manifestation of drug-induced cholestasis in humans and should be addressed during the pre-clinical development.

Effects of Two Different Doses of Ursodeoxycholic Acid on Indirect Hyperbilirubinemia in Neonates with Glucose-6-phosphate Dehydrogenase Deficiency Treated with Phototherapy: A Randomized Controlled Trial

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the causes of severe hyperbilirubinemia, prolonged jaundice, and bilirubin-induced encephalopathy in neonates. In a randomized controlled trial, we evaluated the effect of oral ursodeoxycholic acid (UDCA) on indirect hyperbilirubinemia in G6PD-deficient neonates requiring phototherapy. Intervention group I (N = 45; received phototherapy and 10 mg/kg/day UDCA), Intervention group II (N = 40; received phototherapy and 20 mg/kg/day UDCA), and a control group (N = 49; received phototherapy and placebo). Levels of total serum bilirubin (TSB) in all 3 groups decreased significantly over time (P = .001) but the level of TSB at different hours after admission and the duration of phototherapy did not differ significantly between the 3 groups. After discharge, the 2 intervention groups had a significantly lower rate of readmission than the control group (P = .001). No significant difference was observed between the 10 and 20 mg/kg/day groups. Further evaluation is recommended, especially in terms of the pharmacokinetics of UDCA in neonates. Trial registration number: IRCT20091201002801N4, prospectively registered on 2019-06-1.

Pharmaceutical strategies for preventing toxicity and promoting antioxidant and anti-inflammatory actions of bilirubin

Bilirubin (BR) is the final product of haem catabolism. Disruptions along BR metabolic/transport pathways resulting from inherited disorders can increase plasma BR concentration (hyperbilirubinaemia). Unconjugated hyperbilirubinemia may induce BR accumulation in brain, potentially causing irreversible neurological damage, a condition known as BR encephalopathy or kernicterus, to which newborns are especially vulnerable. Numerous pharmaceutical strategies, mostly based on hemoperfusion, have been proposed over the last decades to identify new valid, low-risk alternatives for BR removal from plasma. On the other hand, accumulating evidence indicates that BR produces health benefits due to its potent antioxidant, anti-inflammatory and immunomodulatory action with a significant potential for the treatment of a multitude of diseases. The present manuscript reviews both such aspects of BR pharmacology, gathering literature data on applied pharmaceutical strategies adopted to: (i) reduce the plasma BR concentration for preventing neurotoxicity; (ii) produce a therapeutic effect based on BR efficacy in the treatment of many disorders.

Ursodeoxycholic acid use in lactating female patients is associated with clinically negligible concentrations of this bile acid in breast milk

In the literature on the safety of ursodeoxycholic acid (UDCA) during breastfeeding, insufficient data has been reported to date. Thus, the aim of our study was to analyze bile acid (BA) concentrations in breast milk in a cohort of patients, treated with UDCA, and with various cholestatic liver diseases. The study was carried out on a cohort of 20 patients with various cholestatic diseases. All the patients were treated with UDCA (500-1500 mg daily). Concentrations of BA, sampled on day 3 after delivery were analyzed using the GS-MS technique, and then compared to untreated women. Total BA concentrations in the breast milk of the UDCA-treated patients were equal to those of the untreated women controls (3.2 ± 1 vs. 3.2 ± 0.2 µmol/L, respectively). The UDCA concentrations in breast milk remained negligible in UDCA-treated patients (0.69 µmol/L), and in any event did not contribute to the newborn BA pool. No apparent side-effects of the maternal UDCA treatment were observed in any newborn infant, and no deterioration in postnatal development was observed during the routine 1-year follow-ups. Therapeutic administration of UDCA during lactation is safe for breastfed babies since UDCA only gets into breast milk in negligible amounts. UDCA treatment should be allowed and included into the guidelines for the therapy of cholestatic diseases in breastfeeding mothers.

Activation of Alternative Bilirubin Clearance Pathways Partially Reduces Hyperbilirubinemia in a Mouse Model Lacking Functional Ugt1a1 Activity

Bilirubin is a heme catabolite and Ugt1a1 is the only enzyme involved in the biological elimination of bilirubin. Partially functional or non-functional Ugt1a1 may result in neuronal damage and death due to the accumulation of unconjugated bilirubin in the brain. The understanding of the role of alternative bilirubin detoxification mechanisms that can reduce bilirubin toxicity risk is crucial for developing novel therapeutic strategies. To provide a proof-of-principle showing whether activation of alternative detoxification pathways could lead to life-compatible bilirubin levels in the absence of Ugt1a1 activity, we used Ugt1^−/− hyperbilirubinemic mice devoid of bilirubin glucuronidation activity. We treated adult Ugt1^−/− mice with TCPOBOP, a strong agonist of the constitutive androstane receptor (CAR). TCPOBOP treatment decreased plasma and liver tissue bilirubin levels by about 38%, and resulted in the transcriptional activation of a vast array of genes involved in bilirubin transport and metabolism. However, brain bilirubin level was unaltered. We observed ~40% degradation of bilirubin in the liver microsomes from TCPOBOP treated Ugt1^−/− mice. Our findings suggest that, in the absence of Ugt1a1, the activation of alternative bilirubin clearance pathways can partially improve hyperbilirubinemic conditions. This therapeutic approach may only be considered in a combinatorial manner along with other treatments.

Targeting gut microbial bile salt hydrolase (BSH) by diet supplements: new insights into dietary modulation of human health

Dietary supplements could modulate the abundance of BSH-producing bacteria to regulate the BSH enzyme activity, thereby change the BAs composition to regulate FXR signaling, which then regulate human health.

Ursodeoxycholic acid as adjuvant treatment to phototherapy for neonatal hyperbilirubinemia: a systematic review and meta-analysis

BACKGROUND

Neonatal hyperbilirubinemia is observed in most newborns, and 5-15% of neonates require phototherapy. Phototherapy is effective but often prolongs hospitalization and has both short-term and potential long-term harms. The aim of this systematic review and meta-analysis was to evaluate the role of ursodeoxycholic acid (UDCA) combined with phototherapy in neonatal hyperbilirubinemia.

METHODS

A literature search was conducted on September 1, 2021; 590 studies were screened, and 17 full texts were assessed by two authors. We included randomized controlled trials with or without placebo intervention. Primary outcomes were changes in total bilirubin levels at 24 hours and phototherapy duration. We calculated mean differences with 95% confidence intervals (CI).

RESULTS

Six studies with 880 neonates were included. Of these studies, only two used a placebo-controlled double-blinded design. The overall risk of bias was high in one and moderate in four of the included studies. The mean decrease in the total bilirubin level during the first 24 hours was 2.06 mg/dL (95% CI 0.82-3.30; six studies) greater in the UDCA treatment group. The phototherapy duration was 19.7 hours (95% CI 10.4-29.1; five studies) shorter in the UDCA treatment group.

CONCLUSIONS

We found low-quality evidence that UDCA as an adjuvant to phototherapy seems to decrease total bilirubin faster and shorten phototherapy duration compared to standard treatment. Further studies are needed to confirm the efficacy, acute and long-term outcomes, and safety before implementing UDCA as an adjuvant to phototherapy in neonatal hyperbilirubinemia.