Can Free Carnitine or Bilirubin in Blood Be Used in Neonatal Screening for Biliary Atresia?

Population-based screening strategies for biliary atresia in the newborn: A systematic review and meta-analysis

BACKGROUND

Newborn screening for biliary atresia (BA) may facilitate earlier diagnosis and intervention for improved clinical outcomes.

METHODS

We systematically reviewed the accuracy of population-based screening strategies for BA in the newborn using PRISMA-DTA guidelines. We included cohort or cross-sectional studies. The screening (index) tests included stool color card (SCC) and direct/conjugated bilirubin (DB/CB) and the reference standard was intraoperative cholangiogram. Meta-analysis was performed using random-effects logistic regression models.

RESULTS

We included 15 studies (1,816,722 participants) that assessed 5 different population-based screening strategies. QUADAS-2 assessment revealed high risk of bias for patient selection in one study and uncertain risks for reference standard in multiple studies. High certainty evidence suggests that DB/CB assessed after birth had a summary sensitivity of 100% (95% CI 100,100) and specificity of 98.8% (98.8,98.9) (5 studies, 662141 participants). Moderate certainty evidence suggests that SCC screening at a month of age had summary sensitivity of 79.6% (95% CI 70.6, 86.4) and specificity of 99.9% (95% CI 99.9, 99.9) (7 studies, 996262 participants).

CONCLUSIONS

DB/CB in the first few days of life has the best diagnostic accuracy for population screening for biliary atresia in the newborn. Future research should focus on cost-effectiveness and combinations of screening strategies.

Population-based screening methods in biliary atresia: a systematic review and meta-analysis

OBJECTIVE

The aim of this study was to investigate tested methods of population-based biliary atresia (BA) screening.

DESIGN

We searched 11 databases between 1 January 1975 and 12 September 2022. Data extraction was independently done by two investigators.

MAIN OUTCOME MEASURES

Our primary outcomes were: sensitivity and specificity of screening method in BA detection, age at Kasai, BA associated morbidity and mortality, cost-effectiveness of screening.

RESULTS

Six methods of BA screening were evaluated: stool colour charts (SCCs), conjugated bilirubin measurements, stool colour saturations (SCSs), measurements of urinary sulfated bile acids (USBAs), assessments of blood spot bile acids and blood carnitine measurements.In a meta-analysis, USBA was the most sensitive and specific, with a pooled sensitivity and specificity of 100.0% (95% CI 2.5% to 100.0%) and 99.5% (95% CI 98.9% to 99.8%) (based on one study). This was followed by conjugated bilirubin measurements: 100.0% (95% CI 0.0% to 100.0%) and 99.3% (95% CI 91.9% to 99.9%), SCS: 100.0% (95% CI 0.00% to 100.0%) and 92.4% (95% CI 83.4% to 96.7%), and SCC: 87.9% (95% CI 80.4% to 92.8%) and 99.9% (95% CI 99.9% to 99.9%).SCC reduced the age of Kasai to ~60 days, compared with 36 days for conjugated bilirubin. Both SCC and conjugated bilirubin improved overall and transplant-free survival. The use of SCC was considerably more cost-effective than conjugated bilirubin measurements.

CONCLUSION

Conjugated bilirubin measurements and SCC are the most researched and demonstrate improved sensitivity and specificity in detecting BA. However, their use is expensive. Further research into conjugated bilirubin measurements, as well as alternative methods of population-based BA screening, is required.

PROSPERO REGISTRATION NUMBER

CRD42021235133.

Reduced peroxisome proliferator-activated receptor-α and bile acid nuclear receptor NR1H4/FXR may affect the hepatic immune microenvironment of biliary atresia

Background

Biliary atresia (BA) is a childhood liver disease characterized by fibrous obstruction and obstruction of the extrahepatic biliary system and is one of the most common and serious biliary disorders in infants. Significant inflammation and fibrosis of the liver and biliary tract are the most prominent features, regardless of the initial damage to the BA. Abnormalities in innate or adaptive immunity have been found in human patients and mouse models of BA. We previously reported that children with BA had abnormal lipid metabolism, including free serum carnitine.

Objective

To study gene and protein expression levels of the hepatic peroxisome proliferator-activated receptor-α (PPARα) signaling pathway and farnesoid X receptor (FXR) in BA and BA fibrosis, and assess their clinical values.

Methods

Low expression of PPARα and NR1H4 (FXR) in BA were validated in the Gene Expression Omnibus database. Functional differences were determined by gene set enrichment analysis based on of PPARα and NR1H4 expression. BA patients from GSE46960 were divided into two clusters by using consensus clustering according to PPARα, NR1H4, and SMAD3 expression levels, and immunoinfiltration analysis was performed. Finally, 58 cases treated in our hospital were used for experimental verification. (IHC: 10 Biliary atresia, 10 choledochal cysts; PCR: 10 Biliary atresia, 14 choledochal cysts; WB: 10 Biliary atresia, 4 choledochal cysts).

Results

Bioinformatics analysis showed that the expression of PPARα, CYP7A1 and NR1H4 (FXR) in the biliary atresia group was significantly lower than in the control group. More BA-specific pathways, including TGFβ signaling pathway, P53 signaling pathway, PI3K-AKT-mTOR signaling pathway, etc., are enriched in BA patients with low PPARα and NR1H4 expression. In addition, low NR1H4 expression is abundant in inflammatory responses, IL6/STAT3 signaling pathways, early estrogen responses, IL2 STAT5 signaling pathways, and TGFβ signaling pathways. The TGFβ signaling pathway was significant in both groups. According to the expression of PPARα, NR1H4 and SMAD3, a key node in TGFβ pathway, BA patients were divided into two clusters using consensus clustering. In cluster 2, SMAD3 expression was high, and PPARα and NR1H4 expression were low. In contrast to cluster 1, immune cell infiltration was higher in cluster 2, which was confirmed by immunohistochemistry. The mRNA and protein levels of PPARα and NR1H4 in BA patients were lower than in the control group by immunohistochemistry, Western blot analysis and real-time PCR.

Conclusions

The downregulation of PPARα and NR1H4 (FXR) signaling pathway may be closely related to biliary atresia.

Diagnostic Yield of Newborn Screening for Biliary Atresia Using Direct or Conjugated Bilirubin Measurements

IMPORTANCE

Treating biliary atresia in newborns earlier can delay or prevent the need for liver transplant; however, treatment typically occurs later because biliary atresia is difficult to detect during its early stages.

OBJECTIVE

To determine the diagnostic yield of newborn screening for biliary atresia with direct or conjugated bilirubin measurements and to evaluate the association of screening implementation with clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional screening study of 124 385 infants born at 14 Texas hospitals between January 2015 and June 2018; and a pre-post study of 43 infants who underwent the Kasai portoenterostomy as treatment for biliary atresia at the region's largest pediatric hepatology center before (January 2008-June 2011) or after (January 2015-June 2018) screening implementation. Final follow-up occurred on July 15, 2019.

EXPOSURES

Two-stage screening with direct or conjugated bilirubin measurements. In stage 1, all newborns were tested within the first 60 hours of life, with a positive screening result defined as bilirubin levels exceeding derived 95th percentile reference intervals. In stage 2, infants who had a positive screening result in stage 1 were retested at or before the 2-week well-child visit, with a positive screening result defined as bilirubin levels greater than the stage 1 result or greater than 1 mg/dL.

MAIN OUTCOMES AND MEASURES

The primary outcomes of the screening study were sensitivity, specificity, positive predictive value, and negative predictive value based on infants testing positive in both stages. The reference standard was biliary atresia diagnosed at the region's pediatric hepatology centers. The primary outcome of the pre-post study was the age infants underwent the Kasai portoenterostomy for treatment of biliary atresia.

RESULTS

Of 124 385 newborns in the screening study, 49.2% were female, 87.6% were of term gestational age, 70.0% were white, and 48.1% were Hispanic. Screening identified the 7 known infants with biliary atresia with a sensitivity of 100% (95% CI, 56.1%-100.0%), a specificity of 99.9% (95% CI, 99.9%-99.9%), a positive predictive value of 5.9% (95% CI, 2.6%-12.2%), and a negative predictive value of 100.0% (95% CI, 100.0%-100.0%). In the pre-post study, 24 infants were treated before screening implementation and 19 infants were treated after screening implementation (including 6 of 7 from the screening study, 7 from screening at nonstudy hospitals, and 6 from referrals because of clinical symptoms). The age infants underwent the Kasai portoenterostomy was significantly younger after screening was implemented (mean age, 56 days [SD, 19 days] before screening implementation vs 36 days [SD, 22 days] after screening implementation; between-group difference, 19 days [95% CI, 7-32 days]; P = .004).

CONCLUSIONS AND RELEVANCE

Newborn screening with direct or conjugated bilirubin measurements detected all known infants with biliary atresia in the study population, although the 95% CI around the sensitivity estimate was wide and the study design did not ensure complete ascertainment of false-negative results. Research is needed in larger populations to obtain more precise estimates of diagnostic yield and to better understand the clinical outcomes and cost-effectiveness of this screening approach.