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Updated: May 31, 2025
Generation and Quantitative Characterization of Functional and Polarized Biliary Epithelial Cysts
Published on: May 16, 2020
Structural Disruption of Cilia and Increased Cytoplasmic Tubulin in Biliary Atresia-An Exploratory Study Focusing on
Patrícia Quelhas1, Rui Oliveira2,3,4, Carlos Kieling5
1Faculty of Health Sciences, Health Science Investigation Center of University of Beira Interior (CICS-UBI), 6200-506 Covilhã, Portugal.
Insights
Biliary atresia (BA) in infants is linked to shorter primary cilia (PC) and increased cytoplasmic tubulin (TUBA4A), negatively impacting liver survival. These changes, along with hypoxia markers, predict poor early prognosis in BA patients.
Area of Science:
- Hepatology and Gastroenterology
- Pediatric Surgery
- Cell Biology
Background:
- Biliary atresia (BA) is a severe infant liver disease leading to failure and transplantation.
- The exact causes of BA are unknown, but primary cilia (PC) dysfunction is a suspected factor.
- Investigating PC and tubulin alterations in BA may reveal insights into disease progression and prognosis.
Purpose of the Study:
- To examine the relationship between primary cilia (PC) and cytoplasmic tubulin (TUBA4A) changes in infants with isolated biliary atresia (BA).
- To correlate these cellular alterations with hypoxia markers (HIF-1α) and predict early native liver survival.
- To understand the impact of these factors on prognosis following portoenterostomy.
Main Methods:
- Immunofluorescence staining and digital image analysis were used on liver samples from 14 BA patients and 6 controls.
- Primary cilia (PC) length, bending, and ratio, along with cytoplasmic TUBA4A levels, were quantified.
- Correlations were assessed with HIF-1α positivity, clinical data, and early native liver survival using statistical analysis.
Main Results:
- HIF-1α positivity was found in 42.8% of BA patients.
- BA patients exhibited decreased PC length and increased cytoplasmic TUBA4A expression compared to controls.
- Reduced PC length, PC bending, and elevated TUBA4A were significant predictors of poor early prognosis in BA.
Conclusions:
- Decreased PC length, PC bending, and increased cytoplasmic TUBA4A intensity are characteristic of isolated BA and worsen early prognosis.
- These findings suggest a disruption in tubulin transport between the cytoplasm and primary cilia (PC) in BA.
- Hypoxia pathway activation negatively affects early native liver survival in BA, independent of PC or tubulin alterations.
Abstract:
Introduction: Biliary atresia (BA) is a progressive hepatobiliary disease in infants, leading to liver failure and the need for transplantation. While its etiopathogenesis remains unclear, recent studies suggest primary cilia (PC) disruption plays a role. This study investigates correlations between PC and cytoplasmic tubulin (TUBA4A) alterations with hypoxia in patients with the isolated form of BA, focusing on native liver survival. Methods: Using qualitative and quantitative digital image analysis of immunofluorescence-stained liver samples, we assessed PC and TUBA4A features correlating these findings with HIF-1α nuclear positivity, clinical-laboratory data, and early native liver survival. Liver samples from fourteen BA patients and six controls with another liver disease were analyzed by digital image analysis, with data evaluated using Spearman's correlation and independent t-tests. Results: HIF-1α positivity in cholangiocytes was observed in 42.8% of BA patients. While the PC ratio per biliary structure (cilia ratio status, CRs) was similar between BA patients and controls, PC length was decreased in BA patients. Cytoplasmic TUBA4A levels were elevated in BA patients. CRs positively correlated with lower cytoplasmic TUBA4A expression and was higher in patients without HIF-1α nuclear positivity. Reduced cilia length correlated with higher bilirubin levels at portoenterostomy. Predictors of early poor prognosis (death or need for transplantation until 1 year of life) included HIF-1α positivity, elevated direct bilirubin levels, decreased cilia length, PC bending, and increased TUBA4A expression. Conclusions: Reduced PC length, PC bending, and increased intensity of cytoplasmic TUBA4A expression occur in the isolated BA clinical type and negatively impact the early prognosis after post-portoenterostomy. These findings suggest the existence of a disruption in the tubulin transport between cytoplasm and PC. The detrimental effect of HIF-1alpha pathway activation over early native liver survival was confirmed, although independently from PC or cytoplasmic tubulin features.
