A Morphology-based Analysis of Biliary Ductules After Kasai Procedure and a Review of the Literature

A Feasibility Study on 3-D Imaging of Intrahepatic Bile Ducts in Patients with Biliary Atresia Using Airy Beam Excited Two-Photon Microscopy

The purpose of this study was to utilize a two-photon microscope excitation Airy beam to achieve three-dimensional imaging of intrahepatic bile ducts in BDL mice and patients with biliary atresia (BA). Ten male Balb/c mice aged 6-8 weeks underwent extrahepatic bile duct ligation (BDL), and 10 underwent sham operation as control. After the operation, the mice resulted in symptoms such as jaundice, darkened urine, and weight loss. Taken liver tissues from BDL and control mice and trimmed to 5*5*3 mm3 after 10 days. Sixteen patients with BA were included in this study. Liver transplantation was performed in 12 cases of them; liver hilar and liver margin tissues were taken during the operation. Kasai portoenterostomy (KPE) was performed in 4 cases, and liver margin tissues were taken. Intraoperative liver tissue samples were trimmed to a size of 5*5*5 mm3. The specimens were subjected to tissue fixation, antigen retrieval, antibody incubation, and subsequent tissue hyalinization following the principles of immunofluorescence staining. Subsequently, light-sheet fluorescence microscopy (LSFM) was followed, and intrahepatic bile ducts of the specimen were imaged utilizing Airy beam which was excited with high imaging depth attenuation-compensated two-photon. Deconvolution was applied to image processing to construct a three-dimensional model of intrahepatic bile ducts. Three-dimensional imaging of liver tissue was conducted in both BDL mice and BA patients, and the distribution of intrahepatic bile ducts was visualized. BDL mice exhibited notable widening of intrahepatic bile ducts, accompanied by bile duct hyperplasia. There was no obvious hyperplasia of intrahepatic bile duct in the control group. Significant small bile duct hyperplasia was seen on imaging of the intrahepatic bile ducts in patients with BA. The intrahepatic bile duct was disorganized and hyperplasia especially in patients who performed liver transplantation. The technique of Airy beam three-dimensional reconstruction can effectively image the intrahepatic bile ducts in Balb/c mice and BA patients in three dimensions. This approach contributes to a better understanding of the distribution of intrahepatic bile ducts in BA patients. Moreover, it facilitates the exploration of models that more accurately simulate BA disease by elucidating the distribution of intrahepatic bile ducts in animal models. Understanding the distribution characteristics of intrahepatic bile duct will facilitate the formulation of hilar bile duct microstructure classification, which can guide the operation and evaluate the prognosis better.

Role of cholinergic innervation in biliary remnants of patients with biliary atresia

Objective

Biliary innervation is considered important in regulating the function of bile ducts, whereas the role of innervation in the hepatobiliary system of patients with biliary atresia (BA) remains unknown. This current study aims to investigate the role of innervation in biliary remnants and analyze the relationship between the innervation and prognosis of BA after surgery.

Methods

Eighty-seven patients with type III BA who underwent the Kasai procedure were consecutively enrolled from January 2017 to September 2020. Innervation and ductules in remnants were examined by pathologists. Liver function, onset of cholangitis, jaundice clearance, and survival with the native liver were recorded. Patients were followed up for 24 months. The relationship between innervation and prognosis was analyzed.

Results

In total, 67 patients had bile drainage postoperatively, and 21 biliary remnants contained neuronal plexuses where there was no neuron but nerve fiber bundles. Acetylcholinesterase staining was positive in all plexuses. In patients with bile drainage, those with plexuses had improved postoperative liver function, significantly better jaundice clearance 3 or 6 months postoperatively (50.0% vs. 19.1%, or 90.0% vs. 63.8%, respectively), fewer episodes of early cholangitis (10.0% vs. 34.0%), and better survival (80.0% vs. 61.7%) compared to those without. In addition, a larger area of plexuses was associated with a larger area of ductules (R2 = 0.786, p = 0.000), less frequent (p = 0.000) and later cholangitis onset (p = 0.012), and better jaundice clearance (p = 0.063).

Conclusions

Increased cholinergic innervation in biliary remnants may help reduce the onset of cholangitis and lead to better and earlier jaundice clearance. Thus, it improves the postoperative prognosis of patients with BA.

Insight into microvascular adaptive alterations in the Glisson system of biliary atresia after Kasai portoenterostomy using X-ray phase-contrast CT

OBJECTIVES

To investigate microvascular alterations in the Glisson system of biliary atresia (BA) patients after Kasai portoenterostomy (KP) using three-dimensional (3D) virtual histopathology based on X-ray phase-contrast CT (PCCT).

METHODS

Liver explants from BA patients were imaged using PCCT, and 32 subjects were included and divided into two groups: KP (n = 16) and non-KP (n = 16). Combined with histological analysis and 3D visualization technology, 3D virtual histopathological assessment of the biliary, arterial, and portal venous systems was performed. According to loop volume ratio, 3D spatial density, relative surface area, tortuosity, and other parameters, pathological changes of microvasculature in the Glisson system were investigated.

RESULTS

In the non-KP group, bile ducts mostly manifested as radial multifurcated hyperplasia and twisted into loops. In the KP group, the bile duct hyperplasia was less, and the loop volume ratio of bile ducts decreased by 13.89%. Simultaneously, the arterial and portal venous systems presented adaptive alterations in response to degrees of bile duct hyperplasia. Compared with the non-KP group, the 3D spatial density of arteries in the KP group decreased by 3.53%, and the relative surface area decreased from 0.088 ± 0.035 to 0.039 ± 0.015 (p < .01). Deformed portal branches gradually recovered after KP, with a 2.93% increase in 3D spatial density and a decrease in tortuosity from 1.17 ± 0.06 to 1.14 ± 0.04 (p < .01) compared to the non-KP group.

CONCLUSION

3D virtual histopathology via PCCT clearly reveals the microvascular structures in the Glisson system of BA patients and provides key insights into the morphological mechanism of microvascular adaptation induced by biliary tract dredging after KP in BA disease.

KEY POINTS

• 3D virtual histopathology via X-ray phase-contrast computed tomography clearly presented the morphological structures and pathological changes of microvasculature in the Glisson system of biliary atresia patients. • The morphological alterations of microvasculature in the Glisson system followed the competitive occupancy mechanism in the process of biliary atresia.

Developmental histology of the portal plate in biliary atresia: observations and implications

PURPOSE

The key characteristic of biliary atresia (BA) is obliteration of the extrahepatic bile ducts at the level of the porta hepatis. We aimed to relate the immunohistochemical features of remnant biliary ductules at the porta hepatis with clinical features and outcomes.

METHODS

Samples were immunostained with anti-cytokeratin 20 (CK20), vimentin and alpha-smooth muscle actin (aSMA). Primary outcome was set as clearance of jaundice (bilirubin ≤ 20 μmol/L) following Kasai portoenterostomy (KPE).

RESULTS

Eighty-two cases were classified into syndromic BA (n = 10), cystic BA (n = 7), CMV IgM+ BA (n = 9) and isolated BA (n = 56). CK20 expression was confirmed in 40/82 (49%), and vimentin expression in 19/82 (23%). aSMA was negative in all cases studied. CK20 expression was less common in isolated BA (n = 20/56, 36%) compared to CMV IgM+ BA (n = 8/9, 89%), cystic BA (n = 7/7, 100%) (isolated BA vs non-isolated BA, P = 0.0008). There was no difference in vimentin expression among the sub-groups (isolated BA vs. non-isolated BA; P = 0.39). CoJ was achieved in 52/82 (63%) overall with significant difference depending simply on sub-group [e.g. syndromic BA 9/10 (90%)]. CK20 expression was associated with a diminished rate of CoJ in the entire cohort [CK20+ 32/56 (57%) vs. CK20- 20/26 (77%); P = 0.04]. By contrast no correlation was observed between vimentin expression and CoJ (P = 0.13).

CONCLUSION

CK20+ expression was associated with reduced clearance of jaundice in BA and a trend towards reduced native liver survival.