Does Biliodigestive Anastomosis Have Any Effect on the Reversal of Hepatopulmonary Syndrome in a Biliary Cirrhosis Experimental Model?

BACKGROUND: Biliary cirrhosis is associated with hepatopulmonary syndrome (HPS), which is related to increased posttransplant morbidity and mortality. AIMS: This study aims to analyze the pathophysiology of biliary cirrhosis and the onset of HPS. METHODS: Twenty-one-day-old Wistar rats were subjected to common bile duct ligation and were allocated to two groups: group A (killed 2, 3, 4, 5, or 6 weeks after biliary obstruction) and group B (subjected to biliodigestive anastomosis 2, 3, 4, 5, or 6 weeks after the first procedure and killed 3 weeks later). At the killing, arterial blood was collected for the analyses, and samples from the liver and lungs were collected for histologic and molecular analyses. The gasometric parameters as well as the expression levels of ET-1, eNOS, and NOS genes in the lung tissue were evaluated. RESULTS: From a total of 42 blood samples, 15 showed hypoxemia (pO2 < 85 mmHg) and 17 showed an increased oxygen gradient [p (A-a) O2 > 18 mmHg]. The liver histology revealed increased ductular proliferation after common bile duct ligation, and reconstruction of bile flow promoted decreased ductular proliferation 5 and 6 weeks post-common bile duct ligation. Pulmonary alterations consisted of decreased parenchymal airspace and increased medial wall thickness. Biliary desobstruction promoted transitory improvements 5 weeks after biliary obstruction (increased parenchymal airspace and decreased MWT-p = 0.003 and p = 0.004, respectively) as well as increased endothelin expression levels (p = 0.009). CONCLUSIONS: The present model showed lung tissue alterations promoted by biliary obstruction. The biliodigestive anastomosis had no clear direct effects on these alterations.

Analysis of the reversibility of biliary cirrhosis in young rats submitted to biliary obstruction.

BACKGROUND/PURPOSE: Biliary atresia and other liver biliary obstructions are relevant conditions in pediatric surgery due to their progression to biliary cirrhosis and indication for liver transplantation. It is known that the period during which biliary obstruction persists determines the development of cirrhosis and its reversibility after a biliary drainage procedure. However, no time or histological markers of biliary cirrhosis reversibility have been established. MATERIALS AND METHODS: One hundred and twenty-nine young Wistar rats underwent surgery for ligation of the common bile duct and were maintained until 8weeks. A part of these animals was submitted to biliary drainage surgery at 2, 3, 4, 5, or 6weeks after the initial procedure. After cyst formation at the site of obstruction, cyst-jejunal anastomosis was performed to restore bile flow. After biliary obstruction and drainage, liver samples were collected for histological and molecular analysis of the genes responsible for collagen deposition and fibrosis. RESULTS: The mortality rates were 39.8% and 56.7% after the first and second procedures, respectively. Ductular proliferation (p=0.001) and collagen deposition increased according to the period under obstruction (p=0.0001), and both alterations were partially reduced after biliary drainage. There were no significant differences in the values of desmin and α-actin according to the period during which the animal remained with biliary obstruction (p=0.09 and p=0.3, respectively), although increased values of transforming growth factor beta 1 (TGFß1) occurred after 8weeks (p=0.000). Desmin levels decreased, and α-actin and TGFß1 levels increased according to the period under obstruction. The molecular alterations were partially reversed after biliary drainage. CONCLUSIONS: The histologic and molecular changes in the liver parenchyma promoted by biliary obstruction in the young animal can be partially reversed by a biliary drainage procedure.