Chuan-Yi Chien

The specificity and accuracy of 111In-hexavalent lactoside in estimating liver reserve and its threshold value for mortality in mice

BACKGROUND & AIMS The asialoglycoprotein receptor on hepatocyte membranes recognizes the galactose residues of glycoproteins. We investigated the specificity, accuracy and threshold value of asialoglycoprotein receptor imaging for estimating liver reserve via scintigraphy using (111)In-hexavalent lactoside in mouse models. METHODS (111)In-hexavalent lactoside scintigraphy for asialoglycoprotein receptor imaging was performed on groups of normal mice, orthotopic SK-HEP-1-bearing mice, subcutaneous HepG2-bearing mice, mice with 20-80% partial hepatectomy and mice with acute hepatitis induced by acetaminophen. Liver reserve was measured by relative liver uptake and compared with normal mice. Asialoglycoprotein receptor blockade was performed via an in vivo asialofetuin competitive binding assay. RESULTS A total of 73.64±7.11% of the injection dose accumulated in the normal liver tissue region, and radioactivity was barely detected in the hepatoma region. When asialoglycoprotein receptor was blocked using asialofetuin, less than 0.41±0.04% of the injection dose was detected as background in the liver. Asialoglycoprotein receptor imaging data revealed a linear correlation between (111)In-hexavalent lactoside binding and residual liver mass (R(2)=0.8548) in 20-80% of partially hepatectomized mice, demonstrating the accuracy of (111)In-hexavalent lactoside imaging for measuring the functional liver mass. Asialoglycoprotein receptor imaging data in mice with liver failure induced using 600mg/kg acetaminophen revealed 19-45% liver reserve relative to normal mice and a fatal threshold value of 25% liver reserve. CONCLUSION The (111)In-hexavalent lactoside imaging method appears to be a good, specific, visual and quantitative predictor of functional liver reserve. The diagnostic threshold for survival was at 25% liver reserve in mice.

Use of 111In-Hexavalent Lactoside for Liver Reserve Estimation in Rodents with Thioacetamide-Induced Hepatic Fibrosis

Many biochemical tests detecting the presence of liver disease are not liver-specific and may be abnormal in nonhepatic conditions. The asialoglycoprotein receptor (ASGPR) is a hepatocyte-specific receptor for Gal/GalNAc-terminated glycopeptide or glycoprotein. The number of these receptors decreases in patients with chronic liver diseases. Here, we aimed to evaluate the use of 111In-hexavalent lactoside, a known ASGPR imaging biomarker, as a more sensitive probe to detect small changes in liver reserve in animal models of chronic liver injury. Thioacetamide (TAA) treatment via intraperitoneal injection every 2 days in BALB/c mice continued for 1, 2, 3, or 4 months. The liver fibrosis stages were determined by Sirius Red staining and were based on the METAVIR classification method. Serum transaminase enzymes (alanine transaminase (ALT) and aspartate transaminase (AST)), alkaline phosphatase, albumin, and bilirubin were measured using a FUJI FDC3500 i/s analyzer. The ASGPR staining was performed by immunohistocytochemical stain. The percentages of fibrosis and ASGPR were calculated using ImageJ software after collagen staining and anti-ASGPR staining, respectively. A nanoSPECT/CT was used for molecular imaging and liver uptake measurement. We observed fibrosis grades of F0-F1 in mice treated with TAA for 1 month, F2 in mice treated for 2 months, F3-F4 in mice treated for 3 months, and F4 in mice treated for 4 months. The levels of ALT and albumin were not significantly different in the TAA groups from those in the controls. Although the average levels of AST, alkaline phosphatase, and bilirubin in the TAA groups were different from those in the control group, there was little difference between TAA groups. More sensitive distinctions among TAA groups were detected in 111In-hexavalent lactoside uptake of ASGPR, ASGPR staining, and fibrosis % than when using the conventional AST, ALT, albumin, alkaline phosphatase, and bilirubin tests. The absorption and distribution of 111In-hexavalent lactoside were lower in the chronic hepatitis models than the normal controls. The liver reserves measured by 111In-hexavalent lactoside uptake were 71.7 ± 7.5% and 50.9 ± 5.6% after 1 and 2 months, respectively, of TAA treatment. As an ASGPR biomarker, 111In-hexavalent lactoside has higher sensitivity than traditional liver function tests and collagen stain to provide more objective data for evaluating compensated cirrhosis or changes in liver damage. ASGPR staining can reflect the regenerated hepatocytes, but the need for a biopsy limits its use. 111In-hexavalent lactoside measurement is comparable with ASGPR staining, which suggests that 111In-hexavalent lactoside measurement will be more useful as a practical, noninvasive test of chronic liver injury.