In Vivo Visualization and Quantification of (Disturbed) Oatp-Mediated Hepatic Uptake and Mrp2-Mediated Biliary Excretion of ^99mTc-Mebrofenin in Mice

Abstract

Hepatic transport of 99m Tc-mebrofenin through organic anion transport protein 1a and 1b (Oatp1a/1b) and multidrug resistance protein 2 (Mrp2) was investigated by small-animal SPECT. On the basis of the results, a noninvasive method to visualize and quantify disturbances in hepatic transport is proposed. Methods: Friend virus B wild-type mice (untreated, bile ductligated, vehicle-or rifampicin-treated) and strain-matched knockout mice unable to express the uptake transporters Oatp1a/1b (Slco1a/1b 2/2 / 2/2 ) or the efflux transporter Mrp2 (Abcc2 2/2 ) were intravenously injected with 99m Tc-mebrofenin (n 5 3 per group). After dynamic small-animal SPECT and short CT acquisitions, time-activity curves of the liver and of the gallbladder and intestines were obtained and correlated with direct blood samples. Results: Normal hepatobiliary clearance of 99m Tcmebrofenin was severely impaired in the bile duct-ligated animal, as evidenced by elevated hepatic tracer levels. In Slco1a/ 1b 2/2 / 2/2 mice, a lower area under the curve (AUC) for the liver (P 5 0.014) was obtained and no activity was detected in the gallbladder and intestines. Renal rerouting was observed, along with an increase in the blood AUC (P 5 0.01). Abcc2 2/2 mice had a higher liver AUC (P 5 0.009), a delayed emergence time of 99m Tc-mebrofenin in the gallbladder (P 5 0.009), and a lower AUC for the gallbladder and intestines (P 5 0.001). The blood curve was similar to that of wild-type mice. 99m Tc-mebrofenin disposition was altered after rifampicin treatments. We observed a dose-dependent delayed time point at which tracer maximized in liver, an increased AUC for liver, and a lower AUC for gallbladder and intestines (P 5 0.042, 0.034, and 0.001, respectively, highest dose). Emergence in the gallbladder occurred later (P 5 0.009, highest dose), and blood AUC was higher (P 5 0.006). Conclusion: The current study visualized and quantified hepatic uptake and biliary efflux of 99m Tc-mebrofenin. Our results demonstrated the possibility of discriminating, on a quantitative level, between lack of functional activity of sinusoidal uptake versus that of biliary efflux transporters.

Evidence of Drug-Drug Interactions through Uptake and Efflux Transport Systems in Rat Hepatocytes: Implications for Cellular Concentrations of Competing Drugs

“…The cellular mechanisms of cholestasis associate interactions with drug uptake in mice (van de Steeg et al, 2010;Neyt et al, 2013) as well as decrease bile excretion through Mrp2 in mice (Neyt et al, 2013) and human bile salt export pump in transfected cells (Mita et al, 2006). However, RIF has also beneficial effects in cholestatic liver diseases; chronic treatment with RIF enhances bile acid detoxification, bilirubin conjugation, and excretion in association with an increased hepatic expression of CYP3A4, UGT1A1, and MRP2 (Marschall et al, 2005).…”

Lycopene treatment stalls the onset of experimentally induced hepatocellular carcinoma: a radioisotopic, physiological and biochemical analysis

“…The delay in hepatic uptake in NDEA animals may be due to severe hepatocellular dysfunction. Neyt et al [34] have also reported the delayed uptake due to the dysfunction of various Oatp transporters located on hepatocytes. The retention of radiotracer activity in the liver of NDEA mice up to 60 min showed marked impairment in the excretion of the activity.…”

The Role of Organic Anion Transporters in Diagnosing Liver Diseases by Magnetic Resonance Imaging

“…In contrast, erythromycin treatment has no effect on clinical liver MRI with EOB-DTPA, but no other potentially competing drugs were investigated (Huppertz et al, 2011). In rodents, rifampicin administration blocks the rMRP2 and increases the hepatic accumulation of the SPECT tracer 99m Tc-mebrofenin (Neyt et al, 2013) and the PET tracers 11 C-telmisartan (Takashima et al, 2011) and [11C] TIC-Me (Kusuhara, 2013). Interaction of ritonavir with 99m Tc-mebrofenin was also recently investigated (Pfeifer et al, 2013).…”