MICRO-CT CONTRAST AGENTS FOR DETECTION OF MURINE NON-ALCOHOLIC FATTY LIVER DISEASE
Author: Stephen Marchant / Company: MediLumine inc. / C.I. 2794081
Presentation: Friday, September 15th, 2017 / Exhibit Stage / 10h28 AM

RATIONALE AND AIM
Contrast enhanced micro-computed tomography (micro-CT) represents a potential technique for detection and staging progression of murine non-alcoholic fatty liver disease (NAFLD). One objective of this study was to compare Mvivo™ BIS and Fenestra® LC
X-ray contrast agents in their ability to detect fatty liver disease ina non-alcoholic steatohepatitis (NASH) mouse model. It was hypothesized that liver of NASH mice should have a compromised micro-CT enhancement profile compared to normal mice.
Mvivo™ BIS bismuth(III) oxide
Mvivo™ BIS bismuth(III) oxide nanoparticles are used for anatomical micro-CT imaging of liver and spleen.1 The nanoparticles have a size of 300 nanometers and do not pass through fenestrae of liver sinusoids which have a size under 200 nanometers.
Mvivo™ BIS nanoparticles are instantaneously taken up by kupffer cells in liver after tail vein IVinjection and can be used foranatomical liver imaging since
15% murine liver is composedof kupffer cells.2 The starch covered nanoparticles are composed of BIS bismuth(III) oxide Sinusoidal blood vessel of a rat liver with fenestrated
cells. These fenestrae in Sprague Dawley
and can be administered at very endothelial
rats and C57BL/6 mice have an approximate size ofand 140 nm respectively. Image courtesy of Prof.
low doses due the high X-ray at- 160
Robin Fraser, University of Otago, NZ.
tenuation coefficient of bismuth.
Figure 1: Axial view (left) and coronal view (right) of micro-CT anatomical images representing liver andspleen (coronal) 20 minutes after injection of Mvivo™ BIS (IV dose of 1 ml/kg) in normal C57Bl/6 mouse.

Fenestra® LCFenestra® LC contrast agent is an oil-in-water emulsion used
for anatomical and functional imaging of liver. The emulsion contains lipomimetic iodinated triglycerides (ITG).
The lipid spheres of Fenestra® LC nanoemulsion act as the deli-very vehicle for ITG and have an average size under 150 nanometers which allows them to pass through fenestrae of liver sinusoids and access hepatocytes. It is thought that the lipid spheres
mimic chylomicron remnants by incorporating apoliporotein
E (APO-E) from plasma for selective targeting of hepatocytes.
Fenestra® LC can be used for functional imaging of liver since thebiomimetic targeting, endocytosis, metabolism and elimination oftriglycerides in the emulsion depends on intracellular and extracellular liver lipase catalysis and other functional metabolic processesof healthy liver.3 In healthy mice, 70% of the total Fenestra® LC doseis localized to hepatocytes as soon as 30 minutes after IV administration.3 The Fenestra® LC nanoemulsion remains in organism for up to
24 hours before being eventually eliminated by hepatobiliary system.
Figure 2: Axial view (left) and coronal view (right) of micro-CT images representing liver and spleen (coronalview) 24 hours after injection of Fenestra® LC (IV dose of 6 ml/kg) in normal C57Bl/6 mouse.

RESULTS
In normal mice, both Fenestra® LC and Mvivo™ BIS provide micro-CT contrast enhancement in the mouse liver and the abilityto delineate liver blood vessels through a negative contrast enhancement effect. In healthy mice, Mvivo™ BIS provides a stronger spleenic and spleen to liver CT enhancement ratio compared
to Fenestra® LC (Fig. 1,2). With Fenestra® LC, the contrast agent
remained in liver blood vessels 24 hours after injection in NASH
mice suggesting that the hepatobiliary system of the compromised NASH mouse liver could not take up the triglycerides of theFenestra emulsion (Fig. 3). Injection of Mvivo™ BIS in NASH miceprovides contrast enhancement in spleen and gives non-uniform
contrast enhancement in liver suggesting that the contrast agent
can be used for monitoring changes in anatomy of liver RES compartment during progression of fatty liver disease. Further work
will need to be done to determine if these contrast agents can beused for early detection and monitoring the progression of NAFLD.
Figures 3: Axial view (left) and coronal view (right) of micro-CT images representing liver blood vessels
24 hours after injection of Fenestra® LC at an IV dose of 6 ml/kg in NASH induced C57Bl/6 mice.

METHODS
Animals we’re provided by laboratory of Prof. Dr. med Ulf PeterNeumann at the clinic for general, visceral and transplant surgery at the University of Aachen. To induce NASH, C57BL/6 neonatal
mice were fed a high-fat, high fructose and high-cholesterine diet(western diet) for 30 weeks alongside control mice of same ageand sex. Micro-CT measurements were obtained using a dual energy gantry-based flat-panel micro-computed tomography scanner (TomoScope 30s Duo; CT Imaging, Erlangen, Germany) in thelaboratory of Prof. Twan Lammers at the Institute for Experimental Molecular Imaging at RWTH Aachen University. The dual-energy X-ray tubes of the micro-CT were operated at voltages of 40
and 65 kV with currents of 1.0 and 0.5 mA. Mvivo™ BIS contrast
agent was administered at a dose of 1 ml per kg via tail vein IV injection followed by acquisition of microCT measurements 20 minutes post injection in both control and NASH mice. Fenestra® LCwas administered at a dose of 6 ml per kg with tail vein IV injection
followed by acquisition of microCT images 24 hours post injection
in both control and NASH mice.

Figures 4: Axial view (left) and coronal view (right) of liver and spleen (coronal view) representing RES
compartments 20 minutes after IV injection of Mvivo™ BIS.

REFERENCES
1. Romere C, et al. Cell. 2016 Apr 21; 165(3): 566–579.
2. Sitia G , et al. PLoS Pathog. 2011 Jun;7(6):e1002061.
3. Bakan DA, Weichert JP, Longino MA, Counsell RE. Invest. Radiol. 2000; 35:158.

ACKNOWLEDGEMENTS
Prof. Twan Lammers and Diana Möckel at the Institute for Experimental Molecular Imaging atRWTH Aachen University