Hyperspectral evaluation of liver oxygenation in a murine model of metabolic associated liver disease and hepatocellular carcinoma

Abstract

Abstract Objective Untreated MAFLD is a continuum of disease ranging from hepatic steatosis to cirrhosis and hepatocellular carcinoma (HCC). Throughout the disease progression, a change in hepatic hemodynamics occurs as portal hypertension. Hepatic arterial buffer response is a compensatory mechanism to maintain liver perfusion facing reduction of portal flow. These changes could also impair hepatic oxygenation homeostasis. The aim of this study is to test this hypothesis in mouse models and to shed light on the oxygenation of fatty, portal hypertensive liver and its impact on HCC carcinogenesis. Methods C57BL/6 mice were fed a HFD starting from 4 weeks of age, porto-systemic shunts (or sham) were created at 8 weeks, and monitored up to 40 weeks. ND-fed non-shunted mice were used as control group. Hyperspectral imaging (HSI) was utilized to quantify tissue oxygenation (StO2) of ND, HFD and HFD-shunted mice. In a second set of experiment, we explored the role of a common hepatic artery ligation in the studied DEN-induced HFD mouse model. Results HFD induced hepatic steatosis and portal pressure compared to ND. Porto-systemic shunt could deviate about 67% of the portal flow through the spleen to the systemic circulation, thus reducing portal pressure close-to-normal levels. Compared to control mice, HFD feeding increased liver oxygenation (p=0.0004), while shunting restored a close to normal level (p<0.001). The oxygenation of small bowel is decreased in a similar manner in both HFD and HFD-shunted mice. In HFD-fed mice, artery ligation led to less carcinogenesis compared to mice without artery ligation (p=0.026). In addition, artery ligation was also associated with smaller HCCs (p=0.027). Conclusion Early stages of MAFLD alter hepatic oxygen homeostasis. Fatty liver, when associated to portal hypertension, express higher liver oxygenation levels, compared to control group. This could due to hepatocyte ballooning with a narrowing of portal system, thus bring portal hypertension state with a simultaneous arterial buffer response. Additionally, small bowel of portal hypertensive mice showed lower oxygen levels mirroring an intestinal venous congestion typical of portal hypertension. Oxygen deprivation, through artery ligation, decreases HCC carcinogenesis and reduces HCC nodules volume. Yet further research is needed but oxygen homeostasis seems play a role in MAFLD progression as well in HCC pathophysiology.