Assessment of Liver Function Using Pharmacokinetic Parameters of Gd-EOB-DTPA: Experimental Study in Rat Hepatectomy Model

Selective HIF stabilization alleviates hepatocellular steatosis and ballooning in a rodent model of 70% liver resection

BACKGROUND

Small-for-size syndrome (SFSS) looms over patients needing liver resection or living-donor transplantation. Hypoxia has been shown to be crucial for the successful outcome of liver resection in the very early postoperative phase. While poorly acceptable as such in real-world clinical practice, hypoxia responses can still be simulated by pharmacologically raising levels of its transducers, the hypoxia-inducible factors (HIFs). We aimed to assess the potential role of a selective inhibitor of HIF degradation in 70% hepatectomy (70%Hx).

METHODS

In a pilot study, we tested the required dose of roxadustat to stabilize liver HIF1α. We then performed 70%Hx in 8-week-old male Lewis rats and administered 25 mg/kg of roxadustat (RXD25) at the end of the procedure. Regeneration was assessed: ki67 and 5-ethynyl-2'-deoxyuridine (EdU) immunofluorescent labeling, and histological parameters. We also assessed liver function via a blood panel and functional gadoxetate-enhanced magnetic resonance imaging (MRI), up to 47 h after the procedure. Metabolic results were analyzed by means of RNA sequencing (RNAseq).

RESULTS

Roxadustat effectively increased early HIF1α transactivity. Liver function did not appear to be improved nor liver regeneration to be accelerated by the experimental compound. However, treated livers showed a mitigation in hepatocellular steatosis and ballooning, known markers of cellular stress after liver resection. RNAseq confirmed that roxadustat unexpectedly increases lipid breakdown and cellular respiration.

CONCLUSIONS

Selective HIF stabilization did not result in an enhanced liver function after standard liver resection, but it induced interesting metabolic changes that are worth studying for their possible role in extended liver resections and fatty liver diseases.

Assessment of liver function reserve by photoacoustic tomography: a feasibility study

Assessment of liver function reserve (LFR) is essential to determine liver resection scope and predict prognosis for patients with liver disease. Indocyanine green (ICG) concentration change is a classic marker to reflect liver function reserve as ICG is selectively taken up and eliminated by liver. Here we proposed a noninvasive approach for LFR assessment based on a real-time photoacoustic tomography (PAT) system. This feasibility study was to detect ICG concentration change by PAT in phantom and in vivo using both normal and partial hepatectomy (PH) rabbits. A linear relationship between photoacoustic signal intensity of ICG and ICG concentration was found in vitro. In vivo ICG concentration change over time after ICG injection was observed by PAT in normal rabbits, which was consistent with the findings measured by invasive spectrophotometry. Finally, clear difference in ICG clearance between the control and PH models was identified by PAT. Taken together, our study indicated the clinical potential of PAT to in vivo evaluate LFR noninvasively.

Metal-Based Complexes as Pharmaceuticals for Molecular Imaging of the Liver

This article reviews the use of metal complexes as contrast agents (CA) and radiopharmaceuticals for the anatomical and functional imaging of the liver. The main focus was on two established imaging modalities: magnetic resonance imaging (MRI) and nuclear medicine, the latter including scintigraphy and positron emission tomography (PET). The review provides an overview on approved pharmaceuticals like Gd-based CA and ^99mTc-based radiometal complexes, and also on novel agents such as ⁶⁸Ga-based PET tracers. Metal complexes are presented by their imaging modality, with subsections focusing on their structure and mode of action. Uptake mechanisms, metabolism, and specificity are presented, in context with advantages and limitations of the diagnostic application and taking into account the respective imaging technique.