NAFLD and Hepatocellular Carcinoma: How Big a Problem is This Really?

PBPK modeling of impact of nonalcoholic fatty liver disease on toxicokinetics of perchloroethylene in mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD), a major cause of chronic liver disease in the Western countries with increasing prevalence worldwide, may substantially affect chemical toxicokinetics and thereby modulate chemical toxicity.

OBJECTIVES

This study aims to use physiologically-based pharmacokinetic (PBPK) modeling to characterize the impact of NAFLD on toxicokinetics of perchloroethylene (perc).

METHODS

Quantitative measures of physiological and biochemical changes associated with the presence of NAFLD induced by high-fat or methionine/choline-deficient diets in C57B1/6 J mice are incorporated into a previously developed PBPK model for perc and its oxidative and conjugative metabolites. Impacts on liver fat and volume, as well as blood:air and liver:air partition coefficients, are incorporated into the model. Hierarchical Bayesian population analysis using Markov chain Monte Carlo simulation is conducted to characterize uncertainty, as well as disease-induced variability in toxicokinetics.

RESULTS

NAFLD has a major effect on toxicokinetics of perc, with greater oxidative and lower conjugative metabolism as compared to healthy mice. The NAFLD-updated PBPK model accurately predicts in vivo metabolism of perc through oxidative and conjugative pathways in all tissues across disease states and strains, but underestimated parent compound concentrations in blood and liver of NAFLD mice.

CONCLUSIONS

We demonstrate the application of PBPK modeling to predict the effects of pre-existing disease conditions as a variability factor in perc metabolism. These results suggest that non-genetic factors such as diet and pre-existing disease can be as influential as genetic factors in altering toxicokinetics of perc, and thus are likely contribute substantially to population variation in its adverse effects.

Actein ameliorates hepatic steatosis and fibrosis in high fat diet-induced NAFLD by regulation of insulin and leptin resistant

Insulin and leptin resistance are highly involved in metabolic syndrome and non-alcoholic fatty liver disease (NAFLD). Presently, no approved treatment is available. Actein is isolated from the rthizomes of Cimicifuga foetida, a triterpene glycoside, exhibiting important biological properties, such as anti-inflammatory, anti-cancer, and anti-oxidant activity. However, its effects on metabolic syndrome are poorly understood. The aims of the study were mainly to investigate the molecular mechanisms regulating insulin and leptin resistance, and lipogenic action of actein in high fat diet-fed mice. Our data indicated that actein-treated mice displayed lower body weight, epididymal and subcutaneous fat mass, as well as serum lipid levels. Also, improved insulin and leptin resistance were observed in actein-treated groups. Liver inflammation and fibrosis triggered by high fat diet were decreased for actein administration. Moreover, hepatic lipid accumulation was also reduced by actein along with reductions of hepatic de novo lipogenesis-linked signals in actein-treated rodents with high fat diet. High fat diet-induced activation of insulin receptor substrate 1/Forkhead box protein O1 (IRS1/FOXO1), Janus kinase 2 gene/signal transducer and activator of transcription (JAK2/STAT3) and Protein Kinase B/Glycogen synthase kinase 3 beta (AKT/GSK3β) pathways in liver was inhibited by actein, a potential mechanism by which hyperinsulinemia, hyperleptindemia and dyslipidemia were attenuated. Thus, the findings above might be of nutritional and therapeutic importance for the treatment of NAFLD.

Non-alcoholic fatty liver disease, to struggle with the strangle: Oxygen availability in fatty livers

Nonalcoholic fatty liver diseases (NAFLD) is one of the most common chronic liver disease in Western countries. Oxygen is a central component of the cellular microenvironment, which participate in the regulation of cell survival, differentiation, functions and energy metabolism. Accordingly, sufficient oxygen supply is an important factor for tissue durability, mainly in highly metabolic tissues, such as the liver. Accumulating evidence from the past few decades provides strong support for the existence of interruptions in oxygen availability in fatty livers. This outcome may be the consequence of both, impaired systemic microcirculation and cellular membrane modifications which occur under steatotic conditions. This review summarizes current knowledge regarding the main factors which can affect oxygen supply in fatty liver.