Nonalcoholic fatty liver disease (NAFLD) – Is it a new marker of hyporesponsiveness to recombinant human erythropoietin in patients that are on chronic hemodialysis?

Erythropoietin hyporesponsiveness in non-alcoholic fatty liver disease

Treatment with erythropoietin (EPO) can correct anaemia in chronic kidney disease (CKD) patients; however, up to 10% exhibit resistance or hyporesponsiveness to EPO. Non-alcoholic fatty liver disease (NAFLD), prevalent liver disease in CKD patients, may limit EPO response because of thrombopoietin deficiency, iron homeostasis disorder and inflammation. Therefore, we hypothesized NAFLD is a risk factor for EPO responsiveness. To test our hypothesis, we evaluated the effect of EPO in healthy rats and rats with NAFLD induced by a high-fat, high-carbohydrate (HFHC) diet. After 12 weeks on the HFHC diet, NAFLD rats showed lower erythroid response to EPO treatment than healthy rats. We, then, determined that the primary cause of EPO hyporesponsiveness could be iron deficiency associated with inflammation, which reduces erythroid cell production. Specifically, the concentrations of hepcidin, ferritin, transferrin and white blood cells in NAFLD rats were 12.8-, 16.4-, 2.51- and 1.40-fold higher than those in healthy rats, respectively. However, erythroid cell types in the bone marrow of NAFLD rats were significantly reduced. In conclusion, our data suggest that NAFLD could be a risk factor for EPO responsiveness, which is attributed to functional iron deficiency associated with inflammation.

The traditional Chinese formulae Ling-gui-zhu-gan decoction alleviated non-alcoholic fatty liver disease via inhibiting PPP1R3C mediated molecules

Background

Ling-gui-zhu-gan decoction (LGZG), a classic traditional Chinese medicine formula, has been confirmed to be effective in improving steatosis in non-alcoholic fatty liver disease (NAFLD). However, the mechanism under the efficacy remains unclear. Hence, this study was designed to investigate the mechanisms of LGZG on alleviating steatosis.

Methods

Twenty four rats were randomly divided into three groups: normal group, NAFLD group, fed with high fat diet (HFD) and LGZG group (fed with HFD and supplemented with LGZG). After 4 weeks intervention, blood and liver were collected. Liver steatosis was detected by Oil Red O staining, and blood lipids were biochemically determined. Whole genome genes were detected by RNA-Seq and the significant different genes were verified by RT-qPCR. The protein expression of Protein phosphatase 1 regulatory subunit 3C (PPP1R3C) and key molecules of glycogen and lipid metabolism were measured by western blot. Chromophore substrate methods measured glycogen phosphorylase (GPa) activity and glycogen content.

Results

HFD can markedly induce hepatic steatosis and promote liver triglyceride (TG) and serum cholesterol (CHOL) contents, while liver TG and serum CHOL were both markedly decreased by LGZG treatment for 4 weeks. By RNA sequencing, we found that NAFLD rats showed significantly increase of PPP1R3C expression and LGZG reduced its expression. RT-qPCR and Western blot both verified the alteration of PPP1R3C upon LGZG intervention. LGZG also promoted the activity of glycogen phosphorylase liver type (PYGL) and inhibited the activity of glycogen synthase (GS) in NAFLD rats, resulting in glycogenolysis increase and glycogen synthesis decrease in the liver. By detecting glycogen content, we also found that LGZG reduced hepatic glycogen in NAFLD rats. In addition, we analyzed the key molecules in hepatic de novo lipogenesis and cholesterol synthesis, and indicated that LGZG markedly inhibited the activity of acetyl-CoA carboxylase (ACC), sterol receptor element-binding protein-1c (SREBP-1c) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), resulting in lipid synthesis decrease in the liver.

Conclusion

Our data highlighted the role of PPP1R3C targeting pathways, and found that hepatic glycogen metabolism might be the potential target of LGZG in preventing NAFLD.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2424-1) contains supplementary material, which is available to authorized users.

Novel ultrasound-based methods to assess liver disease: The game has just begun

In the last 10 years the availability of ultrasound elastography allowed to diagnose and stage liver fibrosis in a non-invasive way and changed the clinical practice of hepatology. Newer ultrasound-based techniques to evaluate properties of the liver tissue other than fibrosis are emerging and will lead to a more complete characterization of the full spectrum of diffuse and focal liver disease. Since these methods are currently undergoing validation and go beyond elastography for liver tissue evaluation, they were not included in the recent guidelines regarding elastography issued by the European Federation of Societies in Ultrasound in Medicine and Biology. In this review paper, we outline the major advances in the field of ultrasound for liver applications, with special emphasis on techniques that could soon be part of the future armamentarium of ultrasound specialists devoted to the assessment of liver disease. Specifically, we discuss current and future ultrasound assessment of steatosis, spleen stiffness for portal hypertension, and elastography for the evaluation of focal liver lesions; we also provide a short glimpse into the next generation of ultrasound diagnostic methods.