Effects of a novel selective PPARα modulator, statin, sodium-glucose cotransporter 2 inhibitor, and combinatorial therapy on the liver and vasculature of medaka nonalcoholic steatohepatitis model.

OBJECTIVE: Nonalcoholic steatohepatitis (NASH) is a disease entity with an increasing incidence, with involvement of several metabolic pathways. Various organs, including the liver, kidneys, and the vasculature, are damaged in NASH, indicating the urgent need to develop a standard therapy. Therefore, this study was conducted to investigate the effects of drugs targeting various metabolic pathways and their combinations on a high-fat diet (HFD)-induced NASH medaka model. METHODS: To investigate the effects of drugs on vascular structures, the NASH animal model was developed using the fli::GFP transgenic medaka fed with HFD at 20 mg/fish daily. The physiological changes, histological changes in the liver, vascular structures in the fin, and serum biochemical markers were evaluated in a time-dependent manner after treatment with selective peroxisome proliferator-activated receptor α modulator (pemafibrate), statin (pitavastatin), sodium-glucose cotransporter 2 inhibitor (tofogliflozin), and their combinations. Furthermore, to determine the mechanisms underlying the effects, whole transcriptome sequencing was conducted using medaka liver samples. RESULTS: Histological analyses revealed significant suppression of fat accumulation and fibrotic changes in the liver after treatment with drugs and their combinations. The expression levels of steatosis- and fibrosis-related genes were modified by the treatments. Moreover, the HFD-induced vascular damages in the fin exhibited milder changes after treatment with the drugs. CONCLUSION: The effects of treating various metabolic pathways on the medaka body, liver, and vascular structures of the NASH medaka model were evidenced. Moreover, to our knowledge, this study is the first to report whole genome sequence and gene expression evaluation of medaka livers, which could be helpful in clarifying the molecular mechanisms of drugs.

Inhibition of sodium-glucose cotransporter 2 ameliorates renal injury in a novel medaka model of nonalcoholic steatohepatitis-related kidney disease.

The effect of sodium-glucose cotransporter 2 inhibitor (SGLT2I) on nonalcoholic steatohepatitis (NASH) has been reported, but there are few studies on its effect on NASH-related renal injury. In this study, we examined the effect of SGLT2I using a novel medaka fish model of NASH-related kidney disease, which was developed by feeding the d-rR/Tokyo strain a high-fat diet. SGLT2I was administered by dissolving it in water of the feeding tank. SGLT2I ameliorates macrophage accumulation and oxidative stress and maintained mitochondrial function in the kidney. The results demonstrate the effect of SGLT2I on NASH-related renal injury and the usefulness of this novel animal model for research into NASH-related complications.

Effective prevention of sorafenib-related vascular damage induced adverse events and maintenance of hepatic function by dried bonito broth and histidine.

Background: Sorafenib (SOR) is an anti-angiogenic chemotherapeutic that prolongs the survival rates of patients with hepatocellular carcinoma. However, SOR also damages normal vasculature and causes associated adverse events, including hand-foot syndrome and hypertension (HT). We previously reported in an animal study that vascular damage resulted in the narrowing of the normal vascular dimension area in medaka fish (Oryzias), and histidine (HIS), a major amino acid contained in dried bonito broth (DBB), prevented these changes. Therefore, in the study, we analyzed the effects of DBB and HIS on SOR-related vascular damages and associated adverse events in patients. Materials and methods: Three-dimensional (3D) vascular images of abdominal regions reconstituted from computed tomography were assessed to compare vascular diameter prior to and following SOR administration in groups receiving SOR monotherapy, DBB+SOR, and HIS+SOR. The clinical courses of hand-foot syndrome and HT and the toxicities of SOR in biochemical assays were monitored and compared between the groups. Correlations between hepatic function and SOR-related changes in the portal venous area dimension were also assessed. Results: SOR-related vascular damage revealed narrowing of the normal abdominal vasculature in the human body, which was monitored using 3D images. The damage was ameliorated by DBB and HIS, however, HIS had a more marked effect, particularly on the renal arteries and portal vein (PV). Maintenance of blood flow contributed to the maintenance of total cholesterol, prothrombin time, albumin (ALB), and renal functions. Changes in the 3D vascular area dimension of the PV and level of serum ALB were significantly correlated. The occurrences of the clinical symptoms of hand-foot syndrome and HT were lower in the DBB- and HIS-treated groups. Conclusion: Our results clearly demonstrate that DBB and HIS prevented SOR-related abdominal vascular damage and effectively maintained hepatic function, and prevented clinical symptoms and toxicity. Trial registration: This study was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000025937 and UMIN000026898).

Inhibition of sodium glucose cotransporter 2 (SGLT2) delays liver fibrosis in a medaka model of nonalcoholic steatohepatitis (NASH).

The rise in the incidence of nonalcoholic steatohepatitis (NASH) has necessitated the development of an effective prevention methodology. An antidiabetic drug, belonging to the group of sodium glucose cotransporter 2 (SGLT2) inhibitors, has been tested for its therapeutic effect on NASH; however, no studies to date have demonstrated the preventive effect of an SGLT2 inhibitor on the histological progression of steatosis and fibrosis in a sequential manner in animal models. In the present study, we examined the effect of the SGLT2 inhibitor, tofogliflozin (Tofo), on NASH liver tissue using medaka as an animal model, maintaining a feeding amount and drug concentration in all animal bodies. We generated a medaka NASH model by feeding d-rR/Tokyo medaka a high-fat diet and administered Tofo by dissolving the drug directly in the water of the feeding tank. Thereafter, the effects of Tofo on body weight (BW), liver weight, hepatotoxicity, fatty infiltration, and fibrotic changes in the liver were examined. We report here that SGLT2 is expressed in medaka fish and that Tofo inhibits the accumulation of fatty tissue and delays the progression of liver fibrosis in the medaka NASH model by inhibiting increases in blood sugar, serum lipids, and transaminase, irrespective of changes in BW. These results suggest that Tofo is effective for treating NASH and that the medaka model may be useful for developing new therapeutic drugs for this disease.

Effective prevention of sorafenib-induced hand-foot syndrome by dried-bonito broth.

BACKGROUND: Sorafenib (SOR) is a molecular medicine that prolongs the survival of patients with hepatocellular carcinoma (HCC). Therefore, the management of side effects is essential for the longer period of continuous medication. Among the various side effects, hand-foot syndrome (HFS) is the most common, occurring in 30%-50% of patients, and often results in discontinuation of the SOR medication. However, its mechanism has not been clarified, and no effective prevention method has been reported for the symptoms. Therefore, this study aimed to analyze its mechanism and to develop an effective prevention regimen for the symptoms. MATERIALS AND METHODS: To assess the mechanism of SOR-induced HFS, the peripheral blood flow in the hand and foot was carefully monitored by Doppler ultrasound, thermography, and laser speckle flowgraphy in the cases treated with SOR and its contribution was assessed. Then, the effect of dried-bonito broth (DBB), which was reported to improve peripheral blood flow, on the prevention of the symptom was examined by monitoring its occurrence and the peripheral blood flow. RESULTS: A total of 25 patients were enrolled in this study. In all, eight patients developed HFS, and all cases showed a significant decrease in the peripheral blood flow. DBB contributed to an increase in the flow (p = 0.009) and significantly decreased occurrence of HFS (p = 0.005) than control. Multivariable analysis showed that the ingestion of DBB is a significant independent contributor to HFS-free survival period (p = 0.035). CONCLUSION: The mechanism of SOR-induced HFS involves a decrease in the peripheral blood flow, and the ingestion of DBB effectively prevents the development of the syndrome by maintaining the flow.

Effect of a neural relay on liver regeneration in mice: activation of serotonin release from the gastrointestinal tract.

The development of therapeutic options to promote hepatic regeneration following severe liver injury is essential. While humoral factors have been reported as mechanisms of liver regeneration, the contributions of interorgan communication to liver regeneration have not been reported. In this study, we examined the effect of a neural relay on liver regeneration via activation of serotonin release from the gastrointestinal (GI) tract. Our results demonstrated that the afferent visceral nerve from the liver activates the efferent vagus nerve from the brain, leading to activation of serotonin release from the GI tract and contributing to liver regeneration. While it is difficult to apply these results directly to human health, we believe that this study may represent a step toward developing essential therapeutics to promote liver regeneration.

Effect of histidine on sorafenib-induced vascular damage: Analysis using novel medaka fish model.

BACKGROUND: Sorafenib (SFN) is an anti-angiogenic chemotherapeutic that prolongs survival of patients with hepatocellular carcinoma (HCC); its side effects, including vascular damages such as hand-foot syndrome (HFS), are a major cause of therapy discontinuation. We previously reported that maintenance of peripheral blood flow by intake of dried bonito broth (DBB) significantly prevented HFS and prolonged the administration period. The amino acids contained in DBB probably contribute to its effects, but the mechanism has not been clarified. We hypothesized that histidine, the largest component among the amino acids contained in DBB, has effects on SFN-induced vascular damage, and evaluated this possibility using a novel medaka fish model. METHODS: The fli::GFP transgenic medaka fish model has a fluorescently visible systemic vasculature. We fed the fish with SFN with and without histidine to compare blood flow and vascular structure among the differently fed models. The vascular cross-sectional area of each fish was measured to determine vascular diameter changes. RESULTS: Our results demonstrated that SFN-fed medaka developed a narrower vascular diameter. In addition, this narrowing was counteracted by addition of histidine to the medaka diet. We observed no positive effect of histidine on regeneration of cut vessels or on cell growth of endothelial cells and HCC cell lines. CONCLUSION: We proved the efficacy of the medaka model to assess vascular changes after administration of specific chemicals. And our results suggest that SFN causes vascular damage by narrowing peripheral vessel diameter, and that histidine effectively counteracts these changes to maintain blood flow.

Effects of Fibrotic Tissue on Liver-targeted Hydrodynamic Gene Delivery.

Hydrodynamic gene delivery is a common method for gene transfer to the liver of small animals, and its clinical applicability in large animals has been demonstrated. Previous studies focused on functional analyses of therapeutic genes in animals with normal livers and little, however, is known regarding its effectiveness and safety in animals with liver fibrosis. Therefore, this study aimed to examine the effects of liver fibrosis on hydrodynamic gene delivery efficiency using a rat liver fibrosis model. We demonstrated for the first time, using pCMV-Luc plasmid, that this procedure is safe and that the amount of fibrotic tissue in the liver decreases gene delivery efficiency, resulting in decrease in luciferase activity depending on the volume of fibrotic tissue in the liver and the number of hepatocytes that are immunohistochemically stained positive for transgene product. We further demonstrate that antifibrotic gene therapy with matrix metalloproteinase-13 gene reduces liver fibrosis and improves efficiency of hydrodynamic gene delivery. These results demonstrate the negative effects of fibrotic tissue on hydrodynamic gene delivery and its recovery by appropriate antifibrotic therapy.