Pitavastatin inhibits hepatic steatosis and fibrosis in non-alcoholic steatohepatitis model rats

Nrf2/HO-1, NF-κB and PI3K/Akt signalling pathways decipher the therapeutic mechanism of pitavastatin in early phase liver fibrosis in rats

Liver fibrosis is a common chronic hepatic disease. This study aimed to investigate the effect of pitavastatin (Pit) against thioacetamide (TAA)-induced liver fibrosis. Rats were divided into four groups: (1) control group; (2) TAA group (100 mg/kg, i.p.) three times weekly for 2 weeks; (3 and 4) TAA/Pit-treated group, in which Pit was administered orally (0.4 and 0.8 mg/kg/day) for 2 weeks following TAA injections. TAA caused liver damage manifested by elevated serum transaminases, reduced albumin and histological alterations. Hepatic malondialdehyde (MDA) was increased, and glutathione (GSH) and superoxide dismutase (SOD) were decreased in TAA-administered rats. TAA upregulated the inflammatory markers NF-κB, NF-κB p65, TNF-α and IL-6. Treatment with Pit ameliorated serum transaminases, elevated serum albumin and prevented histopathological changes in TAA-intoxicated rats. Pit suppressed MDA, NF-κB, NF-κB p65, the inflammatory cytokines and PI3K mRNA in TAA-intoxicated rats. In addition, Pit enhanced hepatic antioxidants and boosted the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) mRNA. Moreover, immunohistological studies supported the ability of Pit to reduce liver fibrosis via suppressing p-AKT expression. In conclusion, Pit effectively prevents TAA-induced liver fibrosis by attenuating oxidative stress and the inflammatory response. The hepatoprotective efficacy of Pit was associated with the upregulation of Nrf2/HO-1 and downregulation of NF-κB and PI3K/Akt signalling pathways.

Anti-fibrotic effects of statin drugs: a review of evidence and mechanisms

Fibrosis is a pathological repair process common among organs, that responds to damage by replacement of tissue with non-functional connective tissue. Despite the widespread prevalence of tissue fibrosis, manifesting in numerous disease states across myriad organs, therapeutic modalities to prevent or alleviate fibrosis are severely lacking in quantity and efficacy. Alongside development of new drugs, repurposing of existing drugs may be a complementary strategy to elect anti-fibrotic compounds for pharmacologic treatment of tissue fibrosis. Drug repurposing can provide key advantages to de novo drug discovery, harnessing the benefits of previously elucidated mechanisms of action and already existing pharmacokinetic profiles. One class of drugs a wealth of clinical data and extensively studied safety profiles is the statins, a class of antilipidemic drugs widely prescribed for hypercholesterolemia. In addition to these widely utilized lipid-lowering effects, increasing data from cellular, pre-clinical mammalian, and clinical human studies have also demonstrated that statins are able to alleviate tissue fibrosis originating from a variety of pathological insults via lesser-studied, pleiotropic effects of these drugs. Here we review literature demonstrating evidence for direct effects of statins antagonistic to fibrosis, as well as much of the available mechanistic data underlying these effects. A more complete understanding of the anti-fibrotic effects of statins may enable a clearer picture of their anti-fibrotic potential for various clinical indications. Additionally, more lucid comprehension of the mechanisms by which statins exert anti-fibrotic effects may aid in development of novel therapeutic agents that target similar pathways but with greater specificity or efficacy.

Changes in Lipidomics, Metabolomics, and the Gut Microbiota in CDAA-Induced NAFLD Mice after Polyene Phosphatidylcholine Treatment

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in most parts of the world. Although there is no first-line drug approved for the treatment of NAFLD, polyene phosphatidylcholine (PPC) is used by clinicians to treat NAFLD patients. This study aimed to evaluate the efficacy of PPC on a mice model of NAFLD, and to study the PPC's mechanism of action. The mice were fed a choline-deficient, L-amino acid-defined (CDAA) diet to induce NAFLD and were subsequently treated with PPC. The treatment effects were evaluated by the liver index, histopathological examination, and routine blood chemistry analyses. Lipidomics and metabolomics analyses of 54 samples were carried out using ultraperformance liquid chromatography (UPLC) coupled to a mass spectrometer to select for changes in metabolites associated with CDAA diet-induced NAFLD and the effects of PPC treatment. The intestinal flora of mice were extracted for gene sequencing to find differences before and after the induction of NAFLD and PPC treatment. PPC significantly improved the CDAA diet-induced NAFLD condition in mice. A total of 19 metabolites including 5 polar metabolites and 14 lipids showed marked changes. In addition, significant differences in the abundance of Lactobacillus were associated with NAFLD. We inferred that the protective therapeutic effect of PPC on the liver was related to the supplement of phosphatidylcholine, lysophosphatidylcholine, and sphingomyelin (PC, LPC, and SM, resectively) and acylcarnitine metabolism. This study developed a methodology for exploring the pathogenesis of NAFLD and can be extended to other therapeutic agents for treating NAFLD.

Improved anti-fibrotic effects by combined treatments of simvastatin and NS-398 in experimental liver fibrosis models

BACKGROUND/AIMS

Efficient anti-fibrotic therapies are required for the treatment of liver cirrhosis. Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) and cyclooxygenase-2 (COX-2) inhibitors have been reported to have anti-fibrotic effects. Here, we investigated whether combined treatment with a statin and a COX-2 inhibitor has synergistic anti-fibrotic effects.

METHODS

The effects of treatment strategies incorporating both simvastatin and a COX-2 inhibitor, NS-398, were investigated using an immortalized human hepatic stellate cell line (LX-2) and a hepatic fibrosis mouse model developed using thioacetamide (TAA) in drinking water. Cellular proliferation was investigated via 5-bromo-2-deoxyuridine uptake. Pro- and anti-apoptotic factors were investigated through Western blotting and real-time polymerase chain reaction analysis.

RESULTS

The evaluation of the anti-proliferative effects on LX-2 cells showed that the observed effects were more pronounced with combination therapy than with single-drug therapy. Moreover, hepatic fibrosis and collagen deposition decreased significantly in TAA-treated mice in response to the combined treatment strategy. The mechanisms underlying the anti-fibrotic effects of the combination therapy were investigated. The effects of the combination therapy were correlated with increased expression levels of extracellular signal-regulated kinase 1/2 signaling molecules, upregulation of the Bax/Bcl-2 signaling pathway, inhibition of the transforming growth factor-β signaling pathway, and inhibition of tissue inhibitor of matrix metalloproteinases 1 and 2.

CONCLUSION

The combination of simvastatin and NS-398 resulted in a synergistic anti-fibrotic effect through multiple pathways. These findings offer a theoretical insight into the possible clinical application of this strategy for the treatment of advanced liver diseases with hepatic fibrosis.

A comprehensive review on the lipid and pleiotropic effects of pitavastatin

The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, or statins, are administered as first line therapy for hypercholesterolemia, both in primary and secondary prevention. There is a growing body of evidence showing that beyond their lipid-lowering effect, statins have a number of additional beneficial properties. Pitavastatin is a unique lipophilic statin with a strong effect on lowering plasma total cholesterol and triacylglycerol. It has been reported to have pleiotropic effects such as decreasing inflammation and oxidative stress, regulating angiogenesis and osteogenesis, improving endothelial function and arterial stiffness, and reducing tumor progression. Based on the available studies considering the risk of statin-associated muscle symptoms it seems to be also the safest statin. The unique lipid and non-lipid effects of pitavastatin make this molecule a particularly interesting option for the management of different human diseases. In this review, we first summarized the lipid effects of pitavastatin and then strive to unravel the diverse pleiotropic effects of this molecule.

Atorvastatin Modulates Bile Acid Homeostasis in Mice with Diet-Induced Nonalcoholic Steatohepatitis

Bile acids (BA) play a significant role in the pathophysiology of nonalcoholic steatohepatitis (NASH). The present study evaluates the modulation of bile acid metabolomics by atorvastatin, a cholesterol-lowering agent commonly used to treat cardiovascular complications accompanying NASH. NASH was induced in mice by 24 weeks of consuming a high–saturated fat, high-fructose, and high-cholesterol diet (F), with atorvastatin administered orally (20 mg/kg/day) during the last three weeks. Biochemical and histological analyses confirmed the effectiveness of the F diet in inducing NASH. Untreated NASH animals had significantly reduced biliary secretion of BA and increased fecal excretion of BA via decreased apical sodium-dependent bile salt transporter (Asbt)-mediated reabsorption. Atorvastatin decreased liver steatosis and inflammation in NASH animals consistently with a reduction in crucial lipogenic enzyme stearoyl–coenzyme A (CoA) desaturase-1 and nuclear factor kappa light chain enhancer of activated B-cell pro-inflammatory signaling, respectively. In this group, atorvastatin also uniformly enhanced plasma concentration, biliary secretion and fecal excretion of the secondary BA, deoxycholic acid (DCA). However, in the chow diet–fed animals, atorvastatin decreased plasma concentrations of BA, and reduced BA biliary secretions. These changes stemmed primarily from the increased fecal excretion of BA resulting from the reduced Asbt-mediated BA reabsorption in the ileum and suppression of synthesis in the liver. In conclusion, our results reveal that atorvastatin significantly modulates BA metabolomics by altering their intestinal processing and liver synthesis in control and NASH mice.

Lifestyle and Environmental Approaches for the Primary Prevention of Hepatocellular Carcinoma

Patients with chronic liver disease are at increased risk of developing hepatocellular carcinoma (HCC). Most patients diagnosed with HCC have limited treatment options and a poor overall prognosis, with a 5-year survival less than 15%. Preventing the development of HCC represents the most important strategy. However, current guidelines lack specific recommendations for primary prevention. Lifestyle factors may be central in the pathogenesis of HCC, and primary prevention strategies focused on lifestyle modification could represent an important approach to the prevention of HCC. Both experimental and epidemiologic studies have identified promising chemopreventive agents for the primary prevention of HCC.

Effect of Canagliflozin, an SGLT2 Inhibitor, in Comparison with Atorvastatin on Dexamethasone-Induced Hepatic Steatosis in Albino Rats

Background:

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease that is considered the most common liver disease all over the world. It causes metabolic and hepatic damage that can progress to cirrhosis and hepatocellular carcinoma.

Objective:

Our research pointed to study the preventive effects of canagliflozin (CANA) or atorvastatin (ATO) on dexamethasone-induced hepatic steatosis and dyslipidemia.

Methods:

Animals were grouped as; control group; DEX group; ATO/DEX-treated group; CANA/DE-treated group and ATO+CANA/DEX-treated group. Results: Significant elevations in GSH, SOD and CAT activities, while high significant decreases in serum GOT, GPT, ALP, urea, blood glucose, CK-MB, LDH, T.G, T.C, MDA and P.C levels were demonstrated in treated groups as compared to DEX group in the experimental periods. Also, significant reductions in SGPT, SGPT, ALP, CK-MB, LDH, T.C and T.G levels were detected in CANA/DEX group as compared to ATO/DEX group. All these results were confirmed with histopathological findings where the severe damages and fatty degeneration in both kidney and liver tissues developed by dexamethasone administration resolved by administration of atorvastatin alone or better with Canagliflozin.

Conclusion:

These results indicate that canagliflozin was as effective as atorvastatin or combination of both in reducing dyslipidemia and hepatic steatosis. The antioxidant and hypolipidemic effects of canagliflozin may be responsible for the beneficial effects.

An Overview of Lipid Metabolism and Nonalcoholic Fatty Liver Disease

The occurrence of nonalcoholic fatty liver disease (NAFLD) is associated with major abnormalities of hepatic lipid metabolism. We propose that lipid abnormalities directly or indirectly contribute to NAFLD, especially fatty acid accumulation, arachidonic acid metabolic disturbance, and ceramide overload. The effects of lipid intake and accumulation on NAFLD and NAFLD treatment are explained with theoretical and experimental details. Overall, these findings provide further understanding of lipid metabolism in NAFLD and may lead to novel therapies.

APOA-1Milano muteins, orally delivered via genetically modified rice, show anti-atherogenic and anti-inflammatory properties in vitro and in Apoe-/- atherosclerotic mice

BACKGROUND

Atherosclerosis is a slowly progressing, chronic multifactorial disease characterized by the accumulation of lipids, inflammatory cells, and fibrous tissue that drives to the formation of asymmetric focal thickenings in the tunica intima of large and mid-sized arteries. Despite the high therapeutic potential of ApoA-1 proteins, the purification and delivery into the disordered organisms of these drugs is still limited by low efficiency in these processes.

METHODS AND RESULTS

We report here a novel production and delivery system of anti-atherogenic APOA-1Milano muteins (APOA-1M) by means of genetically modified rice plants. APOA-1M, delivered as protein extracts from transgenic rice seeds, significantly reduced macrophage activation and foam cell formation in vitro in oxLDL-loaded THP-1 model. The APOA-1M delivery method and therapeutic efficacy was tested in healthy mice and in Apoe^-/- mice fed with high cholesterol diet (Western Diet, WD). APOA-1M rice milk significantly reduced atherosclerotic plaque size and lipids composition in aortic sinus and aortic arch of WD-fed Apoe^-/- mice as compared to wild type rice milk-treated, WD-fed Apoe^-/- mice. APOA-1M rice milk also significantly reduced macrophage number in liver of WD-fed Apoe^-/- mice as compared to WT rice milk treated mice.

TRANSLATIONAL IMPACT

The delivery of therapeutic APOA-1M full length proteins via oral administration of rice seeds protein extracts (the 'rice milk') to the disordered organism, without any need of purification, might overcome the main APOA1-based therapies' limitations and improve the use of this molecules as therapeutic agents for cardiovascular patients.

The potential role of statins in treating liver disease

Statins are commonly use for the management of dyslipidemia, worldwide. Various studies have demonstrated that statins offer significant reduction in the risk of cardiovascular morbidity and mortality. However, this class of drugs has been implicated in potential liver toxicity, thus has been considered as a 'forbidden-drug' in patients with increased liver enzymes. Areas covered: Studies have shown that statins might offer clinical benefits in the setting of viral hepatitis, progression of cirrhosis, and hepatocellular carcinoma. More importantly, this class of drugs was shown to ameliorate liver histological (in both imaging and biopsy studies) and functional alterations in patients with non-alcoholic fatty liver disease or non-alcoholic steatohepatitis. In addition, two large survival studies have demonstrated reduction in the risk for cardiovascular events with statin use in patients with elevated transaminase levels at baseline. Expert commentary: These benefits were of greater extent compared with patients with normal liver function tests at baseline. However, current international guidelines seem to neglect these findings and are not including statins in the management algorithm of patients with non-alcoholic fatty liver disease or steatohepatitis. Future randomized studies providing biopsy-proven benefits will establish the use of statins in the prevention of cardiovascular events and therapeutic algorithm of these patients.

The use of statins alone, or in combination with pioglitazone and other drugs, for the treatment of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis and related cardiovascular risk. An Expert Panel Statement

Non-alcoholic fatty liver disease (NAFLD), the most common liver disease, is characterized by accumulation of fat (>5% of the liver tissue), in the absence of alcohol abuse or other chronic liver diseases. It is closely related to the epidemic of obesity, metabolic syndrome or type 2 diabetes mellitus (T2DM). NAFLD can cause liver inflammation and progress to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis or hepatocellular cancer (HCC). Nevertheless, cardiovascular disease (CVD) is the most common cause of death in NAFLD/NASH patients. Current guidelines suggest the use of pioglitazone both in patients with T2DM and in those without. The use of statins, though considered safe by the guidelines, have very limited use; only 10% in high CVD risk patients are on statins by tertiary centers in the US. There are data from several animal studies, 5 post hoc analyses of prospective long-term survival studies, and 5 rather small biopsy proven NASH studies, one at baseline and on at the end of the study. All these studies provide data for biochemical and histological improvement of NAFLD/NASH with statins and in the clinical studies large reductions in CVD events in comparison with those also on statins and normal liver. Ezetimibe was also reported to improve NAFLD. Drugs currently in clinical trials seem to have potential for slowing down the evolution of NAFLD and for reducing liver- and CVD-related morbidity and mortality, but it will take time before they are ready to be used in everyday clinical practice. The suggestion of this Expert Panel is that, pending forthcoming randomized clinical trials, physicians should consider using a PPARgamma agonist, such as pioglitazone, or, statin use in those with NAFLD/NASH at high CVD or HCC risk, alone and/or preferably in combination with each other or with ezetimibe, for the primary or secondary prevention of CVD, and the avoidance of cirrhosis, liver transplantation or HCC, bearing in mind that CVD is the main cause of death in NAFLD/NASH patients.

Atorvastatin and fluvastatin are associated with dose-dependent reductions in cirrhosis and hepatocellular carcinoma, among patients with hepatitis C virus: Results from ERCHIVES

Statins are associated with delayed fibrosis progression and a reduced risk of hepatocellular carcinoma (HCC) in chronic hepatitis C virus (HCV). Limited data exist regarding the most effective type and dose of statin in this population. We sought to determine the impact of statin type and dose upon fibrosis progression and HCC in patients with HCV. Using the Electronically Retrieved Cohort of HCV Infected Veterans (ERCHIVES) database, we identified all subjects initiated on HCV antibody (anti-HCV) therapy from 2001 to 2014, and all incident cases of cirrhosis and HCC. Statin use was measured using cumulative defined daily dose (cDDD). Multivariable Cox's proportional hazard regression models were used to examine the relationship between statin use and development of cirrhosis and HCC. Among 9,135 eligible subjects, 1,649 developed cirrhosis and 239 developed incident HCC. Statin use was associated with a 44% reduction in development of cirrhosis (adjusted hazard ratio [HR]: 0.6; 95% confidence interval [CI]: 0.53, 0.68). The adjusted HRs (95% CI) of fibrosis progression with statin cDDD 28-89, 89-180, and >180 were 0.74 (0.59, 0.93), 0.71 (0.59, 0.88), and 0.6 (0.53, 0.68), respectively. Mean change in FIB-4 score with atorvastatin (n = 944) and fluvastatin (n = 34) was -0.17 and -0.13, respectively (P = 0.04), after adjustment for baseline FIB-4 score and established predictors of cirrhosis. Statin use was also associated with a 49% reduction in incident HCC (adjusted HR: 0.51; 95% CI: 0.36, 0.72). A similar dose-response relationship was observed.

CONCLUSION

In patients with chronic HCV, statin use was associated with a dose-dependent reduction in incident cirrhosis and HCC. Atorvastatin and fluvastatin were associated with the most significant antifibrotic effects, compared with other statins. (Hepatology 2016;64:47-57).

Statin pretreatment inhibits the lipopolysaccharide-induced epithelial-mesenchymal transition via the downregulation of toll-like receptor 4 and nuclear factor-κB in human biliary epithelial cells

BACKGROUND AND AIM

Epithelial-mesenchymal transition (EMT) of biliary epithelial cells (BECs) plays an important role in biliary fibrosis. This study investigated the effects of simvastatin on the lipopolysaccharide (LPS)-induced EMT and related signal pathways in BECs.

METHODS

Biliary epithelial cells were exposed to LPS (2 µg/mL) or transforming growth factor β1 (TGF-β1) (5 ng/mL) for 5 days. The EMT was assessed by a gain of mesenchymal cell markers (vimentin, N-cadherin, slug, and Twist-1) and a loss of epithelial cell markers (E-cadherin). The effects of simvastatin on the EMT induced by LPS or TGF-β1 were determined by the changes in the levels of EMT markers and TLR4 and in the c-Jun N-terminal kinase (JNK), p38, and nuclear factor-κB (NF-κB) signaling pathways.

RESULTS

Compared with the BECs treated with LPS alone, co-treatment with simvastatin and LPS induced an increase in the expression of E-cadherin and decreases in the expression levels of mesenchymal cell markers. The LPS-induced TLR4 expression level was slightly decreased by co-treatment with simvastatin. LPS-induced BEC growth was markedly inhibited by co-treatment with simvastatin. Furthermore, pretreatment with simvastatin inhibited the LPS-induced EMT in BECs by downregulating NF-κB and JNK phosphorylation. The suppressive effects of simvastatin pretreatment on the induction of the EMT by TGF-β1 were also demonstrated in H69 cells.

CONCLUSIONS

Our results demonstrate that LPS or TGF-β1 promote the EMT in BECs that that pretreatment with simvastatin inhibited the induced EMT by downregulating toll-like receptor 4 and NF-κB phosphorylation. This finding suggests that simvastatin can be considered a new agent for preventing biliary fibrosis associated with the EMT of BECs.

Statin use and the risk of cirrhosis development in patients with hepatitis C virus infection

BACKGROUND & AIMS

Several animal studies have shown that statins can inhibit the progression of cirrhosis; however, few clinical studies have been conducted. Previous studies have indicated that statins can prevent the progression of hepatic fibrosis in patients with hepatitis C virus (HCV) infection and advanced hepatic fibrosis, however data is lacking on patients who have yet to progress to cirrhosis. This study investigated the association between the use of statin and the risk of cirrhosis development in patients with HCV infection.

METHODS

We conducted a population-based cohort study by using the Taiwan National Health Insurance Research Database. A total of 226,856 patients with HCV infection were included as the study cohort. Each patient was followed from 1997 to 2010 to identify incident cases of cirrhosis. A Cox proportional hazard regression was performed to evaluate the association between statin use and cirrhosis risk.

RESULTS

A total of 34,273 cases of cirrhosis were identified in the cohort with HCV infection during the follow-up period of 2,874,031.7 person-years. The incidence rate was 445.5 cases of cirrhosis per 100,000 person-years (95% confidence interval (CI), 423.3 to 465.7) for statin users (defined as those who used more than 28 cumulative defined daily doses (cDDD)), and 1311.2 cirrhosis cases per 100,000 person-years (95% CI, 1297.1 to 1325.6) for non-users. A dose-response relationship between statin use and cirrhosis risk was observed. The adjusted hazard ratios were 0.33 (95% CI, 0.31 to 0.36), 0.24 (95% CI, 0.22 to 0.25), and 0.13 (95% CI, 0.12 to 0.15) for statin use of 28 to 83, 84 to 365, and more than 365 cDDD, respectively, relative to no statin use (<28 cDDD).

CONCLUSION

Among the patients with HCV infection, statin use was associated with a reduced risk of cirrhosis development in a dose-dependent manner. Further clinical research is required.

Antifibrotic effect of AT-1 blocker and statin in rats with hepatic fibrosis

Hepatic fibrosis is an outcome of chronic liver injury. Angiotensin II (ANG II) may play a role in the pathogenesis of hepatic fibrosis. Certain drugs such as ACE inhibitors, ANG II antagonists, and even statins could interfere with the renin angiotensin system and modulate its deleterious effects. This study was carried out to investigate the possible role of losartan and atorvastatin in liver fibrosis. Liver fibrosis was induced in rats by i.p. injection of 50% CCl₄ twice per week for 8 weeks. The rats intoxicated with CCl₄ were divided into four groups: fibrosis control; losartan group; atorvastatin group; and co-treated group. A fifth group of normal healthy rats served as a control group. The results showed that losartan and atorvastatin, either alone or in combination, significantly decreased ALT, AST, hyaluronic acid and hydroxyproline levels in their groups compared to those of the fibrosis control group. A significant decrease in TGF-β was found in the losartan and co-treated groups but not in the atorvastatin group. These biochemical data were supported by liver histopathology and α-SMA. The results indicate that the combined treatment with both losartan and atorvastatin produced a greater effect than either drug alone and proved a beneficial role in inhibiting or reversing liver fibrosis.

Lipid dysregulation in hepatitis C virus, and impact of statin therapy upon clinical outcomes

The hepatitis C virus (HCV) is one of the most common causes of chronic liver disease and the leading indication for liver transplantation worldwide. Every aspect of the HCV life cycle is closely tied to human lipid metabolism. The virus circulates as a lipid-rich particle, utilizing lipoprotein cell receptors to gain entry into the hepatocyte. It has also been shown to upregulate lipid biosynthesis and impair lipid degradation, resulting in significant intracellular lipid accumulation and circulating hypocholesterolemia. Patients with chronic hepatitis C (CHC) are at increased risk of hepatic steatosis, fibrosis, and cardiovascular disease including accelerated atherosclerosis. HMG CoA Reductase inhibitors, or statins, have been shown to play an important role in the modulation of hepatic steatosis and fibrosis, and recent attention has focused upon their potential therapeutic role in CHC. This article reviews the hepatitis C viral life cycle as it impacts host lipoproteins and lipid metabolism. It then describes the pathogenesis of HCV-related hepatic steatosis, hypocholesterolemia and atherosclerosis, and finally describes the promising anti-viral and anti-fibrotic effects of statins, for the treatment of CHC.

Ipragliflozin, an SGLT2 inhibitor, exhibits a prophylactic effect on hepatic steatosis and fibrosis induced by choline-deficient l-amino acid-defined diet in rats

Ipragliflozin is a selective sodium glucose cotransporter 2 (SGLT2) inhibitor that increases urinary glucose excretion by inhibiting renal glucose reabsorption and thereby causes a subsequent antihyperglycemic effect. As nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), is closely linked to metabolic diseases such as obesity and diabetes, we investigated the effect of ipragliflozin on NAFLD in rats fed a choline-deficient l-amino acid-defined (CDAA) diet. Five weeks after starting the CDAA diet, rats exhibited hepatic triglyceride (TG) accumulation, fibrosis, and mild inflammation. Repeated oral administration of ipragliflozin (3mg/g, once daily for 5 weeks) prevented both hepatic TG accumulation (188 vs.290 mg/g tissue vehicle-treated group; P<0.001) and large lipid droplet formation. Further, ipragliflozin exerted a prophylactic effect on liver fibrosis, as indicated by a marked decrease in hydroxyproline content and fibrosis score. Pioglitazone, which is known to be effective on hepatic fibrosis in CDAA diet-fed rats as well as NASH patients with type 2 diabetes mellitus (T2DM), also exerted a mild prophylactic effect on fibrosis, but not on hepatic TG accumulation or inflammation. In conclusion, ipragliflozin prevented hepatic TG accumulation and fibrosis in CDAA-diet rats. These findings suggest the therapeutic potential of ipragliflozin for patients with NAFLD.

Fluvastatin attenuates hepatic steatosis-induced fibrogenesis in rats through inhibiting paracrine effect of hepatocyte on hepatic stellate cells

Background

Non-alcoholic steatohepatitis (NASH) is associated with hepatic fibrogenesis. Despite well-known cholesterol-lowering action of statins, their mechanisms against NASH-mediated fibrogenesis remain unclear. This study aimed at investigating the in vitro and in vivo anti-fibrotic properties of fluvastatin (Flu).

Methods

Palmitate (PA)-induced changes in intracellular hydrogen peroxide levels in primary rat hepatocytes (PRHs) and human hepatoma cell line (HepG2) were quantified by dichlorofluorescein diacetate (DCF-DA) dye assay, whereas changes in expressions of NADPH oxidase gp91^phox subunit, α-smooth muscle actin (α-SMA), and NFκB p65 nuclear translocation were quantified with Western blotting. Quantitative real-time polymerase chain reaction (q-PCR) was used to investigate mRNA expressions of pro-inflammatory genes (ICAM-1, IL-6, TNF-α). Conditioned medium (CM) from PA-treated PRHs was applied to cultured rat hepatic stellate cell line, HSC-T6, with or without Flu-pretreatment for 2 h. Pro-fibrogenic gene expressions (COL1, TIMP-1, TGF-β1, α-SMA) and protein expression of α-SMA were analyzed. In vivo study using choline-deficient L-amino acid defined (CDAA) diet-induced rat NASH model was performed by randomly assigning Wistar rats (n = 28) to normal controls (n = 4), CDAA diet with vehicles, and CDAA diet with Flu (5 mg/kg or 10 mg/kg) (n = 8 each) through gavage for 4 or 8 weeks. Livers were harvested for histological, Western blot (α-SMA), and q-PCR analyses for expressions of pro-inflammatory (IL-6, iNOS, ICAM-1) and pro-fibrogenic (Col1, α-SMA, TIMP-1) genes.

Results

In vitro, Flu (1–20 μM) inhibited PA-induced free-radical production, gp91^phox expression, and NFκB p65 translocation in HepG2 and PRHs, while CM-induced α-SMA protein expression and pro-fibrogenic gene expressions in HSC-T6 were suppressed in Flu-pretreated cells compared to those without pretreatment. Moreover, α-SMA protein expression was significantly decreased in HSC-T6 cultured with CM from PA-Flu-treated PRHs compared to those cultured with CM from PA-treated PRHs. Flu also reduced steatosis and fibrosis scores, α-SMA protein expression, mRNA expression of pro-inflammatory and pro-fibrogenic genes in livers of CDAA rats.

Conclusions

We demonstrated PA-induced HSC activation through paracrine effect of hepatocyte in vitro that was significantly suppressed by pre-treating HSC with Flu. In vivo, Flu alleviated steatosis-induced HSC activation and hepatic fibrogenesis through mitigating inflammation and oxidative stress, suggesting possible therapeutic role of Flu against NASH.

Statin use is associated with a reduced risk of fibrosis progression in chronic hepatitis C

BACKGROUND & AIMS

Therapies that slow fibrosis progression in chronic liver disease are needed. Animal models have demonstrated that statins prevent the progression of hepatic fibrosis, but human data is lacking so far. We evaluated the association between statins and fibrosis progression in the HALT-C trial cohort.

METHODS

Subjects with chronic hepatitis C (CHC) and advanced hepatic fibrosis underwent serial liver biopsies over 3.5 years. The primary outcome was a ⩾ 2-point increase in the Ishak fibrosis score on at least one of two serial biopsies. We used complementary log-log regression analysis to assess the association between statins and fibrosis progression among subjects without baseline cirrhosis.

RESULTS

Fibrosis progression occurred in 3/29 (10%) statin users and 145/514 (29%) non-users. The unadjusted hazard ratio (HR) for fibrosis progression among statin users compared to non-users was 0.32 (95% CI 0.10-0.99). This association remained significant after adjusting for established predictors of histological outcome, including body mass index, platelets and hepatic steatosis (adjusted HR 0.31; 95% CI 0.10-0.97). The mean change in Ishak fibrosis score over the 3.5 year study period was -0.34 (SE 0.18) for statin users compared to +0.42 (SE 0.07) for non-users (p = 0.006, after adjustment for baseline fibrosis score).

CONCLUSIONS

Statin use is associated with a reduced risk of fibrosis progression in advanced CHC. Our findings suggest a potential role for statins in preventing liver disease progression.

Neonatal monosodium glutamate treatment causes obesity, diabetes, and macrovesicular steatohepatitis with liver nodules in DIAR mice

BACKGROUND AND AIM

Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome (MS). Monosodium glutamate (MSG)-treated ICR mice is a useful model of MS and NASH, but it shows the different patterns of steatosis from human NASH. Because inbred aged DIAR (ddY, Institute for Animal Reproduction) mice spontaneously show the similar pattern of steatosis as NASH, we analyzed their liver pathology after administering MSG.

METHODS

MSG-treated DIAR mice (DIAR-MSG) and untreated DIAR mice (DIAR-controls) were sacrificed and assessed histopathologically at 29, 32, 40, 48, and 54 weeks of age. The NASH activity score, body mass index, blood glucose level, and oral glucose tolerance test were also assessed.

RESULTS

The body mass index and blood glucose levels of DIAR-MSG were significantly higher than controls. The oral glucose tolerance test revealed a type 2 diabetes pattern in DIAR-MSG. The livers of DIAR-MSG mice showed macrovesicular steatosis, lobular inflammation with neutrophils, and ballooning degeneration after 29 weeks. At 54 weeks, mild fibrosis was observed in 5/6 DIAR-MSG and 2/5 DIAR-control mice. In imaging mass spectrometry analysis, cholesterol as well as triglyceride accumulated in the liver of DIAR-MSG mice. Atypical liver nodules were also observed after 32 weeks in DIAR-MSG, some with cellular and structural atypia mimicking human hepatocellular carcinoma. The NASH activity score of DIAR-MSG after 29 weeks was higher than that of control mice, suggesting the development of NASH.

CONCLUSIONS

DIAR-MSG had NASH-like liver pathology and liver nodules typically associated with MS symptoms. DIAR-MSG provides a valuable animal model to analyze NASH pathogenesis and carcinogenesis.

Inhibitory effects of pitavastatin on fibrogenic mediator production by human lung fibroblasts

AIMS

Idiopathic pulmonary fibrosis continues to be a devastating clinical disorder for which there are few therapeutic options, and the pathogenesis of this disease remains largely unknown. Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in cholesterol biosynthesis, and they have been reported to exert pleiotropic effects on the cellular signaling involved in tissue inflammation and in organ fibrosis/remodeling. We examined the preventive effects of statins on fibrogenic mediator expression and production in normal human lung fibroblasts (NHLF).

MAIN METHODS

NHLF were pretreated with 100nM pitavastatin or medium alone (control), and were then stimulated with transforming growth factor-β1 (TGF-β1). mRNA expression and protein secretion of several mediators from cells were analyzed by real-time polymerase chain reaction, enzyme-linked immunosorbent assay or multiplex assay.

KEY FINDINGS

TGF-β1-induced expression or production of mediators, such as collagen-1, vascular endothelial growth factor and chemokine C-X-C motif ligand 8, in NHLF pretreated with pitavastatin was significantly suppressed with inhibition of Smad-3 phosphorylation, as compared to untreated controls. In addition, the inhibitory effects of pitavastatin were negated by addition of mevalonate.

SIGNIFICANCE

Pitavastatin appeared to inhibit TGF-β1-induced fibrogenic mediator production from lung fibroblasts via the mevalonic cascade. Although further evaluation of the signaling pathways for these phenomena is necessary, our results suggest the potential benefits of pitavastatin.

Simvastatin ameliorates liver fibrosis via mediating nitric oxide synthase in rats with non-alcoholic steatohepatitis-related liver fibrosis

Background

Simvastatin exerts pleiotropic effects on cardiovascular system. However, its effect on non-alcoholic fatty liver disease, especially the liver fibrosis, remains obscure. We aimed to clarify the relationship between simvastatin and liver fibrosis both in vivo and in vitro.

Methods

A High-fat diet was given to establish rat models with non-alcoholic steatohepatitis (NASH)-related liver fibrosis and simvastatin (4mg·kg^-1·d^-1) was administrated intragastrically until hepatic histological findings confirmed the appearance of fibrosis. Human hepatic stellate cell (HSC) line lx-2 cells were cultured in an adipogenic differentiating mixture (ADM) and then were treated with transforming growth factorβ1 (TGF-β1), served as a positive control, simvastatin, TGF-β1 plus simvastatin, N_ω-nitro-L-arginine methyl ester hydrochloride (L-NAME, a inhibitor of nitric oxide synthase), and L-NAME plus simvastatin, respectively. The expressions of endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and Collagen І as well as cellular α-smooth muscle actin (α-SMA) were measured by real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot in liver tissue and HSC.

Results

With the progress of NASH-related fibrosis, hepatic mRNA and protein expressions of iNOS, α-SMA, and Collagen І were increased while those of eNOS were decreased. Compared with model rats in 24^th week group, rats in simvastatin group had less expressions of iNOS, α-SMA, and Collagen І and more expressions of eNOS. In vitro, LX-2 cells acquired quiescent phenotype when cultured in ADM, and TGF-β1 could activate the quiescent HSC. Simvastatin inhibited LX-2 cells activation due to TGF-β1 or L-NAME by increasing the expression of eNOS and decreasing the expression of iNOS.

Conclusions

Simvastatin improves the prognosis of NASH-related fibrosis by increasing the expression of eNOS, decreasing the expression of iNOS, and inhibiting the activation of HSC.

Pitavastatin ameliorated the progression of steatohepatitis in ovariectomized mice fed a high fat and high cholesterol diet

AIM

Many studies indicate an accelerated progression of non-alcoholic steatohepatitis (NASH) in postmenopausal women. Very recently, we reported that estrogen deficiency enhanced the progression of steatohepatitis in mice fed a high fat and high cholesterol (HFHC) diet. Hypercholesterolemia is often observed in postmenopausal women, and recent studies indicate it to be an important risk factor for the progression of NASH. Statins can slow NASH progression in the estrogen-deficient state but the precise mechanisms of their effects are still unclear.

METHODS

We investigated the effects of pitavastatin on steatohepatitis progression using ovariectomized (OVX) mice fed a HFHC diet or HFHC + pitava diet (containing 5 p.p.m. pitavastatin) for 6 weeks.

RESULTS

Serum alanine aminotransferase and cholesterol levels significantly decreased in mice fed the HFHC + pitava diet compared with mice fed the HFHC diet. Real-time reverse transcription polymerase chain reaction representing hepatic inflammatory gene expressions significantly decreased in mice fed the HFHC + pitava diet compared with the HFHC-fed mice. Pitavastatin treatment also decreased both hepatic macrophage infiltration and hepatocyte chemokine (C-C motif) ligand 2 expression and improved the liver fibrosis condition when compared with the mice fed the HFHC diet. In addition, the enhanced spleen monocyte chemokine (C-C motif) receptor 2 expression in ovariectomized mice fed the HFHC diet was also decreased by pitavastatin administration.

CONCLUSION

Our study demonstrated that the exacerbated steatohepatitis progression in OVX mice fed a HFHC diet could be attenuated by pitavastatin treatment at least through inhibition of hepatic macrophage infiltration. We concluded that statins should be useful for treating NASH in postmenopausal women.

Atorvastatin and rosuvastatin do not prevent thioacetamide induced liver cirrhosis in rats

AIM: To examine whether the administration of atorvastatin and rosuvastatin would prevent experimentally-induced hepatic cirrhosis in rats.

METHODS: Liver cirrhosis was induced by injections of thioacetamide (TAA). Rats were treated concurrently with TAA alone or TAA and either atorvastatin (1,10 and 20 mg/kg) or rosuvastatin (1, 2.5, 5, 10 and 20 mg/kg) given daily by nasogastric gavage.

RESULTS: Liver fibrosis and hepatic hydroxyproline content, in the TAA-treated group was significantly higher than those of the controls [11.5 ± 3.2 vs 2.6 ± 0.6 mg/g protein (P = 0.02)]. There were no differences in serum aminotransferase levels in the TAA controls compared to all the groups treated concomitantly by statins. Both statins used in our study did not prevent liver fibrosis or reduce portal hypertension, and had no effect on hepatic oxidative stress. Accordingly, the hepatic level of malondialdehyde was not lower in those groups treated by TAA + statins compared to TAA only. In vitro studies, using the BrdU method have shown that atorvastatin had no effect of hepatic stellate cells proliferation. Nevertheless, statin treatment was not associated with worsening of liver damage, portal hypertension or survival rate.

CONCLUSION: Atorvastatin or rosuvastatin did not inhibit TAA-induced liver cirrhosis or oxidative stress in rats. Whether statins may have therapeutic applications in hepatic fibrosis due to other etiologies deserve further investigation.

Ex vivo-expanded bone marrow stem cells home to the liver and ameliorate functional recovery in a mouse model of acute hepatic injury

BACKGROUND

Stem cell transplantation provides a theoretical approach for liver regeneration medicine; it may promote liver regeneration and self-repair. However, the transplantation of bone marrow-mesenchymal stem cells expanded ex vivo as a therapy for liver disease has rarely been investigated. This study aimed to explore whether bone marrow stem cells expanded ex vivo home to the liver and foster hepatic recovery after CCl4 injury.

METHODS

Bone marrow cells from BALB/c mice were expanded ex vivo by multiple-passage cultivation, characterized by cytoflow immunofluorescence, and pre-labeled with PKH26 before intravenous infusion into animals treated with CCl4. The integration of bone marrow cells into the liver was examined microscopically, and plasma hepatic enzymes were determined biochemically.

RESULTS

Cultured bone marrow cells exhibited antigenic profiles comparable to those of primary medullary stem cells. Double immunofluorescence showed colocalization of these cells with proliferative activity and albumin expression in the liver of CCl4-treated mice. Densitometry showed increased in situ cell proliferation (50+/-14 vs 20+/-3 cells/high-power field, P<0.05) and albumin expression (149+/-25 vs 20+/-5 cells/high-power field, P<0.05) in the liver, as well as reduced serum aminotransferase levels (P<0.05) and better survival rates (P<0.05) in animals receiving cultured bone marrow cells relative to controls.

CONCLUSIONS

Ex vivo-expanded bone marrow cells are capable of relocating to and proliferating in the chemically-injured liver. Transplantation of these pluripotent stem cells appears to improve serum indices of liver function and survival rate in mice after CCl4-induced hepatic damage.

Cholesterol-lowering therapy for the treatment of nonalcoholic fatty liver disease: an update

PURPOSE OF REVIEW

To review recent human trials assessing cholesterol-lowering agents in nonalcoholic fatty liver disease (NAFLD).

RECENT FINDINGS

Four randomized controlled trials (RCTs) assessed statins in NAFLD. In the only RCT with post-treatment biopsy, simvastatin did not change liver histology. In the remaining RCTs, atorvastatin was well tolerated, significantly improved radiological/biochemical markers of steatosis and plasma lipids, with neutral effects on glucose metabolism; in the Greek Atorvastatin and Coronary Heart Disease Evaluation (GREACE) study, atorvastatin reduced incident cardiovascular disease compared with both untreated NAFLD patients and with statin-treated patients without NAFLD. Ezetimibe was evaluated in two uncontrolled trials and two RCTs, consistently improving liver histology and plasma lipids, whereas glucose metabolism was generally unaffected; however, HbA1c increased with ezetimibe in one RCT.

SUMMARY

From the analysis of available trials, it emerges that cholesterol-lowering agents may considerably benefit NAFLD patients. Statins are well tolerated, and atorvastatin improved surrogate markers of liver disease, whereas their effect on liver histology is unknown. Furthermore, the GREACE study was the first trial to show clinical benefit from the use of a pharmacological agent in NAFLD. Ezetimibe improved liver histology. The benefit of combination therapy, as well as the safety on glucose metabolism, need further evaluation.