Telmisartan prevents hepatic fibrosis and enzyme-altered lesions in liver cirrhosis rat induced by a choline-deficient l-amino acid-defined diet

EFFECTS OF DIOSMIN ADMINISTRATION ON CISPLATIN-INDUCED PREMATURE OVARIAN FAILURE IN A RAT MODEL

m We aimed to examine the potential beneficial effects of diosmin administration on cisplatin - induced premature ovarian failure (POF) in a rat model Material and Methods Twenty-eight rats were divided into four groups. Group A rats (n:7) were determined as the sham group. The remaining rats received an intraperitoneal injection of 1.5 mg/kg/day cisplatin for 10 days to create a POF model. Then, they were randomly divided into 3 subgroups. Group B was determined as POF group. Group C rats were given 100mg/kg/day diosmin for 10 days simultaneously while creating POF model. Group D rats were given 100mg/kg/day diosmin for 10 days after POF model was created. Twentieth day blood samples were taken and left ovaries were resected for examination. Results CIS-induced rats showed reduced levels of SOD, AMH and E2 compared to sham group rats (p0.05) between the sham group, group C and D. No significant (p>0.05) difference in FSH value was observed between group C, D and sham groups. There was no significant (p>0.05) difference in the number of secondary and antral follicles between group C and D compared to the sham group. Primordial follicle count was significantly higher in group C than group B (p

Telmisartan relieves liver fibrosis and portal hypertension by improving vascular remodeling and sinusoidal dysfunction

BACKGROUNDS

Telmisartan(TEL) has demonstrated anti-fibrotic and blood pressure lowering effect in various diseases. In this study, we aimed to explore the beneficial effects of TEL on portal hypertension(PHT).

METHODS

Two models of cirrhosis-induced PHT were involved including carbon tetrachloride injection(CCl4) and bile duct ligation(BDL). Rats were orally gavaged with TEL for 4 weeks. After that, the portal pressure(PP) was determined, and liver and mesenteric tissue specimens were collected to evaluate inflammatory response, liver fibrosis, vascular remodeling, angiogenesis, etc. RESULTS: In CCl4 PHT models, TEL decreased PP significantly from 12.79 ± 2.92 to 6.91 ± 1.19 mmHg(p < 0.05). In inflammatory response, hepatic expressions of interleukin(IL)-6, lipopolysaccharide(LPS), and tumor necrosis factor-α(TNF-α) were significantly decreased after TEL treatment. Moreover, in the liver fibrotic area, the expressions of α-smooth muscle actin(α-SMA), collagen1a1(Col1a1), desmin, transforming growth factor-β(TGF-β), and hydroxyproline, and serum hyaluronic acid were significantly decreased after TEL treatment. Additionally, the expressions of von Willebrand factor(vWF), vascular endothelial growth factor(VEGF) and platelet-derived growth factor-β(PDGF-β), matrix metallopeptidase(MMP)-2, and MMP-9 were ameliorated in liver sinusoid, while the expressions of MMP-2 and vWF were reduced in mesenteric arteries after TEL treatment. Meanwhile, TEL treatment up-regulated the hepatic expressions of an anti-fibrotic factor Krüppel-like factor-4(KLF-4) and its downstream endothelial nitric oxide synthase(eNOS) in rats with PHT. The performance of TEL in BDL model was similar but slightly weaker.

CONCLUSIONS

TEL ameliorated the cirrhosis-induced PHT by reducing liver fibrosis, inflammation responses, angiogenesis, and vascular remodeling. Collectively, KLF-4 and eNOS were the possible molecular targets for the management of cirrhosis-associated PHT.

ASK1 Enhances Angiotensin II-Induced Liver Fibrosis In Vitro by Mediating Endoplasmic Reticulum Stress-Dependent Exosomes

Background

Apoptosis signal-regulating kinase 1 (ASK1) has been reported to induce fibrotic signaling in the setting of oxidative stress. However, the role of ASK1 and its mechanism of action in angiotensin II- (Ang II-) induced liver fibrosis remain largely unknown.

Methods

Human hepatic LX-2 stellate cells were treated with Ang II alone or cotreated with Ang II plus an ASK1 inhibitor (GS-4997) or siRNA-targeting ASK1. Immunofluorescent staining, real-time PCR, and western blotting were used to determine the expressionof α-SMA, Col I, and Col III expression. Cell viability was assessed by the CCK-8 assay. The concentrations of IL-1β, IL-18, and TNF-α in conditioned medium were determined by ELISA. The levels of intracellular ROS in LX-2 cells were analyzed using a ROS assay kit. Exosome size was determined by electron microscopy.

Results

Ang II markedly increased the expression of extracellular matrix (ECM) proteins (α-SMA, Col I, and Col III) and proinflammatory cytokines (IL-1β, IL-18, and TNF-α). Ang II also increased the expression of endoplasmic reticulum stress (ERS) markers (GRP78, p-PERK, and CHOP) and p-ASK1. Results also showed that pretreatment with GS-4997 or siRNA could abolish all the abovementioned effects on LX-2 cells. Furthermore, we found that exosome release caused by ASK1-mediated ERS was involved in the activation of LX-2 cells by Ang II. The activation of LX-2 cells could be blocked by treating the exosomes with annexin.

Conclusions

In summary, we found that ASK1 mediates Ang II-activated ERS in HSCs and the subsequent activation of HSCs, suggesting a promising strategy for treating liver fibrosis.

Telmisartan Therapy Does Not Improve Lymph Node or Adipose Tissue Fibrosis More Than Continued Antiretroviral Therapy Alone

Background

Fibrosis in lymph nodes may limit CD4+ T-cell recovery, and lymph node and adipose tissue fibrosis may contribute to inflammation and comorbidities despite antiretroviral therapy (ART). We hypothesized that the angiotensin receptor blocker and peroxisome proliferator-activated receptor γ agonist telmisartan would decrease lymph node or adipose tissue fibrosis in treated human immunodeficiency virus type 1 (HIV) infection.

Methods

In this 48-week, randomized, controlled trial, adults continued HIV-suppressive ART and received telmisartan or no drug. Collagen I, fibronectin, and phosphorylated SMAD3 (pSMAD3) deposition in lymph nodes, as well as collagen I, collagen VI, and fibronectin deposition in adipose tissue, were quantified by immunohistochemical analysis at weeks 0 and 48. Two-sided rank sum and signed rank tests compared changes over 48 weeks.

Results

Forty-four participants enrolled; 35 had paired adipose tissue specimens, and 29 had paired lymph node specimens. The median change overall in the percentage of the area throughout which collagen I was deposited was -2.6 percentage points (P = 0.08) in lymph node specimens and -1.3 percentage points (P = .001) in adipose tissue specimens, with no between-arm differences. In lymph node specimens, pSMAD3 deposition changed by -0.5 percentage points overall (P = .04), with no between-arm differences. Telmisartan attenuated increases in fibronectin deposition (P = .06). In adipose tissue, changes in collagen VI deposition (-1.0 percentage point; P = .001) and fibronectin deposition (-2.4 percentage points; P < .001) were observed, with no between-arm differences.

Conclusions

In adults with treated HIV infection, lymph node and adipose tissue fibrosis decreased with continued ART alone, with no additional fibrosis reduction with telmisartan therapy.

Pilot study of the antifibrotic effects of the multikinase inhibitor pacritinib in a mouse model of liver fibrosis

Background

Fibrotic diseases result from an exuberant response to chronic inflammation. Myelofibrosis is the end result of inflammation in bone, caused by an inflammatory process triggered by production of abnormal myeloid cells driven by mutations affecting the JAK-STAT pathway. Inflammatory cytokine overproduction leads to increased mesenchymal cell proliferation, culminating in fibrosis. Although JAK2 inhibitors, such as the JAK1/2 inhibitor ruxolitinib and the JAK2/FLT3/CSF1R/IRAK1 inhibitor pacritinib suppress abnormal clone expansion in myelofibrosis, ruxolitinib does not appear to prevent or reverse bone-marrow fibrosis in most patients. In two Phase III clinical trials, pacritinib, however, demonstrated improvements in platelet counts and hemoglobin and reductions in transfusion burden in some patients with baseline cytopenias, suggesting it may improve bone-marrow function. Unlike ruxolitinib, pacritinib suppresses signaling through IRAK1, a key control point for inflammatory and fibrotic signaling.

Purpose

To investigate potential antifibrotic effects of pacritinib in an animal model of liver fibrosis relevant to the observed course of human disease.

Methods

Pacritinib, negative control (vehicle), and positive control (the angiotensin 2-receptor antagonist and PPARγ partial agonist telmisartan) were assessed in the murine Stelic animal model, which mimics the clinically observed progression from hepatic steatosis to nonalcoholic steatohepatitis, liver fibrosis, and hepatocellular carcinoma. Histopathological analysis used hematoxylin and eosin staining. Body and liver weight changes, nonalcoholic fatty-liver disease activity scores, and plasma cytokeratin 18 fragment levels (a biomarker of hepatic necrosis) were measured.

Results

Pacritinib-treated mice had significantly (P<0.01) reduced fibrotic areas in liver compared to vehicle control and significantly (P<0.05) lower levels of CK18. The antifibrotic effect of pacritinib was comparable to that of telmisartan, but without significant effects on fat accumulation.

Conclusion

These results, the first to demonstrate hepatic antifibrotic effects for pacritinib in an animal model of liver disease, provide preliminary support for potential clinical applications of pacritinib in fibrotic diseases other than myelofibrosis.

Effects of telmisartan on improving leptin resistance and inhibiting hepatic fibrosis in rats with non-alcoholic fatty liver disease

The present study aimed to investigate the impacts of telmisartan (TEL) on hepatic fibrosis, serum leptin, leptin protein in liver tissue and its mRNA expression level in rats with non-alcoholic fatty liver disease (NAFLD). Male Sprague Dawley rats were randomly divided into the control (N), model (M), polyene phosphatidylcholine (P) and TEL (T) groups. Group M and the intervention groups were given a high-fat diet for 12 weeks to induce NAFLD, followed by 4 weeks of intragastric administration of normal saline (1.0 ml/kg/day), polyene phosphatidylcholine (PPC; 123.1 mg/kg/day) and TEL (8 mg/kg/day). The liver tissue was then assessed for the NAFLD activity score and fibrosis score (FS), and serum biochemistry and leptin levels were determined. Additionally, leptin protein expression levels were examined by western blotting and the expression of leptin mRNA was investigated by reverse transcription-polymerase chain reaction. TEL significantly improved FS in rats (P<0.01) and was more effective than PPC. TEL significantly reduced the expression of serum leptin, as well as the expression levels of leptin protein and its mRNA in liver tissue (P<0.01); however, the effects of PPC were not significant (P>0.05). TEL reduced serum leptin, leptin protein and its mRNA in the liver tissue of NAFLD rats, and improved the pathological indicators of liver fibrosis.

Molecular hepatoprotective effects of lipoic acid against carbon tetrachloride-induced liver fibrosis in rats: Hepatoprotection at molecular level

BACKGROUND

Liver fibrosis is a noteworthy well-being issue that can prompt the progression of liver cirrhosis and hepatocellular carcinoma. Prominently, many antioxidants have been shown to have defensive impacts against liver fibrosis.

AIM

Subsequently, in the present study, the viability of alpha-lipoic acid (α-LA) in ensuring against carbon tetrachloride (CCl₄)-actuated liver fibrosis and the mechanism(s) involved in this defensive impact were considered in rats.

RESULTS

The present results uncovered that in the CCl₄-treated group, the expression of antioxidant enzymes and matrix metalloproteinase-13 (MMP-13) messenger RNA (mRNA) was downregulated ( p < 0.05), and the levels of lipid peroxide and nitric oxide were increased ( p < 0.05) in the treated rat livers along with increased collagen deposition compared to that of the control group. Also, the gene expression levels of the proinflammatory factors interleukin-6 and tumor necrosis factor-alpha, nuclear factor-kappa B (NF-κB) p65, transforming growth factor-alpha, and inducible nitric oxide synthase (iNOS) were upregulated significantly ( p < 0.05) in the CCl₄ group. These negative impacts were all restrained by α-LA.

CONCLUSIONS

These outcomes show that α-LA might be compelling at forestalling collagen deposition and hepatic oxidative stress as well as downregulating the expression of hepatic proinflammatory cytokines, iNOS, and NF-κB and upregulating MMP-13 expression.

Anti-oxidative effects of curcumin on immobilization-induced oxidative stress in rat brain, liver and kidney

Restraint stress has been indicated to induce oxidative damage in tissues. Several investigations have reported that curcumin (CUR) may have a protective effect against oxidative stress. The present study was designed to investigate the protective effects of CUR on restraint stress induced oxidative stress damage in the brain, liver and kidneys. For chronic restraint stress, rats were kept in the restrainers for 1h every day, for 21 consecutive days. The animals received systemic administrations of CUR daily for 21days. In order to evaluate the changes of the oxidative stress parameters following restraint stress, the levels of malondialdehyde (MDA), reduced glutathione (GSH), as well as antioxidant enzyme activities superoxide dismutase (SOD) glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT) were measured in the brain, liver and kidney of rats after the end of restraint stress. The restraint stress significantly increased MDA level, but decreased the level of GSH and activists of SOD, GPx, GR, and CAT the brain, liver and kidney of rats in comparison to the normal rats (P<0.001). Intraperitoneal administration of CUR significantly attenuated oxidative stress and lipid peroxidation, prevented apoptosis, and increased antioxidant defense mechanism activity in the tissues versus the control group (P<0.05). This study shows that CUR can prevent restraint stress-induced oxidative damage in the brain, liver and kidney of rats and propose that CUR may be useful agents against oxidative stress in the tissues.

The Role of Nuclear Receptors in the Pathophysiology, Natural Course, and Drug Treatment of NAFLD in Humans

Nonalcoholic fatty liver disease (NAFLD) describes steatosis, nonalcoholic steatohepatitis with or without fibrosis, and hepatocellular carcinoma, namely the entire alcohol-like spectrum of liver disease though observed in the nonalcoholic, dysmetabolic, individual free of competing causes of liver disease. NAFLD, which is a major public health issue, exhibits intrahepatic triglyceride storage giving rise to lipotoxicity. Nuclear receptors (NRs) are transcriptional factors which, activated by ligands, are master regulators of metabolism and also have intricate connections with circadian control accounting for cyclical patterns in the metabolic fate of nutrients. Several transcription factors, such as peroxisome proliferator-activated receptors, liver X receptors, farnesoid X receptors, and their molecular cascades, finely regulate energetic fluxes and metabolic pathways. Dysregulation of such pathways is heavily implicated in those metabolic derangements characterizing insulin resistance and metabolic syndrome and in the histogenesis of progressive NAFLD forms. We review the role of selected NRs in NAFLD pathogenesis. Secondly, we analyze the role of NRs in the natural history of human NAFLD. Next, we discuss the results observed in humans following administration of drug agonists or antagonists of the NRs pathogenically involved in NAFLD. Finally, general principles of treatment and lines of research in human NAFLD are briefly examined.

Treatment of nonalcoholic steatohepatitis in adults: present and future

Nonalcoholic steatohepatitis has become one of the most common liver-related health problems. This condition has been linked to an unhealthy diet and weight gain, but it can also be observed in nonobese people. The standard of care is represented by the lifestyle intervention. However, because this approach has several limitations, such as a lack of compliance, the use of many drugs has been proposed. The first-line pharmacological choices are vitamin E and pioglitazone, both showing a positive effect on transaminases, fat accumulation, and inflammation. Nevertheless, vitamin E has no proven effect on fibrosis and on long-term morbidity and mortality and pioglitazone has a negative impact on weight. Other drugs have been studied such as metformin, ursodeoxycholic acid, statins, pentoxiphylline, and orlistat with only partially positive results. Among the emerging treatments, telmisartan is particularly interesting as it seems to have an impact on insulin resistance, liver steatosis, inflammation, and fibrosis. However, the pathogenesis of steatohepatitis is highly complex and is determined by different parallel hits; indeed, the association of different drugs that act on various levels has been suggested. In conclusion, lifestyle intervention should be optimised and the associations of different drugs should be tested in large studies with long-term outcomes.

Telmisartan ameliorates fibrocystic liver disease in an orthologous rat model of human autosomal recessive polycystic kidney disease

Human autosomal recessive polycystic kidney disease (ARPKD) produces kidneys which are massively enlarged due to multiple cysts, hypertension, and congenital hepatic fibrosis characterized by dilated bile ducts and portal hypertension. The PCK rat is an orthologous model of human ARPKD with numerous fluid-filled cysts caused by stimulated cellular proliferation in the renal tubules and hepatic bile duct epithelia, with interstitial fibrosis developed in the liver. We previously reported that a peroxisome proliferator activated receptor (PPAR)-γ full agonist ameliorated kidney and liver disease in PCK rats. Telmisartan is an angiotensin receptor blocker (ARB) used widely as an antihypertensive drug and shows partial PPAR-γ agonist activity. It also has nephroprotective activity in diabetes and renal injury and prevents the effects of drug-induced hepatotoxicity and hepatic fibrosis. In the present study, we determined whether telmisartan ameliorates progression of polycystic kidney and fibrocystic liver disease in PCK rats. Five male and 5 female PCK and normal control (+/+) rats were orally administered 3 mg/kg telmisartan or vehicle every day from 4 to 20 weeks of age. Treatment with telmisartan decreased blood pressure in both PCK and +/+ rats. Blood levels of aspartate amino transferase, alanine amino transferase and urea nitrogen were unaffected by telmisartan treatment. There was no effect on kidney disease progression, but liver weight relative to body weight, liver cystic area, hepatic fibrosis index, expression levels of Ki67 and TGF-β, and the number of Ki67- and TGF-β-positive interstitial cells in the liver were significantly decreased in telmisartan-treated PCK rats. Therefore, telmisartan ameliorates congenital hepatic fibrosis in ARPKD, possibly through the inhibition of signaling cascades responsible for cellular proliferation and interstitial fibrosis in PCK rats. The present results support the potential therapeutic use of ARBs for the treatment of fibrocystic liver disease in ARPKD patients.

Linagliptin alleviates hepatic steatosis and inflammation in a mouse model of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is a primary cause of cirrhosis and hepatocellular carcinoma. Dipeptidyl peptidase (DPP)-4 inhibitors are established therapies for type 2 diabetes and although DPP-4 inhibitors can reduce hepatic steatosis, their impact on local inflammation and fibrosis in NASH remains unknown. Using two different experimental treatment regimens (4- and 2-week treatments) in streptozotocin-treated neonatal mice on a high-fat diet, we show that the DPP-4 inhibitor linagliptin (10 and 30 mg/kg) significantly attenuated the NAS score from 4.9 ± 0.6 to 3.7 ± 0.4 and 3.6 ± 0.3, respectively, in the 4-week study. In the 2-week study, linagliptin 10 mg/kg significantly reduced NAS score from 4.1 ± 0.4 to 2.4 ± 0.4. Telmisartan was used as a positive control in both studies and lowered NAS score to 1.9 ± 0.7 and 1.4 ± 0.3, respectively. Due to streptozotocin treatment, elevated glucose levels were unchanged by either drug treatment. Further, linagliptin 10 mg/kg significantly reduced mRNA levels of SOCS-3 (from 1.68 ± 0.2 to 0.83 ± 0.08), IFN-γ (from 4.0 ± 0.5 to 2.3 ± 0.3), and TNF-α (from 5.7 ± 0.5 to 2.13 ± 0.3). The latter observation was confirmed by immunohistochemistry of TNF-α in liver specimens. In addition, using microautoradiography, we showed that the distribution of radiolabeled linagliptin was heterogeneous with the highest density associated with interlobular bile ducts and portal tracts (acini). In conclusion, these studies confirm that linagliptin has high exposure in hepatic tissue and has both anti-inflammatory and anti-steatotic activity in NASH.

Telmisartan plus propranolol improves liver fibrosis and bile duct proliferation in the PSC-like Abcb4-/- mouse model

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease leading to cirrhosis and cholangiocellular carcinoma. Inhibitors of the renin-angiotensin system or the sympathetic nervous system delay liver fibrogenesis in animal models.

AIMS

We investigated the antifibrotic potential of telmisartan, an angiotensin II type 1 receptor antagonist, and the β-adrenoceptor blocker propranolol in the PSC-like Abcb4 knockout mouse model.

METHODS

Sixty-five Abcb4 (-/-) mice were treated with telmisartan for 3 or 5 months (T) and with telmisartan plus propranolol for 3, 5, or 8 months (TP), or for 2 or 5 months starting with a delay of 3 months (TP delayed). Liver hydroxyproline content, inflammation, fibrosis, and bile duct proliferation were assessed; fibrosis-related molecules were analyzed by real-time polymerase chain reaction and Western blotting.

RESULTS

Compared to controls, telmisartan monotherapy had no significant influence on hydroxyproline; however, telmisartan plus propranolol reduced hydroxyproline (TP 3 months, p = 0.008), fibrosis score (TP 3 months and TP 8 months, p = 0.043 and p = 0.008, respectively; TP delayed 8 months, p < 0.0005), bile duct proliferation (TP 8 months and TP delayed 8 months, p = 0.006 and p < 0.0005, respectively), and procollagen α1(I), endothelin-1, TIMP-1 and MMP3 mRNA as well as α-SMA, CK-19, and TIMP-1 protein.

CONCLUSIONS

Telmisartan plus propranolol reduces liver fibrosis and bile duct proliferation in the PSC-like Abcb4 (-/-) mouse model, even when started at late stages of fibrosis, and may thus represent a novel therapeutic option for cholestatic liver diseases such as PSC.

Angiotensin II type 1 receptor antagonist prevents hepatic carcinoma in rats with nonalcoholic steatohepatitis

BACKGROUND

Angiotensin II type 1 receptor blockers (ARBs) have been reported to attenuate hepatic fibrosis in non-alcoholic steatohepatitis (NASH). However, it is uncertain whether ARBs prevent hepatocarcinogenesis in NASH even after hepatic fibrosis has developed.

METHODS

Male Wistar rats were fed with a choline-deficient, L-amino acid-defined (CDAA) diet for 24 weeks, and then fed with the CDAA diet with telmisartan (2 mg/kg/day), a novel ARB, or vehicle for another 24 weeks. The liver histology and the expression of genes and proteins related to angiogenesis were investigated.

RESULTS

The 24-week CDAA diet induced liver cirrhosis. The 48-week CDAA diet exacerbated liver cirrhosis, and developed hepatocellular carcinoma (HCC) in 54.6 % of the rats concurrently with increases of hypoxia-inducible factor-1α (HIF-1α) protein and vascular endothelial growth factor (VEGF) mRNA, which are potent angiogenic factors in the liver. Telmisartan inhibited hepatic fibrosis and preneoplastic lesions and prevented the development of HCC along with inducing decreases in HIF-1α protein and VEGF mRNA.

CONCLUSIONS

These data indicated that telmisartan may prevent hepatocarcinogenesis through the inhibition of hepatic angiogenesis even after liver cirrhosis has been established.

Deferoxamine preconditioning potentiates mesenchymal stem cell homing in vitro and in streptozotocin-diabetic rats

OBJECTIVE

Today, cell therapy is considered a promising alternative in treatment of several diseases such as type 1 diabetes. Loss of transplanted stem cell and more importantly scarcity in the number of cells reaching to target tissue is a major obstacle in cell therapy. There is evidences showing that deferoxamine (DFO), an iron chelator, increases the mobilization and homing of progenitor cells through increasing the stability of hypoxia-inducible factor 1α (HIF-1α) protein. In this study, the effect of DFO on some factors involved in homing of bone marrow-derived mesenchymal stem cell was investigated, and the other objectives of this research were to determine whether DFO is able to increase migration and subsequent homing of mesenchymal stem cell (MSCs) both in vitro and in vivo in streptozotocin-diabetic rats.

RESEARCH DESIGN AND METHODS

MSCs were treated by DFO in minimal essential medium α (αMEM) for 24 h. The expression and localization of HIF-1α were evaluated by western blotting and immunocytochemistry. The expression of C-X-C chemokine receptor type 4 (CXCR-4) and chemokine receptor 2 (CCR2) were assessed by western blotting and RT-PCR. The activity of matrix metalloproteinases (MMP) -2 and -9 were measured by gelatin zymography. Finally, in vitro migration of MSCs toward different concentrations of stromal cell-derived factor and monocyte chemotactic protein-1 were also evaluated. To demonstrate the homing of MSCs in vivo, DFO-treated chloromethyl-benzamidodialkylcarbocyanine-labeled MSCs were injected into the tail vein of rats, and the number of stained MSCs reaching to the pancreas were determined after 24 h.

RESULTS

In DFO-treated MSCs, expression of HIF-1α (p < 0.001), CXCR4 (p < 0.001), CCR2 (p < 0.001), and the activity of MMP-2 (p < 0.01) and MMP-9 (p < 0.05) were significantly increased compared to control groups. Elevation of HIF-1α, upregulation of CXCR4/CCR2 and higher activity of MMP-2/MMP-9 in DFO-treated MSCs were reversed by 2-methoxyestradiol (2-ME; 5 μmol), a HIF-1α inhibitor. The in vitro migrations as well as in vivo homing of DFO-treated MSCs were also significantly higher than control groups (p < 0.05).

CONCLUSIONS

Preconditioning of MSCs by DFO prior to transplantation could increase homing of MSCs through affecting some chemokine receptors as well as proteases involved and eventually improving the efficacy of cell therapy.

Effect of Telmisartan or Losartan for Treatment of Nonalcoholic Fatty Liver Disease: Fatty Liver Protection Trial by Telmisartan or Losartan Study (FANTASY)

AIM

This study compared the effects of telmisartan and losartan on nonalcoholic fatty liver disease (NAFLD) and biochemical markers of insulin resistance in hypertensive NAFLD patients with type 2 diabetes mellitus.

METHODS

This was a randomized, open-label, parallel-group comparison of therapy with telmisartan or losartan. Nineteen hypertensive NAFLD patients with type 2 diabetes were randomly assigned to receive telmisartan at a dose of 40 mg once a day (n = 12) [DOSAGE ERROR CORRECTED] or losartan at a dose of 50 mg once a day (n = 7) for 12 months.

RESULTS

The telmisartan group showed a significant decline in serum free fatty acid (FFA) level (from 0.87 ± 0.26 to 0.59 ± 0.22 mEq/L (mean ± SD), P = 0.005) and a significant increase in L/S ratio (P = 0.049) evaluated by CT scan, while these parameters were not changed in the losartan group.

CONCLUSION

Although there was no significant difference in improvement in liver enzymes with telmisartan and losartan treatment in hypertensive NAFLD patients with type 2 diabetes after 12 months, it is suggested that telmisartan may exert beneficial effects by improving fatty liver.

Telmisartan attenuates hepatic fibrosis in bile duct-ligated rats

AIM

To evaluate the antifibrotic effect of telmisartan, an angiotensin II receptor blocker, in bile duct-ligated rats.

METHODS

Adult Sprague-Dawley rats were allocated to 3 groups: sham-operated rats, model rats underwent common bile duct ligation (BDL), and BDL rats treated with telmisartan (8 mg/kg, po, for 4 weeks). The animals were sacrificed on d 29, and liver histology was examined, the Knodell and Ishak scores were assigned, and the expression of angiotensin-converting enzyme (ACE) and ACE2 was evaluated with immunohistochemical staining. The mRNAs and proteins associated with liver fibrosis were evaluated using RTQ-PCR and Western blot, respectively.

RESULTS

The mean fibrosis score of BDL rats treated with telmisartan was significantly lower than that of the model rats (1.66±0.87 vs 2.13±0.35, P=0.015). However, there was no significant difference in inflammation between the two groups, both of which showed moderate inflammation. Histologically, treatment with telmisartan significantly ameliorated BDL-caused the hepatic fibrosis. Treatment with telmisartan significantly upregulated the mRNA levels of ACE2 and MAS, and decreased the mRNA levels of ACE, angiotensin II type 1 receptor (AT1-R), collagen type III, and transforming growth factor β1 (TGF-β1). Moreover, treatment with telmisartan significantly increased the expression levels of ACE2 and MAS proteins, and inhibited the expression levels of ACE and AT1-R protein.

CONCLUSION

Telmisartan attenuates liver fibrosis in bile duct-ligated rats via increasing ACE2 expression level.

Bone-marrow-derived cells cultured in serum-free medium reduce liver fibrosis and improve liver function in carbon-tetrachloride-treated cirrhotic mice

We have previously developed autologous bone marrow cell infusion (ABMi) therapy for liver cirrhosis patients. One problem associated with ABMi therapy is that general anesthesia is required to obtain 400 ml bone marrow fluid from liver cirrhosis patients. However, many patients with decompensated cirrhosis do not meet the criteria, because of decreased liver function or an increased bleeding tendency. To overcome these issues, our aim is to derive liver repair cells from small amounts of autologous bone marrow aspirates obtained under local anesthesia and to use these cells in liver cirrhosis patients. Here, we conducted, by using a mouse model, basic research aimed at achieving novel liver regeneration therapy. We cultured bone marrow cells aspirated from the femurs of C57 BL/6 Tg14 (act-EGFP) OsbY01 mice (green fluoresent protein [GFP]-transgenic mice). After 14 days of culture with serum-free medium (good manufacturing practice grade), the obtained spindle-shaped GFP-positive cells were injected (1×10(4) cells) via the caudal vein into mice with carbon tetrachloride (CCl4)-induced cirrhosis. Numerous cultured macrophages and some mesenchymal stem cells repopulated the cirrhotic liver. The results showed that serum albumin, liver fibrosis and liver function were significantly improved in the group treated with cultured bone marrow cells (P<0.01). Moreover, matrix metalloproteinase-9 expression was increased in the liver (P<0.01). Thus, infusion of bone-marrow-derived cultured cells improved liver function and liver fibrosis in mice with CCl4-induced cirrhosis.

Salvianolic Acid B Attenuates Rat Hepatic Fibrosis via Downregulating Angiotensin II Signaling

The renin-angiotensin system (RAS) plays an important role in hepatic fibrosis. Salvianolic acid B (Sal B), one of the water-soluble components from Radix Salviae miltiorrhizae, has been used to treat hepatic fibrosis, but it is still not clear whether the effect of Sal B is related to angiotensin II (Ang II) signaling pathway. In the present study, we studied Sal B effect on rat liver fibrosis and Ang-II related signaling mediators in dimethylnitrosamine-(DMN-) induced rat fibrotic model in vivo and Ang-II stimulated hepatic stellate cells (HSCs) in vitro, with perindopril or losartan as control drug, respectively. The results showed that Sal B and perindopril inhibited rat hepatic fibrosis and reduced expression of Ang II receptor type 1 (AT1R) and ERK activation in fibrotic liver. Sal B and losartan also inhibited Ang II-stimulated HSC activation including cell proliferation and expression of type I collagen I (Col-I) and α-smooth muscle actin (α-SMA) production in vitro, reduced the gene expression of transforming growth factor beta (TGF-β), and downregulated AT1R expression and ERK and c-Jun phosphorylation. In conclusion, our results indicate that Sal B may exert an antihepatic fibrosis effect via downregulating Ang II signaling in HSC activation.

Comparative study of three angiotensin II type 1 receptor antagonists in preventing liver fibrosis in diabetic rats: stereology, histopathology, and electron microscopy

The presence of liver disease in patients with progressively worsening insulin resistance may not be recognized until patients develop manifestations of the metabolic syndrome such as diabetes, hypertension, hyperlipidemia, and vascular disease. It was aimed to investigate whether three angiotensin II type 1 receptor antagonists (ARBs) (olmesartan, losartan, and valsartan) had preventive effect against hepatic fibrosis and this was a common characteristic among ARBs. In current study, 25 adult male rats were used and divided into five groups: the non-diabetic healthy group, alloxan induced diabetic (AID) control group, AID losartan group, AID valsartan group and AID olmesartan group. According to numerical density of hepatocytes, significant difference was found between the non-diabetic healthy group and diabetic control group. All treatments groups were significant when compared to diabetic control group. In diabetic control group it was examined swelling, irregular cristae arrangement in some of mitochondria. It was also determined mitochondria membrane degeneration in some areas of section profiles. In diabetic rats treated with losartan group, there were necrotic hepatocytes. In diabetic rats treated with valsartan group, predominantly, findings were similar to losartan group. In diabetic rats treated with olmesertan group, plates of hepatocytes were quite regular. There were hardly necrotic cells. Not only other organelles such as RER, SER and lysosom but also mitochondrial structures had normal appearance. In the diabetic control group electron microscopy revealed edema in both the cytoplasm and perinuclear area and the nuclear membranes appeared damaged. In conclusion, it was established that the most protective ARB the liver in diabetic rats was olmesartan, followed by losartan.

Rosiglitazone versus rosiglitazone and metformin versus rosiglitazone and losartan in the treatment of nonalcoholic steatohepatitis in humans: a 12-month randomized, prospective, open- label trial

Medication combinations that improve the efficacy of thiazolidinediones or ameliorate weight-gain side effects of therapy represent an attractive potential treatment for (NASH). The aim of this randomized, open-label trial was to assess the efficacy of rosiglitazone and metformin in combination versus rosiglitazone and losartan, compared to rosiglitazone alone, after 48 weeks of therapy. A total of 137 subjects with biopsy-proven NASH were enrolled and randomly assigned to receive either 4 mg twice-daily of rosiglitazone, 4 mg of rosiglitazone and 500 mg of metformin twice-daily, or 4 mg of rosiglitazone twice-daily and 50 mg of losartan once-daily for 48 weeks. Patients were screened for other etiologies of chronic liver disease, including daily alcohol intake in excess of 20 g. Repeat liver biopsy was performed after 48 weeks of therapy and reviewed in a blinded fashion by a single expert hepatopathologist. The primary aim of the study was to assess for differences between treatment groups in the improvement of steatosis, hepatocellular inflammation, and fibrosis. In total, 108 subjects completed the trial. Primary outcome revealed no significant difference between treatment groups in all histologic parameters (steatosis, P = 0.137; hepatocellular inflammation, P = 0.320; fibrosis, P = 0.229). Overall improvement in steatosis, hepatocellular inflammation, ballooning degeneration, and fibrosis was observed (P ≤ 0.001). Serum aminotransferases were reduced in all three groups (P < 0.001 within treatment, P > 0.05 between groups). Metformin did not significantly mitigate weight gain (P = 0.051).

CONCLUSIONS

Forty-eight weeks of combination therapy with rosiglitazone and metformin or rosiglitazone and losartan confers no greater benefit than rosiglitazone alone with respect to histopathology.

Protective effects of curcumin, α-lipoic acid, and N-acetylcysteine against carbon tetrachloride-induced liver fibrosis in rats

Liver fibrosis is a major health problem that can lead to the development of liver cirrhosis and hepatocellular carcinoma. On the other hand, several antioxidants have been shown to possess protective effect against liver fibrosis. Therefore, in the present work, the effectiveness of curcumin, α-lipoic acid, and N-acetylcysteine in protecting against carbon tetrachloride (CCl(4))-induced liver fibrosis as well as the mechanism(s) implicated in this protective effect was studied. The antioxidants used in this study resulted in hepatoprotective effect as evident by substantial decreases in collagen deposition in histopathological examinations in addition to significant decrease in serum levels of alanine aminotransferase, aspartate aminotransferase, gamma glutamyl transpeptidase, bilirubin, and transforming growth factor-alpha (TGF-α) as well as hepatic malondialdehyde concentration, with a concurrent increase in serum matrix metalloproteinase-13 (MMP-13) and hepatic reduced glutathione (GSH) levels as compared to CCl(4) fibrotic group. In conclusion, curcumin, α-lipoic acid, and N-acetylcysteine protect rats against CCl(4)-induced liver fibrosis most possibly through their antioxidant activities and their capacities to induce MMP-13 and to inhibit TGF-α levels.

Telmisartan improves nonalcoholic steatohepatitis in medaka (Oryzias latipes) by reducing macrophage infiltration and fat accumulation

We investigated the efficacy of the antihypertensive drug telmisartan (Tel) and the mechanisms underlying the progression from simple steatosis to nonalcoholic steatohepatitis (NASH) in a medaka (Oryzias latipes) NASH model. We used the NASH activity score (NAS) developed in humans to assess the histology of the medaka NASH model and found that NAS increased with time. Further, TUNEL-positive apoptosis hepatocytes were found in the medaka NASH model. Tel administration resulted in the increased expression of liver peroxisome proliferator-activated receptor-γ, carnitine palmitoyltransferase 1 and acyl-CoA oxidase 1 and decreased the number of 8-hydroxydeoxyguanosine-positive hepatocytes and the migration of macrophages positive for diastase-periodic-acid-Schiff. Medaka NAS was improved by Tel administration but fatty acid content was not affected. Tel reduced the infiltration of macrophages into the liver and ameliorated NASH pathology.

The challenge of developing novel pharmacological therapies for non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term for a series of hepatic pathologies that begin with relatively benign steatosis and can, with appropriate triggers, lead to the serious entity of non-alcoholic steatohepatitis (NASH). This sets the stage for liver fibrosis and finally the development of cirrhosis in up to 20% of patients with NASH. NAFLD, already among the most common diseases in industrialized countries, is increasing in prevalence and roughly affects 30% of US adults and 10% of US children alone. NAFLD is strongly associated with insulin resistance (IR) and represents the hepatic manifestation of the metabolic syndrome. Indeed, treatments aimed at reducing IR are the current mainstay of therapeutic approaches to NAFLD. While lifestyle interventions may produce limited degrees of success, there remains an urgent need for improved pharmacological therapies. Emerging diagnostic and therapeutic opportunities as well as future developments in NAFLD, NASH and liver fibrosis were discussed by a panel of experts and are presented herein. Promising novel therapeutic targets include inhibitors of dipeptidyl peptidase 4 and the renin-angiotensin system. However, improved non-invasive technologies to diagnose and stage NAFLD are needed. Combined with a better understanding of the pathophysiological processes that underlie the mechanisms of hepatic fibrogenesis in NASH, rapid clinical validation of novel therapies is expected.

Diagnosis and treatment of portal hypertension

Major progress has been made in the area of diagnosis and treatment of portal hypertension. Multi-detector row computed tomography (MD-CT) enabled the revelation of the precise overview of portal hemodynamics and was applied into the decision of therapeutic strategies. A noninvasive liver stiffness measurement device, transient elastography, is expected to be applied in the prediction of existence of esophageal varices. Balloon-occluded retrograde transvenous obliteration (B-RTO) is performed mainly in Japan to eradiate the fundic varices and high eradiation rate and low recurrence rate are reported. Partial splenic embolization (PSE) has been performed to improve hypersplenism without serious side-effect and excellent result is reported. Angiotensin receptor blockers (ARBs) are promising drugs for its portal hypotensive effect and antifibrotic effect and more investigation is necessary. Anti-fibrotic therapy, including autologous bone marrow therapy, has the possibility to improve not only liver fibrosis but also portal hypertension.

Effects of losartan on hepatic expression of nonphagocytic NADPH oxidase and fibrogenic genes in patients with chronic hepatitis C

Angiotensin II promotes liver fibrogenesis by stimulating nonphagocytic NADPH oxidase (NOX)-induced oxidative stress. Angiotensin II type 1 (AT1) receptor blockers attenuate experimental liver fibrosis, yet their effects in human liver fibrosis are unknown. We investigated the effects of losartan on hepatic expression of fibrogenic, inflammatory, and NOX genes in patients with chronic hepatitis C (CHC). Fourteen patients with CHC and liver fibrosis received oral losartan (50 mg/day) for 18 mo. Liver biopsies were performed at baseline and after treatment. The degree of inflammation and fibrosis was evaluated by histological analysis (METAVIR). Collagen content was measured by morphometric quantification of Sirius red staining. Overall collagen content and fibrosis stage remained stable in the whole series, yet the fibrosis stage decreased in seven patients. Inflammatory activity improved in seven patients. The effect of losartan on hepatic expression of 31 profibrogenic and inflammatory genes and components of the NOX complex was assessed by quantitative PCR. Losartan treatment was associated with a significant decrease in the expression of several profibrogenic and NOX genes including procollagen alpha1(I) and alpha1(IV), urokinase-type plasminogen activator, metalloproteinase type 2, NOX activator 1 (NOXA-1) and organizer 1 (NOXO-1), and Rac-1. Losartan was well tolerated in all patients and was effective in attenuating the activity of the systemic renin-angiotensin system. No effects on serum liver tests or viral load were observed. We conclude that prolonged administration of losartan, an oral AT1 receptor blocker, is associated with downregulation of NOX components and fibrogenic genes in patients with CHC. Controlled studies are warranted to assess the effect of AT1 receptor blockers in chronic liver injury.

Telmisartan attenuates progression of steatohepatitis in mice: role of hepatic macrophage infiltration and effects on adipose tissue

BACKGROUND/AIMS

Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis (NASH) are the hepatic manifestation of metabolic syndrome. However, its therapeutic strategy has not been established. Recently, an angiotensin II type 1 receptor blocker, telmisartan (Tel), has received a great deal of attention as a therapeutic tool for metabolic syndrome. The aim of this study was to investigate the efficacy and mechanisms of Tel on a murine NASH model.

METHODS

C57BL/6 mice were fed a methionine- and choline-deficient high-fat diet (MCDHF) or a standard diet with/without the administration of Tel (10 mg/kg/day) for 8 weeks.

RESULTS

MCDHF feeding induced marked steatohepatitis with macrophage infiltration. Tel attenuated liver steatosis with decreased hepatic triglycerides (P<0.05) and fibrogenesis with decreased type I collagen and transforming growth factor-beta1 mRNA expressions (P<0.05). Tel also suppressed the infiltration of macrophages into the liver and decreased hepatic monocyte chemoattractant protein-1 and its receptor (CC-chemokine receptor 2; CCR2) mRNA expressions, especially CCR2. In vitro, Tel suppressed CCR2 expression, which was induced by low-density lipoprotein. The size of adipocyte in visceral fat tissue was reduced with an increased serum adiponectin concentration in the Tel group.

CONCLUSIONS

In this study, we revealed that Tel attenuated steatohepatitis progression by suppressing the macrophage infiltration into the liver. Tel also affected the reduction of adipocyte size and elevation of serum adiponectin. Tel might serve as a new therapeutic strategy for NASH.

Deletion of angiotensin II type I receptor reduces hepatic steatosis

BACKGROUND/AIMS

A distinct subgroup of angiotensin II type 1 receptor (AT1R) blockers (ARBs) have been reported to suppress the development of hepatic steatosis. These effects were generally explained by selective peroxisome proliferator-activated receptor (PPAR) gamma modulating properties of ARBs, independent of their AT1R blocking actions. Here, we provide genetic evidence of the direct role for AT1R in hepatic steatosis.

METHODS

The effect of AT1R deletion on steatohepatitis was investigated in AT1a(-/-) mice. Furthermore, the influence of AT1R inhibition by telmisartan as well as gene silencing of AT1R by siRNA was assessed in an in vitro experiment using HepG2 cells.

RESULTS

Compared to wild-type (WT), AT1a(-/-) mice fed methionine-choline deficient (MCD) diet resulted in negligible lipid accumulation in the liver with marked induction of PPARalpha mRNA. In vitro experiments also demonstrated reduced cellular lipid accumulation by telmisartan and AT1R knockdown following exposure of long chain fatty acids. This is presumably explained by the observation that the expression of PPARalpha and its target genes were significantly up-regulated in specific siRNA treated HepG2 cells.

CONCLUSIONS

Our data indicate, in addition to pharmacological effect of ARBs on PPARgamma activation, a key biological role for AT1R in the regulation of hepatic lipid metabolism.

Chronic treatment with angiotensin AT1 receptor antagonists reduced serum but not bone TGF-beta1 levels in ovariectomized rats

Approximately 50% of hypertensive patients are postmenopausal women; therefore, any antihypertensive therapy must not adversely affect bone loss in this population. Recently, however, concern has been raised that use of angiotensin AT1 receptor antagonists may increase the tendency to develop postmenopausal osteoporosis by decreasing transforming growth factor-beta1 (TGF-beta1), which has been implicated in bone mass maintenance. In the present study, we selected telmisartan and valsartan as representatives of angiotensin AT1 receptor antagonists and used ovariectomized (OVX) rats as a model of human postmenopausal osteoporosis. After 3 months treatment with telmisartan (5 mg/kg daily) or valsartan (10 mg/kg daily), OVX rats showed no signs of adverse effects on bone mineral density of the lumbar vertebrae (L1-L5) or the total femur, nor did treatment affect serum levels of osteocalcin and osteoclast-derived tartrate-resistant acid phosphatase (TRACP-5b). Bone TGF-beta1 content remained unchanged, although treatment with telmisartan and valsartan significantly reduced serum TGF-beta1 levels (p < 0.05). In conclusion, chronic treatment with angiotensin AT1 receptor antagonists reduced serum but not bone TGF-beta1 levels and did not accelerate ovariectomy-induced bone loss in rats.

Nonalcoholic fatty liver disease in type 2 diabetes mellitus

PURPOSE OF REVIEW

To increase awareness about the close interrelationship between nonalcoholic fatty liver disease and type 2 diabetes mellitus, and of recent diagnostic and treatment advances in the field.

RECENT FINDINGS

The perception of nonalcoholic fatty liver disease as an uncommon and benign condition is rapidly changing. Approximately 70% of persons with type 2 diabetes mellitus have a fatty liver and the disease follows a more aggressive course with necroinflammation and fibrosis (i.e. nonalcoholic steatohepatitis) in diabetes. New evidence suggests that it is not steatosis per se but the development of lipotoxicity-induced mitochondrial dysfunction and activation of inflammatory pathways that leads to progressive liver damage. Nonalcoholic steatohepatitis is a leading cause of end-stage liver disease and contributes to cardiovascular disease in patients with type 2 diabetes mellitus. Because nonalcoholic steatohepatitis may develop even in the presence of normal liver transaminases, a liver biopsy is still necessary for a definitive diagnosis. However, new imaging methods and plasma biomarkers are emerging as alternative diagnostic tools. Lifestyle intervention is the gold standard for the management of nonalcoholic steatohepatitis. Recent randomized controlled trials suggest thiazolidiendiones are promising therapeutic agents.

SUMMARY

Nonalcoholic steatohepatitis is a frequently overlooked and potentially severe complication of type 2 diabetes mellitus. Patients may benefit from its early diagnosis and treatment.

Angiotensin-receptor blockers as therapy for mild-to-moderate hypertension-associated non-alcoholic steatohepatitis

AIM: To evaluate insulin resistance, cytolysis and non-alcoholic steatohepatitis (NASH) score (NAS) using the Kleiner and Brunt criteria in 54 patients with NASH and mild-to-moderate hypertension, treated with telmisartan vs valsartan for 20 mo.

METHODS: All patients met the NCEP-ATP III criteria for metabolic syndrome. Histology confirmed steatohepatitis, defined as a NAS greater than five up to 3 wk prior inclusion, using the current criteria. Patients with viral hepatitis, chronic alcohol intake, drug abuse or other significant immune or metabolic hepatic pathology were excluded. Subjects were randomly assigned either to the valsartan (V) group (standard dose 80 mg o.d., n = 26), or to the telmisartan (T) group (standard dose 20 mg o.d., n = 28). Treatment had to be taken daily at the same hour with no concomitant medication or alcohol consumption allowed. Neither the patient nor the medical staff was aware of treatment group allocation. Paired liver biopsies obtained at inclusion (visit 1) and end of treatment (EOT) were assessed by a single blinded pathologist, not aware of patient or treatment group. Blood pressure, BMI, ALT, AST, HOMA-IR, plasma triglycerides (TG) and total cholesterol (TC) were evaluated at inclusion and every 4 mo until EOT (visit 6).

RESULTS: At EOT we noticed a significant decrease in ALT levels vs inclusion in all patients and this decrease did not differ significantly in group T vs group V. HOMA-IR significantly decreased at EOT vs inclusion in all patients but in group T, the mean HOMA-IR decrease per month was higher than in group V. NAS significantly diminished at EOT in all patients with a higher decrease in group T vs group V.

CONCLUSION: Angiotensin receptor blockers seem to be efficient in hypertension-associated NASH. Telmisartan showed a higher efficacy regarding insulin resistance and histology, perhaps because of its specific PPAR-gamma ligand effect.

Continuos intravenous infusion of atrial natriuretic peptide (ANP) prevented liver fibrosis in rat

The atrial natriuretic peptide (ANP) are used as the acute heart failure treatment in clinical and reported the suppression of fibrosis in the heart, lung recently. The aim of this study was to analyze the suppressive effect of liver fibrosis about ANP. In vitro, rat hepatic stellate cell line (HSC-T6) were treated with ANP. In vivo, Wister rats were injected with dimethylnitrosamine (DMN) twice a week via intra-peritoneal for 4 weeks. ANP group was given by continuance intravenous dosage system used 24h infusion pump for 3 weeks after 1 week of DMN administration. In vitro, ANP suppressed alpha-SMA expression and was inhibited the growth of HSC, and reduced the expression of type 1 procollagen, TIMP-1, -2 expression. In vivo, The ANP group showed lower serum AST, ALT, HA level. Liver fibrosis was suppressed by ANP. ANP also decreased gene expression of type 1 procollagen, TIMP-1, -2 and alpha-SMA, TGF-beta1 expression. Our results showed that continuous ANP infusion has the specific capacity of inhibiting HSC activation and protecting hepatocytes and the useful capacity to suppress the liver fibrosis.

Current and future anti-fibrotic therapies for chronic liver disease

Chronic injury results in a wound healing response that eventually leads to fibrosis. The response is generalized, with features common among multiple organ systems. In the liver, various different types of injury lead to fibrogenesis, implying a common pathogenesis. Although several specific therapies for patients who have different liver diseases have been successfully developed, including antiviral therapies for those who have hepatitis B and hepatitis C virus infection, specific and effective antifibrotic therapy remains elusive. Over the past 2 decades, great advances in the understanding of fibrosis have been made and multiple mechanisms underlying hepatic fibrogenesis uncovered. Elucidation of these mechanisms has been of fundamental importance in highlighting novel potential therapies. Preclinical studies have indicated several putative therapies that might abrogate fibrogenesis. This article emphasizes mechanisms underlying fibrogenesis and reviews available and future therapeutics.

Cytokines and renin-angiotensin system signaling in hepatic fibrosis

Hepatic fibrosis is the result of a complex interplay between resident hepatic cells, infiltrating inflammatory cells, and a number of locally acting peptides called cytokines. Key mediators include transforming growth factor b1, vasoactive substances, adipokines, inflammatory cytokines and chemokines. Angiotensin II, the main effector of the renin-angiotensin system, is a true cytokine that plays a major role in liver fibrosis. Angiotensin II is locally synthesized in the injured liver and induces profibrogenic actions in hepatic stellate cells. Drugs blocking the renin-angiotensin system are promising antifibrotic agents. There are multiple signal transduction pathways involved in cytokine signaling. Drugs interfering intracellular pathways involved in increased collagen production are potential therapies for liver fibrosis.

Angiotensin receptor blockers in the treatment of NASH/NAFLD: could they be a first-class option?

Nonalcoholic fatty liver disease (NAFLD) is a condition pathogenically linked to metabolic syndrome (MS) by insulin resistance (IR), and characterized by hepatic steatosis in the absence of significant alcohol use, hepatotoxicity, and/or other known liver diseases.The principles of NAFLD therapy target IR: the key point of MS. As the renin-angiotensin system (RAS) plays a central role in IR, and subsequently in NAFLD and nonalcoholic steatohepatitis (NASH), an attempt to block the deleterious effects of RAS overexpression seems a logical target. While many potential therapies tested in NASH target only the consequences of this condition, or try to "get rid" of excessive fat, angiotensin receptor blockers (ARBs) could act as an elegant tool for adequate correction of the various imbalances that act in harmony in NASH/NAFLD. Indeed, by inhibiting RAS we can improve the intracellular insulin signaling pathway, better control adipose tissue proliferation and adipokine production, and produce more balanced local and systemic levels of various cytokines. At the same time, by controlling the local RAS in the liver we might be able to prevent at least fibrosis and also slow down the vicious cycle that links steatosis to necroinflammation. By targeting the pancreatic effects of angiotensin we should be able to preserve an adequate insulin secretion and acquire a better metabolic balance.In our opinion there are two major advantages of ARBs that make them a possible therapeutic option for treating NASH and MS: their specific antihypertensive effect, and their impact on liver fibrosis. In light of this, and based on the current evidence (including existent human studies), we can speculate that some ARBs like telmisartan, candesartan, and losartan can be beneficial in treating NASH/NAFLD and its consequences, and further larger controlled clinical trials will bring consistent data into this field.

Down-regulation of a hepatic transporter multidrug resistance-associated protein 2 is involved in alteration of pharmacokinetics of glycyrrhizin and its metabolites in a rat model of chronic liver injury

Glycyrrhizin (GL) has been used to treat chronic hepatitis in Japan and Europe. It is thought to induce pseudoaldosteronism via inhibition of type 2 11beta-hydroxysteroid dehydrogenase (11beta-HSD2) by glycyrrhetinic acid (GA), a major metabolite of GL. A previous clinical study suggested that 3-monoglucuronyl-glycyrrhetinic acid (3MGA), another metabolite of GL, might play a more important role in the pathogenesis of pseudoaldosteronism. The present study evaluates the pharmacokinetics of GL and its metabolites in rats with chronic liver injury induced by a choline-deficient l-amino acid-defined (CDAA) diet to clarify the relationship between 3MGA and pseudoaldosteronism. In rats fed a CDAA diet, plasma concentrations and urinary eliminations of GL and 3MGA were markedly higher than in the rats fed the control diet; the plasma concentration of GA was unaffected when GL was orally administered. Immunohistochemical analysis revealed the suppression of levels of multidrug resistance-associated protein (Mrp) 2 and its localization in the hepatic tissue of rats fed a CDAA diet. When 3MGA was i.v. injected in rats fed a CDAA diet or injected in Mrp2-dysfunctional Eisai hyperbilirubinemic rats, plasma concentrations of 3MGA were higher, and biliary excretion of 3MGA was lower than in each control group. The results suggested that 3MGA would be excreted to bile via hepatic Mrp2 and that its dysfunction would reduce 3MGA clearance. 3MGA accumulated by liver fibrosis resulted in the increased excretion through renal tubule and might be strongly related to the pathogenesis of pseudoaldosteronism because 11beta-HSD2 is expressed in renal tubular epithelial cells.