Dipeptidyl peptidase-4 inhibitor attenuates hepatic fibrosis via suppression of activated hepatic stellate cell in rats.

BACKGROUND: Dipeptidyl peptidase-4 inhibitor (DPP4-I) is clinically used as a new oral antidiabetic agent. Although DPP4 is reportedly associated with the progression of chronic liver diseases, the effect of DPP4-I on liver fibrosis development is still obscure. This study was designed to elucidate the effect of DPP4-I on liver fibrosis development in conjunction with the activated hepatic stellate cells (Ac-HSCs). METHODS: The antifibrotic effect of DPP4-I was assessed in vivo and in vitro using porcine serum-induced experimental liver fibrosis model. DPP4-I, sitagliptin, at a clinically comparable low dose was administered by gavage daily. RESULTS: DPP4-I significantly attenuated liver fibrosis development along with the suppression of hepatic transforming growth factor (TGF)-ß1, total collagen, and tissue inhibitor of metalloproteinases-1 in a dose-dependent manner. These suppressive effects occurred almost concurrently with the attenuation of HSCs activation. Our in vitro studies showed that DPP4-I inhibited platelet-derived growth factor-BB-mediated proliferation of the Ac-HSCs as well as upregulation of TGF-ß1 and α1(I)-procollagen at magnitudes similar to those of the in vivo studies. The inhibitory effects of DPP4-I against HSCs proliferation and fibrogenic gene expression are mediated through the inhibition of the phosphorylation of ERK1/2, p38 and Smad2/3, respectively. CONCLUSIONS: DPP4-I markedly inhibits liver fibrosis development in rats via suppression of HSCs proliferation and collagen synthesis. These suppressive effects are associated with dephosphorylation of ERK1/2, p38 and Smad2/3 in the HSCs. Since DPP4-I is widely used in clinical practice, this drug may represent a potential new therapeutic strategy against liver fibrosis in the near future.

Direct renin inhibitor, aliskiren, attenuates the progression of non-alcoholic steatohepatitis in the rat model.

AIM: Renin is a rate-limiting enzyme of the renin-angiotensin system (RAS), and several reports have shown that renin plays an important role in several pathological processes. Although RAS is known to play a pivotal role in the progression of non-alcoholic steatohepatitis (NASH), the role of renin is still obscure. The aim of the current study was to examine the effect of the clinically used direct renin inhibitor (DRI), aliskiren, on the progression of NASH in a rat model. METHODS: The effects of DRI on the choline-deficient L-amino acid-defined (CDAA) diet-induced rat NASH model was examined in conjunction with the activated hepatic stellate cells (Ac-HSC) and neovascularization, both of which are known to play important roles in liver fibrosis development and hepatocarcinogenesis, respectively. RESULTS: DRI exerted a marked inhibitory effect against liver fibrosis development and glutathione-S-transferase placental form (GST-P) positive preneoplastic lesions along with suppression of the Ac-HSC and neovascularization in a dose-dependent manner. DRI also inhibited the hepatic expressions of transforming growth factor-beta 1 (TGF-beta 1), angiotensin-II (AT-II) and vascular endothelial growth factor (VEGF). These results indicated that renin played a pivotal role in the liver fibrosis development and hepatocarcinogenesis of NASH. CONCLUSION: Because DRI is already widely used in the clinical practice with safety, this drug may represent a potential new strategy against the progression of NASH in the future.

Large cell neuroendocrine carcinoma presenting with neck swelling in the submandibular gland: a case report.

INTRODUCTION: Large cell neuroendocrine carcinoma in the salivary glands is rare. We report a second case of large cell neuroendocrine carcinoma of the submandibular gland diagnosed at autopsy, and a review of the literature. CASE PRESENTATION: A 68-year-old Japanese man was referred to our hospital for thorough investigation of swelling on the right side of his neck. Fine-needle aspiration cytology of the cervical mass suggested poorly differentiated metastatic carcinoma. The primary tumor could not be detected by several examinations. One month after admission, he died of cancer. An autopsy was performed, and it revealed a tumor of the right submandibular gland. The histopathological diagnosis was large cell neuroendocrine carcinoma of the submandibular gland. CONCLUSION: To the best of our knowledge, only eight cases of large cell neuroendocrine carcinoma in the salivary glands, including our case, have been reported. This report indicates total biopsy and immunohistochemistry are necessary for diagnosing large cell neuroendocrine carcinoma properly.

Cross talk between toll-like receptor-4 signaling and angiotensin-II in liver fibrosis development in the rat model of non-alcoholic steatohepatitis.

BACKGROUND AND AIM: The innate immune system, including toll-like receptor-4 (TLR4) signaling cascade and angiotensin-II (AT-II) play important roles in the progression of liver fibrosis development; the cross talk between TLR4 and AT-II has not been elucidated yet. The aim of the current study was to elucidate the effect of AT-II type 1 receptor blocker (ARB), on the liver fibrosis development, especially in conjunction with the interaction of TLR4 and AT-II in the rat model of non-alcoholic steatohepatitis. METHODS: Fischer 344 rats were fed a choline-deficient, L-amino-acid-defined diet for 8 weeks and the effects of losartan were elucidated in conjunction with activated hepatic stellate cells (Ac-HSC) activation, TLR4, nuclear factor-κB (NF-κB), and transforming growth factor-ß (TGF-ß) expressions. In vitro study was carried out to elucidate the effect of AT-II on several indices including TLR4, myeloid differentiation factor 88, NF-κB, and TGF-ß expressions in the rat HSC. RESULTS: ARB markedly inhibited liver fibrosis development along with suppression of the number of Ac-HSC and TGF-ß. These inhibitory effects of ARB were almost in parallel with suppression of the hepatic TLR4 and NF-κB expressions. This in vitro study showed that AT-II significantly augmented the TLR4 expression in a dose- and time-dependent manner via AT-II type 1 receptor in the Ac-HSC. AT-II also augmented the lipopolysaccharide-induced myeloid differentiation factor 88 (MyD88), NF-κB, and TGF-ß and these increments were attenuated by treatment with ARB. CONCLUSIONS: These studies indicated that the cross talk between TLR4 signaling cascade and AT-II plays a pivotal role in liver fibrosis development in non-alcoholic steatohepatitis.

Dual blockade of angiotensin-II and aldosterone suppresses the progression of a non-diabetic rat model of steatohepatitis.

AIM: Both angiotensin-II (AT-II) and aldosterone (Ald) play pivotal roles in the pathogenesis of diseases in several organs including the liver. We previously reported that suppression of AT-II and Ald with angiotensin-converting enzyme inhibitor (ACE-I) and selective Ald blocker (SAB), respectively, attenuated the rat liver fibrogenesis and hepatocarcinogenesis. The aim of our current study was to elucidate the combined effects of ACE-I and SAB in the progression of a non-diabetic rat model of steatohepatitis, and the possible mechanisms involved. METHODS: In the choline-deficient L-amino acid-defined (CDAA) diet-induced model, the effects of ACE-I and SAB on liver fibrosis development and hepatocarcinogenesis were elucidated, especially in conjunction with neovascularization. RESULTS: Treatment with both ACE-I and SAB suppressed the development of liver fibrosis and glutathione-S-transferase placental form (GST-P) positive pre-neoplastic lesions. The combined treatment with both agents exerted more inhibitory effects as compared with either a single agent along with suppression of the activated hepatic stellate cells (Ac-HSC) and neovascularization, both of which play important roles in these processes. Our in vitro study showed that AT-II type 1 receptor blocker (ARB) and SAB inhibited Ac-HSC proliferation and in vitro angiogenesis along with suppression of the in vivo studies. CONCLUSION: Dual blockade of AT-II and Ald suppresses the progression of a non-diabetic rat model of steatohepatitis. Because both agents are widely and safely used in clinical practice, this combination therapy could be an effective new strategy against steatohepatitis in the future.

A histologically proven case of progressive liver sarcoidosis with variceal rupture.

Sarcoidosis is a chronic multi-systemic granulomatous disease, and liver involvement frequently occurs. in most cases, no evidence of liver dysfunction is observed, and portal hypertension due to sarcoid liver diseases is a rareoccurrence. Moreover, no case of liver sarcoidosis has ever been reported with confirmation of the disease progression. Herein we describe a patient having hepatic sarcoidosis with severe portal hypertension and liver dysfunction. The diagnosis was histologically confirmed from granulomatous status to established liver cirrhosis over 10 years. A 46-year-old woman developed massive hematemesis due to the rupture of gastric cardial varices. She underwent emergency endoscopic injection sclerotherapy, and clear evidence of chronic hepatic failure. Twelve years ago, she was diagnosed as having sarcoidosis with respiratory clinicalsymptoms. Liver biopsy revealed asymptomatic incidental granulomas without fibrosis development. After a couple of years, features of liver dysfunction were manifest and progressed. Ten years after the first biopsy, a second liver biopsy was performed, and well established dense fibrosis was revealed. Although significant liver dysfunction with portal hypertension is rarely seen in sarcoidosis, this case indicates that we have to consider the possibility that sarcoidosis may cause end-stage liver cirrhosis.

A case of lobulated and pedunculated duodenal hyperplastic polyp treated with snare polypectomy.

We report herein the case of a lobulated and pedunculated hyperplastic polyp in the third portion of the duodenum causing anemia and occult blood in stools, which was detected by capsule endoscopy (CE) and treated with snare polypectomy. A 71-year-old man was referred to our hospital because of anemia and occult blood in stools. Three months earlier, he had been admitted to another hospital because of hemorrhage from gastric antral vascular ectasia (GAVE). Despite being treated for GAVE, hemoglobin decreased gradually. Esophagogastroduodenoscopy (EGD) and colonoscopy revealed no source of bleeding. However, CE revealed a polyp at the distal duodenum. Barium meal and EGD revealed a lobulated and pedunculated polyp in the third portion of the duodenum. The polyp was treated with snare polypectomy. Histopathological examination of the polyp revealed hyperplasia. After treatment of the polyp, the anemia improved gradually. To our knowledge, there are only 6 reported cases of a duodenal hyperplastic polyp, including our case. The polyp was pedunculated in only 2 cases and lobulated only in our case. Moreover, our case was diagnosed by CE. When a patient presents with anemia or obscure gastrointestinal bleeding undiagnosed by EGD and colonoscopy, CE is useful for detecting the bleeding lesion.

Cocktail therapy with a combination of interferon, ribavirin and angiotensin-II type 1 receptor blocker attenuates murine liver fibrosis development.

An effective therapeutic strategy for suppressing liver fibrosis development should improve the overall prognosis of patients with chronic liver diseases. Despite efforts to develop anti-fibrotic agents, no drugs have yet been approved as anti-fibrotic treatments for humans. An alternative strategy may be to employ a clinically available agent that also exhibits anti-fibrotic activities, for which the safety of long-term administration has been proven. The aim of the current study was to elucidate the combined effect of clinically used interferon (IFN), ribavirin (Rib) and angiotensin-II receptor blocker (ARB) on liver fibrosis development in mice. A model of CCl4-induced hepatic fibrosis was used to assess the effect of IFN, Rib and ARB. IFN, Rib and ARB were administered after a two-week treatment with CCl4, and the hepatic indices of fibrosis were assessed at eight weeks. Single treatment with IFN, Rib or ARB at the clinically available comparable doses significantly attenuated the liver fibrogenesis associated with the suppression of the number of α-smooth muscle actin positive cells, and the hepatic transforming growth factor-ß (TGF-ß) mRNA. Hepatic neovascularization, which is also known to play a pivotal role in liver fibrogenesis, and vascular endothelial growth factor (VEGF), a potent angiogenic factor, were also markedly inhibited. Combination treatment with any two agents exerted a more potent inhibitory effect than any single treatment. Moreover, the triple cocktail treatment revealed further suppressive effects than any two agent combination. Furthermore, in vitro studies showed that similar combined effects were observed on the proliferation and TGF-ß mRNA expression of activated hepatic stellate cells and endothelial cell tube formation. These results indicate that the cocktail combination treatment of clinically used IFN, Rib and ARB may provide a new strategy for anti-liver fibrosis therapy.

Combination treatment of angiotensin II type I receptor blocker and new oral iron chelator attenuates progression of nonalcoholic steatohepatitis in rats.

Angiotensin II type I receptor blocker and iron chelator reportedly exert suppressive effects on nonalcoholic steatohepatitis (NASH) progression, including liver fibrosis and hepatocarcinogenesis. The aim of this study was to elucidate the combined effect of losartan (LOS), an angiotensin II type I receptor blocker, and deferasirox (DSX), a newly developed oral iron chelator, on the progression of NASH in rats. To induce NASH, F344 rats were fed a choline-deficient l-amino acid-defined diet for 12 wk, and the effects of LOS and DSX at clinically comparable low doses were elucidated in conjunction with oxidative stress, neovascularization, and hepatic stellate cells (HSC) activation, all known to play important roles in the progression of NASH. Treatment with both LOS and DSX suppressed choline-deficient L-amino acid-defined diet-induced liver fibrosis development and hepatocarcinogenesis. This combination treatment exerted a stronger inhibitory effect compared with treatment with a single agent. These inhibitory effects occurred almost concurrently with the suppression of oxidative stress, neovascularization, and HSC activation. Our in vitro study demonstrated that LOS and DSX inhibited angiotensin II-induced proliferation, transforming growth factor-ß(1) expression of activated HSC, and in vitro angiogenesis. These results indicated that dual inhibition by combined treatment of LOS and DSX attenuated the progression of NASH. Since both agents are widely used in clinical practice, this combination therapy may represent a potential new strategy against NASH in the near future.

Salvage living donor liver transplantation after percutaneous transluminal angioplasty for recurrent Budd-Chiari syndrome: a case report.

INTRODUCTION: Budd-Chiari syndrome is a very rare pathological entity that ultimately leads to liver failure. Several therapeutic modalities, including percutaneous transluminal angioplasty, have been attempted to save the life of patients with Budd-Chiari syndrome. Few reports have described a salvage living donor liver transplantation performed after percutaneous transluminal angioplasty in a patient with acute Budd-Chiari syndrome. CASE PRESENTATION: A 26-year-old Japanese man developed severe progressive manifestations, such as massive ascites and hematemesis due to rupture of esophageal varices. After making several investigations, we diagnosed the case as Budd-Chiari syndrome. We first performed percutaneous transluminal angioplasty to dilate a short-segment stenosis of his inferior vena cava. The first percutaneous transluminal angioplasty greatly improved the clinical manifestations. However, after a year, re-stenosis was detected, and a second percutaneous transluminal angioplasty failed to open the severe stricture of his inferior vena cava. Since our patient had manifestations of acute liver failure, we decided to perform salvage living donor liver transplantation from his brother. The transplantation was successfully performed and all clinical manifestations were remarkably alleviated. CONCLUSION: In cases of recurrent Budd-Chiari syndrome, the blocked hepatic venous outflow is not always relieved, even with invasive therapies. We have to take into account the possibility of adopting alternative salvage therapies if the first therapeutic modalities fail. When invasive therapy such as percutaneous transluminal angioplasty fails, liver transplantation should be considered as an alternative option.

Soluble VEGF receptor-2 may be a predictive marker of anti-angiogenic therapy with clinically available safe agents.

The identification of biomarkers of anti-angiogenic therapy that predict clinical benefit is of vital importance. We previously reported that a combination treatment with clinically available safe agents, specifically angiotensin-converting enzyme inhibitor (ACE-I) and vitamin K (VK), inhibited the cumulative recurrence of hepatocellular carcinoma (HCC) via suppression of the vascular endothelial growth factor (VEGF). The present study aimed to identify non-invasive biological markers that predict the clinically beneficial effect of this combination regimen. A combination of ACE-I (perindopril; 4 mg/day) and VK (menatetrenone; 45 mg/day) was administered for 54 months following curative therapy for HCC. The cumulative recurrence and several indices, which are reportedly considered as biological markers of anti-angiogenic therapies, were analyzed. The combined treatment of ACE-I and VK markedly inhibited the cumulative recurrence of HCC during the 54-month follow-up. The serum VEGF and soluble VEGF receptor (sVEGFR)-2 were significantly suppressed with this combination regimen, whereas sVEGFR-1 was not. In HCC patients without recurrence, a significant suppression of VEGF and sVEGFR-2 was achieved within 6 and 3 months after treatment, respectively. In conclusion, the combination treatment of ACE-I and VK is a potentially novel anti-angiogenic strategy for secondary chemoprevention against HCC since the two agents are widely used in clinical practice without serious side effects. Furthermore, sVEGFR-2 may become a useful clinical predictive marker of this combination treatment.

The vascular endothelial growth factor (VEGF) receptor-2 is a major regulator of VEGF-mediated salvage effect in murine acute hepatic failure.

Although administration of the vascular endothelial growth factor (VEGF), a potent angiogenic factor, could improve the overall survival of destroyed sinusoidal endothelial cells (SEC) in chemically induced murine acute hepatic failure (AHF), the mechanistic roles of the VEGF receptors have not been elucidated yet. The respective roles of VEGF receptors; namely, Flt-1 (VEGFR-1: R1) and KDR/Flk-1 (VEGFR-2: R2), in the D-galactosamine (Gal-N) and lipopolysaccharide (LPS)-induced AHF were elucidated with specific neutralizing monoclonal antibody against R1 and R2 (R1-mAb and R2-mAb, respectively). The serum ALT elevation, with a peak at 24 h after Gal-N+LPS intoxication, was markedly augmented by means of the R1-mAb and R2-mAb. The aggregative effect of R2-mAb was more potent than that of R1-mAb, and the survival rate was 70% in the R2-mAb-treated group and 100% in the other groups. The results of SEC destruction were almost parallel to those of the ALT changes. Our in-vitro study showed that R1-mAb and R2-mAb significantly worsened the Gal-N+LPS-induced cytotoxicity and apoptosis of SEC mediated by caspase-3, which were almost of similar magnitude to those in the in-vivo study. In conclusion, these results indicated that R2 is a major regulator of the salvage effect of VEGF on the maintenance of SEC architecture and the anti-apoptotic effects against chemically-induced murine AHF.

Selective aldosterone blocker ameliorates the progression of non-alcoholic steatohepatitis in rats.

Although non-alcoholic steatohepatitis (NASH) may progress to cirrhosis and hepatocellular carcinoma (HCC), no effective therapeutic modalities have been fully established yet. Recent studies have shown that the renin-angiotensin-aldosterone-system plays an important role in NASH. The aim of our current study was to elucidate the effects of aldosterone (Ald) inhibition on the progression of NASH. In the choline-deficient L-amino acid-defined diet-induced rat NASH model, the effects of a clinically used selective Ald blocker (SAB) were elucidated in conjunction with the activated hepatic stellate cells (HSC) and neovascularization, which are both known to play important roles in liver fibrosis development and hepatocarcinogenesis, respectively. Liver fibrosis development and the glutathione-S-transferase placental form-positive pre-neoplastic lesions were both markedly attenuated by SAB along with the suppression of the activated HSC and neovascularization. SAB inhibited the hepatic expression of transforming growth factor-beta 1 and also that of the vascular endothelial growth factor. Our in vitro study showed that SAB also inhibited the Ald-induced HSC proliferation and in vitro angiogenesis in a dose-dependent manner. These results indicated that Ald plays a pivotal role in the progression of NASH. Considering that SAB is already widely used in clinical practice, this drug could represent a potential new strategy against NASH in the future.

Selective aldosterone blocker, eplerenone, attenuates hepatocellular carcinoma growth and angiogenesis in mice.

AIM: The renin-angiotensin-aldosterone system (RAAS) has become known as a prerequisite for tumor angiogenesis, including hepatocellular carcinoma (HCC). Although angiotensin II is known to play an important role in tumor growth and angiogenesis, the role of aldosterone (Ald) is still obscure. The aim of our current study was to elucidate the effect of eplerenone, a clinically used selective Ald blocker (SAB), on murine HCC development especially in conjunction with angiogenesis. METHODS: To create an allograft model, we injected 1 x 10(6) of BNL-HCC cells into the flanks of BALB/c mice. After the tumor was established, SAB was administrated at dose of 100 mg/kg per day. RESULTS: Administration of SAB significantly suppressed HCC development along with inhibition of angiogenesis and expression of the vascular endothelial growth factor (VEGF), a potent angiogenic factor. SAB treatment resulted in a marked increase of apoptosis in the tumor, whereas tumor cell proliferation was not altered. Our in vitro study showed that SAB significantly suppressed the Ald-induced endothelial proliferation and tubular formation through inhibition of phosphorylation of the extracellular signal-regulated kinase 1/2. On the contrary, neither Ald nor SAB affected the proliferation of HCC cells in vitro. CONCLUSION: Ald plays a pivotal role in HCC development through VEGF-mediated tumor angiogenesis, and SAB may be a potential new strategy in HCC therapy in the future.

Attenuation of insulin-resistance-based hepatocarcinogenesis and angiogenesis by combined treatment with branched-chain amino acids and angiotensin-converting enzyme inhibitor in obese diabetic rats.

BACKGROUND: Insulin resistance (IR) is reportedly involved in the progression of hepatocellular carcinoma (HCC). Because neovascularization plays an important role in HCC, including hepatocarcinogenesis, an angiostatic therapy would be a promising approach for chemoprevention against HCC. The aim of the present study was to examine the combined effect of clinically used branched-chain amino acids (BCAAs) and an angiotensin-converting enzyme inhibitor (ACE-I), in conjunction with neovascularization, on hepatocarcinogenesis under the condition of IR. METHODS: The combined effect of the treatment on the development of liver enzyme-altered preneoplastic lesions, angiogenesis, and several indices was elucidated in obese diabetic rats. We also performed several sets of in vitro experiments to examine the mechanisms involved. RESULTS: When used individually, both BCAAs and ACE-I at clinically comparable low doses significantly attenuated the development of preneoplastic lesions, along with the suppression of both angiogenesis and vascular endothelial growth factor (VEGF) expression. The combination treatment with both agents exerted a more potent inhibitory effect than that of either single agent. Our in vitro study showed a similar combined effect on endothelial cell tubule formation. CONCLUSION: This combination regimen showed a marked chemopreventive effect against hepatocarcinogenesis, along with suppression of neovascularization and VEGF expression, in obese diabetic rats. Because both BCAAs and ACE-Is are widely used in clinical practice, this combination therapy may represent a potential new strategy for chemoprevention against IR-based HCC in the future.

Crosstalk between angiogenesis, cytokeratin-18, and insulin resistance in the progression of non-alcoholic steatohepatitis.

AIM: To elucidate the possible crosstalk between angiogenesis, cytokeratin-18 (CK-18), and insulin resistance (IR) especially in patients with non-alcoholic steatohepatitis (NASH). METHODS: Twenty-eight patients with NASH and 11 with simple fatty liver disease (FL) were enrolled in this study and underwent clinicopathological examination. The measures of angiogenesis, CK-18, and IR employed were CD34-immunopositive vessels, CK-18-immunopositive cells, and homeostasis model assessment of IR (HOMA-IR), respectively. The correlations of these factors with NASH were elucidated. RESULTS: Significant development of hepatic neovascularization was observed only in NASH, whereas almost no neovascularization could be observed in FL and healthy liver. The degree of angiogenesis was almost parallel to liver fibrosis development, and both parameters were positively correlated. Similarly, CK-18 expression and HOMA-R were significantly increased in NASH as compared with FL and healthy liver. Furthermore, CK-18 and HOMA-IR were also positively correlated with the degree of neovascularization. CONCLUSION: These results indicate that the crosstalk between angiogenesis, CK-18, and IR may play an important role in the onset and progression of NASH.

Losartan, an angiotensin-II type 1 receptor blocker, attenuates the liver fibrosis development of non-alcoholic steatohepatitis in the rat.

BACKGROUND: Apart from simple steatosis, the non-alcoholic steatohepatitis (NASH) can progress into liver fibrosis and cirrhosis. To date, however, no widely accepted therapeutic modalities have been established against NASH in the clinical practice. To find out promising new therapeutic agents, it is important to employ an appropriate experimental model of NASH, such as association with insulin resistance. FINDINGS: In the current study, we found that losartan, a clinically used angiotensin-II type 1 receptor blocker, significantly attenuated a choline-deficient L-amino acid-defined (CDAA) diet-induced steatohepatitis in obese diabetic- and insulin resistance-associated Otsuka Long-Evans Tokushima Fatty (OLETF) rats. The transforming growth factor-beta, a well-known major fibrogenic cytokine, was also suppressed in a similar magnitude to that of the fibrosis area. Noteworthy was the finding that these inhibitory effects were achieved even at a clinically comparable low dose. CONCLUSION: Since losartan is widely used without serious side effects in the clinical practice, this agent may be an effective new therapeutic strategy against NASH.