Shao-Jung Hsu

Caffeine ameliorates hemodynamic derangements and portosystemic collaterals in cirrhotic rats

Portal hypertension (PH), a pathophysiological derangement of liver cirrhosis, is characterized by hyperdynamic circulation, angiogenesis, and portosystemic collaterals. These may lead to lethal complications, such as variceal bleeding. Caffeine has been noted for its effects on liver inflammation, fibrogenesis, and vasoreactiveness. However, the relevant influences of caffeine in cirrhosis and PH have not been addressed. Spraque‐Dawley rats with common bile duct ligation–induced cirrhosis or sham operation received prophylactic or therapeutic caffeine treatment (50 mg/kg/day, the first or 15th day since operation, respectively) for 28 days. Compared to vehicle (distilled water), caffeine decreased cardiac index, increased systemic vascular resistance, reduced portal pressure (PP), superior mesenteric artery flow, mesenteric vascular density, portosystemic shunting (PSS), intrahepatic angiogenesis, and fibrosis without affecting liver and renal biochemistry. The beneficial effects were reversed by selective adenosine A1 agonist N6‐cyclopentyladenosine (CPA) or A2A agonist GCS21680. Both prophylactic and therapeutic caffeine treatment decreased portal resistance and PP in thioacetamide (200mg/kg, thrice‐weekly for 8 weeks)‐induced cirrhotic rats. Caffeine down‐regulated endothelial nitric oxide synthase, vascular endothelial growth factor (VEGF), phospho‐VEGFR2, and phospho–Akt mesenteric protein expression. Caffeine adversely affected viability of hepatic stellate and sinusoidal endothelial cells, which was reversed by CPA and GCS21680. On the other hand, caffeine did not modify vascular response to vasoconstrictors in splanchnic, hepatic, and collateral vascular beds. Conclusions: Caffeine decreased PP, ameliorated hyperdynamic circulation, PSS, mesenteric angiogenesis, hepatic angiogenesis, and fibrosis in cirrhotic rats. Caffeine may be a feasible candidate to ameliorate PH‐related complications in cirrhosis. (Hepatology 2015;61:1672‐1684)

The influence of sorafenib on hepatic encephalopathy and the mechanistic survey in cirrhotic rats

Eur J Clin Invest 2012; 42 (12): 1309–1316

Endothelin receptor blockers reduce shunting and angiogenesis in cirrhotic rats

Angiogenesis plays a pivotal role in splanchnic hyperaemia and portosystemic collateral formation in cirrhosis. Endothelin‐1 (ET‐1), an endothelium‐derived vasoconstrictor, has also been implicated in the pathogenesis of cirrhosis and portal hypertension.

Effects of simvastatin on the portal-systemic collateral vascular response to endothelin-1 and shunting degree in portal hypertensive rats

Abstract Objective. Endothelin-1 (ET-1) exerts vasoconstrictive effect on portal-systemic collateral vascular bed of portal hypertensive rats. Statins are lipid-lowering agents with nitric oxide (NO)-related vasodilatory effects. Considering NO-associated vascular hyporesponsiveness to vasoconstrictors and shunting formation in portal hypertension, this study investigated the effects of simvastatin on 1) the portal-systemic collateral vascular responsiveness to ET-1 and 2) the portal-systemic shunting degree. Materials/methods. Portal hypertension was induced by partial portal vein ligation (PVL) in Sprague-Dawley rats. Simvastatin (20 mg/kg/day) or distilled water (control) was randomly administered by oral gavage since 2 days prior to until 7 days after PVL. Systemic and portal hemodynamics were measured on the 8th day. In another series, collateral perfusion with Krebs solution at different flow rates was performed to get flow–pressure curves which serve as an index of shunting degree. To survey the direct vascular effect, PVL rats randomly underwent preincubation with 1) Krebs solution, that is, the control group; or Krebs solution plus 2) simvastatin; 3) simvastatin + N ω-nitro-l-arginine (NNA, a NO synthase inhibitor); 4) simvastatin + indomethacin (a cyclooxygenase inhibitor), followed by ET-1 to evaluate the collateral vascular responsiveness. Results. Chronic simvastatin treatment significantly reduced portal pressure. The flow–pressure curves were similar between two groups. Simvastatin preincubation reduced collateral perfusion pressure changes to ET-1 (p < 0.05), which were partially reversed by NNA (p < 0.05), but not by indomethacin. Conclusions. Chronic simvastatin treatment significantly improved portal hypertension. The effect was at least partially exerted by decreased portal-systemic collateral vascular resistance through NO-mediated vascular hyporesponsiveness. The severity of portal-systemic collaterals was not influenced by simvastatin.

Effects of raloxifene on portal hypertension and hepatic encephalopathy in cirrhotic rats

ABSTRACT Raloxifene, a selective estrogen receptor modulator, has been used extensively for osteoporosis. In addition to the effect of osteoporosis treatment, emerging evidences show that raloxifene affects the vascular function in different tissues. Cirrhosis is characterized with portal hypertension and complicated with hepatic encephalopathy. Portal hypertension affects portal‐systemic shunt which leads to hepatic encephalopathy that the vascular modulation might influence severity of hepatic encephalopathy. Herein, we evaluated the impact of raloxifene on bile duct ligation (BDL)‐induced cirrhotic rats. The female Sprague‐Dawley rats received BDL plus ovariectomy or sham‐operation. Four weeks later, rats were divided into 2 subgroups respectively to receive of raloxifene (10 mg/kg/day) or saline (vehicle) for 14 days. On the 43th day, motor activities and hemodynamic parameters were measured. Hepatic and vascular mRNA and protein expressions were determined. The histopathological change of liver was examined. We found that the liver biochemistry, ammonia level and motor activity were similar between cirrhotic rats with or without raloxifene administration. The hemodynamic parameters were not significantly different except that raloxifene reduced portal venous inflow. Raloxifene exacerbated hepatic fibrosis and up‐regulated hepatic endothelin‐1 and cyclooxygenase 2 protein expressions. In addition, raloxifene modulated the mRNA expressions of endothelial nitric oxide synthase, cyclooxygenase and endothelin‐1 in the superior mesenteric artery and collateral vessel. In conclusion, raloxifene aggravates hepatic fibrosis and decreases portal venous inflow in cirrhotic rats without adversely affecting portal hypertension and hepatic encephalopathy. The modulation of hepatic and vascular endothelin‐1, endothelial nitric oxide synthase and cyclooxygenase expressions may play a role in the mechanism.

2'‐hydroxyflavanone ameliorates mesenteric angiogenesis and portal‐systemic collaterals in rats with liver fibrosis

Portal‐systemic collaterals lead to dreadful consequences in patients with cirrhosis. Angiogenesis participates in the development of liver fibrosis, hyperdynamic circulation, and portal‐systemic collaterals. 2′‐Hydroxyflavanone (2′‐HF), one of the citrus fruits flavonoids, is known to have antiangiogenesis effect without adverse response. However, the relevant effects in liver fibrosis have not been surveyed.

Extrahepatic angiogenesis hinders recovery of portal hypertension and collaterals in rats with cirrhosis resolution

Liver cirrhosis is characterized by portal hypertension. However, the alteration of portal hypertension-related derangements during cirrhosis resolution is not well known. The present study aimed to establish animal models with cirrhosis resolution and to investigate the relevant changes during this process. Male Sprague-Dawley rats were applied. In reverse thioacetamide (rTAA) model, rats were randomly allocated into four groups with control, thioacetamide (TAA) cirrhosis and rTAA groups that discontinued TAA for 4 or 8 weeks after cirrhosis induction. In reverse bile duct ligation (rBDL) model, rats received choledochoduodenal shunt surgery upon the establishment of cirrhosis and 4, 8, or 16 weeks were allowed after the surgery. At the end, portal hypertension-related parameters were evaluated. Cirrhosis resolution was observed in rTAA groups. Portal pressure (PP) decreased after cirrhosis resolution but remained higher than control group (control, TAA, rTAA4, rTAA8 (mmHg): 5.4 ± 0.3, 12.9 ± 0.3, 8.6 ± 0.4, 7.6 ± 0.6). Further survey found the increased splanchnic blood flow did not reduce during cirrhosis resolution. The extrahepatic pathological angiogenesis was not ameliorated (% of mesenteric window area: 1.2 ± 0.3, 7.3 ± 1.1, 8.3 ± 1.0, 11.3 ± 2.7). In collateral system, the shunting degree reduced while the vessels structure remained. The vascular contractility of all systems and nitric oxide (NO) production were normalized. In rBDL series, PP decreased in rBDL16 groups but the extrahepatic angiogenesis persisted. In conclusion, cirrhosis resolution attenuates but not completely normalizes portal hypertension because of persistently high splanchnic inflow and angiogenesis. In clinical setting, vascular complications such as varices could persist after cirrhosis resolution and further investigation to define the follow-up and treatment strategies is anticipated.

Metformin reduces intrahepatic fibrosis and intrapulmonary shunts in biliary cirrhotic rats

Background Liver fibrosis causes portal hypertension which dilates collateral vasculature and enhances extra‐hepatic angiogenesis including intrapulmonary shunts, which subsequently complicates with hepatopulmonary syndrome. Metformin is an anti‐diabetic agent which possesses anti‐inflammation and anti‐angiogenesis properties. This study evaluated the effect of metformin treatment on liver and lung in a non‐diabetic rat model with biliary cirrhosis induced via common bile duct ligation (CBDL). Methods CBDL rats were fed with metformin 150 mg/kg/day during the 8th–28th day post operation. The hemodynamic and biochemistry parameters were tested, and blood gas analysis was performed. The liver and lung were dissected for protein analysis and immuno‐histochemical stains. Intrapulmonary shunting degree was determined using color microsphere method. Results Metformin treatment neither induced obvious hypoglycemic event nor altered hemodynamics in cirrhotic rats. The plasma levels of alanine aminotransferase were significantly reduced by metformin (control vs. metformin: 269 ± 56 vs. 199 ± 21 IU/L, P = 0.02). Sirius Red stains and CD‐68 stains showed that metformin reduced intrahepatic fibrosis and CD‐68‐positive macrophages. Metformin did not influence hypoxia and intrapulmonary angiogenesis; however, it significantly reduced intrapulmonary shunts (31.7 ± 10.1 vs. 15.0 ± 6.6%, P = 0.006.). Furthermore, metformin reduced the protein expressions of COX‐2 and PI3K in liver and COX‐1 in lung. Conclusion Metformin reduced liver injury and improved hepatic fibrosis in cirrhotic rats. It also attenuated the intrapulmonary shunts. However, the effects of metformin on pulmonary angiogenesis and hypoxia were insignificant.

The beneficial effects of curcumin in cirrhotic rats with portal hypertension

In liver cirrhosis with portal hypertension, the uneven distribution of vasoactive substances leads to increased intrahepatic vascular resistance and splanchnic vasodilatation. Angiogenesis also induces increased portal inflow and portosystemic collaterals. The collaterals may induce lethal complications such as gastroesophageal variceal hemorrhage, but the therapeutic effect of vasoconstrictors is still suboptimal due to poor collateral vasoresponsivenss. Curcumin has aroused much attention for its antifibrosis, vasoactive, and anti-angiogenesis actions. However, whether it affects the aforementioned aspects is unknown. Liver cirrhosis was induced by common bile duct ligation (CBDL) in Sprague–Dawley rats. Sham-operated rats were controls. CBDL and sham rats were randomly allocated to receive curcumin (600 mg/kg per day) or vehicle since the 15th day after BDL. On the 29th day, portal hypertension related parameters were surveyed. Portosystemic collateral in situ perfusion was performed to evaluate vascular activity. Chronic curcumin treatment decreased portal pressure (PP), cardiac index (CI) and increased systemic vascular resistance (SVR) in cirrhotic rats. In splanchnic system, curcumin decreased superior mesenteric artery (SMA) flow and increased SMA resistance. Mesenteric angiogenesis was attenuated by curcumin. Acute administration of curcumin significantly induced splanchnic vasoconstriction. The mesenteric protein expressions of p-endothelial nitric oxide synthase (eNOS), cyclooxygenase (COX) 2 (COX2), vascular endothelial growth factor (VEGF), p-VEGF receptor 2 (VEGFR2), and p-Erk were down-regulated. In collateral system, curcumin decreased portosystemic shunting and induced vasoconstriction. In conclusion, chronic curcumin administration in cirrhotic rats ameliorated portal hypertension related hemodynamic derangements and portosystemic collaterals. Curcumin also attenuated splanchnic hyperdynamic circulation by inducing vasoconstriction through inhibition of eNOS activation and by decreasing mesenteric angiogenesis via VEGF pathway blockade.

The Impact of Spironolactone on the Severity of Portal-Systemic Collaterals and Hepatic Encephalopathy in Cirrhotic Rats.

Liver cirrhosis and portal hypertension are accompanied by portal-systemic collaterals formation and lethal complications. Angiogenesis participates in the development of collaterals. Spironolactone is an aldosterone receptor antagonist used to control fluid overload in cirrhotic patients although recent studies suggest that it also inhibits angiogenesis. This study investigated the effect of spironolactone on abnormal angiogenesis and portal-systemic collaterals in cirrhosis. Liver cirrhosis was induced in Sprague-Dawley rats by common bile duct ligation (BDL), and sham-operated rats were the controls. The BDL and sham rats received spironolactone (20 mg/kg/d, oral gavage) or vehicle from day 15 to 28 after the operations. Spironolactone did not influence the portal and systemic hemodynamic, and the renal and hepatic biochemistry data, but it significantly ameliorated hepatic fibrosis, portal-systemic shunting, and mesenteric angiogenesis. Plasma vascular endothelial growth factor (VEGF) levels and the mesenteric protein expression of VEGF and phosphor-vascular endothelial growth factor receptor 2 (VEGFR-2) decreased in the spironolactone group. Spironolactone did not affect motor activity or plasma ammonia levels. The down-regulation of VEGF pathway participates, albeit partly, in the antiangiogenic effect of spironolactone. Thus, spironolactone treatment in patients with liver cirrhosis may provide additional benefits aside from ascites control.