Fructooligosaccharides reverses hepatic vascular dysfunction and dysbiosis in rats with liver cirrhosis and portal hypertension.

BACKGROUND: Portal hypertension leads to lethal complications in liver cirrhosis. Oxidative stress induced hepatic vascular dysfunction, which exaggerated vasoconstriction and increases hepatic vascular resistance (HVR). Gut dysbiosis further exacerbates portal hypertension. Fructooligosaccharides are prebiotics with potent antioxidant effect. This study aimed to evaluate the roles of fructooligosaccharides in portal hypertension-related vascular dysregulation and gut microbiome. METHODS: Sprague-Dawley rats received bile duct ligation to induce cirrhosis or sham operation as controls. The rats then randomly received fructooligosaccharides or vehicle for 4 weeks. Experiments were performed on the 29th day after operations. RESULTS: Fructooligosaccharides did not affect portal pressure. Interestingly, fructooligosaccharides significantly attenuated HVR (p = .03). Malondialdehyde, an oxidative stress marker, reduced significantly in the liver in fructooligosaccharides-treated group. In addition, superoxide dismutase and trolox equivalent antioxidant capacity increased in the treatment group. On the other hand, vasodilatation-related protein expressions, GTPCH and phospho-eNOS, enhanced significantly. Fructooligosaccharides had no adverse vasodilatation effects on splanchnic vascular system or porto-systemic collateral systems. Locomotor function was not affected by fructooligosaccharides. Faecal microbiota analysis showed that Negativicutes, Selenomonadales and Lactobacillus salivarius reduced in the fructooligosaccharides-treated group. CONCLUSION: In conclusion, fructooligosaccharides attenuate hepatic vascular dysfunction in cirrhotic rats via at least partly, ameliorate of dysbiosis and oxidative stress.

Sodium-Glucose Cotransporter-2 Inhibition Exacerbates Hepatic Encephalopathy in Biliary Cirrhotic Rats.

In liver cirrhosis, hepatic inflammation and abundant portal-systemic collaterals are indicated for the development of hepatic encephalopathy. Sodium-glucose cotransporter-2 (SGLT-2) inhibitors are a type of anti-diabetic agent which exert pleiotropic and anti-inflammatory effects. Diabetes and chronic liver disease often coexist, but the influence of SGLT-2 inhibition on liver cirrhosis and hepatic encephalopathy remains unknown. This study investigated the effect of SGLT-2 inhibition on cirrhotic rats. Biliary cirrhosis was induced in Sprague-Dawley rats via common bile duct ligation. A total of two weeks of treatment with the SGLT-2 inhibitor, empagliflozin 30 mg/kg/d, was applied. The motor activities, hemodynamics, biochemistry parameters, plasma levels of vascular endothelial growth factor (VEGF), and the severity of portal-systemic collateral shunts were measured. The hepatic histopathology and protein expressions were examined. We found that empagliflozin treatment did not affect hemodynamics, liver biochemistry, or blood glucose levels in cirrhotic rats. Empagliflozin did not affect hepatic inflammation and fibrosis. The protein expression of factors related to liver injury were not influenced by empagliflozin. However, empagliflozin decreased motor activities in cirrhotic rats and increased portal-systemic collateral shunts and VEGF plasma levels. In summary, SGLT-2 inhibition by empagliflozin did not ameliorate portal hypertension and hepatic inflammation in cirrhotic rats. In contrast, it exacerbated hepatic encephalopathy, which was evidenced by a decrease in motor activity. A possible mechanism could be an increase of portal-systemic shunts related to VEGF upregulation. Therefore, empagliflozin use should be cautious in cirrhotic patients regarding the development of hepatic encephalopathy. SIGNIFICANCE STATEMENT: Sodium-glucose cotransporter-2 inhibition by empagliflozin did not ameliorate portal hypertension and hepatic inflammation in cirrhotic rats. In contrast, it exacerbated hepatic encephalopathy through increased portal-systemic shunts related to VEGF up-regulation.

α-Adrenergic blockade prevented environmental temperature reduction-induced transient portal pressure surge in cirrhotic and portal hypertensive rats.

Exposure to low temperatures has been associated with increased gastroesophageal variceal bleeding in patients with cirrhosis and portal hypertension; however, the mechanism remains unclear. Therefore, the aim of the present study was to evaluate the impact of environmental temperature reduction on portal hypertension and the role of adrenergic signaling pathways in this phenomenon. Male Sprague-Dawley rats underwent common bile duct ligation or partial portal vein ligation to induce liver cirrhosis and/or portal hypertension. The impacts of acute or chronic changes in environmental temperature were surveyed. The results showed that acute cooling from 25 to 15°C and 5°C increased the portal pressure by 10.6% and 15.5% in cirrhotic rats, and by 22.2% and 36.1% in portal hypertensive rats, respectively. The transient portal pressure surge started shortly after cooling, reached a peak within 5 min and returned to baseline after 10 min. Systemic vascular resistance, mean arterial pressure and splanchnic blood flow increased significantly at the same time. Plasma epinephrine and norepinephrine concentrations, phospholipase C, protein kinase C activity and myosin phosphorylation of peripheral arteries increased significantly in response to cooling. Phentolamine (an α-blocker) but not propranolol (a non-selective ß-blocker) dose-dependently inhibited the transient portal pressure surge and aforementioned molecular changes. In conclusion, environmental temperature reduction induced peripheral vasoconstriction via α-adrenergic pathways, and redistribution of blood flow to the splanchnic system led to a surge in transient portal pressure. Treatment with α-adrenergic receptor antagonists may exert additional benefits in controlling portal hypertension, especially on exposure to low temperatures.

Longitudinal assessment of milestone development among internal medicine residents in Taiwan.

BACKGROUND/PURPOSE: The Accreditation Council for Graduate Medical Education (ACGME) milestones have been implemented in residency training worldwide. We investigated the development of individual competency in first-year residents (R1) and second-year postgraduate students (PGY2) who received internal medicine training in Taiwan. METHODS: A multicenter observational cohort study was conducted to evaluate the competency-based milestone evaluation designed by the Taiwan Society of Internal Medicine in 2019. The evaluation was based on the ACGME-accredited milestone ratings. Periodic evaluation of milestone achievements of R1 and PGY2, who entered the internal medicine residency training at six medical centers, was performed. Each resident was evaluated every 3 months. RESULTS: Among the 98 R1 enrolled in 2019, substantial improvement in sub-competencies, including skill in performing procedures (Patient Care 4), clinical knowledge (Medical Knowledge 1), knowledge of diagnostic testing and procedures (Medical Knowledge 2), and identify impact the cost of health care and practices cost-effective care (Systems Based Practice 3) during the two years of training. Among the 107 R1 and 46 PGY2 enrolled in 2020, no significant difference in baseline milestone ratings was observed. However, the milestone assessments of R1 in 2020 showed improvement in nearly all sub-competencies compared with the stationary status of PGY2 in 2020. CONCLUSION: We demonstrate the application of ACGME-based accredited milestone ratings to target the educational goals of internal medicine residency training in Taiwan. Differences in milestone ratings between different PGY training systems exist. The long-term impact of performance among different PGY training systems requires further investigation.

Effects of PCSK-9 Inhibition by Alirocumab Treatments on Biliary Cirrhotic Rats.

Hyperlipidemia and oxidative stress with elevated oxidized low-density lipoprotein (ox-LDL) exacerbate hepatic inflammation and fibrosis. The plasma level of low-density lipoprotein (LDL) is controlled by proprotein convertase subtilisin/kexin 9 (PCSK9). Alirocumab is a monoclonal antibody that decreases LDL via inhibiting PCSK9 function. Apart from lipid-lowering effects, alirocumab exerts anti-inflammation, anti-angiogenesis and anti-oxidant effects. This study aims to investigate the impact of alirocumab treatment on common bile duct ligation (BDL)-induced biliary cirrhotic rats. After a 4-week treatment of alirocumab, the hemodynamic data, blood biochemistry, ox-LDL level, oxidative stress markers, severity of hepatic encephalopathy and abnormal angiogenesis of BDL rats were measured and compared to the control group. BDL rats presented cirrhotic pictures and elevated ammonia, total cholesterol, LDL and ox-LDL levels compared to the control group. Alirocumab decreased plasma levels of total cholesterol, LDL, and oxidative stress markers; however, it did not affect the hemodynamics, liver and renal biochemistry, and the plasma levels of ammonia and ox-LDL. The motor activities, portal-systemic collaterals and mesenteric vascular density were not significantly different between alirocumab-treated and control groups. In addition, it did not affect hepatic inflammation, intrahepatic angiogenesis, liver fibrosis and free cholesterol accumulation in the liver of BDL rats. In conclusion, PCSK9 inhibition by alirocumab treatment ameliorates hyperlipidemia and systemic oxidative stress in biliary cirrhotic rats. However, it does not affect the plasma level of ox-LDL, intrahepatic inflammation and fibrosis. In addition, PCSK9 inhibition has a neutral effect on abnormal angiogenesis and hepatic encephalopathy in biliary cirrhotic rats.

Matrix metalloproteinase-9 inhibition or deletion attenuates portal hypertension in rodents.

Liver cirrhosis and portal hypertension are accompanied by hyperdynamic circulation, angiogenesis and portosystemic collaterals. Matrix metalloproteinases (MMPs) participate in fibrogenesis and angiogenesis, however, whether they can be targeted in cirrhosis treatment is unclear. Therefore, we performed three series of experiments to investigate this issue. Liver cirrhosis was induced by common bile duct ligation (BDL) in Sprague-Dawley rats. Sham-operated rats served as controls. Rats were randomly allocated to receive vehicle, minocycline (a nonselective MMP inhibitor) or SB-3CT (MMP-2 and -9 inhibitor) for 28 days in the first and second series, respectively. MMP-9 knockout mice were used in the third series. The results showed that minocycline ameliorated portal hypertension, hemodynamic abnormalities, reduced collateral shunting, mesenteric vascular density, plasma VEGF level and alleviated liver fibrosis. SB-3CT attenuated portal hypertension, hemodynamic derangements, reduced shunting, mesenteric vascular density, mesenteric VEGF protein expression, and liver fibrosis. Knockout BDL mice had significantly alleviated portal hypertension, liver fibrosis, liver α-SMA and mesenteric eNOS protein expressions compared to wild-type BDL mice. Liver SMAD2 phosphorylation was down-regulated in all series with MMP inhibition or knock-out. In conclusion, MMP-9 inhibition or deletion ameliorated the severity of cirrhosis, portal hypertension, and associated derangements. MMP-9 may be targeted in the treatment of liver cirrhosis.

Glycyrrhizin Attenuates Portal Hypertension and Collateral Shunting via Inhibition of Extrahepatic Angiogenesis in Cirrhotic Rats.

Portal hypertension develops along with liver cirrhosis then induces the formation of portal-systemic collaterals and lethal complications. Extrahepatic angiogenesis plays an important role. Glycyrrhizin has been found to exhibit anti-angiogenic features, which leads to its extensive use. However, the relevant effects of glycyrrhizin on liver cirrhosis and portal hypertension have not been evaluated. This study thus aimed to investigate the impact of glycyrrhizin on portal hypertension-related derangements in cirrhotic rats. Male Sprague-Dawley rats received bile duct ligation (BDL) to induce cirrhosis or sham operation as control. The rats were subdivided to receive glycyrrhizin (150 mg/kg/day, oral gavage) or vehicle beginning on the 15th day post operation, when BDL-induced liver fibrosis developed. The effects of glycyrrhizin were determined on the 28th day, the typical timing of BDL-induced cirrhosis. Glycyrrhizin significantly reduced portal pressure (p = 0.004). The splanchnic inflow as measured by superior mesenteric arterial flow decreased by 22% (p = 0.029). The portal-systemic collateral shunting degree reduced by 30% (p = 0.024). The mesenteric angiogenesis and phospho-VEGFR2 protein expression were also downregulated (p = 0.038 and 0.031, respectively). Glycyrrhizin did not significantly influence the liver biochemistry data. Although glycyrrhizin tended to reverse liver fibrosis, statistical significance was not reached (p = 0.069). Consistently, hepatic inflow from portal side, hepatic vascular resistance, and liver fibrosis-related protein expressions were not affected. Glycyrrhizin treatment at the stage of hepatic fibrosis still effectively attenuated portal hypertension and portosystemic collateral shunting. These beneficial effects were attributed to, at least in part, the suppression of mesenteric angiogenesis by VEGF signaling pathway downregulation.

Sustained effects of faculty leadership development modules for clinical instructors of core competences education in Taiwan: a four-year explanatory case study.

BACKGROUND: The Accreditation Council for Graduate Medical Education (ACGME) core competencies (CC) in general medicine-based primary care are essential for junior medical trainees. In this country, a regular faculty development (FD) program aimed at training faculty in instructing (teaching and assessing) these CC had operated. However, leadership was not emphasized. In a new intervention module, the roles and associated responsibilities of clinical instructors to conduct, design, and lead CC-based education were emphasis. AIMS: This follow-up explanatory case study compares the effectiveness of intervention module with that of the previous regular module. METHODS: The regular group (n = 28) comprised clinical instructors who participated in the FD module during the 2013-2014 year while the intervention group (n = 28) was composed of 2015-2016 participants. Prior to the formal (hands-on) training, participants in the intervention group were asked to study the online materials of the regular module. These participants then received a 30-h hands-on training in conducting, designing, and leading skills. Finally, they prepared a 10-h reflective end-of-module presentation of their real-world practices. RESULTS: Following the training, a higher degree improvement in participants self-reported familiarity with CC education, self-confidence in their ability to deliver CC education and sustained involve CC education were noted among the intervention FD group, compared with the regular FD group. In the intervention group, senior academicians (associate and full professor) are more substantially involved in designing and leading CC-based courses than junior academicians (lecturers and assistant professors). Among non-teaching award winners of in the intervention FD group, the follow-up degree of sustained involvement in delivering, designing and leading CC-based courses was significantly higher than that of the regular group. CONCLUSIONS: Our study demonstrated that leadership training in the intervention FD modules substantially motivated clinical instructors to become leaders in CC education.

Effects of Caffeine Treatment on Hepatopulmonary Syndrome in Biliary Cirrhotic Rats.

Hepatopulmonary syndrome (HPS) is a lethal complication of cirrhosis characterized by hypoxia and overt intrapulmonary shunting. In this study, we investigated the effect of caffeine in rats with common bile duct ligation (CBDL)-induced liver cirrhosis and HPS. CBDL rats were randomly allocated to receive caffeine or vehicle for 14 days. On the 28th day after CBDL, mortality rate, hemodynamics, liver, and renal biochemistry parameters and arterial blood gas analysis were evaluated. Lung and liver were dissected for the evaluation of inflammation, angiogenesis and protein expressions. In another series with parallel groups, the intrapulmonary shunting was determined. Caffeine significantly reduced portal pressure (caffeine vs. control: 10.0 ± 3.7 vs. 17.0 ± 8.1 mmHg, p < 0.05) in CBDL rats. The mortality rate, mean arterial pressure, biochemistry data and hypoxia were similar between caffeine-treated and control groups. Caffeine alleviated liver fibrosis and intrahepatic angiogenesis but intrapulmonary inflammation and angiogenesis were not ameliorated. The hepatic VEGF/Rho-A protein expressions were down-regulated but the pulmonary inflammation- and angiogenesis-related protein expressions were not significantly altered by caffeine. Caffeine did not reduce the intrapulmonary shunting, either. Caffeine has been shown to significantly improve liver fibrosis, intrahepatic angiogenesis and portal hypertension in cirrhotic rats, however, it does not ameliorate HPS.

Endotoxemia-enhanced renal vascular reactivity to endothelin-1 in cirrhotic rats.

Hepatorenal syndrome (HRS), a severe complication of advanced cirrhosis, is defined as hypoperfusion of kidneys resulting from intense renal vasoconstriction in response to generalized systemic arterial vasodilatation. Nevertheless, the mechanisms have been barely investigated. Cumulative studies demonstrated renal vasodilatation in portal hypertensive and compensated cirrhotic rats. Previously, we identified that blunted renal vascular reactivity of portal hypertensive rats was reversed after lipopolysaccharide (LPS). This study was therefore conducted to delineate the sequence of renal vascular alternation and underlying mechanisms in LPS-treated cirrhotic rats. Sprague-Dawley rats were randomly allocated to receive sham surgery (Sham) or common bile duct ligation (CBDL). LPS was induced on the 28th day after surgery. Kidney perfusion was performed at 0.5 or 3 h after LPS to evaluate renal vascular response to endothelin-1 (ET-1). Endotoxemia increased serum ET-1 levels ( P < 0.0001) and renal arterial blood flow ( P < 0.05) in both Sham and CBDL rats. CBDL rats showed enhanced renal vascular reactivity to ET-1 at 3 h after LPS ( P = 0.026). Pretreatment with endothelin receptor type A (ETA) antagonist abrogated the LPS-enhanced renal vascular response in CBDL rats ( P < 0.001). There were significantly lower inducible nitric oxide synthase (iNOS) expression but higher ETA and phosphorylated extracellular signal-regulated kinase (p-ERK) expressions in renal medulla of endotoxemic CBDL rats ( P < 0.05). We concluded that LPS-induced renal iNOS inhibition, ETA upregulation, and subsequent ERK signaling activation may participate in renal vascular hyperreactivity in cirrhosis. ET-1-targeted therapy may be feasible in the control of HRS. NEW & NOTEWORTHY Hepatorenal syndrome (HRS) occurred in advanced cirrhosis after large-volume paracentesis or bacterial peritonitis. We demonstrated that intraperitoneal lipopolysaccharide (LPS) enhanced renal vascular reactivity to endothelin-1 (ET-1) in cirrhotic rats, accompanied by inducible nitric oxide synthase inhibition, endothelin receptor type A (ETA) upregulation, and subsequent extracellular signal-regulated kinase activation in renal medulla. Pretreatment with ETA antagonist abrogated the LPS-enhanced renal vascular response in common bile duct ligation rats. These findings suggest that further clinical investigation of ET-1-targeted therapy may be feasible in the control of HRS.

Nucleos(t)ide Analogs Do Not Independently Influence Hepatic Fibrosis and Portal Hypertension beyond Viral Suppression in CBDL-Induced Cirrhotic Rat.

Chronic hepatitis is the major cause of liver cirrhosis and portal hypertension. Several factors affect portal pressure, including liver fibrosis, splanchnic vasodilatation, and pathologic angiogenesis. Nucleos(t)ide analogs (NUCs), the oral antiviral agents, effectively attenuate chronic hepatitis B-related liver cirrhosis and portal hypertension via viral suppression and alleviation of hepatitis. On the other hand, NUCs affect tumor necrosis factor (TNF)-α, vascular endothelial growth factor (VEGF), and nitric oxide, which participate in fibrogenesis, vasodilatation, and angiogenesis. However, whether NUCs independently influence liver fibrosis and portal hypertension beyond viral suppression is unknown. This study thus aimed to evaluate the influences of three frequently used NUCs in rats with nonviral cirrhosis. Male Sprague-Dawley rats received common bile duct ligation (CBDL) to induce cholestatic cirrhosis and portal hypertension. The rats were randomly allocated into four groups, treated by mouth with lamivudine (30 mg/kg per day), entecavir (0.09 mg/kg per day), tenofovir (50 mg/kg per day), or distilled water (vehicle control) from the 15th day after CBDL. On the 29th day, liver cirrhosis- and portal hypertension-related parameters were evaluated. The results showed that chronic NUCs treatment did not affect hemodynamic parameters, plasma TNF-α concentration, and hepatic fibrogenesis protein expressions in rats with nonviral cirrhosis. Though the mesenteric VEGF receptor 2 phosphorylation was downregulated in NUCs-treated groups, the splanchnic angiogenesis was not influenced. In conclusion, lamivudine, entecavir, and tenofovir had no additional effects on liver cirrhosis and portal hypertension in rats with nonviral cirrhosis.

Insulin reverses major portal hypertension-related derangements in rats with liver cirrhosis and diabetes.

Liver cirrhosis is accompanied by increased intrahepatic resistance and angiogenesis-related portosystemic collaterals formation. Diabetic patients suffer from abnormal vasoresponsiveness and angiogenesis that can be ameliorated by glucose control. However, the relevant presentation is not clear in those with cirrhosis and diabetes, in whom insulin is the treatment of choice. Liver cirrhosis was induced in Sprague-Dawley rats with common bile duct ligation (BDL) and sham rats were used as controls. Streptozotocin 60 mg/kg (STZ, i.p., to induce diabetes) or vehicle was injected. The rats received BDL and STZ injections were injected with insulin or vehicle. On the 29th day after the procedure, the groups were surveyed for (1) systemic and portal hemodynamics; (2) mesenteric vascular density; (3) severity of portosystemic collaterals; (4) hepatic resistance using in situ liver perfusion; (5) histology survey of mesentery and liver; and (6) mesentery angiogenesis- and liver fibrogenesis-related protein expressions. Compared with the cirrhotic rats, the cirrhotic diabetic rats had lower body weight, cardiac output, superior mesenteric arterial (SMA) resistance and portal venous (PV) resistance, and higher SMA and PV flow, which were mostly reversed by insulin. The cirrhotic diabetic rats also had increased mesenteric vascular density, and enhanced pERK, pAkt, VEGF, VEGFR2 protein expressions that were reversed by insulin. Insulin decreased the degree of shunting in the diabetic cirrhotic rats. Hepatic perfusion pressure and severity of liver fibrosis were not significantly influenced by diabetes and insulin treatment in the cirrhotic rats. In conclusion, diabetes aggravated hemodynamic derangements, mesenteric angiogenesis and collaterals in the cirrhotic rats, which were mostly ameliorated by insulin. Further clinical investigations are warranted.

Voluntary attendance of small-group brainstorming tutoring courses intensify new clerk's "excellence in clinical care": a pilot study.

BACKGROUND: Clerkship provides a unique way of transferring the knowledge and skills gathered during medical school's curriculum into real-ward clinical care environment. The annual program evaluation has indicated that the training of clerks in diagnostic and clinical reasoning skills needed to be enhanced. Recently, "clinical excellence" program have been promoted in our institution to augment the excellence in clinical care of new clerks. Current study aims to evaluate whether this pilot program improve the "clinical excellence" of new clerks. METHODS: In a pilot study, groups of new clerks in years 2013 and 2014 voluntarily attended either a small-group brainstorming course or a didactic classroom tutoring courses as part of their 3-month internal medicine clinical rotation block. A third group of new clerks did not join either of the above courses and this group served as the control group. Pre-block/post-block self-assessment and post-block 5-station mini-Objective Subjective Clinical Examinations (OSCEs) were used to evaluate the effectiveness of these two additional courses that trained diagnostic and clinical reasoning skills. RESULTS: Overtime, the percentages of new clerks that attended voluntarily either the small-group brainstorming or classroom tutoring courses were increased. Higher post-block self-assessed diagnostic and clinical reasoning skill scores were found among individuals who attended the small-group brainstorming courses compared to either the didactic group or the control group. In a corresponding manner, the small-group brainstorming group obtained higher summary OSCEdiag and OSCEreason scores than either the didactic group or control group. For all basic images/laboratory OSCE stations, the individual diagnostic skill (OSCEdiag) scores of the small-group brainstorming group were higher than those of the didactic group. By way of contrast, only the clinical reasoning skill (OSCEreason) scores of the basic electrocardiogram and complete blood count + biochemistry OSCE station of thesmall-group brainstorming group were higher than those of the didactic group. Among the small-group brainstorming group, clerks with higher cumulative learning hours (>30-h) had significant higher OSCEdiag and OSCEreason scores (>400) than those with less cumulative learning hours. CONCLUSION: Our pilot study provides a successful example of the use of a small-group tutoring courses for augmenting the diagnostic and clinical reasoning skills of new clerks. The positive results obtained during the initial 2-year long pilot "clinical excellence" program have encouraged the formal implementation of this course as part of the clerkship curriculum.

Caffeine ameliorates hemodynamic derangements and portosystemic collaterals in cirrhotic rats.

UNLABELLED: 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.

Endothelin receptor blockers reduce shunting and angiogenesis in cirrhotic rats.

BACKGROUND: 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. DESIGN: This study aimed to survey the influences of ET-1 in cirrhosis-related angiogenesis. Common bile duct ligation was performed on Spraque-Dawley rats to induce cirrhosis. Since the 14th day after the operation, rats randomly received distilled water (DW, control), bosentan [a nonselective ET receptor (ETR) blocker] or ambrisentan (a selective ETA R blocker) for 4 weeks. On the 43rd day, portal and systemic haemodynamics, liver biochemistry, portosystemic shunting degree, mesenteric vascular density, mRNA and/or protein expressions of relevant angiogenic factors were evaluated. RESULTS: In cirrhotic rats, bosentan significantly reduced portal pressure. Ambrisentan did not influence haemodynamics and liver biochemistry. Both of them significantly improved the severity of portosystemic collaterals and decreased the mesenteric vascular density. Compared with the DW-treated cirrhotic rats, splenorenal shunt and mesenteric inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX2), vascular endothelial growth factor mRNA expressions and mesenteric iNOS, COX2, VEGF, phospho-VEGF receptor 2, Akt and phospho-Akt protein expressions were down-regulated in both groups. CONCLUSIONS: In rats with liver cirrhosis, both nonselective and selective ETA R blockade ameliorate the severity of portosystemic shunting and mesenteric angiogenesis via the down-regulation of VEGF pathway and relevant angiogenic factors. ET receptors may be targeted to control the severity of portosystemic collaterals and associated complications in cirrhosis.

Rosuvastatin improves hepatopulmonary syndrome through inhibition of inflammatory angiogenesis of lung.

The hepatopulmonary syndrome (HPS) is characterized by hypoxia and increased intrapulmonary shunts in cirrhotic patients. Emerging evidence showed promising results of treating HPS by abolishment of intrapulmonary inflammation and angiogenesis. Rosuvastatin is a kind of 3-hydroxy-methyl-3-glutamyl coenzyme A reductase inhibitor. In addition to lipid-lowering effects, it has anti-inflammation and anti-angiogenesis properties. We postulated that rosuvastatin treatment can ameliorate HPS. Common bile duct ligation (CBDL) was applied in an experimental HPS animal model. CBDL rats received 2-week rosuvastatin (20 mg/kg/day) treatments from the fifteenth day after operation. The haemodynamic data, blood gas analysis, liver biochemistries, tumour necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF) were examined after rosuvastatin treatment. The liver and lung tissues were dissected for histopathological studies and protein analyses. In the parallel groups, intrapulmonary shunts were determined. The haemodynamic and liver biochemistries were not changed after rosuvastatin treatment in CBDL rats, but the alveolar-arterial oxygen pressure gradient was significantly decreased, implying that HPS-induced hypoxia was reversed after rosuvastatin treatment. In addition, rosuvastatin treatment reduced intrapulmonary shunts and plasma levels of VEGF and TNF-α. Besides, the intrapulmonary protein expression of nuclear factor kappa B (NF-κB), VEGF receptor (VEGFR)-1,2 and Rho-associated A kinase were significantly down-regulated and the intrapulmonary angiogenesis was ameliorated. We concluded that rosuvastatin alleviates experimental HPS through blockade of pulmonary inflammatory angiogenesis via TNF-α/NF-κB and VEGF/Rho-associated A kinase pathways down-regulation.

Diabetes enhances the intrahepatic vascular response to endothelin-1 in cirrhotic rats: association with the ETA receptor and pERK up-regulation.

BACKGROUND & AIMS: Cirrhosis is characterized by increased intrahepatic vascular resistance and enhanced vasocontractile responsiveness that impedes portal inflow and elevates portal pressure, in which endothelin-1 (ET-1) plays a role. Diabetes and glucose influence vasoresponsiveness but their impact on the intrahepatic vascular bed in cirrhosis is unknown. To investigate intrahepatic ET-1 vasoresponsiveness in cirrhotic rats with and without diabetes and to explore the underlying mechanisms. METHODS: Spraque-Dawley rats received common bile-duct ligation (BDL) to induce cirrhosis. Streptozotocin was injected to induce diabetes in the BDL rats (BDL/STZ). In situ liver perfusion was performed to obtain the ET-1 concentration-response curves. The basic hemodynamics and hepatic protein expressions of ET-1 receptors, pERK, ERK, pAkt, Akt, iNOS, eNOS, peNOS and calmodulin were evaluated. The circulating concentrations of N-terminal pro-brain natriuretic peptide (NT-ProBNP), blood urea nitrogen (BUN) and creatinine were also determined. RESULTS: Body weight, mean arterial pressure, heart rate and survival rate were significantly decreased in the BDL/STZ rats. The perfusion pressure changes in response to ET-1 were higher in the BDL/STZ group for all perfusates. ETA receptor and pERK expressions were enhanced in the BDL/STZ group. The circulating concentrations of NT-ProBNP, BUN and creatinine, as well as SMA flow, were not significantly different between the BDL and BDL/STZ groups. CONCLUSION: Cirrhotic rats with diabetes showed higher intrahepatic ET-1 vasoresponsiveness than normoglycemic cirrhotic rats. This effect is not affected by changes in perfused glucose concentration and may be related, at least in part, to intrahepatic ETA R receptor and pERK over-expression.

Lipopolysaccharide enhanced renal vascular response to endothelin-1 through ETA overexpression in portal hypertensive rats.

BACKGROUND AND AIM: Hypo-perfusion resulting from intense renal vasoconstriction is traditionally contributed to renal dysfunction in advanced liver disease, although cumulative studies demonstrated renal vasodilatation with impaired vascular contractility to endogenous vasoconstrictors in portal hypertension and compensated liver cirrhosis. The pathophysiology of altered renal hemodynamics remains unclear. This study, using a rat model of portal hypertension with superimposed endotoxemia, was designed to delineate the evolution of renal vascular reactivity and vaso-regulatory gene expression during liver disease progression. METHODS: Rats were randomized into sham surgery (SHAM) or partial portal vein ligation (PVL). Endotoxemia was induced by intraperitoneal injection of lipopolysaccharide (LPS) on the seventh day following surgery. Isolated kidney perfusion was performed at 0.5 h or 5 h after LPS to evaluate renal vascular response to endothelin-1. RESULTS: In contrast to impaired vascular contractility of SHAM rats, PVL rats displayed enhanced renal vascular reactivity to endothelin-1 at 5 h following endotoxemia. There were extensive upregulations of inducible nitric oxide synthase in kidney tissues of endotoxemic rats. The changes of renal endothelin receptor type A (ETA ) level paralleled with the changes of renal vascular reactivity in LPS-treated rats. Compared with SHAM rats, PVL rats showed increased renal ETA and phosphorylated extracellular-signal-regulated kinases 1/2 (p-ERK1/2) at 5 h after LPS. CONCLUSION: LPS-induced systemic hypotension induces a paradoxical change of renal vascular response to endothelin-1 between SHAM and PVL rats. LPS-induced renal vascular hyperreactivity in PVL rats was associated with upregulation of renal ETA and subsequent activation of ERK1/2 signaling.

Ezetimibe treatment reduces oxidized low-density lipoprotein in biliary cirrhotic rats.

BACKGROUND: In liver cirrhosis, chronic inflammation is associated with an increase in oxidative stress, and subsequently an increase in the concentration of oxidized low-density lipoprotein (ox-LDL). Ezetimibe is a lipid-lowering agent with anti-inflammation and anti-oxidative stress activities. This study aimed to investigate the effect of ezetimibe treatment on ox-LDL in cirrhotic rats. METHODS: Biliary cirrhosis was induced in Sprague-Dawley rats with common bile duct ligation (BDL). Sham-operated rats served as surgical controls. Ezetimibe (10 mg/kg/d) or vehicle was administered in the sham-operated or BDL rats for 4 weeks, after which hemodynamic parameters, biochemistry data, and oxidative stress were evaluated. Plasma and intrahepatic ox-LDL levels were also examined, and hepatic proteins were analyzed to explore the mechanism of ezetimibe treatment. RESULTS: The BDL rats had typical features of cirrhosis including jaundice, impaired liver function, hyperlipidemia, and elevated ox-LDL levels compared to the sham-operated rats. Ezetimibe treatment did not affect hemodynamics, liver biochemistry, or plasma lipid levels. However, it significantly reduced oxidative stress, plasma levels of ox-LDL, and tumor necrosis factor α. In addition, ezetimibe upregulated the hepatic protein expression of an ox-LDL scavenger (lectin-like ox-LDL rececptor-1), which resulted in reductions in intrahepatic ox-LDL and fat accumulation in the BDL rats. Nevertheless, ezetimibe treatment did not ameliorate hepatic inflammation or liver fibrosis. CONCLUSION: Ezetimibe reduced plasma and intrahepatic ox-LDL levels in the cirrhotic rats. Furthermore, it ameliorated intrahepatic fat accumulation and oxidative stress. However, ezetimibe did not alleviate hepatic fibrosis or inflammation in the biliary cirrhotic rats.

Low-dose alcohol exacerbates hyperdynamic circulation and shunting in non-alcoholic cirrhotic rats.

BACKGROUND: Portal hypertension affects hepatic, splanchnic and portosystemic collateral systems. Although alcohol is a well-known risk factor for liver cirrhosis, it also affects vascular contractility. However, the relevant effects on portal hypertension have not been evaluated in non-alcoholic cirrhosis. The present study aimed to investigate the impacts of low-dose alcohol on portal hypertension-related derangements in non-alcoholic cirrhotic rats. METHODS: Sprague-Dawley rats received bile duct ligation to induce cirrhosis or sham operation as controls. The chronic or acute effects of low-dose alcohol (2.4 g/kg/day, oral gavage, approximately 1.3 drinks/day in humans) were evaluated. RESULTS: The chronic administration of low-dose alcohol did not precipitate liver fibrosis in the sham or cirrhotic rats; however, it significantly increased splanchnic blood inflow (P=0.034) and portosystemic collaterals (P=0.001). Mesenteric angiogenesis and pro-angiogenic proteins were up-regulated in the alcohol-treated cirrhotic rats, and poorer collateral vasoresponsiveness to vasoconstrictors (P<0.001) was noted. Consistently, acute alcohol administration reduced splenorenal shunt resistance. Collateral vasoresponsiveness to vasoconstrictors also significantly decreased (P=0.003). CONCLUSIONS: In non-alcoholic cirrhosis rats, a single dose of alcohol adversely affected portosystemic collateral vessels due to vasodilatation. Long-term alcohol use precipitated splanchnic hyperdynamic circulation, in which mesenteric angiogenesis played a role. Further studies are warranted to evaluate the benefits of avoiding low-dose alcohol consumption in patients with non-alcoholic cirrhosis.