Pharmacologic Management of Portal Hypertension

Targeting 5-Hydroxytryptamine Receptor 1A in the Portal Vein to Decrease Portal Hypertension

BACKGROUNDS & AIMS

Portal hypertension (PH) is one of the most frequent complications of chronic liver disease. The peripheral 5-hydroxytryptamine (5-HT) level was increased in cirrhotic patients. We aimed to elucidate the function and mechanism of 5-HT receptor 1A (HTR1A) in the portal vein (PV) on PH.

METHODS

PH models were induced by thioacetamide injection, bile duct ligation, or partial PV ligation. HTR1A expression was detected using real-time polymerase chain reaction, in situ hybridization, and immunofluorescence staining. In situ intraportal infusion was used to assess the effects of 5-HT, the HTR1A agonist 8-OH-DPAT, and the HTR1A antagonist WAY-100635 on portal pressure (PP). Htr1a-knockout (Htr1a-/-) rats and vascular smooth muscle cell (VSMC)-specific Htr1a-knockout (Htr1aΔVSMC) mice were used to confirm the regulatory role of HTR1A on PP.

RESULTS

HTR1A expression was significantly increased in the hypertensive PV of PH model rats and cirrhotic patients. Additionally, 8-OH-DPAT increased, but WAY-100635 decreased, the PP in rats without affecting liver fibrosis and systemic hemodynamics. Furthermore, 5-HT or 8-OH-DPAT directly induced the contraction of isolated PVs. Genetic deletion of Htr1a in rats and VSMC-specific Htr1a knockout in mice prevented the development of PH. Moreover, 5-HT triggered adenosine 3',5'-cyclic monophosphate pathway-mediated PV smooth muscle cell contraction via HTR1A in the PV. We also confirmed alverine as an HTR1A antagonist and demonstrated its capacity to decrease PP in rats with thioacetamide-, bile duct ligation-, and partial PV ligation-induced PH.

CONCLUSIONS

Our findings reveal that 5-HT promotes PH by inducing the contraction of the PV and identify HTR1A as a promising therapeutic target for attenuating PH. As an HTR1A antagonist, alverine is expected to become a candidate for clinical PH treatment.

Pharmacotherapies for Portal Hypertension: Current Status and Expanding Indications

Purpose

Non-selective beta blockers remain pharmacotherapy of choice for prevention of first episode of variceal bleeding (primary prevention) and for prevention of its recurrence after initial hemostasis (secondary prophylaxis). This review will update the current and emerging pharmacological therapies for portal hypertension.

Recent findings

Data have emerged on carvedilol in preventing hepatic decompensation and improving patient survival among patients with clinically significant portal hypertension. Because measurement of WHVP is invasive and not feasible in routine practice, non-invasive tests with liver stiffness measurement in combination with platelet count may be accurate in identifying clinically significant portal hypertension.

Summary

Carvedilol is more effective in reducing portal pressure compared to nadolol or propranolol. Its use has expanded to reduce risk of hepatic decompensation among patients with CSPH, which can be identified non-invasively using liver stiffness and platelet count. Studies are needed on non-invasive biomarkers to guide and optimize pharmacological treatment of portal hypertension.

Emerging Therapeutic Targets for Portal Hypertension

Purpose of Review

Portal hypertension is responsible of the main complications of cirrhosis, which carries a high mortality. Recent treatments have improved prognosis, but this is still far from ideal. This paper reviews new potential therapeutic targets unveiled by advances of key pathophysiologic processes.

Recent Findings

Recent research highlighted the importance of suppressing etiologic factors and a safe lifestyle and outlined new mechanisms modulating portal pressure. These include intrahepatic abnormalities linked to inflammation, fibrogenesis, vascular occlusion, parenchymal extinction, and angiogenesis; impaired regeneration; increased hepatic vascular tone due to sinusoidal endothelial dysfunction with insufficient NO availability; and paracrine liver cell crosstalk. Moreover, pathways such as the gut-liver axis modulate splanchnic vasodilatation and systemic inflammation, exacerbate liver fibrosis, and are being targeted by therapy. We have summarized studies of new agents addressing these targets.

Summary

New agents, alone or in combination, allow acting in complementary mechanisms offering a more profound effect on portal hypertension while simultaneously limiting disease progression and favoring regression of fibrosis and of cirrhosis. Major changes in treatment paradigms are anticipated.

Successful Percutaneous Transhepatic Obliteration Plus Sengstaken-Blakemore Tube Combination Therapy for Recurrent Gastroesophageal Variceal Bleeding: A Case Report

We treated a case of gastroesophageal varices due to decompensated liver cirrhosis associated with Wilson's disease. The varicose veins penetrated the paraesophageal vein. We performed endoscopic variceal ligation (EVL) on the perforating vein and endoscopic injection sclerotherapy (EIS) distally. However, 5 days after treatment, the patient vomited blood. Esophagogastroduodenoscopy showed bleeding from the ulcer after EVL at the perforating vein. We performed EVL and stopped the bleeding. However, the next day, she vomited blood again and developed hemorrhagic shock. We were able to achieve hemostasis and save the patient's life with combination therapy consisting of percutaneous transhepatic obliteration and Sengstaken-Blakemore tube placement.

Efficacy of Endoscopic Intervention plus Growth Inhibitor and Patient Self-Management in the Treatment of Esophagogastric Variceal Bleeding in Cirrhosis

Objective

To assess the efficacy of endoscopic intervention plus growth inhibitor and patient self-management in the treatment of esophagogastric variceal bleeding.

Methods

Between January 2019 and December 2021, 60 patients with esophagogastric variceal bleeding treated in our hospital were assessed for eligibility and randomly recruited. They were concurrently and randomly assigned at a ratio of 1 : 1 to receive either endoscopic intervention plus growth inhibitor (control group) or endoscopic intervention plus growth inhibitor and patient self-management (observation group). The endpoint is clinical efficacy.

Results

All eligible patients showed a similar time of hemostasis, success rate of hemostasis, rebleeding rate, and disappearance rate of varicose veins (P > 0.05). Endoscopic intervention plus growth inhibitor and patient self-management were associated with a lower incidence of complication (6.67%, including 1 (3.34%) case of ulcer and 1 (3.34%) case of fever) than endoscopic intervention plus growth inhibitor (26.67%, including 3 (10.00%) cases of ulcer, 2 (6.67%) cases of retrosternal pain, and 3 (10.00%) cases of fever) (P < 0.05). Patients in the observation group had significantly higher life satisfaction scores (25.17 ± 4.28 and 23.68 ± 5.17) than those in the control group (22.13 ± 2.24 and 18.12 ± 3.28) (P < 0.05). A decrease in life satisfaction scores was observed at 6 months after treatment, and the patients given patient self-management showed a higher satisfaction (P < 0.05).

Conclusion

Endoscopic intervention plus growth inhibitor and patient self-management yielded remarkable clinical efficacy in the treatment of esophagogastric variceal bleeding as it reduces the incidence of complication and enhances the life satisfaction of patients, and so it is worthy of clinical promotion.

Diammonium glycyrrhizinate ameliorates portal hypertension by regulating portal macrophage oxidation and superoxide dismutase 3

Portal hypertension (PHT) is a complication of liver diseases. Increased intrahepatic vascular resistance is attributed to reduced bioavailability of vasodilator substances. The macrophage activation and superoxide dismutase 3 (SOD3) involve in the pathogenesis of PHT. Diammonium glycyrrhizinate (DG) is the salt form of glycyrrhizin derived from Radix glycyrrhizae, exerting anti-oxidant activities and be beneficial for liver injury. Here, we aimed to investigate effects of DG on PHT and explore its underlying mechanisms on regulation of macrophages and SOD3. The carbon tetrachloride induced PHT rats received administration of liposome-encapsulated clodronate for hepatic macrophage depletion, or PBS liposomes for matched control. DG (25 mg/kg) or vehicle was gavaged. Portal pressure in vivo, and serum biomarkers of macrophage activation were measured. The nitric oxide (NO) and prostacyclin (PGI₂) bioavailability was evaluated in the isolated portal perfused rat livers. Liver tissues were collected to evaluate cirrhosis, macrophage oxidation, and SOD3 activity. Depletion of hepatic macrophages decreased portal pressure, increased bioavailability of NO and PGI₂, and restored SOD3 activity. DG effectively decreased portal pressure, relieved cirrhosis, inhibited macrophage activation. DG increased bioavailability of NO and PGI₂ to relax portal veins. DG relieved portal macrophage oxidation through decreasing nicotinamide adenine dinucleotide phosphate oxidase 2 and inducible NO synthase expressions, elevated SOD3 activities and increased SOD3 expressions at portal triads. These findings indicated that DG restored SOD3 activity, against portal macrophage oxidation, protected bioavailability of NO and PGI₂, thereby reduced portal pressure. It suggested a potential use of DG for PHT treatment.

Quantitative analysis of in-TIPS thrombosis in abdominal CT

Purpose

To identify transjugular intrahepatic portosystemic shunt (TIPS) thrombosis in abdominal CT scans applying quantitative image analysis.

Materials and methods

We retrospectively screened 184 patients to include 20 patients (male, 8; female, 12; mean age, 60.7 ± 8.87 years) with (case, n = 10) and without (control, n = 10) in-TIPS thrombosis who underwent clinically indicated contrast-enhanced and unenhanced abdominal CT followed by conventional TIPS-angiography between 08/2014 and 06/2020. First, images were scored visually. Second, region of interest (ROI) based quantitative measurements of CT attenuation were performed in the inferior vena cava (IVC), portal vein and in four TIPS locations. Minimum, maximum and average Hounsfield unit (HU) values were used as absolute and relative quantitative features. We analyzed the features with univariate testing.

Results

Subjective scores identified in-TIPS thrombosis in contrast-enhanced scans with an accuracy of 0.667 – 0.833. Patients with in-TIPS thrombosis had significantly lower average (p < 0.001), minimum (p < 0.001) and maximum HU (p = 0.043) in contrast-enhanced images. The in-TIPS / IVC ratio in contrast-enhanced images was significantly lower in patients with in-TIPS thrombosis (p < 0.001). No significant differences were found for unenhanced images. Analyzing the visually most suspicious ROI with consecutive calculation of its ratio to the IVC, all patients with a ratio < 1 suffered from in-TIPS thrombosis (p < 0.001, sensitivity and specificity = 100%).

Conclusion

Quantitative analysis of abdominal CT scans facilitates the stratification of in-TIPS thrombosis. In contrast-enhanced scans, an in-TIPS / IVC ratio < 1 could non-invasively stratify all patients with in-TIPS thrombosis.

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Quantitative image analyses of CT scans allow the diagnosis of in-TIPS thrombosis.

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Negative quantitative image analysis may reduce the necessity of an angiography.

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Unenhanced CT scans have no additional benefit for diagnosis of in-TIPS thrombosis.

Self-expandable metallic stents (SEMS) in esophageal varices post-band ulcer refractory bleeding: a retrospective study

Background

Post-variceal band ligation bleeding ulcer is a severe complication with considerable mortality. We tried evaluating self-expandable metallic stent (SEMS) with concern to the ulcer morphology not well studied.

Results

We did a retrospective analysis of patients with bleeding post-band ulcers and treated by SEMS with concern to control bleeding and 6 weeks survival. Twenty-eight patients studied had their age (mean ± S.D.) 57.8 ± 8.6 years, and 85.7% were males. The Child-Pugh score range was 5–12]. Control of bleeding by SEMS was achieved in 23 (82.1%) patients, and overall, 6-week survival was 75%. Both post-band ulcer types B (oozing blood and type C (active spurted) were a risk for 6 weeks mortality (P = 0.04, OR 1.58, CI 95% 1.12–2.23).

Conclusion

SEMS is considered an excellent choice to control esophageal post-banding ulcer bleeding and a definite treatment bridge.

Celecoxib reduces hepatic vascular resistance in portal hypertension by amelioration of endothelial oxidative stress

The balance between endothelial nitric oxide (NO) synthase (eNOS) activation and production of reactive oxygen species (ROS) is very important for NO homeostasis in liver sinusoidal endothelial cells (LSECs). Overexpression of cyclooxygenase‐2 (COX‐2), a major intravascular source of ROS production, has been observed in LSECs of cirrhotic liver. However, the links between low NO bioavailability and COX‐2 overexpression in LSECs are unknown. This study has confirmed the link between low NO bioavailability and COX‐2 overexpression by COX‐2‐dependent PGE2‐EP2‐ERK1/2‐NOX1/NOX4 signalling pathway in LSECs in vivo and in vitro. In addition, the regulation of COX‐2‐independent LKB1‐AMPK‐NRF2‐HO‐1 signalling pathway on NO homeostasis in LSECs was also elucidated. The combinative effects of celecoxib on diminishment of ROS via COX‐2‐dependent and COX‐2‐independent signalling pathways greatly decreased NO scavenging. As a result, LSECs capillarisation was reduced, and endothelial dysfunction was corrected. Furthermore, portal hypertension of cirrhotic liver was ameliorated with substantial decreasing hepatic vascular resistance and great increase of portal blood flow. With the advance understanding of the mechanisms of LSECs protection, celecoxib may serve as a potential therapeutic candidate for patients with cirrhotic portal hypertension.

Doppler ultrasound to assess the pharmacodynamic effects of splanchnic vasoactive compounds

AIMS

In search of noninvasive biomarkers to assess the pharmacodynamic effects of portal pressure-lowering drugs, the reproducibility of flow measurements in the superior mesenteric artery was evaluated using Doppler ultrasound.

METHODS

A reproducibility study was conducted in 15 healthy male volunteers (18-50 y). Eight ultrasound measurements were performed for each subject: 2 observers each conducted 2 measurements during 2 separate visits. The following flow parameters were captured: peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI), volume flow (VF) and vessel diameter. Reproducibility was assessed by the intraclass correlation coefficient.

RESULTS

Results are presented as intraclass correlation coefficient [95% confidence interval]. The flow parameters PSV, EDV, PI and VF correlated excellently within observer during visit 1 (0.888 [0.748-0.953], 0.910 [0.793-0.962], 0.844 [0.656-0.933] and 0.916 [0.857-0.951], respectively) and visit 2 (0.925 [0.829-0.968], 0.942 [0.863-0.976], 0.883 [0.719-0.954] and 0.915 [0.855-0.951], respectively). Measurements conducted during 2 separate visits by 1 observer correlated well to excellently for PSV, EDV, PI and VF (0.756 [0.552-0.875], 0.836 [0.694-0.916], 0.807 [0.631-0.904] and 0.839 [0.783-0.882], respectively). Measurements conducted by 2 distinct observers correlated well to excellently for PSV, EDV and VF during visit 1 (0.813 [0.584-0.922], 0.884 [0.597-0.945] and 0.786 [0.575-0.899], respectively) and visit 2 (0.779 [0.498-0.912], 0.861 [0.672-0.945], 0.810 [0.553-0.926], respectively). Vessel diameter measurements were poorly reproducible.

CONCLUSION

Doppler ultrasound is a reproducible method for flow measurements in the superior mesenteric artery in a standardized group of healthy volunteers. Therefore, it is a promising technique to assess pharmacodynamic effects of splanchnic vasoactive compounds in early clinical drug development.

Hepatocrinology

Hepatocrinology is defined as a bidirectional, complex relationship between hepatic physiology and endocrine function, hepatic disease and endocrine dysfunction, hepatotropic drugs and endocrine function, and endocrine drugs and hepatic health. The scope of hepatocrinology includes conditions of varied etiology (metabolic, infectious, autoimmune, and invasive) that we term as hepato-endocrine syndromes. This perspective shares the definition, concept, and scope of hepatocrinology and shares insight related to this aspect of medicine. It is hoped that this communication will encourage further attention and research in this critical field.

Self-expandable metallic stents (SEMS) in esophageal varices post-band ulcer refractory bleeding: a retrospective study

Background

Post-variceal band ligation bleeding ulcer is a severe complication with considerable mortality. We tried evaluating self-expandable metallic stent (SEMS) with concern to the ulcer morphology not well studied.

Results

We did a retrospective analysis of patients with bleeding post-band ulcers and treated by SEMS with concern to control bleeding and 6 weeks survival. Twenty-eight patients studied had their age (mean ± S.D.) 57.8 ± 8.6 years, and 85.7% were males. The Child-Pugh score range was 5–12]. Control of bleeding by SEMS was achieved in 23 (82.1%) patients, and overall, 6-week survival was 75%. Both post-band ulcer types B (oozing blood and type C (active spurted) were a risk for 6 weeks mortality (P = 0.04, OR 1.58, CI 95% 1.12–2.23).

Conclusion

SEMS is considered an excellent choice to control esophageal post-banding ulcer bleeding and a definite treatment bridge.

Drug Discovery in Liver Disease Using Kinome Profiling

The liver is one of the most important organs, playing critical roles in maintaining biochemical homeostasis. Accordingly, disease of the liver is often debilitating and responsible for untold human misery. As biochemical nexus, with kinases being master regulators of cellular biochemistry, targeting kinase enzymes is an obvious avenue for treating liver disease. Development of such therapy, however, is hampered by the technical difficulty of obtaining comprehensive insight into hepatic kinase activity, a problem further compounded by the often unique aspects of hepatic kinase activities, which makes extrapolations from other systems difficult. This consideration prompted us to review the current state of the art with respect to kinome profiling approaches towards the hepatic kinome. We observe that currently four different approaches are available, all showing significant promise. Hence we postulate that insight into the hepatic kinome will quickly increase, leading to rational kinase-targeted therapy for different liver diseases.

Pharmacological management of portal hypertension and its complications in children: lessons from adults and opportunities for the future

INTRODUCTION

Portal hypertension (PHT) and its complications in children are thought to be distinct from adult PHT in several areas, including the underlying bio-physiology of a child in which PHT develops, but also because of the pediatric-specific etiologies that drive disease progression. And yet pharmacologic approaches to PHT in children are mainly based on adult data, modified for pediatric practice. This reality has been driven by a lack of data specific to children.

AREAS COVERED

The authors discuss current therapeutic approaches to PHT in children, including management of acute gastrointestinal variceal bleed, pharmacotherapy in prophylaxis, and established and emerging therapies to combat systemic co-morbidities that result from PHT. The few areas where pediatric-specific data exist are highlighted and the many gaps in knowledge that remain unresolved are underscored.

EXPERT OPINION

Despite decades of experience, optimal management of pediatric PHT remains undefined. In large part, this can be directly linked to a lack of basic understanding related to the unique pathophysiology and natural history that defines PHT in children. As a result, meaningful research into the utility and effectiveness of pharmacotherapy in children with PHT remains in its infancy. Large, multi-center, prospective studies will be needed to begin to establish an infrastructure on which a pediatric-specific research agenda can be built.