Zolmitriptan: a novel portal hypotensive agent which synergizes with propranolol in lowering portal pressure

Effects of new generation triptans - frovatriptan and almotriptan - on hemodynamic parameters in intact male and female rats

The introduction of the second generation triptans in clinical and experimental practice was a major progress in the pharmacotherapy of migraine. Frovatriptan is a second generation triptan with strong 5-HT1B/1D serotonergic agonism and low 5-HT1A/7 receptor affinity, while almotriptan possesses not only the typical 5-HT1B/1D receptor agonist activity, but shows an affinity to the 5-HT1F receptor. The aim of our study was to assess the impact of frovatriptan and almotriptan on hemodynamics in male and female rats. We used a non-invasive "tail-cuff" method to measure the arterial blood pressure. Female and male Wistar rats were treated separately with high and low dosages of frovatriptan and almotriptan. Male and female rats showed reduction in all hemodynamic parameters, but only male rats showed an increase in the heart rate. In general, we could say that both almotriptan and frovatriptan potentiate cardiovascular safety.

Animal models of portal hypertension

Chronic liver diseases ultimately lead to cirrhosis and portal hypertension (PHT). Indeed, PHT is a major cause of severe complications, while medical treatment is limited to non-selective beta blockers. Sophisticated animal models are needed to investigate novel treatment options for different etiologies of liver disease, effective anti-fibrotic agents as well as vasoactive drugs against PHT. In this review, we present some of the most common animal models of liver disease and PHT - including pre-hepatic, intra-hepatic and post-hepatic PHT in rodents. Methodology for induction, considerations for disease etiology, advantages and limitations and practical issues of these animal models are discussed. The appropriate and sensible use of animal models in preclinical research supporting the 3R concept of replacement, reduction and refinement is highlighted.

Novel treatment options for portal hypertension

Portal hypertension is most frequently associated with cirrhosis and is a major driver for associated complications, such as variceal bleeding, ascites or hepatic encephalopathy. As such, clinically significant portal hypertension forms the prelude to decompensation and impacts significantly on the prognosis of patients with liver cirrhosis. At present, non-selective β-blockers, vasopressin analogues and somatostatin analogues are the mainstay of treatment but these strategies are far from satisfactory and only target splanchnic hyperemia. In contrast, safe and reliable strategies to reduce the increased intrahepatic resistance in cirrhotic patients still represent a pending issue. In recent years, several preclinical and clinical trials have focused on this latter component and other therapeutic avenues. In this review, we highlight novel data in this context and address potentially interesting therapeutic options for the future.

Combined administration of propranolol + AG490 offers better effects on portal hypertensive rats with cirrhosis

BACKGROUND AND AIMS

AG490, the specific inhibitor of JAK2/STAT3 signaling, has been shown to decrease portal pressure, splanchnic hyperdynamic circulation and liver fibrosis in cirrhotic rats. Nonselective betablockers such as propranolol are the only drugs recommended in the treatment of portal hypertension. The aim of this study was to explore the combinative effect of treatment with propranolol and AG490 on portal hypertension.

METHODS

Rats induced by common bile duct ligation were treated with vehicle, AG490, propranolol, or AG490 + propranolol for 2 weeks. Hemodynamics parameters were assessed. Expressions of phospho-STAT3 protein and its down-regulated cytokines in splanchnic organs were detected by ELISA or western blot. Lipopolysaccharide binding protein (LBP) and IL-6 were assessed by ELISA or western blot. Characterization of liver and mesentery was performed by histological analyses.

RESULTS

Highly expressed phospho-STAT3 protein in cirrhotic rats could successfully be inhibited by AG490 or AG490 + propranolol treatments but not by propranolol alone. Both AG490 and propranolol significantly reduced portal pressure and hyperdynamic splanchnic circulation, and combination of AG490 and propranolol achieved an additive effect than with either drug alone. AG490, alone or in combination with propranolol, inhibited liver fibrosis, splenomegaly and splanchnic angiogenesis. Increased markers of bacterial translocation (LBP and IL6) were greatly reduced by propranolol but not by AG490.

CONCLUSIONS

The combination of propranolol and AG490 caused a greater improvement of portal hypertension and might therefore offer a potentially promising therapy in the portal hypertension treatment.

Alkaloids in Erythrina by UPLC-ESI-MS and In Vivo Hypotensive Potential of Extractive Preparations

Erythrina species are used in popular medicine as sedative, anxiolytic, anti-inflammatory, and antihypertensive. In this work, we investigated the chemical composition of extracts obtained from leaves of E. falcata and E. crista-galli. The hypotensive potential of E. falcata and the mechanism of action were also studied. The extracts were obtained by maceration and infusion. The total content of phenolic compounds and flavonoids was estimated by spectrophotometric methods. The chemical constituents were studied performing a chromatographic analysis by UPLC-ESI-MS. For in vivo protocols, blood pressure and heart rate were measured by the invasive hemodynamic monitoring method. Different concentrations of extracts and drugs such as L-NAME, losartan, hexamethonium, and propranolol were administrated i.v. The results of total phenolic contents for E. falcata and E. crista-galli were 1.3193-1.4989 mgGAE/mL for maceration and 0.8771-0.9506 mgGAE/mL for infusion. In total flavonoids, the content was 7.7829-8.1976 mg RE/g for maceration and 9.3471-10.4765 RE mg/g for infusion. The chemical composition was based on alkaloids, suggesting the presence of erythristemine, 11β-methoxyglucoerysodine, erysothiopine, 11β-hydroxyerysodine-glucose, and 11-hydroxyerysotinone-rhamnoside. A potent dose-dependent hypotensive effect was observed for E. falcata, which may be related to the route of β-adrenergic receptors.