Role of nucleus accumbens core but not shell in incubation of methamphetamine craving after voluntary abstinence

We recently introduced an animal model to study incubation of drug craving after prolonged voluntary abstinence, mimicking the human condition of relapse after successful contingency management treatment. Here we studied the role of the nucleus accumbens (NAc) in this model. We trained rats to self-administer a palatable solution (sucrose+maltodextrin 1%, 6 h/day, 6 days) and methamphetamine (6 h/day, 12 days). We then evaluated relapse to methamphetamine seeking after 1 and 15 days of voluntary abstinence, achieved via a discrete choice procedure between the palatable solution and methamphetamine (14 days). We used RNAscope in-situ hybridization to quantify the co-labeling of the neuronal activity marker Fos, and dopamine Drd1- and Drd2-expressing medium spiny neurons (MSNs) in NAc core and shell during the incubation tests. Next, we determined the effect of pharmacological inactivation of NAc core and shell by either GABAA and GABAB agonists (muscimol+baclofen, 50+50 ng/side), Drd1-Drd2 antagonist (flupenthixol, 10 µg/side) or the selective Drd1 or Drd2 antagonists (SCH39166 1.0 µg/side or raclopride 1.0 µg/side) during the relapse tests. Incubated methamphetamine seeking after voluntary abstinence was associated with a selective increase of Fos expression in the NAc core, but not shell, and Fos was co-labeled with both Drd1- and Drd2-MSNs. NAc core, but not shell, injections of muscimol+baclofen, flupenthixol, SCH39166, and raclopride reduced methamphetamine seeking after 15 days of abstinence. Together, our results suggest that dopamine transmission through Drd1 and Drd2 in NAc core is critical to the incubation of methamphetamine craving after voluntary abstinence

Resveratrol administration improves intrahepatic endothelial dysfunction and reduces liver fibrosis and portal pressure in CCl4-cirrhotic rats

Background and Aims: In the Western countries, liver cirrhosis is the main cause of portal hypertension, which is defined as a clinical syndrome characterized by an increased hydrostatic pressure within the portal venous system. The importance of this syndrome is defined by the frequency and severity of its complications: gastrointestinal bleeding from ruptured gastroesophageal varices, ascites, hepatorenal syndrome and hepatic encephalopathy. In cirrhosis, the initial factor determining the onset of portal hypertension is the increase in intrahepatic vascular resistance, which is due to the morphological changes of the liver, but also to endothelial dysfunction in the porto-hepatic vascular bed, characterized by an exaggerated response to vasoconstrictors and a deficient response to vasodilators. Resveratrol, a polyphenol found in a variety of fruits, possesses a wide range of beneficial properties, e.g. anti-oxidant and anti-inflammatory activity. In the endothelium resveratrol regulates several vasoactive substances and decreases oxidative stress, both factors involved in the pathophysiology of endothelial dysfunction. This study aimed at evaluating the effects of resveratrol on hepatic and systemic hemodynamics, hepatic endothelial dysfunction and hepatic fibrosis in CCl4-cirrhotic (CH) rats. Methods: Resveratrol (10 or 20mg/kg/day) or its vehicle were administered to CH rats orally for two weeks; then the following measurements were done: a) in vivo: mean arterial pressure (MAP), portal pressure (PP), portal blood flow (PBF) and superior mesenteric artery blood flow (SMABF); b) isolated perfused livers: endothelial function assessed by dose-relaxation curves to acetylcholine; c) assessment of fibrosis: Sirius Red staining of liver sections, collagen-1 mRNA expression and α-smooth muscle actin (α-SMA) protein expression, as a surrogate of hepatic stellate cell activation. Results: Resveratrol administration significantly decreased PP without significant changes in MAP, PBF and SMABF. Reduction in PP was associated with an improved vasodilatory response to acetylcholine and with a significant reduction in liver fibrosis. The decrease in hepatic fibrosis was associated with a reduced collagen-1 mRNA expression and α-SMA protein expression. Conclusions: In cirrhotic rats, resveratrol administration reduces portal pressure by improving liver fibrosis and endothelial dysfunction, suggesting that it may be an ideal supplement in the treatment of portal hypertension in patients with cirrhosis.Introduzione e scopo dello studio: L'ipertensione portale è una condizione fisiopatologica caratterizzata dall'aumento della pressione nel sistema portale che può causare lo sviluppo di manifestazioni cliniche severe quali le emorragie da rottura di varici esofagee e/o gastriche e da gastropatia congestizia, l'ascite, l'encefalopatia epatica e la sindrome epatorenale. L'ipertensione portale può manifestarsi in corso di diverse patologie, fra le quali la più comune nel mondo occidentale è la cirrosi epatica. Nella cirrosi il fattore iniziale alla base dello sviluppo dell'ipertensione portale è l'aumento delle resistenze vascolari intraepatiche, dovuto sia alle alterazioni morfologiche del fegato, sia alla disfunzione endoteliale nel letto vascolare porto-epatico, caratterizzata da un'esagerata risposta a sostanze vasocostrittrici e una risposta ridotta a sostanze vasodilatatrici. Il resveratrolo è un polifenolo di origine vegetale presente nell'uva e nei suoi derivati, negli arachidi, e in diverse altre piante. Tra le numerose proprietà benefiche di questa sostanza sono state studiate soprattutto quella antiossidante ed antinfiammatoria. Il resveratrolo possiede effetti benefici anche a livello endoteliale: è coinvolto nella regolazione di numerose sostanze vasoattive e riduce lo stress ossidativo, fattori entrambi coinvolti nella patogenesi della disfunzione endoteliale. Lo scopo di questo studio era quello di valutare gli effetti del resveratrolo sull'emodinamica sistemica ed epatica, la disfunzione endoteliale epatica e la fibrosi epatica nel modello animale di cirrosi epatica indotta mediante CCl4. Metodi: Il resveratrolo (10 o 20 mg/kg/die) o il suo veicolo sono stati somministrati oralmente per due settimane in ratti cirrotici; successivamente sono state eseguite le seguenti misurazioni: a) in vivo: pressione arteriosa media (PAM), pressione portale (PP), flusso portale (FP) e flusso arterioso mesenterico superiore (FAMS); b) fegati isolati e perfusi: funzione endoteliale valutata attraverso curve dose-risposta all'acetilcolina; c) valutazione della fibrosi epatica: colorazione Sirius Red di sezioni di fegato, espressione dell'mRNA per il collagene-1 ed espressione proteica di α-smooth muscle actin (α-SMA), indice dell'attivazione delle cellule stellate epatiche. Risultati: La somministrazione di resveratrolo ha determinato una riduzione della PP, senza modificazioni significative della PAM, del FP e del FAMS. La riduzione della PP era associata ad un miglioramento della risposta vasodilatatrice all'acetilcolina e della fibrosi a livello epatico. Oltre al miglioramento della fibrosi valutato mediante colorazione Sirius Red, è stata osservata una riduzione dell'espressione dell'mRNA per il collagene-1 e dell' α-smooth muscle actin (α-SMA). Conclusioni: Nei ratti cirrotici il resveratrolo riduce la PP attraverso un miglioramento della fibrosi e della disfunzione endoteliale epatica. Il resveratrolo, dunque, potrebbe essere un supplemento ideale nel trattamento dell'ipertensione portale in pazienti con cirrosi epatica

Combined Pharmacological and Endoscopic Treatment for Worsening Gastroesophageal Varices in Patients with Cirrhosis

BACKGROUND: At the present time, in patients with liver cirrhosis and gastroesophageal varices, primary prophylaxis of variceal bleeding made with combination therapy with non-selective β-blockers (NSBBs) and endoscopic band ligation (EBL) is not recommended. The aim of this study was to evaluate if patients with worsening varices while on NSBBs regimen benefit, in terms of bleeding and survival, from adding treatment with EBL. METHODS: Patients with cirrhosis and endoscopic finding of gastroesophageal varices with high risk feature (increased variceal size and/or development of red signs) during primary prophylaxis with NSBBs, followed at the Unit of Internal Medicine and Hepatology, University and General Hospital of Padova, Italy, from 2012 to 2019, were retrospectively evaluated. When an increased bleeding risk of the varices was confirmed, patients maintained the pharmacological therapy alone or underwent also EBL. The primary endpoint of the study was the rate of variceal bleeding, the secondary endpoint was mortality at 30 months. RESULTS: Compared to patients treated only with NSBBs (n=56), in patients treated also with EBL (n=45), the 30‐month probability of variceal bleeding (29.1% vs 5.1%; P =0.036) was significantly reduced, while the probability of survival was similar (59.6% vs 65.7%; P=0.61). On multivariate analysis, treatment with EBL was found to be a weak protective factor for mortality (HR 0.47, P=0.044). CONCLUSION: In patients with liver cirrhosis, when varices show endoscopic feature of increased haemorrhagic risk, adding EBL to NSBBs is effective in reducing the probability of first bleeding

Clinical role of non-invasive assessment of portal hypertension

Measurement of portal pressure is pivotal in the evaluation of patients with liver cirrhosis. The measurement of the hepatic venous pressure gradient represents the reference method by which portal pressure is estimated. However, it is an invasive procedure that requires significant hospital resources, including experienced staff, and is associated with considerable cost. Non-invasive methods that can be reliably used to estimate the presence and the degree of portal hypertension are urgently needed in clinical practice. Biochemical and morphological parameters have been proposed for this purpose, but have shown disappointing results overall. Splanchnic Doppler ultrasonography and the analysis of microbubble contrast agent kinetics with contrast-enhanced ultrasonography have shown better accuracy for the evaluation of patients with portal hypertension. A key advancement in the non-invasive evaluation of portal hypertension has been the introduction in clinical practice of methods able to measure stiffness in the liver, as well as stiffness/congestion in the spleen. According to the data published to date, it appears to be possible to rule out clinically significant portal hypertension in patients with cirrhosis (i.e., hepatic venous pressure gradient 65 10 mmHg) with a level of clinically-acceptable accuracy by combining measurements of liver stiffness and spleen stiffness along with Doppler ultrasound evaluation. It is probable that the combination of these methods may also allow for the identification of patients with the most serious degree of portal hypertension, and ongoing research is helping to ensure progress in this field

Contribution of Splenic Resistance Arteries to Splanchnic Blood Overflow in Cirrhosis

BOLOGNESI, MASSIMO/0000-0002-9715-5572; DI PASCOLI, MARCO/0000-0001-6996-3196WOS: 000523112500002PubMed: 32242304Background in liver cirrhosis, a marked splanchnic vasodilation causes an increase in portal blood flow, contributing to the development of portal hypertension. Aim To evaluate if, in experimental cirrhosis, a different vascular reactivity exists between splenic and mesenteric components of the splanchnic circulation. Methods Liver cirrhosis was induced in Sprague Dawley rats by common bile duct ligation. in sections of splenic and superior mesenteric arteries, cumulative dose-response curves were obtained. mRNA expression of endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS), and prostaglandin I-2 synthase (PTGIS) was evaluated. Results in cirrhotic rats, mesenteric but not splenic arteries showed a significant increase in endothelium-dependent relaxation to acetylcholine. in control and cirrhotic rats, COX inhibition alone did not significantly change the response of mesenteric arteries to acetylcholine; after inhibiting also NOS, the relaxation was completely abolished in control but only partially decreased in cirrhotic rats. After the inhibition of COX and NOS, the relaxation to acetylcholine was similarly decreased in splenic arteries from control and cirrhotic animals. the contraction induced by phenylephrine of both mesenteric and splenic arteries was decreased in cirrhotic rats. PTGIS mRNA expression did not differ in splenic and mesenteric arteries from control and cirrhotic rats; in cirrhotic rats, eNOS and iNOS mRNA expression was increased in mesenteric but not in splenic vascular bed. Conclusion in cirrhotic rats, a decreased splenic arterial response to vasoconstrictors, rather than an increased response to vasodilators, contributes to splanchnic vasodilation, while in mesenteric arteries also an increased response to vasodilators secondary to, but not only, eNOS and iNOS overexpression, plays a role

Peculiar characteristics of portal-hepatic hemodynamics of alcoholic cirrhosis.

Alcohol-related cirrhosis is a consequence of heavy and prolonged drinking. Similarly to patients with cirrhosis of other etiologies, patients with alcoholic cirrhosis develop portal hypertension and the hepatic, splanchnic and systemic hemodynamic alterations that follow. However, in alcoholic cirrhosis, some specific features can be observed. Compared to viral cirrhosis, in alcohol-related cirrhosis sinusoidal pressure is generally higher, hepatic venous pressure gradient reflects portal pressure better, the portal flow perfusing the liver is reduced despite an increase in liver weight, the prevalence of reversal portal blood flow is higher, a patent paraumbilical vein is a more common finding and signs of hyperdynamic circulations, such as an increased cardiac output and decreased systemic vascular resistance, are more pronounced. Moreover, alcohol consumption can acutely increase portal pressure and portal-collateral blood flow. Alcoholic cardiomyopathy, another pathological consequence of prolonged alcohol misuse, may contribute to the hemodynamic changes occurring in alcohol-related cirrhosis. The aim of this review was to assess the portal-hepatic changes that occur in alcohol-related cirrhosis, focusing on the differences observed in comparison with patients with viral cirrhosis. The knowledge of the specific characteristics of this pathological condition can be helpful in the management of portal hypertension and its complications in patients with alcohol-related cirrhosis

Splanchnic vasodilation and hyperdynamic circulatory syndrome in cirrhosis

Portal hypertension is a clinical syndrome which leads to several clinical complications, such as the formation and rupture of esophageal and/or gastric varices, ascites, hepatic encephalopathy and hepato-renal syndrome. In cirrhosis, the primary cause of the increase in portal pressure is the enhanced resistance to portal outflow. However, also an increase in splanchnic blood flow worsens and maintains portal hypertension. The vasodilatation of arterial splanchnic vessels and the opening of collateral circulation are the determinants of the increased splanchnic blood flow. Several vasoactive systems/substances, such as nitric oxide, cyclooxygenase-derivatives, carbon monoxide and endogenous cannabinoids are activated in portal hypertension and are responsible for the marked splanchnic vasodilatation. Moreover, an impaired reactivity to vasoconstrictor systems, such as the sympathetic nervous system, vasopressin, angiotensin II and endothelin-1, plays a role in this process. The opening of collateral circulation occurs through the reperfusion and dilatation of preexisting vessels, but also through the generation of new vessels. Splanchnic vasodilatation leads to the onset of the hyperdynamic circulatory syndrome, a syndrome which occurs in patients with portal hypertension and is characterized by increased cardiac output and heart rate, and decreased systemic vascular resistance with low arterial blood pressure. Understanding the pathophysiology of splanchnic vasodilatation and hyperdynamic circulatory syndrome is mandatory for the prevention and treatment of portal hypertension and its severe complications

EETs and HO-1 cross-talk

Epoxygenase-dependent metabolites of arachidonc acid, EETs and the heme-oxygenase (HO)-1/carbon monoxide/bilverdin system share similarities in their activity and mediators. They control endothelial function, dilating small arterial vessels, decrease blood pressure, protect the heart from ischemic and hypertensive cardiopathy, control renal circulation and function, promote angiogenesis and organ regeneration, oppose oxidative stress and inflammation, improve diabetes and obesity, have protective effects on the liver, and participate in portal hypertension. Furthermore, EETs induce HO-1, and inhibition of HO-1 abolishes most of the effects of EETs. Thus, a close interaction between the two systems exists, and is relevant in view of their therapeutic potential