Hyperdynamic circulatory syndrome in a mouse model transgenic for SerpinB3.

INTRODUCTION AND OBJECTIVES: SerpinB3 is a cysteine protease inhibitor involved in several biological activities. It is progressively expressed in chronic liver disease, but not in normal liver. The role in vascular reactivity of this serpin, belonging to the same family of Angiotensin II, is still unknown. Our aim was to evaluate the in vivo and in vitro effects of SerpinB3 on systemic and splanchnic hemodynamics. MATERIAL AND METHODS: Different hemodynamic parameters were evaluated by ultrasonography in two colonies of mice (transgenic for human SerpinB3 and C57BL/6J controls) at baseline and after chronic carbon tetrachloride (CCl4) treatment. In vitro SerpinB3 effect on mesenteric microvessels of 5 Wistar-Kyoto rats was analyzed measuring its direct action on: (a) preconstricted arteries, (b) dose-response curves to phenylephrine, before and after inhibition of angiotensin II type 1 receptors with irbesartan. Hearts of SerpinB3 transgenic mice and of the corresponding controls were also analyzed by morphometric assessment. RESULTS: In SerpinB3 transgenic mice, cardiac output (51.6±21.5 vs 30.1±10.8ml/min, p=0.003), hepatic artery pulsatility index (0.85±0.13 vs 0.65±0.11, p<0.001) and portal vein blood flow (5.3±3.2 vs 3.1±1.8ml/min, p=0.03) were significantly increased, compared to controls. In vitro, recombinant SerpinB3 had no direct hemodynamic effect on mesenteric arteries, but it increased their sensitivity to phenylephrine-mediated vasoconstriction (p<0.01). This effect was suppressed by inhibiting angiotensin II type-1 receptors. CONCLUSIONS: In transgenic mice, SerpinB3 is associated with a hyperdynamic circulatory syndrome-like pattern, possibly mediated by angiotensin receptors.

Abnormalities in the 24-hour rhythm of skin temperature in cirrhosis: Sleep-wake and general clinical implications.

BACKGROUND & AIMS: Sleep preparation/onset are associated with peripheral vasodilatation and a decrease in body temperature. The hyperdynamic syndrome exhibited by patients with cirrhosis may impinge on sleep preparation, thus contributing to their difficulties falling asleep. The aim of this study was the assessment of skin temperature, in relation to sleep-wake patterns, in patients with cirrhosis. METHODS: Fifty-three subjects were initially recruited, and 46 completed the study. Of the final 46, 12 were outpatients with cirrhosis, 13 inpatients with cirrhosis, 11 inpatients without cirrhosis and 10 healthy volunteers. All underwent baseline sleep-wake evaluation and blood sampling for inflammatory markers and morning melatonin levels. Distal/proximal skin temperature and their gradient (DPG) were recorded for 24 hours by a wireless device. Over this period subjects kept a sleep-wake diary. RESULTS: Inpatients with cirrhosis slept significantly less well than the other groups. Inpatients and outpatients with cirrhosis had higher proximal temperature and blunted rhythmicity compared to the other groups. Inpatients with/without cirrhosis had higher distal temperature values and blunted rhythmicity compared to the other groups. Inpatients and outpatients with cirrhosis had significantly lower DPG values compared to the other groups, and DPG reached near-zero values several hours later. Significant correlations were observed between temperature and sleep-wake variables and inflammatory markers. CONCLUSIONS: Alterations of distal/proximal skin temperature, their gradient and their time-course were observed in patients with cirrhosis, which may contribute to their sleep disturbances.

Inhibition of epoxyeicosatrienoic acid production in rats with cirrhosis has beneficial effects on portal hypertension by reducing splanchnic vasodilation.

UNLABELLED: In cirrhosis, 11,12-epoxyeicosatrienoic acid (EET) induces mesenteric arterial vasodilation, which contributes to the onset of portal hypertension. We evaluated the hemodynamic effects of in vivo inhibition of EET production in experimental cirrhosis. Sixteen control rats and 16 rats with carbon tetrachloride-induced cirrhosis were studied. Eight controls and eight rats with cirrhosis were treated with the specific epoxygenase inhibitor N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH; 20 mg/kg/day) for 3 consecutive days. Portal blood flow and renal and splenic resistive indexes were calculated through echographic measurements, while portal and systemic pressures were measured through polyethylene-50 catheters. Small resistance mesenteric arteries were connected to a pressure servo controller in a video-monitored perfusion system, and concentration-response curves to phenylephrine and acetylcholine were evaluated. EET levels were measured in tissue homogenates of rat liver, kidney, and aorta, using an enzyme-linked immunosorbent assay. Urinary Na(+) excretion function was also evaluated. In rats with cirrhosis, treatment with MS-PPOH significantly reduced portal blood flow and portal pressure compared to vehicle (13.6 ± 5.7 versus 25.3 ± 7.1 mL/min/100 g body weight, P < 0.05; 9.6 ± 1.1 versus 12.2 ± 2.3 mm Hg, P < 0.05; respectively) without effects on systemic pressure. An increased response to acetylcholine of mesenteric arteries from rats with cirrhosis (50% effect concentration -7.083 ± 0.197 versus -6.517 ± 0.73 in control rats, P < 0.05) was reversed after inhibition of EET production (-6.388 ± 0.263, P < 0.05). In liver, kidney, and aorta from animals with cirrhosis, treatment with MS-PPOH reversed the increase in EET levels. In both controls and rats with cirrhosis, MS-PPOH increased urinary Na(+) excretion. CONCLUSION: In rats with cirrhosis, in vivo inhibition of EET production normalizes the response of mesenteric arteries to vasodilators, with beneficial effects on portal hypertension. (Hepatology 2016;64:923-930).

Changes in gene expression of cytochrome P-450 in liver, kidney and aorta of cirrhotic rats.

INTRODUCTION: Liver cirrhosis is characterized by structural and hemodynamic changes that affect mainly the liver, the kidney and the vascular system. Cytochrome P-450 (CYP) is a variegated family of enzymes that, among many other activities, metabolize arachidonic acid to the vasoactive epoxyeicosatrienoic acids (EETs). AIM: To investigate in an animal model of cirrhosis the m-RNA expression of CYPs in liver, kidney and aorta and to evaluate the effect of epoxygenase inhibition by N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH). METHODS: In aorta, liver and kidney from 3 control, 3 cirrhotic and 6 cirrhotic rats treated with MS-PPOH, quantitative real-time PCR reactions were performed and the m-RNA expression of CYP2J3, CYP2J4, CYP2J10, CYP2C11, CYP2C12 and CYP2C23 was calculated. RESULTS: In cirrhotic rats, the gene expression of hepatic CYP2C11 and CYP2J10 was increased, of aortic CYP2J4 was increased, of aortic CYP2C12 was reduced and of renal CYP2C11 was increased. In cirrhotic rats, MS-PPOH reduced CYP2J10 hepatic and CYP2C11 renal gene expression to levels similar to the ones of control rats. CONCLUSIONS: Changes in CYPs gene expression may contribute to the hemodynamic alterations typical of cirrhosis. The altered gene expression of CYPs can, in some cases, be reversed by epoxygenase inhibition.

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.

Hepatic osteodystrophy.

Metabolic disturbances of bone are frequent in patients with chronic liver disease. The prevalence of osteoporosis among patients with advanced chronic liver disease is reported between 12% and 55%; it is higher in primary biliary cirrhosis. All patients with advanced liver disease should be screened for osteoporosis with a densitometry, especially if the etiology is cholestatic and in the presence of other risk factors. Clinical relevance of hepatic osteodystrophy increases after liver transplantation. After liver transplant, a rapid loss of bone mineral density can be detected in the first 6 months, followed by stabilization and slight improvement of the values. At the time of transplantation, bone density values are very important prognostic factors. Therapy of hepatic osteodystrophy is based primarily on the control of risk factors: cessation of tobacco and alcohol assumption, reduction of caffeine ingestion, exercise, supplementation of calcium and vitamin D, limitation of drugs such as loop diuretics, corticosteroids, cholestyramine. Bisphosphonates have been proposed for the therapy of osteoporosis in patients with liver disease, particularly after liver transplantation. The possible side effects of oral administration of bisphosphonates, such as the occurrence of esophageal ulcerations, are of particular concern in patients with liver cirrhosis and portal hypertension, due to the risk of gastrointestinal hemorrhage from ruptured esophageal varices, although this risk is probably overestimated.

Hypoalbuminemia.

Hypoalbuminemia is frequently observed in hospitalized patients and it can be associated with several different diseases, including cirrhosis, malnutrition, nephrotic syndrome and sepsis. Regardless of its cause, hypoalbuminemia has a strong predictive value on mortality and morbidity. Over the years, the rationale for the use of albumin has been extensively debated and the indications for human serum albumin supplementation have changed. As the knowledge of the pathophysiological mechanisms of the pertinent diseases has increased, the indications for intravenous albumin supplementation have progressively decreased. The purpose of this brief article is to review the causes of hypoalbuminemia and the current indications for intravenous administration of albumin. Based on the available data and considering the costs, albumin supplementation should be limited to well-defined clinical scenarios and to include patients with cirrhosis and spontaneous bacterial peritonitis, patients with cirrhosis undergoing large volume paracentesis, the treatment of type 1 hepatorenal syndrome, fluid resuscitation of patients with sepsis, and therapeutic plasmapheresis with exchange of large volumes of plasma. While albumin supplementation is accepted also in other clinical situations such as burns, nephrotic syndrome, hemorrhagic shock and prevention of hepatorenal syndrome, within these contexts it does not represent a first-choice treatment nor is its use supported by widely accepted guidelines.

Increased myoendothelial gap junctions mediate the enhanced response to epoxyeicosatrienoic acid and acetylcholine in mesenteric arterial vessels of cirrhotic rats.

BACKGROUND: Cirrhotic portal hypertension is characterized by mesenteric arterial vasodilation and hyporeactivity to vasoconstrictors. AIM: We evaluated the role of epoxyeicosatrienoic acid (EET) and of myoendothelial gap junctions (GJ) in the haemodynamic alterations of experimental cirrhosis. METHODS: Thirty-five control rats and 35 rats with carbon tetrachloride (CCl(4))-induced cirrhosis were studied. Small resistance mesenteric arteries (diameter <350 µm) were connected to a pressure servo controller in a video-monitored perfusion system. Concentration-response curves to acetylcholine (ACh) were evaluated in mesenteric arteries pre-incubated with indomethacin, N(G)-nitro-L-arginine-methyl-ester and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one before and after the epoxygenase inhibitor miconazole or 18α-glycyrrhetinic acid (18α-GA) (GJ inhibitor). EC(50) was calculated. Concentration-response curves to 11,12-EET were also evaluated. mRNA and protein expression of connexins (Cxs) in the mesenteric arteries was evaluated by real-time PCR and immunohistochemistry. RESULTS: The ACh response was increased in cirrhotic rats (EC(50): -6.55±0.10 vs. -6.01±0.10 log[M]; P<0.01) and was blunted by miconazole only in cirrhotic animals. 18α-GA blunted the response to ACh more in cirrhotic than that in control rats (P<0.05). Concentration-response curves to 11,12-EET showed an increased endothelium-dependent vasodilating response in cirrhotic rats (P<0.05); the BK(Ca) inhibitor Iberiotoxin (25 nM) blocked the response in normal rats but not in cirrhotic rats, while 18α-GA blunted the response in cirrhotic rats but not in control rats. An increased mRNA and protein expression of Cx40 and Cx43 in cirrhotic arteries was detected (P<0.05). CONCLUSIONS: The increased nitric oxide/PGI(2)-independent vasodilation of mesenteric arterial circulation in cirrhosis is because of, at least in part, hyperreactivity to 11,12-EET through an increased expression of myoendothelial GJs.