Lack of renal improvement with nonselective endothelin antagonism with tezosentan in type 2 hepatorenal syndrome

Pathophysiology of Hepatorenal Syndrome

Hepatorenal syndrome type 1 (HRS-1) is a unique form of acute kidney injury that affects individuals with decompensated cirrhosis with ascites. The primary mechanism leading to reduction of kidney function in HRS-1 is hemodynamic in nature. Cumulative evidence points to a cascade of events that led to a profound reduction in kidney perfusion. A state of increased intrahepatic vascular resistance characteristic of advanced cirrhosis and portal hypertension is accompanied by maladaptive peripheral arterial vasodilation and reduction in systemic vascular resistance and mean arterial pressure. As a result of a fall in effective arterial blood volume, there is a compensatory activation of the sympathetic nervous system and the renin-angiotensin system, local renal vasoconstriction, loss of renal autoregulation, decrease in renal blood flow, and ultimately a fall in glomerular filtration rate. Systemic release of nitric oxide stimulated by the fibrotic liver, bacterial translocation, and inflammation constitute key components of the pathogenesis. While angiotensin II and noradrenaline remain the critical mediators of renal arterial and arteriolar vasoconstriction, other novel molecules have been recently implicated. Although the above-described mechanistic pathway remains the backbone of the pathogenesis of HRS-1, other noxious elements may be present in advanced cirrhosis and likely contribute to the renal impairment. Direct liver-kidney crosstalk via the hepatorenal sympathetic reflex can further reduce renal blood flow independently of the systemic derangements. Tense ascites may lead to intraabdominal hypertension and abdominal compartment syndrome. Cardio-hemodynamic processes have also been increasingly recognized. Porto-pulmonary hypertension, cirrhotic cardiomyopathy, and abdominal compartment syndrome may lead to renal congestion and complicate the course of HRS-1. In addition, a degree of ischemic or toxic (cholemic) tubular injury may overlap with the underlying circulatory dysfunction and further exacerbate the course of acute kidney injury. Improving our understanding of the pathogenesis of HRS-1 may lead to improvements in therapeutic options for this seriously ill population.

Reappraising the spectrum of AKI and hepatorenal syndrome in patients with cirrhosis

The occurrence of acute kidney injury (AKI) in patients with end-stage liver disease constitutes one of the most challenging clinical scenarios in in-hospital and critical care medicine. Hepatorenal syndrome type 1 (HRS-1), which is a specific type of AKI that occurs in the context of advanced cirrhosis and portal hypertension, is associated with particularly high mortality. The pathogenesis of HRS-1 is largely viewed as a functional derangement that ultimately affects renal vasculature tone. However, new insights suggest that non-haemodynamic tubulo-toxic factors, such as endotoxins and bile acids, might mediate parenchymal renal injury in patients with cirrhosis, suggesting that concurrent mechanisms, including those traditionally associated with HRS-1 and non-traditional factors, might contribute to the development of AKI in patients with cirrhosis. Moreover, histological evidence of morphological abnormalities in the kidneys of patients with cirrhosis and renal dysfunction has prompted the functional nature of HRS-1 to be re-examined. From a clinical perspective, a diagnosis of HRS-1 guides utilization of vasoconstrictive therapy and decisions regarding renal replacement therapy. Patients with cirrhosis are at risk of AKI owing to a wide range of factors. However, the tools currently available to ascertain the diagnosis of HRS-1 and guide therapy are suboptimal. Short of liver transplantation, goal-directed haemodynamically targeted pharmacotherapy remains the cornerstone of treatment for this condition; improved understanding of the underlying pathogenic mechanisms might lead to better clinical outcomes. Here, we examine our current understanding of the pathophysiology of HRS-1 and existing challenges in its diagnosis and treatment.

Vascular syndromes in liver cirrhosis

Liver cirrhosis is associated with multiple vascular syndromes affecting almost all body systems. Many of these syndromes are directly related to impaired liver function and sometimes reversible after liver transplantation while others arise secondary to portal hypertension and ascites. Altered expression of angiogenic and vasoactive compounds (most importantly nitric oxide), endothelial dysfunction, dysregulated neurohormonal control, and systemic inflammatory state play differential roles in mediating homeostatic instability and abnormal vasogenic response. Important vascular features encountered in liver disease include portal hypertension, splanchnic overflow, abnormal angiogenesis and shunts, portopulmonary syndrome, hepatopulmonary syndrome, and systemic hyperdynamic circulation. Redistribution of effective circulatory volume deviating from vital organs and pooling in splanchnic circulation is also encountered in liver patients which may lead to devastating outcomes as hepatorenal syndrome. Etiologically, vascular syndromes are not isolated phenomena and vascular dysfunction in one system may lead to the development of another in a different system. This review focuses on understanding the pathophysiological factors underlying vascular syndromes related to chronic liver disease and the potential links among them. Many of these syndromes are associated with high mortality, thus it is crucial to look for early biomarkers for these syndromes and develop novel preventive and therapeutic strategies.

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 (ET_A) 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 ET_A 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, ET_A 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 (ET_A) upregulation, and subsequent extracellular signal-regulated kinase activation in renal medulla. Pretreatment with ET_A 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.

Promising utilization areas of therapeutic plasmapheresis in cardiovascular surgery practice

OBJECTIVE

Apheresis is performed for treatment of numerous diseases by removing auto-antibodies, antigen-antibody complexes, allo-antibodies, paraproteins, non-Ig proteins, toxins, exogenous poisons. In current study, we present our experience of using therapeutic plasma exchange (TPE) in patients with different types of clinical scenarios.

METHODS

Between January 2013 and May 2016, we retrospectively presented the results of 64 patients in whom postoperative TPE was performed in ICU setting after cardiac surgery. Patients were grouped into four as; 1-sepsis (n = 26), 2-hepatorenal syndrome(n = 24), 3-antibody mediated rejection(AMR) following heart transplantation(n = 4) and 4-right heart failure(RHF) after left ventricular asist device(LVAD)(n = 10). Hemodynamic parameters were monitored constantly, pre- and post-procedure peripheral blood tests including renal and liver functions and daily complete blood count (CBC), sedimentation, C-reactive protein and procalcitonin (ng/ml) levels were studied.

RESULTS

The mean age was 61 ± 17.67 years old and 56.25% (n = 36) were male. Mean Pre TPE left ventricular ejection fraction (LVEF) (%), central venous pressure (CVP)(mmHg) pulmonary capillary wedge pressure (PCWP)(mmHg) and pulmonary arterial pressure (PAP)(mmHg) were measured as 41.8 ± 8.1, 15.5 ± 4.4, 17.3 ± 3.24 and 39.9 ± 5.4, respectively. Procalcitonin (ng/ml) level of patients undergoing TPE due to sepsis was significantly reduced from 873 ± 401 ng/ml to 248 ± 132 ng/ml. Seventeen (26.5%) patients died in hospital during treatment, mean length of intensive care unit (ICU) stay(days) was 13.2 ± 5.1.

CONCLUSION

This study shows that TEP is a safe and feasible treatment modality in patients with different types of complications after cardiac surgery and hopefully this study will lead to new utilization areas.

Hepatorenal syndrome

Hepatorenal syndrome (HRS) is a form of kidney function impairment that characteristically occurs in cirrhosis. Recent changes in terminology have led to acute HRS being referred to as acute kidney injury (AKI)-HRS and chronic HRS as chronic kidney disease (CKD)-HRS. AKI-HRS is characterized by a severe impairment of kidney function owing to vasoconstriction of the renal arteries in the absence of substantial abnormalities in kidney histology. Pathogenetic mechanisms involve disturbances in circulatory function due to a marked splanchnic arterial vasodilation, which triggers the activation of vasoconstrictor factors. An intense systemic inflammatory reaction that is characteristic of advanced cirrhosis may also be involved. The main triggering factors of AKI-HRS are bacterial infections, particularly spontaneous bacterial peritonitis. The diagnosis of AKI-HRS is a challenge because of a lack of specific diagnostic tools and mainly involves the differential diagnosis from other forms of AKI, particularly acute tubular necrosis. The prognosis of patients with AKI-HRS is poor, with a median survival of ≤3 months. The ideal treatment for AKI-HRS is liver transplantation in patients without contraindications. Medical therapy consists of vasoconstrictor drugs to counteract splanchnic arterial vasodilation together with volume expansion with albumin. Effective measures to prevent AKI-HRS include early identification and treatment of bacterial infections and the administration of albumin in patients with spontaneous bacterial peritonitis.

Therapeutic potential of endothelin receptor antagonism in kidney disease

Our growing understanding of the role of the endothelin (ET) system in renal physiology and pathophysiology is from emerging studies of renal disease in animal models and humans. ET receptor antagonists reduce blood pressure and proteinuria in chronic kidney disease and cause regression of renal injury in animals. However, the therapeutic potential of ET receptor antagonism has not been fully explored and clinical studies have been largely limited to patients with diabetic nephropathy. There remains a need for more work in nondiabetic chronic kidney disease, end-stage renal disease (patients requiring maintenance dialysis and those with a functioning kidney transplant), ischemia reperfusion injury, and sickle cell disease. The current review summarizes the most recent advances in both preclinical and clinical studies of ET receptor antagonists in the field of kidney disease.

Pathogenesis of Hepatorenal Syndrome: Implications for Therapy

Patients with cirrhosis are prone to develop acute kidney injury (AKI) due to a number of causes, including bacterial infections with or without septic shock, hypovolemia, administration of nephrotoxic drugs, and intrinsic kidney diseases, among others. Most importantly, patients with advanced cirrhosis develop a distinctive cause of AKI, characterized by rapidly progressive glomerular filtration rate loss associated with marked disturbances in circulatory function in the absence of obvious pathologic abnormalities in the kidneys, known as hepatorenal syndrome (HRS). Decreased kidney function results from intense renal vasoconstriction secondary to the complex circulatory changes of cirrhosis with splanchnic vasodilatation and effective hypovolemia. Beyond activation of vasoactive systems, factors including impaired renal blood flow autoregulation and systemic inflammation may play a role in the development of HRS. Most patients improve with albumin and vasopressors; however, the prognosis of HRS remains very poor. Novel biomarkers may be helpful in distinguishing HRS from other causes of AKI in patients with cirrhosis.

The role of endothelin-1 and endothelin receptor antagonists in inflammatory response and sepsis

Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor, mainly secreted by endothelial cells. It acts through two types of receptors: ETA and ETB. Apart from a vasoconstrictive action, ET-1 causes fibrosis of the vascular cells and stimulates production of reactive oxygen species. It is claimed that ET-1 induces proinflammatory mechanisms, increasing superoxide anion production and cytokine secretion. A recent study has shown that ET-1 is involved in the activation of transcription factors such as NF-κB and expression of proinflammatory cytokines including TNF-α, IL-1, and IL-6. It has been also indicated that during endotoxaemia, the plasma level of ET-1 is increased in various animal species. Some authors indicate a clear correlation between endothelin plasma level and morbidity/mortality rate in septic patients. These pathological effects of ET-1 may be abrogated at least partly by endothelin receptor blockade. ET-1 receptor antagonists may be useful for prevention of various vascular diseases. This review summarises the current knowledge regarding endothelin receptor antagonists and the role of ET-1 in sepsis and inflammation.

Kidney injury in cirrhosis: pathophysiological and therapeutic aspects of hepatorenal syndromes

Acute kidney injury (AKI) is frequent in patients with cirrhosis. AKI and hyponatraemia are major determinants of the poor prognosis in advanced cirrhosis. The hepatorenal syndrome (HRS) denotes a functional and potential reversible impairment of renal function. Type 1 HRS, a special type of AKI, is a rapidly progressive AKI, whereas the renal function in type 2 HRS decreases more slowly. HRS is precipitated by factors such as sepsis that aggravate the effective hypovolaemia in decompensated cirrhosis, by lowering arterial pressure and cardiac output and enhanced sympathetic nervous activity. Therefore, attempts to prevent and treat HRS should seek to improve liver function and to ameliorate arterial hypotension, central hypovolaemia and cardiac output, and to reduce renal vasoconstriction. Ample treatment of HRS is important to prevent further progression and death, but as medical treatment only modestly improves long-term survival, these patients should always be considered for liver transplantation. Hyponatraemia, defined as serum sodium <130 mmol/L, is common in patients with decompensated cirrhosis. From a pathophysiological point of view, hyponatraemia is related to an impairment of renal solute-free water excretion most likely caused by an increased vasopressin secretion. Patients with cirrhosis mainly develop hypervolaemic hyponatraemia. Current evidence does not support routine use of vaptans in the management of hyponatraemia in cirrhosis.

Survival benefits of terlipressin and non-responder state in hepatorenal syndrome: a meta-analysis

Objectives:

Terlipressin improves renal function in hepatorenal syndrome (HRS) is a known fact. However the reason for lack of its long-term survival benefits despite improvement in renal function remains unclear. The aim of this study was to analyze the survival benefits of terlipressin in HRS and to address the issue of non-responder state to terlipressin.

Materials and Methods:

Electronic databases and relevant articles were searched for all types of studies related to HRS and use of terlipressin in HRS. Reduction in all-cause mortality rate was the primary outcome measure. Reduction in mortality rate due to HRS and other causes of death were also analyzed.

Results:

With total 377 patients analyzed from eight eligible studies; terlipressin reduced all-cause mortality rate by 15% (Risk Difference: -0.15%, 95% CI:-0.26 to -0.03). Reduction in the mortality rate due to HRS at three months was 9% (Risk Difference:-0.09%, 95% CI:-0.18 to 0.00).

Conclusion:

Terlipressin has long term survival benefits perhaps at least up to three months but only with HRS as a cause of death not for other causes of death. Benefits and role of antioxidants like N- Acetylcysteine (NAC) in non-responder patients’ needs to be studied further. Long-term use of low dose terlipressin (<4mg/d) plus albumin and addition of antioxidant NAC to this regimen may help in improving both HRS reversal rate and survival rate in non-responders to terlipressin.

Medical management of hepatorenal syndrome

Hepatorenal syndrome (HRS) is defined as the occurrence of renal dysfunction in a patient with end-stage liver cirrhosis in the absence of another identifiable cause of renal failure. The prognosis of HRS remains poor, with a median survival without liver transplantation of <6 months. However, understanding the pathogenesis of HRS has led to the introduction of treatments designed to increase renal perfusion and mean arterial blood pressure using vasopressors and albumin, which has led to improvement in renal function in ∼50% of patients.

Hepatorenal syndrome: a severe, but treatable, cause of kidney failure in cirrhosis

Hepatorenal syndrome (HRS) is a unique type of kidney failure that occurs in advanced cirrhosis. It is characterized by functional impairment of the kidneys due to vasoconstriction of the renal arteries in the setting of preserved tubular function and absence of significant histologic abnormalities. Renal vasoconstriction in HRS is due to severe vasodilation of the splanchnic arteries associated with portal hypertension, leading to a decrease in effective arterial blood volume and arterial pressure. HRS commonly develops after a trigger, usually a bacterial infection, that disrupts the arterial circulation, but it also may occur spontaneously. There are 2 forms of HRS: type 1 is characterized by an acute progressive decrease in kidney function and very short survival without treatment, whereas type 2 features stable less severe kidney failure and longer survival compared with type 1. A liver transplant is the preferred treatment for HRS. Pharmacologic treatment with vasoconstrictors to reverse splanchnic vasodilation, together with albumin, is effective in 40%-50% of patients with type 1 HRS and improves survival. The drug of choice is the vasopressin analogue terlipressin. Renal replacement therapy should not be used as first-line therapy.

Circulating endotoxin and interleukin-6 levels are associated with Doppler-evaluated pulmonary vascular resistance in cirrhotic patients

PURPOSE

Endotoxin and interleukin-6 levels (IL-6) have been involved in the development of pulmonary hypertension (PH) in non-cirrhotic experimental models and subjects. High circulating levels of both substances have been detected in cirrhosis. The association between circulating endotoxin and IL-6 levels and echocardiographically evaluated pulmonary vascular resistance (PVR) in cirrhotic patients are investigated.

METHODS

Thirty-seven cirrhotic patients were studied: 25 with PVR <120 dynes s cm(-5) (group 1) and 12 with PVR >120 dynes s cm(-5) (group 2). Plasma endotoxin and serum IL-6 levels were measured. The PVR and cardiac output (CO) by Doppler ultrasound, mean arterial pressure (MAP), and systemic vascular resistance (SVR) as the ratio MAP/CO were evaluated.

RESULTS

Child-Pugh scores, MAP, CO, and SVR were similar in both groups. Endotoxin levels were correlated significantly with IL-6 levels (r = 0.342; P = 0.03). Endotoxin and IL-6 levels were significantly higher in group 2 compared to group 1 (2.26 [0.39-8.4] vs. 0.85 [0.37-7.6] EU/mL; P = 0.04 and 37.4 [7.85-106.5] vs. 8.36 [3.15-53.7] pg/mL; P < 0.001, respectively). The PVR was correlated significantly with endotoxin levels in group 2 (r = 0.587; P = 0.04) and with IL-6 levels in group 1 (r = 0.529; P = 0.01) and group 2 (r = 0.760; P = 0.004), respectively.

CONCLUSIONS

Our results suggest that endotoxin and IL-6 may contribute to cirrhosis-associated PH. In this regard, modulation of these substances could improve pulmonary pressures in cirrhotic patients.

Critical care management of patients with end-stage liver disease

OBJECTIVES

To review the management of complications related to end-stage liver disease in the intensive care unit. The goal of this review is to address topics important to the practicing physician.

DATA SOURCES

We performed an organ system-based PubMed literature review focusing on the diagnosis and treatment of critical complications of end-stage liver disease. DATA SYNTHESIS AND FINDINGS: When available, preferential consideration was given to randomized controlled trials. In the absence of trials, observational and retrospective studies and consensus opinions were included. We present our recommendations for the neurologic, cardiovascular, pulmonary, gastrointestinal, renal, and infectious complications of end-stage liver disease.

CONCLUSIONS

Complications related to end-stage liver disease have significant morbidity and mortality. Management of these complications in the intensive care unit requires awareness and expertise among physicians from a wide variety of fields.

Differential effects of terlipressin on pulmonary and systemic hemodynamics in patients with cirrhosis and pulmonary hypertension: an echo study

Terlipressin has been associated with pulmonary arterial vasodilation in patients with pulmonary hypertension (PH). We investigated the effects of terlipressin on pulmonary vascular resistance (PVR) in patients with cirrhosis without and with PH. Pulmonary vascular resistance and cardiac output (CO) by Doppler ultrasound, mean arterial pressure (MAP), and systemic vascular resistance (SVR) were evaluated in patients with cirrhosis with PVR -120 dyne s cm⁻⁵ (group 1, n = 20) and PVR >120 dyne s cm⁻⁵ (group 2, n = 10) before and 30 minutes after terlipressin infusion (2 mg). After terlipressin, PVR increased significantly in group 1 (96.1 ± 20.2 vs 85.1 ± 18 dyne s cm⁻⁵; P = .004) but decreased significantly in group 2 (170.4 ± 37.8 vs 157.8 ± 28.1 dyne s cm⁻⁵; P= .04). Pulmonary vascular resistance changes in group 2 correlated significantly with baseline PVR (r = -0.632; P = .04). Terlipressin induced a significant increase in MAP and SVR and a significant decrease in CO in both groups. Terlipressin significantly reduces pulmonary pressures in patients with cirrhosis having PH together with systemic hemodynamic improvement.

Renal and circulatory dysfunction in cirrhosis: current management and future perspectives

Chronic liver diseases are amongst the top leading causes of death in Europe as well as in other areas of the world. Chronic liver diseases are characterized by unrelenting progression of liver inflammation and fibrosis over a prolonged period of time, usually more than 20 years, which may eventually lead to cirrhosis. Advanced cirrhosis leads to a complex syndrome of chronic liver failure which involves many different organs besides the liver, including the brain, heart and systemic circulation, adrenal glands, lungs, and kidneys. The high morbidity and mortality secondary to chronic liver failure is due to complications related to the dysfunction of these organs, either alone or, more frequently, in combination. Understanding the mechanisms leading to organ dysfunction is crucial to the development of strategies for treatment and prevention of complications of cirrhosis. This article reviews our current knowledge, as well as future perspectives, on the management of circulatory and renal dysfunction in chronic liver failure.

Optimal management of hepatorenal syndrome in patients with cirrhosis

Hepatorenal syndrome (HRS) is a functional renal failure that often occurs in patients with cirrhosis and ascites. HRS develops as a consequence of a severe reduction of effective circulating volume due to both an extreme splanchnic arterial vasodilatation and a reduction of cardiac output. There are 2 different types of HRS. Type 1 HRS, which is often precipitated by a bacterial infection, especially spontaneous bacterial peritonitis, is characterized by a rapidly progressive impairment of renal function. Despite its functional origin, the prognosis of type 1 HRS is very poor. Type 2 HRS is characterized by a stable or slowly progressive renal failure so that its main clinical consequence is not acute renal failure but refractory ascites and its impact on prognosis is less negative. New treatments (vasoconstrictors plus albumin, transjugular portosystemic shunt, and molecular adsorbent recirculating system), which were introduced in the past 10 years, are effective in improving renal function in patients with HRS. Among these treatments vasoconstrictors plus albumin can also improve survival in patients with type 1 HRS. Thus, this therapeutic approach has changed the management of this severe complication in patients with advanced cirrhosis.

Treatment of hepatorenal syndrome

Hepatorenal syndrome (HRS) is a type of renal failure that occurs in patients with advanced cirrhosis. It is a result of splanchnic arterial vasodilation, renal vasoconstriction, reduced effective arterial volume, and potentially reduced cardiac output. Often, HRS is a fatal complication, and the only definitive treatment currently available is liver or liver-kidney transplantation. A number of other treatment modalities have been tested for the management of HRS, but most evidence is derived from small noncontrolled studies. The primary role of these treatment options is to provide a bridge to liver transplantation. Treatment may also provide acute reversal of renal failure and some symptomatic relief, but relapse is a common occurrence. The best therapeutic options appear to be those that reverse portal hypertension, splanchnic vasodilation, and/or renal vasoconstriction. Vasopressin analogs, particularly terlipressin, have emerged as the preferred pharmacologic therapies for management of HRS. Albumin is an appropriate adjunctive therapy to terlipressin and can be used to prevent HRS in patients with spontaneous bacterial peritonitis. Transjugular intrahepatic portosystemic shunt may provide a surgical option for qualified patients with HRS. Octreotide is ineffective as monotherapy but may be used as adjunctive therapy to other vasoactive agents. Dopamine agonists, endothelin antagonists, natriuretic peptides, and nitric oxide synthase inhibitors have not been effective for reversing HRS. Artificial hepatic support therapies have demonstrated the ability to improve laboratory abnormalities in patients with HRS, but their effect on clinical outcomes has not been determined. The role of renal replacement therapies or the newer artificial hepatic support therapies need further evaluation before they can be routinely recommended.

Influence of liver cirrhosis on the pharmacokinetics, pharmacodynamics, and safety of tezosentan

This study investigates the pharmacokinetics, pharmacodynamics, and safety of the parenteral endothelin receptor antagonist tezosentan in patients with Child-Pugh classification B/C liver impairment. Cohorts I and II consist of 5 and 11 patients, respectively, with low serum bilirubin (<or=3.0 mg/dL) who receive intravenous tezosentan at 0.2 mg/h for 24 hours followed by 1.0 mg/h for 24 hours (cohort I) or 1.0 mg/h for 24 hours followed by 5.0 mg/h for 24 hours (cohort II). Cohort III (5 patients) receives the same treatment as cohort II but patients have high serum bilirubin (3.5-12 mg/dL). Each cohort includes 1 or 2 placebo patients (in total 4 patients). Compared with a historical control group of healthy subjects, the exposure to tezosentan is 3.1- and 8.5-fold greater in cohorts II and III, respectively. Patients are more sensitive than healthy subjects to the pharmacodynamic effects of tezosentan, as reflected in increases in endothelin-1 concentrations. Tezosentan is well tolerated. Decreases in blood pressure are similar in patients treated with tezosentan or placebo. Moderate/severe liver impairment is associated with increased exposure to tezosentan, which is more pronounced in patients with elevated bilirubin levels, necessitating dose reduction.

The endothelin receptor antagonist tezosentan improves renal microcirculation in a porcine model of endotoxemic shock

BACKGROUND

Impaired renal microcirculation has been suggested as a factor contributing to the development of renal dysfunction in sepsis. This study was conducted to elucidate the role of endothelin-1 (ET-1)in mediating reductions in renal microcirculatory blood flow during endotoxemic shock.

METHODS

A prospective, randomized, and experimental study was performed with 16 anesthetized and mechanically ventilated pigs. After 2 h of lipopolysaccaride-induced endotoxemia, eight animals received a bolus dose of the dual endothelin receptor antagonist tezosentan (1 mg/kg), followed by a continuous infusion of 1 mg/kg/h throughout the experiment. Eight animals served as the control group. Renal microcirculation, total renal blood flow, plasma creatinine levels, cardiac index, and mean arterial pressure were measured. Plasma samples were collected for the measurement of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-10 (IL-10), ET-1, angiotensin II, and aldosterone.

RESULTS

Endotoxin infusion resulted in a state of circulatory shock with impairment of renal microcirculation. An increase in the plasma levels of TNF-alpha, IL-6, IL-10, ET-1, angiotensin II, and aldosterone was also observed. Tezosentan attenuated the decrease in renal microcirculation and renal blood flow, and attenuated the increase in plasma creatinine. Treatment with tezosentan did not significantly affect the plasma cytokine, angiotensin II, or aldosterone response to endotoxemia.

CONCLUSION

These results indicate that treatment with the dual endothelin receptor tezosentan in endotoxemic shock attenuates the reduction of renal microcirculation and total renal blood flow independently of plasma changes in the renin-angiotensin-aldosterone system or early plasma cytokine response.

Pathogenetic background for treatment of ascites and hepatorenal syndrome

Ascites and hepatorenal syndrome (HRS) are the major and challenging complications of cirrhosis and portal hypertension that significantly affect the course of the disease. Liver insufficiency, portal hypertension, arterial vasodilatation, and systemic cardiovascular dysfunction are major pathophysiological hallmarks. Modern treatment of ascites is based on this recognition and includes modest salt restriction and stepwise diuretic therapy with spironolactone and loop diuretics. Tense and refractory ascites should be treated with a large volume paracentesis, followed by volume expansion or transjugular intrahepatic portosystemic shunt. New treatment strategies include the use of vasopressin V(2)-receptor antagonists and vasoconstrictors. The HRS denotes a functional and reversible impairment of renal function in patients with severe cirrhosis with a poor prognosis. Attempts of treatment should seek to improve liver function, ameliorate arterial hypotension and central hypovolemia, and reduce renal vasoconstriction. Ample treatment of ascites and HRS is important to improve the quality of life and prevent further complications, but since treatment of fluid retention does not significantly improve survival, these patients should always be considered for liver transplantation.

Hepatorenal syndrome: current management

Hepatorenal syndrome (HRS) is a dreaded complication of advanced cirrhosis, with dismal prognosis if left untreated. Recent understanding of the pathophysiology underlying HRS development has led to many new treatments. Vasoconstrictors (eg, midodrine, terlipressin, or norepinephrine) together with albumin can improve the effective arterial blood volume with increased renal perfusion pressure. This combination has been proven successful in reversing HRS in approximately two thirds of patients. Transjugular intrahepatic portosystemic shunt (TIPS), which reduces portal pressure and decreases the sympathetic drive associated with portal hypertension, is effective in improving renal function. The combination of a TIPS and vasoconstrictor therapy has been shown to normalize renal function in a small number of patients. Liver transplantation corrects many of the pathophysiological abnormalities associated with HRS, and is the best treatment option. Patient outcome is improved further if the renal function is normalized prior to liver transplantation.

The hepatorenal syndrome

The onset of renal failure in a patient with cirrhosis or acute liver failure is alarming because it raises the possibility of the hepatorenal syndrome (HRS). Periodic surveillance of renal function is helpful in patients with severe liver disease to detect HRS early and to help correct reversible contributing factors. Once established, HRS responds relatively poorly to medical management, although recent advances have brought hope for an improved prognosis. In this article the diagnosis, pathophysiology, and management of HRS are discussed in detail, with an emphasis on recent diagnostic and therapeutic advances.

Pathogenesis and management of hepatorenal syndrome in patients with cirrhosis

Hepatorenal syndrome is a severe complication of advanced liver cirrhosis, in patients with ascites and marked circulatory dysfunction. It is clearly established that it has a functional nature, and that it is related to intense renal vasoconstriction. Despite its functional origin, the prognosis is very poor. In the present review, the most recent advances in diagnosis, pathophysiology, and treatment are discussed. Recent developments in pathophysiology are the basis of the new therapeutic strategies, which are currently under evaluation in randomised clinical trials.

Management of hepatorenal syndrome

Hepatorenal syndrome is a form of acute or sub-acute renal failure which develops in patients with chronic liver disease. In contrast to other forms of acute renal failure it may be reversible using pharmacological agents. The pathogenesis involves splanchnic vasodilatation and intense renal vasoconstriction. Increasing intravascular volume and prolonged treatment with vasoconstrictor drugs reverses renal failure in a significant proportion of patients. Agents currently used include the vasopressin analogues terlipressin and the alpha1-adrenoceptor agonist midodrine. The somatostatin analogue octreotide has been used in combination therapy but is ineffective as monotherapy. Intravenous albumin is an important adjunctive treatment both in the prevention and treatment of hepatorenal syndrome. Increasing intravascular volume using TIPS (transjugular intrahepatic stent shunt) is effective in some patients and may be useful in maintaining patients who have initially responded to pharmacological therapy. Despite improvements in survival, long term prognosis is still poor and generally depends on the degree of reversibility of the underlying liver disease or access to liver transplantation.

Significant improvement of portopulmonary hypertension after 1-week terlipressin treatment

Cirrhosis associated with moderate and severe portopulmonary hypertension carries a poor prognosis. Optimal management has not yet been defined. Current treatment options, such as prostacyclin analogues, endothelin antagonists, and phosphodiesterase-5 inhibitors, are characterized by slow onset of action and various adverse effects, particularly in patients with advanced cirrhosis. Here, we report the significant reduction of pulmonary arterial pressure after 1-week terlipressin treatment in a patient with concomitant hepato-renal syndrome. Terlipressin could be a novel and safe treatment for portopulmonary hypertension.