Incidence, Risk Factors, and Outcomes of Transition of Acute Kidney Injury to Chronic Kidney Disease in Cirrhosis: A Prospective Cohort Study

Renal Complications in Portal Hypertension

Acute kidney injury (AKI) is a common complication among patients with decompensated cirrhosis and its development is associated with worse prognosis in terms of survival. Patients with decompensated cirrhosis may develop a unique type of AKI, known as hepatorenal syndrome (HRS-AKI), characterized by marked impairment of kidney function due to haemodynamic changes that occur in late stages of liver cirrhosis. Besides, patients with cirrhosis also may develop chronic alterations of kidney function (chronic kidney disease, CKD), the incidence of which is increasing markedly and may be associated with clinical complications. The aim of this review is to provide the reader with an update of the most relevant aspects of alterations of kidney function in patients with cirrhossi that may be useful for theri clinical practice.

APASL clinical practice guidelines on the management of acute kidney injury in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a syndrome that is characterized by the rapid development of organ failures predisposing these patients to a high risk of short-term early death. The main causes of organ failure in these patients are bacterial infections and systemic inflammation, both of which can be severe. For the majority of these patients, a prompt liver transplant is still the only effective course of treatment. Kidneys are one of the most frequent extrahepatic organs that are affected in patients with ACLF, since acute kidney injury (AKI) is reported in 22.8-34% of patients with ACLF. Approach and management of kidney injury could improve overall outcomes in these patients. Importantly, patients with ACLF more frequently have stage 3 AKI with a low rate of response to the current treatment modalities. The objective of the present position paper is to critically review and analyze the published data on AKI in ACLF, evolve a consensus, and provide recommendations for early diagnosis, pathophysiology, prevention, and management of AKI in patients with ACLF. In the absence of direct evidence, we propose expert opinions for guidance in managing AKI in this very challenging group of patients and focus on areas of future research. This consensus will be of major importance to all hepatologists, liver transplant surgeons, and intensivists across the globe.

Applying Metabolomics and Aptamer-based Proteomics to Determine Pathophysiologic Differences in Decompensated Cirrhosis Patients Hospitalized with Acute Kidney Injury

A case-control study of 97 patients hospitalized at our institution. We performed aptamer-based proteomics and metabolomics on serum biospecimens obtained within 72 hours of admission. We compared the proteome and metabolome by the AKI phenotype (i.e., HRS-AKI, ATN) and by AKI recovery (decrease in sCr within 0.3 mg/dL of baseline) using ANCOVA analyses adjusting for demographics and clinical characteristics. We completed Random Forest (RF) analyses to identify metabolites and proteins associated with AKI phenotype and recovery. Lasso regression models were developed to highlight metabolites and proteins could improve diagnostic accuracy. Results: ANCOVA analyses showed no metabolomic or proteomic differences by AKI phenotype while identifying differences by AKI recovery status. Our RF and Lasso analyses showed that metabolomics can improve the diagnostic accuracy of both AKI diagnosis and recovery, and aptamer-based proteomics can enhance the diagnostic accuracy of AKI recovery. Discussion: Our analyses provide novel insight into pathophysiologic pathways, highlighting the metabolomic and proteomic similarities between patients with cirrhosis with HRS-AKI and ATN while also identifying differences between those with and without AKI recovery.

Regulation of regulated cell death by extracellular vesicles in acute kidney injury and chronic kidney disease

The imbalance between proliferation and death of kidney resident cells is a crucial factor in the development of acute or chronic renal dysfunction. Acute kidney injury (AKI) is often associated with the rapid loss of tubular epithelial cells (TECs). Sustained injury leads to the loss of glomerular endothelial cells (GECs) and podocytes, which is a key mechanism in the pathogenesis of glomerular diseases. This irreversible damage resulting from progressive cell loss eventually leads to deterioration of renal function characterized by glomerular compensatory hypertrophy, tubular degeneration, and renal fibrosis. Regulated cell death (RCD), which involves a cascade of gene expression events with tight structures, plays a certain role in regulating kidney health by determining the fate of kidney resident cells. Under pathological conditions, cells in the nephron have been demonstrated to constitutively release extracellular vesicles (EVs) which act as messengers that specifically interact with recipient cells to regulate their cell death process. For therapeutic intervention, exogenous EVs have exhibited great potential for the prevention and treatment of kidney disease by modulating RCD, with enhanced effects through engineering modification. Based on the functional role of EVs, this review comprehensively explores the regulation of RCD by EVs in AKI and chronic kidney disease (CKD), with emphasis on pathogenesis and therapeutic intervention.

Acute-on-chronic liver failure - steps towards harmonization of the definition!

Acute-on-chronic liver failure (ACLF), usually precipitated by alcohol misuse or viral reactivation, is characterised by rapid onset and usually reversible liver failure. Various definitions of ACLF have been proposed and widely used across the globe, including those by APASL, COSSH, EASL-CLIF, Japanese experts, and NACSELD. Although all the definitions have several similarities and connote high short-term mortality, a clear and standardised definition is still lacking, hampering research in this key area. In this review, we discuss the similarities and differences among various definitions and propose steps to harmonise EASL-CLIF, APASL, NACSELD, Japanese, and Chinese definitions of ACLF.

Noninferiority Outcomes of Besifovir Compared to Tenofovir Alafenamide in Treatment-Naïve Patients with Chronic Hepatitis B

Background/Aims

: Besifovir dipivoxil maleate (BSV) and tenofovir alafenamide fumarate (TAF) have been recently approved in Korea as the initial antiviral agents for chronic hepatitis B (CHB). However, the real-world outcome data for these drugs remain limited. Therefore, we conducted a noninferiority analysis using real-world data to compare the clinical outcomes of the two nucleotide analogs in treatment-naïve patients with CHB.

Methods

: We retrospectively investigated a cohort of patients with CHB who received BSV or TAF as first-line antiviral agents. The endpoints were virological response (VR) and liver-related clinical outcomes.

Results

: A total of 537 patients, consisting of 202 and 335 patients administered BSV and TAF, respectively, were followed up for 42 months. No significant difference was observed between the VRs of the patients from the two groups. The rates of biochemical response, virologic breakthrough, and incidence rates of hepatocellular carcinoma did not differ between the groups. However, the hepatitis B e antigen seroclearance rate was higher and the renal function declined less in the BSV group. Multivariable analysis indicated older age, alcohol abuse, cirrhosis and ascites, and lower serum HBV DNA level to be independently associated with increased hepatocellular carcinoma risk. The 1:1 propensity score-matched analysis with 400 patients showed VR rates of 85.0% and 88.7% in the BSV and TAF group patients, respectively, at 2 years. The absolute value of the 95% confidence interval for the difference (-0.04 to 0.12) satisfied the a priori limit of a noninferiority of 0.15.

Conclusions

: BSV is noninferior to TAF in terms of VR, and their clinical outcomes are comparable to CHB.

Cholemic Nephropathy: Role in Acute Kidney Injury in Cholestasis and Cirrhosis

The concept of structural kidney damage and renal dysfunction as a result of jaundice attracted attention in the medical community in the early and mid-20th century. The postulated doctrine of the time was that the excretion of elevated concentrations of bile results in bile-stained casts occupying collecting and distal convoluted tubules, degeneration of tubular epithelium, and decreased renal function. Compared to the hepatorenal syndrome, the poster child of hepatology and nephrology collaboration, the notion of structural kidney damage and renal dysfunction as a result of cholemia lost its traction and has almost disappeared from modern textbooks. Today, cholemic nephropathy is experiencing a renaissance, with multiple case reports and case series of jaundiced patients with kidney dysfunction and evidence of bile acid casts upon histologic examination. Published cases include acute hepatitis, chronic liver injury, cirrhosis, and obstructive etiologies. Diagnosis of cholemic nephropathy is based on histological examination, typically showing intraluminal bile casts predominantly located in the distal tubules. In common bile duct-ligated mice, the histomorphological and functional alterations of cholemic nephropathy mimic those seen in humans. Some argue against the concept of cholemic nephropathy and postulate that bile casts are a secondary phenomenon. What we need are carefully designed trials to establish diagnostic criteria and subsequently translate this knowledge into evidence-based therapies.

Evaluation of Kidney Injury Using Arterial Spin Labeling and Blood Oxygen Level-Dependent MRI: An Experimental Study in Rats With Carbon Tetrachloride-Induced Liver Cirrhosis

BACKGROUND

Serum creatinine (Scr) may be not suited to timely and accurately reflect kidney injury related to chronic liver disease. Currently, the ability of arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) sequences to evaluate renal blood flow (RBF) and blood oxygen in chronic liver disease remains to be verified.

PURPOSE

To investigate the value of ASL and BOLD imaging in evaluating hemodynamics and oxygenation changes during kidney injury in an animal model of chronic liver disease.

STUDY TYPE

Prospective.

ANIMAL MODEL

Chronic liver disease model was established by subcutaneous injection of carbon tetrachloride. Forty-three male Sprague-Dawley rats (8 weeks) were divided into a pathological group (0, 2, 4, 6, 8, 12 weeks, each group: N = 6) and a continuous-scanning group (N = 7).

FIELD STRENGTH/SEQUENCE

3-T, ASL, BOLD, and T2W.

ASSESSMENT

Regions of interest in the cortex (CO), outer stripe of the outer medulla (OSOM), and inner stripe of the outer medulla (ISOM) are manually delineated. The RBF and T2* values at each time point (0, 2, 4, 6, 8, 12 weeks) are measured and compared. Hematoxylin-eosin score (HE Score, damage area scoring method), alpha-smooth muscle actin (α-SMA), hypoxia-inducible factor-1alpha (HIF-1α), peritubular capillar (PTC) density, Scr, and neutrophil gelatinase-associated lipocalin were harvested.

STATISTICAL TESTS

Analysis of variance, Spearman correlation analysis, Kruskal-Wallis tests, and receiver operating characteristic analysis with the area under the curve (AUC). A P-value <0.05 was considered statistically significant.

RESULTS

Renal RBF and T2* values of CO, OSOM, and ISOM were significantly different from baseline. Both RBF and T2* were significantly correlated with HE Score, α-SMA, HIF-1α, and PTC density (|r| = 0.406-0.853). RBF demonstrated superior diagnostic capability in identifying severe kidney injury in this model of chronic liver disease (AUC = 0.964).

DATA CONCLUSION

Imaging by ASL and BOLD may detect renal hemodynamics and oxygenation changes related to chronic liver disease early.

EVIDENCE LEVEL

5 TECHNICAL EFFICACY: Stage 2.

Pharmacokinetics and Tolerability of Zibotentan in Patients with Concurrent Moderate Renal and Moderate Hepatic Impairment

BACKGROUND AND OBJECTIVE

Zibotentan, a selective endothelin A receptor antagonist, is in development for chronic liver and kidney disease. The pharmacokinetics (PK) of zibotentan were previously investigated in patients with either renal impairment or hepatic impairment, but the impact of both pathologies on PK was not evaluated. This study evaluated the PK and tolerability of a single oral dose of zibotentan in participants with concurrent moderate renal impairment and moderate hepatic impairment versus control participants.

METHODS

Twelve participants with moderate renal and hepatic impairment and 11 healthy matched control participants with no clinically significant liver or kidney disease were enrolled in an open-label, parallel-group study design. After administration of a single oral dose of zibotentan 5 mg, blood and urine sampling was performed. Pharmacokinetic parameters were determined for each of the two cohorts and compared. Comparisons between the cohorts were based on the geometric least squares mean ratio for the primary endpoints, which were area under the plasma concentration-time curve (AUC) from time zero to infinity (AUC∞) and from time zero to the time of the last measurable concentration (AUClast), and maximum plasma drug concentration (Cmax) on Day 1 through 120 h post-dose. Secondary endpoints included apparent total body clearance (CL/F) on Day 1 through 120 h post-dose. Safety endpoints were assessed up to discharge.

RESULTS

In total, 11 participants with concurrent moderate renal and hepatic impairment, and 11 controls, completed the study. Zibotentan was generally well tolerated, and no new clinically significant safety findings were observed. Total exposure (AUC∞ and AUClast) was approximately 2.10-fold higher in participants with concurrent moderate renal and hepatic impairment versus controls, while Cmax and total nonrenal body clearance were similar among all groups. A regression-based post hoc analysis, comparing exposure and CL/F in patients with concurrent impairment to patients with either renal or hepatic impairment alone, showed that CL/F with concurrent impairment was approximately half of that in controls and was positively correlated with reduction of renal function. Inclusion of the data on concurrent moderate renal and hepatic impairment in the regression analysis led to a narrower confidence interval for the predicted mean CL/F in participants with moderate hepatic impairment.

CONCLUSION

The presented findings advance the understanding of the PK of zibotentan in both renal impairment and hepatic impairment, with and without overlapping pathologies, and will thus increase the confidence of dose selection in future studies, particularly in vulnerable patient populations with concurrent renal and hepatic impairment.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05112419.

Non-resolution of acute kidney injury in the first week portends the development of chronic kidney disease in critically ill patients with cirrhosis

BACKGROUND

Renal tubular epithelial cells (RTECs) cause maladaptive repair and perpetuate renal fibrosis.

AIM

To evaluate urinary neutrophil gelatinase-associated lipocalin (NGAL) and RTEC as risk factors for non-resolution of acute kidney injury (AKI-NR) at day seven and chronic kidney disease (CKD) in critically ill patients with cirrhosis.

METHODS

We performed urinary NGAL and microscopy at enrolment and day 7 in all patients. We assessed 17 renal injury, endothelial injury and repair markers, genes for mitochondrial biogenesis by qRT-PCR in RTEC, and post-mortem renal biopsies for understanding mechanisms of AKI non-resolution (n = 30).

RESULTS

We enrolled 310 patients, aged 48.1 ± 11.6 years, 87% male, 90% alcoholic. Of these, 36% had RTEC at enrolment, and 53% had AKI-NR on day 7. On mean follow-up of 136 days (range 43-365), 150 (48.3%) developed CKD. The presence of RTEC or granular casts, NGAL and AKI-NR were independent predictors of CKD development on competing risk analysis. Higher MCP-1, renal endothelial injury, decrease in tubular repair markers and failure of mitochondrial biogenesis in RTEC were seen in patients with AKI-NR compared with AKI-R (p < 0.05). Renal biopsies showed infiltration with monocyte-macrophage, increased α-SMA, and tubulointerstitial fibrosis.

CONCLUSION

Almost two-thirds of critically ill patients with cirrhosis have AKI, which resolves in only one-half at day seven and predicts the development of CKD. Higher NGAL, RTEC, or granular casts were independent predictors of AKI-NR and CKD development. Enhanced tubular and endothelial injury, decreased repair, monocyte-macrophage infiltration and mitochondrial dysfunction in RTEC are associated with AKI non-resolution and risk of renal fibrosis.

Terlipressin in the management of adults with hepatorenal syndrome-acute kidney injury (HRS-AKI)

INTRODUCTION

Kidney is the most common extra-hepatic organ involved in patients with advanced liver cirrhosis and acute-on-chronic liver failure. Hepatorenal syndrome-acute kidney injury (HRS-AKI) accounts for most hospitalizations, and liver transplantation (LT) remains the ultimate and long-term treatment in such patients. However, HRS-AKI, being a functional renal failure, has a fair chance of reversal, and as such, patients who achieve reversal of HRS-AKI have better outcomes post-LT.

AREAS COVERED

In this review, we discuss the pharmacokinetics, pharmacodynamics and evidence to support the use of terlipressin in HRS-AKI while we also address predictors of response and the associated adverse events. Further, we discuss the role of terlipressin in the context of LT.

EXPERT OPINION

The recommended treatment for HRS-AKI reversal includes a vasoconstrictor in addition to volume expansion with albumin. The three vasoconstrictor regimens generally used to treat HRS-AKI include octreotide plus midodrine, noradrenaline, and terlipressin. Of these, terlipressin is a widely used drug and has been recently approved by US Food and Drug Administration (USFDA) for HRS-AKI. Terlipressin is the most effective drug for HRS-AKI reversal and is associated with a decreased need for renal replacement therapy pre- and post-transplant. Furthermore, terlipressin responders have improved transplant-free and post-transplant survival.

Pathophysiology and management of liver cirrhosis: from portal hypertension to acute-on-chronic liver failure

Cirrhosis transcends various progressive stages from compensation to decompensation driven by the severity of portal hypertension. The downstream effect of increasing portal hypertension severity leads to various pathophysiological pathways, which result in the cardinal complications of cirrhosis, including ascites, variceal hemorrhage, and hepatic encephalopathy. Additionally, the severity of portal hypertension is the central driver for further advanced complications of hyperdynamic circulation, hepatorenal syndrome, and cirrhotic cardiomyopathy. The management of these individual complications has specific nuances which have undergone significant developments. In contrast to the classical natural history of cirrhosis and its complications which follows an insidious trajectory, acute-on-chronic failure (ACLF) leads to a rapidly downhill course with high short-term mortality unless intervened at the early stages. The management of ACLF involves specific interventions, which have quickly evolved in recent years. In this review, we focus on complications of portal hypertension and delve into an approach toward ACLF.

Longer time to recovery from acute kidney injury is associated with major adverse kidney events in patients with cirrhosis

BACKGROUND

In patients with cirrhosis and acute kidney injury (AKI), longer time to AKI-recovery may increase the risk of subsequent major-adverse-kidney-events (MAKE).

AIMS

To examine the association between timing of AKI-recovery and risk of MAKE in patients with cirrhosis.

METHODS

Hospitalised patients with cirrhosis and AKI (n = 5937) in a nationwide database were assessed for time to AKI-recovery and followed for 180-days. Timing of AKI-recovery (return of serum creatinine <0.3 mg/dL of baseline) from AKI-onset was grouped by Acute-Disease-Quality-Initiative Renal Recovery consensus: 0-2, 3-7, and >7-days. Primary outcome was MAKE at 90-180-days. MAKE is an accepted clinical endpoint in AKI and defined as the composite outcome of ≥25% decline in estimated-glomerular-filtration-rate (eGFR) compared with baseline with the development of de-novo chronic-kidney-disease (CKD) stage ≥3 or CKD progression (≥50% reduction in eGFR compared with baseline) or new haemodialysis or death. Landmark competing-risk multivariable analysis was performed to determine the independent association between timing of AKI-recovery and risk of MAKE.

RESULTS

4655 (75%) achieved AKI-recovery: 0-2 (60%), 3-7 (31%), and >7-days (9%). Cumulative-incidence of MAKE was 15%, 20%, and 29% for 0-2, 3-7, >7-days recovery groups, respectively. On adjusted multivariable competing-risk analysis, compared to 0-2-days, recovery at 3-7 and >7-days was independently associated with an increased risk for MAKE: sHR 1.45 (95% CI 1.01-2.09, p = 0.042), sHR 2.33 (95% CI 1.40-3.90, p = 0.001), respectively.

CONCLUSION

Longer time to recovery is associated with an increased risk of MAKE in patients with cirrhosis and AKI. Further research should examine interventions to shorten AKI-recovery time and its impact on subsequent outcomes.

Liver transplantation in Acute-on-Chronic liver failure: Timing of transplantation and selection of patient population

Acute-on-Chronic liver failure (ACLF) is a clinical syndrome with high short-term mortality. Alcoholic ACLF is prevalent in European and American countries, while hepatitis B virus (HBV)-related ACLF is more common in the Asia-Pacific region. There is still a lack of a unified definition standard for ACLF, due to various etiologies and pathogeneses in different continents. Currently, liver transplantation (LT) is the most effective treatment for liver failure. However, the shortage of liver sources is still a global problem, which seriously limits the clinical application of an LT. Premature LT aggravates the shortage of liver resources to a certain extent, and too much delay significantly increases the risk of complications and death. Therefore, this study reviews the current literature on LT in the treatment of ACLF and discusses further the challenges for ACLF patients, the timing of LT for ACLF, and the choice of the patient population.

AGA Clinical Practice Update on the Evaluation and Management of Acute Kidney Injury in Patients With Cirrhosis: Expert Review

DESCRIPTION

The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update is to review the available published evidence and expert advice regarding the clinical management of patients with suspected acute kidney injury in patients with cirrhosis.

METHODS

This article provides practical advice for the management of patients with cirrhosis and acute kidney injury based on the best available published evidence. This best practice document is not based on a formal systematic review. This expert review was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through the standard procedures of Clinical Gastroenterology & Hepatology. These Best Practice Advice (BPA) statements were drawn from a review of the published literature and from expert opinion. Since systematic reviews were not performed, these BPA statements do not carry formal ratings of the quality of evidence or strength of the presented considerations. BEST PRACTICE ADVICE 1: Acute kidney injury (AKI) should be diagnosed when the serum creatinine increases by ≥0.3 mg/dL within 48 hours or is ≥50% from baseline or when the urine output is reduced below 0.5 mL/kg/h for >6 hours. BEST PRACTICE ADVICE 2: Preventive measures against the development of AKI in cirrhosis include (1) avoidance of potentially nephrotoxic medications like nonsteroidal anti-inflammatory drugs (NSAIDs), (2) avoidance of excessive or unmonitored diuretics or nonselective beta-blockade, (3) avoidance of large-volume paracentesis without albumin replacement, and (4) counseling patients to avoid alcohol use. BEST PRACTICE ADVICE 3: (A) Investigation is directed to determining the cause of AKI, which can be due to hypovolemic causes (volume responsive, and the most common cause of AKI in patients with cirrhosis); acute tubular necrosis; hepatorenal syndrome with AKI (HRS-AKI) (a functional renal failure that persists despite volume repletion); HRS with acute kidney disease, a type of functional renal failure of <3 months- duration in which criteria for HRS-AKI are not met; or postrenal, which occurs only rarely. (B) The specific type of AKI should be identified through a careful history, physical examination, blood biochemistry, urine microscopic examination, urine chemistry (Na+ and urea) and selected urinary biomarkers, and renal ultrasound. BEST PRACTICE ADVICE 4: A rigorous search for infection is required in all patients with AKI. A diagnostic paracentesis should be carried out to evaluate for spontaneous bacterial peritonitis; blood and urine cultures and chest radiograph are also required. There is no role for routine prophylactic antibiotics in patients with AKI, but broad-spectrum antibiotics should be started whenever infection is strongly suspected. BEST PRACTICE ADVICE 5: When AKI is diagnosed, diuretics and nonselective beta-blockers should be held, NSAIDs discontinued, the precipitating cause of AKI treated, and fluid losses replaced, administering albumin 1 g/kg/d for 2 days if the serum creatinine shows doubling from baseline. Urine output, vital signs, and when indicated, echocardiography or CVP (if there is a pre-existing central line) should be used to monitor fluid status. BEST PRACTICE ADVICE 6: When the serum creatinine remains higher than twice the baseline value despite these measures, treatment of HRS-AKI should be initiated with albumin at a dose of 1 g/kg intravenously on day 1 followed by 20-40 g daily along with vasoactive agents (terlipressin; if terlipressin is not available, either a combination of octreotide and midodrine; or norepinephrine, depending on institutional preferences) and continued either until 24 hours following the return of the serum creatinine level to within ≤0.3 mg/dL of baseline for 2 consecutive days or for a total of 14 days of therapy. BEST PRACTICE ADVICE 7: Terlipressin should be initiated as a bolus dose of 1 mg every 4-6 hours (total 4-6 mg/d). The dose should be increased to a maximum of 2 mg every 4-6 hours (total 8-12 mg/d) if there is no reduction in serum creatinine at day 3 of therapy by at least 25% compared to the baseline value. Alternatively, clinicians can administer terlipressin by continuous intravenous infusion at a lower starting dose of 2 mg/d, which may reduce ischemic side effects and increase the dose gradually every 24-48 hours up to a maximum dose of 12 mg/d, or reversal of HRS. As per Food and Drug Administration restrictions, terlipressin should not be used in patients with a serum creatinine ≥5 mg/dL, or oxygen saturation of <90%. BEST PRACTICE ADVICE 8: Oral midodrine when used should be initiated at doses of 7.5 mg and titrated upward to 12.5 mg 3 times daily with octreotide (starting with 100 μg and titrating upward to 200 μg subcutaneously 3 times daily). BEST PRACTICE ADVICE 9: Norepinephrine should be used as a continuous intravenous infusion at a starting dose of 0.5 mg/h and the dose increased every 4 hours by 0.5 mg/h to a maximum of 3 mg/h with the goal of increasing the mean arterial pressure by ≥10 mm Hg and/or the urine output to >50 mL/h for at least 4 hours. BEST PRACTICE ADVICE 10: The risks of ischemic side effects of terlipressin and norepinephrine include angina and ischemia of fingers, skin, and intestine. These side effects may be lowered by starting at the lowest dose and gradually titrating upward. BEST PRACTICE ADVICE 11: Fluid status should be closely monitored because of the risk of pulmonary edema with excessive use of albumin. BEST PRACTICE ADVICE 12: Renal replacement therapy (RRT) may be used in the management of (A) AKI secondary to acute tubular necrosis; (B) HRS-AKI in potential candidates for liver transplantation (that is, RRT should not be used in patients with HRS-AKI who are not candidates for liver transplantation); and (C) AKI of uncertain etiology in which the need for RRT may be considered on an individual basis. BEST PRACTICE ADVICE 13: Transjugular intrahepatic portosystemic shunts should not be used as a specific treatment of HRS-AKI. BEST PRACTICE ADVICE 14: Liver transplantation is the most effective treatment for HRS-AKI. Pharmacotherapy for HRS-AKI before proceeding with liver transplantation may be associated with better post-liver transplantation outcomes. Selected patients with HRS-AKI may require simultaneous liver kidney transplantation based on updated Organ Procurement and Transplantation Network listing criteria.

Novel Biomarkers of AKI in Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis that is associated with poor outcomes and decreased survival. The definition of AKI in cirrhosis is currently based on changes of serum creatinine levels with respect to baseline values. Differential diagnosis of the causes of AKI is of major relevance, considering that some causes of AKI, such as hepatorenal syndrome, have specific treatment options and different prognosis. Prediction of kidney function recovery and patients' survival is also crucial in this patient population to guide clinical decisions. AKI biomarkers in cirrhosis have emerged as a promising tool for differential diagnosis and prognosis in this situation. There are consistent data showing that some urine biomarkers, particularly neutrophil gelatinase-associated lipocalin, may be useful in daily clinical practice for the differential diagnosis of the cause of AKI in cirrhosis. AKI biomarkers may constitute a useful tool for use in differential diagnosis, prognosis of renal function, and survival in patients with cirrhosis. This review focuses on the current state of knowledge and future perspective of novel biomarkers of AKI in cirrhosis.

Cellular senescence in ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury, a main reason of mortality and morbidity worldwide, occurs in many organs and tissues. As a result of IR injury, senescent cells can accumulate in multiple organs. Increasing evidence shows that cellular senescence is the underlying mechanism that transforms an acute organ injury into a chronic one. Several recent studies suggest senescent cells can be targeted for the prevention or elimination of acute and chronic organ injury induced by IR. In this review, we concisely introduce the underlying mechanism and the pivotal role of premature senescence in the transition from acute to chronic IR injuries. Special focus is laid on recent advances in the mechanisms as well as on the basic and clinical research, targeting cellular senescence in multi-organ IR injuries. Besides, the potential directions in this field are discussed in the end. Together, the recent advances reviewed here will act as a comprehensive overview of the roles of cellular senescence in IR injury, which could be of great significance for the design of related studies, or as a guide for potential therapeutic target.

Sarcopenia HIBA score predicts sarcopenia and mortality in patients on the liver transplant waiting list

Sarcopenia is a prevalent condition that predicts prognosis in patients awaiting liver transplantation (LT). The gold standard for the diagnosis of sarcopenia is the assessment of the muscular area at L3 with computed tomography (CT) scan (skeletal muscle index [SMI]), but the routine use of CT scan is limited in clinical practice. Thus, we designed a single-center observational study aimed to evaluate the clinical factors associated with the presence of sarcopenia by SMI, and to build a score capable of predicting or excluding the presence of sarcopenia in patients on the LT waiting list (WL). Binary logistic regression analysis was performed to establish the factors independently associated with sarcopenia, and the Sarcopenia Hospital Italiano de Buenos Aires (HIBA) score was built from the resulting model after internal validation analysis by bootstrapping and correction for optimism. The predictive capability of mortality on the WL was evaluated with competing risk regression analysis. A total of 215 patients with cirrhosis on the LT WL were included. The independent factors associated with the presence of sarcopenia were male sex (odds ratio [OR]: 6.09, p < 0.001), body mass index (OR: 0.74, p < 0.001), Child Pugh (OR: 1.44, p < 0.001), and the ratio creatinine/Cystatin C (OR: 0.03, p = 0.007). The Sarcopenia HIBA score constructed with these variables showed an area under the curve of 0.862. During follow-up, 77 (36%) patients underwent LT, 46 (21%) died, and 92 (43%) remained alive. After adjusting for Model for End-Stage Liver Disease-Sodium, Sarcopenia HIBA score was an independent predictor of WL mortality (subhazard ratio: 1.19; 95% confidence interval 1.01-1.40; p = 0.042). Sarcopenia HIBA score is an easy-to-use, objective, and reliable diagnostic and predictive tool that can be useful to improve the prognostic evaluation and allow identifying a group of patients with a higher risk of death while awaiting LT.

Acute kidney disease is common and associated with poor outcomes in patients with cirrhosis and acute kidney injury

BACKGROUND & AIMS

Acute kidney disease (AKD) is the persistence of acute kidney injury (AKI) for up to 3 months, which is proposed to be the time-window where critical interventions can be initiated to alter downstream outcomes of AKI. In cirrhosis, AKD and its impact on outcomes have been scantly investigated. We aimed to define the incidence and outcomes associated with AKD in a nationwide US cohort of hospitalized patients with cirrhosis and AKI.

METHODS

Hospitalized patients with cirrhosis and AKI in the Cerner-Health-Facts database from 1/2009-09/2017 (n = 6,250) were assessed for AKD and were followed-up for 180 days. AKI and AKD were defined based on KDIGO and ADQI AKD and renal recovery consensus criteria, respectively. The primary outcome measure was mortality, and the secondary outcome measure was de novo chronic kidney disease (CKD). Competing-risk multivariable models were used to determine the independent association of AKD with primary and secondary outcomes.

RESULTS

AKD developed in 32% of our cohort. On multivariable competing-risk analysis adjusting for significant confounders, patients with AKD had higher risk of mortality at 90 (subdistribution hazard ratio [sHR] 1.37; 95% CI 1.14-1.66; p = 0.001) and 180 (sHR 1.37; 95% CI 1.14-1.64; p = 0.001) days. The incidence of de novo CKD was 37.5%: patients with AKD had higher rates of de novo CKD (64.0%) compared to patients without AKD (30.7%; p <0.001). After adjusting for confounders, AKD was independently associated with de novo CKD (sHR 2.52; 95% CI 2.01-3.15; p <0.001) on multivariable competing-risk analysis.

CONCLUSIONS

AKD develops in 1 in 3 hospitalized patients with cirrhosis and AKI and it is associated with worse survival and de novo CKD. Interventions that target AKD may improve outcomes of patients with cirrhosis and AKI.

LAY SUMMARY

In a nationwide US cohort of hospitalized patients with cirrhosis and acute kidney injury, acute kidney disease developed in 1 in 3 patients and was associated with worse survival and chronic kidney disease. Interventions that target acute kidney disease may improve outcomes of patients with cirrhosis and acute kidney injury.

Hepatorenal Syndrome: Pathophysiology

Hepatorenal syndrome (HRS) is defined as a functional renal failure without major histologic changes in individuals with severe liver disease and it is associated with a high mortality rate. Renal hypoperfusion due to marked vasoconstriction as a result of complex circulatory dysfunction has been suggested to be the cornerstone of HRS. Splanchnic and peripheral arterial vasodilation and cirrhotic cardiomyopathy result in effective arterial hypovolemia and compensatory activation of vasoconstrictor mechanisms. The efficacy of current therapeutic strategies targeting this circulatory dysfunction is limited. Increasing evidence suggests a substantial role of systemic inflammation in HRS via either vascular or direct renal effects. Here we summarize the current understanding of HRS pathophysiology.

Race Adjustment in eGFR Equations Does Not Improve Estimation of Acute Kidney Injury Events in Patients with Cirrhosis

BACKGROUND

Accuracy of glomerular filtration rate estimating (eGFR) equations has significant implications in cirrhosis, potentially guiding simultaneous liver kidney allocation and drug dosing. Most equations adjust for Black race, partially accounted for by reported differences in muscle mass by race. Patients with cirrhosis, however, are prone to sarcopenia which may mitigate such differences. We evaluated the association between baseline eGFR and incident acute kidney injury (AKI) in patients with cirrhosis with and without race adjustment.

METHODS

We conducted a retrospective national cohort study of veterans with cirrhosis. Baseline eGFR was calculated using multiple eGFR equations including Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), both with and without race adjustment. Poisson regression was used to investigate the association between baseline eGFR and incident AKI events per International Club of Ascites criteria.

RESULTS

We identified 72,267 patients with cirrhosis, who were 97.3% male, 57.8% white, and 19.7% Black. Over median follow-up 2.78 years (interquartile range 1.22-5.16), lower baseline eGFR by CKD-EPI was significantly associated with higher rates of AKI in adjusted models. For all equations this association was minimally impacted when race adjustment was removed. For example, removal of race adjustment from CKD-EPI resulted in a 0.1% increase in the association between lower eGFR and higher rate of AKI events per 15 mL/min/1.73 m² change (p < 0.001).

CONCLUSIONS

Race adjustment in eGFR equations did not enhance AKI risk estimation in patients with cirrhosis. Further study is warranted to assess the impacts of removing race from eGFR equations on clinical outcomes and policy.

Acute-on-Chronic Liver Failure Clinical Guidelines

In patients with cirrhosis and chronic liver disease, acute-on-chronic liver failure is emerging as a major cause of mortality. These guidelines indicate the preferred approach to the management of patients with acute-on-chronic liver failure and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence for these guidelines was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation process. In instances where the evidence was not appropriate for Grading of Recommendations, Assessment, Development, and Evaluation, but there was consensus of significant clinical merit, key concept statements were developed using expert consensus. These guidelines are meant to be broadly applicable and should be viewed as the preferred, but not only, approach to clinical scenarios.

Management of Portal Hypertension

Portal hypertension is the cause of the clinical complications associated with cirrhosis. The primary complications of portal hypertension are ascites, acute variceal bleed, and hepatic encephalopathy. Hepatic venous pressure gradient measurement remains the gold standard test for diagnosing cirrhosis-related portal hypertension. Hepatic venous pressure gradient more than 10 mmHg is associated with an increased risk of complications and is termed clinically significant portal hypertension (CSPH). Clinical, laboratory, and imaging methods can also aid in diagnosing CSPH non-invasively. Recently, deep learning methods have been demonstrated to diagnose CSPH effectively. The management of portal hypertension is always individualized and is dependent on the etiology, the availability of therapies, and the degree of portal hypertension complications. In this review, we discuss the diagnosis and management of cirrhosis-related portal hypertension in detail. Also, we highlight the history of portal hypertension and future research areas in portal hypertension.

Diffusion kurtosis imaging and arterial spin labeling for the noninvasive evaluation of persistent post-contrast acute kidney injury

OBJECTIVE

We investigated whether diffusion kurtosis imaging (DKI) and arterial spin labeling (ASL) facilitated the assessment of serial alterations in persistent post-contrast acute kidney injury (PC-AKI).

MATERIALS AND METHODS

We randomly divided 24 rats into four PC-AKI groups (days 1, 3, 7, and 13, n = 6/group), with an additional six control animals. We conducted functional magnetic resonance imaging (MRI), diffusion kurtosis imaging (DKI), and arterial spin-labeling (ASL) analyses. Mean kurtosis (MK), axial kurtosis (Ka), mean diffusivity (MD), fractional anisotropy (FA), radial kurtosis (Kr), and renal blood flow (RBF) maps were normalized to baseline (prior to contrast injection) to calculate adjusted △RBF, △MK, △Ka, △MD, △FA, and △Kr values. We also investigated urinary neutrophil gelatinase associated lipocalin (NGAL), serum cystatin C (CysC), aquaporin-2 (AQP2), hypoxia-inducible factor-1 (HIF-1α), and histological indices.

RESULTS

In the inner stripe of the outer medulla, when compared with controls, decreased △FA and △MD levels were observed on days 1, 3, and 7, and a distinct elevation in △MK and △Kr on days 1-13, and a persistent decrease in △RBF on days 1-13, and a prominent increase in △Ka on days 7 and 13 in PC-AKI animals (all p < 0.05). △Ka and △MK were positively correlated with AQP-2 (r = 0.8086, p < 0.0001 and r = 0.7314, p < 0.0001, respectively), and △RBF was highly correlated with HIF-1α (r = -0.7592, p < 0.0001). Moreover, both CysC and NGAL were significantly elevated in PC-AKI animals when compared with controls from days 1-13 (all p < 0.05). Renal histological data indicated severe tubular and glomerular injury at days 1-13 in all PC-AKI groups.

CONCLUSION

ASL and DKI may be noninvasively and longitudinally used to detect PC-AKI and predict further outcomes.

Cholemic Nephropathy as Cause of Acute and Chronic Kidney Disease. Update on an Under-Diagnosed Disease

Cholemic nephropathy (CN) is a recognized cause of acute kidney injury (AKI) in patients with severe hyperbilirubinemia (sHyb) and jaundice. Pathophysiological mechanisms of CN are not completely understood, but it seems caused both by direct toxicity of cholephiles and bile casts formation in nephrons enhanced by prolonged exposure to sHyb, particularly in the presence of promoting factors, as highlighted by a literature reviewed and by personal experience. The aim of our update is to retrace CN in its pathophysiology, risk factors, diagnosis and treatment, underlining the role of sHyb, promoting factors, and CN-AKI diagnostic criteria in the different clinical settings associated with this often-concealed disease. Our purpose is to focus on clinical manifestation of CN, exploring the possible transition to CKD. Cholemic nephropathy is an overlooked clinical entity that enters differential diagnosis with other causes of AKI. Early diagnosis and treatment are essential because renal injury could be fully reversible as rapidly as bilirubin levels are reduced. In conclusion, our proposal is to introduce an alert for considering CN in diagnostic and prognostic scores that include bilirubin and/or creatinine with acute renal involvement, with the aim of early diagnosis and treatment of sHyb to reduce the burden on renal outcome.

Cystatin C: best biomarker for acute kidney injury and estimation of glomerular filtration rate in childhood cirrhosis

The objective of the study was to evaluate the diagnostic and prognostic role of serum cystatin C, urinary neutrophil gelatinase-associated lipocalin (NGAL), and renal resistive index (RRI) in AKI among pediatric cirrhotics. The study included cirrhotic children under 18 years of age. AKI was diagnosed as per Kidney Diseases-Improving Global Outcomes (KDIGO) guidelines. All patients underwent measurement of serum cystatin C, urinary NGAL, and RRI at baseline, 3 months, and 6 months. eGFR was calculated using both creatinine- and cystatin-based equations. Of the 247 cirrhotics admitted during the study, 100 gave consent and were included. Forty-one fulfilled the KDIGO definition of AKI of whom 22 showed resolution. Two of these children had a repeat AKI at 2 and 4 months after initial AKI; both resolved with medical management. On logistic regression analysis, serum cystatin C (OR: 544.8, 95% CI: 24.4-12170, p < 0.0005) and urinary NGAL (OR: 1.006, 95% CI: 1001-1.012, p = 0.019) were found to be significantly associated with AKI. Cystatin C alone was the best biomarker for diagnosing AKI in children with decompensation (OR: 486.7, p < 0.0005) or spontaneous bacterial peritonitis (p = 0.02). eGFR calculated by serum cystatin C-based formulas was more reliable than that calculated by creatinine-based equations.Conclusion: Serum cystatin C is the best biomarker for diagnosis of AKI in pediatric cirrhotics, especially with decompensation and SBP. eGFR calculated on serum cystatin C-based equations is more reliable than creatinine-based ones. What is Known: • Acute kidney injury (AKI) is a common complication in cirrhotic adults. • Newer biomarkers have diagnostic and prognostic role in adult cirrhotics. What is New: • Serum cystatin C is a useful biomarker to identify acute kidney injury in cirrhotic children with decompensation. • Glomerular filtration rate calculation is more accurate by cystatin-based equations than creatinine-based equations.

Albumin in Advanced Liver Diseases: The Good and Bad of a Drug!

Human serum albumin is the most abundant plasma protein, and it regulates diverse body functions. In patients with advanced and decompensated cirrhosis, serum albumin levels are low because of a reduction in the hepatocyte mass due to disease per se and multiple therapeutic interventions. Because of their oncotic and nononcotic properties, administration of human albumin solutions (HAS) have been found to be beneficial in patients undergoing large-volume paracentesis or who have hepatorenal syndrome or spontaneous bacterial peritonitis. Albumin also improves the functionality of the immune cells and mitigates the severity and risk of infections in advanced cirrhosis. Its long-term administration can modify the course of decompensated cirrhosis patients by reducing the onset of new complications, improving the quality of life, and probably providing survival benefits. There is, however, a need to rationalize the dose, duration, and frequency of albumin therapy in different liver diseases and stages of cirrhosis. In patients with acute-on-chronic liver failure, potentially toxic oxidized isoforms of albumin increase substantially, especially human nonmercaptalbumin and 2, and nitrosoalbumin. The role of administration of HAS in such patients is unclear. Determining whether removal of the pathological and dysfunctional albumin forms in these patients by "albumin dialysis" is helpful, requires additional studies. Use of albumin is not without adverse events. These mainly include allergic and transfusion reactions, volume overload, antibody formation and coagulation derangements. Considering their cost, limited availability, need for a health care setting for their administration, and potential adverse effects, judicious use of HAS in liver diseases is advocated. There is a need for new albumin molecules and economic alternatives in hepatologic practice.

Risk Factors and Prognosis of New-Onset Chronic Kidney Disease Following Orthotopic Liver Transplantation: A Retrospective Case-Control Study

Background

We have undertaken this investigation to explore the perioperative risk factors of new-onset chronic kidney disease (NOCKD) after orthotopic liver transplantation (OLT), and to provide an early prediction model for the screening of NOCKD high-risk populations.

Material/Methods

A retrospective case-control study was performed in adult recipients who received OLT in our center between January 2018 and January 2020. Perioperative data were collected using the center’s electronic medical record system. Logistics regression analysis was used to determine risk factors for NOCKD within 1 year following OLT. Kaplan-Meier and log-rank tests were used to evaluate the 1-year survival of recipients with NOCKD or without NOCKD.

Results

A total of 174 patients were included in this study, and 29 patients developed NOCKD after OLT. Logistic multivariate regression analysis showed that preoperative diabetes, high model for end-stage liver disease (MELD) score, postoperative acute kidney injury (AKI), and postoperative renal replacement therapy (RRT) were independent risk factors for NOCKD 1 year after OLT. The 1-year survival rate of NOCKD recipients waas significantly lower than that of patients who did not receive NOCKD.

Conclusions

Diabetes mellitus, MELD score, postoperative AKI, and requirement for postoperative RRT are independent risk factors for NOCKD after OLT, which may have great potential for personalized decision making and predicting the 1-year postoperative mortality of the recipient.

Current knowledge about biomarkers of acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) is common in advanced cirrhosis. Prerenal azotemia, hepatorenal syndrome, and acute tubular necrosis are the main causes of AKI in patients with cirrhosis. Evaluation of renal function and differentiation between functional and structural kidney injury are important issues in the management of cirrhosis. However, AKI in cirrhosis exists as a complex clinical spectrum rather than concrete clinical entity. Based on current evidence, changes in serum creatinine (Cr) levels remain the most appropriate standard for defining AKI in cirrhosis. However, serum Cr has a limited role in assessing renal function in this population. This review examines previous studies that investigated the ability of recent biomarkers for AKI in cirrhosis from the perspective of earlier and accurate diagnosis, classification of AKI phenotype, and prediction of clinical outcomes. Serum cystatin C and urine neutrophil gelatinase-associated lipocalin have been extensively studied in cirrhosis, and have facilitated improved diagnosis and prognosis prediction in patients with AKI. In addition, urine N-acetyl-β-D-glucosaminidase, interleukin 18, and kidney injury molecule 1 are other promising biomarkers for advanced cirrhosis. However, the clinical significance of these markers remains unclear because there are no cut-off values defining the normal range and differentiating phenotypes of AKI. In addition, AKI has been defined in terms of serum Cr, and renal biopsy-the gold standard-has not been carried out in most studies. Further discovery of innovate biomarkers and incorporation of various markers could improve the diagnosis and prognosis prediction of AKI, and will translate into meaningful improvements in patient outcomes.

Progression of Stage 2 and 3 Acute Kidney Injury in Patients With Decompensated Cirrhosis and Ascites

BACKGROUND & AIMS

Progression of stages 2 and 3 acute kidney injury (AKI) in cirrhosis has not been characterized adequately. Patients with higher stages of AKI are believed to have worse outcomes. We assessed outcomes and factors associated with stages 2 and 3 AKI in patients with cirrhosis in the North American Consortium for the Study of End-stage Liver Disease cohort.

METHODS

We collected data from 2297 hospitalized patients with cirrhosis and ascites from December 2011 through February 2017. Our final analysis included 760 patients who developed AKI per the International Ascites Club 2015 definition (419 with maximum stage 1 and 341 with maximum stage 2 or 3; 63% male; mean age, 58 y). We compared demographic features, laboratory values, AKI treatment response, and survival between patients with maximum stage 1 vs patients with stage 2 or 3 AKI.

RESULTS

Patients with stage 2 or 3 AKI had higher Model for End-Stage Liver Disease scores (25.9 ± 7.3) than patients with stage 1 AKI (21.9 ± 7.5) (P < .0001). More patients fulfilled systemic inflammatory response syndrome criteria on admission, and more developed a second nosocomial infection (P < .05 for both comparisons). More patients with stage 2 or 3 AKI also had progression of AKI and required dialysis and admission into intensive care units when compared to stage 1 AKI patients (P < .0001 for both). A lower proportion of patients with stage 2 or 3 AKI survived their hospital stay (80% vs 99% with stage 1 AKI; P < .0001), or survived for 30 days without a liver transplant (56% vs 81%; P < .0001). The development of stage 2 or 3 AKI was associated with a higher Model for End-Stage Liver Disease score at the time of admission (P < .0001), presence of systemic inflammatory response on admission (P = .039), and second infection (P < .0001).

CONCLUSIONS

Based on an analysis of data from the North American Consortium for the Study of End-stage Liver Disease cohort, we found that patients with cirrhosis and more advanced liver disease, as well as a second infection, are more likely to develop stages 2 or 3 AKI, with a progressive course associated with decreased 30-day transplant-free survival. Prevention of AKI progression in patients with cirrhosis and stage 2 or 3 AKI might improve their outcomes.

Indoleamine-2,3-Dioxygenase Activates Wnt/β-Catenin Inducing Kidney Fibrosis after Acute Kidney Injury

INTRODUCTION

As disorder of tryptophan metabolism is common in CKD, the rate-limiting enzyme of tryptophan, indoleamine-2,3-dioxygenase (IDO), has been reported to be involved in CKD, while the accurate mechanism remains unknown. This study was designed to explore correlations between IDO and kidney fibrosis after ischemia-reperfusion injury (IRI).

METHODS

Wild-type (WT) mice and IDO knockout (IDO-/-) mice were divided into the sham group and acute kidney injury (AKI) group. Mice in the sham group underwent dorsal incision and exposure of renal pedicle without clamping renal artery, while mice in the AKI group received unique renal artery IRI, and the contralateral kidney was removed at day 13 after IRI. Blood and IRI kidneys were collected at day 14. Kidney function was analyzed by measuring serum Cr and BUN. Morphology was analyzed by tissue periodic acid-Schiff (PAS) staining and Masson staining. Further, fibrosis markers and Wnt/β-catenin pathway proteins were determined by Western blot. Prostaglandin E2 (PGE2) was administrated for 2 weeks after the IRI mice model was established to observe whether it ameliorates kidney fibrosis after IRI.

RESULTS

WT AKI mice revealed elevated expression of IDO compared with WT sham mice. Kidney function of IDO-/- AKI mice showed better than that of WT AKI mice. PAS staining exhibited less loss of tubular epithelial cells and atrophy tubules in IDO-/- AKI mice. Furthermore, kidney fibrosis areas and the expressions of fibrosis markers, including α-SMA, fibronectin, and vimentin, were increased in WT AKI mice. In addition, GSK-3β and β-catenin were significantly declined in IDO-/- AKI mice. On top of that, PGE2 administration revealed inhibited IDO expression and that reducing GSK-3β and β-catenin resulting in lower expressions of α-SMA, fibronectin, and vimentin in WT AKI mice.

CONCLUSIONS

IRI could increase IDO expression to activate Wnt/β-catenin pathway resulting kidney fibrosis. PGE2 could ameliorate kidney fibrosis via inhibiting IDO expression.

Position paper on liver and kidney diseases from the Italian Association for the Study of Liver (AISF), in collaboration with the Italian Society of Nephrology (SIN)

Liver and kidney are strictly connected in a reciprocal manner, in both the physiological and pathological condition. The Italian Association for the Study of Liver, in collaboration with the Italian Society of Nephrology, with this position paper aims to provide an up-to-date overview on the principal relationships between these two important organs. A panel of well-recognized international expert hepatologists and nephrologists identified five relevant topics: 1) The diagnosis of kidney damage in patients with chronic liver disease; 2) Acute kidney injury in liver cirrhosis; 3) Association between chronic liver disease and chronic kidney disease; 4) Kidney damage according to different etiology of liver disease; 5) Polycystic kidney and liver disease. The discussion process started with a review of the literature relating to each of the five major topics and clinical questions and related statements were subsequently formulated. The quality of evidence and strength of recommendations were graded according to the GRADE system. The statements presented here highlight the importance of strong collaboration between hepatologists and nephrologists for the management of critically ill patients, such as those with combined liver and kidney impairment.

Response to Terlipressin and Albumin Is Associated With Improved Liver Transplant Outcomes in Patients With Hepatorenal Syndrome

BACKGROUND AND AIMS

Although terlipressin and albumin are effective at treating acute kidney injury-hepatorenal syndrome (AKI-HRS), liver transplantation (LT) is the best treatment. However, it is unclear if an effective treatment with terlipressin and albumin improves post-LT outcomes in these patients. The aim of this study was to evaluate the impact of response to treatment with terlipressin and albumin on posttransplant outcomes in patients with AKI-HRS.

APPROACH AND RESULTS

We analyzed two cohorts of patients with cirrhosis listed for LT between 2012 and 2016: 82 patients who developed AKI-HRS before LT and were treated with terlipressin and albumin and 259 patients without AKI-HRS who received transplants during the study period (control group). After LT, patients were followed up until discharge, every month for the first 3 months, and every 3 months thereafter. Of the patients, 43 (52%) responded to terlipressin and albumin. Responders had a better 30-day transplant-free survival (60% vs. 33%, P = 0.006), longer LT waiting list time (37 vs. 17 days, P = 0.041), and lower Model for End-Stage Liver Disease score at the time of LT (23 vs. 29, P = 0.007). Among patients with AKI-HRS receiving transplant, nonresponders required renal replacement therapy (RRT) more frequently than responders (20% vs. 0%, P = 0.024). Nonresponders had a significantly higher incidence of chronic kidney disease (CKD) at 1 year after LT than responders (65% vs. 31%, P = 0.019). In multivariate analysis, nonresponse to terlipressin and albumin was found to be an independent predictor for CKD at 1 year after LT (subdistribution hazard ratio [SHR] = 2.76, P = 0.001), whereas responders did not have an increased risk (SHR = 1.53, P = 0.210).

CONCLUSIONS

In patients with AKI-HRS, response to terlipressin and albumin reduces the need for RRT after LT and reduces the risk of CKD at 1 year after LT.

Monitoring Renal Function and Therapy of Hepatorenal Syndrome Patients with Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis. Patients with cirrhosis can develop AKI due to different causes. Hepatorenal syndrome (HRS) is a unique cause of AKI occurring in patients with advanced cirrhosis and is associated with high short-term mortality. The differential diagnosis between different causes of AKI may be challenging. In this regard, new urine biomarkers may be helpful. Liver transplantation is the definitive treatment of patients with HRS-AKI. Vasoconstrictors and albumin represent the first-line pharmacologic treatment of HRS-AKI. This review summarizes current knowledge for the diagnosis and management of HRS in cirrhosis.

Chronic renal dysfunction in cirrhosis: A new frontier in hepatology

Chronic kidney disease (CKD) in patients with liver cirrhosis has become a new frontier in hepatology. In recent years, a sharp increase in the diagnosis of CKD has been observed among patients with cirrhosis. The rising prevalence of risk factors, such as diabetes, hypertension and nonalcoholic fatty liver disease, appears to have contributed significantly to the high prevalence of CKD. Moreover, the diagnosis of CKD in cirrhosis is now based on a reduction in the estimated glomerular filtration rate of < 60 mL/min over more than 3 mo. This definition has resulted in a better differentiation of CKD from acute kidney injury (AKI), leading to its greater recognition. It has also been noted that a significant proportion of AKI transforms into CKD in patients with decompensated cirrhosis. CKD in cirrhosis can be structural CKD due to kidney injury or functional CKD secondary to circulatory and neurohormonal imbalances. The available literature on combined cirrhosis-CKD is extremely limited, as most attempts to assess renal dysfunction in cirrhosis have so far concentrated on AKI. Due to problems related to glomerular filtration rate estimation in cirrhosis, the absence of reliable biomarkers of CKD and technical difficulties in performing renal biopsy in advanced cirrhosis, CKD in cirrhosis can present many challenges for clinicians. With combined hepatorenal dysfunctions, fluid mobilization becomes problematic, and there may be difficulties with drug tolerance, hemodialysis and decision-making regarding the need for liver vs simultaneous liver and kidney transplantation. This paper offers a thorough overview of the increasingly known CKD in patients with cirrhosis, with clinical consequences and difficulties occurring in the diagnosis and treatment of such patients.

Biomarkers for detecting and improving AKI after liver transplantation: From diagnosis to treatment

Orthotopic liver transplantation (OLT) is a well-established treatment for patients with liver failure. The shortage of donor organs and postoperative complications remain major obstacles for improving patient survival. Among these complications, acute kidney injury (AKI) is one of the most frequent types, contributing to graft loss. The timely detection and reversal of AKI can reduce its adverse influences on graft and patient outcomes. Traditional markers for detecting AKI are often limited with regard to their accuracy and specificity, and the discovery of better AKI markers and therapeutic targets assumes great importance. During past decades, studies directed toward early detection and treatment of AKI in OLT have been available. This review summarizes the evidence of these biomarkers for the prediction, diagnosis, treatment and prognosis stratification of AKI associated with OLT.

Degree of Portal and Systemic Hemodynamic Alterations Predict Recurrent AKI and Chronic Kidney Disease in Patients With Cirrhosis

The relevance of hemodynamic derangements on the incidence of recurrent acute kidney injury (AKI) and chronic kidney disease (CKD) in patients with cirrhosis is largely unknown. Consecutive patients with cirrhosis with a complete record of baseline hemodynamics were followed for identifying risk factors for the development of recurrent AKI and CKD by using negative binomial regression and competing risk analysis, respectively. Consecutive patients with cirrhosis (n = 2013, age 50.1 ± 11.8 years, 80% male, Child A:B:C percentage 13.7:52.9:33.4, and mean Child-Turcotte-Pugh score 8.6 ± 1.8) were enrolled, 893 (44.3%) of whom received beta-blockers, with 44.2% responders. Prior AKI was noted in 12.4% at enrollment. At a median follow-up of 379 (interquartile range: 68-869) days, AKI developed at a rate of 0.37 episodes per person-year, and 26% patients developed CKD. A lower mean number of AKI episodes (0.05 ± 0.25 vs. 0.42 ± 0.868; P < 0.001), CKD (subdistribution hazard ratio 0.74 [0.54-1.02]), and mortality (hazard ratio 0.21 [0.06-0.73]) were observed in beta-blocker responders. Albuminuria was an independent risk factor for recurrent AKI, CKD, and mortality (P < 0.05). Lower systemic vascular resistance index predicted hemodynamic response (odds ratio 2.04 [1.29-3.22]), cumulative AKI episodes (ratio of means 0.10 [0.08-0.14]), and development of CKD (subdistribution hazard ratio 0.70 [0.58-0.83]). Higher hepatic venous pressure gradient (≥17 mm Hg) predicted AKI episodes (ratio of means 1.76 [1.32-2.35]) but not CKD. Conclusion: High portal pressure and severe vasodilatation predispose patients with cirrhosis to repeated AKI episodes and development of CKD. Response to beta-blockers and therapies targeting the vasodilatory state could prevent frequent AKI and the risk of CKD development. Albuminuria could serve as an early marker of renal dysfunction in patients with cirrhosis.

Individualized acute kidney injury after care

PURPOSE OF REVIEW

The aim of this study was to summarize the current evidence around the impact of individualizing patient care following an episode of acute kidney injury (AKI) in the ICU.

RECENT FINDINGS

Over the last years, evidence has demonstrated that the follow-up care after episodes of AKI is lacking and standardization of this process is likely needed. Although this is informed largely by large retrospective cohort studies, a few prospective observational trials have been performed. Medication reconciliation and patient/caregiver education are important tenants of follow-up care, regardless of the severity of AKI. There is evidence the initiation and/or reinstitution of renin-angiotensin-aldosterone agents may improve patient's outcomes following AKI, although they may increase the risk for adverse events, especially when reinitiated early. In addition, 3 months after an episode of AKI, serum creatinine and proteinuria evaluation may help identify patients who are likely to develop progressive chronic kidney disease over the ensuing 5 years. Lastly, there are emerging differences between those who do and do not require renal replacement therapy (RRT) for their AKI, which may require more frequent and intense follow-up in those needing RRT.

SUMMARY

Although large scale evidence-based guidelines are lacking, standardization of post-ICU-AKI is needed.

Obeticholic acid ameliorates hepatorenal syndrome in ascitic cirrhotic rats by down-regulating the renal 8-iso-PGF2α-activated COX-TXA2 pathway

BACKGROUNDS/AIMS

The present study explores the potential of chronic treatment with the Foresaid X receptor (FXR) agonist obeticholic acid (OCA), which inhibits oxidative stress-related pathogenesis, in ascitic cirrhotic rats with hepatorenal syndrome (HRS) developed 6 weeks after bile duct ligation (BDL).

METHODS

Systemic, splanchnic, and renal hemodynamics and pathogenic cascades were measured in ascitic BDL and sham rats receiving 2-weeks of either vehicle or OCA treatments (sham-OCA and BDL-OCA groups), and NRK-52E cells, rat kidney tubular epithelial cells.

RESULTS

Chronic OCA treatment significantly normalized portal hypertension, glomerular filtration rate, urine output, renal blood flow; decreased ascites, renal vascular resistance, serum creatinine, and the release of renal tubular damage markers, including urinary neutrophil gelatinase-associated lipocalin (uNGAL) and kidney injury moleculae-1 (uKim-1) in BDL-OCA rats. In the BDL group, inhibition of the renal oxidative stress (8-iso-PGF2α)-activated cyclooxygenase-thromboxane A2 [COX-TXA2] pathway, apoptosis, and tubular injury accompanied by a decrease in hyper-responsiveness to the vasoconstrictor 8-iso-PGF2α in perfused kidneys. In vitro experiments revealed that 8-iso-PGF2α induced oxidative stress, release of reactive oxygen species, and cell apoptosis, which were reversed by concomitant incubation with the FXR agonist.

CONCLUSIONS

Through the inhibition of renal 8-iso-PGF2α production and the down-regulation of the COX-TXA2 pathway, our study suggests that chronic OCA treatment can ameliorate the HRS in ascitic cirrhotic rats. Thus, OCA is an agent with antioxidative stress, antivasoconstrictive, antiapoptotic properties which benefit ascitic, cirrhotic rats with systemic, hepatic, and renal abnormalities.

Prognosis predictability of serum and urine renal markers in patients with decompensated cirrhosis: A multicentre prospective study

BACKGROUND AND AIMS

This prospective observational study aimed to evaluate the best serum and urine markers to assess predictability for the prognosis of patients with decompensated cirrhosis.

METHODS

Serum creatinine and cystatin C (CysC), and urinary N-acetyl-beta-D glucosaminidase (uNAG) and neutrophil gelatinase-associated lipocalin (uNGAL) levels were measured from hospitalized patients with decompensated cirrhosis.

RESULTS

In total, 328 patients (mean age, 57.2 ± 12.0 years; 237 men) with decompensated cirrhosis were included. Alcoholic liver disease was the most frequent underlying liver disease (68.0%). Acute kidney injury (AKI) was concomitantly present in 41 patients (12.5%) at baseline. INR, serum creatinine and CysC levels, and uNAG and uNGAL levels were significantly higher in patients with AKI. During hospitalization, AKI had progressed in 37 patients (11.3%). In 287 patients without AKI, the incidence of AKI at 3, 6, 9 and 12 months was 15.4%, 22.2%, 28.6% and 32.5% respectively. On multivariate analysis, serum CysC and uNAG levels were independent predictors of AKI, and their optimal cut-off values were 1.055 mg/L and 23.1 U/g urinary Cr respectively. When patients were classified into three groups with these cut-off values of serum CysC and uNAG levels (group 1, both low; group 2, one of two high; and group 3, both high), progression of AKI during hospitalization (P = .001), incidence of AKI in patients without AKI at baseline (P = .001) and mortality rate (P < .001) differed significantly according to serum CysC and uNAG levels.

CONCLUSION

Serum CysC and uNAG levels are useful prognostic markers for renal outcomes and mortality in patients with decompensated cirrhosis.

Terlipressin has stood the test of time: Clinical overview in 2020 and future perspectives

Vasoactive drugs form the mainstay of therapy for two of the most important complications of liver disease: hepatorenal syndrome (HRS) and acute variceal bleed (AVB). With cumulative evidence supporting the use in cirrhosis, terlipressin has been recommended for the management of HRS and AVB. However, owing to the safety concerns, terlipressin was not approved by food and drug administration (FDA) until now. In this review, we discuss the pharmacology and the major practice-changing studies on the safety and efficacy of terlipressin in patients with cirrhosis particularly focusing on existing indications like AVB and HRS and reviewing new data on the expanding indications in liver disease. The references for this review were identified from PUBMED with MeSH terms such as "terlipressin," "hepatorenal syndrome," "varices, esophagal and gastric," "ascites" and "cirrhosis." Terlipressin, a synthetic analogue of vasopressin, was introduced in 1975 to overcome the adverse effects of vasopressin. Terlipressin is an effective drug for HRS reversal in patients with liver cirrhosis and acute-on-chronic liver failure. There is documented mortality benefit with terlipressin therapy in HRS and AVB. Adverse effects are common with terlipressin and need to be monitored strictly. There is some evidence to support the use of this drug in refractory ascites, hepatic hydrothorax, paracentesis-induced circulatory dysfunction and perioperatively during liver transplantation. However, terlipressin is not yet recommended for such indications. In conclusion, terlipressin has stood the test of time with expanding indications and clear prerequisites for clinical use. Our review warrants a fresh perspective on the efficacy and safety of terlipressin.

Cystatin C and Sarcopenia Predict Acute on Chronic Liver Failure Development and Mortality in Patients on the Liver Transplant Waiting List

BACKGROUND

Cystatin C (CysC) is an early biomarker of renal dysfunction scarcely studied in patients awaiting liver transplantation (LT). Sarcopenia is frequent in cirrhosis and impacts prognosis. We aimed to assess the capability of these factors to predict survival and acute-on-chronic liver failure (ACLF) in patients awaiting LT, as well as early post-LT outcomes.

METHODS

Single-center study that included all cirrhotic patients listed for LT between 2014 and 2017. Competing risk regression analysis was used to evaluate the capability of liver-, kidney-, and global status-related variables at waitlist (WL) inclusion to predict WL mortality and ACLF. Variables associated with post-LT outcomes were evaluated with logistic regression analysis.

RESULTS

One-hundred-and-eighty patients were included. Fifty-six (31%) patients developed ACLF, 54 (30%) underwent LT and 35 (19%) died. In the adjusted competing risk regression analysis, CysC ≥ 1.5 mg/L, sarcopenia and MELD-Na were independent predictors of ACLF in the WL, while CysC ≥ 1.5 mg/L, sarcopenia and albumin were independent predictors of mortality. The cumulative incidence of ACLF and mortality at 12 months were 50% and 34% in patients with sarcopenia and CysC ≥1.5 mg/L. An estimated glomerular filtration rate by chronic kidney disease (CKD)-EPI-CysC-creatinine <60 mL/min/1.73 m at WL inclusion was an independent predictor of the need for renal replacement therapy (RRT) in the first month post-LT.

CONCLUSIONS

Higher levels of CysC and sarcopenia are strongly associated with the ACLF and mortality in WL. The assessment of both risk factors may improve the prognostic evaluation and allow identifying a group of patients with a very high risk of poor outcomes while awaiting LT.

Hospital-Acquired Versus Community-Acquired Acute Kidney Injury in Patients With Cirrhosis: A Prospective Study

INTRODUCTION

In patients with cirrhosis, differences between acute kidney injury (AKI) at the time of hospital admission (community-acquired) and AKI occurring during hospitalization (hospital-acquired) have not been explored. We aimed to compare patients with hospital-acquired AKI (H-AKI) and community-acquired AKI (C-AKI) in a large, prospective study.

METHODS

Hospitalized patients with cirrhosis were enrolled (N = 519) and were followed for 90 days after discharge for mortality. The primary outcome was mortality within 90 days; secondary outcomes were the development of de novo chronic kidney disease (CKD)/progression of CKD after 90 days. Cox proportional hazards and logistic regressions were used to determine the independent association of either AKI for primary and secondary outcomes, respectively.

RESULTS

H-AKI occurred in 10%, and C-AKI occurred in 25%. In multivariable Cox models adjusting for significant confounders, only patients with C-AKI had a higher risk for mortality adjusting for model for end-stage liver disease-Na: (hazard ratio 1.64, 95% confidence interval [CI] 1.04-2.57, P = 0.033) and adjusting for acute on chronic liver failure: (hazard ratio 2.44, 95% CI 1.63-3.65, P < 0.001). In univariable analysis, community-acquired-AKI, but not hospital-acquired-AKI, was associated with de novo CKD/progression of CKD (odds ratio 2.13, 95% CI 1.09-4.14, P = 0.027), but in multivariable analysis, C-AKI was not independently associated with de novo CKD/progression of CKD. However, when AKI was dichotomized by stage, C-AKI stage 3 was independently associated with de novo CKD/progression of CKD (odds ratio 4.79, 95% CI 1.11-20.57, P = 0.035).

DISCUSSION

Compared with H-AKI, C-AKI is associated with increased mortality and de novo CKD/progression of CKD in patients with cirrhosis. Patients with C-AKI may benefit from frequent monitoring after discharge to improve outcomes.

Peri-transplant renal dysfunction in patients with non-alcoholic steatohepatitis undergoing liver transplantation

Non-alcoholic fatty liver disease (NAFLD) is currently the most common etiology of chronic liver disease (CLD) caused by an accumulation of fat in the liver and globally is the leading indication of liver transplantation. Emerging data has recognized an increased association of NAFLD with risk of other metabolic liver diseases like type 2 diabetes mellitus, chronic kidney disease (CKD) and cardiovascular diseases. Pathophysiologically, NAFLD patients have a state of low-grade systemic inflammation, insulin resistance and atherogenic dyslipidemia which causes renal dysfunction. Patients with NAFLD cirrhosis awaiting liver transplant (LT) face unique challenges and have a significantly higher requirement of simultaneous-liver-kidney transplant as compared to other etiologies. Further, NAFLD not only recurs but also occurs as a de novo manifestation post-LT. There is also a significantly higher risk of waiting list stagnation and dropouts due to burdensome cardiometabolic disorders in NAFLD patients. The current review aims to understand the prevalence and pathogenetic basis of renal dysfunction in NAFLD. Additionally, the review describes the choice of immunosuppression protocols and use of intraoperative renal replacement therapy in context of intra and post-operative renal dysfunction in NAFLD patients. Prospective controlled trials focusing on NAFLD and development of CKD are needed to assess the existence of a causal and/or a bidirectional relationship between NAFLD and CKD.