Urinary biomarkers of acute kidney injury in patients with liver cirrhosis

Recent advances in pathophysiology, diagnosis and management of hepatorenal syndrome: A review

Hepatorenal syndrome with acute kidney injury (HRS-AKI) is a form of rapidly progressive kidney dysfunction in patients with decompensated cirrhosis and/or acute severe liver injury such as acute liver failure. Current data suggest that HRS-AKI occurs secondary to circulatory dysfunction characterized by marked splanchnic vasodilation, leading to reduction of effective arterial blood volume and glomerular filtration rate. Thus, volume expansion and splanchnic vasoconstriction constitute the mainstay of medical therapy. However, a significant proportion of patients do not respond to medical management. These patients often require renal replacement therapy and may be eligible for liver or combined liver-kidney transplantation. Although there have been advances in the management of patients with HRS-AKI including novel biomarkers and medications, better-calibrated studies, more widely available biomarkers, and improved prognostic models are sorely needed to further improve diagnosis and treatment of HRS-AKI.

Urine neutrophil gelatinase-associated lipocalin as a biomarker of acute kidney injury and prognosis in decompensated chronic liver disease: A prospective study

BACKGROUND

Acute kidney injury (AKI) heralds deterioration in patients with decompensated chronic liver disease (DCLD). Serum creatinine (sCr), a component of the model for end-stage liver disease-sodium (MELD-Na) prognostic score, has limitations in patients with DCLD. We evaluated the prognostic role of urine neutrophil gelatinase-associated lipocalin (NGAL) in DCLD and its ability to sub-type AKI.

METHODS

Total 147 consecutive patients hospitalized between June 2018 and June 2020 for complications of DCLD were evaluated. Urine NGAL was estimated and demographic, clinical and biochemical parameters recorded at baseline. Participants were followed up till the end of study period or mortality, whichever came earlier. Primary outcomes included all-cause mortality and time to death after index hospitalization. Secondary outcomes included the presence and type of AKI, need for intensive care unit (ICU) stay, length of ICU/hospital stay, in-hospital mortality, development of new-onset/recurrent AKI and recurrent hospitalization after index admission.

RESULTS

Urine NGAL was highest in acute tubular necrosis (ATN), lowest in pre-renal azotemia (PRA) and intermediate in hepatorenal syndrome (HRS-AKI). Urine NGAL (p = 0.0208) was superior to sCr (p = 0.0388) and inferior to fractionated excretion of sodium (FENa) (p = 0.0013) in stratifying AKI. A cut-off of 203.9 ng/mL discriminated between HRS and PRA with sensitivity 77.8% and specificity 68.7%. Urine NGAL correlated with MELD-Na score, need for ICU stay, in-hospital mortality and mortality at three and six months. Two-year survival was significantly lower in patients with urine NGAL > 205 ng/mL. Addition of log-urine-NGAL score did not improve predictive performance of MELD-Na.

CONCLUSION

Urine NGAL could identify AKI sub-types and correlated with short-term clinical outcomes, including mortality.

Novel biomarkers of acute kidney injury in chronic liver disease: Where do we stand after a decade of research?

Acute kidney injury (AKI) is a frequently encountered complication in decompensated chronic liver disease (CLD) with an estimated prevalence of 20%-50% among hospitalized patients. AKI often heralds the onset of a downhill course in the natural history of CLD. Serum creatinine has several limitations as a stand-alone marker of AKI in patients with decompensated CLD. The concept of hepatorenal syndrome, the prototype of AKI in decompensated CLD, has evolved tremendously over recent years. There is emerging evidence of an additional "structural" component in the pathophysiology of hepatorenal syndrome-AKI, which was previously identified as a purely "functional" form of renal impairment. Lacunae in the existent biochemical arsenal for diagnosis and prognosis of AKI have fueled enthusiastic research in the field of novel biomarkers of kidney injury in patients with cirrhosis. The advent of these biomarkers provides a crucial window of opportunity to improve the diagnosis and clinical outcomes of this vulnerable cohort of patients. This review summarizes the dynamic concept of renal dysfunction in CLD and the available literature on the role of novel biomarkers of AKI in assessing renal function, identifying AKI subtypes, and predicting prognosis. There is special emphasis on the renal tubular injury marker, neutrophil gelatinase-associated lipocalin, the most exhaustively studied biomarker of AKI in the CLD population.

Management and outcomes of hepatorenal syndrome at an urban academic medical center: a retrospective study

OBJECTIVES

This study is aimed to evaluate the management of acute kidney injury (AKI) in our inner city, American hospital. We intended to ascertain whether or not there is prompt recognition of AKI in cirrhosis according to International Club of Ascites and acute kidney injury network criteria as well how effective we are at distinguishing among different causes of AKI. We aimed to calculated the mortality of hepatorenal syndrome (HRS) in our hospital, and to evaluate the adequacy of the established treatment of AKI at each stage of its algorithm.

PATIENTS AND METHODS

ICD diagnostic codes were used to identify patients with liver cirrhosis and acute renal failure. A total of 725 patients met the search criteria. We excluded the patients without clinical or imaging evidence of ascites, heart failure, on hemodialysis, baseline creatinine more than 1.5 mg/dl and patients who died within 48 h of developing acute renal failure. 291 patients met the inclusion criteria. All statistical analyses were performed using SPSS version 23.0 software with a two-sided significance level set at P value less than 0.05.

RESULTS

Mean age was 55.7 ± 0.61 and baseline serum creatinine was 0.94 ± 0.14. 66.5% of patients were African American, 27.3%, Hispanic, and 4.3% White. The average rise in creatinine from baseline was 1.36 ± 0.08 mg/dl. 27.2% of patients met the diagnostic criteria of HRS. 92.3% of patients with HRS received intravenous fluids and 75.4% received intravenous albumin within 48 h of acute creatinine rise. The in-hospital mortality rate was 14.1, 23.3, and 41.5% for patients with pre-renal azotemia, ARF, and HRS, respectively (P < 0.01).

CONCLUSION

This study demonstrates that with present tools, there is significantly higher mortality in HRS despite guideline-based treatment. Biomarkers for early diagnosis of HRS are necessary to avoid delays in initiation of HRS treatment while establishing the diagnosis. As well, worldwide standardization of the treatment of HRS will be important if the outcome is to be improved.

Sex differences in cardiac and renal responses to a high salt diet in Sprague-Dawley rats

High dietary salt intake is an important risk factor for cardiovascular and renal diseases. However, sexual disparity exists in the response of target organs to high salt diet (HSD). To determine how sex affects cardiac and renal functions' response to HSD, 20 weanling Sprague-Dawley rats (10 males and 10 females) were divided into 4 groups of 5 rats each. The rats were fed a normal diet (0.3% NaCl) or HSD (8% NaCl) for 12 weeks. Fluid balance (FB) was determined from 24 hrs water intake and voided urine. Blood pressure (BP) was measured via arterial cannulation under anesthesia (25% w/v urethane and 1% w/v α-chloralose; 5 ml/kg, i.p). Serum levels of troponin I, aminotransaminases, creatinine, urea, uric acid and electrolytes as well as urinary concentration of albumin, creatinine, and electrolytes were measured using appropriate assay kits. Values are presented as mean ± S.E.M, compared by two-way ANOVA and Bonferroni post Hoc test. In the male rat, HSD significantly increased BP, serum: Troponin I, LDH and sodium (p < 0.05), urinary: albumin, sodium, potassium and FB (p < 0.05). In the female rat, HSD increased BP, serum: troponin I, LDH, sodium and creatinine clearance (p < 0.05), urinary: albumin, sodium and potassium (p < 0.01). However, HSD increased more, the BP, serum: Troponin I, LDH, urinary albumin and FB in male rats, while HSD increased urinary sodium more in female rats. Basal values in male vs. female of serum LDH and urinary albumin were significantly different. Thus, sex plays an important role in the response of the heart and kidney to salt stress.

The Role of Urinary Neutrophil Gelatinase-Associated Lipocalin in Predicting Acute Kidney Dysfunction in Patients With Liver Cirrhosis

Background

Early detection of acute kidney dysfunction (AKD) in cirrhotic patients is crucial. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has been identified as an early marker of AKD. The aim of the study was to evaluate serial uNGAL as a marker and predictor of AKD in liver cirrhosis patients.

Methods

Serial uNGAL and serum creatinine (sCr) levels were measured daily during the first 6 days of admission. Furthermore, sCr levels and the estimated glomerular filtration rate (eGFR) were measured after 3 - 6 weeks. The uNGAL levels in patients with and without abnormal sCr were compared.

Results

Fifty-seven consecutive cirrhotic patients were enrolled in the study. Eight of 14 patients (57%) who developed abnormal uNGAL level also had abnormal sCr level (odds ratio (OR) = 3.4, 95% CI: 0.99 - 12.03, P = 0.05). After 6 weeks, 41% of patients exhibited an abnormal uNGAL level and abnormal sCr (OR = 6.7, 95% CI: 1.55 - 28.85, P = 0.01). Area under the curve (AUROC) and the best cut-off point for highest NGAL in 6 days were 0.64 and 72.55 ng/mL, respectively.

Conclusions

There is a modest association between highest uNGAL in the first 6 days of admission and sCr at week 6 in all participants. This may indicate that in cirrhotic patients, uNGAL level during the first 6 days of admission has a potential predictability for the development of high sCr and low eGFR 6 weeks later. The AUROC of 0.64 quantifies the overall ability of uNGAL to discriminate between those individuals who will have a raised sCr levels and those who will not.

Protecting the Kidney in Liver Transplant Candidates: Practice-Based Recommendations From the American Society of Transplantation Liver and Intestine Community of Practice

Acute kidney injury (AKI) and chronic kidney disease (CKD) are common in patients awaiting liver transplantation, and both have a marked impact on the perioperative and long-term morbidity and mortality of liver transplant recipients. Consequently, we reviewed the epidemiology of AKI and CKD in patients with end-stage liver disease, highlighted strategies to prevent and manage AKI, evaluated the changing liver transplant waiting list's impact on kidney function, delineated important considerations in simultaneous liver-kidney transplant selection, and projected possible future transplant policy changes and outcomes. This review was assembled by experts in the field and endorsed by the American Society of Transplantation Liver and Intestinal Community of Practice and Board of Directors and provides practice-based recommendations for preservation of kidney function in patients with end-stage liver disease.

Urine neutrophil gelatinase-associated lipocalin: a diagnostic and prognostic marker for acute kidney injury (AKI) in hospitalized cirrhotic patients with AKI-prone conditions

BACKGROUND

Acute kidney injury (AKI) is known to increase mortality in hospitalized cirrhotic patients; therefore early identification is utmost significance. There are only a few studies evaluating the cut-off level of urine neutrophil gelatinase-associated lipocalin (uNGAL) for diagnosing AKI and its prognostic value in cirrhotic patients. We aimed to determine the accuracy of uNGAL as a biomarker for early identification of AKI and to determine the cut-off level of uNGAL for diagnosing AKI in hospitalized cirrhotic patients; and (2) to explore the association of 30-day liver-related mortality with uNGAL level.

METHODS AND MATERIAL

We prospectively enrolled cirrhotic patients admitted at the King Chulalongkorn Memorial Hospital during May 1, 2011 to Dec 31, 2013. UNGAL levels were measured within 24 h after admission. Clinical and laboratory data were obtained. Patients were followed up to 30 days.

RESULTS

Of 137 cirrhotic hospitalized patients, 121 cirrhotic patients (88.3 %) with AKI-prone conditions were included with mean age of 57.3 ± 14.7 years. Thirty-five patients (29 %) developed AKI within 72 h of admission. The causes of AKI were prerenal azotemia (68.6 %), acute tubular necrosis (25.7 %), hepatorenal syndrome (5.7 %), respectively. The mean uNGAL level was significantly higher in the patients who developed AKI compared with those who did not (290.6 ± 356.3 vs. 54.4 ± 73.7 ng/mL; P = 0.0001). The AUC of uNGAL for diagnosing AKI was 0.83 (95 % [CI]: 0.76-0.91) with the optimal cut-off level of 56 ng/mL, providing 77.1 % sensitivity and 73.3 % specificity. Fourteen percent of subjects died during the 30-day follow-up period. The mean uNGAL levels were significantly higher in the mortality group. The AUC of uNGAL in predicting mortality was 0.75 (95 % [CI]: 0.66-0.85), with a best cut-off level of 72 ng/mL providing 70.6 % sensitivity and 69.2 % specificity. However, in multivariate logistic regression analysis, uNGAL is not an independent factor for 30-day liver-related mortality prediction.

CONCLUSIONS

uNGAL is a valid marker for the early detection of AKI in hospitalized cirrhotic patients with AKI-prone conditions; however, its level could not independently predict 30-day liver-related mortality.