Acute kidney injury in cirrhosis: An immediate threat but also a ticking time bomb

Long journey on the role of long non-coding RNA (lncRNA) in acute kidney injury (AKI)

Acute kidney injury (AKI) has a high rate of morbidity, death, and medical expenses, making it a worldwide public health problem. There are still few viable treatment plans for AKI despite medical advancements. A subclass of non-coding RNAs with over 200 nucleotides in length, long non-coding RNAs (lncRNAs) have a wide range of biological roles. Lately, lncRNAs have become important mediators of AKI and prospective biomarkers. However, current studies show that, via constructing the lncRNA/microRNA/target gene regulatory axis, abnormal expression of lncRNAs has been connected to significant pathogenic processes associated with AKI, such as the inflammatory response, cell proliferation, and apoptosis. In order to compete with mRNAs for binding to the same miRNAs and affect the expression of transcripts targeted by miRNAs, lncRNAs may function as competing endogenous RNAs (ceRNAs). The most widely used approach for researching the biological roles of lncRNAs is the construction of ceRNA regulation networks. Our goal in this article is to deliver an updated review of lncRNAs in AKI and to provide more knowledge on their possible applications as therapeutic targets and AKI biomarkers.

Aurantiamide mitigates acute kidney injury by suppressing renal necroptosis and inflammation via GRPR-dependent mechanism

Acute kidney injury (AKI) manifests as a clinical syndrome characterised by the rapid accumulation of metabolic wastes, such as blood creatinine and urea nitrogen, leading to a sudden decline in renal function. Currently, there is a lack of specific therapeutic drugs for AKI. Previously, we identified gastrin-releasing peptide receptor (GRPR) as a pathogenic factor in AKI. In this study, we investigated the therapeutic potential of a novel Chinese medicine monomer, aurantiamide (AA), which exhibits structural similarities to our previously reported GRPR antagonist, RH-1402. We compared the therapeutic efficacy of AA with RH-1402 both in vitro and in vivo using various AKI models. Our results demonstrated that, in vitro, AA attenuated injury, necroptosis, and inflammatory responses in human renal tubular epithelial cells subjected to repeated hypoxia/reoxygenation and lipopolysaccharide stimulation. In vivo, AA ameliorated renal tubular injury and inflammation in mouse models of ischemia/reperfusion and cecum ligation puncture-induced AKI, surpassing the efficacy of RH-1402. Furthermore, molecular docking and cellular thermal shift assay confirmed GRPR as a direct target of AA, which was further validated in primary cells. Notably, in GRPR-silenced HK-2 cells and GRPR systemic knockout mice, AA failed to mitigate renal inflammation and injury, underscoring the importance of GRPR in AA's mechanism of action. In conclusion, our study has demonstrated that AA serve as a novel antagonist of GRPR and a promising clinical candidate for AKI treatment.

Diagnostic value of combined detection of urine NGAL, KIM-1, and TFF3 in acute tubular necrosis associated with cirrhosis

BACKGROUND

Acute kidney injury (AKI) is a common complication of decompensated cirrhosis with high clinical mortality and poor prognosis, of which acute tubular necrosis (ATN) has the worst prognosis. Timely and accurate identification of ATN is a difficult problem to solve clinically. Previous studies have shown that urinary neutrophil gelatinase-associated lipocalin (NGAL), trefoil factor 3 (TFF3), and kidney injury molecule-1 (KIM-1) have potential value in the differential diagnosis of ATN and other types of AKI in patients with liver cirrhosis, but they still cannot be applied in clinical practice due to the low diagnostic efficacy. It is necessary to further explore whether the combined detection of the indicators can improve their diagnostic efficacy for ATN associated with cirrhosis.

AIM

To analyze the value of urinary NGAL, KIM-1, and TFF3, either alone or in combination, in the differential diagnosis of ATN in patients with cirrhosis complicated with AKI, and explore the cut-off values of urinary NGAL and other indicators in the differential diagnosis of ATN.

METHODS

A total of 190 patients with decompensated cirrhosis were selected, including 108 patients with AKI. They were divided into different subgroups according to the cause of AKI, including 33 cases of prerenal azotemia, 27 cases of acute renal injury with hepatorenal syndrome, and 48 cases of ATN. The value of urinary NGAL, TFF3, and KIM-1, either alone or in combination, in the differential diagnosis of ATN in patients with cirrhosis complicated with AKI was then assessed.

RESULTS

Urinary NGAL was of great value in the differential diagnosis of ATN in patients with cirrhosis complicated with AKI. The area under the curve (AUC) was 0.902; when the diagnostic threshold was 271.8 μg/g Cr, the sensitivity was 81.3% and the specificity was 85.0%. The combination of two biomarkers could improve the efficacy of differential diagnosis, with the diagnostic perfomance of urinary NGAL combined with urinary TFF3 being the best (AUC = 0.933, sensitivity 85.4%, specificity 88.3%).

CONCLUSION

Urinary NGAL, KIM-1, and TFF3 are of great value in differentiating ATN from other types of AKI in patients with cirrhosis. The combined detection of any two of these biomarkers can further improve the diagnostic efficiency, which is worthy of further study and clinical promotion.

Role of urine/serum NGAL ratio in differential diagnosis of acute kidney injury in patients with cirrhosis

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) can be used for the differential diagnosis of acute kidney necrosis (ATN) and other types of acute kidney injury (AKI) in patients with liver cirrhosis complicated with AKI. However, serum NGAL is directly related to urine NGAL, and there are few existing studies on the role of urine /serum NGAL ratio in the differential diagnosis of ATN.

AIM

To assess the significance of serum and urine NGAL as well as urine/serum NGAL ratio in differentiating ATN from other types of AKI in cirrhosis.

METHODS

A total of 180 patients with decompensated cirrhosis were included in the study, of whom 98 were complicated with AKI. According to the etiology of AKI, there were 33 patients with prerenal azotemia, 25 with hepatorenal syndrome-AKI, and 40 with ATN. The patients were divided into different subgroups to assess the value of NGAL in differentiating the types of AKI.

RESULTS

Urine NGAL and urine/serum NGAL ratio showed signi-ficant value in the differential diagnosis of ATN in patients with liver cirrhosis. At an optimal cut-off of 271.35 ng/mL, urine NGAL distinguished ATN from other types of AKI (area under the cuve [AUC] = 0.964; sensitivity, 87.5%; specificity, 96.6%). As well, at an optimal cut-off of 2.96, urine/serum NGAL ratio could also distinguish ATN from other types of AKI (AUC = 0.953, sensitivity 92.5% and specificity 91.4%).

CONCLUSION

Urine NGAL and urine/serum NGAL ratio have significant value in the differential diagnosis of ATN and other types of AKI in patients with liver cirrhosis, which is worthy of further study and clinical promotion.

Current aspects of renal dysfunction after liver transplantation

The development of chronic kidney disease (CKD) after liver transplantation (LT) exerts a severe effect on the survival of patients. The widespread adoption of the model for end-stage liver disease score strongly impacted CKD incidence after the procedure, as several patients are transplanted with previously deteriorated renal function. Due to its multifactorial nature, encompassing pre-transplantation conditions, perioperative events, and nephrotoxic immunosuppressor therapies, the accurate identification of patients under risk of renal disease, and the implementation of preventive approaches, are extremely important. Methods for the evaluation of renal function in this setting range from formulas that estimate the glomerular filtration rate, to non-invasive markers, although no option has yet proved efficient in early detection of kidney injury. Considering the nephrotoxicity of calcineurin inhibitors (CNI) as a factor of utmost importance after LT, early nephroprotective strategies are highly recommended. They are based mainly on delaying the application of CNI during the immediate postoperative-period, reducing their dosage, and associating them with other less nephrotoxic drugs, such as mycophenolate mofetil and everolimus. This review provides a critical assessment of the causes of renal dysfunction after LT, the methods of its evaluation, and the interventions aimed at preserving renal function early and belatedly after LT.