Biomarkers in Acute Kidney Injury

Platinum-based chemotherapies-induced nephrotoxicity: mechanisms, potential treatments, and management

Platinum-based chemotherapies are essential in the treatment of several malignancies. However, such medications can damage the kidneys, frequently leading to both acute and chronic kidney disease. Treatment becomes more difficult for such problems. Physicians may alter chemotherapy regimens and utilize kidney-protecting medications to lessen renal damage. New imaging techniques and biomarkers also aid in the early detection of renal issues. To effectively handle the mentioned situation, oncologists, nephrologists, and pharmacists must collaborate. However, additional study is still required to develop customized therapies, discover strategies to minimize kidney injury and produce new platinum medicines. Hereupon, the present review's authors are being sought to address the causes, prospective treatments, and management of nephrotoxicity caused by platinum-based chemotherapy.

Urinary and Plasma miRNAs in the Early Detection of Acute Kidney Injury and Their Possible Role as Therapeutic Targets

Acute Kidney Injury (AKI) is a severe clinical condition featured by a rapid decrease in kidney function in a short period of time. AKI, which is often secondary to sepsis, ischemia-reperfusion and drug toxicity, is associated to high morbidity and mortality. Moreover, it contributes to the development of chronic kidney disease (CKD), due to maladaptive or incomplete repair mechanisms, resulting in renal fibrosis. Small non-coding RNA has recently emerged as a novel biomarker for the early detection and treatment of AKI. In particular, microRNAs (miRNAs) are non-coding RNA molecules of 21-25 nucleotides regulating the expression of protein-coding genes through sequence-specific recognition. Due to their high stability in biological fluids, such as urine and plasma, they can be reliably analyzed and quantified, and for this reason they can be considered potential diagnostic and therapeutic biomarkers. Specifically, miRNAs have been demonstrated to predict AKI before the increase in creatinine levels, thus improving the management of this syndrome. In this review, we provide a comprehensive overview of the role of urinary and plasma miRNAs in the early detection and treatment of AKI.

Postoperative oliguria after intermediate and high-risk surgeries in critical care, A cohort analysis

INTRODUCTION

Oliguria is commonly used as a cutoff for acute kidney injury (AKI), however, a decrease in urine output is common during surgery and may represent an adaptative response in the perioperative setting rather than a reduction in glomerular filtration rate, leading to a possible overestimation of postoperative AKI incidence. Although this dilemma has been addressed in the intraoperative scenario, the incidence and impact of oliguria in the first postoperative day represents a gap in the current literature. Our main goal is to describe the incidence, risk factors and clinical outcomes related to postoperative oliguria.

METHODS

This was a retrospective cohort conducted in four intensive care units (ICUs) across two private Brazilian hospitals, analyzing patients admitted after intermediate and high-risk surgeries between January 1, 2018 and December 31, 2022.

RESULTS

1476 patients were included in the final analysis. Overall, 656 (44,5 %) were males, and the median age was 61,7 years. Oliguria was identified in 508 (34,4 %) patients within the first 24 h after surgery. Vasopressor requirement at admission, non-elective procedures, male sex and baseline serum creatinine were higher among oliguric patients. Among oliguric patients, age and basal serum creatine were higher among those who experienced AKI. Although only 12,4 % of oliguric patients developed AKI according to serum creatinine criterion, this incidence was significantly higher than in non-oliguric group (3,6 %), RR 3.42, IC 95 % 2.3-5.1 (p < 0.01). AKI recovery, RRT, ICU and hospital free days, and mortality were similar between the groups.

CONCLUSIONS

Postoperative oliguria is common after intermediate and high-risk surgical procedures and increases the risk of AKI. However, oliguria was largely unrelated with kidney disfunction measured by serum creatinine (87,6 %), raising doubts on whether diuresis overestimates AKI incidence in the postoperative setting.

Exploring the Link: DNA Methylation and Kidney Injury Markers in Farmers Exposed to Glyphosate-Surfactant Herbicides

Glyphosate-surfactant herbicides (GSH), widely used herbicides, have raised concerns about their potential nephrotoxic effects. Despite extensive studies, the safety of GSH remains debatable. This study aimed to determine if occupational exposure to GSH causes detectable changes in renal injury biomarkers-specifically DNA methylation, KIM-1, TIMP2, and IGFBP7-in farmers regularly exposed to these chemicals. Two urine samples, pre-task (0-h) and post-task (24-h), were collected to analyze these biomarkers. No significant immediate changes were observed post-exposure, possibly due to personal protective equipment use. Moderate positive correlations were found between IGFBP7 and KIM-1, and IGFBP7 and TIMP2, suggesting early kidney injury. About 50% of subjects had a biomarker ratio greater than 1, indicating increased levels of IGFBP7, TIMP2, and KIM-1 after GSH exposure. This indicates that farmers who regularly spray GSH are at high risk of exposure, potentially leading to significant renal injury. Further long-term studies are needed to assess the chronic effects and validate these biomarkers for monitoring renal health in populations exposed to glyphosate.

The Reality of Evaluating Urine Spot Sodium and Urine Spot Sodium Creatinine Ratio in Furosemide Stress Test as a New Biomarker in Diagnosing Progressive AKI in Critically Ill

How to cite this article: Chatterjee R, Gupta L. The Reality of Evaluating Urine Spot Sodium and Urine Spot Sodium Creatinine Ratio in Furosemide Stress Test as a New Biomarker in Diagnosing Progressive AKI in Critically Ill. Indian J Crit Care Med 2024;28(12):1089-1090.

Role of Spot Urine Sodium in Furosemide Stress Test in Volume-overloaded Critically Ill Patients with Acute Kidney Injury

Introduction and aims

Urine output (UO) in response to furosemide stress test (FST) can predict the progression of acute kidney injury (AKI). This study aimed to assess if changes in UO, urine spot sodium (USS), urine spot sodium creatinine ratio (USSCR) and changes in these parameters over 6 hours could differentiate between progressive and non-progressive AKI.

Materials and methods

Fifty critically ill adults with AKI in acute kidney injury network (AKIN) stages I and II with volume overload were included in this prospective study. The FST was performed with 1 mg/kg intravenous bolus. Hourly UO, USS, USSCR, maximum USS difference (USSDMAX), and maximum USSCR difference (USSCRDMAX) were documented. Any progression of AKI was noted till day 3.

Results

A total of 50 patients were recruited and n = 10 had progressive AKI (PAKI) and n = 40 had non-progressive AKI (NPAKI). Urine output at 1 and 2 h were significantly less in PAKI group. USS0, USS2, USS6, and USSDMAX were comparable between the groups. USSCR0 and USSCR6 were comparable between the groups whereas USSCR2 and USSCRDMAX were significantly less in PAKI group. USSDMAX did not correlate with UO1 (correlation coefficient 0.2, p = 0.16). However, USSCRDMAX showed a poor but significant correlation with UO1 (correlation coefficient 0.3, p = 0.03).

Conclusion

To conclude, hourly UO in the first two hours and maximum change in USSCR within 6 hours following the FST may have an important role in early differentiation of progressive AKI in critically ill patients.

How to cite this article

Suhas P, Anand RK, Baidya DK, Dehran M. Role of Spot Urine Sodium in Furosemide Stress Test in Volume-overloaded Critically Ill Patients with Acute Kidney Injury. Indian J Crit Care Med 2024;28(12):1107-1111.

Early Diagnostic and Prognostic Value of the Urinary TIMP-2 and IGFBP-7 in Acute Kidney Injury in Critically Ill Children

Background

Acute kidney injury (AKI) is a hidden complication among children within pediatric intensive care units (PICU).

Aim

To evaluate the early predictive and diagnostic value of Urinary [TIMP-2][IGFBP7] to detect AKI in PICU patients.

Methods

A case-control study was conducted on 112 children (72 admitted to PICU and 40 healthy controls) Urinary [TIMP-2][IGFBP7] was measured within 24 hours of PICU admission.

Results

Acute kidney injury developed in 52 (72.2%) out of 72 critically ill patients. The AKI group had significantly higher serum creatinine, CRP, and pediatric sequential organ failure assessment score (pSOFA) score (p = 0.001, 0.01, and 0.001, respectively) and significantly lower estimated creatinine clearance (eCCl) (p = 0.001). Urinary [TIMP-2][IGFBP7] was significantly higher in the AKI group as compared with the non-AKI group (p = 0.007). The duration of the PICU stay was 1.8-fold higher in the AKI group (p = 0.004). At the time of study enrollment, 7 (13.5%) patients had normal initial eCCl. 26 patients (50.0%) fulfilled the "Risk," 18 patients (34.6%) the "Injury," 1 patient (1.9%) the "Failure" and 0 patient (0%) the "Loss" criteria. Nine (17%) patients progressed to the next higher pediatrics risk, injury, failure, loss, end-stage renal disease (pRIFLE) stage. Urinary [TIMP-2][IGFBP7] was significantly higher in the "Failure" stage followed by "Injury," stage then the "Risk," stage (p = 0.001). Hypovolemia/dehydration had the highest [TIMP-2][IGFBP7] values followed by sepsis. Urinary [TIMP-2][IGFBP7] was significantly increased in mechanically ventilated and patients who received inotropic medications.

Conclusions

[TIMP-2]·[IGFBP7] was higher in AKI patients compared with non-AKI ones especially cases with hypovolemia and sepsis. It may predict severe morbidity and mortality because its higher levels in mechanically ventilated children and those on positive inotropic support.

How to cite this article

Ismail M, Abdelhamid N, Hasanin HM, Hamed HM, Motawie A, Kamel S, et al. Early Diagnostic and Prognostic Value of the Urinary TIMP-2 and IGFBP-7 in Acute Kidney Injury in Critically Ill Children. Indian J Crit Care Med 2024;28(10):970-976.

From Acute to Chronic: Unraveling the Pathophysiological Mechanisms of the Progression from Acute Kidney Injury to Acute Kidney Disease to Chronic Kidney Disease

This article provides a thorough overview of the biomarkers, pathophysiology, and molecular pathways involved in the transition from acute kidney injury (AKI) and acute kidney disease (AKD) to chronic kidney disease (CKD). It categorizes the biomarkers of AKI into stress, damage, and functional markers, highlighting their importance in early detection, prognosis, and clinical applications. This review also highlights the links between renal injury and the pathophysiological mechanisms underlying AKI and AKD, including renal hypoperfusion, sepsis, nephrotoxicity, and immune responses. In addition, various molecules play pivotal roles in inflammation and hypoxia, triggering maladaptive repair, mitochondrial dysfunction, immune system reactions, and the cellular senescence of renal cells. Key signaling pathways, such as Wnt/β-catenin, TGF-β/SMAD, and Hippo/YAP/TAZ, promote fibrosis and impact renal function. The renin-angiotensin-aldosterone system (RAAS) triggers a cascade leading to renal fibrosis, with aldosterone exacerbating the oxidative stress and cellular changes that promote fibrosis. The clinical evidence suggests that RAS inhibitors may protect against CKD progression, especially post-AKI, though more extensive trials are needed to confirm their full impact.

The role of Proenkephalin A 119-159 in the detection of acute kidney injury after open thoracoabdominal aortic repair

Background: Acute kidney injury (AKI) after open thoracoabdominal aortic aneurysm repairs (TAAA) is a common postoperative complication, associated with increased mortality and morbidity. Early detection and management of the kidney tissue damage remains of paramount importance. The aim of this prospectively conducted, observational trial was to evaluate the clinical applicability of Proenkephalin A 119-159 (penKid) for the detection of postoperative AKI. Patients and methods: Thirty-six patients, planned for elective open TAAA repairs from January 2019 to December 2022, were recruited in two German centres (University Hospital Aachen and Charité - University Hospital Berlin). Blood samples were collected pre-surgery (baseline), directly postoperatively and at 12, 24 and 48 hours after surgery. The penKid concentration in plasma was measured using the immunoluminometric sphingotest® assay kit and they were statistically tested for association with AKI and other clinical parameters. Results: Twenty-four patients (62%) developed moderate or severe AKI postoperatively (Stage 2 or 3 of the KDIGO classification) and they had a significantly increased risk for the development of acute respiratory distress syndrome (p=.023) or a fatal outcome (p=.035). Starting from the 12th hour after surgery, we found penKid correlating with AKI stage 2/3 (12 hour penKid mean in pmol/L: 93.9 vs. 43.1; c index .776, p=.0037) and renal replacement therapy (12 hour c index .779, p=.0035). Patients with multi-organ dysfunction syndrome had significantly increased penKid levels at all timepoints. Conclusions: We found penKid to be a promising biomarker for the early detection of postoperative AKI and in-hospital mortality after open TAAA repair, which may enable the early initiation of organ-protective strategies and reduction of further complications associated with AKI.

MicroRNAs as Biomarkers and Therapeutic Targets for Acute Kidney Injury

Acute kidney injury (AKI) is a clinical syndrome where a rapid decrease in kidney function and/or urine output is observed, which may result in the imbalance of water, electrolytes and acid base. It is associated with poor prognosis and prolonged hospitalization. Therefore, an early diagnosis and treatment to avoid the severe AKI stage are important. While several biomarkers, such as urinary L-FABP and NGAL, can be clinically useful, there is still no gold standard for the early detection of AKI and there are limited therapeutic options against AKI. miRNAs are non-coding and single-stranded RNAs that silence their target genes in the post-transcriptional process and are involved in a wide range of biological processes. Recent accumulated evidence has revealed that miRNAs may be potential biomarkers and therapeutic targets for AKI. In this review article, we summarize the current knowledge about miRNAs as promising biomarkers and potential therapeutic targets for AKI, as well as the challenges in their clinical use.

Acute Kidney Injury: Medical Causes and Pathogenesis

Acute kidney injury (AKI) is a common clinical syndrome characterized by a sudden decline in or loss of kidney function. AKI is not only associated with substantial morbidity and mortality but also with increased risk of chronic kidney disease (CKD). AKI is classically defined and staged based on serum creatinine concentration and urine output rates. The etiology of AKI is conceptually classified into three general categories: prerenal, intrarenal, and postrenal. Although this classification may be useful for establishing a differential diagnosis, AKI has mostly multifactorial, and pathophysiologic features that can be divided into different categories. Acute tubular necrosis, caused by either ischemia or nephrotoxicity, is common in the setting of AKI. The timely and accurate identification of AKI and a better understanding of the pathophysiological mechanisms that cause kidney dysfunction are essential. In this review, we consider various medical causes of AKI and summarize the most recent updates in the pathogenesis of AKI.

Advances in the study of subclinical AKI biomarkers

Acute kidney injury (AKI) is a prevalent and serious illness in all clinical departments, with a high morbidity and death rate, particularly in intensive care units, where prevention and treatment are crucial. As a result, active prevention, early detection, and timely intervention for acute kidney injury are critical. The current diagnostic criteria for acute kidney injury are an increase in serum creatinine concentration and/or a decrease in urine output, although creatinine and urine output merely reflect changes in kidney function, and AKI suggests injury or damage, but not necessarily dysfunction. The human kidney plays a crucial functional reserve role, and dysfunction is only visible when more than half of the renal mass is impaired. Tubular damage markers can be used to detect AKI before filtration function is lost, and new biomarkers have shown a new subset of AKI patients known as "subclinical AKI." Furthermore, creatinine and urine volume are only marginally effective for detecting subclinical AKI. As a result, the search for new biomarkers not only identifies deterioration of renal function but also allows for the early detection of structural kidney damage. Several biomarkers have been identified and validated. This study discusses some of the most promising novel biomarkers of AKI, including CysC, NGAL, KIM-1, lL-18, L-FABP, IGFBP7, TIMP-2, Clusterin, and Penkid. We examine their performance in the diagnosis of subclinical AKI, limitations, and future clinical practice directions.

New Biomarkers in Early Diagnosis of Acute Kidney Injury in Children

Acute Kidney Injury (AKI) is a common condition with a high risk of mortality and morbidity, so, early diagnosis and management of AKI is very important in clinical practice. Despite significant progress in the management of AKI, it still carries high morbidity and mortality. BUN and serum creatinine are not very sensitive nor specific for the diagnosis of AKI because they are affected by many renal and non-renal factors that are independent of kidney injury or kidney function and change significantly only after significant kidney injury and with a substantial time delay. Detection of biomarkers of AKI made predominantly by the injured kidney tissue are essential for the early diagnosis of AKI. An ideal biomarker should be one that could be easily measured, with no interference with other biologic variables, and be able to clarify early phases of kidney damage. The most common biomarkers studied are Neutrophil Gelatinase-Associated Lipocalin (NGAL), Interleukin-18 (IL-18), Kidney Injury Molecule-1 (KIM-1), Cystatin-C, L type Fatty Acid-Binding Protein (L-FABP), N-Acetyl-β-D Glucosaminidase (NAG), netrin-1, vanin-1, and Monocyte Chemoattractant Protein-1 (MCP-1) and calprotectin.

Combination of Pentoxifylline and Ginko Biloba Nephroprotective Effect in Animal Models with Vancomycin-Induced Nephrotoxicity

Antioxidants have been commonly used in medicine for thousands of years. Clinically, pentoxifylline and Ginkgo biloba have beneficial renal effects. Our study evaluated the nephroprotective effect of Gingko biloba in combination with Pentoxifiln in an experimental model of vancomycin-induced nephrotoxicity. Male Winstar rats were used in 3 groups: CONTROL, VANCO and VANCO+GBI+PTX and each group included 6 rats. Insufficient studies in the literature on the prevention of acute kidney injury by the combination of Ginkgo biloba and pentoxifylline led to the necessity to perform the study. Acute kidney injury was demonstrated by measuring serum values of classical markers such as urea and creatinine but also by measuring the urinary N-acetyl-β-d-glucosaminidase index, a topical marker in modern medicine. The significant decrease of the biochemical parameters in group III (VANCO+GBI+PTX) compared to group II (VANCO) and values similar to group I (CONTROL), demonstrates, the nephroprotective effect of the use in combination of the two substances.

Determinants of Outcomes of Acute Kidney Injury: Clinical Predictors and Beyond

Acute kidney injury (AKI) is a common clinical syndrome characterized by rapid impairment of kidney function. The incidence of AKI and its severe form AKI requiring dialysis (AKI-D) has been increasing over the years. AKI etiology may be multifactorial and is substantially associated with increased morbidity and mortality. The outcome of AKI-D can vary from partial or complete recovery to transitioning to chronic kidney disease, end stage kidney disease, or even death. Predicting outcomes of patients with AKI is crucial as it may allow clinicians to guide policy regarding adequate management of this problem and offer the best long-term options to their patients in advance. In this manuscript, we will review the current evidence regarding the determinants of AKI outcomes, focusing on AKI-D.