TIMP2•IGFBP7 biomarker panel accurately predicts acute kidney injury in high-risk surgical patients. J Trauma Acute Care Surg. 2016;80:243-249. [PMID: 26816218 PMCID: PMC4729326 DOI: 10.1097/ta.0000000000000912]

Does combining urine sediment examination to renal cell arrest and damage biomarkers improve prediction of progression and mortality of sepsis associated acute kidney injury?

BACKGROUND

Sepsis associated acute kidney injury (SA-AKI) among hospitalized patients is common with higher morbidity and mortality. There is a need to discover new methods that allow better prediction of its outcomes and prognosis. We aimed to evaluate if combining serial examination of urine sediment to renal cell damage (KIM-1) and arrest (TIMP-2, IGFBP7) biomarkers could improve the prediction of progression and mortality of SA-AKI.

METHODS

This prospective study enrolled 96 patients with stage 1 or 2 SA-AKI. Measuring of urinary TIMP-2, IGFBP7 and KIM-1 was done at time of AKI diagnosis and examination of urine sediment was performed by calculating Chawla score (CS) and Perazella score (PS) at days 1, 3 and 7. Main study outcomes included AKI progression to stage 3 and mortality.

RESULTS

Ninety-six patients were included in the study. 48% of them progressed to AKI stage 3 and 33.3% died. uTIMP2*IGFBP7 and uKIM-1 showed an area under the curve (AUC) of 0.837 and 0.657 respectively for predicting AKI progression and an AUC of 0.679 and 0.626 respectively for predicting mortality. Combining urine sediment examination at day 3 (P2 and C2) to uTIMP2*IGFBP7, uKIM-1 and both biomarkers significantly improved their prediction ability to an AUC of to 0.977, 0.951 and 0.979 respectively to predict AKI progression, and to an AUC of 0.807, 0.796 and 0.803 respectively to predict mortality.

CONCLUSIONS

Combining urine sediment examination with renal cell damage and arrest biomarkers significantly improved their performance of predicting AKI progression and mortality in patients with SA-AKI.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov Identifier: NCT06064487. First registration date: 21/09/2023.

Urinary [TIMP-2]•[IGFBP7], TIMP-2, IGFBP7, NGAL, and L-FABP for the prediction of acute kidney injury following cardiovascular surgery in Japanese patients

BACKGROUND

Acute kidney injury (AKI) following cardiac surgery is common and is associated with poor outcomes. The combination of urinary tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) is a strong predictor of AKI after cardiac surgery. However, most studies have focused on non-Asian populations, and comparisons with other AKI biomarkers or the optimal timing for measurement have yet to be explored.

METHODS

We prospectively enrolled adult patients at Kochi Medical School Hospital in Kochi, Japan, to assess the predictive values of [TIMP-2]•[IGFBP7], TIMP-2, IGFBP7, neutrophil gelatinase-associated lipocalin (NGAL), and liver fatty acid-binding protein (L-FABP) measured preoperatively and at 2, 4, 6, and 8 h, as well as on day 1 and day 2 after postoperative intensive care unit (ICU) admission, using receiver operating characteristic curve (ROC) analysis.

RESULTS

Of the 38 patients, 13 (34.2%) developed AKI: seven (18.4%) with stage 1, four (10.5%) with stage 2, and two (5.2%) with stage 3. ROC analysis showed that the area under the curve (AUC) for predicting any stage of AKI peaked at 0-4 h, with the highest value at 2 h after ICU admission. Among the biomarkers, [TIMP-2]•[IGFBP7] showed the best AUC at 2 h after ICU admission, followed by TIMP-2, IGFBP7, L-FABP, and NGAL.

CONCLUSIONS

Our study demonstrated the good predictive performance of urine biomarkers, including [TIMP-2]•[IGFBP7], TIMP-2, IGFBP7, NGAL, and L-FABP, for any stage of cardiac surgery-associated AKI (CSA-AKI). The combination of TIMP-2 and IGFBP7 measured 2 h after postoperative ICU admission effectively predicted CSA-AKI, identifying patients at higher risk.

Efficacy of urinary [TIMP-2]⋅[IGFBP7], L-FABP, and NGAL levels for predicting community-acquired acute kidney injury in Japanese patients: a single-center, prospective cohort study

BACKGROUND

The combination of urinary tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) ([TIMP-2]⋅[IGFBP7]) has emerged as a strong predictor of acute kidney injury (AKI), which is associated with poor outcomes. However, most studies have focused on non-Asian populations, and comparisons of [TIMP-2]⋅[IGFBP7] with other AKI biomarkers in Asian populations have not been performed. Furthermore, no study has examined the efficacy of [TIMP-2]⋅[IGFBP7] for predicting community-acquired AKI.

METHODS

We prospectively enrolled adult patients at Kochi Medical School Hospital in Kochi, Japan, and performed a receiver-operating characteristic (ROC) curve analysis to assess the ability of [TIMP-2]⋅[IGFBP7], neutrophil gelatinase-associated lipocalin (NGAL), and liver fatty acid-binding protein (L-FABP) measured at the time of admission to predict AKI.

RESULTS

Of the 170 enrolled patients, 40 (23.5%) developed AKI. Risk factors for AKI development were male sex, history of hypertension, low albumin levels, and high [TIMP-2]⋅[IGFBP7] and NGAL levels. The ROC curve analysis showed that the area under the ROC curve (AUC) of [TIMP-2]•[IGFBP7] for predicting AKI was 0.804 (95% confidence interval [CI], 0.728-0.880); however, the AUCs of L-FABP and NGAL were 0.688 (95% CI, 0.594-0.782) and 0.726 (95% CI, 0.639-0.813), respectively.

CONCLUSION

Urinary [TIMP-2]⋅[IGFBP7] is a good predictor of community-acquired AKI.

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.

Endogenous Tissue Inhibitor of Metalloproteinase-2 Levels Are Associated With High-Quality Neat Semen but Unrelated to Sperm Cryoresistance in Bulls

Tissue Inhibitor of Metalloproteinase-2 (TIMP-2) is part of the tissue inhibitors of the metalloproteinases (TIMPs) family. Its primary function is to regulate the activity of matrix metalloproteinases (MMPs) across various tissues, including those of the reproductive system. This study aimed to quantify the natural levels of TIMP-2 in seminal plasma (SP) and sperm membrane (SM) of bulls, explore potential associations between TIMP-2 levels and semen quality parameters, and examine the relationship between TIMP-2 levels and sperm cryoresistance in bulls. Thirty semen samples from Frieswal breeding bulls were categorized into two groups based on their initial progressive motility (IPM): Good (IPM ≥ 70%; n = 21) and Poor (IPM ≤ 40%; n = 9). The samples were evaluated for their quality parameters at the fresh stage, and TIMP-2 levels were measured in SP and SM using a bovine-specific ELISA kit. Following cryopreservation of Good samples (n = 21), post-thaw motility (PTM) was used to further classify samples into Freezeable (PTM ≥ 50%; n = 14) and Non-Freezable (PTM < 50%; n = 7) groups. In frozen-thawed samples, sperm attributes, kinetics, and functional parameters were assessed, and the results were correlated with retrospective TIMP-2 levels of SP/SM. Our study revealed that the quantified levels of TIMP-2 ranged from 100.27 to 535.95 ng/L in SP and from 0 to 115.78 ng/10 million spermatozoa in SM. TIMP-2 levels in both SP and SM were significantly higher in Good ejaculates compared to Poor ejaculates (p < 0.01). Furthermore, total TIMP-2 levels in the SP/SM of semen samples from bulls showed a positive correlation with fresh semen attributes. However, SP/SM TIMP-2 levels in the Freezeable group did not show any significant differences compared to the Non-Freezable group in post-thaw semen quality attributes, kinetic parameters, and functional tests, except for a significant positive correlation (r = 0.530, p < 0.05) between sperm DNA integrity and SP-TIMP-2 levels. In conclusion, the findings suggested that TIMP-2 can be a positive regulator of semen quality at the neat stage. However, when it comes to the resilience of sperm to cryopreservation, the levels of TIMP-2 do not seem to exert any significant influence in breeding bulls.

Mechanism and clinical role of TIMP-2 and IGFBP-7 in cardiac surgery-associated acute kidney injury: A review

Acute kidney injury (AKI) is a common postoperative complication, but there is still a lack of accurate biomarkers. Cardiac surgery-associated AKI is the most common cause of major-surgery-related AKI, and patients requiring renal replacement therapy have high mortality rates. Early diagnosis, intervention, and management are crucial for improving patient prognosis. However, diagnosing AKI based solely on changes in serum creatinine level and urine output is insufficient, as these changes often lag behind actual kidney damage, making early detection challenging. Biomarkers such as tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein-7 (IGFBP-7) have been found to be significant predictors of moderate-to-severe AKI when combined with urine content analysis. This article reviews the mechanism of biomarkers TIMP-2 and IGFBP-7 in AKI and provides a comprehensive overview of the clinical effects of TIMP-2 and IGFBP-7 in cardiac surgery-associated AKI, including prediction, diagnosis, and progression.

Diagnostic Utility of Urine Microscopy in Kidney Diseases

Urine sediment analysis is a highly valuable yet underutilized test in today's advanced medical landscape. The analysis of urine sediment is a simple, cost-effective, and powerful diagnostic tool in the hands of a skilled nephrologist, generally in all kidney diseases and particularly more so in the setting of acute kidney injury (AKI). The impact of AKI is far-reaching and encompasses elevated mortality rates, increased morbidity, longer hospital stays, and higher overall healthcare expenses. Timely and compartmental diagnosis of AKI with the use of a simple urine sediment analysis leads to targeted therapeutic strategies and also serves as a prognostic guide. The widespread use of automated analysis in recent times has its own set of limitations, as it fails to identify pathological casts, crystals, and dysmorphic red blood cells (RBCs). Hence, it is the need of the hour to learn this time-honored art of urine sediment analysis, to provide comprehensive patient care.

Prognostic Biomarkers and AKI: Potential to Enhance the Identification of Post-Operative Patients at Risk of Loss of Renal Function

Acute kidney injury (AKI) is a common complication after surgery and the more complex the surgery, the greater the risk. During surgery, patients are exposed to a combination of factors all of which are associated with the development of AKI. These include hypotension and hypovolaemia, sepsis, systemic inflammation, the use of nephrotoxic agents, tissue injury, the infusion of blood or blood products, ischaemia, oxidative stress and reperfusion injury. Given the risks of AKI, it would seem logical to conclude that early identification of patients at risk of AKI would translate into benefit. The conventional markers of AKI, namely serum creatinine and urine output are the mainstay of defining chronic kidney disease but are less suited to the acute phase. Such concerns are compounded in surgical patients given they often have significantly reduced mobility, suboptimal levels of nutrition and reduced muscle bulk. Many patients may also have misleadingly low serum creatinine and high urine output due to aggressive fluid resuscitation, particularly in intensive care units. Over the last two decades, considerable information has accrued with regard to the performance of what was termed "novel" biomarkers of AKI, and here, we discuss the most examined molecules and performance in surgical settings. We also discuss the application of biomarkers to guide patients' postoperative care.

Review of the limitations of current biomarkers in acute kidney injury clinical practices

Acute kidney injury is a prevalent disease in hospitalized patients and is continuously increasing worldwide. Various efforts have been made to define and classify acute kidney injury to understand the progression of this disease. Furthermore, deviations from structure and kidney function and the current diagnostic guidelines are not adequately placed due to baseline serum creatinine values, which are rarely known and estimated based on glomerular function rate, resulting in misclassification of acute kidney injury staging. Hence, the current guidelines are still developing to improve and understand the clinical implications of risk factors and earlier predictive biomarkers of acute kidney injury. Yet, studies have indicated disadvantages and limitations with the current acute kidney injury biomarkers, including lack of sensitivity and specificity. Therefore, the present narrative review brings together the most current evidenced-based practice and literature associated with the limitations of the gold standard for acute kidney injury diagnoses, the need for novel acute kidney injury biomarkers, and the process for biomarkers to be qualified for diagnostic use under the following sections and themes. The introduction section situates the anatomy and normal and abnormal kidney functions related to acute kidney injury disorders. Guidelines in providing acute kidney injury definitions and classification are then considered, followed by a discussion of the disadvantages of standard markers used to diagnose acute kidney injury. Characteristics of an ideal acute kidney injury biomarker are discussed concerning sensitivity, specificity, and anatomic location of injury. A particular focus on the role and function of emerging biomarkers is discussed in relation to their applications and significance to the prognosis and severity of acute kidney injury. Findings show emerging markers are early indicators of acute kidney injury prediction in different clinical settings. Finally, the process required for a biomarker to be applied for diagnostic use is explained.

Establishment of Sensitive Sandwich-Type Chemiluminescence Immunoassay for Interleukin-18 in Urinary Samples

Interleukin-18 (IL-18), a member of IL-1 cytokine superfamily, is deemed as an important indicator of the kidney disease. Herein a sandwich chemiluminescence immunoassay integrated with magnetic beads was conducted to detect IL-18 in kidney disease. The detection limit and linear range were 0.0044 ng/mL and 0.01-2.7 ng/mL, respectively. Satisfactory recoveries were ranged from 91.70 to 101.18% with the relative standard deviation below 10%; interference bias of most biomarkers were within allowable deviation range (± 15%). In summary, the whole study was successfully applied to detect IL-18 levels in urine samples for patients with kidney disease. The results showed that chemiluminescence immunoassay for IL-18 detection could be used in the clinical application.

Sepsis-mediated renal dysfunction: Pathophysiology, biomarkers and role of phytoconstituents in its management

Sepsis has evolved as an enormous health issue amongst critically ill patients. It is a major risk factor that results in multiple organ failure and shock. Acute kidney injury (AKI) is one of the most frequent complications underlying sepsis, which portends a heavy burden of mortality and morbidity. Thus, the present review is aimed to provide an insight into the recent progression in the molecular mechanisms targeting dysregulated immune response and cellular dysfunction involved in the development of sepsis-associated AKI, accentuating the phytoconstituents as eligible candidates for attenuating the onset and progression of sepsis-associated AKI. The pathogenesis of sepsis-mediated AKI entails a complicated mechanism and is likely to involve a distinct constellation of hemodynamic, inflammatory, and immune mechanisms. Novel biomarkers like neutrophil gelatinase-associated lipocalin, soluble triggering receptor expressed on myeloid cells 1, procalcitonin, alpha-1-microglobulin, and presepsin can help in a more sensitive diagnosis of sepsis-associated AKI. Many bioactive compounds like curcumin, resveratrol, baicalin, quercetin, and polydatin are reported to play an important role in the prevention and management of sepsis-associated AKI by decreasing serum creatinine, blood urea nitrogen, cystatin C, lipid peroxidation, oxidative stress, IL-1β, TNF-α, NF-κB, and increasing the activity of antioxidant enzymes and level of PPARγ. The plant bioactive compounds could be developed into a drug-developing candidate in managing sepsis-mediated acute kidney injury after detailed follow-up studies. Lastly, the gut-kidney axis may be a more promising therapeutic target against the onset of septic AKI, but a deeper understanding of the molecular pathways is still required.

The Emerging Role of Ferroptosis in Sepsis, Opportunity or Challenge?

Sepsis is a syndrome in multi-organ dysfunction triggered by a deleterious immunological reaction of the body to a condition caused by infection, surgery, or trauma. Currently, sepsis is thought to be primarily associated with abnormal immune responses resulting in organ microcirculatory disturbances, cellular mitochondrial dysfunction, and induced cell death, although the exact pathogenesis of sepsis is still inconclusive. In recent years, the role of abnormal metabolism of trace nutrients in the pathogenesis of sepsis has been investigated. Ferroptosis is a type of cell death that relies on iron and is characterized by unique morphological, biochemical, and genetic features. Unlike other forms of cell death, such as autophagy, apoptosis, necrosis, and pyroptosis, ferroptosis is primarily driven by lipid peroxidation. Ferroptosis cells may be immunogenic, amplify inflammatory responses, cause more cell death, and ultimately induce multi-organ failure. An increasing number of studies have indicated the significance of ferroptosis in sepsis and its role in reducing inflammation. The effectiveness of sepsis treatment has been demonstrated by the use of drugs that specifically target molecules associated with the ferroptosis pathway, including ferroptosis inhibitors. Nevertheless, there is a scarcity of studies investigating the multi-organ dysfunction caused by ferroptosis in sepsis. This article presents a summary and evaluation of recent progress in the role of ferroptosis through molecularly regulated mechanisms and its potential mechanisms of action in the multi-organ dysfunction associated with sepsis. It also discusses the current challenges and prospects in understanding the connection between sepsis and ferroptosis, and proposes innovative ideas and strategies for the treatment of sepsis.

Urinary tissue inhibitor of metalloproteinase-2 as an early predictor for acute kidney injury in critically ill children

Objectives

Acute kidney injury (AKI) is one of the most devastating complications of critical illness in children. Serum creatinine (Scr) is considered the gold standard for AKI diagnosis yet noted to be late and inaccurate. This raises the need for an early and accurate biochemical parameter for the early detection of AKI. This research aimed to explore the role of urinary tissue inhibitor metalloproteinase 2 (TIMP-2) in the early prediction of AKI, compared to standard biomarkers, in critically ill children admitted to pediatric intensive care unit (PICU). Urine TIMP2 was previously explored in multiple adult studies and showed promising results; however, the study of its role in pediatric population was limited.

Methods

This study was a prospective cohort study including 42 critically ill children who are at increased risk of AKI. Cases were recruited from the PICU in the Children's Hospital of Ain-Shams University, Cairo - Egypt over 10 months' duration. Urine samples were collected to measure urinary TIMP-2 and blood samples were taken to measure the levels of Scr, creatinine clearance, and blood urea nitrogen. Urine output in 24 h was also calculated.

Results

Urinary TIMP-2 showed considerably higher levels in AKI compared to non-AKI patients as early as day 1, whereas increased levels of Scr and decreased urine output were noticed later (day 3 and day 5, respectively). A notable correlation existed between TIMP-2 at day 1 and creatinine at day 3.

Conclusion

The present study revealed that urinary TIMP-2 could have an important role in the early prediction of AKI before the increase in Scr and more deterioration in kidney functions.

Real-World Use of AKI Biomarkers: A Quality Improvement Project Using Urinary Tissue Inhibitor Metalloprotease-2 and Insulin-Like Growth Factor Binding Protein 7 ([TIMP-2]*[IGFBP7])

INTRODUCTION

Novel urinary biomarkers, including tissue inhibitor metalloprotease-2 and insulin-like growth factor binding protein 7 ([TIMP-2]*[IGFBP7]), have been developed to identify patients at risk for acute kidney injury (AKI). We investigated the "real-world" clinical utility of [TIMP-2]*[IGFBP7] in preventing AKI.

METHODS

We performed a before and after single-center quality improvement study of intensive care unit (ICU) patients at risk for severe (KDIGO stage 2 or 3) AKI. In the prospective cohort, ICU providers were allowed to order [TIMP-2]*[IGFBP7] for patients at their discretion, then offered AKI practice recommendations based on the results. Outcomes were compared to a historical cohort in which biomarker values were not reported to clinical teams.

RESULTS

There was no difference in 7-day progression to severe AKI between the prospective (n = 116) and historical cohorts (n = 63) when [TIMP-2]*[IGFBP7] ≥0.3 (24 [28%] versus 8 [21%], p = 0.38) despite more stage 1 AKI at time of biomarker measurement in the prospective cohort (58 [67%] versus 9 [23%], p < 0.001). In the prospective cohort, patients with higher [TIMP-2]*[IGFBP7] values were more likely to receive a nephrology consult. Early consultation (within 24 h of biomarker measurement, n = 20) had a nonsignificant trend toward net negative volume balance (-1,787 mL [6,716 mL] versus + 4,974 mL [15,540 mL]) and more diuretic use (19 [95%] versus 8 [80%]) and was associated with less severe AKI (9 [45%] versus 10 [100%], p = 0.004) and inpatient dialysis (2 [10%] versus 7 [70%], p = 0.002) compared to delayed consultation (n = 10).

CONCLUSIONS

Despite the prospective cohort having more preexisting stage 1 AKI, there were equal rates of progression to severe AKI in the prospective and historical cohorts. In the setting of [TIMP-2]*[IGFBP7] reporting, there were more nephrology consults in response to elevated biomarker levels. Early nephrology consultation resulted in improved volume balance and favorable outcomes compared to delayed consultation.

Evaluation of the Efficiency of TIMP-2 as a Biomarker for Acute Kidney Injury in Sepsis

The aim of this study was to evaluate the biomarker potential of TIMP-2 in septic-induced acute kidney injury (AKI). Healthy male rats (n=56, age 8-10 weeks, body weight 250-300 g) were randomized into 3 groups: controls (intact rats, n=6), sham-operated (SO, n=24), and sepsis model (cecum ligation and perforation, CLP, n=24). Thirty minutes before and 6, 12, 24, and 48 h after surgery, blood samples were collected to measure serum creatinine, blood urea nitrogen (BUN), and TIMP-2 and the kidneys were isolated for histopathological analysis and Western blotting. The key sepsis-related genes were screened through bioinformatics analysis. In 24 and 48 h after surgery, 2 rats in the SO group reached the diagnostic criteria of AKI (increased levels of serum creatinine and BUN). In the CLP group, serum creatinine in 6 h after the surgery was slightly higher than 30 min before the surgery, but this change did not meet the diagnostic criteria for AKI. In the CLP group, BUN was normal 6 h after the surgery, but increased after 12 h. In more than 50% rats of the CLP group, serum creatinine and BUN significantly increased 12 h after operation, so this can be diagnosed as AKI. In rats of the CLP group, plasma TIMP-2 was elevated 6 h after surgery and increased with time, suggesting that plasma TIMP-2 can be used as an early marker of AKI. Histological examination of the kidneys in this group revealed destruction of the renal tubular structure, swelling of renal tubular epithelium, the disappearance of brush edge and collapse of necrotic epithelial cells, etc., and the degree of damage increased with time. Immunohistochemistry showed that TIMP-2 was expressed in rats of the CLP group at all terms of the experiment. The expression of TIMP-2 and pyroptosis-related proteins (NLRP3, IL-1β, caspase-1, and GSDMD) in the CLP group was higher than in the SO group (p<0.05) and increased with time, suggesting that pyroptosis is involved in AKI. Thus, plasma TIMP-2 is sensitive indicator for the early detection of kidney injury and can be used as an early biomarker of AKI.

Kinetics of the Cell Cycle Arrest Biomarkers (TIMP2 and IGFBP7) for the Diagnosis of Acute Kidney Injury in Critically Ill COVID-19 Patients

BACKGROUND

Acute kidney injury (AKI) is highly prevalent in critical COVID-19 patients. The diagnosis and staging of AKI are based on serum creatinine (sCr) and urinary output criteria, with limitations in the functional markers. New cell-cycle arrest biomarkers [TIMP2]*[IGFBP7] have been proposed for early detection of AKI, but their role in critically ill COVID-19 patients is poorly understood.

METHODS

We conducted an observational study to assess the performance of [TIMP2]*[IGFBP7] for the detection of AKI in critical COVID-19 patients admitted to our intensive care unit (ICU). We sampled urinary [TIMP2]*[IGFBP7] levels at ICU admission, 12 h, 24 h, and 48 h, and compared the results to the development of AKI, as well as baseline and laboratory data.

RESULTS

Forty-one patients were enrolled. The median age was 66 years [57-72] and most were males (85%). Thirteen patients (31.7%) developed no/mild stage AKI, 19 patients (46.3%) moderate AKI, and nine patients (22.0%) severe AKI. The ICU mortality was 29.3%. sCr levels in the Emergency Department or at ICU admission were not significantly different according to AKI stage. [TIMP-2]*[IGFBP-7] urinary levels were elevated in severe AKI at 12 h after ICU admission, but not at ICU admission or 24 h or 48 h after ICU admission.

CONCLUSION

Urinary biomarkers [TIMP-2]*[IGFBP-7] were generally increased in this population with a high prevalence of AKI, and were higher in patients with severe AKI measured at 12 h from ICU admission. Further studies are needed to evaluate the best timing of these biomarkers in this population.

Single value of NephroCheck™ performed at 4 hours after surgery does not predict acute kidney injury in off-pump coronary artery bypass surgery

Background

Quantification of urinary tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding protein (IFGBP-7), which is commercially known as NephroCheck™(NC) test have been suggested as promising tools for the early detection of acute kidney injury (AKI) after cardiac surgery involving cardio-pulmonary bypass (CPB).

Objectives

The aim of the present study was to test the hypothesis that single value of postoperative NC test performed at 4 hours after surgery can predict AKI in off-pump coronary artery bypass grafting (OPCABG) surgery.

Setting and Design

This prospective single-center study was conducted at the tertiary cardiac center in India from December 2017 to November 2018.

Methods

Ninety adult patients of both sex undergoing elective OPCABG were included. Anesthesia was standardized to all patients. Urine samples were collected preoperatively and at 4 hours after surgery for NC test. Urine output, serum creatinine, estimated glomerular filtration rate (eGFR) were also measured. AKI staging was based on kidney disease improving global outcomes (KDIGO) guidelines.

Statistical Analysis

To assess the predictability of NC test for the primary endpoint, area under the receiver operating characteristic curve (ROC), was calculated.

Results

Thirteen patients developed AKI in the study cohort (14.4%) out of which 7 patients (7.8%) developed stage 2/3 AKI and the remaining stage 1 AKI. Baseline renal parameters were similar between AKI and non-AKI group. The area under curve (AUC) of NC test at 4 hours after surgery was 0.60 [95% confidence interval (CI): 0.42-0.77]. Postoperative NC test performed at 4 hours after surgery did not predict AKI in this study population (P = 0.24). There were no significant differences in duration of mechanical ventilation, length of intensive care stay and hospital stay between the two groups (P > 0.05).

Conclusion

NephroCheck^™ test performed at 4 hours after surgery did not identify patients at risk for developing AKI following OPCABG surgery.

Proficient Novel Biomarkers Guide Early Detection of Acute Kidney Injury: A Review

The definition of acute kidney injury (AKI), despite improvements in criteria, continues to be based on the level of serum creatinine and urinary output that do not specifically indicate tubular function or injury, or glomerular function or injury that is not significant enough to warrant acute hospitalization of the patient. Finding novel biomarkers of AKI has become a major focus nowadays in nephrology to overcome the further complications of end stage renal disease (ESRD). Many compounds, such as KIM 1, IL 18, NGAL, uromodulin, calprotectin, vanin 1, galactin 3, platelet-derived growth factor (PDGF), urinary Na⁺/H⁺ exchanger isoform 3 (NHE3), retinol binding protein (RBP) and Cystatin C, are released from the renal tubules and thus any alterations in tubular function can be detected by measuring these parameters in urine. Additionally, glomerular injury can be detected by measuring immunoglobulin G, nephrin, podocalyxin, podocin, transferrin, netrin-1, pyruvate kinase M2, etc. in urine. These novel biomarkers will be useful for timing the initial insult and assessing the duration of AKI. According to available research, these biomarkers could be applied to assess the onset of AKI, distinguishing between kidney injury and dysfunction, directing the management of AKI, and enhancing disease diagnosis. Therefore, we intend to present recent developments in our understanding of significant biomarkers implicated in various aspects of renal damage. Numerous biomarkers are implicated in various pathophysiological processes that follow renal injury, and can improve prognosis and risk classification.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

Comparative accuracy of biomarkers for the prediction of hospital-acquired acute kidney injury: a systematic review and meta-analysis

Background

Several biomarkers have been proposed to predict the occurrence of acute kidney injury (AKI); however, their efficacy varies between different trials. The aim of this study was to compare the predictive performance of different candidate biomarkers for AKI.

Methods

In this systematic review, we searched PubMed, Medline, Embase, and the Cochrane Library for papers published up to August 15, 2022. We selected all studies of adults (> 18 years) that reported the predictive performance of damage biomarkers (neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP)), inflammatory biomarker (interleukin-18 (IL-18)), and stress biomarker (tissue inhibitor of metalloproteinases-2 × insulin-like growth factor-binding protein-7 (TIMP-2 × IGFBP-7)) for the occurrence of AKI. We performed pairwise meta-analyses to calculate odds ratios (ORs) and 95% confidence intervals (CIs) individually. Hierarchical summary receiver operating characteristic curves (HSROCs) were used to summarize the pooled test performance, and the Grading of Recommendations, Assessment, Development and Evaluations criteria were used to appraise the quality of evidence.

Results

We identified 242 published relevant studies from 1,803 screened abstracts, of which 110 studies with 38,725 patients were included in this meta-analysis. Urinary NGAL/creatinine (diagnostic odds ratio [DOR] 16.2, 95% CI 10.1–25.9), urinary NGAL (DOR 13.8, 95% CI 10.2–18.8), and serum NGAL (DOR 12.6, 95% CI 9.3–17.3) had the best diagnostic accuracy for the risk of AKI. In subgroup analyses, urinary NGAL, urinary NGAL/creatinine, and serum NGAL had better diagnostic accuracy for AKI than urinary IL-18 in non-critically ill patients. However, all of the biomarkers had similar diagnostic accuracy in critically ill patients. In the setting of medical and non-sepsis patients, urinary NGAL had better predictive performance than urinary IL-18, urinary L-FABP, and urinary TIMP-2 × IGFBP-7: 0.3. In the surgical patients, urinary NGAL/creatinine and urinary KIM-1 had the best diagnostic accuracy. The HSROC values of urinary NGAL/creatinine, urinary NGAL, and serum NGAL were 91.4%, 85.2%, and 84.7%, respectively.

Conclusions

Biomarkers containing NGAL had the best predictive accuracy for the occurrence of AKI, regardless of whether or not the values were adjusted by urinary creatinine, and especially in medically treated patients. However, the predictive performance of urinary NGAL was limited in surgical patients, and urinary NGAL/creatinine seemed to be the most accurate biomarkers in these patients. All of the biomarkers had similar predictive performance in critically ill patients.

Trial registrationCRD42020207883, October 06, 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04223-6.

Characterising acute kidney injury: The complementary roles of biomarkers of renal stress and renal function

PURPOSE

Although epidemiological studies have enhanced our understanding of acute kidney injury, defining the biologic processes corresponding to the clinical phenotype remains challenging. We have examined biomarkers associated with renal stress plus markers of glomerular function to assess whether this approach may aid prediction of AKI or other relevant endpoints.

MATERIALS & METHODS

Urinary [TIMP-2]·[IGFBP7], serum creatinine, plasma cystatin C and plasma proenkephalin 119-159 ² were analyzed in patients enrolled in the prospective, international, Sapphire study. Heterogenous critically ill patients (n = 723) were examined with a primary endpoint of development of KDIGO stage 2-3 within 12 h and a secondary endpoint of major adverse kidney events at 30 days (MAKE₃₀).

RESULTS

100 patients (14%) reached the primary endpoint. Markers of renal stress outperformed those associated with glomerular function. Combining [TIMP-2]•[IGFBP7] with serum creatinine, but not the other functional markers, significantly (p = 0.02) increased the area under the ROC curve (AUC) from 0.80 (0.76-0.84) to 0.85 (0.81-0.89). In patients who did not develop AKI, all markers of glomerular filtration, but not [TIMP-2]·[IGFBP7], were significantly elevated in patients with a history of CKD (p < 0.05).

CONCLUSIONS

The combination of cell-cycle arrest biomarkers, TIMP-2 and IGFBP7, with serum creatinine but not cystatin C or PENK improved risk stratification for the development of stage 2 or 3 AKI over [TIMP-2]·[IGFBP7] alone.

Application of New Acute Kidney Injury Biomarkers

Kidney-related biomarkers can provide structural and functional information about different parts of the nephron. These biomarkers can be used to evaluate glomerular, tubular, or interstitial injury, inflammation, or repair, and glomerular or tubular function. Furthermore, biomarkers can improve the acute kidney injury diagnosis in various clinical conditions, including acute interstitial nephritis, acute tubular injury, hepatorenal and cardiorenal syndrome, ischemic and nephrotoxic acute kidney injury, and drug-induced acute kidney injury. Biomarkers might be used as an additional precision medicine tool in managing patients with acute kidney injury; they can help with clinical decision-making and impact patient outcomes. In this chapter, we reviewed the utility of biomarkers used in acute kidney injury.

Reference intervals of urinary kidney injury biomarkers for middle-aged men and women determined by quantitative protein mass spectrometry

BACKGROUND AND AIMS

There is an ongoing need to recognize early kidney injury and its progression in structural chronic pathologies. The proteins NGAL, IGFBP7, TIMP2, KIM-1, CXCL9, TGF-β1, SLC22A2, nephrin, cubilin and uromodulin have been proposed as early kidney injury biomarkers. To guide clinical interpretation, their urinary concentrations should be accompanied by reference intervals, which we here establish in a representative Dutch middle-aged population.

MATERIALS AND METHODS

The 24-h urine samples from 1443 Caucasian middle-aged men and women, were analyzed for the biomarkers by quantitative LC-MS/MS. Biomarker excretion per 24-h were calculated, and urine creatinine and osmolality were measured for dilution normalization. This population was characterized by demographic and anthropometric parameters, comorbid conditions, and conventional kidney function measures.

RESULTS

NGAL, IGFBP7, TIMP2, KIM-1 and uromodulin could be quantified in this population, whereas nephrin, SLC22A2 and CXCL9 were below their detection limits. Urine creatinine and osmolality ( r= -were correlated to urine volume (r = -0.71; -0.74) and to IGFBP7 (r = 0.73; 0.71) and TIMP2 (r = 0.71; 0.69). Crude and normalized biomarker concentrations were affected by sex, but not by age, BMI, smoking, kidney function or common comorbid conditions. The reference intervals (men; women) were 18-108; 21-131 pmol IGFBP7/mmol creatinine, 1- 63; 4-224 pmol NGAL/mmol creatinine, 7-48; 7- 59 pmol TIMP2/mmol creatinine, <1-9; <1-12 pmol KIM-1/mmol creatinine and 0.1-1.2; 0.1-1.7 mg uromodulin/mmol creatinine.

CONCLUSION

We present dilution-normalized and sex-stratified urinary reference intervals of kidney injury biomarkers in a middle-aged Caucasian population.

Biomarkers for early detection and predicting outcomes in acute kidney injury

The current diagnosis of acute kidney injury relies on the measurement of serum creatinine levels and urine output. However, both measures are subject to considerable limitations; for example, change in serum creatinine levels ideally requires a knowledge of baseline function that is often not available. Furthermore, creatinine levels are influenced by many factors including diet, drug therapy, muscle mass, gender and ethnicity, which may lead to underestimation of the extent of renal dysfunction. Similarly, urine output lacks both specificity and sensitivity as a marker of acute kidney injury given that oliguria may be an appropriate physiological response to a multitude of stressors and that output may be maintained until significant renal damage has already occurred.

Given the well-documented consequences of acute kidney injury and the considerable burden associated with its development, much attention has focused on early identification of patients at high risk to try and improve outcomes. Many studies have focused on the identification of candidate molecules that may enable the early detection of individuals at risk of developing acute kidney injury, including constitutive proteins associated with kidney damage, as well as molecules upregulated in response to injury, non-renal products that may be filtered, reabsorbed or secreted by the kidney, and markers of renal stress. Such biomarkers may also aid stratification for adverse events, such as the need for kidney replacement therapy or progression to chronic kidney disease and end-stage kidney disease. This article discusses some of these novel biomarkers and assesses the role they may have in the understanding, management, diagnosis and prognostication of acute kidney injury.

Biomarkers in Cardiorenal Syndrome and Potential Insights Into Novel Therapeutics

Heart and kidney failure often co-exist and confer high morbidity and mortality. The complex bi-directional nature of heart and kidney dysfunction is referred to as cardiorenal syndrome, and can be induced by acute or chronic dysfunction of either organ or secondary to systemic diseases. The five clinical subtypes of cardiorenal syndrome are categorized by the perceived primary precipitant of organ injury but lack precision. Traditional biomarkers such as serum creatinine are also limited in their ability to provide an early and accurate diagnosis of cardiorenal syndrome. Novel biomarkers have the potential to assist in the diagnosis of cardiorenal syndrome and guide treatment by evaluating the relative roles of implicated pathophysiological pathways such as hemodynamic dysfunction, neurohormonal activation, endothelial dysfunction, inflammation and oxidative stress, and fibrosis. In this review, we assess the utility of biomarkers that correlate with kidney and cardiac (dys)function, inflammation/oxidative stress, fibrosis, and cell cycle arrest, as well as emerging novel biomarkers (thrombospondin-1/CD47, glycocalyx and interleukin-1β) that may provide prediction and prognostication of cardiorenal syndrome, and guide potential development of targeted therapeutics.

Combining renal cell arrest and damage biomarkers to predict progressive AKI in patient with sepsis

Background

Sepsis is the most common trigger for AKI and up to 40% of mild or moderate septic AKI would progress to more severe AKI, which is associated with significantly increased risk for death and later CKD/ESRD. Early identifying high risk patients for AKI progression is a major challenge in patients with septic AKI.

Methods

This is a prospective, multicenter cohort study which enrolled adult patients with sepsis and initially developed stage 1 or 2 AKI in the intensive care unit from January 2014 to March 2018. AKI was diagnosed and staged according to 2012 KDIGO-AKI guidelines. Renal cell arrest biomarkers (urinary TIMP2*IGFBP7, u[TIMP-2]*[IGFBP7]) and renal damage biomarkers (urinary KIM-1[uKIM-1] and urinary IL-18 [uIL-18]) were measured at time of AKI clinical diagnosis, and the performance of biomarkers for predicting septic AKI progression alone or in combination were evaluated. The primary outcome was AKI progression defined as worsening of AKI stage. The secondary outcome was AKI progression with subsequent death during hospitalization.

Results

Among 433 screened patients, 149 patients with sepsis and stage 1 or 2 AKI were included, in which 63 patients developed progressive AKI and 49 patients subsequently died during hospitalization. u[TIMP-2]*[IGFBP7], uKIM-1 and uIL-18 independently predicted the progression of septic AKI in which u[TIMP-2]*[IGFBP7] showed the greatest AUC (0.745; 95%CI, 0.667-0.823) as compared to uKIM-1 (AUC 0.719; 95%CI 0.638-0.800) and uIL-18 (AUC 0.619; 95%CI 0.525-0.731). Combination of u[TIMP-2]*[IGFBP7] with uKIM-1 improved the performance of predicting septic AKI progression with AUC of 0.752. u[TIMP-2]*[IGFBP7], alone or combined with uKIM-1/uIL-18, improved the risk reclassification over the clinical risk factor model alone both for the primary and secondary outcomes, as evidenced by significant category-free net reclassification index.

Conclusions

Combination of renal cell arrest and damage biomarkers enhanced the prediction of AKI progression in patients with sepsis and improved risk reclassification over the clinical risk factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02611-8.

Elevated Levels of Urinary Biomarkers TIMP-2 and IGFBP-7 Predict Acute Kidney Injury in Neonates after Congenital Heart Surgery

Objectives  This article investigated the utility of urine biomarkers tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP-7) in identifying acute kidney injury (AKI) in neonates after congenital heart surgery (CHS). TIMP-2 and IGFBP-7 are cell cycle arrest proteins detected in urine during periods of kidney stress/injury. Methods  We conducted a single-center, prospective study between September 2017 and May 2019 with neonates undergoing CHS requiring cardiopulmonary bypass (CPB). Urine samples were analyzed using NephroCheck prior to surgery and 6, 12, 24, and 96 hours post-CPB. All patients were evaluated using the Acute Kidney Injury Network (AKIN) criteria. Wilcoxon rank sum tests were used to compare the medians of the [TIMP-2*IGFBP-7] values in the AKIN negative and positive groups at each time point. Receiver operating characteristic curves were used to measure how well the [TIMP-2*IGFBP-7] values predict AKIN status. Results  Thirty-six patients were included. No patients met the AKIN criteria for AKI preoperatively. Postoperatively, 19 patients (53%) met the AKIN criteria for AKI diagnosis: 13 (36%) stage 1, 5 (14%) stage 2, and 1 (3%) stage 3. None required renal replacement therapy. At the 24-hour time points, patients who met the AKIN criteria for AKI had a statistically significantly higher [TIMP-2*IGFBP7] values than the patients without AKI (1.1 vs. 0.27 [ng/mL] ² /1,000) at 24 hours (adj- p  = 0.0019). Conclusion  AKI is a serious complication associated with adverse outcomes in patients undergoing cardiac surgery. [TIMP-2*IGFBP-7] urinary level 24 hours after CPB is a good predictor of AKI in this population.

Quantitative and qualitative analyses of urinary L-FABP for predicting acute kidney injury after emergency laparotomy

PURPOSE

The aim of this study was to explore the clinical utility of urinary L-FABP for earlier prediction of acute kidney injury (AKI) after emergency laparotomy, and to assess the clinical utility of a point-of-care (POC) kit for urinary L-FABP.

METHODS

Forty-eight patients undergoing emergency laparotomy were divided into AKI and non-AKI groups by the kidney diseases: improving global outcome (KDIGO) criteria. Ten patients were included in the AKI group. Urinary L-FABP, albumin, N-acetyl-β-D-glucosaminidase (NAG), TIMP-2, IGFBP7, serum creatinine (SCr), and blood presepsin were measured perioperatively and compared between groups. Perioperative urinary L-FABP was also evaluated qualitatively using a POC kit.

RESULTS

L-FABP and albumin levels were significantly higher in the AKI group at all measurement points. NAG was significantly higher only postoperatively in the AKI group. There were no inter-group differences in [TIMP-2] × [IGFBP7] at any measuring point. The area under the receiver operating characteristic curve of urinary L-FABP was greater than 0.8 perioperatively, which was larger than that of other biomarkers throughout the study period. The correlation coefficient at 2 h after entering the operating room between quantitative and qualitative tests for urinary L-FABP was 0.714, which was the maximum. The sensitivity, specificity, and negative predictive value of the urinary L-FABP POC kit at 2 h after entry were 55.6%, 91.9%, and 89.5%, respectively.

CONCLUSION

Quantitative L-FABP analyses is suitable for predicting postoperative AKI earlier in the perioperative period of emergency laparotomy. Conversely, the higher specificity of qualitative L-FABP analysis suggests that it may be useful for excluding the risk of AKI but its overall clinical validity should be further investigated.

Cardiorenal Syndrome: New Pathways and Novel Biomarkers

Cardiorenal syndrome (CRS) is a multi-organ disease characterized by the complex interaction between heart and kidney during acute or chronic injury. The pathogenesis of CRS involves metabolic, hemodynamic, neurohormonal, and inflammatory mechanisms, and atherosclerotic degeneration. In the process of better understanding the bi-directional pathophysiological aspects of CRS, the need to find precise and easy-to-use markers has also evolved. Based on the new pathophysiological standpoints and an overall vision of the CRS, the literature on renal, cardiac, metabolic, oxidative, and vascular circulating biomarkers was evaluated. Though the effectiveness of different extensively applied biomarkers remains controversial, evidence for several indicators, particularly when combined, has increased in recent years. From new aspects of classic biomarkers to microRNAs, this review aimed at a 360-degree analysis of the pathways that balance the kidney and the heart physiologies. In this delicate system, different markers and their combination can shed light on the diagnosis, risk, and prognosis of CRS.

Tissue inhibitor metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) best predicts the development of acute kidney injury

Background

Acute kidney injury (AKI) is routinely diagnosed by creatinine-based guidelines, which is sub-optimal marker after injury due to renal and non-renal factors. This has necessitated the need for more specific and sensitive biomarkers for early detection of AKI in at risk patients. This prospective cross-sectional study used the biomarkers of cell cycle arrest and Neutrophil Gelatinase Associated Lipocalin (NGAL) to assess AKI among hospitalized patients.

Methods

We conveniently enrolled 151 in-patients at the Trauma and Specialist Hospital, Winneba in Ghana. Socio-demographic and clinical information were collected using structured questionnaires. Blood samples were collected for the estimation of serum creatinine, and AKI diagnosed and staged using the KDIGO guideline. Fresh urine samples were collected and urinary NGAL, TIMP-2 (tissue inhibitor metalloproteinase 2) and IGFBP-7 (insulin-like growth factor binding protein 7) were estimated using ELISA kits.

Results

The cell cycle arrest biomarkers and NGAL were significantly (P < 0.001) higher among participants with AKI than those without AKI. [TIMP-2]∗[IGFBP-7] showed the best diagnostic performance (AUC = 0.94, CI = 0.90–0.98) followed by [IGFBP-7]∗NGAL] (AUC = 0.93, CI = 0.87–0.99), with NGAL having the least (AUC = 0.62, CI = 0.46–0.78). The cut-off for [TIMP-2]∗[IGFBP-7] showed the best predictive ability (95.8% sensitivity, 77.2% specificity, 44.2% PPV and 99% NPV). The cut-off for NGAL, on the other hand, showed the least predictive ability (62.5% sensitivity, 42.5% specificity, 17.0% PPV and 85.7% NPV).

Conclusion

Tissue inhibitor metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) best predicts the development of AKI, and can be used in high risk patients for early diagnosis of AKI.

Ultrasound Hepatic Vein Ratios Are Associated With the Development of Acute Kidney Injury After Cardiac Surgery

OBJECTIVE

The authors investigated the use of hepatic venous and right-heart ultrasound parameters in predicting cardiac surgery-associated acute kidney injury (AKI).

DESIGN

This was a prospective, contextual, descriptive two-center study. Blood tests,clinical and ultrasound data were obtained preoperatively, and postoperative day one, and day four. The hepatic vein, inferior vena cava, and right-heart Doppler ultrasound parameters were obtained and analyzed.

SETTING

The sites of the study were Johannesburg, South Africa, and Aarhus, Denmark.

PARTICIPANTS

Adult patients who satisfied inclusion criteria, between August 2019 and January 2020, were included, with a total of 152 participants.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The median (interquartile range) age of patients was 68 (55-73) years, predominantly male, and the majority were hypertensive. Of 152 patients analyzed, 54 (35%) patients developed AKI. Among these, 37 (69%) were classified as Kidney Disease: Improving Global Outcomes (KDIGO) stage I, 11 (20%) as stage II, while six (11%) were stage III. Age (adjusted odds ratio [AOR] 1.05, 95% confidence interval [CI] 1.00-1.10 p = 0.031), The European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (AOR 1.43, 95% CI 1.14-1.80, p = 0.005], and preoperative serum creatinine (AOR 1.04, 95% CI 1.01-1.08, p = 0.013) were predictive of AKI. Those who developed AKI had experienced longer cardiopulmonary bypass (CPB) times (p < 0.001). Preoperatively, hepatic vein S-wave measurements were significantly higher in patients with AKI (p < 0.05). On postoperative day one (D1), the hepatic vein flow ratios of patients with AKI were significantly decreased, driven by low S waves and high D waves, and accompanied by significantly elevated central venous pressure (CVP) levels. CVP levels on D1 postoperatively were predictive of AKI (AOR 1.31, 95% CI 1.11-1.55, p = 0.001). Measurements of right ventricular (RV) base, tricuspid annular plane excursion (TAPSE), and inferior vena cava were not associated with the development of AKI (p > 0.05).

CONCLUSION

There was an association between the development of AKI and a decrease in hepatic flow ratios on D1, driven by low S-wave and high D-wave velocities. The presence of venous congestion was reflected by significantly elevated CVP values, which were independently associated with AKI on D1. RV base and TAPSE measurements were, however, not associated with AKI. These parameters may reflect perioperative circumstances, including prolonged CPB times and potential fluid management, which can be modified in this period.

Plasma Endogenous Sulfur Dioxide: A Novel Biomarker to Predict Acute Kidney Injury in Critically Ill Patients

Purpose

Sulfur dioxide (SO₂) is a novel gaseous signaling molecule that plays an important role in inflammation, which contributes the pathogenesis of acute kidney injury (AKI). The aim of this study was to explore the predictive value of plasma SO₂ for AKI in high-risk patients.

Patients and Methods

A prospective cohort of 167 patients who underwent major noncardiac surgery was enrolled in the study. Plasma SO₂, urine neutrophil gelatinase-associated lipocalin (NGAL), tissue inhibitor of metalloproteinase-2 (TIMP-2), and insulin-like growth factor-binding protein 7 (IGFBP7) levels were detected immediately after the operation. The primary endpoint was new-onset AKI within 72 h after admission. The ability of biomarkers including SO₂ and a clinical risk model to predict AKI was compared by receiver operator characteristic (ROC) curve analysis and decision curve analysis (DCA), additional contributions were evaluated by integrated discrimination improvement (IDI) and net reclassification improvement (NRI) analyses.

Results

A total of 61 (36.5%) patients developed AKI within 72 h of surgery. Compared to NGAL and [TIMP-2]·[IGFBP7], SO₂ showed better predictive ability for new-onset AKI with an area under the ROC curve of 0.771 (95% confidence interval: 0.700–0.832, p<0.001). The improvement in predictive value by including SO₂ in the clinical risk model was supported by NRI (0.28; P=0.04) and IDI (0.15; P<0.001) analyses. The net benefit of the combination of SO₂ and clinical variables was the max in DCA.

Conclusion

Plasma SO₂ shows a useful value for predicting new-onset AKI, and improved AKI prediction based on clinical variables, which can guide the implementation of preventive measures for high-risk patients.

Usefulness of the Biomarker TIMP-2•IGFBP7 for Acute Kidney Injury Assessment in Critically Ill Patients: A Narrative Review

OBJECTIVES

To review the clinical usefulness of the biomarker TIMP-2•IGFBP7 in adult, general medical-surgical intensive care unit (ICU) settings.

DATA SOURCES

PubMed (1946 to mid-February 2021) and EMBASE (1947 to mid-February 2021) with bibliographies of retrieved articles reviewed for additional articles.

STUDY SELECTION AND DATA EXTRACTION

Studies evaluating use of the urinary TIMP-2•IGFBP7 assay in adult patients in ICU settings.

DATA SYNTHESIS

Studies published after investigations leading to TIMP-2•IGFBP7 assay approval confirm the appropriateness of considerations discussed in product labeling, such as use of the test within 12 hours of assessment, use of a dichotomous 0.3 (ng/mL)²/1000 cutoff, and use only in combination with other assessments of acute kidney injury (AKI). However, as a biomarker routinely used for early identification of patients at risk for AKI in mixed ICU populations, the additional resources required for TIMP-2•IGFBP monitoring are difficult to justify because of limited data demonstrating usefulness in preventing or ameliorating AKI and its attendant complications.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Biomarkers are potentially useful not only for assessment and diagnosis of AKI, but also for practitioners involved in the management of nephrotoxic medications and medications needing adjustment for decreased kidney function.

CONCLUSIONS

Although there is evidence to suggest that the urinary TIMP-2•IGFBP7 biomarker is helpful in predicting AKI progression in general medical-surgical ICU patients when used within 12 hours of patient assessment in combination with routine testing, including serum creatinine and urine output, there is little evidence that its use leads to improvements in clinically important patient outcomes.

Polarization of Macrophages in Insects: Opening Gates for Immuno-Metabolic Research

Insulin resistance and cachexia represent severe metabolic syndromes accompanying a variety of human pathological states, from life-threatening cancer and sepsis to chronic inflammatory states, such as obesity and autoimmune disorders. Although the origin of these metabolic syndromes has not been fully comprehended yet, a growing body of evidence indicates their possible interconnection with the acute and chronic activation of an innate immune response. Current progress in insect immuno-metabolic research reveals that the induction of insulin resistance might represent an adaptive mechanism during the acute phase of bacterial infection. In Drosophila, insulin resistance is induced by signaling factors released by bactericidal macrophages as a reflection of their metabolic polarization toward aerobic glycolysis. Such metabolic adaptation enables them to combat the invading pathogens efficiently but also makes them highly nutritionally demanding. Therefore, systemic metabolism has to be adjusted upon macrophage activation to provide them with nutrients and thus support the immune function. That anticipates the involvement of macrophage-derived systemic factors mediating the inter-organ signaling between macrophages and central energy-storing organs. Although it is crucial to coordinate the macrophage cellular metabolism with systemic metabolic changes during the acute phase of bacterial infection, the action of macrophage-derived factors may become maladaptive if chronic or in case of infection by an intracellular pathogen. We hypothesize that insulin resistance evoked by macrophage-derived signaling factors represents an adaptive mechanism for the mobilization of sources and their preferential delivery toward the activated immune system. We consider here the validity of the presented model for mammals and human medicine. The adoption of aerobic glycolysis by bactericidal macrophages as well as the induction of insulin resistance by macrophage-derived factors are conserved between insects and mammals. Chronic insulin resistance is at the base of many human metabolically conditioned diseases such as non-alcoholic steatohepatitis, atherosclerosis, diabetes, and cachexia. Therefore, revealing the original biological relevance of cytokine-induced insulin resistance may help to develop a suitable strategy for treating these frequent diseases.

(TIMP2) x (IGFBP7) as early renal biomarker for the prediction of acute kidney injury in aortic surgery (TIGER). A single center observational study

Objective

Postoperative acute kidney injury (po-AKI) is frequently observed after major vascular surgery and impacts on mortality rates. Early identification of po-AKI patients using the novel urinary biomarkers insulin-like growth factor-binding-protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) might help in early identification of individuals at risk of AKI and enable timely introduction of preventative or therapeutic interventions with the aim of reducing the incidence of po-AKI. We investigated whether biomarker-based monitoring would allow for early detection of po-AKI in patients undergoing abdominal aortic interventions.

Methods

In an investigator-initiated prospective single-center observational study in a tertiary care academic center, adult patients with emergency/ elective abdominal aortic repair were included. Patients were tested for concentrations of urinary (TIMP-2) x (IGFBP7) at baseline, after surgical interventions (PO), and in the mornings of the first postoperative day (POD1). The primary endpoint was a difference in urinary (TIMP-2) x (IGFBP7) levels at POD1 in patients with/ without po-AKI (all KDIGO stages, po-AKI until seven days after surgery). Secondary endpoints included sensitivity/ specificity analyses of previously proposed cut-off levels and clinical outcome measures (e.g. need for renal replacement therapy).

Results

93 patients (n = 71 open surgery) were included. Po-AKI was observed in 33% (31/93) of patients. Urinary (TIMP-2) x (IGFBP7) levels at POD1 did not differ between patients with/ without AKI (median 0.39, interquartile range [IQR] 0.13–1.05 and median 0.23, IQR 0.14–0.53, p = .11, respectively) and PO (median 0.2, IQR 0.08–0.42, 0.18, IQR 0.09–0.46; p = .79). Higher median (TIMP-2) x (IGFBP7) levels were noted in KDIGO stage 3 pAKI patients at POD1 (3.75, IQR 1.97–6.92; p = .003). Previously proposed cutoff levels (0.3, 2) showed moderate sensitivity/ specificity (0.58/0.58 and 0.16/0.98, respectively).

Conclusion

In a prospective monocentric observational study in patients after abdominal aortic repair, early assessment of urinary (TIMP-2) x (IGFBP7) did not appear to have adequate sensitivity/ specificity to identify patients that later developed postoperative AKI.

Clinicaltrials.gov

NCT03469765, registered March 19, 2018.

Urinary cell cycle arrest proteins urinary tissue inhibitor of metalloprotease 2 and insulin-like growth factor binding protein 7 predict acute kidney injury after severe trauma: A prospective observational study

BACKGROUND

Recognition and clinical diagnosis of acute kidney injury (AKI) after trauma is difficult. The majority of trauma patients do not have a known true baseline creatinine, which makes application of the guidelines set forth by the international guidelines difficult to apply. Use of alternative biomarkers of renal dysfunction in trauma patients may be beneficial. We hypothesized that urinary tissue inhibitor of metalloprotease 2 (TIMP-2) × insulin-like growth factor binding protein 7 (IGFBP-7) would accurately predict AKI development in severely injured trauma patients.

METHODS

A prospective observational study of adult (≥16 years old) trauma intensive care unit (ICU) patients was performed between September 2018 to March 2019. Urine was collected on ICU admission and was measured for TIMP-2 × IGFBP-7. Univariate, multivariable, and receiver operating characteristic curve analyses were performed using the optimal threshold generated by a Youden index.

MAIN RESULTS

Of 88 included patients, 75% were male, with a median injury severity score was 27 (interquartile range [IQR], 17-34), and age of 40 years (IQR, 28-54 years). Early AKI developed in 39 patients (44%), and of those, 7 (8%) required dialysis within 48 hours. Patients without early AKI had a TIMP-2 × IGFBP-7 of 0.17 U (IQR, 0.1-0.3 U), while patients with early AKI had a TIMP-2 × IGFBP-7 of 0.46 U (IQR, 0.17-1.29 U; p < 0.001). On multivariable analyses, TIMP-2 × IGFBP-7 was associated with AKI development (p = 0.02) and need for dialysis (p = 0.03). Using the optimal threshold 0.33 U to predict AKI, the area under the receiver operating characteristic curve was 0.731, with an accuracy of 0.75, sensitivity of 0.72, and specificity of 0.78.

CONCLUSION

Urinary TIMP-2 × IGFBP-7 measured on ICU admission accurately predicted 48-hour AKI and was independently associated with AKI and dialysis requirement after trauma and is a promising screening tool for treatment.

LEVEL OF EVIDENCE

Prognostic, prospective, observational study, level III.

Clinical adoption of Nephrocheck® in the early detection of acute kidney injury

Acute kidney injury is a common complication of acute illnesses and is associated with increased morbidity and mortality. Over the past years several acute kidney injury biomarkers for diagnostication, decision-making processes, and prognosis of acute kidney injury and its outcomes have been developed and validated. Among these biomarkers, tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7), the so-called cell cycle arrest biomarkers, showed a superior profile of accuracy and stability even in patients with substantial comorbidities. Therefore, in 2014, the US Food and Drug Administration approved the use of the product of TIMP-2 and IGFBP7 ([TIMP-2] × [IGFBP7]), known as cell cycle arrest biomarkers, to aid critical care physicians and nephrologists in the early prediction of acute kidney injury in the critical care setting. To date, Nephrocheck® is the only commercially available test for [TIMP-2] × [IGFBP7]. In this narrative review, we describe the growing clinical and investigational momentum of biomarkers, focusing on [TIMP-2] × [IGFBP7], as one of the most promising candidate biomarkers. Additionally, we review the current state of clinical implementation of Nephrocheck®.

Serial Measurement of Cell-cycle Arrest Biomarkers [TIMP-2]•[IGFBP7] and Risk for Progression to Death, Dialysis or Severe Acute Kidney Injury in Patients with Septic Shock

RATIONALE

Urinary tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) can predict AKI in patients with sepsis.

OBJECTIVES

Since most sepsis patients present with AKI, critical questions are whether biomarkers can inform on the response to treatment and whether they might be used to guide therapy.

METHODS

We measured [TIMP-2]•[IGFBP7] before and after a 6-hour resuscitation in 688 patients with septic shock enrolled in the ProCESS trial. Our primary endpoint was stage 3 AKI, renal replacement therapy or death within 7 days.

MEASUREMENTS AND MAIN RESULTS

The endpoint was reached in 113 patients (16.4%). In patients with negative [TIMP-2]•[IGFBP7] at baseline, those who became positive (>0.3 units) after resuscitation had 3-times higher risk compared to those who remained negative (21.8% vs 8.5%, p=0.01; OR 3.0, 95%CI 1.31-6.87). Conversely, compared to patients with a positive biomarker at baseline that were still positive at hour 6, risk was reduced for patients who became negative (23.8% vs 9.8%, p=0.01; OR 2.15, 95%CI 1.17-3.95). A positive [TIMP-2]•[IGFBP7] following resuscitation was associated with worse outcomes in both patients with and without AKI at that time point. Clinical response to resuscitation, as judged by APACHE II score, was weakly predictive of the endpoint (AUC 0.68, 95%CI 0.62-0.73) and improved with addition of [TIMP-2]•[IGFBP7] (0.72, 95%CI 0.66-0.77 p=0.03). Different resuscitation protocols did not alter biomarker trajectories, nor outcomes in biomarker positive or negative patients. However, biomarker trajectories were associated with outcome.

CONCLUSIONS

Changes in urinary [TIMP-2]•[IGFBP7] following initial fluid resuscitation identify sepsis patients with differing risk for progression of AKI. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT00510835.

Urine Neutrophil Gelatinase-associated Lipocalin (NGAL) for Prediction of Persistent AKI and Major Adverse Kidney Events

We aimed to determine whether urinary neutrophil gelatinase-associated lipocalin (uNGAL) can accurately predict persistent AKI, major adverse kidney events at 30 days (MAKE30) and 365 days (MAKE365) in hospitalized AKI patients. This is a retrospective study of adult patients who were admitted at King Chulalongkorn Memorial Hospital. We performed multivariable logistic regression for persistent AKI, MAKE30, and MAKE365. We developed equations for predicting MAKE30 and MAKE365 and divided the dataset into derivation and validation cohorts. uNGAL performance and predictive models were assessed using the area under the receiver operating characteristic curve (AROC). Among 1,322 patients with AKI, 76.9%, 45.1%, and 61.7% had persistent AKI, MAKE30, and MAKE365. The AROC were 0.75 (95% confidence interval[CI] 0.70–0.80), 0.66 (95%CI 0.61–0.71), and 0.64 (95%CI 0.59–0.70) for prediction of persistent AKI, MAKE30, and MAKE365 by uNGAL. The AROC in the validation dataset combining uNGAL with clinical covariates were 0.74 (95%CI 0.69–0.79) and 0.72 (95%CI 0.67–0.77) for MAKE30 and MAKE365. We demonstrated an association between uNGAL and persistent AKI, MAKE30, and MAKE365. Prediction models combining uNGAL can modestly predict MAKE30 and MAKE365. Therefore, uNGAL is a useful tool for improving AKI risk stratification.

The Role of Biomarkers in Acute Kidney Injury

Several biomarkers have been developed to detect acute kidney injury (AKI) and predict outcomes. Most AKI biomarkers have been shown to be expressed before serum creatinine and to be more sensitive and specific than urine output. Only a few studies have examined how implementation can change clinical outcomes. A second generation of AKI biomarkers have been developed. These markers, including tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulinlike growth factor-binding protein 7 (IGFBP7), have obtained regulatory approval in many countries based on large, rigorous clinical studies and small, single-centered trials and have begun to establish clinical utility.

Biomarker Panels in Critical Care

Biomarker panels have the potential to advance the field of critical care medicine by stratifying patients according to prognosis and/or underlying pathophysiology. This article discusses the discovery and validation of biomarker panels, along with their translation to the clinical setting. The current literature on the use of biomarker panels in sepsis, acute respiratory distress syndrome, and acute kidney injury is reviewed.

Use of tissue inhibitor of metalloproteinase 2 and insulin-like growth factor binding protein 7 [TIMP2]•[IGFBP7] as an AKI risk screening tool to manage patients in the real-world setting

PURPOSE

To determine the application of various components of the Kidney Disease Improving Global Outcomes (KDIGO) bundle in managing patients at high-risk for AKI progression ([TIMP2]•[IGFBP7] >0.3) in the real-world setting.

METHODS

Patients with a [TIMP2]•[IGFBP7] test ordered between 5/23/16-2/28/18 were evaluated. We reviewed the medical record for evidence of implementation of the KDIGO bundle in response to biomarker test results. Evidence including explicit documentation in physicians' note discussing [TIMP2]•[IGFBP7] results and implicit evidence from review of dose adjusted medications, discontinued nephrotoxins and therapeutic drug monitoring.

RESULTS

105 [TIMP2]•[IGFBP7] tests were conducted in 100 patients (54% female; mean age 55.4 ± 16.8; 89% in the ICU). Sixty-one patients had a value of >0.3 and 46 (75.4%) of these patients received at least one management strategy consistent with KDIGO. By contrast, nine patients (23.1%) with [TIMP2]•[IGFBP7] ≤0.3 received one or more components of the KDIGO bundle (p < .001).

CONCLUSION

In a real-world setting the use of urinary [TIMP2]•[IGFBP7] as an AKI risk screening tool resulted in differential application of various components of the KDIGO bundle for patient management for those with a positive test result.

Current understanding and future directions in the application of TIMP-2 and IGFBP7 in AKI clinical practice

NephroCheck® is the commercial name of a combined product of two urinary biomarkers, tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7), expressed as [TIMP-2]·[IGFBP7], used to identify patients at high risk of acute kidney injury (AKI). AKI is a common and harmful complication especially in critically-ill patients, which can induce devastating short- and long-term outcomes. Over the past decade, numerous clinical studies have evaluated the utility of several biomarkers (e.g. neutrophil gelatinase-associated lipocalin, interleukin-18, liver-type fatty acid binding protein and kidney injury molecule-1, cystatin C) in the early diagnosis and risk stratification of AKI. Among all these biomarkers, [TIMP-2]·[IGFBP7] was confirmed to be superior in early detection of AKI, before the decrease of renal function is evident. In 2014, the US Food and Drug Administration permitted marketing of NephroCheck® (Astute Medical) (measuring urinary [TIMP-2]·[IGFBP7]) to determine if certain critically-ill patients are at risk of developing moderate to severe AKI. It has since been applied to clinical work in many hospitals of the United States and Europe to improve the diagnostic accuracy and outcomes of AKI patients. Now, more and more research is devoted to the evaluation of its application value, meaning and method in different clinical settings. In this review, we summarize the current research status of [TIMP-2]·[IGFBP7] and point out its future directions.

Urinary Matrix Metalloproteinase-7 and Prediction of AKI Progression Post Cardiac Surgery

Aims

Early detection of patients at high risk for progressive acute kidney injury (AKI) after cardiac surgery remains a major challenge. We aim to evaluate the utility of urinary matrix metalloproteinase-7 (uMMP-7) and other reported biomarkers for predicting AKI progression during postoperative hospital stay.

Methods

We conducted a prospective, multicenter cohort study in 121 adult patients with stage 1 or 2 AKI after cardiac surgery. uMMP-7 and other well-reported biomarkers (uIL-18, uNGAL, and UACR) were measured at time of AKI clinical diagnosis. The primary outcome is the progression of AKI after cardiac surgery, defined as worsening of AKI stage (stage 1 to either stage 2 or stage 3 or from stage 2 to stage 3).

Results

A level of uMMP-7 > 7.8 μg/g Cr at time of AKI diagnosis conveyed an 8-fold risk of AKI progression as compared to those with uMMP-7 < 2.7 μg/g after adjusting for clinical risk factors. The performance of uMMP-7 for predicting progressive AKI was good with an AUC of 0.80. The combination of uMMP-7 and IL-18 produces the greatest AUC for predicting progressive AKI. Addition of uMMP-7 to the clinical risk factor model significantly improved risk reclassification for AKI progression.

Conclusions

uMMP-7, measured at time of AKI clinical diagnosis, is a novel biomarker for predicting the progression of AKI after cardiac surgery. Adding uMMP-7 to the clinical risk factor model may be used as a noninvasive approach to identify a subpopulation that is at high risk for progressive AKI after cardiac surgery.

Urinary TIMP-2 Predicts the Presence and Duration of Delayed Graft Function in Donation After Circulatory Death Kidney Transplant Recipients

BACKGROUND

Urinary tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP7) have been validated as biomarkers for acute kidney injury. We investigated the performance of both markers in predicting the occurrence and duration of functionally defined delayed graft function (fDGF) in donation after circulatory death (DCD) kidney transplant recipients.

METHODS

Urine samples of 74 DCD recipients were analyzed. TIMP-2 and IGFBP7 were measured with ELISA on postoperative days 1 to 7, day 10, week 6, and month 6, and values were corrected for osmolality (mOsm). Immunosuppression consisted of anti-CD25 antibody induction and triple maintenance therapy (steroids, mycophenolate mofetil, and calcineurin inhibitor). Statistical analysis included receiver operating characteristic curves and multivariate logistic regression.

RESULTS

Fifty-one (69%) renal transplant recipients had fDGF, of which 14 experienced prolonged fDGF (≥21 days). TIMP-2/mOsm on day-1 and day-10 adequately identified patients with fDGF (area under the curve [AUC], 0.91) and prolonged fDGF (AUC, 0.80), respectively, whereas IGFBP7/mOsm did not (AUC, 0.63 and 0.60). Multivariate analysis on day 1 identified 24-hour urinary creatinine excretion and TIMP-2/mOsm as significant predictors of fDGF (AUC, 0.90, 95% confidence interval, 0.80-0.98). The best predictors of prolonged fDGF on day 10 were 24-hour urinary creatinine excretion, TIMP-2/mOsm, and total warm ischemia time with an AUC of 0.85 (95% confidence interval, 0.72-0.95). Consecutive TIMP-2/mOsm values showed a decrease in TIMP-2/mOsm before an increase in estimated glomerular filtration rate, enabling us to monitor fDGF and predict resolution of fDGF.

CONCLUSIONS

Urinary TIMP-2, but not IGFBP7, is a promising biomarker to predict the occurrence and duration of fDGF in DCD kidney transplant recipients.

Urinary [TIMP-2] × [IGFBP-7] for predicting acute kidney injury in patients undergoing orthotopic liver transplantation

BACKGROUND

The product of the concentrations of urinary tissue inhibitor of metalloproteinases-2 and insulin-like growth factor binding protein-7 (urinary [TIMP-2] × [IGFBP-7]) has been suggested as biomarker for early detection of acute kidney injury (AKI) in various clinical settings. However, the performance of urinary [TIMP-2] × [IGFBP-7] to predict AKI has never been assessed in patients undergoing orthotopic liver transplantation (OLT). Thus, the aim of this study was to assess the early predictive value of urinary [TIMP-2] × [IGFBP-7] for the development of AKI after OLT.

METHODS

In this observational study, urinary [TIMP-2] × [IGFBP-7] was measured in samples from adult OLT patients. AKI was diagnosed and classified according to KDIGO criteria. Areas under the receiver operating curves (AUC) were calculated to assess predictive values of urinary [TIMP-2] × [IGFBP-7] for the development of AKI.

RESULTS

Forty patients (mean age 55 ± 8 years) were included. Twenty-eight patients (70%) developed AKI stage 1, 2, or 3 within 48 h after OLT. Urinary [TIMP-2] × [IGFBP-7] was not predictive for AKI at the end of OLT (AUC: 0.54, CI [0.32-0.75], P = 0.72), at day 1 (AUC: 0.60, CI [0.41-0.79], P = 0.31), or day 2 after OLT (AUC: 0.63, CI [0.46-0.8], P = 0.18).

CONCLUSION

Based on our results, routine clinical use of urinary [TIMP-2] × [IGFBP-7] cannot be recommended for risk assessment of AKI in patients undergoing OLT.