Neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker for acute renal injury after cardiac surgery

The role of IGFBP-1 in the clinical prognosis and pathophysiology of acute kidney injury

The ability to predict progression to severe acute kidney injury (AKI) remains an unmet challenge. Contributing to the inability to predict the course of AKI is a void of understanding of the pathophysiological mechanisms of AKI. The identification of novel prognostic biomarkers could both predict patient outcomes and unravel the molecular mechanisms of AKI. We performed a multicenter retrospective observational study from a cohort of patients following cardiac surgery. We identified novel urinary prognostic biomarkers of severe AKI among subjects with early AKI. Of 2,065 proteins identified in the discovery cohort, insulin-like growth factor binding protein 1 (IGFBP-1) was the most promising. We validated IGFBP-1 as a prognostic biomarker of AKI in 213 patients. In addition, we investigated its role in the pathophysiology of AKI using a murine model of cisplatin-induced AKI (CIAKI). Urinary IGFBP-1 concentration in samples collected from patients with stage 1 AKI following cardiothoracic surgery was significantly higher in patients who progressed to severe AKI compared with patients who did not progress beyond stage 1 AKI (40.28 ng/ml vs. 2.8 ng/ml, P < 0.0001) and predicted the progression to the composite outcome (area under the curve: 0.85, P < 0.0001). IGFBP-1 knockout mice showed less renal injury, cell death, and apoptosis following CIAKI, possibly through increased activation of the insulin growth factor receptor 1. IGFBP-1 is a clinical prognostic biomarker of AKI and a direct mediator of the pathophysiology of AKI. Therapies that target the IGFBP-1 pathways may help alleviate the severity of AKI.NEW & NOTEWORTHY The ability to predict progression to severe AKI remains an unmet challenge. Early prognostic biomarkers of AKI hold promise to improve patient outcomes by early implementation of clinical therapy, as well as unravel the pathophysiological mechanisms of AKI. Here, we present a novel urinary biomarker, IGFBP-1, that predicts the progression to severe AKI following cardiac surgery. In addition, we show that IGFBP-1 mice are protected against CIAKI, suggesting a mechanistic role for IGFBP-1 in AKI.

Procalcitonin levels in septic and nonseptic subjects with AKI and ESKD prior to and during continuous kidney replacement therapy (CKRT)

BACKGROUND

Procalcitonin is a 14.5 kDa protein used clinically as a marker of sepsis and therapeutic response to antibiotic therapy. However, its utility in critically ill patients with either acute kidney injury (AKI) or end-stage kidney disease (ESKD) who require continuous kidney replacement therapy (CKRT) is unknown. The aim of this study was to determine if plasma levels of procalcitonin could reliably distinguish septic from nonseptic status in patients with AKI or ESKD prior to or during CKRT.

METHODS

Procalcitonin concentrations were measured in plasma of 41 critically ill septic or non-septic subjects with AKI or ESKD prior to CKRT (pre-CKRT) and on days 1, 2, and 3 of CKRT in this retrospective cohort study (n = 111 total plasma measurements). Continuous venovenous hemodialysis was the modality of CKRT in these patients. Sepsis status was stringently defined based on culture results. Effluent procalcitonin levels were ascertained on days 1, 2, and 3 of CKRT to assess the clearance of procalcitonin and effects on plasma levels.

RESULTS

92% (66/72) of the plasma procalcitonin measurements among nonseptic patients with either AKI or ESKD were ≥ 0.5 ng/mL (the diagnostic threshold beyond which bacterial infection is very likely). Prior to CKRT initiation, procalcitonin levels were (median (IQR), ng/mL) 5.6 (1.5-18.9) in nonseptic AKI and 58.1 (6.9-195.5) in septic AKI (P = 0.03) and were 3.3 (1.2-8.3) in nonseptic ESKD and 3.7 (1.4-209.8) in septic ESKD (P = 0.79). However, despite being significantly elevated in septic patients with AKI, substantial overlap among procalcitonin levels was present and ROC curve analysis found no cut point that could reliably separate septic from nonseptic patients. Effluent procalcitonin levels were consistently ~ 20% of plasma levels throughout the course of CKRT (i.e., sieving coefficient was 0.2) suggesting that clearance occurs during therapy. However, plasma procalcitonin levels did not significantly decline during CKRT in either AKI or ESKD.

CONCLUSION

Procalcitonin levels are markedly elevated in nonseptic critically ill patients with either AKI or ESKD and do not effectively distinguish sepsis from nonseptic status prior to or during CKRT. We conclude that procalcitonin testing should be avoided in critically ill patients with kidney failure since results are nonspecific in this population.

TGFB1/CXCL5 axis regulation by LCN2 overexpression: a promising strategy to inhibit colorectal cancer metastasis and enhance prognosis

Background

Distant metastasis remains a major reason for the high recurrence and mortality of colorectal cancer (CRC). However, the underlying molecular mechanisms driving metastasis in CRC remain poorly understood. In this study, we investigated the mechanisms underlying the inhibitory effects of lipocalin-2 (LCN2) on CRC metastasis.

Methods

We assessed the expression and clinical significance of LCN2 in human CRC specimens and CRC cell lines using, immunohistochemistry, and western blot analyses. We evaluated the migratory and invasive capabilities of CRC cells influenced by LCN2 using in vitro transwell assays and in vivo lung metastatic models. RNA sequencing and proteome analysis were employed to identify potential downstream targets of LCN2. Rescue experiments were conducted to further elucidate the potential mechanisms of LCN2 and its downstream effectors in CRC.

Results

LCN2 exhibited high expression levels in human CRC tissues and an inverse correlation with N classification, advanced AJCC stages, and shorter overall survival. LCN2 expression independently predicted a more favorable outcome for CRC patients. Upregulation of LCN2 effectively suppressed CRC cell metastasis both in vitro and in vivo. Mechanistically, Transforming growth factor beta 1 (TGFB1) and C-X-C motif chemokine ligand 5 (CXCL5) were identified as downstream effectors of LCN2, with LCN2 inhibiting CRC metastasis through repression of the TGFB1/CXCL5 axis. Furthermore, either TGF-βR1 inhibitor SB431542 or CXCR2 antagonist SB225002 treatment moderately decreased the migratory and invasive capabilities of DLD-1-LV-shLCN2 cells, whereas the combination treatment of the two agents dramatically decreased the migratory and invasive capabilities of DLD-1-LV-shLCN2 cells.

Conclusions

This study underscores LCN2 as an independent protective factor and prognostic biomarker for CRC patients. Combined treatment with the SB431542 and the SB225002 significantly attenuated LCN2-related CRC metastasis. Targeting the LCN2/TGFB1/CXCL5 axis emerges as a promising therapeutic strategy for managing LCN2-related metastatic CRC.

The potential mechanisms of extracellular vesicles in transfusion-related adverse reactions: Recent advances

Blood transfusion is an irreplaceable clinical treatment. Blood components are differentiated and stored according to specific guidelines. Storage temperatures and times vary depending on the blood component, but they all release extracellular vesicles (EVs) during storage. Although blood transfusions can be life-saving, they can also cause many adverse transfusion reactions, among which the effects of EVs are of increasing interest to researchers. EVs are submicron particles that vary in size, composition, and surface biomarkers, are encapsulated by a lipid bilayer, and are not capable of self-replication. EVs released by blood cells are important contributors to pathophysiologic states through proinflammatory, coagulant, and immunosuppressive effects, which in turn promote or inhibit the associated disease phenotype. Therefore, this review explores the potential mechanisms of hematopoietic-derived EVs in transfusion-associated adverse reactions and discusses the potential of the latest proteomics tools to be applied to the analysis of EVs in the field of transfusion medicine with a view to reducing the risk of blood transfusion.

Beyond creatinine: New methods to measure renal function?

Accurate assessment of kidney function is essential for diagnosing and managing chronic kidney disease (CKD) and acute kidney injury (AKI), adjusting drug dosages, and predicting clinical outcomes. Despite its ubiquitous use, serum creatinine has significant limitations, necessitating the exploration of alternative and complementary biomarkers and technologies. This review revisits the benefits and limitations of serum creatinine, explores other kidney function biomarkers such as Cystatin C and ProEnkephalin, and examines traditional gold-standard techniques, including creatinine clearance, radioisotopes, and inulin clearance. Furthermore, it highlights innovations in real-time glomerular filtration rate (GFR) measurement, such as transdermal monitoring using MB-102 and dual fluorescent tracers. We conclude with a discussion on the development, validation, and clinical integration of these advancements, which may redefine renal function assessment in the years to come.

The pathophysiological significance between autosomal dominant polycystic kidney disease and neutrophil gelatinase-associated lipocalin

Autosomal dominant polycystic kidney disease (ADPKD) is the most common form of polycystic kidney disease (PKD) and is a typical adult-onset multisystem disorder. It is a progressive disease characterized by the disruption of renal tubular integrity, involving the modulation of cellular proliferation and apoptosis. Most ADPKD results from a mutation in either the PKD1 or PKD2 gene encoding polycystin-1 and polycystin-2, respectively. With the inconsistent disease course of ADPKD, biomarkers that can predict the treatment efficacy and rapid progression of the disease are needed. Studies have identified neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker for predicting the progression of ADPKD patients. The NGAL protein is expressed at a low level in the kidneys, which helps to regulate iron transport and participates in epithelial differentiation, inflammation, and cell proliferation. NGAL level also increases in serum and urine during renal detrimental conditions such as ischemia and acute and chronic kidney diseases. On the other hand, some studies have also demonstrated that NGAL may act as a tubulogenic factor controlling cell growth and that the upregulation of the Ngal gene hinders tubular cell proliferation, resulting in significantly reduced cyst growth in cellular and murine models of ADPKD. This review attempts to correlate ADPKD and NGAL based on available research findings to evaluate the therapeutic potential of NGAL in ADPKD.

The prognostic value of estimated glomerular filtration rate change in elderly patients undergoing valvular replacement surgery

BACKGROUND

While the estimated glomerular filtration rate (eGFR) is a common metric for assessing kidney function, its prognostic value in elderly patients undergoing valvular replacement surgery remains uncertain.

METHODS

A total of 4531 elderly patients (aged ≥ 60 years) who underwent valvular replacement surgery at Guangdong Provincial People's Hospital in China were retrospectively included in the study, covering the period from January 2010 to April 2019. The patients were divided into four groups based on the difference between early postoperative and preoperative estimated glomerular filtration rates (eGFR): ΔeGFR ≤ 0, 0 < ΔeGFR ≤ 25, 25 < ΔeGFR < 50, and ΔeGFR ≥ 50. The association between postoperative eGFR changes and both in-hospital and one-year mortality was examined using univariate and multivariate analyses. Kaplan-Meier curves were used to illustrate cumulative hazard rates.

RESULT

Overall, 204 patients (4.5 %) died during their hospital stay, and 344 patients (7.59 %) patients died within one year. Our analysis revealed significant differences in clinical outcomes between patients with ΔeGFR ≤ 0 and those with ΔeGFR ≥ 50. Patients with ΔeGFR ≥ 50 had higher rates of postoperative dialysis (P < 0.001), acute heart failure (P = 0.037), and in-hospital mortality (P < 0.001). Cumulative survival curves showed a markedly higher one-year mortality rate among patients with ΔeGFR ≥ 50 compared to the other three groups (p < 0.0001). Multivariable analyses demonstrated a significant association between ΔeGFR ≥ 50 and both in-hospital mortality (OR = 2.939, P < 0.001) and one-year all-cause mortality (HR = 2.567, P < 0.001).

CONCLUSION

Our study identified ΔeGFR ≥ 50 as an independent risk factor for clinical events and in-hospital mortality.

Cardiopulmonary bypass with deep hypothermic circulatory arrest results in organ-specific transcriptomic responses in pediatric swine

The organ-level molecular response to cardiac surgery with cardiopulmonary bypass (CPB) remains inadequately understood and may be heterogeneous. Here, we measured organ-specific gene expression in a piglet model of CPB with deep hypothermic circulatory arrest (DHCA). Infant piglets underwent peripheral CPB with 75 min of DHCA and 6 h of critical care after separation from CPB. Mechanically ventilated animals served as controls. Tissue was obtained from the lung, kidney, liver, heart, and ileum. RNA sequencing was performed using NovaSeq 6000 and evaluated via differentially expressed gene (DEG) and pathway/network analyses. CPB/DHCA induced significant transcriptomic alterations, with greater changes seen in liver (2,166 DEGs), heart (775 DEGs), and kidney (1,759 DEGs) compared to lung (401 DEGs) and ileum (11 DEGs), and little overlap across organs (<20 % differentially expressed in >1 organ). Key upregulated systems included ribosomal proliferation and mitochondrial assembly in the liver, oxidative stress response and proximal tubular repair in the kidney, myofilament structural genes and pro-hypertrophy pathways in the heart, and solute channels and arginine metabolism in the lung. Downregulation of adaptive immunity genes occurred in multiple organs. Transcriptomics could inform the investigation of targeted therapies and adverse event screening after cardiac surgery.

Urine Neutrophil Gelatinase-Associated Lipocalin in Non-Associative Immune Mediated Hemolytic Anemia: A Prospective Controlled Study in 22 Dogs

BACKGROUND

Urine neutrophil gelatinase-associated lipocalin (uNGAL) is a biomarker for the early diagnosis of AKI.

OBJECTIVES

To evaluate uNGAL in dogs with non-associative immune mediated hemolytic anemia (IMHA) and to evaluate whether uNGAL correlates with disease severity markers, negative prognostic indicators and outcome.

ANIMALS

Twenty-two dogs with non-associative IMHA and 14 healthy dogs.

METHODS

Prospective case-control study. uNGAL was measured by a commercially available ELISA-kit and corrected to urine creatinine (uNGAL to creatinine ratio [UNCR]). uNGAL and UNCR of IMHA cases were compared to that of healthy dogs and the correlation with other clinicopathological markers was evaluated. uNGAL and UNCR were also compared between dogs with a CHAOS or ASA score < 3 and ≥ 3.

RESULTS

uNGAL and UNCR were significantly higher in dogs with IMHA when compared to healthy controls (uNGAL median 114.58 and 0.43 ng/mL, respectively, p < 0.001; UNCR median 174.87 and 0.13 ng/mg, respectively, p < 0.001). uNGAL and UNCR were moderately positively correlated with urea (p = 0.005, r = 0.58, 0.20-0.81 95% CI and p = 0.001, r = 0.64, 0.29-0.84 95% CI, respectively) and total bilirubin (p = 0.003, r = 0.60, 0.22-0.82 95% CI and p = 0.002, r = 0.62, 0.25-0.83 95% CI, respectively). These were also significantly higher in dogs with hemoglobinuria compared to those without (uNGAL: median 269 and 30.99 ng/mL, respectively, p < 0.001; UNCR: median 585.3 and 352 37.47 ng/mg, respectively, p < 0.001). There was no statistically significant difference in uNGAL or UNCR when assessing survival to discharge (p = 0.24 and p = 0.16, respectively, 95% CI).

CONCLUSIONS

This study suggests that renal injury might be underappreciated in dogs with IMHA.

Deficiency of neutrophil gelatinase-associated lipocalin elicits a hemophilia-like bleeding and clotting disorder in mice

ABSTRACT

Coagulation is related to inflammation, but the key pathway, especially innate immune system and coagulation regulation, is not well understood and need to be further explored. Here, we demonstrated that neutrophil gelatinase-associated lipocalin (NGAL), an innate immune inflammatory mediator, is upregulated in patients with thrombosis. Furthermore, it contributes to the initiation and amplification of coagulation, hemostasis, and thrombosis. This occurs by enhancing tissue factor expression on the cell surface, potentiating various clotting factors such as thrombin, kallikrein, factor XIa (FXIa), and FVIIa, promoting thrombin-induced platelet aggregation, and inhibiting antithrombin. NGAL knockout led to strikingly prolonged clot reaction time and kinetic time in thromboelastography analysis, along with reduced thrombus generation angle and lower thrombus maximum amplitude, which were in line with remarkably prolonged activated partial thromboplastin time and prothrombin time. In several mouse hemostasis and thrombosis models, NGAL overexpression or IV administration promoted coagulation and hemostasis and aggravated thrombosis, whereas NGAL knockout or treatment with anti-NGAL monoclonal antibody significantly prolonged bleeding time and alleviated thrombus formation. Notably, NGAL knockout prolonged mouse tail bleeding time or artery occlusion time to over 40 or 60 minutes, respectively, resembling uncontrollable bleeding and clotting disorder seen in hemophilic mice. Furthermore, anti-NGAL monoclonal antibody treatment markedly reduced the formation of blood clots in inflammation-induced thrombosis models. Collectively, these findings unveil a previously unidentified role of NGAL in the processes of coagulation, hemostasis, and thrombosis, as well as the cross talk between innate immunity, inflammation, and coagulation. Thus, modulating NGAL levels could potentially help balance thrombotic and hemorrhagic risks.

Neutrophil Gelatinase-Associated Lipocalin: Biological Aspects and Potential Diagnostic Use in Acute Kidney Injury

Acute kidney injury (AKI) is a syndrome characterized by a rise in creatinine or a decrease in urinary flow, according to the Kidney Disease Improving Global Outcomes (KDIGO) definition. It is diagnosed in 15% of inpatients and 50% of patients in the intensive care unit (ICU), and it is related to increased mortality. As part of a global effort aimed at the elimination of preventable deaths from AKI, there is a growing interest in identifying biomarkers that can be point-of-care and that are not influenced by the variability in patient characteristics in a relevant way. Neutrophil gelatinase-associated lipocalin (NGAL), particularly in its 25 kDa form, which is exclusively released by renal tubules, has emerged as a promising biomarker with potential use in the diagnosis of AKI in the critically ill, including its use in guiding the initiation and/or weaning of renal replacement therapy (RRT). The objective of this review is to summarize the current understanding of NGAL in acute settings, emphasizing biological and genomic insights.

Polysome Profiling Proves Impaired IL-10 and Caspase-8 Translation in PBMCs of Hemodialysis Patients

Triggered by uremic intoxication, a surplus of inflammatory mediators is present in the serum of hemodialysis (HD) patients. Anti-inflammatory counterbalancing mechanisms initiated by interleukin-10 (IL-10) and caspase-8 (Casp-8) appear to be disturbed. Earlier observations let us suppose that translational rather than transcriptional mechanisms are responsible for this effect. Therefore, we investigated the polysome profiling of isolated PBMCs to study gene-specific mRNAs attached to monosomes and polysomes in HD patients (n = 42), patients with lipid disorder and normal renal function (LD, n = 10) and healthy control subjects (CO, n = 9). CRP (C-reactive protein) as a marker of inflammation was significantly elevated in HD and LD patients compared to CO subjects. NGAL (neutrophil-associated lipocalin), a potential marker of kidney disease and inflammation was increased in HD versus LD and CO. LD patients, however, had significantly higher proteosomal IL-10 and Casp-8 activities. LD and HD are two high cardiovascular risk groups with microinflammation. Lower translational activities of IL-10 and Casp-8 mRNAs in HD may be the result of a weak anti-inflammatory response potentially associated with the uremic immune defect.

Review of Precision Medicine and Diagnosis of Neonatal Illness

Background/Objectives: Precision medicine is a state-of-the-art medicine tactic that tailors information about people's genes, environment, and lifestyle to aid the prevention, diagnosis, and treatment of various diseases to provide an overview of the currently available knowledge and applicability of precision medicine in the diagnosis of different cases admitted to the NICU, such as encephalopathies, respiratory distress syndrome of prematurity, hemodynamic instability, acute kidney injury, sepsis, and hyperbilirubinemia. Methods: The authors searched databases, such as PubMed and PubMed Central, for the terms neonatal "precision medicine", "personalized medicine", "genomics", and "metabolomics", all related to precision medicine in the diagnosis of neonatal illness. The related studies were collected. Results: The review highlights the diagnostic approach that serves to implement precision medicine in the NICU and provide precision diagnosis, monitoring, and treatment. Conclusions: In this review, we projected several diagnostic approaches that provide precision identification of health problems among sick neonates with complex illnesses in the NICU; some are noninvasive and available in ordinary healthcare settings, while others are invasive or not feasible or still in ongoing research as machine learning algorithms. Future studies are needed for the wide implementation of artificial intelligence tools in the diagnosis of neonatal illnesses.

Enhanced mortality prediction in pediatric sepsis using NGAL: A comparison with PRISM III scores in critical care settings

Sepsis is a critical condition that disrupts metabolic, physiological, and immune functions, often resulting in severe complications such as multi-organ failure and increased mortality. Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a promising biomarker for infection and inflammation, offering potential advantages for early mortality prediction. This study compared the predictive value of serum NGAL levels with pediatric risk of mortality III (PRISM III) scores in critically ill pediatric patients with sepsis. A prospective cohort study was conducted at a tertiary hospital from September 2022 to March 2023, involving 75 pediatric patients diagnosed with sepsis, septic shock, or multi-organ dysfunction syndrome (MODS), along with 25 healthy controls. Serum NGAL levels were measured within the first hour of PICU admission and analyzed alongside PRISM III scores to evaluate their correlation with mortality and sepsis severity. The results demonstrated that serum NGAL levels were significantly elevated in septic patients compared to controls, with the highest levels observed in those with MODS. NGAL showed greater sensitivity and specificity for predicting mortality than PRISM III scores, with ROC curve analysis revealing that NGAL levels > 599 mg/ml were strongly associated with increased mortality risk (sensitivity 70.4% and specificity 50%). Multivariate analysis confirmed NGAL as an independent predictor of mortality, outperforming PRISM III scores in identifying severe cases.

CONCLUSION

Serum NGAL is a valuable biomarker for early prediction of mortality and sepsis severity in pediatric patients, providing faster and more accurate assessments than PRISM III scores. Its integration into clinical practice may enhance decision-making in pediatric critical care settings, allowing for timely interventions and improved patient outcomes.

WHAT IS KNOWN

• Pediatric risk of mortality III (Prism III) scores is widely used to predict sepsis severity and mortality in pediatric intensive care units, but requiring 12-24 hours to complete. Neutrophil is an established biomarker for inflammation and infection with a potentially anti-pathological value in the neutrophil gelatinus-lipocalin (NGAL) sepsis.

WHAT IS NEW

• Serum NGAL levels, PICU is measured within the first hour of entry, prism III score in pediatric patients in predicting mortality and severity of sepsis. > An NGAL cutoff of 599 mg/mL is significantly associated with mortality risk, which provides a rapid, independent and more immediate immunity tool for important care decision making.

Biomarkers to predict or measure steroid resistance in idiopathic nephrotic syndrome: A systematic review

In this systematic review we have sought to summarise the current knowledge concerning biomarkers that can distinguish between steroid-resistant nephrotic syndrome and steroid-sensitive nephrotic syndrome. Additionally, we aim to select biomarkers that have the best evidence-base and should be prioritised for further research. Pub med and web of science databases were searched using "steroid resistant nephrotic syndrome AND biomarker". Papers published between 01/01/2012 and 10/05/2022 were included. Papers that did not compare steroid resistant and steroid sensitive nephrotic syndrome, did not report sensitivity/specificity or area under curve and reviews/letters were excluded. The selected papers were then assessed for bias using the QUADAS-2 tool. The source of the biomarker, cut off, sensitivity/specificity, area under curve and sample size were all extracted. Quality assessment was performed using the BIOCROSS tool. 17 studies were included, comprising 15 case-control studies and 2 cross-sectional studies. Given the rarity of nephrotic syndrome and difficulty in recruiting large cohorts, case-control studies were accepted despite their limitations. We present a range of candidate biomarkers along with scores relating to the quality of the original publications and the risk of bias to inform future investigations. None of the selected papers stated whether the authors were blinded to the patient's disease when assessing the index test in the cohort. Highlighting a key problem in the field that needs to be addressed. These candidate biomarkers must now be tested with much larger sample sizes. Using new biobanks such as the one built by the NURTuRE-INS team will be very helpful in this regard.

Urinary biomarkers for diagnosing acute kidney injury in sepsis in the emergency department

Background

Development of acute kidney injury (AKI) in patients with sepsis is associated with increased mortality, highlighting the importance of early detection and management. However, baseline creatinine or urine output measurements are required for AKI diagnosis, which can be challenging in emergency departments (EDs). We aimed to evaluate the association between urinary biomarkers and the AKI diagnosis or 30-day survival status in patients with sepsis in the ED.

Methods

This prospective observational study enrolled patients from a single ED. We enrolled adult patients presenting to the ED with symptoms suggestive of infection and an initial quick sequential organ failure assessment score ≥2. Initial urine samples were collected, and urinary biomarkers (dickkopf-3, soluble triggering receptor expressed on myeloid cells-1, kidney injury molecule-1, neutrophil gelatinase-associated lipocalin (NGAL), and tissue inhibitor of metalloproteinases-2 (TIMP-2), and insulin-like growth factor binding protein-7 (IGFBP-7), and TIMP-2 × IGFBP-7) were analyzed using an enzyme-linked immunosorbent assay kit. Multivariable logistic regression models were used to evaluate biomarker performance.

Results

Of 84 patients, 63 (75.0 %) were diagnosed with AKI and 16 (19.0 %) died within 30 days. None of the urinary biomarkers demonstrated significant differences between the survivors and non-survivors. NGAL (p = 0.014) and TIMP-2 × IGFBP-7 (p = 0.027) levels were different between the AKI and non-AKI groups. The multivariable logistic regression model suggested a higher area under the receiver operating characteristic curve for models, including TIMP-2 × IGFBP-7 (from 0.853 to 0.889, p = 0.018).

Conclusion

None of the urinary biomarkers in the initial urine sample demonstrated an independent association with AKI diagnosis or 30-day survival status in patients with sepsis presenting to the ED. Further studies with larger population are necessary to confirm its clinical utility and explore its role.

Determination of Urinary Neutrophil Gelatinase-Associated Lipocalin (uNGAL) Reference Intervals in Healthy Adult and Pediatric Individuals Using a Particle-Enhanced Turbidimetric Immunoassay

Background: The current gold standards for diagnosing acute kidney injury (AKI) are an increase in serum creatinine and a decrease in urine output, which are inadequate for rapid diagnosis. Neutrophil gelatinase-associated lipocalin (NGAL) is a 25-kDa protein produced and secreted by injured kidney tubule epithelial cells, and can serve as an early urinary biomarker for AKI. ProNephro AKI (NGAL) is an immunoassay for the quantitative determination of NGAL in urine (uNGAL) that recently received FDA clearance. A multisite, cross-sectional study was conducted to establish reference intervals for uNGAL in apparently healthy individuals. Methods: Urine samples were collected from apparently healthy individuals aged ≥3 months who met all inclusion criteria and no exclusion criteria. Specimens were temporarily stored at room temperature or 2-8 °C, then transferred into urinalysis tubes before being frozen and shipped for testing. uNGAL testing was performed using the ProNephro AKI (NGAL) immunoassay on a Roche cobas c501 analyzer. Results: Of the 688 individuals screened, 677 were eligible, and 629 (91.4%) of those were deemed evaluable. The 95th and 97.5th percentile uNGAL values for all pediatric participants were below the clinical cutoff of 125 ng/mL. uNGAL values were statistically significantly higher for female vs. male participants in both adult (p = 0.003) and pediatric groups (p < 0.001), while differences were not statistically significant for age, site location, race, or ethnicity. Conclusions: This study provides normal reference intervals for uNGAL with the ProNephro AKI (NGAL) clinical chemistry immunoassay that may be useful for interpreting patient results.

Furosemide stress test to predict acute kidney injury progression in critically ill children

BACKGROUND

Furosemide stress test (FST) is a novel functional biomarker for predicting severe acute kidney injury (AKI); however, pediatric studies are limited.

METHODS

Children 3 months to 18 years of age admitted to the intensive care unit (ICU) of a tertiary care hospital from Nov 2019 to July 2021 were screened and those who developed AKI stage 1 or 2 within 7 days of admission underwent FST (intravenous furosemide 1 mg/kg). Urine output was measured hourly for the next 6 h; a value > 2 ml/kg within the first 2 h was deemed furosemide responsive. Other biomarkers like plasma neutrophil gelatinase-associated lipocalin (NGAL) and proenkephalin (PENK) were also evaluated.

RESULTS

Of the 480 admitted patients, 51 developed AKI stage 1 or 2 within 7 days of admission and underwent FST. Nine of these patients were furosemide non-responsive. Thirteen (25.5%) patients (eight of nine from FST non-responsive group) developed stage 3 AKI within 7 days of FST, nine (17.6%) of whom (seven from non-responsive group) required kidney support therapy (KST). FST emerged as a good biomarker for predicting stage 3 AKI and need for KST with area-under-the-curve (AUC) being 0.93 ± 0.05 (95% CI 0.84-1.0) and 0.96 ± 0.03 (95% CI 0.9-1.0), respectively. FST outperformed NGAL and PENK in predicting AKI stage 3 and KST; however, the combination did not improve the diagnostic accuracy.

CONCLUSIONS

Furosemide stress test is a simple, inexpensive, and robust biomarker for predicting stage 3 AKI and KST need in critically ill children. Further research is required to identify the best FST cut-off in children.

Evolving indications and management patterns in heart - kidney transplantation

PURPOSE OF REVIEW

Dual heart - kidney transplantation (HKT) is an increasingly utilized option for patients with end-stage heart failure and impaired renal function. In 2023, the United Network for Organ Sharing (UNOS) formalized indications for simultaneous heart - kidney transplantation (SHKT) and kidney-after-heart transplantation (KAHT). In light of this landmark effort, we review the evolution in HKT indications, outcomes after SHKT and KAHT in various patient populations, novel considerations in pre and posttransplant management, and areas for future research.

RECENT FINDINGS

The UNOS policy was borne out of retrospective outcome studies suggesting that SHKT is superior to single-organ heart transplantation (HT) in select patients with sufficiently severe renal impairment. KAHT utilization continues to evolve, providing a helpful safety net for HT recipients with irreversible worsening of renal function. Time-limited pretransplant device trials are useful for identifying optimal candidates for HKT, and calcineurin inhibitor-sparing regimens can preserve posttransplant renal function. Explorations into artificial intelligence algorithms and biomarker technology represent interesting future opportunities.

SUMMARY

Recent studies have refined selection and management of dual HKT recipients. The new UNOS policies now provide helpful standardization to the field. Rapid innovation to date has made dual HKT an exciting therapeutic strategy for patients with few options left.

Exploratory testing of functional blood oxygenation level dependent-MRI to image the renoprotective effect of Remote Ischaemic PreConditioning during partial nephrectomy

Urinary biomarker studies in cardiothoracic and kidney-sparing surgery have demonstrated renal protection by Remote Ischaemic PreConditioning (RIPC). RIPC intervention generates cycles of ischaemia and reperfusion of the limbs before the actual ischaemia of the target organ (e.g. kidney) is initiated. This explorative trial aims to investigate whether Blood Oxygenation Level Dependent-MRI (BOLD-MRI) can be a suitable technique to image and quantify the renoprotective effect of RIPC on ischaemia/reperfusion injury (IRI) after partial nephrectomy (PN). Overall, 15 patients were enrolled in this randomized controlled trial. Randomization was 1:1, with RIPC in the intervention arm. Urinary neutrophil gelatinase-associated lipocalin (NGAL), a sensitive biomarker for renal tubular damage was measured preoperatively and for the first 5 days after surgery. Functional BOLD-MRI was successfully performed preoperatively and 48 h after PN in 11 patients. BOLD-MRI uses ∆R2* to express acute tubular damage induced by IRI. The more the ∆R2* values have decreased postoperatively, the more damage the renal tubuli have taken. The cumulative urinary concentration of NGAL in the first 5 postoperative days was significantly lower in the RIPC group (p = 0.02) as compared to the control arm, indicating that the RIPC maneuver performed was effective. The highest difference was seen 6 h after surgery with NGAL being 65% lower in the RIPC arm. IRI of the operated kidney expressed by ∆R2* in BOLD-MRI was 2.1 times less pronounced in the RIPC group as compared to the noRIPC group (∆R2* in % preop/postop RIPC: 14.73/12.57 vs. noRIPC 16.33/11.82, p = 0.36). We were able to demonstrate the potential of BOLD-MRI in measuring IRI. For the first time, it was shown that the renoprotective effects of RIPC can be visualized and measured using BOLD-MRI. Larger studies are required to validate these initial findings.

Serum neutrophil gelatinase-associated lipocalin and cystatin C is associated with blood pressure in ex-preterm children and adolescents

BACKGROUND

As preterm birth is a risk factor for hypertension (HTN), biomarkers for early prediction of HTN in childhood is an emerging need. The aims of the study were to evaluate serum biomarkers in ex-preterm children and examine for associations with office peripheral and central SBP (cSBP), ambulatory BP parameters and pulse wave velocity (PWV).

METHODS

This case-control study included children and adolescents born prematurely (ex-preterms) and at full term (controls). All participants underwent office and ambulatory BP monitoring, assessment of cSBP, PWV and serum biomarkers at the same visit. Neutrophil gelatinase-associated lipocalin (NGAL), matrix metalloproteinase-2, metalloproteinase-9 (MMP-2, MMP-9) and Cystatin C (CysC) were measured using ELISA.

RESULTS

The study population included 52 ex-preterm individuals and 26 controls. Mean age was 10.7 ± 3.6 years. NGAL, MMP-2, MMP-9, and CysC levels were similar between the ex-preterm and the control group. In the ex-preterm group, NGAL is associated with office SBP z score ( β  = 1.007, 95% CI 1.001-0.014, P  = 0.049), CysC with office DBP z score ( β  = 1.003, 95% CI 1.001-0.005, P  = 0.018) and cSBP z score ( β  = 1.003, 95% CI 1.001-0.005, P  = 0.006) independently of age, sex and BMI z score. Among ex-preterm children and adolescents 17% had ambulatory HTN and 31% had white-coat HTN. NGAL levels were higher in ex-preterm children with WCH compared with children with normal BP [57.9 (IQR 50.8) versus 34.6 (IQR 46.2)], P  = 0.018].

CONCLUSION

WCH is common in ex-preterm children and adolescents and is associated with higher NGAL levels and CysC presents positive association with cSBP. The findings in this study provides preliminary evidence that NGAL and CysC may have a role in predicting the risk of developing hypertension later in life. Further studies are warranted.

Prognostic Value of Serum Neutrophil Gelatinase-Associated Lipocalin in Acute Heart Failure: A Meta-Analysis

Background

Neutrophil gelatinase-associated lipocalin (NGAL) is not only a sensitive marker of acute kidney injury but may also be a prognostic marker of acute heart failure (AHF). This study aimed to investigate the relationship between serum NGAL and all-cause death (ACD) and the composite outcome of ACD or AHF readmissions in patients with AHF.

Methods

The Embase, Cochrane Library, and PubMed databases were searched for articles focusing on serum NGAL and ACD and the composite outcome of ACD or AHF readmissions in patients with AHF. The hazard ratios (HRs) were pooled with random-effects models.

Results

The results from 2428 patients from seven studies were pooled in this article. Higher NGAL was relevant to an increased risk of ACD (HR, 1.89; 95% CI, 1.38 to 2.61) and the composite outcome of ACD or AHF readmissions (HR, 2.92; 95% CI, 1.62 to 5.27) in patients with AHF.

Conclusions

Serum NGAL has prognostic value for ACD and the composite outcome of ACD or AHF readmissions in AHF.

The PROSPERO registration

CRD42022322057, https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022322057.

Urine dipstick blood and acute kidney injury in infants undergoing cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass (CPB) is associated with hemolysis and acute kidney injury (AKI). The study aim was to determine if urine dipstick blood in infants after CPB was associated with AKI and urine neutrophil gelatinase-associated lipocalin (NGAL).

METHODS

Infants who underwent CPB at a single center were enrolled prospectively between October 2017 and June 2019. Urine samples prior to CPB and 6 h after CPB cessation were analyzed in batch for NGAL and dipstick blood. AKI was defined using creatinine-based KDIGO criteria within 72 h of CPB. Spearman correlation examined associations between urine dipstick blood and NGAL at each time point. Linear regression estimated the associations between urine dipstick blood and log-transformed NGAL 6 h after CPB. Logistic regression estimated associations and compared discrimination between urine dipstick blood and NGAL for predicting AKI.

RESULTS

At baseline, 7/63 samples (11%) had > trace blood. Six hours after CPB, 62/98 samples (63%) had > trace blood and 26% had 3 + (large) blood. In total, 18/98 (18%) with a 6-h post-CPB sample had postoperative AKI. Urine dipstick blood values correlated with urine NGAL 6 h after CPB (r = 0.52, p < 0.01), but not at baseline (r = 0.06, p = 0.66). Those with 3 + (large) blood on urine dipstick had 6 times higher mean NGAL values compared to those with negative/trace blood (mean ratio 6.6, 95%CI 3.1-14.4, p < 0.01). Those with 3 + (large) blood had 8 times higher odds of AKI (OR 7.99, 95%CI 1.5-41.9, p = 0.01).

CONCLUSIONS

Urine dipstick blood post CPB may be a simple and inexpensive tool to help predict AKI in infants.

Assessment of urine CCL2 as a potential diagnostic biomarker for acute kidney injury and septic acute kidney injury in intensive care unit patients

Acute kidney injury (AKI) is a prevalent and serious condition in the intensive care unit (ICU), associated with significant morbidity and mortality. Septic acute kidney injury (SAKI) contributes substantially to AKI cases in the ICU. However, current diagnostic methods have limitations, necessitating the exploration of novel biomarkers. In this study, we investigated the potential of plasma and urine CCL2 levels as diagnostic markers for AKI and SAKI in 216 ICU patients. Our findings revealed significant differences in plasma (p < 0.01) and urine CCL2 (p < 0.0001) levels between AKI and non-AKI patients in the ICU. Notably, urine CCL2 demonstrated promising predictive value for AKI, exhibiting high specificity and sensitivity (AUC = 0.8976; p < 0.0001). Furthermore, we observed higher urine CCL2 levels in SAKI compared to non-septic AKI (p < 0.001) and urine CCL2 could also differentiate SAKI from non-septic AKI (AUC = 0.7597; p < 0.0001). These results suggest that urine CCL2 levels hold promise as early biomarkers for AKI and SAKI, offering valuable insights for timely intervention and improved management of ICU patients.

Does serum neutrophil gelatinase-associated lipocalin level predict acute kidney injury in patients with acute rhabdomyolysis in the emergency department? A multicentre prospective study

OBJECTIVES

The major complication of rhabdomyolysis is acute kidney injury (AKI), which requires prompt treatment. Currently, few biomarkers are available for the early detection of AKI. Serum neutrophil gelatinase-associated lipocalin (NGAL) has been suggested as an early biomarker for renal ischemia. However, its capacity to predict AKI in patients presenting with rhabdomyolysis in the emergency department (ED) remains unclear. The aim of this study was to evaluate the ability of NGAL to predict 48-hour AKI.

DESIGN

Prospective, multicentre study.

SETTING

Five adult EDs in France from August 2013 to December 2015.

PARTICIPANTS

NGAL levels were measured on ED admission in patients with rhabdomyolysis. A total of 197 patients were enrolled, and 189 (96%) were analysed, of whom 89 (47%) were women. Patients were included if they presented to the ED with rhabdomyolysis and a creatine phosphokinase (CPK) level above 1000 IU/L. Exclusion criteria were pregnancy, presentation with acute coronary syndrome, the need for iodinated contrast, chronic dialysis or recent use of nephrotoxic drugs (within 72 hours prior to the ED visit). Patients who withdrew consent or had AKI due to other causes were also excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was AKI at 48 hours, defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary outcomes included in-hospital mortality, length of hospital stay, admission to intensive care and the need for renal replacement therapy.

RESULTS

Overall, 54 (29%) patients developed AKI by day 2. The area under the ROC curve (AUC-ROC) for NGAL in predicting AKI on day 2 was 0.60 (95% CI 0.51 to 0.70), with an optimal cut-off of 129 ng/mL. The sensitivity was 0.65, and specificity was 0.50. After adjustment for CPK levels, age, sex and oxygen saturation, the AUC-ROC for predicting AKI on day 2 increased slightly to 0.64 (95% CI 0.54 to 0.74).

CONCLUSION

NGAL has limited ability to predict day 2 AKI in patients presenting with acute rhabdomyolysis in the ED.

TRAIL REGISTRATION NUMBER

NCT01544231.Comité de Protection des Personnes Sud Méditerranée III n°2011-A01059-32.

Past, present, and future biomarkers of kidney function and injury: The relationship with antibiotics

Routinely used kidney biomarkers of injury and function such as serum creatinine and urine albumin to creatinine ratio, are neither sensitive nor specific. Future biomarkers are being developed for clinical use and have already been included in guidance from groups such as the U.S. Food and Drug Administration and the Predictive Safety Testing Consortium. These biomarkers have important implications for early identification of kidney injury and more accurate measurement of kidney function. Many antibiotics are either eliminated by the kidney or can cause clinically significant nephrotoxicity. As a result, clinicians should be familiar with new biomarkers of kidney function and injury, their place in clinical practice, and applications for antibiotic dosing.

Evaluation of Neutrophil Gelatinase-Associated Lipocalin Levels in Children With Febrile Seizures: A Case-Control Study

Febrile seizure (FS) is a common pediatric neurological disorder, which may be associated with hypoxia and kidney injury. We aimed to investigate serum levels of neutrophil gelatinase-associated lipocalin (NGAL) in children with FS. This case-control study included 50 children with FS, 50 febrile controls (FCs), and 50 healthy controls (HCs). We measured serum NGAL levels using a human enzyme-linked immunosorbent assay. Serum NGAL/creatinine values showed significant differences within and between study groups with the highest levels for the FS group (1382 ± 215), the middle for FCs (1133 ± 129), and the lowest for HCs (857 ± 97). None of the study participants had abnormal serum creatinine levels, and their values were comparable among the 3 study groups. In conclusion, children with FS may have increased serum NGAL levels despite normal serum creatinine, indicating that FS could contribute to subclinical renal injury without significant loss of excretory kidney function.

Transition from acute kidney injury to chronic kidney disease in a long-term murine model of Shiga toxin-induced hemolytic-uremic syndrome

Introduction

Up to 40% of patients with typical hemolytic-uremic syndrome (HUS), characterized by microangiopathic hemolytic anemia and acute kidney injury (AKI), develop long-term consequences, most prominently chronic kidney disease (CKD). The transition from AKI to CKD, particularly in the context of HUS, is not yet fully understood. The objective of this study was to establish and characterize a Shiga toxin (Stx)-induced long-term HUS model to facilitate the study of mechanisms underlying the AKI-to-CKD transition.

Methods

C57BL/6J mice were subjected to 5, 10, 15, or 20 ng/kg Stx on days 0, 3, and 6 of the experiment and were sacrificed on day 14 or day 21 to identify the critical time of turnover from the acute to the chronic state of HUS disease.

Results

Acute disease, indicated by weight loss, plasma neutrophil gelatinase-associated lipocalin (NGAL) and urea, and renal neutrophils, diminished after 14 days and returned to sham level after 21 days. HUS-associated hemolytic anemia transitioned to non-hemolytic microcytic anemia along with unchanged erythropoietin levels after 21 days. Renal cytokine levels indicated a shift towards pro-fibrotic signaling, and interstitial fibrosis developed concentration-dependently after 21 days. While Stx induced the intrarenal invasion of pro-inflammatory M1 and pro-fibrotic M2 macrophages after 14 days, pro-fibrotic M2 macrophages were the dominant phenotype after 21 days.

Conclusion

In conclusion, we established and characterized the first Stx-induced long-term model of HUS. This tool facilitates the study of underlying mechanisms in the early AKI-to-CKD transition following HUS and allows the testing of compounds that may protect patients with AKI from developing subsequent CKD.

Intraoperative Oxygen Treatment, Oxidative Stress, and Organ Injury Following Cardiac Surgery: A Randomized Clinical Trial

Importance

Liberal oxygen (hyperoxia) is commonly administered to patients during surgery, and oxygenation is known to impact mechanisms of perioperative organ injury.

Objective

To evaluate the effect of intraoperative hyperoxia compared to maintaining normoxia on oxidative stress, kidney injury, and other organ dysfunctions after cardiac surgery.

Design, Setting, and Participants

This was a participant- and assessor-blinded, randomized clinical trial conducted from April 2016 to October 2020 with 1 year of follow-up at a single tertiary care medical center. Adult patients (>18 years) presenting for elective open cardiac surgery without preoperative oxygen requirement, acute coronary syndrome, carotid stenosis, or dialysis were included. Of 3919 patients assessed, 2501 were considered eligible and 213 provided consent. Of these, 12 were excluded prior to randomization and 1 following randomization whose surgery was cancelled, leaving 100 participants in each group.

Interventions

Participants were randomly assigned to hyperoxia (1.00 fraction of inspired oxygen [FiO2]) or normoxia (minimum FiO2 to maintain oxygen saturation 95%-97%) throughout surgery.

Main Outcomes and Measures

Participants were assessed for oxidative stress by measuring F2-isoprostanes and isofurans, for acute kidney injury (AKI), and for delirium, myocardial injury, atrial fibrillation, and additional secondary outcomes. Participants were monitored for 1 year following surgery.

Results

Two hundred participants were studied (median [IQR] age, 66 [59-72] years; 140 male and 60 female; 82 [41.0%] with diabetes). F2-isoprostanes and isofurans (primary mechanistic end point) increased on average throughout surgery, from a median (IQR) of 73.3 (53.1-101.1) pg/mL at baseline to a peak of 85.5 (64.0-109.8) pg/mL at admission to the intensive care unit and were 9.2 pg/mL (95% CI, 1.0-17.4; P = .03) higher during surgery in patients assigned to hyperoxia. Median (IQR) change in serum creatinine (primary clinical end point) from baseline to postoperative day 2 was 0.01 mg/dL (-0.12 to 0.19) in participants assigned hyperoxia and -0.01 mg/dL (-0.16 to 0.19) in those assigned normoxia (median difference, 0.03; 95% CI, -0.04 to 0.10; P = .45). AKI occurred in 21 participants (21%) in each group. Intraoperative oxygen treatment did not affect additional acute organ injuries, safety events, or kidney, neuropsychological, and functional outcomes at 1 year.

Conclusions

Among adults receiving cardiac surgery, intraoperative hyperoxia increased intraoperative oxidative stress compared to normoxia but did not affect kidney injury or additional measurements of organ injury including delirium, myocardial injury, and atrial fibrillation.

Trial Registration

ClinicalTrials.gov Identifier: NCT02361944.

Neutrophil Gelatinase-Associated Lipocalin (NGAL) as a Predictor for Sepsis Mortality in Children Admitted to Pediatric Intensive Care Unit (PICU): A Comparison With Prothrombin Time/International Normalized Ratio (PT/INR) and Urea/Creatinine Ratio

Background Sepsis is the primary cause of death in children, and it is crucial to identify patients at high risk of mortality early on in order to provide intensive monitoring and management in the Pediatric Intensive Care Unit (PICU). Objective The objective of this study was to assess the predictive value of routinely used sepsis indicators, including neutrophil gelatinase-associated lipocalin (NGAL), urea to creatinine ratio (urea/Cr), and prothrombin time and international normalized ratio (PT/INR), in predicting death in critically unwell children. Patients and methods A total of 75 children were included in the research conducted at the PICU of Minia University. Among them, 21 (28%) were released as survivors, while the remaining 54 (72%) unfortunately passed away. All participating children were subjected to serum NGAL, urea/Cr, and PT/INR measurements during the first 24 hours of hospitalization. The severity of sepsis was assessed using the Pediatric Risk of Mortality (PRISM) III score. Results The NGAL, prothrombin, urea, and creatinine levels were considerably elevated in the group of individuals who died compared to those who survived (P < 0.001, 0.007, 0.028, and 0.032, respectively). However, no significant difference was found between survivors and deceased children in terms of the PT/INR ratio and urea/Cr ratio. When predicting mortality, NGAL with a cutoff point of more than 990 had a sensitivity of 100% and a specificity of 35%. Similarly, the PRISM score with a cutoff point greater than 18 had a sensitivity of 83.3% and a specificity of 42.9%. Conclusion Serum NGAL is reliable in the early prediction of mortality in children admitted with sepsis.

Urinary Complement C3 and Vitamin D-Binding Protein Predict Adverse Outcomes in Patients with Acute Kidney Injury after Cardiac Surgery

INTRODUCTION

Acute kidney injury (AKI) is associated with adverse outcomes, including death and dialysis. The goal of this study was to identify prognostic biomarkers of AKI that could be used across multiple phenotypes of AKI and across different species.

METHODS

Liquid chromatography/tandem mass spectrometry analysis of urine samples from three species (human, rat, and mouse) and four etiologies of AKI identified five potential biomarkers, of which two were validated, complement C3 and vitamin D-binding protein, in a cohort of 157 patients that developed AKI following cardiothoracic surgery. We studied the relationship between the biomarker's concentration in the urine and the development of a composite primary endpoint (stage 3 AKI within 10 days or death within 30 days).

RESULTS

Of the 153 patients who developed AKI following cardiovascular surgery, 17 met the combined primary outcome. The median concentration of urine complement C3 adjusted to urine creatinine had the best predictive value and was significantly higher in the primary outcome group than in the controls. Similarly, the median concentration of vitamin D-binding protein was higher in the primary outcome group.

CONCLUSIONS

The studies provide proof in principle that cross-species discovery analyses could be a valuable tool for identifying novel prognostic biomarkers in AKI. Urine complement C3 and vitamin D-binding protein could be promising early predictors of adverse outcomes in patients who develop AKI after cardiac surgery.

Contrast-Enhanced Ultrasound (CEUS) and Ultra-Microangiography (UMA) in Critically Ill Children with Acute Kidney Injury

Acute kidney injury (AKI) is an acute condition of impaired kidney function with decreased glomerular filtration rate, which results in dysregulation in volume, electrolyte, and acid-base equilibrium. AKI can be a life-threatening condition and can also lead to chronic kidney disease. It is important to diagnose AKI early in the course of the disease or to predict its development, as this can influence therapeutic decisions, outcome, and, consequently, the prognosis. In clinical practice, an elevated serum creatinine concentration remains the most common laboratory indicator for diagnosing AKI. However, due to the delay in its rise, creatinine levels are often insensitive and inaccurate for early diagnosis. Novel biomarkers of kidney tubular injury and the renal angina index have shown promise in predicting AKI earlier and more accurately. Contrast-enhanced ultrasonography (CEUS) and ultra-microangiography (UMA) are radiological methods that can quantify renal microperfusion and may be able to predict the development of AKI. They have not yet been used for quantifying renal perfusion in children with risk factors for developing AKI. Further research is needed to compare these sonographic techniques with the renal angina index and emerging kidney injury biomarkers for predicting acute kidney injury (AKI) in both children and adults.

Lactated Ringers, albumin and mannitol as priming during cardiopulmonary bypass reduces pulmonary edema in rats compared with hydroxyethyl starch

BACKGROUND

Endothelial disorders with edema formation and microcirculatory perfusion disturbances are common in cardiac surgery with cardiopulmonary bypass (CPB) and contribute to disturbed tissue oxygenation resulting in organ dysfunction. Albumin is protective for the endothelium and could be a useful additive to CPB circuit priming. Therefore, this study aimed to compare organ edema and microcirculatory perfusion in rats on CPB primed with lactated Ringers, albumin and mannitol (LR/albumin/mannitol) compared to 6% hydroxyethyl starch (HES).

RESULTS

Male rats were subjected to 75 min of CPB primed with either LR/albumin/mannitol or with 6% HES. Renal and lung edema were determined by wet/dry weight ratio. Pulmonary wet/dry weight ratio was lower in rats on CPB primed with LR/albumin/mannitol compared to HES (4.77 [4.44-5.25] vs. 5.33 [5.06-6.33], p = 0.032), whereas renal wet/dry weight ratio did not differ between groups (4.57 [4.41-4.75] vs. 4.51 [4.47-4.73], p = 0.813). Cremaster microcirculatory perfusion was assessed before, during and after CPB with intravital microscopy. CPB immediately impaired microcirculatory perfusion compared to baseline (LR/albumin/mannitol: 2 [1-7] vs. 14 [12-16] vessels per recording, p = 0.008; HES: 4 [2-6] vs. 12 [10-13] vessels per recording, p = 0.037), which persisted after weaning from CPB without differences between groups (LR/albumin/mannitol: 5 [1-9] vs. HES: 1 [0-4], p = 0.926). In addition, rats on CPB primed with LR/albumin/mannitol required less fluids to reach sufficient flow rates (0.5 [0.0-5.0] mL vs. 9 [4.5-10.0], p < 0.001) and phenylephrine (20 [0-40] µg vs. 90 [40-200], p = 0.004). Circulating markers for inflammation (interleukin 6 and 10), adhesion (ICAM-1), glycocalyx shedding (syndecan-1) and renal injury (NGAL) were determined by ELISA or Luminex. Circulating interleukin-6 (16 [13-25] vs. 33 [24-51] ng/mL, p = 0.006), interleukin-10 (434 [295-782] vs. 2120 [1309-3408] pg/ml, p < 0.0001), syndecan-1 (5 [3-7] vs. 15 [11-16] ng/mL, p < 0.001) and NGAL (555 [375-1078] vs. 2200 [835-3671] ng/mL, p = 0.008) were lower in rats on CPB primed with LR/albumin/mannitol compared to HES.

CONCLUSION

CPB priming with LR, albumin and mannitol resulted in less pulmonary edema, renal injury, inflammation and glycocalyx degradation compared to 6% HES. Furthermore, it enhanced hemodynamic stability compared with HES. Further research is needed to explore the specific role of albumin as a beneficial additive in CPB priming.

Clinical Utility of LC-MS/MS for Blood Myo-Inositol in Patients with Acute Kidney Injury and Chronic Kidney Disease

BACKGROUND

Diagnosing acute kidney injury (AKI) and chronic kidney disease (CKD) relies on creatinine, which lacks optimal diagnostic sensitivity. The kidney-specific proximal tubular enzyme myo-inositol oxygenase (MIOX) catalyzes the conversion of myo-inositol (MI) to D-glucuronic acid. We hypothesized that proximal tubular damage, which occurs in AKI and CKD, will decrease MIOX activity, causing MI accumulation. To explore this, we developed an LC-MS/MS assay to quantify plasma MI and assessed its potential in identifying AKI and CKD patients.

METHODS

MI was quantified in plasma from 3 patient cohorts [normal kidney function (n = 105), CKD (n = 94), and AKI (n = 54)]. The correlations between MI and creatinine were determined using Deming regression and Pearson correlation and the impact of age, sex, and ethnicity on MI concentrations was assessed. Receiver operating characteristic curve analysis was employed to evaluate MI diagnostic performance.

RESULTS

In volunteers with normal kidney function, the central 95th percentile range of plasma MI concentrations was 16.6 to 44.2 µM. Age, ethnicity, and sex showed minimal influence on MI. Patients with AKI and CKD exhibited higher median MI concentrations [71.1 (25th percentile: 38.2, 75th percentile: 115.4) and 102.4 (77, 139.5) µM], respectively. MI exhibited excellent sensitivity (98.9%) and specificity (100%) for diagnosing CKD. In patients with AKI, MI increased 32.9 (SD 16.8) h before creatinine.

CONCLUSIONS

This study unveils MI as a potential renal biomarker, notably elevated in plasma during AKI and CKD. Plasma MI rises 33 h prior to serum creatinine, enabling early AKI detection. Further validation and exploration of MI quantitation in kidney disease diagnosis is warranted.

Assessment of cell cycle arrest biomarkers and neutrophil gelatinase-associated lipocalin to distinguish acute kidney injury from other diseases in dogs

BACKGROUND

Cell cycle arrest biomarkers (tissue inhibitor of metalloproteinase-2 [uTIMP-2] and insulin-like growth factor binding protein 7 [uIGFBP7]), and neutrophil gelatinase-associated lipocalin (NGAL) variables are valuable biomarkers for early diagnosis of acute kidney injury (AKI) in people.

OBJECTIVES

To evaluate uTIMP-2, uIGFBP7, fractional excretion of NGAL (FeNGAL), and urinary to serum NGAL ratio (u/sNGAL) in healthy dogs, dogs with AKI, dogs with chronic kidney disease (CKD), and critically ill (CI) dogs.

ANIMALS

Forty-two client-owned dogs (healthy, n = 10; AKI, n = 11; CKD, n = 11; CI, n = 10).

METHODS

Prospective, observational study. After assessment of routine renal biomarkers, stress (uTIMP-2, uIGFBP7) and damage (NGAL) biomarkers were measured, using ELISA kits, and normalized to urinary creatinine (uCr).

RESULTS

Normalized uTIMP-2 and [uTIMP-2] × [uIGFBP7]/uCr were significantly higher in the AKI group (median 151.9 [range, 2.2-534.2] and 62.9 [1.1-266.8] pg/mL respectively), compared to healthy dogs (0.3 [0.2-74.7]; P < .001 and 0.16 [0.1-58.1] pg/mL; P < .001), dogs with CKD (0.7 [0.3-742.5]; P = .04 and 0.37 [0.2-180.1] pg/mL; P = .03) and CI dogs (1.9 [0.2-37.0]; P = .03 and 0.8 [0.1-16.1] pg/mL; P = .02). Fractional excretion of NGAL was significantly higher in dogs with AKI (54.17 [7.93-155.32] %), than in healthy (0.03 [0.01-0.21] %; P < .001) and CI dogs (3.05 [0.05-28.86] %; P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Normalized uTIMP-2, [uTIMP-2] × [uIGFBP7]/uCr, and FeNGAL can be valuable renal biomarkers for early diagnosis of AKI in dogs.

A Highly Sensitive Lateral-Flow Strip Using Latex Microspheres to Detect NGAL in Urine Samples

The incidence of kidney disease is increasing worldwide. Rapid and cost-effective approaches for early detection help prevent this disease. Neutrophil gelatinase-associated lipocalin protein (NGAL) is a novel biomarker for acute kidney injury (AKI) and chronic kidney disease (CKD). We aimed to develop a lateral flow strip (LFS) based on a lateral flow immunoassay method (LFIA), using latex microspheres (LMs) as a color labeling to detect NGAL in urine. The performance and potential of the developed LMs-LFS at a point-of-care (POC) testing were evaluated. The results showed that LMs-LFS successfully detected urinary NGAL within 15 min with high specificity without cross-reactivity to or interference from other endogenous substances in urine. The visual limit of detection (vLOD) was 18.75 ng/mL, and the limit of detection (LOD) was 1.65 ng/mL under the optimum condition. The LMs-LFS developed in this study showed a high correlation with the enzyme-linked immunosorbent assay (ELISA) method (R 2 = 0.973, n = 60 urine specimens) for detecting NGAL in urine. The LMs-LFS remained stable for at least six months at room temperature. The LMs-LFS can be a rapid, sensitive, and specific tool for the diagnosis and follow-up of renal disorders at the POC.

Protective effect of β-sitosterol against high-fructose diet-induced oxidative stress, and hepatorenal derangements in growing female sprague-dawley rats

BACKGROUND

Chronic consumption of a high-fructose diet causes oxidative stress that compromises kidney and liver health. β-sitosterol (Bst), a phytosterol, is a functional nutrient with health benefits. β-sitosterol antioxidant activity protects the liver and kidney from ROS-mediated damage and lipid peroxidation. We evaluated the potential renoprotective and hepatoprotective effects of orally administrated β-sitosterol in high-fructose diet-fed growing female rats. Thirty-five 21-day old female Sprague-Dawley rat pups were randomly assigned to and administered the following treatments for 12 weeks: group I- standard rat chow (SRC) + plain drinking water (PW) + plain gelatine cube (PC); group II- SRC + 20% w/v fructose solution (FS) as drinking fluid + PC; group III- SRC + FS + 100 mg/kg body mass (BM) fenofibrate in gelatine cube; group IV- SRC + FS + 20 mg/kg BM β-sitosterol gelatine cube (Bst) and group V- SRC + PW + Bst. The rats were fasted overnight, weighed then euthanised. Blood was collected, centrifuged and plasma harvested. Livers and kidneys were excised, weighed and samples preserved for histological assessments. Plasma biomarkers of oxidative stress, liver and kidney function and renal tubular injury were assessed.

RESULTS

High fructose diet fed rats had increased plasma KIM-1, NGAL (p < 0.001) and MDA levels (p < 0.05). Dietary fructose caused microvesicular and macrovesicular steatosis, and reduced glomerular density, Bowman's capsule area and urinary space. β-sitosterol protected against the high-fructose diet-induced hepatic steatosis and glomerular disturbances without adverse effects on liver and kidney function.

CONCLUSIONS

β-sitosterol, as a dietary supplement, could potentially be exploited to prevent high-fructose diet-induced NAFLD and to protect against high-fructose diet-induced renal tubular injury.

Detection strip of anti-NGAL antibody coupled with fluorescent microspheres-A novel tool for reliable and accurate prediction of renal injury

OBJECTIVE

Neutrophil gelatinase-associated lipocalin (NGAL) has been identified by the International Nephrology Association (INA) as a promising biomarker for the early evaluation of renal injury. This study aimed to develop and evaluate NGAL test strips as a rapid, simple, and economical method for the early diagnosis of acute kidney injury (AKI).

METHODS

Recombinant prokaryotic expression vectors, purified NGAL protein, and anti-NGAL monoclonal antibodies were prepared. NGAL test strips were developed, and serum samples were collected from healthy individuals and patients with early-stage kidney injury at the Third Affiliated Hospital of Sun Yat-sen University between January 2023 and May 2024. Samples were tested using both the self-made strips and commercially available reagents.

RESULTS

The NGAL test strip comprised a conjugate pad containing 0.2 μL of fluorescent microspheres conjugated with anti-NGAL monoclonal antibody (McAb7#), a test line containing 1 mg/mL of a different anti-NGAL monoclonal antibody (McAb3#), and a control line containing 0.5 mg/mL of goat anti-mouse IgG. The test utilized 60 μL of sample (30 μL serum diluted with 30 μL of sample diluent) and was completed within 15 min at 25 °C and 35 %-85 % relative humidity. The developed strip accurately detected NGAL, demonstrating good linearity within the range of 0-160 ng/mL (R2 = 0.9943). The sensitivity and specificity of the NGAL strip for AKI diagnosis were 86.1 % and 78.8 %, respectively, comparable to the performance of commercially available testing reagents.

CONCLUSION

The developed test strip, utilizing anti-NGAL antibodies coupled with fluorescent microspheres, effectively detected trace amounts of NGAL protein in serum samples.

Urinary NGAL in gastrointestinal diseases can be used as an indicator of early infection in addition to acute kidney injury marker

Background and Aim

Neutrophil gelatinase-associated lipocalin (NGAL) is characterized by increased expression before the rise in serum creatinine and has been used as a biomarker for the early prediction of acute kidney injury (AKI). However, there have been no comprehensive analyses of its significance in gastrointestinal diseases. This study aimed to analyze the usefulness of measuring urinary NGAL levels in patients with gastrointestinal diseases.

Methods

This study included 171 patients with a wide range of gastrointestinal diseases. Urinary NGAL levels were measured in all patients within 24 h of admission and 72 h later.

Results

Urinary NGAL levels were higher in patients with acute pancreatitis and acute cholangitis/cholecystitis than in those with other diseases. Although lower than in these diseases, urinary NGAL tends to be higher in inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, as well as in acute and chronic liver diseases, and is higher in liver cirrhosis as the Child-Pugh grade increases. Furthermore, we found that the group with higher urinary NGAL levels, which continued to increase over time, had worse hospital stays and prognosis.

Conclusion

Urinary NGAL could be used as an indicator of infectious diseases rather than an indicator of AKI in inflammatory bowel diseases and cirrhosis, and could predict the prognosis of patients with gastrointestinal diseases.

Artificial intelligence in early detection and prediction of pediatric/neonatal acute kidney injury: current status and future directions

Acute kidney injury (AKI) has a significant impact on the short-term and long-term clinical outcomes of pediatric and neonatal patients, and it is imperative in these populations to mitigate the pathways leading to AKI and be prepared for early diagnosis and treatment intervention of established AKI. Recently, artificial intelligence (AI) has provided more advent predictive models for early detection/prediction of AKI utilizing machine learning (ML). By providing strong detail and evidence from risk scores and electronic alerts, this review outlines a comprehensive and holistic insight into the current state of AI in AKI in pediatric/neonatal patients. In the pediatric population, AI models including XGBoost, logistic regression, support vector machines, decision trees, naïve Bayes, and risk stratification scores (Renal Angina Index (RAI), Nephrotoxic Injury Negated by Just-in-time Action (NINJA)) have shown success in predicting AKI using variables like serum creatinine, urine output, and electronic health record (EHR) alerts. Similarly, in the neonatal population, using the "Baby NINJA" model showed a decrease in nephrotoxic medication exposure by 42%, the rate of AKI by 78%, and the number of days with AKI by 68%. Furthermore, the "STARZ" risk stratification AI model showed a predictive ability of AKI within 7 days of NICU admission of AUC 0.93 and AUC of 0.96 in the validation and derivation cohorts, respectively. Many studies have reported the superiority of using biomarkers to predict AKI in pediatric patients and neonates as well. Future directions include the application of AI along with biomarkers (NGAL, CysC, OPN, IL-18, B2M, etc.) in a Labelbox configuration to create a more robust and accurate model for predicting and detecting pediatric/neonatal AKI.

A Multimodal Fuzzy Approach in Evaluating Pediatric Chronic Kidney Disease Using Kidney Biomarkers

Chronic kidney disease (CKD) is one of the most important causes of chronic pediatric morbidity and mortality and places an important burden on the medical system. Current diagnosis and progression monitoring techniques have numerous sensitivity and specificity limitations. New biomarkers for monitoring CKD progression have been assessed. Neutrophil gelatinase-associated lipocalin (NGAL) has had some promising results in adults, but in pediatric patients, due to the small number of patients included in the studies, cutoff values are not agreed upon. The small sample size also makes the statistical approach limited. The aim of our study was to develop a fuzzy logic approach to assess the probability of pediatric CKD progression using both NGAL (urinary and plasmatic) and routine blood test parameters (creatinine and erythrocyte sedimentation rate) as input data. In our study, we describe in detail how to configure a fuzzy model that can simulate the correlations between the input variables ESR, NGAL-P, NGAL-U, creatinine, and the output variable Prob regarding the prognosis of the patient's evolution. The results of the simulations on the model, i.e., the correlations between the input and output variables (3D graphic presentations) are explained in detail. We propose this model as a tool for physicians which will allow them to improve diagnosis, follow-up, and interventional decisions relative to the CKD stage. We believe this innovative approach can be a great tool for the clinician and validates the feasibility of using a fuzzy logic approach in interpreting NGAL biomarker results for CKD progression.

Urinary biomarkers in diabetic nephropathy

Diabetic nephropathy (DN), a significant consequence of diabetes, is associated with adverse cardiovascular and renal disease as well as mortality. Although microalbuminuria is considered the best non-invasive marker for DN, better predictive markers are needed of sufficient sensitivity and specificity to detect disease in general and in early disease specifically. Even prior to appearance of microalbuminuria, urinary biomarkers increase in diabetics and can serve as accurate nephropathy biomarkers even in normoalbuminuria. In this review, a number of novel urine biomarkers including those reflecting kidney damage caused by glomerular/podocyte damage, tubular damage, oxidative stress, inflammation, and intrarenal renin-angiotensin system activation are discussed. Our review also includes emerging biomarkers such as urinary microRNAs. These short noncoding miRNAs regulate gene expression and could be utilized to identify potential novel biomarkers in DN development and progression. .

Biomarkers of chronic kidney disease in older individuals: navigating complexity in diagnosis

Chronic kidney disease (CKD) in older individuals is a matter of growing concern in the field of public health across the globe. Indeed, prevalence of kidney function impairment increases with advancing age and is often exacerbated by age-induced modifications of kidney function, presence of chronic diseases such as diabetes, hypertension, and cardiovascular disorders, and increased burden related to frailty, cognitive impairment and sarcopenia. Accurate assessment of CKD in older individuals is crucial for timely intervention and management and relies heavily on biomarkers for disease diagnosis and monitoring. However, the interpretation of these biomarkers in older patients may be complex due to interplays between CKD, aging, chronic diseases and geriatric syndromes. Biomarkers such as serum creatinine, estimated glomerular filtration rate (eGFR), and albuminuria can be significantly altered by systemic inflammation, metabolic changes, and medication use commonly seen in this population. To overcome the limitations of traditional biomarkers, several innovative proteins have been investigated as potential, in this review we aimed at consolidating the existing data concerning the geriatric aspects of CKD, describing the challenges and considerations in using traditional and innovative biomarkers to assess CKD in older patients, highlighting the need for integration of the clinical context to improve biomarkers' accuracy.

Disposable label-free electrochemical immunosensor based on gold nanoparticles-Prussian blue for neutrophil gelatinase-associated lipocalin detection in urine samples

Neutrophil gelatinase-associated lipocalin (NGAL) is a remarkable biomarker for assessing acute kidney injury. In this study, we developed a novel label-free NGAL electrochemical immunosensor based on gold nanoparticles (AuNPs) and Prussian blue (PB) without an external mediator. The AuNPs-PB based immunosensor was fabricated on a custom gold-electrode (AuE)-based polypropylene (PP) substrate. We systematically assessed and optimized key experimental parameters, including the process of AuNPs-PB electrodeposition, antibody concentration, and incubation time. The immunosensor response toward NGAL was determined using differential pulse voltammetry, where the decrease in the oxidation current response of the PB redox probe correlating with the increase in NGAL concentration. Our results demonstrated that the synergistic benefits of both AuNPs and PB significantly improved electrochemical activity for NGAL detection and provided a highly stable sensor across a range of pH values. The label-free immunosensor exhibited two linear ranges: 0.10-1.40 ng mL-1 and 1.40-25.0 ng mL-1, with a low detection limit of 0.094 ng mL-1. The developed NGAL immunosensor displayed high selectivity and excellent reproducibility. Furthermore, NGAL detection was completed within 30 min and the immunosensor exhibited storage stability for six weeks. Notably, NGAL levels determined in human urine samples using this developed label-free immunosensor showed good agreement with the results obtained from the enzyme-linked immunosorbent assay. This novel label-free NGAL immunosensor provides great potential in developing NGAL point-of-care testing applications.

Multi-omics and imaging mass cytometry characterization of human kidneys to identify pathways and phenotypes associated with impaired kidney function

Despite the recent advances in our understanding of the role of lipids, metabolites, and related enzymes in mediating kidney injury, there is limited integrated multi-omics data identifying potential metabolic pathways driving impaired kidney function. The limited availability of kidney biopsies from living donors with acute kidney injury has remained a major constraint. Here, we validated the use of deceased transplant donor kidneys as a good model to study acute kidney injury in humans and characterized these kidneys using imaging and multi-omics approaches. We noted consistent changes in kidney injury and inflammatory markers in donors with reduced kidney function. Neighborhood and correlation analyses of imaging mass cytometry data showed that subsets of kidney cells (proximal tubular cells and fibroblasts) are associated with the expression profile of kidney immune cells, potentially linking these cells to kidney inflammation. Integrated transcriptomic and metabolomic analysis of human kidneys showed that kidney arachidonic acid metabolism and seven other metabolic pathways were upregulated following diminished kidney function. To validate the arachidonic acid pathway in impaired kidney function we demonstrated increased levels of cytosolic phospholipase A2 protein and related lipid mediators (prostaglandin E2) in the injured kidneys. Further, inhibition of cytosolic phospholipase A2 reduced injury and inflammation in human kidney proximal tubular epithelial cells in vitro. Thus, our study identified cell types and metabolic pathways that may be critical for controlling inflammation associated with impaired kidney function in humans.

Perioperative Acute Renal Injury: Revisiting Pathophysiology

BACKGROUND

Acute renal dysfunction and subsequent acute renal failure after cardiac surgery are associated with high mortality and morbidity. Early therapeutic or preventive intervention is hampered by the lack of an early biomarker for acute renal injury. Recent studies showed that urinary neutrophil gelatinase-associated lipocalin (NGAL or lipocalin 2) is upregulated early (within 1 to 3 h) after murine renal injury and in pediatric acute renal dysfunction after cardiac surgery. The authors hypothesized that postoperative urinary NGAL concentrations are increased in adult patients developing acute renal dysfunction after cardiac surgery compared with patients without acute renal dysfunction.

METHODS

After institutional review board approval, 81 cardiac surgical patients were prospectively studied. Urine samples were collected immediately before incision and at various time intervals after surgery for NGAL analysis by quantitative immunoblotting. Acute renal dysfunction was defined as peak postoperative serum creatinine increase by 50% or greater compared with preoperative serum creatinine.

RESULTS

Sixteen of 81 patients (20%) developed postoperative acute renal dysfunction, and the mean urinary NGAL concentrations in patients who developed acute renal dysfunction were significantly higher early after surgery (after 1 h, mean ± SD, 4,195 ± 6,520 vs. 1,068 ± 2,129 ng/ml; P < 0.01) compared with patients who did not develop acute renal dysfunction. Mean urinary NGAL concentrations continued to increase and remained significantly higher at 3 and 18 h after cardiac surgery in patients with acute renal dysfunction. In contrast, urinary NGAL in patients without acute renal dysfunction decreased rapidly after cardiac surgery.

CONCLUSIONS

Patients developing postoperative acute renal dysfunction had significantly higher urinary NGAL concentrations early after cardiac surgery. Urinary NGAL may therefore be a useful early biomarker of acute renal dysfunction after cardiac surgery. These findings may facilitate the early detection of acute renal injury and potentially prevent progression to acute renal failure.

Tachycardia and Acute Kidney Injury among Critically Ill Patients with Sepsis: A Prospective Observational Study

INTRODUCTION

Tachycardia caused by sympathetic overactivity impairs myocardial function and raises septic patients' mortality. This study examined whether tachycardia is associated with acute kidney injury (AKI) period-prevalence among critically ill patients with and without sepsis.

METHODS

In 328 patients (119 sepsis and 209 non-sepsis) admitted to our intensive care unit (ICU), we assessed heart rate at ICU admission, plasma neutrophil gelatinase-associated lipocalin (NGAL) and N-terminal pro-B-type natriuretic peptide, and urinary L-type fatty acid-binding protein and N-acetyl-β-d-glucosaminidase (NAG) at 0 and 48 h after admission. Tachycardia was defined as a heart rate above 100 beats/min.

RESULTS

Tachycardia was independently correlated with AKI prevalence during the first week after ICU admission in the septic patients, but not in the non-septic patients. A dose-dependent increase in AKI period-prevalence was observed across ascending heart rate ranges. Furthermore, we discovered a dose-dependent increase in renal biomarker-positive patients regarding plasma NGAL and urinary NAG over increasing heart rate ranges 48 h after admission.

CONCLUSION

The findings revealed an independent relationship between tachycardia and AKI prevalence during the first week of ICU in septic patients. Heart rate was found to have a dose-dependent effect on AKI prevalence and renal insult monitored by biomarkers.

Acute Kidney Injury in Neonatal Intensive Care Unit: Epidemiology, Diagnosis and Risk Factors

Acute kidney injury (AKI) is associated with long-term consequences and poor outcomes in the neonatal intensive care unit. Its precocious diagnosis represents one of the hardest challenges in clinical practice due to the lack of sensitive and specific biomarkers. Currently, neonatal AKI is defined with urinary markers and serum creatinine (sCr), with limitations in early detection and individual treatment. Biomarkers and risk factor scores were studied to predict neonatal AKI, to early identify the stage of injury and not the damage and to anticipate late increases in sCr levels, which occurred when the renal function already began to decline. Sepsis is the leading cause of AKI, and sepsis-related AKI is one of the main causes of high mortality. Moreover, preterm neonates, as well as patients with post-neonatal asphyxia or after cardiac surgery, are at a high risk for AKI. Critical patients are frequently exposed to nephrotoxic medications, representing a potentially preventable cause of AKI. This review highlights the definition of neonatal AKI, its diagnosis and new biomarkers available in clinical practice and in the near future. We analyze the risk factors involving patients with AKI, their outcomes and the risk for the transition from acute damage to chronic kidney disease.

Prostate cancer reshapes the secreted and extracellular vesicle urinary proteomes

Urine is a complex biofluid that reflects both overall physiologic state and the state of the genitourinary tissues through which it passes. It contains both secreted proteins and proteins encapsulated in tissue-derived extracellular vesicles (EVs). To understand the population variability and clinical utility of urine, we quantified the secreted and EV proteomes from 190 men, including a subset with prostate cancer. We demonstrate that a simple protocol enriches prostatic proteins in urine. Secreted and EV proteins arise from different subcellular compartments. Urinary EVs are faithful surrogates of tissue proteomes, but secreted proteins in urine or cell line EVs are not. The urinary proteome is longitudinally stable over several years. It can accurately and non-invasively distinguish malignant from benign prostatic lesions and can risk-stratify prostate tumors. This resource quantifies the complexity of the urinary proteome and reveals the synergistic value of secreted and EV proteomes for translational and biomarker studies.