TNFR1, TNFR2, neutrophil gelatinase-associated lipocalin and heparin binding protein in identifying sepsis and predicting outcome in an intensive care cohort

Plasma soluble tumor necrosis factor receptor I as a biomarker of lupus nephritis and disease activity in systemic lupus erythematosus patients

OBJECTIVES

The goal of our study was to evaluate the potential role of sTNF-RI as a biomarker of renal involvement in SLE patients and active SLE.

METHODS

The study sample consisted of two cohorts. The discovery cohort included 16 SLE patients without renal involvement (non-LN), 60 lupus nephritis (LN) patients and 21 healthy controls (HCs) and the replication cohort included 18 SLE non-LN patients, 116 LN patients and 36 HCs.

RESULTS

The sTNF-RI levels differed significantly in the discovery cohort. The plasma sTNF-RI levels were higher in LN patients than in non-LN patients (p = .009) and HCs (p = 4 × 10^-6). Plasma sTNF-RI levels were significantly higher in non-LN patients than in HCs (p = .03). The finding was confirmed in independent replication cohort (LNs vs. non-LN, p = 4.053 × 10^-7; LNs vs. HCs, p = 2.395 × 10^-18; non-LN vs. HCs, p = 2.51 × 10^-4). The plasma sTNF-RI levels were associated with disease activity, renal function in SLE patients and urine protein in LN patients. The multivariate analysis revealed that high sTNF-RI was an independent risk factor for renal involvement. The multivariate logistic regression results suggested that high TNF-RI, high systolic blood pressure, high serum creatinine, low C4 and positive anti-dsDNA were independent risks of active SLE patients. A nomogram was constructed based on the results of multivariate logistic regression analysis and it was practical in predicting the risk of the active SLE patients. Immunohistochemistry suggested that the expression of TNF-RI in the kidney was increased.

CONCLUSIONS

Plasma sTNF-RI might be a good biomarker of renal involvement and disease activity in SLE patients.

Diagnosis of septic shock by serum measurement of human neutrophil lipocalin by a rapid homogeneous assay

BACKGROUND

Human neutrophil lipocalin (HNL) is a marker of neutrophil activation and has a high efficacy in diagnosing bacterial infections. In this study, we applied the AlphaLISA technique to measure the serum level of HNL, evaluate HNL's efficacy in diagnosing septic shock, and identify any association between HNL level and septic patients' prognosis.

METHODS

We collected 146 serum samples from the Fifth Medical Center of Chinese PLA General Hospital. HNL was measured by AlphaLISA and results were compared with commercial ELISA kits. We studied 78 patients admitted to the ICU with sepsis and data on their clinical and physiological characteristics were recorded. Blood levels of HNL, procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP), and lactate were measured. A receiver operating characteristic (ROC) curve was used to evaluate the performance of each marker.

RESULTS

The AlphaLISA assay for serum HNL had a detection range from 1.5 ng/mL to 1000 ng/mL, with a detection limit of 1 ng/mL and a detection time of approximately 25 min. The AlphaLISA assay's results were in high agreement with ELISA results (R2 = 0.9413). HNL levels were analyzed in sepsis patients, and HNL was significantly higher in sepsis patients with shock compared to sepsis patients without shock (median 356.47 ng/mL vs 158.93 ng/mL, P < 0.0001) and in the 28-day non-survivor group compared to the 28-day survivor group (median 331.83 ng/mL vs 175.17 ng/mL, P < 0.0001). ROC curve analysis was performed for the biomarkers. In differentiating the diagnosis of septic shock from sepsis patients, HNL was the most effective marker (AUC = 0.857), followed by PCT (AUC = 0.754) and hs-CRP (AUC = 0.627). In predicting the prognosis of septic patients, lactate had the best effect (AUC = 0.805), followed by HNL (AUC = 0.784), PCT (AUC = 0.721), and hs-CRP (AUC = 0.583).

CONCLUSIONS

As an assessment tool, we found that our AlphaLISA had good consistency with an ELISA and had several other advantages, including requiring a shorter processing time and detecting a wider range of serum HNL concentrations. Monitoring serum HNL levels of patients admitted to the ICU might be useful in distinguishing sepsis patients who have septic shock from other sepsis patients, indicating its value in the prediction of sepsis patient prognosis.

Acute Kidney Injury-Induced Circulating TNFR1/2 Elevations Correlate with Persistent Kidney Injury and Progression to Fibrosis

Elevated levels of circulating tumor necrosis factor receptors 1 and 2 (cTNFR1/2) predict chronic kidney disease (CKD) progression; however, the mechanisms of their release remain unknown. Whether acute kidney injury (AKI) drives cTNFR1/2 elevations and whether they predict disease outcomes after AKI remain unknown. In this study, we used AKI patient serum and urine samples, mouse models of kidney injury (ischemic, obstructive, and toxic), and progression to fibrosis, nephrectomy, and related single-cell RNA-sequencing datasets to experimentally test the role of kidney injury on cTNFR1/2 levels. We show that TNFR1/2 serum and urine levels are highly elevated in all of the mouse models of kidney injury tested, beginning within one hour post injury, and correlate with its severity. Consistent with this, serum and urine TNFR1/2 levels are increased in AKI patients and correlate with the severity of kidney failure. Kidney tissue expression of TNFR1/2 after AKI is only slightly increased and bilateral nephrectomies lead to strong cTNFR1/2 elevations, suggesting the release of these receptors by extrarenal sources. The injection of the uremic toxin indoxyl sulfate in healthy mice induces moderate cTNFR1/2 elevations. Moreover, TNF neutralization does not affect early cTNFR1/2 elevations after AKI. These data suggest that cTNFR1/2 levels in AKI do not reflect injury-induced TNF activity, but rather a rapid response to loss of kidney function and uremia. In contrast to traditional disease biomarkers, such as serum creatinine or BUN, cTNFR1/2 levels remain elevated for weeks after severe kidney injury. At these later timepoints, cTNFR1/2 levels positively correlate with remaining kidney injury. During the AKI-to-CKD transition, elevations of TNFR1/2 kidney expression and of cTNFR2 levels correlate with kidney fibrosis levels. In conclusion, our data demonstrate that kidney injury drives acute increases in cTNFR1/2 serum levels, which negatively correlate with kidney function. Sustained TNFR1/2 elevations after kidney injury during AKI-to-CKD transition reflect persistent tissue injury and progression to kidney fibrosis.

Definitions, phenotypes, and subphenotypes in acute kidney injury-Moving towards precision medicine

The current definition of acute kidney injury (AKI) is generic and, based only on markers of function, is unsuitable for guiding individualized treatment. AKI is a complex syndrome with multiple presentations and causes. Targeted AKI management will only be possible if different phenotypes and subphenotypes of AKI are recognised, based on causation and related pathophysiology. Molecular signatures to identify subphenotypes are being recognised, as specific biomarkers reveal activated pathways. Assessment of individual clinical risk needs wider dissemination to allow identification of patients at high risk of AKI. New and more timely markers for glomerular filtration rate (GFR) are available. However, AKI diagnosis and classification should not be limited to GFR, but include tubular function and damage. Combining damage and stress biomarkers with functional markers enhances risk prediction, and identifies a population enriched for clinical trials targeting AKI. We review novel developments and aim to encourage implementation of these new techniques into clinical practice as a strategy for individualizing AKI treatment akin to a precision medicine-based approach.

Urinary Neutrophil Gelatinase-Associated Lipocalin Predicts Intensive Care Unit Admission Diagnosis: A Prospective Cohort Study

BACKGROUND

Acute kidney injury (AKI) is most commonly caused by tubular injury and is associated with a wide variety of critical illnesses. It is well known that urinary biomarkers can lead to the early identification of AKI. However, the ability of urinary biomarkers to distinguish between different types of critical illness has been less studied.

METHODS

In this prospective cohort study, urinary neutrophil gelatinase-associated lipocalin (uNGAL) was measured in 107 patients consecutively admitted to the ICUs in our tertiary medical center. uNGAL samples were collected within 3-6 hours of admission to an ICU and measured by ELISA. All data were analyzed using R statistical software, and univariate analysis was used to determine the correlations of uNGAL levels with AKI stage, admission diagnoses, and ICU course.

RESULTS

uNGAL level increased by a mean of 24-fold (SD 10-59) in ICU patients with AKI and demonstrated a significant correlation with the different AKI stages. uNGAL predicted the need for RRT, with values increased by more than 15-fold (P<0.05) in patients needing RRT, and remained a useful tool to predict AKI in ICU patients with a urinary tract infection. uNGAL level was correlated with certain ICU admitting diagnoses whereby uNGAL levels were lower in ICU patients with cardiogenic shock compared with other admission diagnoses (β=-1.92, P<0.05).

CONCLUSIONS

uNGAL can be used as an early predictor of AKI and its severity in patients admitted to the ICU, including the need for RRT. uNGAL may also help in distinguishing patients with cardiogenic shock from those with other critical illnesses and identifying those at risk for poor outcomes irrespective of the presence of AKI.

Hepcidin discriminates sepsis from other critical illness at admission to intensive care

Initial differential diagnosis and prognosis for patients admitted to intensive care with suspected sepsis remain arduous. Hepcidin has emerged as a potential biomarker for sepsis. Here we report data on the relevance of levels of hepcidin versus other biomarkers as a diagnostic and prognostic tool for sepsis. 164 adult patients admitted to the intensive care unit (ICU) within 24 h upon arrival to the hospital were included. Blood samples collected daily for seven consecutive days and hepcidin levels, heparin binding protein (HBP) levels and standard biomarkers were determined. Blood cultures were initiated at inclusion. Clinical scores were evaluated daily and mortality after 28- and 180-days was recorded. One hundred of the patients were found to fulfil the criteria for sepsis whereas 64 did not. Hepcidin levels at admission were significantly higher in the septic than in the non-septic patients. In septic patients hepcidin levels declined significantly already at 24 h followed by a steady decline. A significant negative correlation was observed between hepcidin levels and SAPS 3 in patients with sepsis. Hepcidin levels at inclusion were significantly higher among septic patients that survived 180-days and predicted mortality. Our data show that hepcidin levels are indicative of sepsis in patients admitted to the ICU and has a prognostic value for mortality.

Acute Kidney Injury Associates with Long-Term Increases in Plasma TNFR1, TNFR2, and KIM-1: Findings from the CRIC Study

BACKGROUND

Some markers of inflammation-TNF receptors 1 and 2 (TNFR1 and TNFR2)-are independently associated with progressive CKD, as is a marker of proximal tubule injury, kidney injury molecule 1 (KIM-1). However, whether an episode of hospitalized AKI may cause long-term changes in these biomarkers is unknown.

METHODS

Among adult participants in the Chronic Renal Insufficiency Cohort (CRIC) study, we identified 198 episodes of hospitalized AKI (defined as peak/nadir inpatient serum creatinine values ≥1.5). For each AKI hospitalization, we found the best matched non-AKI hospitalization (unique patients), using prehospitalization characteristics, including eGFR and urine protein/creatinine ratio. We measured TNFR1, TNFR2, and KIM-1 in banked plasma samples collected at annual CRIC study visits before and after the hospitalization (a median of 7 months before and 5 months after hospitalization).

RESULTS

In the AKI and non-AKI groups, we found similar prehospitalization median levels of TNFR1 (1373 pg/ml versus 1371 pg/ml, for AKI and non-AKI, respectively), TNFR2 (47,141 pg/ml versus 46,135 pg/ml, respectively), and KIM-1 (857 pg/ml versus 719 pg/ml, respectively). Compared with matched study participants who did not experience AKI, study participants who did experience AKI had greater increases in TNFR1 (23% versus 10%, P<0.01), TNFR2 (10% versus 3%, P<0.01), and KIM-1 (13% versus -2%, P<0.01).

CONCLUSIONS

Among patients with CKD, AKI during hospitalization was associated with increases in plasma TNFR1, TNFR2, and KIM-1 several months after their hospitalization. These results highlight a potential mechanism by which AKI may contribute to more rapid loss of kidney function months to years after the acute insult.

Advances in Immune Monitoring Approaches for Sepsis-Induced Immunosuppression

Sepsis represents a life-threatening organ dysfunction due to an aberrant host response. Of note is that majority of patients have experienced a severe immune depression during and after sepsis, which is significantly correlated with the occurrence of nosocomial infection and higher risk of in-hospital death. Nevertheless, the clinical sign of sepsis-induced immune paralysis remains highly indetectable and ambiguous. Given that, specific yet robust biomarkers for monitoring the immune functional status of septic patients are of prominent significance in clinical practice. In turn, the stratification of a subgroup of septic patients with an immunosuppressive state will greatly contribute to the implementation of personalized adjuvant immunotherapy. In this review, we comprehensively summarize the mechanism of sepsis-associated immunosuppression at the cellular level and highlight the recent advances in immune monitoring approaches targeting the functional status of both innate and adaptive immune responses.

Reference interval for urinary neutrophil gelatinase-associated lipocalin in healthy adults in Jiangsu region in Eastern China: a multicenter study

Aim: We explored the concentrations of urinary neutrophil gelatinase-associated lipocalin (NGAL) in healthy adults in the Jiangsu region in Eastern China and established a reference interval using latex-enhanced immunoturbidimetry to provide important guidelines for the interpretation and application of urinary NGAL in clinical practice. Methods: In total, 1970 eligible subjects from four regions were included in this study. The urinary NGAL levels were measured using an AU5800 automatic biochemical analyzer with its matched reagents. The urinary NGAL reference interval was established using the one-sided percentile method (95th percentile). Results: The urinary NGAL data were non-normally distributed. The urinary NGAL levels were not significantly different by sex or age. Therefore, the urinary NGAL reference interval in healthy adults in the Jiangsu region in Eastern China was <87.5 ng/ml (95th percentile of the upper limit). Conclusion: Urinary NGAL reference interval will play an important role in promoting the clinical value of urinary NGAL.

Soluble TNF receptors predict acute kidney injury and mortality in critically ill COVID-19 patients: A prospective observational study

Background

Although pneumonia is the hallmark of coronavirus disease 2019 (COVID-19), multiple organ failure may develop in severe disease. TNFα receptors in their soluble form (sTNFR) are involved in the immune cascade in other systemic inflammatory processes such as septic shock, and could mediate the inflammatory activation of distant organs. The aim of this study is to analyse plasma levels of sTNFR 1 and 2 in association with organ failure and outcome in critically ill patients with COVID-19.

Methods

After informed consent, we included 122 adult patients with PCR-confirmed COVID-19 at ICU admission. Demographic data, illness severity scores, organ failure and survival at 30 days were collected. Plasma sTNFR 1 and 2 levels were quantified during the first days after ICU admission. Twenty-five healthy blood donors were used as control group.

Results

Levels of sTNFR were higher in severe COVID-19 patients compared to controls (p < 0.001). Plasma levels of sTNFR were associated to illness severity scores (SAPS 3 and SOFA), inflammation biomarkers such as IL-6, ferritin and PCT as well as development of AKI during ICU stay. sTNFR 1 higher than 2.29 ng/mL and? sTNFR 2 higher than 11.7 ng/mL were identified as optimal cut-offs to discriminate survivors and non-survivors 30 days after ICU admission and had an area under the curve in receiver operating characteristic curve of 0.75 and 0.67 respectively.

Conclusion

Plasma levels of sTNFR 1 and 2 were higher in COVID-19 patients compared to controls and were strongly associated with other inflammatory biomarkers, severity of illness and acute kidney injury development during ICU stay. In addition, sTNFR 1 was an independent predictor of 30-day mortality after adjustment for age and respiratory failure.