Serum neutrophil gelatinase-associated lipocalin in ballistic injuries: a comparison between blast injuries and gunshot wounds

Dysregulation of iron transport-related biomarkers in blood leukocytes is associated with poor prognosis of early trauma

Objective

The early targeted and effective diagnosis and treatment of severe trauma are crucial for patients' outcomes. Blood leukocytes act as significant effectors during the initial inflammation and activation of innate immunity in trauma. This study aims to identify hub genes related to patients' prognosis in blood leukocytes at the early stages of trauma.

Methods

The expression profiles of Gene Expression Omnibus (GEO) Series (GSE) 36809 and GSE11375 were downloaded from the GEO database. R software, GraphPad Prism 9.3.1 software, STRING database, and Cytoscape software were used to process the data and identify hub genes in blood leukocytes of early trauma.

Results

Gene Ontology (GO) analysis showed that the differentially expressed genes (DEGs) of blood leukocytes at the early stages of trauma (0-4 h, 4-8 h, and 8-12 h) were mainly involved in neutrophil activation and neutrophil degranulation, neutrophil activation involved in immune response, neutrophil mediated immunity, lymphocyte differentiation, and cell killing. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the DEGs were mainly involved in Osteoclast differentiation and Hematopoietic cell lineage. Sixty-six down-regulated DEGs and 148 up-regulated DEGs were identified and 37 hub genes were confirmed by Molecular Complex Detection (MCODE) of Cytoscape. Among the hub genes, Lipocalin 2 (LCN2), Lactotransferrin (LTF), Olfactomedin 4 (OLFM4), Resistin (RETN), and Transcobalamin 1 (TCN1) were related to prognosis and connected with iron transport closely. LCN2 and LTF were involved in iron transport and had a moderate predictive value for the poor prognosis of trauma patients, and the AUC of LCN2 and LTF was 0.7777 and 0.7843, respectively.

Conclusion

As iron transport-related hub genes in blood leukocytes, LCN2 and LTF can be used for prognostic prediction of early trauma.

The role of neutrophil gelatinase-associated lipocalin (NGAL) in the detection of blast lung injury in a military population

PURPOSE

To study the relationship between serum neutrophil gelatinase-associated lipocalin (NGAL) and military blast and gunshot wound (GSW) to establish whether potential exists for NGAL as a biomarker for blast lung injury (BLI).

METHOD

Patients from the intensive care unit (ICU) of the Role 3 Medical Treatment Facility at Camp Bastion, Helmand Province, Afghanistan were studied over a five month period commencing in 2012. Age, mechanism, trauma injury severity score (TRISS) and serum NGAL were recorded on ICU admission (NGAL1). Serum NGAL (NGAL2) and PaO₂/FiO₂ ratio (P/F ratio2) were recorded at 24h.

RESULTS

33 patients were injured by blast and 23 by GSW. NGAL1 inversely correlated with TRISS (p=0.020), pH (p=0.002) and P/F ratio 2 (p=0.009) overall. When data was stratified into blast and GSW, NGAL1 also inversely correlated with P/F ratio 2 in the blast injured group (p=0.008) but not GSW group (p=0.27).

CONCLUSION

Raised NGAL correlated with increased severity of injury (worse survival probability i.e. TRISS and low pH) in both patient groups. There was an inverse correlation between admission NGAL and a marker of blast lung injury (low P/F ratio) at 24h in blast injured group but not GSW group that warrants further investigation.

Urinary Biomarkers are Associated with Severity and Mechanism of Injury

Combat-related blast trauma results in massive tissue injury and tends to involve multiple systems. Further, an acute measure of injury severity based on underlying biological mechanisms may be important for the triage and treatment of these types of patients. We hypothesized that urinary biomarkers (UBs) would reflect severity of injury and that they would be elevated for blast injuries compared with gunshot wounds (GSW) in a cohort of combat casualties. We also postulated that UBs would be higher in patients with burns compared with patients with non-burn trauma in a civilian cohort. Among 80 service members who sustained combat-related injuries, we performed generalized estimating equations to compare differences in log-transformed concentrations of the UBs by both injury severity and injury mechanism. Among 22 civilian patients, we performed Kruskal-Wallis tests to compare differences for the UBs stratified by burn and non-burn trauma. In the military cohort, with the exception of IL-18, all UBs were significantly (P <0.05) higher for patients with a severe combat-related injury (Injury Severity Score ≥25). In addition, all crude UBs concentrations were significantly higher for blast versus GSW patients (P < 0.05). After adjusting for injury severity score and time of UB draw, KIM-1 (2.80 vs. 2.31; P = 0.03) and LFABP (-1.11 vs. -1.92; P = 0.02) were significantly higher for patients with a blast mechanism of injury. There were no significant differences in UBs between burn and non-burn civilian trauma patients. Future studies are needed to understand the physiologic response to trauma and the extent that UBs reflect these underlying processes.

Pulse wave velocity and neutrophil gelatinase-associated lipocalin as predictors of acute kidney injury following aortic valve replacement

BACKGROUND

Accurate prediction, early detection and treatment of acute kidney injury (AKI) are essential for improving post-operative outcomes. This study aimed to examine the role of aortic stiffness and neutrophil gelatinase-associated lipocalin (NGAL) as predictors of AKI or need for early medical renal intervention following aortic valve replacement (AVR).

METHODS

Aortic pulse wave velocity and plasma NGAL were measured pre-operatively in recruited patients undergoing AVR for aortic stenosis (AS). Plasma NGAL was also measured at 3 and 18-24 hours after cardiopulmonary bypass (CPB). AKI was defined using RIFLE criteria. Early medical renal intervention included diuretics or dopamine infusion exclusively for renal causes.

RESULTS

Fifty-three patients aged 71 ± 9 years were included. Sixteen (30%) developed AKI (AKI-Yes) and 24 patients (45%) received early medical intervention (Intervention-Yes). There was no significant difference in the demographic, clinical or operative characteristics between the two groups for either outcome. PWV did not significantly correlate with AKI (r = 0.12, P = 0.13) or early intervention (r = 0.18, P = 0.18). At 3 h post-CPB, plasma NGAL was a much stronger predictor of both AKI and the need for early medical intervention than conventional markers such as creatinine (AKI: AUC 83%, 95% CI 0.70-0.95 vs. AUC 65%, 95% CI 0.47- 0.82; Medical intervention: AUC 84%, 95% CI 0.72-0.96 vs. AUC 56%, 95% CI 0.38-0.73). Post-CPB (3 hr) plasma NGAL was also significantly associated with AKI (r = 0.68, P < 0.001) at levels above 150 ng/ml; and significantly associated with early intervention (r = 0.64, P < 0.001) above 136 ng/ml. Simple linear regression showed no relationship between PWV and NGAL levels.

CONCLUSION

Aortic PWV does not correlate significantly with post-operative AKI or plasma NGAL levels in surgical AS patients. Post-operative NGAL is however an early and powerful predictive biomarker of both post-operative AKI and the need for early medical renal intervention and should consequently be considered in prediction models for AKI after cardiac surgery.

Serum and plasma neutrophil gelatinase associated lipocalin (NGAL) levels are not equivalent in patients admitted to intensive care

BACKGROUND

Neutrophil gelatinase associated lipocalin (NGAL) is proposed as a biomarker of acute kidney injury (AKI). NGAL has been studied in a range of body fluids including serum and EDTA plasma. The aim of the present study was to establish relationship between serum NGAL concentrations and EDTA plasma NGAL concentrations in patients admitted to intensive care units (ICUs) and whether these determinations are directly comparable in this setting.

METHODS

NGAL was measured in 40 paired samples of serum and EDTA plasma from 25 patients admitted to intensive care with a commercial particle-enhanced turbidimetric immunoassay (The NGAL Test™, BioPorto Diagnostics A/S, Gentofte, Denmark) on a Roche Hitachi 917 (Roche-Hitachi, Inc., Tokyo, Japan) analyzer.

RESULTS

Serum NGAL concentrations ranged from 26.8 to 1,808 ng/ml (median 281 ng/ml, interquartile range (IQR) 453 ng/ml). EDTA plasma NGAL concentrations ranged from 25.7 to 1,752 ng/ml (median 225 ng/ml, IQR 352 ng/ml). The difference in NGAL concentrations in paired serum and EDTA plasma samples (serum- plasma) ranged from -13.8 to 321 ng/ml (median 79 ng/ml, IQR 116 ng/ml; difference from zero, P < 0.0001, Wilcoxon's signed rank test). Although serum and EDTA plasma values were correlated (Spearman's r = 0.95, P < 0.0001), Deming regression analysis showed a slope of 1.1 that was not significantly different from unity (95% confidence interval (CI) 1.0-1.1) and a highly significant intercept of 67.9 ng/ml with a wide confidence interval (95% CI 29.8-106).

CONCLUSION

NGAL concentration values measured in serum and EDTA plasma cannot be directly compared and should not be used as equivalents in studies of patients admitted to intensive care.

Renal function after trauma

OBJECTIVE

The lack of need for immediate renal replacement treatment for military trauma victims suggests that the current policy of restricting operational deployment of those Service personnel with active inflammatory renal disease and significantly impaired renal function, combined with good prehospital care for all trauma casualties, is probably correct. No published estimates of renal function in civilian or military trauma victims in the earliest period following injury have been retrieved. The purpose of the present retrospective study was to assess the renal function of military trauma victims on arrival in the Emergency Department of the field hospital.

METHODS

The case records of 287 military trauma casualties with severe injury (New Injury Severity Score, NISS≥16) were retrospectively reviewed to assess renal function by calculating estimated glomerular filtration rate (eGFR) using the serum creatine concentration obtained immediately on arrival in the Emergency Department of the field hospitals in Iraq and Afghanistan, 2005-2009. Correlations were attempted between eGFR and other clinical and laboratory variables.

RESULTS

Hospital case notes recording management following repatriation were retrieved in 221/287 (77%) cases. None had required immediate renal support in the field. Serum creatine concentration on arrival in the field hospital with demographic data permitting calculation of eGFR was recorded in 158 cases. Median eGFR=76 ml/min/1.73 m(2) (range=43-144). Statistically significant correlations were found among eGFR and pulse rate (r=-0.3, p=0.0002), body temperature (r=0.24, p=0.01) and mean arterial pressure (r=0.2, p=0.02). No statistically significant correlation was found among eGFR and NISS, white cell count, or respiration rate. A stepwise multivariate regression analysis of 106 cases suggested that the best combination of clinical observations to predict renal function were pulse rate and body temperature but the prediction was overoptimistic at lower eGFR values. eGFR was statistically significantly different in those satisfying criteria for systemic inflammatory response syndrome (SIRS; eGFR with SIRS=76 and eGFR without SIRS=86 ml/min/1.73 m(2)).

CONCLUSIONS

Prehospital resuscitative measures are effective in maintaining renal function at an adequate level until arrival in the field hospital. The combination of tachycardia and hypothermia predicts lower renal function, variables already employed in the assessment of injury severity. The observations in the present study support restriction of recruitment and operational deployment where renal problems exist.