Neutrophil gelatinase-associated lipocalin as a diagnostic marker of acute kidney injury in pre-eclampsia

Acute kidney injury in critically ill obstetric patients: Incidence and role of neutrophil gelatinase-associated lipocalcin - A prospective observational cohort study

Background and Aims

Data focussing on acute kidney injury (AKI) in obstetric patients admitted to the intensive care unit (ICU) are scarce and even more so regarding the role of neutrophil gelatinase-associated lipocalcin (NGAL) in detecting AKI or predicting outcomes in these patients. Hence, we aim to evaluate the incidence of AKI in obstetric ICU patients and validate the role of urinary and serum NGAL in predicting the onset of AKI and mortality.

Methods

This prospective observational cohort included 45 obstetric patients admitted in ICU, excluding those with prior renal dysfunction. Serum creatinine and urine output were monitored for the occurrence of AKI during the ICU stay. The outcome of the patient (survival or death) in the ICU and hospital was recorded, and serum and urinary NGAL were determined at the time of ICU admission.

Results

AKI occurred in 32 [71.1%; 95% confidence interval (CI): 55.4%, 86.8%] patients during their ICU stay. Serum NGAL showed an area under receiver operating characteristic curve (AUROCC) of 0.630 (95% CI: 0.417, 0.842) (P = 0.231) for AKI and 0.486 (95% CI: 0.295, 0.676) (P = 0.883) for ICU mortality. Urinary NGAL showed AUROC = 0.472 (95% CI: 0.285, 0.660) (P = 0.772) to predict AKI and 0.430 (95% CI: 0.268, 0.652) (P = 0.684) for ICU mortality.

Conclusions

AKI is common amongst critically ill obstetric ICU patients. However, serum and urinary NGAL cannot be advocated to discriminate between patients with or without AKI or between survivors and non-survivors in critically ill obstetric patients.

Neutrophil Gelatinase-Associated Lipocalin and Hypertensive Disorders of Pregnancy: A Cohort Study in Twin Pregnancies

Hypertensive disorders complicate more than 10% of twin pregnancies. Several studies showed increased neutrophil gelatinase-associated lipocalin (NGAL) values in women with singleton pregnancies and preeclampsia. This study aimed to assess NGAL values in twin pregnancies complicated by hypertensive disorders. We conducted a study of 242 consecutive twin pregnancies at the Medical University of Vienna. Serum NGAL was evaluated twice during pregnancy and once in the postpartum period. Furthermore, serum NGAL values were compared between women who developed hypertensive disorders and those who had normal blood pressure. In all twin pregnancies, mean NGAL values increased significantly from the first to the second visit (p = 0.004) and, further, after delivery (p < 0.001). NGAL was significantly higher in pregnancies that developed pregnancy hypertension or preeclampsia when compared to the control group at the first visit (109.2 ± 48.9 ng/mL vs. 91.9 ± 29.4 ng/mL, p = 0.04, respectively). The predictive power of first visit NGAL values for development of pregnancy hypertension or preeclampsia was evaluated. When using a cut-off value of 115 ng/mL, we obtained a sensitivity of 45% with a specificity of 77%. We conclude that women with twin pregnancies who develop hypertensive disorders of pregnancy showed increased NGAL values at 11−16 weeks.

Malondialdehyde and Neutrophil Gelatinase-Associated Lipocalin as Markers of Oxidative Stress in Small for Gestational Age Newborns from Hypertensive and Preeclamptic Pregnancies

Introduction. It is speculated that preeclampsia and hypertension during pregnancy are associated with an imbalance of the placental antioxidant defence, which results in the overproduction of reactive oxygen species and fetal growth restriction. Many research implied that oxidant stress in utero may be an important determinant of mortality and morbidity in neonates. Moreover, the authors demonstrated the reduced number of nephrons and a higher prevalence of renal injury in neonates with growth restriction, including small for gestational age (SGA) neonates. Alas, it remains unclear whether basal antioxidant status is altered in the kidneys of SGA newborns. Materials and Methods. In this study, we assessed neutrophil gelatinase-associated lipocalin (NGAL) and malondialdehyde (MDA) levels in samples collected from umbilical blood and 12 hours after delivery in neonates born by mothers suffering from preeclampsia or hypertension during pregnancy and those from physiological pregnancies. Additionally, the authors evaluated levels of the aforementioned biomarkers regarding the occurrence of growth restriction in newborns. For this study, we enrolled 27 newborns, which fulfilled inclusion criteria for SGA diagnosis (SGA group), while 21 were appropriate for gestational age neonates, as the AGA group. Results. In the presented study, we have found significant differences in umbilical cord MDA and NGAL concentration between the SGA and AGA groups. Such dependencies were not found in blood samples from neonates collected in the first 12 hours of life for MDA and NGAL concentrations. Additionally, we have observed differences in umbilical MDA and NGAL levels between newborns of preeclamptic or hypertensive mothers compared to healthy ones. A significant correlation between the occurrence of hypertension during pregnancy and umbilical MDA and NGAL concentrations was also found. Conclusions. Small for gestational age newborns or those born by preeclamptic and hypertensive mothers had significantly higher MDA and NGAL levels as compared to healthy ones. Further investigation is needed to understand the pathophysiologic influence of hypertension in pregnancy and oxidative stress injury in newborns with growth restriction.

Acute Kidney Injury in Severe Preeclamptic Patients Admitted to Intensive Care Unit: Epidemiology and Role of Serum Neutrophil Gelatinase-associated Lipocalcin

Background

Patients with preeclampsia admitted to the intensive care unit (ICU) may have risk factors for acute kidney injury (AKI). Although the use of neutrophil gelatinase-associated lipocalcin (NGAL) to predict AKI is previously validated, we could locate only scanty data regarding the epidemiology of AKI and role of NGAL in preeclamptic patients admitted to ICU.

Methods

Patients with preeclampsia admitted to our ICU were included. The incidence and severity of AKI during the entire ICU stay were assessed using kidney disease improving global outcomes criteria, while the a priori risk factors and serum NGAL were also evaluated.

Results

A total of 52 preeclamptic patients admitted to ICU were included, among whom the majority had eclampsia (75%). AKI developed in 25 (48.1%) patients with stages 1, 2, and 3 in 56, 36, and 8%, respectively. The incidence of sepsis (16 vs 0%), shock (40 vs 7.4%), and anemia (84 vs 59.3%) was significantly greater in patients with AKI (p < 0.05). ICU mortality (28 vs 3.7%), duration of ICU, and hospital stay were significantly higher in patients who developed AKI (p < 0.05). There was no association of serum NGAL [274 (240–335) ng/mL] with AKI or the mortality (p = 0.725, 0.861); there was, however, a significant discriminatory value for eclampsia [p = 0.019; area under curve = 0.736 (95% confidence interval: 0.569–0.904)].

Conclusions

Although AKI is common among patients with preeclampsia admitted to ICU, serum NGAL does not predict its occurrence.

How to cite this article

Tyagi A, Yadav P, Salhotra R, Das S, Singh PK, Garg D. Acute Kidney Injury in Severe Preeclamptic Patients Admitted to Intensive Care Unit: Epidemiology and Role of Serum Neutrophil Gelatinase-associated Lipocalcin. Indian J Crit Care Med 2021;25(9):1013–1019.

NGAL for Preeclampsia: How Sure are We?

How to cite this article: Gupta S, Tomar DS. NGAL for Preeclampsia: How Sure are We? Indian J Crit Care Med 2021;25(9):972-973.

Some more about dogs: Proteomics of neglected biological fluids

We report in this manuscript what is known about the protein makeup of a selection of biological fluids in the domestic dog. The samples we review - amniotic and allantoic fluid, seminal fluid, saliva, bile, synovial fluid, tears - are still very poorly characterized in this species. For some of them we can present results from our own, mainly unpublished experiments. SIGNIFICANCE: The dog is one of the most widespread companion animals, and also of medical relevance as model species for some human diseases. Still, investigation of body fluids other than serum and urine is not so commonly undertaken, although - like in humans - also these sample types may have potential for diagnostic purposes. We compile published data about proteomes of fetal fluids, seminal plasma, saliva, bile, synovial fluid and tears, enriched by some yet unpublished data of our own (proteins of amniotic and allantoic fluid, tears). Closing gaps in our knowledge on dog proteins will further our understanding of (patho)physiological processes.

Predictive value of plasma neutrophil gelatinase-associated lipocalin in acute charcoal-burning carbon monoxide poisoning

This study aimed to assess the feasibility of using the plasma neutrophil gelatinase-associated lipocalin (NGAL) level at the time of presentation in the emergency department (ED) to predict acute kidney injury (AKI) and the long-term neurological outcomes of acute charcoal-burning carbon monoxide (CO) poisoning. This retrospective study included 260 patients who suffered acute charcoal-burning CO poisoning. The median plasma NGAL concentration at the time of presentation in the ED after acute charcoal-burning CO poisoning was 78 (54–115) ng/ml. The NGAL level was an independent predictor of AKI development and could be used to stratify the severity of AKI. However, the area under the receiver operating characteristic curve (AUC) of the predictive model for AKI that included both the plasma NGAL level and clinical parameters was comparable to that of the predictive model including only the clinical parameters. The plasma NGAL level at the time of presentation in the ED was an independent factor predicting long-term neurological outcomes in patients who did not develop AKI. In these patients, the plasma NGAL level significantly improved the predictive accuracy of the model when used in combination with clinical parameters. In contrast, the plasma NGAL level was not associated with long-term neurological outcomes in patients who developed AKI. Measurement of the plasma NGAL level at the time ED presentation might improve the prediction of long-term neurological outcomes in patients who do not develop AKI after acute charcoal-burning CO poisoning. However, it might not offer additional benefit for AKI prediction compared to previously used markers.

Expression profiling of lipocalin-2 and 24p3 receptor in murine gonads at different developmental stages

Numerous clinical studies have reported the association between high circulating levels of lipocalin-2 (LCN2) and metabolic diseases. However, only few studies have addressed sexually dimorphic, either in its circulating concentration or in its expression in other organs. To the best of our knowledge, LCN2 and the 24p3 receptor (24p3R), have not been identified in gonads; therefore, the present study analyzed their mRNA expression profile and cellular localization in gonads collected from fetal rats at 21 days post coitum, as well as from neonatal rats at 0, 2, 4, 6, 12, 20 and 30 postnatal days. Semiquantitative polymerase chain reaction and immunohistochemical assays revealed that the LCN2 mRNA during perinatal and pre-pubertal stages presented a sex-specific expression pattern, being higher in ovaries than in testes collected at these stages. Furthermore, the mRNA levels of the long and short isoforms of the 24p3R (507 and 350 bp, respectively), were lower in female gonads from postnatal day 0 onwards in comparison with the levels observed in males, but before birth, the short isoform of the 24p3R was higher in ovaries than in testes. In addition, in females, the abundance of mRNA of this isoform was drastically diminished at 24 h after birth. Furthermore, this specific expression profile of LCN2 and 24p3R at perinatal and prepubertal stages coincides with events of cellular proliferation and apoptosis within both gonads. Immunohistochemical assays revealed that in ovaries, LCN2 and 24p3R are present in germinal and somatic cells of follicles, while in testes, this adipokine and its receptor are only located in germinal cells. These findings suggest that in murine gonads, LCN2/24p3R signaling may be involved either in cell proliferation or cell death driven by gonadotropin-independent or -dependent mechanisms.

Role of Intra-abdominal Pressure in Early Acute Kidney Injury: A Prospective Cohort Study in Critically Ill Obstetric Patients

Aims:

This prospective cohort study evaluated intra-abdominal pressure (IAP) and its role in causing acute kidney injury (AKI) in critically ill obstetric patients and utility of urinary neutrophil gelatinase-associated lipocalin (NGAL) to predict AKI.

Methods:

A total of 50 eligible obstetric patients admitted to our Intensive Care Unit were enrolled and daily IAP measured using indwelling Foley catheter. Early AKI was diagnosed as per the KDIGO criteria and urine assessed for NGAL using ELISA.

Results:

AKI was seen in 54% and intra-abdominal hypertension (IAH) in 21% patients. In patients with and without AKI, there was statistically similar IAP on day 1 (P = 0.542) and day 2 (P = 0.907) as well as incidence of IAH (19% vs. 23%) (P = 0.766). Area under receiver operating characteristic curve (AUC) for IAP to predict early AKI was 0.499 (95% confidence interval [CI]: 0.325–0.673) (P = 0.992). Urinary NGAL concentration was significantly greater in patients with early AKI compared to those without (P = 0.006); AUC for urinary NGAL to detect early AKI was 0.734 (95% CI: 0.583–0.884) (P = 0.006) and optimal cutoff was 53.7 ng/ml.

Conclusions:

IAH and AKI are common in critically ill obstetric patients. While IAP does not correlate with early AKI, NGAL is useful to predict AKI.

Biomarkers of acute kidney injury: the pathway from discovery to clinical adoption

Acute kidney injury (AKI) is a common complication of critical illnesses and has a significant impact on outcomes, including mortality and morbidities. Unfortunately, apart from prophylactic measures, no effective treatment for this syndrome is known. Therefore, early recognition of AKI not only can provide better opportunities for preventive interventions, but also opens many gates for research and development of effective therapeutic options. Over the last few years, several new AKI biomarkers have been discovered and validated to improve early detection, differential diagnosis, and differentiation of patients into risk groups for progressive renal failure, need for renal replacement therapy (RRT), or death. These novel AKI biomarkers complement serum creatinine (SCr) and urine output, which are the standard diagnostic tools for AKI detection. In this article, we review the available literature on characteristics of promising AKI biomarkers that are currently the focus of preclinical and clinical investigations. These biomarkers include neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), liver-type fatty acid-binding protein, interleukin 18 (lL-18), insulin-like growth factor-binding protein 7, tissue inhibitor of metalloproteinase 2 (TIMP-2), calprotectin, urine angiotensinogen (AGT), and urine microRNA. We then describe the clinical performance of these biomarkers for diagnosis and prognostication. We also appraise each AKI biomarker's advantages and limitations as a tool for early AKI recognition and prediction of clinical outcomes after AKI. Finally, we review the current and future states of implementation of biomarkers in the clinical practice.