NEUTROPHIL GELATINASE-ASSOCIATED LIPOCALIN AS AN EARLY BIOMARKER OF ACUTE KIDNEY INJURY IN NEWBORNS

A comparative proteomic analysis for non-invasive early prediction of hypoxic-ischemic injury in asphyxiated neonates

AIM

Hypoxic Ischemic Encephalopathy (HIE) is one of the principal causes of neonatal mortality and long-term morbidity worldwide. The neonatal signs of mild cerebral injury are subtle, making an early precise diagnosis difficult. Delayed detection, poor prognosis, and lack of specific biomarkers for the disease are increasing mortality rates. In this study, we intended to identify specific biomarkers using comparative proteomic analysis to predict the severity of perinatal asphyxia so that its outcome can also be prevented.

EXPERIMENTAL DESIGN

A case-control study was conducted on 38 neonates, and urine samples were collected within 24 and 72 h of life. A tandem mass spectrometry-based quantitative proteomics approach, followed by validation via sandwich ELISA, was performed.

RESULTS

The LC-MS/MS-based proteomics analysis resulted in the identification of 1201 proteins in urine, with 229, 244, and 426 being differentially expressed in HIE-1, HIE-2, and HIE-3, respectively. Axon guidance, Diseases of programmed cell death, and Detoxification of reactive oxygen species pathways were significantly enriched in mild HIE versus severe HIE. Among the differentially expressed proteins in various stages of HIE, we chose to validate four proteins - APP, AGT, FABP1, and FN1 - via sandwich ELISA. Individual and cumulative ROC curves were plotted. AGT and FABP1 together showed high sensitivity, specificity, and accuracy as potential biomarkers for early diagnosis of HIE.

CONCLUSION

Establishing putative urinary biomarkers will facilitate clinicians to more accurately screen neonates for brain injury and monitor the disease progression. Prompt treatment of neonates may reduce mortality and neurodevelopmental impairment.

Iron homeostasis and post-hemorrhagic hydrocephalus: a review

Iron physiology is regulated by a complex interplay of extracellular transport systems, coordinated transcriptional responses, and iron efflux mechanisms. Dysregulation of iron metabolism can result in defects in myelination, neurotransmitter synthesis, and neuronal maturation. In neonates, germinal matrix-intraventricular hemorrhage (GMH-IVH) causes iron overload as a result of blood breakdown in the ventricles and brain parenchyma which can lead to post-hemorrhagic hydrocephalus (PHH). However, the precise mechanisms by which GMH-IVH results in PHH remain elusive. Understanding the molecular determinants of iron homeostasis in the developing brain may lead to improved therapies. This manuscript reviews the various roles iron has in brain development, characterizes our understanding of iron transport in the developing brain, and describes potential mechanisms by which iron overload may cause PHH and brain injury. We also review novel preclinical treatments for IVH that specifically target iron. Understanding iron handling within the brain and central nervous system may provide a basis for preventative, targeted treatments for iron-mediated pathogenesis of GMH-IVH and PHH.

COMPARISON OF LAPAROSCOPIC AND OPEN PYELOPLASTY IMPACT ON COMFORT AND SUCCESS: A RETROSPECTIVE, SINGLE CENTER STUDY

Ureteropelvic junction obstruction causes hydronephrosis and may lead to renal parenchymal damage unless timely diagnosed and treated. Although open pyeloplasty is still the gold standard, it needs to be compared with new techniques. In this study, we compared laparoscopic and open pyeloplasty. Data on 113 patients who had undergone surgery between 2008 and 2014 were evaluated retrospectively. Thirty-nine patients had undergone laparoscopic pyeloplasty, and 74 had undergone open pyeloplasty. Ultrasonography was performed at 3 months and scintigraphy at 6 months postoperatively. Parameters such as the length of surgery, need for analgesics, length of hospital stay, complications, and success rates were compared. When compared to open pyeloplasty (mean 9.8 dexketoprofen 50 mg IV dose), the need for an analgesic was significantly lower in the laparoscopic pyeloplasty (mean 4.5, paracetamol 15 mg/kg IV dose) group (p<0.05). The length of hospital stay was also shorter in the laparoscopic pyeloplasty group (mean 4.0 days) than in the open pyeloplasty group (mean 7.3 days) (p<0.05). This study demonstrated that laparoscopic pyeloplasty could be safely used in the treatment of ureteropelvic junction obstruction with a lower need for analgesics and a shorter length of hospital stay than with open pyeloplasty.

Neutrophil Gelatinase-Associated Lipocalin as Potential Predictive Biomarker of Melanoma and Non-Melanoma Skin Cancers in Psoriatic Patients: A Pilot Study

Background: Studies have demonstrated a higher risk of nonmelanoma skin cancers (NMSC) and a modestly increased melanoma risk in patients with psoriasis. To date, no biomarkers predictive of evolution have been identified yet. Methods: The aim of this prospective case-control study was to investigate the potential role of neutrophil gelatinase-associated lipocalin (NGAL) as a predictive biomarker of skin cancers in psoriatic patients. Patients with a diagnosis of psoriasis were enrolled, as well as healthy subjects and patients with skin cancers as controls. Plasma protein expression of NGAL, metalloproteinases (MMP)-2, and MMP-9 was performed by an enzyme-linked immunosorbent assay (ELISA). In all the patients who developed skin cancer at follow-up, NGAL, MMP-2, and MMP-9 serum levels were dosed again. Results: Plasma NGAL levels were significantly higher in psoriatic patients with NMSC than without (182.3 ± 36.6 ng/mL vs. 139.9 ± 39.3 ng/mL) (p < 0.001). Plasma NGAL levels were significantly higher (p < 0.00001) in patients with psoriasis and NMSC than in patients with skin tumors without psoriasis (182.3 vs. 122.9). Patients with psoriasis who developed NMSC at follow-up showed increased plasma MMP-9 levels. Conclusion: NGAL seems to play a role in the pathogenesis of NMSC but not melanoma in patients with psoriasis.

uNGAL Predictive Value for Serum Creatinine Decrease in Critically Ill Children

Acute kidney injury (AKI) occurs frequently in critically ill children, having an incidence of up to 26.9% and is associated with high morbidity and mortality in pediatric intensive care units (PICU). Currently, the decrease in the glomerular filtration rate is calculated using the serum creatinine levels. Nevertheless, there may be a 48 h delay between the renal injury and measurable increase in creatinine. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has been validated in relation to cardiopulmonary bypass in children, being able to detect AKI before the functional change proven by the rise in serum creatinine. Our aim was to study the utility of using uNGAL in the management of critical pediatric patients admitted to our hospital in a six month period, more specifically, its capacity to predict AKI development, alone and in the association with the renal angina index (RAI). Twenty-eight critically ill children aged from 1 day to 15 years have been included. We found that an increase in uNGAL in day 1 of admission in the PICU was significantly correlated with a decrease in creatinine clearance but not anymore in day 3. However, in our sample uNGAL did not show a significant predictability for AKI development nor the supplementary incorporation of RAI into the prediction model. Therefore, apart from cardiac surgery, the efficacy and utility or uNGAL in the management of critically ill children is still questionable. For the best prediction, we will need to incorporate not only the RAI or other PICU scores, but other biomarkers such as KIM-1, urinary cystatin, and IL 18 in larger samples.

Sevoflurane preconditioning prevents acute renal injury caused by ischemia‑reperfusion in mice via activation of the Nrf2 signaling pathway

Oxidative stress, caused by renal ischemia reperfusion (IR)/hypoperfusion, is one of the main causes of acute kidney injury (AKI). Previous studies have demonstrated that sevoflurane (SEV) protects organs from the damage caused by oxidative stress. In the present study, mice were randomly assigned to a sham operation group (Sham), IR-vehicle group (IR+ vehicle), IR + SEV low-dose preconditioning group and an IR + SEV high-dose preconditioning group. The effect of SEV on nuclear factor E2-related factor 2 (Nrf2), a key regulatory protein of the endogenous antioxidant defense system and, consequently oxidative stress, inflammation and apoptosis-related factors, were all quantified using commercial kits or by western blotting. SEV preconditioning was demonstrated to ameliorate kidney injury as a result of decreased blood urine nitrogen and serum creatinine levels, activated Nrf2 expression in the kidney and decreased oxidative stress and inflammatory index levels an AKI mouse model. SEV preconditioning also protected injured kidney via the downregulation of caspase-3 protein expression levels. In addition, using the Nrf2 inhibitor, Brusatol, significantly abolished the SEV preconditioning renal protective effect. Using an in vitro HK-2 cell model of hypoxia/reoxygenation, it was also demonstrated that Nrf2 pathway activation was necessary for SEV to exert its beneficial effect for tubular cell injury caused by hypoxia/reoxygenation. These results indicated that SEV may protect against renal injury caused by IR via Nrf2 upregulation.

Isolation and Characterization of Urinary Extracellular Vesicles for MicroRNA Biomarker Signature Development with Reference to MISEV Compliance

Urine bears high potential for serving as biomarker repository for renal and urinary tract associated disorders. Besides various metabolites and salts, urine carries extracellular vesicles (EVs)-a heterogeneous group of cell-derived mediators comprising proteins, lipids, and nucleic acids such as microRNAs (miRNAs). Particularly, EV-derived miRNA biomarkers have already been identified for numerous disorders such as sepsis, various blood and solid cancer entities, respiratory and renal diseases. However, study results are often incomparable due to poorly reported EV separation and miRNA isolation protocols and emphasize the need for standardization and reproducibility. To ensure valid EV-derived miRNA biomarker findings from urine, a step-by-step protocol compliant with the "Minimal Information for Studies of Extracellular Vesicles" (MISEV) is outlined in the following paragraphs. Actually, an immunoaffinity-based EV separation method followed by EV characterization, quantification, and normalization, as well as consecutive miRNA isolation and miRNA profiling by small RNA sequencing, are described.