Reduction in urinary excretion of neutrophil gelatinase-associated lipocalin by angiotensin receptor blockers in hypertensive patients

Protein Biomarkers in Chronic Kidney Disease in Children-What Do We Know So Far?

Chronic kidney disease (CKD) in children is a major concern of medical care and public health as it is related to high morbidity and mortality due to progression to end-stage kidney disease (ESKD). It is essential to identify patients with a risk of developing CKD to implement therapeutic interventions. Unfortunately, conventional markers of CKD, such as serum creatinine, glomerular filtration rate (GFR) and proteinuria, have many limitations in serving as an early and specific diagnostic tool for this condition. Despite the above, they are still the most frequently utilized as we do not have better. Studies from the last decade identified multiple CKD blood and urine protein biomarkers but mostly assessed the adult population. This article outlines some recent achievements and new perspectives in finding a set of protein biomarkers that might improve our ability to prognose CKD progression in children, monitor the response to treatment, or even become a potential therapeutic target.

Candesartan could ameliorate the COVID-19 cytokine storm

BACKGROUND

Angiotensin receptor blockers (ARBs) reducing inflammation and protecting lung and brain function, could be of therapeutic efficacy in COVID-19 patients.

METHODS

Using GSEA, we compared our previous transcriptome analysis of neurons injured by glutamate and treated with the ARB Candesartan (GSE67036) with transcriptional signatures from SARS-CoV-2 infected primary human bronchial epithelial cells (NHBE) and lung postmortem (GSE147507), PBMC and BALF samples (CRA002390) from COVID-19 patients.

RESULTS

Hundreds of genes upregulated in SARS-CoV-2/COVID-19 transcriptomes were similarly upregulated by glutamate and normalized by Candesartan. Gene Ontology analysis revealed expression profiles with greatest significance and enrichment, including proinflammatory cytokine and chemokine activity, the NF-kappa B complex, alterations in innate and adaptive immunity, with many genes participating in the COVID-19 cytokine storm.

CONCLUSIONS

There are similar injury mechanisms in SARS-CoV-2 infection and neuronal injury, equally reduced by ARB treatment. This supports the hypothesis of a therapeutic role for ARBs, ameliorating the COVID-19 cytokine storm.

Emerging biomarkers of chronic kidney disease in children

Chronic kidney disease (CKD) has become a significant public health concern, as it is associated with substantial morbidity. Prior research has evaluated multiple novel CKD biomarkers to supplement serum creatinine and proteinuria. The ultimate goal of this research is to find biomarkers that can be used to accurately predict CKD progression and to better time outpatient follow-up, and referral for transplant. Also, an optimal panel of biomarkers can augment the predictive value of proteinuria and serum creatinine by enriching patient enrollment in clinical trials. In this review, we discuss salient findings on 12 candidate plasma and urine biomarkers and their reported association with CKD. We explore the common pathways of CKD progression and the pathophysiologic processes of tubulointerstitial injury, inflammation, repair, and fibrosis that are potentially classified by specific biomarkers. We describe both pediatric and adult findings and highlight the paucity of pediatric research in CKD progression. It will be important for cohorts with longitudinal follow-up to evaluate these CKD biomarkers for potential use in pediatric clinical trials and routine CKD management.

Ameliorative effect of ursolic acid on renal fibrosis in adenine-induced chronic kidney disease in rats

Ursolic acid (UA), an ursane-type pentacyclic triterpenoid commonly found in apple peels and holy basil has been shown to possess many beneficial effects. Renal fibrosis is a complication of kidney injury and associated with increased risk of morbidity and mortality. In our previous investigation, a lupane-type pentacyclic triterpenoid, betulinic acid (BA) was found to have protective effect on chronic kidney disease (CKD) and renal fibrosis. This prompted us to explore the therapeutic value of UA, a chemically related compound to BA in CKD. CKD was induced by feeding adenine with the feed at a concentration of 0.75% for 28 days. UA at the dose rate of 30 mg/kg in 0.5% carboxy methyl cellulose (CMC) was administered by oral route, simultaneously with adenine feeding for 28 days. Adenine feeding increased the kidney weight to body weight index, decreased the kidney function due to injury as indicated by increased markers like serum urea, uric acid, creatinine, cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) and initiated the fibrotic response in kidney by increasing the profibrotic proteins viz. transforming growth factor-beta (TGF-β), connective tissue growth factor (CTGF), fibronectin and collagen. However, treatment with UA reversed the damage induced by adenine as shown by reduced kidney injury and fibrosis markers which was further clearly evident in histological picture indicating the suitability of UA for use in CKD.

Comparison between the effects of hydrochlorothiazide and indapamide on the kidney in hypertensive patients inadequately controlled with losartan

The aim of the study is to compare the effects of hydrochlorothiazide and indapamide on the kidney in patients with hypertension inadequately controlled with losartan. A total of 140 patients who met the criteria and inadequately controlled with losartan 50 mg per day for 2 weeks were randomized in two groups and administered either hydrochlorothiazide 12.5 mg per day (n=70) or indapamide (sustained release) 1.5 mg per day (n=70) in combination with losartan 50 mg per day. Office blood pressure (BP) were collected at baseline and upon each follow-up visit. Creatinine, urine albumin-creatinine ratio (ACR), urine neutrophil gelatinase-associated lipocalin (NGAL) and renal resistive index (RRI) were also collected at baseline and at the 24-week follow-up. None of the baseline characteristics was statistically significantly different between the two groups. After excluding those patients with office BP uncontrolled, 46 patients in the hydrochlorothiazide group (45.7% males, 58.8±10.8 years) and 44 patients in the indapamide group (38.4% males, 61.5±10.9 years) were analysed. There were insignificant changes in creatinine and significant decreases in ACR, NGAL and RRI compared to baseline levels in the two groups. The decrease in ACR (3.8 (0, 28.7) vs 4.2 (0.4, 64.8) mg g^-1, P=0.485) was not significantly different between the two groups, while the decrease in NGAL (16.07±7.07 vs 28.77±7.64 ng ml^-1, P<0.001) and RRI (0.04±0.02 vs 0.07±0.04, P<0.001) was more significant in the indapamide group than in the hydrochlorothiazide group. In conclusion, indapamide is superior to hydrochlorothiazide to improve renal tubular injury and renal haemodynamics in combination with losartan in hypertensive patients with controlled BP.

Urinary neutrophil gelatinase-associated lipocalin as a predictor of cardiovascular events in patients with chronic kidney disease

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular (CV) events. Recently, elevated neutrophil gelatinase-associated lipocalin (NGAL) levels have been reported in patients with heart failure, coronary heart disease, or stroke. Our aim was to assess urinary NGAL as a predictor of CV events in patients with CKD. This was a prospective observational cohort study of 404 patients with predialysis CKD. CV events were defined as CV death, acute coronary syndrome, hospitalization for worsening heart failure, stroke and dissection of aorta. During a mean follow-up period of 33 months, 77 CV events (19.1 %) occurred. After adjustment for gender, age, diabetes, previous cardiovascular disease, urinary albumin/creatinine ratio (UACR), estimated glomerular filtration rate, hemoglobin, and high-sensitivity C-reactive protein, patients with the other quartiles of urinary NGAL had significantly higher risk of CV events compared with patients with the lowest quartile (hazard ratio (HR) 2.81, 95 % confidence interval (CI) 1.01-7.81, P = 0.047 for Q2, HR 3.31, 95 % CI 1.22-9.00, P = 0.019 for Q3, and HR 3.27, 95 % CI 1.15-9.29, P = 0.026 for Q4). Regarding the combination of urinary NGAL with UACR, we also stratified patients into four groups according to whether the level of each marker was above or below the median (61.8 μg per gram creatinine (gCr) for NGAL and 351.1 mg/gCr for UACR). Four-year CV event-free survival rates were 89.2, 79.6, 71.8, and 51.5 % in order for the four respective groups (P < 0.0001). Elevated urinary NGAL was able to predict future CV events in CKD patients, and had incremental predictive value with elevated UACR.

Measurement of renal function in patients with chronic kidney disease

Chronic kidney disease affects millions of people worldwide and is associated with an increased morbidity and mortality as a result of kidney failure and cardiovascular disease. Accurate assessment of kidney function is important in the clinical setting as a screening tool and for monitoring disease progression and guiding prognosis. In clinical research, the development of new methods to measure kidney function accurately is important in the search for new therapeutic targets and the discovery of novel biomarkers to aid early identification of kidney injury. This review considers different methods for measuring kidney function and their contribution to the improvement of detection, monitoring and treatment of chronic kidney disease.

Cardio-renal syndrome: new perspective in diagnostics

Chronic heart failure and chronic renal failure are at epidemic proportions. These patients have significantly altered cardiac, renal, and all-cause outcomes. Much of the current research has focused on treating these individual organs in isolation. Although there are positive data on outcomes with neurohormonal modulation, they, however, remain underused. At present, data lacks for novel treatment options, while evidence continues to point at significantly worsened prognosis. Current diagnostic tools that detect acute changes in renal function or renal injury appear retrospective, which often hinder meaningful diagnostic and therapeutic decisions. This review is aimed at exploring the importance of accurate assessment of renal function for the heart failure patient by providing a synopsis on cardio-renal physiology and establishing the possibility of novel approaches in bridging the divide.

Small lipid-binding proteins in regulating endothelial and vascular functions: focusing on adipocyte fatty acid binding protein and lipocalin-2

Dysregulated production of adipokines from adipose tissue plays a critical role in the development of obesity-associated cardiovascular abnormalities. A group of adipokines, including adipocyte fatty acid binding protein (A-FABP) and lipocalin-2, possess specific lipid-binding activity and are up-regulated in obese human subjects and animal models. They act as lipid chaperones to promote lipotoxicity in endothelial cells and cause endothelial dysfunction under obese conditions. However, different small lipid-binding proteins modulate the development of vascular complications in distinctive manners, which are partly attributed to their specialized structural features and functionalities. By focusing on A-FABP and lipocalin-2, this review summarizes recent advances demonstrating the causative roles of these newly identified adipose tissue-derived lipid chaperones in obesity-related endothelial dysfunction and cardiovascular complications. The specific lipid-signalling mechanisms mediated by these two proteins are highlighted to support their specialized functions. In summary, A-FABP and lipocalin-2 represent potential therapeutic targets to design drugs for preventing vascular diseases associated with obesity.

LINKED ARTICLES

This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3.

Acute kidney injury in childhood: should we be worried about progression to CKD?

While emerging evidence indicates that the incidence of both acute kidney injury (AKI) and chronic kidney disease (CKD) in children is rising and that the etiologies are dramatically changing, relatively little is currently known regarding the potential for transition from AKI to CKD. Major barriers to assessing for a potential AKI to CKD link have included lack of a standard pediatric AKI definition, narrow focus only on children with AKI who receive renal replacement therapy, and reliance on serum creatinine as the main biomarker to detect and diagnose AKI and CKD. Recent data have validated a multi-dimensional AKI classification system for children and have suggested chronic kidney sequelae in pediatric populations with AKI or at risk for AKI. In addition, a number of novel AKI biomarkers are being rigorously validated as early indicators of incipient CKD. Our goals for this article are to (1) review the recent changes in pediatric AKI and CKD epidemiology, (2) explore the evidence for a potential AKI to CKD link, and (3) propose new clinical and research paradigms to better elucidate the progression from AKI to CKD.

The use of targeted biomarkers for chronic kidney disease

There is a paucity of sensitive and specific biomarkers for the early prediction of CKD progression. The recent application of innovative technologies such as functional genomics, proteomics, and biofluid profiling has uncovered several new candidates that are emerging as predictive biomarkers of CKD. The most promising among these include urinary proteins such as neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and liver-type fatty acid binding protein. In addition, an improved understanding of the complex pathophysiologic processes underlying CKD progression has also provided discriminatory biomarkers of CKD progression that are being actively evaluated. Candidates included in this category are plasma proteins such as asymmetric dimethylarginine, adiponectin, apolipoprotein A-IV, fibroblast growth factor 23, neutrophil gelatinase-associated lipocalin, and the natriuretic peptides, as well as urinary N-acetyl-β-d-glucosaminidase. This review represents a critical appraisal of the current status of these emerging CKD biomarkers. Currently, none of these are ready for routine clinical use. Additional large, multicenter prospective studies are needed to validate the biomarkers, identify thresholds and cut-offs for prediction of CKD progression and adverse events, assess the effects of confounding variables, and establish the ideal assays.

Neutrophil gelatinase-associated lipocalin levels in patients with crohn disease undergoing treatment with infliximab

Increased levels of neutrophil gelatinase-associated lipocalin (NGAL), a small 25-kd stress protein released by several injured cells, have been reported in different pathological conditions such as kidney and chronic inflammatory bowel diseases. As NGAL is also emerging as a biomarker for monitoring the response to different types of treatment, the aims of this pilot study were to analyze urinary NGAL levels in a small cohort of patients affected by Crohn disease and to evaluate the eventual impact of the intravenous administration of infliximab on these levels.Crohn disease patients presented increased NGAL values compared with controls (210.5 ng/mL [88.3-1100.0 ng/mL] vs 7.6 [4.4] ng/mL; P = 0.001); the infusion of a single high dose of infliximab induced an impressive reduction in these levels to 80.1 ng/mL (38.6-400.2 ng/mL; P = 0.006) with a mean reduction ratio of 62.1%. These findings suggest a pivotal role of NGAL in the systemic adaptations to Crohn disease, also confirming the potential usefulness of NGAL measurement in the evaluation of early responses to therapy or in predicting different clinical outcomes.