Urinary Biomarkers of Aminoglycoside-Induced Nephrotoxicity in Cystic Fibrosis: Kidney Injury Molecule-1 and Neutrophil Gelatinase-Associated Lipocalin

Cystic fibrosis-related kidney disease-emerging morbidity and disease modifier

Cystic fibrosis (CF) is a life-shortening multisystem disease resulting from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, causing the most devastating phenotypes in the airway and pancreas. Significant advances in treatment for CF lung disease, including the expanded use of high-efficiency modulator therapies (HEMT) such as Trikafta, have dramatically increased both quality of life and life expectancy for people with CF (PwCF). With these advances, long-term extrapulmonary manifestations are more frequently recognized. Pseudo-Barter syndrome, acute kidney injury (AKI) induced by medications or dehydration, amyloidosis, nephrolithiasis, and IgA and diabetic nephropathies have been previously reported in PwCF. Newer data suggest that chronic kidney disease (CKD) is a new morbidity in the aging CF population, affecting 19% of people over age 55. CKD carries a high risk of premature death from cardiovascular complications. Studies suggest that CFTR dysfunction increases kidneys' vulnerability to injury caused by the downstream effects of CF. Improving the mutant CFTR function by HEMT may help to tease apart the kidney responses resulting from extrinsic factors and those intrinsically related to the CFTR gene mutations. Additionally, given the novelty of HEMT approaches, the potential off-target effects of their long-term use are currently unknown. We review the evolving kidney complications in PwCF and propose the term CF-related kidney disease. We hope this review will increase awareness about the changing phenotype of kidney dysfunction in PwCF and help prevent morbidity related to this condition.

Ameliorative and protective effects of coenzyme Q10 against natural and chemical toxicity: a narrative review

Coenzyme Q10 (CoQ10) or ubiquinone is the most known dietary and nutritional supplementation, which has various functions in the body such as involvement in adenosine triphosphate production, modulation of gene expression, antioxidant, and anti-inflammatory effects. It has been indicated that it is useful against cardiotoxicity, hepatotoxicity, neurotoxicity, nephrotoxicity, and so on, which are induced by various toxicants. In this review, we selected articles that include the protective effects of CoQ10 against the toxicity of various chemical and natural compounds including pharmaceuticals, metals, pesticides, etc. Scientific databases including PubMed/Medline, Science Direct, Scopus, and Google Scholar were searched to find relevant in vitro and in vivo studies. The underlying protective mechanisms for CoQ10 against natural and chemical compound toxicity included the enhancement of antioxidant enzyme activities such as superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, and suppression of pro-inflammatory markers such as tumor necrosis factor-alpha, interleukin-1, and IL-6. Furthermore, it has anti-apoptotic potential by regulating the B-cell lymphoma, Bcl-2-associated X protein, and caspase3/9. Overall, these properties make CoQ10 a highly fascinating compound that may contribute to different aspects of health.

Lung-Kidney Axis in Cystic Fibrosis: Early Urinary Markers of Kidney Injury Correlate with Neutrophil Activation and Worse Lung Function

Background

Adult people with cystic fibrosis (PwCF) have a higher risk of end-stage kidney disease than the general population. The nature and mechanism of kidney disease in CF are unknown. This study quantifies urinary kidney injury markers and examines the hypothesis that neutrophil activation and lung infection are associated with early kidney injury in CF.

Methods

Urinary total protein, albumin, and markers of kidney injury and neutrophil activation, normalized to creatinine, as well as urinary immune cells, were quantified in CF (n = 48) and healthy (n = 33) cohorts. Infection burden and chronicity were defined by sputum culture and serum titers of anti-bacterial antibodies.

Results

PwCF had increased urinary protein levels, consisting of low-molecular-weight tubular injury markers, independent of glomerular filtration rate (eGFR). This finding suggests subclinical renal injury processes. Urinary analysis of the CF cohort identified different associations of urinary injury markers with aminoglycoside exposure, lung function, and neutrophil activation. High urinary KIM-1 levels and increased prevalence of neutrophils among urine immune cells correlated with decreased lung function in PwCF. The relationship between tubular injury and decreased lung function was most prominent in patients harboring chronic Pseudomonas aeruginosa infection.

Conclusions

Increased urinary tubular injury markers in PwCF suggest early subclinical renal injury not readily detected by eGFR. The strong association of high urinary KIM-1 and neutrophils with diminished lung function and high Pseudomonas aeruginosa burden suggests that pulmonary disease may contribute to renal injury in CF.

Unveiling drug induced nephrotoxicity using novel biomarkers and cutting-edge preventive strategies

Drug-induced nephrotoxicity is still a significant obstacle in pharmacotherapy of various diseases and it accounts for around 25 % of serious side-effects reported after drug administration. Furthermore, some groups of drugs such as nonsteroidal anti-inflammatory drugs, antibiotics, antiviral drugs, antifungal drugs, immunosuppressants, and chemotherapeutic drugs have the "preference" for damaging the kidney and are often referred to as the kidney's "silent killer". Clinically, the onset of acute kidney injury associated with drug administration is registered in approximately 20 % of patients and many of them develop chronic kidney disease vulnerability. However, current knowledge about the mechanisms underlying this dangerous phenomenon is still insufficient with many unknowns. Hence, the valuable use of these drugs in clinical practice is significantly limited. The main aim of this study is to draw attention to commonly prescribed nephrotoxic drugs by clinicians or drugs bought over the counter. In addition, the complex relationship between immunological, vascular and inflammatory events that promote kidney damage is discussed. The practical use of this knowledge could be implemented in the engineering of novel biomarkers for early detection of drug-associated kidney damage such as Kidney Injury Molecule (KIM-1), lipocalin associated with neutrophil gelatinase (NGAL) and various microRNAs. In addition, the utilization of artificial intelligence (AI) for the development of computer algorithms that could detect kidney damage at an early stage should be further explored. Therefore, this comprehensive review provides a new outlook on drug nephrotoxicity that opens the door for further clinical research of novel potential drugs or natural products for the prevention of drug-induced nephrotoxicity and accessible education.

Overview of Antibiotic-Induced Nephrotoxicity

Drug-induced nephrotoxicity accounts for up to 60% of cases of acute kidney injury (AKI) in hospitalized patients and is associated with increased morbidity and mortality in both adults and children. Antibiotics are one of the most common causes of drug-induced nephrotoxicity. Mechanisms of antibiotic-induced nephrotoxicity include glomerular injury, tubular injury or dysfunction, distal tubular obstruction from casts, and acute interstitial nephritis (AIN) mediated by a type IV (delayed-type) hypersensitivity response. Clinical manifestations of antibiotic-induced nephrotoxicity include acute tubular necrosis (ATN), AIN, and Fanconi syndrome. Given the potential nephrotoxic effects of antibiotics on critically ill patients, the use of novel biomarkers can provide information to optimize dosing and duration of treatment and can help prevent nephrotoxicity when traditional markers, such as creatinine, are unreliable. Use of novel kidney specific biomarkers, such as cystatin C and urinary kidney injury molecule-1 (KIM-1), may result in earlier detection of AKI, dose adjustment, or discontinuation of antibiotic and development of nonnephrotoxic antibiotics.

Role of urinary NGAL and microalbuminuria in the detection of subclinical acute kidney injury in pediatric intensive care unit and diabetic children

Subclinical Acute Kidney Injury (AKI) describes patients who did not fulfill the classical criteria for AKI diagnosis but showed elevated levels of new biomarkers reflecting tubular injury. One of these biomarkers is Neutrophil Gelatinase-Associated Lipocalin (NGAL). The aim of this study is to investigate the role of urinary NGAL and microalbuminuria as non-invasive biomarkers in the detection of subclinical AKI. Analysis of urinary NGAL and microalbuminuria in 91 subjects [30 pediatric intensive care unit (PICU) patients, 31 diabetic patients and 30 healthy controls] recruited from Cairo University Pediatric Hospital was done. Our study revealed that urinary NGAL was significantly higher in the PICU group followed by the diabetic group and lowest in the controls group (p=0.022). A positive correlation was found between urinary NGAL and microalbuminuria in the PICU group (Rvalue= 0.585, p-value=0.001). In diabetic group, a positive correlation was found between urinary NGAL and fasting blood glucose, 2 hours post prandial and HbA1C (R-value=0.421; pvalue= 0.021; R-value=0.426; p-value=0.019; R-value=0.438; pvalue= 0.018 respectively). Urinary NGAL may be a potential biomarker to detect subclinical AKI before actual functional renal damage leading to early intervention and reduction of mortality.

Renal Function in Patients with Cystic Fibrosis: A Single-Center Study

Cystic fibrosis (CF) is the most common incurable autosomal recessive disease affecting the Caucasian population. As the prognosis for life extension of CF patients improves, co-morbidities, including kidney disease, become more common. Identifying those at the highest risk of kidney injury is therefore extremely important. The aim of this study was to evaluate the biomarkers of renal function in 50 CF patients using the estimated glomerular filtration rate (eGFR) based on creatinine and cystatin C equation as well as serum creatinine (sCr), serum cystatin C (CysC), serum urea and urinary neutrophil gelatinase-associated lipocalin (uNGAL) concentrations. sCr, CysC, urea and uNGAL were estimated. eGFR was calculated according to the CKD-EPI formula. CysC was significantly increased, while eGFR was significantly lower in the CF group than in the controls (p < 0.001 and p < 0.01, respectively). There was no significant difference in the sCr, urea and uNGAL concentrations between patients with CF and healthy subjects. For the purpose of our analysis, in order to assess renal function in patients with CF in clinical practice, the concentration of serum CysC and eGFRCKD-EPI should be determined. Patients with CF presented with renal function impairment pictured by increased serum CysC and decreased eGFR values compared to controls. Unchanged uNGAL concentrations suggested preserved tubular function despite aminoglycoside treatment. Further prospective studies are needed to clarify whether kidney impairment observed in the course of CF progresses.

Could urinary kidney injury molecule-1 be a good marker in subclinical acute kidney injury in mild to moderate COVID-19 infection?

PURPOSE

To evaluate urinary kidney injury molecule-1 (uKIM-1), which is a proximal tubule injury biomarker in subclinical acute kidney injury (AKI) that may occur in COVID-19 infection.

METHODS

The study included proteinuric (n = 30) and non-proteinuric (n = 30) patients diagnosed with mild/moderate COVID-19 infection between March and September 2020 and healthy individuals as a control group (n = 20). The uKIM-1, serum creatinine, cystatin C, spot urine protein, creatinine, and albumin levels of the patients were evaluated again after an average of 21 days.

RESULTS

The median (interquartile range) uKIM-1 level at the time of presentation was 246 (141-347) pg/mL in the proteinuric group, 83 (29-217) pg/mL in the non-proteinuric group, and 55 (21-123) pg/mL in the control group and significantly high in the proteinuric group than the others (p < 0.001). Creatinine and cystatin C were significantly higher in the proteinuric group than in the group without proteinuria, but none of the patients met the KDIGO-AKI criteria. uKIM-1 had a positive correlation with PCR, non-albumin proteinuria, creatinine, cystatin C, CRP, fibrinogen, LDH, and ferritin, and a negative correlation with eGFR and albumin (p < 0.05). In the multivariate regression analysis, non-albumin proteinuria (p = 0.048) and BUN (p = 0.034) were identified as independent factors predicting a high uKIM-1 level. After 21 ± 4 days, proteinuria regressed to normal levels in 20 (67%) patients in the proteinuric group. In addition, the uKIM-1 level, albuminuria, non-albumin proteinuria, and CRP significantly decreased.

CONCLUSIONS

Our findings support that the kidney is one of the target organs of the COVID-19 and it may cause proximal tubule injury even in patients that do not present with AKI or critical/severe COVID-19 infection.

The use of diagnostic tools for pediatric AKI: applying the current evidence to the bedside

Given the known deleterious consequences of acute kidney injury (AKI), exciting recent research efforts have focused on developing strategies for the earlier recognition of AKI in the pediatric population. Recognizing the limitations of serum creatinine, investigators have focused on the study of novel biomarkers and practical bedside tools for identifying patients at risk for AKI prior to a rise in serum creatinine. In PubMed, there are presently over 30 original research papers exploring the use of pediatric AKI risk prediction tools in just the last 2 years. The following review highlights the most recent advances in the literature regarding opportunities to refine our ability to detect AKI early. Importantly, this review discusses how prediction tools including novel urine and serum biomarkers, practical risk stratification tests, renal functional reserve, and electronic medical record alerts may ultimately be applied to routine clinical practice.

Agomelatine prevents gentamicin nephrotoxicity by attenuating oxidative stress and TLR-4 signaling, and upregulating PPARγ and SIRT1

Kidney injury is a relatively common complication of the use of aminoglycosides. Inflammation and oxidative stress play a key role in gentamicin (GM) nephrotoxicity. We investigated the protective effect of the melatonergic agonist agomelatine (AGM) on GM nephrotoxicity, emphasizing the involvement of TLR-4 signaling, SIRT1 and PPARγ. Rats received 25 mg/kg AGM for 15 days and 100 mg/kg GM for eight days starting at day 7. Elevated serum creatinine, urea and Kim-1 along with multiple histological alterations in the kidney were observed in GM-intoxicated rats. Malondialdehyde (MDA), TNF-α, IL-1β, nitric oxide (NO) and myeloperoxidase (MPO) were increased, and GSH, SOD and catalase were decreased in the kidney of GM-intoxicated rats. Treatment with AGM significantly ameliorated the kidney function biomarkers, prevented tissue injury, decreased inflammatory cytokines, MDA, NO and MPO, and boosted antioxidants. In addition, AGM suppressed the expression of TLR-4, NF-κB p65, p38 MAPK, ERK-1, VCAM-1 and iNOS, whereas upregulated SIRT1 and PPARγ in the kidney of GM-intoxicated rats. In conclusion, AGM prevented GM nephrotoxicity in rats by attenuating oxidative injury and inflammation. AGM suppressed TLR-4 signaling, enhanced antioxidants and upregulated SIRT1 and PPARγ in the kidney of GM-induced rats.

Exposure to an Extended-Interval, High-Dose Gentamicin Regimen in the Neonatal Period Is Not Associated With Long-Term Nephrotoxicity

Objectives: To assess the association between gentamicin exposure and subclinical signs of nephrotoxicity in school children who were exposed to a high-dose gentamicin regimen in the neonatal period. Methods: Children receiving three or more doses (6 mg/kg) of gentamicin as neonates were invited to a follow-up in school age. We evaluated potential signs of subclinical nephrotoxicity with four validated urine biomarkers: protein-creatinine ratio (PCR), albumin-creatinine ratio (ACR), kidney injury molecule-1 (KIM-1), and N-acetyl-beta-D-glucosaminidase (NAG) normalized for urine creatinine (NAG-Cr). In addition, blood pressure was measured. The measures of gentamicin exposure were cumulative dose (mg/kg) and highest trough plasma concentration (TPC) in mg/L. We used logistic and linear regression and non-parametric kernel regression to analyze the relationship between gentamicin exposure and the urine biomarkers. Results: A total of 222 gentamicin exposed children were included. As neonates, the children were exposed to a median (interquartile range-IQR) cumulative gentamicin dose of 36 (26-42) mg/kg and the median (IQR) TPC was 1.0 (0.7-1.3) mg/L. At follow-up, 15 children (6.8%) had either one abnormal urine biomarker value (13 children) or two abnormal urine biomarker values (2 children). These 17 biomarker values were all marginally above the suggested upper cutoff, and included the following markers; KIM-1 (n = 2), NAC-Cr (n = 5), ACR (n = 6), and PCR (n = 4). All other 207 children had normal sets of all four urine biomarkers. One child had hypertension. There were no differences in gentamicin exposure, gestational age (GA) at birth or birth weight between the group of 15 children with one or two abnormal urine biomarker values compared to the other 207 children who had normal biomarker values. Using different regression analyses, we did not find any association between gentamicin exposure (cumulative dose and/or TPC) and the urine biomarker values. Conclusions: Exposure to an extended-interval, high-dose gentamicin regimen in the neonatal period was not associated with signs of subclinical nephrotoxicity in schoolchildren. We therefore suggest that the gentamicin treatment regimen evaluated in this study is safe in terms of long-term nephrotoxicity. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT03253614.

Tubular injury and cell-cycle arrest biomarkers to predict acute kidney injury in noncritically ill children receiving aminoglycosides

Aim: NGAL, IL-18, KIM-1 as well as urinary TIMP2 and IGFBP7 and their mathematical product (TIMP2*IGFBP7) were evaluated for detecting pediatric aminoglycoside acute kidney injury (AG-AKI). Methods: In a prospective study, noncritically ill children received aminoglycosides (AG) ≥3 days. The area under the curve (AUC) for biomarkers to detect AKI was calculated by a) days before AKI onset; b) treatment days. Results: There were 113 AG episodes (68% febrile neutropenia). The AKI group had a higher proportion with febrile neutropenia. The AKI group had significantly lower NGAL 3 days before AKI, as patients with febrile neutropenia had a lower NGAL during AG treatment (p < 0.05). NGAL, IL-18 and TIMP2*IGFBP7 had AUC ≥0.73 at 3, 2 and 2 days before AKI onset. Conclusion: NGAL, IL-18 and TIMP2*IGFBP7 were modest early biomarkers of AG-AKI. Febrile neutropenia was associated with lower NGAL.

A randomised controlled trial of rosuvastatin for the prevention of aminoglycoside-induced kidney toxicity in children with cystic fibrosis

The PROteKT study tested the hypothesis that rosuvastatin can inhibit aminoglycoside-induced nephrotoxicity in children with Cystic Fibrosis (CF). This open label, parallel group, randomised controlled trial recruited children and young people aged 6 to 18 years with CF at 13 paediatric CF treatment centres in the UK. Participants were randomised equally to either receive oral rosuvastatin (10 mg once daily) or no intervention (control) throughout clinically indicated treatment with intravenous tobramycin. The primary outcome was the difference between the groups in mean fold-change in urinary Kidney Injury Molecule-1 (KIM-1). Fifty (rosuvastatin n = 23, control n = 27) participants were recruited between May 2015 and January 2017. Primary outcome data was available for 88% (rosuvastatin n = 20, control n = 24). The estimated mean treatment difference in the geometric mean-fold change of normalised KIM-1 was 1.08 (95% CI 0.87–1.35, p = 0.48). In total there were 12 adverse reactions, all mild, reported by five participants randomised to rosuvastatin, and one serious adverse event in each group. Whilst no protective effect of rosuvastatin was seen, there was a lower than expected level of nephrotoxicity in the cohort. Therefore, we can neither confirm nor refute the hypothesis that rosuvastatin protects against aminoglycoside nephrotoxicity.

Protective effects of pharmacological agents against aminoglycoside-induced nephrotoxicity: A systematic review

Introduction: Aminoglycosides have been long used for antibacterial treatment and are still commonly used in clinical practice. Despite their extensive application and positive effects, drug-related toxicity is considered as the main obstacle for aminoglycosides. Aminoglycosides induce nephrotoxicity through the endocytosis and accumulation of the antibiotics in the epithelial cells of proximal tubule. Most importantly, however, a number of pharmacological agents were demonstrated to have protective activities against nephrotoxicity in experimental animals.Areas covered: In the present systematic review, the authors provide and discuss the mechanisms and epidemiological features of aminoglycoside-induced nephrotoxicity, and focus mainly on recent discoveries and key features of pharmacological interventions. In total, 39 articles were included in this review.Expert opinion: The majority of studies investigated gentamicin-induced nephrotoxicity in animal models. Antioxidants, chemicals, synthetic drugs, hormones, vitamins, and minerals showed potential values to prevent gentamicin-induced nephrotoxicity. Indicators used to evaluate the effectiveness of nephroprotection included antioxidative indexes, inflammatory responses, and apoptotic markers. Among the nephroprotective agents studied, herbs and natural antioxidant agents showed excellent potential to provide a protective strategy against gentamicin-induced nephrotoxicity.

High-sensitivity C-reactive protein as a predictive factor of acute kidney injury following aneurysmal subarachnoid hemorrhage: a prospective observational study

BACKGROUND

High-sensitivity C-reactive protein (hs-CRP) is a well-recognized biomarker of neurologic complications and clinical outcome of stroke patients. However, whether hs-CRP can predict the occurrence of acute kidney injury (AKI) in aneurysmal subarachnoid hemorrhage (aSAH) patients is still unclear. The objective of this study was to assess the feasibility of using serum hs-CRP level to predict the occurrence of AKI in aSAH patients.

METHODS

One hundred sixty-four aSAH patients were enrolled into a prospective observational study. AKI was diagnosed using the modified Kidney Disease Improving Global Outcomes (KDIGO) standard. The relationship between serum hs-CRP level at admission and occurrence of AKI was analyzed.

RESULTS

AKI occurred in 17 patients (10.4%) in this cohort. Patients with AKI had significantly higher hs-CRP levels than those without. The mortality of the AKI group tends to be higher than that of the non-AKI group, but the difference was not statistically significant (4/17 (23.5%) vs. 13/147 (8.8%), P = 0.081). After adjusting for possible confounding factors including World Federation of Neurosurgical Societies grade, diabetes, and serum creatinine, multivariate analysis revealed that serum hs-CRP level and antibiotic therapy were both significant factors independently associated with AKI following aSAH (serum hs-CRP: OR = 1.2, 95% confidence interval (CI) = 1.1-1.3, P = 0.003; antibiotic therapy: OR = 5.8, 95%CI = 1.6-20.7, P = 0.007). Receiver operating characteristic curve analysis showed that hs-CRP had a sensitivity of 76.5% and a specificity of 64.6% for predicting the development of AKI on the basis of the best thresholds. The post hoc log-rank test revealed that patients having serum hs-CRP level > 6.6 mg/L had a significantly higher AKI rate than patients having serum hs-CRP level ≤ 6.6 mg/L (P = 0.001).

CONCLUSIONS

Serum hs-CRP level might be helpful as a predictor for the development of AKI in aSAH patients. Delayed cerebral ischemia occurrence rate and mortality of patients with AKI tend to be higher than those of patients without in this cohort; however, they were not significantly different.

Sepsis associated acute kidney injury

Sepsis is defined as organ dysfunction resulting from the host's deleterious response to infection. One of the most common organs affected is the kidneys, resulting in sepsis associated acute kidney injury (SA-AKI) that contributes to the morbidity and mortality of sepsis. A growing body of knowledge has illuminated the clinical risk factors, pathobiology, response to treatment, and elements of renal recovery that have advanced our ability to prevent, detect, and treat SA-AKI. Despite these advances, SA-AKI remains an important concern and clinical burden, and further study is needed to reduce the acute and chronic consequences. This review summarizes the relevant evidence, with a focus on the risk factors, early recognition and diagnosis, treatment, and long term consequences of SA-AKI. In addition to literature pertaining to SA-AKI specifically, pertinent sepsis and acute kidney injury literature relevant to SA-AKI was included.

Subclinical AKI: ready for primetime in clinical practice?

There has been considerable progress over the last decade in the standardization of the acute kidney injury (AKI) definition with the publication of the RIFLE, AKIN, KDIGO and ERBP classification criteria. However, these classification criteria still rely on imperfect parameters such as serum creatinine and urinary output. The use of timed urine collections, kinetic eGFR (estimated glomerular filtration rate), real time measurement of GFR and direct measures of tubular damage can theoretically aid in a more timely diagnosis of AKI and improve patients' outcome. There has been an extensive search for new biomarkers indicative of structural tubular damage but it remains controversial whether these new markers should be included in the current classification criteria. The use of these markers has also led to the creation of a new concept called subclinical AKI, a condition where there is an increase in biomarkers but without clinical AKI, defined as an increase in serum creatinine and/or a decrease in urinary output. In this review we provide a framework on how to critical appraise biomarker research and on how to position the concept of subclinical AKI. The evaluation of biomarker performance and the usefulness of the concept 'subclinical AKI' requires careful consideration of the context these biomarkers are used in (clinical versus research setting) and the goal we want to achieve (risk assessment versus prediction versus early diagnosis versus prognostication). It remains currently unknown whether an increase in biomarkers levels without functional repercussion is clinically relevant and whether including biomarkers in classification criteria will improve patients' outcome.