Drug-induced nephropathy: an update

Past, Present, and Future Biomarkers of Kidney Function and Injury: The Relationship With Antibiotics

Routinely used kidney biomarkers of injury and function such as serum creatinine and urine albumin to creatinine ratio, are neither sensitive nor specific. Future biomarkers are being developed for clinical use and have already been included in guidance from groups such as the U.S. Food and Drug Administration and the Predictive Safety Testing Consortium. These biomarkers have important implications for early identification of kidney injury and more accurate measurement of kidney function. Many antibiotics are either eliminated by the kidney or can cause clinically significant nephrotoxicity. As a result, clinicians should be familiar with new biomarkers of kidney function and injury, their place in clinical practice, and applications for antibiotic dosing.

First analytical confirmation of drug-induced crystal nephropathy in felines caused by GS-441524, the active metabolite of Remdesivir

GS-441524 is an adenosine nucleoside antiviral demonstrating significant efficacy in the treatment of feline infectious peritonitis (FIP), an otherwise fatal illness, resulting from infection with feline coronavirus. However, following the emergence of COVID-19, veterinary development was halted, and Gilead pursued clinical development of a GS-441524 pro-drug, resulting in the approval of Remdesivir under an FDA emergency use authorization. Despite lack of regulatory approval, GS-441524 is available without a prescription through various unlicensed online distributors and is commonly purchased by pet owners for the treatment of FIP. Herein, we report data obtained from the analytical characterization of two feline renal calculi, demonstrating the propensity for GS-441524 to cause renal toxicity through drug-induced crystal nephropathy in vivo. As definitive diagnosis of drug-induced crystal nephropathy requires confirmation of the lithogenic material to accurately attribute a mechanism of toxicity, renal stone composition and crystalline matrix were characterized using ultra-performance liquid chromatography photodiode array detection (UPLC-PDA), ultra-performance liquid chromatography mass spectrometry (LCMS), nuclear magnetic resonance (NMR) spectroscopy, X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). This work serves to provide the first analytical confirmation of GS-441524-induced crystal nephropathy in an effort to support toxicologic identification of adverse renal effects caused by administration of GS-441524 or any pro-drug thereof.

Time Series AI Model for Acute Kidney Injury Detection Based on a Multicenter Distributed Research Network: Development and Verification Study

Background

Acute kidney injury (AKI) is a marker of clinical deterioration and renal toxicity. While there are many studies offering prediction models for the early detection of AKI, those predicting AKI occurrence using distributed research network (DRN)-based time series data are rare.

Objective

In this study, we aimed to detect the early occurrence of AKI by applying an interpretable long short-term memory (LSTM)-based model to hospital electronic health record (EHR)-based time series data in patients who took nephrotoxic drugs using a DRN.

Methods

We conducted a multi-institutional retrospective cohort study of data from 6 hospitals using a DRN. For each institution, a patient-based data set was constructed using 5 drugs for AKI, and an interpretable multivariable LSTM (IMV-LSTM) model was used for training. This study used propensity score matching to mitigate differences in demographics and clinical characteristics. Additionally, the temporal attention values of the AKI prediction model's contribution variables were demonstrated for each institution and drug, with differences in highly important feature distributions between the case and control data confirmed using 1-way ANOVA.

Results

This study analyzed 8643 and 31,012 patients with and without AKI, respectively, across 6 hospitals. When analyzing the distribution of AKI onset, vancomycin showed an earlier onset (median 12, IQR 5-25 days), and acyclovir was the slowest compared to the other drugs (median 23, IQR 10-41 days). Our temporal deep learning model for AKI prediction performed well for most drugs. Acyclovir had the highest average area under the receiver operating characteristic curve score per drug (0.94), followed by acetaminophen (0.93), vancomycin (0.92), naproxen (0.90), and celecoxib (0.89). Based on the temporal attention values of the variables in the AKI prediction model, verified lymphocytes and calcvancomycin ium had the highest attention, whereas lymphocytes, albumin, and hemoglobin tended to decrease over time, and urine pH and prothrombin time tended to increase.

Conclusions

Early surveillance of AKI outbreaks can be achieved by applying an IMV-LSTM based on time series data through an EHR-based DRN. This approach can help identify risk factors and enable early detection of adverse drug reactions when prescribing drugs that cause renal toxicity before AKI occurs.

[Cancer imaging and prevention of renal failure]

The risk of acute renal failure (ARF) following iodinated contrast media injection has long been overestimated because of the previous use of more toxic ICPs and uncontrolled studies. Nowadays, this concept is being questioned. Patients with severe renal failure and/or ARF are the only group still considered at risk. In these patients, it is necessary to discuss an alternative without an iodinated contrast agent. Contrast-enhanced ultrasound, MRI, spectral CT or PET-CT scan can be used instead of contrast-enhanced CT. Preventive measures should be applied when appropriate substitute to CT is not available or not diagnosed (minimum necessary dose of ICP, interruption of some treatments and prior hydration). These recommendations formalized by the European Society of Urogenital Radiology (ESUR) in 2018 address most situations faced by clinicians. In complex situations, an opinion from a nephrologist remains necessary after asking the radiologist about the availability of acceptable substitutes.

Drug induced nephrotoxicity- A mechanistic approach

The main goal of the treatment of patients is its effectiveness and safety. However, all currently prescribed drugs being used also have certain adverse effects, which might be seen as an unavoidable but necessary cost of pharmacotherapy. The kidney is the primary organ for xenobiotics elimination, making it particularly susceptible to the harmful effects of drugs and their metabolites during their excretion from the body. Moreover, certain medications have a preferential nephrotoxicity potential, which means that using them increases the risk of kidney injury. Drug nephrotoxicity is, therefore, both a significant problem and a complication of pharmacotherapy. It should be noted that, there is presently no accepted definition of drug-induced nephrotoxicity and no established diagnostic criteria. The current review briefly describes the pathogenic mechanism of drug-induced nephrotoxicity, the various basic drugs with nephrotoxicity potential and the renal biomarkers for the treatment of the drug-related kidney damage.

A Multichannel Fluorescent Array Sensor for Discrimination of Different Types of Drug-Induced Kidney Injury

The differences in urinary proteins could provide a novel opportunity to distinguish the different types of drug-induced kidney injury (DIKI). In this research, Au nanoparticles-polyethyleneimine (AuNPs-PEI) and the three fluorophore-labeled proteins (FLPs) have been constructed as a multichannel fluorescent array sensor via electrostatic interaction, which was used to detect the subtle changes in urine collected from the pathological state of DIKI. Once the urine from different types of DIKI was introduced, the binding equilibrium between AuNPs-PEI and FLPs would be broken due to the competitive binding of urinary protein, and the corresponding fluorescence response pattern would be generated. Depending on the different fluorescence response patterns, the different types of DIKI were successfully identified by principal component analysis (PCA) and linear discriminant analysis (LDA). Accordingly, the strategy was expected to be a powerful technique for evaluating the potential unclear mechanisms of nephrotoxic drugs, which would provide a promising method for screening potential renal-protective drugs.

Mechanisms of Piperacillin/Tazobactam Nephrotoxicity: Piperacillin/Tazobactam-Induced Direct Tubular Damage in Mice

Piperacillin/tazobactam (PT) is one of the most commonly prescribed antibiotics for critically ill patients in intensive care. PT has been reported to cause direct nephrotoxicity; however, the underlying mechanisms remain unknown. We investigated the mechanisms underlying PT nephrotoxicity using a mouse model. The kidneys and sera were collected 24 h after PT injection. Serum blood urea nitrogen (BUN), creatinine, neutrophil gelatinase-associated lipocalin (NGAL), and renal pathologies, including inflammation, oxidative stress, mitochondrial damage, and apoptosis, were examined. Serum BUN, creatinine, and NGAL levels significantly increased in PT-treated mice. We observed increased IGFBP7, KIM-1, and NGAL expression in kidney tubules. Markers of oxidative stress, including 8-OHdG and superoxide dismutase, also showed a significant increase, accompanied by mitochondrial damage and apoptosis. The decrease in the acyl-coA oxidase 2 and Bcl2/Bax ratio also supports that PT induces mitochondrial injury. An in vitro study using HK-2 cells also demonstrated mitochondrial membrane potential loss, indicating that PT induces mitochondrial damage. PT appears to exert direct nephrotoxicity, which is associated with oxidative stress and mitochondrial damage in the kidney tubular cells. Given that PT alone or in combination with vancomycin is the most commonly prescribed antibiotic in patients at high risk of acute kidney injury, caution should be exercised.

Mitochondrial Toxic Effects of Antiepileptic Drug Valproic Acid on Mouse Kidney Stem Cells

Valproic acid (VPA) is a histone deacetylase inhibitor that is used mainly as an antiepileptic and anticonvulsant drug. The side effects of VPA usually appears as hepatic injury and various metabolic disorders. On the other hand, it is rarely reported to cause kidney injury. Despite the many studies on the influence of VPA exposure on the kidneys, the specific mechanism remains unclear. This study examined the changes after VPA treatment to the mouse kidney stem cells (mKSCs). VPA triggers an increase in mitochondrial ROS, but there was no change in either mitochondrial membrane potential or the mitochondrial DNA copy number in mKSCs. The VPA treatment increased the mitochondrial complex III but decreased complex V significantly compared to the DMSO treatment as a control. The inflammatory marker (IL-6) and the expression of the apoptosis markers (Caspase 3) and were increased by VPA. In particular, the expression of the podocyte injury markers (CD2AP) was increased significantly. In conclusion, VPA exposure has adverse effects on mouse kidney stem cells.

Risk factors for and characteristics of community‐ and hospital‐acquired drug‐induced acute kidney injuries

Drugs constitute one of the leading causes of acute kidney injuries (AKIs) and can appear in community (CA‐AKI) or hospital (HA‐AKI) population. The objectives of the present study of a cohort of hospitalized patients with AKI were to describe the characteristics of drug‐induced AKIs and the patients' short‐term outcomes and assess risk factors for drug‐induced AKIs overall, CA‐AKIs, and HA‐AKIs. Based on a cohort of 1557 hospitalized patients suffering from AKIs based on PMSI extraction and chart review (IRA‐PMSI), drug‐induced AKIs were identified by applying the Naranjo adverse drug reaction (ADR) probability scale. Multivariate logistic regression was used to identify factors associated with CA‐AKIs and/or HA‐AKIs. When considering the 1557 patients who experienced an AKI, 445 (28.6%) of the injuries were drug‐induced (180 CA‐AKIs (40.4%) and 265 HA‐AKIs (59.6%)). Antibiotics, diuretics, and contrast agents were significantly more likely to be involved in HA‐AKIs, whereas antineoplastic, lipid‐lowering drugs, antidiabetics, and immunosuppressive were significantly more likely to be involved in CA‐AKIs. Female sex (odds ratio [OR] [95%CI] = 1.3 [1.04–1.67]), chronic kidney disease (CKD) (OR = 1.8 [1.40–2.67]), and a history of ADRs of any type (OR = 1.3 [1.05–1.73]) were significant risk factors for drug‐induced AKIs. CKD was a risk factor for both CA‐AKI and HA‐AKI. In view of the long‐term impact of AKI on the kidneys and the differences between our CA‐AKI and HA‐AKI subgroups, our present results are interesting for optimizing treatments, limiting the occurrence of CA‐ and HA‐AKIs and (ultimately) reducing healthcare costs.

Urine Microscopy Score and Neutrophil Lymphocyte Ratio at Presentation are Good Biomarkers of Acute Kidney Injury in Patients with Upper Urinary Tract Infection when Assessed in Correlation with Virulence Factors of Escherichia coli and Blood Group Secretor Status

Acute kidney injury (AKI) is a leading cause of morbidity in urinary tract infection (UTI). We aimed to identify simple biomarkers and bacterial virulence factors associated with AKI in a setting of upper UTI due to uropathogenic Escherichia coli (UPEC). We designed a cross-sectional study to analyse biomarkers of AKI in upper UTI patients. A total of 2758 patients presenting to a tertiary care center with symptoms of upper UTI were assessed for the presence of diabetes mellitus, AKI, blood group non-secretors, urine microscopy and hemogram. 300 patients with UPEC in bacterial culture were studied for bacterial virulence factors by phenotypic and genotypic methods and the patients were followed up for a minimum period of two weeks. Patients with diabetes mellitus, non-secretors, Urine microscopy (UM) score > 2 and higher (> 3.9) neutrophil-lymphocyte ratio (NLR) at initial presentation, were found to be significantly associated with AKI at presentation and predicted AKI at 7th and 14th day follow up. They were also significantly associated with need and increased duration of hospitalization. There was no association of virulence factors of UPEC with diabetes mellitus, AKI or need for hospitalization. However, virulence factors had a significant association (p<0.001)with non-secretors. UM score and NLR are simple tools to identify AKI at presentation and predict AKI during follow-up and the need for hospitalization. Patients with diabetes mellitus and non-secretors are also at higher risk of AKI. Non-secretors are significantly associated with both phenotypic and genotypic expression of virulence factors of UPEC.

Duration of Tenofovir Use and Diabetes Mellitus Predict Microalbuminuria among Well-controlled Human Immunodeficiency Virus-infected Patients Attending a Tertiary Clinic in Gaborone, Botswana

The study aimed to determine the prevalence and associated factors of microalbuminuria among patients infected with human immunodeficiency virus (HIV). A cross-sectional study was conducted at the Infectious Disease Control Center of Princess Marina Hospital, a Tertiary Clinic in Gaborone, Botswana. The risk factors of microalbuminuria were determined by comparing the sociodemographic and clinical characteristics of patients with the presence of microalbuminuria or normoalbuminuria. In total, 297 randomly selected HIV-infected patients were included in the analysis. The mean age of the study participants was 48.6 years, with the majority of patients (60.9%) being females. The study participants were largely well-controlled both immunologically and virologically, with 283/297 (95.3%) and 280/297 (94.3%), having CD4 counts of more than 200 cells/mm3 and undetected viral load (<400 copies/mL), respectively. The prevalence of microalbuminuria was found to be 46.5%. Microalbuminuria was associated with the duration of exposure to a regimen containing tenofovir [P <0.001, odds ratio = 1.137, 95% confidence interval (CI) = 1.073-1.205] and a history of diabetes mellitus (P = 0.044, odds ratio = 9.260, 95% CI = 1.058-81.06). Sociodemographic characteristics and other clinical factors were not associated with microalbuminuria. There is a need to carry out prospective studies among HIV- infected patients with microalbuminuria to determine the short- and long-term cardiovascular morbidity and mortality outcomes.

Nephrotoxicity in cancer treatment: An update

It has been estimated that nearly 80% of anticancer drug-treated patients receive potentially nephrotoxic drugs, while the kidneys play a central role in the excretion of anticancer drugs. Nephrotoxicity has long been a serious complication that hampers the effectiveness of cancer treatment and continues to influence both mortality and length of hospitalization among cancer patients exposed to either conventional cytotoxic agents or targeted therapies. Kidney injury arising from anticancer drugs tends to be associated with preexisting comorbidities, advanced cancer stage, and the use of concomitant non-chemotherapeutic nephrotoxic drugs. Despite the prevalence and impact of kidney injury on therapeutic outcomes, the field is sorely lacking in an understanding of the mechanisms driving cancer drug-induced renal pathophysiology, resulting in quite limited and largely ineffective management of anticancer drug-induced nephrotoxicity. Consequently, there is a clear imperative for understanding the basis for nephrotoxic manifestations of anticancer agents for the successful management of kidney injury by these drugs. This article provides an overview of current preclinical research on the nephrotoxicity of cancer treatments and highlights prospective approaches to mitigate cancer therapy-related renal toxicity.

Kidney Microcirculation as a Target for Innovative Therapies in AKI

Acute kidney injury (AKI) is a serious multifactorial conditions accompanied by the loss of function and damage. The renal microcirculation plays a crucial role in maintaining the kidney’s functional and structural integrity for oxygen and nutrient supply and waste product removal. However, alterations in microcirculation and oxygenation due to renal perfusion defects, hypoxia, renal tubular, and endothelial damage can result in AKI and the loss of renal function regardless of systemic hemodynamic changes. The unique structural organization of the renal microvasculature and the presence of autoregulation make it difficult to understand the mechanisms and the occurrence of AKI following disorders such as septic, hemorrhagic, or cardiogenic shock; ischemia/reperfusion; chronic heart failure; cardiorenal syndrome; and hemodilution. In this review, we describe the organization of microcirculation, autoregulation, and pathophysiological alterations leading to AKI. We then suggest innovative therapies focused on the protection of the renal microcirculation and oxygenation to prevent AKI.

Nephrotoxicity of Immune Checkpoint Inhibitors: A Disproportionality Analysis from 2013 to 2020

Nephrotoxicity occasionally occurs during treatment with immune checkpoint inhibitors (ICIs). Few related studies compare the differences between these drugs. This study aimed to systematically characterize nephrotoxicity after ICI initiation. Data were extracted from the US FDA Adverse Event Reporting System (FAERS) database. Disproportionality analysis, including information components (ICs) and reporting odds ratios (RORs), was performed to determine the potential renal toxicity of ICIs. A total of 7,204 reports of renal adverse events (AEs) were identified in the FAERS database. Renal AEs were most commonly reported for nivolumab (46.84%). Strong signals were detected in male patients combined with ICIs. In the clinical application of ICIs, attention should be paid to patients, especially male patients, with acute kidney injury, nephritis, autoimmune nephritis and other nephrotoxic AEs. The use of ICIs is likely to aggravate their condition.

Protective effects of natural products against drug-induced nephrotoxicity: A review in recent years

Drug-induced nephrotoxicity (DIN) is a major cause of kidney damage and is associated with high mortality and morbidity, which limits the clinical use of certain therapeutic or diagnostic agents, such as antineoplastic drugs, antibiotics, immunosuppressive agents, non-steroidal anti-inflammatory drugs (NSAIDs), and contrast agents. However, in recent years, a number of studies have shown that many natural products (NPs), including phytochemicals, various plants extracts, herbal formulas, and NPs derived from animals, confer protective effects against DIN through multi-targeting therapeutic mechanisms, such as inhibition of oxidative stress, inflammation, apoptosis, fibrosis, and necroptosis, regulation of autophagy, maintenance of cell polarity, etc., by regulating multiple signaling pathways and novel molecular targets. In this review, we summarize and discuss the protective effects and mechanisms underlying the action of NPs against DIN found in recent years, which will contribute to the development of promising renal protective agents.

Drug-induced acute kidney injury: diverse mechanisms of tubular injury

PURPOSE OF REVIEW

Medications are a relatively common cause of acute kidney injury (AKI), especially in hospitalized patients who are exposed to numerous agents. Drug-related acute tubular/tubulointerstitial injury is the most common cause of AKI associated with these agents. Toxic effects of drugs and their renal handling often lead to various forms of AKI.

RECENT FINDINGS

The inherent nephrotoxicity of drugs and their transport and metabolism by the kidneys play an important role in the occurrence of acute tubular injury. Apical transport of the aminoglycosides by endocytosis and apical pinocytosis of filtered hydroxyethyl starch into cells lead to acute tubular dysfunction. Transport of tenofovir and cisplatin by organic anion and cation transporters in the basolateral surface of the proximal tubule, respectively, are associated with intracellular drug accumulation and injury. Intratubular deposition of drug crystals with associated AKI occurs with several drugs, in particular the anticancer agent methotrexate. A potentially new mechanism of drug-induced AKI was described with vancomycin - acute vancomycin-related cast nephropathy. Immune-mediated acute tubulointerstitial injury is another cause of drug-induced AKI, as seen with immune checkpoint inhibitors.

SUMMARY

Drugs lead to AKI through mechanisms that involve their inherent toxicity as well as their transport and handling by the kidneys.

Design, Synthesis, and Renal Targeting of Methylprednisolone-Lysozyme

Methylprednisolone (MP) is often used in the treatment of various kidney diseases, but overcoming the systemic side effects caused by its nonspecific distribution in the body is a challenge. This article reports the design, synthesis, and renal targeting of methylprednisolone–lysozyme (MPS–LZM). This conjugate was obtained by covalently linking MP with the renal targeting carrier LZM through a linker containing an ester bond, which could utilize the renal targeting of LZM to deliver MP to renal proximal tubular epithelial cells and effectively release MP. The reaction conditions for the preparation of the conjugate were mild, and the quality was controllable. The number of drug payloads per LZM was 1.1. Cell-level studies have demonstrated the safety and endocytosis of the conjugate. Further pharmacokinetic experiments confirmed that, compared with that of free MP, the conjugate increased the renal exposure (AUC_0–t) of active MP from 17.59 to 242.18 h*ng/mL, and the targeting efficiency improved by approximately 14 times. Tissue and organ imaging further revealed that the conjugate could reach the kidneys quickly, and fluorescence could be detected in the kidneys for up to 12 h. This study preliminarily validates the feasibility of a renal targeting design strategy for MPS–LZM, which is expected to provide a new option for improving kidney-specific distribution of glucocorticoids.

Kidney-based in vitro models for drug-induced toxicity testing

The kidney is frequently involved in adverse effects caused by exposure to foreign compounds, including drugs. An early prediction of those effects is crucial for allowing novel, safe drugs entering the market. Yet, in current pharmacotherapy, drug-induced nephrotoxicity accounts for up to 25% of the reported serious adverse effects, of which one-third is attributed to antimicrobials use. Adverse drug effects can be due to direct toxicity, for instance as a result of kidney-specific determinants, or indirectly by, e.g., vascular effects or crystals deposition. Currently used in vitro assays do not adequately predict in vivo observed effects, predominantly due to an inadequate preservation of the organs' microenvironment in the models applied. The kidney is highly complex, composed of a filter unit and a tubular segment, together containing over 20 different cell types. The tubular epithelium is highly polarized, and the maintenance of this polarity is critical for optimal functioning and response to environmental signals. Cell polarity is dependent on communication between cells, which includes paracrine and autocrine signals, as well as biomechanic and chemotactic processes. These processes all influence kidney cell proliferation, migration, and differentiation. For drug disposition studies, this microenvironment is essential for prediction of toxic responses. This review provides an overview of drug-induced injuries to the kidney, details on relevant and translational biomarkers, and advances in 3D cultures of human renal cells, including organoids and kidney-on-a-chip platforms.

Efficacy of curcumin on prevention of drug-induced nephrotoxicity: A review of animal studies

Drug-induced nephrotoxicity is a frequent serious adverse effect, contributing to morbidity and increased healthcare utilization. Prevention or reversal is key. Curcumin has useful biological features that include antioxidant, anti-inflammatory, and anticancer properties. This review covers aspects of curcumin in relation to prevention of drug-induced nephrotoxicity: dosage and schedule, effect on kidney biomarkers and histological changes, and mechanisms of curcumin's protective effects. Despite success in some animal models, human studies and clinical administration of curcumin for nephroprotection remains limited due to difficulty in achieving therapeutic levels following oral administration and in determining the optimal dosing schedule. Lack of sufficient evidence from animal studies, coupled with low systemic bioavailability, continues to limit the utilization of curcumin in addressing and controlling drug-induced nephrotoxicity. Therefore, human studies are required to fully assess and validate the therapeutic potential of curcumin.

Incidence, management, and outcomes of autoimmune nephropathies following alemtuzumab treatment in patients with multiple sclerosis

Background:

Autoimmune disorders including nephropathies have been reported more frequently in alemtuzumab-treated multiple sclerosis (MS) patients than in the general population.

Objective:

Describe instances of autoimmune nephropathy in alemtuzumab-treated MS patients.

Methods:

Cases were identified from safety monitoring within the alemtuzumab relapsing-remitting multiple sclerosis (RRMS) clinical development program (CDP) or post-marketing, or following off-label use.

Results:

As of 16 June 2017, 16 autoimmune nephropathies have occurred following alemtuzumab treatment for MS. The incidence of autoimmune nephropathies was 0.34% within the CDP (5/1485 patients). The five CDP cases (one of anti-glomerular basement membrane (anti-GBM) disease, two of membranous glomerulonephropathy, and two of serum anti-GBM antibody without typical anti-GBM disease) were identified early, responded to conventional therapy (where needed), and had favorable outcomes. Three of 11 cases outside the CDP occurred following off-label alemtuzumab use prior to approval for RRMS and were all anti-GBM disease. Diagnosis was delayed in one of these three cases and another did not receive appropriate treatment; all three cases resulted in end-stage renal failure. All anti-GBM disease cases with documented urinalysis demonstrated prior microscopic hematuria.

Conclusion:

Close monitoring of alemtuzumab-treated MS patients facilitates diagnosis and treatment early in the nephropathy course when preservation of renal function is more likely.

Pathologic Perspectives on Acute Tubular Injury Assessment in the Kidney Biopsy

The molecular mechanisms in acute tubular injury (ATI) are complex and enigmatic. Moreover, we currently lack validated tissue injury markers that can be integrated into the kidney biopsy analysis to guide nephrologists in their patient's management of AKI. Although recognizing the ATI lesion by light microscopy is fairly straightforward, the staging of tubular lesions in the context of clinical time course and etiologic mechanism currently is not adapted to the renal pathology practice. To the clinician, the exact time point when an ischemic or toxic injury has occurred often is not known and cannot be discerned from the review of the biopsy sample. Moreover, the assessment of the different types of organized necrosis as the underlying cell death mechanism, which can be targeted using specific inhibitors, has not yet reached clinical practice. The renal pathology laboratory is uniquely qualified to assess the time course and etiology of ATI using established analytic techniques, such as immunohistochemistry and electron microscopy. Recent advances in the understanding of pathophysiological mechanisms of ATI and the important role that certain types of tubular cell organelles play in different stages of the ATI lesions may allow differentiation of early versus late ATI. Furthermore, the determination of respective cell injury pathways may help to differentiate ischemic versus toxic etiology in a reliable fashion. In the future, such a kidney biopsy-based classification system of ATI could guide the nephrologist's management of patients in regard to treatment modality and drug choice.

Pharmacology behind Common Drug Nephrotoxicities

Patients are exposed to numerous prescribed and over-the-counter medications. Unfortunately, drugs remain a relatively common cause of acute and chronic kidney injury. A combination of factors including the innate nephrotoxicity of drugs, underlying patient characteristics that increase their risk for kidney injury, and the metabolism and pathway of excretion by the kidneys of the various agents administered enhance risk for drug-induced nephrotoxicity. This paper will review these clinically relevant aspects of drug-induced nephrotoxicity for the clinical nephrologist.

Alda-1, an aldehyde dehydrogenase-2 agonist, causes deterioration in renal functions following ischemia-reperfusion injury due to crystalline nephropathy

Renal ischemia-reperfusion injury (IRI) induces the production of aldehydes which are detoxified by aldehyde dehydrogenases (ALDHs). Alda-1 is a selective ALDH2 agonist and its protective effect was demonstrated in several conditions. The effect of Alda-1 on the kidney or on renal IRI was not investigated. We investigated the effect of Alda-1 on the renal dysfunction following IRI. Wistar rats underwent left IRI for 40 min. Group-Alda (n = 11) received Alda-1 starting 24 h before IRI and continued for 7 days thereafter when renal functions were measured. Group-Vx (n = 11) underwent similar protocol but received the dissolvent. Alda-1 did not affect renal blood flow or glomerular filtration rate in the left ischemic kidney in Group-Alda compared to Group-Vx (3.05 ± 0.50 vs. 3.53 ± 0.70, and 0.40 ± 0.06 vs. 0.51 ± 0.08, respectively, p > .05 for both). However, left renal fractional sodium excretion was higher in Group-Alda (2.80 ± 0.43 vs. 1.37 ± 0.36, p = .02). Alda-1 also adversely affected the gene expressions of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin (217 ± 38 vs. 99 ± 13 and 49 ± 13 vs. 20 ± 5, respectively, p < .05 for both) and the alterations in tumor necrosis factor-α, transforming growth factor-β1, plasminogen activator inhibitor-1, fibronectin 1 and p53 (4.4 ± 0.9 vs. 2.1 ± 0.3, 1.5 ± 0.1 vs. 1.1 ± 0.1, 30.0 ± 2.7 vs. 11.7 ± 2.3, 3.6 ± 0.4 vs. 2.1 ± 0.2 and 1.3 ± 0.1 vs. 0.9 ± 0.07, respectively, p ≤ .05 for all). This was associated with intratubular crystal deposition suggestive of crystalline nephropathy. Alda-1 exacerbated the IRI-induced renal tubular dysfunction and alterations in markers of acute kidney injury, biomarkers of inflammation, fibrosis and apoptosis and this was associated with intratubular crystal deposition suggestive of crystalline nephropathy.

Effect of tramadol addiction alone and its co-abuse with cannabis on urinary excretion of Copper, Zinc, and Calcium among Egyptian addicts

BACKGROUND

The use of illicit drugs has become a worldwide health problem. Substances with the potential to be abused may have direct or indirect effects on physiologic mechanisms that lead to organ system dysfunction and diseases.

OBJECTIVE

The present study aims to investigate the structural and reabsorption integrity of the nephron among Egyptian addicts of tramadol alone and coabused with cannabis.

METHODS

Sixty-five males were included in the study, they were classified into control group (G1=19), tramadol addicts group (G2=18), and tramadol coabused with cannabis addicts group (G3=28). Parameters investigated for structural integrity were urinary levels ofleucineaminopeptidase and N-acetyl-β-D-glucosaminidase, and urinary parameters for reabsorption integrity were levels of copper and zinc as well as calcium, also urinary creatinine was measured. In addition, urinary levels of tramadol and tetrahydrocannabinol were estimated.

RESULTS

Among the two addicted groups, all measured parameters were not significantly different in comparison with the control group except for urinary calcium excretion which was found to be significantly increased among the two addicted groups.

CONCLUSION

Both tramadol addiction alone or coabused with cannabis causes increased urinary excretion of calcium, indicating reabsorption dysfunction of calcium without affecting structural integrity along the nephron.

Post-contrast acute kidney injury. Part 2: risk stratification, role of hydration and other prophylactic measures, patients taking metformin and chronic dialysis patients : Recommendations for updated ESUR Contrast Medium Safety Committee guidelines

OBJECTIVES

The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 2011 guidelines on the prevention of post-contrast acute kidney injury (PC-AKI). The results of the literature review and the recommendations based on it, which were used to prepare the new guidelines, are presented in two papers. AREAS COVERED IN PART 2: Topics reviewed include stratification of PC-AKI risk, the need to withdraw nephrotoxic medication, PC-AKI prophylaxis with hydration or drugs, the use of metformin in diabetic patients receiving contrast medium and the need to alter dialysis schedules in patients receiving contrast medium.

KEY POINTS

• In CKD, hydration reduces the PC-AKI risk • Intravenous normal saline and intravenous sodium bicarbonate provide equally effective prophylaxis • No drugs have been consistently shown to reduce the risk of PC-AKI • Stop metformin from the time of contrast medium administration if eGFR < 30 ml/min/1.73 m 2 • Dialysis schedules need not change when intravascular contrast medium is given.

Management of adverse renal events related to alemtuzumab treatment in multiple sclerosis: a Belgian consensus

Alemtuzumab is a humanized monoclonal antibody indicated for the treatment of adult patients with relapsing–remitting multiple sclerosis with active disease. Multiple sclerosis (MS) patients treated with alemtuzumab are at increased risk for autoimmune adverse events (thyroid disorders, immune thrombocytopenia, and renal disease). The use of alemtuzumab has been associated with the development of renal immune-mediated adverse events in 0.3% of patients in clinical trials in MS, which generally occurred within 39 months of the last administration. Both anti-GBM disease and membranous nephropathy have been associated with the use of alemtuzumab. Early detection is necessary to allow for early diagnosis and prevent adverse renal and patient outcomes. Through the implementation of the risk minimization measures, patients can be diagnosed, and treated if needed, early allowing for generally favorable outcomes. This important goal can be reached through health care professional and patient education, careful analysis of the monthly lab tests, and close collaboration between the patient, neurologist, and the nephrologist. This article presents the consensus of Belgian MS specialists and nephrologists on the practicalities of diagnosis, management, and treatment of alemtuzumab-associated renal adverse events based on good clinical practice.

Drug-Induced Kidney Injury in the Elderly

The incidence of acute kidney injury in the elderly has grown over the past decade. One of the primary drivers is drug-induced nephrotoxicity, which is the result of a combination of the unique susceptibilities to kidney injury and the increased use of medications in the elderly population. Specific drug classes are associated with increased rates of kidney injury including agents that block the renin angiotensin system, antimicrobials, and chemotherapeutic agents. Mechanistically, injury may be due to hemodynamic effects, tubular or glomerular toxicity, and interstitial nephritis. Early recognition of nephrotoxicity is critical, as are preventative steps when applicable. Unfortunately, treatment for established drug-induced kidney injury is limited and supportive care is required. Limiting exposure to nephrotoxic drugs is critical in decreasing the incidence of acute kidney injury in the elderly patient.

Dramatic Increase of Amoxicillin-Induced Crystal Nephropathy Found in a Cohort Study of French Pharmacovigilance Centers

An increase in amoxicillin-induced crystal nephropathy (AICN) incidence has been recently suggested. The aims of this study were to investigate the trend of AICN incidence through Paris' regional centers of pharmacovigilance (Paris RCPVs) and better describe this rare adverse drug reaction. Forty-five AICN cases were identified between 1985 and 2016. All cases, except one, were reported since 2010. Amoxicillin (AMX) was administered intravenously (65 [interquartile range {IQR}, 43 to 110] mg/kg of body weight/day) in all patients, either for treating infection (n = 15) or as surgical prophylaxis (n = 30). Delay between AMX administration and AICN onset was 1 (IQR, 1 to 3) day; 30, 4, and 11 patients developed KDIGO stage 1, 2, and 3 acute kidney injury, respectively. Delay between AICN onset and kidney function recovery was 4 (IQR, 2 to 6) days. Precipitating factors were identified in only one-third of cases. Twelve patients required intensive care unit admission, and 8 needed renal replacement therapy. Neither chronic kidney disease nor death was observed. We confirmed the recent and dramatic increase of AICN in the Paris RCPVs since 2010. The absence of precipitating factors in the majority of cases and the onset of AICN in apparent routine indications, such as surgical prophylaxis, are alarming and justify a high vigilance from all AMX prescribers.

Alteration of renal excretion pathways in gentamicin-induced renal injury in rats

The kidney plays a major part in the elimination of many drugs and their metabolites, and drug-induced kidney injury commonly alters either glomerular filtration or tubular transport, or both. However, the renal excretion pathway of drugs has not been fully elucidated at different stages of renal injury. This study aimed to evaluate the alteration of renal excretion pathways in gentamicin (GEN)-induced renal injury in rats. Results showed that serum cystatin C, creatinine and urea nitrogen levels were greatly increased by the exposure of GEN (100 mg kg^-1 ), and creatinine concentration was increased by 39.7% by GEN (50 mg kg^-1 ). GEN dose-dependently upregulated the protein expression of rOCT1, downregulated rOCT2 and rOAT1, but not affected rOAT2. Efflux transporters, rMRP2, rMRP4 and rBCRP expressions were significantly increased by GEN(100), and the rMATE1 level was markedly increased by GEN(50) but decreased by GEN(100). GEN(50) did not alter the urinary excretion of inulin, but increased metformin and furosemide excretion. However, GEN(100) resulted in a significant decrease of the urinary excretion of inulin, metformin and p-aminohippurate. In addition, urinary metformin excretions in vivo were significantly decreased by GEN(100), but slightly increased by GEN(50). These results suggested that GEN(50) resulted in the induction of rOCTs-rMATE1 and rOAT3-rMRPs pathway, but not changed the glomerular filtration rate, and GEN(100)-induced acute kidney injury caused the downregulated function of glomerular filtration -rOCTs-rMATE1 and -rOAT1-rMRPs pathway.

Glomerular filtration drug injury: In vitro evaluation of functional and morphological podocyte perturbations

The kidney is an organ that plays a major role in the excretion of numerous compounds such as drugs and chemicals. However, a great number of pharmacological molecules are nephrotoxic, affecting the efficiency of the treatment and increasing morbidity or mortality. Focusing on glomerular filtration, we propose in this study a simple and reproducible in vitro human model that is able to bring to light a functional podocyte injury, correlated with morphologic/phenotypic changes after drug exposure. This model was used for the evaluation of paracellular permeability of FITC-dextran molecules as well as FITC-BSA after different treatments. Puromycin aminonucleoside and adriamycin, compounds known to induce proteinuria in vivo and that serve here as positive nephrotoxic drug controls, were able to induce an important increase in fluorescent probe passage through the cell monolayer. Different molecules were then evaluated for their potential effect on podocyte filtration. Our results demonstrated that a drug effect could be time dependent, stable or scalable and relatively specific. Immunofluorescence studies indicated that these functional perturbations were due to cytoskeletal perturbations, monolayer disassembly or could be correlated with a decrease in nephrin expression and/or ZO-1 relocation. Taken together, our results demonstrated that this in vitro human model represents an interesting tool for the screening of the renal toxicity of drugs.

Adverse safety events in patients with Chronic Kidney Disease (CKD)

INTRODUCTION

Chronic kidney disease (CKD) confers a higher risk of adverse safety events as a result of many factors including medication dosing errors and use of nephrotoxic drugs, which can cause kidney injury and renal function decline. CKD patients may also have comorbidities such as hypertension and diabetes for which they require more frequent care from different providers, and for which standard, but countervailing treatments, may put them at risk for adverse safety events. Areas covered: In addition to the well-known agents such as iodinated radiocontrast, antimicrobials, diuretics and angiotensin converting enzyme (ACE) inhibitors which can directly affect renal function, safety considerations in the treatment of common CKD complications such as anemia, diabetes, analgesia and thrombosis will also be discussed. Expert opinion: Better outcomes in CKD may be achieved by alerting care providers to the special care needs of kidney patients and encouraging patients to self-manage their disease with the decision support of multidisciplinary patient care teams.

Dialyzability of Oxycodone and Its Metabolites in Chronic Noncancer Pain Patients with End-Stage Renal Disease

OBJECTIVES

Opioids are the preferred analgesic drugs to treat severe chronic pain conditions among dialysis patients; however, knowledge about their dialyzability features is limited. Oxycodone is increasingly used for the treatment of chronic pain conditions as oral controlled release (CR) tablets; however, evidence about this drug and its metabolites' dialyzability is lacking.

METHODS

We assessed, during 4-hour dialysis sessions, the effect of standard hemodialysis (HD) and online hemodiafiltration (HDF) methods on the plasma concentration of oxycodone and its metabolites in n = 20 chronic pain patients with end-stage renal disease who were stably treated with oral CR oxycodone. Chromatographic techniques were used to evaluate the studied compounds' plasma concentrations at three different time points during dialysis.

RESULTS

Mean plasma concentrations of oxycodone and noroxycodone in the sample showed an overall reduction trend over time, but it was less enhanced for noroxycodone. Mean reduction in oxycodone and noroxycodone arterial concentrations was significant and higher with HDF (54% and 27%, respectively) than with HD (22% and 17%, respectively). Analysis of the regression of these compounds' clearance on their increasing arterial concentration showed a more stable and linear clearance prediction with HDF (roughly 85 mL/min); with HD, for increasing arterial concentration, clearance of oxycodone decreased while noroxycodone clearance increased.

DISCUSSION

While no oxymorphone or noroxymorphone metabolites were detected, limited dialyzability of oxycodone and noroxycodone was documented along with insignificant postdialysis pain increment. This evidence will contribute toward considerations as to the safety of the use of oxycodone in dialysis patients in the future.

THE PURVIEW OF PHYTOTHERAPY IN THE MANAGEMENT OF KIDNEY DISORDERS: A SYSTEMATIC REVIEW ON NIGERIA AND SOUTH AFRICA

BACKGROUND

The kidney is tasked with a number of metabolic functions in the body. In its role as a detoxifier and primary eliminator of xenobiotics, it becomes vulnerable to developing injuries. Currently, over 1 million people in the world are living on renal replacement therapies (RRTs). The case in sub-Sahara African countries like Nigeria and South Africa is not any better than the global trend.

MATERIALS AND METHODS

A systematic review of medicinal plants used in the treatment of kidney disorders was conducted. Information were gathered from published scientific journals, books, reports from national, regional and international institutions, conference proceedings and other high profile intellectual resources. MeSH words like 'prevalence of kidney disorders in Africa', 'renal replacement therapy', 'nephrotoxins or nephrotoxicants', 'nephroprotective plants', 'nephroprotective plants in Nigeria or South Africa' and 'nephroprotective phytocompounds' were used to retrieve information from online databases (Google, Pubmed, MEDLINE, Science Direct, Scopus and SID).

RESULTS

Interestingly, our findings revealed that phytotherapy has emerged and is being employed to protect renal functions and delay progression of renal pathological conditions into end episodes where the last resort is RRT. In fact, in recent times, Phytotherapists are not only interested in developing relatively safe, more affordable, easily accessible and potent nephroprotective formulations but also increasing awareness on the prevalence of the disease and educating the populace on the probable preventive measures. More importantly, efforts at scientifically elucidating the pharmacological efficacy of the identified nephroprotective plants yet to be validated must be intensified through informed expert opinions. Till date, there is paucity of information on the concept of nephroprotection in most developing countries where kidney disorder is a major threat. Although, the concept is just emerging in South Africa, evidences have given credence to its application in complementary and alternative system of medicine in Nigeria.

CONCLUSION

This review, therefore, reawaken researchers' consciousness in the continuous search for auspicious nephroprotective plants that could potentially be excellent candidates in developing new lead drugs to manage and treat renal disorders.

Drug-induced renal damage in preterm neonates: state of the art and methods for early detection

Only a small fraction of drugs widely used in neonatal intensive care units (NICU) are specifically authorized for this population. Even if unlicensed or off-label use is necessary, it is associated with increased adverse drug reactions, which must be carefully weighed against expected benefits. In particular, renal damage is frequent among preterm babies, and is considered a predisposing factor for the development of chronic kidney disease in adulthood. Apart from specific conditions affecting premature neonates (e.g. respiratory distress syndrome, perinatal asphyxia), drugs play an important role in impairing renal function because of well-known nephrotoxicity and/or interaction with renal developmental factors. From a review of the available studies on drug use in NICU patients, we identified and described the most commonly administered drugs that are correlated to renal damage. Early detection of kidney injury is becoming an essential aspects for clinicians because of the limited number of biomarkers applicable in the neonatal population. Postnatal changes of biochemical processes that influence pharmacokinetic and pharmacodynamic aspects need to be further investigated in order to better understand the mechanisms of drug toxicity in this population. The most promising strategies for dose adjustment and therapeutic schemes are discussed. The purpose of this review was to describe current knowledge on drug use among premature babies and their implication in kidney injury development, as well as to highlight available strategies for early detection of renal damage.

Practical considerations to drug dosing in children with acute kidney injury

Medication dosing for children with acute kidney injury (AKI) needs to be individualized based on pharmacokinetic and pharmacodynamic principles of the prescribed drugswhenever possible to optimize therapeutic outcome and to minimize toxicity. The pediatric RIFLE criteria should be prospectively utilized to identify patients at highest risk of developing AKI. Serum creatinine and urine output along with volume status should be utilized to guide drug dosing when urinary biomarkers including kidney injury molecule 1, interleukin-18, or neutrophil gelatinase-associated lipocalin are not readily available. Because of the presence of a positive fluid balance in early stages of AKI, the dosing regimen for many drugs, especially antimicrobial agents, should be initiated at a larger loading dose based on the expected volume of distribution to achieve target serum concentrations.When possible, therapeutic drug monitoring should be utilized for those medications where serum drug concentrations can be obtained in a clinically relevant time frame. For these medications, close monitoring of serum drug concentrations is highly recommended. This review addresses drug-dosing strategies in pediatric patients with AKI including the roles of therapeutic drug monitoring and newer kidney injury biomarkers.

Drug-induced renal disorders

Drug-induced nephrotoxicity are more common among infants and young children and in certain clinical situations such as underlying renal dysfunction and cardiovascular disease. Drugs can cause acute renal injury, intrarenal obstruction, interstitial nephritis, nephrotic syndrome, and acid-base and fluid electrolytes disorders. Certain drugs can cause alteration in intraglomerular hemodynamics, inflammatory changes in renal tubular cells, leading to acute kidney injury (AKI), tubulointerstitial disease and renal scarring. Drug-induced nephrotoxicity tends to occur more frequently in patients with intravascular volume depletion, diabetes, congestive heart failure, chronic kidney disease, and sepsis. Therefore, early detection of drugs adverse effects is important to prevent progression to end-stage renal disease. Preventive measures requires knowledge of mechanisms of drug-induced nephrotoxicity, understanding patients and drug-related risk factors coupled with therapeutic intervention by correcting risk factors, assessing baseline renal function before initiation of therapy, adjusting the drug dosage and avoiding use of nephrotoxic drug combinations

Estimated glomerular filtration rate changes in patients with chronic myeloid leukemia treated with tyrosine kinase inhibitors

BACKGROUND

Chronic use of tyrosine kinase inhibitors (TKIs) may lead to previously unrecognized adverse events. This study evaluated the incidence of acute kidney injury (AKI) and chronic kidney disease (CKD) in chronic-phase (CP) chronic myeloid leukemia (CML) patients treated with imatinib, dasatinib, and nilotinib.

METHODS

Four hundred sixty-eight newly diagnosed CP CML patients treated with TKIs were analyzed. The molecular and cytogenetic response data, creatinine, and glomerular filtration rate (GFR) were followed from the start of therapy to the last follow-up (median, 52 months). GFR was estimated with the Modification of Diet in Renal Disease equation.

RESULTS

Nineteen patients (4%) had TKI-associated AKI. Imatinib was associated with a higher incidence of AKI in comparison with dasatinib and nilotinib (P = .014). Fifty-eight patients (14%) developed CKD while they were receiving a TKI; 49 of these patients (84%) did so while they were being treated with imatinib (P < .001). Besides imatinib, age, a history of hypertension, and diabetes mellitus were also associated with the development of CKD. In patients with no CKD at the baseline, imatinib was shown to reduce GFR over time. Interestingly, imatinib did not cause a significant decline in the GFRs of patients with a history of CKD. Imatinib, dasatinib, and nilotinib increased the mean GFR after 3 months of treatment, and nilotinib led with the most significant increase (P < .001). AKI or CKD had no significant impact on overall cytogenetic and molecular response rates or survival.

CONCLUSIONS

The administration of TKIs may be safe in the setting of CKD in CP CML patients, but close monitoring is still warranted.

Nonsteroidal anti-inflammatory drugs alter vasa recta diameter via pericytes

We have previously shown that vasa recta pericytes are known to dilate vasa recta capillaries in the presence of PGE2 and contract vasa recta capillaries when endogenous production of PGE2 is inhibited by the nonselective nonsteroidal anti-inflammatory drug (NSAID) indomethacin. In the present study, we used a live rat kidney slice model to build on these initial observations and provide novel data that demonstrate that nonselective, cyclooxygenase-1-selective, and cyclooxygenase -2-selective NSAIDs act via medullary pericytes to elicit a reduction of vasa recta diameter. Real-time images of in situ vasa recta were recorded, and vasa recta diameters at pericyte and nonpericyte sites were measured offline. PGE2 and epoprostenol (a prostacyclin analog) evoked dilation of vasa recta specifically at pericyte sites, and PGE2 significantly attenuated pericyte-mediated constriction of vasa recta evoked by both endothelin-1 and ANG II. NSAIDs (indomethacin > SC-560 > celecoxib > meloxicam) evoked significantly greater constriction of vasa recta capillaries at pericyte sites than at nonpericyte sites, and indomethacin significantly attenuated the pericyte-mediated vasodilation of vasa recta evoked by PGE2, epoprostenol, bradykinin, and S-nitroso-N-acetyl-l-penicillamine. Moreover, a reduction in PGE2 was measured using an enzyme immune assay after superfusion of kidney slices with indomethacin. In addition, immunohistochemical techniques were used to demonstrate the population of EP receptors in the medulla. Collectively, these data demonstrate that pericytes are sensitive to changes in PGE2 concentration and may serve as the primary mechanism underlying NSAID-associated renal injury and/or further compound-associated tubular damage.

Transcription profile of genes affected in response to pathological changes in drug-induced rat model of acute kidney injury

OBJECTIVE

The objective of the present study was to examine the changes in the expression profile of certain genes in rat model of gentamicin-induced acute kidney injury (AKI) and to see whether time period and routes of administration affect their expression levels.

METHODS

Rat AKI model was established with gentamicin injection using two different routes of administration and two different time periods. The models were evaluated through histopathological observations. Renal specific genes were selected on the basis of their role during kidney injury. These genes were analyzed through reverse transcriptase (RT) PCR.

RESULTS

Marked disorganization of normal structure of proximal and distal tubules was observed in all the gentamicin-treated groups. Many tubules showed loss of brush border and presence of intratubular protein casts. Changes in gene expression levels were observed for kidney injury molecule (KIM-1), osteopontin, bone morphogenic protein-7 (BMP-7), extracellular signal-regulated kinases (ERK), stem cell factor (SCF) and IL-7 receptor with different levels of significance in the renal injury groups studied depending on the time period and route of administration.

CONCLUSION

Gene expression seems to be dependent partly on the type of injury, route of administration and time period after induction of injury. An improved mechanistic understanding of gene regulation pathways in AKI may provide basis for potential therapeutic development.

Preclinical pharmacokinetic studies of 3-deazaneplanocin A, a potent epigenetic anticancer agent, and its human pharmacokinetic prediction using GastroPlus™

DZNep is a potential epigenetic drug, and exerts potent anti-proliferative and pro-apoptotic effects on broad-spectrum carcinomas via disruption of the EZH2 pathway. Antitumor studies on DZNep have been stuck in the preclinical phase because of the lack of information about its integral pharmacokinetic (PK) properties. To circumvent this problem, we extensively investigated the disposition characteristics of the DZNep in rats. By incorporating the disposition data across species into a whole-body physiologically based pharmacokinetic (PBPK) models using the GastroPlus(TM) software, we simulated human PK properties of DZNep and determined whether DZNep could be developed for human cancer therapy. Firstly, DZNep was found to cause nephrotoxicity in a dose-dependent manner in rats and its safe dose was determined to be 10mg/kg. DZNep showed a short plasma elimination half-life (1.1h) in rats, a low protein binding in plasma (18.5%), a low partitioning to erythrocyte (0.78), and a low intrinsic hepatic clearance in rats and humans. There was extensive tissue distribution and predominant renal excretion (80.3%). The simulated rat PBPK model of DZNep was well-verified with satisfactory coefficients of determination for all the tested tissues (R(2)>0.781). The simulated human PBPK model successfully identified that intravenous administration of DZNep at appropriate dosing regimen could be further developed for human non-small cell lung carcinoma treatments. The present findings provide valuable information regarding experimental or in silico PK characteristics of DZNep in rats and humans, which is helpful to guide future studies of DZNep in both preclinical and clinical phases.