Drug-induced renal failure: a focus on tubulointerstitial disease

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.

Poisoning-Induced Acute Kidney Injury: A Review

Acute kidney injury (AKI) is a debilitating, multi-etiological disease that is commonly seen in clinical practice and in the emergency department. In this review, we introduce the definition, symptoms, and causes of poisoning-related AKI; we also discuss its mechanisms, risk factors, and epidemiology, as well as elaborate on the relevant laboratory tests. Subsequently, we discuss the treatment strategies for toxin- and substance-related AKI caused by Glafenin, antimicrobial agents, lithium, contrast media, snake venom, herbicides, ethylene glycol, synthetic cannabinoids, cocaine, heroin, and amphetamines. Finally, for a comprehensive overview of poisoning-related AKI, we review the management, prevention, and outcomes of this condition.

The NLRP3 Inflammasome Is a Major Cause of Acute Renal Failure Induced by Polypeptide Antibiotics

Drug-induced acute renal failure (ARF) is a public health concern that hinders optimal drug therapy. However, pathological mechanisms of drug-induced ARF remain to be elucidated. Here, we show that a pathological process of drug-induced ARF is mediated by proinflammatory cross-talk between kidney tubular cells and macrophages. Both polymyxin B and colistin, polypeptide antibiotics, frequently cause ARF, stimulated the ERK and NF-κB pathways in kidney tubular cells, and thereby upregulated M-CSF and MCP-1, leading to infiltration of macrophages into the kidneys. Thereafter, the kidney-infiltrated macrophages were exposed to polypeptide antibiotics, which initiated activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome. Interestingly, blockade of the NLRP3 activation clearly ameliorated the pathology of ARF induced by polypeptide antibiotics, suggesting that a combination of the distinct cellular responses to polypeptide antibiotics in kidney tubular cells and macrophages plays a key role in the pathogenesis of colistin-induced ARF. Thus, our results provide a concrete example of how drugs initiate ARF, which may give insight into the underlying pathological process of drug-induced ARF.

A Review on the Role of Phytoconstituents Chrysin on the Protective Effect on Liver and Kidney

BACKGROUND

The chance of contracting significant diseases increases due to an unhealthy and contemporary lifestyle. Chrysin is a flavonoid of the flavone class in numerous plants, including Passiflora and Pelargonium. Chrysin has long been used to treat a variety of illnesses. Chrysin, an essential flavonoid, has many pharmacological actions, including anticancer, antiviral, anti-inflammatory, anti-arthritic, depressive, hypolipidemic, hepatoprotective, and nephroprotective activity.

PURPOSE

This explorative review was commenced to provide a holistic review of flavonoids confirming that Chrysin has a therapeutic potential on the liver and kidney and reduces the hepatotoxicity and nephrotoxicity induced by diverse toxicants, which can be helpful for the toxicologists, pharmacologists, and chemists to develop new safer pharmaceutical products with chrysin and other toxicants.

STUDY DESIGN

The most relevant studies that were well-explained and fit the chosen topic best were picked. The achieved information was analyzed to determine the outcome by screening sources by title, abstract, and whole work. Between themselves, the writers decided on the studies to be considered. The necessary details were systematically organized into titles and subtitles and compressively discussed.

METHOD

The information presented in this review is obtained using targeted searches on several online platforms, including Google Scholar, Scifinder, PubMed, Science Direct, ACS publications, and Wiley Online Library. The works were chosen based on the inclusion criteria agreed upon by all authors.

RESULTS

Chrysin is a promising bioactive flavonoid with significant health benefits, and its synthetic replacements are being utilized as pharmaceuticals to treat various diseases. Findings revealed that Chrysin exhibits hepatoprotective actions against several hepatotoxicants like 2,3,7,8 tetrachlorodibenzo- p-dioxin, carbon tetrachloride (CCl4), cisplatin, and others by lowering the levels of liver toxicity biomarkers and enhancing antioxidant levels. Additionally, chrysin has potential nephroprotective properties against various nephrotoxicants, like Cisplatin, Doxorubicin, Paracetamol, Gentamicin, Streptazosin, and others by dropping kidney toxicity marker levels, reducing oxidative stress, and improving the antioxidant level.

CONCLUSION

According to this revised study, chrysin is a promising phytoconstituent that can be utilized as an alternate treatment for various medications that cause hepatotoxicity and nephrotoxicity. With active chrysin, several dosage forms targeting the liver and kidneys can be formulated.

A Real-World Data Derived Pharmacovigilance Assessment on Drug-Induced Nephropathy: Implication on Gaps in Patient Care

This retrospective cross-sectional study aims to investigate the prevalence and seriousness of drug-induced nephrotoxicity and to identify clinical predictors intensifying the seriousness of nephrotoxicity. Adverse drug events (ADEs) reported to the Korean Adverse Event Reporting System Database (KAERS DB) from January 2012 to December 2021 were investigated. The association between the seriousness and the etiologic drug was estimated in reporting odds ratio (ROR) based on disproportionality analysis. Logistic regression was utilized to recognize predictors associated with serious nephrotoxicity. The majority of ADEs were reported in ages 30 to 59, and immunosuppressants were the most etiologic medications. ADEs involving antibiotics, including vancomycin (ROR 0.268; 95% CI 0.129-0.557), were less likely to be serious. More than 93% of cyclosporine-related ADEs were serious nephrotoxicity, whereas tacrolimus was less likely to report serious nephrotoxicity (ROR 0.356; 95% CI 0.187-0.680). The risk of serious nephrotoxicity was decreased with aging (ROR 0.955; 95% CI 0.940-0.972) while increased in women (OR 2.700; 95% CI 1.450-5.008). Polypharmacy was associated with increased risk of interstitial nephritis (OR 1.019; 95% CI 1.001-1.038). However, further studies investigating the impact of clinical practice on ADE incidences as well as clinical prognosis related to nephrotoxicity are obligated.

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.

[Basic nephropathology for pathologists-part 2 : Non-inflammatory lesions]

The evaluation of kidney biopsies for specific renal diseases or kidney transplant biopsies is mainly restricted to specialized centers. Lesions in nonneoplastic renal tissue in partial nephrectomies or nephrectomies due to renal tumors, especially noninflammatory, ischemic, vascular changes or diabetic nephropathy can be of greater prognostic significance than the tumor itself in patients with a localized tumor and good tumor-associated survival. In this part of basic nephropathology for pathologists, the most common noninflammatory lesions of the vascular, glomerular and tubulo-interstitial compartment are discussed.

Nephrotoxicity of iopamidol is associated with mitochondrial impairment in human cell and teleost models

Iopamidol is a nonionic, low-osmolar iodinated contrast agent used for angiography. Its clinical use is associated with renal dysfunction. Patients suffering from preexisting kidney disease have an increased risk of renal failure upon iopamidol administration. Studies in animals confirmed renal toxicity, but the involved mechanisms remain unclear. Therefore, the aim of the present study was to use human embryonic kidney cells (HEK293T) as a general cell model of mitochondrial damage, as well as, zebrafish larvae, and isolated proximal tubules of killifish to investigate factors promoting renal tubular toxicity of iopamidol with a focus on mitochondrial damage. Results from in vitro HEK293T cell-based assays indicate that iopamidol affects mitochondrial function Treatment with iopamidol induces ATP depletion, reduces the mitochondrial membrane potential, and elevates mitochondrial superoxide and reactive oxygen species accumulation. Similar results were obtained with gentamicin sulfate and cadmium chloride, two well-known model compounds associated with renal tubular toxicity. Confocal microscopy confirms changes in mitochondrial morphology, such as mitochondrial fission. Importantly, these results were confirmed in proximal renal tubular epithelial cells using ex vivo and in vivo teleost models. In conclusion, this study provides evidence for iopamidol-induced mitochondrial damage in proximal renal epithelial cells. Teleost models allow studying proximal tubular toxicity with translational relevance for humans.

Melatonin Treatment in Kidney Diseases

Melatonin is a neurohormone that is mainly secreted by the pineal gland. It coordinates the work of the superior biological clock and consequently affects many processes in the human body. Disorders of the waking and sleeping period result in nervous system imbalance and generate metabolic and endocrine derangements. The purpose of this review is to provide information regarding the potential benefits of melatonin use, particularly in kidney diseases. The impact on the cardiovascular system, diabetes, and homeostasis causes melatonin to be indirectly connected to kidney function and quality of life in people with chronic kidney disease. Moreover, there are numerous reports showing that melatonin plays a role as an antioxidant, free radical scavenger, and cytoprotective agent. This means that the supplementation of melatonin can be helpful in almost every type of kidney injury because inflammation, apoptosis, and oxidative stress occur, regardless of the mechanism. The administration of melatonin has a renoprotective effect and inhibits the progression of complications connected to renal failure. It is very important that exogenous melatonin supplementation is well tolerated and that the number of side effects caused by this type of treatment is low.

Flavonoids of Haloxylon salicornicum (Rimth) prevent cisplatin-induced acute kidney injury by modulating oxidative stress, inflammation, Nrf2, and SIRT1

Cisplatin (CIS) is an effective chemotherapeutic drug used for the treatment of many types of cancers, but its use is associated with adverse effects. Nephrotoxicity is a serious side effect of CIS and limits its therapeutic utility. Haloxylon salicornicum is a desert shrub used traditionally in the treatment of inflammatory disorders, but neither its flavonoid content nor its protective efficacy against CIS nephrotoxicity has been investigated. In this study, seven flavonoids were isolated from H. salicornicum methanolic extract (HSE) and showed in silico binding affinity with NF-κB, Keap1, and SIRT1. The protective effect of HSE against CIS nephrotoxicity was investigated. Rats received HSE (100, 200, and 400 mg/kg) for 14 days followed by a single injection of CIS. The drug increased Kim-1, BUN, and creatinine and caused multiple histopathological changes. CIS-administered rats showed an increase in renal ROS, MDA, NO, TNF-α, IL-1β, and NF-κB p65. HSE prevented tissue injury, and diminished ROS, NF-κB, and inflammatory mediators. HSE enhanced antioxidants and Bcl-2 and downregulated pro-apoptosis markers. These effects were associated with downregulation of Keap1 and microRNA-34a, and upregulation of SIRT1 and Nrf2/HO-1 signaling. In conclusion, H. salicornicum is rich in flavonoids, and its extract prevented oxidative stress, inflammation, and kidney injury, and modulated Nrf2/HO-1 and SIRT1 signaling in CIS-treated rats.

Twenty-Three-Year Trends in the Use of Potentially Nephrotoxic Drugs in Denmark

Background

The occurrence of acute and chronic kidney diseases has been rising in the last decades. Although drug use is a common risk factor for impaired kidney function, changes in utilization of potential nephrotoxic drugs have received little attention.

Purpose

To describe temporal trends in the utilization of potentially nephrotoxic drugs in Denmark between 1999 and 2021.

Methods

Specific drugs known or suspected to be nephrotoxic were identified in the literature. Data on the sold defined daily doses (DDDs) of potentially nephrotoxic drugs between 1999 and 2021 were retrieved using the Danish Register of Medical Product Statistics. Trends in sales of DDDs per 1000 inhabitants per day were tabulated and illustrated graphically.

Results

From 1999 to 2021, the total sale of all selected drugs increased from 286 to 457 DDDs per 1000 inhabitants per day. The overall sale reached a preliminary peak in 2012 with 449 DDDs per 1000 inhabitants per day and remained relatively stable thereafter until reaching an all-time high in 2021 with 457 DDDs per 1000 inhabitants per day. Contributing with the majority in volume, sales of drugs inhibiting the renin-angiotensin-aldosterone system (RAAS) increased dramatically throughout the period. The same was observed for acetaminophen, methotrexate, tacrolimus, and iodinated contrast dye. In contrast, the sales of diuretics, acetylsalicylic acid, and ciclosporin decreased during the last decade of the study period.

Conclusion

From 1999-2021 considerable changes in sales of potentially nephrotoxic drugs were observed. In general, the sales increased, in volume predominated by RAAS inhibiting drugs. This increase in sales of potential nephrotoxins could contribute to an increasing occurrence of kidney diseases.

The Effect of Donor Rat Gender in Mitochondrial Transplantation Therapy of Cisplatin-Induced Toxicity on Rat Renal Proximal Tubular Cells

Background

Cisplatin-induced nephrotoxicity has been linked to a fundamental mechanism of mitochondrial dysfunction. A treatment called mitochondrial transplantation therapy can be used to replace damaged mitochondria with healthy mitochondria. Mitochondrial-related diseases may benefit from this approach.

Objectives

We investigated the effect of mitochondrial transplantation on cisplatin-induced nephrotoxicity using freshly isolated mitochondria obtained from renal proximal tubular cells (RPTCs).

Methods

Based on our previous findings, we hypothesized that direct exposure of healthy mitochondria to cisplatin-affected RPTCs might improve cytotoxicity markers and restore mitochondrial function. Therefore, the primary objective of this study was to determine whether newly isolated mitochondrial transplantation protected RPTCs from cisplatin-induced cytotoxicity. The supply of exogenous rat kidney mitochondria to cisplatin-affected RPTCs was also a goal of this study to investigate the possibility of gender differences. After the addition of cisplatin (100 µM), rat RPTCs (106 cells/mL) were suspended in Earle's solution (pH = 7.4) at 37°C for two hours. Freshly isolated mitochondria were extracted at 4°C and diluted in 100 and 200 µg/mL mitochondrial protein.

Results

Statistical analysis revealed that transplantation of healthy mitochondria decreased ROS level, mitochondrial membrane potential (MMP) collapse, MDA level, glutathione depletion, lysosomal membrane damage, and caspase-3 activity induced by cisplatin in rat RPTCs. In addition, our results demonstrated that transplantation of female rat kidney mitochondria has higher protective activity at reducing toxicity parameters than male mitochondria.

Conclusions

The findings reaffirmed that mitochondrial transplantation is a novel, potential, and promising therapeutic strategy for xenobiotic-induced nephrotoxicity.

Subphenotypes of acute kidney injury in children

PURPOSE OF REVIEW

The purpose of this review is to describe acute kidney injury (AKI) phenotypes in children.

RECENT FINDINGS

AKI is a heterogenous disease that imposes significant morbidity and mortality on critically ill and noncritically ill patients across the age spectrum. As our understanding of AKI and its association with outcomes has improved, it is becoming increasingly apparent that there are distinct AKI subphenotypes that vary by cause or associated conditions. We have also learned that severity, duration, and repeated episodes of AKI impact outcomes, and that integration of novel urinary biomarkers of tubular injury can also reveal unique subphenotypes of AKI that may not be otherwise readily apparent.

SUMMARY

Studies that further delineate these unique AKI subphenotypes are needed to better understand the impact of AKI in children. Further delineation of these phenotypes has both prognostic and therapeutic implications.

Modulation Effects of Eugenol on Nephrotoxicity Triggered by Silver Nanoparticles in Adult Rats

The use of silver nanoparticles (AgNPs) is expanding. This study evaluates the modulator effect of eugenol (Eug) on AgNP-induced nephrotoxicity in rats. Sixty male rats were separated into six groups: control, Eug, AgNPs low-dose, AgNPs high-dose, Eug + AgNPs low-dose, and Eug + AgNPs high-dose. After 30 days, kidney function, antioxidative and proinflammatory status, histopathological, histomorphometrical, and immunohistochemical assessments were performed. AgNPs markedly induced oxidative stress in renal tissues, characterized by increased levels of blood urea nitrogen, creatinine, uric acid, kidney injury molecule-1, the total oxidant capacity, malondialdehyde, tumor necrosis factor-alpha (TNF-α), and interleukin-6, as well as decreased levels of the total antioxidant capacity, superoxide dismutase, catalase, reduced glutathione, and glutathione peroxidase. Moreover, the normal renal architecture was destroyed, and the thickness of the renal capsules, cortex, and medulla, alongside the diameter and quantity of the normal Malpighian corpuscles and the proximal and distal convoluted tubules were decreased. Immunoreactivity for P53, caspase-3, and TNF-α reactive proteins were significantly increased; however, Bcl-2 immunoreactivity was decreased. Eug reversed most biochemical, histological, histomorphometrical, and immunohistochemical changes in AgNP-treated animals. This study demonstrated that nephrotoxicity in AgNP-treated rats was mitigated by an Eug supplementation. Eug's antioxidant, antiapoptotic, and anti-inflammatory capabilities were the key in modulating AgNPs nephrotoxicity.

Infection in Living Donor Liver Transplantation Leads to Increased Risk of Adverse Renal Outcomes

(1) Background: Little is known about the subsequent renal function change following incident infectious diseases in living-donor liver transplant (LT) recipients. (2) Methods: We studied patients who underwent living-donor LT from January 2003 to January 2019 to evaluate the association of incident hospitalization with major infections or pneumonia with adverse renal outcomes, including a sustained 40% reduction in estimated glomerular filtration rate (eGFR) and renal composite outcome (a 40% decline in eGFR, end-stage renal disease, or death.). Multivariable-adjusted time-dependent Cox models with infection as a time-varying exposure were used to estimate hazard ratio (HR) with 95% confidence interval (CI) for study outcomes. (3) Results: We identified 435 patients (mean age 54.6 ± 8.4 years and 76.3% men), of whom 102 had hospitalization with major infections during follow-up; the most common cause of infection was pneumonia (38.2%). In multiple Cox models, hospitalization with a major infection was associated with an increased risk of eGFR decline > 40% (HR, 3.32; 95% CI 2.13−5.16) and renal composite outcome (HR, 3.41; 95% CI 2.40−5.24). Likewise, pneumonia was also associated with an increased risk of eGFR decline > 40% (HR, 2.47; 95% CI 1.10−5.56) and renal composite outcome (HR, 4.37; 95% CI 2.39−8.02). (4) Conclusions: Our results illustrated the impact of a single infection episode on the future risk of adverse renal events in LT recipients. Whether preventive and prophylactic care bundles against infection and judicious modification of the immunosuppressive regimen benefit renal outcomes may deserve further study.

[Basic nephropathology for pathologists-part 1 : Kidney biopsy-inflammation and immune complexes]

The assessment of kidney biopsies is mainly confined to specialized centres. However, sometimes a kidney biopsy is submitted to a general pathologist, and in addition peritumorous renal parenchyma in tumour nephrectomies can have concomitant non-neoplastic renal disease. Here we present a survey of inflammatory and immunologic changes in all renal compartments, which may in part indicate the need of prompt therapeutic intervention such as in vasculitis, glomerulonephritis and interstitial nephritis. It is important to take into account that renal involvement of vasculitis is mainly centred in glomeruli and only to a much lesser extent in arteries, and that the frequently observed interstitial inflammation very often is an epiphenomenon of another primary kidney disease and not an independent disease process. Typical renal patterns of injury are emphasised.

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.

Tissue Culture Models of AKI: From Tubule Cells to Human Kidney Organoids

AKI affects approximately 13.3 million people around the world each year, causing CKD and/or mortality. The mammalian kidney cannot generate new nephrons after postnatal renal damage and regenerative therapies for AKI are not available. Human kidney tissue culture systems can complement animal models of AKI and/or address some of their limitations. Donor-derived somatic cells, such as renal tubule epithelial cells or cell lines (RPTEC/hTERT, ciPTEC, HK-2, Nki-2, and CIHP-1), have been used for decades to permit drug toxicity screening and studies into potential AKI mechanisms. However, tubule cell lines do not fully recapitulate tubular epithelial cell properties in situ when grown under classic tissue culture conditions. Improving tissue culture models of AKI would increase our understanding of the mechanisms, leading to new therapeutics. Human pluripotent stem cells (hPSCs) can be differentiated into kidney organoids and various renal cell types. Injury to human kidney organoids results in renal cell-type crosstalk and upregulation of kidney injury biomarkers that are difficult to induce in primary tubule cell cultures. However, current protocols produce kidney organoids that are not mature and contain off-target cell types. Promising bioengineering techniques, such as bioprinting and "kidney-on-a-chip" methods, as applied to kidney nephrotoxicity modeling advantages and limitations are discussed. This review explores the mechanisms and detection of AKI in tissue culture, with an emphasis on bioengineered approaches such as human kidney organoid models.

Analysis of Risk Factors for Perioperative Acute Kidney Injury and Management Strategies

Acute kidney injury (AKI) is a serious clinical syndrome, and one of the common comorbidities in the perioperative period. AKI can lead to complications in surgical patients and is receiving increasing attention in clinical workup. In recent years, the analysis of perioperative risk factors has become more in-depth and detailed. In this review, the definition, diagnosis, and pathophysiological characteristics of perioperative AKI are reviewed, and the main risk factors for perioperative AKI are analyzed, including advanced age, gender, certain underlying diseases, impaired clinical status such as preoperative creatinine levels, and drugs that may impair renal function such as non-steroidal anti-inflammatory drugs (NASIDs), ACEI/ARB, and some antibiotics. Injectable contrast agents, some anesthetic drugs, specific surgical interventions, anemia, blood transfusions, hyperglycemia, and malnutrition are also highlighted. We also propose potential preventive and curative measures, including the inclusion of renal risk confirmation in the preoperative assessment, minimization of intraoperative renal toxin exposure, intraoperative management and hemodynamic optimization, remote ischemic preadaptation, glycemic control, and nutritional support. Among the management measures, we emphasize the need for careful perioperative clinical examination, timely detection and management of AKI complications, administration of dexmedetomidine for renal protection, and renal replacement therapy. We aim that this review can further increase clinicians' attention to perioperative AKI, early assessment and intervention to try to reduce the risk of AKI.

Drug-Induced Nephrotoxicity Assessment in 3D Cellular Models

The kidneys are often involved in adverse effects and toxicity caused by exposure to foreign compounds, chemicals, and drugs. Early predictions of these influences are essential to facilitate new, safe drugs to enter the market. However, in current drug treatments, drug-induced nephrotoxicity accounts for 1/4 of reported serious adverse reactions, and 1/3 of them are attributable to antibiotics. Drug-induced nephrotoxicity is driven by multiple mechanisms, including altered glomerular hemodynamics, renal tubular cytotoxicity, inflammation, crystal nephropathy, and thrombotic microangiopathy. Although the functional proteins expressed by renal tubules that mediate drug sensitivity are well known, current in vitro 2D cell models do not faithfully replicate the morphology and intact renal tubule function, and therefore, they do not replicate in vivo nephrotoxicity. The kidney is delicate and complex, consisting of a filter unit and a tubular part, which together contain more than 20 different cell types. The tubular epithelium is highly polarized, and maintaining cellular polarity is essential for the optimal function and response to environmental signals. Cell polarity depends on the communication between cells, including paracrine and autocrine signals, as well as biomechanical and chemotaxis processes. These processes affect kidney cell proliferation, migration, and differentiation. For drug disposal research, the microenvironment is essential for predicting toxic reactions. This article reviews the mechanism of drug-induced kidney injury, the types of nephrotoxicity models (in vivo and in vitro models), and the research progress related to drug-induced nephrotoxicity in three-dimensional (3D) cellular culture models.

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.

Beta-Lactams Toxicity in the Intensive Care Unit: An Underestimated Collateral Damage?

Beta-lactams are the most commonly prescribed antimicrobials in intensive care unit (ICU) settings and remain one of the safest antimicrobials prescribed. However, the misdiagnosis of beta-lactam-related adverse events may alter ICU patient management and impact clinical outcomes. To describe the clinical manifestations, risk factors and beta-lactam-induced neurological and renal adverse effects in the ICU setting, we performed a comprehensive literature review via an electronic search on PubMed up to April 2021 to provide updated clinical data. Beta-lactam neurotoxicity occurs in 10-15% of ICU patients and may be responsible for a large panel of clinical manifestations, ranging from confusion, encephalopathy and hallucinations to myoclonus, convulsions and non-convulsive status epilepticus. Renal impairment, underlying brain abnormalities and advanced age have been recognized as the main risk factors for neurotoxicity. In ICU patients, trough concentrations above 22 mg/L for cefepime, 64 mg/L for meropenem, 125 mg/L for flucloxacillin and 360 mg/L for piperacillin (used without tazobactam) are associated with neurotoxicity in 50% of patients. Even though renal complications (especially severe complications, such as acute interstitial nephritis, renal damage associated with drug induced hemolytic anemia and renal obstruction by crystallization) remain rare, there is compelling evidence of increased nephrotoxicity using well-known nephrotoxic drugs such as vancomycin combined with beta-lactams. Treatment mainly relies on the discontinuation of the offending drug but in the near future, antimicrobial optimal dosing regimens should be defined, not only based on pharmacokinetics/pharmacodynamic (PK/PD) targets associated with clinical and microbiological efficacy, but also on PK/toxicodynamic targets. The use of dosing software may help to achieve these goals.

Exploration of synthesizing fluorescent silicon nanoparticles and label-free detection of sulfadiazine sodium

Herein, silica nanoparticles (SiNPs) with blue-fluorescence have been originally synthesized through one facile hydrothermal way, and this kind of SiNPs were water-soluble with the relative quantum yield of around 6%. Meanwhile, N-(triethoxysilylpropyl) urea severed as the silica source, while potassium hydrogen phthalate as the doping reagent. Also, SiNPs exhibited the acceptable stability and excitation-dependent fluorescence property. Moreover, their surfaces of the obtained SiNPs were equipped with multiple functional groups including -Si-O-Si-, -Si-H, -COOH, -NH₂ and -OH. Importantly, the fluorescence of SiNPs could be specifically quenched by sulfadiazine sodium (SD-Na), thus achieving a label-free detection of SD-Na, which displayed a wide linear response in the range of 0.8 μM-800 μM with a detection limit of 1.02 μM. Additionally, we explored the mechanism of SiNPs sensing SD-Na on the basis of aggregation-induced quenching. To be specific, the particle size of SiNPs increased from 29.9 nm to 203.7 nm induced by the electrostatic interactions between SiNPs and SD-Na, which was further confirmed by high resolution transmission electron microscopy. Consequently, the proposed strategy here broadened the ways of assaying sulfadiazine sodium.

Renal Dysfunction and Tubulopathy Induced by High-Dose Tenofovir Disoproxil Fumarate in C57BL/6 Mice

Tenofovir disoproxil fumarate (TDF) is the most preferred antiretroviral medicine in treating human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections. Recent clinical trials have reported conflicting results on renal toxicity and safety in TDF-treated patients, but reference animal studies, testing high-doses of TDF for renal toxicity, are scarce. In this preclinical study, we investigated whether daily oral TDF administration (200, 500, or 800 mg/kg/d, p.o.) for four weeks induces renal insufficiency in C57BL/6 mice, by evaluating changes in body weight, urine micro-total protein, urinary microalbumin, serum blood urea nitrogen (BUN), and creatinine levels, along with histological examination of kidney samples. In the G3 group (TDF 800 mg/kg/d, p.o.), three mice died on the 17th, 23rd and 26th days, and overall, significant increases in urinary and serum levels were observed after two weeks of TDF treatment. In addition, the proportion of pyknotic epithelial cells and acidophilic cytoplasm in renal tubules was also increased after two weeks, and congestion and hemorrhage were observed in renal tubules after three weeks. Taken together, high-dose TDF treatment of 800 mg/kg/d might lead to renal tubular damage and dysfunction, great enough to cause death in mice, even after a short period of one to two weeks.

A Review on Drug-Induced Nephrotoxicity: Pathophysiological Mechanisms, Drug Classes, Clinical Management, and Recent Advances in Mathematical Modeling and Simulation Approaches

A variety of marketed drugs belonging to various therapeutic classes are known to cause nephrotoxicity. Nephrotoxicity can manifest itself in several forms depending on the specific site involved as well as the underlying pathophysiological mechanisms. As they often coexist with other pathophysiological conditions, the steps that can be taken to treat them are often limited. Thus, drug-induced nephrotoxicity remains a major clinical challenge. Prior knowledge of risk factors associated with special patient populations and specific classes of drugs, combined with early diagnosis, therapeutic drug monitoring with dose adjustments, as well as timely prospective treatments are essential to prevent and manage them better. Most incident drug-induced renal toxicity is reversible only if diagnosed at an early stage and treated promptly. Hence, diagnosis at an early stage is the need of the hour to counter it. Significant recent advances in the identification of novel early biomarkers of nephrotoxicity are not beyond limitations. In such a scenario, mathematical modeling and simulation (M&S) approaches may help to better understand and predict toxicities in a clinical setting. This review summarizes pathophysiological mechanisms of drug-induced nephrotoxicity, classes of nephrotoxic drugs, management, prevention, and diagnosis in clinics. Finally, it also highlights some of the recent advancements in mathematical M&S approaches that could be used to better understand and predict drug-induced nephrotoxicity.

Development of a Drosophila melanogaster based model for the assessment of cadmium and mercury mediated renal tubular toxicity

Xenobiotic mediated renal toxicity is one of the major health concerns to the organisms, including humans. New chemicals with nephrotoxic potential are continuously being added to the list of existing nephrotoxicants. To predict the nephrotoxicity of these new chemicals, reliable and cost-effective alternative animal models are required. It is a prerequisite for the identification and assessment of these compounds as potential nephrotoxicants to prevent renal toxicity in the exposed population. Drosophila melanogaster, a genetically tractable invertebrate animal model, has a renal system functionally analogous to humans. The Malpighian tubules (MTs) of D. melanogaster are similar to the tubular part of nephron of the human kidney. Besides, it recapitulates the renal toxicity hallmark with mammals when exposed to known nephrotoxicants. In this study, first instar larvae of D. melanogaster (Oregon R) were exposed to different concentrations of two well-known nephrotoxicants, cadmium (Cd) and mercury (Hg). Akin to higher organisms, Cd and Hg exposure to D. melanogaster produce similar phenotypes. MTs of exposed D. melanogaster larvae exhibited increased oxidative stress, activated cellular antioxidant defense mechanism, GSH depletion, increased cleaved caspase-3 expression, increased DEVDase activity and increased cell death. The functional status of MTs was assessed by fluid secretion rate (FSR), efflux activity of transporter protein, mitochondrial membrane potential (MMP), ATP level and expression of junctional protein (Dlg). All the phenotypes observed in MTs of D. melanogaster larvae recapitulate the phenotypes observed in higher organisms. Increased uric acid level, the hallmark of renal dysfunction, was also observed in exposed larvae. Taken together, the study suggests that MTs of D. melanogaster may be used as a functional model to evaluate xenobiotic mediated nephrotoxicity.

Hospitalization With Major Infection and Incidence of End-Stage Renal Disease: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

To evaluate whether the incidence of infectious diseases increases the long-term risk for incident end-stage renal disease (ESRD) in the general population.

PATIENTS AND METHODS

In 10,290 participants of the Atherosclerosis Risk in Communities Study who attended visit 4 (1996-1998), we evaluated the association of incident hospitalization with major infections (pneumonia, urinary tract infection, bloodstream infection, and cellulitis and osteomyelitis) with subsequent risk for ESRD through September 30, 2015. Hospitalization with major infection was entered into multivariable Cox models as a time-varying exposure to estimate the hazard ratios.

RESULTS

Mean age was 63 years, and of 10,290 individuals, 56% (n=5781) were women, 22% (n=2252) were black, and 7% (n=666) had an estimated glomerular filtration rate less than 60 mL/min/1.73 m2. During a median follow-up of 17.4 years, there were 2642 incident hospitalizations with major infection and 281 cases of ESRD (132 cases after hospitalization with major infection). The risk for ESRD was higher following major infection compared with while free of major infection (crude incidence rate, 10.9 vs 1.0 per 1000 person-years). In multivariable time-varying Cox analysis, hospitalization with major infection was associated with a 3.3-fold increased risk for ESRD (hazard ratio, 3.34; 95% CI, 2.56-4.37). The association was similar across pneumonia, urinary tract infection, bloodstream infection, and cellulitis and osteomyelitis, and remained significant across subgroups of age, sex, race, diabetes, history of cardiovascular disease, and chronic kidney disease.

CONCLUSION

Hospitalization with major infection was independently and robustly associated with subsequent risk for ESRD. Whether preventive approaches against infection have beneficial effects on kidney outcomes may deserve future investigations.

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.

Mechanisms of antimicrobial-induced nephrotoxicity in children

Drug-induced nephrotoxicity is responsible for 20% to 60% of cases of acute kidney injury in hospitalized patients and is associated with increased morbidity and mortality in both children and adults. Antimicrobials are one of the most common classes of medications prescribed globally and also among the most common causes of nephrotoxicity. A broad range of antimicrobial agents have been associated with nephrotoxicity, but the features of kidney injury vary based on the agent, its mechanism of injury and the site of toxicity within the kidney. Distinguishing nephrotoxicity caused by an antimicrobial agent from other potential inciting factors is important to facilitate both early recognition of drug toxicity and prompt cessation of an offending drug, as well as to avoid unnecessary discontinuation of an innocuous therapy. This review will detail the different types of antimicrobial-induced nephrotoxicity: acute tubular necrosis, acute interstitial nephritis and obstructive nephropathy. It will also describe the mechanism of injury caused by specific antimicrobial agents and classes (vancomycin, aminoglycosides, polymyxins, antivirals, amphotericin B), highlight the toxicodynamics of these drugs and provide guidance on administration or monitoring practices that can mitigate toxicity, when known. Particular attention will be paid to paediatric patients, when applicable, in whom nephrotoxin exposure is an often-underappreciated cause of kidney injury.

Tubulointerstitial nephritis and uveitis (TINU) syndrome: a review

Inflammation of renal interstitium and uveal tissue establishes the two components of tubulointerstitial nephritis and uveitis (TINU) syndrome. Although believed to occur more frequently in young females, a broad spectrum of patients can be affected. Both renal and eye disease can be asymptomatic and may not manifest simultaneously, having independent progressions. Renal disease manifests as acute kidney injury and may cause permanent renal impairment. Eye inflammation can manifest in different anatomical forms, most commonly as bilateral anterior uveitis and may progress to a chronic course. TINU syndrome accounts for approximately 1%–2% of uveitis in tertiary referral centres. A literature review covering the clinical features, pathogenesis, diagnosis and treatment is presented.

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.

Examining the effect of prescription sequence on developing adverse drug reactions: The case of renal failure in diabetic patients

OBJECTIVES

While the effect of medications in development of Adverse Drug Reactions (ADRs) have been widely studied in the past, the literature lacks sufficient coverage in investigating whether the sequence in which [ADR-prone] drugs are prescribed (and administered) can increase the chances of ADR development. The present study investigates this potential effect by applying emergent sequential pattern mining techniques to electronic health records.

MATERIALS AND METHODS

Using longitudinal medication and diagnosis records from more than 377,000 diabetic patients, in this study, we assessed the possible effect of prescription sequences in developing acute renal failure as a prevalent ADR among this group of patients. Relying on emergent sequential pattern mining, two statistical case-control approaches were designed and employed for this purpose.

RESULTS

The results taken from the two employed approaches (i.e. 76.7% total agreement and 68.4% agreement on the existence of some significant effect) provide evidence for the potential effect of prescription sequence on ADRs development evidenced by the discovery that certain sequential patterns occurred more frequently in one group of patients than the other.

CONCLUSION

Given the significant effects shown by our data analyses, we believe that design and implementation of automated clinical decision support systems to constantly monitor patients' medication transactions (and the sequence in which they are administered) and make appropriate alerts to prevent certain possible ADRs, may decrease ADR occurrences and save lives and money.

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.

A critical review of adverse effects to the kidney: mechanisms, data sources, and in silico tools to assist prediction

INTRODUCTION

The kidney is a major target for toxicity elicited by pharmaceuticals and environmental pollutants. Standard testing which often does not investigate underlying mechanisms has proven not to be an adequate hazard assessment approach. As such, there is an opportunity for the application of computational approaches that utilize multiscale data based on the Adverse Outcome Pathway (AOP) paradigm, coupled with an understanding of the chemistry underpinning the molecular initiating event (MIE) to provide a deep understanding of how structural fragments of molecules relate to specific mechanisms of nephrotoxicity. Aims covered: The aim of this investigation was to review the current scientific landscape related to computational methods, including mechanistic data, AOPs, publicly available knowledge bases and current in silico models, for the assessment of pharmaceuticals and other chemicals with regard to their potential to elicit nephrotoxicity. A list of over 250 nephrotoxicants enriched with, where possible, mechanistic and AOP-derived understanding was compiled. Expert opinion: Whilst little mechanistic evidence has been translated into AOPs, this review identified a number of data sources of in vitro, in vivo, and human data that may assist in the development of in silico models which in turn may shed light on the interrelationships between nephrotoxicity mechanisms.

Quetiapine-related Acute Kidney Injury Requiring Transient Continuous Hemodiafiltration

A 73-year-old man, with congestive heart failure due to combined valvar disease, underwent curative surgery. Although the surgery was successful, his clinical course was eventful because of pulmonary complications, and he began to deteriorate mentally. Quetiapine was prescribed, which appeared to effectively settle his mental status. Following the administration of quetiapine, however, he developed acute kidney injury (AKI) that required continuous hemodiafiltration. Subsequent to discontinuation of quetiapine, his renal function gradually improved. Atypical antipsychotic drugs, including quetiapine, are frequently used to treat delirium in elderly patients in the intensive-care setting. This case highlights a potential risk of quetiapine-related AKI.

[Drug nephrotoxicity]

Drug-induced nephrotoxicity (DIN) remains a current problem with economic and medical consequences. It affects all nephron segments. Recovery of renal function is based on the identification of risk factors, early diagnosis of renal disease, rapid (if possible) cessation of the causative agent and, in some cases, adjunctive therapy. Prevention is based on identification of early markers of DIN, correction of risk factors, initial assessment of renal function for adequate dosage adjustment and exclusion of other nephrotoxic factors. It has recently been proposed to standardize the phenotype of iatrogenic renal disease and, on the other hand, new markers of renal toxicity allowing early diagnosis and therefore better management of nephrotoxicity.

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.

Medication-Induced Interstitial Nephritis in the 21st Century

Interstitial nephritis is an immune mediated form of tubulointerstitial kidney injury that may occur secondary to drugs, autoimmune disease, infections, and hematologic disorders or as a reactive process. Drug-induced acute interstitial nephritis (DI-AIN) occurs in 0.5%-3% of all kidney biopsies and in 5%-27% of biopsies performed for acute kidney injury. Drugs are implicated in 70%-90% of biopsy-proved IN with a prevalence of 50% in less developed to 78% in more developed countries. DI-AIN typically is idiosyncratic because of a delayed hypersensitivity reaction, although some chemotherapeutic agents are permissive for immune upregulation and injure the kidney in a dose-related manner. Antibiotics are the most implicated class of medication in DI-AIN, followed by proton pump inhibitors, nonsteroidal anti-inflammatory agents, and 5-aminosalicylates. Diuretics, allopurinol, phenytoin and other anti-seizure medications, and H2 receptor antagonists are known offenders while chemotherapeutic agents are an under-recognized cause. The symptoms of DI-AIN are variable and often not specific; thus, kidney biopsy is required to make a firm diagnosis. The incidence of DI-AIN appears to be increasing, particularly in the elderly in whom kidney biopsy is underused, and identification of the offending agent may be complicated by polypharmacy. As rapid drug discontinuation may improve prognosis, the possibility of DI-AIN should always be considered in a patient with acute kidney injury.

Development and Application of Human Renal Proximal Tubule Epithelial Cells for Assessment of Compound Toxicity

Kidney toxicity is a major problem both in drug development and clinical settings. It is difficult to predict nephrotoxicity in part because of the lack of appropriate in vitro cell models, limited endpoints, and the observation that the activity of membrane transporters which plays important roles in nephrotoxicity by affecting the pharmacokinetic profile of drugs is often not taken into account. We developed a new cell model using pseudo-immortalized human primary renal proximal tubule epithelial cells. This cell line (SA7K) was characterized by the presence of proximal tubule cell markers as well as several functional properties, including transporter activity and response to a few well-characterized nephrotoxicants. We subsequently evaluated a group of potential nephrotoxic compounds in SA7K cells and compared them to a commonly used human immortalized kidney cell line (HK-2). Cells were treated with test compounds and three endpoints were analyzed, including cell viability, apoptosis and mitochondrial membrane potential. The results showed that most of the known nephrotoxic compounds could be detected in one or more of these endpoints. There were sensitivity differences in response to several of the chemicals between HK-2 and SA7K cells, which may relate to differences in expressions of key transporters or other components of nephrotoxicity pathways. Our data suggest that SA7K cells appear as promising for the early detection of renal toxicants.

The potential protective role of taurine against 5-fluorouracil-induced nephrotoxicity in adult male rats

Nephrotoxicity is common with the use of the chemotherapeutic agent 5-Fluorouracil (5-FU). The current study aimed to investigate the probable protective effect of taurine (TAU) against 5-FU-induced nephrotoxicity in rats using biochemical, histological and ultrastructural approaches. Twenty-four rats were equally divided into control, TAU, 5-FU and 5-FU+TAU groups. 5-FU significantly elevated levels of blood urea nitrogen (BUN), creatinine, and uric acid; while it reduced activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Also, 5-FU induced significant elevation in malondialdehyde (MDA) levels accompanied with marked decline in γ-glutamyltranspeptidase (GGT) and alkaline phosphatase (AP) levels in kidney tissues. These biochemical alterations were accompanied by histopathological changes marked by destruction of the normal renal structure, in addition to ultrastructural alterations represented by thickened and irregular glomerular basement membranes, congested glomerular capillaries, damaged lining fenestrated endothelium, mesangial cells hyperplasia with expanded mesangial matrix, and distorted podocyte's processes. Also, the proximal (PCT) and distal (DCT) convoluted tubules showed thickened basement membranes, destructed apical microvilli and loss of basal infoldings of their epithelial cells. Administration of TAU to 5-FU-treated rats reversed most of the biochemical, histological, and ultrastructural alterations. These results indicate that TAU has a protective effect against 5-FU-induced nephrotoxicity.

Role of Oxidative Stress in Drug-Induced Kidney Injury

The kidney plays a primary role in maintaining homeostasis and detoxification of numerous hydrophilic xenobiotics as well as endogenous compounds. Because the kidney is exposed to a larger proportion and higher concentration of drugs and toxins than other organs through the secretion of ionic drugs by tubular organic ion transporters across the luminal membranes of renal tubular epithelial cells, and through the reabsorption of filtered toxins into the lumen of the tubule, these cells are at greater risk for injury. In fact, drug-induced kidney injury is a serious problem in clinical practice and accounts for roughly 20% of cases of acute kidney injury (AKI) among hospitalized patients. Therefore, its early detection is becoming more important. Usually, drug-induced AKI consists of two patterns of renal injury: acute tubular necrosis (ATN) and acute interstitial nephritis (AIN). Whereas AIN develops from medications that incite an allergic reaction, ATN develops from direct toxicity on tubular epithelial cells. Among several cellular mechanisms underlying ATN, oxidative stress plays an important role in progression to ATN by activation of inflammatory response via proinflammatory cytokine release and inflammatory cell accumulation in tissues. This review provides an overview of drugs associated with AKI, the role of oxidative stress in drug-induced AKI, and a biomarker for drug-induced AKI focusing on oxidative stress.

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.

Analgesic Nephropathy–-A Painful Progression

One of the dreaded complications of long term analgesic intake is nephrotoxicity characterized by chronic interstitial nephritis and papillary necrosis. Much of the literature of its epidemiology dates back to 1960s and its impact on present day society is not well documented. Non steroidal anti inflammatory agents reduce pain by blocking prostaglandin generation. Prostaglandins have renal vaso dilatory effects in states of volume depletion to counteract the vasoconstrictive pressor hormones. Earlier analgesic tablets contained a mixture of aspirin, phenacetin and caffeine. Phenacetin and its metabolites have nephrotoxic potential and incidence of analgesic nephropathy was brought down in countries where it was banned. The concentration of phenacetin and its metabolite acetaminophen is increased at the tip of renal papilla due to counter current concentrating mechanism of the loop of henle. These are potent oxidants leading to cell injury due to lipid peroxidation, though their effects are normally counterbalanced by anti oxidant glutathione. Glutathione deficiency at the medulla can be precipitated by co ingestion of aspirin. The exact dose of analgesics which needs to be ingested is unclear but a daily ingestion of 5–8 tablets over 5 years results in clinical nephrotoxicity. The histopathology is one of chronic interstitial nephritis with renal fibrosis. Clinically the patient presents with polyuria, asthenia and anemia. The diagnosis is suspected in a patient with progressive chronic kidney disease without proteinuria. CT imaging of the kidneys show irregular scarred kidneys with papillary calcification and necrosis. Recently, COX-2 inhibitors are promoted as renal safe drugs, but may not be so given the multiple case reports of renal toxicity in post marketing surveys. The treatment of analgesic nephropathy includes discontinuation of offending drug, protein restricted diet, control of blood pressure and statins. In conclusion analgesic nephropathy is a preventable cause of chronic kidney disease and both the patients and treating physicians should be mindful of the potential nephrotoxcity of nonsteroidal anti inflammatory agents when administered for prolonged periods without monitoring renal function.

Polymyxin B Nephrotoxicity: From Organ to Cell Damage

Polymyxins have a long history of dose-limiting toxicity, but the underlying mechanism of polymyxin B-induced nephrotoxicity is unclear. This study investigated the link between the nephrotoxic effects of polymyxin B on renal metabolic functions and mitochondrial morphology in rats and on the structural integrity of LLC-PK1 cells. Fifteen Wistar rats were divided into two groups: Saline group, rats received 3 mL/kg of 0.9% NaCl intraperitoneally (i.p.) once a day for 5 days; Polymyxin B group, rats received 4 mg/kg/day of polymyxin B i.p. once a day for 5 days. Renal function, renal hemodynamics, oxidative stress, mitochondrial injury and histological characteristics were assessed. Cell membrane damage was evaluated via lactate dehydrogenase and nitric oxide levels, cell viability, and apoptosis in cells exposed to 12.5 μM, 75 μM and 375 μM polymyxin B. Polymyxin B was immunolocated using Lissamine rhodamine-polymyxin B in LLC-PK1 cells. Polymyxin B administration in rats reduced creatinine clearance and increased renal vascular resistance and oxidative damage. Mitochondrial damage was confirmed by electron microscopy and cytosolic localization of cytochrome c. Histological analysis revealed tubular dilatation and necrosis in the renal cortex. The reduction in cell viability and the increase in apoptosis, lactate dehydrogenase levels and nitric oxide levels confirmed the cytotoxicity of polymyxin B. The incubation of LLC-PK1 cells resulted in mitochondrial localization of polymyxin B. This study demonstrates that polymyxin B nephrotoxicity is characterized by mitochondrial dysfunction and free radical generation in both LLC-PK1 cells and rat kidneys. These data also provide support for clinical studies on the side effects of polymyxin B.