Vancomycin induces reactive oxygen species-dependent apoptosis via mitochondrial cardiolipin peroxidation in renal tubular epithelial cells

Leonurine alleviates vancomycin nephrotoxicity via activating PPARγ and inhibiting the TLR4/NF-κB/TNF-α pathway

Vancomycin (VCM) is the first-line antibiotic for severe infections, but nephrotoxicity limits its use. Leonurine (Leo) has shown protective effects against kidney damage. However, the effect and mechanism of Leo on VCM nephrotoxicity remain unclear. In this study, mice and HK-2 cells exposed to VCM were treated with Leo. Biochemical and pathological analysis and fluorescence probe methods were performed to examine the role of Leo in VCM nephrotoxicity. Immunohistochemistry, q-PCR, western blot, FACS, and Autodock software were used to verify the mechanism. The present results indicate that Leo significantly alleviates VCM-induced renal injury, morphological damage, and oxidative stress. Increased intracellular and mitochondrial ROS in HK-2 cells and decreased mitochondrial numbers in mouse renal tubular epithelial cells were reversed in Leo-administrated groups. In addition, molecular docking analysis using Autodock software revealed that Leo binds to the PPARγ protein with high affinity. Mechanistic exploration indicated that Leo inhibited VCM nephrotoxicity via activating PPARγ and inhibiting the TLR4/NF-κB/TNF-α inflammation pathway. Taken together, our results indicate that the PPARγ inhibition and inflammation reactions were implicated in the VCM nephrotoxicity and provide a promising therapeutic strategy for renal injury.

Mitochondrial electron transport chain in macrophage reprogramming: Potential role in antibacterial immune response

Macrophages restrain microbial infection and reinstate tissue homeostasis. The mitochondria govern macrophage metabolism and serve as pivot in innate immunity, thus acting as immunometabolic regulon. Metabolic pathways produce electron flows that end up in mitochondrial electron transport chain (mtETC), made of super-complexes regulating multitude of molecular and biochemical processes. Cell-intrinsic and extrinsic factors influence mtETC structure and function, impacting several aspects of macrophage immunity. These factors provide the macrophages with alternate fuel sources and metabolites, critical to gain functional competence and overcoming pathogenic stress. Mitochondrial reactive oxygen species (mtROS) and oxidative phosphorylation (OXPHOS) generated through the mtETC are important innate immune attributes, which help macrophages in mounting antibacterial responses. Recent studies have demonstrated the role of mtETC in governing mitochondrial dynamics and macrophage polarization (M1/M2). M1 macrophages are important for containing bacterial pathogens and M2 macrophages promote tissue repair and wound healing. Thus, mitochondrial bioenergetics and metabolism are intimately coupled with innate immunity. In this review, we have addressed mtETC function as innate rheostats that regulate macrophage reprogramming and innate immune responses. Advancement in this field encourages further exploration and provides potential novel macrophage-based therapeutic targets to control unsolicited inflammation.

Understanding vancomycin nephrotoxicity augmented by β-lactams: a synthesis of endosymbiosis, proximal renal tubule mitochondrial metabolism, and β-lactam chemistry

The recent understanding that hydrophobic β-lactams have greater affinity for organic anion transporter-3 (OAT-3) of the proximal renal tubule could provide valuable insights for anticipating β-lactams that may exacerbate vancomycin-induced nephrotoxicity. Vancomycin alone provides oxidative stress on the highly metabolic proximal tubular cells. Hydrophobic β-lactams (eg, piperacillin and anti-staphylococcal β-lactams) could have greater OAT-3 mediated uptake into proximal tubular cells than hydrophilic β-lactams (eg, most cephalosporins and carbapenems), thereby causing greater mitochondrial stress on these susceptible cells. It remains to be seen whether concomitant drugs that inhibit OAT-3 mediated cellular uptake of β-lactams into proximal tubular cells or provide antioxidant effects might mitigate β-lactam augmented vancomycin nephrotoxicity. Furthermore, the serum creatinine rise seen with vancomycin and hydrophobic β-lactams might represent competition for creatinine-secreting transporters (of which OAT-3 is one), thus, indicating creatinine retention rather than renal injury. In the meantime, clinicians are advised to utilise less nephrotoxic combinations in both empirical and directed antibiotic selection settings until further research is conducted.

In Vitro Evaluation of Vancomycin-Induced Toxicity in Human Primary Knee Chondrocytes

Septic arthritis as a complication of orthopaedic joint surgery can have catastrophic outcomes for patients. To minimise infection risk associated with elective orthopaedics, topical vancomycin during surgery has become increasingly common. Evidence suggests that high concentrations of vancomycin, following direct application of the drug to the joint, are toxic towards various local cell types in the joint, including chondrocytes. However, the mechanism of this vancomycin tissue toxicity is yet to be determined. The aim of this study was to evaluate the toxicity of vancomycin on chondrocytes and the mechanisms of cell death involved. Human primary knee chondrocytes were exposed to vancomycin (1.25-10 mg/mL) for 24 h and their viability assessed using the resazurin reduction assay in vitro. Specific cell death mechanisms and their contributors, including reactive oxygen species (ROS) production and apoptosis, were measured. This study showed that high concentrations of vancomycin (5 and 10 mg/mL) were toxic towards human primary knee chondrocyte cells, while lower concentrations (1.25 and 2.5 mg/mL) were not. Cell death studies found that this occurred through an apoptotic pathway. This study provides additional support that vancomycin in high doses is toxic towards chondrocytes and preliminary evidence that this toxicity occurs via apoptotic cell death mechanisms.

Duration of Simultaneous Exposure to High-Risk and Lower-Risk Nephrotoxic Antimicrobials in the Neonatal Intensive Care Unit (NICU) and Future Adolescent Kidney Health

OBJECTIVE

To determine whether greater duration of simultaneous exposure to antimicrobials with high nephrotoxicity risk combined with lower-risk antimicrobials (simultaneous exposure) in the neonatal intensive care unit (NICU) is associated with worse later kidney health in adolescents born preterm with very low birth weight (VLBW).

STUDY DESIGN

Prospective cohort study of participants born preterm with VLBW (<1500 g) as singletons between January 1, 1992, and June 30, 1996. We defined simultaneous exposure as a high-risk antimicrobial, such as vancomycin, administered with a lower-risk antimicrobial on the same date in the NICU. Outcomes were serum creatinine, estimated glomerular filtration rate (eGFR), and first-morning urine albumin-creatinine ratio (ACR) at age 14 years. We fit multivariable linear regression models with days of simultaneous exposure and days of nonsimultaneous exposure as main effects, adjusting for gestational age, birth weight, and birth weight z-score.

RESULTS

Of the 147 out of 177 participants who had exposure data, 97% received simultaneous antimicrobials for mean duration 7.2 days (SD 5.6). No participant had eGFR <90 ml/min/1.73 m2. The mean ACR was 15.2 mg/g (SD 38.7) and 7% had albuminuria (ACR >30 mg/g). Each day of simultaneous exposure was associated only with a 1.04-mg/g higher ACR (95% CI 1.01 to 1.06).

CONCLUSIONS

Despite frequent simultaneous exposure to high-risk combined with lower-risk nephrotoxic antimicrobials in the NICU, there were no clinically relevant associations with worse kidney health identified in adolescence. Although future studies are needed, these findings may provide reassurance in a population thought to be at increased risk of chronic kidney disease.

A review on oxidant and antioxidant effects of antibacterial agents: impacts on bacterial cell death and division and therapeutic effects or adverse reactions in humans

Reactive oxygen species (ROS) are produced in the mitochondrial respiratory pathway and cellular metabolism. They are responsible for creating oxidative stress and lipid peroxidation. In living organisms, there is a balance between oxidative stress and the antioxidant system, but some factors such as medicines disturb the balance and cause many problems. These effects can impact bacterial death and division and also in humans can induce therapeutic or adverse reactions. Web of Science and Pubmed databases were used for searching. This review focuses on the oxidant and antioxidant effects of different classes of antibacterial agents and the mechanisms of oxidative stress. Some of these agents have beneficial effects on killing bacteria due to their antioxidant or oxidant effects. However, some of their side effects may be due to their oxidative effects. Based on the results of this review, minocycline is an antioxidant, but aminoglycosides, chloramphenicol, glycopeptides, antituberculosis drugs, fluoroquinolones, and sulfamethoxazole agents have oxidant effects. Furthermore, cephalosporins, penicillins, metronidazole, and macrolides have both oxidant and antioxidant effects in different studies. It is concluded that some antibacterial agents have oxidant and other antioxidant effects. These activities may affect their therapeutic effects or side effects. Some antioxidants can prevent the adverse effects of antibacterial agents. Clarifying the exact oxidant and antioxidant effects of some antimicrobial agents needs more research projects.

Side effects of antibiotics and perturbations of mitochondria functions

Antibiotics are one of the greatest discoveries of medicine of the past century. Despite their invaluable contribution to infectious disease, their administration could lead to side effects that in some cases are serious. The toxicity of some antibiotics is in part due to their interaction with mitochondria: these organelles derive from a bacterial ancestor and possess specific translation machinery that shares similarities with the bacterial counterpart. In other cases, the antibiotics could interfere with mitochondrial functions even if their main bacterial targets are not shared with the eukaryotic cells. The purpose of this review is to summarize the effects of antibiotics administration on mitochondrial homeostasis and the opportunity that some of these molecules could represent in cancer treatment. The importance of antimicrobial therapy is unquestionable, but the identification of interaction with eukaryotic cells and in particular with mitochondria is crucial to reduce the toxicity of these drugs and to explore other useful medical applications.

Nephrotoxicity of Vancomycin in Combination With Beta-Lactam Agents: Ceftolozane-Tazobactam vs Piperacillin-Tazobactam

BACKGROUND

Vancomycin (VAN)-associated acute kidney injury (AKI) is increased when VAN is combined with certain beta-lactams (BLs) such as piperacillin-tazobactam (TZP) but has not been evaluated with ceftolozane-tazobactam (C/T). Our aim was to investigate the AKI incidence of VAN in combination with C/T (VAN/C/T) compared with VAN in combination to TZP (VAN-TZP).

METHODS

We conducted a multicenter, observational, comparative study across the United States. The primary analysis was a composite outcome of AKI and risk, injury, failure, loss, end stage renal disease; Acute Kidney Injury Network; or VAN-induced nephrotoxicity according to the consensus guidelines. Multivariable logistic regression analysis was conducted to adjust for confounding variables and stratified Kaplan-Meir analysis to assess the time to nephrotoxicity between the 2 groups.

RESULTS

We included VAN/C/T (n = 90) and VAN-TZP (n = 284) at an enrollment ratio of 3:1. The primary outcome occurred in 12.2% vs 25.0% in the VAN-C/T and VAN-TZP groups, respectively (P = .011). After adjusting for confounding variables, VAN-TZP was associated with increased odds of AKI compared with VAN-C/T; with an adjusted odds ratio of 3.308 (95% confidence interval, 1.560-6.993). Results of the stratified Kaplan-Meir analysis with log-rank time-to-nephrotoxicity analysis indicate that time to AKI was significantly shorter among patients who received VAN-TZP (P = .004). Cox proportional hazards analysis demonstrated that TZP was consistent with the primary analysis (P = .001).

CONCLUSIONS

Collectively, our results suggest that the AKI is not likely to be related to tazobactam but rather to piperacillin, which is a component in VAN-TZP but not in VAN-C/T.

Comparative renal risk of long-term use of beta-lactams in combination with vancomycin across the continuum of care

Background

Data are controversial regarding nephrotoxicity risk with vancomycin plus piperacillin-tazobactam (VPT) compared to vancomycin alone or in combination with other beta-lactams (BLs) in acute care use. Furthermore, data are lacking on the incidence of acute kidney injury (AKI) with long-term use of VPT including outpatient parenteral antimicrobial therapy (OPAT).

Methods

This retrospective study included 826 adult patients on an intravenous vancomycin plus BL for ⩾2 weeks, including cefepime, piperacillin/tazobactam, ertapenem, or meropenem, from August 2017 to January 2022. The primary outcome was incidence of AKI. Univariate and multivariable Cox proportional hazard regression analyses were conducted to adjust for confounding variables. A secondary analysis based on the propensity score (PS)-matched cohort was performed.

Results

AKI occurred in 14.4% of patients in the VPT group (n = 15/104) compared to 5.5% in the other BL group (n = 40/722) (p < 0.001). Average time to AKI from start of combination therapy was 9.4 (1.7-12.0) days in the VPT group and 10.9 (5-22.7) days in the other BL group (p = 0.20). The median duration of vancomycin and BL in the overall cohort was approximately 1 month. Beyond BL selection, patient characteristics were not associated with AKI other than the receipt of concomitant acyclovir [hazard ratio (HR) 2.48 (95% confidence interval (CI): 1.33-4.65), p = 0.004]. In the PS-matched cohort, AKI occurred in 14.4% of patients in the VPT group (n = 15/104) and 5.3% in the other BL group (n = 11/208) (p = 0.006). Receipt of VPT [HR: 2.55 (1.36-4.78), p = 0.004] and acyclovir [HR: 2.38 (1.19-4.74), p = 0.014) remained significantly associated with AKI in the multivariable model.

Conclusion

Clinicians should exercise caution when using VPT for >2 weeks, including in the OPAT setting, even when no renal dysfunction is observed during the initial week of combination therapy.

Blood Biomarkers and Metabolomic Profiling for the Early Diagnosis of Vancomycin-Associated Acute Kidney Injury: A Systematic Review and Meta-Analysis of Experimental Studies

Background: several blood-based biomarkers have been proposed for predicting vancomycin-associated kidney injury (VIKI). However, no systematic analysis has compared their prognostic value. Objective: this systematic review and meta-analysis was designed to investigate the role of blood biomarkers and metabolomic profiling as diagnostic and prognostic predictors in pre-clinical studies of VIKI. Methods: a systematic search of PubMed was conducted for relevant articles from January 2000 to May 2022. Animal studies that administered vancomycin and studied VIKI were eligible for inclusion. Clinical studies, reviews, and non-English literature were excluded. The primary outcome was to investigate the relationship between the extent of VIKI as measured by blood biomarkers and metabolomic profiling. Risk of bias was assessed with the CAMARADES checklist the SYRCLE’s risk of bias tool. Standard meta-analysis methods (random-effects models) were used. Results: there were four studies for the same species, dosage, duration of vancomycin administration and measurement only for serum creatine and blood urea nitrogen in rats. A statistically significant increase was observed between serum creatinine in the vancomycin group compared to controls (pooled p = 0.037; Standardized Mean Difference: 2.93; 95% CI: 0.17 to 5.69; I² = 92.11%). Serum BUN levels were not significantly different between control and vancomycin groups (pooled p = 0.11; SMD: 3.05; 95% CI: 0.69 to 6.8; I² = 94.84%). We did not identify experimental studies using metabolomic analyses in animals with VIKI. Conclusions: a total of four studies in rodents only described outcomes of kidney injury as defined by blood biomarkers. Blood biomarkers represented included serum creatinine and BUN. Novel blood biomarkers have not been explored.

Comparing the pharmacokinetics and organ/tissue distribution of anti-methicillin-resistant Staphylococcus aureus agents using a rat model of sepsis

Sepsis is a major cause of death, and sepsis-derived physiological changes complicate the understanding of drug distribution in organs/tissues, which determines the efficacy and toxicity of antimicrobial agents. In this study, we evaluated and compared the pharmacokinetics of methicillin-resistant Staphylococcus aureus treatment agents in sepsis with that of vancomycin, arbekacin, linezolid, and daptomycin.Rat models of sepsis were prepared using cecal ligation puncture. The pharmacokinetics of vancomycin, arbekacin, linezolid, and daptomycin were evaluated using their drug concentration profiles in plasma, kidneys, liver, lungs, skin, and muscles after intravenous administration in normal and septic rats.The kidney/plasma concentration ratio was higher in septic rats than in normal rats for vancomycin, arbekacin, and daptomycin but not for linezolid. The increase in the kidney/plasma concentration ratio for vancomycin was time-dependent, indicating an association between sepsis and stasis of vancomycin in the kidneys. In contrast, the distribution of linezolid from the blood to the organs/tissues in septic rats was comparable to that in normal rats.Sepsis-induced nephrotoxicity results in the stasis of vancomycin in the kidney, suggesting that this exacerbates proximal tubular epithelial cell injury. No dose modification of linezolid may be required for patients with sepsis.

Vancomycin-Associated Acute Kidney Injury: A Narrative Review from Pathophysiology to Clinical Application

Vancomycin is the most frequently used antibiotic, accounting for up to 35% of hospitalized patients with infection, because of its optimal bactericidal effectiveness and relatively low price. Vancomycin-associated AKI (VA-AKI) is a clinically relevant but not yet clearly understood entity in critically ill patients. The current review comprehensively summarizes the pathophysiological mechanisms of, biomarkers for, preventive strategies for, and some crucial issues with VA-AKI. The pathological manifestations of VA-AKI include acute tubular necrosis, acute tubulointerstitial nephritis (ATIN), and intratubular crystal obstruction. The proposed pathological mechanisms of VA-AKI include oxidative stress and allergic reactions induced by vancomycin and vancomycin-associated tubular casts. Concomitant administration with other nephrotoxic antibiotics, such as piperacillin–tazobactam, high vancomycin doses, and intermittent infusion strategies compared to the continuous infusion are associated with a higher risk of VA-AKI. Several biomarkers could be applied to predict and diagnose VA-AKI. To date, no promising therapy is available. Oral steroids could be considered for patients with ATIN, whereas hemodialysis might be applied to remove vancomycin from the patient. In the future, disclosing more promising biomarkers that could precisely identify populations susceptible to VA-AKI and detect VA-AKI occurrence early on, and developing pharmacological agents that could prevent or treat VA-AKI, are the keys to improve the prognoses of patients with severe infection who probably need vancomycin therapy.

Anti-oxidant, anti-apoptotic, and mitochondrial regulatory effects of selenium nanoparticles against vancomycin induced nephrotoxicity in experimental rats

AIM

Nephrotoxicity is the major limiting factor for the clinical use of vancomycin (VCM) for treatment against multi-resistant Gram-positive bacteria. The present research aimed to investigate the ability of selenium nanoparticles (SeNPs) to protect against VCM-induced nephrotoxicity in rats.

MAIN METHODS

Experimental rats were divided into five groups; the first was the normal control, the second was treated with VCM (200 mg/kg twice/day, i.p.) for 7 days. The third, fourth, and fifth groups were treated orally with SeNPs (0.5, 1, and 2 mg/kg/day); respectively. SeNPs were administered for 12 days before VCM, 1 week simultaneously with VCM, and for another 1 week after its administration.

KEY FINDINGS

Levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and kidney injury molecule-1 (KIM-1) were significantly increased in kidney tissue after VCM administration. Expression of adenosine 5'-monophosphate-activated protein kinase (AMPK), Bcl-2 associated X protein (Bax), caspase 3 and caspase 9 in kidney tissue was significantly increased, while the antioxidant enzymes, mitochondrial complexes, the ATP levels and B-cell lymphoma protein 2 (Bcl-2) were decreased in kidney in the VCM-treated rats compared to the normal control group. Treatment with SeNPs significantly decreased levels of MDA, iNOS, NO, TNF-α, and KIM-1 in the kidney tissue. Administration of SeNPs also downregulated the expression of the proapoptotic agents and enhanced the activities of the antioxidant enzymes and the mitochondrial enzyme complexes in the kidney.

SIGNIFICANCE

SeNPs alleviated VCM-induced nephrotoxicity through their anti-oxidant, anti-inflammatory, anti-apoptotic and mitochondrial protective effects.

Use of in vitro metabolomics in NRK cells to help predicting nephrotoxicity and differentiating the MoA of nephrotoxicants

We describe a strategy using an in vitro metabolomics assay with tubular rat NRK-52E cells to investigate the Modes of Action (MoAs) of nephrotoxic compounds. Chemicals were selected according to their MoAs based on literature information: acetaminophen, 4-aminophenol and S-(trichlorovinyl-)L-cysteine (TCVC), (covalent protein binding); gentamycin, vancomycin, polymycin B and CdCl₂ (lysosomal overload) and tenofovir and cidofovir (mitochondrial DNA-interaction). After treatment and harvesting of the cells, intracellular endogenous metabolites were quantified relative to vehicle control. Metabolite patterns were evaluated in a purely data-driven pattern generation process excluding published information. This strategy confirmed the assignment of the chemicals to the respective MoA except for TCVC and CdCl₂. Finally, TCVC was defined as unidentified and CdCl₂ was reclassified to the MoA "covalent protein binding". Hierarchical cluster analysis of 58 distinct metabolites from the patterns enabled a clear visual separation of chemicals in each MoA. The assay reproducibility was very good and metabolic responses were consistent. These results support the use of metabolome analysis in NRK-52E cells as a suitable tool for understanding and investigating the MoA of nephrotoxicants. This assay could enable the early identification of nephrotoxic compounds and finally reduce animal testing.

Docosahexaenoic Acid Inhibits Cytokine Expression by Reducing Reactive Oxygen Species in Pancreatic Stellate Cells

Pancreatic stellate cells (PSCs) are activated by inflammatory stimuli, such as TNF-α or viral infection. Activated PSCs play a crucial role in the development of chronic pancreatitis. Polyinosinic-polycytidylic acid (poly (I:C)) is structurally similar to double-stranded RNA and mimics viral infection. Docosahexaenoic acid (DHA) exhibits anti-inflammatory activity. It inhibited fibrotic mediators and reduced NF-κB activity in the pancreas of mice with chronic pancreatitis. The present study aimed to investigate whether DHA could suppress cytokine expression in PSCs isolated from rats. Cells were pre-treated with DHA or the antioxidant N-acetylcysteine (NAC) and stimulated with TNF-α or poly (I:C). Treatment with TNF-α or poly (I:C) increased the expression of monocyte chemoattractant protein 1 (MCP-1) and chemokine C-X3-C motif ligand 1 (CX3CL1), which are known chemoattractants, and enhanced intracellular and mitochondrial reactive oxygen species (ROS) production and NF-κB activity, but reduced mitochondrial membrane potential (MMP). Increased intracellular and mitochondrial ROS accumulation, cytokine expression, MMP disruption, and NF-κB activation were all prevented by DHA in TNF-α- or poly (I:C)-treated PSCs. NAC suppressed TNF-α- or poly (I:C)-induced expression of MCP-1 and CX3CL1. In conclusion, DHA inhibits poly (I:C)- or TNF-α-induced cytokine expression and NF-κB activation by reducing intracellular and mitochondrial ROS in PSCs. Consumption of DHA-rich foods may be beneficial in preventing chronic pancreatitis by inhibiting cytokine expression in PSCs.

Vitamin C reduces vancomycin-related nephrotoxicity through the inhibition of oxidative stress, apoptosis, and inflammation in mice

Background

Vancomycin (VCM) is an antibiotic widely used to treat a range of serious bacterial infections; however, it is associated with nephrotoxicity. Vitamin C (VC) is a classical antioxidant that can alleviate various organ injuries and inflammatory responses by reducing inflammation and oxidative stress. This study aimed to examine the effect of VC on VCM-related nephrotoxicity in mice.

Methods

Mice were randomized into four groups: control, VCM (400 mg/kg/day), VCM (400 mg/kg/day) + VC (200 mg/kg/day), and VC (200 mg/kg/day) groups. Both VCM and VC were administered via intraperitoneal injection for 7 d, after which kidney and blood samples were collected and evaluated. Creatinine (Cr), blood urea nitrogen (BUN), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and nuclear factor-κB (NF-κB) were measured.

Results

In the VCM group, kidney index, renal injury score, cell apoptosis, serum Cr and BUN, and kidney Cr, BUN, MDA, IL-1β, IL-6, TNF-α, and NF-κB were higher compared to the control group (all P<0.05), while body weight and kidney SOD activity were lower (both P<0.05). By contrast, no differences were observed between the control and VC groups (VC and VCM + VC groups) for all these indicators.

Conclusions

The antioxidant VC reduces VCM-related renal injury by reducing oxidative stress, cell apoptosis, and inflammation.

Metabolic and Lipidomic Assessment of Kidney Cells Exposed to Nephrotoxic Vancomycin Dosages

Vancomycin is a glycopeptide antibiotic used against multi-drug resistant gram-positive bacteria such as Staphylococcus aureus (MRSA). Although invaluable against resistant bacteria, vancomycin harbors adverse drug reactions including cytopenia, ototoxicity, as well as nephrotoxicity. Since nephrotoxicity is a rarely occurring side effect, its mechanism is incompletely understood. Only recently, the actual clinically relevant concentration the in kidneys of patients receiving vancomycin was investigated and were found to exceed plasma concentrations by far. We applied these clinically relevant vancomycin concentrations to murine and canine renal epithelial cell lines and assessed metabolic and lipidomic alterations by untargeted and targeted gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry analyses. Despite marked differences in the lipidome, both cell lines increased anabolic glucose reactions, resulting in higher sorbitol and lactate levels. To the best of our knowledge, this is the first endometabolic profiling of kidney cells exposed to clinically relevant vancomycin concentrations. The presented study will provide a valuable dataset to nephrotoxicity researchers and might add to unveiling the nephrotoxic mechanism of vancomycin.

Vancomyxins: Vancomycin-Polymyxin Nonapeptide Conjugates That Retain Anti-Gram-Positive Activity with Enhanced Potency against Gram-Negative Strains

Vancomycin functions by binding to lipid II, the penultimate bacterial cell wall building block used by both Gram-positive and Gram-negative species. However, vancomycin is generally only able to exert its antimicrobial effect against Gram-positive strains as it cannot pass the outer membrane (OM) of Gram-negative bacteria. To address this challenge, we here describe efforts to conjugate vancomycin to the OM disrupting polymyxin E nonapeptide (PMEN) to yield the hybrid “vancomyxins”. In designing these hybrid antibiotics, different spacers and conjugation sites were explored for connecting vancomycin and PMEN. The vancomyxins show improved activity against Gram-negative strains compared with the activity of vancomycin or vancomycin supplemented with PMEN separately. In addition, the vancomyxins maintain the antimicrobial effect of vancomycin against Gram-positive strains and, in some cases, show enhanced activity against vancomycin-resistant strains. The hybrid antibiotics described here have reduced nephrotoxicity when compared with clinically used polymyxin antibiotics. This study demonstrates that covalent conjugation to an OM disruptor contributes to sensitizing Gram-negative strains to vancomycin while retaining anti-Gram-positive activity.

Renoprotective Effects of Melatonin against Vancomycin-Related Acute Kidney Injury in Hospitalized Patients: a Retrospective Cohort Study

Vancomycin is associated with nephrotoxicity, and the mechanism may in part be related to oxidative stress. In vitro and preclinical studies suggest that melatonin supplementation decreases oxidative stress. The objective of this study was to evaluate concomitant use of melatonin and vancomycin and the incidence of acute kidney injury (AKI). We performed a retrospective cohort study at a large community medical center. All consecutive patients admitted to the medical center between January 2016 and September 2020 who received vancomycin therapy alone or concomitantly with melatonin as part of ordinary care were considered for inclusion. The primary endpoint was the development of AKI, defined as an absolute increase in serum creatinine of ≥0.3 mg/dl or a ≥50% increase in serum creatinine. All data were analyzed using descriptive statistics. A multivariable logistic regression was constructed to account for potential confounding variables. We identified a total of 303 adult patients meeting inclusion and exclusion criteria treated with vancomycin, 101 of which received melatonin concomitantly. Overall baseline characteristics were similar between the two groups except for the incidence of bacteremia/sepsis. After controlling for the vancomycin area under the curve, baseline creatinine clearance, and intensive care unit admission in a multivariable logistic regression analysis, melatonin use was associated with a 63% decrease in AKI (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.14 to 0.96; P = 0.041). Melatonin use was associated with a significant reduction in vancomycin-related AKI. Although this was a retrospective study with a small sample size, given the magnitude of the difference seen, further large prospective studies are warranted.

Early Life Antibiotics Influence In Vivo and In Vitro Mouse Intestinal Epithelium Maturation and Functioning

BACKGROUND & AIMS

The use of antibiotics (ABs) is a common practice during the first months of life. ABs can perturb the intestinal microbiota, indirectly influencing the intestinal epithelial cells (IECs), but can also directly affect IECs independent of the microbiota. Previous studies have focused mostly on the impact of AB treatment during adulthood. However, the difference between the adult and neonatal intestine warrants careful investigation of AB effects in early life.

METHODS

Neonatal mice were treated with a combination of amoxicillin, vancomycin, and metronidazole from postnatal day 10 to 20. Intestinal permeability and whole-intestine gene and protein expression were analyzed. IECs were sorted by a fluorescence-activated cell sorter and their genome-wide gene expression was analyzed. Mouse fetal intestinal organoids were treated with the same AB combination and their gene and protein expression and metabolic capacity were determined.

RESULTS

We found that in vivo treatment of neonatal mice led to decreased intestinal permeability and a reduced number of specialized vacuolated cells, characteristic of the neonatal period and necessary for absorption of milk macromolecules. In addition, the expression of genes typically present in the neonatal intestinal epithelium was lower, whereas the adult gene expression signature was higher. Moreover, we found altered epithelial defense and transepithelial-sensing capacity. In vitro treatment of intestinal fetal organoids with AB showed that part of the consequences observed in vivo is a result of the direct action of the ABs on IECs. Lastly, ABs reduced the metabolic capacity of intestinal fetal organoids.

CONCLUSIONS

Our results show that early life AB treatment induces direct and indirect effects on IECs, influencing their maturation and functioning.

Outcomes and Nephrotoxicity Associated with Vancomycin Treatment in Patients 80 Years and Older

Purpose

This retrospective observational study investigated the efficacy and safety of vancomycin to treat patients aged 80 years and older. In particular, the associations between vancomycin trough concentration (VTC) and treatment outcomes or nephrotoxicity were explored.

Patients and Methods

Patients aged ≥80 years had received ≥3 vancomycin treatments and ≥1 detection of VTC. Treatment outcomes were defined as success or failure. Nephrotoxicity was considered an increase in serum creatinine ≥ 44.2 mmol/L, or 50% above baseline, for ≥2 consecutive days. Univariate and multivariate analyses were performed to identify risk factors for treatment failure and nephrotoxicity.

Results

Of 349 patients, 120 (34.4%) experienced treatment failure. For patients with VTCs at <10, 10–15, 15–20, and ≥20 µg/mL, the clinical response rates were, respectively, 77.8, 77.0, 80.5, and 61.0%; the 30-day mortality rates were 2.8, 15.0, 15.3, and 37.8%; and the rates of persistent bacteremia were 16.7, 12.4, 11.9, and 11.0%. The multivariate analysis indicated that blood urea nitrogen ≥11 g/dL and heart failure were independently associated with treatment failure; but not VTC (P = 0.004, 0.016, 0.828, respectively). During vancomycin treatment, 42 (12.0%) patients experienced nephrotoxicity with recovery time 7.5 ± 4.5 days. Fewer than half of patients with nephrotoxicity recovered after suspending vancomycin application. The variables found independently associated with increased nephrotoxicity were: VTC ≥15 µg/mL; treatment duration ≥15 d; and concomitant aminoglycosides administration (P = 0.024, 0.035, 0.029).

Conclusion

In patients aged 80 years and older, elevated VTC level was not associated with favorable treatment outcomes. Patients with VTC ≥20 µg/mL appear to suggest a worsened prognosis compared with lower VTCs. The risk of nephrotoxicity increases with elevated VTC, longer treatment time, and concomitant aminoglycoside administration.

Current Paradigms of Combination therapy in Methicillin-Resistant Staphylococcus aureus (MRSA) Bacteremia: Does it Work, Which Combination and For Which Patients?

The last several years have seen an emergence of literature documenting the utility of combination antimicrobial therapy, particularly in the salvage of refractory MRSA bacteremia. Recent clinical data are shaping conundrums of which regimens may be more beneficial, which can be potentially harmful, and which subset of patients stand to benefit from more aggressive treatment regimens than called for by current standards. In addition, the incorporation of combination therapy for MRSA bacteremia should be accompanied by the reminder that antimicrobial therapy does not need to be uniform for the entire duration, with an early intensive phase in high inoculum infections (e.g. with combination therapy), followed by a consolidation phase (i.e. monotherapy). This review and perspective consolidates the recent data on this subject and directs future goals in filling the knowledge gaps to methodically move forward towards improving patient outcomes.

Vancomycin-Associated Tubular Casts and Vancomycin Nephrotoxicity

Introduction

Vancomycin nephrotoxicity is frequent and may be due to drug-induced acute tubular necrosis (ATN) or tubulointerstitial nephritis (TIN). Vancomycin-associated tubular cast (VTC) was recently described and may represent a novel cause of vancomycin nephrotoxicity. However, much is still unknown about VTC.

Materials and Methods

Thirty-seven kidney biopsy specimens from patients who were treated with vancomycin and developed acute kidney injury (AKI) were found among a total of 4673 biopsy samples between 2010 and 2019. These biopsy specimens were subjected to light microscopy, immunofluorescence, electron microscopy, and immunolocalization for vancomycin, uromodulin, myoglobin, tubular segment–specific markers, and examined for VTCs. The findings were correlated with the clinical course.

Results

VTCs displayed precipitated vancomycin casts in a background of uromodulin; the casts were limited to the distal tubules, and always associated with a background of more diffuse renal injury (ATN or TIN). The diagnosis of vancomycin nephrotoxicity was made in in 28 of 37 patients. VTC was noted in 25 of 28 biopsy samples from patients diagnosed with vancomycin nephrotoxicity and in one of nine biopsy samples from patients without this diagnosis. Vancomycin nephrotoxicity was diagnosed in 25 of 26 patients whose biopsy specimens showed VTC, but in only 3 of 11 patients without VTC in the biopsy samples.

Conclusions

VTC displays a characteristic morphologic profile amenable to ready recognition in biopsy specimens. It results from coprecipitation of vancomycin and uromodulin. It facilitates the biopsy diagnosis of vancomycin nephrotoxicity. It may have a nephrotoxic effect superimposing on and independent from the ATN or interstitial nephritis in the pathogenesis of vancomycin nephrotoxicity.

The efficiency of pomegranate (Punica granatum) peel ethanolic extract in attenuating the vancomycin-triggered liver and kidney tissues injury in rats

This study evaluated the potential of Punica granatum peel ethanol extract (PPEE) in attenuating the liver and kidney tissue injury induced by vancomycin (VM) treatment in rats. Fifty rats were distributed equally into five groups: control group, PPEE-administered group (100 mg/kg BW/day for 2 weeks; orally), VM-treated group (443.6 mg/kg BW, every alternate day for 2 weeks; intraperitoneally), pre-treated group, and concomitant-treated group. The biochemical response and the histopathology of the hepatic and renal tissue of the treated animals were assessed. The results showed that VM treatment induced substantial hepatotoxicity and nephrotoxicity, evidenced by a significant elevation in tissue injury and lipid oxidative (malondialdehyde) and inflammatory response (C-reactive protein) biomarkers, with lowered antioxidants and protein levels. Additionally, VM treatment induced various morphological, cytotoxic, vascular, and inflammatory perturbations as well as upregulation in the immune-expression of Caspase-3 and downregulation of BCL-2. Moreover, PPEE co-treatment was found to reduce the VM-induced toxicity by protecting the tissue against reactive oxygen species (ROS)-mediated oxidative damage, and inflammation as well as hinder the apoptotic cell death by modulating the expression of apoptosis-related proteins. Thus, we conclude that the PPEE administration showed more restoring efficacy when administered prior to VM medication.

The Role of Mitochondria in Drug-Induced Kidney Injury

The kidneys utilize roughly 10% of the body’s oxygen supply to produce the energy required for accomplishing their primary function: the regulation of body fluid composition through secreting, filtering, and reabsorbing metabolites and nutrients. To ensure an adequate ATP supply, the kidneys are particularly enriched in mitochondria, having the second highest mitochondrial content and thus oxygen consumption of our body. The bulk of the ATP generated in the kidneys is consumed to move solutes toward (reabsorption) or from (secretion) the peritubular capillaries through the concerted action of an array of ATP-binding cassette (ABC) pumps and transporters. ABC pumps function upon direct ATP hydrolysis. Transporters are driven by the ion electrochemical gradients and the membrane potential generated by the asymmetric transport of ions across the plasma membrane mediated by the ATPase pumps. Some of these transporters, namely the polyspecific organic anion transporters (OATs), the organic anion transporting polypeptides (OATPs), and the organic cation transporters (OCTs) are highly expressed on the proximal tubular cell membranes and happen to also transport drugs whose levels in the proximal tubular cells can rapidly rise, thereby damaging the mitochondria and resulting in cell death and kidney injury. Drug-induced kidney injury (DIKI) is a growing public health concern and a major cause of drug attrition in drug development and post-marketing approval. As part of the article collection “Mitochondria in Renal Health and Disease,” here, we provide a critical overview of the main molecular mechanisms underlying the mitochondrial damage caused by drugs inducing nephrotoxicity.

Acute Kidney Injury in Septic Patients Treated by Selected Nephrotoxic Antibiotic Agents-Pathophysiology and Biomarkers-A Review

Acute kidney injury is a common complication in critically ill patients with sepsis and/or septic shock. Further, some essential antimicrobial treatment drugs are themselves nephrotoxic. For this reason, timely diagnosis and adequate therapeutic management are paramount. Of potential acute kidney injury (AKI) biomarkers, non-protein-coding RNAs are a subject of ongoing research. This review covers the pathophysiology of vancomycin and gentamicin nephrotoxicity in particular, septic AKI and the microRNAs involved in the pathophysiology of both syndromes. PubMED, UptoDate, MEDLINE and Cochrane databases were searched, using the terms: biomarkers, acute kidney injury, antibiotic nephrotoxicity, sepsis, miRNA and nephrotoxicity. A comprehensive review describing pathophysiology and potential biomarkers of septic and toxic acute kidney injury in septic patients was conducted. In addition, five miRNAs: miR-15a-5p, miR-192-5p, miR-155-5p, miR-486-5p and miR-423-5p specific to septic and toxic acute kidney injury in septic patients, treated by nephrotoxic antibiotic agents (vancomycin and gentamicin) were identified. However, while these are at the stage of clinical testing, preclinical and clinical trials are needed before they can be considered useful biomarkers or therapeutic targets of AKI in the context of antibiotic nephrotoxicity or septic injury.

Cilastatin as a protective agent against drug-induced nephrotoxicity: a literature review

INTRODUCTION

Cilastatin, a dehydropeptidase I inhibitor, has been used alongside imipenem, a broad spectrum antibiotic, in order to reduce its renal metabolism, consequently increasing its urinary recovery and effectiveness for many years. However, this measure could be useful in preventing imipenem-induced renal damage and decreasing the number of nephrotoxicity reports with imipenem. In this review, the authors gathered all available studies focusing on cilastatin use as a nephroprotective agent, beside well-known nephrotoxic medications like vancomycin, cisplatin, cyclosporine, or tacrolimus.

AREAS COVERED

PubMed, Scopus, Google Scholar, and Medline databases were searched using key words like 'cilastatin,' 'nephroprotective,' 'nephroprotection,' 'vancomycin,' 'nephrotoxicity,' 'cisplatin,' 'cyclosporine,' 'tacrolimus,' and 'prevention' with varying combinations. All relevant animal and human studies up to the date of publication were included.

EXPERT OPINION

It seems that cilastatin could potentially be effective against drug-induced nephrotoxicity via mechanisms such as reducing reactive oxygen species (ROS) production, apoptosis, P-glycoprotein suppression, and morphological changes of renal cells. Nearly all the in vitro, in vivo and human studies have supported this hypothesis. Though since cilastatin protective effect has not extensively been researched in humans, its efficacy and widespread use with other nephrotoxic agents is yet to be defined in large well-designed human studies.

Bright and dark sides of exercise effects on biological responses such as energy metabolism and renal function in rats with renal failure and fructose-induced glucose intolerance

In the present study, we investigated the beneficial and risky effects of exercise intended to prevent or treat lifestyle-related diseases on insulin sensitivity, lactic acid utilization, lipid metabolism, hepatic and renal oxidative stress, hepatic selenoprotein P and renal function in obese and glucose-intolerant rats with renal failure. We fed normal rats a 20% casein diet while the glucose-intolerant, obese rats received a high-fructose diet, and after then rats received single injection of vancomycin at a dose of 400 mg/kg for constructing the duplicative state of renal failure and diabetes mellitus. They were forced to run for 1 h/day, 6 days/week, for 10 weeks. Exercise reduced visceral fat and ameliorated insulin sensitivity in the high-fructose group, improved lactic acid usage efficiency, however, increased hepatic oxidative stress and complicated renal dysfunction in the normal and high-fructose fed groups with renal failure. Additionally, exercise upregulated hepatic selenoprotein P expression and enhanced renal antioxidative system in both groups. It is concluded that strictly controlled exercise conditions must be adapted to patient health states especially in view of kidney protection, and supplemental therapy is also recommended in parallel with exercise, using nutrients and vitamins for kidney protection.

Liposomal delivery of antibiotic loaded nucleic acid nanogels with enhanced drug loading and synergistic anti-inflammatory activity against S. aureus intracellular infections

The persistence of Staphylococcus aureus has been accredited to its ability to escape immune response via host cell invasion. Despite the efficacy of many antibiotics against S. aureus, the high extracellular concentrations of conventional antibiotics required for bactericidal activity is limited by their low cellular accumulation and poor intracellular retention. While nanocarriers have received tremendous attention for antibiotic delivery against persistent pathogens, they suffer daunting challenges such as low drug loading, poor retention and untimely release of hydrophilic cargos. Here, a hybrid system (Van_DNL) is fabricated wherein nucleic acid nanogels are caged within a liposomal vesicle for antibiotic delivery. The central principle of this approach relies on exploiting non-covalent electrostatic interactions between cationic cargos and polyanionic DNA to immobilize antibiotics and enable precise temporal release against intracellular S. aureus. In vitro characterization of Van_DNL revealed a stable homogenous formulation with circular morphology and enhanced vancomycin loading efficiency. The hybrid system significantly sustained the release of vancomycin over 24 h compared to liposomal or nanogel controls. Under enzymatic conditions relevant to S. aureus infections, lipase triggered release of vancomycin was observed from the hybrid. While using Van_DNL to treat S. aureus infected macrophages, a dose dependent reduction in intracellular bacterial load was observed over 24 h and exposure to Van_DNL for 48 h caused negligible cellular toxicity. Pre-treatment of macrophages with the antimicrobial hybrid resulted in a strong anti-inflammatory activity in synergy with vancomycin following endotoxin stimulation. Conceptually, these findings highlight these hybrids as a unique and universal platform for synergistic antimicrobial and anti-inflammatory therapy against persistent infections.

Vancomycin-Induced Kidney Injury: Animal Models of Toxicodynamics, Mechanisms of Injury, Human Translation, and Potential Strategies for Prevention

Vancomycin is a recommended therapy in multiple national guidelines. Despite the common use, there is a poor understanding of the mechanistic drivers and potential modifiers of vancomycin-mediated kidney injury. In this review, historic and contemporary rates of vancomycin-induced kidney injury (VIKI) are described, and toxicodynamic models and mechanisms of toxicity from preclinical studies are reviewed. Aside from known clinical covariates that worsen VIKI, preclinical models have demonstrated that various factors impact VIKI, including dose, route of administration, and thresholds for pharmacokinetic parameters. The degree of acute kidney injury (AKI) is greatest with the intravenous route and higher doses that produce larger maximal concentrations and areas under the concentration curve. Troughs (i.e., minimum concentrations) have less of an impact. Mechanistically, preclinical studies have identified that VIKI is a result of drug accumulation in proximal tubule cells, which triggers cellular oxidative stress and apoptosis. Yet, there are several gaps in the knowledge that may represent viable targets to make vancomycin therapy less toxic. Potential strategies include prolonging infusions and lowering maximal concentrations, administration of antioxidants, administering agents that decrease cellular accumulation, and reformulating vancomycin to alter the renal clearance mechanism. Based on preclinical models and mechanisms of toxicity, we propose potential strategies to lessen VIKI.

Taurine attenuates isoproterenol-induced H9c2 cardiomyocytes hypertrophy by improving antioxidative ability and inhibiting calpain-1-mediated apoptosis

Pathological cardiac hypertrophy is ultimately accompanied by cardiomyocyte apoptosis. Apoptosis mainly related to calpain-1-mediated apoptotic pathways. Studies had proved that taurine can maintain heart health through antioxidation and antiapoptotic functions, but the effect of taurine on cardiac hypertrophy is still unclear. This study aimed to determine whether taurine could inhibit calpain-1-mediated mitochondria-dependent apoptotic pathways in isoproterenol (ISO)-induced hypertrophic cardiomyocytes. We found that taurine could inhibit the increase in cell surface area and reduce the protein expression levels of the hypertrophic markers atrial natriuretic peptide, brain natriuretic polypeptide, and β-myosin heavy chain. Taurine also reduced ROS, intracellular Ca²⁺ overload and mitochondrial membrane potential. Moreover, taurine inhibited cardiomyocyte apoptosis by decreasing the protein expression of calpain-1, Bax, t-Bid, cytosolic cytochrome c, Apaf-1, cleaved caspase-9 and cleaved caspase-3 and by enhancing calpastatin and Bcl-2 protein expression. Calpain-1 small interfering RNA transfection results showed similar antiapoptotic effects as the taurine prevention group. However, compared with the two treatments, taurine inhibited the expression of cleaved caspase-9 more significantly. Therefore, we believe that taurine prevents ISO-induced H9c2 cardiomyocyte hypertrophy by inhibiting oxidative stress, intracellular Ca²⁺ overload, the calpain-1-mediated mitochondria-dependent apoptotic pathway and cleaved caspase-9 levels.

High-Dose Vitamin C Preadministration Reduces Vancomycin-Associated Nephrotoxicity in Mice

Vancomycin is recommended for treating severe infections caused by Gram-positive cocci, including methicillin-resistant Staphylococcus aureus. However, renal damage often occurs as a side effect because vancomycin is mainly excreted via the kidneys. The mechanism of vancomycin-associated nephrotoxicity is thought to involve the elevation of oxidative stress in the kidneys. Vitamin C (VC) has strong antioxidant properties; therefore, we evaluated the effect of high-dose VC preadministration on vancomycin-associated nephrotoxicity. Vancomycin was intraperitoneally injected into mice once daily for 7 d. Additionally, high-dose VC was intraperitoneally injected into mice at 30 min before vancomycin administration for 7 d. The plasma creatinine and urea nitrogen levels were increased by vancomycin treatment; however, high-dose VC preadministration suppressed the increase in these levels. Histological examination also revealed that high-dose VC preadministration reduced the characteristics of vancomycin-associated nephrotoxicity, such as dilated renal tubules with casts, the dilation of renal proximal tubules, and tubular epithelial desquamation. Furthermore, high-dose VC preadministration reduced the appearance of apoptotic cells presumably derived from the epithelial cells in the dilated proximal tubules. Thus, intraperitoneally injected high-dose VC preadministration reduced vancomycin-associated nephrotoxicity in mice. These novel findings may indicate that vancomycin-associated nephrotoxicity in humans may be reduced by high-dose VC preadministration.

New insights into the vancomycin-induced nephrotoxicity using in vitro metabolomics combined with physiologically based pharmacokinetic modeling

Vancomycin is a first-line treatment for invasive infections caused by multidrug-resistant gram-positive bacteria. However, vancomycin-induced nephrotoxicity is an increasing burden, particularly in patients with complex life-threatening conditions. Vancomycin-induced nephrotoxicity associated with clinically relevant exposure on the target site has not been well defined. This study aimed to acquire the concentration of vancomycin in the renal tubules and kidneys in humans using physiologically based pharmacokinetic (PBPK) modeling and simulation. Based upon the exposure of vancomycin in the renal tubule, the toxicity of vancomycin in human renal proximal tubular epithelial cells was examined with the XTT assay and in vitro metabolomics analysis. A rat PBPK model predicting plasma and kidney concentration-time profiles of vancomycin matched the observed behavior after a single administration of 10 mg/kg. The concentration of vancomycin in renal tubules was about 40-50 times higher than that in plasma. The human PBPK model transferred from the rat model predicted renal tubule concentrations of vancomycin as 316.1-2136.6 μg/mL at 500 mg every 6 hours, and 199.0-3932.5 μg/mL at 1000 mg every 12 hours. Vancomycin showed significant nephrotoxicity at 4 mg/mL in XTT assessment. In total, 11 lysophosphatidylcholines and one lysophosphatidylethanolamine were identified by metabolomics analysis. The concentration-dependent increase was evident in the release of lysophospholipids after vancomycin treatment (0.125-4 mg/mL) for 24 hours. Our study revealed the relationship between the exposure of vancomycin in the kidney and toxicity of vancomycin at clinically relevant concentrations achieved from a mechanical PBPK model. A series of lysophospholipids as potential metabolic markers of renal toxicity were identified.

Acute toxic kidney injury

Substances toxic to the kidney are legion in the modern world. The sheer number and variety, their mutual interactions and, metabolism within the body are a challenge to research. Moreover, the kidney is especially prone to injury owing to its physiology. Acute kidney injury (AKI) induced by poisonous or primarily nephrotoxic substances, may be community acquired with ingestion or inhalation or nosocomial. Many nephrotoxic plants, animal poisons, medications, chemicals and illicit drugs can induce AKI by varying pathophysiological pathways. Moreover, the epidemiology of toxic AKI varies depending on country, regions within countries, socioeconomic status and health care facilities. In this review, we have selected nephrotoxic insults due to medication, plants, animal including snake venom toxicity, environmental, (agri)chemicals and also illicit drugs. We conclude with a section on diagnosis, clinical presentation and management of poisoning accompanied by various organ dysfunction and AKI.

ATP-binding cassette A1 deficiency causes cardiolipin-driven mitochondrial dysfunction in podocytes

Fibroblasts from patients with Tangier disease carrying ATP-binding cassette A1 (ABCA1) loss-of-function mutations are characterized by cardiolipin accumulation, a mitochondrial-specific phospholipid. Suppression of ABCA1 expression occurs in glomeruli from patients with diabetic kidney disease (DKD) and in human podocytes exposed to DKD sera collected prior to the development of DKD. We demonstrated that siRNA ABCA1 knockdown in podocytes led to reduced oxygen consumption capabilities associated with alterations in the oxidative phosphorylation (OXPHOS) complexes and with cardiolipin accumulation. Podocyte-specific deletion of Abca1 (Abca1fl/fl) rendered mice susceptible to DKD, and pharmacological induction of ABCA1 improved established DKD. This was not mediated by free cholesterol, as genetic deletion of sterol-o-acyltransferase-1 (SOAT1) in Abca1fl/fl mice was sufficient to cause free cholesterol accumulation but did not cause glomerular injury. Instead, cardiolipin mediates ABCA1-dependent susceptibility to podocyte injury, as inhibition of cardiolipin peroxidation with elamipretide improved DKD in vivo and prevented ABCA1-dependent podocyte injury in vitro and in vivo. Collectively, we describe a pathway definitively linking ABCA1 deficiency to cardiolipin-driven mitochondrial dysfunction. We demonstrated that this pathway is relevant to DKD and that ABCA1 inducers or inhibitors of cardiolipin peroxidation may each represent therapeutic strategies for the treatment of established DKD.

Rutin Attenuates Vancomycin-Induced Nephrotoxicity by Ameliorating Oxidative Stress, Apoptosis, and Inflammation in Rats

Nephrotoxicity is the major limiting factor for the clinical use of vancomycin (VCM) for treatment of serious infections caused by multiresistant Gram-positive bacteria. This study investigated the renal protective activity of rutin in a rat model of VCM-induced kidney injury in male Wistar rats. VCM administered intraperitoneally at 200 mg/kg twice daily for 7 successive days resulted in significant elevation of blood urea nitrogen and creatinine, as well as urinary N-acetyl-β-D-glucosaminidase. Coadministration of VCM with oral rutin at 150 mg/kg significantly reduced these markers of kidney damage. Rutin also significantly attenuated VCM-induced oxidative stress, inflammatory cell infiltration, apoptosis, and decreased interleukin-1β and tumor necrosis factor alpha levels (all P < 0.05 or 0.01) in kidneys. Renal recovery from VCM injury was achieved by rutin through increases in Nrf2 and HO-1 and a decrease in NF-κB expression. Our results demonstrated a protective effect of rutin on VCM-induced kidney injury through suppression of oxidative stress, apoptosis, and downregulation of the inflammatory response. This study highlights a role for oral rutin as an effective intervention to ameliorate nephrotoxicity in patients undergoing VCM therapy.

Age-dependent changes in vancomycin-induced nephrotoxicity in mice

Vancomycin hydrochloride (VCM) is a glycopeptide antibiotic that is commonly used to eradicate methicillin-resistant gram-positive cocci, despite its nephrotoxic side effects. Elderly people are particularly susceptible to developing VCM-induced nephrotoxicity. However, the precise mechanism by which VCM induces nephrotoxicity in elderly people is not completely understood. Therefore, we investigated VCM-induced nephrotoxicity in mice of different ages. VCM was injected intraperitoneally into mice at 1, 3, 6, 12, and 24 months of age at a dosage of 400 mg/kg body weight for 3 and 14 days. Twenty-four hours after the last injection, we examined plasma creatinine levels and histopathological alterations in the kidneys. VCM administration increased plasma creatinine levels, and these values gradually increased to higher levels with aging. The histological examination revealed renal tubular degeneration, such as brush-border atrophy, apoptosis/necrosis of the tubular epithelium, and epithelial desquamation, that gradually became more severe with aging. Furthermore, immunohistochemical staining with anti-CD10 and anti-single-stranded DNA antibodies revealed damaged renal proximal tubules with marked dilatation, as well as numerous apoptotic cells, and these features increased in severity in 12- and 24-month-old mice receiving VCM. Based on these results, aged mice were highly susceptible to kidney damage induced by VCM administration. In addition, proximal tubular epithelial cells likely underwent apoptosis after the administration of VCM. This report is the first to document VCM-induced nephrotoxicity in mice of different ages. Thus, this mouse model could be useful for understanding the mechanisms of VCM-induced nephrotoxicity in the elderly.

Icariin modulates mitochondrial function and apoptosis in high glucose-induced glomerular podocytes through G protein-coupled estrogen receptors

Podocyte apoptosis in glomerular lesions has been found to have a dominant role in the progression of diabetic nephropathy. The present research aimed to explore the beneficial effect of icariin on diabetic podocytes by interfering in the process of apoptosis. Podocyte apoptosis was significantly exacerbated after high glucose treatment, with the level of reactive oxygen species (ROS) increasing simultaneously. Here, we demonstrated that icariin, which is a G protein-coupled estrogen receptor 1 (GPER) agonist, inhibited podocyte apoptosis by reducing ROS, maintaining the integrity of mitochondrial membranes. Moreover, the stabilization of mitochondria by icariin was reversed when GPER was knocked down in podocytes. Meanwhile, icariin inhibited the caspase cascade in podocyte apoptosis by promoting Bcl-2 expression and mitochondrial translocation. The above findings at least partly elucidated the mechanism by which icariin stabilized podocytes by inducing the mitochondrial Bcl-2 translocation and therefore preventing downstream apoptosis.

Modulation of quantum dots and clearance of Helicobacter pylori with synergy of cell autophagy

Helicobacter pylori (Hp) is one type of Gram-negative pathogenic bacterium that colonizes and causes a wide range of gastric diseases. Once Hp penetrates into cells, the currently recognized triple or quadruple therapy often loses effectiveness. Recent evidence suggests that autophagy is closely associated with Hp infection, and can play an important role in the eradication of Hp. More importantly, certain types of quantum dots (QDs) can induce and modulate cellular autophagy, and can be developed into conjugates making QDs potential candidates as new anti-Hp agents.

Retracted Article: PVT1 knockdown alleviates vancomycin-induced acute kidney injury by targeting miR-124 via inactivation of NF-κB signaling

Acute kidney injury (AKI) is a serious threat for human health and life. High dose of vancomycin (VAN) can give rise to AKI. The roles and molecular basis of long noncoding RNA plasmacytoma variant translocation 1 (PVT1) in VAN-induced AKI have been poorly defined till now. Protein levels of p65, phosphorylated p65 (p-p65), NF-κB inhibitor alpha (IκBα), phosphorylated IκBα (p-IκBα), Bcl-2 and Bax were measured by western blot assay. RNA levels of PVT1 and microRNA-124 (miR-124) were determined by RT-qPCR assay. HK-2 cell apoptosis was detected by an Annexin V-FITC apoptosis detection assay. Kidney functions were assessed by blood urea nitrogen (BUN) level, serum creatinine (Scr) level, histopathologic analysis, and TUNEL assay. Bioinformatical analysis, luciferase reporter assay, RIP and RNA pull down assays were performed to explore whether PVT1 could interact with miR-124. PVT1 was highly expressed in VAN-induced AKI models. Functional analysis revealed that PVT1 knockdown ameliorated VAN-induced AKI in vivo. Further exploration manifested that PVT1 directly interacted with miR-124. Moreover, the silencing of PVT1 abated VAN-induced HK-2 cell apoptosis in vitro, while this effect was reversed by the miR-124 inhibitor. Also, VAN treatment resulted in the reduction of miR-124 expression and the activation of NF-κB signaling in HK-2 cells. The inhibition of NF-κB alleviated VAN-induced HK-2 cell apoptosis. PVT1 activated NF-κB signaling by targeting miR-124 in VAN-induced HK-2 cells. PVT1 knockdown lessened VAN-induced AKI by targeting miR-124 via inactivating the NF-κB signaling, elucidating the critical roles and molecular basis of PVT1 in VAN-induced AKI and highlighting the diagnostic and therapeutic values of PVT1 in AKI.

PVT1 was highly expressed in the kidneys of VAN-induced AKI mice.

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.

The Nephrotoxicity of Vancomycin

Vancomycin use is often associated with nephrotoxicity. It remains uncertain, however, to what extent vancomycin is directly responsible, as numerous potential risk factors for acute kidney injury frequently coexist. Herein, we critically examine available data in adult patients pertinent to this question. We review the pharmacokinetics/pharmacodynamics of vancomycin metabolism. Efficacy and safety data are discussed. The pathophysiology of vancomycin nephrotoxicity is considered. Risk factors for nephrotoxicity are enumerated, including the potential synergistic nephrotoxicity of vancomycin and piperacillin‐tazobactam. Suggestions for clinical practice and future research are given.