Difference in nephrotoxicity of vancomycin administered once daily and twice daily in rats

The preventive effect of Gastrodia elata Blume extract on vancomycin-induced acute kidney injury in rats

BACKGROUND

Gastrodia elata Blume (GEB), a traditional medicinal herb, has been reported to have pharmacological effect including protection against liver, neuron and kidney toxicity. However, explanation of its underlying mechanisms remains a great challenge. This study investigated the protective effects of GEB extract on vancomycin (VAN)-induced nephrotoxicity in rats and underlying mechanisms with emphasis on the anti-oxidative stress, anti-inflammation and anti-apoptosis. The male Sprague-Dawley rats were randomly divided three groups: control (CON) group, VAN group and GEB group with duration of 14 days.

RESULTS

The kidney weight and the serum levels of blood urea nitrogen and creatinine in the GEB group were lower than the VAN group. Histological analysis using hematoxylin & eosin and periodic acid Schiff staining revealed pathological changes of the VAN group. Immunohistochemical analysis revealed that the expression levels of N-acetyl-D-glucosaminidase, myeloperoxidase and tumor necrosis factor-alpha in the GEB group were decreased when compared with the VAN group. The number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells, phosphohistone and malondialdehyde levels were lower in the GEB group than VAN group. The levels of total glutathione in the GEB group were higher than the VAN group.

CONCLUSIONS

The findings of this study suggested that GEB extract prevents VAN-induced renal tissue damage through anti-oxidation, anti-inflammation and anti-apoptosis.

Patient safety outcomes for continuous infusion vancomycin as outpatient parenteral antimicrobial therapy

BACKGROUND

Administration of vancomycin as a continuous infusion has been associated with reduced nephrotoxicity. Given limited published experience with continuous infusion vancomycin in outpatient parenteral antimicrobial therapy (OPAT) programs, we reviewed outcomes from our center.

METHODS

This was a retrospective, single-center study of adult patients receiving vancomycin OPAT as continuous or intermittent infusion for an intended treatment duration of at least 7 days. The primary outcome was time to nephrotoxicity with continuous versus intermittent infusion vancomycin while on OPAT; additional outcomes included time to any vancomycin-associated adverse event, time to 60-day death or readmission, and time to 60-day emergency department encounter. Proportional hazards modeling was used to identify variables independently associated with outcomes, as well as assess the strength of association of continuous infusion with each outcome.

RESULTS

Four-hundred ninety-two patients were included: 118 treated with continuous and 374 with intermittent vancomycin infusion. Continuous infusion was not associated with lower rates of nephrotoxicity compared to intermittent infusion (adjusted hazard ratio (aHR) 0.72, 95% CI: 0.35-1.50). There were no advantages of continuous over intermittent infusion in the rates of any adverse event (aHR 0.93, 95% CI: 0.56-1.53), 60-day death or readmission (aHR 1.04, 95% CI: 0.68-1.61), or 60-day emergency department encounter (aHR 1.17, 95% CI: 0.68-1.99). Vancomycin area under the concentration-time curve (AUC) at discharge was the only modifiable factor identified that was independently associated with patient safety outcomes.

CONCLUSION

There was no appreciable benefit of continuous infusion vancomycin on outpatient safety outcomes. AUC-centered dosing approaches warrant further investigation as strategies to improve vancomycin safety in OPAT programs.

The Pharmacodynamic-Toxicodynamic Relationship of AUC and C max in Vancomycin-Induced Kidney Injury in an Animal Model

Vancomycin induces exposure-related acute kidney injury. However, the pharmacokinetic-toxicodynamic (PK-TD) relationship remains unclear. Sprague-Dawley rats received intravenous (i.v.) vancomycin doses of 300 mg/kg/day and 400 mg/kg/day, divided into once-, twice-, three-times-, or four-times-daily doses (i.e., QD, BID, TID, or QID) over 24 h. Up to 8 samples plus a terminal sample were drawn during the 24-h dosing period. Twenty-four-hour urine was collected and assayed for kidney injury molecule-1 (KIM-1). Vancomycin was quantified via liquid chromatography-tandem mass spectrometry (LC-MS/MS). Following terminal sampling, nephrectomy and histopathologic analyses were conducted. PK analyses were conducted using Pmetrics. PK exposures (i.e., area under the concentration-time curve from 0 to 24 h [AUC_0-24] and maximum concentration from 0 to 24 h [C _max0-24]) were calculated for each rat, and PK-TD relationships were discerned. A total of 53-rats generated PK-TD data. A 2-compartment model fit the data well (Bayesian observed versus predicted concentrations; R ² = 0.96). KIM-1 values were greater in QD and BID groups (P for QD versus TID, <0.002; P for QD versus QID, <0.004; P for BID versus TID, <0.002; and P for BID versus QID, <0.004). Exposure-response relationships were observed between KIM-1 versus C _max0-24 and AUC_0-24 (R ² = 0.7 and 0.68). Corrected Akaike's information criterion showed C _max0-24 as the most predictive PK-TD driver for vancomycin-induced kidney injury (VIKI) (-5.28 versus -1.95). While PK-TD indices are often intercorrelated, maximal concentrations and fewer doses (for the same total daily amount) resulted in increased VIKI in our rat model.

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.

Potential renoprotective effects of silymarin against vancomycin-induced nephrotoxicity in rats

Silymarin (SLY), a flavonoid complex isolated from the seeds of Silybum marianum (Asteraceae), has antioxidant, anti-apoptotic, anti-inflammatory, and anti-lipid peroxidative effects. Vancomycin (VA), used for treating serious infections, has been associated with nephrotoxicity, which limits its use. Therefore, this study aimed to investigate the potential renoprotective effects of SLY on VA-induced nephrotoxicity using renal, apoptotic (caspase-3, caspase-8, and caspase-9 enzyme activities), and oxidative stress [nitric oxide (NO) and malondialdehyde (MDA)] markers; serum blood urea nitrogen (BUN) and creatinine levels; and histopathological examination. A total of 49 male Wistar albino rats were used (n = 7): control [saline, intraperitoneally (i.p.)], dimethyl sulfoxide (i.p.), VA [400 mg/(kg-day), i.p.], SLY100 [100 mg/(kg-day), i.p.], VA + SLY50 [50 mg/(kg-day), i.p.], VA + SLY100 [100 mg/(kg-day), i.p.], and VA + SLY200 [200 mg/(kg-day), i.p.]. SLY was administered once daily for 8 days. One day after the first treatment of SLY, VA administration was started and continued for 7 days. The levels of serum creatinine and BUN were evaluated using ELISA, caspase enzyme activities and levels of MDA and NO in the kidney tissues were evaluated by the colorimetric methods. The serum BUN, creatinine, NO, MDA levels, and caspase activities were significantly higher in VA group than in control (p < 0.05). However, caspase activities were significantly lower in VA + SLY200 than in VA (p < 0.05). The MDA, serum BUN, and creatinine levels were significantly lower in VA + SLY (50, 100, and 200) groups than in VA group (p < 0.05). VA + SLY200 was found to be the most effective group based on the caspase activities; MDA, NO, serum BUN, creatinine levels; and histopathological findings.

Potential protective effects of naringenin against vancomycin-induced nephrotoxicity via reduction on apoptotic and oxidative stress markers in rats

Vancomycin (VCM), a glycopeptide antibiotic, is a drug widely used in severe infections. However, VCM induce notable nephrotoxic side effects. Naringenin (NAR) is a natural of flavonoid and are known as strongly antioxidant, nefroprotective, antiapoptotic, and anti-inflammatory. The purpose of this study was to determine the potential protective effects of NAR against VCM-induced nephrotoxicity by measuring apoptotic and oxidative stress markers and evaluating histopathological alterations in rats. For this purpose, we used male Wistar albino rats that divided into seven groups: (i) Control [saline, intraperitoneally (i.p.)], (ii) carboxymethyl cellulose (0.5% CMC, orally), (iii) VCM (400 mg/kg, i.p.), (iv) NAR100 (100 mg/kg, orally), (v) VCM + NAR25 (25 mg/kg, orally), (vi) VCM + NAR50 (50 mg/kg, orally), and (vii) VCM + NAR100 (100 mg/kg, orally) groups. VCM administration was started one day after the first treatment of NAR and continued across 7-day. Caspase-3, -8, and-9 activities and malondialdehyde (MDA) and nitric oxide (NO) levels were measured by colorimetric methods in the kidney tissues, creatinine, and blood urea nitrogen (BUN) levels were analyzed based on ELISA in serum. Caspase-3 and -8 activities, NO levels, serum creatinine and BUN levels were significantly higher in VCM group in comparison with VCM + NAR (25, 50, and 100) groups (p < 0.05). Caspase-9 activity and MDA were significantly higher in VCM group compared to VCM + NAR (25 and 50) groups (p < 0.05). Histopathological alterations in VCM group were significantly diminished by administration of NAR, especially NAR 25. In conclusion, NAR 25 and 50 mg have more potent protective effects on VCM-induced nephrotoxicity compared to NAR 100 mg.

High-Performance Liquid Chromatography Method for Rich Pharmacokinetic Sampling Schemes in Translational Rat Toxicity Models With Vancomycin

A translational need exists to understand and predict vancomycin‐induced kidney toxicity. We describe: (i) a vancomycin high‐performance liquid chromatography (HPLC) method for rat plasma and kidney tissue homogenate; (ii) a rat pharmacokinetic (PK) study to demonstrate utility; and (iii) a catheter retention study to enable future preclinical studies. Rat plasma and pup kidney tissue homogenate were analyzed via HPLC for vancomycin concentrations ranging from 3–75 and 15.1–75.5 μg/mL, respectively, using a Kinetex Biphenyl column and gradient elution of water with 0.1% formic acid: acetonitrile (70:30 v/v). Sprague‐Dawley rats (n = 10) receiving 150 mg/kg of vancomycin intraperitoneally had plasma sampled for PK. Finally, a catheter retention study was performed on polyurethane catheters to assess adsorption. Precision was <6.1% for all intra‐assay and interassay HPLC measurements, with >96.3% analyte recovery. A two‐compartment model fit the data well, facilitating PK exposure estimates. Finally, vancomycin was heterogeneously retained by polyurethane catheters.

Evaluation of Vancomycin Exposures Associated with Elevations in Novel Urinary Biomarkers of Acute Kidney Injury in Vancomycin-Treated Rats

Vancomycin has been associated with acute kidney injury (AKI). However, the pharmacokinetic/toxicodynamic relationship for AKI is not well defined. Allometrically scaled vancomycin exposures were used to assess the relationship between vancomycin exposure and AKI. Male Sprague-Dawley rats received clinical-grade vancomycin in normal saline (NS) as intraperitoneal (i.p.) injections for 24- to 72-h durations with doses ranging 0 to 200 mg/kg of body weight divided once or twice daily. Urine was collected over the protocol's final 24 h. Renal histopathology was qualitatively scored. Urinary biomarkers (e.g., cystatin C, clusterin, kidney injury molecule 1 [KIM-1], osteopontin, lipocalin 2/neutrophil gelatinase-associated lipocalin 2) were assayed using a Luminex xMAP system. Plasma vancomycin concentrations were assayed by high-performance liquid chromatography with UV detection. A three-compartment vancomycin pharmacokinetic model was fit to the data with the Pmetrics package for R. The exposure-response in the first 24 h was evaluated using Spearman's nonparametric correlation coefficient (rs) values for the area under the concentration-time curve during the first 24 h (AUC0-24), the maximum concentration in plasma during the first 24 h (Cmax0-24 ), and the lowest (minimum) concentration in plasma after the dose closest to 24 h (Cmin0-24 ). A total of 52 rats received vancomycin (n = 42) or NS (n = 10). The strongest exposure-response correlations were observed between AUC0-24 and Cmax0-24 and urinary AKI biomarkers. Exposure-response correlations (rs values) for AUC0-24, Cmax0-24 , and Cmin0-24 were 0.37, 0.39, and 0.22, respectively, for clusterin; 0.42, 0.45, and 0.26, respectively, for KIM-1; and 0.52, 0.55, and 0.42, respectively, for osteopontin. However, no differences in histopathological scores were observed. Optimal sampling times after administration of the i.p. dose were 0.25, 0.75, 2.75, and 8 h for the once-daily dosing schemes and 0.25, 1.25, 14.5, and 17.25 h for the twice-daily dosing schemes. Our observations suggest that AUC0-24 or Cmax0-24 correlates with increases in urinary AKI biomarkers.