Estimated glomerular filtration rate in observational and interventional studies in chronic kidney disease

Estimated glomerular filtration rate is considered the principal measure of kidney function and, together with albuminuria, is a relevant prognostic factor for the development of end-stage kidney disease. Due to the strong association between estimated glomerular filtration rate and clinical events, such as commencement of dialysis, cardiovascular outcomes and all-cause death, estimated glomerular filtration rate is crucial for clinical decision-making in terms of scheduling follow-up and pharmacological interventions, and planning renal replacement therapies in advanced chronic kidney disease. In this review we discuss the available methods for measuring glomerular filtration rate and for estimating it through mathematical equations developed over the last few decades. We summarize the prognostic association of different percentages of estimated glomerular filtration rate decline and the main clinical outcomes, and how treatments modify estimated glomerular filtration rate decline and the risk of future endpoints. We also examine the role of pre-clinical trial slope and that of estimated glomerular filtration rate as a useful biomarker when evaluating patients for inclusion into both observational and interventional studies.

Daphnetin ameliorated GM-induced renal injury through the suppression of oxidative stress and apoptosis in mice

Gentamicin (GM), an aminoglycoside antibiotic, is one of the most effective drugs used in the treatment of various types of bacterial infections, but the major adverse effect and drug-induced nephrotoxicity of GM limit its clinical applications. Daphnetin (Daph) is a natural coumarin derivative that is clinically used to treat rheumatoid arthritis and coagulopathy and exhibits antioxidant effects. However, the effect of Daph on GM-induced nephrotoxicity has not yet been elucidated. This study investigated Daph-mediated protection against GM-induced nephrotoxicity in mice and explored the underlying mechanisms of GM-induced renal dysfunction in mice. We found that Daph treatment significantly reduced GM-induced nephrotoxicity mainly by ameliorating renal injury in mice and attenuating cell damage in vitro. Mechanistically, we found that Daph upregulated the expression level of Nrf2 and its regulated antioxidant enzymes HO-1, NQO1, GCLC and GCLM in vivo and in vitro. GM upregulated the expression levels of NOX4, cleaved Caspase-3 and p53 and the BAX/BCL2 ratio in vivo to stimulate oxidative stress and apoptosis. However, Daph treatment significantly improved the oxidative stress and apoptosis caused by GM, thereby exerting antioxidative and antiapoptotic effects. Our study was the first to suggest that the natural product Daph protects against GM-induced nephrotoxicity through the activation of Nrf2 which regulates oxidative stress and apoptosis. The pharmacological activation of Nrf2 may be useful as a novel therapy to prevent renal injury.

Risk of Prolonged Corrected QT Interval With Amisulpride Therapy for Renal Function Management in Patients With Schizophrenia

BACKGROUND

Amisulpride (AMI) is a popular antipsychotic drug prescribed for the management of schizophrenia. However, patients may experience prolonged corrected QT (QTc) interval. We therefore aimed to assess the risk factors for QTc prolongation during AMI therapy in patients with schizophrenia.

METHODS

This study retrospectively enrolled 271 patients with schizophrenia. Continuous variables were analyzed with a t test or analysis of variance, and categorical variables were analyzed with a χ test. Patients with and without QTc prolongation were compared using a backward stepwise logistic regression analysis to identify the important variables.

RESULTS

Comedication of AMI with clozapine (odds ratio, 3.5 [95% confidence interval, 1.3-9.7]) and decreased renal function (mildly decrease, 3.4 [1.2-10.1]; mild to moderately decreased, 4.8 [1.3-17.3]; moderately decreased, 13.6 [2.0-90.6]) were identified as the independent risk factors of QTc prolongation. The dose-normalized plasma concentration of AMI (plasma concentration per dose) was significantly higher in the QTc prolongation group (z = -1.735, P = 0.015) and renal dysfunction group (F = 16.002, P < 0.001).

CONCLUSIONS

Renal function should be monitored in patients prescribed with AMI, particularly in those taking clozapine. Plasma concentration per dose values can be considered as a risk factor of QTc interval prolongation. The founding help clinicians to analyze the risk of QTc prolongation before prescribing AMI and to monitor QTc prolongation during AMI therapy.

Comparison of the Cockcroft-Gault, MDRD and CKD-EPI equations for estimating ganciclovir clearance

AIMS

Accurately estimating kidney function is essential for the safe administration of renally cleared drugs such as ganciclovir. Current practice recommends adjusting renally eliminated drugs according to the Cockcroft-Gault equation. There are no data on the utility of the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in ganciclovir dosing. To evaluate which renal function equation best predicts ganciclovir clearance.

METHODS

The performance of the Cockcroft-Gault equation, isotope dilution mass spectrometry (IDMS)-traceable 4-variable MDRD study (MDRD4-IDMS) equation and CKD-EPI equation in determining ganciclovir clearance were assessed retrospectively in patients treated with ganciclovir from 2004-2015. The MDRD4-IDMS and CKD-EPI equations adjusted to individual body surface area (MDRD4-IDMS·BSA and CKD-EPI·BSA, respectively) were also evaluated. Patients with intravenous ganciclovir peak and trough concentrations in their medical records were included in the study. Ganciclovir clearance was calculated from serum concentrations using a one-compartment model. The five equations were compared based on their predictive ability, the coefficient of determination, through a linear regression analysis. The results were validated in a group of patients.

RESULTS

One hundred patients were included in the final analysis. Seventy-four patients were analysed in the learning group and 26 in the validation group. The coefficient of determination was 0.281 for Cockcroft-Gault, 0.301 for CKD-EPI·BSA, 0.308 for MDRD4-IDMS·BSA, 0.324 for MDRD4-IDMS and 0.360 for CKD-EPI. Subgroup analysis also showed that CKD-EPI is a better predictor of ganciclovir clearance. Analysis of the validation group confirmed these results.

CONCLUSIONS

The CKD-EPI equation correlates better with ganciclovir clearance than the Cockcroft-Gault and MDRD4-IDMS equations, even the clinical difference between the equations is scarce.

Preventive effect of fermented black ginseng against cisplatin-induced nephrotoxicity in rats

Background

Fermented black ginseng (FBG) is processed ginseng by the repeated heat treatment and fermentation of raw ginseng. The protective effect and mechanism of FBG on cisplatin-induced nephrotoxicity was investigated to evaluate its therapeutic potential.

Methods

The free radical scavenging activity of FBG was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH). In addition, the protective effect against cisplatin-induced renal damage was tested in rats. FBG was orally administered every day at a dose of 150 mg/kg body weight for 10 d, and a single dose of cisplatin was administered intraperitoneally (7.5 mg/kg body weight) with 0.9% saline on the 4^th d.

Results

The DPPH radical-scavenging activity of FBG (IC₅₀ = 384 μg/mL) was stronger than that of raw ginseng. The improved DPPH radical-scavenging activity was mediated by the generation phenolic compounds. The decreased cell viability by cisplatin was recovered significantly after treatment with FBG in a dose-dependent manner. Then, the protective effect of FBG on cisplatin-induced oxidative renal damage was investigated in rats. The decreased creatinine clearance levels, which are a reliable marker for renal dysfunction in cisplatin-treated rats, were reduced to the normal level after the administration of FBG. Moreover, FBG showed protective effects against cisplatin-induced oxidative renal damage in rats through the inhibition of NF-κB/p65, COX-2, and caspase-3 activation.

Conclusion

These results collectively show that the therapeutic evidence for FBG ameliorates the nephrotoxicity via regulating oxidative stress, inflammation, and apoptosis.

Emerging areas of research in the assessment of pharmacokinetics in patients with chronic kidney disease

Chronic kidney disease (CKD) has been shown to alter the pharmacokinetics of drugs that are eliminated not only via the renal pathway but also by nonrenal clearance and transport. Dosing recommendations in subjects with CKD have historically come from small pharmacokinetic (PK) studies, which have been insulated from the broader clinical development strategy. Opportunities for prospective strategic integration of both preclinical and clinical data on drug clearance mechanisms, model-based approaches, and clinical knowledge of therapeutic index are therefore often missed in designing and analyzing the results of PK studies in subjects with CKD, and eventually providing dosing recommendations. These considerations are valuable in designing informative PK studies in subjects with CKD, as well as for guiding kidney function-related inclusion/exclusion criteria in the broader clinical program and ultimately defining dosing guidelines that optimize benefit-risk balance for these special patient populations based on all available data. This paper offers points to consider for drug developers to increase adoption of a contemporary multidisciplinary approach, which includes key considerations on study design and conduct, methodologies for analysis (population PK and physiologically based PK modeling), and a roadmap to interpret the effect of kidney function on the overall benefit-risk profile of drugs in development.