aProximate™ as a novel, predictive model of aminoglycoside-induced nephrotoxicity

Aminoglycosides are a class of antibiotics favoured for their bactericidal activity and their cost effective route of production. However, these compounds are known to be toxic in a range of organ systems, including the kidney.

The aProximate™ model can be utilized to give an indication of the nephrotoxicity of a compound, using the FDA approved, clinically relevant biomarkers: NGAL, clusterin and KIM-1. Here we demonstrate this using a panel of aminoglycosides, which are known to induce nephrotoxicity to varying degrees, in vivo. aProximate™ monolayers were generated by isolating human proximal tubule cells (hPTCs) followed by culture on Transwell filter inserts. The monolayers were grown to confluency before being challenged with a range of aminoglycosides (gentamicin, streptomycin, tobramycin, amikacin and neomycin) at 0–3000 μM for up to 96 hours. Monolayer integrity was assessed by via of trans-epithelial electrical resistance (TEER) and cell viability via the LDH and ATP assays. Biomarker generation was assessed by ELISA at the protein level, using a multiplex ELISA system. Exposure of the aProximate™ monolayers to the aminoglycosides resulted in significant decrease in TEERs, along with a decrease in cell viability. The amount of KIM-1, NGAL and clusterin secreted by the monolayers were significantly more when compared to untreated monolayers when exposed to, for instance, neomycin, tobramycin and gentamicin.

In summary, these data suggest that aProximate™ hPTC monolayers express clinically relevant biomarkers of nephrotoxicity and their apical release is induced by aminoglycoside challenge.

The model was able to detect varying levels of toxicity between compounds of this class, mirroring what is reported in vivo, demonstrating their potential as a predictive in vitro model for toxicity screening in pharmaceutical development.

Find out more about our kidney toxicity assays using the aProximate™ and glomerulus models