Adult Zebrafish Model for Screening Drug-Induced Kidney Injury

Abstract

Drug-induced kidney injury is a serious safety issue in drug development. In this study, we evaluated the usefulness of adult zebrafish as a small in vivo system for detecting drug-induced kidney injury. We first investigated the effects of typical nephrotoxicants, gentamicin and doxorubicin, on adult zebrafish. We found that gentamicin induced renal tubular necrosis with increased lysosome and myeloid bodies, and doxorubicin caused foot process fusion of glomerular podocytes. These findings were similar to those seen in mammals, suggesting a common pathogenesis. Second, to further evaluate the performance of the model in detecting drug-induced kidney injury, adult zebrafish were treated with 28 nephrotoxicants or 14 nonnephrotoxicants for up to 4 days, euthanized 24 h after the final treatment, and examined histopathologically. Sixteen of the 28 nephrotoxicants and none of the 14 nonnephrotoxicants caused drug-induced kidney injury in zebrafish (sensitivity, 57%; specificity, 100%; positive predictive value, 100%; negative predictive value, 54%). Finally, we explored genomic biomarker candidates using kidneys isolated from gentamicin- and cisplatin-treated zebrafish using microarray analysis and identified 3 candidate genes, egr1, atf3, and fos based on increased expression levels and biological implications. The expression of these genes was upregulated dose dependently in cisplatin-treated groups and was > 25-fold higher in gentamicin-treated than in the control group. In conclusion, these results suggest that the adult zebrafish has (1) similar nephrotoxic response to those of mammals, (2) considerable feasibility as an experimental model for toxicity studies, and (3) applicability to pathological examination and genomic biomarker evaluation in drug-induced kidney injury.

Prolonged podocyte depletion in larval zebrafish resembles mammalian focal and segmental glomerulosclerosis

“…26 Non-transgenic attempts to induce podocyte injury by adding reagents to the water have not been successful for the effect was either minimal or not limited to podocytes. 27 To date the only inducible model of podocyte depletion that combines the ease of adding a reagent to the medium with the advantage of cell-specific ablation is the NTR/MTZ model. 5,14 In this study, we chose a short treatment with lowdose MTZ to deplete a subset of podocytes so that larvae survived long enough to investigate glomerular response and adaption to injury.…”

“…Another available method of podocyte depletion is laser‐induced injury, but spatial specificity of the damage requires ablation of single cells, so treatment of higher counts of larvae at the same time would not be possible 26 . Non‐transgenic attempts to induce podocyte injury by adding reagents to the water have not been successful for the effect was either minimal or not limited to podocytes 27 …”

Translational toxicology in zebrafish

“…An adult zebrafish model was used to screen novel small molecule therapeutics for liver cancer to identify compounds with a better therapeutic index than the standard of care, sorafenib [19]. Adult zebrafish were also recently validated as a model for evaluating drug-induced kidney injury [20]. Larval zebrafish have only one pair of nephrons, whereas the adult zebrafish kidney has several hundred nephrons with a similar histological structure and physiological function as the mammalian kidney Box 1.…”

“…(reviewed in the study by Kato et al [20]). The renal pathology observed in adult zebrafish exposed to nephrotoxic levels of gentamicin or doxorubicin was similar to that seen in mammals, and a screen of 28 chemicals with known nephrotoxicity and 14 with no known nephrotoxicity in humans demonstrated that 16 of the nephrotoxic chemicals and none of the negative controls caused drug-induced kidney injury in adult zebrafish.…”

Application of zebrafish to safety evaluation in drug discovery

“…Therefore, the response of adult zebrafish to nephrotoxic agents can be expected to be more similar to that of mammals. A large-scale study on the reactivity of adult zebrafish to existing nephrotoxicants, with a focus on histopathological examination, reported 94 that adult zebrafish not only exhibit pathological changes similar to those of mammals, but are also very sensitive to drugs that cause proximal tubular injury, such as cisplatin, gentamicin, among others. Even in the author’s experience, tubular necrosis, which is unlikely to occur in larvae, was histopathologically noted in adults treated with cisplatin ( Fig.…”