Precise quantitative evaluation of pharmacokinetics of cisplatin using a radio-platinum tracer in tumor-bearing mice

Time-course analysis of cisplatin induced AKI in preclinical models: implications for testing different sources of MSCs

BACKGROUND

Kidneys are at risk from drug-induced toxicity, with a significant proportion of acute kidney injury (AKI) linked to medications, particularly cisplatin. Existing cytoprotective drugs for cisplatin-AKI carry side effects, prompting a search for better biological therapies. Mesenchymal Stem Cells (MSCs) are under consideration given their regenerative properties, yet their clinical application has not achieved their full potential, mainly due to variability in the source of MSC tested. In addition, translating treatments from rodent models to humans remains challenging due to a lack of standardized dosing and understanding potential differential responses to cisplatin between animal strains.

METHOD

In the current study, we performed a time-course analysis of the effect of cisplatin across different mouse strains and evaluated gender related differences to create a robust preclinical model that could then be used to explore the therapeutic efficacy of different sources of MSCs for their ability to reverse AKI.

RESULT

Our data indicated that different mouse strains produce differential responses to the same cisplatin dosing regimen. Despite this, we did not observe any gender-related bias towards cisplatin nephrotoxicity. Furthermore, our time-course analysis identified that cisplatin-induced inflammation was driven by a strong CXCL1 response, which was used as a putative biomarker to evaluate the comparative therapeutic efficacy of different MSC sources in reversing AKI. Our data indicates that UC-MSCs have a stronger anti-inflammatory effect compared to BM-MSCs and AD-MSCs, which helped to ameliorate cisplatin-AKI.

CONCLUSION

Overall, our data underscores the importance of using an optimized preclinical model of cisplatin-AKI to test different therapies. We identified CXCL1 as a potential biomarker of cisplatin-AKI and identified the superior efficacy of UC-MSCs in mitigating cisplatin-AKI.

Production and synthesis of a novel 191Pt-labeled platinum complex and evaluation of its biodistribution in healthy mice

We previously reported that our sugar-conjugated platinum complex (cis-dichloro [(2-fluoro-α-d-glucopylanosidyl) propane-1,3-diamine] platinum: FGC-Pt) has low toxicity and tumor growth inhibitory effect comparable to that of cisplatin. We focused on radioactive Pt isotopes in order to analyze the kinetics of FGC-Pt using gamma-ray imaging techniques, assuming that FGC-Pt could be used for chemotherapy in the future. Therefore, in this study, we aimed to develop a non-invasive method to analyze the biodistribution of FGC-Pt using 191Pt-labeled FGC-Pt ([191Pt]FGC-Pt). 191Pt was produced via the (n,2n) reaction induced by accelerator neutrons. [191Pt]FGC-Pt was prepared using two different methods. In the first method, [191Pt]FGC-Pt (method A) was obtained through the accelerator neutron irradiation of FGC-Pt. In the second method, [191Pt]FGC-Pt (method B) was synthesized using [191Pt]K2PtCl4, which was obtained by the accelerator neutron irradiation of K2PtCl4. Highly purified [191Pt]FGC-Pt was obtained using the latter method, which suggests that the synthetic method using a 191Pt-labeled platinum reagent is suitable for the radioactivation of platinum complexes. We also aimed to investigate whether a significant correlation existed between the biodistribution of FGC-Pt and [191Pt]FGC-Pt in healthy mice 24 h after tail vein administration. FGC-Pt and [191Pt]FGC-Pt were similarly distributed in healthy mice, with a higher accumulation in the liver and kidney 24 h post injection. In addition, a significant correlation (p < 0.05, r = 0.92) between the 191Pt radioactivity concentration (%ID/g (gamma counter)) and platinum concentration (%ID/g (ICP-MS)) was observed in 13 organs. These results suggest that 191Pt-labeled compounds, synthesized using radioactive platinum reagents, can be used to confirm the biodistribution of platinum compounds. Our study on the biodistribution of [191Pt]FGC-Pt is expected to contribute to the development of novel platinum-based drugs in the future.