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PURPOSE: Evaluation of [68Ga]NODAGA-duramycin as a positron emission tomography (PET) tracer of cell death for whole-body detection of chemotherapy-induced organ toxicity.PROCEDURES: Tracer specificity of Ga-68 labeled NODAGA-duramycin was determined in vitro using competitive binding experiments. Organ uptake was analyzed in untreated and doxorubicin, busulfan, and cisplatin-treated mice 2 h after intravenous injection of [68Ga]NODAGA-duramycin. In vivo data were validated by immunohistology and blood parameters.RESULTS: In vitro experiments confirmed specific binding of [68Ga]NODAGA-duramycin. Organ toxicities were detected successfully using [68Ga]NODAGA-duramycin PET/X-ray computed tomography (CT) and confirmed by immunohistochemistry and blood parameter analysis. Organ toxicities in livers and kidneys showed similar trends in PET/CT and immunohistology. Busulfan and cisplatin-related organ toxicities in heart, liver, and lungs were detected earlier by PET/CT than by blood parameters and immunohistology.CONCLUSION: [68Ga]NODAGA-duramycin PET/CT was successfully applied to non-invasively detect chemotherapy-induced organ toxicity with high sensitivity in mice. It, therefore, represents a promising alternative to standard toxicological analyses with a high translational potential.

Compared to standard toxicological techniques in preclinical toxicity studies, non-invasive imaging of organ toxicity enables fast and longitudinal investigation of the whole animal. Therefore, we set out to evaluate [68Ga]Ga-NODAGA-duramycin as a positron emission tomography (PET)-tracer of cell death for detecting chemotherapy-induced organ toxicity.MethodsNODAGA-duramycin was radiolabeled with 68Ga, and quality control was done by thin layer chromatography and high performance liquid chromatography. Tracer specificity was determined in vitro by performing competitive binding experiments on ethanol treated cells. To optimize the timing of the PET/CT-based tracer evaluation, kinetic studies were performed in untreated and cisplatin-treated (20 mg/kg BW, intraperitoneal (i.p.)) BALB/cAnNRj mice. Organ uptake was analyzed in doxorubicin (4 mg/kg BW, i.p.)-, busulfan (18.8 mg/kg KG, i.p.)-, and cisplatin-treated (20 mg/kg BW, i.p.) mice, and in untreated control mice 2 hours after intravenous injection of 5–10 MBq [68Ga]Ga-NODAGA-duramycin. For immunofluorescence validation, tissue sections were stained with anti-active caspase-3 antibody. Blood and serum samples were collected to determine platelet count, aspartate transaminase, alanine transaminase, urea, creatinine, and creatine kinase values.ResultsIn vitro experiments confirmed specific binding of [68Ga]Ga-NODAGA-duramycin to dying cells. The biodistribution analysis revealed a blood half-life of 10–17 minutes and a predominantly urinary excretion of the radiotracer. Doxorubicin-, busulfan-, and cisplatin-induced organ toxicities were detected successfully using [68Ga]Ga-NODAGA-duramycin PET/CT and confirmed by immunohistochemistry as well as blood parameter analysis. Busulfan-related spleno-, cardio-, and pneumotoxicity as well as cisplatin-induced cardio- and pneumotoxicity were detected even earlier by [68Ga]Ga-NODAGA-duramycin PET/CT than by blood parameters and histological stainings. In livers and kidneys, differences between treated and untreated animals tended to occur in PET/CT at later time points than in histology due to the relatively high background in these organs. However, trends over time were comparable.Conclusion[68Ga]Ga-NODAGA-duramycin PET/CT was successfully applied to non-invasively detect chemotherapy-induced organ toxicity with high sensitivity in preclinical studies. It even depicted some toxic effects prior to immunohistochemistry and blood parameter analysis and represents a promising alternative or complementary method to standard toxicological analyses. Furthermore, the tracer has a high translational potential and may provide a valuable link between preclinical and clinical research.

Background Aphthae constitute one of the major signs in Behcet's disease (BD) and recurrent aphthous stomatitis (RAS). No scientific study has yet explored the relationship of hepcidins, which have antimicrobial effects, with RAS and BD. Objectives In this study, we aimed to evaluate by immunohistochemistry whether hepcidin is synthesized by the salivary glands and to measure levels of prohepcidin and hepcidin (an antibacterial peptide) in the serum and saliva of patients with BD and RAS. Methods The study included 25 BD patients and 30 RAS patients, as well as a control group comprising 25 healthy individuals. Serum and saliva samples were collected at the same time from all subjects. Levels of prohepcidin and hepcidin were measured by ELISA. The presence of hepcidin in salivary glands was assessed by immunohistochemistry. Results Hepcidin was localized in the striated ducts of the sublingual and parotid glands. Saliva prohepcidin and hepcidin levels were correlated with blood levels. Saliva prohepcidin levels were found to be lower in RAS patients than in BD patients and healthy controls (P