The combination of nuclear and mitochondrial mutations as a risk factor for idiosyncratic toxicity

A case of melphalan sustained accumulation in an 80-year old patient

Case We report the case of melphalan accumulation in an 80-year old female with multiple myeloma. Her initial health status was good except for a moderate chronic renal failure (estimated glomerular filtration rate: 31 ml/min) and anemia. Among other drugs, her usual treatment included trimethoprim/sulfamethoxazole and the patient received melphalan from day 1 to day 4 for multiple myeloma. On day 13, she was admitted in intensive care unit for acute renal failure and severe sepsis with pancytopenia. Usual treatments were stopped. Melphalan blood concentrations were 123.6 ng/ml on day 16 and 87.5 ng/ml on day 17 while cerebrospinal fluid concentration was 173.8 ng/ml on day 25. Patient recovered on day 30. Melphalan accumulation may be explained by substrate competition between sulfamethoxazole and melphalan in metabolism pathway and chronic renal failure. Conclusion close clinical and renal monitoring should be performed in patient receiving melphalan and sulfamethoxazole.

The plasma proteome, adductome and idiosyncratic toxicity in toxicoproteomics research

Toxicoproteomics uses the discovery potential of proteomics in toxicology research by applying global protein measurement technologies to biofluids and tissues after host exposure to injurious agents. Toxicoproteomic studies thus far have focused on protein profiling of major organs and biofluids such as liver and blood in preclinical species exposed to model toxicants. The slow pace of discovery for new biomarkers, toxicity signatures and mechanistic insights is partially due to the limited proteome coverage derived from analysis of native organs, tissues and body fluids by traditional proteomic platforms. Improved toxicoproteomic analysis would result by combining higher data density LC-MS/MS platforms with stable isotope labelled peptides and parallel use of complementary platforms. Study designs that remove abundant proteins from biofluids, enrich subcellular structures and include cell specific isolation from heterogeneous tissues would greatly increase differential expression capabilities. By leveraging resources from immunology, cell biology and nutrition research communities, toxicoproteomics could make particular contributions in three inter-related areas to advance mechanistic insights and biomarker development: the plasma proteome and circulating microparticles, the adductome and idiosyncratic toxicity.