Thiazolidinedione toxicity to isolated hepatocytes revealed by coherent multiprobe fluorescence microscopy and correlated with multiparameter flow cytometry of peripheral leukocytes

Thiazolidinediones (TZDs) are effective for the treatment of adult-onset in sulin-resistant diabetes. Unfortunately, TZDs are associated with sporadic hepatic dysfunction that is not predictable from experimental animal studie s. We investigated the response of isolated rat and human hepatocytes to va rious TZDs using biochemical assays, coherent multiprobe fluorescence micro scopy and flow cytometric analyses. The results identified direct effects o f TZD on mitochondria from live human and rodent hepatocytes. The multiprob e fluorescence assays showed disruption of mitochondrial activity as an ini tiating event followed by increased membrane permeability, calcium influx a nd nuclear condensation. Other TZD-related cellular effects were increased hepatic enzyme leakage, decreased reductive metabolism and cytoplasmic aden osine triphosphate depletion. Mitochondrial effects were similar in cryopre served hepatocytes from diabetic or non-diabetic donors. Peripheral blood m ononuclear cells (PBMCs) had baseline mitochondrial energetics and metaboli sm comparable with isolated hepatocytes. Mitochondrial effects in isolated hepatocytes were found in human PBMCs exposed to the TZDs. The relative pot ency of TZDs for causing hepatocyte and PBMC effects was troglitazone > pio glitazone > rosiglitazone. These studies clearly demonstrated that hepatic alterations in vitro are characteristic of TZDs, with only quantitative dif ferences in subcellular organelle dysfunction. Monitoring mitochondrial fun ction in isolated PBMCs may be beneficial in diabetics undergoing TZD thera py.