Mitochondrial dysfunction and delayed hepatotoxicity: another lesson from troglitazone.

AIMS/HYPOTHESIS: Troglitazone was approved for treatment of type 2 diabetes mellitus, but by 2000 it had been removed from all world markets due to severe drug-induced liver injury. Even today, we still do not know how many patients sustained a long-term liver injury. No system is in place to acquire that knowledge. Regarding toxicity mechanisms, controversy persists as to which ones are class effects of thiazolidinediones (TZDs) and which are unique to troglitazone. This study aims to provide long-term outcome data and new insights on mechanisms of troglitazone-induced liver injury. METHODS: This case series reports the liver injuries sustained by eleven type 2 diabetic patients treated with troglitazone between 1997 and 2000. Exhaustive review of medical records was performed for all patients. Long-term outcomes were available for all the non-fatal cases. A comprehensive literature review was also performed. RESULTS: Long-term liver injury progressing to cirrhosis was identified in seven patients. All eleven cases had liver injury patterns consistent with troglitazone toxicity. Analysis of these cases and of the experimental troglitazone toxicity data points to mitochondrial toxicity as a central factor. The general clinical patterns of mitochondrial hepatotoxic events are reviewed, as are the implications for other members of the TZD family. CONCLUSIONS/INTERPRETATION: This analysis enables the liver injury induced by troglitazone to be better understood. In future cases of delayed drug-induced liver injury that progresses after discontinuation, the possibility of mitochondrial toxicity should be considered. When appropriate, this can then be evaluated experimentally. Such proactive investigation may anticipate clinical risk before a large-scale therapeutic misadventure occurs. Drug-induced liver injury due to mitochondrial hepatotoxins may be less unpredictable than has previously been surmised.

Expression of cytokeratins 7 and 20 in carcinomas of the gastrointestinal tract.

AIMS: The differential expression of cytokeratin (CK) 7 and 20 by carcinomas may help in determining the primary site of a metastatic tumour. The aim of this study was to extend the published data on CK7 and CK20 expression in epithelial neoplasms of the gastrointestinal tract by considering the degree of differentiation and including some unusual neoplasms. METHODS AND RESULTS: Cases referred to the Armed Forces Institute of Pathology were studied prospectively for immunohistochemical expression of CK7 and CK20. Lesions from 105 patients were analysed. Adenocarcinomas of the upper gastrointestinal tract were positive for both CK7 and CK20 in 78% of cases; only poorly differentiated lesions were CK7-. Well-differentiated and moderately differentiated adenocarcinomas of the large intestine, including appendix, were CK7-/CK20+ in the great majority of cases, as were goblet cell carcinoids, but half of the poorly differentiated adenocarcinomas exhibited aberrant expression, as did most of the mixed goblet cell carcinoid/adenocarcinomas. All five high-grade neuroendocrine carcinomas were negative for both CK7 and CK20. CONCLUSIONS: Not only the site but also the grade and histological type of a gastrointestinal carcinoma should be considered when assessing cytokeratin phenotype.

Cryptic Mucor infection leading to massive cerebral infarction at initiation of antileukemic chemotherapy.

A 74-year-old man with newly diagnosed acute myelogenous leukemia unexpectedly suffered a massive cerebral infarct on day 2 of induction chemotherapy. Clinically, the hemorrhagic infarct was thought to be due to leukostasis and thrombocytopenia. Necropsy, however, revealed that Zygomycetes-type hyphae had infiltrated cerebral vessels in and near the infarct. The fungal infection was clinically silent otherwise, although fungal elements were also identified in the lung at autopsy. This case illustrates how closely fungal infection may resemble a leukemia-associated cerebrovascular accident.