statins reduce glutathione and increase caspase 3 in cell mo

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ANTI-HYPERCHOLESTEROLEMIA DRUGS IN THE
STATIN CLASS REDUCE GLUTATHIONE LEVELS AND
INCREASE CASPASE 3 ACTIVATION IN AN IN VITRO
CELL MODEL.
J. F. Pregenzer, J. M. McKim, Jr., P. C. Wilga and D. K. Petrella. CeeTox,
Kalamazoo, MI.
The ability to identify and understand the potential adverse effects of new drugs
early in the development process can help manage patient risk versus clinical benefit.
Cerivastatin (CRV), simvastatin (SMV), lovastatin (LOV), atorvastatin (ATV),
fluvastatin (FLV) and pravastatin (PRV) are in the statin class of cholesterol lowering
drugs used in the treatment of hypercholesterolemia. All have been associated
with hepatotoxicity and the skeletal muscle disorder rhabdomyolysis. CRV was recently
withdrawn from United States markets because of reports of fatal rhabdomyolysis
and high incidence of liver toxicity. It is believed that the mechanisms underlying
these adverse effects are linked to energy depletion and apoptosis. The
purpose of the present study was to screen the statin drugs in a battery of in vitro assays
designed to evaluate cytotoxic, apoptotic, and oxidative stress potential. Rat
hepatoma (H4IIE) cells were seeded into 96-well plates (10, 000/well). Following a
48 hr equilibration period the cells were treated with compounds at concentrations
of 0, 0.1, 1, 5, 10, 50, 100, and 300 uM for 24 hr. Cytotoxicity was evaluated by
measuring membrane leakage, mitochondrial function, and cell number. Oxidative
stress was assessed by measuring total glutathione (GSH) and 8-isoprostane.
Apoptosis was determined via caspase 3 activity. The hydrophobic statins (FLV,
CRV, SMV, LOV, and ATV) produced a modest decrease in ATP, cell number, and
mitochondrial function, but had pronounced effects on the reduction of total GSH
pools and induction of caspase 3 activity. In contrast, the hydrophilic statin (PRV)
had no measurable effects in this system. These data are consistent with published
studies in which the mechanism(s) associated with statin toxicity are energy depletion
and induction of apoptosis. Moreover, these data indicate that early screening
with a cell-based system that evaluates several biochemical processes can provide
important information on the relative safety of new drugs prior to entering animal
studies or beginning clinical trials.

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Potential Role of Cerebral Glutathione in the Maintenance of Blood-Brain Barrier Integrity in Rat
Journal Neurochemical Research
Publisher Springer Netherlands
ISSN 0364-3190 (Print) 1573-6903 (Online)
Issue Volume 24, Number 12 / December, 1999
DOI 10.1023/A:1021191729865
Pages 1507-1514


(1) Predictive Toxicology Research Group, Industrial Toxicology Research Centre, Lucknow-, 226 001, India
(2) Department of Biochemistry, College of Medicine, University of Vermont, Burlington, VT, 05405


Abstract Using the model of glutathione (GSH) depletion, possible role of GSH in the maintenance of blood-brain barrier (BBB) integrity was evaluated in rats. Administration (ip) of GSH depletors, diethyl maleate (DEM, 1–4 mmol/kg), phorone (2–3 mmol/kg) and 2-cyclohexene-1-one (CHX, 1 mmol/kg), to male adults was found to deplete brain and liver GSH and increase the BBB permeability to micromolecular tracers (sodium fluorescein and [14C]sucrose) in a dose-dependent manner at 2h. However, BBB permeability to macromolecular tracers such as horseradish peroxidase and Evan's blue remained unaltered. It was also shown that observed BBB permeability dysfunction was associated with brain GSH depletion. A lower magnitude of BBB increase in rat neonates, as compared to adults, indicated a possible bigger role of GSH in the BBB function of mature brain. The treatment with N-acetylcysteine, methionine and GSH provided a partial to full protection against DEM-induced brain (microvessel) GSH depletion and BBB dysfunction; however, the treatment with -tocopherol, ascorbic acid and turmeric were not effective. Our studies showed that cerebral GSH plays an important role in maintaining the functional BBB integrity.
Glutathione depletion - blood-brain barrier permeability - antioxidants - sulfhydryls - brain - microvessels -