Phenytoin treatment reduces atherosclerosis in mice through mechanisms independent of plasma HDL-cholesterol concentration

Role of CYP2C9 polymorphism in phenytoin-related metabolic abnormalities and subclinical atherosclerosis in young adult epileptic patients

PURPOSE

We investigated the influence of the CYP2C9 polymorphism on the lipid profile, insulin resistance, and subclinical atherosclerosis in young epileptic patients.

METHODS

We performed a cross-sectional study to evaluate the association between CYP2C9 polymorphism and lipid profile, glucose homeostasis, and subclinical atherosclerosis in young epileptic patients via the ankle brachial index.

RESULTS

The frequencies of CYP2C9*1 (CYP2C9 wild type gene) and CYP2C9*3 (CYP2C9 polymorphism gene) were 75% and 25%, respectively. The mean serum total triglyceride and LDL levels were significantly higher in the wild type gene subjects than in the CYP 2C9 polymorphism gene subjects. Also, the CYP 2C9 polymorphism had marginally significant lower mean serum HDL levels than the wild type gene subjects. No patients with CYP 2C9 polymorphism gene had elevated fasting blood sugar, and insulin resistance was found in only 10 of the 75 subjects. The mean ABI was statistically significantly lower in the wild type subjects than in the CYP2C9 polymorphism gene subjects.

CONCLUSION

Our study indicates that young epileptic patients with the CYP2C9 polymorphism gene have a low risk of subclinical atherosclerosis.

Cardiovascular risk factors and homocysteine in epilepsy

Epidemiological studies have found the risk for heart disease and stroke are increased in persons with epilepsy. Anti-epileptic drugs (AEDs) have varying effects on serum lipids and homocysteine-an independent risk factor for coronary disease. The prevalence of cardiovascular risk factors (high cholesterol, hypertension, diabetes, obesity and smoking) and homocysteine were investigated in a multiethnic epilepsy population. Data included demographics, clinical factors, lab assessments and supplementation patterns. Mean age was 45 years (71 males and 94 females)-75 were African American, 27 Latino and 60 Caucasian. Fifty-two percent of participants had two or more cardiovascular risk factors when compared with rates for the general population of 28%. The Framingham risk score (FRS) assessment was also used to compare risk levels. Twenty-nine percent of men and 1% of women had a FRS indicating >5% level of risk, only 7% had a FRS>10%. Cardiovascular screening and primary preventative recommendations based on the American Heart Association and supplementation should be suggested for the adult epilepsy population when appropriate.

CETP activity variation in mice does not affect two major HDL antiatherogenic properties: macrophage-specific reverse cholesterol transport and LDL antioxidant protection

CETP inhibition increases HDL cholesterol levels and presumably could contribute to human atheroprotection via increasing macrophage-specific reverse cholesterol transport (RCT) and antioxidant properties of HDL. However, the impact of CETP activity variation on these two antiatherogenic functions of HDL remain unknown. In this study, we assessed the effects of overexpressing CETP in transgenic (Tg) mice on macrophage-specific RCT and HDL ability to protect against LDL oxidative modification. [(3)H]cholesterol-labeled macrophages were injected intraperitoneally into mice maintained on a chow diet or an atherogenic diet, after which the appearance of [(3)H]cholesterol in plasma, liver and feces over 48 h was determined. The degree of protection of oxidative modification of LDL coincubated with HDL was evaluated by measuring relative electrophoretic mobility and dichlorofluorescein fluorescence. CETP-Tg mice presented decreased radiolabeled HDL-bound [(3)H]cholesterol 24 and 48 h after the label injection. However, the magnitude of macrophage-derived [(3)H]cholesterol in liver and feces did not differ between CETP-Tg and control mice on either diet. Similar results were found when [(3)H]cholesterol-labeled endogenous peritoneal macrophages were injected into the CETP-Tg and control mice. Further, the injection of endogenous macrophages from CETP-Tg mice did not alter macrophage RCT in control mice. HDL from CETP-Tg and control mice protected LDL from oxidative modification similarly, and paraoxonase 1, platelet activated factor acetyl-hydrolase and lecithin-cholesterol acyl transferase activities of transgenic mice did not differ from those of control mice. In conclusion, CETP overexpression in transgenic mice does not affect RCT from macrophages to feces in vivo or the protection conferred by HDL against LDL oxidative modification.

Systems-ADME/Tox: resources and network approaches

The increasing cost of drug development is partially due to our failure to identify undesirable compounds at an early enough stage of development. The application of higher throughput screening methods have resulted in the generation of very large datasets from cells in vitro or from in vivo experiments following the treatment with drugs or known toxins. In recent years the development of systems biology, databases and pathway software has enabled the analysis of the high-throughput data in the context of the whole cell. One of the latest technology paradigms to be applied alongside the existing in vitro and computational models for absorption, distribution, metabolism, excretion and toxicology (ADME/Tox) involves the integration of complex multidimensional datasets, termed toxicogenomics. The goal is to provide a more complete understanding of the effects a molecule might have on the entire biological system. However, due to the sheer complexity of this data it may be necessary to apply one or more different types of computational approaches that have as yet not been fully utilized in this field. The present review describes the data generated currently and introduces computational approaches as a component of ADME/Tox. These methods include network algorithms and manually curated databases of interactions that have been separately classified under systems biology methods. The integration of these disparate tools will result in systems-ADME/Tox and it is important to understand exactly what data resources and technologies are available and applicable. Examples of networks derived with important drug transporters and drug metabolizing enzymes are provided to demonstrate the network technologies.