mRNA expression levels of cytochrome P450 CYP1A2, CYP3A4, and CYP3A5 in the epidermis: a focus on individual differences among Japanese individuals

Various cytochrome P450 enzymes (CYPs) that contribute to drug metabolism are expressed in the skin. However, variation among individuals in CYP expression profiles is not well-understood.To investigate CYPs related to the metabolism of transdermal preparations in Japan, multiple skin tissue specimens of individuals of Japanese descent were prepared, and the mRNA expression levels of CYP1A2, CYP3A4, and CYP3A5 were measured. Associations between the expression patterns of these CYPs and body mass index (BMI) were also investigated.There were considerable individual differences in epidermal CYP1A2 mRNA expression levels, and CYP1A2 showed a weak positive correlation with CYP3A4 mRNA expression levels. In contrast to previous results for other organs, epidermal CYP3A4 mRNA expression levels showed a weak positive correlation with BMI.CYP3A4 in the epidermis may have been locally enhanced as a defence mechanism against xenobiotics in response to impaired barrier function. These differences in mRNA expression in the skin may affect the transdermal absorption of drugs, such as lidocaine and fentanyl, which are metabolised by multiple overlapping CYPs.Our study provides new insights into drug metabolism in the skin. These results are valuable for predicting drug effects and transdermal drug transfer rates in Japanese patients.

Effect of purified eicosapentaenoate ethyl ester on fibrinolytic capacity in patients with stable coronary artery disease and lower extremity ischaemia

BACKGROUND

Lower extremity ischaemia is often complicated by coronary artery disease (CAD). Patients with CAD often have impaired fibrinolytic capacity. Plasma plasminogen activator inhibitors (PAI) levels are known to be associated with levels of atherogenic lipids. Purified eicosapentaenoic acid reduces atherogenic lipid levels.

OBJECTIVE

To examine the effect of purified eicosapentaenoic acid ethyl ester (EPA) on the fibrinolytic capacity in patients with stable CAD and arteriosclerosis obliterans (ASO).

METHODS

Plasma levels of PAl activity and tissue-type plasminogen activator (t-PA) antigen were measured. We administered 1800 mg/day EPA for 8 weeks to 25 patients.

RESULTS

Mean baseline plasma PAI activity (P < 0.01) and t-PA antigen (P < 0.01) levels were higher in the patient group than they were in the control group. At the conclusion of EPA administration, significant reductions in PAI activity (P < 0.01), t-PA antigen (P < 0.01) and serum levels of triglyceride (P < 0.01), total (P < 0.05) and low-density lipoprotein (P < 0.05) cholesterols were observed. Changes in PAI activity levels caused by EPA administration showed positive linear correlations with those in low-density lipoprotein cholesterol (r = 0.411, P < 0.05) and triglyceride (r = 0.652, P < 0.01).

CONCLUSION

These findings indicate that the fibrinolytic capacity in patients with CAD and ASO is decreased by increased PAI activity, but that EPA may correct this fibrinolytic impairment by decreasing PAI activity via its inhibitory effect on atherogenic lipids.