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Background: Among all the treatments for ischemic stroke, antiplatelet therapy with aspirin (ASA) and clopidogrel (CLP), known as dual antiplatelet therapy (DAPT), and ginkgo diterpene lactone meglumine injection (GDLI) are considered as the first line therapeutic approach for western medicine and Chinese medicine, respectively. Since carboxylesterase 1 (CES1) is the predominant hydrolase responsible for the biotransformation of CLP into its inactive metabolite (CLPM) and its mediated herb-drug interactions have been reported by us and others [1], the current study was proposed aiming to investigate the potential CES1 mediated interactions between DAPT and GDLI in ischemic stroke rat model established by autologous blood clot method.
Methods: Male Sprague-Dawley (SD) rats were randomly divided into six groups (G1-G6) to receive 14-day treatments of 0.5% CMC-Na (G1 Control, G2 Sham, G3 Model Control), DAPT at bolus of ASA 10.3 mg/kg + CLP 31 mg/kg followed by ASA 10.3 mg/kg + CLP 7.75 mg/kg for 13 days (G4), GDLI at 2.6 mg/kg (G5) and DAPT+GDLI with a 2-hour interval between two treatments (G6). On Day 14, all the rats were sacrificed 2 hours after the last dosing followed by collecting blood and liver to prepare plasma and liver microsomal samples for further analyses. The comparison of the steady-state plasma concentrations of CLP, CLPM, and clopidogrel active metabolite derivative (CAMD) determined via LC-MS/MS was conducted using Student's t-test. The assessment of CES1 activities in liver microsomes using a selective bioluminescent probe NLMe [2] and the determination of mRNA expressions of Ces1e in the liver using quantitative real-time PCR from different treatment groups were analyzed by one-way ANOVA, followed by Tukey's multiple comparisons test.
Results: Although there was no significant difference in steady-state plasma concentrations of CLP, CAMD between G4 and G6 groups, a trend of increase in CLPM concentrations in G6 was noted. CES1 activities represented by the Css(CLPM)/Css(CLP) in G6 was significantly lower than those from G4, indicating a potential inhibition of it by GDLI, which was further supported by the decreased Ces1e mRNA expression in liver in G6 versus that of G4. Besides, a significant lower Ces1e mRNA expression in G5 versus that in G4 was noted, suggesting the direct inhibition of CES1 by GDLI.
Conclusions: The combination use of DAPT and GDLI for 14 days in ischemic rats led to significant CES1-mediated pharmacokinetic interactions, resulting in decreased biotransformation from CLP to CLPM, CES1 activity and Ces1e mRNA expression in liver in comparison to that from DAPT.
Acknowledgments: Funding support from Guangdong-Hong Kong-Macao Joint Laboratory for New Drug Screening.
Reference:
[1] Zhang J, Xiao M, Ji X, et al. Inhibition of Radix Scutellariae flavones on carboxylesterase mediated activations of prodrugs. Life Sci. 2022; 305: 120743.
[2] Zhang J, Wang D, Zou L, et al. Rapid bioluminescence assay for monitoring rat CES1 activity and its alteration by traditional Chinese medicines. J Pharm Anal. 2020; 10(3): 253-262.