| Popis |
Effect of the CB1 agonist ACEA on P450 metabolic activity Introduction: The interaction between the endocannabinoid system (ECS) and Cytochrome P450 (CYP) enzymes is critical for understanding cannabinoid-drug interactions and potential metabolic modulation. Although the link between the ECS and CYP regulation is not yet established, recent studies suggest that the hypothalamic-pituitary-adrenal (HPA) axis may play a role in mediating these effects. However, the involvement of the HPA axis remains unproven. This study is among the first to explore how CB1 receptor activation by ACEA may modulate CYP enzyme activity through comprehensive in vivo and in vitro methods. Objective: To evaluate the impact of ACEA on CYP enzyme activity across different doses, focusing on isoform-specific inhibition parameters (IC50 and Ki) and the effects of CB1 sustained activation on the liver CYP enzymes in wistar albino rats. Methods: In an in vivo study, three groups of Wistar rats (n=10) received ACEA at doses of 0.25, 1, and 4 mg/kg over 7 days. Two control groups (n=10) included rats treated with phenobarbital (a CYP inducer) and saline. Following administration, liver and jejunum tissues were harvested, and liver microsomes were isolated to measure CYP content and activity. Total protein content was assessed using the BCA Pierce® Protein Assay Kit, and total CYP levels were determined via spectral quantitation with a double-beam spectrophotometer. Blood samples were analysed at Veterinary University Brno. In vitro experiments included direct incubations with drug naive pooled rat liver microsomes and specific CYP substrates (phenacetin, diclofenac, dextromethorphan, and testosterone) to determine IC50 and Ki for ACEA in CYP1A2, CYP2C6, CYP2D2 and CYP3A1/2. Microsomes isolated from ACEA-pretreated livers were also incubated to assess any CYP activity changes. High-performance liquid chromatography (HPLC) was used to analyse samples from these incubations, with all analyses performed in triplicates. Statistical analyses were conducted using SigmaPlot to determine significance, with graphical representation created using BioRender. Preliminary Results: Early findings indicate no significant differences in total protein content or total CYP450 levels in liver microsomes between the ACEA administration groups (0.25, 1, and 4 mg/kg) and the control group. This suggests that ACEA treatment did not affect overall measures of hepatic metabolic capacity. However, a significant increase was observed in both total protein content and total CYP450 levels in the phenobarbital-treated group compared to the control group (p < 0.05), consistent with phenobarbital’s established role as a CYP inducer. ACEA modulates CYP activity in a dose-dependent and isoform-specific manner. Specifically, ACEA shows an IC50 of 31.59 µM for CYP1A2, indicating moderate inhibition compared to potent CYP1A2 inhibitors like furafylline (IC50 ~0.07 µM) and fluvoxamine (IC50 ~0.1–0.5 µM). For CYP2C6 activity, ACEA has an IC50 of 218 µM, suggesting weak inhibition relative to standard CYP2C inhibitors such as sulfaphenazole (IC50 ~0.1 µM) and fluconazole (IC50 ~10–20 µM). This indicates that ACEA may selectively and moderately inhibit CYP1A2 while having a minimal impact on CYP2C6-mediated drug metabolism. Conclusion: These initial insights suggest that ACEA might influence CYP450 enzyme activity, which could have implications for cannabinoid-drug interactions in clinical settings. Further investigation into these interactions, along with the potential involvement of the HPA axis in modulating CYP450 through the ECS, is necessary for understanding the broader impact of cannabinoid pharmacokinetics. As data collection progresses, these findings may reveal crucial information for the safe co-administration of cannabinoids and CYP-metabolized drugs in therapeutic contexts.
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