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An Immunohistopathologic Study to Profile the Folate Receptor Beta Macrophage and Vascular Immune Microenvironment in Giant Cell Arteritis
Published on: February 8, 2019
Potentiated decrease of plasma folate levels caused by the coadministration of folic acid in rats treated with
1Department of Veterinary Medicine, Tokyo University of Agriculture and Technology, Japan.
Methotrexate (MTX) decreases plasma 5-methyltetrahydrofolic acid (5-MF) levels, indicating altered folate status. Co-administration with folic acid (FA) potentiates this effect by inhibiting 5-MF renal reabsorption.
Area of Science:
- Biochemistry
- Pharmacology
- Renal Physiology
Background:
- Plasma 5-methyltetrahydrofolic acid (5-MF) is an indicator of folate status.
- Methotrexate (MTX) is a folate antagonist.
- The interaction between MTX, folic acid (FA), and 5-MF requires further elucidation.
Purpose of the Study:
- To investigate the effect of MTX and FA co-administration on plasma 5-MF levels in rats.
- To examine the impact on 5-MF pharmacokinetics and renal clearance.
- To understand the underlying mechanisms of 5-MF level alterations.
Main Methods:
- Rats were administered MTX alone, MTX with FA, or served as controls.
- Serial blood and urine samples were collected over 9 hours.
- High-performance liquid chromatography (HPLC) was used to assay 5-MF and MTX concentrations.
- Plasma protein binding and renal clearance were analyzed.
Main Results:
- MTX administration decreased plasma 5-MF levels.
- Oral FA administration potentiated the decrease in 5-MF levels.
- Renal clearance of 5-MF increased dose-dependently with FA coadministration.
- FA did not affect 5-MF plasma protein binding or MTX pharmacokinetics.
Conclusions:
- Concurrent administration of MTX and FA leads to a significant decrease in plasma 5-MF levels in rats.
- Inhibition of 5-MF reabsorption in renal tubules is a key factor contributing to reduced plasma 5-MF.
- This study highlights a critical drug-nutrient interaction affecting folate status.
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