Bile Salt Transport Assay Using LC-MS/MS
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Solution Overview
Problem
Current methods for assessing bile salt export transport and formation activity in hepatocytes are unreliable, complex, and often require radioactive materials, limiting their utility in drug discovery and liver injury prediction.
Innovation Solution
A novel in vitro method using hepatocyte preparations from human and animal livers or stable cell lines, such as HepG2, is developed to measure the modulation of bile salt export transport and formation activity by test agents, including drugs and food components, without the need for radioactive materials, allowing for inhibition, induction, activation, and regulation assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current methods for assessing bile salt export transport and formation activity are used, then measurement can be performed, but the methods are unreliable and complex
Solution Approach 1:
The patent changes the measurement parameters by using non-radioactive detection methods (LC-MS/MS) instead of traditional radioactive assays, and by modifying the incubation conditions to optimize bile salt formation and transport measurement. This resolves the contradiction by improving reliability through more accurate detection while reducing complexity by eliminating radioactive material handling procedures
Solution Approach 2:
The patent extracts and measures specific bile salt conjugates (glycocholic acid, taurocholic acid, glycodeoxycholic acid, taurodeoxycholic acid) separately from the complex incubation mixture using liquid chromatography. This extraction approach improves measurement reliability by specifically quantifying individual bile salt species while the automated chromatographic analysis reduces overall method complexity
2Measurement precision
If current methods are used, then bile salt transport can be measured, but radioactive materials are required
Solution Approach 1:
The patent replaces the radioactive detection system with a mass spectrometry-based detection system (LC-MS/MS). This substitution maintains measurement precision by providing sensitive and specific quantification of bile salt concentrations while completely eliminating the use of radioactive materials and their associated safety hazards
Solution Approach 2:
The patent uses stable, non-radioactive bile salt precursor compounds and conjugates as measurement substrates. These non-radioactive compounds can be handled without special precautions, eliminated the need for radioactive waste disposal procedures, and maintained adequate measurement precision for assessing bile salt transport and formation activity
3Adaptability or versatility
If the novel method is developed, then scalability and adaptability are improved, but the method requires new incubation and measurement systems
Solution Approach 1:
The patent develops a universal measurement system using LC-MS/MS that can detect multiple bile salt conjugates (glycocholic acid, taurocholic acid, glycodeoxycholic acid, taurodeoxycholic acid) and can be applied to various hepatocyte preparations from different species. This multi-functional approach improves adaptability across different experimental models while the standardized protocol reduces overall system complexity
Solution Approach 2:
The patent segments the measurement process into distinct analytical steps: incubation of hepatocytes with bile salt precursors, separation of bile salt conjugates by liquid chromatography, and detection by mass spectrometry. This segmentation allows each step to be optimized independently and facilitates adaptation to different experimental conditions while maintaining a manageable overall system complexity
Data Source
AI summary
A method is provided to measure modulation of bile salt export transport and/or formation activity in hepatocyte or stable cell line preparations by test agents including but not limited to drugs, drug candidates, biologicals, food components, herb or plant components, proteins, peptides, DNA, RNA. Furthermore, the method is to determine modulation of bile salt export transport and/or formation activity not only by said test agents, but further their metabolites or biotransformed products formed in situ. The bile salt export transport and/or formation activity modulation includes but not limited to inhibition, induction, activation and/or regulation. The method can be practiced to identify test agents, which have potential to cause liver injury, drug-drug interactions, and/or can be used as therapeutic agents for the treatment of cholestasis, abnormality of bile salt metabolism, liver diseases and cholesterol abnormality.