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Bile acid kinetic modeling in end-stage liver support patients

Jung Aleksandra, Korohoda Przemyslaw, Krisper Peter, Stadlbauer Vanessa, Stauber Rudolf E., Schneditz Daniel

Biocybernetics and Biomedical Engineering

2020

Vol. 40, no. 2

764--773

Background & Aims: Solute generation rates, distribution volumes and compartment effects control the in vivo efficiency of any extracorporeal therapy such as extracorporeal liver support (ELS) used to remove bile acids accumulating in acute-on-chronic liver patients. The aim of this study was to identify and to examine kinetic parameters of two major bile acids using mathematical modeling. Methods: The kinetics of cholic (CA) and chenodeoxycholic acid (CDCA) were described by one- and two-compartment models with central elimination by decreasing or constant extracorporeal clearance, constant bile acid generation rate, and constant apparent distribution volume. Concentration profiles collected in 13 ELS sessions done in 8 patients were included for model calculations Results: For the one-compartment model, the average volumes and generation rates were 30 ± 6 [l], 0.19 ± 0.06 [μmol/min] for CA and 22 ± 5 [l], 0.29 ± 0.08 [μmol/min] for CDCA, respectively. For the one-compartment model and average normalized concentrations, the volumes and genera- tion rates were 25 [l], 0.28 [μmol/min] for CA and 18 [l], 0.37 [μmol/min] for CDCA, respectively. For the two-compartment model, average normalized concentrations, the same initial concentration in both compartments, and assuming a 10% post-treatment rebound, the volume and generation rates were 25 [l], 0.27 [μmol/min] for CA and 19 [l], 0.32 [μmol/min] for CDCA, respectively. Conclusions: The generation rate for CDCA is higher when compared to that of CA and independent of the number of compartments. Assuming a constant extracorporeal clearance overestimates generation rate and distribution volume. The kinetic parameters of one-and two-compartment models are comparable for the same bile acid.

Kwasy żółciowe jako komponenty architektoniczne w chemii supramolekularnej

Łotowski Z.

Wiadomości Chemiczne

2003

[Z] 57, 11-12

1093--1132

One of the most important fields in modern synthetic chemistry is the preparation of molecules which can recognize and bind others and then catalyze transformations of the bound molecules i.e. „artificial enzymes”, and the construction of systems which can reproduce themselves or otherwise store and process information at the molecular level [5 ? 8]. The above mentioned properties of these novel synthetic structures will result not only from the presence therein of the various required elements, but also from their relative arrangements in space and the three-dimensional shape of the overall assembly. In other words, spatially separated elements combine to achieve an overall effect in these structures. Hence, there will be a requirement for molecules with well-defined geometries in which conformational freedom is kept under close control. This criterion can be met by designs based on rigid frameworks. The steroid nucleus is one of the largest rigid units which is readily available. There are many steroidal compounds which might be chosen as starting materials for more elaborate frameworks. However, bile acids are the most valuable group of these compounds due to their chemically different hydroxyl groups, enantiomeric purity, unique amphiphilicity, availability and low cost. Bile acids are natural polyhydroxylated steroidal acids existing in bile as sodium salts of N-acyl derivatives of glycine and taurine. They are synthesized from cholesterol and can solubilize hydrophobic substances by the formation of micellar aggregates and thus help in the digestion of fat lipids. In this review applications of bile acids as building blocks in the synthesis of macrocyclic and also open-chained supramolecular hosts are presented.