Cholesterol-cholate-butterfat diet offers multi-organ dysfunction in rats.

BACKGROUND: Comparable to commercial expensive high-fat diets, cholesterol-cholate-butterfat (CCB) diet has also been used to induce hyperlipidemia in rats. Our objective was to explore its influence on multiple organs. Consequence of fasting was also analysed. METHODS: Rats in groups 1 and 2 received normal diet (ND) whereas groups 3 and 4 received CCB-diet. Food was withdrawn daily for two hours from groups 2 (ND-F) and 4 (CCB-F). Blood was collected at fourth and sixth week for biochemical estimation; Morris water maze was done in the sixth week for learning ability and memory; after which aortae were isolated for vascular reactivity. RESULTS: Apart from hyperlipidemia, CCB also induced hyperglycemia with marked increase in hepatic enzymes: gamma-glutamyl transferase (GGT), alanine and aspartate aminotransferase (ALT and AST); and vascular biomarkers: uric acid (UA), phosphorus and alkaline phosphatase (ALP). Isolated aortae, pre-contracted with phenylephrine, were less responsive to acetylcholine indicating endothelial dysfunction--serum nitric oxide (NO) production was limited with subsequent inhibition of endothelial NO synthase. CCB diet also compromised learning ability. CCB-coupled fasting potentiated hyperlipidemia but prevented memory-loss. CONCLUSION: We introduce CCB-diet for multi-organ dysfunction in rats, and propose its use for research on cardiovascular diseases and associated manifestations involving immense interplay of integrated pathways.

The synthesis, self-assembling, and biocompatibility of a novel O-carboxymethyl chitosan cholate decorated with glycyrrhetinic acid.

O-carboxymethyl chitosan (OCMC) was firstly decorated with cholic acid (CA) to acquire an amphiphilic polymer under alkaline condition. Then glycyrrhetinic acid (GA) was conjugated to the polymer via a succinate linker and finally treated with NaCO3 solution to obtain new conjugates for potential liver targeted delivery. These conjugates formed uniform aggregates with low critical aggregation concentrations (0.028-0.079 mg/mL) in PBS. The average diameter of cholic acid modified carboxymethyl chitosan (CMCA) aggregates (110-257 nm) decreased with the increase of CA substitution degree and became slightly larger after GA modification. Negative zeta potential (-15 mV) of GA decorated CMCA (GA-CMCA) revealed that the formation of negatively charged shells and spherical morphology was observed under transmission electron microscopy. Furthermore, hemolysis test, in vitro cytotoxicity assay and cellular uptake study all demonstrated the safety and feasibility of these conjugates as a promising carrier for liver targeted drug delivery.

Effect of ketocholate derivatives on methotrexate uptake in Caco-2 cell monolayers.

PURPOSE: The bile salts (BS) cholate (C) and 12-monoketocholate (12-MKC) have been shown to inhibit the transcellular permeation of methotrexate (MTX) across Caco-2 cell monolayers. The aim of this study was to investigate the mechanism of this inhibition by comparing the effects of C, 7-MKC, 12-MKC, 3,7-diketocholate (DKC) and triketocholate (TKC) on MTX uptake by Caco-2 cells. METHODS: Critical micelle concentrations (CMCs) and cytotoxicities of BS and their effects on membrane fluidity Caco-2 cells were determined by standard methods. MTX uptake by Caco-2 cell monolayers was determined using LC-MS/MS. RESULTS: Replacing hydroxyl groups in C with keto groups and changing from 7-MKC to 12-MKC resulted in BS with lower cytotoxicity, higher CMC and decreased ability to inhibit the uptake of MTX. 7- and 12-MKC increased membrane fluidity of hydrophilic regions of Caco-2 cell membranes, DKC and TKC increased membrane fluidity of hydrophobic regions and C had little effect on membrane fluidity of either region. CONCLUSION: Replacing hydroxyl groups in C with keto groups produces BS with different physicochemical properties and biological effects. Since ketocholates (but not C) decrease MTX uptake in parallel with increasing membrane fluidity, it is suggested that ketocholates inhibit MTX influx transporters indirectly through disturbing their lipid environment.