Phytosterols and Lack of Occurrence of Cholestasis in Rats Nourished Parenterally or Orally.

Phytosterols, which are plant sterol, are significantly present in most intravenous lipid emulsions (ILEs) and are considered toxic substances leading to parenteral nutrition-associated cholestasis (PNAC). Glutamine on the contrary, is considered protective against the occurrence of PNAC. In this study we pursue several objectives. First we want to determine the plasma amount of phytosterols deriving from different oil sources in rats receiving parenteral nutrition, and compare it with those in rats on standard oral diet. Subsequently, we want to verify whether phytosterols have an impact on the occurrence of cholestasis. Finally, we intend to verify whether the addition of glutamine changes the outcomes. To this end, plasma phytosterols (β-sitosterol, campesterol, and stigmasterol) were quantified by gas chromatography-mass spectrometry after performing a lipid extraction procedure in 15 weaning rats randomly divided into 3 groups receiving parenteral nutrition with soy bean oil (IL), IL plus glutamine (ILG), and chow respectively for five days. Diets were isocaloric and isonitrogenous. After killing, blood and liver samples were taken to determine plasma phytosterols and check liver histology. Every sample was triple-tested. Among phytosterols, sitosterol had the highest plasma level in all the groups. Its highest concentrations were found in the ILG group, followed by the IL group. Plasma stigmasterol levels were significantly higher in both the IL and ILG groups. Plasma campesterol levels were similar across groups including the one receiving chow. None of the liver specimens showed PNAC. In conclusion, sitosterol and stigmasterol levels were highly present in the plasma, particularly in all rats receiving parenteral nutrition. No cases of PNAC appear to have occurred. Addition of glutamine to the parenteral formulation seemed not to matter, as PNAC did not occur.