Trans fatty acids in membranes: the free radical path

Area of Science:

• Biochemistry
• Membrane Biology
• Free Radical Chemistry

Background:

• Most natural unsaturated fatty acids possess cis double bonds, crucial for cell membrane structure and function.
• Alterations in cis geometry, particularly isomerization to trans forms, significantly impact biological activities.
• Endogenous formation of trans fatty acids (TFAs) is a recognized biological phenomenon with implications for health.

Purpose of the Study:

• To investigate the mechanisms of cis to trans isomerization in fatty acids within biological systems.
• To explore the role of radical species in lipid isomerization in cell membranes.
• To identify endogenous factors responsible for in vivo lipid isomerization.

Main Methods:

• Utilized liposome models to simulate radical-induced isomerization of fatty acids.
• Assessed the interaction of isomerizing species with membrane lipid bilayers.
• Examined oleic acid micelles to evaluate the isomerization potential of specific radicals and molecules.

Main Results:

• Demonstrated that radical species can induce cis to trans isomerization in phospholipids.
• Liposome studies provided insights into the fundamental aspects of lipid isomerization in membranes.
• Nitrogen dioxide (*NO2) radicals did not induce isomerization in oleic acid micelles, unlike 2-mercaptoethanol.

Conclusions:

• Radical-mediated cis to trans fatty acid isomerization occurs endogenously, affecting membrane properties and biological functions.
• Sulfur-containing compounds like hydrogen sulfide (H2S) and amino acid residues are potential endogenous agents for lipid isomerization.
• Further research is ongoing to fully elucidate the in vivo mechanisms and biological significance of free radical-induced lipid isomerization.