Dietary Fatty Acid Saturation Modulates Sphingosine-1-Phosphate-Mediated Vascular Function.

Area of Science:

• Cardiovascular Biology
• Lipid Metabolism
• Cellular Physiology

Background:

• Sphingolipids, like sphingosine-1-phosphate (S1P), are vasoactive compounds integral to cell membranes.
• Dietary fatty acids can modify sphingolipid function and vascular responses.
• Caveolae, specialized membrane microdomains, are implicated in regulating vascular tone.

Purpose of the Study:

• To investigate how dietary fatty acid saturation affects vasoconstriction to S1P.
• To determine the role of caveolae and rho kinase in mediating these dietary effects.
• To examine the influence of n-3 polyunsaturated fats on S1P-induced vasoconstriction.

Main Methods:

• Comparison of wild-type (WT) and caveolin-1-deficient (cav-1 KO) mice fed low-fat, high-saturated fat (HF), or high-fat with menhaden oil (MO) diets.
• Assessment of vascular responses, including vasoconstriction to S1P and phenylephrine (PE).
• Analysis of gene and protein expression of caveolin-1, rho, and rho kinase in mouse arteries.

Main Results:

• High-fat diets altered weight gain differently in WT and cav-1 KO mice.
• Dietary interventions did not affect caveolin-1, rho, or rho kinase expression in WT mouse arteries.
• S1P-induced vasoconstriction was reduced by HF diet in WT mice, restored by MO diet, and diminished in cav-1 KO mice.
• Rho kinase inhibition affected S1P constriction only in WT mice fed the MO diet.

Conclusions:

• Dietary fatty acids modulate vascular S1P responses through a caveolar-dependent mechanism.
• Dietary n-3 polyunsaturated fats enhance vascular responses to S1P.
• Caveolae play a critical role in mediating the effects of dietary fat saturation on vasoconstriction.