Abstract/Summary

Objective Dairy intake, despite its high saturated fatty acid (SFA) content, is associated with a lower risk of cardiovascular disease and diabetes. This in vitro study determined the effect of individual fatty acids (FA) found in dairy, and FA mixtures representative of a high SFA and a low SFA dairy lipid on markers of endothelial function in healthy and type II diabetic aortic endothelial cells. Methods Cells were incubated for 24 h with FA mixtures (400 μM) and individual FA: oleic acid (OA; 150 μM); palmitic acid (PA; 150 μM); stearic acid (SA: 40 μM); trans-palmitelaidic acid ( trans-PA; 20 μM); trans-vaccenic acid ( trans-VA; 20 μM); α-linolenic acid (ALA; 20 μM) and linoleic acid (LA; 20 μM). Cellular adhesion molecules (sICAM-1, sVCAM-1 and sE-selectin) and nitric oxide (NO) were measured using ELISA and a chemiluminescent-based assay, respectively. Relative gene expression of these markers, including the insulin receptor, was performed using real-time PCR as well as FA compositions of cell pellets by gas chromatography. Results FA mixtures affected sE-selectin concentrations ( P = 0.008), with concentrations lower following the high SFA compared to the low SFA mixture ( P = 0.004), while NO concentrations were higher in diabetic compared to healthy cells ( P = 0.029). Individual FA affected NO ( P = 0.007) and sE-selectin ( P = 0.040) concentrations with an increase following PA incubation relative to all other FA treatments ( P < 0.05). PA increased sE-selectin compared with other FA treatments ( P < 0.05). sE-selectin concentrations were also higher in healthy compared to diabetic cells ( P = 0.023). Expression of ICAM-1 and insulin receptor was up-regulated in healthy compared to diabetic cells ( P = 0.014 and P = 0.006 respectively). Conclusions Healthy and type II diabetic cells respond differently to incubation with FA treatments. Overall, physiological concentrations of dairy FA, but not dairy FA mixtures, substantially affected markers of endothelial function.