The following is a summary of “Impact of Free Fatty Acids on Vascular Insulin Responses Across the Arterial Tree: A Randomized Crossover Study,” published in the April 2024 issue of Endocrinology by Love, et al.

Vascular insulin resistance is common in obesity and diabetes, but the exact impact of insulin across different arteries and the connection between insulin responses in various arterial regions remain unclear. For a study, researchers sought to explore how elevated levels of free fatty acids (FFAs) affect insulin action in different parts of the arterial system and to understand how these insulin responses relate to each other.

They conducted a randomized crossover trial involving healthy lean adults who underwent euglycemic insulin clamp procedures with either lipid or saline infusions. They measured various vascular parameters before and after the insulin clamp, including arterial blood pressure, brachial artery flow-mediated dilation (FMD), carotid-femoral pulse wave velocity (cfPWV), augmentation index (AIx), pulse wave separation analysis, subendocardial viability ratio (SEVR), and microvascular blood flow in skeletal and cardiac muscle. They also calculated insulin-mediated glucose disposal.

The results showed that insulin improved artery dilation, pulse wave characteristics, and microvascular blood flow in both cardiac and skeletal muscle. However, when plasma FFA levels were elevated to mimic those seen in insulin-resistant individuals, arterial health deteriorated, and insulin’s positive effects were blunted. Additionally, the study found that insulin-mediated blood flow in muscle microvasculature was closely linked to artery dilation and pulse wave velocity, which are important indicators of cardiovascular health.

Overall, the findings suggested that high levels of FFAs can lead to widespread arterial insulin resistance, and interventions targeting FFA-related vascular insulin resistance may be beneficial for preventing cardiovascular disease.

Reference: academic.oup.com/jcem/article-abstract/109/4/1041/7407978