In Vivo Magnetic Resonance Imaging‐Based Detection of Heterogeneous Endothelial Response in Thoracic and Abdominal Aorta to Short‐Term High‐Fat Diet Ascribed to Differences in Perivascular Adipose Tissue in Mice

BACKGROUND: Long‐term feeding with a high‐fat diet (HFD) induces endothelial dysfunction in mice, but early HFD‐induced effects on endothelium have not been well characterized. METHODS AND RESULTS: Using an magnetic resonance imaging‐based methodology that allows characterization of endothelial function in vivo, we demonstrated that short‐term (2 weeks) feeding with a HFD to C57BL/6 mice or to E3L.CETP mice resulted in the impairment of acetylcholine‐induced response in the abdominal aorta (AA), whereas, in the thoracic aorta (TA), the acetylcholine‐induced response was largely preserved. Similarly, HFD resulted in arterial stiffness in the AA, but not in the TA. The difference in HFD‐induced response was ascribed to distinct characteristics of perivascular adipose tissue in the TA and AA, related to brown‐ and white‐like adipose tissue, respectively, as assessed by histology, immunohistochemistry, and Raman spectroscopy. In contrast, short‐term HFD‐induced endothelial dysfunction could not be linked to systemic insulin resistance, changes in plasma concentration of nitrite, or concentration of biomarkers of glycocalyx disruption (syndecan‐1 and endocan), endothelial inflammation (soluble form of vascular cell adhesion molecule 1, soluble form of intercellular adhesion molecule 1 and soluble form of E‐selectin), endothelial permeability (soluble form of fms‐like tyrosine kinase 1 and angiopoietin 2), and hemostasis (tissue plasminogen activator and plasminogen activator inhibitor 1). CONCLUSIONS: Short‐term feeding with a HFD induces endothelial dysfunction in the AA but not in the TA, which could be ascribed to a differential response of perivascular adipose tissue to a HFD in the AA versus TA. Importantly, early endothelial dysfunction in the AA is not linked to elevation of classical systemic biomarkers of endothelial dysfunction.