Association of circulating Notch1 and VEGF with flow-mediated dilation and aerobic fitness in healthy adults.

Notch1 is a mechanosensitive endothelial receptor that responds to vascular wall shear stress. However, data on Notch1 activity in humans remains limited, particularly regarding its role in endothelial function. OBJECTIVES: Accordingly, the purpose of this study was to determine whether Notch1 is associated with the flow-mediated dilatory (FMD) response and whether it is related to aerobic fitness. A secondary purpose was to determine whether Notch1 is related to concentrations of vascular endothelial growth factor (VEGF). METHODS: Sixteen (8M/8F) young (20-30 yrs old) and healthy (BMI: 25 ± 4.2 kg/m(2), blood pressure: 117 ± 11.63/69 ± 11.25 mmHg) adults participated in the study. Aerobic fitness was determined by cycle V̇O(2) peak. An FMD was performed on the brachial artery, and blood samples were taken from an antecubital vein at rest (baseline) and 1 min after cuff deflation (to align with peak vessel dilation). Concentrations of Notch1 extracellular domain (NECD) and VEGF were determined from plasma using enzyme-linked immunosorbent assays. RESULTS: In contrast to our hypothesis, concentrations of NECD and VEGF did not change throughout the FMD and were unrelated to allometrically scaled FMD values (p all>0.05). Likewise, there was no relationship between changes in NECD and VEGF (p=0.331, r=0.127). However, the change in NECD across the FMD was moderately (r=0.515) and significantly (p=0.024) correlated with V̇O(2) peak. CONCLUSIONS: These novel data indicate that in healthy young adults, Notch1 activity is linked to aerobic fitness but may not be acutely involved in the shear-mediated vasodilatory response.