Figure 4.

Invasive and non‐invasive methods for the determination of endothelial function. (A) Acetylcholine (ACh)‐dependent vasoreactivity of coronary vessels caused by intra‐coronary (i.c.) ACh infusion. Vasodilatation and stenotic areas are monitored by angiographic imaging and Doppler ultrasound (blood flow). (B) ACh‐dependent vasoreactivity of capacity vessels of the forearm upon intra‐arterial ACh infusion. Vasodilatation is recorded by Doppler ultrasound (diameter and blood flow). (C) Flow‐mediated dilation (FMD) of capacity vessels of the forearm (brachial artery) upon occlusion/ischaemia and reperfusion/hyperaemia. Vasodilatation is recorded by Doppler ultrasound (diameter and blood flow). Maximal vasoreactivity/dilation is determined by sublingual administration of nitroglycerin (NTG). Adapted from (Munzel, 2008). With permission of Georg Thieme Verlag KG Stuttgart. Copyright © 2008, Rights Managed by Georg Thieme Verlag KG Stuttgart • New York. All rights reserved. (D) Peripheral arterial tonometry measures volume changes and pulse waves by a finger probe. Additional details for the determination of pulse wave velocity (PWV) are explained in the text. (E) Ultrasound‐based detection of microbubbles released from nanocarriers upon chemical reaction with ROS or upon destruction of the carriers by ultrasound. The nanocarriers are targeted to damaged endothelium (e.g. by bound antibodies). The released microbubbles are detected by ultrasound. (F) L‐band electron paramagnetic resonance (EPR) spectroscopy can be used for the detection of paramagnetic compounds or particles (usually having an unpaired electron) in whole animals and tissues. Damaged vasculature can be labelled by antibodies linked to iron oxide (EPR active). Likewise, heparin‐bound spin traps are bound to the endothelial surface and allow the detection of nitric oxide or ROS.