Noninvasive Molecular Ultrasound Monitoring of Vessel Healing After Intravascular Surgical Procedures in a Preclinical Setup

Abstract

Objective— Cardiovascular interventions induce damage to the vessel wall making antithrombotic therapy inevitable until complete endothelial recovery. Without a method to accurately determine the endothelial status, many patients undergo prolonged anticoagulation therapy, denying them any invasive medical procedures, such as surgical operations and dental interventions. Therefore, we aim to introduce molecular ultrasound imaging of the vascular cell adhesion molecule (VCAM)-1 using targeted poly- n -butylcyanoacrylate microbubbles (MB VCAM-1 ) as an easy accessible method to monitor accurately the reendothelialization of vessels. Approach and Results— ApoE −/− mice were fed with an atherogenic diet for 1 and 12 weeks and subsequently, endothelial denudation was performed in the carotid arteries using a guidewire. Molecular ultrasound imaging was performed at different time points after denudation (1, 3, 7, and 14 days). An increased MB VCAM-1 binding after 1 day, a peak after 3 days, and a decrease after 7 days was found. After 12 weeks of diet, MB VCAM-1 binding also peaked after 3 days but remained high until 7 days, indicating a delay in endothelial recovery. Two-photon laser scanning microscopy imaging of double fluorescence staining confirmed the exposure of VCAM-1 on the superficial layer after arterial injury only during the healing phase. After complete reendothelialization, VCAM-1 expression persisted in the subendothelial layer but was not reachable for the MB VCAM-1 anymore. Conclusion— Molecular ultrasound imaging with MB VCAM-1 is promising to assess vascular damage and to monitor endothelial recovery after arterial interventions. Thus, it may become an important diagnostic tool supporting the development of adequate therapeutic strategies to personalize anticoagulant and anti-inflammatory therapy after cardiovascular intervention.

Noninvasive in vivo Assessment of the Re‐endothelialization Process Using Ultrasound Biomicroscopy in the Rat Carotid Artery Balloon Injury Model

“…Compared with other modalities, acquisition of UBM images is time efficient and does not need to use contrast agents . Another advantage is the real‐time in vivo acquisition of detailed morphologic and physiologic data, which can be processed further with advanced software.…”

“…New methods for the in vivo visualization of arterial wall healing have been reported; these have targeted the increased vascular permeability in areas lacking an intact endothelium using contrast‐enhanced magnetic resonance imaging . Contrast‐enhanced ultrasound (US) has also been used to visualize the arterial healing process by targeting specific molecules in activated endothelial cells and vascular smooth muscle cells, such as α v β 3 ‐integrin and vascular cell adhesion molecule‐1 . However, all of these methods share the same limitation of being dependent on vascular access or the use of contrast agents.…”

Ultrasonic Perfluorohexane‐Loaded Monocyte Imaging: Toward a Minimally Invasive Technique for Selective Detection of Liver Inflammation in Fatty Liver Disease

“…In future experiments, adhesion molecule expression on the endothelium could be assessed by immunofluorescence imaging. With the use of 2‐photon laser‐scanning microscopy, it should be (after staining and fixation) possible to identify the endothelial/vascular aspect in 3 dimensions in intact liver tissue and assess the presence and density of adhesion molecules, such as ICAM‐1 and VCAM‐1 …”

“…With the use of 2-photon laser-scanning microscopy, it should be (after staining and fixation) possible to identify the endothelial/vascular aspect in 3 dimensions in intact liver tissue and assess the presence and density of adhesion molecules, such as ICAM-1 and VCAM-1. 31 Lastly, we did not assess liver tissue damage due to administration of the PFH-loaded macrophage suspension. Dirven et al 14 reported liver lesions on microbubble administration, but only after 3 hours.…”

Cardiovascular Immunotherapy and the Role of Imaging

“…Compared to other available anatomic imaging methods such as ultrasound, 74 magnetic resonance (MR) or computed tomography, PET imaging 75–77 has the advantageous ability to visualize minuscule concentrations of tracers that target specific molecular process. PET vascular inflammation imaging with fluorodeoxyglucose (FDG) has become important in atherosclerosis research, 78 owing to FDG's accumulation in cells with glycolytic rate.…”