Imaging of Dysfunctional Elastogenesis in Atherosclerosis Using an Improved Gadolinium-Based Tetrameric MRI Probe Targeted to Tropoelastin

Fluorescence and photoacoustic (FL/PA) dual-modal probe: Responsive to reactive oxygen species (ROS) for atherosclerotic plaque imaging

Accurate and early detection of atherosclerosis (AS) is imperative for their effective treatment. However, fluorescence probes for efficient diagnosis of AS often encounter insufficient deep tissue penetration, which hinders the reliable assessment of plaque vulnerability. In this work, a reactive oxygen species (ROS) activated near-infrared (NIR) fluorescence and photoacoustic (FL/PA) dual model probe TPA-QO-B is developed by conjugating two chromophores (TPA-QI and O-OH) and ROS-specific group phenylboronic acid ester. The incorporation of ROS-specific group not only induces blue shift in absorbance, but also inhibits the ICT process of TPA-QO-OH, resulting an ignorable initial FL/PA signal. ROS triggers the convertion of TPA-QO-B to TPA-QO-OH, resulting in the concurrent amplification of FL/PA signal. The exceptional selectivity of TPA-QO-B towards ROS makes it effectively distinguish AS mice from the healthy. The NIR emission can achieve a tissue penetration imaging depth of 0.3 cm. Moreover, its PA775 signal possesses the capability to penetrate tissues up to a thickness of 0.8 cm, ensuring deep in vivo imaging of AS model mice in early stage. The ROS-triggered FL/PA dual signal amplification strategy improves the accuracy and addresses the deep tissue penetration problem simultaneously, providing a promising tool for in vivo tracking biomarkers in life science and preclinical applications.

Non-invasive in vivo imaging of changes in Collagen III turnover in myocardial fibrosis

Heart failure (HF) affects 64 million people globally with enormous societal and healthcare costs. Myocardial fibrosis, characterised by changes in collagen content drives HF. Despite evidence that collagen type III (COL3) content changes during myocardial fibrosis, in vivo imaging of COL3 has not been achieved. Here, we discovered the first imaging probe that binds to COL3 with high affinity and specificity, by screening candidate peptide-based probes. Characterisation of the probe showed favourable magnetic and biodistribution properties. The probe's potential for in vivo molecular cardiac magnetic resonance imaging was evaluated in a murine model of myocardial infarction. Using the new probe, we were able to map and quantify, previously undetectable, spatiotemporal changes in COL3 after myocardial infarction and monitor response to treatment. This innovative probe provides a promising tool to non-invasively study the unexplored roles of COL3 in cardiac fibrosis and other cardiovascular conditions marked by changes in COL3.

Nanomedicine for Diagnosis and Treatment of Atherosclerosis

With the changing disease spectrum, atherosclerosis has become increasingly prevalent worldwide and the associated diseases have emerged as the leading cause of death. Due to their fascinating physical, chemical, and biological characteristics, nanomaterials are regarded as a promising tool to tackle enormous challenges in medicine. The emerging discipline of nanomedicine has filled a huge application gap in the atherosclerotic field, ushering a new generation of diagnosis and treatment strategies. Herein, based on the essential pathogenic contributors of atherogenesis, as well as the distinct composition/structural characteristics, synthesis strategies, and surface design of nanoplatforms, the three major application branches (nanodiagnosis, nanotherapy, and nanotheranostic) of nanomedicine in atherosclerosis are elaborated. Then, state-of-art studies containing a sequence of representative and significant achievements are summarized in detail with an emphasis on the intrinsic interaction/relationship between nanomedicines and atherosclerosis. Particularly, attention is paid to the biosafety of nanomedicines, which aims to pave the way for future clinical translation of this burgeoning field. Finally, this comprehensive review is concluded by proposing unresolved key scientific issues and sharing the vision and expectation for the future, fully elucidating the closed loop from atherogenesis to the application paradigm of nanomedicines for advancing the early achievement of clinical applications.