Quantitative and qualitative features of carotid and coronary atherosclerotic plaque among men and women

Compositional plaque progression in women and men with non-obstructive coronary artery disease

Background

In coronary artery disease (CAD), plaque progression and plaque composition are associated with cardiovascular risk. Whether compositional plaque progression in non-obstructive CAD differs between women and men is less studied.

Methods

We included 31 patients (42% women) with chronic non-obstructive CAD from the Norwegian Registry of Invasive Cardiology, undergoing serial coronary computed tomography angiography (CCTA) on clinical indication (median inter-scan interval 1.8 [1.5-2.2] years). We performed quantitative and qualitative plaque analysis of all coronary artery segments.

Results

Women were older compared to men (65 ± 8 years vs. 55 ± 12 years, p = 0.019), while there was no difference in the prevalence of hypertension, diabetes, smoking or statin treatment between groups. At baseline, women had a higher total plaque burden, more calcified plaques, and less fibro-fatty and necrotic core plaques compared to men (all p < 0.05). During follow-up, men showed faster progression of fibro-fatty plaques (4.0 ± 5.4 % per year vs. -0.6 ± 3.1 % per year, p = 0.019) and a greater reduction of fibrous plaques (-7.3 ± 6.1 % per year vs. 2.1 ± 7.2 % per year, p = 0.003) compared to women even after age adjustment. At follow-up, total plaque burden remained higher in women compared to men (24.9 ± 3.3 % vs. 21.1 ± 2.6 %, p = 0.001), while men had an increase in fibro-fatty (21.2 ± 9.3 % vs. 28.6 ± 9.8 %, p = 0.004) and necrotic core plaques (5.6 ± 3.6 % vs. 10.8 ± 7.2 %, p = 0.006), and a decrease in fibrous plaques (69.0 ± 11.9 % vs. 54.7 ± 13.7 %, p < 0.001). Women's plaque composition remained unaltered.

Conclusion

In non-obstructive CAD, serial CCTA demonstrated a higher total plaque burden and a stable plaque composition in women, while men had a faster progression of unstable low-attenuating fibro-fatty plaques.Clinical trial registration: ClinicalTrials.gov: Identifier NCT04009421.

Sirolimus-loaded exosomes as a promising vascular delivery system for the prevention of post-angioplasty restenosis

Restenosis remains the main reason for treatment failure of arterial disease. Sirolimus (SIR) as a potent anti-proliferative agent is believed to prevent the phenomenon. The application of exosomes provides an extended-release delivery platform for SIR intramural administration. Herein, SIR was loaded into fibroblast-derived exosomes isolated by ultracentrifugation. Different parameters affecting drug loading were optimized, and exosome samples were characterized regarding physicochemical, pharmaceutical, and biological properties. Cytotoxicity, scratch wound assays, and quantitative real-time PCR for inflammation- and migration-associated genes were performed. Restenosis was induced by carotid injury in a rat carotid model and then exosomes were locally administered. After 14 days, animals were investigated by computed tomography (CT) angiography, morphometric, and immunohistochemical analyses. Western blotting confirmed the presence of specific protein markers in exosomes. Characterization of empty and SIR-loaded exosomes verified round and nanoscale structure of vesicles. Among prepared formulations, desired entrapment efficiency (EE) of 76% was achieved by protein:drug proportion of 2:1 and simple incubation for 30 min at 37 °C. Also, the optimal formulation released about 30% of the drug content during the first 24 h, followed by a prolonged release for several days. In vitro studies revealed the uptake and functional efficacy of the optimized formulation. In vivo studies revealed that %restenosis was in the following order: saline > empty exosomes > SIR-loaded exosomes. Furthermore, Ki67, alpha smooth muscle actin (α-SMA), and matrix metalloproteinase (MMP) markers were less expressed in the SIR-exosomes-treated arteries. These findings confirmed that exosomal SIR could be a hopeful strategy for the prevention of restenosis.

Deep Learning Paradigm and Its Bias for Coronary Artery Wall Segmentation in Intravascular Ultrasound Scans: A Closer Look

BACKGROUND AND MOTIVATION

Coronary artery disease (CAD) has the highest mortality rate; therefore, its diagnosis is vital. Intravascular ultrasound (IVUS) is a high-resolution imaging solution that can image coronary arteries, but the diagnosis software via wall segmentation and quantification has been evolving. In this study, a deep learning (DL) paradigm was explored along with its bias.

METHODS

Using a PRISMA model, 145 best UNet-based and non-UNet-based methods for wall segmentation were selected and analyzed for their characteristics and scientific and clinical validation. This study computed the coronary wall thickness by estimating the inner and outer borders of the coronary artery IVUS cross-sectional scans. Further, the review explored the bias in the DL system for the first time when it comes to wall segmentation in IVUS scans. Three bias methods, namely (i) ranking, (ii) radial, and (iii) regional area, were applied and compared using a Venn diagram. Finally, the study presented explainable AI (XAI) paradigms in the DL framework.

FINDINGS AND CONCLUSIONS

UNet provides a powerful paradigm for the segmentation of coronary walls in IVUS scans due to its ability to extract automated features at different scales in encoders, reconstruct the segmented image using decoders, and embed the variants in skip connections. Most of the research was hampered by a lack of motivation for XAI and pruned AI (PAI) models. None of the UNet models met the criteria for bias-free design. For clinical assessment and settings, it is necessary to move from a paper-to-practice approach.

Engineering molecular nanoprobes to target early atherosclerosis: Precise diagnostic tools and promising therapeutic carriers

Atherosclerosis, an inflammation-driven chronic blood vessel disease, is a major contributor to devastating cardiovascular events, bringing serious social and economic burdens. Currently, non-invasive diagnostic and therapeutic techniques in combination with novel nanosized materials as well as established molecular targets are under active investigation to develop integrated molecular imaging approaches, precisely visualizing and/or even effectively reversing early-stage plaques. Besides, mechanistic investigation in the past decades provides many potent candidates extensively involved in the initiation and progression of atherosclerosis. Recent hotly-studied imaging nanoprobes for detecting early plaques mainly including optical nanoprobes, photoacoustic nanoprobes, magnetic resonance nanoprobes, positron emission tomography nanoprobes, and other dual- and multi-modality imaging nanoprobes, have been proven to be surface functionalized with important molecular targets, which occupy tailored physical and biological properties for atherogenesis. Of note, these engineering nanoprobes provide long blood-pool residence and specific molecular targeting, which allows efficient recognition of early-stage atherosclerotic plaques and thereby function as a novel type of precise diagnostic tools as well as potential therapeutic carriers of anti-atherosclerosis drugs. There have been no available nanoprobes applied in the clinics so far, although many newly emerged nanoprobes, as exemplified by aggregation-induced emission nanoprobes and TiO₂ nanoprobes, have been tested for cell lines in vitro and atherogenic animal models in vivo, achieving good experimental effects. Therefore, there is an urgent call to translate these preclinical results for nanoprobes into clinical trials. For this reason, this review aims to give an overview of currently investigated nanoprobes in the context of atherosclerosis, summarize relevant published studies showing applications of different kinds of formulated nanoprobes in early detection and reverse of plaques, discuss recent advances and some limitations thereof, and provide some insights into the development of the new generation of more precise and efficient molecular nanoprobes, with a critical property of specifically targeting early atherosclerosis.