Effects of an alpha-4 integrin inhibitor on restenosis in a new porcine model combining endothelial denudation and stent placement

A novel method to detect carotid artery in-stent restenosis

BACKGROUND AND PURPOSE

Carotid artery stenosis is a major risk factor for ischemic stroke. Despite carotid artery stenting, in-stent restenosis (ISR) remains challenging. Pigs serve as an ideal ISR model. This study aims to establish a novel porcine model of carotid ISR using open-loop and closed-loop stents and to assess ISR with optical coherence tomography (OCT) and histopathology, comparing incidence and vascular response between stent types.

METHODS

Twelve adult male Bama miniature pigs underwent carotid stenting with either open-loop or closed-loop stents. The animals received antiplatelet therapy pre- and postimplantation. Postimplantation evaluations at 90 days included carotid digital subtraction angiography (DSA), OCT, histopathological examination, and electron microscopy.

RESULTS

Both stent types showed ISR as detected by OCT and DSA. OCT revealed comparable neointimal proliferation within stent struts for both types, with no significant differences in stent, lumen, and neointimal dimensions. Histopathological analysis and electron microscopy provided insights into tissue responses and healing processes following stent implantation. No significant difference in ISR incidence was found between the stent types based on a χ2 test (p = .110). OCT and hematoxylin-eosin staining exhibit the highest consistency in evaluating neointimal area.

CONCLUSIONS

The novel porcine ISR model demonstrated similar ISR outcomes for open-loop and closed-loop stents. OCT proved to be a highly consistent and valuable tool for evaluating stent and arterial conditions, comparable to histopathological findings. However, due to a small sample size, the validity of these preliminary findings requires further investigation to be confirmed.

Roles of Integrin in Cardiovascular Diseases: From Basic Research to Clinical Implications

Cardiovascular diseases (CVDs) pose a significant global health threat due to their complex pathogenesis and high incidence, imposing a substantial burden on global healthcare systems. Integrins, a group of heterodimers consisting of α and β subunits that are located on the cell membrane, have emerged as key players in mediating the occurrence and progression of CVDs by regulating the physiological activities of endothelial cells, vascular smooth muscle cells, platelets, fibroblasts, cardiomyocytes, and various immune cells. The crucial role of integrins in the progression of CVDs has valuable implications for targeted therapies. In this context, the development and application of various integrin antibodies and antagonists have been explored for antiplatelet therapy and anti-inflammatory-mediated tissue damage. Additionally, the rise of nanomedicine has enhanced the specificity and bioavailability of precision therapy targeting integrins. Nevertheless, the complexity of the pathogenesis of CVDs presents tremendous challenges for monoclonal targeted treatment. This paper reviews the mechanisms of integrins in the development of atherosclerosis, cardiac fibrosis, hypertension, and arrhythmias, which may pave the way for future innovations in the diagnosis and treatment of CVDs.

Role of Integrins in Modulating Smooth Muscle Cell Plasticity and Vascular Remodeling: From Expression to Therapeutic Implications

Smooth muscle cells (SMCs), present in the media layer of blood vessels, are crucial in maintaining vascular homeostasis. Upon vascular injury, SMCs show a high degree of plasticity, undergo a change from a “contractile” to a “synthetic” phenotype, and play an essential role in the pathophysiology of diseases including atherosclerosis and restenosis. Integrins are cell surface receptors, which are involved in cell-to-cell binding and cell-to-extracellular-matrix interactions. By binding to extracellular matrix components, integrins trigger intracellular signaling and regulate several of the SMC function, including proliferation, migration, and phenotypic switching. Although pharmacological approaches, including antibodies and synthetic peptides, have been effectively utilized to target integrins to limit atherosclerosis and restenosis, none has been commercialized yet. A clear understanding of how integrins modulate SMC biology is essential to facilitate the development of integrin-based interventions to combat atherosclerosis and restenosis. Herein, we highlight the importance of integrins in modulating functional properties of SMCs and their implications for vascular pathology.

Novel potential targets for prevention of arterial restenosis: insights from the pre-clinical research

Restenosis is the pathophysiological process occurring in 10-15% of patients submitted to revascularization procedures of coronary, carotid and peripheral arteries. It can be considered as an excessive healing reaction of the vascular wall subjected to arterial/venous bypass graft interposition, endarterectomy or angioplasty. The advent of bare metal stents, drug-eluting stents and of the more recent drug-eluting balloons, have significantly reduced, but not eliminated, the incidence of restenosis, which remains a clinically relevant problem. Biomedical research in pre-clinical animal models of (re)stenosis, despite its limitations, has contributed enormously to the identification of processes involved in restenosis progression, going well beyond the initial dogma of a primarily proliferative disease. Although the main molecular and cellular mechanisms underlying restenosis have been well described, new signalling molecules and cell types controlling the progress of restenosis are continuously being discovered. In particular, microRNAs and vascular progenitor cells have recently been shown to play a key role in this pathophysiological process. In addition, the advanced highly sensitive high-throughput analyses of molecular alterations at the transcriptome, proteome and metabolome levels occurring in injured vessels in animal models of disease and in human specimens serve as a basis to identify novel potential therapeutic targets for restenosis. Molecular analyses are also contributing to the identification of reliable circulating biomarkers predictive of post-interventional restenosis in patients, which could be potentially helpful in the establishment of an early diagnosis and therapy. The present review summarizes the most recent and promising therapeutic strategies identified in experimental models of (re)stenosis and potentially translatable to patients subjected to revascularization procedures.