All-Trans Retinoic Acid Prevented Vein Grafts Stenosis by Inhibiting Rb-E2F Mediated Cell Cycle Progression and KLF5-RARα Interaction in Human Vein Smooth Muscle Cells

The Effect of Retinoids in Vascular Smooth Muscle Cells: From Phenotyping Switching to Proliferation and Migration

Atherosclerosis, a term derived from the Greek "athero" (atheroma) and "sclerosis" (hardening), is a long-standing process that leads to the formation of atheromatous plaques in the arterial wall, contributing to the development of atherosclerotic cardiovascular disease. The proliferation and migration of vascular smooth muscle cells (VSMCs) and the switching of their phenotype play a crucial role in the whole process. Retinoic acid (RA), a natural derivative of vitamin A, has been used in the treatment of various inflammatory diseases and cell proliferation disorders. Numerous studies have demonstrated that RA has an important inhibitory effect on the proliferation, migration, and dedifferentiation of vascular smooth muscle cells, leading to a significant reduction in atherosclerotic lesions. In this review article, we explore the effects of RA on the pathogenesis of atherosclerosis, focusing on its regulatory action in VSMCs and its role in the phenotypic switching, proliferation, and migration of VSMCs. Despite the potential impact that RA may have on the process of atherosclerosis, further studies are required to examine its safety and efficacy in clinical practice.

Is it time for a retinoic acid-eluting stent or retinoic acid-coated balloon? Insights from experimental studies of systemic and local delivery of retinoids

Although the incidence of restenosis and stent thrombosis has substantially declined during the last decades, they still constitute the two major causes of stent failure. These complications are partially attributed to the currently used cytostatic drugs, which can cause local inflammation, delay or prevent re-endothelialization and essentially cause arterial cell toxicity. Retinoic acid (RA), a vitamin A (retinol) derivative, is a naturally occurring substance used for the treatment of cell proliferation disorders. The agent has pleiotropic effects on vascular smooth muscle cells and macrophages: it influences the proliferation, migration, and transition of smooth muscle cells to other cell types and modulates macrophage activation. These observations are supported by accumulated evidence from in vitro and in vivo experiments. In addition, systemic and topical administration of RA can decrease the development of atherosclerotic plaques and reduce or inhibit restenosis after vascular injury (caused by embolectomy, balloon catheters, or ligation of arteries) in various experimental models. Recently, an RA-drug eluting stent (DES) has been tested in an animal model. In this review, we explore the effects of RA in atherosclerosis and the potential of the local delivery of RA through an RA-DES or RA-coated balloon for targeted therapeutic percutaneous vascular interventions. Despite promising published results, further experimental study is warranted to examine the safety and efficacy of RA-eluting devices in vascular artery disease.

All-Trans Retinoic Acid Promotes a Tumor Suppressive OTUD6B-β-TrCP-SNAIL Axis in Esophageal Squamous Cell Carcinoma and Enhances Immunotherapy

β-TrCP is an E3 ubiquitin ligase that plays important roles in multiple human cancers including esophageal squamous cell carcinoma (ESCC). Analysis of ESCC patient samples reveal that only protein level but not transcript level of β-TrCP associated with patient prognosis, suggesting regulators of β-TrCP protein stability play an essential role in ESCC progression and may be novel targets to develop ESCC therapies. Although β-TrCP stability is known to be mediated by the ubiquitin-proteasome system, it is unclear which enzymes play a major role to determine β-TrCP stability in the context of ESCC. In this study, OTUD6B is identified as a potent deubiquitinase of β-TrCP that suppress ESCC progression through the OTUD6B-β-TrCP-SNAIL axis. Low OTUD6B expression is associated with a poor prognosis of ESCC patients. Importantly, all-trans retinoic acid (ATRA) is found to promote OTUD6B translation and thus suppress ESCC tumor growth and enhance the response of ESCC tumors to anti-PD-1 immunotherapies. These findings demonstrate that OTUD6B is a crucial deubiquitinase of β-TrCP in ESCC and suggest combination of ATRA and anti-PD-1 immune checkpoint inhibitor may benefit a cohort of ESCC patients.

Histopathological evaluation of a retinoic acid eluting stent in a rabbit iliac artery model

This study aimed to evaluate the safety and efficacy of innovative retinoic acid (RA) eluting stents with bioabsorbable polymer. Sixty stents divided in ten groups were implanted in the iliac arteries of 30 rabbits. Two polymers ("A", poly (lactic-co-glycolic acid) and "B", polylactic acid), and three doses ("Low", "Medium" and "High") of RA (groups: AL, AM, AH, BL, BM, BH) were used on cobalt chromium stents (Rontis Corporation), one group of bare stent (C), one group (D) of Everolimus eluting stent (Xience-Pro, Abbot Vascular), and two groups of Rontis Everolimus eluting stents coated with polymer A (EA) and B (EB). Treated arteries were explanted after 4 weeks, processed by methyl methacrylate resin and evaluated by histopathology. None of the implanted stents was related with thrombus formation or extensive inflammation. Image analysis showed limited differences between groups regarding area stenosis (BH, D and EB groups had the lower values). Group BH had lower intimal mean thickness than AH (105.1 vs 75.3 μm, p = 0.024). Stents eluting RA, a non-cytotoxic drug, were not related with thrombus formation and had an acceptable degree of stenosis 4 weeks post implantation. RA dose and type of polymer may play role in the biocompatibility of the stents.

Potential Therapeutic Effect of All-Trans Retinoic Acid on Atherosclerosis

Atherosclerosis is a major risk factor for myocardial infarction and ischemic stroke, which are the leading cause of death worldwide. All-trans retinoic acid (ATRA) is a natural derivative of essential vitamin A. Numerous studies have shown that ATRA plays an important role in cell proliferation, cell apoptosis, cell differentiation, and embryonic development. All-trans retinoic acid (ATRA) is a ligand of retinoic acid receptors that regulates various biological processes by activating retinoic acid signals. In this paper, the metabolic processes of ATRA were reviewed, with emphasis on the effects of ATRA on inflammatory cells involved in the process of atherosclerosis.

All trans retinoic acid alleviates coronary stenosis by regulating smooth muscle cell function in a mouse model of Kawasaki disease

Coronary artery (CA) stenosis is a detrimental and often life-threatening sequela in Kawasaki disease (KD) patients with coronary artery aneurysm (CAA). Therapeutic strategies for these patients have not yet been established. All-trans-retinoic acid (atRA) is a modulator of smooth muscle cell functions. The purpose of this study was to investigate the effect of atRA on CA stenosis in a mouse model of KD. Lactobacillus casei cell wall extract (LCWE) was intraperitoneally injected into 5-week-old male C57BL/6 J mice to induce CA stenosis. Two weeks later, the mice were orally administered atRA (30 mg/kg) 5 days per week for 14 weeks (LCWE + atRA group, n = 7). Mice in the untreated group (LCWE group, n = 6) received corn oil alone. Control mice were injected with phosphate-buffered saline (PBS, n = 5). Treatment with atRA significantly suppressed CA inflammation (19.3 ± 2.8 vs 4.4 ± 2.8, p < 0.0001) and reduced the incidence of CA stenosis (100% vs 18.5%, p < 0.05). In addition, atRA suppressed the migration of human coronary artery smooth muscle cells (HCASMCs) induced by platelet-derived growth factor subunit B homodimer (PDGF-BB). In conclusion, atRA dramatically alleviated CA stenosis by suppressing SMC migration. Therefore, it is expected to have clinical applications preventing CA stenosis in KD patients with CAA.