The generation of reactive oxygen species (ROS) and an imbalance of antioxidant defence mechanisms can result in oxidative stress. Several pro-atherogenic stimuli that promote intimal-medial thickening (IMT) and early arteriosclerotic disease progression share oxidative stress as a common regulatory pathway dictating vascular cell fate. The major source of ROS generated within the vascular system is the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes (Nox), of which seven members have been characterized. The Nox family are critical determinants of the redox state within the vessel wall that dictate, in part the pathophysiology of several vascular phenotypes. This review highlights the putative role of ROS in controlling vascular fate by promoting endothelial dysfunction, altering vascular smooth muscle phenotype and dictating resident vascular stem cell fate, all of which contribute to intimal medial thickening and vascular disease progression.

Arteriosclerosis causes significant morbidity and mortality worldwide. Central to this process is the development of subclinical non-atherosclerotic intimal lesions before the appearance of pathologic intimal thickening and advanced atherosclerotic plaques. Intimal thickening is associated with several risk factors, including oxidative stress due to reactive oxygen species (ROS), inflammatory cytokines and lipid. The main ROS producing systems in-vivo are reduced nicotinamide dinucleotide phosphate (NADPH) oxidase (NOX). ROS effects are context specific. Exogenous ROS induces apoptosis and senescence, whereas intracellular ROS promotes stem cell differentiation, proliferation, and migration. Lineage tracing studies using murine models of subclinical atherosclerosis have revealed the contributory role of medial smooth muscle cells (SMCs), resident vascular stem cells, circulating bone-marrow progenitors and endothelial cells that undergo endothelial-mesenchymal-transition (EndMT). This review will address the putative physiological and patho-physiological roles of ROS in controlling vascular cell fate and ROS contribution to vascular regeneration and disease progression.

Background Cell and molecular mechanisms mediating the cardiovascular effects of alcohol are not fully understood. Our aim was to determine the effect of moderate Ethanol (EtOH) on Sonic Hedgehog (SHh) signaling in regulating possible Sca1+ progenitor stem cell involvement during pathologic arterial remodeling. Methods and Results Partial ligation or sham-operation of the left carotid artery was performed in transgenic Sca1-eGFP mice gavaged with or without ‘daily moderate’ EtOH. The EtOH group had reduced adventitial thickening and less neo-intimal formation, compared to ligated controls. There was expansion of eGFP expressing (i.e., Sca1+) cells in remodeled vessels post-ligation (14d), especially in the neo-intima. Ethanol treatment reduced the number of Sca1+ cells in ligated vessel cross-sections concomitant with diminished remodeling, compared to control ligated vessels. Moreover, EtOH attenuated SHh signaling in injured carotids as determined by immunohistochemical analysis of the target genes patched 1 (Ptch1) and Gli2, and RT-PCR of whole vessel Gli2 mRNA levels. Intraperitoneal injection of ligated Sca1 - eGFP mice with the SHh signaling inhibitor cyclopamine diminished hedgehog target gene expression, reduced the number of Sca1+ cells, and ameliorated carotid remodeling. EtOH treatment of purified Sca1+ adventitial progenitor stem cells in vitro inhibited SHh signaling, and their rSHh-induced differentiation to vascular smooth muscle cells. Conclusions EtOH reduces SHh - responsive Sca1+ progenitor cell myogenic differentiation/expansion in vitro and during arterial remodeling in response to ligation injury in vivo. Regulation of vascular Sca1+ progenitor cells in this way may be an important novel mechanism contributing to alcohol's cardiovascular protective effects.

The accumulation of vascular smooth muscle (SMC)-like cells and stem cell-derived myogenic and osteogenic progeny contributes significantly to arteriosclerotic disease. This study established whether label-free vibrational spectroscopy can discriminate de-differentiated 'synthetic' SMCs from undifferentiated stem cells and their myogenic and osteogenic progeny in vitro, compared with conventional immunocytochemical and genetic analyses. TGF-β1- and Jagged1-induced myogenic differentiation of CD44 mesenchymal stem cells was confirmed in vitro by immunocytochemical analysis of specific SMC differentiation marker expression (α-actin, calponin and myosin heavy chain 11), an epigenetic histone mark (H3K4me2) at the myosin heavy chain 11 locus, promoter transactivation and mRNA transcript levels. Osteogenic differentiation was confirmed by alizarin red staining of calcium deposition. Fourier Transform Infrared (FTIR) maps facilitated initial screening and discrimination while Raman spectroscopy of individual cell nuclei revealed specific spectral signatures of each cell type in vitro, using Principal Components Analysis (PCA). PCA fed Linear Discriminant Analysis (LDA) enabled quantification of this discrimination and the sensitivity and specificity value was determined for all cell populations based on a leave-one-out cross validation method and revealed that de-differentiated SMCs and stem-cell derived myogenic progeny in culture shared the greatest similarity. FTIR and Raman spectroscopy discriminated undifferentiated stem cells from both their myogenic and osteogenic progeny. The ability to detect stem cell-derived myogenic progeny using label-free platforms in situ may facilitate interrogation of these important phenotypes during vascular disease progression.

Arteriosclerosis is an important age-dependent disease that encompasses atherosclerosis, in-stent restenosis (ISR), pulmonary hypertension, autologous bypass grafting and transplant arteriosclerosis. Endothelial dysfunction and the proliferation of vascular smooth muscle cell (vSMC)-like cells is a critical event in the pathology of arteriosclerotic disease leading to intimal-medial thickening (IMT), lipid retention and vessel remodelling. An important aspect in guiding clinical decision-making is the detection of biomarkers of subclinical arteriosclerosis and early cardiovascular risk. Crucially, relevant biomarkers need to be good indicators of injury which change in their circulating concentrations or structure, signalling functional disturbances. Extracellular vesicles (EVs) are nanosized membraneous vesicles secreted by cells that contain numerous bioactive molecules and act as a means of intercellular communication between different cell populations to maintain tissue homeostasis, gene regulation in recipient cells and the adaptive response to stress. This review will focus on the emerging field of EV research in cardiovascular disease (CVD) and discuss how key EV signatures in liquid biopsies may act as early pathological indicators of adaptive lesion formation and arteriosclerotic disease progression. EV profiling has the potential to provide important clinical information to complement current cardiovascular diagnostic platforms that indicate or predict myocardial injury. Finally, the development of fitting devices to enable rapid and/or high-throughput exosomal analysis that require adapted processing procedures will be evaluated.