Low concentration of ethanol favors progenitor cell differentiation and neovascularization in high-fat diet-fed mice model

Endothelial Homeostasis Under the Influence of Alcohol-Relevance to Atherosclerotic Cardiovascular Disease

Alcohol, in the form of ethyl alcohol or ethanol, is a widely consumed substance with significant implications for human health. Research studies indicate multifaceted effects of alcohol on the cardiovascular system with both protective and harmful effects on atherosclerotic cardiovascular disease (ASCVD), depending on the amount involved and the pattern of consumption. Among the critical components of the cardiovascular system are endothelial cells which line blood vessels. These cells are pivotal in maintaining vessel homeostasis, regulating blood flow, and preventing thrombosis. Their compromised function correlates with arterial disease progression and is predictive of cardiovascular events. Here we review research investigating how alcohol exposure affects the endothelium to gain insight into potential mechanisms mediating alcohol's influence on ASCVD underlying heart attacks and strokes. Studies highlight opposite effects of low versus high levels of alcohol on many endothelial functions. In general, low-to-moderate levels of alcohol (~5-25 mM) maintain the endothelium in a non-activated state supporting vascular homeostasis, while higher alcohol levels (≥50 mM) lead to endothelial dysfunction and promotes atherosclerosis. These biphasic endothelial effects of alcohol might underlie the varying impacts of different alcohol consumption patterns on ASCVD.

Low Ethanol Concentrations Promote Endothelial Progenitor Cell Capacity and Reparative Function

Background

Endothelial progenitor cells (EPCs) are recruited to injured endothelium and contribute to its regeneration. There is evidence that moderate ethanol consumption prevents the development and progression of atherosclerosis in a variety of in vitro and in vivo models and increases the mobilization of progenitor cells. Furthermore, there are studies that identified ethanol at low concentration as a therapeutic tool to mobilize progenitor cells in peripheral blood. At the same time, the cell number of EPCs represents a close link to cardiovascular system constitution and function and contributes to cardiovascular risk. The aim of this study was to evaluate the effect of low dose ethanol on typical features of endothelial colony-forming cells (ECFCs), a proliferative subtype of EPCs.

Methods and Results

We tested whether ethanol impacts the functional abilities of ECFC (e.g., migration, tube formation, and proliferation) using in vitro assays, the intercommunication of ECFC by exploring cell surface molecules by flow cytometry, and the expression of (anti-)angiogenic molecules by ELISA. Low concentrations of ethanol concentration promoted migration, proliferation, and tubule formation of ECFC. The expression of the cell surface marker VE-cadherin, a protein which plays an important role in cell-cell interaction, was enhanced by ethanol, while (anti-)angiogenic molecule expression was not impacted.

Conclusion

Ethanol at moderate concentrations increases the angiogenic abilities of endothelial progenitor cells thus possibly contributing to vasoprotection.

Microparticles Carrying Peroxisome Proliferator-Activated Receptor Alpha Restore the Reduced Differentiation and Functionality of Bone Marrow-Derived Cells Induced by High-Fat Diet

Metabolic pathologies such as diabetes and obesity are associated with decreased level of circulating and bone marrow (BM)-derived endothelial progenitor cells (EPCs). It is known that activation of peroxisome proliferator-activated receptor alpha (PPARα) may stimulate cell differentiation. In addition, microparticles (MPs), small membrane vesicles produced by activated and apoptotic cells, are able to reprogram EPCs. Here, we evaluated the role of MPs carrying PPARα on both phenotype and function of progenitor cells from mice fed with a high-fat diet (HFD). HFD reduced circulating EPCs and, after 7 days of culture, BM-derived EPCs and monocytic progenitor cells from HFD-fed mice displayed impaired differentiation. At the same time, we show that MPs bearing PPARα, MPs^PPARα+/+ , increased the differentiation of EPCs and monocytic progenitors from HFD-fed mice, whereas MPs taken from PPARα knockout mice (MPs^PPARα-/- ) had no effect on the differentiation of all types of progenitor cells. Furthermore, MPs^PPARα+/+ increased the ability of progenitor cells to promote in vivo angiogenesis in mice fed with HFD. The in vitro and in vivo effects of MPs^PPARα+/+ were abolished in presence of MK886, a specific inhibitor of PPARα. Collectively, these data highlight the ability of MPs carrying PPARα to restore the failed differentiation and functionality of BM-derived cells induced by HFD. Stem Cells Translational Medicine 2018;7:135-145.