Endothelial and Cardiac Cells

The cardiovascular system is operated by the heart and blood vessels, or vasculature. The heart is a muscular organ that provides the force to pump the blood throughout the body in a network of blood vessels (arteries, veins, and capillaries). These blood vessels are lined by a layer of endothelial cells, which perform a multitude of functions that help maintain vasculature homeostasis. Endothelial cells produce vasodilators like nitric oxide to signal vessels to dilate, or vasoconstrictors like thromboxane, which have the opposite effect. They also play a role in wound repair. Endothelial cells also play a role in development of cardiovascular disease, and endothelial cell dysfunction is associated with a number of conditions, including atherosclerosis and inflammation.

Lifeline® provides normal human endothelial cells and cardiac cells, along with fully optimized media for culturing these products.

Our catalog includes large vessel endothelial cells isolated from:

Microvascular endothelial cells are available from:

Our catalog of cardiac cells includes:

Recent Studies Using Lifeline® HUVECs in Nanoparticle and Hypoxia Research

Nanoparticles are tiny particles, defined as 1–100 nm in size. Because of their small size, they are currently being developed as drug carriers for disease therapy. The ability of nanoparticles to efficiently deliver a drug to an intended target depends on their ability to bind to a target molecule on the cell surface. To validate this, microscopy-based imaging techniques are used to visualize and count the number of nanoparticles bound to live cells in culture. However, nanoparticles are difficult to quantify, as they can be approximately the same size (or smaller) than a pixel generated by a microscope. Therefore, quantifying nanoparticle binding to cells with traditional fluorescence microscopy has been a limiting factor in nanoparticle research.

Given these challenges, Ranganathan and colleagues set out to test a newly developed method for imaging nanoparticles. Their new imaging calibration technique used radioisotope counting and fluorescence microscopy to quantify binding of antibody-conjugated polystyrene (PS) beads and rhodamine-dextran lysozyme nanogels (NGs) to cell surface molecules on the surface of Lifeline® human umbilical vein endothelial cells (HUVECs). PS beads were 240–270 nm in diameter (larger than an individual pixel), while NGs were approximately 140 nm in diameter (small than an individual pixel). The authors tested the binding of PS beads and NGs to HUVECs under shear flow, which is performed in vitro using a peristaltic pump to mimic the flow of blood that endothelial cells experience in the vasculature. They also tested whether activating HUVECs with tumor necrosis factor-alpha (TNF-a) affected binding compared with that in quiescent cells.

The researchers first demonstrated that in TNF-a-activated HUVEC cells, both PG beads and NGs had greatest binding in higher shear flow conditions (0.5 Pa). PS beads were maximally bound to cells during the first 45 minutes and was maintained until 3 hours, while the maximal binding of NGs occurred after 4 hours. The binding of PS beads did not depend on the concentration added. Next, the authors illustrated that NGs do not differentially bind quiescent or activated cells under high shear flow, but did have increased binding to quiescent cells in low shear stress, particularly after 4 hours. Finally, using NGs conjugated to a non-specific antibody as a control, the authors showed that antibody-specific NG binding to quiescent cells under high shear flow conditions increased over time.

Together, the results of this study present a novel imaging-based method for quantification of nanoparticle binding to live cells that is not limited by pixel size, allowing more quantitative assessment of nanoparticle binding.

Hypoxia occurs during periods of low oxygen. Hypoxia can stimulate a number of adverse effects and can have a significant impact on endothelial cell dysfunction. Previous studies have suggested that extract from Rhodiola creulata, a medicinal plant, might have beneficial effects on endothelial cell dysfunction induced by hypoxia. In a 2018 study, Chang et al. evaluated the mechanism behind the effects of Rhodiola creulata extract (RCE) on endothelial cells using Lifeline® HUVECs as a model system.

The authors first used high performance liquid chromatography to demonstrate that RCE is composed of 2.43% salidroside (a glucoside) and 1.1% tyrosol (a natural antioxidant). Next, using Lifeline® HUVECs, they found that RCE treatment reversed the negative effects of hypoxia on cell viability and nitric oxide production. Similarly, RCE treatment also reduced levels of hypoxia-induced reactive oxygen species and malondialdehyde, two markers of oxidative stress. RCE treatment increased phosphorylation of AMP-activated kinase (AMPK; an energy-regulated kinase), eNOS (endothelial nitric oxide synthase), and AKT (a kinase that regulates cell survival), suggesting that RCE activates these signaling pathways in hypoxic conditions.

Importantly, treatment with an AMPK inhibitor reduced these effects, suggesting that AMPK signaling is partially responsible for the effects of RCE under hypoxia. Finally, the authors demonstrated that hypoxia induces apoptosis, and this was abrogated by RCE treatment. Treatment with RCE and an ERK inhibitor illustrated that the effects of RCE on apoptosis are mediated by the ERK signaling pathway (a pro-survival and cell proliferation pathway).

Together, the results of this study suggest that RCE inhibits oxidative stress and apoptosis associated with hypoxia through AMPK and ERK signaling.

How do you use Lifeline® cells in your research? Let us know and your study could be featured here on the blog!