Cytotoxicity of water-soluble fullerene in vascular endothelial cells

Abstract

Nanoscale materials are presently under development for diagnostic (nanomedicine) and electronic purposes. In contrast to the potential benefits of nanotechnology, the effects of nanomaterials on human health are poorly understood. Nanomaterials are known to translocate into the circulation and could thus directly affect vascular endothelial cells (ECs), causing vascular injury that might be responsible for the development of atherosclerosis. To explore the direct effects of nanomaterials on endothelial toxicity, human umbilical vein ECs were treated with 1-100 microg/ml hydroxyl fullerene [C60(OH)24; mean diameter, 7.1 +/- 2.4 nm] for 24 h. C60(OH)24 induced cytotoxic morphological changes such as cytosolic vacuole formation and decreased cell density in a dose-dependent manner. Lactate dehydrogenase assay revealed that a maximal dose of C60(OH)24 (100 microg/ml) induced cytotoxic injury. Proliferation assay also showed that a maximal dose of C60(OH)24 inhibited EC growth. C60(OH)24 did not seem to induce apoptosis but caused the accumulation of polyubiquitinated proteins and facilitated autophagic cell death. Formation of autophagosomes was confirmed on the basis of Western blot analysis using a specific marker, light chain 3 antibody, and electron microscopy. Chronic treatment with low-dose C60(OH)24 (10 microg/ml for 8 days) inhibited cell attachment and delayed EC growth. In the present study, we have examined, for the first time, the toxicity of water-soluble fullerenes to ECs. Although fullerenes changed morphology in a dose-dependent manner, only maximal doses of fullerenes caused cytotoxic injury and/or death and inhibited cell growth. EC death seemed to be caused by activation of ubiquitin-autophagy cell death pathways. Although exposure to nanomaterials appears to represent a risk for cardiovascular disorders, further in vivo validations are necessary.

Perturbation of physiological systems by nanoparticles

“…Exposure of HUVECs to water-soluble fullerene induced an accumulation of polyubiquitinated proteins and the release of lactate dehydrogenase, an indicator of cell lysis. 123 Iron oxide nanoparticles, 124 CdTe quantum dots (QDs), 90 and SWCNTs 125 all decreased HUVEC viability and disrupted the cell cytoskeleton, leading to apoptotic cell death in a dose-dependent manner. Using freshly isolated human platelets as a study model, both silver nanoparticles 101 and amorphous SiO 2 nanoparticles 102 have been shown to lead to platelet aggregation.…”

Nanocomposite and Nanostructured Carbon-based Films as Growth Substrates for Bone Cells

“…We considered this result rather surprising, because many studies have reported cytotoxic and even genotoxic effects of fullerenes (Xu et al, 2009;Johnson-Lyles et al, 2010; for a review, see Bacakova et al, 2008a). However, the cytotoxic action of fullerenes was usually associated with suspending fullerenes in the cell culture medium (Yamawaki et al, 2006;Gelderman et al, 2008) or UV-light irradiation (Prylutska et al, 2010), while our fullerene layers were resistant to be dissolved in a water environment, and the cells were cultured in the dark. In addition, the cytotoxic effects of fullerenes are based mainly on the reactivity of fullerenes, which may weaken with time due to the oxidation and polymerization of fullerenes in an air atmosphere, ethanol or cell culture medium, as revealed by Raman spectroscopy.…”

Autophagy as new emerging cellular effect of nanomaterials

“…As early as in 2006, Yamawaki and Iwai [36] has found that the treatment of human umbilical vein endothelial cells (HUVECs) with 100 μg/mL C 60 (OH) 24 for 24 h caused extensive internalization of fullerene and vacuolization. They observed aggregated fullerene in autophagosome via TEM.…”

“…On one hand, fullerene-induced autophagy can cause cell death or functional damage, leading to the development of certain diseases [36,40]. On the other hand, fullerenetriggered autophagy was found to play potential role in the treatment of diseases such as cancer and neurodegeneration.…”