Cytotoxicity In Human Endothelial Cells Research Articles

Genistein Prevents Apoptosis and Oxidative Stress Induced by Methylglyoxal in Endothelial Cells.

Glycolytic overload promotes accumulation of the highly reactive dicarbonyl compounds, resulting in harmful conditions called dicarbonyl stress. Methylglyoxal (MG) is a highly reactive dicarbonyl species and its accumulation plays a crucial pathophysiological role in diabetes and its vascular complications. MG cytotoxicity is mediated by reactive oxygen species (ROS) generation, a key event underlying the intracellular signaling pathways leading to inflammation and apoptosis. The identification of compounds able to inhibit ROS signaling pathways and counteract the MG-induced toxicity is a crucial step for developing new therapeutic strategies in the treatment of diabetic vascular complications. In this study, the effect of genistein, a natural soybean isoflavone, has been evaluated on MG-induced cytotoxicity in human endothelial cells. Our results show that genistein is able to counteract the MG-induced apoptosis by restraining ROS production, thus inhibiting the MAPK signaling pathways and caspase-3 activation. These findings identify a beneficial role for genistein, providing new insights for its potential clinical applications in preserving endothelial function in diabetic vascular complications.

Human Lactoferrin Synergizes with Etoposide to Inhibit Lung Adenocarcinoma Cell Growth While Attenuating Etoposide-Mediated Cytotoxicity of Human Endothelial Cells.

Lung cancer continues to be the deadliest cancer worldwide. A new strategy of combining chemotherapeutics with naturally occurring anticancer compounds, such as lactoferrin, might improve the efficacy and toxicity of current chemotherapy. The aim of this study was to evaluate the effect of recombinant human lactoferrin (rhLf) in combination with etoposide on anticancer activity in human lung adenocarcinoma cells. In addition, we examined the impact of rhLf on etoposide-induced cytotoxicity of human endothelial cells. We found that treatment of A549 cells with a combination of etoposide and rhLf resulted in significantly greater inhibition of cancer cell growth as compared to etoposide alone. The combination repressed cancer cell growth by cell cycle arrest in the G2/M phase and induction of apoptosis. In contrast to cancer cells, rhLf did not affect endothelial cell viability. Importantly, rhLf significantly diminished the etoposide-induced cytotoxicity of endothelial cells. Analysis of the type of drug interaction based on combination index value showed that rhLf synergized with etoposide to induce anticancer activity. The calculated dose reduction index indicated that the combination treatment reduced a 10-fold of etoposide dose to achieve the same anticancer effect. Our data demonstrate that rhLf enhanced the anticancer activity of etoposide and diminished etoposide-induced cytotoxic effect in endothelial cells.

The offset effect of a hyaluronic acid coating to cationic carriers containing siRNA: Alleviated cytotoxicity and retained gene silencing in vitro

small interfering RNA (siRNA) has been suggested as a potential therapeutic molecule, whereby potent gene silencing is precisely controlled by RNAi machinery. Cationic liposome-protamine-DNA (LPD) has been traditionally used as the carrier of functional nucleic acids. The cytotoxicity derived from the cationic moiety has raised a concern to safely deliver nucleic acids, such as siRNA, to the target site. In the present study, LPD was coated with the natural anionic polymer, hyaluronic acid (HA), termed LPDH. The cytotoxicity and safety of LPDH was assessed in vitro. LPD induced hemolysis of murine red blood cells and cytotoxicity in human endothelial cells, while LPDH remarkably reduced the hemolysis and cytotoxicity when compared to LPD at the same concentration of siRNA. Fluorescently-labeled LPD showed increased cellular uptake when compared to LPDH. In contrast, LPD and LPDH showed similar effects on gene silencing for the luciferase gene on the luciferase-expressing B16F0 cancer cell line. PEGylated LPD obstructed this gene silencing effect. These results indicate that LPDH can reduce the cytotoxicity associated with LPD with a comparable gene silencing response, suggesting that the coating of hyaluronic acid with cationic carriers is effective strategy to deliver siRNA with less cytotoxicity.

Salidroside Inhibits Endogenous Hydrogen Peroxide Induced Cytotoxicity of Endothelial Cells

To explore the protective effects of salidroside against endogenous hydrogen peroxide (H2O2) -induced cytotoxicity in human endothelial cells (EVC-304). EVC-304 cells were incubated in the presence or absence of low steady states of H2O2 (34μM) generated by glucose oxidase (GOX) with or without salidroside. MTT assays were performed, together with flow cytometric analysis using propidium (PI) label. The results indicated that salidroside could attenuate H2O2 induced cytotoxicity in EVC-304 cells in a dose-dependent pattern. Furthermore, flow cytometric analysis revealed that salidroside could also inhibited the G2/M arrest induced by endogenous hydrogen. The present study demonstrates that salidroside could inhibit endogenous hydrogen peroxide induced cytotoxicity of endothelial cells .

Oxidative Stress Induced by Pure and Iron-Doped Amorphous Silica Nanoparticles in Subtoxic Conditions

Amorphous silica nanoparticles (SiO₂-NPs) have found broad applications in industry and are currently intensively studied for potential uses in medical and biomedical fields. Several studies have reported cytotoxic and inflammatory responses induced by SiO₂-NPs in different cell types. The present study was designed to examine the association of oxidative stress markers with SiO₂-NP induced cytotoxicity in human endothelial cells. We used pure monodisperse amorphous silica nanoparticles of two sizes (16 and 60 nm; S16 and S60) and a positive control, iron-doped nanosilica (16 nm; SFe), to study the generation of hydroxyl radicals (HO·) in cellular-free conditions and oxidative stress in cellular systems. We investigated whether SiO₂-NPs could influence intracellular reduced glutathione (GSH) and oxidized glutathione (GSSG) levels, increase lipid peroxidation (malondialdehyde (MDA) and 4-hydroxyalkenal (HAE) concentrations), and up-regulate heme oxygenase-1 (HO-1) mRNA expression in the studied cells. None of the particles, except SFe, produced ROS in cell-free systems. We found significant modifications for all parameters in cells treated with SFe nanoparticles. At cytotoxic doses of S16 (40-50 μg/mL), we detected weak alterations of intracellular glutathione (4 h) and a marked induction of HO-1 mRNA (6 h). Cytotoxic doses of S60 elicited similar responses. Preincubation of cells being exposed to SiO₂-NPs with an antioxidant (5 mM N-acetylcysteine, NAC) significantly reduced the cytotoxic activity of S16 and SFe (when exposed up to 25 and 50 μg/mL, respectively) but did not protect cells treated with S60. Preincubation with NAC significantly reduced HO-1 mRNA expression in cells treated with SFe but did not have any effect on HO-1 mRNA level in cell exposed to S16 and S60. Our study demonstrates that the chemical composition of the silica nanoparticles is a dominant factor in inducing oxidative stress.

Oxidative stress and mitochondria damage contribute to silica nanoparticle-induced cytotoxicity in human endothelial cells

Oxidative stress and mitochondria damage contribute to silica nanoparticle-induced cytotoxicity in human endothelial cells

HIV protease inhibitor ritonavir induces cytotoxicity of human endothelial cells.

Although HIV protease inhibitors have been successfully used against HIV infection, many metabolic side effects and premature cardiovascular diseases are often associated with this therapy. The mechanisms of these complications are not clear. In this study, we investigated the effect of the HIV protease inhibitor ritonavir on human endothelial cell cultures. By using nonradioactive cell proliferation and cytotoxicity assays, human endothelial cells treated with ritonavir showed a significant decrease in cell viability and an increase in cytotoxicity in a time- and dose-dependent fashion. Mitochondrial DNA was also substantially damaged with ritonavir treatment by long polymerase chain reaction analysis. In contrast, ritonavir had a very limited effect on endothelial apoptosis, as assessed by analyses of DNA fragmentation and cellular caspase-3 activity. These data demonstrate, for the first time, that the HIV protease inhibitor ritonavir at concentrations near clinical plasma levels is able to directly cause endothelial mitochondrial DNA damage and cell death mainly through necrosis pathways but not through apoptosis. This study suggests that HIV protease inhibitor-mediated endothelial injury may contribute to its cardiovascular complications.

Endothelial cell cytotoxicity in inflammatory vascular diseases--the possible role of oxidised lipoproteins.

One of the proposed mechanisms of vascular damage in connective tissue disease is the direct action of a cytotoxic serum factor inducing endothelial cell damage. The nature of this serum factor is unclear, but has been suggested to be a lipoprotein. Sera from patients with (1) systemic necrotising arteritis (polyarteritis nodosa, Wegener's granulomatosis, and necrotising arteritis associated with rheumatoid synovitis), (2) systemic or joint restricted rheumatoid disease, and (3) large vessel/giant cell arteritis have been examined for cytotoxicity to human cultured endothelial cells and azide-resistant ferroxidase-like activity (indicative of the oxidised lipoprotein content). Stored sera from patients with necrotising arteritis showed a significantly enhanced tendency to develop oxidised lipoprotein, which correlated closely with human endothelial cell cytotoxicity. Fresh sera also contained this factor, but to a lesser extent. It is argued that the cytotoxic factor detected in previous clinical studies is in part an in-vitro artefact, although its accelerated development in certain patient groups might suggest an excess of pro-oxidants that have developed in vivo.

In vitro cytotoxicity of human endothelial cells in polymyalgia rheumatica and giant cell arteritis.

We studied sera from 20 patients with polymyalgia rheumatica (PMR)/giant cell arteritis (GCA), 15 patients with systemic lupus erythematosus (SLE), 15 patients with the CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangietasia) and 33 age and sex matched controls for cytotoxicity against human endothelial cells using a 51Cr release assay. We observed increased levels of endothelial cytotoxic activity in the PMR/GCA sera compared with controls (P less than 0.001). This cytotoxicity was predominantly found in the GCA group, where 7 out of 10 patients (70%) demonstrated significant cytotoxicity. Sequential studies showed that the cytotoxic activity returned to normal when the disease was under control. Although 7 SLE and 3 CREST sera had significant cytotoxic activity, as a group they did not differ from controls (P less than 0.05). Pre-incubation with soybean trypsin inhibitor suppressed the cytotoxic activity in the positive sera suggesting the cytotoxicity is mediated via a protease mechanism. Our results demonstrate the presence of a cytotoxic factor in the serum of patients with PMR/GCA which may play an important role in the pathogenesis of the vascular lesions observed in these disorders.