The endothelium, comprising microvascular endothelial cells lining blood vessels, plays a crucial role in maintaining organ function by regulating tissue fluid volume and nutrient supply for homeostasis. Nanoparticles (NPs), with their diminutive size and unique properties, hold promise for medical and pharmacological applications. However, they can disrupt fundamental cellular processes and contribute to various pathologies, including neurodegenerative diseases. Understanding the toxicological impact of NPs on endothelial cells and their interaction dynamics is imperative. This study aimed to assess the effects of iron oxide nanoparticles (FeNPs) on the growth and inflammatory activation of microvascular dermal endothelial cells (HMEC-1) in healthy and activated endothelium models. Cell growth assay, western blot, and iron uptake assessment were utilized. HMEC-1 cells were exposed to FeNPs at 20, 50, 100, and 500 μg/mL concentrations, revealing no significant modulation of cell growth. To simulate pathological conditions, we induced endothelial activation through lipopolysaccharide (LPS) pretreatment, confirming activation through increased NF-κβ expression (p=0.001) by western blot. Pretreatment with LPS did not alter the impact of FeNPs on HMEC-1 growth. Iron uptake measurements exhibited dependence on cell number (p=0.01) and concentration (p=0.01). Furthermore, while LPS pretreatment increased ICAM-1 expression (p=0.001), FeNPs did not affect ICAM protein levels of either control or pretreated cells (p=NS). These findings shed light on the nuanced interactions between endothelial cells and FeNPs, which is crucial for understanding their toxicity and inflammatory potential.

Conflicts of interest:
The authors declare that they have no conflict of interest in the publication of this article. The authors have no conflicts of interest to report in this work. Abstract was not submitted elsewhere and was first published here.

Funding:
The research was partly funded by the Special Research Account of the University of Crete (ELKE) KA:10985 to DN.