https://doi.org/10.1007/s00392-025-02625-4
1Universitätsklinikum Giessen und Marburg GmbH Klinik für Kardiologie, Angiologie und internistische Intensivmedizin Marburg, Deutschland; 2Universitätsklinikum Giessen und Marburg GmbH Klinik für Innere Medizin - Schwerpunkt Kardiologie Marburg, Deutschland
Background and Aims: Nano-/microplastics cause inflammation in various cells and tissues, also known for particles from other materials, e.g., metal particles. In this comparative study, we investigate the influence of particle material, size and concentration on NF-κB activation, a key regulator of inflammation, in monocytes.
Methods and Results: We used the following nano- (~100 nm) and microparticles (~1 µm): plastic polymers (polystyrene = PS, polymethyl methacrylate = PMMA, polyethylene = PE, polypropylene = PP), metals (aluminum, cobalt, iron), biodegradable material (poly-D,L-lactic acid = PLA) and glass (silica) at low (106/ml) and high (108/ml) concentration. NF-κB activation was analyzed using THP-1 cells expressing an NF-κB-inducible reporter (secreted embryonic alkaline phosphatase, SEAP). For this purpose, the cells were stimulated with the nano- and microparticles for 20 hours and the supernatant was subsequently measured photometrically at 620 nm.
The activation of the NF-κB signaling pathway by particles in THP-1 cells was initially exemplarily tested using PS particles and found to induce NF-κB-dependent gene expression (qPCR) as well as the induction of the SEAP reporter in THP-1 cells, which was prevented by the endocytosis inhibitor chlorpromazine. Compared to the positive control lipopolysaccharide (LPS, 10-15-fold), the inflammatory response was, as expected, considerably diminished (maximal 2-fold).
Except for aluminium, we subsequently detected a significant activation of NF-κB with microparticles at high concentrations for all materials used (PE +130% > PP +110% > PS +35% > cobalt +25% > PMMA +17% >PLA +13% >silica +8%), but practically none at low concentrations or with nanoparticles.
Conclusions: Our results show that the size and concentration of particles have a decisive influence on cellular inflammatory activation and the material influences the intensity of the effects. However, the potential dangers microplastic particles pose are the highest due to their ubiquitous prevalence in our environment.