Five years later: the current status of the use of proteomics and transcriptomics in EMF research.

The World Health Organization's and Radiation and Nuclear Safety Authority's "Workshop on Application of Proteomics and Transcriptomics in Electromagnetic Fields Research" was held in Helsinki in the October/November 2005. As a consequence of this meeting, Proteomics journal published in 2006 a special issue "Application of Proteomics and Transcriptomics in EMF Research" (Vol. 6 No. 17; Guest Editor: D. Leszczynski). This Proteomics issue presented the status of research, of the effects of electromagnetic fields (EMF) using proteomics and transcriptomics methods, present in 2005. The current overview/opinion article presents the status of research in this area by reviewing all studies that were published by the end of 2010. The review work was a part of the European Cooperation in the Field of Scientific and Technical Research (COST) Action BM0704 that created a structure in which researchers in the field of EMF and health shared knowledge and information. The review was prepared by the members of the COST Action BM0704 task group on the high-throughput screening techniques and electromagnetic fields (TG-HTST-EMF).

Monolayers of porcine alveolar epithelial cells in primary culture as an in vitro model for drug absorption studies.

Filter-grown monolayers of porcine alveolar epithelial cells (pAEpC) in primary culture have been characterized as an in vitro model for pulmonary absorption screening of xenobiotics, including substrates of efflux systems. Experimental conditions and a protocol for transport experiments were optimized using transepithelial electrical resistances (TEER) and permeability of marker compounds as acceptance criteria. Since new drugs often feature poor water solubility, monolayer integrity in the presence of a solubilizer (dimethyl sulfoxide) was tested. Transport studies were carried out with budesonide and triamcinolone acetonide, i.e., two drugs commonly administered to the lungs. Furthermore, expression of P-glycoprotein (P-gp) was assessed by immunofluorescence microscopy and transport studies employing the substrates rhodamine 123 and digoxin. Hydrocortisone-supplemented (0.5 microg/ml) small airway basal medium as transport buffer and a maximal solubilizer concentration of 1.5% dimethyl sulfoxide were found to provide suitable conditions for drug transport studies across pAEpC, as reflected, e.g., by a minimum TEER of 600 Omega cm(2). Permeation of marker compounds was reproducible throughout several cell preparations and proved the model successful in distinguishing between low- and high-permeable drugs. P-gp expression was confirmed by immunocytochemistry, even though transport studies revealed no polarity in transepithelial marker transport. In conclusion, our results demonstrate that filter-grown monolayers of pAEpC can be used to study drug transport across alveolar epithelial barrier and thus, may represent a suitable in vitro model for pulmonary drug absorption and delivery.

Porcine alveolar epithelial cells in primary culture: morphological, bioelectrical and immunocytochemical characterization.

PURPOSE: The purpose of this study was to establish a primary culture of porcine lung epithelial cells as an alternative to the currently existing cell cultures from other species, such as e.g., rat or human. Primary porcine lung epithelial cells were isolated, cultivated and analyzed at distinct time points after isolation. MATERIALS AND METHODS: The main part of the work focused on the morphology of the cells and the detection of alveolar epithelial cell markers by using electron microscopy, immunofluorescence microscopy and immunoblotting. Regarding a later use for in vitro pulmonary drug absorption studies the barrier properties of the cell monolayer were evaluated by monitoring bioelectrical parameters and by marker transport. RESULTS: Epithelial cells isolated from porcine lung grew to confluent monolayers with typical intercellular junctions within a few days. Maximum transepithelial resistance of about 2,000 Omega cm2 was achieved and demonstrated the formation of a tight epithelial barrier. Permeability data of sodium fluorescein recommended a minimal transepithelial resistance of 600 Omega cm2 for transport studies. The cell population changed from a heterogeneous morphology and marker distribution (caveolin-1, pro-SP-C, surface sugars) towards a monolayer consisting of two cell types resembling type I and type II pneumocytes. CONCLUSIONS: The porcine alveolar epithelial primary cell culture holds promise for drug transport studies, because it shares major hallmarks of the mammalian alveolar epithelium and it is easily available and scaled up for drug screening.

Effects of Universal Mobile Telecommunications System (UMTS) electromagnetic fields on the blood-brain barrier in vitro.

The extensive use of mobile phone communication has raised public concerns about adverse health effects of radiofrequency (RF) electromagnetic fields (EMFs) in recent years. A central issue in this discussion is the question whether EMFs enhance the permeability of the blood-brain barrier (BBB). Here we report an investigation on the influence of a generic UMTS (Universal Mobile Telecommunications System) signal on barrier tightness, transport processes and the morphology of porcine brain microvascular endothelial cell cultures (PBEC) serving as an in vitro model of the BBB. An exposure device with integrated online monitoring system was developed for simultaneous exposure and measuring of transendothelial electrical resistance (TEER) to determine the tightness of the BBB. PBEC were exposed continuously for up to 84 h at an average electric-field strength of 3.4-34 V/m (maximum 1.8 W/kg) ensuring athermal conditions. We did not find any evidence of RF-field-induced disturbance of the function of the BBB. After and during exposure, the tightness of the BBB quantified by 14C-sucrose and serum albumin permeation as well as by TEER remained unchanged compared to sham-exposed cultures. Permeation of transporter substrates at the BBB as well as the localization and integrity of the tight-junction proteins occludin and ZO1 were not affected either.

Electromagnetic fields (GSM 1800) do not alter blood-brain barrier permeability to sucrose in models in vitro with high barrier tightness.

We previously reported that electromagnetic fields (EMFs) [GSM 1800 standard (Global System for Mobile Communications, 1800 MHz)] increased sucrose permeation across the blood-brain barrier (BBB) in vitro. The cell culture model used in our previous study was comprised of rat astrocytes in coculture with porcine brain microvascular endothelial cells (PBECs). In this study, after optimization of cell culture conditions, distinctly improved barrier tightness was observed, accompanied by a loss of susceptibility to EMF-related effects on BBB permeability. Cell cultures were exposed for 1-5 days at an average specific absorption rate (SAR) of 0.3 W/kg in the identical exposure system as described before. To quantify barrier tightness, sucrose permeation across exposed PBEC was measured and compared to values of sham exposed cells and to a control group. Additionally, observations in the BBB coculture system were complemented by similar experiments using two other in vitro models, composed of PBEC monocultures with or without serum. These three models display distinctly higher barrier tightness than the previously used system. In all three BBB models, sucrose permeation across the cell layers remained unaffected by exposure to a GSM 1800 field for up to 5 days. We thus could not confirm enhanced permeability of the BBB in vitro after EMF exposure as reported before since the in vitro barrier tightness in these experiments is now more like that of the in vivo situation.