Pietro Mesirca

In Vitro Exposure of Human Lymphocytes to 900 MHz CW and GSM Modulated Radiofrequency: Studies of Proliferation, Apoptosis and Mitochondrial Membrane Potential

Abstract Capri, M., Scarcella, E., Fumelli, C., Bianchi, E., Salvioli, S., Mesirca, P., Agostini, C., Antolini, A., Schiavoni, A., Castellani, G., Bersani, F. and Franceschi, C. In Vitro Exposure of Human Lymphocytes to 900 MHz CW and GSM Modulated Radiofrequency: Studies of Proliferation, Apoptosis and Mitochondrial Membrane Potential. Radiat. Res. 162, 211–218 (2004). The aim of this study was to investigate the nonthermal effects of radiofrequency (RF) fields on human immune cells exposed to a Global System for Mobile Communication (GSM) signal generated by a commercial cellular phone and by a sinusoidal non-modulated signal. To assess whether mobile phone RF-field exposure affects human immune cell functions, peripheral blood mononuclear cells (PBMCs) from healthy donors were exposed in vitro to a 900 MHz GSM or continuous-wave (CW) RF field 1 h/day for 3 days in a transverse electromagnetic mode (TEM) cell system (70–76 mW/kg average specific absorption rate, SAR). The cells were cultured for 48 or 72 h, and the following end points were studied: (1) mitogen-induced proliferation; (2) cell cycle progression; (3) spontaneous and 2-deoxy-d-ribose (dRib)-induced apoptosis; (4) mitochondrial membrane potential modifications during spontaneous and dRib-induced-apoptosis. Data obtained from cells exposed to a GSM-modulated RF field showed a slight decrease in cell proliferation when PBMCs were stimulated with the lowest mitogen concentration and a slight increase in the number of cells with altered distribution of phosphatidylserine across the membrane. On the other hand, cell cycle phases, mitochondrial membrane potential and susceptibility to apoptosis were found to be unaffected by the RF field. When cells were exposed to a CW RF field, no significant modifications were observed in comparison with sham-exposed cells for all the end points investigated.

Turning on stem cell cardiogenesis with extremely low frequency magnetic fields

Modulation of stem cell differentiation is an important assignment for cellular engineering. Embryonic stem (ES) cells can differentiate into cardiomyocytes, but the efficiency is typically low. Here, we show that exposure of mouse ES cells to extremely low frequency magnetic fields triggered the expression of GATA‐4 and Nkx‐2.5, acting as cardiac lineage‐promoting genes in different animal species, including humans. Magnetic fields also enhanced prodynorphin gene expression, and the synthesis and secretion of dynorphin B, an endorphin playing a major role in cardiogenesis. These effects occurred at the transcriptional level and ultimately ensued into a remarkable increase in the yield of ES‐derived cardiomyocytes. These results demonstrate the potential use of magnetic fields for modifying the gene program of cardiac differentiation in ES cells without the aid of gene transfer technologies and may pave the way for novel approaches in tissue engineering and cell therapy.

1800 MHZ RADIOFREQUENCY (MOBILE PHONES, DIFFERENT GLOBAL SYSTEM FOR MOBILE COMMUNICATION MODULATIONS) DOES NOT AFFECT APOPTOSIS AND HEAT SHOCK PROTEIN 70 LEVEL IN PERIPHERAL BLOOD MONONUCLEAR CELLS FROM YOUNG AND OLD DONORS

Purpose: To study if prolonged in vitro exposure to 1800 MHz radiofrequency (RF) could exert an effect on human peripheral blood mononuclear cells (PBMC) from young and elderly donors by affecting apoptosis, mitochondrial membrane potential and heat shock protein (HSP) 70 levels. Materials and methods: Endpoints were analysed in the presence or absence of the apoptosis‐inducing agent 2‐deoxy‐D‐ribose. Three different signal modulations typical of the Global System for Mobile communication (GSM) system were applied. The modulations are widely used in mobile telephony (GSM Basic, discontinuous transmission [DTX] and Talk) at specific absorption rates of 1.4 and 2.0 W kg−1. Results: In all conditions and for all endpoints tested, there was no significant difference between RF‐ and sham‐exposed cells. Conclusion: 1800 MHz RF could not induce apoptosis by itself or affect the apoptotic phenomenon when induced by an apoptotic agent. Moreover, RF did not modify the mitochondrial functionality and the expression of HSP 70.

Effect of radiofrequency electromagnetic field exposure on in vitro models of neurodegenerative disease

In this work we tested viability, proliferation, and vulnerability of neural cells, after continuous radiofrequency (RF) electromagnetic fields exposure (global system for mobile telecommunications (GSM) modulated 900 MHz signal at a specific absorption rate (SAR) of 1 W/kg and maximum duration 144 h) generated by transverse electromagnetic cells. We used two cellular systems, SN56 cholinergic for example, SN56 cholinergic cell line and rat primary cortical neurons, and well-known neurotoxic challenges, such as glutamate, 25-35AA beta-amyloid, and hydrogen peroxide. Exposure to RF did not change viability/proliferation rate of the SN56 cholinergic cells or viability of cortical neurons. Co-exposure to RF exacerbated neurotoxic effect of hydrogen peroxide in SN56, but not in primary cortical neurons, whereas no cooperative effects of RF with glutamate and 25-35AA beta-amyloid were found. These data suggest that only under particular circumstances exposure to GSM modulated, 900 MHz signal act as a co-stressor for oxidative damage of neural cells.

Continuous exposure to 900 MHz GSM-modulated EMF alters morphological maturation of neural cells

The effects of radiofrequency electromagnetic field (RF-EMF) exposure on neuronal phenotype maturation have been studied in two different in vitro models: murine SN56 cholinergic cell line and rat primary cortical neurons. The samples were exposed at a dose of 1W/kg at 900 MHz GSM modulated. The phenotype analysis was carried out at 48 and 72 h (24 and 48 h of SN56 cell line differentiation) or at 24, 72, 120 h (2, 4 and 6 days in vitro for cortical neurons) of exposure, on live and immunolabeled neurons, and included the morphological study of neurite emission, outgrowth and branching. Moreover, cortical neurons were studied to detect alterations in the expression pattern of cytoskeleton regulating factors, e.g. beta-thymosin, and of early genes, e.g. c-Fos and c-Jun through real-time PCR on mRNA extracted after 24h exposure to EMF. We found that RF-EMF exposure reduced the number of neurites generated by both cell systems, and this alteration correlates to increased expression of beta-thymosin mRNA.

Evaluation of Genotoxic Effects in Human Fibroblasts after Intermittent Exposure to 50 Hz Electromagnetic Fields: A Confirmatory Study

Abstract Scarfí, M. R., Sannino, A., Perrotta, A., Sarti, M., Mesirca, P. and Bersani, F. Evaluation of Genotoxic Effects in Human Fibroblasts after Intermittent Exposure to 50 Hz Electromagnetic Fields: A Confirmatory Study. Radiat. Res. 164, 270–276 (2005). The aim of this investigation was to confirm the main results reported in recent studies on the induction of genotoxic effects in human fibroblasts exposed to 50 Hz intermittent (5 min field on/10 min field off) sinusoidal electromagnetic fields. For this purpose, the induction of DNA single-strand breaks was evaluated by applying the alkaline single-cell gel electrophoresis (SCGE)/comet assay. To extend the study and validate the results, in the same experimental conditions, the potential genotoxicity was also tested by exposing the cells to a 50 Hz powerline signal (50 Hz frequency plus its harmonics). The cytokinesis-block micronucleus assay was applied after 24 h intermittent exposure to both sinusoidal and powerline signals to obtain information on cell cycle kinetics. The experiments were carried out on human diploid fibroblasts (ES-1). For each experimental run, exposed and sham-exposed samples were set up; positive controls were also provided by treating cells with hydrogen peroxide or mitomycin C for the comet or micronucleus assay, respectively. No statistically significant difference was detected in exposed compared to sham-exposed samples in any of the experimental conditions tested (P > 0.05). In contrast, the positive controls showed a statistically significant increase in DNA damage in all cases, as expected. Accordingly, our findings do not confirm the results reported previously for either comet induction or an increase in micronucleus frequency.

Age‐Dependent Effects of in Vitro Radiofrequency Exposure (Mobile Phone) on CD95+ T Helper Human Lymphocytes

Abstract:  Recent studies on “nonthermal” effects of mobile phone radiofrequency (RF) suggest that RF can interact with cellular functions and molecular pathways. To study the possible RF effects on human lymphocyte activation, we analyzed CD25, CD95, CD28 molecules in unstimulated and stimulated CD4+ e CD8+ T cells in vitro. Peripheral blood mononuclear cells (PBMCs) from young and elderly donors were exposed or sham‐exposed to RF (1,800 MHz, Specific Absorption Rate 2 W/kg) with or without mitogenic stimulation. No significant changes in the percentage of these cell subsets were found between exposed and sham‐exposed lymphocytes in both young and elderly donors. Nevertheless, after RF exposure we observed a slight, but significant, downregulation of CD95 expression in stimulated CD4+ T lymphocytes from elderly, but not from young donors. This age‐related result is noteworthy given the importance of a such molecule in regulation of the immune response.

50 Hz sinusoidal magnetic fields do not affect human lymphocyte activation and proliferation in vitro

In the last 30 years, an increasing public concern about the possible harmful effects of electromagnetic fields generated by power lines and domestic appliances has pushed the scientific community to search for a correct and comprehensive answer to this problem. In this work the effects of exposure to 50 Hz sinusoidal magnetic fields, with a magnetic flux density of 0.05 mT and 2.5 mT (peak values), were studied on human peripheral blood mononuclear cells (PBMCs) collected from healthy young and elderly donors. Cell activation and proliferation were investigated by using flow cytometry techniques and 3H-TdR incorporation assays, respectively. The results obtained indicated that exposure to the fields altered neither DNA synthesis nor the capacity of lymphocytes to enter the activation phase and progress into the cell cycle. Thus, the conclusions are that two important functional phases of human lymphocytes, such as activation and proliferation, are not affected by exposures to 50 Hz magnetic fields similar to those found under power lines.

Weak Static and Extremely Low Frequency Magnetic Fields Affect In Vitro Pollen Germination

This study concerns the effects of a weak static magnetic field (MF) at 10 μT oriented downward, combined with a 16-Hz sinusoidal MF (10 μT), on in vitro pollen germination of kiwifruit (Actinidia deliciosa). Extremely low frequency magnetic field (ELF-MF) exposure was carried out by a signal generator unit connected to a copper wire solenoid, inside which samples where placed. Two different kinds of treatment were performed: direct and indirect. In the direct treatment, pollen samples were directly exposed during rehydration, germination, or both. In the indirect treatment, the pollen growth medium was prepared with water aliquots (at standard temperature of 20°C and pH = 6.74) that were exposed before use for 8 or 24 h. The main purpose of our research was to identify a biological marker (in vitro pollen germination in a stressing growth medium without Ca2+) susceptible to the effects of direct or indirect ELF-MF exposure. The working variable was the pollen germination rate, as detected blind after 3 h 30 min by an Axioplan microscope. A directionally consistent recovery of germination percentage was observed both for direct exposure (during germination and both rehydration and germination phases) and water-mediated exposure (with water exposed for 24 h and immediately used). Our results suggest that the ELF-MF treatment might partially remove the inhibitory effect caused by the lack of Ca2+ in the culture medium, inducing a release of internal Ca2+ stored in the secretory vesicles of pollen plasma membrane. Although preliminary, findings seem to indicate the in vitro pollen performance as adequate to study the effects of ELF-MFs on living matter.

Effects of exogenous electromagnetic fields on a simplified ion channel model.

In this paper, we calculate the effect of an exogenous perturbation (an electromagnetic field [EMF] oscillating in the range of microwave frequencies in the range of 1 GHz) on the flux of two ion species through a cylindrical ion channel, implementing a continuous model, the Poisson–Smoluchowski system of equations, to study the dynamics of charged particle density inside the channel. The method was validated through comparison with Brownian dynamics simulations, supposed to be more accurate but computationally more demanding, obtaining a very good agreement. No EMF effects were observed for low field intensities below the level for thermal effects, as the highly viscous regime and the simplicity of the channel do not exhibit resonance phenomena. For high intensities of the external field (>105 V/m), we observed slightly different behavior of ion concentration oscillations and ion currents as a function of EMF orientation with respect to the channel axis.