Author(s):
Chow S-C*, Zhang Y, Ng RWM, Hui S-YR, Solov’yov IA, Lui W-Y.
* School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
China
Published in:
Front Public Health 2024; 12: 1425023
Published: 09.08.2024
on EMF:data since 11.11.2024
Further publications: Studie gefördert durch:

Volkswagen Foundation (Lichtenberg professorship awarded to IAS), the Deutsche Forschungsgemeinschaft (SFB 1372 Magnetoreception and Navigation in Vertebrates, no. 395940726 to IAS; TRR386/1 – 2023 HYP*MOL, no 514664767 to IAS), the Ministry for Science and Culture of Lower Saxony Simulations Meet Experiments on the Nanoscale: Opening up the Quantum World to Artificial Intelligence (SMART) and Dynamik auf der Nanoskala: Von kohärenten Elementarprozessen zur Funktionalität (DyNano). IAS thanks the Federal Office for Radiation Protection for financial support (no. 2022-I-037, 3621EMF203). This work was supported by Seed Funding for Strategic Interdisciplinary Research Scheme (The University of Hong Kong).

Medical/biological studies
Go to EMF:data assessment

External RF-EMF alters cell number and ROS balance possibly via the regulation of NADPH metabolism and apoptosis.

Original Abstract

The influence of weak radio-frequency electromagnetic field (RF-EMF) on living organisms raises new concern because of the Industrial, Scientific, and Medical (ISM) frequency band at 6.78 MHz being promoted by the AirFuel Alliance for mid-range wireless power transfer (WPT) applications and product development. Human exposure to the RF-EMF radiation is unavoidable. In this study, we employed in vitro cell culture and molecular biology approach coupled with integrated transcriptomic and proteomic analyses to uncover the effects of RF-EMF on cells at molecular and cellular levels. Our study has demonstrated that weak RF-EMF is sufficient to exert non-thermal effects on human umbilical vein endothelial cells (HUVEC). Exposure of weak RF-EMF promotes cell proliferation, inhibits apoptosis and deregulates ROS balance. Alteration of several signaling pathways and key enzymes involved in NADPH metabolism, cell proliferation and ferroptosis were identified. Our current study provide solid evidence for the first time that the present safety standards that solely considered the thermal effect of RF-EMF on cell tissue are inadequate, prompt response and modification of existing Guidelines, Standards and
Regulation are warranted.

Keywords

RF-EMF radiation | mid-range wireless power transfer | cellular responses | metabolism | reactive oxygen species

Exposure:

6,78 MHz
Magnetic fields
10 µT; Zwischenfrequenz; drahtlose Energieübertragung
Exposed system:
Endothelzellen menschlicher Nabelschnurvenen (HUVEC)

Conclusion of study (according to author)

[...] Unsere aktuelle Studie liefert erstmals stichhaltige Beweise dafür, dass die derzeitigen Sicherheitsstandards, die ausschließlich die thermische Wirkung von RF-EMF auf Zellgewebe berücksichtigen, unzureichend sind und eine sofortige Reaktion und Änderung der bestehenden Leitlinien, Standards und Verordnungen gerechtfertigt ist (Auszug aus dem Abstract, übersetzt mit DeepL).

EMF:data assessment

Summary

The popularity of Qi-standard-certified wireless chargers in consumer electronics and manufacturing industries has drawn significant attention. The AirFuel Alliance, established by a group of companies, aims to expand the use of wireless power transfer (WPT) technology for mid-range applications. The ISM frequency band (industrial, scientific, and medical) could operate at 6.78 MHz and be utilized for mid-range transmission. As current safety regulations only consider the thermal effects of radiofrequency (RF) on tissues, potential non-thermal biological effects remain largely unexplored. In the interest of public health, it is imperative to investigate the biological impacts of RF in this context prior to the implementation of WPT technologies. A 2016 study demonstrated that weak RF fields (10 µT at 7 MHz) could influence cell growth and reactive oxygen species (ROS). This underscores the necessity to explore the molecular mechanisms by which weak RF fields in mid-range WPT can affect cellular processes. The present study investigates the effects of 6.78 MHz RF at 10 µT on human umbilical vein endothelial cells (HUVEC) in vitro using RNA sequencing and proteomic analyses.

Source: ElektrosmogReport - Issue 4/2024

Study design and methods

HUVECs were exposed to the described RF field (10 µT at 6.78 MHz) for 72 hours, with sham-exposed cells serving as controls. Researchers assessed cell number, apoptosis, ROS levels, and altered gene expression at the RNA and protein levels using transcriptomic and proteomic approaches. For selected candidates with altered gene expression, omics data were validated using quantitative PCR. Based on omics data, a KEGG (Kyoto Encyclopedia of Genes and Genome) pathway enrichment analysis was conducted. The KEGG analysis statistically determines whether specific pathway components are overrepresented in comparison to a normal expression profile.

Results

RF exposure resulted in a significant increase in cell numbers and a significant reduction in apoptotic cells. ROS homeostasis was disrupted, with a significant decrease in superoxide anion levels. A total of 101 differentially expressed genes (transcriptomics) and 136 differentially expressed proteins (proteomics) were identified. In terms of molecular function, these differentially expressed genes (DEGs) and proteins (DEPs) were primarily enriched in oxidoreductase activities, aldo-keto reductase (NADP) activities, and malic enzyme activities. KEGG analysis revealed significant enrichment of several canonical pathways, including energy metabolism (pyruvate metabolism and pentose phosphate pathway), focal adhesion pathways, folate biosynthesis, and PI3K-Akt signaling pathways at both transcriptional and translational levels. Key genes related to NADPH/NADH homeostasis, including ME1 (malic enzyme 1) and NNT (nicotinamide nucleotide transhydrogenase), were significantly altered in expression following RF exposure. Components of the folate biosynthesis pathway, including AKR1B, AKR1C, and SPR, were significantly upregulated. The folate biosynthesis pathway is not only a presumed NADPH production pathway but also serves as a key component for maintaining the BH4/BH2 (tetrahydrobiopterin/dihydrobiopterin) balance. A higher BH4/BH2 ratio is known to favor ROS detoxification, reducing oxidative stress and promoting cell proliferation.

Conclusions

The study’s results indicate that RF (10 µT at 6.78 MHz) modulates various pathways and enzymes that regulate NADPH levels, ROS homeostasis, and apoptosis, both directly and indirectly. Uncontrolled growth and apoptosis evasion are hallmarks of all cancer cells, regardless of origin or type. Numerous studies suggest that regenerating and maintaining high NADPH levels plays a vital role in tumor formation. The two enzymes, ME1 and NNT, directly involved in the citric acid cycle and the electron transport chain, were significantly elevated following RF exposure. Both enzymes are dysregulated in various cancers and are associated with disease progression and prognosis. Aldo-keto reductases (AKRs) and sepiapterin reductase (SPR) are critical enzymes in BH4 biosynthesis. Numerous studies have shown that AKRs and BH4 synthesis possess antioxidant properties, protecting cells from ferroptosis. Another notable instance of tumorigenic factor upregulation is the alteration of the PI3K-Akt signaling pathway. Effectors such as PKN, CCND1, and VEGF, associated with tumor growth and vascularization, were significantly increased. According to the authors, the upregulation of various pro-tumorigenic factors indeed suggests that applying RF in the mid-range (e.g., for wireless power transfer) poses a health risk. The study provides robust evidence that current safety standards, based solely on the thermal effects of radiofrequency electromagnetic fields, are inadequate. Immediate action, including changes to existing guidelines, is warranted. (RH)