Effects of gradient high-field static magnetic fields on diabetic mice

Redox imbalance drives magnetic property and function changes in mice

The magnetic properties of substances directly determine their response to an externally applied magnetic field, which are closely associated with magnetoreception, magnetic resonance imaging (MRI), and magnetic bioeffects. However, people's understanding of the magnetic properties of living organisms remains limited. In this study, we utilized NRF2 (nuclear factor erythroid 2-related factor 2) deficient mice to investigate the contribution of redox (oxidation-reduction) homeostasis, in which the key process is the transfer of electron, a direct target of magnetic field and origin of paramagnetism. Our results show that the NRF2-/- mice exhibit significantly altered systemic redox state, accompanied by increased magnetic susceptibility, particularly in the liver and spleen. Further analyses reveal that the levels of paramagnetic reactive oxygen species (ROS) in these tissues are markedly elevated compared to wild-type mice. Moreover, the concentrations of Fe2+ and Fe3+ are significantly elevated in NRF2-/- mice, which are directly correlated with the increased magnetic susceptibility. The disrupted redox balance in NRF2-/- mice not only exacerbates oxidative stress and iron deposition, but also induces impairment to the liver and spleen. The findings highlight the combined effects of ROS and iron metabolism in driving magnetic susceptibility changes, providing valuable theoretical insights for further research into magnetic bioeffects and organ-specific sensitivity to magnetic fields.

Effects of Static and Low-Frequency Magnetic Fields on Gene Expression

Substantial research over the past two decades has established that magnetic fields affect fundamental cellular processes, including gene expression. However, since biological cells and subcellular components exhibit diamagnetic behavior and are therefore subjected to very small magnetic forces that cannot directly compete with the viscoelastic and bioelectric intracellular forces responsible for cellular machinery functions, it becomes challenging to understand cell-magnetic field interactions and to reveal the mechanisms through which these interactions differentially influence gene expression in cells. The limited understanding of the molecular mechanisms underlying biomagnetic effects has hindered progress in developing effective therapeutic applications of magnetic fields. This review examines the expanding body of literature on genetic events during static and low-frequency magnetic field exposure, focusing particularly on how changes in gene expression interact with cellular machinery. To address this, we conducted a systematic review utilizing extensive search strategies across multiple databases. We explore the intracellular mechanisms through which transcription functions may be modified by a magnetic field in contexts where other cellular signaling pathways are also activated by the field. This review summarizes key findings in the field, outlines the connections between magnetic fields and gene expression changes, identifies critical gaps in current knowledge, and proposes directions for future research. LEVEL OF EVIDENCE: NA TECHNICAL EFFICACY: Stage 4.

The Effects of Moderate to High Static Magnetic Fields on Pancreatic Damage

BACKGROUND

Pancreatic damage is a common digestive system disease with no specific drugs. Static magnetic field (SMF), the key component of magnetic resonance imaging (MRI), has demonstrated prominent effects in various disease models.

PURPOSE

To study the effects of 0.1-9.4 T SMFs on pancreatic injury induced by alcohol, and acute pancreatitis (AP) induced by L-arginine (L-Arg).

STUDY TYPE

Prospective, animal model.

ANIMAL MODEL

Twelve healthy C57BL/6J male mice, 30 AP model male mice, and 30 alcohol-associated liver disease (AALD) model male mice.

FIELD STRENGTH/SEQUENCE

1.5-9.4 T SMFs for 12 hours and 0.1 T SMF for 72 hours. No imaging sequence was used.

ASSESSMENT

Histological analysis on AALD mice pancreas was conducted. For L-Arg-induced AP mice, their body weight, food/water consumption, open field behavior, blood analysis, as well as histological analysis, inflammatory, oxidative stress of the pancreas were measured. In vitro cellular experiments were also conducted.

STATISTICAL TESTS

Data are presented as means ± SD and analyzed using the two-tailed Student's t-test or one-way analysis of variance (ANOVA) test. P values <0.05 were considered statistically significant.

RESULTS

1.5-7 T SMFs significantly reduced alcohol-induced pancreatic damage, increasing the structurally intact acinar area from 51.5% to 78.3%, whereas the effect of 9.4 T SMF is not obvious. 0.1 T SMF can reduce the AP mice lethality, increase the structurally intact acinar area from 31.0% to 59.7%, associated with the reduced pancreatic inflammatory responses (78.1% reduction of F4/80 and 80.0% reduction of MPO), 20.0% decreased oxidative stress and 53.2% reduced pancreatic cell apoptosis.

DATA CONCLUSION

High-field MRI may be safe for pancreatic-related diseases at the animal level. SMFs have a future potential to be developed as non-invasive and highly penetrating physical modalities for the treatment of pancreatic injury including AP.

PLAIN LANGUAGE SUMMARY

This study aims to evaluate the safety and potential therapeutic effects of moderate- to high-intensity static magnetic fields (SMFs) on mice with pancreatic injury. Their findings revealed that SMFs between 1.5 and 7 Tesla (T) helped reduce alcohol-induced pancreatic damage, while a stronger 9.4 T showed no effect. Interestingly, for mice with L-arginine-induced acute pancreatitis, a weaker 0.1 T significantly increased the area of healthy acinar cells from 31.0% to 59.7%. These results not only suggest that MRI-related SMFs are safe for pancreatic diseases in animals, but also unravel the potential of SMFs as a future treatment option for pancreatic disorders.

EVIDENCE LEVEL

N/A TECHNICAL EFFICACY: Stage 1.

Tricetin attenuates atherosclerosis by suppressing macrophage ferroptosis via activation of the NRF2 pathway

Tricetin (TRI) has been reported to have anti-inflammatory and antioxidant effects; however, its therapeutic potential and molecular mechanisms in atherosclerosis remain unclear. In this study, we aimed to investigate the effects of TRI on atherosclerosis. Our findings revealed that TRI inhibits macrophage ferroptosis by activating the NRF2 pathway. In vivo, ApoE-/- mice fed a high-fat diet and injected with TRI showed improved atherosclerosis progression through reduced oxidative stress and suppression of macrophage ferroptosis. In vitro experiments demonstrated that TRI administration increases GPX4 and xCT levels, attenuates oxidative stress, improves mitochondrial function, and inhibits lipid peroxidation, thereby suppressing ox-LDL-induced macrophage ferroptosis. Furthermore, TRI enhanced the nuclear translocation of NRF2. Notably, the protective effects of TRI on antioxidant capacity and ferroptosis were reversed in macrophages treated with ML385 (a specific NRF2 inhibitor). NRF2 knockdown in ApoE-/- mice using AAV-sh-NRF2 significantly reversed TRI-mediated inhibition of atherosclerosis progression and exacerbated macrophage ferroptosis in the plaque. Conclusively, this study identifies TRI as a potential therapeutic agent for atherosclerosis by inhibiting macrophage ferroptosis and oxidative stress through activation of the NRF2 pathway, offering a novel strategy to combat disease progression.

Effects of 16.8-22.0 T high static magnetic fields on the development of zebrafish in early fertilization

OBJECTIVES

Despite some existing studies on the safety of high static magnetic fields (SMFs), the effects of ultra-high SMFs above 20.0 T for embryonic development in early pregnancy are absent. The objective of this study is to evaluate the influence of 16.8-22.0 T SMF on the development of zebrafish embryos, which will provide important information for the future application of ultra-high field magnetic resonance imaging (MRI).

METHODS

Two-hour exposure to homogenous (0 T/m) 22.0 T SMF, or 16.8 T SMFs with 123.25 T/m spatial gradient of opposite magnetic force directions was examined in the embryonic development of 200 zebrafish. Their body length, heart rate, spontaneous tail-wagging movement, hatching and survival rate, photomotor response, and visual motor response (VMR) were analyzed.

RESULTS

Our results show that these ultra-high SMFs did not significantly affect the general development of zebrafish embryos, such as the body length or spontaneous tail-wagging movement. However, the hatching rate was reduced by the gradient SMFs (p < 0.05), but not the homogenous 22.0 T SMF. Moreover, although the zebrafish larva activities were differentially affected by these ultra-high SMFs (p < 0.05), the expression of several visual and neurodevelopmental genes (p < 0.05) was generally downregulated in the eyeball.

CONCLUSIONS

Our findings suggest that exposure to ultra-high SMFs, especially the gradient SMFs, may have adverse effects on embryonic development, which should cause some attention to the future application of ultra-high field MRIs.

CLINICAL RELEVANCE STATEMENT

As technology advances, it is conceivable that very strong magnetic fields may be adapted for use in medical imaging. Possible dangers associated with these higher Tesla fields need to be considered and evaluated prior to human use.

KEY POINTS

Ultra-High static magnetic field may affect early embryonic development. High strength gradient static magnetic field exposure impacted zebrafish embryonic development. The application of very strong magnetic fields for MR technologies needs to be carefully evaluated.

Telomerase reverse transcriptase protects against diabetic kidney disease by promoting AMPK/PGC-1a-regulated mitochondrial energy homeostasis

Disordered glucose and lipid metabolism, coupled with disturbed mitochondrial bioenergetics, are pivotal in the initiation and development of diabetic kidney disease (DKD). While the essential role of telomerase reverse transcriptase (TERT) in regulating mitochondrial function in the cardiovascular system has been recognized, its specific function in maintaining mitochondrial homeostasis in DKD remains unclear. This study aimed to explore how TERT regulates mitochondrial function and the underlying mechanisms. In vitro, human renal proximal tubular HK-2 cells exposed to high glucose/high fat (HG/HF) presented significant downregulation of TERT and AMPK dephosphorylation. This led to decreased ATP production, altered NAD+/NADH ratios, reduced mitochondrial complex activities, increased mitochondrial dysfunction, lipid accumulation, and reactive oxygen species (ROS) production. Knockdown of TERT (si-TERT) further exacerbated mitochondrial dysfunction, decreased mitochondrial membrane potential, and lowered levels of cellular oxidative phosphorylation and glycolysis, as determined via a Seahorse X24 flux analyzer. Conversely, mitochondrial dysfunction was significantly alleviated after pcDNA-TERT plasmid transfection and adeno-associated virus (AAV) 9-TERT gene therapy in vivo. Notably, treatment with an AMPK inhibitor, activator, and si-PGC-1a (peroxisome proliferator-activated receptor γ coactivator-1α), resulted in mitochondrial dysfunction and decreased expression of genes related to energy metabolism and mitochondrial biogenesis. Our findings reveal that TERT protects mitochondrial function and homeostasis by partially activating the AMPK/PGC-1a signaling pathway. These results establish a crucial foundation for understanding TERT's critical role inmitochondrial regulation and its protective effect on DKD.

Rotating magnetic field inhibits Aβ protein aggregation and alleviates cognitive impairment in Alzheimer's disease mice

Amyloid beta (Aβ) monomers aggregate to form fibrils and amyloid plaques, which are critical mechanisms in the pathogenesis of Alzheimer's disease (AD). Given the important role of Aβ1-42 aggregation in plaque formation, leading to brain lesions and cognitive impairment, numerous studies have aimed to reduce Aβ aggregation and slow AD progression. The diphenylalanine (FF) sequence is critical for amyloid aggregation, and magnetic fields can affect peptide alignment due to the diamagnetic anisotropy of aromatic rings. In this study, we examined the effects of a moderate-intensity rotating magnetic field (RMF) on Aβ aggregation and AD pathogenesis. Results indicated that the RMF directly inhibited Aβ amyloid fibril formation and reduced Aβ-induced cytotoxicity in neural cells in vitro. Using the AD mouse model APP/PS1, RMF restored motor abilities to healthy control levels and significantly alleviated cognitive impairments, including exploration and spatial and non-spatial memory abilities. Tissue examinations demonstrated that RMF reduced amyloid plaque accumulation, attenuated microglial activation, and reduced oxidative stress in the APP/PS1 mouse brain. These findings suggest that RMF holds considerable potential as a non-invasive, high-penetration physical approach for AD treatment.

Melatonin suppresses atherosclerosis by ferroptosis inhibition via activating NRF2 pathway

Melatonin (MLT), a conserved small indole compound, exhibits anti-inflammatory and antioxidant properties, contributing to its cardioprotective effects. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is associated with atherosclerosis disease risk, and is known as an atherosclerosis risk biomarker. This study aimed to investigate the impact of MLT on Lp-PLA2 expression in the atherosclerotic process and explore the underlying mechanisms involved. In vivo, ApoE-/- mice were fed a high-fat diet, with or without MLT administration, after which the plaque area and collagen content were assessed. Macrophages were pretreated with MLT combined with ox-LDL, and the levels of ferroptosis-related proteins, NRF2 activation, mitochondrial function, and oxidative stress were measured. MLT administration significantly attenuated atherosclerotic plaque progression, as evidenced by decreased plaque area and increased collagen. Compared with those in the high-fat diet (HD) group, the levels of glutathione peroxidase 4 (GPX4) and SLC7A11 (xCT, a cystine/glutamate transporter) in atherosclerotic root macrophages were significantly increased in the MLT group. In vitro, MLT activated the nuclear factor-E2-related Factor 2 (NRF2)/SLC7A11/GPX4 signaling pathway, enhancing antioxidant capacity while reducing lipid peroxidation and suppressing Lp-PLA2 expression in macrophages. Moreover, MLT reversed ox-LDL-induced ferroptosis, through the use of ferrostatin-1 (a ferroptosis inhibitor) and/or erastin (a ferroptosis activator). Furthermore, the protective effects of MLT on Lp-PLA2 expression, antioxidant capacity, lipid peroxidation, and ferroptosis were decreased in ML385 (a specific NRF2 inhibitor)-treated macrophages and in AAV-sh-NRF2 treated ApoE-/- mice. MLT suppresses Lp-PLA2 expression and atherosclerosis processes by inhibiting macrophage ferroptosis and partially activating the NRF2 pathway.

Acetaminophen overdose-induced acute liver injury can be alleviated by static magnetic field

Acetaminophen (APAP), the most frequently used mild analgesic and antipyretic drug worldwide, is implicated in causing 46% of all acute liver failures in the USA and between 40% and 70% in Europe. The predominant pharmacological intervention approved for mitigating such overdose is the antioxidant N-acetylcysteine (NAC); however, its efficacy is limited in cases of advanced liver injury or when administered at a late stage. In the current study, we discovered that treatment with a moderate intensity static magnetic field (SMF) notably reduced the mortality rate in mice subjected to high-dose APAP from 40% to 0%, proving effective at both the initial liver injury stage and the subsequent recovery stage. During the early phase of liver injury, SMF markedly reduced APAP-induced oxidative stress, free radicals, and liver damage, resulting in a reduction in multiple oxidative stress markers and an increase in the antioxidant glutathione (GSH). During the later stage of liver recovery, application of vertically downward SMF increased DNA synthesis and hepatocyte proliferation. Moreover, the combination of NAC and SMF significantly mitigated liver damage induced by high-dose APAP and increased liver recovery, even 24 h post overdose, when the effectiveness of NAC alone substantially declines. Overall, this study provides a non-invasive non-pharmaceutical tool that offers dual benefits in the injury and repair stages following APAP overdose. Of note, this tool can work as an alternative to or in combination with NAC to prevent or minimize liver damage induced by APAP, and potentially other toxic overdoses.

A safety study on ultra‑high or moderate static magnetic fields combined with platycodin D against lung cancer

Due to the serious side effects of chemotherapy drugs against lung cancer, and the antitumor properties and high safety of magnetic fields, the present study combined moderate or ultra-high intensity statics magnetic fields (SMFs) with platycodin D (PD) to explore the antitumor efficiency and biosafety. The antitumor effects of PD with or without moderate and ultra-high SMFs on A549 cells bearing mice were compared. Mouse body weight, food/water intake, hematology routine, blood biochemistry, tumor weight and tissues hematoxylin and eosin (H&E) staining were examined. Behavior was measured using the elevated plus maze, open field and vital signs tests. The combined targets of PD and SMFs were detected using RNA-sequencing (RNA-seq). The results showed that the antitumor effect of 22 Tesla (T) SMF group was 3.6-fold higher compared with that of the 2 mg/kg PD group (tumor growth inhibition=10.08%), while the antitumor effect of 150 mT SMF was only 1.56-fold higher compared with that of PD. Although PD reduced the food intake, there was no significant difference in body weight, water intake or food consumption among PD and SMF groups. Behavioral results indicated that PD ameliorated dysphoria in mice, but SMFs reduced this effect. However, no significant abnormalities were found in routine blood, blood biochemistry test, H&E staining or organ index, except renal index which was reduced by PD with or without SMFs. RNA-sequencing (RNA-seq) demonstrated that SMFs and PD synergistically targeted the expression of genes associated with tumor growth, inflammation and neurological disease. The present study showed the antitumor efficacy and biosafety of moderate or ultra-high SMF combined with PD, which exhibited only few side effects in the treatment of lung cancer, thus supporting further research for the clinical application of magnetic fields.

Ultra-high static magnetic fields cause immunosuppression through disrupting B-cell peripheral differentiation and negatively regulating BCR signaling

To increase the imaging resolution and detection capability, the field strength of static magnetic fields (SMFs) in magnetic resonance imaging (MRI) has significantly increased in the past few decades. However, research on the side effects of high magnetic field is still very inadequate and the effects of SMF above 1 T (Tesla) on B cells have never been reported. Here, we show that 33.0 T ultra-high SMF exposure causes immunosuppression and disrupts B cell differentiation and signaling. 33.0 T SMF treatment resulted in disturbance of B cell peripheral differentiation and antibody secretion and reduced the expression of IgM on B cell membrane, and these might be intensity dependent. In addition, mice exposed to 33.0 T SMF showed inhibition on early activation of B cells, including B cell spreading, B cell receptor clustering and signalosome recruitment, and depression of both positive and negative molecules in the proximal BCR signaling, as well as impaired actin reorganization. Sequencing and gene enrichment analysis showed that SMF stimulation also affects splenic B cells' transcriptome and metabolic pathways. Therefore, in the clinical application of MRI, we should consider the influence of SMF on the immune system and choose the optimal intensity for treatment.