Phagocytosis of latex beads by a human monocytic Mono Mac 6 cell line and effects of low-frequency electromagnetic field interaction

Some studies have shown that electromagnetic fields (EMFs) may impact immune response cells and their functions. The first stage of the defense from pathogens is innate immunity encompassing phagocytosis and phagocytosis-related intracellular effects. Our work aimed to determine the influence of a low-frequency electromagnetic field (7 Hz, 30 mT_rms) on the phagocytosis process of latex beads (LBs), the production of reactive oxygen species (ROS), and viability changes in a human monocytic Mono Mac 6 (MM6) cell line as an experimental model of the phagocytosing cells in in vitro cell culture conditions. For these purposes, cells were firstly activated with infectious agents such as lipopolysaccharide (LPS), Staphylococcal enterotoxin B (SEB), or the proliferatory agent phytohaemagglutinin (PHA), and then a phagocytosis test was performed. Cell viability and range of phagocytosis of latex beads by MM6 cells were measured by flow cytometry, and the level of ROS was evaluated with the use of a cytochrome C reduction test. The obtained results revealed that applied EMF exposure mainly increased the necrosis parameter of cell death when they were pre-stimulated with SEB as an infectious factor and subsequently phagocytosed LBs (P=0.001). Prestimulation with other agents like LPS or PHA preceding phagocytosis resulted in no statistically significant changes in cell death parameters. The level of ROS depended on the used stimulatory agent, phagocytosis, and/or EMF exposure. The obtained effects for EMF exposure indicated only a slight decrease in the ROS level for cells phagocytosing latex beads and being treated with SEB or PHA, while the opposite effect was observed for LPS pre-stimulated cells (data not statistically significant). The results concerning the viability of phagocytosing cells, the effectiveness of the phagocytosis process, and the level of radical forms might result from applied EMF parameters like signal waveform, frequency, flux density, and especially single EMF exposure.

Urinary neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, uromodulin, and cystatin C concentrations in an experimental rat model of ascending acute kidney injury induced by pyelonephritis

Recent evidence suggests that neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin C (CysC), uromodulin (UMOD), and some interleukins (IL-6 and IL-18) can be considered as diagnostic markers of acute kidney injury (AKI). The aim of this study was to verify the applicability of four urinary (u) markers, namely uNGAL, uKIM-1, uCysC, and uUMOD, for the diagnosis of ascending AKI induced by bacterial pyelonephritis. The study included 30 female rats that were divided into three groups (n = 10 each) and were inoculated transurethrally with various doses of Escherichia coli to induce isolated pyelonephritis (group 1, 10⁵ CFU/ml), pyelonephritis-induced AKI (group 2, 10⁷ CFU/ml), or AKI and urosepsis (group 3, 10⁹ CFU/ml). The inoculate contained a highly virulent E. coli strain isolated from a patient with pyelonephritis. Urine samples were obtained prior to the inoculation and 7, 14, and 21 days thereafter. The concentrations of all assessed proteins were determined in the urine samples by ELISA. All the study groups showed elevated concentrations of uNGAL and uCysC at all study time points. The concentrations of uKIM-1 in group 1 were the same as that at the baseline, whereas it was elevated in groups 2 and 3 at all study time points. The concentrations of uUMOD in groups 1 and 2 tended to decrease with the time from inoculation, whereas it rapidly increased in group 3 at 21 days postinfection. uKIM-1 seems to be the only marker of ascending AKI associated with urinary tract infection. Elevated concentrations of uNGAL, uCysC, and uUMOD were found in both AKI and isolated pyelonephritis. Thus, it can be concluded that none of these markers can be used as a single diagnostic marker of ascending AKI, as it may produce false-negative results, leading to incorrect diagnosis, lack of adequate treatment, and increased mortality risk.

Changes in U937 cell viability induced by stress factors - possible role of calmodulin

Current studies were aimed to elucidate influence of magnetic field (MF) stimulation on cell viability and its effect on expression of calmodulin (CaM) and Hsp70 protein which plays a role of cell stress indicator and is a Ca²⁺-dependent CaM-binding protein. For the experimental model we have chosen U937 cell line exposed to chemical- and/or physical stress factors. Puromycin (PMC) was used as a chemical apoptosis inducer. Alternating (AC) (6.5_rms mT, 35 Hz) magnetic field combined with 6 mT static (DC) component, or pulsed electromagnetic field (45 ± 5)mT, 50 Hz (PEMF) acted as physical stressors. Cell viability was assessed by flow cytometry, and the Western blot analysis was carried out for CaM and Hsp70 levels in cytosolic extracts of U937 cells. Cell viability in samples exposed to MF alone did not differ from sham sample, for both types of MF exposure systems. Simultaneous action of MF and PMC influenced cell viability in type of MF stimulation-dependent manner. In contrast to PEMF + PMC stimulated samples, combination of ACDCMF with PMC enhanced cell death compared to PMC control. The observed changes in cell viability were correlated with changes in level of CaM and Hsp70 proteins. Immunoblots have shown, that cytosolic content of both CaM and Hsp70 proteins was enhanced in PMC-treated sample, and further elevated for ACDCMF + PMC. For PEMF + PMC stimulated samples, level of CaM was reduced compared to PMC-treated sample. The results suggest that the changes in expression of CaM and CaM-dependent proteins might modulate effectiveness of cell death under stimulation with MF and/or cytotoxic agents.

Changes in viability of rat adipose-derived stem cells isolated from abdominal/perinuclear adipose tissue stimulated with pulsed electromagnetic field

Previous experiments demonstrated that low-frequency electromagnetic field (LF-EMF) may activate cellular death pathways in proliferating cells. Therefore, we hypothesized that LF-EMF may also influence viability of highly proliferating undifferentiated adipose-derived stem cells. Obesity is classified as a civilization disease; its etiopathogenesis is presumed to include both genetic predisposition and influence of modified environmental factors, such as unbalanced diet with excess calories and/or too low physical activity. Obesity may lead to a number of metabolic disorders, including type 2 diabetes mellitus, cardiovascular diseases (associated with atherosclerosis) related to primary hypertension and ischemic heart disease, myocardial infarction and other complications. The aim of this study was to verify if LF-EMF alters viability parameters of adipose-derived stem cells (ADSCs) isolated from rats, cultured in vitro and exposed to pulsed electromagnetic field (PEMF; 7 Hz, 30 mT). ADSCs were obtained from healthy rats and animals with experimentally-induced obesity, both males and females, pups and adults. The animals were fed with chow with either low (LF diet) or high fat content (HF diet) for 21 days. Then, ADSCs were isolated from extracted adipose tissue and used to establish cell cultures. ADSCs from the first passage were exposed to PEMF three times, 4 hours per exposure, at 24-h intervals (experimentally developed protocol of PEMF stimulation). 24 hours after the last exposure to PEMF, viability parameters of ADSCs were analyzed by flow cytometry (FCM). The study demonstrated that LF diet exerted a protective effect on PEMF-exposed ADSCs, especially in the case of male and female pups. In turn, the proportion of early apoptotic cells in PEMF-treated ADSC cultures from adult female rats maintained on HF diet turned out to be significantly higher than in other experimental groups.

Pulsed electromagnetic field affects intrinsic and endoplasmatic reticulum apoptosis induction pathways in MonoMac6 cell line culture

Current studies were aimed to elucidate influence of pulsed electromagnetic field stimulation on cell viability and apoptosis induction pathways. For the experimental model we have chosen monocytic cell line MonoMac6 and several apoptosis inducers with different mechanism of death induction like puromycin, colchicine, cyclophosphamide, minocycline and hydrogen peroxide. MonoMac6 cell line was grown at density 1x10(5) cells/well in 96-well culture plates. To induce cell death cell cultures were treated with different apoptosis inducers like puromycin, colchicine, cyclophosphamide, minocycline, hydrogen peroxide and at the same time with pulsed electromagnetic field 50 Hz, 45±5 mT (PEMF) for 4 hour per each stimulation, three times, in 24 hours intervals. Afterwards, cells were harvested for flow cytometry analysis of cell viability measured by annexin V-APC labeled and propidium iodide staining. Expression of apoptosis related genes was evaluated by semi quantitative reverse transcription (RT)-PCR assay. NuPAGE Novex Western blot analysis was carried out for apoptosis inducing factor (AIF) abundance in cytosolic and nuclear extracts of MonoMac6 cells. Puromycin, colchicine and minocycline activated cells and simultaneously treated with PEMF have shown out diminished percentage of annexinV positive (AnV+) cells comparing to controls without PEMF stimulation. MonaMac6 cells puromycin/colchicyne and PEMF treated were to a higher extent double stained (AnV+,PI+), which means increased late apoptotic as well as necrotic (PI+) cells, than non-stimulated controls. On the other hand, minocycline activated cells prior to PEMF treatment showed diminished amount of apoptotic and necrotic (annexin V, annexin V and propidium iodide, propidium iodide positive staining) cells. The opposite effect of PEMF on the percentage of annexin V positively stained cells has been achieved after treatment of MonoMac6 culture with cyclophoshamide and hydrogen peroxide. PEMF enhanced early phase of apoptosis induced by both apoptosis inducing agents. The analysis of expression of the apoptosis related genes in MonoMac6 cultures treated with puromycin and exposed to PEMF performed in reverse transcription of polymerase chain reaction (PCR) assay has shown changes in mRNA of genes engaged in intrinsic apoptotic pathway and pathway with AIF abundance. The most influenced was expression of gene belonging to pro-apoptotic family of Bcl-2 and AIF agent. Examination of immunoblots developed with anti-AIF antibody showed that cytosol content of AIF protein was diminished after puromycin and PEMF treatment of MonoMac6 cells. The obtained results indicate that PEMF affects induction of apoptosis in MonoMac6 cells stimulated to death with inducing agents to a different extent. Main finding of the current results is that, PEMF stimulation of MonoMac6 cells simultaneously treated with puromycin caused changes in the Bcl-family genes expression as well as in caspase independent pathway of apoptosis inducing factor (AIF).

Pulsating electromagnetic field stimulation of urothelial cells induces apoptosis and diminishes necrosis: new insight to magnetic therapy in urology

The evidence of electromagnetic therapy (EMT) efficacy in stress and/or urge urinary incontinence, as well as in detrusor overactivity is generally lacking in the literature. The potential EMT action of neuromuscular tissue depolarization has been described. Because there is no data on the influence of pulsating electromagnetic fields (PEMF) on the urothelium, we evaluated the effect of PEMF stimulation on rat urothelial cultured cells (RUCC). In our study 15 Wistar rats were used for RUCC preparation. RUCC were exposed to PEMF (50 Hz, 45±5 mT) three times for 4 hours each with 24-hour intervals. The unexposed RUCC was in the same incubator, but in a distance of 35 cm from the PEMF generator. Annexin V-APC (AnV+) labelled was used to determine the percentage of apoptotic cells and propidium iodide (PI+), as standard flow cytometric viability probe to distinguish necrotic cells from viable ones. The results are presented in percentage values. The flow cytometric analysis was carried out on a FACS calibur flow cytometer using Cell-Quest software. In PEMF-unstimulated RUCC, the percentage of AnV+, PI+, and AnV+PI+ positive cells were 1.24±0.34%, 11.03±1.55%, and 12.43±1.96%, respectively. The percentages of AnV+, PI+, and AnV+PI+ positive cells obtained after PEMF stimulation were 1.45±0.16% (p=0.027), 7.03±1.76% (p<0.001), and 9.48±3.40% (p=0.003), respectively. The PEMF stimulation of RUCC induces apoptosis (increase of AnV+ cells) and inhibits necrosis (decrease of PI+ cells) of urothelial cells. This leads us to the conclusion that a low-frequency pulsating electromagnetic field stimulation induces apoptosis and diminishes necrosis of rat urothelial cells in culture.

Pulsating electromagnetic field stimulation prevents cell death of puromycin treated U937 cell line

Aim of study was to verify whether pulsating electromagnetic field (PEMF) can affect cancer cells proliferation and death. U937 human lymphoid cell line at densities starting from 1 x 10(6) cells/ml to 0.0625 x 10(6) cells/ml, were exposed to a pulsating magnetic field 50 Hz, 45+/-5 mT three times for 3 h per each stimulation with 24 h intervals. Proliferation has been studied by counting number of cells stimulated and non-stimulated by PEMF during four days of cultivation. Viability of cells was analyzed by APC labeled Annexin V and 7-AAD (7-amino-actinomycin D) dye binding and flow cytometry. Growing densities of cells increase cell death in cultures of U937 cells. PEMF exposition decreased amount of cells only in higher densities. Measurement of Annexin V binding and 7-AAD dye incorporation has shown that density-induced cell death corresponds with decrease of proliferation activity. PEMF potentiated density-induced death both apoptosis and necrosis. The strongest influence of PEMF has been found for 1 x 10(6)cells/ml and 0.5 x 10(6) cells/ml density. To eliminate density effect on cell death, for further studies density 0.25 x 10(6) cells/ml was chosen. Puromycin, a telomerase inhibitor, was used as a cell death inducer at concentration 100 microg/ml. Combined interaction of three doses of puromycin and three fold PEMF interaction resulted in a reduced of apoptosis by 24,7% and necrosis by 13%. PEMF protects U937 cells against puromycin- induced cell death. PEMF effects on the human lymphoid cell line depends upon cell density. Increased density induced cells death and on the other hand prevented cells death induced by puromycin.

Magnetically induced vagus nerve stimulation and feeding behavior in rats

Vagus nerve (VN) contribute to the bidirectional communication between the gastrointestinal tract and the central nervous system. Stimulation of the VN by a magnetically-driven solenoid with parameters similar to those during food-induced stomach distension has been thought to mimic short-term signaling of satiety and suppress food intake. In this study, the determination of optimal parameters of vagal neuro-modulation to achieve decreased food intake with a resulting reduction in body mass of rats is explored as therapy to treat obesity. The experimental design consisted of three groups of obese adult male Wistar rats: Group 1: VEMF - with solenoid's electrodes placed on the left VN in the magnetic field exposure (MFE); Group 2: EMF - without solenoid's electrodes on the VN in MFE; Group 3: CON - without solenoid's electrodes on the VN outside the MFE. This study suggests that the rats with solenoid's electrodes placed on the left VN significantly decreased their food intake, weight gain and serum leptin concentrations when compared to that of the CON group. PP levels were found to be higher in the VEMF group when compared to the controls groups. It was found that the most effective parameters of vagal stimulation on eating behavior were 3631, 7861, 14523 A(2) x h/m(2). The magnetic field by unknown mechanisms also influences feeding behavior. This study suggests that vago-vagal reflexes are involved in the feeding homeostasis and that neuromodulation might be an effective method for managing obesity. Further studies are required to confirm these effects in humans.

Alveolar macrophages of children suffering from recurrent infections of respiratory tract are less efficient in eliminating apoptotic neutrophils

During bacterial infections of the respiratory tract, neutrophils (PMN) are recruited to the lung by various mechanisms, including production of interleukin-8 (IL-8) by alveolar macrophages (AM). After fulfilling their defense function, PMN become apoptotic and have to be disposed of by AM to prevent local damage to the lung tissue by oxygen species and proteolytic enzymes. We measured the levels of IL-8 in the bronchoalveolar lavage (BAL) and the ability of AM to engulf senescent PMN in a groups of children with and without recurrent infections of the respiratory tract. The IL-8 level was measured by enzyme-linked immunosorbent assay (ELISA). The phagocytosis of apoptotic neutrophils was evaluated microscopically by the presence of myeloperoxidase positive material in AM before and after 1 h of incubation with senescent PMN. The data show that children suffering from recurrent infections have increased IL-8 in BAL and that their AM have a lower ability to engulf apoptotic PMN in vitro. Furthermore, the proportion of annexin V-binding cells was higher in BAL of children with recurrent infections of the respiratory tract than in normal controls.