Study type: Medical/biological study (experimental study)

Very low intensity alternating current decreases cell proliferation. med./bio.

Published in: Glia 2005; 51 (1): 65-72

Aim of study (acc. to author)

To test the efficacy of very low frequency alternating current (AC) in altering cell cycle of normal and neoplastic cells as novel electrical approach for the treatment of neoplasms or other hyperplastic disorders.

Background/further details

Epileptic astrocyte cultures are established from human cortical tissue of patients undergoing temporal lobectomies to relieve medically intractable seizure.
A possible interaction between cell cycle and KIR3.2 (inward rectifier potassium channel) channel activity is suggested.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 10 Hz
Exposure duration: continuous for 3 to 5 days
cells were stimulated with 0.17 µA
-
Exposure 2: 25 Hz
Exposure duration: continuous for 3 to 5 days
cells were stimulated with 1.7 µA
-
Exposure 3: 50 Hz
Modulation type: pulsed
Exposure duration: continuous for 3 to 5 days
cells were stimulated with 8.5 µA
Exposure 4: 75 Hz
Exposure duration: continuous for 3 to 5 days
cells were stimulated with 17 µA
-
Exposure 5: 100 Hz
Exposure duration: continuous for 3 to 5 days
cells were stimulated with 170 µA
-

Exposure 1

Main characteristics
Frequency 10 Hz
Type
Waveform
Exposure duration continuous for 3 to 5 days
Additional info cells were stimulated with 0.17 µA
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Setup Cells were grown in 24 well plates. Each plate was located between the electrodes.
Parameters

No parameters are specified for this exposure.

Exposure 2

Main characteristics
Frequency 25 Hz
Type
Waveform
Exposure duration continuous for 3 to 5 days
Additional info cells were stimulated with 1.7 µA
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Parameters

No parameters are specified for this exposure.

Exposure 3

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 3 to 5 days
Additional info cells were stimulated with 8.5 µA
Modulation
Modulation type pulsed
Additional info

32 cycles/pulse, 10 s interval between each pulse

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
current density 3 µA/cm² peak value calculated - at the middle of the well

Exposure 4

Main characteristics
Frequency 75 Hz
Type
Waveform
Exposure duration continuous for 3 to 5 days
Additional info cells were stimulated with 17 µA
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Parameters

No parameters are specified for this exposure.

Exposure 5

Main characteristics
Frequency 100 Hz
Type
Waveform
Exposure duration continuous for 3 to 5 days
Additional info cells were stimulated with 170 µA
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Parameters

No parameters are specified for this exposure.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data show that in the absence of thermal influences, low frequency, low-intensity, alternating current directly affects cell proliferation without a significant deleterious contribution to cell survival. These effects were revealed in normal human cells and in brain and prostate neoplasms, but not in lung cancer. The effects of alternating current stimulation required a permissive role for KIR3.2 potassium channels and were mimicked by raising extracellular potassium concentrations.
Cell death could be achieved at higher alternating current frequencies (>75 Hz) or intensities (>8.5 µA). At lower frequencies/intensities, alternating current stimulation did not cause apoptotic cellular changes.
The results implicate a role for transmembrane potassium fluxes via inward rectifier potassium channels in the regulation of cell cycle. The data suggest a potential clinical application of electrical stimulation to reduce cell proliferation.

Study character:

Study funded by

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