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The fourth day of BioEM2014 had a very interesting plenary lecture on “Staying in Shape: Membrane Voltage as a Master Regulator of Tissue Shape during Regeneration” presented by Wendy Beane from the Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA.
The short version of the presentation
Bioelectrical (ion flux-mediated) signaling is essential—not just for excitable cells, such as neurons and cardiac muscle, but for all cells. The significance of ion currents, voltage gradients and endogenous electric fields to wound healing, growth and development, and even cancer progression has long been noted. However, historically few researchers have focused on the important roles of bioelectrical signaling in non-excitable cells. This presentation will provide an overview of our current understanding of how membrane voltage and ion flux regulate cell fate, cell proliferation and migration, and organ formation during both embryogenesis and adult tissue regeneration. This will be followed by closer examination of in vivo studies using the awesome regenerative powers of the planarian flatworm, which are able to regrow a complete worm in just 2 weeks from a tiny fragment lacking even brain. These studies have established planaria as one of the first models for investigating regenerative shape, and they reveal that membrane voltage acts as a master shape regulator—determining the position, size and shape of organs during regeneration. Despite our advanced insights into gene regulation, we still cannot explain how changes in individual cells lead to predetermined animal shapes (why a decapitated flatworm always regenerates with the correct “planarian” shape). However, recent data demonstrate that early bioelectrical signaling is essential for coordinating cell communication between old (pre-existing) tissues and newly regenerating ones. Disruption of this signaling leads to worms with significant shape defects, including disproportionate organs and tiny, shrunken heads. These data suggest that reagents regulating ion flux, many of which are already approved for human use, could be adapted to control tissue shape in stem cell-driven regenerative therapies.(for more see Beane et al., 2013, Development, 140:313-322.)
It was a very, very interesting presentation. In my opinion, one of the best at this meeting. What Wendy Beanie made clear is that the “bioelectrical (ion flux-mediated) signaling is essential not just for neurons but for all cells. Ion currents and endogenous electric fields are crucial for wound healing, tissue outgrowth and even cancer“.
The most “disturbing” for me was the information that slight changes in cell membrane potential, leading to depolarization of membrane, can, in developing embryo, completely change the fate of the depolarized area, including stimulation of development in the affected areas of additional organs, like e.g. eye.
This brought to my mind two unknowns:
- Current dosimetry models do not consider cell-level ion fluxes and their ability to affect cell membrane voltage potential dosimetry models are too “crude” for analysis of such subtle morphological structures.
- We have no research on whether RF exposures are able to modify or interfere with normal cellular membrane potentials and affect polarization status of cell membrane. At the same time, there are old studies, from e.g. Astumian and Bohr & Bohr, suggesting that RF exposures can affect aggregation of charged biological macromolecules, e.g. proteins.
Exploration of such phenomena as the effect of RF exposures on charged structures and macromolecules might be the way to find a mechanism of the RF-induced effects; effect that seems to occur in spite of the low energy delivered to the exposed cells.
Following the plenary session was second already session on mechanisms (session 7). In this session were two presentations that demonstrated the difference in studying biological material by physicists and by biologists.
The first study, showing physicists-approach, was on “An improvement method of estimation of cell cytoplasm conductivity using nanosecond pulsed electric fields: Coupling of a microdosimetric model with experiments for a single cell“. The study, attempting to examine conductivity of cell cytoplasm, had two problems. First problem was that the cellular cytoplasm was treated as a uniform medium, what cytoplasm is not due to extensive compartmentalization by membranes forming different type of cytoplasmic organelles. The second problem, of even bigger magnitude, was that during the measurements cells were suspended in supposedly inert medium – solution of sucrose. However, this medium is not biologically inert, and as it was shown in another presentation in the same session, sucrose solution can exert very powerful effects on cells. Effects that might affect cell’s ability to live or to die. Therefore, the measurements of cytoplasmic conductivity, presented in this study, should be looked at with a great caution.
The study demonstrating the impact of sucrose on cells’ life and death was entitled “Actin cytoskeleton and cellular effects of the nanosecond pulsed electric field (nsPEF)“. This very elegant study has shown “[nanosecond] pulses caused cell membrane poration, cell rounding, swelling, and disappearance of bright actin features. Blocking of swelling by isoosmotic addition of sucrose blocked disassembly of actin features. Hence, disintegration of the actin was downstream from nsPEF-induced cell swelling.” This observation shows that sucrose solutions can block even the apoptosis-inducing signals.
These two studies clearly show that the educational background of the scientists affects study design which, in turn, can significantly affect the results of the study. It is worrisome to consider how many research studies (biological or engineering/physical) carry errors because scientists involved had insufficient knowledge and experience and hands-on experience.
Finally, on the last day of the BioEM2014 conference, three presentations got my attention. The first one was the presentation in the session on standards, policy and compliance (session 12) “Intuitive exposure and risk perception of RF EMF“. This study presented results obtained in the European LEXNET project; with aims briefly presented in the abstract “One of the main assumptions of the LEXNET project is that a reduction of the RF EMF exposure will result in more acceptance of wireless communication networks in the public sphere“. The study examined the response of users to the reduction of the safety standards by 50%. The conclusion of the study was “The results suggest that perception of RF EMF risks is only marginally determined by exposure characteristics.”
This result is not surprising. Those who do not care about RF exposures will also not care if the exposures are reduced by 50%. On the other hand, those who are worried about RF exposures, demand much greater reduction than the 50% and inuring whether such reduction will change their attitude is a futile exercise.
There was also a question from the audience, from a scientist employed by the industry, who questioned the existence of projects like LEXNET. In his opinion, any discussion of whether reduction of the exposures, from the current ones, is “dangerous”. In his opinion safety standards provide a sufficient margin for protection of the general public and any discussion about optional or voluntary reductions, to increase general public’s confidence, are bad because they undermine trust in the safety standards. It is a very well-known mantra of the industry. This mantra, however, does not consider the question of the reliability, validity and sufficiency of the current safety standards. As I said many times in my blog and other recent writings, reliability of the safety standards was seriously undermined by the IARC 2011 classification of cell phone radiation as a possible carcinogen.
Industry’s attitude of silencing any debate, on the sufficiency of the safety standards, begins to remind the activities of tobacco and asbestos industries…
The attitude of the industry was seen clearly in the next presentation, delivered by CK. Chou, formerly of Motorola and currently of CK Chou Consulting. Presentation was very forceful in pushing the argument that the current safety standards are valid and that safety standards should consider only science and do not consider attitudes and worries of the general public. In the following brief discussion, the attitude of not considering views of the general public was put in question by Chris Portier. In his opinion, the worries and concerns of the general public should and are incorporated in the safety standards dealing with exposures to chemicals, and the same should apply e.g. to RF.
Last year, at the BioEM2013 in Thessaloniki, one of the hotly debated presentations was from Boris Pasche on cancer treatment using amplitude-modulated at discrete frequencies RF-fields. Pasche is already using this method to treat terminally ill cancer patients and is reporting positive results.
This year, presentation from French scientists led by Yann Percherancier and Bernard Veyret, tested Pasche’s method’s validity in the animal study. The result of the French animal study was negative – scientists were unable to replicate Pashe’s results.
In the following discussion, it was asked and suggested that the results of the French animal study should be published in a peer-reviewed journal. Some scientists in the audience considered Pasche’s results as not supported by the experimental evidence and, therefore, the successful treatment of some patients might be just a spontaneous recovery that happens from time to time and not the result of the treatment.
Bernard Veyret, who presented the study in Cape Town, appeared somewhat uncertain about the publication of the results. Clearly, what he presented, was a pilot study and more experiments would be required to validate the result. As he put it, he did not want to get full-time involved in further animal study aimed at replication of the results of Pasche’s work.
This statement is very worrisome and reminds me of another case from the Bordeaux lab. After my research group published in 2002 findings showing activation of the Hsp27 by RF exposures, group in Bordeaux attempted replication of our results. Using a modified approach, they got a negative results – were unable to replicate our result. They presented the preliminary data at the meeting in Helsinki and… that was the end of the story. They never finished this study and never published it. However, at the meeting in Helsinki, by presenting the preliminary data they put out a doubt about the validity of our observation. They did not bother to finalize the study and publish it in peer-reviewed journal.
Statement from Dr. Veyret, where he does not want to be further and fully involved in replicating Pasche’s results in the animal study, reminds me the story the of Hsp27. Is it so that, yet again, the preliminary results were presented at the scientific meeting, doubts about Pasche’s results were presented and instilled and… the full study will never be completed? Let’s hope that this time the full study will be completed and published, whatever the result of it will be.
BRHP - Between a Rock and a Hard Place 