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Premature Claims for Neurotrophic Factors

Scientific medicine is not easy. By this point we have largely picked the low hanging fruit, and continued improvements are mostly incremental and hard won. In order to get the most out of our limited research dollars, and optimize medical practice with the safest and most effective treatments, we need to use all available scientific evidence in the proper way. That is the essence of SBM.

There are those, however, that misuse or abuse the scientific evidence — whether to promote an ideology, out of innocent ignorance, or for nefarious purposes. In order to be truly science-based a medical intervention should be plausible, or at least not implausible, based upon basic science evidence, and it should actually be safe and effective when tested in people. Therefore, medical practices can fail to be scientific for one of two broad reasons: they can be scientifically implausible, or they can lack proper clinical evidence for safety and efficacy (or even have evidence for lack of efficacy). Some modalities (like homeopathy) fail on both counts.

The more pernicious medical claims are those that seem highly plausible, that can be extrapolated from basic science, but simply lack adequate clinical evidence. Stem cell clinics are an example — they can easily dazzle desperate patients with scientific descriptions of how stem cells work, and even cite published basic-science papers showing the potential of this technology. But what they cannot do is provide clinical evidence that the specific intervention they are offering is safe and effective for the specific disease or condition they are treating.

I recently came across another example of this type of failure — the promotion of neurotrophic factors for autism and other neurodevelopmental disorders. One center, the Neurorecovery Center Edelfo, specializes in this claim.

Neurotrophic factors are generally proteins that bind to cells and cause them to grow, proliferate, or just maintain their functionality. Some nervous system cells would die without a steady supply of the needed neurotrophic factors. The discovery of neurotrophic factors and their role in nervous system function was certainly very important to our understanding of neurological diseases. This knowledge has also led to a great deal of speculation about the potential of neurotrophic factors in treating neurological diseases.

After a couple decades of clinical research, however, the reality has not lived up to the promise. As is often the case, highly plausible ideas do not pan out in clinical research. Several neurotrophic factors, for example have been studied in diseases like ALS without any measurable clinical benefit. They are just another reminder that the body is complex, and even when we have a very compelling picture of why a treatment should work, that picture is almost certainly incomplete. We cannot know what the net effect will be of a treatment until we do rigorous clinical trials.

Another way to look at this is that the body has evolved complex mechanisms of self-regulation. It is not easy to push or pull on one piece of this complex system and predict the net effect. There are many reasons why a treatment that we predict should work, doesn’t.

Edelfo is doing what many similar clinics or supplement marketers do — making simplistic extrapolations from the basic science to clinical claims, without supporting those claims with clinical evidence. They cite basic science research to give the false impression they are science-based. For example, they write on their website:

BDNF has shown to have a neurotrophic effect in serotoninergic and dopaminergic neurons, but also in glutamatergic neurons of the hippocampus and the sensory regions like pain, touch and hearing. BDNF also contributes to the maturation of GABAergic neurons, so it can also be useful in bipolar disorders, schizophrenia, ADD, memory, neuronal deficits that affect audition, sensitivity, etc.
GDNF has shown a specific effect in dopaminergic neurons and secondly in motor neurons, so it can be very useful in ADD, where a hypo development of the dopaminergic circuit has been shown, although there are other types of ADD that are generated by alterations in other regions like the frontal lobe, basal ganglia, etc. GDNF can also be useful in Parkinson’s, where there is a severe loss of the dopaminergic neurons of the substantia nigra and in motor problems, where experimental studies performed in rodents with motor damage have shown that the GDNF favors the axonal growth of motor neurons and improves the functional recovery.

Edelfo uses a diagnostic method based upon EEG to then design a nutritional supplement for their specific customers. The claims above are an excellent example of the type of pseudoscientific deception I am describing.  There is indeed a great deal of interest in GDNF for Parkinson’s disease. Animals studies have shown promise, but human studies have been negative. The problem is probably due to getting the GDNF to the target tissue.

GDNF is a protein. If you eat a protein it will be broken down into amino acids and used as food — it will not get into the bloodstream unaltered. This is why protein-based drugs typically need to be given intravenously, to bypass the stomach. GDNF has even more difficulty, however, since it also needs to cross the blood brain barrier — a protective barrier around blood vessels in the brain evolved to specifically regulate what gets into the brain. To overcome this issue researchers have used one of two methods — they either use gene therapy to insert GDNF producing genes into brain cells, or they use a continuous infusion of GDNF into the cerebrospinal fluid (CSF).

There are rather extreme methods of introducing a drug to the body, but they are necessary. And even still, researchers speculate that the CSF infusions used in human trials were not sufficient to get GDNF to the cells in the brain that are the target of treatment.

It is with these types of issues that pseudoscientific treatments often fail — bioavailability and pharmacokinetics. Does the substance get into the body, and what happens to it once it does? Basing claims for a nutritional supplement on the activity of BDNF is highly deceptive. It certainly can sound compelling to a non-expert, but the claims utterly fail when closely examined. The same, by the way, can be said for BDNF, which is also a protein.

Edelfo’s use of EEG (electroencephalogram), visual and auditory evoked potentials (VEP, AEP) is also questionable. These modalities are all legitimate methods of research and diagnosis, but they need to be specifically validated for each specific clinical use. They are therefore ripe for exploitation — they can be used inappropriately to give the impression of high-tech diagnostic procedure without the evidence to support the specific application.

The published research in this area is complex and mixed. In autism, for example, studies do show that there is a statistical difference in AEPs between autistic and typical children. This does not mean, however, that the test has specificity or sensitivity in the diagnosis of an individual. This is a common misuse of scientific evidence: using group comparisons and applying them to the individual. A different kind of study is necessary to see what predictive value the test has when applied to an individual. There are therefore many diagnostic modalities that are useful for research, but are not used clinically for this reason.

To further bolster their claims Edelfo does publish a few in-house studies. The quality of these studies is so low, however, that they are useless for anything but marketing. In a study of another neurotrophic factor, FGF2, in autism, the study was published in Defeat Autism Now (DAN), which is a dubious site dedicated to biological treatments for autism and notorious for making pseudoscientific claims. That aside, the study itself is fatally flawed in numerous ways, including using very low subject numbers and not describing any blinding. These types of studies are almost guaranteed to generate false positive results — again, useful for marketing, but not doing good science.

Conclusion

The public needs to be aware of the types of misleading claims that are made by clinics, centers, and marketers of health products that can seem very scientific when they are not. The use of pre-clinical evidence to make clinical claims, the use of research methods for clinical diagnosis, and the use of supplements without any consideration of bioavailability are chief among them. Patients and their families are cautioned to be skeptical of any clinic or center that claims to offer a unique service. Further, any clinical claims being made should be backed by well-designed clinical trials of the specific claims published in respected peer-reviewed journals.

Anything less than this is likely to be selling false hope, not a legitimate treatment.

Posted in: Herbs & Supplements, Neuroscience/Mental Health, Science and Medicine

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