Interview with Prof. Dr. Patrick Diel
Centre of Preventive Doping Research, Dept. of Molecular and Cellular Sports Medicine, German Sport University Cologne, Cologne, Germany.
Bioanalytic-Update: Dear Prof. Dr. Diel, in a recent publication (Link) to abstract) you described the use of Chimera Biotec's ultra-sensitive Imperacer® assay system to detect potential abuse of anabolic substances and myostatin inhibitors for the purpose of doping. Why do you assume myostatin might be a target for doping abuse?
P. Diel: Myostatin was identified to be a muscle growth inhibitor more than 10 years ago. In transgenic, myostatin-deficient mice or naturally accruing cattle mutants with defects in the myostatin gene enormous skeletal muscle growth is observed. Therefore, several pharmacological companies made use of this knowledge to develop therapies for treatment of muscle dystrophy diseases. Currently different myostatin inhibitors are under investigation in clinical trials. These biotherapeutics can potentially be abused for doping.
Bioanalytic-Update: Is there any evidences for such an abuse yet?
P. Diel: Well, currently no detection method is available for these inhibitors. Hence, their abuse for doping cannot be proven. However, we do have strong indication to believe that inhibition of myostatin A) is potentially effective in doping, and B) corresponding substances are already abused for doping purposes.
Bioanalytic-Update: Can you go into details on why you believe so?
P. Diel: The usual observations mainly - rumours amongst athletes, as well as a number of records and achievements within the athletic community which are physiologically hard to explain.
Bioanalytic-Update: So the World Anti-Doping Agency (WADA) advances the development of a verification procedure even though it is uncertain if myostatin inhibitors are indeed used for doping?
P. Diel: Exactly, it is part of the novel preventive program of WADA not only to react once the abuse is officially exposed as doping procedure, but also to preventively foreclose any misuse via development of detection technologies for medication or pharmacological strategies that have potential for being abused in doping.
Bioanalytic-Update: Does this mean an immunoassay useful as verification procedure for myostatin inhibitors will be available soon?
P. Diel: Unfortunately it is not that easy. Potentially there is a multitude of different means to inhibit myostatin activity. For example, blocking of myostatin receptor, knockout of myostatin activity by titration with artificial, soluble receptor, over-expression of myostatin inhibiting proteins or knockout of myostatin transcripts by means of siRNA, to name just a few possibilities. For detecting each of these manipulations directly, a separate verification procedure would be needed. We are going a different route.
Bioanalytic-Update: And this route would be … ?
P. Diel: Our approach is to detect manipulations of the complex feedback control circuit, which controls myostatin activity in the human body. To do so, alterations in the biological fingerprint of certain biomarkers correlating with myostatin bioactivity need to be carefully monitored.
Bioanalytic-Update: Does the data in your publication describe the development of a verification procedure on the basis of this approach?
P. Diel: Actually, we are not there yet. The data published gives a strong contribution to build up the foundations for such a doping test procedure by careful study on the physiology of these control circuits. Knowledge on how alterations by artificial intervention can be distinguished from natural changes, due for example to training, age- or gender-specific differences, etc., is playing a critical role in the development of such doping tests.
Bioanalytic-Update: How does Chimera’s immunoPCR based Imperacer® ligand-binding assay platform contribute to your doping test concept?
P. Diel: Well, Imperacer® plays an important role because, due to it’s PCR-driven highly-sensitive signal readout, this immunoassay technology enables us to analyze biomarkers for the effect of inhibitors of bioregulatory circuits - like the one for myostation at minuscule concentrations in various biological matrices such as urine, blood or sputum. Immunoassay sensitivity is giving a two-fold benefit here. First, it enables high sample/dilution ratios to minimize matrix effects. Second, the analysis can be carried out with minimal amounts of sample.
Bioanalytic-Update: Isn’t this also possible with classic immunoassays like ELISA or ECL?
P. Diel: In most cases concentration changes of relevant biomarkers can indeed be detected with traditional technologies like ELISA as well. However, much larger volumes of sample material are needed and the possibilities in terms of sample dilution are much more limited compared to Imperacer®. That is fine for research purposes, but not applicable for the use in routine analytics. For example, the collection of blood samples in millilitre amounts means physical stress for the athletes and is not acceptable in needed frequencies. In addition, higher sample volumes are also quite costly and intricate in regard to sample transport and storage logistics.
Bioanalytic-Update: So, readout intrinsic immunoassay sensitivity is employed to enhance assay specificity, matrix tolerance and sample consumption simply by sample dilution?
P. Diel: Basically, yes. Imperacer® enables antibody binding under better controllable buffer conditions, instead of binding within complex biological matrices with unknown varieties of interfering matrix components. This leads to better assay specificity and sensitivity, especially in rather challenging matrices like urine or sputum, while at the same time minimizing sample consumption.
Bioanalytic-Update: Prof. Diel, thank you for these very interesting insights into your scientific work. Good luck in your on-going quest to develop means to detect current as well as future, doping techniques.
P. Diel: My pleasure, thank you.
