Original Article: https://doi.org/10.1371/journal.pone.0238533
- Researchers tested whether placebo effects can be monitored and predicted by plasma proteins.
- Participants were exposed to a nauseating stimulus on two separate days.
- Participants were randomly assigned to placebo treatment or no treatment on the second day.
- Significant placebo effects on nausea, motion sickness, and gastric activity in females could be verified.
- Using a type of mass spectrometry, 74 differentially regulated proteins were identified that correlates with the placebo effect.
- Gene ontology enrichment analyses identified acute-phase proteins and microinflammatory proteins to be involved.
- Gene ontology provides a framework and set of concepts for describing the functions of gene products from all organisms.
- Acute phase proteins are plasma proteins synthesized in the liver whose concentrations increase or decrease during inflammation.
- The identified gene ontology signatures predicted day-adjusted scores of nausea indices in the placebo group.
- Researchers also performed gene ontology enrichment analyses of specific plasma proteins predictable by the experimental factors or their interactions and identified ‘grooming behavior’ as an important hit.
- Graphical analysis allowed to identify plasma proteins differentiating placebo responders from non-responders, comprising immunoglobulins and proteins involved in oxidation reduction processes and complement activation.
- The study of plasma proteins is a promising tool to identify molecular correlation and prediction of the placebo effect in humans.
Keywords: can placebo effect be monitored, can we measure the effect of placebo, placebo effect measurement, tracking placebo effect, monitoring placebo effect, detection of placebo effect