Discussion
When considering this hypothesis, one may also consider out of an abundance of caution as to whether injection, ingestion, or other exposure to substances containing component(s) of the above described lipid-carrier initiator unit could, in a percentage of those exposed, lead to initiation of protein misfolding or to the spread and propagation of existing misfolded protein presently localized at the site of exposure, and ultimately lead to the development of clinical prion disease. This outcome might be considered of theoretical concern even if only one of the above components of the lipid-carrier initiator prion unit is delivered as a result of exogenous, environmental, or iatrogenic intervention, because the others may be present in vivo already due to natural conditions in the exposed tissue. In addition, possible protein-misfolding related effects may be considered when assessing and optimizing safety of the many liposomal and nanoparticle products that are being developed in modern science.