I never read the sports pages. What, never? Well, hardly ever….An article in the New York Times sports page did catch my eye because it was about CTE. CTE stands for chronic traumatic encephalopathy, or what happens when your head gets repeatedly bashed on the football field.
CTE is so pervasive among professional football players that a neuropathologist examined the brains of 111 NFL players and found CTE in….110. All of these players were deceased, because that’s the only way you can conclusively confirm a diagnosis of CTE. Same goes for Alzheimer’s and Parkinson’s.
All three of these neurological diseases are characterized by clumps of runaway proteins clogging up the brain: tau for CTE and Alzheimer’s, and alpha-synuclein for Parkinson’s. These clumps can’t be seen until the patient is dead. The clumps are what Dr. Alois Alzheimer saw, way back in his lab in Munich in 1906. Finding a biomarker that can accurately diagnose these diseases in a living patient is the Holy Grail of neurological research.
So that’s what caught my eye about this article. The researchers used positron emission tomography (PET) scans on living patients and found “elevated amounts of abnormal tau protein”. However, the authors of the study and outside experts stressed that this tau imaging is far from a diagnostic test for CTE, which is “likely years away”.
Another intriguing thing in this article is a term that is new to me: “ligand“. Ligand is a molecule that binds to proteins (in this case, tau), making them easier to see in a PET scan. The Wikipedia entry helpfully says, “Radioligands are radioisotope labeled compounds used in vivo as tracers in PET studies…” A company called Avid Radiopharmaceuticals has successfully developed a ligand for tau and participated in (and partially funded) this study.
And….how exciting!….Avid is also working on a ligand for detecting Parkinson’s: 18F-AV-133. (Catchy name- guess it’s too early for the marketing department to get involved.) I found a clinical trial on this ligand listed in an NIH database which indicated the trial started 2012 and ended 2016….but I have been unable to find the results. I did find that AV-133 (the “18F” seems to have been dropped) is part of a mammoth study searching for that biomarker Holy Grail, Parkinson’s Progression Markers Initiative, funded by the Michael J. Fox Foundation. More about PPMI in a future blog.
YouTube extra! “What Never? No Never! What Never? Well, hardly ever” from Gilbert and Sullivan’s HMS Pinafore.