Turns out that several of the main studies about cerebrolysin may have been fraudulent: https://www.science.org/content/article/research-misconduct-finding-neuroscientist-eliezer-masliah-papers-under-suspicion
A lot of "weird testis genes" are epigenetically silenced in somatic cells (for example, suppressed by DNA methylation), and this epigenetic control becomes defective in disease states, especially cancer. There are a whole category of "cancer/testis antigens," proteins which are usually expressed only in the testis but which are expressed in cancers like melanoma. There are currently cancer vaccine trials to target immune responses against these proteins (which might also cause male infertility but that's probably an acceptable tradeoff).
Maybe something similar is going on with LINC01609 in Alzheimer's.
Dietary vitamin A (beta carotene) is not the active form of vitamin A (retinoic acid), it needs to be converted into the active form by the body's enzymes. Once retinoic acid is formed, it can bind to the retinoic acid receptor and regulate gene expression.
Retinoid treatment bypasses these enzymes and directly activates retinoic acid receptor signaling. So, eating vitamin A in the form of beta carotene won't directly increase retinoic acid receptor signaling because the rate-limiting step is the enzymes, but retinoid treatment will. This is also why you can't overdose on vitamin A by eating carrots.
Does this meet your criteria for a good answer? If not I can explain in more detail.
Lastly, you shouldn’t use Retinoids if you’re pregnant or likely to become pregnant.
This needs more emphasis. Retinoid signaling is very important for embryonic development, so excess retinoids will really mess up your baby.
I agree with this. There's a lot of snake oil out there and cerebrolysin is just one example. I had no idea it was so popular though.
200 mg/day is a pretty high dose (at least for me)
Not just mammals, as far as I know it only works in E. coli bacteria and not in any eukaryotes.
Source:
https://www.nature.com/articles/s41586-024-07552-4
Interestingly there was just a similar article in the news section of Science, about glacier geoengineering.
https://www.science.org/content/article/avoid-sea-level-rise-some-researchers-want-build-barriers-around-world-s-most
>Mice lacking the Yap and Taz genes that control liver size have larger livers…but they also have liver cancers, and worse regeneration from liver injury.16 Similarly, mutant mice lacking Hippo signaling have unusually large livers that don’t stop growing when they hit the usual “maximal size”…but they also get lots of liver tumors not seen in wild-type mice.17
Notably, Yap and Taz are downstream mediators of Hippo signaling so these studies are looking at the same thing.