That said: ANSWER THE QUESTION.
Well first off, I do know a little about pretty much all the alopecias. To understand alopecia you can't focus on just one, you need the bigger picture.
I'm not a scientist and I don't know it all, but I thought everyone on here knew the basic difference between the 2 most common types of hair loss.
But to answer your question;
What holds the follicle back from growing hair in AA is that the immune system treats it as foreign, shocking it to fall out. This generally happens in patches, but can also go on to include complete head baldness in Totalis or even all hair on the body in Universalis. Exactly why this happens is poorly understood, but the new research surfacing might be able to answer the question.
In people with Androgenetic Alopecia the follicle in genetically suspectible individuals become increasingly sensitive to hormones in the body, which results in progressive miniaturization of the hair follicle resulting in pattern baldness. But I guess you already know that.
What separates AA from Androgenetic Alopecia is that in AA the follicle itself remains healthy as it's not affected by hormones. The hair is shocked to fall out, but can regrow at any time since the follicle itself is not compromised, but remains intact - even in individuals with complete baldness. Remission in AA is common and most people get away with a few spots that either grow back on their own or are treated with steroid injections. The disease can be in remission for years then re-appear, why is poorly understood. In people with Totalis or Universalis the prognosis can be poor, but regrowth is possible.
While AA shocks the hair to fall out and leaves completely smooth bald patches, Androgenetic Alopecia works it's demonic process on the follicle itself by shrinking it to produce poor quality hair then eventually stop. There is some evidence that the follicle remains even in Androgenetic Alopecia, but it is much smaller and unable to produce a decent hair.
As the causes of AA and Androgenetic Alopecia are totally different, the treatment for each condition will also be. It seems easier to spark a healthy follicle into growing hair, than nursing a sick and small follicle back to health.
I understand you are grasping at straws here but the truth is this is two different conditions, with different causes and outcome. If this new cure for AA is the real deal then it's probably (almost definitely) NOT gonna work on Androgenetic Alopecia.
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PGD2 suppression is still only one aspect of Androgenetic Alopecia. May not do anything for us. Given that DHT is only one of many culprits in Androgenetic Alopecia and balding continues while blocking it completely, it only proves that there's much more to Androgenetic Alopecia than a single pathway. So... PGD2 may exhibit similar problems. Personally, I don't think addressing PGD2 is going to cut it. Probably some reversal and a more guaranteed halt to hair loss, but not a complete solution like arthritis drugs for AA. Something much bigger than PGD2 and DHT imo needs to be addressed... if not, then all pathways simultaneously.
This. We can agree on. I think you are right! I feel like we are missing the golden egg here, but it probably comes down to multiple processes happening at once to result in Androgenetic Alopecia. I do worry though, if blocking all those "pathways" simultaneously, what effect that will have on the body. Because whatever is in our bodies naturally are there for a reason, and completele blockage might be dangerous for other parts of our body. I think Androgenetic Alopecia simply comes down to how some people's bodies are genetically programmed to react a certain way to certain hormones etc, which is why some people have Androgenetic Alopecia and some lucky bastards don't.