I'm not sure why the most cited article couldn't be called a follow-up or at least summary of intention to follow-up.

"A comprehensive concept that connects NAD+ metabolism to the control of aging and longevity in mammals has been proposed, and the stage is now set to test whether these exciting preclinical results can be translated to improve human health."

https://www.sciencedirect.com/science/article/pii/S155041311...