If this inhibitor hypothesis were true, an experiment could be set up to determine which component/combination of components in the old-blood actually plays the

If this inhibitor hypothesis were true, an experiment could be set up to determine which component/combination of components in the old-blood actually plays the inhibitor role, with injection of separated part by component of old-blood into the young mice, more or less like a binary search. After knowing the exact combination, it would be much easier to target the inhibitor itself.