There's such a thing as gene over-expression to artificially increase the number of transcripts of a gene expressed. It's generally less easy or reliable than gene under-expression where you interfere with the expression. Doing it to get all of the affected genes back to their "healthy" levels at once would be very challenging. There's about ~30,000 genes total and at one point the study was looking at the top and bottom 5% by length of those genes so you'd be looking to over-express 1500 genes - I've never heard of a study doing anything like that but it might be possible.
On top of that, there are also feedback loops so if you put more of a certain transcript in it may induce more/less of another or get the cell to stop production of that transcript and therefore counter-act what you've done. So it would be extremely hard to get to the desired levels in all of them.
Makes sense, I wonder if it would be feasible to reduce the number of genes to be over expressed by correlation with known medical conditions e.g. cardiovascular disease, kidney disease, or other cosmetic signs of aging.
On top of that, there are also feedback loops so if you put more of a certain transcript in it may induce more/less of another or get the cell to stop production of that transcript and therefore counter-act what you've done. So it would be extremely hard to get to the desired levels in all of them.