Papers - the first editions (7)
I believe the answer is:
'papers' is the definition.
(tissue is a kind of paper)
'the first editions' is the wordplay.
'the first' becomes 't' (1st letter of 'the').
'editions' becomes 'issues' (I've seen this before).
(Other definitions for tissues that I've seen before include "Paper handkerchiefs" , "not to be sneezed at? Au contraire!" , "Soft, thin pieces of paper" , "Paper hankies" , "Thin skins or papers" .)