Use of hematopoietic growth factors (I), especially erythropoietin (EPO), thrombopoietin (TPO) or their derivatives, analogs and fragments, to prepare a composition for structural regeneration of tissue, is new. Independent claims are also included for the following: (1) similar use of an EPO-inducing factor (II)； (2) carrier structure containing at least one (I) or (II)； (3) preparing the structure of (2)； and (4) composition comprising cells (A) that have been pretreated, in vitro, with (I). ACTIVITY : Hepatotropic； Osteopathic； Cardiant； Ophthalmological； Uropathic； Antiinflammatory； Antiulcer； Vulnerary； Neuroprotective. Part of the liver was removed from pigs, then the animals (a) given no treatment； (b) treated locally with 10 4>； units EPO and a fibrin glue； or (c) treated systemically with 10 4>； units EPO on days 0, 3, 7 and 11. After 14 days, the mean liver volume (ml) was (a) 892； (b) 894 and (c) 1073, and liver weight (g) was (a) 1001； (b) 1027 and (c) 1249； where these results for (c) are statistically significant at p less than 0.05. MECHANISM OF ACTION : Promoting regrowth of tissue.
