Method for treating subjects suffering from chronic ulcers

A method of regenerating tissue at a chronic tissue ulcer site of a subject in need thereof, comprising:

• i) aseptically implanting into the chronic tissue ulcer site a multilayer sheet of collagen material in dry state comprising (a) a barrier layer of collagen material having a smooth face and a rough fibrous face opposite said smooth face and (b) a spongeous matrix layer of collagen material connected to said rough fibrous face, said spongeous matrix layer of collagen material having an open sponge-like texture, such that said rough fibrous face of said barrier layer of collagen material to which is connected said spongeous matrix layer of collagen material having an open sponge-like texture faces toward and is adjacent to the chronic tissue ulcer;
• and
• ii) hydrating the multilayer sheet of collagen material in dry state using blood, an isotonic solution or a combination thereof.

A method of binding and preserving a subject's growth own factors in a chronic tissue ulcer site of a subject in need thereof, comprising:

• i) aseptically implanting into the chronic tissue ulcer site of the subject a multilayer sheet of collagen material in dry state comprising (a) a barrier layer of collagen material having a smooth face and a rough fibrous face opposite said smooth face and (b) a spongeous matrix layer of collagen material connected to said rough fibrous face, said spongeous matrix layer of collagen material having an open sponge-like texture, such that said rough fibrous face of said barrier layer of collagen material to which is connected said spongeous matrix layer of collagen material having an open sponge-like texture faces toward and is adjacent to the chronic tissue ulcer site;
• and
• ii) hydrating the implanted multilayer sheet of collagen material using blood, an isotonic solution or a combination thereof, thereby promoting binding of said subject's own growth factors with the multilayer sheet of collagen material and preservation of said subject's own growth factors and growth factor activity in the chronic tissue ulcer site thereby inducing expression of one or more growth factor-responsive genes in one or more human cell types in the chronic tissue ulcer site of the subject.