Abstract: The present invention relates to the use of a gene transfer product to reduce hyperplastic connective tissue growth after tissue trauma or implantation of a medical device. The present invention also relates to a medical device with improved biological properties for an at least partial contact with blood, bodily fluids and/or tissues when introduced in a mammalian body, which device comprises a core and a nucleic acid, encoding a product capable of leading to production of extracellular superoxide dismutase present in a biologically compatible medium. Said nucleic acid encodes a translation or transcription product, which is capable of inhibiting hyperplastic connective tissue growth and promoting endothelialisation in vivo at least partially on a synthetic surface of said core. The present invention also relates to a method of producing a medical device according to the invention.