Method for producing modified mesenchymal stromal stem cells with improved properties, modified cells obtained by this method, composition including such cells

A method for the modification of mesenchymal stromal stem cells comprising the following phases:

• a) seeding said cells on a plastic support in the presence of an appropriate growth-medium promoting their expansion;
• b) adding at least one medium additive rich in human-derived platelet growth factors aimed to promote the expansion of said cells;
• c) detaching said expanded cells from the plastic surface;
• d) adding to said expanded cells a gene construct in order to obtain a mixture;
• characterized in that said method also comprises the following phases:
• e) submitting said mixture to one or more electrical pulses to electroporate said mixture;
• f) suspending said electroporated mixture having been submitted to one or more electrical pulses in said growth-medium comprising the additive rich in human-derived platelet growth factors, and transferring the resulting mixture into a suitable container for incubation;
• g) resuspending said cell mixture adding an amount of growth-medium containing a percentage of additive rich in human-derived platelet growth factors higher than the same growth-medium used in the previous phase (b);
• h) transferring the modified cells to a plastic support for cell culture and incubating;
• i) at the end of the incubation, adding to said support a volume of growth-medium devoid of said additive rich in human-derived platelet growth factors to restore the equivalent additive concentration applied in the growth-medium used in said phase (b) for cell expansion.