A method including positioning a delivery device at a location in a blood vessel advancing the delivery device a distance into a wall of the blood vessel to a treatment site beyond an external elastic lamina of the blood vessel and after advancing the delivery device, introducing a treatment agent including a cellular component through the delivery device. A composition including a treatment agent comprising a cellular component associated with a matrix material, wherein the composition is suitable for percutaneous delivery. Also an apparatus suitable for delivering a treatment agent. Also, a kit including a treatment agent.
