Rumouredrecipients of collagen, a fibrous protein which bonds tissue in thebody, include celebrities such as Liz Hurley, Kylie Minogue and Leslie Ash.The expert groups study of a range of aesthetic fillers, which areoften made from human or bovine tissue, had already found samplescontaining material from dead bodies and birds, Sir Liam added.The investigation is part of an overhaul of the cosmeti