The electric manipulation of magnetic textures in nanostructures,important for applications in spintronics,can be realized through the spin-transfer torque mechanism: a spin-polarized current can modify the magnetization of skyrmions and magnetic vortices,and eventually change the topology of the magnetization.The spin-transfer torque and the intrinsic space and time scales of the topological changes are essentially quantum mechanical.We model the interaction between itinerant and fixed spins with a simple tight-binding hamiltonian in a square lattice.The dynamics is described by the Schr(o)dinger equation for the electrons and the Landau-Lifshitz equation for the evolution of the magnetic texture.We investigate the phenomenology of the topological change of a Belavin-Polyakov skyrmion under the action of a spin-polarized current and show that adding an exchange dissipation term,regularizes the transition towards a ferromagnetic state.