  We analyse the mass density distribution in the centres of galaxies across
five orders of magnitude in mass range. Using high-quality spiral galaxy
rotation curves and infrared photometry from SPARC, we conduct a systematic
study of their central dark matter fraction ($f_{\rm DM}$) and their mass
density slope ($\alpha$), within their effective radius. We show that
lower-mass spiral galaxies are more dark matter dominated and have more shallow
mass density slopes when compared with more massive galaxies, which have
density profiles closer to isothermal. Low-mass ($M_{\star} \lesssim 10^{10}\,
\rm M_{\odot}$) gas-rich spirals span a wide range of \fdm\ values, but
systematically lower than in gas-poor systems of similar mass. With increasing
galaxy mass, the values of \fdm\ decrease and the density profiles steepen. In
the most massive late-type gas-poor galaxies, a possible flattening of these
trends is observed. When comparing these results to massive ($M_{\star} \gtrsim
10^{10}M_{\odot}$) elliptical galaxies from SPIDER and to dwarf ellipticals
from SMACKED, these trends result to be inverted. Hence, the values of both
$f_{\rm DM}$ and $\alpha$, as a function of $M_{\star}$, exhibit a U-shape
trend. At a fixed stellar mass, the mass density profiles in dwarf ellipticals
are steeper than in spirals. These trends can be understood by stellar feedback
from a more prolonged star formation period in spirals, causing a
transformation of the initial steep density cusp to a more shallow profile via
differential feedback efficiency by supernovae, and by galaxy mergers or AGN
feedback in higher-mass galaxies.
