In recent years, the use of stem cells has generated increasing interest in regenerative medicine
and cancer therapies. The most potent stem cells derive from the inner cell mass during embryonic
development and their use yields serious ethical and methodological problems. Recently, a number
of reports suggests that another suitable source of multipotent stem cells may be the amniotic fluid.
Amniotic fluid mesenchymal stem cells (AFMSCs) are capable of extensive self-renewal, able to
differentiate in specialized cells representative of all three germ layers, do not show ethical restriction,
and display minimal risks of teratomas and a very low immunogenity. For all these reasons, amniotic
fluid appears as a promising alternative source for stem cell therapy. Their recent discovery implies a lack
of knowledge of their specific features as well as the existence of a protocol universally recognized as the
most suitable for their isolation, growth and long-term conservation. In this study, we isolated stem cells
from six amniotic fluids; these cells were cultured with three different culture mediums [Mesenchymal
Stem Cell Medium (MSCGM), PC-I and RPMI-1640], characterized by cytofluorimetric analysis, and
then either frozen or induced to neuronal differentiation. Even if the immunophenotype seemed not to
be influenced by culture medium (all six samples cultured in the above-mentioned mediums expressed
surface antigens commonly found on stem cells), cells showed different abilities to differentiate into
neuron-like cells and to re-start the culture after short\long-term storage. Cells isolated and cultured
in MSCGM showed the highest proliferation rate, and formed neuron-like cells when sub-plated with
neuronal differentiation medium. Cells from PC-I, on the contrary, displayed an increased ability to restart
culture after short\long term storage. Finally, cells from RPMI-1640, even if expressing stem cells
markers, were not able to differentiate in neuron-like cells. Further studies are still needed in order to
assess the effective role of culture medium for a successful isolation, growth, differentiation and storage
of AFMSCs, but our data underline the importance of finding a universally accepted protocol for the
use of these cells.