  We analytically work out the long-term orbital perturbations induced by the
first term of the expansion of the perturbing potential arising from the local
modification of the Newton's inverse square law due to a topology R^2 x S^1
with a compactified dimension of radius R recently proposed by Floratos and
Leontaris. We neither restrict to any specific spatial direction for the
asymmetry axis nor to particular orbital configurations of the test particle.
Thus, our results are quite general. Non-vanishing long-term variations occur
for all the usual osculating Keplerian orbital elements, apart from the
semimajor axis which is left unaffected. By using recent improvements in the
determination of the orbital motion of Saturn from Cassini data, we
preliminarily inferred R >= 4-6 kau. As a complementary approach, the putative
topological effects should be explicitly modeled and solved-for with a modified
version of the ephemerides dynamical models with which the same data sets
should be reprocessed.
