UCN2 and Dilatation of the cerebral artery: Several other studies have also found that factors which reduce VSMC proliferation result in increased aneurysm severity, for example, Emeto et al. suggest that an anti-proliferative factor, urocortin-2, is associated with AAA20, or Luo et al., who found that aberrant expression of microRNA-9 increases intracranial aneurysm development by reducing proliferation21.