GDNF and Alzheimer disease: In agreement with these findings, in a previous report we observed that the preconditioning of human AD-MSC, with 400 μM of the iron chelator DFX for 48 h, increased HIF-1α levels and upregulated the mRNA levels of pro-angiogenic factors such as VEGFα and angiopoietin 1, also increasing the expression of potent neuroprotective factors including nerve growth factor (NGF), glial cell-derived neurotrophic factor (GDNF), neurotrophin-3 (NT-3), cytokines with anti-inflammatory activity, such as IL-4 and IL-5, and antiapoptotic factors [53].