(A) Representative micrographs of immunofluorescent staining for neuron-derived neurotrophic factor (NDNF) (red) with nuclei stained blue with 4′,6-diamidino-2-phenylindole (DAPI). NDNF messenger ribonucleic acid (mRNA) and protein expression were significantly decreased in old human bone marrow multipotent mesenchymal stromal cells (hBM-MSCs) compared with infant and young hBM-MSCs as measured by (B) reverse transcription polymerase chain reaction and (C) Western blot, respectively. (D) The NDNF protein level negatively correlated with age. The list of X (age) and Y (NDNF protein level) was analyzed using a correlation regression analysis. n = 8 to 13/group. ACTB = beta-actin.