Table 1.

Number of NSCs in Subsequent Cultures of MSC-Derived NSCs

Passage	1st	2nd	3rd	4th	5th
Donor
1	102.8 ± 11.5 (20.4)	99.2 ± 9.4 (19.8)	101.6 ± 13.3 (20.2)	104.5 ± 13.3 (20.8)	99.6 ± 9.8 (19.9)
2	101.4 ± 10.3	101.6 ± 11.2	99.6 ± 11.6	99.2 ± 11.6	101.2 ± 11.8
3	103.4 ± 12.5	102.1 ± 11.3	104.2 ± 13.9	99.4 ± 10.8	101.6 ± 11.6

Abbreviations: MSC, mesenchymal stem cell; NSC, neural stem cell.

Cells were plated in 96-well plates as 500 cells/200 μL per well for each passage. These wells were scored 7 days later for the presence of spheres. The total number of wells analyzed for each passage is 60. The number of spheres per well is presented as the mean ± SD in each passage. The numbers in parenthesis represent the frequency of NSCs.

These data are compiled from three independent experiments using MSCs derived from different donor samples. Each neurosphere averages 200 cells, so each well contains an average of 20,000 cells (100 neurospheres × 200 cells/ neurosphere). Since the percentage for neurosphere-forming cells in each passage remains constant (averaging 20%), the estimate for the magnitude of expansion in each passage is 40-fold (20,000 cells/500 cells).