Dispersion of Pluripotent Stem Cells, and Pluripotent Stem Cell Product and Method for Producing Same
An object of the present invention is to provide a dispersion of pluripotent stem cells and a pluripotent stem cell product having a suitable quality as a pharmaceutical or a raw material for producing a pharmaceutical which can be stored and distributed, and a method for producing the same. The method for producing a pluripotent stem cell product of the present invention comprises (1) culturing pluripotent stem cells in an undifferentiation maintenance medium; (2) suspending the pluripotent stem cells cultured in step (1) in a first medium for suspending cells containing a ROCK inhibitor; (3) replacing the medium for suspending cells of a suspension obtained in step (2) with a medium for cryopreservation to obtain a cell dispersion solution consisting of the medium for cryopreservation and the pluripotent stem cells dispersed in the medium for cryopreservation; and (4) filling the cell dispersion solution obtained in step (3) into an airtight container so as to be in an airtight state.
1 . A method for producing a pluripotent stem cell product, comprising:
(1) culturing pluripotent stem cells in an undifferentiation maintenance medium;
(2) suspending the pluripotent stem cells cultured in step (1) in a first medium for suspending cells containing a ROCK inhibitor;
(3) replacing the medium for suspending cells of a suspension obtained in step (2) with a medium for cryopreservation to obtain a cell dispersion solution consisting of the medium for cryopreservation and the pluripotent stem cells dispersed in the medium for cryopreservation; and
(4) filling the cell dispersion solution obtained in step (3) into an airtight container so as to be in an airtight state.
2 . The method according to claim 1 , wherein step (2) further includes removing the first medium for suspending cells from a suspension obtained by suspending the pluripotent stem cells in the first medium for suspending cells containing a ROCK inhibitor, and then adding a second medium for suspending cells free of a ROCK inhibitor to suspend the pluripotent stem cells.
3 . The method according to claim 1 , wherein the ROCK inhibitor in step (2) is Y-27632.
4 . The method according to claim 3 , wherein a concentration of Y-27632 in the first medium for suspending cells in step (2) is 100 ng/mL to 100 μg/mL.
5 . A cell dispersion consisting of a dispersion medium, and pluripotent stem cells dispersed in the medium and a ROCK inhibitor, wherein the cell dispersion is contained in an airtight container.
6 . The cell dispersion according to claim 5 , wherein the ROCK inhibitor is Y-27632.
7 . The cell dispersion according to claim 6 , wherein a concentration of Y-27632 in the cell dispersion is 0.01 ng/mL to 10 ng/mL.
8 . The cell dispersion according to claim 5 , wherein the cell dispersion is in a frozen state.
9 . The cell dispersion according to claim 5 , wherein airtightness of the airtight container is airtightness satisfying a criterion requiring that bacterial proliferation be not observed in a sterility test method.
10 . The cell dispersion according to claim 9 , wherein the sterility test method is a sterility test method carried out by process simulation.
11 . The cell dispersion according to claim 5 , wherein airtightness of the airtight container is airtightness satisfying a criterion requiring that a measured value with a torque measuring device be 6.0 to 16.9 in·oz.
12 . The cell dispersion according to claim 5 , wherein a concentration of the pluripotent stem cells per unit volume of the cell dispersion is 1×10 2 cells/μL to 1×10 4 cells/μL.
13 . The cell dispersion according to claim 5 , wherein the number of the pluripotent stem cells per airtight container is 2×10 4 cells to 2×10 7 cells, and a volume of the cell dispersion per airtight container is 200 μL to 2000 μL.
14 . The cell dispersion according to claim 5 , wherein the pluripotent stem cells are human induced pluripotent stem cells (human iPS cells) or human embryonic stem cells (human ES cells).
15 . The cell dispersion according to claim 5 , wherein when the pluripotent stem cells in the cell dispersion in a frozen state are thawed, viability of the pluripotent stem cells is at least 80%.
16 . A pluripotent stem cell product consisting of an airtight container and the cell dispersion according to claim 5 contained in the airtight container.