Intermittent starvation techniques to prolong functional lifetime of liver cells in culture
The present disclosure relates to compositions and methods for culturing a population of hepatocytes in vitro, comprising co-culturing the population of hepatocytes with at least one non-parenchymal cell population and incubating the co-culture in culture medium, wherein the co-culture is periodically incubated in culture medium that does not comprise serum (serum-free culture medium).
1. A method of culturing a population of hepatocytes in vitro, comprising:
(1) seeding the population of hepatocytes in a micropattern on a culture substrate,
wherein the micropattern comprises a predetermined two-dimensional pattern of multiple microdots, the micropattern defined by a microdot diameter and a center-to-center spacing between each of any two neighboring microdots, and the microdots comprise the hepatocytes;
(2) incubating the population of hepatocytes for at least 18 hours;
(3) seeding the population of hepatocytes that has incubated for at least 18 hours with at least one non-parenchymal cell population, wherein the space between the microdots comprises the non-parenchymal cell population to achieve a co-culture;
(4) incubating the co-culture in a maintenance culture medium for a time period of about 8 days to about 6 weeks before the composition is incubated in a serum-free culture medium, wherein the maintenance culture medium comprises serum; and
(5) incubating the co-culture in a serum-free culture medium for a time period of about 2 hours to about 6 weeks, wherein the serum-free culture medium does not comprise serum,
(6) alternating steps (4) and (5) at least twice.
2. The method according to claim 1 , wherein each microdot has a diameter of about 500 μm and the center-to-center spacing between each of any two neighboring microdots is about 1200 μm.
3. The method according to claim 1 , wherein the co-culture is incubated in maintenance culture medium for at least one time period of at least 2 weeks before the composition is incubated in serum-free culture medium.
4. The method according to claim 1 , wherein the composition is incubated in serum-free culture medium for at least one time period of about 2 hours to about 3 days.
5. The method according to claim 4 , wherein the co-culture is incubated serum-free culture medium for at least one time period of about 2 days.
6. The method according to claim 1 , wherein the composition is
(a) incubated in maintenance culture medium for a time period of about 8 days, and
(b) incubated in serum-free culture medium for a time period of about 2 hours to about 3 days,
wherein (a) and (b) are alternated at least twice.
7. The method according to claim 1 , wherein said composition exhibits at least one indicator of hepatocyte function at least 4 weeks in culture.
8. The method according to claim 1 , wherein said co-culture exhibits at least one indicator of hepatocyte function at least 6 weeks in culture.
9. The method according to claim 7 , wherein said at least one indicator of hepatocyte function is selected from albumin production, urea production, ATP production, glutathione production, enzyme activity, lipid accumulation, liver gene expression, liver protein expression, or CYP2C9 activity, CYP3A4 activity, CYP1A1 activity, CYP1A2 activity, CYP2B6 activity, CYP2A6 activity, CYP2D6 activity, CYP2C8 activity, CYP2C19 activity, or CYP2E1 activity.
10. The method according to claim 1 , wherein said composition retains hepatocyte morphology at least 4 weeks in culture.
11. The method according to claim 10 , wherein said co-culture retains hepatocyte morphology at least 6 weeks in culture.
12. The method according to claim 1 , wherein the serum-free culture medium comprises glucose.
13. The method according to claim 12 , wherein the serum-free culture medium comprises glucagon.
14. The method according to claim 1 , wherein the hepatocytes are human hepatocytes.
15. The method according to claim 1 , wherein at least one of the non-parenchymal cell populations comprises non-human stromal cells selected from the group consisting of fibroblasts, fibroblast-derived cells, macrophages, endothelial cells, stellate cells, pericytes, inflammatory cells, cholangiocytes and other types of stromal cells, and combinations thereof.
16. The method according to claim 15 , wherein the stromal cells comprise 3T3-J2 murine embryonic fibroblasts.
17. The method according to claim 15 , wherein the stromal cells are growth arrested.