Methods for increasing isolation yields of cellular products
Methods of isolating cellular products, such as pancreatic islets, may be used in diabetes research and therapeutic transplantation. The methods may involve providing a donor tissue having desired cells and undesired cells, perfusing the donor tissue with a perfusion solution, developing edema during perfusion of the donor tissue to form a swelled tissue, and separating the desired cells from undesired cellular material to obtain a cellular product. The methods may also include disrupting the tissue, and separating the desired cells from undesired cellular material to obtain the cellular product. The methods may result in an increased yield of cellular product that retains sufficient functional integrity to be useful as a transplantation resource.
1. A method of isolating a cellular product, comprising:
providing a donor tissue having desired cells and undesired cells;
connecting a perfusion apparatus to the donor tissue to allow fluid communication between the donor tissue and the perfusion apparatus;
performing hypothermic machine perfusion by perfusing the donor tissue with a perfusion solution under hypothermic conditions, wherein an O 2 content in the perfusion solution is replenished during the perfusion, and the perfusion solution is a hypothermic blood substitute, comprising one or more members selected from the group consisting of cytoprotective agents and perfluorochemicals;
developing edema during perfusion of the donor tissue to form a swelled tissue via increasing a first perfusion pressure applied by the perfusion apparatus to the tissue to achieve a second perfusion pressure, where the second perfusion pressure is in a range of from about 20 mmHg to about 50 mm Hg;
treating the swelled tissue with a digestive enzyme;
monitoring the extracellular space in the donor tissue by microdialysis; and
separating the desired cells from undesired cellular material to obtain a cellular product; wherein the tissue is a pancreas, the oxygen consumption rate of the donor tissue is assessed before the perfusion apparatus is connected to the donor tissue and the oxygen consumption rate of the donor tissue is assessed and monitored after the perfusion apparatus is connected to the donor tissue, and an O 2 demand of the donor tissue is satisfied throughout a preservation interval/process occurring from the time the perfusion apparatus is connected to the donor tissue to a time when the perfusion apparatus is disconnected from the donor tissue.
2. The method of claim 1 , further comprising:
monitoring buoyancy of the donor tissue to assess the extent of edema;
monitoring surface area of the donor tissue to assess the extent of edema;
monitoring a circumference of the donor tissue to assess the extent of edema;
monitoring mass of the donor tissue to assess the extent of edema; and/or
monitoring volume of the donor tissue to assess the extent of edema.
3. The method of claim 1 , wherein the swelled tissue has a mass that is at least 110% of an initial non-perfused mass of the donor tissue, and/or the swelled tissue has a volume that is at least 110% of an initial non-perfused volume of the donor tissue.
4. The method of claim 3 , wherein the mass of the swelled tissue is from about 150% to about 250% of the mass of the donor tissue, and/or the volume of the swelled tissue is from about 150% to about 250% of the volume of the donor tissue.
5. The method of claim 1 , wherein the swelled tissue has a mass that is less than 300% of an initial non-perfused mass of the donor tissue, and/or the swelled tissue has a volume that is less than 300% of an initial non-perfused volume of the donor tissue.
6. The method of claim 1 , further comprising slicing the pancreas.
7. The method of claim 1 , wherein the tissue is pancreatic tissue and the cellular product comprises pancreatic islets.
8. The method of claim 1 , further comprising introducing cytoprotective agents during perfusion of the donor tissue for preventing cold-induced cell death of the donor tissue.
9. The method of claim 1 , further comprising introducing cytoprotective agents during perfusion of the donor tissue for preventing cells of a donor pancreas from entering destructive pathways.
10. The method of claim 1 , further comprising introducing cytoprotective agents during perfusion of the donor tissue for inhibiting mitochondrial dysfunction in cells of a donor pancreas.
11. The method of claim 1 , further comprising preventing anaerobic glycolysis in the donor tissue.
12. The method of claim 11 , wherein preventing anaerobic glycolysis in the donor tissue comprises introducing perfluorochemicals into the perfusion solution.
13. The method of claim 1 , further comprising preventing oxygen deprivation/depletion in the donor tissue.
14. The method of claim 13 , wherein preventing oxygen deprivation/depletion in the donor tissue comprises introducing perfluorochemicals into the perfusion solution.
15. The method of claim 1 , further comprising disconnecting the perfusion apparatus from the donor tissue.
16. The method of claim 1 , further comprising replenishing O 2 content in the perfusion solution during perfusion.
17. The method of claim 1 , wherein the donor tissue is from a heart-beating donor.
18. The method of claim 1 , wherein the donor tissue is from a non-heart-beating donor.
19. The method of claim 1 , wherein monitoring the extracellular space in the donor tissue by microdialysis comprises implanting a dialysis probe into the donor tissue and assessing the concentration of interstitial fluid components.
20. The method of claim 19 , wherein the concentration of interstitial fluid components is assessed periodically.
21. The method of claim 19 , wherein the interstitial fluid components are selected from the group consisting of glucose, lactate, pyruvate, glycerol, ATP, O 2 and CO 2 .
22. The method of claim 1 , wherein the donor tissue is from a mammal.
23. The method of claim 22 , wherein the mammal is a human.
24. The method of claim 22 , wherein the mammal is a pig.
25. The method of claim 1 , wherein the hypothermic machine perfusion is performed with a perfusion solution that is at a temperature of 5-7° C.
26. The method of claim 19 , wherein the dialysis probe comprises a semi-permeable bio-compatible membrane as an active part.
27. A method of isolating a cellular product, comprising:
providing a donor tissue having desired cells and undesired cells;
connecting a perfusion apparatus to the donor tissue to allow fluid communication between the donor tissue and the perfusion apparatus;
performing hypothermic machine perfusion by perfusing the donor tissue with a perfusion solution under hypothermic conditions, wherein
an O 2 content in the perfusion solution is replenished during the perfusion,
ATP levels in the donor tissue is increased during perfusion, and
the perfusion solution is a hypothermic blood substitute, comprising: cytoprotective agents and perfluorochemicals;
developing edema during perfusion of the donor tissue to form a swelled tissue, wherein developing edema during perfusion of the donor tissue comprises:
increasing a first flow rate of the perfusion solution through the tissue to achieve a second flow rate, where the second flow rate is in the range of from about 20 ml/min to about 30 ml/min;
treating the swelled tissue with a digestive enzyme;
monitoring the extracellular space in the donor tissue by microdialysis; and
separating the desired cells from undesired cellular material to obtain a cellular product; wherein
the tissue is a pancreas,
the oxygen consumption rate of the donor tissue is assessed before the perfusion apparatus is connected to the donor tissue and the oxygen consumption rate of the donor tissue is assessed and monitored after the perfusion apparatus is connected to the donor tissue, and
an O 2 demand of the donor tissue is satisfied throughout a preservation interval/process occurring from the time the perfusion apparatus is connected to the donor tissue to a time when the perfusion apparatus is disconnected from the donor tissue.