EP1880003A1

EP1880003A1 - Expansion medium for the in vitro cultivation of stem cells method for the multiplication of stem cells in vitro and use of the stem cells multiplied by said method

Info

Publication number: EP1880003A1
Application number: EP06742280A
Authority: EP
Inventors: Markus Tonak; Wiltrud Richter; Julia Vogel; Philip Kasten
Original assignee: Stiftung Orthopadische Universitatsklinik
Current assignee: Stiftung Orthopadische Universitatsklinik
Priority date: 2005-05-09
Filing date: 2006-04-26
Publication date: 2008-01-23
Also published as: WO2006119727A1; DE102005022032A1

Abstract

The invention relates to an expansion medium for the in vitro cultivation of stem cells in a composition, comprising all necessary components for stem cell growth with exclusion of xenogenic additives, characterised in that the composition contains platelet-rich plasma (PRP) and at least one growth factor.

Description

EXPANSION MEDIUM FOR IN VITRO CULTURING STEM CELLS,

METHOD FOR THE REPRODUCTION OF STEM CELLS IN VITRO AND USE OF THE STEM CELLS MADE UPON THE PROCEDURE

The present invention relates to an expansion medium for in vitro cultivation of stem cells in a composition comprising all the components required for growth of the stem cells, excluding xenogenic additives, and a method of propagating stem cells in vitro, and to the use of the stem cells propagated by the method for transplantation or reimplantation into a recipient organism.

Until now, in vitro cultivation of adult stem cells, such as mesenchymal stem cells (MSCs) from a donor's bone marrow aspirate, has proven to be very challenging and difficult. This is due to the fact that the pluripotent cells at the time of collection are subject to a natural aging process, whereby the cells in addition to their ability to divide lose their pluripotent character, ie their pluripotency. Controlled differentiation of stem cells, e.g. in bones or cartilage, is no longer possible at this time at the latest. Therefore, expansion of mesenchymal stem cells in the known culture media is possible only for a very short period of time, namely, until the time of culture when the cells lose their pluripotent character. This period is to a considerable degree dependent on the origin of the stem cells, i.e. that stem cells of different donors can be cultured for different periods before they lose their pluripotency. In addition, so far no media are known without xenogenic additives, ie media with purely allogenic or autogenous additives in which the stem cells can be expanded quickly and in a sufficiently large number for each application.

In general, the MSCs are obtained from the bone marrow aspirate of a donor organism which, for example, is from the iliac crest, sternum, or occasionally from the long bones, if opened in the course of surgery. After removal of the bone marrow aspirate, follow Purification and selection steps to isolate the MSC. The purified and isolated MSC are then contains, in a culture medium containing xenogeneic additives, under suitable standard culture conditions, usually with 6% CO ₂ air saturation at 37 ⁰ C and 98% humidity in an incubator in bottles, Petri dishes or other culture containers up to one for the planned clinical application expands sufficient cell count. A xenogenic additive found in the expansion media used by many research groups is, for example, a fetal bovine serum (FCS).

As an objective of a clinical application, in the field of reconstructive medicine, the improvement of bone healing and bone production using the expanded mesenchymal stem cells in combination with a suitable carrier material (e.g., a ceramic) is considered.

Frequently, however, these clinical applications fail even in their beginnings, since a sufficiently large number of stem cells, which is needed, for example, to cure a bone or cartilage defect of a recipient organism, can not be achieved, and because the cells due to the aging process described in Course of cultivation lose their ability to divide (pluripotency) and differentiate. For example, for a bone defect of 1.5 cm in length and 4 mm in diameter, a number of 10 ⁶ MSC is necessary to achieve satisfactory healing of the bone. An expansion with a cell count of more than 10 ⁶ MSC from the bone marrow aspirate of a donor organism but with the known culture media almost or not possible (varies depending on the general condition and age of the donor) or takes too long a period to clinical application.

Nevertheless, in order to obtain a sufficient number of MSC in a very short time, the approach is followed which provides for repeated isolation of MSC from successively withdrawn bone marrow aspirates of the same donor in order to mix the cells thus obtained. A disadvantage is that the donor is repeatedly subjected to a bone marrow puncture, which is a painful and stressful procedure. Another approach for obtaining a sufficient number of MSCs is the mixing ("pooling") of MSCs from different donors, a problem that arises from the fact that the recipient organism not only owns (as in the case of a reimplantation or autologous transplant) but also transplantation (allograft), which may lead to infections or immunological reactions in the recipient organism, as a result of which a healing process of the bone or cartilage defect to be treated is worsened or even in the case of an immunological reaction of the recipient organism to the alien MSC the transplanted tissue is repelled, healing of the bone or cartilage defect to be treated is thereby prevented and, overall, the overall condition of the recipient deteriorates.

Yet another approach is by using suboptimal cell counts for the application. The disadvantage here is that the success of a defect healing of the bone or cartilage is endangered by the too low density of the transplanted stem cells.

Another disadvantage of culturing MSC in expansion media with xenogenic additives, such as bovine serum products, is the risk of contamination with prions that can infect the MSC and be delivered to the recipient organism at transplantation. In this respect, the transplantation of stem cells that have been expanded in a medium containing bovine serum products, under a significant health hazard, namely with the risk that the recipient of mad cow disease (BSE) takes place. In addition, immunological reactions of human recipients to bovine serum products have become known.

The present invention is based on the object, an expansion medium and a method for rapid propagation of stem cells in vitro in a sufficient number for clinical applications, excluding infections or immunological reactions of the recipient organism, which are caused by xenogeneic components, and the use of the increased To provide stem cells for clinical applications. According to the invention the above object is achieved with respect to the expansion medium by a composition for an expansion medium having the features of claim 1. Thereafter, the composition of the aforementioned type is designed such that the composition contains platelet-rich plasma (PRP) and at least one growth factor.

Furthermore, the above object is to provide a method for rapidly increasing stem cells in vitro in a sufficient number for clinical applications, excluding infections or immunological reactions of the recipient organism caused by xenogeneic components, by a method having the features of the claim 10 solved. Thereafter, a method for propagating stem cells in vitro of the type mentioned is designed such that the stem cells are propagated in an expansion medium without xenogeneic additives containing the components required for the growth of stem cells, platelet-rich plasma (PRP) and at least one growth factor.

Finally, the above object regarding the use of the MSC is solved by the features of claim 18. Thereafter, a use of the propagated by the claimed method stem cells for transplantation or reimplantation in a recipient organism is provided.

In accordance with the invention, it has been recognized that the addition of PRP, for example, in place of fetal bovine serum (FCS), can provide an expansion medium for expansion of human stem cells. In other words, this completely eliminates the risk of the recipient following transplantation or reimplantation of the expanded stem cells into BSE. In addition, the use of the PRP can effectively prevent immunological reactions or human recipient infections to xenogenic additives in the medium, such as reactions to bovine serum products. In addition, it has been recognized in accordance with the invention that expansion of the stem cells can be accelerated by the addition of growth factors. In addition, in inventive it has been recognized that the stem cells propagated by the method according to the invention in the expansion medium according to the invention can be used for transplantation and / or reimplantation into a recipient organism.

Thus, an expansion medium and method for rapidly proliferating stem cells in vitro in a sufficient number for clinical applications, excluding infection or immunological reactions of the recipient organism caused by xenogeneic components, as well as the use of the increased stem cells for clinical applications is realized. ^~

Preferably, the expansion medium composition for in vitro cultivation of stem cells may contain platelet-rich plasma (PRP) having a 0.5 to 2.5-fold increased concentration of platelets compared to whole blood. More preferably, the PRP has a 2.5 to 4.5-fold increased concentration of platelets compared to whole blood, and most preferably, the PRP has a 3 to 6.5-fold increased concentration of platelets compared to whole blood. However, it is also conceivable that the PRP can be enriched so much that a concentration of platelets of more than 6.5 times in comparison to whole blood can be achieved. In a particularly advantageous manner, the enriched PRP can be used in a final concentration of 0.5 to 10% (v / v) in the expansion medium for culturing the stem cells. Depending on the type and nature of the stem cells, however, a final concentration of the PRP in the expansion medium of more than 10% (v / v) can also be used.

In order to be able to provide an expansion medium specially adapted to the recipient organism for in vitro cultivation of the stem cells which does not contain any xenogenic additives, the PRP has its origin in the type of the recipient. Concretely, the PRP has a human origin ("allogeneic transplantation") for the expansion of human stem cells. "Avoiding immunological reactions to foreign platelet-rich plasma of the same species is achievable by using the recipient's own plasma to propagate their own stem cells (" autologous Transplantation"). As additional ingredients, the composition for the expansion medium contains at least two different growth factors. A platelet-dependent growth factor (PDGF) with an epidermal growth factor (EGF) proves to be particularly advantageous in combination with the PRP in order to achieve rapid expansion of the stem cells, in particular of mesenchymal stem cells. In view of the problem of infection mentioned and the avoidance of the immunological reaction of the recipient organism to xenogenic additives, recombinant human growth factors such as, for example, rh EGF and rh PDGF are preferred for multiplying human mesenchymal stem cells. The composition preferably contains this in combination with the recombinant human Growth factor rh EGF the recombinant human growth factor rh PDGF-AA, more preferably the recombinant human growth factor rh PDFG-AB, and most preferably the recombinant human growth factor rh PDGF-BB. A final concentration in the expansion medium of the respective growth factors of 2 to 5 ng / ml is considered to be preferred. More preferably, the final concentration is from 6 to 8 ng / ml, and most preferably, the expansion medium has a final concentration of the respective growth factors of 8 to 10 ng / ml. Depending on the type of stem cells and the time available (up to clinical application) for proliferation of stem cells, final concentrations of the respective growth factors of more than 10 ng / ml can also be used in the expansion medium, in particular for rapid expansion of the cells in the shortest possible time , It is conceivable that when using different growth factors, these are added to the medium in a ratio of 1: 1 or in a ratio that is not equal to 1: 1 in order to be able to control the expansion time and the expansion of the stem cells in a targeted manner.

Particularly advantageous for the growth of stem cells, in particular of human mesenchymal stem cells, proves to be a composition containing the following components per one liter of medium in the stated amount or final concentration: Component UJVlfidJium EodkojQzanJratLoii

Fertigkulturmeclium with high

Glucose content (eg Dulbecco ^' s Modified

Eagle Medium (D-MEM) (1x) liquid (high

Glucose) (Invitrogen)) 567.5 ml

Finished culture medium with addition of

Trace elements (e.g., MCDB 201 (Sigma)) 400 ml

Supplement 20 ml

- human insulin 10 mg

- human transferrin 10 mg

- Sodium selenite 10 μg penicillin / streptomycin 10 ml 1% (v / v)

Dexamethasone (20 μg / ml in 1 ml of ethanol and 45 ml of H ₂ O) 400 μl 0.02 μM

Ascorbic acid 2-phosphate 1, 5 mg 580 ul 0.1 mM

PRP (3 to 6.5-fold increased concentration) (fresh) 30 ml 3% (v / v)

EGF (fresh) 250 μl 10 ng / ml rh PDGF-BB, rh PDGF-AA or rh PDGF-AB (fresh) 250 μl 10 ng / ml,

wherein the medium components can be sterile-filtered at -2O ⁰ C store for up to 8 weeks and the PRP and the growth factors are added fresh to the medium components. Particularly advantageous is the standing and cooling of the medium and the subsequent processing of the medium, for example the pipetting up or down or stirring the medium, on the ability to divide the stem cells, since by letting at cooling temperatures, the platelets in the medium clumping and By processing the medium, the PRP forms "clots" that have a positive effect on the ability of the stem cells to divide.

Advantageously, a cultivation of the stem cells over a long period of time, namely up to 8 weeks, with the expansion medium in the above-mentioned composition and / or a rapid expansion of the stem cells, in particular the human mesenchymal stem cells within a period of a few weeks (2 bis 3 weeks). It is advantageous that the cells do not differentiate into bone, cartilage, fat or tendon cells and beyond that, retain their ability to divide. This makes it possible to expand primary mesenchymal stem cells from the bone marrow aspirate of a donor to a number of more than 10 ⁶ cells (up to more than 10 ⁸ cells). It is advantageous that repeated bone marrow aspiration on a donor is superfluous and that bone marrow aspirate can be used by almost any donor, regardless of age or health.

Regarding the claimed method, to avoid repetition, reference is made to the statements and the advantages of the claimed expansion medium for the in vitro cultivation of stem cells.

In a particularly advantageous manner, the stem cells which have been propagated in said expansion medium by the said process can be used for transplantation or reimplantation into a recipient organism. For example, expanded stem cells derived from a donor different from the recipient but of the same species may be used for allogeneic transplantation. Preferably, endogenous stem cells of the recipient, such as mesenchymal stem cells for reimplantation or autologous transplantation, are used to treat and cure a bone or cartilage defect of the recipient. More specifically, at the time of reimplantation, the donor of the bone marrow and the MSC expanded therefrom and the recipient of the expanded MSC are the same person, thus precluding an immunological response to exogenous antigens.

In the case of transplantation or reimplantation, in particular in the treatment of larger bone or cartilage defects, the use of a carrier material to which and / or into which the cells settle during the cultivation proves to be particularly advantageous. For example, mesenchymal stem cells of a primary culture of a donor can be used in conjunction with the carrier material for the treatment and healing of bone defects having a size of 0.5 cm to 10 cm and 0.5 cm to 5 cm in diameter. In this case, preferably hydroxyapatite (HA), a dimineralized bone matrix (DBM), a polyactide matrix or polyglycol matrix is used as the carrier material, in particular in the field of tissue engineering As support material, a β-tricalcium phosphate (β-TCP) and most preferably calcium-deficient hydroxyapatite (CDHA) is used. However, other support materials, such as a collagen matrix, a gelatin matrix, a chitosan matrix or decellularized tissue, such as mucosa, or combinations of the materials enumerated hereinabove are also useful.

Moreover, it is also conceivable that the increased root lines according to said method for the regeneration, treatment and healing of tissue defects other than the bone or cartilage defects are used. For example, connective tissue, nerve, vascular or tendon defects could be treated and regenerated. However, it is also conceivable that in the case of skin defects caused by burns, infections, diseases and / or abrasions, stem cells which are the progenitor cells of the skin are propagated and used. Suitable carrier materials are, for example, absorbable materials which can be applied to the body parts with the ingrown cells as a "second" skin.

There are now various possibilities for designing and developing the teaching of the present invention in an advantageous manner. On the one hand, reference should be made to the subordinate claims, on the other hand to the following explanation of a preferred example. In connection with the explanation of the preferred example, generally preferred embodiments and further developments of the teaching will be explained without restricting the teaching thereto.

example

Human mesenchymal cells were obtained from the bone marrow aspirate, which was removed from the iliac crest of a donor by bone marrow puncture. The bone marrow aspirate was purified and selected, and the secreted mesenchymal stem cells in an expansion medium (see below) under standard culture conditions (6% CO ₂ , 37 ⁰ C and 98% humidity) increased. One liter of expansion medium was prepared as follows: 567.5 ml each Dulbecco ^'s Modified Eagle Liquid Medium (D-MEM) (1x) (high giucose) (Invitrogen, Cat # 41966), 400 ml MCDB 201 (Sigma, Cat # l-1884), 20 ml supplement ([10 mg / l final conc .] human insulin (Sigma, Cat # l-9278), [10 mg / l final conc.] human transferrin, Cat # T-8158) and [10 μg / l final conc.] sodium selenite (Sigma, Cat # S-9133)) , 10 ml [1% final conc.] Penicillin / streptomycin (Biochrom AG, Cat # A-2213), 400 μl [0.02 μM final conc.] Dexamethasone (Sigma, Cat # D-8893) 20 μg / ml in 1 ml Ethanol to dissolve in 45 ml of sterile MiIIi-QH ₂ O) and 580 μl [0.1 mM final conc.] Ascorbic acid 2-phosphate 1.5 mg (Sigma, Cat # A-8960) were combined and sterile filtered. The solution thus prepared was at -2O ⁰ C to max. Frozen for 8 weeks. To prepare the fresh medium, the required amount of medium was thawed and 30 ml [3% final conc.] Concentrated fresh PRP (3 to 6.5-fold concentration of thrombocytes compared to whole blood) and 250 .mu.l [10 ng / ml final conc. Growth factor rh EGF and 250 μl [10 ng / ml final conc.] Rh PDGF-BB (Strathmann Biotec hEGF-500 and hPDGF-BB-10, respectively) were added and no longer sterile-filtered. After that, the standing of the medium followed for at least 2 hours at -4 ⁰ C to allow the platelets clumped. After standing, the medium was made ready for use by pipetting up and down to form a "clot".

The ready-to-use fresh PRP expansion medium without xenogenic additives was compared to a conventional expansion medium with xenogeneic addition of FCS (fetal bovine serum) for the rate of proliferation of media-cultured human mesenchymal stem cells. A proliferation rate of the MSC in the PRP expansion medium was measured which was significantly higher than the proliferation rate of the MSC in the FCS expansion medium (p <0.05).

The use of the PRP expansion medium without xenogenic additives for the expansion of mesenchymal stem cells has been used in the animal model for so-called "tissue engineering", namely in conjunction with excipients, for example in conjunction with a dimineralized bone matrix (DBM), a β-tricalcium phosphate (β-TCP) and a calcium-deficient hydroxyapatite (CDHA) ceramic body of 84% porosity with an average pore diameter in the macroscopic range of 0.2 to 0.6 mm (55 vol%) and a pore diameter in the microscopic range of <5 μm and a specific surface tested on average 0.5 m ² / g. Ectopic bone formation was seen after 8 weeks in 4 of 16 MSC treated ceramic CDHA bodies and in 2 of 16 treated β-TCP ceramic bodies in immunodeficient mice.

In addition to the ability of the MSC medium to expand faster and more reliably than the known media, the ability of the MSC produced in the PRP expansion medium to evolve bone in vivo has also been demonstrated. In addition, it could be shown that the MSC retain their desired properties to differentiate into bone and cartilage. In addition, it was found that the desired surface markers of the cells are retained in the expansion process.

Finally, it should be expressly understood that the example described above merely serves to discuss the claimed teaching, but does not limit it to the example.

Claims

claims

An expansion medium for in vitro cultivation of stem cells in a composition comprising all the components required for growth of the stem cells, excluding xenogenic additives, characterized in that the composition contains platelet-rich plasma (PRP) and at least one growth factor.

2. Expansion medium according to claim 1, characterized in that the PRP has a 3 to 6.5-fold increased concentration of thrombocytes compared to whole blood.

3. Expansion medium according to claim 1 or 2, characterized in that the composition contains human PRP.

4. Expansion medium according to one of claims 1 to 3, characterized in that the composition contains at least two different growth factors.

5. Expansion medium according to one of claims 1 to 4, characterized in that the composition contains recombinant human growth factors.

6. Expansion medium according to one of claims 1 to 5, characterized in that the composition contains the growth factors EGF and PDGF-BB, PDGF-AA or PDGF-AB.

7. expansion medium according to any one of claims 1 to 6, comprising: Component 1 L Medium final concentration

Ready culture medium with high

Glucose content (eg Dulbecco ^' s Modified

Eagle Medium (D-MEM) (1x) liquid (high

Glucose) (Invitrogen)) 567.5 ml

Finished culture medium with addition of

Trace elements (e.g., MCDB 201 (Sigma)) 400 ml

Supplement 20 ml

- human insulin 10 mg

- human transferrin 10 mg

- Sodium selenite 10 μg

Pen ici 11 i n / Streptomyces 10 ml 1% (v / v)

Ascorbic acid 2-phosphate 1, 5 mg 580 ul 0.1 mM

PRP (3 to 6.5-fold increased concentration) 30 ml 3% (v / v) rh EGF 250 μl 10 ng / ml rh PDGF-BB, rh PDGF-AA or rh PDGF-AB 250 μl 10 ng / ml

8. expansion medium according to one of claims 1 to 7, characterized in that the stem cells are cultured under suitable cultivation conditions over a long period and / or their rapid expansion without differentiation and while maintaining the ability to divide achievable.

9. expansion medium according to any one of claims 1 to 8 for the in vitro cultivation of mesenchymal stem cells.

10. A method for propagating stem cells in vitro, characterized in that the stem cells are propagated in an expansion medium without xenogeneic additives, which contains the components required for the growth of stem cells, platelet-rich plasma (PRP) and at least one growth factor.

11. The method according to claim 10, characterized in that PRP is used with a 3 to 6.5-fold increased concentration of platelets compared to whole blood.

12. The method of claim 10 or 11 using human PRP.

13. The method according to any one of claims 10 to 12 using different growth factors.

14. The method according to any one of claims 10 to 13 using recombinant human / Vachstumsfaktoren.

15. The method according to any one of claims 10 to 14 using the growth factors EGF and PDGF-BB, PDGF-AA or PDGF-AB.

16. The method according to any one of claims 10 to 15, characterized in that the expansion medium contains the following formulation:

Component 1 L Medium final concentration

Ready culture medium with high

Glucose content (eg Dulbecco ^' s Modified

Eagle Medium (D-MEM) (1x) liquid (high

Glucose) (Invitrogen)) 567.5 ml

Finished culture medium with addition of

Trace elements (e.g., MCDB 201 (Sigma)) 400 ml

Supplement 20 ml

- human insulin 10 mg

- human transferrin 10 mg

- Sodium selenite 10 μg penicillin / streptomycin 10 ml 1% (v / v)

Dexamethasone (20 μg / ml in 1 ml of ethanol and 45 ml of H ₂ O) 4 40000 μμll 0.02 μM Ascorbic acid 2-phosphate 1, 5 mg 580 μl 0.1 mM PRP (3 to 6.5-fold increased concentration) 30 ml 3% (v / v) rh EGF 250 μl 10 ng / ml rh PDGF-BB, rh PDGF-AA or rh PDGF-AB 250 μl 10 ng / ml

17. The method according to any one of claims 10 to 16, characterized in that mesenchymal stem cells from the bone marrow aspirate of donors are propagated.

18. The method according to any one of claims 10 to 17 for the propagation of human mesenchymal stem cells from a primary culture of a donor to a number of> 10 ⁶ cells.

19. Use of the method according to any one of claims 10 to 18 in the expansion medium according to any one of claims 1 to 9 propagated stem cells for transplantation or reimplantation in a recipient organism.

20. Use according to claim 19 for transplantation or reimplantation on and / or in a carrier material.

21. Use according to claim 19 or 20 of the method according to claim 17 or 18 increased mesenchymal stem cells for the treatment of a bone, cartilage, connective tissue, nerve, vascular or sehnendefekts.