Sterilized xenograft tissue

• US 20030068815A1
• Filed: 05/17/2002
• Published: 04/10/2003
• Est. Priority Date: 02/11/1999
• Status: Abandoned Application

• Current Assignee: CROSSMARK Incorporated
• Original Assignee: CROSSMARK Incorporated
• Inventors: Stone, Kevin R., Turek, Thomas J.
• Application Number:
  US10/150,670
• Publication Number:
  US 20030068815A1
• Time in Patent Office: Days
• US Class Current: 435/325
• CPC Class Codes: A01N 1/00 Preservation of bodies of humans or animals, or parts thereof
• CPC Class Codes: A61F 2/08 Muscles; Tendons; Ligaments sutures A61B17/04
• CPC Class Codes: A61F 2/2412 with soft flexible valve members, e.g. tissue valves shaped like natural valves check valves with flexible valve members in general F16K15/14
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61K 35/34 Muscles; Smooth muscle cells; Heart; Cardiac stem cells; Myoblasts; Myocytes; Cardiomyocytes vascular smooth muscle A61K35/44
• CPC Class Codes: A61L 2/0035 Gamma radiation
• CPC Class Codes: A61L 2/0047 Ultraviolet radiation
• CPC Class Codes: A61L 2/007 Particle radiation, e.g. electron-beam, alpha or beta radiation
• CPC Class Codes: A61L 2/0094 Gaseous substances
• CPC Class Codes: A61L 2/08 Radiation
• CPC Class Codes: A61L 2/10 Ultraviolet radiation
• CPC Class Codes: A61L 2/20 Gaseous substances, e.g. vapours
• CPC Class Codes: A61L 2/202 Ozone
• CPC Class Codes: A61L 2/206 Ethylene oxide
• CPC Class Codes: A61L 2430/40 Preparation and treatment of biological tissue for implantation, e.g. decellularisation, cross-linking
• CPC Class Codes: A61L 27/3604 : characterised by the human or animal origin of the biological material, e.g. hair, fascia, fish scales, silk, shellac, pericardium, pleura, renal tissue, amniotic membrane, parenchymal tissue, fetal tissue, muscle tissue, fat tissue, enamel
• CPC Class Codes: A61L 27/3625 : Vascular tissue, e.g. heart valves
• CPC Class Codes: A61L 27/3683 : subjected to a specific treatment prior to implantation, e.g. decellularising, demineralising, grinding, cellular disruption/non-collagenous protein removal, anti-calcification, crosslinking, supercritical fluid extraction, enzyme treatment
• CPC Class Codes: A61L 27/3687 : characterised by the use of chemical agents in the treatment, e.g. specific enzymes, detergents, capping agents, crosslinkers, anticalcification agents
• CPC Class Codes: A61L 27/3691 : characterised by physical conditions of the treatment, e.g. applying a compressive force to the composition, pressure cycles, ultrasonic/sonication or microwave treatment, lyophilisation

Abstract

The invention provides an article of manufacture comprising a substantially non-immunogenic xenograft for implantation into humans. The invention also provides methods for preparing a xenograft by removing at least a portion of a soft tissue from a non-human animal to provide a xenograft; washing the xenograft in saline and alcohol; subjecting the xenograft to cellular disruption treatment; treating the xenograft with crosslinking agents, and digesting the xenograft with a proteoglycan-depleting factor and/or glycosidase. The invention further provides a method for sterilizing xenograft material, having the steps of obtaining substantially non-immunogenic xenograft material; treating the xenograft material with at least one crosslinking agent; and subjecting the crosslinked xenograft material to radiation treatment.

Claims

1. A method of sterilizing xenograft material for implantation into a human, comprising the steps of:

(1) obtaining substantially non-immunogenic xenograft material;

(2) treating the xenograft material with at least one crosslinking agent; and

(3) subjecting the crosslinked xenograft material to radiation treatment.

2. The method of claim 1, wherein the xenograft material is substantially depleted in carbohydrate chains having terminal α

-galactosyl sugar at the non-reducing end of the carbohydrate chain.

3. The method of claim 1, wherein the substantially non-immunogenic xenograft is substantially depleted in a proteoglycans.

4. The method of claim 1, wherein the substantially non-immunogenic xenograft material is soft tissue.

5. The method of claim 1, wherein the substantially non-immunogenic xenograft material is heart valve tissue.

6. The method of claim 1, wherein the substantially non-immunogenic xenograft material is porcine.

7. The method of claim 1, wherein the substantially non-immunogenic xenograft material is sterilized.

8. The method of claim 7, wherein the sterilizing is by with one or more agents selected from the group consisting of ethylene oxide, and propylene oxide.

9. The method of claim 1, wherein the crosslinking agent is selected from the group consisting of aldehydes, aromatic diamines, carbodiimides, and diisocyanates.

10. The method of claim 1, wherein at least one crosslinking agent is glutaraldehyde.

11. The method of claim 1, wherein the crosslinking agent is a solution containing about 0.01 percent to about 5 percent glutaraldehyde.

12. The method of claim 1, wherein a crosslinking treatment is by exposing the xenograft material to a crosslinking agent in a vapor form.

13. The method of claim 1, wherein the radiation treatment comprises range of sterilization dose to the from 15.8 kGy to 21.3 kGy.

14. The method of claim 1, wherein the radiation treatment comprises a validated sterilization dose of 17.8 kGy.

15. The method of claim 1, wherein the radiation treatment is by electron beam irradiation or gamma irradiation.

16. The method of claim 1, wherein the sterilized xenograft material has a sterility assurance level of at least 10⁻

6.

17. The method of claim 1, wherein the sterilized xenograft material is substantially free of a virus selected from the group consisting of porcine parvovirus, influenza A, pseudorabies virus and reovirus 3.

18. The method of claim 1, wherein the sterilized xenograft material is substantially free of a transmissible spongiform encephalopathy (TSE) agent.

19. The method of claim 1, wherein the sterilized xenograft material has substantially the same mechanical properties as the native heart valve.

20. A method of preparing a xenograft material for implantation into a human, comprising the steps of:

(a) obtaining soft tissue xenograft material from a non-human animal;

(b) washing the xenograft material in water and alcohol;

(c) subjecting the xenograft material to a cellular disruption treatment; and

(d). treating the xenograft material with a glycosidase to remove a plurality of first surface carbohydrate moieties, wherein

(i) the glycosidase treatment occurs in a glycosidase process solution; and

(ii) during the glycosidase treatment, the head-space of the glycosidase process solution is subjected to vacuum to remove air trapped in the xenograft material;

whereby the xenograft material is substantially non-immunogenic and has substantially the same mechanical properties as a preselected human tissue.

21. The method of claim 20, wherein the vacuum is between 10 and 1000 millitorr.

22. The method of claim 20, wherein the vacuum is between 50 and 500 millitorr.

23. The method of claim 20, wherein the vacuum treatment is continuous.

24. The method of claim 20, wherein the vacuum treatment is pulsed.

25. The method of claim 20, wherein the glycosidase is a galactosidase.

26. The method of claim 25, wherein the galactosidase is an α

-galactosidase.

27. The method of claim 20, further comprising the step of depleting substantially a plurality of proteoglycans from the xenograft material.

28. The method of claim 27, wherein the proteoglycan depleting step comprises digesting the xenograft with at least one proteoglycan-depleting factor selected from the group consisting of chondroitinase ABC, hyaluronidase, chondroitin AC II lyase, keratanase, trypsin and fibronectin fragment.

29. The method of claim 27, wherein:

(a) the proteoglycan depleting step occurs in a proteoglycan depleting process solution; and

(b) during the proteoglycan depleting step, the head-space of the proteoglycan depleting process solution is subjected to vacuum to remove air trapped in the xenograft material.

30. The method of claim 20, further comprising the step of treating the xenograft material with at least one crosslinking agent.

31. The method of claim 30, wherein the crosslinking agent is selected from the group consisting of aldehydes, aromatic diamines, carbodiimides, and diisocyanates.

33. The method of claim 30, wherein:

(a) the crosslinking treatment occurs in a crosslinking process solution; and

(b) during the crosslinking treatment, the head-space of the crosslinking process solution is subjected to vacuum to remove air trapped in the xenograft material.

34. The method of claim 20, further comprising the step of treating the xenograft material with at least one enzyme.

35. The method of claim 34, wherein the enzyme is selected from the group consisting of ficin and trypsin.

36. The method of claim 34, wherein:

(a) the enzyme treatment occurs in an enzyme process solution; and

(b) during the enzyme treatment, the head-space of the enzyme process solution is subjected to vacuum to remove air trapped in the xenograft material.

37. The method of claim 20, further comprising the step of treating the xenograft material with one or more agents selected from the group consisting of anticalcification agents, antithrombotic agents, antibiotics, growth factors and polyethylene glycol.

38. The method of claim 37, wherein:

(a) the treatment occurs in a process solution; and

(b) during the treatment, the head-space of the process solution is subjected to vacuum to remove air trapped in the xenograft material.

32. The method of claim 230, wherein at least one crosslinking agent is glutaraldehyde.