Tissue decellularization

• US 7,318,998 B2
• Filed: 03/24/2003
• Issued: 01/15/2008
• Est. Priority Date: 04/11/1997
• Status: Expired due to Fees

• Current Assignee: Cryolife Incorporated
• Original Assignee: Cryolife Incorporated
• Inventors: Black, Kirby S., Goldstein, Steven
• Primary Examiner(s): REDDING, DAVID A
• Application Number:
  US10/394,576
• Publication Number:
  US 20030228692A1
• Time in Patent Office: 1,758 Days
• Field of Search: None
• US Class Current: 435/1.3
• CPC Class Codes: A61F 2/2415 Manufacturing methods
• CPC Class Codes: A61L 2400/02 Treatment of implants to prevent calcification or mineralisation in vivo
• 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 27/3683 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 27/3695 characterised by the function or physical properties of the final product, where no specific conditions are defined to achieve this A61L27/3687, A61L27/3691 take precedence
• CPC Class Codes: Y10S 623/915 Method or apparatus for preparing biological material
• CPC Class Codes: Y10S 623/916 Blood vessel
• CPC Class Codes: Y10S 623/918 Heart

Abstract

The present invention relates, in general, to tissue decellularization and, in particular to a method of treating tissues, for example, heart valves, tendons and ligaments, so as to render them acellular and thereby limit mineralization and/or immunoreactivity upon implementation in vivo.

Claims

1. A method of producing a bioprosthetic tissue consisting essentially of the of the steps of:

i) washing a starting tissue selected from the group consisting of a heart valve, tendon, ligament, artery, vein, diaphragm, pericardium, fascia, dura mater and tympanic membrane with a bioburden reducing agent so that said starting tissue is disinfected,

ii) subsequent to step (i), contacting said disinfected tissue with a hypotonic solution so that lysis of cells of said disinfected tissue is effected,

iii) incubating the hypotonic solution-treated tissue resulting from step (ii) with at least one enzyme, wherein said at least one enzyme consists of at least one nuclease, so that nucleic acid associated with said cells lysed as a result of step (ii) is degraded, and

iv) sterilizing the nuclease-treated tissue resulting from step (iii).

2. The method according to claim 1 wherein said method of production further consists essentially of, after step (iii), the step of contacting the tissue resulting from step (iii) with a physiologically isotonic solution.

3. The method according to claim 1 wherein said starting tissue is a human tissue.

4. The method according to claim 3 wherein said starting tissue is obtained from a human heart valve.

5. The method according to claim 1 wherein said tissue resulting from step (iii) is at least 70% decellularized.

6. The method according to claim 1 wherein said at least one enzyme consists of DNAase or RNAase.

7. The method according to claim 1 wherein said at least one enzyme consists of DNAase and RNAase.

8. The method according to claim 1 wherein said starting tissue is non-human tissue.

9. The method according to claim 1 wherein said bioburden reducing agent is an antibiotic or mixture of antibiotics.

10. The method according to claim 1 wherein said step (ii) is carried out at a temperature of between 30°

to 40°

C.

11. The method according to claim 1 wherein said method of production further consists essentially of, after step (i), the steps of cryopreserving said disinfected tissue and then thawing said cryopreserved, disinfected tissue.

12. The method according to claim 1 wherein, in step (ii), said hypotonic solution is water.