The feasibility of gamma radiation sterilization for decellularized tracheal grafts

Christopher M. Johnson, De Huang Guo, Stephanie Ryals, Gregory N Postma, Paul M. Weinberger

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Objectives/Hypothesis: The most promising stem cell-derived tracheal transplantation approach is dependent upon the use of decellularized tracheal grafts. It has been assumed that a sterilization step, such as gamma radiation, would damage the delicate extracellular matrix of the graft, thus rendering it less viable for cellular repopulation, although this has not been thoroughly investigated. Study Design: Laboratory-based comparative analysis. Methods: Fifteen murine tracheas of strain C57/B-6 mice were obtained. Thirteen were subjected to a detergent-enzymatic decellularization process. Of these decellularized tracheas (DT), eight were irradiated, exposing five tracheas to a radiation level of 25 kGy (DT25) and three to 5 kGy (DT5). Two were left untreated. The two untreated tracheas, two DTs, and two DT25s were prepared and examined using both scanning and transmission electron microscopy. Bioburden calculations were obtained from three DTs, three DT25s, and three DT5s by homogenization, serial dilution, and streak plating. Results: Electron microscopy of untreated fresh tracheas and DTs showed a slight qualitative degradation of cartilage ultrastructure due to the decellularization process. In contrast, examination of DT25 shows significant degradation including poor overall preservation of cartilage architecture with disorganized collagen fibers. The nonirradiated DTs had a calculated bacterial bioburden of 7.8 × 107 to 3.4 × 108 colony-forming units per gram. Both the DT25 and DT5 specimens were found to have a bioburden of zero. Conclusions: Gamma radiation at 25 kGy degrades the architecture of decellularized tracheal grafts. These ultrastructural changes may prove detrimental to graft viability; however, bioburden calculations suggest that a 5 kGy radiation dose may be sufficient for sterilization. Level of Evidence: NA Laryngoscope, 127:E258–E264, 2017.

Original languageEnglish (US)
Pages (from-to)E258-E264
JournalLaryngoscope
Volume127
Issue number8
DOIs
StatePublished - Aug 1 2017

Fingerprint

Gamma Rays
Trachea
Transplants
Cartilage
Stem Cells
Radiation
Laryngoscopes
Scanning Transmission Electron Microscopy
Detergents
Extracellular Matrix
Electron Microscopy
Collagen
Transplantation

Keywords

  • Implant sterilization
  • allograft
  • animal models
  • bioburden
  • biological burden
  • cartilage graft
  • electron microscopy
  • medical implant
  • mouse trachea
  • terminal sterilization
  • tracheal reconstruction
  • tracheal stenosis
  • tracheal transplant
  • ultrastructure

ASJC Scopus subject areas

  • Otorhinolaryngology

Cite this

The feasibility of gamma radiation sterilization for decellularized tracheal grafts. / Johnson, Christopher M.; Guo, De Huang; Ryals, Stephanie; Postma, Gregory N; Weinberger, Paul M.

In: Laryngoscope, Vol. 127, No. 8, 01.08.2017, p. E258-E264.

Research output: Contribution to journalArticle

Johnson, Christopher M. ; Guo, De Huang ; Ryals, Stephanie ; Postma, Gregory N ; Weinberger, Paul M. / The feasibility of gamma radiation sterilization for decellularized tracheal grafts. In: Laryngoscope. 2017 ; Vol. 127, No. 8. pp. E258-E264.
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abstract = "Objectives/Hypothesis: The most promising stem cell-derived tracheal transplantation approach is dependent upon the use of decellularized tracheal grafts. It has been assumed that a sterilization step, such as gamma radiation, would damage the delicate extracellular matrix of the graft, thus rendering it less viable for cellular repopulation, although this has not been thoroughly investigated. Study Design: Laboratory-based comparative analysis. Methods: Fifteen murine tracheas of strain C57/B-6 mice were obtained. Thirteen were subjected to a detergent-enzymatic decellularization process. Of these decellularized tracheas (DT), eight were irradiated, exposing five tracheas to a radiation level of 25 kGy (DT25) and three to 5 kGy (DT5). Two were left untreated. The two untreated tracheas, two DTs, and two DT25s were prepared and examined using both scanning and transmission electron microscopy. Bioburden calculations were obtained from three DTs, three DT25s, and three DT5s by homogenization, serial dilution, and streak plating. Results: Electron microscopy of untreated fresh tracheas and DTs showed a slight qualitative degradation of cartilage ultrastructure due to the decellularization process. In contrast, examination of DT25 shows significant degradation including poor overall preservation of cartilage architecture with disorganized collagen fibers. The nonirradiated DTs had a calculated bacterial bioburden of 7.8 × 107 to 3.4 × 108 colony-forming units per gram. Both the DT25 and DT5 specimens were found to have a bioburden of zero. Conclusions: Gamma radiation at 25 kGy degrades the architecture of decellularized tracheal grafts. These ultrastructural changes may prove detrimental to graft viability; however, bioburden calculations suggest that a 5 kGy radiation dose may be sufficient for sterilization. Level of Evidence: NA Laryngoscope, 127:E258–E264, 2017.",
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AU - Johnson, Christopher M.

AU - Guo, De Huang

AU - Ryals, Stephanie

AU - Postma, Gregory N

AU - Weinberger, Paul M.

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N2 - Objectives/Hypothesis: The most promising stem cell-derived tracheal transplantation approach is dependent upon the use of decellularized tracheal grafts. It has been assumed that a sterilization step, such as gamma radiation, would damage the delicate extracellular matrix of the graft, thus rendering it less viable for cellular repopulation, although this has not been thoroughly investigated. Study Design: Laboratory-based comparative analysis. Methods: Fifteen murine tracheas of strain C57/B-6 mice were obtained. Thirteen were subjected to a detergent-enzymatic decellularization process. Of these decellularized tracheas (DT), eight were irradiated, exposing five tracheas to a radiation level of 25 kGy (DT25) and three to 5 kGy (DT5). Two were left untreated. The two untreated tracheas, two DTs, and two DT25s were prepared and examined using both scanning and transmission electron microscopy. Bioburden calculations were obtained from three DTs, three DT25s, and three DT5s by homogenization, serial dilution, and streak plating. Results: Electron microscopy of untreated fresh tracheas and DTs showed a slight qualitative degradation of cartilage ultrastructure due to the decellularization process. In contrast, examination of DT25 shows significant degradation including poor overall preservation of cartilage architecture with disorganized collagen fibers. The nonirradiated DTs had a calculated bacterial bioburden of 7.8 × 107 to 3.4 × 108 colony-forming units per gram. Both the DT25 and DT5 specimens were found to have a bioburden of zero. Conclusions: Gamma radiation at 25 kGy degrades the architecture of decellularized tracheal grafts. These ultrastructural changes may prove detrimental to graft viability; however, bioburden calculations suggest that a 5 kGy radiation dose may be sufficient for sterilization. Level of Evidence: NA Laryngoscope, 127:E258–E264, 2017.

AB - Objectives/Hypothesis: The most promising stem cell-derived tracheal transplantation approach is dependent upon the use of decellularized tracheal grafts. It has been assumed that a sterilization step, such as gamma radiation, would damage the delicate extracellular matrix of the graft, thus rendering it less viable for cellular repopulation, although this has not been thoroughly investigated. Study Design: Laboratory-based comparative analysis. Methods: Fifteen murine tracheas of strain C57/B-6 mice were obtained. Thirteen were subjected to a detergent-enzymatic decellularization process. Of these decellularized tracheas (DT), eight were irradiated, exposing five tracheas to a radiation level of 25 kGy (DT25) and three to 5 kGy (DT5). Two were left untreated. The two untreated tracheas, two DTs, and two DT25s were prepared and examined using both scanning and transmission electron microscopy. Bioburden calculations were obtained from three DTs, three DT25s, and three DT5s by homogenization, serial dilution, and streak plating. Results: Electron microscopy of untreated fresh tracheas and DTs showed a slight qualitative degradation of cartilage ultrastructure due to the decellularization process. In contrast, examination of DT25 shows significant degradation including poor overall preservation of cartilage architecture with disorganized collagen fibers. The nonirradiated DTs had a calculated bacterial bioburden of 7.8 × 107 to 3.4 × 108 colony-forming units per gram. Both the DT25 and DT5 specimens were found to have a bioburden of zero. Conclusions: Gamma radiation at 25 kGy degrades the architecture of decellularized tracheal grafts. These ultrastructural changes may prove detrimental to graft viability; however, bioburden calculations suggest that a 5 kGy radiation dose may be sufficient for sterilization. Level of Evidence: NA Laryngoscope, 127:E258–E264, 2017.

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KW - electron microscopy

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KW - mouse trachea

KW - terminal sterilization

KW - tracheal reconstruction

KW - tracheal stenosis

KW - tracheal transplant

KW - ultrastructure

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