Does prolonged post-mortem cold ischemic harvesting time influence cryopreserved pulmonary homograft tissue integrity?

Smit, Francis E.; Bester, Dreyer; Heever, Johannes Jacobus van den; Schlegel, Franziska; Botes, Lezelle; Dohmen, Pascal M.

doi:10.1007/s10561-015-9500-2

Cited by 13 publications

(9 citation statements)

References 32 publications

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“…There are no other studies investigating the mechanical properties of the homograft vessel wall after different decontamination intervals. However, there are studies investigating other aspects of the homograft with mechanical testing (Smit et al 2015 ; Bester et al 2018 ; Fiala et al 2019 ). One study that evaluates homograft tissue after different cryopreservation intervals compared to fresh homografts presented similar values of the elastic modulus and tensile strength as in our study (Fiala et al 2019 ).…”

Section: Discussionmentioning

confidence: 99%

“…Studies evaluating different time spans during procurement in relation to long-term performance of the homograft after implantation, have not been able to show any clinical disadvantages of extended procurement times (Meyns et al 2005 ; Kalfa et al 2011 ; Smit et al 2015 ). Repeated studies have shown that prolonged time spans during procurement decrease cell viability of the homograft, but these findings have not shown any correlation to long-term outcome after implantation (Mochtar et al 1984 ; Angell et al 1989 ; Niwaya et al 1995 ; Gall et al 1998 ).…”

Section: Introductionmentioning

confidence: 99%

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Impact of storage time prior to cryopreservation on mechanical properties of aortic homografts

et al. 2023

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Optimal time spans in homograft procurement are still debatable among tissue banks and needs to be further investigated. Cell viability decreases at longer preparation intervals, but the effect on collagen and elastic fibers has not been investigated to the same extent. These fibers are of importance to the homograft elasticity and strength. The objective of this study was to analyze the mechanical properties of homograft tissue at different time spans in the procurement process. Ten aortic homografts were collected at the Tissue Bank in Lund. Twelve samples were obtained from each homograft, cryopreserved in groups of three after 2–4 days, 7–9 days, 28–30 days, and 60–62 days in antibiotic decontamination. Mechanical testing was performed with uniaxial tensile tests, calculating elastic modulus, yield stress and energy at yield stress. Two randomly selected samples were assessed with light microscopy. Procurement generated a total of 120 samples, with 30 samples in each time group. Elastic modulus and yield stress was significantly higher in samples cryopreserved after 2–4 days (2.7 MPa (2.5-5.0) and 0.78 MPa (0.68-1.0)) compared to 7–9 days (2.2 MPa (2.0-2.6) and 0.53 MPa (0.46–0.69)), p = 0.008 and 0.011 respectively. Light microscopy did not show any difference in collagen and elastin at different time spans. There was a significant decrease in elastic modulus and yield stress after 7 days of decontamination at 4 °C compared to 2–4 days. This could indicate some deterioration of elastin and collagen at longer decontamination intervals. Clinical significance of these findings remains to be clarified.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of storage time prior to cryopreservation on mechanical properties of aortic homografts

et al. 2023

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“…Mitchell et al (1998) reported the early death and loss of endothelial and interstitial cells in cryopreserved homografts following implantation, arguing that valve durability primarily relies on the retention of structural integrity and the preservation of the ECM instead of cell viability [ 37 ]. Smit et al has previously shown that the post-mortem ischaemic time prior to the cryopreservation of homografts can be extended safely to around 48 h [ 6 ].…”

Section: Discussionmentioning

confidence: 99%

“…This guideline restricts the available post-mortem donor pool significantly. Various efforts have been made to address the shortages in homograft availability, and our research group has proven that the post-mortem ischaemic time can be extended safely to around 48 h without affecting valve performance [ 6 ]. Although cryopreservation is currently the most frequently used and probably the best method for long-term storage of homografts [ 7 ], it does damage the collagen scaffold, irrespective of ischaemic harvesting time [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Impact of Three Different Processing Techniques on the Strength and Structure of Juvenile Ovine Pulmonary Homografts

et al. 2022

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Homografts are routinely stored by cryopreservation; however, donor cells and remnants contribute to immunogenicity. Although decellularization strategies can address immunogenicity, additional fixation might be required to maintain strength. This study investigated the effect of cryopreservation, decellularization, and decellularization with additional glutaraldhyde fixation on the strength and structure of ovine pulmonary homografts harvested 48 h post-mortem. Cells and cellular remnants were present for the cryopreserved group, while the decellularized groups were acellular. The decellularized group had large interfibrillar spaces in the extracellular matrix with uniform collagen distribution, while the additional fixation led to the collagen network becoming dense and compacted. The collagen of the cryopreserved group was collapsed and appeared disrupted and fractured. There were no significant differences in strength and elasticity between the groups. Compared to cryopreservation, decellularization without fixation can be considered an alternative processing technique to maintain a well-organized collagen matrix and tissue strength of homografts.

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“…The mechanical properties of pericardial samples were examined uniaxially, as previously described [15] based on a method described by [16,17]. In short, a Lloyds LF100 Plus tensile strength apparatus (IMP, Johannesburg, South Africa) was used to determine the tensile properties and the thickness of each tissue strip was determined using a MiniTest 137-735-F5HD (ElectroPhysk, Gernamy) thickness gauge.…”

Section: Tensile Strength and Elastic Modulusmentioning

confidence: 99%

The sequential effects of a multifactorial detergent based decellularization process on bovine pericardium

Laker

Dohmen

Smit

2020

Biomed. Phys. Eng. Express

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Decellularization is a promising method for obtaining extracellular matrix scaffolds (ECM) to be used as replacement material in reconstructive procedures. The effectiveness of decellularization and the alterations to the ECM vary, depending on several factors, including the tissue source, composition and density. With an optimized decellularization process, decellularized scaffolds can preserve the spatial and temporal ECM microenvironment, which play an integral role in modulating cell migration, proliferation and differentiation. The exploration of a variety of decellularization protocols has led to mixed outcomes and comparisons between decellularization protocols could not attribute these differences to any single step in a multiple-step process. This study aimed to characterize the effects of each step of a multifactorial decellularization method on the scaffold structure and mechanical integrity of bovine pericardium. Each step of the decellularization process and the effect on the tissue was assessed using hematoxylin and eosin staining, electron microscopy, total protein, ECM protein and triglyceride quantification. The biomechanical properties were assessed using uniaxial tensile strength testing. Cell lysis occurred mainly during the detergent and alcohol steps. Collagen structural damage occurred during the detergent and alcohol steps, with no significant decreased in collagen concentration. No significant damage to elastin could be shown throughout the process, however glycosaminoglycans were significantly removed by detergent treatment. Triglycerides were removed mostly by the alcohol treatment. The strength of the pericardium decreased somewhat after each step of the protocol. It is important to characterize each decellularization protocol with regards to the decellularization efficiency and the effect on the ECM proteins structure and function to accurately evaluate in vivo outcomes.

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Does prolonged post-mortem cold ischemic harvesting time influence cryopreserved pulmonary homograft tissue integrity?

Cited by 13 publications

References 32 publications

Impact of storage time prior to cryopreservation on mechanical properties of aortic homografts

Impact of storage time prior to cryopreservation on mechanical properties of aortic homografts

Impact of Three Different Processing Techniques on the Strength and Structure of Juvenile Ovine Pulmonary Homografts

The sequential effects of a multifactorial detergent based decellularization process on bovine pericardium

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