Cadaver donation: structural integrity of pulmonary homografts harvested 48 h post mortem in the juvenile ovine model

Bester, Dreyer; Botes, Lezelle; Heever, Johannes Jacobus van den; Kotzé, Harry F.; Dohmen, Pascal M.; Pomar, José L.; Smit, Francis E.

doi:10.1007/s10561-018-9729-7

Cited by 7 publications

(13 citation statements)

References 22 publications

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“…In alliance with the EDQM guidelines, a blood sample is required from the donor for serological testing within 24 h of death to avoid hemolysis. After preparation, antibiotic decontamination is conducted for a minimum of 24 h and a maximum of 96 h. The allowed extended time spans lead to a larger pool of possible donors, and more time to retrieve and transport the hearts to the tissue bank (Axelsson and Malm 2018 ; Bester et al 2018 ).…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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

et al. 2023

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“…No calcific deposits are visible in any of the samples on von Kossa staining ( Figure 4 B,E,H), while large numbers of elastin fibers (black arrows) are clearly demonstrated in the ventricularis region of the leaflets in all three groups on modified van Gieson staining ( Figure 4 C,F,I). The collagen in the cryopreserved group appeared more collapsed compared to fresh untreated tissue [ 8 ], and compared to the cryopreserved group, more loosely arranged in the decellularized group and more compact and dense in the decellularized plus EnCap TM -treated group.…”

Section: Resultsmentioning

confidence: 99%

“…SEM demonstrated a confluent endothelial cell layer on the leaflet and wall tissue of cryopreserved homografts, even after 48 h of ischaemia ( Figure 6 A,B). These endothelial cells presented with prominent nuclei and collapsed extranuclear areas, indicative of non-viable cells [ 8 ]. Shenke–Layland and co-workers described the presence of limited collagen-containing structures in the ventricularis of cryopreserved valve leaflets after thawing, with significantly altered and deteriorated collagenous and elastic fiber structures as a result of crystal ice formation in the ECM during cryopreservation [ 40 ].…”

Section: Discussionmentioning

confidence: 99%

“…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 ]. The effect of cryopreservation on the collagen scaffold might be of greater importance in determining the long-term survival of the homograft than the impact of extending the post-mortem ischaemic time prior to harvesting.…”

Section: Introductionmentioning

confidence: 99%

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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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“…For example, naturally occurring and experimental aortic stenosis has been investigated in dogs ( Copeland et al, 1974 ; Kim et al, 1986 ; Ahlstrom Ast et al, 2008 ). Sheep are routinely used as a big animal model to investigate calcification of biological aortic valve prosthesis and homografts in vivo ( Kheradvar et al, 2017 ; Theodoridis et al, 2017 ; Bester et al, 2018 ). Apparently, calcification occurs very rapidly in sheep compared to humans.…”

Section: Animal Modelsmentioning

confidence: 99%

Models and Techniques to Study Aortic Valve Calcification in Vitro, ex Vivo and in Vivo. An Overview

Bogdanova

Zabirnyk²,

Malashicheva³

et al. 2022

Front. Pharmacol.

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Aortic valve stenosis secondary to aortic valve calcification is the most common valve disease in the Western world. Calcification is a result of pathological proliferation and osteogenic differentiation of resident valve interstitial cells. To develop non-surgical treatments, the molecular and cellular mechanisms of pathological calcification must be revealed. In the current overview, we present methods for evaluation of calcification in different ex vivo, in vitro and in vivo situations including imaging in patients. The latter include echocardiography, scanning with computed tomography and magnetic resonance imaging. Particular emphasis is on translational studies of calcific aortic valve stenosis with a special focus on cell culture using human primary cell cultures. Such models are widely used and suitable for screening of drugs against calcification. Animal models are presented, but there is no animal model that faithfully mimics human calcific aortic valve disease. A model of experimentally induced calcification in whole porcine aortic valve leaflets ex vivo is also included. Finally, miscellaneous methods and aspects of aortic valve calcification, such as, for instance, biomarkers are presented.

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Cadaver donation: structural integrity of pulmonary homografts harvested 48 h post mortem in the juvenile ovine model

Cited by 7 publications

References 22 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

Models and Techniques to Study Aortic Valve Calcification in Vitro, ex Vivo and in Vivo. An Overview

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