Impact of current cryopreservation procedures on mechanical and functional properties of human aortic homografts

Langerak, Susan E.; Groenink, Maarten; Wall, Ernst E. van der; Wassenaar, C; vanBavel, Ed; Spaan, Jos A. E.; Baal, M. C.

doi:10.1111/j.1432-2277.2001.tb00053.x

Cited by 28 publications

(7 citation statements)

References 39 publications

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“…Each heart was submerged in the 37 °C oxygenated low-sodium, high-potassium solution (in mM: 0.4KH 2 PO 4 ; 1.0MgSO 4 :7H 2 O; 28NaHCO 3 ; 1.5CaCl 2 :2H 2 O; 5.6 Dextrose; 117.5 L-Glutamic acid) for 30 min and treated with cryopreservation solution (15% dimethyl sulfoxide) before being stored in a −80 °C freezer until mechanical testing could be performed. Studies have shown that cryopreservation does not significantly modify the biomechanical properties of aortic tissue [12]. Human specimen characteristics are presented in Table 1.…”

Section: Methodsmentioning

confidence: 99%

Significant differences in the material properties between aged human and porcine aortic tissues

Martin

Pham

Sun

2011

European Journal of Cardio-Thoracic Surgery

111

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Objectives Currently, percutaneous aortic valve (PAV) replacement devices are being investigated to treat aortic stenosis in patients deemed to be of too high a risk for conventional open-chest surgery. Successful PAV deployment and function are heavily reliant on the tissue–stent interaction. Many PAV feasibility trials have been conducted with porcine models under the assumption that these tissues are similar to human; however, this assumption may not be valid. The goal of this study was to characterize and compare the biomechanical properties of aged human and porcine aortic tissues. Methods The biaxial mechanical properties of the left coronary sinus, right coronary sinus, non-coronary sinus, and ascending aorta of eight aged human (90.1 ± 6.8 years) and 10 porcine (6–9 months) hearts were quantified. Tissue structure was analyzed via histological techniques. Results Aged human aortic tissues were significantly stiffer than the corresponding porcine tissues in both the circumferential and longitudinal directions (p < 0.001). In addition, the nearly linear stress–strain behavior of the porcine tissues, compared with the highly nonlinear response of the human tissues at a low strain range, suggested structural differences between the aortic tissues from these two species. Histological analysis revealed that porcine samples were composed of more elastin and less collagen fibers than the respective human samples. Conclusions Significant material and structural differences were observed between the human and porcine tissues, which raise questions on the validity of using porcine models to investigate the biomechanics involved in PAV intervention.

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Section: Methodsmentioning

confidence: 99%

Significant differences in the material properties between aged human and porcine aortic tissues

Martin

Pham

Sun

2011

European Journal of Cardio-Thoracic Surgery

111

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“…Current elastin preservative strategies aim to (a) protect existing elastin against degradation by matrix metalloproteinases (MMP) [6] and elastases [7], (b) replace lost elastin structures (e.g., with synthetic elastomers [8,9], peptide-derived elastomers [10,11], allogeneic elastomers [12]), or (c) regenerate elastin matrices by providing appropriate elastogenic cues (e.g., scaffolds, growth factors). However these approaches have thus far met with only limited success due to non-identification of suitable biochemical cues that can upregulate inherently poor tropoelastin synthesis by adult vascular cells.…”

Section: Introductionmentioning

confidence: 99%

Impact of delivery mode of hyaluronan oligomers on elastogenic responses of adult vascular smooth muscle cells

2007

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Our prior studies demonstrated that exogenous supplements of pure hyaluronan (HA) tetramers (HA4) dramatically upregulate elastin matrix synthesis by adult vascular smooth muscle cells (SMCs). Some studies suggest that exogenous HA likely only transiently contacts and signals cells, and may elicit different cell responses when presented on a substrate (e.g., scaffold surface). To clarify such differences, we used a carbodiimide-based chemistry to tether HA4 onto glass, and compared elastin matrix synthesis by SMCs cultured on these substrates, with those cultured with equivalent amounts of exogenous HA4. Tethered HA4-layers were first characterized for homogeneity, topography, and hydrolytic stability using SEM, XPS, AFM, and FACE. In general, mode of HA4 presentation did not influence its impact on SMC proliferation, or cell synthesis of tropoelastin and matrix elastin, relative to non-HA controls; however, surface-tethered HA4 stimulated SMCs to generate significantly greater amounts of elastin-stabilizing desmosine crosslinks, which partially accounts for the greater resistance to enzymatic breakdown of elastin derived from these cultures. Elastin derived from both sets of cultures contained peptide masses that correspond to the predominant peptides present in rat aortic elastin. SEM and TEM showed that HA4 stimulated fibrillin-mediated elastin matrix deposition, and organization into fibrils. Surfaceimmobilized HA4 was particularly conducive to organization of elastin into aggregating fibrils, and their networking to form closely-woven sheets of elastin fibers, as seen in cardiovascular tissues. The results suggest that incorporation of elastogenic HA4 mers onto cell culture substrates or scaffolds is a better approach than exogenous supplementation for in vitro or in vivo regeneration of architecturally and compositionally faithful-, and more stable mimics of native vascular elastin matrices.

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“…26–30 Little attention, however, is paid to the actual cryopreservation base solution; usually, cells and tissues are simply frozen in supplemented cell culture medium with addition of cryoprotectants. 3–6,9,27,28,31 …”

Section: Discussionmentioning

confidence: 99%

“…5 However, very modest results are achieved with most current freezing protocols in terms of muscular and especially endothelial function and integrity. 6–9 In the clinical setting, an impaired endothelial lining induces platelet adhesion and clot formation, so it is highly desirable to preserve the endothelial layer of cryopreserved vessels for transplantation purposes. For vascular constructs in tissue engineering, very little experience exists in the field of storage/cryopreservation.…”

Section: Introductionmentioning

confidence: 99%

Serum- and albumin-free cryopreservation of endothelial monolayers with a new solution

2018

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Cryopreservation is the only long-term storage option for the storage of vessels and vascular constructs. However, endothelial barrier function is almost completely lost after cryopreservation in most established cryopreservation solutions. We here aimed to improve endothelial function after cryopreservation using the 2D-model of porcine aortic endothelial cell monolayers. The monolayers were cryopreserved in cell culture medium or cold storage solutions based on the 4°C vascular preservation solution TiProtec®, all supplemented with 10% DMSO, using different temperature gradients. After short-term storage at −80°C, monolayers were rapidly thawed and re-cultured in cell culture medium. Thawing after cryopreservation in cell culture medium caused both immediate and delayed cell death, resulting in 11 ± 5% living cells after 24 h of re-culture. After cryopreservation in TiProtec and chloride-poor modifications thereof, the proportion of adherent viable cells was markedly increased compared to cryopreservation in cell culture medium (TiProtec: 38 ± 11%, modified TiProtec solutions ≥ 50%). Using these solutions, cells cryopreserved in a sub-confluent state were able to proliferate during re-culture. Mitochondrial fragmentation was observed in all solutions, but was partially reversible after cryopreservation in TiProtec and almost completely reversible in modified solutions within 3 h of re-culture. The superior protection of TiProtec and its modifications was apparent at all temperature gradients; however, best results were achieved with a cooling rate of −1°C/min. In conclusion, the use of TiProtec or modifications thereof as base solution for cryopreservation greatly improved cryopreservation results for endothelial monolayers in terms of survival and of monolayer and mitochondrial integrity.

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Impact of current cryopreservation procedures on mechanical and functional properties of human aortic homografts

Cited by 28 publications

References 39 publications

Significant differences in the material properties between aged human and porcine aortic tissues

Significant differences in the material properties between aged human and porcine aortic tissues

Impact of delivery mode of hyaluronan oligomers on elastogenic responses of adult vascular smooth muscle cells

Serum- and albumin-free cryopreservation of endothelial monolayers with a new solution

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