Improved long-term durability of allogeneic heart valves in the orthotopic sheep model
| Autor: | Eva Brauchle, Christophe T. Arendt, Anna Biermann, Valentina O. Puntmann, Eike Nagel, Ulrich A. Stock, Sherif Abdelaziz, Julia Marzi, Katja Schenke-Layland, Julian L. Wichmann, Andreas Winter, Kelvin G. M. Brockbank, Shannon L. Layland |
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| Rok vydání: | 2018 |
| Předmět: |
Pulmonary and Respiratory Medicine
Pathology medicine.medical_specialty Time Factors medicine.medical_treatment 030204 cardiovascular system & hematology Matrix (biology) Cryopreservation 03 medical and health sciences 0302 clinical medicine Valve replacement In vivo medicine Animals Heart valve Bioprosthesis Sheep biology business.industry General Medicine medicine.disease Allografts Transplantation medicine.anatomical_structure 030228 respiratory system Heart Valve Prosthesis Models Animal biology.protein Surgery Cardiology and Cardiovascular Medicine business Elastin Calcification |
| Zdroj: | European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 55(3) |
| ISSN: | 1873-734X |
| Popis: | OBJECTIVES Frozen cryopreservation (FC) with the vapour phase of liquid nitrogen storage (-135°C) is a standard biobank technique to preserve allogeneic heart valves to enable a preferable allograft valve replacement in clinical settings. However, their long-term function is limited by immune responses, inflammation and structural degeneration. Ice-free cryopreserved (IFC) valves with warmer storage possibilities at -80°C showed better matrix preservation and decreased immunological response in preliminary short-term in vivo studies. Our study aimed to assess the prolonged performance of IFC allografts in an orthotopic pulmonary sheep model. METHODS FC (n = 6) and IFC (n = 6) allografts were transplanted into juvenile Merino sheep. After 12 months of implantation, functionality testing via 2-dimensional echocardiography and histological analyses was performed. In addition, multiphoton autofluorescence imaging and Raman microspectroscopy analysis were applied to qualitatively and quantitatively assess the matrix integrity of the leaflets. RESULTS Six animals from the FC group and 5 animals from the IFC group were included in the analysis. Histological explant analysis showed early inflammation in the FC valves, whereas sustainable, fully functional, devitalized acellular IFC grafts were obtained. IFC valves showed excellent haemodynamic data with fewer gradients, no pulmonary regurgitation, no calcification and acellularity. Structural remodelling of the leaflet matrix structure was only detected in FC-treated tissue, whereas IFC valves maintained matrix integrity comparable to that of native controls. The collagen crimp period and amplitude and elastin structure were significantly different in the FC valve cusps compared to IFC and native cusps. Collagen fibres in the FC valves were less aligned and straightened. CONCLUSIONS IFC heart valves with good haemodynamic function, reduced immunogenicity and preserved matrix structures have the potential to overcome the known limitations of the clinically applied FC valve. |
| Databáze: | OpenAIRE |
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