Validation of the shrinkage temperature of animal tissue for bioprosthetic heart valve application by differential scanning calorimetry

doi:10.1016/0142-9612(95)92125-P

Biomaterials

Volume 16, Issue 3, 1995, Pages 251-258

https://doi.org/10.1016/0142-9612(95)92125-P Get rights and content

Abstract

Shrinkage temperature is most often used to report the degree of cross-linking in glutaraldehyde-fixed animal tissue for use in bioprosthetic heart valve fabrication. Present practice utilizes the measurement of hydrothermal shrinkage observed when a sample is subjected to a temperature programme. This measurement at best gives a general indication of the efficiency of the treatment, i.e. the extent of cross-linking in the tissue. When differential scanning calorimetry has been used, the ambiguity arising from the scant reporting of the protocols used does not permit easy comparison of experimental results. This report addresses the considerations necessary to obtain optimum results in the differential scanning calorimetry experiment for the determination of shrinkage temperature in biological tissue. The shrinkage temperature of two previously unreported tissue types, porcine pericardium and equine pericardium, are provided and compared with those of bovine pericardium and porcine aortic valve leaflets.

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Cited by (53)

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Bioprosthetic heart valves (BHV) fabricated from heterograft tissue, such as glutaraldehyde pretreated bovine pericardium (BP), are the most frequently used heart valve replacements. BHV durability is limited by structural valve degeneration (SVD), mechanistically associated with calcification, advanced glycation end products (AGE), and serum protein infiltration. We investigated the hypothesis that anti-AGE agents, Aminoguanidine, Pyridoxamine [PYR], and N-Acetylcysteine could mitigate AGE-serum protein SVD mechanisms in vitro and in vivo, and that these agents could mitigate calcification or demonstrate anti-calcification interactions with BP pretreatment with ethanol. In vitro, each of these agents significantly inhibited AGE-serum protein infiltration in BP. However, in 28-day rat subdermal BP implants only orally administered PYR demonstrated significant inhibition of AGE and serum protein uptake. Furthermore, BP PYR preincubation of BP mitigated AGE-serum protein SVD mechanisms in vitro, and demonstrated mitigation of both AGE-serum protein uptake and reduced calcification in vivo in 28-day rat subdermal BP explants. Inhibition of BP calcification as well as inhibition of AGE-serum protein infiltration was observed in 28-day rat subdermal BP explants pretreated with ethanol followed by PYR preincubation. In conclusion, AGE-serum protein and calcification SVD pathophysiology are significantly mitigated by both PYR oral therapy and PYR and ethanol pretreatment of BP.
Sodium lignosulfonate cross-linked bioprosthetic heart valve materials for enhanced cytocompatibility, improved hemocompatibility, and reduced calcification
2022, Composites Part B: Engineering
Bioprosthetic heart valves (BHVs) are widely used to treat valvular disease. Almost all commercial BHVs are treated with glutaraldehyde (Glut). However, Glut-treated BHVs still have problems such as cytotoxicity, thrombosis, and calcification. This study focused on enhancing the performance of BHVs by cross-linking porcine pericardium (PP) with sodium lignosulfonate (SLS). Compared with Glut-PP, Human umbilical vein endothelial cells proliferation in the SLS-PP increased 13.3-fold at day 5, the adhesion of serum albumin and fibrinogen in SLS-PP decreased by 5.4-fold and 4.3-fold, and the calcification of SLS-PP decreased from 112.64 μg/mg to 13.49 μg/mg. SLS cross-linked PP(SLS-PP) was similar to Glut cross-linked PP(Glut-PP) in mechanical and enzymatic degradation resistance. In conclusion, SLS is a potential alternative for glutaraldehyde as a new cross-linker for BHVs.
Nonglutaraldehyde treated porcine pericardium with good biocompatibility, reduced calcification and improved Anti-coagulation for bioprosthetic heart valve applications
2021, Chemical Engineering Journal
Heart valve diseases, such as valve stenosis and regurgitation, are one of the important reasons for the high morbidity and mortality of cardiovascular diseases, and the heart valve replacement has become the optimal option for severe heart valve disease treatment. With the development of transcatheter heart valve replacement technology and aging population, the usage of bioprosthetic heart valves (BHVs) has been largely expanded. As the golden standard reagent, glutaraldehyde (Glut) has been widely used to fix tissues and most commercial BHVs are manufactured from Glut-treated porcine or bovine pericardial tissues. However, some drawbacks such as calcification, coagulation, poor biocompatibility, endothelialization difficulties are still unresolved for the Glut-treated BHVs owing to the toxicity of Glut, which will severely shorten the durability of BHVs and emerge as a big challenge for its application in the younger-aged patients. In this work, BHVs treated by bicyclic hydromethyl-oxazolidine (OX-OH) has been successfully prepared from porcine pericardium (PP) tissue. Compared with Glut-treated PP (Glut-PP), beside the satisfactory physical and chemical properties similar to Glut-PP, OX-OH treated PP (OX-OH-PP) also exhibits excellent biocompatibility, reduced anti-calcification, improved anti-coagulation and proliferation of endothelial cells. In addition, OX-OH-PP has been processed to be a transcatheter aortic valve product, which exhibits desirable hydrodynamic performance and passes the durability test of more than 350 million times without any perforation, tearing and delamination, meeting the relevant industry standard for transcatheter aortic valve products. The excellent biocompatibility, reduced anti-calcification, improved anti-coagulation and endothelialization, and high durability make OX-OH-PP a great potential in the clinical applications of BHVs.
Quasi-isothermal modulated DSC as a valuable characterisation method for soft tissue biomaterial crosslinking reactions
2020, Bioactive Materials
Citation Excerpt :
This provides a gauge to the degree of crosslinking within a fixed tissue. The test method followed a heating rate of 5 °C/min as suggested by Loke et al. [28] in a temperature range of 30 °C–100 °C. An empty aluminium pan was used as the reference.
Glutaraldehyde (Glut) is an extensively used sterilant and fixative for the crosslinking of natural soft tissue biomaterials like bovine pericardium (BP) to provide stability and is required for its application in vivo. There is plenty of debate around the reaction mechanism of Glut with natural biomaterials. Differential scanning calorimetry (DSC) is a commonly used technique that is typically used to measure the thermal profile of polymers. However, a variation known as quasi-isothermal modulated differential scanning calorimetry (QiMDSC) has been utilised for the analysis of polymorphic transformations in both the pharmaceutical and food industries. This communication will address QiMDSC as a method for analysing soft tissue biomaterials and their crosslinking mechanisms and how it can be applied to other biomaterial applications.
Assessment of the uniaxial experimental parameters utilised for the mechanical testing of bovine pericardium
2019, Journal of the Mechanical Behavior of Biomedical Materials
Citation Excerpt :
Heating was carried out in a nitrogen atmosphere of 50 ml/min. The Td can be calculated from the extrapolated onset or the peak temperature of the endothermic phenomena, here the peak temperature was used to determine the Td (Oswal et al., 2007; Loke and Khor, 1995; Tattini et al., 2007). Calibration of the instrument was carried out using an Indium standard (Melting point, Tm 156.6 °C).
Bovine pericardium (BP) is an extensively used biomaterial utilised in a wide range of biomedical devices such as bioprosthetic heart valves. However, the mechanical testing techniques that assess soft biomaterial tissue like BP are varied with no common method utilised across the literature, producing variations and contradictions in reported values. Uniaxial testing is a common technique used to measure traditional mechanical characteristics of ultimate tensile strength (UTS), modulus and the percentage strain at failure. The aim of this study was to take two standard uniaxial test parameters, strain rate and the number of preconditioning cycles and to elucidate recommendations for the standardisation of a uniaxial method, while also measuring not so common parameters of low modulus and hysteresis. Samples post uniaxial testing were treated and analysed with scanning electron microscopy (SEM) and an imaging software (ImageJ) to measure the effect of the parameters on the crimping structure and orientation of the collagen fibres. The study recommends an extension rate of 10 mm/min and 5 preconditioning load-unload cycles as a starting point for the standardisation of a uniaxial testing method. The image analysis of the collagen structure carried out provides a quantitative assessment of the BP post mechanical testing and allows for a better understanding of the behaviour of BP under stress.
Assessment of collagen-based materials which are supports of cultural and historical objects
2008, Polymer Degradation and Stability
Citation Excerpt :
The parameters Tonset, Tmin and ΔH corresponding to each investigated collagen-based material are listed in Table 1. As pointed out by several authors (e.g. [24]) the values of Tonset are close to those of the shrinkage temperature (Ts), as measured by thermal microscopy, and increase with the increasing rigidity of the amorphous matrix. The rigidity of the matrix is also related to the value of the peak temperature, Tmin.
The thermal degradation of collagen-based materials, viz. collagen, recently manufactured parchments and tanned leathers, a heritage parchment and patrimonial (historical) leathers, was investigated by thermal analysis methods. With progressive heating, all these materials exhibit three main successive processes, associated with dehydration, protein denaturation and pyrolysis/oxidation. The analysis of both denaturation and thermo-oxidation revealed significant differences between aged leather, collagen, recently manufactured parchments and tanned leathers in terms of the number of overlapping processes (reflected in the number of peaks recorded at denaturation) and of the oxidative degradation rates, given by the normalised curves of differential thermal gravimetry (DTG). The various observations are proposed as qualitative indices for assessing the age and storage conditions of leather. A three-phase model was used for explaining the results. This consists of crystalline collagen filaments that are embedded in an amorphous matrix with an interface zone between the crystalline and amorphous regions. Solid-state ¹H NMR investigations corroborate the thermal analysis results and enhance the understanding of the ageing processes.

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Validation of the shrinkage temperature of animal tissue for bioprosthetic heart valve application by differential scanning calorimetry

Abstract

Biochim Biophys Acta

Int J Biol Macromol

Examination of fixative penetration in glutaraldehyde-treated bovine pericardium by stratigraphic analysis of shrinkage temperature measurements using differential scanning calorimetry

Life Supp Syst

Mechanism of crosslinking of proteins by glutaraldehyde I

Connect Tiss Res

Mechanism of crosslinking of proteins by glutaraldehyde II

Connect Tiss Res

Mechanism of crosslinking of proteins by glutaraldehyde III

Connect Tiss Res

The nature of the crosslinking of proteins by glutaraldehyde. Part I. Interaction of glutaraldehyde with the amino-groups of 6-aminohexanoic acid and of α-N-acetyl-lysine

J Chem Soc, Perkin Trans

Collagen crosslinking and resorption: effect of glutaraldehyde concentration

Artif Organs

Phase transitions in collagen and gelatin systems

J Am Chem Soc