Calcification of Various Bioprosthetic Materials in Rats: Is It Really Different?

Abstract

The causes of heart valve bioprosthetic calcification are still not clear. In this paper, we compared the calcification in the porcine aorta (Ao) and the bovine jugular vein (Ve) walls, as well as the bovine pericardium (Pe). Biomaterials were crosslinked with glutaraldehyde (GA) and diepoxide (DE), after which they were implanted subcutaneously in young rats for 10, 20, and 30 days. Collagen, elastin, and fibrillin were visualized in non-implanted samples. Atomic absorption spectroscopy, histological methods, scanning electron microscopy, and Fourier-transform infrared spectroscopy were used to study the dynamics of calcification. By the 30th day, calcium accumulated most intensively in the collagen fibers of the GA-Pe. In elastin-rich materials, calcium deposits were associated with elastin fibers and localized differences in the walls of Ao and Ve. The DE-Pe did not calcify at all for 30 days. Alkaline phosphatase does not affect calcification since it was not found in the implant tissue. Fibrillin surrounds elastin fibers in the Ao and Ve, but its involvement in calcification is questionable. In the subcutaneous space of young rats, which are used to model the implants’ calcification, the content of phosphorus was five times higher than in aging animals. We hypothesize that the centers of calcium phosphate nucleation are the positively charged nitrogen of the pyridinium rings, which is the main one in fresh elastin and appears in collagen as a result of GA preservation. Nucleation can be significantly accelerated at high concentrations of phosphorus in biological fluids. The hypothesis needs further experimental confirmation.

In Vitro Study of Composite Cements on Mesenchymal Stem Cells of Palatal Origin

“…This fact indicates that these experimental materials are compatible with the living body. Data in the literature report an increased level of alkaline phosphatase when the implant bio-integrates; the ALP peak usually occurs at 14 days after in vivo implantation [ 58 , 59 ]. It might facilitate the high-efficacy integration of composite cement into the teeth structure, although this requires further in vivo investigation for our composite samples.…”

In vivo application of a glutaraldehyde-free, UVA/riboflavin cross-linked bovine pericardium confirms suitability for cardiovascular substitutes

“…In addition, serum C-reactive protein levels were measured in an endpoint analysis. Within the small blood count variables [hematocrit, hemoglobin concentration, mean corpuscular hemoglobin, 37 mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular volume (MCV)], no significant changes were observed one and four weeks after implantation, compared to sham control (Table S5, supplementary material). When the material groups were compared with each other, juvenile rats receiving SULEEI pericardial discs showed a significantly higher hematocrit (47.3 ± 1.0%, n = 9) and hemoglobin concentration (10.3 ± 0.2 mmol/l, n = 9) compared to recipients of GA-treated implants 12 weeks after implantation (43.9 ± 0.6% and 9.6 ± 0.2 mmol/l, n = 9, Table S5, supplementary material).…”