Category: General

J Biomech Eng. 2023 Mar 1;145(3):031009. doi: 10.1115/1.4056398.

ABSTRACT

In this work, we present a new experimental setup for the assessment of the anisotropic properties of Bovine Pericardium (BP) membranes. The chemically fixed BP samples have been subjected to a bulge test with in situ confocal laser scanning at increasing applied pressure. The high resolution topography provided by the confocal laser scanning has allowed to obtain a quantitative measure of the bulge displacement; after polynomial fitting, principal curvatures have been obtained and a degree of anisotropy (DA) has been defined as the normalized difference between the maximum and minimum principal curvatures. The experiments performed on the BP membranes have allowed us to obtain pressure-displacement data which clearly exhibit distinct principal curvatures indicating an anisotropic response. A comparison with curvatures data obtained on isotropic Nitrile Buthadiene Rubber (NBR) samples has confirmed the effectiveness of the experimental setup for this specific purpose. Numerical simulations of the bulge tests have been performed with the purpose of identifying a range of constitutive parameters which well describes the obtained range of DA on the BP membranes. The DA values have been partially validated with biaxial tests available in literature and with suitably performed uni-axial tensile tests.

PMID:36472464 | DOI:10.1115/1.4056398

Front Cardiovasc Med. 2023 Jan 6;9:1101929. doi: 10.3389/fcvm.2022.1101929. eCollection 2022.

ABSTRACT

A 10-year-old girl presented with obvious cyanosis, and the saturation of arterial blood oxygen (SpO₂) was decreased to 60.5% in the outpatient examination. Computed tomography angiography (CTA) and echocardiography suggested congenitally corrected transposition of the great arteries (ccTGAs), membranous ventricular septal aneurysm (MVSA), atrial septal defect (ASD), severe pulmonary stenosis (PS), and severe tricuspid regurgitation (TR). Due to the complex pathological anatomical structures, the three-dimensional printed model was used for preoperative assessment. After a comprehensive evaluation was completed, the operation was performed by physiological correction under cardiopulmonary bypass, including the resection of MVSA, repair using the bovine pericardial patch for ASD, and linear valvuloplasty of the tricuspid valve. Due to the special anatomical structures of ccTGA, PS was treated by extracardiac pipe technique. After the operation, the patient recovered well, cyanosis disappeared, SpO₂ was up to 96%, and the extracardiac pipe was well-functioning without regurgitation or obstruction.

PMID:36684563 | PMC:PMC9852815 | DOI:10.3389/fcvm.2022.1101929

Mater Today Bio. 2022 Oct 23;17:100451. doi: 10.1016/j.mtbio.2022.100451. eCollection 2022 Dec 15.

ABSTRACT

Cardiovascular surgery involves reconstruction of tissues that are under cyclical mechanical loading, and in constant contact with pulsatile blood flow. Durable biomaterials for such tissue reconstruction are scarce, as they need to be mechanically strong, hemocompatible, and resist structural deterioration from calcification. While homografts are ideal, they are scarce; xenografts are immunogenic and rendered inactive from glutaraldehyde fixation, causing them to calficy and structurally deteriorate over time; decellularized xenografts are devoid of cells, mechanically weak; and synthetic polymeric scaffolds are thrombogenic or too dense to enable host cell infiltration. In this work, we report the in vivo feasibility of a new polymer-decellularized matrix composite material (decellularized bovine pericardium-polycaprolactone: chitosan) fabricated by electrospinning, which is designed to be mechanically strong and achieve programmed host cell honing to integrate into the host. In a rodent and sheep model, this new material was found to be hemocompatible, and enabled host cell infiltration into the polymer and the decellularized matrix core underlying the polymer. Presence of M2 macrophages and several vascular cell types, with matrix remodeling in the vicinity of the cells was observed in the explanted tissues. In summary, the proposed composite material is a novel approach to create in-situ host integrating tissue substitutes, with better non-thrombogenicity, reduced infections and endocarditis, and potentially the ability to grow with the patient and remodeling into a native tissue structure.

PMID:36444341 | PMC:PMC9700326 | DOI:10.1016/j.mtbio.2022.100451