Time-dependent extracellular matrix alterations of young tendons in response to stress relaxation: a model for the Ponseti method.

The Ponseti method corrects a clubfoot by manipulation and casting which causes stress relaxation on the tendons. Here, we examined the effect of long-term stress relaxation on tendon extracellular matrix (ECM) by (1) an stress relaxation test, (2) an tenocyte culture with stress relaxation and (3) an rabbit study. Time-dependent tendon lengthening and ECM alterations including crimp angle reduction and cleaved elastin were observed, which illustrated the mechanism of tissue lengthening behind the treatment-a material-based crimp angle reduction resulted from elastin cleavage.

Development of Tri-Layered Biomimetic Atelocollagen Scaffolds with Interfaces for Osteochondral Tissue Engineering.

The development of biomimetic scaffolds containing cartilage, calcified cartilage, and bone regeneration for precise osteochondral repair remains a challenge. Herein, a novel tri-layered scaffold-with a top layer containing type II atelocollagen and chondroitin sulphate for cartilage regeneration, an intermediate layer with type II atelocollagen and hydroxyapatite for calcified cartilage formation, and a bottom layer with type I atelocollagen and hydroxyapatite for bone growth-that can be built using liquid-phase cosynthesis, is described. The tri-layered scaffolds are mechanically demonstrably superior and have a lower risk of delamination than monolayer scaffolds.

Physiological and pharmacological stimulation for in vitro maturation of substrate metabolism in human induced pluripotent stem cell-derived cardiomyocytes.

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) enable human cardiac cells to be studied in vitro, although they use glucose as their primary metabolic substrate and do not recapitulate the properties of adult cardiomyocytes. Here, we have explored the interplay between maturation by stimulation of fatty acid oxidation and by culture in 3D. We have investigated substrate metabolism in hiPSC-CMs grown as a monolayer and in 3D, in porous collagen-derived scaffolds and in engineered heart tissue (EHT), by measuring rates of glycolysis and glucose and fatty acid oxidation (FAO), and changes in gene expression and mitochondrial oxygen consumption.

Mechanical and Degradation Properties of Hybrid Scaffolds for Tissue Engineered Heart Valve (TEHV).

In addition to biocompatibility, an ideal scaffold for the regeneration of valvular tissue should also replicate the natural heart valve extracellular matrix (ECM) in terms of biomechanical properties and structural stability. In our previous paper, we demonstrated the development of collagen type I and hyaluronic acid (HA)-based scaffolds with interlaced microstructure. Such hybrid scaffolds were found to be compatible with cardiosphere-derived cells (CDCs) to potentially regenerate the diseased aortic heart valve.

Biomechanical Effects of Unidirectional Expansion Using Anisotropic Expanders in Horse Skin Tissue.

The use of a self-inflating tissue expander is a technique to stretch cutaneous tissues for potential use in reconstructive skin surgeries. This study investigates the mechanical properties of horse skin stretched by the subcutaneous implantation of anisotropic tissue expanders at the forehead, right shoulder, and dorsomedial part of the cannon region of the right forelimb in six (n = 6) horses. After 14 days of skin expansion, expanded and normal (control) skin samples were harvested and their mechanical properties of elastic modulus (EM), maximum force (MF), maximum stress (MSs) and maximum strain (MSr) were evaluated using uniaxial tension test.