Footprint-free human induced pluripotent stem cells from articular cartilage with redifferentiation capacity: a first step toward a clinical-grade cell source.

Human induced pluripotent stem cells (iPSCs) are potential cell sources for regenerative medicine; however, clinical applications of iPSCs are restricted because of undesired genomic modifications associated with most reprogramming protocols. We show, for the first time, that chondrocytes from autologous chondrocyte implantation (ACI) donors can be efficiently reprogrammed into iPSCs using a nonintegrating method based on mRNA delivery, resulting in footprint-free iPSCs (no genome-sequence modifications), devoid of viral factors or remaining reprogramming molecules. The search for universal allogeneic cell sources for the ACI regenerative treatment has been difficult because making chondrocytes with high matrix-forming capacity from pluripotent human embryonic stem cells has proven challenging and human mesenchymal stem cells have a predisposition to form hypertrophic cartilage and bone.

Nanosized fibers' effect on adult human articular chondrocytes behavior.

Tissue engineering with chondrogenic cell based therapies is an expanding field with the intention of treating cartilage defects. It has been suggested that scaffolds used in cartilage tissue engineering influence cellular behavior and thus the long-term clinical outcome. The objective of this study was to assess whether chondrocyte attachment, proliferation and post-expansion re-differentiation could be influenced by the size of the fibers presented to the cells in a scaffold.

Optimization of a chondrogenic medium through the use of factorial design of experiments.

The standard culture system for in vitro cartilage research is based on cells in a three-dimensional micromass culture and a defined medium containing the chondrogenic key growth factor, transforming growth factor (TGF)-β1. The aim of this study was to optimize the medium for chondrocyte micromass culture. Human chondrocytes were cultured in different media formulations, designed with a factorial design of experiments (DoE) approach and based on the standard medium for redifferentiation.

Bipolar radiofrequency plasma ablation induces proliferation and alters cytokine expression in human articular cartilage chondrocytes.

Purpose: The aim of the study was to determine the in vitro effects of plasma-mediated bipolar radiofrequency ablation on human chondrocyte compensatory proliferation and inflammatory mediator expression.

Methods: Human articular cartilage biopsy specimens, from total knee replacement, and human chondrocytes in alginate culture, from patients undergoing autologous chondrocyte implantation, were exposed to plasma ablation with a Paragon T2 probe (ArthroCare, Austin, TX). Instantaneous chondrocyte death was investigated with live/dead assays of biopsy specimens and cell cultures.

Triphasic and quadriphasic waveforms are superior to biphasic waveforms for synchronized beating of cardiomyocytes.

Background And Purpose: Within pacemaker research few attempts have been made to find an optimal waveform phase sequence that synchronizes beating of cardiomyocytes at an electrode. Multielectrode arrays (MEAs) offer electrophysiological screening of cardiomyocytes serving as a system for preliminary screening of pacing waveform design.

Materials And Methods: The HL-1 cell line was cultured in MEAs until confluence and stimulated with biphasic, triphasic, and quadriphasic waveforms.