Editorial: Advancing Tissue Engineering and Regenerative Medicine

Biofabrication of Tissue-Engineered Cartilage Constructs Through Faraday Wave Bioassembly of Cell-Laden Gelatin Microcarriers

Acoustic biofabrication is an emerging strategy in tissue engineering due to its mild and fast manufacturing process. Herein, tissue-engineered cartilage constructs with high cell viability are fabricated from cell-laden gelatin microcarriers (GMs) through Faraday wave bioassembly, a typical acoustic "bottom-up" manufacturing process. Assembly modules are first prepared by incorporating cartilage precursor cells, the chondrogenic cell line ATDC5, or bone marrow-derived mesenchymal stem cells (BMSCs), into GMs. Patterned structures are formed by Faraday wave bioassembly of the cell-laden GMs. Due to the gentle and efficient assembly process and the protective effects of microcarriers, cells in the patterned structures maintain high activity. Subsequently, tissue-engineered cartilage constructs are obtained by inducing cell differentiation of the patterned structures. Comprehensive evaluations are conducted to verify chondrocyte differentiation and the formation of cartilage tissue constructs in terms of cell viability, morphological analysis, gene expression, and matrix production. Finally, implantation studies with a rat cartilage defect model demonstrate that these tissue-engineered cartilage constructs are beneficial for the repair of articular cartilage damage in vivo. This study provides the first biofabrication of cartilage tissue constructs using Faraday wave bioassembly, extending its application to engineering tissues with a low cell density.

Tissue-Engineered Constructions in Biophysics, Neurology and Other Fields and Branches of Medicine

This paper describes the gangliopexy method, a method for creating a new center of local neurohumoral regulation, based on the formation of new connections discovered between the nervous system and the vascular system. The prospects for the development of this method are studied. At the same time, novel concepts about the cycles of nitric oxide and the superoxide anion radical are introduced. A possible role of these cycles is examined in the protection of cells and the body as a whole against oxidative and nitrosative stress, which develops when (in 5-30% of cases) destructive changes in the displaced ganglion lead to vascular complications and an increased risk of mortality. Mechanisms that can protect nerve cells, prevent the development of destructive changes in these cells and reduce the risk of mortality are also investigated.

Current status and perspectives on stem cell-based therapies undergoing clinical trials for regenerative medicine: case studies

BACKGROUND

Apart from haematopoietic stem cell transplantation for haematological disorders many stem cell-based therapies are experimental. However, with only 12 years between human embryonic stem cell isolation and the first clinical trial, development of stem cell products for regenerative medicine has been rapid and numerous clinical trials have begun to investigate their therapeutic potential.

SOURCE OF DATA

This review summarizes key clinical trial data, current and future perspectives on stem cell-based products undergoing clinical trials, based on literature search and author research.

AREAS OF AGREEMENT

It is widely recognized that the ability to stimulate stem cell differentiation into specialized cells for use as cellular therapies will revolutionize health care and offer major hope for numerous diseases for which there are limited or no therapeutic options.

AREAS OF CONTROVERSY

Stem cell-based products are unique and cover a large range of disorders to be treated; therefore, there is significant potential for variation in cell source, type, processing manipulation, the bioprocessing approach and scalability, the cost and purity of manufacture, final product quality and mode of action. As such there are gaps in regulatory and manufacturing frameworks and technologies, only a small number of products are currently within late phase clinical trials and few products have achieved commercialization.

GROWING POINTS

Recent developments are encouraging acceleration through the difficulties encountered en route to clinical trials and commercialization of stem cell therapies.

AREAS TIMELY FOR DEVELOPING RESEARCH

The field is growing year on year with the first clinical trial using induced pluripotent stem cells anticipated by end 2013.

The frontiers of organ transplantation and cell therapy

The biggest problem in the area of organ transplantation is often the mismatch between supply and demand. Extrapolating the transplant waiting lists in Spain at the end of a year to the global population, more than one million people would be able to benefit from a transplant if there were enough available organs and adequate infrastructure. The first frontier and the most important is therefore the donation of organs. The aim of this chapter is to set out the most notable points concerning the various themes (donation, rejection, xenotrasnplants, tissue transplantation and stem cells therapy), and describe new avenues to be explored: The frontiers that it will be necessary to cross in order to continue the progress in saving lives and improving the health of hundreds of thousands of people across world.In the last years, embryonic stem cells have become in the great hope of many millions of patients across the world. In theory, the possibility to have unlimited quantities of these cells, to culture them, and to make them differentiate into cells of the liver, nervous system or heart would in fact become the ideal solution for the treatment of millions of patients. It is quite plausible that what organ transplantation has represented in the 20th century, bringing down taboos and saving hundreds of thousands of lives, is going to be replaced by stem cell therapy in the 21st Century.

Current understanding and challenges in bioprocessing of stem cell-based therapies for regenerative medicine

BACKGROUND

A novel manufacturing industry is emerging to translate unique cellular therapy bioprocesses to robust, scaled manufacturing production for successful clinical translation.

SOURCE OF DATA

This review summarizes key translational issues, and current and future perspectives to improve translation of cell-based therapy bioprocessing, based on literature search and author research.

AREAS OF AGREEMENT

It is widely recognized that cell-based therapies could revolutionize health care for a range of diseases, and that there are gaps in the overarching framework and technologies to generate clinical success.

AREAS OF CONTROVERSY

There is limited understanding of how to fulfil requirements as regulatory and manufacturing guidelines are incomplete and few have achieved commercialization.

GROWING POINTS

Recent developments are encouraging adoption of automation and quality engineering approaches for bioprocessing of cell-based therapies.

AREAS TIMELY FOR DEVELOPING RESEARCH

Include technology development to improve the cost and purity of manufacture and final product quality.

Tissue engineering by self-assembly and bio-printing of living cells

Biofabrication of living structures with desired topology and functionality requires the interdisciplinary effort of practitioners of the physical, life and engineering sciences. Such efforts are being undertaken in many laboratories around the world. Numerous approaches are pursued, such as those based on the use of natural or artificial scaffolds, decellularized cadaveric extracellular matrices and, most lately, bioprinting. To be successful in this endeavor, it is crucial to provide in vitro micro-environmental clues for the cells resembling those in the organism. Therefore, scaffolds, populated with differentiated cells or stem cells, of increasing complexity and sophistication are being fabricated. However, no matter how sophisticated scaffolds are, they can cause problems stemming from their degradation, eliciting immunogenic reactions and other a priori unforeseen complications. It is also being realized that ultimately the best approach might be to rely on the self-assembly and self-organizing properties of cells and tissues and the innate regenerative capability of the organism itself, not just simply prepare tissue and organ structures in vitro followed by their implantation. Here we briefly review the different strategies for the fabrication of three-dimensional biological structures, in particular bioprinting. We detail a fully biological, scaffoldless, print-based engineering approach that uses self-assembling multicellular units as bio-ink particles and employs early developmental morphogenetic principles, such as cell sorting and tissue fusion.