Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms. The intrinsic biochemical properties of ROS, which underlie the mechanisms ne...

Reactive Oxygen Species (ROS)-Based Nanomedicine.

The discovery of mouse embryonic stem (ES) cells >20 years ago represented a major advance in biology and experimental medicine, as it enabled the routine manipulation of the mouse genome. Along with the capacity to induce genetic modifications, ES cells provided the basis for establishing an in vitro model of early mammalian development and represented a putative new source of differentiated cell types for cell replacement therapy. While ES cells have been used extensively for creating mouse mutants for more than a decade, their application as a model for developmental biology has been limited and their use in cell replacement therapy remains a goal for many in the field. Recent advances in our understanding of ES cell differentiation, detailed in this review, have provided new insights essential for establishing ES cell-based developmental models and for the generation of clinically relevant populations for cell therapy.

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Embryonic stem cell differentiation: emergence of a new era in biology and medicine

Embryonic stem cells have huge potential in the field of tissue engineering and regenerative medicine as they hold the capacity to produce every type of cell and tissue in the body. In theory, the treatment of human disease could be revolutionized by the ability to generate any cell, tissue, or even organ, 'on demand' in the laboratory. This work reviews the history of murine and human ES cell lines, including practical and ethical aspects of ES cell isolation from pre-implantation embryos, maintenance of undifferentiated ES cell lines in the cell culture environment, and differentiation of ES cells in vitro and in vivo into mature somatic cell types. Finally, we discuss advances towards the clinical application of ES cell technology, and some of the obstacles which must be overcome before large scale clinical trials can be considered.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2184.2004.00298.x

Embryonic stem cells.

Elastomeric biomaterials for tissue engineering

A review of trends and limitations in hydrogel-rapid prototyping for tissue engineering

Characterisation of a soft elastomer poly(glycerol sebacate) designed to match the mechanical properties of myocardial tissue

Driven by enormous clinical need, myocardial tissue engineering has become a prime focus of research within the field of tissue engineering. Myocardial tissue engineering combines isolated functional cardiomyocytes and a biodegradable or nondegradable biomaterial to repair diseased heart muscle. The challenges in heart muscle engineering include cell related issues (such as scale up in a short timeframe, efficiency of cell seeding or cell survival rate, and immune rejection), the design and fabrication of myocardial tissue engineering substrates, and the engineering of tissue constructs in vitro and in vivo. Several approaches have been put forward, and a number of models combining various polymeric biomaterials, cell sources and bioreactors have been developed in the last 10 years for myocardial tissue engineering. This review provides a comprehensive update on the biomaterials, as well as cells and biomimetic systems, used in the engineering of the cardiac muscle. The article is organized as follows. A historic perspective of the evolution of cardiac medicine and emergence of cardiac tissue engineering is presented in the first section. Following a review on the cells used in myocardial tissue engineering (second section), the third section presents a review on biomaterials used in myocardial tissue engineering. This section starts with an overview of the development of tissue engineering substrates and goes on to discuss the selection of biomaterials and design of solid and porous substrates. Then the applications of a variety of biomaterials used in different approaches of myocardial tissue engineering are reviewed in great detail, and related issues and topics that remain challenges for the future progress of the field are identified at the end of each subsection. This is followed by a brief review on the development of bioreactors (fourth section), which is an important achievement in the field of myocardial tissue engineering, and which is also related to the biomaterials developed. At the end of this article, the major achievements and remaining challenges are summarized, and the most promising paradigm for the future of heart muscle tissue engineering is proposed (fifth section).

Biomaterials in cardiac tissue engineering: Ten years of research survey

Myocardial tissue engineering, a concept that intends to overcome the obstacles to prolonging patients' life after myocardial infarction, is continuously improving. It comprises a biomaterial based 'vehicle', either a porous scaffold or dense patch, made of either natural or synthetic polymeric materials, to aid transportation of cells into the diseased region in the heart. Many different cell types have been suggested for cell therapy and myocardial tissue engineering. These include both autologous and embryonic stem cells, both having their advantages and disadvantages. Biomaterials suggested for this specific tissue-engineering application need to be biocompatible with the cardiac cells and have particular mechanical properties matching those of native myocardium, so that the delivered donor cells integrate and remain intact in vivo. Although much research is being carried out, many questions still remain unanswered requiring further research efforts. In this review, we discuss the various approaches reported in the field of myocardial tissue engineering, focusing on the achievements of combining biomaterials and cells by various techniques to repair the infarcted region, also providing an insight on clinical trials and possible cell sources in cell therapy. Alternative suggestions to myocardial tissue engineering, in situ engineering and left ventricular devices are also discussed.

Myocardial tissue engineering: a review.

Sources of data: In this review, we briefly discuss the current therapeutic options available to patients with heart failure post-myocardial infarction. We describe the various strategies currently proposed to encourage myocardial regeneration, with focus on the achievements in myocardial tissue engineering (MTE). We report on the current cell types, materials and methods being investigated for developing a tissue-engineered myocardial construct. Areas of agreement: Generally, there is agreement that a ‘vehicle’ is required to transport cells to the infarcted heart to help myocardial repair and regeneration. Areas of controversy: Suitable cell source, biomaterials, cell environment and implantation time post-infarction remain obstacles in the field of MTE. Growing points: Research is being focused on optimizing natural and synthetic biomaterials for tissue engineering. The type of cell and its origin (autologous or derived from embryonic stem cells), cell density and method of cell delivery are also being explored. Areas timely for developing research: The possibility is being explored that materials may not only act as a support for the delivered cell implants, but may also add value by changing cell survival, maturation or integration, or by prevention of mechanical and electrical remodelling of the failing heart.

/pdf/myocardial-tissue-engineering-so36wj5z65.pdf

Myocardial tissue engineering

Embryonic stem (ES) cell pluripotency is being investigated increasingly to obtain specific cell lineages for tissue engineering. However, the possibility that ES cells can give rise to lung tissue has not been tested. We hypothesized that lung epithelial cells (type II pneumocytes) can be derived in vitro from murine ES cells. After withdrawal of leukemia inhibitory factor (LIF) and formation of embryoid bodies in maintenance medium for 10, 20, and 30 days, differentiating ES cells were kept in the same medium or transferred to serum-free small airway growth medium (SAGM) for a further 3 or 14 days of culture. The presence of type II pneumocytes in the resulting mixed cultures was demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) of surfactant protein C (SPC) mRNA, immunostaining of SPC, and electron microscopy of osmiophilic lamellar bodies only at 30 days sampling time. SAGM appeared to be more favorable for type II cell formation than ES medium. No SPC transcripts were found in differentiating cells grown under the same conditions without formation of embryoid bodies. These findings could form the basis for the enrichment of ES cell-derived cultures with type II pneumocytes, and provide an in vitro system for investigating mechanisms of lung repair and regeneration.

Nadire N. Ali

Papers

Characterisation of a soft elastomer poly(glycerol sebacate) designed to match the mechanical properties of myocardial tissue

Biomaterials in cardiac tissue engineering: Ten years of research survey

Myocardial tissue engineering: a review.

Myocardial tissue engineering

Derivation of type II alveolar epithelial cells from murine embryonic stem cells