Stem cells in modern medicine: Reality or myth?

Human amniotic-fluid-derived stem cells: a unique source for regenerative medicine

INTRODUCTION

The first application of tissue engineering was based on the use of differentiated cells from the adult organism, which was associated with an invasiveness and high risk of diseased cells' transplantation. Over the years, the range of available cell populations for tissue engineering has widened.

AREAS COVERED

We review the comprehensive information concerning the characteristic features of amniotic-fluid-derived stem cells (AFSCs). We also review the potential applications of these cells in clinical practice.

EXPERT OPINION

AFSCs hold promise for the future treatment of many incurable diseases. However, such cell-based therapies have some limitations, and there are questions relating to the use of stem cells, which should be carefully analyzed before translation of these cells into clinical practice.

Ethical aspects of tissue engineering: a review

Tissue engineering (TE) is a promising new field of medical technology. However, like other new technologies, it is not free of ethical challenges. Identifying these ethical questions at an early stage is not only part of science's responsibility toward society, but also in the interest of the field itself. In this review, we map which ethical issues related to TE have already been documented in the scientific literature. The issues that turn out to dominate the debate are the use of human embryonic stem cells and therapeutic cloning. Nevertheless, a variety of other ethical aspects are mentioned, which relate to different phases in the development of the field. In addition, we discuss a number of ethical issues that have not yet been raised in the literature.

Detection and characterization of hepatic engraftment of embryonic stem derived cells by fluorescent stereomicroscopy

BACKGROUND

Embryonic stem (ES) cells have been investigated as a potential replacement therapy for failed organs, such as the liver. However, detection of hepatic engraftment from candidate stem cells has been difficult due to low engraftment efficiency. Previous detection methods required that the graft be processed by molecular and/or immunohistochemical techniques, limiting further functional studies. This study evaluated the use of three-dimensional fluorescent stereomicroscopy for gross detection of ES cell derived hepatic engraftment.

MATERIAL AND METHODS

Murine ES cells expressing the enhanced green fluorescence protein (EGFP) underwent directed endodermal lineage differentiation. Three days after two thirds partial hepatectomy, cells were injected into the liver parenchyma, and livers were harvested at 10 to 20 d and examined by fluorescence stereomicroscopy with a GFP2 long pass filter (100447084; Leica Microsystems AG, Wetzlar, Germany). The sensitivity and reliability of the test was evaluated using quantitative polymerase chain reaction (q-PCR) to assay for the presence of EGFP mRNA in the tissue.

RESULTS

Fluorescent microscopy detected EGFP-positive cells engrafted with normal histology in 5 of 11 specimens. EGFP mRNA was confirmed in all five specimens by q-PCR. Only one of the 11 specimens was negative by fluorescence stereomicroscopy and positive by q-PCR, P < 0.02, Fisher's exact test.

CONCLUSION

Utilization of three-dimensional stereomicroscopy with a GFP2 long pass filter is a powerful and fast screening tool for GFP-ES derived hepatic engraftment.

Biopharmaceuticals: recent approvals and likely directions

Some 160 biopharmaceuticals have now gained medical approval and several hundred are in the pipeline. Most are protein-based, although two nucleic acid-based products are now on the US/European market. An increasing proportion of approvals are engineered in some way and advances in alternative production systems and delivery methods will also likely impact upon the approvals profile over the remainder of this decade.