Embryonic Stem Cell Research and Its Controversies

Introduction

Embryonic stem cells, the original building blocks of life, are the body's founder cells. Being undifferentiated in nature and capable of self—renewal, they can differentiate into any kind of tissue (www.explore-stemcells.co.uk). They are isolated from the developing embryo. An ovum and a sperm fertilize to form a zygote, which serially divides to develop into a ball of loosely connected cells, called a morula, by the fourth day of development. The morula then gives rise to an inner and an outer cell mass, which transform into an embryo and extraembryonic tissue (necessary for the initial development of embryo), respectively. The inner cell mass gives rise to three germinal layers—ectoderm, endoderm, and meso—derm—which go on to form different organs and tissues as the embryo matures.

History

Embryonic Stem Cells were first identified in the 1980s in animal models, and the breakthrough of their successful isolation from human embryonic tissue came after about two decades. They are derived from embryos that are in their initial stages of development. After an ovum is fertilized by a sperm, a zygote is formed, which then transforms into a loose clump of cells, called the morula, around the fourth day of embryonic development. (stemcells.nih.gov)

The morula then forms an inner and an outer cell mass, which transform into embryonic and extra embryonic tissue (necessary for the initial development of the embryo), respectively. The inner cell mass gives rise to three germinal lay—ers—ectoderm, endoderm, and mesoderm—which go on to form different organs and tissues as the embryo matures. Embryonic stem cells are derived from the inner cell mass around day four or day five postfertilization. After isolation, the embryonic stem cells are cultured in the laboratory.

Embryonic stem cells are derived from the inner cell mass of the blastocytes around day four or five postfertilization (stemcells.nih.gov). After isolation, the embryonic stem cells are cultured in the laboratory, and the stem cell lines are obtained with the potential to differentiate into various kinds of cells when provided with a cytokine cocktail in a suitable environment.

So far, using animal models, researchers have successfully isolated stem cells and shown them to differentiate into various types of cells in both in vitro (outside the body in an artificial environment) and in vivo (within the body) studies. Successful differentiation of embryonic stem cells into neural, vascular, and other solid organ cells was an important milestone that provided enough evidence for scientists to reproduce similar experiments, using human embryonic stem cells. Stem cells therefore were obtained from human embryos that were otherwise to be discarded following in vitro fertilization (a scientific approach to fertilization).

Government Policy and Research

A stem cell policy was immediately drafted by the U.S. government in August 2001 that restrained scientists from using federal funding to obtain any further stem cells by destroying human embryos. However, it allowed them to continue to work on the almost 60 embryonic stem cell lines that had already been obtained or for which the derivation process had been initiated before the policy's ...