First, the need for human embryonic tissue
has to be minimized.
12] What is needed for valid consent to donate embryonic tissue
for research purposes?
The Geron EAB provides one guideline for how to show respect to embryonic tissue
in research: the research must "incorporate substantive values such as the reduction of human suffering.
Researchers at Kyoto University in Japan studied the efficacy of embryonic tissue
grafts in regenerating the ventral cochlear tract (VCT), the auditory pathway that helps conduct information received by the inner ear to hearing centers in the brain.
Finally, if a patient's own stem cells can be reprogrammed as needed, a major obstacle to use of embryonic tissue
-- the danger that the body may reject foreign tissue -- would pose no problem.
Damsky study the trophoblast, the outer layer of embryonic tissue
that implants into the uterine wall.
However, there is a theoretical possibility that birth defects might results when fragile embryonic tissue
is bombarded with sound waves.
Normally this pathway regulates fundamental developmental processes such as embryonic tissue
patterning and stem cell maintenance.
Since 1987, several research groups have identified peptide growth factors, all derived from adult frogs, that trigger development of nerve cells when added to cultured frog embryonic tissue
, Melton notes -- but none of the compounds induced eye and brain formation.
The experiment goes a step beyond other embryonic tissue
transplants that have been shown, for example, to boost the production of the neurochemical dopamine in the brain.
Stem cells may be sourced from fetal or embryonic tissue
or from adult tissue reservoirs such as bone marrow.
Stem cells from bone marrow hold the promise to be just as effective as embryonic stem cells, without posing the moral or ethical issues inherent in the use of embryonic tissue