Stem cells

What are stem cells?

undifferentiated cells that can differentiate into any other type of cell

How do stem cells compare to specialised cells?

They have the ability to differenciate into different types of cell therefore can produce cells by mitosis to replace damaged tissue. Once a cell has specialised it is unable to change into another type of cell

Where do we obtain stem cells from?

Plants = meristems - growing points in the tips and shoots and roots

Animals = adult stem cells (bone marrow, umbilical cord) embryonic stem cells (embryos left over in vitro fertility (IVF) treatment

How do embryonic stem cells differ from adult cells?

• Embryonic stem cells are found in early embryos; they have the potential to differentiate into any cell type

• Adult stem cells are only found in certain locations, e.g. bone marrow, and can only differentiate into a few different cell types

Stem cells be used for a number of medical reasons including:

• Repair damaged cells

• treatment / cure to diseases

Advantages of using stem cells as a medical tool

• No rejection

• No need to find a donor

• No need for tissue typing

Clinical issues

• difficulty in finding suitable donors

• no guarantee it will work

• difficulty in obtaining and storing a patients embryonic stem cells

• mutations have been observed in stem cells

• cultured stem cells could be contaminated

Ethical issues

• Is it right to create embryos to be destroyed?

• One source of embryo stem cells is unused embryo’s produced by IVF

• viewed as a commodity

• what stage of an embryo is considered a person?

Social issues

• lack of education available to explain what stem cells can and cannot be used for

• patients could be exploited

• do the benefits outweigh the risks

• storing the cells is expensive

• lack of peer-reviewed clinical evidence of the success of stem cell treatment means that there is a level of distrust