The field of stem cells has been so clouded by controversy and misconceptions that few people truly understand what stem cells are, what their potential is and how much research is being done with them. In fact, when we asked people on the street to tell us about stem cells, the answers ranged from “cells that can help you stop smoking” to “ways to grow body parts” to even “a technique for choosing your baby’s gender and appearance”.
The reality is that stem cells are early stage cells that can divide and develop into various specialized cell types in the body. They can also self-renew to produce more stem cells.
There are two types of stem cells – embryonic stem cells and adult stem cells. In mammals, including humans, adult stem cells act as a repair system for the body, replenishing and healing adult tissue. These adult stem cells are found in children as well as adults and can be found in many tissues and organs.
What makes these cells exciting is their remarkable capacity to transform or become any number of different cell
types…with some limitations. Usually they can only become cells of the same tissue type. This means that adult stem cells could be used for what are called cell-based therapies, offering the possibility of a renewable source of replacement cells and tissues to treat diseases including Alzheimer’s disease, spinal cord injury, stroke, burns, heart disease, diabetes, arthritis and more.
So what are these remarkable cells? What do they look like? And, more importantly, what makes them different from – and more powerful than – most other cells? Let’s start with some highly simplified and abbreviated basic cell biology.
Most of us think of a cell as a ball of liquid or gel filled with a bunch of tiny structures just floating around inside. In fact, a cell is an incredibly complex and orderly organism where literally trillions of chemical reactions are happening every second. The outside of a cell is a semi-fluid envelope called the cell membrane. Embedded in the membrane are large sugar and protein molecules that regulate how things like nutrients and waste pass in and out of the cell as well as help transmit signals to the cells interior. The control center of the cell, the nucleus, contains genes made up of various combinations of DNA. Some genes help cells become bone… others to become skin, muscle, liver cells and so on. This is what’s called “differentiation.”