Scientists studying stem cells may hold the key for the thousands of people currently on the list for donor organs and the 17 candidates who die daily waiting for hearts, lungs, kidneys or livers that never come. Stem cells, which have the ability to adapt and regenerate into different cell types in the body, have the potential to replace tissues damaged by disease. It is hoped that such tissue engineering might someday help doctors eliminate the need for many transplants and the anti-rejection drugs used in transplantation.
Research in stem cell medical technology is in the infant stages and results are not expected for at least ten years. Though stem cell research has a long history, much is still unknown about them and few published studies meet rigorous scientific criteria. The current wave of research, which may produce results this decade, is for Parkinson's and Alzheimer's disease as well as treatments for strokes and paralysis.
A stem cell is a particular type of general cell with the properties of being self-renewing and unspecialized. A stem cell can regenerate itself, indefinitely, into a specific cell type, such as one specializing in bone, cartilage, fat, connective tissue, skin, muscle, islets, retinal networks, blood or another type of human cell.
Stem cells can be used to repair a diseased organ. Studies on mice are currently underway in the area of stem cells and transplantation. Stem cells from mice are injected into their diseased and infected hearts and are being trained to repair them. This method is in the early stages of treatment on humans and several such procedures were recently performed.
Cloning new organs from stem cells is another way that stem cells can aid people waiting for donor organs. Cloning is the act of reprogramming a cell by replacing its nucleus with that of another cell so it becomes the genetic equivalent of the original. This process, which is referred to as nuclear transfer, raises both hope as well as ethical concerns regarding the possibility of cloning humans for organs. Scientists are currently examining the possibility of instructing stem cells to build a new organ in a laboratory, which would eventually replace a damaged organ via surgery.
The goals of stem cell research are to evaluate the use of stem cell sources and demonstrate efficacy and safety in their ability to repair damaged tissues. The possibility and prevention of rejection must also be studied as well as controlling and directing the production of stem cells into the types of tissue, muscle, bone or organs as they are needed. Though research is currently being conducted on mice and primates, we do not know how cells will behave when transplanted into humans.