::Whats All This Hype About Stem Cells?

Introduction: What are stem cells, and why are they important?

Stem Cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

Stem cells are distinguished from other cell types by two important characteristics. First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions. Until recently, scientists primarily worked with two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells. The functions and characteristics of these cells will be explained in this document. Scientists discovered ways to derive embryonic stem cells from early mouse embryos nearly 30 years ago, in 1981. The detailed study of the biology of mouse stem cells led to the discovery, in 1998, of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through in vitro fertilization procedures. When they were no longer needed for that purpose, they were donated for research with the informed consent of the donor. In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be "reprogrammed" genetically to assume a stem cell-like state. This new type of stem cell, called induced pluripotent stem cells (iPSCs), will be discussed in a later section of this document.

Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lung, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.

Given their unique regenerative abilities, stem cells offer new potentials for treating diseases such as diabetes, and heart disease. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine. Laboratory studies of stem cells enable scientists to learn about the cells' essential properties and what makes them different from specialized cell types. Scientists are already using stem cells in the laboratory to screen new drugs and to develop model systems to study normal growth and identify the causes of birth defects. Research on stem cells continues to advance knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. Stem cell research is one of the most fascinating areas of contemporary biology, but, as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries.
Latest Breakthrough's
A BRITISH teenager has undergone a groundbreaking operation using stem cells to regenerate her cancerous windpipe. The 19-year-old and another 31-year-old Czech patient have been discharged after undergoing the groundbreaking procedure in Florence, Italy. Both were suffering from a rare form of trachea cancer and needed new windpipes. Doctors regenerated tissue from the patients' noses and bone marrow stem cells to create tracheas biologically identical to the patients' original organs. Unlike previous operations on trachea transplants, this was the first time stem cells were used to grow new tracheas outside the body. Because the new tracheas contained no organic substance foreign to the patient, no anti-rejection drugs were needed.

Dr Walter Giovannini, from AOU Careggi Hospital in Florence, said the British woman was speaking after only three or four days after the operations on 3 and 13 July. He said: "This is a unique solution for a problem that had none, except the death of the patient. Surgeons have been making advances in the transplant of windpipes, but previous cases have mostly focused on patients whose windpipes have been physically damaged due to trauma. "While trachea cancer is rare, it is very difficult to treat because it is resistant to chemotherapy and radiation, and transplants of mechanical devices to replace the windpipe have not been effective. "It takes two to three months for the stem cells to completely cover the trachea, creating a new organ."

Dr Giovannini added: "In the meantime, the windpipe is functional without the cells - acting as a sort of mechanical device before the stem cells transform it into an organ.

Further reading and Information Courtesy: My Brain, Stem Cell Research.