What are Stem Cells and How Do They Work

Regenerative medicine may be the fastest growing, most exciting branch of medical research and development today. It is a newer type of research and treatment focused on replacing or regenerating human cells, tissues and ultimately, organs. This is an evolving field which represents a marked shift in medicine: the idea that it is possible to heal and restore function to damaged tissues and organs that previously were considered untreatable or were treatable via surgery and/or extensive medical procedures. In addition, it is hoped that Regenerative medicine will eventually eliminate the often overwhelming demand for organs available for transplant, which will then alleviate the serious issues of dealing with potential organ rejection created when a successful transplant actually takes place.

The human body is made up of many different types of cells, and most cells are specialized to perform particular functions: such as heart muscle cells, or brain cells or bone cells or blood cells. Red blood cells supply oxygen to all the tissues of the body and remove carbon dioxide from the tissue and take it back to the lungs. Stem cells, however, are basically the body’s raw materials: they are the cells from which all other cells with specialized functions are created. Stem cells, derived from a number of different sources, and stem cell therapy, are the main focus of today’s Regenerative medicine movement.

Under the right conditions, stem cells divide to form more cells, referred to as “daughter cells.” Daughter cells either become new stem cells or they become specialized cells with a more specific function. Stem cell reproduction provides new cells for the body as it grows, and replace specialized cells that are damaged or lost. Stem cells have two unique properties that enable them to do this: They can divide over and over again to produce new cells; and as they divide, they can differentiate and change into other types of cells that make up the body. No other cell in the body has the ability to generate new cell types.

There are three main types of stem cell: embryonic stem cells, adult stem cells and induced pluripotent stem cells.

Embryonic stem cells are stem cells derived from the undifferentiated inner mass cells of the earliest stages of a human embryo, called the embryonic blastocyst. Embryonic stem cells supply new cells for an embryo as it grows and eventually develops into a baby. These stem cells are said to be pluripotent, which means they can grow, or “differentiate” into any type of cell in the body.

Adult stem cells supply new cells as an organism grows and replace cells that get damaged. These stem cells are said to be multipotent, which means they can only differentiate into some cells in the body, not any cell, for example:  Blood (or ‘haematopoietic’) stem cells can only replace the various types of cells in the blood.  Skin (or ‘epithelial’) stem cells provide the different types of cells that make up our skin and hair.

Induced pluripotent stem cells (‘iPS cells’) are stem cells that scientists create in the laboratory by taking normal adult cells, generally skin or blood cells, and reprogram them back into an embryonic-like state to become stem cells. Reprogramming happens when scientists “switch on” the signaling genes that tell a stem cell to remain in its embryo state, and “switch off” genes that signal the cells to become specialized. Just like embryonic stem cells, they are pluripotent so they can develop into any cell type, enabling the development of an unlimited source of any type of human cell needed for therapeutic purposes. Eventually, induced pluripotent stem cells generated from a patient in need of an organ transplant could be used to grow new organs that would have a lower risk of being rejected, since the immune system would not be alerted to the presence of foreign tissue.

Stem cells are used in research for a wide range of applications. They are used to help researchers understand the basic biology of how living bodies grow and develop, and how cells become specialized for specific functions in the body and what happens when this process goes wrong. Scientists are also learning what happens in different types of cells affected by disease and dysfunction, and what might be done within cells themselves to correct or change the course of a disease.

Researchers are continually expanding and developing ways of using stem cells to replace cells or tissues that have been damaged. In addition, in understanding the characteristics of stem cells and their development, scientists are working to replicate this process to create new stem cells and make it possible to create all new tissues and organs. A benefit of this research is that lab-developed tissue and organ structures grown from stem cells can be studied to find out how they function and how they are affected by different therapies and drugs. In the future, scientists hope to be able to actually replace diseased or injured tissue and organs with healthy lab-grown replacements.

A great deal of Regenerative medicine research is concerned with cells, tissues and organs that have been permanently damaged by disease, injury and genetic conditions.  Various types of stem cells are being used to generate new cells and tissue that can then be transplanted into the body to replace those that are damaged or lost. Skin stem cells, for example, are being used to generate new skin for people with severe burns.

Adult stem cells have been used for years to treat some conditions. For instance, hematopoietic (blood) stem cells can be used to create all types of blood cells and platelets and are used to provide a source of healthy blood cells for people with some blood conditions, as well as cancer patients who have lost their own blood stem cells during treatment.

Currently, there is research on stem cell therapy for age-related macular degeneration (AMD). This disease often develops because retinal pigment epithelium (RPE) cells stop working. Scientists are using induced pluripotent stem cells (iPSC) to produce new RPE cells in the lab which can replace the damaged cells.

Some of the newest and most exciting breakthroughs in Regenerative Medicine are happening with the tissue that would be considered the “by-products” after the birth of a healthy baby. Rather than using embryonic stem cells and dealing with ethical considerations and consequences, researchers and doctors are using the placenta, the umbilical cord, and the amniotic fetal membrane as a source of cells. The tissues themselves and the cells are used in research as well as in the Regenerative medicine therapies that already exist.

Regenerative medicine is the new frontier of medicine.  The FDA refers to the products created and used here as “Human cell and tissue based products and therapies” (HCT/Ps); it considers this field to be so broad, so complex, and to have so much potential, that there is a continual shift in the regulations that affect the creation and use of stem cell treatments and medicines. As Regenerative medicine products and treatments become more and more prevalent in the healthcare industry, understanding how they repair tissue and provide therapeutic benefit, AND how they are used properly and safely is a vital concern. Ariel Medical is on the forefront of this new frontier, working only with labs that are in compliance with the FDA, and offering the safest and most effective Regenerative medicine available.