Plastic surgery and regenerative medicine

Regenerative medicine is a growing new field of medicine that is based on the concept that physicians can harness the body's own powers to heal itself rather than relying exclusively on drugs or invasive surgical procedures. The field deals with the process of engineering human cells, tissues or organs to replace, restore or establish normal function. While "regenerative medicine" predominantly includes therapies and devices that use stem cells, the term is also used to describe therapies that use progenitor cells, as well as other cellular products such as platelet-rich plasma (PRP).

While both PRP and progenitor cells are widely used in the clinical setting, stem cells are still in the early clinical trial stages and not commercially available. PRP is used to treat orthopedic injuries and degenerative joint disease. Progenitor cells have been used for many decades in the form of bone marrow transplants.

But stem cells are all the rage now. However, few people are aware that there are different kinds of stem cells and that they can be derived from different tissue sources and with different donor profiles. To help you better understand the stem cell landscape, let's review some basic concepts.

Autologous vs allogeneic

The most basic premise to understand is that stem cell treatments are largely divided into two classes:

• Autologous: Stem cells are from your own body, exclusively for your own use
• Allogeneic: Stem cells come from another person (a donor)

At present, there are clinical trials involving both autologous and allogeneic therapies. These trials include a wide range of disease states (cardiac, neurologic, autoimmune, orthopedic, etc).

Autologous treatments can be performed in the same operative session and the procedure uses your own cells. Your cells are extracted from a tissue and then reinjected back into your body. It is a one-to-one therapy.

Allogeneic therapies use stem cells from another person, who is referred to as the donor. Before these cells can be put into another human, they must undergo extensive testing for diseases, and the cells are usually culture expanded in laboratories to get higher cell counts. Allogeneic therapies are under strict FDA guidelines as these stem cells will eventually scale up to mass production, be put in a bottle and distributed to millions of patients.

Stem cell types

Stem cells are derived from various tissue sources, and each tissue source has different potentials for the cells to differentiate. These tissue sources and the corresponding type of stem cell are as follows:

Embryonic stem cells (ES)

Embryonic stem cells are derived from the embryo of an unborn baby and were first isolated in mouse embryos in 1981. They have been wrapped in controversy from the beginning because of ethical and religious issues. They are currently used mainly for research and understanding how regenerative cells work.

Adult stem cells (ASCs)

Only in recent decades have we begun to understand that stem cells can be found in all our adult tissues. They are called "adult stem cells". They cannot differentiate into every type of cell, like embryonic stem cells, but they can create bone, cartilage and adipose tissue quite readily. The two most familiar sources of adult stem cells are bone marrow (BM) and adipose tissue (AT). More than 2000 clinical trials have been conducted worldwide using the various tissue sources of adult stem cells.

IPS cells (induced pluripotential cells)

IPS cells do not come from embryos but from adult cells. Their genetic code is manipulated so they become "pluripotent," meaning that they can differentiate or become any other type of cell. Because the genetic code of these cells has been altered, many safety questions remain. IPS cells have a higher risk profile than both adult stem cells and embryonic stem cells.

Types of adult stem cells

Adult stem cells can be isolated from bone marrow, adipose tissue, umbilical cord blood, peripheral blood, dental pump and other tissue sources. Recently, a large number of clinical trials have focused on stem cells derived from bone marrow and adipose tissue.

Bone marrow stem cells

The earliest recognized form of adult stem cells in our body was in the bone marrow. They could be used to help heal bone and to replace different cell types in the blood. They could also be used after bone marrow destruction by radiation therapy or chemotherapy. The use of bone marrow stem cells is FDA-approved under certain conditions.

The problem with bone marrow stem cells is that they are hard to extract and not abundant. In order to treat a patient, these cells must be taken to a lab and expanded in culture. The FDA places this therapy in the category of a drug and requires rigorous oversight and testing. Therapies that use culture-expanded bone marrow cells are not yet commercially available.

Adipose-derived stem cells

In 2001, we became aware that our own fat tissue is a very rich source of mesenchymal stem cells (MSCs). The finding was made by a group of researchers and plastic surgeons (Dr. Adam Katz, Dr. William Futrell) from the University of Pittsburgh and was published in Tissue Engineering Journal. This was quite a revelation for the scientific community, as up until that time, adult MSCs were predominantly thought of as a bone marrow product.

Adipose tissue offered distinct advantages over bone marrow tissue. Not only was adipose fat easier to extract than bone marrow, but the stem cell population found in fat tissue was determined to be an order of magnitude more prolific than BM cells. One ounce of fat contains 300-500 times as many mesenchymal stem cells as an ounce of bone marrow. Because of their abundant cell count, most procedures using autologous adipose stem cells do not require that cells be expanded offsite in a lab. This means that most adipose therapies can be performed in the same operative session. This is advantageous compared to most bone marrow therapies because BM cells are typically culture expanded for days in a lab before they can be reinjected back into a patient.

During the past decade, plastic surgeons have developed very safe and convenient ways to remove fat and isolate stem cells. Unfortunately, adipose stem cell therapies are not yet commercially available because the FDA has not approved them. However, there are scores of ongoing clinical trials using adipose stem cells, many of which have already shown safety and efficacy in the treatment of many disease states.

Adipose tissue as a regenerative therapy

While adipose tissue is a definitive source of stem cells, what if you don't need to isolate or separate the stem cells to get their regenerative power?

Plastic surgeons have known for years that fat grafting itself, without extracting the stem cells, has regenerative properties. Dr. Sydney Coleman pioneered safe and predictable techniques for fat grafting and has documented the regenerative effects of fat grafting in different tissues and disease states. In addition, Dr. Gino Rigotti documented that fat grafting can reverse radiation tissue damage, something that was considered incurable until recently. There are currently clinical studies documenting the regenerative effects of fat grafting in areas we did not even suspect, such as autoimmune diseases and degenerative joint disease. Unlike bone marrow tissue, adipose tissue is easy to extract. It is abundant. And it is effective in ways we have only begun to discover.

Plastic surgeons have decades of experience in harvesting adipose tissue and refining processing techniques for adipose tissue. Because of this unique expertise with adipose tissue, they now have the leading role in developing evolving regenerative applications. The future of regenerative medicine is now, and it belongs to plastic surgery!

For more information, including a list of ASPS plastic surgeons in your community, please use our Find a Plastic Surgeon tool.

*Both images come from CosmeticSurg Blog.