Surprise: Stem Cells in your Teeth!
By Marc Breyer
Perhaps you have never heard of this, but stem cells can be found in your teeth. I never knew this either until I began translating Dr. Moira Pedroso Leão’s abstracts of two articles she wrote called “Isolation and in vitro characterization of human stem cells”.
We lay people usually have trouble understanding the sort of language used by scientists, and health professionals in general. When language gets too specialized, people who do not belong to that specific field of study have trouble understanding it. Being a translator, and specifically a translator in the field of health sciences, I was recently forced to learn about this fascinating new field of dental stem cells in order to be an effective translator for Dr. Leão.
First, let me provide an introduction to the basic vocabulary of this very specific field of health science. We will need to understand three medical terms: “tissues”, “stem cells”, and “in vitro”.
From Wikipedia, we learn that a “tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning. Organs are then formed by the functional grouping together of multiple tissues”.
From the The National Institutes of Health, here are several relevant pieces of information about stem cells: “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 physiological or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the stomach or in 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”.
Stem cells vary according to their original tissues and whether they are embryonic (found only in embryos); adult (found in basically all human organs); or induced pluripotent (adult stem cells that can be genetically “reprogrammed” in laboratories).
Here’s the definition of “in vitro”: “Latin for ‘in glass’; in a laboratory dish or test tube; an artificial environment”. The term “in vitro” is most commonly heard when discussing “in vitro fertilization”, which is a technique that unites the egg and sperm in a laboratory instead of inside the female body.
Why are stem cells considered so important? Clinical studies have shown that these cells can be transplanted from one person into another, with no need for an immunosuppressant – an agent that can suppress or prevent the immune response. Thus stem cells are frequently introduced during organ transplant surgery to prevent rejection of a transplanted organ. They are also used to treat some autoimmune diseases. Stem cells have the power to differentiate into other cells such as those found in bone tissue or in cartilage, and they do not produce antigenicity, that is, the cells do not cause rejection.
The stem cells found in the dental tissue, more specifically in the pulp of the teeth, are present mainly in exfoliating deciduous teeth (‘milk’ or ‘baby’ teeth that are about to fall out). They can also be found in permanent teeth, in the periodontal ligament and in the apical papilla (soft areas both inside and around the teeth).
Doctor Leão informed me that in the past, dental pulps and periodontal ligaments of extracted teeth have been thrown away. However, because of the efforts of scientists like herself researching the relevance and application of dental stem cells, from now on what was once considered biological waste can be stored for use in research on the value of dental stem cells in the regeneration of damaged tissues.
She is presently working on the creation of a Cell Technology Center (CTC) on stem cells and cell and tissue by-products at Universidade Positivo in Curitiba. The CTC aims to process and store stem cells found in dental tissues.
Interestingly, the current biosafety laws do not apply to the use of dental stem cells, so a committee has been created in order to structure a law that regulates such an important issue.
One of the main study centers on dental stem cells is located at King’s College, London, where researchers supervised by Dr. Paul Sharpe have been working to reach the long-awaited third dentition (we humans only have two dentitions), and to better understand how the mechanism that changes a ‘dental germ’ into an incisor, a molar or a canine works.
For the time being, the practice of manipulating dental stem cells will continue in research labs and will not be occurring in our dental offices and clinics. We will have to wait awhile for this great innovation to be put into practice.
[Moira Pedroso Leão is a doctor of Implantology at Universidade Federal de Santa Catarina (UFSC), a professor at Universidade Positivo (UP) in Curitiba and a member of the Commission for Support and Technical Advice of the Federal Council of Odontology (CFO) Brazil on stem cells and cell and tissue by-products. She may be contacted at: www.curitibabiotech.com.br or firstname.lastname@example.org.]
This article was written in English by Marc Breyer. He is a German-Brazilian writer, translator, and teacher of English in Curitiba. He may be contacted at email@example.com