Guest Scientist Articles

The Stem Cell Era Has Begun

The study of stem cells is beginning to define a new era in medicine and biomedical research. The investigation of these remarkable cells promises potential therapies for numerous diseases and injuries. Stem cells are loosely defined as cells that are able to replicate into many different cell types, while retaining the ability to replenish their own numbers. More precisely, the essential characteristics of a stem cell include the ability to: 1) retain the potential for self-renewal; and 2) sustain the population of at least one functional, differentiated cell type. Numerous sources of stem cells exist.

Human Embryonic Stem Cells

Perhaps the most potentially potent and certainly the most controversial stem cell, human embryonic stem cells (hESCs) are acquired from the inner cell mass of a human blastocyst. These cells have powerful proliferative capacity and can give rise to all cell types from all three germ layers. However, despite these incredible features, therapeutic applications and even progress in basic research using hESCs has been slow to develop due to the heated ethical and political controversy surrounding the inevitable destruction of the human blastocyst that results when the inner cell mass is extracted. Additionally, hESCs have a much less publicized drawback which is that hESCs have shown the propensity to form tumors. This obviously is a huge potential limitation for this cell source to have a great therapeutic impact. Today, the scientific community has come a long way in treatment of cancer but we are not much further along in our knowledge of what forms a tumor in the first place. As such the greatest medical contribution hESCs may provide is an excellent opportunity for scientists to learn more about the natural processes that develop tumors in the human body.

Adult Stem Cells

The study of adult stem cell types skirts the ethical quandary surrounding human embryonic stem cells, and many sources of adult stem cells have been identified, including bone marrow, peripheral blood, adipose tissue, and even periodontal tissue. While many of these stem cell populations are able to differentiate into various cell types, their use is ultimately limited by the requirement for a donor (with an accompanying invasive harvest procedure), immunologic restrictions inherent to transplantation of “non-self” cells, a low capacity for proliferation, and the fact that adult stem cells are extremely rare among differentiated functional adult cells.

Induced Pluripotent Stem Cells

The limitations of other stem cell types have driven innovation in the laboratory through manipulation of cell differentiation. New techniques for producing “stemness” in mature differentiated cells have emerged and include the engineering of the induced pluripotent stem cell (iPSCs). With this method a normal adult fibroblast can be induced to become phenotypically and functionally identical to a human embryonic stem cell in its puripotency. These methods are extremely exciting and may bear invaluable and inexhaustible sources of patient-specific stem cells for many therapeutic purposes. However, these techniques are in their infancy and will require a great deal more knowledge about epigenetic reprogramming, maintenance of pluripotency, and control of stem cell differentiation and self-replication before this technology can be fully harnessed and its clinical potential realized. Currently, like hESCs, iPSCs also form tumors.

Perinatal Stem Cells

Because of the limitations of the stem cell sources outlined above, post-embryonic, perinatal sources of stem cells may yet prove to represent the most important and potentially useful source of stem cells. The term “perinatal” refers to “around the time of birth”, yet technically encompasses the time period from the 20th week of gestation through the neonatal period (the first 28 days of life). Since these tissues are discarded at the time of birth, the harvesting of stem cells from these sources represents a simple, non-invasive and safe means for attaining powerful stem cell types.

This website highlights the characteristics and therapeutic potential of stem cell types obtained from perinatal sources. Sources of perinatal stem cells include umbilical cord blood, the Wharton's Jelly of the umbilical cord, amniotic fluid, the amnion lining the amniotic cavity, the placenta itself- including chorionic mesenchymal stromal cells and multi-potent cells derived from the human term placenta and the endothelial progenitor cells collected from the umbilical cord vein.

Our goal in the establishment of the Perinatal Stem Cell Society is to provide a resource for any scientist or lay person that is interested in learning more about these amazing cells. It is the opinion of the Perinatal Stem Cell Society that collectively, we should begin to save all perinatal tissues and bank the cells collected from these tissues. This website focuses on cells from the amnion, amniotic fluid, cordblood, placenta, umbilical vein and the Wharton’s Jelly.

All of these cells or various combinations of these cells may be used in the future to save lives and enhance the quality of life for many people including to treat one or more of the 80 diseases that have responded to stem cell transplantation. Furthermore, these cells also have the potential to treat degenerative diseases, including heart disease in the adult, orthopedic problems, endocrine disorders such as diabetes, and neurodegenerative diseases such as stroke, Alzheimer’s disease, Parkinson’s disease and spinal cord injuries. The time has to come to focus the perinatal tissues for a non-controversial source of primitive stem cells. Everyone is, or should be interested in stem cells from perinatal tissues.

- Curtis L. Cetrulo, M.D., Curtis L. Cetrulo, Jr., M.D., and Kyle J. Cetrulo