Ms. Rekha Kumari
Asst. Professor, OBG Department (HOD) School of Nursing Science and Research, Sharda University
*Corresponding Author E-mail: rekha.kumari@sharda.ac.in
ABSTRACT:
Stem Cells obtained traditionally were either embryonic in origin or from adult tissue which Included both ethical concerns as well as invasive methods. Stem cells derived from teeth are Simple to obtain and less invasive. In recent times tooth banks have emerged which will be an easy way to store one’s own stem cells. Stem cells can be easily obtained from deciduous teeth and third molars as a result of exfoliation or extraction of impacted teeth. These teeth can be stored for treatment of future diseases by using regenerative procedures. In addition, these cells have minimum risk of rejection. Stem cells from younger teeth have better potential for regeneration. This review will outline the recent trends in stem cells from human teeth and their banking1.
KEYWORDS: Stem cells, tooth banking, regeneration.
INTRODUCTION:
Fig: 1 Stem cell
Stem cells have the unique ability to self-renew or to differentiate into various cell types in response to appropriate signals. These properties provide stem cells with unique capabilities for tissue repair, replacement, and regeneration. Accordingly, human stem cells (fig:1) are of special interest in medical research. Embryonic stem cells have the ability to differentiate into more cell types than adult stem cells.2
It is an undifferentiated cell which is capable of transforming into more cells of same type or multiple other types. They are found in multicellular organisms. They can differentiate into cells of blood, skin, heart, muscles, brain etc. In adult human being, they replenish the dead cells of various organs. Stem cells are being used for treatment of various diseases like diabetes, arthritis, few cancers, bone marrow failure etc3
TYPES OF STEM CELL:
They can develop into any cell type or organ in the body. A single totipotent stem cell can give rise to an entire organism. Fertilized egg or a zygote is the best example. Zygote divides and produces more totipotent cells. After 4 days the cells lose totipotency and become pluripotent.3
Pluripotent Stem Cells:
They can differentiate into any cell type in the human body. Embryonic stem cellsare mostly pluripotent stem cells. They have the ability to differentiate into any of three germ layers: endoderm, mesoderm, or ectoderm.3
These are multipotent stem cells normally found in the bone marrow and are derived from mesenchyme. They differentiate into adipocytes, chondrocytes, osteoblasts, myocytes and tendon. MSCs can also be extracted from blood, fallopian tube, fetal liver and lungs.3
They are the multipotent stem cells derived from mesoderm and located in red bone marrow. They are responsible for production of red blood cells, white blood cells and platelets. HSCs give rise to myeloid lineage (which forms erythrocytes, eosinophils, basophils, neutrophils, macrophages, mast cells and platelets) and lymphoid lineage (which forms T-lymphocytes, plasma cells and NK cells).3
They can differentiate into more than one cell type, but only into a limited number of cell types. Hematopoietic stem cells are considered multipotent as they can differentite into red blood cells, platelets, white blood cells but they cannot differentiate into hepatocytes or brain cells.
Cells with stem cell like abilities have been observed breast cancer, colon cancer, leukemia, melanoma, prostate cancer which can form new cells and lead to tumorigenesis. They cause relapse and metastasis by giving rise to new tumors. Scientists are developing methods to destroy CSCs in place of traditional methods which focus on bulk of cancer cells.3
They are derived from Hematopoietic stem cells. They differentiate into Erythrocyte progenitor cell (forms erythrocytes), Thrombocyte progenitor cell (forms platelets) and Granulocyte-Monocyte progenitor cell (forms monocytes, macrophages, neutrophils, basophils, eosinophils, dendritic cells).3
They are the self-renewing, multipotent stem cells in the nervous system that differentiate into neurons, astrocytes and oligodendrocytes. They repair the nervous system after damage or an injury. They have potential clinical use the management of Parkinson’s disease, Huntington’s disease and multiple sclerosis.3
They are derived from embryo in the blastocyst stage. They are pluripotent stem cells. They give rise to all derivatives of the three primary germ layers: endoderm (stomach, colon, liver, pancreas, intestines etc.), mesoderm (muscle, bone, cartilage, connective tissue, lymphatic system, circulatory system, genitourinary system etc.) and ectoderm (brain, spinal cord, epidermis etc.).3
They are the totipotent, undifferentiated cells present in the meristems (shoot and root apices) of a plant. They never undergo aging process and can grow into any cell in the plant throughout its lifetime. They have numerous applications in production of cosmetics, perfumes, pigments, insecticides and antimicrobials.3
Several types of dental stem cells have been isolated from mature and immature teeth, exfoliated deciduous teeth and apical papilla, MSCS from tooth germs and from human periodontal ligament. They are found to be multipotent and can give rise to osteogenic, adipogenic, myogenic and neurogenic cell lineages.3
Adipose tissue is a huge source of mesenchymal stem cells which differentiate into various cell types. They can be easily extracted in large numbers by a simple lipo-aspiration. They have good application potential in regenerative medicine. ASCs are found to have the ability to differentiate into bone cells, cartilage cells, nerve cells, adipocytes etc.3
Ÿ Tooth Stem Cell Banking
Cord blood (short for umbilical cord blood) is the blood that remains in the umbilical cord and placenta post-delivery. At or near term, there is a maternal–fetal transfer of cells to boost the immune systems of both the mother and baby in preparation for labor. This makes cord blood at the time of delivery a rich source of stem cells and other cells of the immune system. Cord blood banking is the process of collecting the cord blood and extracting and cryogenically freezing its stem cells and other cells of the immune system for potential future medical use.4
As cord blood is inter-related to cord blood banking, it is often a catch-all term used for the4 dental Stem Cell Banking (Tooth Stem Cell Banking) Dental Pulp (fig 2) is the soft tissue inside a tooth. It is the central part of a tooth and is made up of a living tissue which contains powerful mesenchymal stem cells. These have the unique ability to differentiate into many types of cells including bone, heart, cartilage, adipose (fat) and nerve cells, and thus have immense potential to treat various degenerative disorders.5
Fig:2 Dental Pulp
Lifestyle and degenerative disorders are on the rise world over. Conventional treatment methods can only help you manage and not cure them. Dental Stem Cells originate from the neurogenic tissue and can be harvested with ease from a healthy tooth that has fallen out or has been extracted. Thus, they offer multiple chances of collection and the procedure can be performed by your regular dentist.5
Types of Stem Cells in Pulp of Human Teeth:
Adipocytes, chondrocytes, osteoblasts and mesenchymal cells Adipocytes have successfully been used to repair damage to the heart muscle caused by severe heart attack. There is also preliminary data to indicate they can be used to treat cardiovascular disease, spine and orthopedic conditions, congestive heart failure, Crohn's disease, and to be used in plastic surgery.5
Chondrocytes and Osteoblasts have successfully been used to grow bone and cartilage suitable for transplant. They have also been used to grow intact teeth in animals.
Mesenchymal stem cells have successfully been used to repair spinal cord injury and to restore and movement in paralyzed human patients. Since they can form neuronal clusters, they also have the potential to treat neuronal degenerative disorders such as Alzheimer's and Parkinson's diseases.5
Tooth Eligibility Criteria for Banking:
Not all teeth hold the same regenerative potential. The teeth especially primary incisors and canines with no pathology and at least one third of root left contain these unique types of cells in sufficient number. Primary teeth distal to the canine are generally not recommended for sampling. Primary molars have a broader root base, and therefore, are retained in the mouth for a longer period of time than anterior teeth. In some instances, early removal of deciduous molars for orthodontic considerations (e.g. early intervention for space maintenance) will present an opportunity to recover these teeth for stem cell banking.5
Stem Cell Banking- Tooth Collection, Stem Cell Isolation and Storage:
1.Tooth Collection-The tooth exfoliated should have pulp red in color, which is indicative of cell viability. Teeth that becomes very mobile, either through trauma or disease (e.g. Class III or IV mobility), often have a severed blood supply, and are not candidates for stem cell recovery. The tooth is then transferred into the vial containing a hypotonic phosphate buffered saline solution, which provides nutrients and prevent the tissue from drying during transport (up to four teeth in the one vial).
Placing a tooth into this vial at room temperature induces hypothermia. The vial is then carefully sealed and placed into the thermette a temperature phase change carrier, after which the carrier is then placed into an insulated metal transport vessel.
Store-A-Tooth, a company involved in tooth banking uses the Save-A-Tooth device for transporting stem cells from the dental office to the laboratory. The time from harvesting to arrival at the processing storage facility should not exceed 40 hours.5
2. Stem Cell Isolation:
When the tooth bank receives the vial, the following protocol is followed. Tooth surface is cleaned by washing three times with Dulbecco's Phosphate Buffered Saline without Ca++ and Mg++ (PBSA) after which disinfection is done with disinfection reagent such as povidone iodine and again washed with PBSA. The pulp tissue is isolated from the pulp chamber with a sterile small forceps or dental excavator. Stem cell rich pulp can also be flushed out with salt water from the center of the tooth. Contaminated Pulp tissue is placed in a sterile petri dish which was washed at least thrice with PBSA. The tissue is then digested with collagenase Type I and Dispase for 1 hour at 37°C. After this isolated cells are passed through a 70 um filter to obtain single cell supensions. Then the cells are cultured in a Mesenchymal Stem Cell Medium (MSC) medium which consists of alpha modified minimal essential medium with 2mM glutamine and supplemented with 15% fetal bovine serum (FBS),0.1Mm L- ascorbic acid phosphate, 100U/ml penicillin and 100ug/ml streptomycin at 37°C and 5% CO2 in air. Usually isolated colonies are visible after 24 hrs. Different cell lines can be obtained such as odontogenic, adipogenic and neural by making changes in the MSC medium5
3. Stem Cell Storage- Cryopreservation and Magnetic Freezing:
A) Cryopreservation is the process of preserving cells or whole tissues by cooling them to sub-zero temperatures. At these freezing temperatures, biological activity is stopped, as are any cellular processes that lead to cell death. Cells harvested near end of log phase growth are best for cryopreservation. The cells are preserved in liquid nitrogen vapor at a temperature of less than-150°C. This preserves the cells and maintains their potency. In a vial, 1-2x 106 cells in 1.5 ml of freezing medium is optimum. Ice injury is a major concern for tissue cryopreservation.
Suggested that the slow and rate-controlling freezing reduced the ice injury of cryopreserved living cells. studied the differentiation and morpho-functional properties of cells derived from stem cells after long-term cryopreservation to evaluate their potential for long-term storage with a view to subsequent use in therapy. They concluded that dental pulp stem cells and their osteoblast-derived cells can be long-term cryopreserved and may prove beneficial for clinical applications.
To prevent cell damage verification can be utilized, which freezes cells quickly before ice crystals can form, is an efficient approach used to cryopreserve oocytes and embryos. 5
B) Magnetic freezing is the Cell Alive System (CAS). Under the condition of CAS magnetic field energy, water clusters do not accumulate but remain in smaller groups, thus minimizing restraining the expansion of the water. This technology, is called CAS and uses the phenomena that applying even a weak magnetic field to water or cell tissue will lower the freezing point of that body by up to 6-7 degrees Celsius. Once the object is uniformly chilled, the magnetic field is turned off and the object snap freezes. The Hiroshima University company is the first expression of this new technology. Using CAS, Hiroshima University claims that it can increase the cell survival rate in teeth to as high as 83%. This compared to 63% for liquid nitrogen (-196 degrees C), 45% for ultra-cold freezing (-80 degrees C), and just 21.5% for a household freezer (-20 degrees C). Maintaining a CAS system is a lot cheaper than cryogenics and more reliable as well.5
CONCLUSION:
Stem cell therapy is emerging as a revolutionary treatment modality to treat diseases and injury, with wide-ranging medical benefits. SHED are stem cells found in the exfoliated deciduous/ primary teeth of children. Recent studies show that they appear to have the ability to develop into more types of body tissue than other types of stem cells. This difference opens the door to more therapeutic applications. The existing research has clearly shown that primary teeth are a better source for stem cells. While the promise of the immense scope and magnitude that stem cell therapies will have upon the population will only be fully realized in the future, Dental Professionals have realized that the critical time to act is now. The available opportunities to bank their patients' dental stem cells will have the greatest future impact if seized while patients are young and healthy.
REFERENCES:
1. Research gate. [internet][cited 30 July 2014]; available from: http://www.factsforlifeglobal.org/02/https://www.researchgate.net/publication/264314801_REVIEW_ARTCLE_Tooth_Stem_Cell_Banking-A_Review
2. Merck KGaA, darstandth.[internet][cited 2018] ;available from: https://www.sigmaaldrich.com/life-science/stem-cell-biology.html/?utm_source=Google&utm_medium=cpc&utm_campaign=CellBio%20-% 20Stem %20Cells&utm_content=Stem%20Cell%20Homepage&gclid=EAIaIQobChMIkPWnoq2J2wIVkY2PCh0TFAyHEAAYASAAEgIO__D_BwE
4. Cryocell international. Cord blood banking ; available from: https://www.cryo-cell.com/cord-blood-banking
5. Reelabs Internet] available from:http://www.reelabs.com/stem-cell-banking/dental-stem-cell-banking.html
Received on 16.05.2018 Modified on 18.07.2018
Accepted on 10.08.2018 © A&V Publications all right reserved
Int. J. Nur. Edu. and Research. 2018; 6(4):443-446.
DOI: 10.5958/2454-2660.2018.00107.2