Year : 2016 | Volume
: 6 | Issue : 2 | Page : 73--75
Harvesting Mesenchymal Stem Cells for Dental Tissue Regeneration
Dinta Kathiriya1, R Murali2, Madhusudan Krishna3, Krupali Kakkad4, Parthkumar A Thakkar1,
1 Department of Public Health Dentistry, Karnavati School of Dentistry, Gandhinagar, Gujarat, India
2 Department of Public Health Dentistry, Krishnadevraya College of Dental Sciences, Bengaluru, Karnataka, India
3 Department of Public Health Dentistry, Narsinhbhai Patel Dental College and Hospital, Visnagar, Gujarat, India
4 Department of Orthodontics, Tamil Nadu Government Dental College, Chennai, Tamil Nadu, India
Department of Public Health Dentistry, Karnavati School of Dentistry, Gandhinagar, Gujarat
In the present day, stem cell (SC) research has grown exponentially due to the identification that SC-based therapies have the aptitude to improve the life of patients who are suffering from Alzheimer's disease to cardiac ischaemia and in regenerative medicine i.e. bone or tooth loss. Based on the potential to rescue and/or repair traumatised tissue and restore organ function, various varieties of SCs are being investigated. Different human dental SCs are rich with mesenchymal SCs appropriate for tissue engineering. These SCs can be isolated and grown under distinct tissue culture conditions and are useful in tissue engineering. Summarising the high proliferation rates and the multipotency and accessibility makes the dental SC an excellent resource for tissue regeneration. The present review explains findings in the field of dental SC research and on their potential application in the tissue regeneration.
|How to cite this article:|
Kathiriya D, Murali R, Krishna M, Kakkad K, Thakkar PA. Harvesting Mesenchymal Stem Cells for Dental Tissue Regeneration.Adv Hum Biol 2016;6:73-75
|How to cite this URL:|
Kathiriya D, Murali R, Krishna M, Kakkad K, Thakkar PA. Harvesting Mesenchymal Stem Cells for Dental Tissue Regeneration. Adv Hum Biol [serial online] 2016 [cited 2020 May 28 ];6:73-75
Available from: http://www.aihbonline.com/text.asp?2016/6/2/73/190318
Almost all tissues of the human body undergo physiological renewal. Renewing tissues are capable of repairing damage due to disease or injury. Therapeutic modalities, which are currently available, have taken benefit of this phenomenon and incorporated tissue engineering, in which biologic materials are in use to replace, repair and/or improve tissue function. The tissue engineering targets to intensify the body to regenerate tissue by itself and also to grow tissue externally which can then be implanted as natural tissue. In the new millennium, where biotechnology has replaced chemistry, we are here to explore biological solutions. As a result of astonishing advances taking place in the field of cellular and molecular biology, we are offering biological solutions to health promotion, diagnosis, treatment and prognosis.
Reconstructive medicine is advancing by leaps and bounds. It involves the greatest involvement of human mind along with equilibrium where the trend of lengthening life by means of the smallest element of life i.e. a cell, stem cell (SC) is looked into. SCs are undifferentiated cells efficient of self-renewal and conversion into a variety of functional cell types. The discovery of dental SCs and advancement in cellular and molecular biology have influenced the expansion of novel therapeutic strategies that target regeneration of oral tissues, injured by disease or damage. This paper reviews SC bases, properties, characteristics, current research and their potential applications.
SC is the most fascinating area of biology today. The significant characteristics of SCs that differentiate them from other types of cells are being unspecialised cells they renew themselves for extended periods through cell division and also under physiologic or experimental conditions and they can be stimulated to turn into cells with unique functions such as the beating cells of the heart muscle or the cells which produce insulin in pancreas. When injury occurs, a SC self-renews, goes through cell division and produces one daughter SC and one progenitor cell. The progenitor cell is a transitional cell type produced prior to achieve a completely differentiated state.
Types of Stem Cells
There are primarily two types of SCs based on their origin, namely, embryonic SCs (ESCs) and adult SCs (ASCs)/somatic SCs.
Derivatives of embryo i.e. ESCs that are 2–11 days old are called blastocysts. They grow from supernumerary embryos acquired from in vitro fertilisation centres. ESCs were first isolated from mouse embryos in 1981. The success of this work gave rise to the derivation of human ESCs from in vitro fertilised human blastocysts in 1998. They are totipotent cells essentially capable of differentiating into any type of cell including the germ cell. ESCs are regarded as immortal as they can be propagated and preserved in an undifferentiated condition indefinitely. They have the highest capability to regenerate and repair diseased tissue in the body.
Ethical considerations associated with ESCs are as follows: The process of its extraction of SCs from an embryo destroys the embryo itself, thereby raising moral and ethical concerns. Further drawback lies in the likelihood of neoplastic changes if the proliferation and differentiation of these cells are not carefully controlled. While research is going on to overcome a few of these shortcomings as of now, ESCs are not yet used therapeutically and have only remained an excellent platform for research.
ASCs are self-renewable, tissue-resident, multipotent cells. They migrate to the area of trauma and differentiate into definite cell types to promote tissue repair. Autologous ASCs influence rational clinical potential for regenerative therapies. The same can be grouped as Mesenchymal Stem Cells (MSCs) which are derived from the mesoderm layer of the foetus and in the adult inhabit in abundant tissues. Haematopoietic Stem Cells are acquired in district to cord blood or peripheral blood., Dental pulp is the tissue of ectomesenchymal and mesenchymal origins, originated from the dental papilla. Numerous ASCs cells have been isolated from dental tissues: Dental follicle, periodontal ligament (PDL), pulp of exfoliated deciduous teeth and apical papilla. The explicit relationship among different SC is still not clear.
Dental pulp stem cells
Dental pulp SCs (DPSCs) were the foremost dental SCs to be isolated. DPSCs are multipotent SCs. The differentiation of DPSCs to a precise cell lineage is influenced by the elements of local environment. The molecules have a significant function while guiding processes that decide the outcome of SCs and control the production of all tissues in the developing embryo. Functionally, DPSCs can stimulate dentin formation which can protect soft dental pulp tissue and also provide pulp with oxygen, nutrition and innervation, hence maintaining the integrity of tooth shape and function. Similarly, these morphogenic molecules play a significant role in physiological or pathological processes of tissue regeneration, for example, wound healing in dental pulp responses to the progression of dentinal caries, injury and cavity preparation. New odontoblasts are enrolled in response to stimuli, at the dentine–pulp interface, and distinguish at the site of trauma to produce atubular reparative dentin – osteodentin. This provides a 'bridge' of mineralised tissue below the damaged tissue to preserve pulp vitality. Growth factors have an important role in signalling reparative procedure in dentin and pulp. Various biological activities of the tooth are conducted by dentine–pulp complex. Numerous studies have shown that DPSCs play a vital role in the dentin–pulp tissue regeneration. DPSCs have advantages for clinical applications that they can be cryopreserved, retaining multipotential differentiation ability.
Stem cells from human exfoliated deciduous teeth
Stem cells from human exfoliated deciduous teeth (SHED) are secular, immature cells in the teeth that can be developed into specialised cell types by a method called 'differentiation'. SHED habits chondrocytes, osteoblasts and MSCs. Odontoblast-like cells are associated with this regenerated dentin structure, which indicates the odontogenic differentiation potential of SHED. On the other hand, SHED does not form a dentin–pulp complex following in vivo transplantation which is suggestive of SHED having different odontogenic differentiation potential than DPSCs. In regard to the osteogenic differentiation potential, it was remarkable to find that SHED, unlike DPSCs, was not capable of differentiating into osteocyte or osteoblast, but could induce the host cells to go through osteogenic differentiation. Due to their higher proliferation rate and their odontogenic and osteogenic differentiation potential, SHED appears to be more immature form than DPSCs.
Periodontal ligament stem cells
PDL unites tooth roots to the adjoining alveolar bone and maintains homeostasis of PDL and cementum, adjunct to transmitting mechanical stresses. Dental follicle cells originate from neural crest obtained from mesenchyme and distinguish into cells that form the PDL and are present in the developing tooth germ prior to root formation. Evidence shows that PDL inhibits cells that can differentiate into either bone-forming cells (osteoblasts) or cementum-forming cells (cementoblasts). The presence of multiple cell types within PDL recommends that this tissue contains progenitor cells which are responsible for the regeneration of periodontal tissue.
Dental follicle precursor cells
Dental follicle, adjoining the dental papilla and enamel organ of the developing tooth germ prior to eruption, is an ectomesenchymal tissue. Precursor cells have been cultivated from human dental follicles of impacted third molars. Like other dental SCs, these cells when released from the tissue following enzymatic absorption, form adherent clonogenic colonies.
Approaches for Selective Isolation of Undifferentiated Stem Cells
A very technique-sensitive procedure, first reported by Gronthos and co-workers in 2000, was used for the identification and isolation of an odontogenic progenitor cells in adult dental pulp.
Scaffolds in tissue engineering
Scaffold which is used to harvest SCs should be substantially porous to assist cell seeding and diffusion of nutrients. Imperative mechanical properties of a scaffold-material are tensile strength and viscoelasticity. Scaffold materials should present with the microenvironment of target tissues to assist in cell growth. Biocompatibility is an essential clinical feature for scaffold selection. Naturally derived scaffold materials such as collagen, agarose and chitosan glycosaminoglycans have the advantage that they are well tolerated and do not cause immunogenic response. On the other hand, a major shortcoming is heterogeneity of the scaffold and the lack of control over the pore size. Scaffolds made of synthetic polymers such as hydroxyapatite/tricalcium phosphate, polymers such as polylactic acid and polyglycolic acid allow for the manipulation of their physicochemical properties such as pore size, degradation proportion and mechanical resistance. They are biocompatible and allow for cell growth and differentiation, which makes them highly suitable for tissue engineering applications.
Potential applications of human stem cells
SC has the potential for the treatment of neuronal degenerative disorders, chronic heart conditions such as chronic ischaemic heart disease and congestive heart failure, paralysis due to spinal cord injury, periodontal disease and to grow replacement teeth and bone.,,,,,,,
Clinical advantage of pulp/dentin regeneration
Uncontrolled inflammation in the pulpal environment and its progress is a significant consideration in utilising the reparative ability of the tooth and its progenitor cells. There is an evidence of the potential of SCs to migrate to the areas of trauma from other niches in unaffected parts of the pulp and to replace damaged cells in response to pulp capping procedures, following reparative dentinogenesis and dentine bridge formation. Regeneration of damaged pulp and dentin tissues can reverse weaken tooth and avoid following more aggressive procedures that trigger more tooth structure loss.
Issues on the regeneration of functional pulp/dentin
Considering the anatomical location of the pulp that is sheathed within the dentin tissue and receives blood supply only from the apical end, determining vascularity could be difficult when the apical opening is <1 mm. The newly structured dentin is known to be fragile than primary dentin. Regenerated dentin through tissue engineering approaches is deficient in highly organised dentinal tubules.
Regeneration of the dental tissues offers an appealing substitute of conventional restorative techniques because the diseased tissue is replaced by natural tissue that forms an essential part of the tooth. SC therapy is one of the most promising fields of tissue engineering because the transplantation of scaffold materials, containing pulp SCs, provides an admirable inductive means to regenerate orofacial tissues.
We have prospect to move restorative dentistry into a new era, utilising the biological action of the dental tissues to assist wound healing and tissue regeneration. Certainly, the current technology moves towards isolation and cryopreservation of dental pulp progenitor cells for the purpose of banking, are now a days feasible and commercially possible.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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