Dental Pulp Stem Cells Promote Wound Healing and Muscle Regeneration

Abstract

Stem cells (SC) are unspecialized cells that can self-renew and generate specialized progeny through differentiation. These cells are found in almost all multicellular organisms and are capable of renewing themselves through cell division. Moreover, under certain stimuli, they can differentiate into tissue-specific cells. Therefore, stem cells serve as a reservoir and repair system capable of replacing differentiated cells lost either naturally through apoptosis or as a result of trauma or disease. Consequently, the potential of stem cells to renew and differentiate makes them attractive candidates for regenerative medicine. These basic stem cell properties differ among various sources of stem cells, and they can be classified based on their origin and/or differentiation potential. The capacity to differentiate into specialized cell types and be able to originate a mature cell type is referred to as potency. Stem cells can be classified depending on their differentiation potential. Totipotent stem cells can differentiate into embryonic and extraembryonic cell types; such cells can construct a complete, viable organism. Pluripotent stem cells produce all cells of an organism and have the capacity to form representative tissues of all three germ layers of the developing embryo: ectoderm, mesoderm and endoderm. Multipotent stem cells can self-renew and differentiate only in a closely related family of cells from the same germ layer tissues, while unipotent stem cells exhibit limited development potential, giving rise to only a single cell type. Stem cells can be also classified according to the type of cells. Embryonic Stem Cells (ESC) are cells derived from blastocyst, Adult Stem Cells (ASC) refer to any cell found in a developed organism that has the ability to divide and create another cell like itself or even to create a cell more differentiated than itself, and Induced Pluripotent Stem Cells (iPSC) are reprogrammed somatic cells with pluripotent capabilities. Several types of adult stem cells have been isolated from teeth, including Stem Cells from Human Exfoliated Deciduous Teeth (SHED), Periodontal Ligament Stem Cells (PDLSC), Dental Follicle Precursor Cells (DFPC), Stem Cells from Apical Papilla (SCAP) and Dental Pulp Stem Cells (DPSC). These post-natal populations have mesenquimal-like qualities such as the capacity for self-renewal and the potential to differentiate into multiple tissues including adipose, bone, endothelial and neural-like tissue. Dental Pulp Pluripotent-like Stem Cells (DPPSC) are also isolated from the dental pulp of the third molars, express pluripotency markers, and show embryonic-like behaviour differentiating into tissues of the three embryonic layers. Mesoderm-derived cell types are osteogenic cells, chondrogenic cells, adipogenic cells, skeletal muscle cells, smooth muscle cells, cardiac muscle cells and endothelial cells. To date, there exist two commonly used methods to induce vascular cell differentiation from human pluripotent stem cells: embryoid body (EB) formation and monolayer-directed differentiation. The two major cellular components of blood vessels are Endothelial Cells (EC) and Vascular Smooth Muscle Cells (VSMC). A better understanding of the cellular and molecular mechanisms that control VSMC differentiation is essential to help develop new approaches to both prevent and treat several related diseases. Another important mesoderm-derived tissue for regenerative medicine is skeletal muscle, which is responsible for the voluntary movement of the body. Many diseases that affect the musculature belong to the group of muscular dystrophies (MD). Development of reliable and reproducible in vitro cellular models to study these tissues is needed, yet it has been problematic due to intrinsic peculiarities of them.