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Stem cell

Stem cells

MohammedAlruby
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Stem cell

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  1. 1 Stem cell Stem cell Prepared by: Prepared by: Dr. Mohammed Alruby Dr. Mohammed Alruby S Stem tem cell cell Dr. Mohammed Dr. Mohammed Alruby Alruby

  2. 2 Stem cell Definition: are undifferentiated biological cell that can differentiate into specialized cells and can divide through mitosis to produce more stem cells. This cells found in multicellular organisms as mammals Types of stem cells: 1-Embryonic stem cells: which are isolated from the inner cell mass of blastocyst 2-Adult stem cells: which found in various tissue cell and somatic cell. 3-Fetal stem cell: located in the organs of the fetuses Properties of stem cells: 1-Self-renew: ability to go through numerous cycles of cell division while maintaining the undifferentiated state. 2-Potency: capacity to differentiate into specialized cell types. There is an attempts to restore facial defects with the patient’s own stem cells that minimize the deficiency such as; 1- donor site morbidity, 2- immune-rejection, 3- pathogen transition, 4- sub- potential repair. Frontal process----------- middle and upper region of the face 2 maxillary process -------2 maxillary process ------- checks and upper portion of the jaws Mandibular process ------- lower aspect of the jaws All these processes are populated from mesenchymal cells that are multipotent and capable of differentiating into: fibroblast, osteoblast, chondrocyte, lipocyte (from fat tissue). Differences between the mesenchymal cells and mesenchymal stem cells (MScs) MScs; is likely the product of a symmetrical division of mesenchymal cell In adults: MScs maintain necessary tissue turn over and with injury or disease differentiate to enable tissue regeneration In many cases: MScs: used to regenerate craniofacial structure in vivo that their prenatal predecessor mesenchymal cells are capable of generating during development. Bio-engineering replacement of TMJ: = to regenerate mandibular condyle, rat or human MScs were first isolated from bone marrow and exposed separately to chondrogenic or osteogenic supplemented culture media. = poly-ethylene glycol diacrylate (PEGDA) was dissolved in phosphate buffered saline (PBS) with biocompatible ultra-violet photo initiator. =MScs derived cell were encapsulated in (PEGDA) hydrogel into a negative mold of an adult human cadaver mandibular condyle in two stratified but integrated layers. NB: type X collagen: non fibrillary collagen found primarily differentiated hypertrophic chondrocyte. Type II collagen: basis of articular cartilage and hyaline cartilage forms fibrils which provide tensile strength to the tissues S Stem tem cell cell Dr. Mohammed Dr. Mohammed Alruby Alruby

  3. 3 Dental tissue engineering: 1-Dentine regeneration: cells with properties of adult stem cells have been isolated From dental pulp, exfoliated deciduous teeth and periodontal ligament (PDL). After confirming that dental pulp stem cells differentiate into multiple line ages. Stem cells from human exfoliated deciduous teeth have also been differentiated into odontoblast like cells which in turn produce small dentine like structure. 2-PDL regeneration: isolated stem cells from human PDL have been shown to regenerate cementum / PDL like structure that resemble native PDL as this layer of cementum and interfaced with dense collagen fibers similar to sharpy’s fibers. Bone marrow derived MScs transplanted into periodontal osseous defect are capable of regenerating periodontal tissue in function defect = by repairing periodontal defect, orthodontist and oral surgeon can place temporary anchorage for orthodontic movement and restore missing teeth respectively, also improve bony defect in the mouth will allow orthodontist to position the teeth into sites which it was impossible without regeneration. Cranio-facial bone engineering = stem cell based strategies for craniofacial bone reconstruction may over-come more differences. Adipose derived mesenchymal cells AMcs (that are obtained from abundant adipose tissue) are multipotent and capable of differentiation into muscle, bone, cartilage cells. = AMcs were seeded in apatite-coated poly-acrylic acid and implanted in the surgically created calvarial defect to induce new bone formation similar to bone marrow MScs or osteoblast. = in patient with radiation therapy the irradiation affects bone remodeling and fracture healing Increased apoptosis and xerostomia, so to promote bone formation and this sites, recombinant human bone morphogenetic protein-2 (BMP2) treated hydroxyapatite disks were effective in regenerating bone. = bone formation by transplanted bone marrow stromal cells in enhanced by the concurrent administration of anaerobic doses of parathyroid hormone = salivary gland regeneration has been reported using primary human salivary gland cell to form acinar gland like structure that express amylase. = for the field of orthodontics, possible change may include biologically derived periodontium including single or multiple elements such as: PDL, cementum, alveolar bone, tissue engineered TMJ, cell based bone graft----- used for ---- cleft palate. S Stem tem cell cell Dr. Mohammed Dr. Mohammed Alruby Alruby

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