tissue repair regeneration, repair & healing of injured tissues
TRANSCRIPT
Tissue Repair
Regeneration, repair & healing of injured tissues
Repair responses following Injury/Inflammation
Regeneration
Growth of cells and tissues to replace lost structures
Requires an intact connective tissue scaffold
Regulation of cell populations
TYPES OF CELLS
• Labile cells
• Stable cells
• Permanent cells
Labile cells
• have a high rate of loss and replacement and therefore high capacity for regeneration.
• squamous and glandular epithelia
• haemopoeitic cells in bone marrow
Stable cells
• do not normally proliferate but can be stimulated to do so after damage.
• renal tubular cells, • hepatocytes,• osteoblasts, • endothelial cells,• fibroblasts.
Permanent cells
• Permanent cells : unable to divide after initial development and therefore cannot regenerate when some are lost.
• Neurons• Skeletal & cardiac muscle
Cell Cycle
Dolly the sheep, the first clone
Ian Wilmut, who led the team that created Dolly at Scotland's Roslin Institute in 1996
Dolly Parton(singer) after whom the sheep was named
STEM CELLS
Regenerative Medicine
Stem Cells are characterised by their prolonged self renewal capacity and by their asymmetric replication
Embryonic / Adult Stem cells
EMBRYONIC STEM CELLS
Pluripotent cells that give rise to all tissues of the body
To develop Knockout mice
To repopulate damaged organs
Therapeutic Cloning
Stem Cell Research• The Pros
• large potential for finding treatments and cures to a vast array of diseases; cancers; diabetes, spinal cord injuries, Alzheimer's, MS, Huntington's, Parkinson's and many more.
• The use of adult-derived stem cells, from blood, skin and other tissues, has been demonstrated to be effective for treating different diseases in animal models.
• Umbilical cord-derived stem cells have also been isolated and utilized for various experimental treatments.
• The Cons
• The major con to stem-cell research is from the religious stance that life begins at conception and to destroy it to be used for research is immoral and wrong. Currently, the use of embryonic stem cells for research involves the destruction of the blastocysts formed from laboratory-fertilized human eggs.
ADULT STEM CELLS
• More restricted differentiation capacity
• Usually lineage specific
• Located in sites called Niches
• Bone Marrow Haematopoietic stem cells
• Bone Marrow Stromal stem cells
• Transdifferentiation / Developmental plasticity
• Multipotent Adult Progenitor Cells
Stem Cell Niches
Bone marrow stromal cells
Differentiation of embryonic cells and generation of tissue cells by bone marrow precursors
Growth Factors
• Polypeptides
• Some act on many cell types
• Others act on restricted cellular targets
• Cell locomotion, contractility, differentiation, angiogenesis, growth receptors and transcription factors
Signaling mechanisms in Cell Growth
Signal Transduction Pathways
• Receptors with Tyrosine kinase activity
• Receptors lacking Tyrosine kinase activity
• Seven transmembrane G-protein coupled receptors
• Steroid Hormone receptors
Transcription Factors
• C-myc
• C-jun
• C-fos
• p53
ECM and Cell-Matrix interaction