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STEM CELLS
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Stem cells are mother cells that have the potential to become any type of cell in the body.
• Just like the stem of a plant will produce branches, leaves and flowers, so stem cells can produce many different kinds of cells.• Stem cells are distinctive and versatile type of cells and divide indefinitely• Stem cell possesses two properties: Self renewal and Unlimited potency.• A stem cell is a cell that has the ability to divide for indefinite periods often throughout the life of the organism.• Stem cells are considered to be progenitor of more than 200 cell types
present in adult body.• Stem cells are uncommitted cells until it gets signals to develop into specific
cells.
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PROPERTY OF STEM CELL
Figure :Property of stem cells
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TYPES OF STEM CELLS (BASED ON SOURCE)
1. Embryonic stem cells
2. Adult stem cells
3. Hematopoetic stem cells
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1.Embryonic stem cells
• Embryonated stem cell: Derived from embryos (blastocyst) .
• Embryonic stem cells seem to be more flexible.
• They are also generally easier to collect, purify and maintain in the laboratory than adult stem cells.
• Sources: In vitro fertilization Nuclear transfer
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1. In vitro fertilization:
• Stem cells derived from human embryos created through in vitro fertilization.
• Couples can legally donate their unborn embryonic children to research by signing consent forms.
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2. Nuclear transfer
• It is done by inserting the nucleusof an already differentiated adult cell.
For example, a skin cell—into a donated egg that has had its nucleus removed.
• This egg, which now contains the genetic material of the skin cell is then stimulated to form a blastocyst from which embryonic stem cells can be derived.
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2.Adult stem cells
Adult stem cells are hidden deep within organs, surrounded by millions of ordinary cells.
• Adult stem cells can switch tissues. Adult stem cells migrate throughout the body in the blood.
• We can harvest adult stem cells from the individual to be treated. Therefore, there are no rejection problems.
• Adult stem cells can even be injected intravenously in large quantities and they will migrate to where the injury is located.
• Scientists hope to use this capability to replace cells damaged by a broad spectrum of diseases.
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1. Bone marrow stem (Mammary/Mesenchymal stem cells)
2. Neural stem cells 3. Olfactory adult stem cells (Nose for sense of smell)
4. Adipose derived adult stem cells (Bone, cartilase, fat, muscle etc)
5. Multipotent adult progenitor cells (heterogenous population of stem cells)
Types of adult stem cells (Stem cells appear in adult bone marrow and other tissues)
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3.Hematopoietic Stem Cells
• Hematopoetic stem cells are the blood cells that give rise to all the other bloodcells .
• They are derived from mesoderm.
• They are located in the red bone marrow, and is contained inthe core of most bones.
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Source of Hematopoietic Stem Cells
• Bone Marrow
• Peripheral Blood
• Umbilical Cord/placenta Blood Stem Cells
In 2005, the National Academies issued a report, Cord Blood: Establishing a National Hematopoietic Stem Cell Bank Program, which recommended that a national cord blood “bank” be established to harness the medical potential of this source of stem cells.
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Some examples explaining scope of stem cells in treatment of disease:
1. Type I diabetes (juvenile-onset): It is caused by the loss of the insulin-
producing cells of the pancreas. • Finding a cure for such diseases would be much easier if scientists could simply re-grow the missing or damaged cells and implant them into patients.
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2.Possible Future Treatment for Parkinson’s Disease
• Because Parkinson’s disease results from the loss of one specifictype of nerve cell, stem cells offer a very tangible possibility for treatment.
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Cancer: Getting to the Root of the Problem
• Research into the differences in gene expression between normal and tumor stem cells may lead to treatments where the root of the problem—the cancer stem cell—is targeted.
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Stem cells and regenerative medicine:
• Given their unique regenerative abilities, stem cells offer new potentials for treating diseases such as diabetes, and heart disease.
• Stem cells ca be used for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine.
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Human pleuripotent stem cell culture
• At present, more than 234 hPSC lines have been registered at the National Institutes of Health (NIH), which are eligible for use in federally funded research.
Challenges in Human pleuripotent stem cell culture (i) Lack of standardized protocols for specific applications (ii) An absence of efficient assays to monitor cellular stress
induced during cell processing (iii) Genomic instability related to chromosomal abnormalities (iv) Potential tumorigenicity
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Hurdles of Stem Cell Therapy1. Immune rejection
2. Long Term Sequelae (a pathological condition resulting from a disease, injury, therapy, or other trauma)
Neoplastic Potential (abnormal growth of tissue) : an explosive ability to grow and to change into other types of cells,so test on animal model is pre-requisite.
3. Toxicity
4. Infection
5. Carcinogenecity
6. Mortality
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• Presented By: Sudiksha Chaulagain• M.Sc Biotechnology
• 1st Semester• Roll no:9