Stem Cell (1-4)
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What type of stem cells are capable of giving rise to all cell types except for those of the placenta?

  • Pluripotent stem cells (correct)
  • Totipotent stem cells
  • Multipotent stem cells
  • Unipotent stem cells

    • Which type of stem cells were first isolated at the University of Wisconsin in 1998?

  • Adult stem cells
  • Embryonic stem cells (correct)
  • Induced pluripotent stem cells
  • Multipotent stem cells

    • What is a major disadvantage of embryonic stem cells?

  • They require many steps to coax into desired cell types. (correct)
  • They are difficult to extract from mature tissues.
  • They cannot produce an endless number of cells.
  • They can only be derived from healthy embryos.

    • Which statement about adult stem cells is true?

    <p>They have limited longevity in culture.</p> Signup and view all the answers

    What advantage does somatic cell nuclear transfer (SCNT) offer for stem cell research?

    <p>It eliminates immune rejection problems.</p> Signup and view all the answers

    What is the primary characteristic of stem cells?

    <p>They can divide indefinitely and become specialized cells.</p> Signup and view all the answers

    Which of the following processes describes how cells become specialized?

    <p>Differentiation</p> Signup and view all the answers

    Which human clinical need is NOT mentioned as requiring stem cell therapies?

    <p>Breast cancer</p> Signup and view all the answers

    What happens to the regenerative ability of an organism as its complexity increases?

    <p>Regenerative ability decreases.</p> Signup and view all the answers

    During which stage of development do cardiac muscle cells and neurons differentiate?

    <p>Embryonic development</p> Signup and view all the answers

    What is the term for transferring cells from one culture dish to another?

    <p>Passaging</p> Signup and view all the answers

    What type of regenerative ability does the planarian exhibit?

    <p>High regenerative ability</p> Signup and view all the answers

    Which of the following best describes adult stem cells?

    <p>They produce specialized cells with decreasing potential.</p> Signup and view all the answers

    What is the main characteristic of epimorphic regeneration?

    <p>It requires the presence of blastema for reconstruction.</p> Signup and view all the answers

    What type of cells are primarily responsible for regeneration in planaria?

    <p>Neoblast cells</p> Signup and view all the answers

    Which type of regeneration is characterized by the regeneration of new individuals from body pieces?

    <p>Morpholaxis</p> Signup and view all the answers

    In vertebrates, which of the following structures is primarily formed during the regeneration of the tail in amphibians?

    <p>Ependymal lining</p> Signup and view all the answers

    What distinguishes morpholaxis from other types of regeneration?

    <p>It reorganizes existing body structures.</p> Signup and view all the answers

    Which type of regeneration occurs after total or partial amputation of an organ?

    <p>Epimorphosis</p> Signup and view all the answers

    Which animal is mentioned as an example of morpholactic regeneration?

    <p>Hydra</p> Signup and view all the answers

    What is a key feature of the regenerated tail in reptiles, such as lizards?

    <p>It is considered an imperfect tail.</p> Signup and view all the answers

    What is the main advantage of using umbilical cord stem cells over bone marrow stem cells?

    <p>They are easier to collect and pose no risk to the donor.</p> Signup and view all the answers

    Which of the following is NOT one of the important functions of umbilical cord stem cells?

    <p>Replication</p> Signup and view all the answers

    What is the percentage of serious Graft versus Host Disease (GVHD) occurrence in unrelated bone marrow transplants?

    <p>60%</p> Signup and view all the answers

    What does the term 'homing' refer to in the context of umbilical cord stem cells?

    <p>The movement to the site of tissue damage.</p> Signup and view all the answers

    How do umbilical cord stem cells compare to fetal lymphocytes in terms of HLA compatibility?

    <p>They have greater HLA compatibility.</p> Signup and view all the answers

    What is the main reason for lower incidence of Graft versus Host Disease (GVHD) in umbilical cord blood transplants?

    <p>Absence of antibodies in stem cells.</p> Signup and view all the answers

    Which type of stem cell is primarily isolated from umbilical cord blood?

    <p>Haematopoietic stem cells</p> Signup and view all the answers

    What does somatic cell nuclear transfer (SCNT) mainly involve?

    <p>Removal of the donor nucleus.</p> Signup and view all the answers

    Which type of regeneration involves the dedifferentiation of adult structures to form an undifferentiated mass of cells?

    <p>Epimorphosis</p> Signup and view all the answers

    What is the term used to describe the regeneration of a different organ from the one that was removed?

    <p>Heteromorphosis</p> Signup and view all the answers

    During which stage of limb regeneration does the bulge known as blastema form?

    <p>Blastema formation</p> Signup and view all the answers

    In which type of regeneration do additional heads develop after a deep incision in organisms like planaria?

    <p>Super regeneration</p> Signup and view all the answers

    Which of the following best describes morphallaxis in regeneration?

    <p>Regeneration from a small body fragment</p> Signup and view all the answers

    What is the final stage of limb regeneration in salamanders called?

    <p>Growth</p> Signup and view all the answers

    What happens to cells in the regeneration bud during epimorphosis?

    <p>They dedifferentiate and proliferate</p> Signup and view all the answers

    What characterizes the regeneration mechanism in shrimp, specifically Palinurus?

    <p>Antennas develop instead of eyes after optic ganglion removal</p> Signup and view all the answers

    What can be regenerated from a small fragment in hydra or planaria?

    <p>A whole individual organism</p> Signup and view all the answers

    Which type of regeneration is characterized by significant new growth and development?

    <p>Epimorphosis</p> Signup and view all the answers

    In which group of animals is regeneration power most prominent in the larval stages?

    <p>Amphibians</p> Signup and view all the answers

    What kind of regeneration ability do lizards exhibit?

    <p>Regeneration of the tail through autotomy</p> Signup and view all the answers

    Which of the following is true about the regeneration capabilities of mammals?

    <p>Regeneration is limited to certain tissues only</p> Signup and view all the answers

    Which group of animals typically exhibits the highest regenerative capability, particularly in the liver?

    <p>Mammals</p> Signup and view all the answers

    What form of regeneration involves remodeling of existing tissues with little new growth?

    <p>Morphallaxis</p> Signup and view all the answers

    Which of the following is NOT true regarding the regeneration process in various animal groups?

    <p>Earthworms can regenerate their entire body</p> Signup and view all the answers

    Study Notes

    Education & Work Experience of Dr. Shamsul Azlin Bin Ahmad Shamsuddin

    • 1987-1989: A.S.A.S.I. sains
    • 1989-1993: BSc Zoology
    • 1993-1997: MPhil, UM
    • 1997-2000: Embryologist, Pantai Bangsar Medical Centre
    • 2000-2003: Embryologist, Gleaneagles, Ampang Medical Centre
    • 2003-2006: Embryologist, Damansara Specialist Hospital
    • Oct 2006- June 2011: PhD, Sheffield University, UK
    • 1997: Embryologist training, Melbourne, Australia (2 months)
    • 2000: Embryologist training, Cairns, Queensland, Australia (2 weeks)
    • 2003: Embryologist training, NUS, Singapore (3 days)

    Embryologist Locums

    • Sime Darby Medical Centre, Subang Jaya
    • Metro Hospital, Kelang
    • Gleaneagles, Penang
    • Darul Ehsan Medical Centre, Shah Alam
    • Mahkota Medical Centre, Melaka
    • LPPKN, KL
    • Columbia Asia Hospital, Setapak, KL
    • Prince Court Hospital, KL

    Regeneration in Nature

    • Planarian
    • Crayfish
    • Embryos

    Inverse Relationship

    • Increase complexity
    • Decrease regenerative ability

    Regeneration in Humans

    • High: Skin, Liver, Muscles, Gut Lining
    • Moderate: Bone
    • Low: Heart, Brain, Joints (Knee)

    Clinical Needs for Stem Cells in Humans

    • Cardiovascular: Myocardial infarction, Stroke
    • Bone: Non-union fractures, Tumor resections
    • Nervous: Spinal Cord Injury, Degenerative diseases

    Definitions of Stem Cells and Differentiation

    • Stem cells: Undifferentiated cells that divide indefinitely in culture (self-renew) to become specialized cells
    • Differentiation: The process where cells become specialized
    • Stem cells with decreasing potential (Adult stem cell): No longer capable of cell division
      • Cardiac muscle cells, Neurons produced during embryonic development, differentiate, and retained through life

    Cell Differentiation Diagram

    • Pluripotent stem cell (Embryonic stem cell)
    • Multipotent stem cells (Adult stem cell)
    • Differentiated cells (muscle, nerve, skin, fibroblast, etc.)

    Types of Stem Cells

    • Embryonic Stem (ES) Cells
    • Embryonic Germ Cells
    • Adult Stem Cells
    • Umbilical Cord-Blood Stem Cells
    • Somatic Cell Nuclear Transfer (SCNT)
    • Induced-Pluripotent Stem (iPS) Cells

    Embryonic Stem Cells Details

    • Embryos are from in vitro fertilization (IVF)
    • Cells are taken from the Inner Cell Mass (ICM) of a blastocyst.
    • ICM cells are nourished in a petri dish in an incubator.
    • Cells are given different types of factors/chemicals to differentiate.
    • These cells can give rise to most types of cells.
    • Human embryonic stem cell lines were first derived in 1998 by Dr. James Thompson.

    Stem Cell Capacity

    • Embryo
    • Inner cell mass
    • Broad capacity

    Somatic Cell Nuclear Transfer (SCNT)

    • Creates clones for reproductive and therapeutic reasons.
    • The diagram shows the removal of the donor nucleus from a somatic cell for the schematic purposes (In general, the whole donor cell is usually transferred).

    Induced Pluripotent Stem Cells (iPSCs)

    • Mature somatic cells were genetically engineered by viruses to achieve pluripotency (ES-like state) in 2007
    • Forced expression of genes helped reprogram adult mouse/human cells into pluripotency
    • Strategies were developed to deliver genes (e.g., non-integrating viruses, chemicals, small molecules) to prevent harmful changes
    • This method allows for patient-specific cell therapies avoiding immune rejection after transplantation

    Stem Cells Research in Malaysia

    • Haematopoietic stem cells (UKM)
    • Mesenchymal stem cells (IMR & UMMC)
    • Tooth pulp stem cells (Dental, UMMC)
    • Bone marrow stromal stem cells (also known as mesenchymal stem cells or skeletal stem cells)

    Cord Blood versus Bone Marrow

    • Cord Blood: Collection non-invasive, painless, no donor risk. Greater HLA compatibility due to decrease fetal lymphocyte functionality. Graft versus Host Disease (GVHD) reduced to 10% due to the absence of antibodies in the stem cells. Units are processed and ready for transplant. Significantly less expensive.
    • Bone Marrow: Collection is invasive, painful. Must be performed in a hospital surgical setting. Stem cell maturity requires a greater HLA match to perform a transplant. Serious GVHD occurs in 60% of all unrelated Bone Marrow transplants. Bone Marrow is donor-dependent.

    Stem Cell Capacity Chart

    • Embryo (Broad)
    • Fetus
    • Adult Organism (Limited)

    Epigenetics Summary

    • Epigenetics literally means "above" or "on top of" genetics.
    • It refers to external modifications to DNA that turn genes "on" or "off".
    • These modifications do not change the DNA sequence.
    • They affect how the cells "read" the genes.
    • Heritable changes in gene expression (active versus inactive genes) that do not involve changes to the underlying DNA sequence: a change in phenotype without a change in genotype. -Epigenetic change is a regular and natural occurrence but can also be influenced by factors like age, environment/lifestyle,and disease state.
    • Epigenetic modifications can manifest in many ways, such as terminal differentiation of cells into skin, liver, and brain cells.

    Mechanisms of Epigenetics

    • DNA Methylation
    • Histone Modification
    • Non-coding RNA (ncRNA) associated genes

    Terminology of Potential (Plasticity)

    • Totipotent
    • Pluripotent
    • Multipotent
    • Unipotent

    What makes stem cells pluripotent?

    • Receptors on their surface that make them responsive to signals from their environment (the niche)
    • Low levels of gene expression for cell types, (e.g., bone, fat, muscle, cartilage).
    • Genes packaged into active and inactive segments
      • Active genes: open configuration (accessible)
      • Inactive genes: closed configurations (inaccessible)
    • Inactive genes with the potential for activation (open configuration but with a brake on)

    Early Development

    • Signals come from within cells and neighboring cells.
    • Maternal nutrition is important for fetal development.
    • Maternal stress hormones can affect the fetus.

    After Birth and Continuing Life

    • Variety of environmental factors shape the epigenome.
    • Social interactions, activity, and diet generate signals that travel throughout the body.
    • Signals within the body are important for many processes including growth and learning.
    • Hormonal signals trigger puberty-related changes.

    Even Into Old Age

    • Cells continually respond to environmental signals.
    • Environmental signals trigger changes in the epigenome.
    • Cellular signals direct body maintenance processes.
    • Re-establishment of cellular maintenance processes is similar to embryonic development.

    The Epigenome Program

    • Programmed alterations of histone patterns.
    • Starts in egg cells, affecting differentiated skin/liver cells.

    Comparison of Embryonic and Adult Stem Cells

    • Adult Stem Cells: From mature tissues; umbilical cord and placenta
    • Embryonic Stem Cells: From inner cell mass of a blastocyst
    • Multipotent vs Pluripotent and Isolation times
    • Further analysis of human tissue responses

    iPSCs—The Wave of Future

    • iPSCs are regarded as innovative stem cell research.
    • Research on disease models, drug screening, and toxicology testing
    • Generating patient-specific cells, allowing unprecedented access to human biology.
    • Studying development and function of human tissues, and regenerative medicine.

    iPSC Applications

    • Treating Parkinson's Disease via cell replacement therapy.
    • Creating electrically active neurons, for studying and treating neurological disorders.
    • Regenerating beta cells (for diabetes)
    • Creating mouse kidneys, (Hiromitsu Nakuchi)

    iPSC Limitations

    • DNA methylation errors compared to ESC lines.
    • Unable to create viable chimeras.
    • Some factors such as c-Myc are oncogenic.

    iPSC Complications

    • Potential tumor formation due to viral transfection systems.
    • Successful use of adenovirus (Konrad Hochedlinger) for gene delivery to eliminate tumor formation risk.

    Cloning Types

    • Reproductive Cloning: Creating identical individuals
    • Therapeutic Cloning: Cloning embryos for research; never implanted
    • This is used for drug designing, disease modeling and in regenerative medicine.

    Animal Models of Regeneration

    • Hydra: Regenerates every part of the body.
    • Planaria: Contains neoblast cells.
    • Annelids: Formation of blastema (cells under the wound or severed area).

    Regeneration of Vertebrates and Types of Regeneration

    • Fish, amphibians, reptiles can regenerate.
    • Regeneration power is well-marked in urodel amphibians (salamanders, and newts).
    • Lizards exhibit autotomy (detaching the tail for defense).
    • Mammals display regeneration in the liver (compensatory hypertrophy) but external parts are not regenerated. Types include:
    • Epimorphosis, Morphallaxis, Heteromorphosis, and Super-regeneration

    Steps of Regeneration of a Limb in a Newt

    • Wound healing: Migration of epidermal cells from wound edges.
    • Blastema formation: Undifferentiated cells creating a bulge.
    • Redifferentiation and morphogenesis: Developing rudiments (e.g. digits)
    • Growth: Regenerating limb increasing to normal size.

    Growth Factors

    • Epidermal growth factor (EGF), Fibroblast growth factors (FGF), Platelets (Derived growth factors).
    • These act locally to initiate cell mitosis, contributing to wound healing and limb regeneration

    Polarity in Regeneration

    • In organisms such as Hydra and planarians, bodies exhibit distinct polarity.
    • Anterior end regenerates into head, while posterior end regenerates into the tail.

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