The diversity of cellular life

Colonies of primitive unicellular organisms don’t show emergent properties Prokaryotic organisms or primitive eukaryotic organisms (algae, protistae) exist in colonies of identical cells While the cells co-operate, they do not fuse to form a single mass and so don’t form a single organism Each cell has identical structure and function

Multicellular organisms have differentiated cells Cells are specialised: Blood cells Muscle cells Retinal cells Glandular cells Epithelial cells Each cell type has a special task and structure Each cell has the same DNA, but only a section of it is expressed

Levels of ‘organisation’ in a multicellular organism  CELL  TISSUE  ORGANS  ORGAN SYSTEMS

Cardiac myocytes

Heart

Cardiovascular system

4 key animal tissue types 1. Epithelial 2. Connective 3. Muscle 4. Nervous

Human Anatomy, Larry M. Frolich, Ph.D.

Simple: just one layer or cell shape Stratified: multiple layers and cell shapes Classes of Epithelia

“ciliated” literally = eyelashes (see next page)

Stratified: regenerate from below

CONNECTIVE TISSUES “Areolar tissue” as model Universal in body Underlies epithelium, supports capillaries, small nerves

Cells of Connective Tissues Fibroblasts make fibres – cartilage, ligaments, blood, bone Immune cells in areolar tissue

Different types of Connective tissues Dense Ligaments Cartilage Bone Loose Fat Areolar Human Anatomy, Larry M. Frolich, Ph.D.

Tissue types 3. Muscle tissue Skeletal Cardiac Smooth

Tissue types 3. Nervous tissue Skeletal Cardiac Smooth

Neuroglia

Cell Differentiation Harvard Animation

What are stem cells? Cells that are able to generate more specialised types of cell types through the process of cell differentiation Cells that can divide to make identical copies of themselves, through self-renewal You can learn all about stem cells by watching the beautiful animation from Utah Genetics here: Stem Cells

Different types of stem cells 1. Embryonic Stem Cells Here, you can learn how embryonic stem cells are made: Quck guide to Embryonic stem cells Quck guide to Embryonic stem cells Here is the BBC video on how embryonic stem cells are made: How to make stem cells

Different types of stem cells 2. Somatic Stem Cells (also called adult stem cells) Exist naturally in the body Used for bone marrow transplants Can only differentiate into dedicated cell types

Adult Stem Cells are committed to become one type of cell

Stem cells in the adult brain: Are they still working for us now?

Stem cells in mature skeletal muscle: Is there power still in our stem cells?

Different types of stem cells 3. Induced pluripotential Stem Cells Created artificially in the lab by ‘reprogramming’ a patients own cells Made from patient’s own cells – fat, skin, fibroblasts Can become any cell in the body (even a whole mouse!)

Induced pluripotential Stem Cells – The future! Learn the story of iPS stem cells from Utah Genetics… IPS stem cells

Pros and Cons to iPS cell technology Pros: Cells would be genetically identical to patient or donor of skin cells (no immune rejection!) Do not need to use an embryo Cons: Cells would still have genetic defects One of the pluripotency genes is a cancer gene Viruses might insert genes in places we don’t want them (causing mutations)

Different types of stem cells 4. Therapeutic Cloning: ‘patient- specific embryonic stem cells’ Can theoretically create pluripotent stem cells from patient’s own cells Ethically highly controversial Scientists have not yet grown a cloned human to the blastocyst stage

Different types of stem cells

Stem Cells used in medicine: Treatment of leukaemia Stem cell transplants have been successfully used since 1968 to treat patients with leukaemia Patients with leukaemia first have their own abnormal blood cells destroyed by radiotherapy Then the patients own bone marrow stem cells are replaced with a transplant (into the bloodstream) from a healthy patient’s bone marrow If the transplant is successful, then the stem cells will migrate into the bone marrow and begin to produce new, healthy leucocytes You can learn all about leukaemia treatment by linking here onto Utah Inc: Utah Genetics

Stem Cells used in medicine: Umbilical Cord Blood Umbilical cord blood stem cell transplants have been used for treatment of leukaemia. Unbilical cord blood stem cells are less prone to immune rejection They are considered a potent resource for transplant therapies

Embryonic Stem cells are pluripotent

What can we use Stem Cells for? To provide lab-grown human or animal tissue for identifying new treatments for disease (rather than using animals in research) TO produce new human tissue and organs to replace damaged ones To repair tissue by stimulating stem cells already in the body To use stem cells from patients with inherited genetic diseases (e.g. cystic fibrosis, some forms of Parkinson’s disease) to study the disease To better understand diseases like cancer To investigate human development

Stem Cell Research is a fast- moving subject Stem cell grandparents Brand new sperm First trial of human embryonic stem cells Tracheal transplant Stem cell nobel prize

The Stem Cell Ethical Debate

The Ethical Questions Until recently, the only way to get pluripotent stem cells for research was to remove the inner cell mass of an embryo and put it in a dish. The thought of destroying a human embryo can be unsettling, even if it is only five days old. Stem cell research thus raised difficult questions: Does life begin at fertilization, in the womb, or at birth? Is a human embryo equivalent to a human child? Does a human embryo have any rights? Might the destruction of a single embryo be justified if it provides a cure for a countless number of patients? Since ES cells can grow indefinitely in a dish and can, in theory, still grow into a human being, is the embryo really destroyed?

Ethics and iPS: Problem solved? With iPS cells now available as an alternative to hES cells, the debate over stem cell research is becoming increasingly irrelevant. But ethical questions regarding hES cells may not entirely go away. Inevitably, some human embryos will still be needed for research. iPS cells are not exactly the same as hES cells, and hES cells still provide important controls: they are a gold standard against which the "stemness" of iPS cells is measured. Some experts believe it's wise to continue the study of all stem cell types, since we're not sure yet which one will be the most useful for cell replacement therapies. An additional ethical consideration is that iPS cells have the potential to develop into a human embryo, in effect producing a clone of the donor. Many nations are already prepared for this, having legislation in place that bans human cloning.

Key Ethical Questions (1) MORALITY AND HUMANITY OF EMBRYOS 1. At what point does an embryo/ blastocyst have full moral status? 2. Is there a ‘moral cut-off’ at 14 days after fertilisation? 3. Does an embryo’s moral status increase as it develops?

Key Ethical Questions (2) 1. Is there anything wrong with using spare embryos left over from fertility treatment? 2. Is it morally justifiable to use embryonic stem cells as a means to an end, if they will provide huge benefits from human health? 3. Should we be using embryonic stem cells at all, if we have the alternatives of stem cell lines derived from umbilical cord blood or induced pluripotential stem cells?

Arguments about embryonic cells

Arguments about Somatic Cell Nuclear Transfer

Arguments about the Moral Status of the Embryo (1)

Arguments about the Moral Status of the Embryo (2)

Arguments about the moral status of the embryo (3)

Arguments about the moral status of the embryo (4)

Links on ethics related to Stem Cell research Stem Cell Ethics Factsheet Ethics and Embryos Factsheet Are embryos human? – a conversation…