Botany NOU Presentation

STEM CELL THERAPY: 

STEM CELL THERAPY Presented by: Hiranyamayee Panda SEM-III P.G. Dept. of Botany NOU

Contents: 

Contents Definition Types of stem cell Properties Application of stem cells Safety concern Stem cells and diseases

Stem cells : 

Stem cells Rare Primitive cells Defined by their capacity to self renew as well as differentiate into one or more mature cell types .

Types of Stem cell: 

Types of Stem cell Three broad types seen: embryonic stem cells adult stem cells Fetal stem cells

Embyronic stem cell: 

Embyronic stem cell Derived from the inner cell mass Pluripotent Can develop into more than 200 different cells Differentiate into cells of the 3 germ cell layers Because of their capacity of unlimited expansion and pluripotency – useful in regenerative medicine

Tissue or adult stem cells: 

Tissue or adult stem cells They produce cells specific to the tissue in which they are found They are relatively unspecialized However they are predetermined to give rise to specific cell types when they differentiate Eg: haematopoietic, bone marrow, neural

Fetal stem cells: 

Fetal stem cells Haematopoietic stem cell: charecterised by the presence of CD 34 - Seen in the umbilical cord and fetal liver - Have a higher cloning efficiency and generates more progenitors than adult bone marrow. - They have a huge competitive engraftment advantage relative to the adult bone marrow. - Fetal liver is now used to treat fetuses with chromosomal abnormality.

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Haematopoietic stem cells used in patients whose haematopoietic system has to be replaced They are used in 1.Providing a functional immune system 2.Replacing a defective blood system with a functional one who has non malignant genetic disorder like sickle cell anaemia and thallasemia. 3.Restoring the haematopoietic system in cancer patients after treatment.

Properties : 

Properties Self renewal - the ability to go through numerous cycles of cell division while maintaining the undifferentiated state. Potency – the capacity to differentiate into specialized cell types.

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Totipotent stem cells -cells produced by the first few divisions of the cell . So can form any cell of the embryo as well as the placenta.

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Pluripotent – these cells differentiate into cells derived from the three germ cell layers. Eg: embryonic stem cell, embryonic germ cell and embryonic carcinoma cells.

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Multipotent – these cells can produce cells of a closely related family of cells. Eg: haematopoeitic stem cells, neural and mesenchymal stem cells

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Unipotent – these cells only produce one cell type., but have the property of self renewal which distinguishes them from the non stem cells.

Application of stem cells: 

Application of stem cells Stem cell research: 1. It provides an ideal model for the study of development of organisms 2. It replaces damaged cells of the body 3. It also aids in drug discovery

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Regenerative medicine and Therapeutic issues

Therapeutic applications of embryonal stem cells –ES cell: 

Therapeutic applications of embryonal stem cells –ES cell The potential to form 200 or more cells. Hence used in regenerative medicine in cases like cardiac failure, Parkinsons disease, diabetes. These cells are being coaxed to differentiate into cardiomyocytes, neural stem cells, insulin producing cell and even germ cells.

Safety concern: 

Safety concern Potential to form teratomas after transplantation Hence to produce pure differentiated cells. Risk of transfer of xenopathogens

Immunological barriers: 

Immunological barriers Rejection- mediated by class 1 MHC and by antigen presenting cells harbouring the class 2 MHC antigen ES cells are used as models for developmental biology like early embryonic differentiation and understanding the pathogenesis of specific genetic diseases.

Stem cells and diseases: 

Stem cells and diseases The best studied stem cells are the haematopoietic and the male germ cells. Some of the prominent diseases treated include leukemia, anaemia, thallesemia and myelodysplastic syndrome. Allogenic BMT is another well known procedure done.

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Transplantation can be Autologous Syngeneic Allogenic GVHD is least when there is genetic identity.

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Other fetal cells are Mesenchymal stem cells- differentiate to bone, fat and cartilage like the adult counterpart. Neural stem cell- they differentiate into neurons, astrocytes and oligodendrocytes. They are the main source of cells for degenerative CNS injury for replacement. Eg: parkinson’s disease

Potential application of fetal stem cells: 

Potential application of fetal stem cells In the field of fetal medicine: Non invasive prenatal diagnosis Intrauterine stem cell transplantation Gene therapy

Umbilical cord blood stem cells: 

Umbilical cord blood stem cells It has both mesenchymal blood cell and haematopoietic stem cells. 1 st successful umbilical cord blood transplantation in 1989 in a patient with Fanconi’s anaemia.

Haematopoeitic stem cells: 

Haematopoeitic stem cells Derived from bone marrow in adults and umbilical cord blood

Advantages over bone marrow cells: 

Advantages over bone marrow cells High rate of engraftment More tolerant to tissue matches Less severe GVHD Rarely contaminated with latent virus Easy to collect, not painful Superior proliferative capacity Greater immunological naievity Unlimited supply Lower cost

Ailments for which stem cells are being used now: 

Ailments for which stem cells are being used now Acute leukemias Chronic leukemias Myelodysplastic syndromes Marrow failure Myeloproliferative disorders Lymphoproliferative disorders

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Phagocyte disorders Inherited disorders like Lesch Nyhan syndrome, beta Thallesemia etc Inherited platelet abnormalities

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Histocytic disorders Inherited erythrocyte abnormalities Plasma cell disorder Malignancies like neuroblastoma , Ewing sarcoma, Renal cell CA etc

Trials underway: 

Trials underway Cardiac disease Diabetes Multiple Sclerosis Muscular Dystrophy Parkinson’s disease Spinal cord injury Stroke

Future stem cell application: 

Future stem cell application Alzheimer’s Disease Lupus Rheumatoid arthritis

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Research is going on regarding the use of stem cells for male infertility in mouse However the progeny has severe abnormalities

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Also recent research suggests that oocyte can be generated from stem cells originating from Bone marrow- haematopoietic stem cells Ovarian surface cells

Ethical issues: 

Ethical issues Are we trying to play GOD? Is embryo a person? Will stem cell research encourage embryo destruction and abortions?

Guidelines for stem cell research in India: 

Guidelines for stem cell research in India Compulsory registration of the existing cell lines to be registered under specific apex bodies in the field Genetic research dealing with human egg or sperm and genetic engineering and then transfer of human blastocysts will not be allowed

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Research and therapy using fetal/placental stem cell will be allowed Termination of pregnancy cannot be sought for donating fetal tissue for therapeutic or financial benefits

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All the umbilical cord blood banks should be registered with Drug Controller General of India Research into human cloning is not to be done

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These guidelines are aimed to encourage development of sound research and therapy, prevent any misuse of human embryos and fetuses and protect patients from fraudulent treatments in the name of stem cell research.

References : 

References Cell & Molecular Biology: P.K. Gupta www.prize4life.org/ www.like cell .cn www.en.wikipedia.org/wiki/ Stem _ cell www.icmr.nic.in/ stem _ cell / stem _ cell _guidelines.pdf www.authorstream.com/k.man

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