Introduction Of Stem Cell Therapy
Introduction of Stem Cell TherapyMeifeng Xu, MD, PhDDepartment of Pathology and Laboratory MedicineUniversity of Cincinnati
1Stem Cells
Stem CellsStem cells are the cells that do not havea specific role under the right conditionsin the body.They can renew themselves by dividing,even after they have been inactive for aDaughterlong time. Stem cells divide to formCellsmore cells called daughter cells. Thesedaughter cells become new stem cells(self-renewal).The daughter cells also have the ability to develop into specialized celltypes (terminally differentiated) with a more specific function, such asblood cells, brain cells, heart muscle cells or bone cells. No other cellin the body has the natural ability to generate new cell types.
Differentiation of Stem Cells
Differentiation PotentialTotipotent can differentiate into all possible cell types.These cells are produced from the fusion of an egg andsperm cell, e.g. zygote formed at egg fertilization.Pluripotent are the descendants of totipotent cells and candifferentiate into nearly all cell types, e. g., embryonicstem cells.Multipotent can differentiate into those of a closely relatedfamily of cells, i.e. bone marrow stem cells.Unipotent can produce only their own, but have theproperty of self-renewal, which distinguishes them fromnon-stem cells, e.g., muscle stem cells.
Differentiation PotentialAll cells in the bodyCells of all 3 germ layersBone marrow stem cellsMultipotentMultiple cell types of aclosely related familyCommitted ProgenitorsOnly one cell type
Types of Stem CellsThree types of stem cells may be considered to be usedin stem cell therapy:1) Embryonic stem cells;2) Adult stem cells;3) Induced pluripotent stem (iPS) cells.
Embryonic Stem Cells Embryonic stem (ES) cells come from embryos that arethree to five days old. At this stage, an embryo is called ablastocyst and has about 150 cells. These cells are pluripotent. They can divide into more stemcells or can become any type of cell in the body. Thisversatility allows embryonic stem cells to be used toregenerate or repair diseased tissue and organs.Derivation of ES cells from mouse blastocysts (1981)Human ES cells (Thomson, 1998)Blastocysts produced by in vitro fertilization (IVF)
Embryonic Stem CellsSingle CellCulture (early)Culture (later - colony)
The Nobel Prize in Physiology or Medicine 2007for their discoveries of principles for introducing specific genemodifications in mice by the use of embryonic stem cellsMario R. CapecchiBorn: 6 October 1937,Verona, ItalySir Martin J. EvansBorn: 1 January 1941,Stroud, United KingdomOliver SmithiesBorn: 23 June 1925,Halifax, United Kingdom10
Adverse Effect of ES Cells1.The ES cell controversy is the ethical debate centeredonly with research involving the creation, usage, anddestruction of human embryos.2.The embryos being used in embryonic stem cellresearch come from eggs that were fertilized at in vitrofertilization clinics but never implanted in a woman'suterus.3.The major concern with the possible transplantation ofES cells into patients as therapies is their ability toform tumors including teratoma.
Adult Stem Cells Adult stem cells are undifferentiated cells in most adult tissuesor organs, such as bone marrow or fat tissue. They remain in aquiescent or non-dividing state for years until activated bydisease or tissue injury. They can divide or self-renew to generate a range of cell typesfrom the originating organ to replenish dying cells andregenerate damaged tissues or entire original organ. Most adult stem cells are generally referred to by their tissueorigin, but they can also transdifferentiate into other cell types.For instance, stem cells residing in the bone marrow could giverise to blood cells, but also create bone or heart muscle cells.
Adult (Bone Marrow) Stem CellsSingle cellculture (early)Culture (later)
Sources of Adult Stem Cells1) The bone marrow stroma contain mesenchymal stemcells (MSCs).2) Adipose tissue (lipid cells), which requires extraction byliposuction.3) Blood is drawn from the donor (similar to a blooddonation), passed through a machine that extracts thestem cells.4) In addition, stem cells can also be taken from umbilicalcord blood, amniotic fluid, adult muscle or the dentalpulp of deciduous baby teeth.
Induced Pluripotent Stem (iPS) CellsiPS cells are developed stem cellsfrom other mature cells, usinggenetic"reprogramming"techniques. This new techniquemay allow researchers to usereprogrammed cells instead ofembryonic stem cells. iPS cells aresimilar to natural pluripotent stemcells (e.g., ES cells), such as the expression of certain stemcell genes and proteins, doubling time, embryoid bodyformation, potency of differentiation, and teratomaformation.
Differentiation of iPS Cells16
The Nobel Prize in Physiology or Medicine 2012In 2012, Dr. Yamanaka was awarded theNobel Prize in Physiology or Medicine forhis discovery that adult somatic cells canbe reprogrammed into pluripotent cellsBy introducing the genes for four factors(Oct3/4, Sox2, Klf4, and c-Myc). Heinduced the skin cells of adult mice tobecome like embryonic stem cells, whichhe called induced pluripotent stem (iPS)cells. This iPS cell technology representsan entirely new platform for fundamentalstudies of developmental biology.
Aims of Stem Cell Research Increase understanding of how diseases occur by watchingstem cells mature into cells in bones, heart muscle, nerves,and other organs and tissues. Generate healthy cells to replace diseased cells(regenerative medicine). Stem cells can be guided tobecome specific cells that can be used to replace and/orrepair diseased or damaged tissues in people. Test new drugs for safety and effectiveness. Before usinginvestigational drugs in people, researchers can use sometypes of stem cells to test the drugs for safety and quality.This type of testing will most likely have a direct impact ondrug development.
2Stem Cell TherapyReplacement of damaged cells to regeneratetissues and organs by stem cells or thetherapeutic molecules carried by stem cells.
Stem Cell TherapyTransplantation of bone marrow gives patients with radiationdamage or blood cancers a chance to make new, healthy bloodcells using the donor's bone marrow stem cells.There is a shortage of donor organs but, stem cells differentiationhelps to grow a specific tissue type or organ. For example: in casesof severe burn, when a patient does not have a sufficient amountof undamaged skin for skin graft treatment.If the person has heart disease, the cells could be injected into theheart muscle. The healthy transplanted heart muscle cells couldthen contribute to repairing defective heart muscle.
Stem Cell Therapyhttp://en.wikipedia.org/wiki/Stem cell treatments21
Hematopoietic SC TransplantationHematopoietic stem cells (HSC) transplantation is thetransplantation of multipotent HSC, usually derived from bonemarrow, peripheral blood, or umbilical cord blood. It may beautologous, allogeneic, or syngeneic.It is most often performed for patients with certain cancers ofthe blood or bone marrow, such as multiple myeloma orleukemia.However, HSC transplantation remains a dangerous procedurewith many possible complications, including infection andgraft-versus-host disease. It is only reserved for patients withlife-threatening diseases.1
Source of Stem Cells Autologous Extraction and storage ofstem cells from patient(bone marrow or adiposetissue) Lower risk ofinfection/rejection Allogenic Donor with matching tissuetype Immune systemsuppression therapy Risk of graft-versus-hostdisease (GVHD) & infection23
Source of Stem Cells--Autologous1. Mobilization2. Collection of stemcells3. Procession: topurify andconcentrate thestem cells; orculture cells toreprogram to stemcells4. Cryopreservation5. (Chemotherapy)6. Reinfusion24
Source of Stem Cells -- AutologousStem cells are collected from patient.Mobilization of stem cells: patient will receive injections of amedication that makes an increase in production of stem cells.Stem cells are collected from patient. Several harvesting procedures(between one and five) are usually needed to get enough stem cells.The patient will undergo high doses of chemotherapy or acombination of chemotherapy and radiation therapy to kill thecancer cells and to get rid of the stem cells that are left in bonemarrow.Reinfusion stem cells back to patient. This process is similar tohaving a blood transfusion. Now these bone marrow stem cells canmake new blood cells.25
Source of Stem Cells -- Allogenic1. Collecting stemcells from donor(bone marrow orblood)2. Processing: topurify andconcentrate thestem cells; orreprogram thesecells3. Cryopreservation4. Patient treatment5. Reinfusion26
Source of Stem Cells -- AllogenicStem cells are collected from donor’s bone marrow orbloodstream.Several harvesting procedures (between one and five) are usuallyneeded to get enough stem cells.The patient will undergo high doses of chemotherapy or acombination of chemotherapy and radiation therapy to kill thecancer cells and get rid of the stem cells that are left in bonemarrow.Stem cells collected will be infused to patient. Meanwhile, thepatient will be treated with immune regulators.27
Myocardial RegenerationPatient's heart contains damaged tissue, doctors might be able tostimulate healthy tissue to grow by transplanting laboratory-grownstem cells into the person's heart. This could cause the hearttissue to renew itself.Several clinical trials targeting heart disease have shown that adultstem cell therapy is safe, effective, and equally efficient in treatingold and recent infarcts. Stem cell therapy for treatment ofmyocardial infarction usually makes use of autologous bonemarrow stem cells or iPS cells.Other types of adult stem cells may also be used, such as adiposederived stem cells.28
Expansion of Stem CellsHoover-Plow. et al. Vasc Health Risk Manag. 2012; 8: 99–113.29
Administration of Stem Cells1. Introduce locally2. Administrationthrough IVNiall. et al. J. of Cardiovasc.Trans. Res. 2012; 5:713–2630
Stem Cell Patch31
Effect of Stem Cell TherapyThe effect of stem cells includes: protecting risky cells,replacing lost cells, regenerating damaged tissues ororgans, stimulating growth of new blood vessels torepopulate damaged tissue.Therapy success is highly dependent on: survival oftransplanted cells in the recipient; integration within thetargeted tissue and restoration of function; proliferationand differentiation in a site-specific manner.32
Differentiation of Stem Cells into CMStem cells (MSCs) were GFP (green) and co-cultured withcardiomyocytes (CM, red) for 3 days. MSCs are beating with CM.Contrast (MSC CM)CM (red)MSC (Green)Merge (MSC CM)Li. et al. Cytotherapy. 2011;13:1057-65
Immuno-staining of Co-cultured CellsGreen—stem cells; Red---cardiomyocytesα-actininGFPMerge50 mXu, et al. Circulation 2004;110:2658-6534
Stem Cells Secrete Paracrine FactorsMirotsou, et al., JMCC, 2011; 50:280-9.
Secreted Factors Decrease CM InjuryStem cells secrete cell-protective and angiogenesis factorsinto the immediate extracellular environment.Hypoxia CdMHypoxiaNormoxia(CM cardiomyocyte; CdM conditioned Medium)Yu et al.: Plos One
Capillary-like Tube Formation37
Secreted Factors Increase Tube FormationHUVECsCdMCONHUVECs (labeled withPKH67)CdMNullCdM Conditioned mediumCdMGATA-4Li, et al. AJP. 2010;299:H1772-81
Treatment of Type I Diabetes Another investigation, published in Nature Communications in2016, has suggested that stem cell therapies could be thebasis of personalized diabetes treatment. Researchers have successfully produced insulin-secreting cellsfrom stem cells derived from the skin of people with type 1diabetes. The damaged cells in the type 1 diabetes individuals could bereplaced with new pancreatic beta cells. Some sort of device will be filled with these stem cell-derivedbeta cells and these device will be placed just beneath theskin of patient. In theory, patients with type 1 diabeteswouldn't need insulin shots anymore.39
Clinic Sources of Stem Cell TherapyCell typeAbbreviation OriginBone marrow derived stem cellBMSCBone marrowSkeletal myoblastSMAdult skeletal muscleCardiomyocyte progenitorcell/Cardiac stem cellCMPCAdult or fetal heartEndothelial progenitorcell/endothelial precursor cellEPCBone marrow/peripheralbloodEmbryonic stem cellESCBlastocyst stage embryosInduced pluripotent stem celliPSCAny somatic cell40
3Challenges and Solutions
Current Status of Cell Therapy In recent years, clinics have opened that provide stem celltreatments. Scientists are carrying out most of the current research in miceor a petri dish. Very few stem cell treatments have even reached the earliestphase of a clinical trial. A 2016 study published in Cell Stem Cellcounted 570 of these clinics in the United States alone. Theyoffer stem cell-based therapies for disorders ranging fromsports injuries to cancer. However, stem cell therapies are still mostly theoretical ratherthan evidence-based.42
Limitation of Stem Cell Therapy1. Human clinical trials have shown that the initialimprovement in left ventricular function performanceis not sustained in some patients with myocardialinfarction.2. Several studies have sparked intense debate over theability of stem cells to differentiate into targetphenotypes.3. Poor survival of transplanted stem cells in the acidoticand hypoxic microenvironment of the infarctedmyocardium or damaged tissues is another of themajor challenges.43
Mobilization of Stem Cells1. The damaged cells or tissues release some cytokines orchemokine which can mobilize stem cells to thedamaged area to start repair procession.2. Some cytokines and chemokines can promote stem cellsmobilization.3. Mobilizing stem cells is an optimal way for repairing thetissues or organs which are difficult to directly transplantstem cells.44
Ischemic Injury Mobilizes Stem Cells***N 9N 8N 5N 10N 16N 19N 14N 11*Time of LAD ligation (days)Dai, et al. JMCC 2008;44:607-61745
C-kit /sca-1 cell (%)G-CSF Mobilizes Stem Cells**N 10N 6MIMI SCFN 4N 6MI G-CSF MI G-CSF SCFDai, et al. JMCC 2008;44:607-1746
Release of Extracellular Vesicles (EVs) A growing body of evidence demonstrates that theproduction of EVs is a universal feature of cellular life. The vesicles released by stem cells have a lipid bilayerand contain a cell-specific cargo of proteins, lipids, andgenetic material. These vesicles mediate molecule transfer to neighbouringcells to alert them or to change their behaviour. Vesicles can influence the cells which they encounter viadifferent mechanisms to alter their function andbehaviour.47
Types of EVs
100nmMorphology of ExosomesRed BloodCell)Exosomes are the best characterized class of vesicles49
Exosomes as the Carriers mRNA DNA microRNA ProteinEnzymesGrowth roteinsExosomes carry specificproteins and miRNAs fromtheir parental cell type.Waldenström A , and Ronquist G Circulation Research. 2014;114:315-32450
Exosomes-target Cells InteractionAAActivate cell surface receptorsvia protein and bioactive lipidligandBFuse with the cellularmembrane of the target cellsBCCDirectly phagocytosis byrecipient cellsJ Mol Med (2013) 91:431–437
Nobel Prize in Physiology or Medicine 2013James E. RothmanRandy W. SchekmanThomas C. Südhoffor their discoveries of machinery regulating vesicle traffic, a major transportsystem in our cells.52
Therapeutic Potential of Exosomes1. Exosomes recapitulate regenerating effects of parent stem cells invarious animal models and in preclinical studies.2. Exosomes eliminate many issues associated with the use of wholecells, including the risk of occlusion in microvasculature whensystematic administration, recipient immune response,differentiation into inappropriate cell types, and pro-arrhythmicside effects.3. Exosomes therapeutic potential can be significantly enhanced bypre-conditioning or genetic manipulation of the parent stem cells.4. In addition, exosomes have a unique rigid lipid membrane thatmakes them insensitive to freeze-thaw cycles and resistant tobursting in a hypotonic environment. They may be produced inindustrial quantities.53
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Several clinical trials targeting heart disease have shown that adult stem cell therapy is safe, effective, and equally efficient in treating . Stem cell therapy for treatment of myocardial infarction usually makes use of autologous bone marrow stem cells or iPS cells. Other types of adult stem cells may also be used, such as adipose-derived .
This review offers stem cell scientists, clinicians and patient's useful information and could be used as a starting point for more in -depth analysis of ethical and safety issues related to clinical application of stem cells. Key words: embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, stem cell-based therapy.
use ASC pellet for clinical application. Key Words: Adult stem cell, Mesenchymal stem cell, Regenera-tive medicine, Cell- and tissue-based therapy. Introduction Adipose-derived stem cells (ASCs) are mul-tipotent mesenchymal stem cells (MSCs) whose differentiation potential is similar to that of other MSCs1. They exhibit definitive stem cell char-
can be released to guide neural stem cell (NSC) differentiation in a highly controlled manner. Given the challenges in stem cell behavior control, the developed 808 nm NIR-responsive UCNP-based approach to control stem cell differentiation can represent a new tool for studying single-molecule roles in stem cell and developmental biology.
: a progenitor cell that gives rise to one or . more mesodermal lineages (for example, bone, muscle, fat and chrondrocytes). Pericyte: a vascular mural cell that stabilizes endothelial cells . and may have progenitor cell properties. Stem cell niche: a localized microenvironment that supports stem and progenitor cell maintenance. Vascular stem cell
Occupational Therapy Occupational Therapy Information 29 Occupational Therapy Programs 30 Occupational Therapy Articulation Agreements 31 Occupational Therapy Prerequisites 33 Physical Therapy Physical Therapy Information 35 Physical Therapy Programs and Prerequisites 36 Physical Therapy Articulation Agreements 37 Physical Therapy vs .
stem cells to form the blood cells. Therefore, two essential stem cells lines are present in the bone marrow: one that produces the blood cells (hematopoietic) and another that provides the chemical instructions for this production (BMSC). The hematopoietic stem cell produces daughter stem cells that become the source of the individual cell .
the stem cell population, such as stem cell antigen 1 (Sca 1) [4, 8-10]. In the human prostate, the stem cell is characterized by . progenitor/stem cell in the prostate. Multilineage differentiation . clones were isolated by limiting dilution of passage 24 cells and expanded from 96-well plates to larger dishes prior to freezing aliquots .
Tom Sawyer’s observations of his environment and the people he encounters. In addition, students will make their own observations about key aspects of the novel, and use the novel and the journal writing activity to make observations about their own world and the people they are surrounded by. This unit plan will allow students to examine areas of Missouri, both in Hannibal, and in their own .
