Manifestation of Novel Social Challenges of the European Unionin the Teaching Material ofMedical Biotechnology Master’s Programmesat the University of Pécs and at the University of DebrecenIdentification number: TÁMOP-4.1.2-08/1/A-2009-0011

TISSUE REPAIR (1)

Dr. Judit PongráczThree dimensional tissue cultures and tissue engineering – Lecture 17

Manifestation of Novel Social Challenges of the European Unionin the Teaching Material ofMedical Biotechnology Master’s Programmesat the University of Pécs and at the University of DebrecenIdentification number: TÁMOP-4.1.2-08/1/A-2009-0011

TÁMOP-4.1.2-08/1/A-2009-0011

Stem cells in the bone marrow• Hematopoetic stem cells (HSC)• Mesenchymal stem cells (MSC)• „Side population”• Multipotent adult progenitor cells (MAPC)

TÁMOP-4.1.2-08/1/A-2009-0011

Therapeutic indications for stem cell therapy• Cardiovascular and ischemic diseases• Diabetes • Hematopoietic diseases• Liver diseases • Orthopedics• More than 25 000 hematopoietic SC

transplantations are performed yearly

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Embryonic stem cellAdvantages of Embryonic SC: • Pluripotent• easy to isolate• highly productive in culture• high capacity to integrate into fetal tissue

Disadvantages:• immune rejection• Differentiation into inadequate cell types • tumors induction • Risk of contamination

TÁMOP-4.1.2-08/1/A-2009-0011

Germ stem cellsGerm stem cells • Pluripotent • Scarce harvesting source• May develop embryonic teratoma cells

Adult stem cellsAdvantages :

• Multipotent• Greater differentiation potential • Less likely induce immune rejection reactions• May be stimulated by drugs

Disadvantages :• Scarce and difficult to isolate• Grow slowly, differentiate poorly in culture• Difficult to handle and produce in adequate amounts for transplantation

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Hemopoetic Cell Transplantation (HCT)Diseases treatable with HCT:• Hemopoetic malignancies• Autotransplantation• Allogenic transplantation• Hereditery immunodeficiencies• Aplastic hematologic diseasesBM-derived stem cells were detected in numerous organs after transplantation or injury (sex-mismatched transplantation)

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Hematopoetic stem cells• Stem cell theory emerged in the 50’s• Located in the BM• CD34+, CD133+, c-kit+, CD38-, CD45-• Worldwide databases available of BM donors

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3. CryopreservationBlood or bone marrow is

frozen to preserve it

4. ChemotherapyHigh dose chemotherapy

and/or radiation is given to the patient

General principles of stem cell therapy

2. ProcessingBlood or bone marrow is

processed in the laboratory to purify and concentrate the

stem cells

1. CollectionStem cells are collected from the patient’s bone marrow or

blood

5. ReinfusionThawed stem cells are

reinfused into the patient

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Bone repair with stem cells

Baseline G-CSF mobilization

Monocyte

HSPC

BoneOsteolineage cells

Blood

Perivascularcells

G-CSFR

G-CSF

VCAM-1

CXCL12

VLA-4c-kitkitL

CXCR4

C3auPAR

Blood

Monocyte

HSPC

Bone

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Cartilage regeneration

Cultured chondrocytesinjected under patch

Periosteal patchharvested from tibia

Tissue culture of isolatedstem cells in bioreactors

TGF-b

TISSUE REPAIR (2)

Dr. Judit PongráczThree dimensional tissue cultures and tissue engineering – Lecture 18

Manifestation of Novel Social Challenges of the European Unionin the Teaching Material ofMedical Biotechnology Master’s Programmesat the University of Pécs and at the University of DebrecenIdentification number: TÁMOP-4.1.2-08/1/A-2009-0011

TÁMOP-4.1.2-08/1/A-2009-0011

Liver repairFunctions of the liver:• Metabolism• Energy homeostasis, glycogen production and

storage• Detoxification• Bile production • Plasma protein synthesis

In case of injury the intrinsic repair capacity may be insufficient.

Today the long-term therapeutic option for liver failure is transplantation.

TÁMOP-4.1.2-08/1/A-2009-0011

Causes of liver failureToxic compounds• Drugs• Alcohol• ChemicalsInfectious diseases• Hepatitis viruses• Bacteria• Parasites (malaria)Intrinsic causes• Genetic • Autoimmune (primary biliary cirrhosis)

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Liver transplantation• Today the only long term therapy for liver

failure• Immuno-suppression needed• Patient is prone to infections• Serious side-effects of immunosuppressant

drugs• Worldwide shortage of donors

TÁMOP-4.1.2-08/1/A-2009-0011

Potential in cellular therapy of liver failure• Less invasive than organ transplantation• Can be repeated multiple times• Limiting factor is the inability of

– Producing a sufficiently large number of hepatocytes

– Keep hepatocytes ready for use on-demand• Expansion of existing hepatocytes• Using stem cells to differentiate hepatocytes

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Using stem cells for liver regeneration• BM stem cells• Hematopoetic SC• Mesenchymal SC• Stem/progenitor cells in the liver• Embryonic stem cells

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HSC and liver regeneration• BM resident HSC contains a population

expressing SC markers (CD34, c-kit) and a-fetoprotein (aFP, liver progenitor cell marker)• When BMSC were cultured in the presence

of hepatocyte growth factor (HGF) showed hepatocyte-like characteristics• These experiments were done in rodents

and humans

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MSC and liver regeneration• MSC subpopulation multipotent adult

progenitor cells (MAPC)• Human MAPC differentiated into hepatocyte-

like cells in the presence of HGF• Substantial delay of the differentiation • Therefore the potential of clinical usage is

questionable

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Cultured HSC differentiate into hepatocytes

Autologous cultured hepatocytes Patient

Liver damage

Blood or BM

Isolation of Stem CellsCell seeding/Inoculation

Culture + HGF

Cellular differentiation

Hepatocytes

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Human trialsCases: • Liver cancer • Hepatitis B or C• Cirrhosis (alcoholic,

drug or primer)BMSC: • Unsorted

mononuclear cells • Sorted CD34+ or

CD133+ cells

Route of administration:

• Peripheral vein• Portal vein• Hepatic arteryResults:• Mostly well tolerated• Improvements in

Child-Pugh score, albumin, AST, ALP, bilirubin, clotting

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Injury-induced differentiation of BMSC (animal models)• Murine model: sex-mismatched donor BMSC

transplantation in a hereditary lethal liver disease model (tyrosinemia, FAH-/-)

• 1/3 of the hepatocytes were of donor origin after 22 weeks

• In an induced liver cirrhosis model, 25% of hepatocytes were of donor origin after just 4 weeks

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Conclusions• Clinical application is not well established

and not ready for routine therapy• Which cases?• Which cells?• Which administration route? • Risks and benefits of autologous cellular

therapy in liver failure?