Manifestation of Novel Social Challenges of the European Union in the Teaching Material of Medical Biotechnology Master’s Programmes at the University of Pécs and at the University of Debrecen

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Medical Biotechnology Master’s Programmes

at the University of Pécs and at the University of Debrecen

Identification number: TÁMOP-4.1.2-08/1/A-2009-0011

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TISSUE REPAIR (1)

Dr. Judit Pongrácz

Three dimensional tissue cultures and tissue engineering – Lecture 17

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Stem cells in the bone marrow

• Hematopoetic stem cells (HSC)

• Mesenchymal stem cells (MSC)

• „Side population”

• Multipotent adult progenitor cells (MAPC)

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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 cell

Advantages 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

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Germ stem cells

• Pluripotent

• Scarce harvesting source

• May develop embryonic teratoma cells Adult stem cells

Advantages :

• 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 diseases

BM-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. Cryopreservation

Blood or bone marrow is frozen to preserve it

4. Chemotherapy

High dose chemotherapy and/or radiation is given to the patient

General principles of stem cell therapy

2. Processing

Blood or bone marrow is processed in the laboratory to purify and concentrate the stem

cells

1. Collection

Stem cells are collected from the patient’s bone marrow or blood

5. Reinfusion

Thawed stem cells are reinfused into the patient

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Bone repair with stem cells

Baseline G-CSF mobilization

Monocyte

HSPC

Bone

Osteolineage cells Blood

Perivascular cells

G-CSFR G-CSF

VCAM-1 CXCL12

VLA-4 c-kit kitL CXCR4

C3a uPAR Blood

Monocyte

HSPC

Bone

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Cartilage regeneration

Cultured chondrocytes injected under patch

Periosteal patch harvested from tibia Tissue culture of isolated

stem cells in bioreactors

TGF-b

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TISSUE REPAIR (2)

Dr. Judit Pongrácz

Three dimensional tissue cultures and tissue engineering – Lecture 18

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Liver repair

Functions 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.

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Causes of liver failure

Toxic compounds

• Drugs

• Alcohol

• Chemicals

Infectious 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

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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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hepatocytes

Autologous cultured hepatocytes

Patient

Liver damage

Blood or BM

Isolation of Stem Cells Cell seeding/Inoculation

Culture + HGF Cellular differentiation

Hepatocytes

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Human trials

Cases:

• 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 artery Results:

• Mostly well tolerated

• Improvements in Child- Pugh score, albumin, AST, ALP, bilirubin, clotting

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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?