Progenitor Cells

Question 1

What are progenitor cells?

Answer 1

They are often confused with adult stem cells, progenitor cells are early descendants of stem cells that can differentiate to form one or more kinds of cells, but CANNOT divide and reproduce indefinitely. A progenitor cell is often more limited than a stem cell in the kinds of cells it can become.

Question 2

What are the advantages of progenitor cells over stem cells? [3]

Answer 2

Less tumorigenicity.
More efficient tissue differentiation.
Autologous approach.

Question 3

What are the disadvantages of progenitor cells? [3]

Answer 3

Less proliferation
Demanding isolation process.
Limited number of differentiation pathways.

Question 4

What is autologous cell therapy approach?

Answer 4

Cells from own body.

Question 5

What are some examples of progenitor cells?

Answer 5

Endothelial progenitor cells (EPC).
Neuronal progenitor cells. 
Epidermal progenitor cells. 
Satellite cells. 
Periosteal cells. 
Pancreatic progenitor cells. 
Blast Cells.

Question 6

How do levels of EPC relate to the progression of atherosclerosis?

Answer 6

Levels decline when CVD risk factors appear in high-risk patients. EPC levels decline with plaque development and progression.

Lower EPCs are markers of high risk for future CVD events.

When CVD events do occur, EPC levels should be increased by bone marrow mobilisation. When this mechanism is perturbed, a worse outcome can be predicted.

Question 7

What are the benefits to using Progenitor cells via an autologous approach in tissue replacement?

Answer 7

No immune response due to patients own cells.

Question 8

Circulating levels of EPCs are considered as biomarkers for _______ and ________ ________ ________.

Answer 8

Circulating EPCs levels are considered as biomarkers for coronary
and peripheral artery disease.

Question 9

EPCs have been effectively used to stimulate ____________ and
________ repair in several experimental
settings.

Answer 9

EPCs have
been effectively used to stimulate angiogenesis and vascular repair in several experimental
settings.

Question 10

What are the two approaches that have been used to isolate EPCS?

Answer 10

a) culture and colony assays and b) selection of subpopulations based on surface markers.

Question 11

All current methods for identifying or quantifying the endothelial lineage potential of circulating cells suffer from what limitation?

Answer 11

None have been shown to reliably predict the behaviour of circulating cells in a relevant in vivo context.

Question 12

What is the controversy regarding EPC?

Answer 12

Some authors believe that bone marrow-derived cells do appear to localise to injured vessels and promote an angiogenic switch. While other authors suggest that these cells do not contribute directly and instead act via paracrine methods.

Question 13

What supports the existence of a separate population of progenitors, the late outgrowth, or endothelial colony forming cell (ECFC)?

Answer 13

Molecular genetic analysis of early outgrowth putative EPC populations suggest that they do have monocyte-like expression patterns - this supports the existence of the discrete sub pop.

Question 14

Early outgrowth cells maintain what other functions similar to monocytes? [3]

Answer 14

High Dil-Ac-LDL
India ink uptake.
Low eNOS expression.

Question 15

CFU-HILL or CACs are also shown to express CD14, what is this?

Answer 15

A Lipopolysaccharide receptor expressed by monocytes but NOT endothelial cells.

Question 16

Endothelial colony forming cells (ECFCs) represent what?

Answer 16

A distinct population that has been found to have the potential to differentiate and promote vessel repair.

ECFCs are now known to be tissue-resident progenitor cells in adults that maintain some vasculogenic ability.

Question 17

Of the three main putative adult EPCs populations, which is involved with in vivo de novo vessel formation?

Answer 17

ECFCs.

NOT Circulating angiogenic cells or CFU-Hill cells.

Question 18

EPCs have variable phenotypic markers used for identification. What is the problem with this?

Answer 18

There are no unique markers for endothelial progenitors that are not shared with other endothelial or hematopoietic cells, which has contributed to the historical controversy surrounding the field.

Question 19

Which of the three main pops of adult putative EPCs does not express CD115?

Answer 19

CFU-Hill: Yes
Cac: Yes
ECFC: NO (and not CD14 either).

Question 20

Which of the three main putative adult EPCs does not express CD14?

Answer 20

ECFC does not express CD115 or CD14

Question 21

Which of the three main putative adult EPCs does not express CD133?

Answer 21

ECFC does not express CD14,

CD115 or CD133.

Question 22

How is the Colony forming unit - Hill isolated and cultured?

Answer 22

CFU-Hill is an early outgrowth formed by plating peripheral blood mononuclear cells onto fibronectin-coated dishes, allowing adhesion and depleting non-adherent cells, and isolating discrete colonies.

Question 23

How is the Circulating angiogenic cell isolated and cultured?

Answer 23

To isolate and culture CACs, culture the peripheral blood mononuclear fraction in supplemented endothelial growth medium, removing the non-adherent cells and isolating the remaining. These cells do not form colonies.

Question 24

How are ECFCs isolated and cultured?

Answer 24

Endothelial colony forming cells are a late outgrowth cell type; that is, they are only isolated after significantly longer culture than CFU-Hill cells. ECFCs are isolated by plating peripheral blood mononuclear fraction on collagen-coated plates, removing non-adherent cells, and culturing for weeks until the emergence of colonies with a distinctive cobblestone morphology. These cells are phenotypically similar to endothelial cells and have been shown to create vessel-like structures in vitro and in vivo.

Question 25

What type of EPC is isolated on collage-coated plates?

Answer 25

Endothelial colony forming cells are a late outgrowth cell type; that is, they are only isolated after significantly longer culture than CFU-Hill cells. ECFCs are isolated by plating peripheral blood mononuclear fraction on collagen-coated plates, removing non-adherent cells, and culturing for weeks until the emergence of colonies with a distinctive cobblestone morphology. These cells are phenotypically similar to endothelial cells and have been shown to create vessel-like structures in vitro and in vivo.

Question 26

What type of EPC has been found to create vessel-like structures in vitro and in vivo?

Answer 26

Endothelial colony forming cells are a late outgrowth cell type; that is, they are only isolated after significantly longer culture than CFU-Hill cells. ECFCs are isolated by plating peripheral blood mononuclear fraction on collagen-coated plates, removing non-adherent cells, and culturing for weeks until the emergence of colonies with a distinctive cobblestone morphology. These cells are phenotypically similar to endothelial cells and have been shown to create vessel-like structures in vitro and in vivo.

Question 27

Which type of EPC has the longest culture time?

Answer 27

Endothelial colony forming cells are a late outgrowth cell type; that is, they are only isolated after significantly longer culture than CFU-Hill cells. ECFCs are isolated by plating peripheral blood mononuclear fraction on collagen-coated plates, removing non-adherent cells, and culturing for weeks until the emergence of colonies with a distinctive cobblestone morphology. These cells are phenotypically similar to endothelial cells and have been shown to create vessel-like structures in vitro and in vivo.

Question 28

CFU-Hill is an ____ outgrowth formed by plating peripheral blood __________ cells onto _________-coated dishes, allowing adhesion and depleting __________ cells, and isolating discrete colonies.

Answer 28

CFU-Hill is an early outgrowth formed by plating peripheral blood mononuclear cells onto fibronectin-coated dishes, allowing adhesion and depleting non-adherent cells, and isolating discrete colonies.

Question 29

To isolate and culture _____, culture the peripheral blood _________ fraction in supplemented endothelial _______ medium, removing the ________ cells and isolating the remaining. These cells _____ form colonies.

Answer 29

To isolate and culture CACs, culture the peripheral blood mononuclear fraction in supplemented endothelial growth medium, removing the non-adherent cells and isolating the remaining. These cells do not form colonies.

Question 30

Endothelial colony forming cells are a _____ outgrowth cell type; that is, they are only isolated after __________ culture than CFU-Hill cells. ECFCs are isolated by plating peripheral blood mononuclear fraction on _______-coated plates, removing _________ cells, and culturing for _______ until the emergence of colonies with a distinctive ________ morphology. These cells are phenotypically similar to _________ cells and have been shown to create ________-like structures in vitro and in vivo.

Answer 30

Endothelial colony forming cells are a late outgrowth cell type; that is, they are only isolated after significantly longer culture than CFU-Hill cells. ECFCs are isolated by plating peripheral blood mononuclear fraction on collagen-coated plates, removing non-adherent cells, and culturing for weeks until the emergence of colonies with a distinctive cobblestone morphology. These cells are phenotypically similar to endothelial cells and have been shown to create vessel-like structures in vitro and in vivo.

Question 31

What role do EPCs play in tumour growth?

Answer 31

Endothelial progenitor cells are likely important in tumour growth and are thought to be critical for metastasis and the angiogenesis. A large amount of research has been done on CFU-Hill bone marrow-derived putative EPCs. Ablation of the endothelial progenitor cells in the bone marrow lead to a significant decrease in tumour growth and vasculature development. This indicates that endothelial progenitor cells present novel therapeutic targets.

Question 32

Ablation of the endothelial progenitor cells in the bone marrow lead to a significant decrease in what in tumour patients?

Answer 32

Tumour growth.

EPC could be a novel therapeutic target.

Question 33

Inhibitor of DNA Binding 1 (ID1) has been used as a marker for EPCs implicated in tumour growth, what has it allowed?

Answer 33

Tracking of EPCs from the bone marrow to the blood to the tumour-stroma and even incorporated in tumour vasculature.

Question 34

Work by Plummer et al. found out what with regard to miRNAs, EPC biology and tumour angiogenesis?

Answer 34

The work by Plummer et al. found that in particular targeting of the miRNAs miR-10b and miR-196b led to significant defects in angiogenesis-mediated tumour growth by decreasing the mobilisation of proangiogenic EPCs to the tumour.

Novel strategy?

Question 35

Targeting of which miRNAs may be a movel strategy of inhibiting tumour growth according to Plummer et al?

Answer 35

The work by Plummer et al. found that in particular targeting of the miRNAs miR-10b and miR-196b led to significant defects in angiogenesis-mediated tumour growth by decreasing the mobilisation of proangiogenic EPCs to the tumour.

Novel strategy?

Question 36

What role do circulating EPCs play in cardiovascular disease?

Answer 36

Higher levels: better outcomes.
Following MI, EPCs are mobilised and are believed to function to restore the lining of blood vessels that have become damaged.

Question 37

What did the TOPCARE-AMI trial study?

Answer 37

The therapeutic effect of infusing ex-vivo expanded bone marrow EPCs and culture enriched EPCs derived from peripheral blood into 20 patients suffering from acute MI.

Question 38

What were the findings of the TOPCARE-AMI study?

Answer 38

After four months, significant enhancements were found in ventricular ejection fraction, cardiac geometry, coronary blood flow reserve and myocardial viability.

Question 39

What role do EPCs play in endometriosis?

Answer 39

In endometriosis, it appears that up to 37% of the microvascular endothelium of the ectopic endometrial tissue originates from endothelial progenitor cells