D2 Biomaterials Lecture 10: Regenerative Medicine

What are the two defining abilities of stem cells?

1. Differentiate into other cells

2. Self regenerate

How old does an embryo need to be to extract stem cells?

5 days

Why is extracting stem cells from embryos controversial?

Destroys fetus

What are the three main sources of stem cells?

1. Embryo

2. Fetus

3. Umbilical cord

What is the term for an early embryo 4 or 5 days after egg is fertilized?

Blastocyst

What does the outer layer of blastocysts become?

Placenta

What does the inner layer of blastocysts become?

Fetus

How long does it take for embryos to become fetuses?

8 weeks

Where are stem cells fond in umbilical cords?

Cord blood

Where are dentinogenic progenitors located that allow dentin repair?

Dental pulp

Where are SHED cells found?

Exfoliated teeth

How many SHED cells are found in each exfoliated tooth?

12 - 20

What markers are found with SHED cells?

Osteoblastic/odontoblastic markers

What can periodontal ligament stem cells form?

Periodontal structures

What is the term for being able to differentiate into many different cell types?

Pluripotent

Which three stem cells are pluripotent?

1. Embryonic

2. Fetal

3. Adult

Which stem cells are multipotent?

Umbilical cord

Which treatment are umbilical cord stem cells good for?

Leukemia

What is the term for a tissue or organ that is moved from one location to another within the same individual?

Autograft

What is the advantage of autografts?

Avoid immunologic effects

What is the disadvantage of autografts?

Limited availability

What is the term for a tissue or organ that is moved from one person to another?

Allograft

What treatment are allografts used for?

Vital organ replacement

What is the advantage of freeze dried bone allografts?

No disease transmission

What is the term for a tissue or organ that is moved from one species to another?

Xenograft

What is the advantage of xenografts?

Widely available

What are the two disadvantages of allografts and xenografts?

1. Immuno-rejection

2. Risk of disease

What are the synthetic materials used for tissue repair and regeneration?

Alloplasts

What is the advantage of alloplasts?

Unlimited availability

What are the two disadvantages of alloplasts?

1. Not resorbable

2. Brittle

What two materials are combined with regenerative medicine?

1. Scaffold material

2. Stem cells

What is the ideal stem cell for bone tissue engineering?

Human mesenchymal stem cells

What are the three advantages of human mesenchymal stem cells?

1. Self-renewal

2. Differentiates into osteoblasts

3. No immunogenic ability

Which stem cells were used for mandibular defects?

Human bone marrow-derived mesenchymal stem cells

How were bone marrow and umbilical cord stem cells used for cranial defects?

Make new osteoblasts

What is the main limiting factor in regenerating large bone defects?

Angiogenesis

Do bone marrow stem cells alone or co-cultures stem cells from bone marrow and umbilical cord create more blood vessels?

Co-cultured stem cells

Which three cells were tri-cultured for vascularization of tissue-engineered bone?

1. Cell-derived stem cells

2. Umbilical cord stem cells

3. Pericytes

Which two processes are promoted by tri-culturing stem cells?

1. Angiogenesis

2. Osteogenesis

What are the two potential applications of stem cells for oral maxillofacial surgeons?

1. Craniofacial repairs

2. Orbital fracture