Health BiotechnologyStem Cell Therapeutics; Tissue Engineering

LECTURE 21:

Biotechnology; 3 Credit hours

Atta-ur-Rahman School of Applied Biosciences (ASAB)

National University of Sciences and Technology (NUST)

• In vitro fertilization (IVF) is a process by which an egg is fertilized by sperm outside the body

• Those embryos that can't be used clinically are a reliable source for embryonic stem cell derivation

Applications of Human pluripotent stem Cells

• Basic Knowledge of Human Development• Models of Human Disease• Transplantation-Cell Replacement • Drug Development • Organogenesis

Tissue Engineering

Tissue engineering is an emerging interdisciplinary field that applies the principles of biology and engineering to the development of viable substitutes that restore, maintain, or

improve the function of human tissues.

Tissue Engineering

• Tissue Engineering is the study of the growth of new connective tissues, or organs, from cells to produce a fully functional organ for implantation back into the donor host.

• For transplantation, to reduce the rejection it can remain isolated from host tissue

• Hence it’s a substitute for damaged tissues and organs

Cells

SignalsScaffold

Tissue Engineering Requires Three Things

Cells for Tissue Engineering

• Stem Cells• an unspecialized cell that gives rise to

differentiated cellsTwo basic types:

Embryonic – pluripotentialAdult – multipotential

Signals Molecule

• The signals refer to molecular signaling molecules, also known as growth factors

• Tissue inducing compounds such as growth factors can serve as signals to simulate the growth and development of different tissue

• Interleukins• Interferons• Cytotoxins• Colony Stimulating Factors• Growth Factors• Suppressor, Inhibitory Factors

Signals Molecule

• Stimulate or inhibit– Cell proliferation– Differentiation– Migration– Adhesion– Gene expression– Secretion and action of other growth factors

Scaffold

• Isolated cells can be grown on extra cellular matrix, collagen or synthetic polymer

• Cell growth and differentiation in 2D cell culture and 3D organ culture, requires presence of structured environment with which cells can interact

• Tissue along with polymer can be implanted into the patient

• Polymers may either be non-degradable and remain in the patent permanently or disappear over the period of time

Scaffold

• Various textures and materials• Encourage cells to grow• Allow nutrients to permeate• Won’t harm the patient

Tissue Engineering

• Using well designed scaffolds and optimized cell growth, we can create tissues such as:– Skin– Bone– Cartilage– Intestine

• These have been successfully engineered to some extent

More complex organs

• Not very far in development• Complex metabolic functions• Require multiple types of cells and intricate

scaffolds– Liver– Heart– Lung– Kidney

To make a bladder one need a scaffold and

several different type of cells

Tissue Engineering for Polio

• A virus attacks cells in the spinal cord– Signal no longer sent to

muscles in the leg– Muscle wasting occurs

• Stem cell treatment could – encourage new spinal

neurons to grow– help new muscle to grow

Tissue Engineering for Diabetes

• Usually for by-pass operation

Tissue Engineering for Artificial Vessels