Regenerative Medicine Goal: to grow replacement tissue or organs for patients who have sustained an injury or have a disease that permanently damaged their tissue. How?- from patient’s own cells Benefit?- Reduces the need for donor organs and long term use of immunosuppressant drugs. Veterinary researchers are also studying regenerative medicine for animals.

Regenerative Medicine Activity: Key Vocabulary Luke’s Story~ TED Talks( Dr. Atala) In 2011, there were 28,537 organ transplants in the US. More than 100,000 people in the US are waiting for a transplant. #1 NEED~ kidney Average # of patients who die each day while waiting on a transplant= 18

Even though a patient must take medications for the rest of their life after receiving a transplant- Doctors are searching for a way to heal patients with cell and gene therapies and grow replacement tissue organs from a patients own cells.

Background Science Tissue & Organs: Tissues are groups of similar cells performing a similar functions. Organs are made up of multiple tissues working together to perform a function.

The Extracellular Matrix~ Scaffolding The first step of building replacement organs is to build a scaffold~ fibrous proteins form a strong, resilient scaffold and help organize the cells. ( extracellular matrix) Tissues and organs can decellularize. This means that they can be removed leaving on the matrix. The matrix forms the scaffold for the cells but is not made of living tissue. The matrix then can be used as a scaffold to build a new organ.

Scaffolding Scaffolds can come form deceased human donors or animal organs or they can be built from synthetic biomaterial. These are much more available than human organs suitable for transplant.

Challenges Developing biomaterials to build artificial scaffolding. WHY? Biomaterials have to be non- reactive with the human immune system. Have to be the right texture to signal & grow and orient themselves correctly. Have to be strong enough to last until the new organ creates its own extracellular matrix. Bioprinters- keep cells & different substances separate until placing them exactly where they are needed in the new tissue. 3D printers are being developed to one day build human replacement organs.

Challenges 2. The decellularization of animal tissue is challenging because it is difficult to remove all of the cells without damaging the function of the scaffold. 3. Growing new cells on the scaffold & preparing the tissue or organ for its role within the body. Experimentation with growth factors is leading t improved control of cell proliferation and differentiation.

Stem Cells As multicellular organisms develop from zygotes ( cell formed by joining and egg with sperm) to adults, they must produce differentiated cells capable of all the organism's different tissue and organs.\ The undifferentiated cells that give rise to other types of cells are called Stem Cells. Many different types of stem cells found at different stages of development.

Stem Cells As a zygote begins to grow- it is totipotent. This means that this one cell provides all that it is needed for the body as well as the cells types needed for the extra embryonic tissue ( ex. Placenta) Embryonic stem cells are pluripotent~ meaning they give rise to ALL other the types of cells. Adult stem cells ( somatic stem cells) are undifferentiated cells found in differentiated tissues of children and adults. They are multipotent. These cells create the multiple cell types needed in the tissue they come from, but becaues of epigenetic control( inheritable changes in gene expression) they are no longer pluripotent.

Stem Cells Hematpoietic (blood ) stem cells have been used for years to treat various disorders such as leukemia and lymphoma. In these cases, stem cells from the patient or donor marrow replace diseased bone marrow . Stem cells may help replace diseased tissue either by integrating with tissue and producing new cells or producing growth factors that cause the patients cells to regenerate and repair themselves. (ex. Regrowing skin o burn patient)

Stem Cells A new source of stem cells is human amniotic fluid. Derived from amniocentesis or naturally produced at birth. THEY DO NOT INVOLVE DESTROYING THE EMBRYO. They are multipotent and form all sorts of tissue.

New Bone Tissue Stem cells found in bone respond to electrical signals, physical environment and mechanical signals- including the amount of stress, pulling, compression, and hydrostatic pressure. Ex~ Using the right amount of pulling on these stem cell result in the formation of new bone tissue while greater strain results in scar tissue. Researchers are investigating scaffold characteristics and scaffolds that slowly release medications to speed healing, reduce inflammation, and prevent infection.

Careers in Regenerative Medicine Scientist Molecular Biologist Cell Biologist\ Physiologist Pharmacologist Biomedical engineer Surgeons Veterinarians