Regenerative medicine spans a wide range of disciplines in medicine, biology, engineering, and other areas of scientific research. While there are only a limited number of approved regenerative medicine treatments for patients right now, many potential therapies are in clinical trials, or will be soon. These definitions are intended to help you understand terms you may hear as regenerative medicine becomes a widespread topic of conversation. If you would like a definition to a term you don’t see here, please email email@example.com.
- Embryonic Stem Cells
- Gene Therapy
- Induced Pluripotent Stem Cells
- Institute for Stem Cell and Regenerative Medicine
- Precision Medicine
- Regenerative medicine
- Stem Cells
- Stem Cell Therapy
- Tissue Engineering
Biomaterials is an increasingly sophisticated technology that blends principles of engineering and biology to drive discovery and testing of treatments. The term broadly refers to materials that are created for the purposes of interacting with living cells, tissues, organ, and systems. Biomaterials can be derived from natural sources, like proteins or sugars, or from synthetic substances, like polymers, metals, or plastic. Common applications include studying cells in three-dimensional tissue scaffolds, engineering functional tissue, advancing drug discovery, and serving as “ink” in 3D bioprinting. One popular category of biomaterials, known as hydrogels, are water-based structures with customizable properties to house cells in 3D spaces that mimic conditions in living tissue. Next-generation biomaterials can be modified in real-time to direct how cells function in 3D space.
Embryonic Stem Cells
Embryonic stem cells (ESC) appear in the blastocyst, a structure that appears three to five days after fertilization in humans and contains an inner mass of cells which forms the embryo. Embryonic stem cells are pluripotent, which means they can mature into any cell type in the body (except the placenta). Because embryonic stem cells are indefinitely renewable, and can be grown in labs, they are powerful tools of discovery for regenerative medicine researchers studying human development and disease.
Epigenetics are the changes that occur to an organism’s genetic makeup during its development and its life. These changes, which can be caused by environmental or chemical factors, do not alter an individual’s DNA sequence, but do affect the way cells interpret its genetic code and which proteins its cells manufacture. Diet, lifestyle, exposure to sunlight, and aging are all factors that can cause epigenetic changes. In the field of regenerative medicine, researchers study how epigenetic changes contribute to disease-causing mutations.
Gene therapy is a medical intervention that treats a disease through one of two primary methods: gene transfer or CRISPR gene editing. In gene transfer, a normal copy of a gene is delivered by an activated virus into the targeted tissue to correct a missing or broken gene. In CRISPR gene editing, a chromosome-cutting protein known as CAS9, guided by a piece of RNA that corresponds with the broken stretch of DNA, and a segment of DNA containing the normal gene sequence are inserted into a cell to find and repair a genetic mutation. While gene transfer therapies are primarily available in research settings, including one treatment for a rare muscle disorder developed in part by researchers from the Institute for Stem Cell and Regenerative Medicine, a limited number have been approved for patients outside of trials. It is important to note that neither method of gene therapy is currently used for germline editing, meaning that no changes to an individual’s DNA will be passed onto offspring.
In the nucleus of nearly every human cell, approximately three billion base pairs of nucleotides, spread across 23 pairs of chromosomes, are twisted into double strands of replicable genetic material. This is DNA. Each DNA sequence that contains instructions to make a protein is known as a gene, while a genome is the entire set of an organism’s genetic material. Genomics, in turn, is the detailed study of how all those genes work together to code for all human functioning.
Genomics refers to the detailed study of how an organism’s genes interact with one another and the environment. (Genes are units of DNA that carry the genetic code for at least one protein; the human genome consists of 20,000 – 25,000 genes located on 23 chromosomes.) In the field of regenerative medicine, understanding how gene expression differs among individuals gives researchers important clues about how disease-causing mutations occur and how those mutations can be prevented or repaired.
Induced Pluripotent Stem Cells
Unlike embryonic stem cells, which can only be derived from embryonic tissue, induced pluripotent stem cells can be derived from adult cells that are abundant in skin, urine, and blood. Induced pluripotent stem cells are engineered in labs by resetting adult cells to a stem cell-like state. This gives regenerative medicine researchers an easily accessible and replenishable source of stem cells they can use to study human development, disease onset, and potential therapies. Although induced pluripotent stem cells are not yet used in clinics, this technology also means patients could one day be treated with their own cells.
Institute for Stem Cell and Regenerative Medicine
Founded in 2006, the Institute for Stem Cell and Regenerative Medicine (ISCRM) is the largest multidisciplinary research institute at the University of Washington. The ISCRM research community includes more than 130 labs based in medicine, pathology, engineering, and other departments. Four research cores and 100,000 feet of lab space, located primarily in Seattle’s South Lake Union innovation hub, help to catalyze basic science and translational research focused on root cause treatments for diseases impacting nearly every organ and system in the human body.
Organoids, tools that are part of the field of tissue engineering, are micro-organs grown from stem cells to mimic the structure and functioning of human organs. These 3D models enable scientists to study how diseases begin, how they impact entire organs, and how they respond to different drugs without involving animals or human subjects, offering more human, efficient, and cost-effective approach to drug discovery. Right now, researchers at the Institute for Stem Cell and Regenerative Medicine are using organoids to study kidney diseases, liver disease, and Alzheimer’s disease. In recent years, organoids have even been sent to the International Space Station to study the effects of microgravity on kidneys and hearts.
Precision medicine is a customized approach to disease treatment in which care plans are based on factors like patient genetics, drug sensitivities and resistances, environment, and lifestyle. In the field of regenerative medicine, researchers employ tools like artificial intelligence, machine learning, and high throughput screening to gather data from large numbers of patients, turn that data into patient profiles, and use those profiles to select the most effective combinations of drugs for individual patients. Currently, ISCRM researchers are using precision medicine approaches to help extend the lives of cancer patients.
Regenerative medicine is a branch of translational research that combines principles of biology and engineering to develop therapies for diseases characterized by cell depletion, lost tissue, or damaged organs. The broad aim of regenerative medicine is to engineer, regenerate, or replace tissue using natural growth and repair mechanisms, such as stem cells. Organoids, 3D organ printing, and tissue engineering are examples of biopowered technologies used in regenerative medicine. At the Institute for Stem Cell and Regenerative Medicine researchers are using regenerative medicine approaches to target the root causes of heart, bone, kidney, and liver diseases, Alzheimer’s disease, diabetes, and muscular disorders.
Regeneration is the process by which cells replace old or lost skin, bones, and other tissue, as part of normal maintenance or in response to injury. In humans, some tissues, like skin, bone, and gut, are highly regenerative. Other tissues, like the heart and central nervous system, have little or no regenerative capacity. (Regeneration in many tissues declines over time as stem cell proliferation slows.) At ISCRM, researchers are studying the biological mechanisms of regeneration, mapping genes that code for regeneration, and learning to regulate regeneration to treat osteoporosis, heart disease, retinal diseases, diabetes, and other conditions. Looking farther into the future, ISCRM researchers are also exploring the long-term feasibility of regenerating whole organs or body parts.
There are many types of stem cells. In general, the term stem cell refers to a category of cells that give rise to other cells (like skin, blood, heart, and muscle cells) by replicating and differentiating in response to chemical cues. Totipotent stem cells appear at the earliest stage of development and are the only stem cells which can generate embryonic stem cells and the placenta. Embryonic stem cells, which appear soon after fertilization, are pluripotent, meaning they can become all types of cells that make up an individual organism. Tissue-specific stem cells, sometimes called adult stem cells, are multipotent, meaning they can become various types of cells within a specific tissue or organ. Stem cells enable organisms to develop, grow, and replenish tissue lost to injury, disease, and natural attrition. In regenerative medicine, researchers use stem cells to study diseases, to test drugs in labs without involving humans or animals, and, in limited cases, as treatments in patients.
Stem Cell Therapy
Currently, hematopoietic (blood) stem cell transplants, most commonly used to treat leukemia and other cancers, are the only FDA-approved therapeutic use of stem cells. However, other clinical applications are on the horizon, including a heart regeneration therapy developed at ISCRM (entering clinical trials in 2021). A growing number of for-profit businesses, often referring to themselves as clinics, are making scientifically unsupported claims about the therapeutic qualities of mesenchymal stem cells, a category of cells with little or no proven regenerative potential. The public should use extreme caution when considering out-of-pocket stem cell treatments, which can be expensive, ineffective, and even dangerous.
Tissue engineering, in the field of regenerative medicine, refers to the practice of using a combination of cells and natural or synthetic scaffolding to grow tissue for multiple types of research. Engineered tissue can be derived from pluripotent stem cells or from cells that have already been differentiated into specific types (e.g. kidney cells or heart muscle cells). In a common approach to tissue engineering, scientists provide starter cells with a specially shaped matrix (scaffolding), then use physical, mechanical, or chemical cues to direct the cells to assemble, communicate, or express certain genes. The result is a 2D or 3D construct which allows scientists to study organ and tissue functioning, model diseases, or test potential new drugs without involving humans or animal subjects. At ISCRM, researchers are using tissue engineering platforms, including organoids, to study the biology and pathology of the heart, kidney, brain, eye, and muscle system.