Regenerative medicine terms, A to Z

Plain-language definitions of stem cell, PRP, exosome and other regenerative medicine terms, and of the research and FDA words you'll see alongside them.

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Stem cellA stem cell is an unspecialized cell, meaning it has no set job in the body yet. When it divides, it can make more stem cells like itself or cells that mature into one particular type, such as a red blood cell or a nerve cell. This helps the body grow and replace worn-out cells. In the US, only a small number of stem cell products have FDA approval, and nearly all are blood-forming stem cells, many of them from donated umbilical cord blood.
Stem cell therapyIn stem cell therapy, a patient is given stem cells, or cells grown from them, with the goal of treating an illness or helping injured tissue heal. Stem cells can keep copying themselves and can also turn into other, more specialized cells. The best-established type is a blood stem cell transplant (also called a bone marrow transplant), used for some blood cancers and other blood disorders. The FDA has approved only a small number of stem cell products and warns that many sold to the public are unapproved.
Platelet-rich plasma (PRP)Platelet-rich plasma is plasma (the liquid part of blood) with extra platelets packed in. It comes from spinning the person's own blood so it separates into layers. Platelets are tiny cell pieces that help blood clot, and they carry growth factors, proteins that signal cells to grow and repair. A 2024 review of 75 randomized trials (studies that assign groups by chance), mostly on joint, tendon, skin and hair problems, found that studies made and described PRP in very different ways, so results are hard to compare.
ExosomesExosomes, one type of extracellular vesicle, are tiny packets a cell builds inside itself and then pushes out. Each is sealed in a thin fatty skin (a membrane) and averages about 100 nanometers wide (a nanometer is a billionth of a meter). Other cells can take in their contents, including proteins, fats and bits of DNA or RNA, which can change how those cells behave. The FDA says no exosome products are approved and has warned of serious health problems in people given unapproved products sold as exosomes.
Mesenchymal stem cell (MSC, mesenchymal stromal cell)Mesenchymal stem cells (MSCs) are found in bone marrow, fat, the umbilical cord and other tissues. Mesenchymal refers to connective tissue. In the lab, MSCs can turn into bone, cartilage and fat cells, and they release signals that affect the immune system. Experts recommend calling them mesenchymal stromal (support) cells unless tests show true stem cell abilities. In December 2024, the FDA approved its first MSC therapy, for children whose serious immune reaction after a donor blood stem cell transplant did not respond to steroids.
Regenerative medicineRegenerative medicine is an area of medical research and care that aims to rebuild or restore body parts harmed by injury or disease, from single cells up to whole organs. One approach tries to boost the body's natural healing, sometimes by adding cells or growth factors (proteins that signal cells to grow). Another, called tissue engineering, grows new tissue on a support frame known as a scaffold. The FDA regulates these products and has warned that many sold to the public lack its approval.
Peptide therapyPeptides are short chains of amino acids, the small building blocks that make up proteins. Peptide therapy means using peptides as medicine. Most are given as shots, because the stomach and gut break them down if they are swallowed. Insulin, used for diabetes, is a well-known example. The FDA has raised safety concerns about several unapproved peptides proposed for compounding (custom mixing by pharmacies), including BPC-157, citing possible immune reactions, impurities and too little safety information in people.
FDA approvalFDA approval is a decision by the US Food and Drug Administration that a product may be sold for a specific use. Before approving a drug or biologic (a medicine made from living sources, such as cells), FDA scientists study lab, animal and human test results and judge whether the benefits outweigh the risks. FDA does not approve clinics or doctors, and registering with FDA is not approval. Only a few stem cell products are FDA approved, mostly blood-forming cells from donated cord blood, each for specific uses.

All terms, A to Z

A

Adipose-derived stem cells (fat-derived stem cells): Also called ADSCs, ASCs, adipose-derived stromal cells, adipose-derived mesenchymal stromal cells (AD-MSCs), fat-derived stem cells; Create a free account to read this definition.; See alsoMesenchymal stem cell (MSC, mesenchymal stromal cell)Stromal vascular fraction (SVF)Culture-expanded cells Unproven stem cell treatment
Adult stem cell (tissue-specific stem cell): Also called tissue-specific stem cell, somatic stem cell, resident stem cell; Create a free account to read this definition.; See alsoStem cell Multipotent Hematopoietic stem cell (blood-forming stem cell)Mesenchymal stem cell (MSC, mesenchymal stromal cell)
Allogeneic: Also called Allogenic, Allograft, Donor cells; Allogeneic (A-loh-jeh-NAY-ik) means the cells or tissue come from another person, not from the patient (and not from an identical twin). In an allogeneic stem cell transplant, the donor is often a relative or an unrelated volunteer whose tissue type (markers on cells that the immune system checks) matches the patient's closely or partly. Cord blood transplants, which use blood donated from a newborn's umbilical cord, are allogeneic too. A serious risk is graft-versus-host disease, when the donor's immune cells attack the patient's healthy tissues.; See alsoAutologous Stem cell transplant (bone marrow transplant)Cord blood Perinatal tissue (placenta, amniotic membrane and fluid, umbilical cord)
Autologous: Also called Autogenous, Autograft, Self-donated cells; Autologous (aw-TAH-luh-gus) describes a treatment that uses a patient's own cells, tissue or blood rather than a donor's. In some stem cell transplants, for instance, a patient's blood-forming stem cells are collected and frozen before high-dose cancer treatment, then returned to them afterward. Using your own cells does not make a product risk-free. FDA says unapproved products made from a person's own cells still need its approval, and it has received reports of harms, such as infections and blindness, from unapproved products like these.; See alsoAllogeneic Stem cell transplant (bone marrow transplant)Platelet-rich plasma (PRP)Unproven stem cell treatment

B

Bone marrow aspirate concentrate (BMAC): Also called BMAC, bone marrow concentrate, BMC; Create a free account to read this definition.; See alsoMesenchymal stem cell (MSC, mesenchymal stromal cell)Autologous Orthobiologics Platelet-rich plasma (PRP)

C

CAR-T cell therapy: Also called CAR T-cell therapy, chimeric antigen receptor T-cell therapy, CAR T; Create a free account to read this definition.; See alsoGene therapy Autologous Allogeneic FDA approval
Cell viability: Also called Viability, Percent viable cells, Live cell percentage; Create a free account to read this definition.; See alsoCulture-expanded cells Stem cell therapy Investigational New Drug (IND) application
Clinical trial: Also called clinical study, interventional study; A clinical trial is a study where volunteers try a drug, device, procedure or other approach so researchers can learn whether it is safe and helpful. Each trial follows a written plan called a protocol. Drug trials usually run in phases, from small safety studies to larger ones comparing the new approach with a placebo or standard care. In the US, testing an unapproved drug or biologic (a medicine made from living sources, including many cell therapies) in people requires an Investigational New Drug application to the FDA first.; See alsoRandomized controlled trial Placebo Informed consent Investigational New Drug (IND) application
Cord blood: Also called umbilical cord blood, UCB; Create a free account to read this definition.; See alsoHematopoietic stem cell (blood-forming stem cell)Stem cell transplant (bone marrow transplant)FDA approval Perinatal tissue (placenta, amniotic membrane and fluid, umbilical cord)
Culture-expanded cells: Also called Cultured cells, Expanded cells, Lab-grown cells, Passaged cells; Create a free account to read this definition.; See alsoMinimal manipulation and homologous use (HCT/Ps)Mesenchymal stem cell (MSC, mesenchymal stromal cell)Cell viability Investigational New Drug (IND) application

D

Differentiation: Also called cell differentiation, cell specialization; Create a free account to read this definition.; See alsoStem cell Pluripotent Multipotent Growth factors

E

Embryonic stem cell: Also called ESC, human embryonic stem cell (hESC); Create a free account to read this definition.; See alsoPluripotent Induced pluripotent stem cell (iPSC)Clinical trial FDA approval
Exosomes: Also called exosome, small extracellular vesicles; Exosomes, one type of extracellular vesicle, are tiny packets a cell builds inside itself and then pushes out. Each is sealed in a thin fatty skin (a membrane) and averages about 100 nanometers wide (a nanometer is a billionth of a meter). Other cells can take in their contents, including proteins, fats and bits of DNA or RNA, which can change how those cells behave. The FDA says no exosome products are approved and has warned of serious health problems in people given unapproved products sold as exosomes.; See alsoExtracellular vesicles (EVs)Secretome (conditioned media)Mesenchymal stem cell (MSC, mesenchymal stromal cell)Unproven stem cell treatment
Extracellular vesicles (EVs): Also called EVs; Create a free account to read this definition.; See alsoExosomes Secretome (conditioned media)Growth factors FDA approval

F

FDA approval: Also called FDA-approved, Marketing approval; FDA approval is a decision by the US Food and Drug Administration that a product may be sold for a specific use. Before approving a drug or biologic (a medicine made from living sources, such as cells), FDA scientists study lab, animal and human test results and judge whether the benefits outweigh the risks. FDA does not approve clinics or doctors, and registering with FDA is not approval. Only a few stem cell products are FDA approved, mostly blood-forming cells from donated cord blood, each for specific uses.; See alsoInvestigational New Drug (IND) application Clinical trial Minimal manipulation and homologous use (HCT/Ps)Unproven stem cell treatment

G

Gene therapy: Also called Gene transfer, Gene addition, Genetic therapy; Create a free account to read this definition.; See alsoCAR-T cell therapy Clinical trial FDA approval Investigational New Drug (IND) application
Growth factors: Also called growth factor, GFs; Create a free account to read this definition.; See alsoPlatelet-rich plasma (PRP)Secretome (conditioned media)Exosomes Regenerative medicine

H

Hematopoietic stem cell (blood-forming stem cell): Also called HSC, blood-forming stem cell, blood stem cell, hematopoietic progenitor cell; Create a free account to read this definition.; See alsoStem cell transplant (bone marrow transplant)Cord blood Adult stem cell (tissue-specific stem cell)Autologous
Hyaluronic acid injection: Also called Viscosupplementation, Viscosupplement, Intra-articular hyaluronic acid, Hyaluronan injection; Create a free account to read this definition.; See alsoPlatelet-rich plasma (PRP)Orthobiologics Placebo Systematic review and meta-analysis

I

Induced pluripotent stem cell (iPSC): Also called iPSC, iPS cell; Create a free account to read this definition.; See alsoPluripotent Embryonic stem cell Differentiation Clinical trial
Informed consent: Also called Consent form, Patient consent; Informed consent is the process of learning about a medical test, treatment or research study and then freely deciding whether to agree to it. Before you decide, the care or research team should explain why it is offered, what will happen, the possible risks and benefits, and other options, then check that you understand. You can ask questions, ask for the information in a language you know, or say no. In a clinical trial, you can also leave at any time, even after signing the consent form.; See alsoClinical trial Investigational New Drug (IND) application Unproven stem cell treatment
Investigational New Drug (IND) application: Also called IND, IND application; Create a free account to read this definition.; See alsoClinical trial FDA approval Informed consent Unproven stem cell treatment

M

Mesenchymal stem cell (MSC, mesenchymal stromal cell): Also called MSC, mesenchymal stromal cell, multipotent mesenchymal stromal cell; Mesenchymal stem cells (MSCs) are found in bone marrow, fat, the umbilical cord and other tissues. Mesenchymal refers to connective tissue. In the lab, MSCs can turn into bone, cartilage and fat cells, and they release signals that affect the immune system. Experts recommend calling them mesenchymal stromal (support) cells unless tests show true stem cell abilities. In December 2024, the FDA approved its first MSC therapy, for children whose serious immune reaction after a donor blood stem cell transplant did not respond to steroids.; See alsoMultipotent Adipose-derived stem cells (fat-derived stem cells)Wharton's jelly Unproven stem cell treatment
Minimal manipulation and homologous use (HCT/Ps): Also called HCT/P, Homologous use, 361 HCT/P, Human cells, tissues, and cellular and tissue-based products; Create a free account to read this definition.; See alsoFDA approval Investigational New Drug (IND) application Stromal vascular fraction (SVF)Perinatal tissue (placenta, amniotic membrane and fluid, umbilical cord)
Multipotent: Also called multipotency, multipotent stem cell; Create a free account to read this definition.; See alsoPluripotent Adult stem cell (tissue-specific stem cell)Hematopoietic stem cell (blood-forming stem cell)Mesenchymal stem cell (MSC, mesenchymal stromal cell)

O

Orthobiologics: Also called Ortho-biologics, Orthopedic biologics; Create a free account to read this definition.; See alsoPlatelet-rich plasma (PRP)Bone marrow aspirate concentrate (BMAC)Adipose-derived stem cells (fat-derived stem cells)Autologous

P

Peptide therapy: Also called Therapeutic peptides, Peptide drugs, Peptide treatment; Peptides are short chains of amino acids, the small building blocks that make up proteins. Peptide therapy means using peptides as medicine. Most are given as shots, because the stomach and gut break them down if they are swallowed. Insulin, used for diabetes, is a well-known example. The FDA has raised safety concerns about several unapproved peptides proposed for compounding (custom mixing by pharmacies), including BPC-157, citing possible immune reactions, impurities and too little safety information in people.; See alsoFDA approval Clinical trial Regenerative medicine
Perinatal tissue (placenta, amniotic membrane and fluid, umbilical cord): Also called birth tissue, perinatal derivatives, placental tissue; Create a free account to read this definition.; See alsoWharton's jelly Cord blood Allogeneic Minimal manipulation and homologous use (HCT/Ps)
Placebo: Also called sugar pill, dummy treatment, sham treatment; A placebo is a look-alike treatment with nothing in it that should affect the condition being studied, such as a sugar pill or a shot of salt water. In a placebo-controlled trial, one group gets the placebo and another gets the real treatment, so researchers can compare them. People sometimes feel better after a placebo, often because they expect to or because of the care they receive; this is called the placebo effect. A sham procedure is a placebo version of a surgery or injection.; See alsoRandomized controlled trial Clinical trial
Platelet-rich plasma (PRP): Also called PRP; Platelet-rich plasma is plasma (the liquid part of blood) with extra platelets packed in. It comes from spinning the person's own blood so it separates into layers. Platelets are tiny cell pieces that help blood clot, and they carry growth factors, proteins that signal cells to grow and repair. A 2024 review of 75 randomized trials (studies that assign groups by chance), mostly on joint, tendon, skin and hair problems, found that studies made and described PRP in very different ways, so results are hard to compare.; See alsoGrowth factors Autologous Orthobiologics Randomized controlled trial
Pluripotent: Also called pluripotency, pluripotent cell; Create a free account to read this definition.; See alsoEmbryonic stem cell Induced pluripotent stem cell (iPSC)Multipotent Differentiation

R

Randomized controlled trial: Also called RCT, randomized clinical trial; A randomized controlled trial is a study that puts volunteers into groups by chance, much like flipping a coin, not by choice. One group gets the treatment being tested. Another, the control group, gets a placebo, usual care or a different treatment. Because chance does the sorting, the groups tend to be alike at the start, so a later difference between them is more likely due to the treatment. In a blinded trial, volunteers (and often researchers too) are not told who is in which group.; See alsoClinical trial Placebo Systematic review and meta-analysis
Regenerative medicine: Also called Regenerative medicine therapies, Regenerative therapies; Regenerative medicine is an area of medical research and care that aims to rebuild or restore body parts harmed by injury or disease, from single cells up to whole organs. One approach tries to boost the body's natural healing, sometimes by adding cells or growth factors (proteins that signal cells to grow). Another, called tissue engineering, grows new tissue on a support frame known as a scaffold. The FDA regulates these products and has warned that many sold to the public lack its approval.; See alsoStem cell therapy Tissue engineering Gene therapy Orthobiologics

S

Secretome (conditioned media): Also called Conditioned media, Conditioned medium, Stem cell secretome; Create a free account to read this definition.; See alsoExtracellular vesicles (EVs)Exosomes Growth factors Mesenchymal stem cell (MSC, mesenchymal stromal cell)
Stem cell: A stem cell is an unspecialized cell, meaning it has no set job in the body yet. When it divides, it can make more stem cells like itself or cells that mature into one particular type, such as a red blood cell or a nerve cell. This helps the body grow and replace worn-out cells. In the US, only a small number of stem cell products have FDA approval, and nearly all are blood-forming stem cells, many of them from donated umbilical cord blood.; See alsoAdult stem cell (tissue-specific stem cell)Embryonic stem cell Induced pluripotent stem cell (iPSC)Differentiation
Stem cell therapy: Also called Stem cell treatment, Stem cell-based therapy; In stem cell therapy, a patient is given stem cells, or cells grown from them, with the goal of treating an illness or helping injured tissue heal. Stem cells can keep copying themselves and can also turn into other, more specialized cells. The best-established type is a blood stem cell transplant (also called a bone marrow transplant), used for some blood cancers and other blood disorders. The FDA has approved only a small number of stem cell products and warns that many sold to the public are unapproved.; See alsoStem cell Stem cell transplant (bone marrow transplant)Unproven stem cell treatment FDA approval
Stem cell transplant (bone marrow transplant): Also called Bone marrow transplant, Hematopoietic stem cell transplant (HSCT), Hematopoietic cell transplant (HCT), Blood and marrow transplant; Create a free account to read this definition.; See alsoHematopoietic stem cell (blood-forming stem cell)Autologous Allogeneic Cord blood
Stromal vascular fraction (SVF): Also called SVF, adipose-derived stromal vascular fraction, AD-SVF; Create a free account to read this definition.; See alsoAdipose-derived stem cells (fat-derived stem cells)Minimal manipulation and homologous use (HCT/Ps)Autologous Unproven stem cell treatment
Systematic review and meta-analysis: Also called systematic review, meta-analysis, pooled analysis; Create a free account to read this definition.; See alsoRandomized controlled trial Clinical trial Placebo

T

Tissue engineering: Also called engineered tissue, bioengineered tissue; Create a free account to read this definition.; See alsoRegenerative medicine Growth factors Stem cell Differentiation

U

Unproven stem cell treatment: Also called Unapproved stem cell treatment, Unproven stem cell intervention; An unproven stem cell treatment uses a product described as containing stem cells, or substances they release, for a use where careful studies have not yet shown that the benefits outweigh the risks. These treatments are often marketed directly to the public, outside a clinical trial and without FDA approval. FDA has received reports of blindness, tumors and serious infections after their use, and a 2018 review of medical and news reports described 35 people who were harmed, some fatally.; See alsoStem cell therapy FDA approval Clinical trial Investigational New Drug (IND) application

W

Wharton's jelly: Also called Wharton jelly, WJ; Create a free account to read this definition.; See alsoPerinatal tissue (placenta, amniotic membrane and fluid, umbilical cord)Mesenchymal stem cell (MSC, mesenchymal stromal cell)Cord blood Unproven stem cell treatment

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