Bone marrow transplants were the first successful type of stem cell therapies

Using stem cells for bone marrow transplants

Stem cells hold promise for many future medical applications, but only one type of stem cell is currently approved for use. This page offers a clear description of adult stem cells called hematopoietic stem cells, which create the full range of blood cells and are approved for use in treatments such as bone marrow transplants.

Bone marrow generates roughly 500 billion new blood cells each day.

New blood cells are created by hematopoietic stem cells

Blood is made up of several cells with various functions and short lifespans, so the body must have a constant supply of replacements. These replacements are created by hematopoietic stem cells, rare cells that live in bone marrow and can regenerate themselves and blood cells.

Stem cells develop into a wide range of other specialized cells in the human body

Stem cells are different from other cells because they are capable of creating copies of themselves and producing other types of cells. For example, the ones found in our brains, bones, or muscles. Curious about stem cells? Here's a breakdown of how they work.

How do stem cells actually work?

Stem cells are unspecialized cells that can develop into various cell types while also making exact replicas of themselves. This amazing ability has made stem cells a candidate to treat a wide variety of diseases and conditions—though the vast majority of potential therapies remain in the research stage.

There are three types of stem cells, each with different properties

Embryonic stem cells are "blank slates" that can change into any other type of cell. Adult stem cells can become specialized cells to replenish the supply or repair injury, while induced pluripotent cells are "reset" by scientists and used in clinical and medical applications.

‘Hope for Healing’: The first-ever use of an in utero stem cell treatment

In 2023, researchers at UC Davis performed the first-ever fetal stem cell transplant, attempting to cure a case of spinal bifida prior to childbirth using stem cells derived from the placenta. The trial, and others including an effort to treat muscular dystrophy, highlight the potential power of stem cell therapy.

Stem cells have the ability to self-renew

Stem cells have remarkable potential for new medical therapies. But to understand what makes stem cells so special, you must understand exactly what they are, and what they’re capable of doing. This page offers an accessible introduction to stem cell biology and their unique properties.

Without the option of modern blood transfusions, some doctors in the mid-1800s tried to help save cholera patients by injecting them with cow's milk, hoping it would boost their nutrition and hydration.

Stem cells become specialized cells through the activation or silencing of specific genes

After fertilization, when a sperm cell fuses with an egg, the resulting stem cell is described as totipotent—capable of transforming into any type of body cell or embryonic structures (e.g., placenta). Once differentiated into multipotent cells, they can only specialize further within specific cell type families, such as hematopoietic cells that become platelets and red and white blood cells.

Embryonic stem cells can develop into any other cell type in the body

Embryonic stem cells emerge around five days after fertilization, during the blastocyst stage of embryonic development. At this point, the embryo consists of about 100 to 150 cells and forms a hollow structure, and these cells are the ultimate source of all other cell types during fetal development.

In 2023, the FDA approved gene therapy for sickle cell disease, enabling one-time infusion bespoke treatments that use a patient's own stem cells to effectively cure a painful condition that disproportionately affects people of African American descent.

How to turn any cell of the body into a stem cell

Scientists have developed techniques allowing them to 'reprogram' any cell in the body into an induced pluripotent stem (iPS) cell, which can be used to create either more stem cells or specialized cells for use in experimental medical treatments. This page gives readers a brief introduction to the history of iPS cells, what researchers are studying with iPS cells, and challenges associated with iPS research.

Stem cell therapies

Stem cells' special attributes interest researchers developing new therapeutic tools for a variety of health problems. Much of this research is done with support from the National Institutes of Health (NIH). This page offers a snapshot of research programs funded by the NIH and the health problems those programs focus on.

Stem cells can reboot the ability of cells to repair themselves

Stem cells—special cells that can self-renew and evolve into new cell types—may provide a path to address aging. Instead of repairing aging cells, stem cells can replace a cell's "repair kit," effectively rebooting the internal processes of tissues to a more youthful state.

See this list of FDA-approved gene therapies, including offerings for inherited conditions as well as some forms of cancer.

Stem cell therapy has shown promise in treating spinal injuries in an early-stage clinical trial.

When was the first blood transfusion?

In the 1600s, an English doctor transferred the blood from one dog to another via quills. The procedure ended when one of the dogs died. This article details the early days of blood transfusions, which turned toward humans shortly after the 1666 dog experiment and involved putting the blood of a sheep into a human recipient (who reportedly survived the encounter).

What conditions can be treated with stem cells?

Stem cell research is a global enterprise, and much of the work is being done in Europe. This page gives readers a good sense of the medical conditions stem cell researchers in Europe focus on, and the specific research challenges they address. This page also offers links to in-depth information about many of the research projects.

The first successful organ transplant was performed in 1954

The successful kidney transplant procedure, at what's now-called Brigham and and Women's Hospital, ushered in a new medical era and gave hope to patients with organ failure. The recipient, 23-year-old Richard Herrick, lived eight more years after receiving the donated organ from his living twin brother, Ronald.

An interactive explanation of blood transfusion

The antigens and Rh factors of blood cells (which determines your blood type) must be compatible with your immune system—which is why blood transfusions between patients must have matching types. In a mismatch, the immune system will attack and destroy donor blood cells, triggering a potentially fatal reaction.

Teaching immune cells to fight cancer

CAR T-cell therapy is a type of immunotherapy, which involves strengthening the immune system to attack cancer cells. Patient T cells, which manage immune responses and are responsible for killing pathogen-infected cells, are collected and re-engineered to produce surface-level proteins called chimeric antigen receptors. These CARs, now able to bind to specific proteins on cancer cell surfaces, are multiplied into the millions and infused back into the patient.

The difference between embryonic and adult stem cells

The main difference between embryonic and adult stem cells lies in their potential and origin. The former can become any cell type in the body, while the latter are limited to specific cell types. Embryonic stem cells also carry ethical concerns when used in medical or clinical applications.

Gene therapy can occur inside the body, but it can also be completed outside the body—with scientists treating cells in the lab, and then those corrected cells are transplanted back into the body.

Explore the abundance of different types of cells in the human body

Lacking a nucleus and other organelles to maximize space for oxygen-carrying hemoglobin and enhance maneuverability through narrow capillaries, there are about four times as many red blood cells and platelets as all other cell types in the body combined. However, about half of the body's cell biomass consists of skeletal myocytes, or muscle fibers.

Each second, the human body produces 2 million to 3 million new red blood cells.

In vitro gametogenesis: using induced stem cells to fertilize eggs

Using stem cells from skin and mouth cells could save hopeful parents time and money and spare egg donors from significant amounts of discomfort throughout the process. There are potential consequences, not just for infertility treatment, but for the ability to create customized cells of any type.

Why CAR-T therapy has become one of the main focus areas for autoimmune diseases

The therapy, originally targeting cancer, involves taking a patient's own T cells, genetically reprogramming them to recognize and attack a specific target and then infusing them back into patients. For autoimmune diseases, the therapy instead programs them to target immune cells that are causing problems, restoring immune system tolerance.

Explore the microscopic composition of blood.

The first CRISPR-approved treatment was for sickle cell anemia in 2023

Victoria Gray was the first patient to receive a CRISPR-based therapy, which eliminated her symptoms and restored her health. The therapy's initial cost of $2.2M has kept it out of reach of many patients.

Living donations most commonly involve a kidney or part of a liver

In 2023, more than 6,900 transplants were made possible thanks to living donors. Living donation is when a living person donates an organ or part of an organ—usually one of their two kidneys or part of the liver, since that organ can regenerate in a healthy person. Much more rarely, living donors donate other organs. Living donations often occur when someone wants to ensure a loved one has certainty that they will quickly receive a needed organ.

A new type of immunotherapy focuses on healthy cells hijacked by tumors

Purdue University scientists are at work on a new cancer treatment that attacks immune system cells that feed and protect cancer cells rather than attacking them. The immunotherapy process promises to become a universal treatment for solid tumors. Thus far, the treatment has been tested and shown to work on human tumor cells in the laboratory and animal models.

How Gleevec transformed leukemia treatment and cancer research

An outline of the discovery of imatinib (Gleevec), a ground-breaking drug that transformed the treatment of chronic myelogenous leukemia and sparked the beginning of precision medicine.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Cross-species transplantation has been attempted in medicine for more than 300 years.

See how CAR-T cell therapy works to help fight cancer

Short for chimeric antigen receptor T-cell therapy, CAR-T Cell Therapy helps augment the body's own ability to attack cancer cells. It's a cell-based gene therapy that alters the genes in a person's T cells—which are a type of immune cell—to help them beat back cancerous growths.

Why don't we synthesize blood?

We're trying. Scientists are currently working on creating viable synthetic blood, an alternative to the presently relied-upon donations that manage to fall short of demand. More than half of the world's nations struggle to meet their population's need for blood. This article details current and historical efforts to develop synthetic blood, a venture that started more than 400 years ago.

Henrietta Lacks' tumor cells became the first recognized 'immortal' cell line about 75 years ago, but researchers are still investigating the specific mechanisms that enabled the cells to continuously grow and divide in the laboratory.

A clinical trial is underway in 2026 to help kidney transplant recipients avoid a lifetime of immunosuppressing drugs

This later-stage clinical trial, in Chicago and Taiwan, evaluates the efficacy and safety of a new cellular therapy that may be swapped in for immunosuppressing drugs among kidney transplant recipients. The study randomizes people to either receive standard immunosuppressants or this cellular therapy and fewer immunosuppressants. It only includes kidney transplant recipients receiving organs from live donors so transplant surgery timing won't hinge on the unpredictable schedule of performing surgery and follow-up care when a donor dies.

Blood has evolved many times over hundreds of millions of years, resulting in different blood colors and compositions—and there are even some organisms that don't need blood at all.

How did segregation in the US affect blood donations?

When the US established its first nationwide network of blood banks in 1941 with the hopes of restoring the dwindling reserves of military members, it was quick to emphasize blood donated by Black Americans wouldn't coat the veins of white servicemen. Historians say this policy was meant to appease white Southerners who believed Black blood was inferior to their own.This policy was leaked to the press that same year.

Limb regeneration research may lead to treatments for arthritis

For scientists pursuing the cure for arthritis, the holy grail of discoveries lies in how to regrow healthy cartilage inside human joints. While this feat has so far resisted our best scientific attempts, there are plenty of other human tissues—such as the liver and fingertips—that will successfully regenerate.

Scientists using gene therapy recently managed to regenerate retinal cells in the lab—a breakthrough for mammals that could potentially lead to future treatments for human retinal diseases.

What is immunotherapy and how does it work?

Immunotherapy is a type of treatment that harnesses the body's immune system to combat cancer. This video explainer from the American Cancer Society discusses various types of immunotherapies and their roles in targeting cancer cells. Still a new and quickly evoliving field, immunotherapy represents a significant advancement in cancer treatment and offers new options for patients.

Explore this blood type interactive to learn more about how the 8 most common blood types are defined.

What does blood do?

Blood's primary purpose is to ferry oxygen and nutrients to cells in need while collecting cell waste and byproducts for removal. It also enables the body's repair and immune systems to traverse our internal landscape to address cell damage or external invaders, such as viruses and parasites. Zooming out from the exact roles of blood's various cells, the fluid connective tissue also assists with maintaining homeostasis via temperature regulation and pH balance.

The spread of fraudulent stem cell treatments

All the coverage of research into promising (but often unproven) medical treatments involving stem cells has created conditions allowing some people to engage in activities regulators describe as scams. As this news article explains, attorneys general in at least seven states have taken legal action against businesses that promised (costly) stem cell treatments but allegedly engaged in fraud.

Gene therapy treats a disease by editing the disease's underlying DNA, replacing it with a functional variant.

60 years after seeing Henrietta Lacks as a patient, her doctor still remembered the unique cervical tumor that gave rise to the 'immortal' cell line now commonly used in biomedical research—it was purple, shiny, and soft—an appearance he said is very different from a typical tumor.

The first child born via mitochondrial replacement therapy was born in 2016

The healthy baby boy's mother carried genes for a rare mitochondrial disease called Leigh syndrome and after multiple miscarriages the family opted to try the controversial procedure. It was conducted by a US doctor in Mexico. The procedure is prohibited in the United States.