40 Fun Facts About Stem Cells

After a donor stem cell transplant, which lifelong trait of the patient can switch to match the donor's?

Blood type switches because the donor's stem cells take over the job of making every red cell, so a type O patient given type A marrow ends up type A.

Timothy Ray Brown, the Berlin patient, was the first person cured of which infection by a stem cell transplant?

HIV became undetectable in his body after doctors treating his leukemia picked a donor with a rare genetic variant that stops the virus attaching to cells.

The lowercase 'i' in iPS cells, the reprogrammed stem cells first made in 2006, was a nod to which Apple product?

The iPod was hugely popular at the time, so the discoverer borrowed its small first letter. The full name is induced pluripotent stem cells.

Planarians, which regrow a whole body from a sliver using stem cells called neoblasts, are what kind of animal?

Flatworms of this kind have been called immortal under the edge of a knife: a piece as small as 1/279th of the animal can rebuild a complete body in a few weeks.

Dolly the sheep, a 1996 landmark for stem cell science, was cloned using a cell from which part of a ewe?

A mammary gland cell supplied her DNA, which is why the scientists named her after the singer Dolly Parton. She showed that a specialized adult cell could still build a whole animal.

Which Back to the Future star made 2006 campaign ads backing embryonic stem cell research?

Michael J. Fox, who has Parkinson's disease, let its visible effects show on camera in the ads, which were made for a Senate candidate in Missouri who supported the research.

The death of pigment-making melanocyte stem cells triggers which familiar sign of getting older?

Gray hair appears once those stem cells at the base of a follicle die off, because each new hair then grows in without any pigment.

Which US president used his first veto to block wider federal funding of embryonic stem cell research?

George W. Bush went more than five years in office without vetoing anything, then in July 2006 rejected a funding bill that both houses of Congress had passed.

Blood from which structure, usually thrown away after a birth, is now banked for its blood-forming stem cells?

Umbilical cord blood was first transplanted in 1988, into a child with the rare disorder Fanconi anemia. It is frozen in banks because it can only be collected at a birth.

Stem cells turned into pancreatic beta cells are being tested for type 1 diabetes because they make which hormone?

Insulin is what people with type 1 diabetes cannot make, because their own immune system destroys the beta cells that release it.

Which Japanese scientist shared the 2012 Nobel Prize in medicine for turning adult cells back into stem cells?

Shinya Yamanaka showed in 2006 that switching on just four genes could rewind a mature cell to an embryo-like state, with no egg or embryo needed.

John Gurdon shared a Nobel Prize for work begun in 1958, when he cloned which animal from an ordinary body cell?

A frog raised from the nucleus of a tadpole's body cell showed that specialized cells keep every gene needed to build a whole animal, decades before Dolly.

Martin Evans and Matthew Kaufman isolated the first embryonic stem cells in 1981 from embryos of which animal?

Mouse embryos gave biologists their first embryonic stem cells, and Evans later shared a Nobel Prize for using such cells to breed animals with chosen genes altered.

Stem cell therapies for Parkinson's disease aim to replace lost neurons that make which brain chemical?

Dopamine-making neurons die off in a small midbrain region called the substantia nigra, and most of them are already gone by the time movement symptoms appear.

Surgeons collecting bone marrow for a stem cell transplant usually draw it through a needle from which bone?

The pelvis is a large bone that a long needle can reach under anesthetic, though stem cells can also be filtered straight from a donor's bloodstream by apheresis.

Which US state's voters approved Proposition 71 in 2004, committing $3 billion to stem cell research?

California voters passed the measure with 59% support, creating a state institute to pay for work that federal rules at the time would fund only on older cell lines.

Hwang Woo-suk, whose cloned human stem cell lines were exposed as fabricated in 2005, worked in which Asian capital?

Seoul National University found that all eleven of his stem cell lines were invented, though his team's cloned dog, an Afghan hound named Snuppy, turned out to be real.

Most human embryonic stem cell lines were made from surplus embryos that labs acquired from which medical setting?

IVF clinics create more embryos than patients end up using, and supporters of the research argue the spares would otherwise be thrown out as medical waste.

Conditioning before a stem cell transplant clears the patient's bone marrow using radiation or which other treatment?

Chemotherapy in very high doses wipes out the diseased marrow and also damps down the immune system, so the incoming cells are less likely to be rejected.

People who join a volunteer stem cell donor registry usually give their first tissue sample in which simple way?

A cheek swab mailed back in a prepaid envelope is all it takes to join. Registries exist because most patients have no fully matched donor in their own family.

In stem cell biology, which term describes a fertilized egg, whose single cell can give rise to a whole organism?

Totipotent cells exist only for the first few divisions after fertilization, and unlike embryonic stem cells they can also build the placenta.

Embryonic stem cells come from the inner cell mass of which embryo stage, reached about five days after fertilization?

The blastocyst is a ball of only 50 to 150 cells, and removing its inner cluster destroys it, which is the root of the ethical dispute over the research.

Stem cells are defined by two abilities: becoming specialized cells and which other property?

Self-renewal lets a stem cell divide again and again while staying unspecialized, often by splitting into one copy of itself and one daughter that goes on to mature.

In most adult mammals, neural stem cells keep producing new neurons in which brain region tied to memory formation?

The hippocampus is one of only two brain regions where new neurons are born throughout adulthood. Cells from the other travel to the olfactory bulb and serve the sense of smell.

Satellite cells are the resident stem cells that wake up after injury or hard exercise to repair which tissue?

Muscle repair depends on these cells, which lie dormant beside each fiber until damage signals them to multiply and fuse with the injured fibers.

Stem cells at the base of pits called crypts constantly replace the lining of which organ?

The intestine renews its lining so fast that each division leaves one daughter in the crypt as a stem cell while the other climbs toward the surface and is shed within days.

Holoclar, the first stem cell medicine approved in Europe, uses limbal stem cells to repair which part of the body?

The cornea is kept clear by stem cells at its rim, and Holoclar grows a patient's own surviving ones in the lab to resurface an eye damaged by burns.

The multipotent stem cells known as SHED are collected from which part of a child's body?

Baby teeth hold living pulp, and its stem cells are simple to gather because the teeth fall out by themselves or are pulled to make room for adult ones.

What name is given to the tiny, simplified versions of organs that scientists grow from stem cells?

Organoids organize themselves as they grow, and since 2013 labs have made versions that mimic the developing human brain.

A patient whose blood is made by a donor's stem cells fits which term for one organism built from two genotypes?

A chimera is a single organism made of cells with different genotypes, and the word also covers lab animals created by injecting embryonic stem cells into another embryo.

Adult stem cells, found in mature tissues of children as well as adults, are also known by which other name?

Somatic comes from the Greek for 'of the body', a more accurate label than adult, since these stem cells are present in children too.

Which adult stem cells, named by Arnold Caplan, are defined by their ability to form bone, fat and cartilage?

Mesenchymal stem cells were first found in bone marrow, but fat tissue has become a popular source because it yields more of them and is easier to reach.

A stem cell transplant that uses a patient's own stored cells, rather than a donor's, is described by which term?

Autologous transplants need no search for a match: the patient's cells are collected, frozen and returned after high-dose treatment, a standard option for lymphoma.

Embryonic stem cells can divide in the lab indefinitely partly thanks to which enzyme that rebuilds chromosome ends?

Telomerase restores the protective caps that shorten with every division, and most adult body cells keep it switched off, which limits how often they can divide.

Embryonic stem cells injected straight into a body can grow into which tumor, a jumble of several tissue types?

A teratoma takes its name from the Greek for monster, and labs use the ability to form one in a rodent as a standard test that cells are truly pluripotent.

Surgeon Paolo Macchiarini was convicted over transplants of stem-cell-seeded synthetic versions of which body part?

Windpipe implants built on synthetic scaffolds and seeded with the patients' own cells were followed by the deaths of seven of the eight people who received them.

The retracted 2014 STAP papers claimed ordinary cells turned into stem cells after half an hour soaking in what?

A weak acid bath sounded almost too simple, and no other lab could repeat the result. An inquiry by the RIKEN institute found the lead author had falsified data.

Which gene, one of four used to make the first iPS cells, is also a notorious cancer-promoting oncogene?

Myc belongs to a gene family implicated in cancer, so researchers later made iPS cells without it. The process was slower, but the resulting animals did not develop cancer.

In 2014 a Japanese woman became the first person to receive cells made from iPS cells, to treat which eye condition?

Macular degeneration blurs the center of vision, so surgeons in Kobe placed a sheet of lab-grown retinal cells in the eye of a patient in her seventies.

James Till and Ernest McCulloch first defined the key properties of stem cells in the 1960s in which Canadian city?

Toronto is where the pair injected bone marrow cells into irradiated animals and showed that each lump growing on the spleen had sprung from a single cell.