Stem cells in the most unexpected places
Time was when pleuripotent stem cells were supposedly only available from human embryos which led to heated debates on ethics and morality.
Since then, multipotent stem cells have been isolated from different organs of the human body, be it from the umbilical cord blood, the bone marrow, even from the skin. Recent research studies have now pinpointed even more unexpected sources of stem cells.
Stem cells in menstrual blood [1, 2]
Researchers at the University Pittsburgh’s McGowan Institute of Regenerative Medicine observed that menstrual blood stromal cells (MenSCs) exhibit a great capacity for self-renewal and multipotency.
Stem cells in breast milk [3]
On the other side of the globe, researchers at the University of Western Australia recovered the stem cell markers nestin from breast milk. These cells physically resemble stem cells and could potentially behave like stem cells.
If nestin and MenSCs indeed prove to be as plastic and pleuripotent as embryonic stem cells, then, we may have found stem cell sources which are unlimited, inexpensive, most of all, noncontroversial. Furthermore, these cells are easily collectable without resorting to invasive techniques.
Sources:
- Eureka Alert, 23 April 2008
- Patel et al. Cell Transplantation 2008; 17: 303-311
- Science Alert, 10 February 2008
The year that was: major events in 2007
Nature`s Daniel Cressey listed several events as among the most newsworthy in 2007. Some of these events are discussed below.
Biotechnology
November was a good month for biotechnology. American and Japanese researchers derived pleuripotent stem cells from human skin. American researchers also finally succeeded cloning primate embryos in the same month. Both events are major breakthroughs in stem cell research.
This year, two big names in genomics - James Watson and Craig Venter – had their full genome sequenced. In the meantime, American start ups are offering personalized genetic information service (see October post).
Climate Change
The Intergovernmental Panel on Climate Change (IPCC) was co-winner of the Nobel Prize for Peace. In the meantime, the Northwest Passage that connects Atlantic and Pacific Oceans was practical ice-free and passable – a record low in the arctic ice cover. If the IPCC reports and this ice shrinkage do not convince people of the reality of global change, nothing ever will.
Pharmaceutical scandals
China’s former head of food and drug regulatory agency was executed in July after having been convicted of corruption. In the USA, the Avandia scandal rages on. The USA FDA required an additional black box warning for the diabetes medication Avandia (rosiglitazone) labelling last year but Avandia`s troubles didn’t stop there. The latest involved a US senate inquiry and a leak by an NEJM reviewer.
Safety issues
The July earthquake in Japan caused a leak in a major nuclear reactor, reawakening concerns over nuclear energy safety in general.
Two incidences of major biosecurity lapses were reported this year. In the UK, a leaky pipe caused an outbreak of foot-and-mouth disease. In a bioweapons research lab at the Texas A&M University, researchers were exposed to biohazards.
Space technology
Japan and China launched moon probes in 2007 though there were doubts whether China’s claims of success were authentic. China also tested a space weapon by shooting at one of its defunct satellites, scattering potentially dangerous debris in space.
Wired magazine considered the following as the top 10 scientific breakthrough of 2007:
10. Transistors Get Way Smaller
9. Scientists Clone Rhesus Monkey to Produce Stem Cells
8. Planet Discovered That Could Harbor Life
7. Engineers Create Transparent Material as Strong as Steel
6. Soft Tissue from T. Rex Leg Bone Analyzed
5. Laboratory Mice Cured of Rett Syndrome
4. Enzymes Convert Any Blood Type to O
3. Mummified Dinosaur Excavated and Scanned
2. Chimpanzees Make Spears for Hunting
1. Researchers Turn Skin Cells to Stem Cells
References:
Cressey D. News 2007. Nature 450, 1134-1135 (2007)
Rowe A. Top 10 Scientific Breakthroughs of 2007. Wired 27 Dec 2007.
Nonclinical Studies: The Latest in Adult Stem Cell Research in Mice
In the latest issues of Nature and Science, two articles report on promising therapies using adult stem cells.
American and German researchers demonstrated that embryonic stem cells can mend post-infarction heart muscles without causing ventricular tachyarrhythmias. Following cardiomyocyte implantation, mice were protected against the induction of ventricular tachycardia. This was not evident when adult and bone marrow stem cells were used in the engraftment. The reason may be the fact that embryonic heart stem cells have a high degree of expression of the gap-junction protein connexin 43. Bone marrow stem cells engineered to express this protein afforded similar protection [1].
In another in vivo study, researchers successfully treated sickle-cell anemic mice using adult murine stem cell lines. The test mice were genetically-engineered to have a sickle-cell hemoglobin allelle, producing a “humanized sickle cell anemia mouse model.” The adult stem cells from these animals were reprogrammed to become pluripotent and their faulty allele was corrected by gene-specific targeting. Following transplantation of these reprogrammed and corrected cells, treated mice exhibited higher RBC counts and hemoglobin levels than control mice [2].
The results of these studies demonstrate potential cell-based therapies using adult stem cells.
[1] Roell, W. et al. Nature 450, 819-824 (6 December 2007)
[2] Hanna, J. et al. Science doi:10.1126/science.1152092 (6 December 2007)