Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.
New type of stem cell easier to grow, more versatile. Both the professional scientific media and the lay science media devoted considerable ink and electrons this week to the announcement of a new type of stem cell—and not just any stem cell, a pluripotent one, so it is capable of making all our tissues. On first blush it appears to be easier to grow in the lab, possibly safer to use clinically, and potentially able to generate whole replacement organs.
The newly found stem cells (shown in green) integrating into a mouse embryo.
How a team at the Salk Institute made the discovery was perhaps best described in the institute’s press release picked up by HealthCanal. They sought to isolate stem cells from a developing embryo after the embryo had started to organize itself spatially into compartments that would later become different parts of the body. By doing this they found a type of stem cell that was on the cusp of maturing into specific tissue, but was still pluripotent. Using various genetic markers they verified that these new cells are indeed different from embryonic stem cells isolated at a particular time in development.
The Scientist did the best job of explaining why these cells might be better for research and why they might be safer clinically. They used outside experts, including Harvard stem cell guru George Daly and CIRM-grantee from the University of California, Davis, Paul Knoepfler, to explain why. Paul described the cells this way:
“[They] fit nicely into a broader concept that there are going to be ‘intermediate state’ stem cells that don’t fit so easily into binary, black-and-white ways of classifying [pluripotent cells].”
The Verge did the best job of describing the most far-reaching potential of the new cells. Unlike earlier types of human pluripotent cells, these human stem cells, when transplanted into a mouse embryo could differentiate into all three layers of tissue that give rise to the developing embryo. This ability to perform the full pluripotent repertoire in another species—creating so called chimeras—raises the possibility of growing full human replacement organs in animals, such as pigs. The publication quotes CIRM science officer Uta Grieshammer explaining the history of the work in the field that lead up to this latest finding.
Stem cells boost success in in vitro fertilization. Veteran stem cell reporter and book author Alice Park wrote about a breakthrough in Time this week that could make it much easier for older women to become pregnant using in vitro fertilization. The new technique uses the premise that one reason older women’s eggs seem less likely to produce a viable embryo is they are tired—the mitochondria, the tiny organs that provide power to cells, just don’t have it in them to get the job done.
The first baby was born with the assistance of the new procedure in Canada last month. The process takes a small sample of the mother-to-be’s ovarian tissue, isolates egg stem cells from it, extracts the mitochondria from those immature cells and then injects them into the woman’s mature, but tired eggs. Park reports that eight women are currently pregnant using the technique. She quotes the president of the American Society of Reproductive Medicine on the potential of the procedure:
“We could be on the cusp of something incredibly important. Something that is really going to pan out to be revolutionary.”
But being the good reporter that she is, Park also quotes experts that note no one has done comparison studies to see if the process really is more successful than other techniques.
Why bug linked to ulcers may cause cancer. The discovery of the link between the bacteria H. pylori and stomach ulcers is one of my favorite tales of the scientific process. When Australian scientists Barry Marshall and Robin Warren first proposed the link in the early 1980s no one believed them. It took Marshall intentionally swallowing a batch of the bacteria, getting ulcers, treating the infection, and the ulcers resolving, before the skeptics let up. They went on to win the Nobel Prize in 1995 and an entire subsequent generation of surgeons no longer learned a standard procedure used for decades to repair stomach ulcers.
In the decades since, research has produced hints that undiagnosed H. pylori infection may also be linked to stomach cancer, but no one knew why. Now, a team at Stanford has fingered a likely path from bacteria to cancer. It turns out the bacteria interacts directly with stomach stem cells, causing them to divide more rapidly than normal.
They found this latest link through another interesting turn of scientific process. They did not feel like they could ethically take samples from healthy individuals’ stomachs, so they used tissue discarded after gastric bypass surgeries performed to treat obesity. In those samples they found that H. pylori clustered at the bottom of tiny glands where stomach stem cells reside. In samples positive for the bacteria, the stem cells were activated and dividing abnormally. HealthCanal picked up the university’s press release on the work.
Rational balanced discussion on gene-edited babies. Wired produced the most thoughtful piece I have read on the controversy over creating gene-edited babies since the ruckus erupted April 18 when a group of Chinese scientists published a report that they had edited the genes of human eggs. Nick Stockton wrote about the diversity of opinion in the scientific community, but most importantly, about the fact this is not imminent. A lot of lab work lies between now and the ability to create designer babies. Here is one particular well-written caveat:
“Figuring out the efficacy and safety of embryonic gene editing means years and years of research. Boring research. Lab-coated shoulders hunched over petri dishes full of zebrafish DNA. Graduate students staring at chromatographs until their eyes ache.”
He discusses the fears of genetic errors and the opportunity to layer today’s existing inequality with a topping of genetic elitism. But he also discusses the potential to cure horrible genetic diseases and the possibility that all those strained graduate student eyes might bring down the cost to where the genetic fixes might be available to everyone, not just the well heeled.
The piece is worth the read. As he says in his closing paragraph, “be afraid, be hopeful, and above all be educated.”