Beware of Press Release science reporting – the job of the news release or public affairs department of an institution is to get publicity, not to promote scientific knowledge. There’s no peer review until after the fact, and the goal is to catch our attention, rather to educate.
A case in point was the announcement yesterday from the the University of Texas at Houston Brown Foundation’s Institute of Molecular Medicine researchers’ Press Release that begins:
UT Scientists Develop Promising New Procedure To Differentiate Human Embryonic Stem Cells
HOUSTON – (Feb. 26, 2007)—Molecular scientists at the Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases (IMM) – which is part of the University of Texas Health Science Center at Houston – have developed a new procedure for the differentiation of human embryonic stem cells, with which they have created the first transplantable source of lung epithelial cells.
The process, created in the laboratory of Rick A. Wetsel, Ph.D., a professor of molecular medicine at the IMM, is described in this week’s edition of the Proceedings of the National Academy of Sciences (PNAS). Research scientist Dachun Wang, M.D., is lead author of the article, “A pure population of lung alveolar epithelial type II cells derived from human embryonic stem cells.”
“We have developed a reliable molecular procedure which facilitates, via genetic selection, the differentiation of human embryonic stem cells into an essentially pure population of lung epithelial cells,” said Wetsel, noting the procedure also can be used to create other types of highly-specialized cells.
The word that seems to carry the most weight in that first paragraph is “transplantable.” And a lot depends on how they define that word.
Since I can’t find any mention of the article on the internet, except in the press releases, I’m not sure exactly what “transplantable” cells means to these guys.
However, I am convinced that they are not the only ones to derive alveolar II lung epithelial cells from stem cells.
As reported, here and very few other places, last November 1, 2006 – you know, just before the Midterm election and Missouri’s disaster with the clone and kill bill – researchers at the University of Minnesota Medical School at Minneapolis published a report in Cytotherapy on their production of functioning alveolar II epithelial lung cells, capable of producing surfactant, from a certain population of umbilical cord blood stem cells:
BackgroundUmbilical cord blood (UCB) has been examined for the presence of stem cells capable of differentiating into cell types of all three embryonic layers (i.e. endo-, ecto- and mesoderm). The few groups reporting success have typically confirmed endodermal potential using hepatic differentiation. We report differentiation of human UCB-derived multipotent stem cells, termed multilineage progenitor cells (MLPC),into respiratory epithelial cells (i.e. type II alveolar cells).
Methods Using a cell separation medium (PrepaCyte-MLPC; BioE Inc.) and plastic adherence, MLPC were isolated from four of 16 UCB units (American Red Cross) and expanded. Cultures were grown to 80% confluence in mesenchymal stromal cell growth medium (MSCGM; Cambrex BioScience) prior to addition of small airway growth medium (SAGM; Cambrex BioScience), an airway maintenance medium. Following a 3-8-day culture, cells were characterized by lightt microscopy, transmission electron microscopy, immunofluorescence and reverse transcriptase (RT)-PCR.
Results MLPC were successfully differentiated into type II alveolar cells (four of four mixed lines; two of two clonal lines). Differentiated cells were characterized by epithelioid morphology with lamellar bodies. Both immunofluorescence and RT-PCR confirmed the presence of surfactant protein C, a protein highly specific for type II cells.
Discussion MLPC were isolated, expanded and then differentiated into respiratory epithelial cells using an off-the-shelf medium designed for maintenance of fully differentiated respiratory epithelial cells. To the best of our knowledge, this is the first time human non-embryonic multipotent stem cells have been differentiated into type II alveolar cells. Further studies to evaluate the possibilities for both research and therapeutic applications are necessary.
Unfortunately, most of the sites that are picking up the PR are just publishing it whole, without evaluation or editing.
For instance, ScienceDaily, one of my favorite science news sites, published the intact, clearly labeled “Press Release”, although that site also published the press release on the earlier, UCB stem cell derivation of alveolar II cells.
So far, I’ve only seen one note on the UT announcement that distills the info available to the news, without the hype. LongevityMeme, a blog devoted to technology and science showing promise for the extension of the human lifespan, has not duplicated the silly “transplantable” or “first” claims. The post explains the pertinent points very well (click to the original for the embedded links):
Examples of continually improving control over stem cells have been rolling in of late; here is one from the University of Texas: “We have developed a reliable molecular procedure which facilitates, via genetic selection, the differentiation of human embryonic stem cells into an essentially pure population of lung epithelial cells … the procedure also can be used to create other types of highly-specialized cells. … The method involves the use of protein markers under the control of cell-specific promoters to convert undifferentiated human embryonic stem cells into highly-specialized cells. The human embryonic stem cells were cultured on specially coated dishes and transfected with a lung epithelial gene regulator of a drug selection gene. … It is a general technology for developing select cells from human embryonic stem cells. The technology has allowed us to develop a platform that could potentially be useful in the development of spinal cord cells, heart cells, nerve cells and others. … transplantable alveolar epithelial type II cells can be explored as treatments for pulmonary genetic diseases, acquired lung disease, as well as lung trauma caused by car accidents, gunshot wounds and sports injuries. … These are the cells that can potentially be used for regenerative lung repair.”
(emphasis is mine)
The “transfected gene” treatment used to induce the embryonic stem cells to develop along the desired line appears to me to be a step that will complicate the testing and approval of the use of these cells in humans. I’m not convinced that surgery will be the optimum use of the outcome of stem cell regenerative medicine. I’m convinced that we will use what we learn to induce, stimulate and and recruit the body’s own regenerative stem cells in place, as we need them
If the transfected gene is safe, then, perhaps it will be the treatment in the future. Or, perhaps the UT lab and the UM lab can co
llaborate on truly transplantable cells, if necessary.