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    <recommendedItem id="20090101_19_2117"
                     title="Early Cardiac Stem Cells Identified"
                     score="-0.005"
                     href="http://www.medpagetoday.com/PublicHealthPolicy/StemCellResearch/tb/14958?impressionId=1265751336777"
                     
       LITTLE FALLS, N.J., July 5 -- The earliest master stem cells that form the three major cell types in the human heart have been identified and isolated, researchers said.
              &lt;p&gt; 
              &lt;p&gt;&quot;This is a very simple, but very important and fundamental finding,&quot; according to Kenneth Chien, MD, PhD, of the Harvard Stem Cell Institute and Massachusetts General Hospital in Boston, who led the effort.
              &lt;p&gt; 
              &lt;p&gt;Reporting online in &lt;em&gt;Nature&lt;/em&gt;, he and his colleagues described the process of isolating and purifying islet progenitor cells -- called ISL1+ progenitors -- from human embryonic stem cells.
              &lt;p&gt; 
              &lt;p&gt;These cells expand and then differentiate into heart muscle, smooth muscle, and endothelial cells during early cardiogenesis, a process that hadn&apos;t been well understood previously, according to Dr. Chien.
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              &lt;p&gt;He said the findings could have clinical implications in the future, particularly in the treatment of congenital heart disease, the regeneration and repair of damaged tissue following myocardial infarction, and the development of a human model to study heart disease and the effects of medications.
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              &lt;p&gt;&quot;It would be empowering to have human models of human cardiovascular disease,&quot; Dr. Chien said.
              &lt;p&gt; 
              &lt;p&gt;But on a conference call with reporters, he urged caution in interpreting the findings, which he said lay the groundwork for future studies.
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              &lt;p&gt;&quot;I don&apos;t want this to come across as hype,&quot; he said. &quot;I think there is some promise here. . . . But by no means do I believe that this cell or any of the cells described in this are ready for a clinical trial.&quot;
              &lt;p&gt; 
              &lt;p&gt;The current study extends the findings of previous studies Dr. Chien&apos;s group conducted in mice. (See &lt;a href=&quot;http://www.medpagetoday.com/PublicHealthPolicy/StemCellResearch/469&quot; target=&quot;blank&quot;&gt;Cardiac Stem Cells May Help Repair Heart Defects&lt;/a&gt; and &lt;a href=&quot;http://www.medpagetoday.com/PublicHealthPolicy/StemCellResearch/4578&quot; target=&quot;blank&quot;&gt;Cell Findings Go to Heart of Heart Development&lt;/a&gt;)
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              &lt;p&gt;The study helped answer the question of how a newborn human heart grows to 1,000 times the size of a newborn mouse heart, despite similar initial embryo sizes.
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              &lt;p&gt;Dr. Chien said the study showed that these master stem cells first expand, persisting until later stages of development in humans than in mice, and then differentiate into the three cell types.
              &lt;p&gt; 
              &lt;p&gt;Identifying and isolating these master stem cells in humans will allow rigorous study into the pathways by which they differentiate into the major types of cells, Dr. Chien said, and intermediate cells in these pathways will be the most likely candidates for stem cell therapies in the future.
              &lt;p&gt; 
              &lt;p&gt;Isolation of this master stem cell &quot;forms the basis for finding the downstream intermediate within its pathway to identify the means by which to isolate it and to grow it,&quot; he said.
              &lt;p&gt; 
              &lt;p&gt;The progenitors are concentrated in &quot;hotspots&quot; for congenital heart disease, including the outflow tracts that connect to the pulmonary artery and aorta.
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              &lt;p&gt;&quot;A stem cell-mediated process clearly exists for expansion of the human heart,&quot; Dr. Chien said, &quot;particularly in regions that are affected by congenital heart disease.&quot;
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              &lt;p&gt;This suggests, he said, &quot;that congenital heart disease may be a stem cell disease.&quot;
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              &lt;p&gt;Developing human models from the progenitor cells could aid in the search for treatments for diseases such as Duchenne muscular dystrophy, DiGeorge and Down syndromes, and rare genetic congenital heart diseases, Dr. Chien said.
              &lt;p&gt; 
              &lt;p&gt;In addition, understanding how the heart develops could help researchers find ways to augment undamaged cardiac muscle mass after myocardial infarction or the development of heart failure, he said.
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              &lt;p&gt;&quot;To understand how human cardiogenesis occurs is actually the blueprint for a new approach to regenerative therapy using these stem cells as opposed to already differentiated muscle cells,&quot; he said.
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              &lt;p&gt;&lt;table cellspacing=&quot;0&quot; hspace=&quot;1&quot; style=&quot;border-style:solid; border-width:1px; border-color:#8dabbc; font-family:arial; font-size:12px; background-color:#DBE9F2; padding:5px 5px 5px 5px;&quot;&gt;
&lt;tr&gt;&lt;td&gt; The study was supported by the Harvard Stem Cell Institute and the Leducq Foundation. Advanced Bioscience Resources provided the human fetal tissues used in the study. 
              &lt;p&gt;One of the study authors is funded by Foundation Alfonso Martin Escudero in Spain.&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;
    </recommendedItem>
    <recommendedItem id="20090101_19_4122"
                     title="Stem Cell Lines Said to Lack Population Diversity"
                     score="-0.005"
                     href="http://www.medpagetoday.com/PublicHealthPolicy/StemCellResearch/tb/17580?impressionId=1265751336777"
                     
      &lt;p&gt;People of African ancestry and some other ethnicities might not benefit from research on human embryonic stem cells (hESCs) because most of the cell lines in use came from people of European or Middle Eastern origin, researchers said.&lt;/p&gt;
&lt;p&gt;Although the specific origins of hESC lines are not available, genotype data on 47 commonly used lines suggested that none had African origins and only two came from Asians, according to Sean Morrison, PhD, of the University of Michigan, and colleagues.&lt;/p&gt;
&lt;p&gt;All the rest had genetic signatures characteristic of people from Europe and the Middle East, the researchers reported online in the &lt;em&gt;New England Journal of Medicine&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;&quot;The potential benefit to patient populations [of stem cell research] may depend partially on the diversity of the stem cell lines that are available for research and clinical use,&quot; they wrote.&lt;/p&gt;
&lt;p&gt;&quot;Availability of more diverse lines will reduce the risk that the potential benefits of stem cell research will be limited to patients with certain ancestries.&quot;&lt;/p&gt;
&lt;p&gt;Morrison and colleagues compared genotype information on the 47 hESC lines with published data on 2,001 individuals of known ancestry whose genotypes were included in the international HapMap and Human Genome Diversity projects.&lt;/p&gt;
&lt;p&gt;The data covered more than 480,000 single nucleotide polymorphisms (SNPs) in the human genome. The stem cell lines had been developed in the U.S., Europe, Israel, and Singapore. More than half were cultured at Harvard University.&lt;/p&gt;
&lt;p&gt;&quot;Nearly all the stem cell lines clustered exclusively with reference subjects of known European and Middle Eastern origin,&quot; Morrison and colleagues reported.&lt;/p&gt;
&lt;p&gt;Most of these lines appeared to derive from people of northern and western European ancestry, the researchers said, while the two lines of Asian origin were likely from the eastern end of the continent.&lt;/p&gt;
&lt;p&gt;The researchers also identified five sets, each comprising two or three lines, that apparently came from the same gamete donors, reducing the genetic diversity even more.&lt;/p&gt;
&lt;p&gt;Morrison and colleagues noted that other hESC lines are available for research that probably derive from different populations.&lt;/p&gt;
&lt;p&gt;But, they added, &quot;most published stem cell studies have used the lines that we investigated.&quot;&lt;/p&gt;
&lt;p&gt;The researchers said one way to increase the diversity of stem cell lines is to use induced (i.e., nonembryonic) pluripotent stem cells derived from ethnically varied individuals.&lt;/p&gt;
&lt;p&gt;On the other hand, Morrison and colleagues noted, it&apos;s possible that &quot;certain types of studies and therapies will be more readily performed with hESCs.&quot;&lt;/p&gt;

    </recommendedItem>
    <recommendedItem id="20090101_2_587"
                     title="Adult Skin Cells Reprogrammed into Stem Cells for Disease Research"
                     score="-0.005"
                     href="