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[IPu] Fw: [IPp] Spleen may be source of versatile stem cells



Email 2
----- Original Message ----- 
From: "Rachel A" <email @ redacted>
To: "Rachel A" <email @ redacted>
Sent: Friday, January 21, 2005 8:28 AM
Subject: [IPp] Spleen may be source of versatile stem cells


> Remember this from a year or so
> ago?http://www.eurekalert.org/pub_releases/2005-01/mgh-smb011805.phpSpleen 
> may
> be source of versatile stem cellsCells have protein associated with 
> embryonic
> development, limb regenerationA year ago, Massachusetts General Hospital 
> (MGH)
> researchers discovered that the spleen might be a source of adult stem 
> cells
> that could regenerate the insulin-producing islets of the pancreas. In a
> follow-up to that unexpected finding, members of the same team now report 
> that
> these potential adult stem cells produce a protein previously believed to 
> be
> present only during the embryonic development of mammals.
> The finding both supports the existence of these splenic stem cells and 
> also
> suggests they may be able to produce an even greater variety of tissues. 
> The
> report appears in the January 19 issue of SAGE KE 
> (http://sageke.sciencemag.org
> ), an online resource on the science of aging from the publishers of the 
> journal
> Science.
> "There may be a previously undiscovered pocket of primitive stem cells in 
> the
> spleen that are important for healing several types of damage or injury," 
> says
> Denise Faustman, MD, PhD, director of the MGH Immunobiology Laboratory and
> senior author of the SAGE KE report. "If so, these cells could have much 
> broader
> therapeutic applications than suggested by our earlier work."
> In 2001 Faustman's team found that a treatment designed to address the
> autoimmune reaction underlying type 1 diabetes actually cured the disease 
> in
> diabetic mice. Late in 2003 they reported the mechanism behind the earlier
> discovery: cells from the spleens of donor mice  intended to train the 
> diabetic
> animals' immune systems not to attack islet cells  were actually 
> producing new
> islets. The result suggested that the adult spleen  previously regarded 
> as
> playing a fairly minor role in regenerative medicine  might contain a
> population of potential islet stem cells.
> In their pursuit of that finding, the MGH researchers investigated the 
> possible
> presence of a protein called Hox11 in these cells. In mammals, Hox11 is a
> controller of key steps in embryonic development  including the formation 
> of
> the spleen  but it was not known to be present in adults under normal
> circumstances. In some other animals, however, the protein has an 
> intriguing
> function: when creatures like newts regenerate a lost limb or tail, 
> production
> of Hox11 is radically increased.
> As reported in their SAGE KE article, the MGH team did find that Hox11 was
> produced in the spleens of adult mice by the same cells that regenerated 
> the
> islets in the earlier study. They also found that these cells did not 
> produce a
> protein known to be associated with a cellular commitment to develop into 
> a
> particular type of tissue. Without that commitment, the splenic cells may 
> be
> able to differentiate into a wider variety of cells than can adult stem 
> cells
> from bone marrow, which do not produce Hox11.
> The researchers also note that the spleen develops from embryonic tissue 
> that
> is known not only to generate precursors to many types of blood cells, a
> function shared by the bone marrow, but potentially to form such diverse 
> organs
> as the small intestine, uterus, vascular system and lung. They theorize 
> that a
> pocket of these uncommitted cells might remain in the spleen though 
> adulthood.
> In addition to regeneration of islets, these cells might also produce bone 
> cells
>  suggested by findings from other researchers  or potentially even cells 
> of
> the nervous system, development of which depends on the correct production 
> of
> Hox11.
> "We know that if you have a major loss of blood, the spleen is turned on 
> to
> supplement the bone marrow in replenishing your blood supply. We may find 
> that
> the spleen kicks in to help with many more biological emergencies. What 
> has been
> considered a practically unnecessary organ may actually provide critical 
> healing
> cells," says Faustman, an associate professor of Medicine at Harvard 
> Medical
> School.
> She adds, "This data also shows the kind of payback that can come from 
> studies
> of lower animals like newts and sponges. Combining the knowledge of 
> Hox11's role
> in those animals with what we'd found about islet cell regeneration in 
> mice
> helped us find this previously unknown example of normal, controlled Hox11
> expression in an adult mammal."
> ###
>
> Co-authors of the SAGE KE report are first author Shohta Kodama, MD, PhD, 
> of
> the MGH Immunobiology Laboratory, and Miriam Davis, PhD, of George 
> Washington
> University. The group's research is supported by grants from the Iacocca
> Foundation. Founder Lee Iacocca is also spearheading an effort to raise 
> money
> for a clinical trial of the islet-regeneration technique in human 
> patients. For
> more information about this program, go to http://www.joinleenow.org.
> Massachusetts General Hospital, established in 1811, is the original and
> largest teaching hospital of Harvard Medical School. The MGH conducts the
> largest hospital-based research program in the United States, with an 
> annual
> research budget of more than $400 million and major research centers in 
> AIDS,
> cardiovascular research, cancer, cutaneous biology, medical imaging,
> neurodegenerative disorders, transplantation biology and photomedicine. In 
> 1994,
> MGH and Brigham and Women's Hospital joined to form Partners HealthCare 
> System,
> an integrated health care delivery system comprising the two academic 
> medical
> centers, specialty and community hospitals, a network of physician groups, 
> and
> nonacute and home health services.
>
>
> Rachel - "I would rather live my life as if there is a God, and die to 
> find out
> there isn't, than live my life as if there isn't, and die to find out 
> there is."
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> ---------------------------------
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