A Fall for Stem Cells Injunction Halting Stem Cell Research Funds May Have Far-Reaching Consequences

(STEPHEN BROZAK and LARRY JINDRA, M.D. ABC News) There is some anticipation that this fall will be an important season for the debate on embryonic stem cell research. On Aug 30, 2010 a Washington, DC district judge (Lamberth), issued a temporary injunction halting all federal funding for basic research into embryonic stem cell technology. The injunction states there is a legitimate basis for arguing the matter in court. A full hearing will soon decide the final outcome. If the decision is upheld, federal funding for embryonic stem cell research will cease, in a similar manner to the previous funding moratorium on this research during the Bush administration.

According to this article, Judge Lamberth’s decision “reflects the lack of awareness in the U.S. around research and development of embryonic stem cells”. This statement was made because subsequent to the ruling, the price of numerous stem cell company stocks fell, including of companies working in the area of adult stem cells. These companies in no way should be affected by the controversy surrounding embryonic stem cells.

The article highlights the important difference between these two stem cell types. Embryonic stem cells are generated from a fertilized egg in vitro. These stem cells are highly undifferentiated and form tumors when administered into immune deficient mice called teratomas. The other type of stem cells, adult stem cells, are derived from sources such as bone marrow, menstrual blood, cord blood, placenta, and fat. These cells do not generated tumors and have been used therapeutically in the treatment of many diseases. To date, the only use of embryonic stem cells in humans has been by the company Geron that is generating oligodendrocytes from embryonic stem cells for use in the treatment of patients with spinal cord injury.

Geron has spend years trying to attain FDA approval for its approach. A temporary approval was granted under the Obama administration which was rapidly rescinded. Subsequently the trial was allowed to continue, however no data has been reported at the time of writing.

Adult stem cell companies include Osiris, who are working on bone marrow derived mesenchymal stem cells for treatment of heart failure, graft versus host disease, and Crohn’s Disease, Pluristem, who are working on placental mesenchymal stem cells for treatment of critical limb ischemia, and Medistem Inc, who are using menstrual blood derived Endometrial Regenerative Cells (ERC) for treatment of the same condition.

The authors of the article are Stephen Brozak, president of WBB Securities, an independent broker-dealer and investment bank specializing in biotechnology, medical devices and pharmaceutical research and Dr. Lawrence Jindra who is director of research for WBB Securities.

2010-08-27T16:43:49+00:00August 27th, 2010|Embryonic Stem Cells, News, Stem Cell Research|

Stem cells approved to treat ‘orphan’ disease

Stargardt’s Macular Dystrophy is the most common form of
genetic juvenile macular degeneration. Manifestation of the condition begins in
late childhood, leading to legal blindness. It is symptomatically similar to
age-related macular degeneration, and it affects approximately one in 10,000
children.  Olympic and Paralympic skier Brian McKeever is the best-known victim
of the disease, which has no treatment.  Today the company Advanced Cell
Technology obtained "Orphan Drug Status" of use of its embryonic stem cell
derived product MA09-hRPE as a treatment for Stargardt’s disease. 

Orphan Drug Status is a mechanism the government uses to
promote interest of pharmaceutical in disease for which a small market exists. 
Typically to obtain this the target market must be less than 200,000 people in
the United States.  Orphan Drug Status allows a company to retain market
exclusivity for seven years, as well as allows for various clinical trial tax
incentives.

Human embryonic stem cells have been demonstrated to be
capable of giving rise to the cells that make up practically every tissue in the
body.  The ability of these cells to make anything from liver, to lung, to nerve
cells makes them attractive as sources of replacement tissues to biomedical
researchers. Last year the Obama Administration opened federal funding to
more-recent generations of such stem cells, and in January allowed research
funding to cells such as ACT’s, grown from a single cell clipped from an
early-stage embryo.

Designation of Orphan Drug Status is not approval of the
embryonic stem cell based product for sale, but only classifies the cells as a
product in development.  Approval of a drug, whether it is a chemical, a
biologic, or a cell, requires clinical trials in which safety and efficacy is
demonstrated.  The initial hurdle companies must pass is to obtain
Investigational New Drug status.  This was only granted to one embryonic stem
cell company, Geron, for use of their embryonic stem cell derived
oligodendrocytes for treatment of spinal cord injury.  The approval, however,
was rapidly retracted after additional preclinical data demonstrated development
of abnormal growths in treated animals.  Subsequent to IND approval companies
have to demonstrate safety in Phase I studies, efficacy in Phase II studies, and
double blinded efficacy in Phase III studies which usually involve numerous
clinical trial sites. 

The major problem with embryonic stem cell derived products
is the risk of tumor formation.  In general embryonic stem cells are defined by
the ability to form a type of cancer called teratoma.  These tumors are highly
aggressive and comprise numerous cells of the body.  When Advanced Cell
Technologies or Geron are differentiating retinal epithelia cells, or
oligodendrocytes, respective, they must demonstrate to the FDA that no
contaminating stem cells are present in the injection mixture that could
possibly lead to tumor formation.  Another drawback of embryonic stem cell
technology is that it is extremely difficult to selectively add new cells to the
area of injury.  Specifically, the de novo created functional body cells must be
capable of integrating into the existing cells and taking over their function. 
Optimization of these approaches requires understand the molecular cues involved
in natural stem cell differentiation into cells of the body.    Yet another
drawback is that embryonic stem cell lines are not patient-specific.  This
requires the use of immune suppression, which often comes with numerous side
effects. 

2010-05-03T17:53:30+00:00May 3rd, 2010|Embryonic Stem Cells, News, Stem Cell Research|

Butyrate Greatly Enhances Derivation of Human Induced Pluripotent Stem Cells by Promoting Epigenetic Remodeling and the Expression of Pluripotency-Associated Genes

Generation of inducible pluripotent stem cells (iPS) offers
the possibility of creating patient-specific stem cells with embryonic stem cell
therapeutic potential from adult sources.  Recently the main hurdle of iPS cell
generation, the need for introduction of oncogenes in the adult cells, has been
removed by use of chemical modulators as well as alternative non-cancer causing
genes.  Another drawback of creating iPS cells is the need for mass screening of
many transfected target cells before identification and extraction of the
correct cell can be made.  In the current paper the histone deacetylase
inhibitor butyrate was used to enhance potency of iPS generation in vitro. 
Histone deacetylase inhibitors are a type of compounds that decrease the density
of DNA in chromosomes.  By performing this function the DNA because more
amenable to reprogramming, in the sense that the cells can be coaxed to
de-differentiate with less effort.  Another histone deacetylase inhibitor,
valproic acid, which is used clinically to treat convulsions, has been shown to
increase the ability of blood making stem cells to self-replicate with higher
efficiency, which is a characteristic of earlier de-differentiation.    

In a recent paper it was demonstrated that temporary
treatment with butyrate increases efficacy of iPS generation by 15-51 fold using
two techniques that are commonly used for generation of these cells.  It was
demonstrated that in the presence of butyrate stimulation a remarkable (>100-200
fold) increase on reprogramming in the absence of either KLF4 or MYC transgene.

This suggests that butyrate may be a useful agent to
incorporate in the iPS generation protocols that are currently under
development.  Furthermore, butyrate treatment did not negatively affect
properties of iPS cell lines established. The generated iPS cell lines,
including those derived from an adult patient with sickle cell disease by two
methods show normal karyotypes and pluripotency.

To mechanistically identify molecular pathways of butyrate
enhancement of iPS generation, the investigators performed conducted genome-wide
gene expression and promoter DNA methylation microarrays and other epigenetic
analyses on established iPS cells and cells from intermediate stages of the
reprogramming process.

 By day 6-12 after exposing cells to butyrate, enhanced
histone 3 acetylation, promoter DNA demethylation, and the expression of
endogenous pluripotency-associated genes including DPPA2, whose over-expression
partially substitutes for butyrate stimulation is known.

According to Dr. Mali " Thus, butyrate as a cell
permeable small molecule provides a simple tool to further investigate molecular
mechanisms of cellular reprogramming. Moreover, butyrate stimulation provides an
efficient method for reprogramming various human adult somatic cells, including
those from patients that are more refractory to reprogramming
"

Methods of increasing efficacy of iPS generation have
included not only chemical manipulation but also starting from cell sources that
are generally considered more immature.  For example a previous study
demonstrated that mesenchymal stem cells create a much higher per-cell number of
iPS cells as compared to skin fibroblasts. 

One of the interesting points of this finding is that
butyrate may theoretically be useful at expanding potential of stem cells
already in an organism.  Since butyrate is used clinically for treatment of urea
cycle disorders and is non-toxic at pharmacological doses, it may be a good
candidate for expanding stem cells in vivo.  Manipulation of the stem cell
compartment by administration of therapeutic agents has already been performed
for mobilization, which has been published with the neutraceutical Stem-Kine

http://www.translational-medicine.com/content/pdf/1479-5876-7-106.pdf
.

The Senescence-Related Mitochondrial/Oxidative Stress Pathway is Repressed in Human Induced Pluripotent Stem Cells

Embryonic stem cells possess the ability to propagate in
tissue culture indefinitely.  This is different than differentiated cells, for
example, skin cells which can only multiple in tissue culture approximately 50
times before undergoing senescence.  The ability of embryonic stem cells to
escape senescence is related to expression of the protein telomerase.  Usually
when cells multiply the ends of the chromosomes, called telomeres, progressively
reduce in size.  When the telomeres become critically short, the gene p53 is
activated, which is involved in instructing the cells to stop multiplying and
exist in a semi-alive state called senescence.  Tumor cells and embryonic stem
cells escape senescence by expressing the enzyme telomerase.  This enzyme
essentially allows cells to repair their telomeres by progressively adding new
nucleic acids.  Although much is known about senescence or lack thereof in adult
cells and embryonic stem cells, little research has been performed in whether
inducible pluripotent stem cells (iPS) can also escape proliferative
senescence.  In a recent publication this question was examined.

In a similar manner to embryonic stem cells, iPS cells were
shown to express high levels of the enzyme telomerase, and propagation in tissue
culture was achieved up to 200 passages without senescence occurring. 
Furthermore the investigators studied the mitochondrial stress pathway.  It was
found that somatic mitochondria within human iPSCs revert to an immature
ESC-like state with respect to organelle morphology and distribution, expression
of nuclear factors involved in mitochondrial biogenesis, content of
mitochondrial DNA, intracellular ATP level, oxidative damage, and lactate
generation. When iPS cells were differentiated into adult cells, mitochondria
within iPSCs demonstrated maturation and anaerobic-to-aerobic metabolic
modifications. This same finding was observed in embryonic stem cells. 

These data suggest that iPS cells possess several important
properties similar to embryonic stem cells, which further supports the
possibility of interchangeably using ES and iPS cells for experimental purposes.
The next question is whether iPS cells may be generated in large quantities so
that their mitochondria may be transferred to aged cells. 

Another interesting finding in the current study is that
the metabolic pathway used by both iPS and embryonic stem cells is analogous to
that found in cancer cells.  Therefore it will be interesting to follow studies
using iPS as a model of cancer.

2010-03-03T19:18:55+00:00March 3rd, 2010|Embryonic Stem Cells, News, Stem Cell Research|

Fat May Serve a Purpose in Stem Cell Research

Scientist Dr. Joseph Wu at the Stanford University School
of Medicine has recently published a new and improved method to generate stem
cells "artificially".  For almost a decade there has been substantial
controversy regarding the use of embryonic stem cells, with the debate becoming
socially and politically focused as opposed to based on science: one camp
believing that embryonic stem cell research must be supported at all costs, the
other camp believing that adult stem cells can do anything that embryonic stem
cells can do, so there should be no research performed in this area.  This
debate became somewhat irrelevant when the Japanese group of Yamanaka discovered
a method of "dedifferentiating" adult cells into cells that appear at a
molecular and functional level similar to embryonic stem cells.  These
"artificial" stem cells, called inducible pluripotent stem cells (iPS) have
several unique properties:  They don’t need to be extracted from embryos; they
can be made from the same patient that they will be used on; and the methods of
manufacturing can be relatively standardized. 

To date these cells have been demonstrated to be capable of
generating not only every tissue in the body tested, but they also can improve
disease conditions in animal models ranging from heart attacks, to liver
failure, to bone marrow reconstitution.  Unfortunately the biggest problem with
iPS cells is that they are difficult to generate.  In order to understand this,
it is important to first mention how the cells are made.  Adult cells have the
same DNA blueprint as embryonic stem cells.  However in adult cells certain
portions of the DNA are not used to make proteins.  So in liver cells the DNA
that encodes for proteins found in the skin is "silenced" or "blocked" from
making proteins by various chemical modifications that occur as a cell is
maturing.  Embryonic stem cells are considered "blank slate" cells because the
DNA is capable of expressing every protein found in the body.  In order to make
an adult stem cell "younger" so as to resemble an embryonic stem cell, it is
necessary to somehow reprogram the DNA in order to allow it to express every
gene.  So how would one go about doing this? There is one biological condition
in which adult cells take the phenotype of younger cells.  This is in cancer. 
This is the reason why some types of cancer start expressing proteins that other
cells normally produce.  For example certain liver cancers can produce insulin,
even though liver cells do not produce insulin.  The concept that certain cancer
genes can evoke a "rejuvenation" of adult cells was used by Yamanaka as a
starting point.  His group found that if you insert the oncogene c-myc, together
with the stem cell genes Nanog, Oct-4, and SOX-2 skin cells will start to look
like embryonic stem cells.  If these cells are placed on top of feeder cells
then they can be expanded and used as a substitute for embryonic stem cells.

The current problem with wide-scale use of this approach is
that insertion of the various genes into the cells requires the use of viruses
that literally infect the cells with the foreign genes.  Not only can the
viruses cause cancer, but also the genes administered can cause cancer because
they are oncogenes.  The other hurdle is that generation of iPS cells is a very
inefficient process.  It takes approximately 2-3 months to generate stable
cells, and these cells are usually generated from approximately 1 out of
100-300,000 starting cells.  We previously discussed advances that allowed for
uses of non-hazardous means of inserting genes into cells to make iPS

http://www.cellmedicine.com/thomson-safer-ips.asp
, in this current article
another approach was described to increase efficacy.

Scientists used as starting population not skin cells,
which are considered substantially differentiated, but instead used fat derived
stem cells.  This type of stem cell is very much a mesenchymal stem cell

http://www.youtube.com/watch?v=qJN2RyBj78I
and possesses ability to
transform into different tissues already.  Thus by starting with a cell that is
already more "immature", scientists have been able to increase the rate of iPS
generation, as well as, alleviate the need for the oncogene c-myc.

Other approaches being investigated on increasing
generation of iPS cells include use of chemicals that affect the DNA structure
such as valproic acid.  This is interesting because simple administration of
valproic acid on bone marrow stem cells has been demonstrated to increase their
"stemness"

http://www.youtube.com/watch?v=3Hc4LCUOSiA
.

Although we are still far from the day when
individual-specific stem cells will be available for widespread use, we are
getting closer to this dream at a very fast pace.

2010-02-26T19:32:09+00:00February 26th, 2010|Adult Stem Cells, Embryonic Stem Cells, News, Stem Cell Research|