the Battle against Parkinson’s disease
Christine Probst: #53, December 12, 2006
Parkinson’s disease (PD) is a chronic and progressive condition that affects more
than 2% of people over the age of 65 (1).
PD is caused through the decay of
dopamine producing neurons in the substantia nigra of the brain stem (2).
of life among PD patients is compromised by symptoms such as tremor, rigidity,
bradykinsia (slowness of movement) and postural instability.
to partially renew mobility are currently available, no cure to this disease has been
However, scientists are hopeful that stem cell research will lead to an
Through past experimentation, in vitro differentiation and
proliferation of embryonic stem cells into dopamine producing neurons has been
Still, a plethora of scientific as well as political obstacles are yet to be
Fluctuations in the U.S. government have made it nearly impossible to
secure steady financial grants, as this medical research has become entangled with
the abortion debate (4).
Recently, individual states have taken the initiative to
support stem cell research.
Californians voted yes on proposition 71, which secured
$3 billion in financial aid for future stem cell research (6).
With this money, an
expected “gold rush” of scientific breakthroughs regarding the treatment of
debilitating diseases such as Parkinson’s, Alzheimer’s and diabetes is expected (2,4).
Whether or not this is the case, this initiative serves as a beacon of hope for both
scientists and patients (2).
What Are Stem Cells?
By definition, stem cells are primitive,
undifferentiated cells with the ability to
replicate or differentiate into specialized
Also, stem cells are capable of
dividing themselves for long periods of
time; whereas specialized cells found the
heart or nervous system rarely reproduce
This is because differentiated cells
can only undergo a limited number of
divisions before dying, a discovery made
by Leonard Hayflick in 1965 (9).
Stem cells fall into three major
categories: determined stem cells,
totipotent stem cells, and pluripotent
Determined stem cells are
cells in which the genetic potential is
limited, and can only differentiate into
some types of cells.
cells are only found in the embryo, and
they can generate all types of cells
within an organism.
cells have all the same capabilities as
totipotent cells, yet they are unable to
reproduce the stem cells found during
early embryonic stages (7).
All tissues contain a stem cell
compartment that produces cellular
offspring that differentiate into all tissue
These cells are extremely
important in maintaining the
homeostasis within different organs, as
they can replace damaged or lost cells.
Stem cell depletion, due to disease or