Ask
Dr. Beristain
Question & Answers with Dr. Xabier Beristain=
Neurology
What is the effect of cholesterol medications
(“statins”) in PD?
“Statins”=
are a family
of cholesterol-lowering agents that include the following drugs: lovastatin
(Mevacor®), fluvastatin (Lescol®), simvastatin (Zocor®),
atorvastatin (Lipitor®), pravastatin (Pravachol®), rosuvastatin
(Crestor®). These drugs are “wonder drugs” in many ways as =
they
do not only reduce cholesterol, but also have been shown to help stabilize
atherosclerotic plaques (a.k.a. hardening of the arteries), and potentially
decrease the risk for Alzheimer’s disease and may even help people wi=
th
multiple sclerosis (MS). Unfortunately for PD, the information is somewhat
conflicting. Some reports sug=
gest
that these drugs may cause parkinsonian symptoms while others suggest a
protective effect against PD. Apparently statins are capable of decreasing =
the
amount of coenzyme Q10 that is naturally present in the body. However, stat=
ins
also inhibit the activation of a protein in the body called Ras, which is
involved in the production of several inflammatory chemicals. In animal models of PD inflammatio=
n is
present and improves when given statins. No clear recommendation is availab=
le
at this point although some experts do advocate taking supplements of coenz=
yme
Q-10 (Co-Q-10) if you’re already taking a statin or are in need of on=
e.
What is the status of GDNF studies and the poten=
tial
to improve PD?
The glial cell line-d=
erived
neurotrophic factor (GDNF) is a naturally occurring protein that stimulates=
the
growth and regeneration of dopamine–producing brain cells (neurons).
Initial experiments in animal were very promising, showing not only improve=
ment
of parkinsonian symptoms in these animals, but also increased numbers of
dopamine–making neurons. Initial studies in humans using intraventric=
ular
delivery of GDNF were disappointing. Later, GDNF was evaluated by continuous
infusion into specific areas of the brain with clear benefit in a small stu=
dy
of 5 patients. More data was needed and a larger study was conducted, but t=
his
larger study did not show clear efficacy according to Amgen, the biotech
company sponsoring the study. Some experts in PD did agree with this
interpretation of the data while others criticized it and requested further
testing of the compound. In addition, there was some concern regarding safe=
ty
and the development of antibodies in patients exposed to GDNF that may have
blocked its effect. Autopsy data of a patient exposed to GDNF delivered by
catheter into the brain has shown increased dopamine fibers and this was li=
nked
to this patient’s clinical benefit. The whole case has been very murky
with litigation against Amgen reported by 60
Minutes on CBS. Will we have another trial on GDNF? Time will tell.
What is Lewy Body Disease?
Everybody has heard a=
bout
Alzheimer’s disease, the leading cause of dementia, but many people h=
ave never
heard of Lewy body disease (LBD), which is likely the second cause of demen=
tia
affecting as many as 20% to one third of the patients with dementia. LBD patient typically pr=
esent
with parkinsonian symptoms, hallucinations, cognitive fluctuations and extr=
eme
sensitivity to drugs to treat PD and antipsychotic medications. Despite
features that do not fit into a diagnosis of Alzheimer’s disease, many
LBD patients are labeled as “Alzheimer” or as
“Parkinson” as there is some overlap with the “garden var=
iety”
of PD. Patients with LBD very often have stiffness, slowness and postural/g=
ait
abnormalities, but not much of a tremor. They also do experience visual
hallucinations, diminished attention, but not significant memory trouble, at
least not in the beginning. Fluctuation in mental status in which they may =
be
“out of it” for hours or days for no obvious reason is also com=
mon,
while other days may look very lucid. The cognitive problems do start earli=
er
in LBD, typically within one year of the onset of Parkinson symptoms, a fea=
ture
that can help us distinguish them from PD patients who develop dementia. LBD
also tends to progress quicker than PD and Alzheimer’s disease. Regar=
ding
treatment, some of the Alzheimer’s medications do help LBD, however PD
medications very often cause marked hallucinations even at the smallest dos=
es,
making treatment very challenging.
What is “freezing” and how do you tr=
eat
it? &nbs=
p;
Freezing refers to th=
e sudden
difficulty to start or continue movement, typically affecting the legs when=
starting
to walk or during walking; the legs seem to “get stuck”, frozen=
on
the spot. This typically last for a few seconds, but may be longer. Freezing may happen either when the
Parkinson medication is working or when it’s not working (a.k.a. the
“on freezing” and the “off freezing” respectively).=
It
can be triggered or worsened by activity or anxiety, among other potential
causes. If freezing happens on the “off” state increasing the
“on” time helps; however the “off freezing” is hard=
to
treat as typically it does not respond to levodopa or other PD drugs and
actually can get worse with PD medications. Very often using
“tricks” to overcome freezing is the way to handle these events:
stepping over a beam of laser light, marching to a song, stepping over mark=
s on
the floor, and walking sideways are among many tricks people has tried to
overcome freezing. Not every trick works for everybody and the trick may lo=
se
its effectiveness over time.