Alzheimer's disease is a dreaded
memory-robbing ailment caused by a progressive loss of brain function. Now
researchers in Switzerland, France, and the US have found a possible factor that
might contribute to development of the disease.
Apparently, a particular protein called apolipoprotein(a), or apo(a), is
associated with Alzheimer's, according to Dr. Vincent Mooser of CHUV University
Hospital in Lausanne, Switzerland, and colleagues.
Apolipoproteins are a class of proteins involved in the transport of various
fatty substances, called lipids, through the body. Elevated blood levels of the
apo(a) protein appears to increase the risk of Alzheimer's disease in some
individuals and lower the risk in others, according to a report in the April 4th
issue of the Annals of Internal Medicine.
Mooser and colleagues looked at 285 patients with Alzheimer's disease and
296 people without the disorder.
The investigators found that those who had high levels of apo(a) and
specific gene linked to Alzheimer's disease -- known as apolipoprotein E4
(apoE4) -- were more likely to have the ailment than those with lower levels.
Those who were over age 80 and did not carry the apoE4 gene were actually less
likely to have Alzheimer's disease if they had high blood levels of apo(a).
ApoE4 has clearly been shown to increase Alzheimer's risk. In the new study,
60% of people with Alzheimer's had ApoE4 compared with just 25% of people
without the disorder.
Because apo(a) bears some "similarities" to apoE4, the researchers theorized
that apo(a) might have some influence on the occurrence of Alzheimer's.
The findings suggest that apo(a) may act to "amplify the effect of apoE"
increasing the risk of Alzheimer's disease in apoE4 carriers and protecting
against Alzheimer's in non-apoE4 carriers, Mooser noted.
The current study findings could have considerable impact in terms of
diagnosis and treatment of Alzheimer's disease, according to Mooser. It may
eventually be possible to predict who will get the disease based on the
concentration of apo(a) and which apoE gene variant is present in a given
individual.
In addition, Mooser pointed out, "apo(a) might constitute a novel target in
our fight against Alzheimer's disease, either to protect against the disease
before it is clinically apparent, or to treat (the disease)."
He notes that the study was conducted largely in white Europeans and may not
be applicable to all ethnic groups. The findings need to be repeated with
further study, he cautioned.
The study was funded by the Swiss Foundation for Scientific Research, the
Placide Nicod and Octave Foundation for Clinical Research in Lausanne, and
INSERM/Institut Pasteur de Lille, France.
