Of the apolipoprotein (ApoE) ?4 allele are at increased risk of the development of late onset Alzheimer's disease (AD), develop AD at an earlier age and experience a more severe cognitive decline and shorter survival time. The ?4 allele has been linked to the severity of the hippocampal atrophy and pathological changes in the cerebral cortex. ?2 allele is thought to exercise protection against the disease.
"Atrophy of the hippocampus, a region of the brain crucial is a common feature of the display for storage, although it can be demonstrated in the asymptomatic persons as well as healthy adults carrier of the ?4 ApoE allele", said Andy Simmons, PhD, of the Department of neuroimaging of the Institute of Psychiatry of at King's College London. "If young people manifest early changes genetically at risk for AD an important question for the procedures or treatments designed to slow or the progression of the disease keeps interested."
To resolve the question, 1412 teenagers underwent MRI imaging and had tested blood samples for DNA analysis to determine their ApoE status. "In contrast to some recent studies no hippocampal volume differences between carrier and carrier of the ApoE-?4 all Elle observed", said Dr. Simmons. The investigators also other possible changes, such as hippocampal asymmetry or saw gene dose-dependent effects on volume, but could find no associations with genetic status.
In addition to structural changes in patients with AD show in the brain usually an increase in the brain strain of amyloid-ß (insoluble) peptides and a decrease in the cerebrospinal fluid (CSF) concentration of insoluble peptides. Similar changes can be found in almost all people with mild cognitive impairment risk conversion to AD. "This changes the earliest diagnostic tools in AD, dar", explains Professor Dr. med. Piotr Lewczuk, head of the laboratory of clinical neurochemistry, and neurochemical dementia diagnosis at the University Clinic for Psychiatry and psychotherapy, Universittsklinikum Erlangen, Friedrich-Alexander University Erlangen Board. Because to a certain extent, also changes the concentrations of insoluble peptide in the blood are observed, his research group investigates differences in the plasma levels of insoluble peptides among young adults e4, e3 and e2 providers.
To determine whether these changes are associated AD available at an early age before clinical symptoms are visible, investigators measured insoluble peptide concentration in the plasma of 175 cognitively normal young adults. 40 employees (22.9%) had at least one e4 allele and were the e3/e3 genotype had "endangered" for AD, 111 (63.4%) and were called "neutral" and 24 (13.7%) in the "protected: Group had at least one e2 allele."
The investigators measured four insoluble peptide and determined that no significant differences in any of the insoluble peptide plasma levels were found between the three genetic groups.
"The lack of differences of the insoluble concentration reported in this study between the groups with and without increased genetic risk for AD does not mean that the ongoing preclinical Neurodegeneration in all young subjects, can be completely excluded", says Dr. Lewczuk. He also notes that approximately 40% of AD patients of not bearing the e4 allele are. He considers, however, that findings of hippocampal volume and its study of plasma concentrations set Dr. Simmons insoluble near, that the AD-suggestive changes maybe 20-30 years before the onset of clinical symptoms, but probably not before start most.