Biological markers in Alzheimer disease

Diagnosis of Alzheimer disease (AD) is based on clinical features and confirmed only at pathological brain examination. However, since markers of pathogenic mechanisms have been demonstrated in biological fluids and in peripheral tissues, several of them have been proposed as in vivo diagnostic tools. Their importance is underscored by the need to discriminate among various types of dementia and by the evidence that effective treatments should start at early phases of disease or even at preclinical stages. Apart from genetic mutations responsible for the few cases of familial AD, so far no single biological test has reached a reliable degree of sensitivity and specificity for a definite in vivo diagnosis, to detect susceptible individuals at preclinical stage or patients suitable for appropriate drug therapies. More recently, however, combinations of various biological markers have shown higher reliability as diagnostic tools. For these reasons the research on biological markers in AD is presently blooming and the Italian Interdisciplinary Network on Alzheimer Disease (ITINAD, www.itinad.com), a scientific team of clinicians and researchers, which brings together neurologists, psychiatrists, geriatricians, pharmacologists, and molecular biologists, devoted its second monothematic symposium to this theme. The first part of the meeting covered the results of a multi-center study, sponsored by the Italian Ministry of Education and Research, which investigated the interactions of various pathogenic events (amyloid processing, mitochondrial dysfunction, oxidative stress, excitotoxicity) in peripheral tissues obtained from AD patients.