Growth factors and cytokines/chemokines as surrogate biomarkers in cerebrospinal fluid and blood for diagnosing Alzheimer's disease and mild cognitive impairment.

Alzheimer's disease (AD) is a severe chronic neurodegenerative disorder of the brain. A probable diagnosis of AD can be obtained by cerebrospinal fluid levels of 3 biomarkers: beta-amyloid (1-42), total tau and phospho-tau181. Researchers are interested in finding additional biomarkers in CSF to improve the specificity and sensitivity of diagnosis, including also other forms of dementia, such as mild cognitive impairment (MCI). In addition, less invasive diagnostic methods using blood or blood-derived cells are being investigated. This mini-review (in concert with the other reviews of this special issue) summarizes the usefulness of growth factors and cytokines/chemokines as putative surrogate biomarkers for diagnosing AD and MCI in CSF and blood. Briefly, the expression levels of growth factors and cytokines/chemokines are very heterogenous, indicating the pathological diversity of these diseases. At present, no single growth factor or cytokine alone stands out as a useful biomarker for diagnosing AD or MCI. However, the combined "patients profile signature" of several selected growth factors and/or cytokines/chemokines may allow to diagnose AD and MCI with higher selectively and specificity. Copyright 2009 Elsevier Inc. All rights reserved.