Unraveling biomarkers in Parkinson’s disease: the role of Insulin-like growth factor-1 (IGF-1) and DAT imaging

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease, affecting up to 10 million individuals worldwide. Although symptomatic treatment ameliorates motor symptoms, currently there are no disease-modifying treatments. A biomarker is defined by the National Institutes of Health as “a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacological responses to a therapeutic intervention”. Thus, biomarkers include clinical data, measurements of biological samples (e.g., plasma, serum, cerebrospinal fluid) and application of brain imaging techniques to detect changes in brain structure and function. As for PD, biomarkers represent tools potentially suitable for either clinical or research settings and useful in predicting onset, confirming diagnosis, detecting progression and evaluating the response to disease-modifying treatments. In addition, biomarkers’ trends in different stages of disease may reflect the widespread neurochemical and neuroanatomical changes that occur throughout the course of PD and, thus, possibly suggest new insights in the pathophysiological mechanisms underlying disease progression. The range of available biomarkers in PD is fast expanding and includes an increasing number of laboratory, clinical and imaging data. ... [edited by Author]