Use of haptoglobin and transthyretin as potential biomarkers for the preclinical diagnosis of Parkinson's disease

We have searched for potential biomarkers in the cerebrospinal fluid (CSF) and plasma in an animal model of Parkinson's disease induced by inflammatory challenge. To achieve this, either unilateral or bilateral intranigral injection of lipopolysaccharide (LPS) was performed. CSF proteins were first analyzed either by 2D electrophoresis and MALDI-TOF at days 1 and 10 after the lesion to discern between potential prognosis and diagnosis protein markers. Most significant changes from this analysis were early increases of haptoglobin, transthyretin and different spots further identified as prostaglandin D synthase in response to LPS. These markers were then analyzed by western blotting in CSF and plasma using specific antibodies from samples obtained in animals receiving either LPS in substantia nigra or hippocampus and 6-OHDA in the medial forebrain bundle. This analysis confirmed the early increases of haptoglobin and transthyretin in response to intranigral injection of LPS or 6-OHDA in the bundle in plasma and CSF. We discuss the potential use of both biomarkers for the early diagnose of Parkinson's disease.