Leptin and adiponectin in plasma and CSF from Alzheimer's patients and normal controls

Abstract

Life style related diseases such as hypertension, diabetes, and dyslipidemia are reported to be a great risk for dementia (1). Adipocytokines released from fat tissue are supposed to be related to the etiology of Alzheimer's disease (AD). We here analyzed leptin and adiponectin in cerebrospinal fluid (CSF), serum and plasma from AD patients and normal controls (NC) and discussed how these adipocytokines could contribute to the pathomechanism of AD. AD patients and NCs were recruited in Tohoku University Hospital. The diagnosis of AD was based on NINCDS-ADRDA criteria. Cognitive functions were examined using MMSE and ADAS-Cog. All the samples were obtained from each fasted patient or NC. Leptin in serum, plasma and CSF was assayed using a sandwich ELISA system (R&D) and adiponectin was assayed in three multimer forms, high molecular weight (HMW), middle molecular weight (MMW), and low molecular weigh (LMW) using a sandwich ELISA system (Daiichi Pure Chemicals Co) (2). We succeeded in quantification of leptin and HMW, MMW and LMW of adiponectin in both human plasma and serum. The levels of leptin and each form of adiponectin were comparable between in plasma and in serum. However, it was difficult to analyze three forms of adiponecin in CSF because of their concentrations looked too low. The levels of Leptin and three forms of adiponectin in CSF are highly correlated to those in plasma in both ADs and NCs. It was suggested that the levels of leptin and total adiponectin in serum or plasma reflect the levels of these adipocytokines in CSF from AD and NCs. Therefore the levels in serum or plasma could estimate the intracerebral concentrations of these molecules. Comparison of the levels of leptin and adiponectin between ADs and NCs are now underway.