Serum Leptin Levels in Patients with Alzheimer’s Disease

Introduction: Leptin receptors have been identified in many peripheral tissues as well as the CNS including thehippocampus, which is particularly vulnerable in Alzheimer’s disease (AD). Animal data shows that leptin may beimplicated in the pathophysiology of AD. The aim of this study was to examine if there is any differences in serumleptin levels between patients with AD and normal controls.Material and methods: Ninety patients with AD and 95 normal controls matched for age and gender wereincluded. The diagnosis of Alzheimer dementia was based on standard criteria provided by the ICD-10 system.Blood samples were frozen at -80oC until analysis. Leptin levels were measured using a human leptin enzymelinked immunosorbent assay (ELISA) kit.Differences in leptin levels were assessed between the two groups using the Mann–Whitney method. Linearregression analysis was also used to adjust for characteristics shown to be associated with leptin and cognitivedecline.Results: From the patients with AD, 74 were women and 16 were men (mean age 80.53±6.03, mean body weight71.49±8.33) and from the control group 78 were women and 17 men (mean age 79.27±6.86, mean body weight70.23±6.73). Linear regression revealed that the use of antipsychotic drugs was associated with serum levels ofleptin (p<0.001). Serum leptin levels were, also, significantly lower in patients with AD compared to normalcontrols (17.89±23.59 in AD patients vs 26.82±17.77 in normal controls, p<0.0001, Mann-Whitney U).Conclusion: Our study, in accordance with the findings of studies in animal models, provides evidence that leptinmay be implicated in the pathophysiology of AD.