Alzheimer's disease (AD) is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to function independently. Despite the significant effort to understand the basic biology of the disease and pharmaceutical advances to develop drugs, there is no effective therapy available to treat AD or slow the disease progression.

β-amyloid accumulation outside brain cells and abnormal accumulations of tau protein inside neurons are taught to be two main changes in the brain that lead to AD. Progressive accumulation of β-amyloid interferes with the neuron-to-neuron communication at synapses, contributing to neural cell death. Also, tau tangles block the transport of nutrients and other essential molecules into the neurons. Many molecules have been shown to inhibit amyloid aggregation. The anti-amyloidogenic activity of trehalose was confirmed in both in vitro and in vivo studies and its inhibitory effects on β-amyloid formation in AD have also been demonstrated. Trehalose is a non-toxic disaccharide and no dose-dependent adverse effects were seen in any of the safety studies. It can act as a chemical chaperone and stabilizes the natively folded structure of protein and also trehalose has been identified as an autophagy inducer and promotes the clearance of aggregated proteins. Therefore, trehalose could be a valuable candidate for the treatment and prevention of amyloid-related disease. Based on the proposed hypothesis, this study aim to investigate the potential efficacy of trehalose administration in patients with AD.

Purpose of the study: A randomized, triple-blind, pilot clinical trial has been designed to evaluate the effectiveness of trehalose on reducing the symptoms in AD patients. Study intervention: twenty patients with Alzheimer's disease were randomly divided into an intervention and a control group. Trehalose will be administrated intravenously (15 g/week) for 12 weeks in the intervention group and the control group will be received normal saline as a placebo.

Inclusion Criteria:

• Mini-Mental State Examination (MMSE) score range from 10 to 23
• Not having other cognitive disorders

Exclusion Criteria:

• MMSE score higher than 23 or lower than 10
• The presence of other cognitive disorders which will be evaluated by clinical assessment and brain imaging
• The presence of factors affecting cognitive impairment such as depression
• Vascular dementia and Lewy body dementia
• Previous history of head trauma
• Use of alcohol and other drugs that affect cognitive functioning