Plant polyphenols as inhibitors of NF-КB induced cytokine production : a potential anti-inflammatory treatment for Alzheimer’s disease?

Alzheimer's disease (AD) is a neurodegenerative disorder that impacts the daily lives of many sufferers through memory loss as well as behavioral and cognitive changes. AD is the most common form of dementia. One in ten people over the age of 65, and around half of those over 85 have AD. AD can be divided into familial (early-onset) and sporadic (late-onset) cases, with the familial form (<1%) linked to mutations in three major genes (amyloid precursor protein, presenilin-1 and 2), and the sporadic form (>99% of cases) caused by a variety of genetic (e.g., apolipoprotein E), metabolic and environmental factors. The AD brain is characterized macroscopically by cortical atrophy, caused by degeneration of the cholinergic axonal arborisation and shrinkage of the dendritic tree. Microscopically, amyloid beta peptide deposits (senile plaques) and neurofibrillary tangles are present in affected areas (Gil-Bea et al., 2012). AD is also characterized by chronic neuroinflammation, driven by activation of astroglia and microglia (Rosenblum, 2014). In addition, levels of pro-inflammatory mediators or cytokines which include chemokines, interferons, interleukins, lymphokines, and tumor necrosis factors are elevated in the brains of patients with AD (Latta et al., 2014). Furthermore, nuclear translocation of NF-κB and STAT-1α, transcription factors involved in pro-inflammatory gene expression, indicates the presence of a sustained pro-inflammatory process (Lawrence, 2009).