Alzheimer’s disease (AD), considered the most common type of dementia, is characterized by a progressive loss of memory, visuospatial, language and complex cognitive abilities. In addition, patients often show comorbid depression and aggressiveness. Aging is the major factor contributing to AD; however, the initial cause that triggers the disease is yet unknown. Scientific evidence demonstrates that AD, especially the late onset of AD, is not the result of a single event, but rather it appears because of a combination of risk elements with the lack of protective ones. A major risk factor underlying the disease is neuroinflammation, which can be activated by different situations, including chronic pathogenic infections, prolonged stress and metabolic syndrome. Consequently, many therapeutic strategies against AD have been designed to reduce neuro-inflammation, with very promising results improving cognitive function in preclinical models of the disease. The literature is massive; thus, in this review we will revise the translational evidence of these early strategies focusing in anti-diabetic and anti-inflammatory molecules and discuss their therapeutic application in humans. Furthermore, we review the preclinical and clinical data of nutraceutical application against AD symptoms. Finally, we introduce new players underlying neuroinflammation in AD: the activity of the endocannabinoid system and the intestinal microbiota as neuroprotectors. This review highlights the importance of a broad multimodal approach to treat successfully the neuroinflammation underlying AD.

Strong evidence indicates that insulin resistance contributes to the development of Alzheimer´s disease by promoting inflammation, oxidative stress, and blood vessel damage. Conversely, neuroinflammation induces insulin resistance by targeting insulin signaling molecules: the insulin receptor substrates 1 and 2 (IRS1/2). In addition, neuroinflammation is strongly linked to reduced levels of brain-derived neurotrophic factor (BDNF) expression. BDNF is a key factor for neuronal survival, and its expression is compromised in neurodegenerative disorders. In this study, we show that, in a triple-transgenic (3xTg) mice model of Alzheimer’s disease, the BDNF and IRS2 but not the IRS1 mRNA expression levels were reduced in the hippocampus, together with higher levels of TNFα, compared with wild-type mice. Subgroups of control and 3xTg mice received short and long treatments of Abscisic Acid (ABA), a phytohormone with anti-inflammatory and insulin-sensitizing capabilities. We found that the short ABA treatment can increase the IRS1 and IRS2 mRNA expression both in wild-type and 3xTg mice, concomitant with reducing pro-inflammatory cytokine TNFα in 3xTg mice. However, earlier, and thus longer treatments are required to rescue the BDNF mRNA levels. Our data strongly confirm that ABA administration is a potential treatment to prevent Alzheimer´s disease, via lowering neuroinflammation, potentially rescuing insulin signaling molecules and BDNF mRNA expression.