Modifiable Innate Biology within the Gut-Brain Axis for Alzheimer's Disease

Abstract

Alzheimer's disease (AD) is a prototypical inflammation-associated loss of cognitive function, with approximately 90% of the AD burden associated with invading myeloid cells controlling the function of the resident microglia. This indicates that the immune microenvironment has a pivotal role in the pathogenesis of the disease. Multiple peripheral stimuli, conditioned by complex and varied interactions between signals that stem at the intestinal level and neuroimmune processes, are involved in the progression and severity of AD. Conceivably, the targeting of critical innate immune signals and cells is achievable, influencing immune and metabolic health within the gut-brain axis. Considerable progress has been made, modulating many different metabolic and immune alterations that can drive AD development. However, non-pharmacological strategies targeting immunometabolic processes affecting neuroinflammation in AD treatment remain general and, at this point, are applied to all patients regardless of disease features. Despite these possibilities, improved knowledge of the relative contribution of the different innate immune cells and molecules comprising the chronically inflamed brain network to AD pathogenesis, and elucidation of the network hierarchy, are needed for planning potent preventive and/or therapeutic interventions. Moreover, an integrative perspective addressing transdisciplinary fields can significantly contribute to molecular pathological epidemiology, improving the health and quality of life of AD patients. This review is intended to gather modifiable immunometabolic processes based on their importance in the prevention and management of AD.

Keywords: Alzheimer’s disease; immunonutrition; innate immunity; microglia.

Figure 1

Schematic representation of physiological and biochemical pathways to approach the modifiable factors influencing innate immunity within the gut–liver–brain axis for Alzheimer’s disease prevention and/or treatment. TLR4, innate immune Toll-like receptor (TLR)-4; HDL, high-density lipoprotein; LDL, low-density lipoprotein; LXs, lipoxygenase interaction products.