Nutrients, Microglia Aging, and Brain Aging

Abstract

As the life expectancy continues to increase, the cognitive decline associated with Alzheimer's disease (AD) becomes a big major issue in the world. After cellular activation upon systemic inflammation, microglia, the resident immune cells in the brain, start to release proinflammatory mediators to trigger neuroinflammation. We have found that chronic systemic inflammatory challenges induce differential age-dependent microglial responses, which are in line with the impairment of learning and memory, even in middle-aged animals. We thus raise the concept of “microglia aging.” This concept is based on the fact that microglia are the key contributor to the acceleration of cognitive decline, which is the major sign of brain aging. On the other hand, inflammation induces oxidative stress and DNA damage, which leads to the overproduction of reactive oxygen species by the numerous types of cells, including macrophages and microglia. Oxidative stress-damaged cells successively produce larger amounts of inflammatory mediators to promote microglia aging. Nutrients are necessary for maintaining general health, including the health of brain. The intake of antioxidant nutrients reduces both systemic inflammation and neuroinflammation and thus reduces cognitive decline during aging. We herein review our microglia aging concept and discuss systemic inflammation and microglia aging. We propose that a nutritional approach to controlling microglia aging will open a new window for healthy brain aging.

The effects of strength training on cognitive performance in elderly women

“… 41 As shown by several authors, the regular intake of particular micronutrients, such as omega 3 fatty acids, antioxidants, and flavonoids, could improve cognitive capacities in a chronic exposure mode, and delay the identification of the initial symptoms of neurodegenerative diseases. 42 On the other hand, low levels of such micronutrients in the subjects’ diet could drastically limit the acquired cognitive benefits from the strength training protocol applied here. 43 Further studies are necessary to elucidate the proper mechanisms and the close relationship between strength exercises and positive cognition responses in elderly population, especially regarding nutrition.…”

Thiamine Deficiency and Neurodegeneration: the Interplay Among Oxidative Stress, Endoplasmic Reticulum Stress, and Autophagy

“…Reversely, oxidative stress can also induce neuroinflammation. For example, there is increasing evidence that activated microglia produce excessive ROS during aging and hypoxia, resulting in the nuclear factor- κ B-dependent excessive production of proinflammatory mediators, such as interleukin-1 β , tumor necrosis factor- α , and interleukin-6 [85]. …”

A Clinical Review of the Consequences of Anesthesia and Surgery in the Elderly Brain: "The Dark Side of the Moon"

“…Aging itself creates glial al-terations, and the cause of the transition from normal aging glia to pathologic glia remains unclear. It is suspected that events during an individual's early life, including infection, stress, and nutrition, can impact immune reactivity within the brain and cause subsequent exaggerated glial activation called "glial priming" for the remainder of life, thereby altering cognition and increasing the risk of neuroinflammatory disorders, POCD, and Alzheimer's disease (20). In rats made vulnerable by infection early in life, even aging has been shown to impact glial reactivity (18,19).…”

“…(46). Because chronic systemic inflammation promotes aging of glia through excessive neuroinflammation, it is argued that antioxidant nutrients may be beneficial for preventing aging of glia, thereby improving cognitive functions (20). Hypothetically, environmental stimuli (toxins, drugs of abuse, dietary fatty acids) might also trigger neurodegeneration via inflammation in long-term outcomes (19).…”