Alcohol, aging, and innate immunity

Abstract

The global population is aging: in 2010, 8% of the population was older than 65 y, and that is expected to double to 16% by 2050. With advanced age comes a heightened prevalence of chronic diseases. Moreover, elderly humans fair worse after acute diseases, namely infection, leading to higher rates of infection-mediated mortality. Advanced age alters many aspects of both the innate and adaptive immune systems, leading to impaired responses to primary infection and poor development of immunologic memory. An often overlooked, yet increasingly common, behavior in older individuals is alcohol consumption. In fact, it has been estimated that >40% of older adults consume alcohol, and evidence reveals that >10% of this group is drinking more than the recommended limit by the National Institute on Alcohol Abuse and Alcoholism. Alcohol consumption, at any level, alters host immune responses, including changes in the number, phenotype, and function of innate and adaptive immune cells. Thus, understanding the effect of alcohol ingestion on the immune system of older individuals, who are already less capable of combating infection, merits further study. However, there is currently almost nothing known about how drinking alters innate immunity in older subjects, despite innate immune cells being critical for host defense, resolution of inflammation, and maintenance of immune homeostasis. Here, we review the effects of aging and alcohol consumption on innate immune cells independently and highlight the few studies that have examined the effects of alcohol ingestion in aged individuals.

Effect of age, sex, and season on the variation in blood analytes of a clinically normal ex situ population of killer whales (Orcinus orca)

“…Cornell noted a similar decrease in WBCs with age in killer whales. In humans and other mammals, advanced age alters both the innate and adaptive immune systems . Immune senescence starts as the thymus shrinks, eventually resulting in a decline of naïve T cells.…”

“…In addition, many of the myeloid‐derived, innate effector functions including phagocytosis are downregulated by aging as well. In humans, immune senescence leads to both decreased responses to acute infections and poor development of immunologic memory . These and other age‐related changes involving the immune system predispose the elderly to infectious diseases, cardiovascular diseases, atherosclerosis, autoimmune diseases, neoplasia, anemia, degenerative diseases including metabolic syndrome, and organ failure, such as renal failure.…”

Age is the work of art? Impact of neutrophil and organism age on neutrophil extracellular trap formation

“…And, as such, it is also important how NET release changes with age. Especially, the world is undergoing a shift in demographics with low birth rates and aging of populations (Boule and Kovacs 2017 ). Independently of the age of mothers, not only fewer babies are being born but also many of them are born preterm and therefore they are more likely to become ill or die, as preterm infants are more vulnerable to infection (Urquhart et al 2017 ).…”

“…In line with this, the risk of severe sepsis in neonates increases dramatically with decreasing gestational age (Sperandio et al 2013 ). On the other hand, the global population is aging and the number of indivuduals older than 65 years will double by 2050 (Boule and Kovacs 2017 ). Elderly people are more susceptible to infection due to inflamm-aging or immunosenescence, i.e., the age-related dysfunction of the immune system but they also develop chronic inflammatory states (Boe et al 2017 ).…”

Role of Alcohol Drinking in Alzheimer’s Disease, Parkinson’s Disease, and Amyotrophic Lateral Sclerosis

“…Mild to moderate regular consumption might be beneficial [10]. However, chronic and excessive alcohol drinking leads to social, economic and multi-organ problems, including an altered neurological system [11], liver disease [12], cardiotoxicity [13], psychiatric disorders [14], cancer [15], and endocrine [16], microbiome [14] and immunity disruption [17]. [19] APOE4: epsilon 4 allele of the apolipoprotein E; BMI: Body mass index; BMAA: β-methylamino-L-alanine.…”