The intersection between toxicology and aging research: A toxic aging coin perspective

Abstract

We are imminently faced with the challenges of an increasingly aging population and longer lifespans due to improved health care. Concomitantly, we are faced with ubiquitous environmental pollution linked with various health effects and age-related diseases which contribute to increased morbidity with age. Geriatric populations are rarely considered in the development of environmental regulations or in toxicology research. Today, life expectancy is often into one’s 80s or beyond, which means multiple decades living as a geriatric individual. Hence, adverse health effects and late-onset diseases might be due to environmental exposures as a geriatric, and we currently have no way of knowing. Considering aging from a different perspective, the term “gerontogen” was coined in 1987 to describe chemicals that accelerate biological aging but has largely been left out of toxicology research. Thus, we are challenged with a two-faced problem that we can describe as a “toxic aging coin”; on one side we consider how age affects the toxic outcome of chemicals, whereas on the other side we consider how chemicals accelerate aging (i.e. how chemicals act as gerontogens). Conveniently, both sides of this coin can be tackled with a single animal study that considers multiple age groups and assesses basic toxicology of the chemical(s) tested and aging-focused endpoints. Here, I introduce the concept of this toxic aging coin and some key considerations for how it applies to toxicology research. My discussion of this concept will focus on the brain, my area of expertise, but could be translated to any organ system.

Relationships between Effects of Ag Nanoparticles and Ag Salt on Behavioral and Cognitive Functions of Mice and Ageing

“…Let us consider Ag+ influence on mice in the same vein. The data shows the absence of the influence of Ag+ exposure to younger mice if we compare them with the intact ones (Control 3) ( Figures 11,13,14,16,18,20,22,24 SM). Table 6 demonstrates differences in behavior between intact mice and Ag + elder mice.…”

“…From the one side we consider how age affects the toxic outcome of chemicals, whereas from the other side we consider how chemicals accelerate aging (i.e. how chemicals act as gerontogens) [18]. It can be proved by the facts that aged organisms are at higher risks and more subject to negative actions of toxins [19].…”

Among Gerontogens, Heavy Metals Are a Class of Their Own: A Review of the Evidence for Cellular Senescence

“…Compounding this aging issue, we are faced with global environmental pollution of innumerable chemicals that threaten our health—a separate crisis that challenges aging health in two key ways, which we refer to as a “toxic aging coin” [ 3 ]. On the heads side of this toxic aging coin, we consider how life stage (e.g., juvenile vs. middle-aged vs. geriatric) impacts the toxic effects of chemicals.…”