Motivations and thoughts about aging

Aging can be defined in two (overlapping) ways: an increase in mortality, or a decrease in fitness and biological functions, with age. In this sense, it is one of the most familiar biological concepts: as children, we start observing its effects on older individuals, and as adults, we experience it ourselves.

At first sight, we could analogize it to the wearing of a machine due to its daily use. Nevertheless, understanding which gears are failing is challenging due to the complexity of the living machines. Indeed, most of the biological processes affect or are affected by aging. Consequently, a plethora of studies have been describing potential cellular or molecular causes over the years, which Medvedev tried to rationalize in the late 20th century. Even though modern approaches and technologies now allow a more systematic and comprehensive analysis of this phenomenon, the reason why most living organisms lose their homeostasis with time, remains a complex question.

Beyond the fundamental scientific question, aging is also a source of apprehension of humans at the individual scale. This is the case for at least 2500 years, with Herodotus reporting the existence of a mythological fountain of youth. This is understandable, even more nowadays in developed countries, where aging can be seen as the primary source of death.

At the society scale, aging is an increasingly important concern, for public health and demographic reasons, knowing that the world population is getting older (especially in wealthy countries).

Why? Because aging is the main risk and hazard factor of many diseases (cancer, cardiovascular diseases, age-related diseases like Alzheimer or Parkinson, etc), in addition to being the main driver of a general state of frailty. The COVID19 pandemic has been a blatant example of how an aging population can become a major problem.

Hence, understanding the origins and the molecular processes involved in this phenomenon is as interesting as it is important, from an individual and public health point of view.