From gerontology to geroscience: a synopsis on ageing

Biological ageing can be tentatively defined as an intrinsic and inevitable degradation of biological function that accumulates over time at every level of biological organisation from molecules to populations. Senescence is characterised by a progressive loss of physiological integrity, leading to impaired function and increased vulnerability to death. With advancing age, all components of the human body undergo these cumulative, universal, progressive, intrinsic and deleterious (CUPID) changes. Although ageing is not a disease per se, age is the main risk factor for the development of a panoply of age-related diseases. From a mechanistic perspective, a myriad of molecular processes and components of ageing can be studied. Some of them seem especially important and they are referred to as the hallmarks of ageing. There is compelling evidence that senescence has evolved as an emergent metaphenomenon that originates in the difficulty in maintaining homeodynamics in biological systems. From an evolutionary perspective, senescence is the inevitable outcome of an evolutionarily derived equilibrium between the amount of resources devoted to somatic maintenance and the amount of resources devoted to sexual reproduction. Single-target, single-molecule and disease-oriented approaches to ageing are severely limited because they neglect the dynamic, interactive and networking nature of life. These limitations notwithstanding, many authors promote single-target and disease-oriented approaches to senescence, e.g. repurposed drugs, claiming that these methods can enhance human health and longevity. Senescence is neither a disease nor a monolithic process. In this review, the limitations of these methods are discussed. The current state of biogerontology is also summarised.

If ageing is a disease, then life is also a disease

Ageing is distinct from a disease. Sound arguments have been adduced to explain that senescence cannot be understood as a pathological process. Nevertheless, this distinction is believed to be artificial (Holliday 1995), and other eminent researchers argue that the senescence-pathology dichotomy is also misleading. Recently, it has been suggested that ageing should be classified as a complex pathological syndrome or a ‘pre-disease’ that is treatable. Proponents of this new paradigm argue that: (i) modern evolutionary theory predicts that ‘although organismal senescence is not an adaptation, it is genetically programmed’, (ii) ‘insofar as it is genetically determined, organismal senescence is a form of genetic disease’ (Janac et al. 2017) and (iii) ‘ageing is something very much like a genetic disease: it is a set of pathologies resulting from the action of pleiotropic gene mutations’ (Gems 2015). Also new generations of researchers, free of these traditional shackles, come with the belief that it is time to classify ageing as a disease, as the distinction between normal dysfunction and abnormal dysfunction is not completely clear and should be abandoned. Although they marshal their arguments in a convincing manner, persuasive counterarguments can be mounted. Here, the senescence-pathology dichotomy is critically discussed. A deeper analysis of this subject reveals the underlying problem of undefined terminology in science.

Contemporary views on human aging and longevity

Aging is currently stimulating intense interest of both researchers and the general public. In developed countries, the average life expectancy has increased by roughly 30 years within the last century, and human senescence has been delayed by around a decade. Although aging is arguably the most familiar aspect of human biology, its proximate and ultimate causes have not been elucidated fully and understood yet. Nowadays there are two main approaches to the ultimate causes of aging. These are deterministic and stochastic models. The proximate theories constitute a distinct group of explanations. They focus on mechanistic causes of aging. In this view, there is no reason to believe that there is only one biological mechanism responsible for aging. The aging process is highly complex and results from an accumulation of random molecular damage. Currently, the disposable soma theory (DST), proposed by Thomas Kirkwood, is the most influential and coherent line of reasoning in biogerontology. This model does not postulate any particular mechanism underpinning somatic defense. Therefore, it is compatible with various models, including mechanistic and evolutionary explanations. Recently, however, an interesting theory of hyper-function of mTOR as a more direct cause of aging has been formulated by Mikhail Blagosklonny, offering an entirely different approach to numerous problems and paradoxes in current biogerontology. In this view, aging is quasi-programmed, which means that it is an aimless continuation of developmental growth. This mTOR-centric model allows the prediction of completely new relationships. The aim of this article is to present and compare the views of both parties in the dispute, based on the results of some recent experimental studies, and the contemporary knowledge of selected major aspects of human aging and longevity

On the doorstep to senility: physical changes, health status and well-being in midlife

The movement of the baby boomers into the middle ages made the 45–65 age cohort the largest and the fastest growing segment of population in the first decade of the 21st century. This demographic expansion will have multiple consequences for ageing society. This paper aimed to provide an overview on biology of midlife transition. Physical characteristics, midlife-specific morbidity and mortality were described with focus to sexual dimorphism in physique and gender gap in mortality and morbidity. These characteristics made midlife a separate and unique stage of life. In-depth knowledge of this life stage may be useful in identifying and solving problems of ageing individuals and population.