12 Hallmarks of Ageing

Ageing is a natural and progressive process which occurs in all living organisms. It is a multifactorial process, characterised by the deterioration of structure and functional capacities at the molecular, cellular, tissue and organismal levels. With ageing comes fragility and, as a consequence, an individuals’ susceptibility to both age-related disease and a reduced lifespan increases. However, it is possible to slow down, stop or even reverse the ageing process and improve our health-span.
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DNA

In recent years, ageing has started to be seen as a consequence of accumulated damage, waste products and toxins generated by our body’s essential metabolic processes. When we are young, our bodies can remove these waste products and our cells are constantly repairing and maintaining themselves. With time, however, they slow down, and we gradually accumulate damaged cells and lose our ability to replace them with new ones. The result? Ageing becomes the biggest risk factor for the development of age-related diseases. 

The 12 hallmarks of ageing are now generally accepted by the scientific community as the definitive features of ageing. These processes are interrelated and impact one another. There is a constant requirement for energy through and between the different parts of our body. It may well be that the hallmarks of ageing are interconnected to an energy supply and demand imbalance. This could be alleviated with a variety of lifestyle interventions that can provide restorative energy, promote our health, and increase our health-span. 

Genomic Instability

Over time, our DNA becomes damaged. The more DNA is damaged, the less cells can function correctly. Genomic instability is the appearance of high frequency mutations within the DNA, and is a characteristic of most cancer cells. 

Epigenetic Alterations

Our epigenome is the mechanism which regulates our genes’ activity, and during ageing it can become disorganised, modifying the activation of certain genes without changing the DNA sequence. Reprogramming the epigenome can extend lifespan. 

Telomere Attrition

The ends of our chromosomes, called telomeres, act as ‘lids’ to protect the DNA. These shorten and deteriorate as we age, leaving the DNA vulnerable to genomic instability and cell damage. 

Loss of Proteostasis

Proteins are essential for the proper functioning of our cells. The complex process of recycling these proteins – proteostasis – leaves some proteins behind, leading to a build up inside and out of the cells, causing dysfunction and damage. 

Mitochondrial Dysfunction

The body’s ‘generators’, mitochondria are found in huge numbers in every cell, except red blood cells. As we age, our mitochondria become damaged and dysfunctional, leaving cells lacking in energy.  

Deregulated Nutrient Sensing

Our metabolic pathways regulate how our cells respond to nutrition, with receptors gauging amino acids and glucose, for example. A surfeit of nutrients leads to overactivation of these pathways, accelerating ageing.  

Cellular Senescence

Formerly healthy cells, senescent cells have ceased dividing but resist dying, secreting inflammatory compounds which damage healthy surrounding cells. These so-called ‘zombie cells’ accumulate over time, compromising tissue function and leading to tissue and organ damage. 

Stem Cell Exhaustion

As a side effect of ageing, our stem cell numbers decline along with their capacity for renewal. As stem cells lead to the creation of blood cells, a depleted population leads to these losing their ability to recover from damage and replenish the vital organs. 

Altered Intercellular Communication

Our cells are constantly exposed to a huge range of signals which coordinate the various physiological functions of the body. Ageing cells increase their self-preserving signals which results in an increase in inflammatory signalling, causing cell damage. 

Microbiome Dysbiosis

The microbial diversity in the gut is essential for healthy digestive and immune systems. Dysbiosis – or disruption – of the microbiome can lead to dysfunction of these systems, and raised risk of disease and infection. 

Chronic Inflammation

Inflammageing is the chronic, low-level inflammation regarded as a biomarker of accelerated biological ageing, usually affected by lifestyle. This inflammation can contribute to age-related diseases such as diabetes and cardiovascular disease. 

Disabled Macroautophagy

Cells perform a process of self-cleaning called autophagy. This activity declines with age, leading to a build-up of damaged and harmful cellular components which can have profound negative effects on health. 

Cells