Exposure to cold increases life expectancy

A study shows that exposure to cold temperatures activates a system specialized in eliminating protein aggregates involved in cell aging.

It has been known for several years that a moderate decrease in body temperature is associated with longer lifespan. This is particularly striking in cold-blooded animals (poikilotherms) such as certain species of fish whose exposure to low temperature (15°C) significantly increases longevity.

This phenomenon is also observed in endotherms (warm-blooded animals) such as rodents: when mice are exposed to cold to lower their body temperature by 0.5°C, their lifespan is prolonged, while it decreases if we increase the temperature by 0.5°C. .

It is also possible that slight cooling of the body is beneficial to human health: for example, although normal body temperature has long been assumed to be 37°C (with variations of fractions of degrees during the day), recent data suggest that lower This temperature has decreased by about 0.03 degrees Celsius every decade since the Industrial Revolution and is now about 36.6 degrees Celsius.

It is suggested that this woman, which can reduce the risk of chronic infections due to a better treatment of infections and the use of anti-inflammatories, to contribute to long-term observation in a course of 150 Last few years. ⁽¹⁾

Cellular senescence

To better understand how cold affects longevity, German researchers looked at protein aggregates that accumulate inside cells during aging.

These aggregates, resulting from defects in the three-dimensional conformation of proteins that make them insoluble, are highly toxic to the cell and over time cause loss of function in the affected organs. ⁽²⁾

This is particularly striking for neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, or amyotrophic lateral sclerosis (ALS) (known as Lou Gehrig's disease or Charcot's disease), all of which result from the buildup of abnormal combinations of certain proteins.

Since cells contain an enzyme system specialized in getting rid of these aggregates (proteasomes), they wanted to know whether cold activates this proteasome and makes it possible to get rid of these aggregates to protect the cell from its toxicity.

This appears to be the case indeed. ⁽³⁾

In an animal model with aggregates typical of Huntington's disease or amyotrophic lateral sclerosis, lowering the temperature from 20 to 15°C results in activation of the proteasome and complete elimination of these aggregates that are associated with increased longevity.

A similar phenomenon was observed when human cells derived from an amyotrophic lateral sclerosis patient were exposed to a temperature of 36°C, suggesting that the mechanism for eliminating defective proteins that can be activated by cold is very ancient and has been conserved during evolution.

Cleaning the cell

The human body temperature is maintained constant by a highly sophisticated control system, and it is clearly not possible to lower body temperature over long periods of time.

On the other hand, an interesting observation from the study is that it would be possible to circumvent this limitation: the researchers actually observed that even at normal temperature (37°C), we can stimulate the elimination of toxic aggregates by increasing the ratio of protein levels ( It is called PSME3) involved in proteasome activation.

By developing treatments capable of recreating this phenomenon, we will not only be able to slow down the central process associated with biological aging, but above all we will be able to cleanse the cell of toxic aggregates responsible for many serious diseases, especially at the neurological level.

♦ (1) Protsev M. et al. Decreased human body temperature in the United States since the Industrial Revolution. Elevy 2020:9:e49555.

♦ (2) Quanalo Contreras K et al. Extensive accumulation of misfolded protein aggregates during normal aging and senescence. Front. Aging Neuroscience. 2022; 14:1090109.

♦ (3) Lee HJ et al. Cold temperature prolongs life and prevents disease-associated protein accumulation through proteasomes induced by PA28y. nat aging 2023; 3: 546-566.