Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

Abstract

The world is projected to experience an approximate doubling of atmospheric CO₂ concentration in the next decades. Rise in atmospheric CO₂ level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO₂ level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O₂ consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to longevity of animals will become very crucial challenge to biologists of the present millennium.

Keywords: Reactive oxygen species, Redox regulation, Oxidative stress, Survivability, Climate change, Disease susceptibility, Global warming, Longevity, Thermal stress

Core tip: Oxidative damages, generated by reactive oxygen species induce aging in cells via several senescence markers. Thermal stress under global warming can elevate oxidative damages with alleviated redox capacity in animals. Protein misfolding may also occur in animals under such conditions. Elevated temperature may also make the animals susceptible to diseases that are aggravated under thermal stress. Oxidative stress (OS) and disease susceptibility may push the animals to age faster under thermal stress. We propose a perspective by drawing relationships among rise in habitat temperature, OS, protein misfolding, disease susceptibility, aging and longevity in both poikilotherms and homeotherms.