title: Aging as a consequence of intracellular water volume and density.
abstract: Aging is the result of a gradual failure of physiological and/or biochemical pathways that culminates with the death of the organism. Until now, the causative factors of aging are elusive, despite the increasing number of theories that try to explain how aging initiates. Interestingly, aging cells show an increase in intracellular water volume, but this fact is barely explored in aging studies. All cells have a crowded cytoplasm, where the high concentration and proximity of macromolecules create an environment that excludes many small molecules, including water. In this crowded environment, water can be found in two states termed low density water (LDW), which shows low reactivity and has an ice-like structure, and high density water (HDW) that has a disorganized structure and is highly reactive. LDW predominates in a macromolecular crowded environment, while HDW is found only in microenvironments within cytoplasm. In this sense, we hypothesized that the failure in the water homeostasis mechanisms with time changes the equilibrium between LDW and HDW, increasing the concentration of intracellular HDW. Being reactive, HDW leads to the generation of reactive oxygen species and disturbs the crowded cytoplasm environment, resulting in a diminished efficiency of metabolic reactions. Noteworthy, the cell becomes less prone to repair damage when the concentration of HDW increases with time, resulting in aging and finally death. Interestingly, some biological mechanisms (e.g., anhydrobiosis) reduce the concentration of intracellular water and prolong the life of cells and/or organisms. In this sense, anhydrobiosis and related biological mechanisms could be used as a platform to study new anti-aging therapies.
authors: Centro de Biotecnologia da Universidade Federal do Rio Grande do Sul, Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, RS, Brazil. diegobonatto@gmail.com
authors: Diego
authors: D
authors: Bonatto
authors: Bruno César
authors: BC
authors: Feltes
authors: Joice de Faria
authors: Jde F
authors: Poloni
mesh_terms: D000375:Aging / Q000502:physiology*; D001834:Body Water / Q000737:chemistry* / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D042541:Intracellular Space / Q000502:physiology*; D008954:Models, Biological