Abstract
Hypertonic Na+ accumulation in peripheral tissues is a recently described phenomenon: it has been associated with ageing, hypertension, diabetes, chronic kidney disease and heart failure, but its clinical meaning has yet to be determined. This concept conflicts with the classic physiological paradigm of constant balance between salt intake and excretion, and its water-independent nature is still a matter of debate.We developed a theoretical model explaining changes in the chemical composition of tissues as a function of extracellular volume fraction and excess extracellular fluid, i.e. oedema. The model suggests that the proportional increase in absolute Na+ content and concentration due to different degrees of oedema is higher than the parallel increase in water content, thus making Na+ a more sensitive index to detect this oedema.Our model would explain some of the recent findings of high tissue Na+ content in pathological conditions. More importantly, it prompts the reappraisal of tissue Na+ analysis from being a topic of niche interest to a potential diagnostic tool with broad applicability in the investigation of subclinical systemic and localized oedema.
Highlights
Hypertonic Na+ accumulation in peripheral tissues is a recently described phenomenon: it has been associated with ageing, hypertension, diabetes, chronic kidney disease and heart failure, but its clinical meaning has yet to be determined
Classic physiology advocates the ultimate achievement of a constant balance between salt intake and excretion
Over the last few years work by Titze and his collaborators has highlighted the phenomenon of hypertonic sodium (Na+) accumulation in peripheral tissues
Summary
Hypertonic Na+ accumulation in peripheral tissues is a recently described phenomenon: it has been associated with ageing, hypertension, diabetes, chronic kidney disease and heart failure, but its clinical meaning has yet to be determined. This concept conflicts with the classic physiological paradigm of constant balance between salt intake and excretion, and its water-independent nature is still a matter of debate. We challenged the above model by simulating the effect of adding a fixed and biologically plausible moiety of fluid (e.g. 1%, 2.5% or 5%), equal in composition to the extracellular Na+-rich solution, to the tissues (i.e. oedema) This shifted the curves up for Na+ and down for K+, as expected from the equivalent of a global increase in ECV% (Figure 1, left panel, closed symbols for 5% oedema).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
