I highlighted some parts but other parts are interesting too
https://www.sciencedirect.com/science/article/pii/S0735109714071782
Consequently, a large amount of Na+ is bound to GAGs, creating a microenvironment of hypertonic Na+concentration (19). However, the dense network exhibits a low compliance, secondary to its strong elastic and tensile force, thereby “pressing” fluid out. Importantly, disruption of bonds within GAGs or alterations in bound molecules will have significant structural and functional consequences for the proteoglycans 20, 21.
Interstitial Sodium
Sodium accumulates dynamically in interstitial glycosaminoglycan networks
The interstitium connects and supports tissues while serving as a transport medium for nutrients, waste products, and signaling molecules. GAGs are the main constituents of the interstitium of various tissues 22, 23, 24. Together with collagen and/or elastin fibers, they comprise the solid phase and determine the structure and compliance of the interstitium 22, 25. Because 1 GAG macromolecule can bind a large quantity of Na+cations, the interstitium can accumulate or buffer a high amount of Na+(Figure 1A) (26). Data from long-term balance studies in humans have confirmed that considerable amounts of Na+ accumulate in the interstitium, particularly in skin and muscle tissue, without compensatory water retention or changes in plasma Na+ concentration 11, 27, 28. Kopp et al. recently quantified Na+ concentrations in skin and muscle on the basis of 23Na-magnetic resonance imaging spectroscopy. Their data suggested that, in contrast to a very stable plasma Na+ concentration, the tissue Na+ content in humans is highly variable, and that these variations are not accompanied by changes in tissue fluid content 15, 29. As a consequence, in both normal circumstances and compensated HF states, interstitial GAG networks “smooth” fluctuations in plasma Na+concentrations, and therefore, conceal Na+ ions from the pituitaryosmoreceptors, preventing AVP release and thus preventing water retention. Moreover, because these secluded Na+ cations do not reach the renal nephron, they also escape renal regulatory function and are more difficult to remove from the body.
.........GAGs create a high osmotic pressure microenvironment (22). Therefore, subjects with a more dense interstitial GAG network—and consequently with a higher interstitial oncotic pressure (πI)—will have more filtration of plasma fluid over the capillary membrane into the interstitium. However, the limited elastic properties (and thus, low compliance) of the interstitial GAG network prevent fluid accumulation 33, 34. Small increases in interstitial fluid content lead to important increases in interstitial tensile stress. This forces interstitial fluid into the gaping lymphatic vessels......
https://www.sciencedirect.com/science/article/pii/S0735109714071782
Consequently, a large amount of Na+ is bound to GAGs, creating a microenvironment of hypertonic Na+concentration (19). However, the dense network exhibits a low compliance, secondary to its strong elastic and tensile force, thereby “pressing” fluid out. Importantly, disruption of bonds within GAGs or alterations in bound molecules will have significant structural and functional consequences for the proteoglycans 20, 21.
Interstitial Sodium
Sodium accumulates dynamically in interstitial glycosaminoglycan networks
The interstitium connects and supports tissues while serving as a transport medium for nutrients, waste products, and signaling molecules. GAGs are the main constituents of the interstitium of various tissues 22, 23, 24. Together with collagen and/or elastin fibers, they comprise the solid phase and determine the structure and compliance of the interstitium 22, 25. Because 1 GAG macromolecule can bind a large quantity of Na+cations, the interstitium can accumulate or buffer a high amount of Na+(Figure 1A) (26). Data from long-term balance studies in humans have confirmed that considerable amounts of Na+ accumulate in the interstitium, particularly in skin and muscle tissue, without compensatory water retention or changes in plasma Na+ concentration 11, 27, 28. Kopp et al. recently quantified Na+ concentrations in skin and muscle on the basis of 23Na-magnetic resonance imaging spectroscopy. Their data suggested that, in contrast to a very stable plasma Na+ concentration, the tissue Na+ content in humans is highly variable, and that these variations are not accompanied by changes in tissue fluid content 15, 29. As a consequence, in both normal circumstances and compensated HF states, interstitial GAG networks “smooth” fluctuations in plasma Na+concentrations, and therefore, conceal Na+ ions from the pituitaryosmoreceptors, preventing AVP release and thus preventing water retention. Moreover, because these secluded Na+ cations do not reach the renal nephron, they also escape renal regulatory function and are more difficult to remove from the body.
.........GAGs create a high osmotic pressure microenvironment (22). Therefore, subjects with a more dense interstitial GAG network—and consequently with a higher interstitial oncotic pressure (πI)—will have more filtration of plasma fluid over the capillary membrane into the interstitium. However, the limited elastic properties (and thus, low compliance) of the interstitial GAG network prevent fluid accumulation 33, 34. Small increases in interstitial fluid content lead to important increases in interstitial tensile stress. This forces interstitial fluid into the gaping lymphatic vessels......