Interstitial Sodium in Heart Failure: Proteoglycans and Glycosaminoglycans
Proteoglycans are the major structural components of the interstitium of different tissues and the first endothelial layer (the endothelial glycocalyx). They consist of multiple glycosaminoglycans (GAGs) attached to a linking protein. GAGs are linear polymers of disaccharide units that are modified by sulfation and/or acetylation and/or deacetylation and have fixed negative charges in the form of carboxyl (COO−) and sulfate (SO3−) groups. The polyanionic nature of the GAG network leads to electrostatic interactions with different molecules, particularly sodium (Na+) cations.