INS and type 1 diabetes mellitus: The extracellular volume in human islets under resting conditions has been estimated to be about 14% of the total islet volume [20], and a fivefold increase in the accumulation of hyaluronan and hyaladherins in the pericapillary space between the two basal membranes in insulin-containing islets has been reported in subjects with recent-onset T1D when compared to non-diabetic controls [21].