Granulation tissue: a new model for studies of vascular complications of diabetes

New vessels and type I collagen formed in the diabetic milieu differ markedly from vessels and collagen formed in nondiabetic animals. The vessels in diabetic animals are permeated by albumin much more readily than normal and the collagen is much more extensively crosslinked than normal. This is the first animal model in which increased vascular permeability analogous to that observed in human diabetics can be readily produced and quantified. Two important implications of these observations are: 1) vascular and connective tissue constituents formed in the diabetic milieu are functionally and structurally compromised and 2) injury of any kind which leads to proliferative responses and increased turnover of molecular constituents of vessels may increase the rate of development and progression of "diabetic" vascular disease.