The ratio of endothelial cells to intramural pericytes (E/IMP) in retinas of diabetic patients and in retinas from various nondiabetic disease groups has been studied. The results show a specific and highly significant loss of pericytes in diabetes, regardless of age. Loss of intramural pericytes in diabetes is associated with an increase in ghost cells, shunt vessels, and the number of microaneurysms.
Speiser P, Gittelsohn AM, Patz A. Studies on Diabetic RetinopathyIII. Influence of Diabetes on Intramural Pericytes. Arch Ophthalmol. 1968;80(3):332-337. doi:10.1001/archopht.1968.00980050334007