PIGF and non-proliferative diabetic retinopathy: Furthermore, the level of PIGF was significantly up-regulated in PDR patients (189.12±246.55 pg/ml) in comparison to the controls (18.10±77.28 pg/ml; p<0.001) as well as to DM (16.20±33.60 pg/ml; p<0.001) and to NPDR samples (22.00±43.19 pg/ml; p = 0.001; Fig 1B).