PTGFR and diabetes mellitus: Since diabetic nephropathy is also a microvascular complication of diabetes as retinopathy (Beckman & Creager, 2016) and excessive angiogenesis also occurs in diabetic nephropathy (Nakagawa et al, 2009), it is possible that the PGF2α/PTGFR axis may be involved in the pathogenesis of diabetic retinopathy.