C1QTNF9 and diabetic retinopathy: The results of an experimental study also revealed that CTRP9 could augment cell viability and reduce high glucose‐induced oxidative stress and apoptosis via AMPK/Nuclear factor erythroid‐derived 2‐like 2 (NFE2L2) signalling in ARPE‐19 cells, a retinal pigment epithelial (RPE) cell line, indicating CTRP9 as a promising therapeutic target in diabetic retinopathy.86