FN1 and glomerulosclerosis: Finally, the advanced form of DKD displays prominent transforming growth factor (TGF‐β) up‐regulation, mesangial expansion and glomerulosclerosis.5 Indeed, TGF‐β1 increases extracellular matrix accumulation through the stimulation of collagen IV and fibronectin production,6 resulting in interstitial fibrosis and glomerular sclerosis.