Connecting sugar and fibrosis: Diabetes as a hidden player in rheumatoid arthritis-associated interstitial lung disease

Figure 1 The metabolic-pulmonary-autoimmune axis linking rheumatoid arthritis, interstitial lung disease, and type 2 diabetes mellitus. 1: Interleukin-6, tumor necrosis factor-α, interleukin-1β, hyperglycemia and advanced glycation end-products; 2: Genetic susceptibility and environmental exposures trigger pulmonary epithelial injury, autoantigen release, immune activation, inflammation and fibroblast proliferation, and fibrosis; 3: Non-enzymatic glycation, endothelial damage, activation of profibrotic mediators, systemic inflammation, and metabolic stress. RA: Rheumatoid arthritis; T2DM: Type 2 diabetes mellitus; ILD: Interstitial lung disease.