As IPF lung fibroblasts with ASS1 deficiency require the uptake of extracellular arginine for survival due to an inability to endogenously synthesize arginine, arginine deprivation strategies, including arginine-free diet and arginine deiminase (ADI) which degrades extracellular arginine, demonstrate antifibrotic effects on reducing collagen content and fibrotic lesions in the lung of mice exposed to bleomycin [16]. The gene discussed is ASS1; the disease is idiopathic pulmonary fibrosis.