Renin-angiotensin-aldosterone system inhibitors, including angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARBs), are currently widely used in the prevention and treatment of cardiovascular diseases, while RAAS may promote the progression of COPD and pulmonary fibrosis by inducing the production and release of inflammatory factors and reactive oxygen species (104). The gene discussed is REN; the disease is chronic obstructive pulmonary disease.