DPP4 and diabetes mellitus: Factors with increased expression: Female sex, estrogen levels, younger age*, nasal and bronchial epithelial cells with age, mechanical ventilation with age, post-MI x 4 weeks, heart failure, renal proximal tubule cells, renal glomerular podocytes, pancreatic islet cells, controlled diabetes (1/2), Type 2 pneumocytes, COPD, chronic tobacco exposure, e-cigarettes, alcohol consumption, atopic asthma, ACEi, ARBs, MRAs, statins, GLP-1 receptor agonists, DPP4, NSAIDs*.