In addition, the expression of mitochondrial stimulating PGC-1α, and mitochondrial functional proteins mitochondrially encoded cytochrome c oxidase II & -IV (MTCO2, MTCO4) were all significantly decreased in primary ASMCs of COPD patients when compared with controls (45.6%, 69.4%, and 66.1%, respectively, Figure 1B). Here, MT-CO2 is linked to chronic obstructive pulmonary disease.