TNF and chronic obstructive pulmonary disease: Blervaque et al. discovered an impaired pericyte coverage of muscle capillaries in patients of mild-to-moderate COPD (Blervaque et al., 2020); this pericyte impairment may be due to inflammation, as both IL-1β and TNF-ɑ levels are increased in the serum of COPD patients (Pinto-Plata et al., 2007; Zou et al., 2017).