TNF and peripheral arterial disease: Other inflammation-indicating biomarkers, such as IL-8, pentraxin-3 (PTX-3), neutrophil gelatinase-associated lipocalin (NGAL), calprotectin, or tumor necrosis factor (TNF)-α, have also shown their potential in PAD diagnosis, among which PTX-3 and TNF-α were also associated with PAD severity [133,135,143,151].