TNF and peripheral arterial disease: ELISA assessment of the supernatants of myotubes derived from patients with no PAD, showed increased expression of IL-6 (median, 178 pg/mL; range, 133-269 pg/mL) and TNF-α (median, 199 pg/mL; range, 174-295 pg/mL) after simulated ischemia (P < .05; Mann-Whitney U test).