Effect of ECM density in lymphatic vessel cytokine secretion. a) schematic of the culture conditions and experimental timeline. b) pro-inflammatory cytokine and chemokine concentrations for vessels cultured in ld and hd collagen matrix. c) IL-6 cytokine concentration in a range of collagen I density matrices (3, 4, 5 and 6 mg/ml). (n =4, pooled samples over 2 days from at least 6 lumens). *p ≤ 0.05, **p ≤ 0.01, ****p ≤ 0.0001.