Distinct and early increase in circulating MMP-9 in COVID-19 patients with respiratory failure. Issue 3 (September 2020) - Ueland, T; Holter, JC; Holten, AR; Müller, KE; Lind, A; Bekken, GK; Dudman, S; Aukrust, P; Dyrhol-Riise, AM; Heggelund, L