“…Of the 268 potentially relevant records identified in the initial search, 43 studies were deemed eligible for a qualitative analysis. Overall, this systematic review included data obtained from 28 in vivo studies performed on research animals [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ], 11 in vitro studies [ 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ], 3 studies conducted both in vitro and in vivo [ 69 , 70 , 71 ], and 1 clinical study performed in patients with COPD and then conducted ex vivo [ 72 ] ( Table 2 ).…”