O'Kane Cecilia M, McKeown Scott W, Perkins Gavin D, Bassford Chris R, Gao Fang, Thickett David R, McAuley Danny F
Respiratory Medicine Research Programme, Centre for Infection and Immunity, Queen's University, Belfast, United Kingdom.
Crit Care Med. 2009 Jul;37(7):2242-9. doi: 10.1097/CCM.0b013e3181a5506c.
Acute respiratory distress syndrome (ARDS) is characterized by alveolar-capillary barrier damage. Matrix metalloproteinases (MMPs) are implicated in the pathogenesis of ARDS. In the Beta Agonists in Acute Lung Injury Trial, intravenous salbutamol reduced extravascular lung water (EVLW) in patients with ARDS at day 4 but not inflammatory cytokines or neutrophil recruitment. We hypothesized that salbutamol reduces MMP activity in ARDS.
MMP-1/-2/-3/-7/-8/-9/-12/-13 was measured in supernatants of distal lung epithelial cells, type II alveolar cells, and bronchoalveolar lavage (BAL) fluid from patients in the Beta Agonists in Acute Lung Injury study by multiplex bead array and tissue inhibitors of metalloproteinases (TIMPs)-1/-2 by enzyme-linked immunosorbent assay. MMP-9 protein and activity levels were further measured by gelatin zymography and fluorokine assay.
BAL fluid MMP-1/-2/-3 declined by day 4, whereas total MMP-9 tended to increase. Unexpectedly, salbutamol augmented MMP-9 activity. Salbutamol induced 33.7- and 13.2-fold upregulation in total and lipocalin-associated MMP-9, respectively at day 4, compared with 2.0- and 1.3-fold increase in the placebo group, p < 0.03. Salbutamol did not affect BAL fluid TIMP-1/-2. Net active MMP-9 was higher in the salbutamol group (4222 pg/mL, interquartile range: 513-7551) at day 4 compared with placebo (151 pg/mL, 124-2108), p = 0.012. Subjects with an increase in BAL fluid MMP-9 during the 4-day period had lower EVLW measurements than those in whom MMP-9 fell (10 vs. 17 mL/kg, p = 0.004): change in lung water correlated inversely with change in MMP-9, r = -.54, p = 0.0296. Salbutamol up-regulated MMP-9 and down-regulated TIMP-1/-2 secretion in vitro by distal lung epithelial cells. Inhibition of MMP-9 activity in cultures of type II alveolar epithelial cells reduced wound healing.
Salbutamol specifically up-regulates MMP-9 in vitro and in vivo in patients with ARDS. Up-regulated MMP-9 is associated with a reduction in EVLW. MMP-9 activity is required for alveolar epithelial wound healing in vitro. Data suggest MMP-9 may have a previously unrecognized beneficial role in reducing pulmonary edema in ARDS by improving alveolar epithelial healing.
急性呼吸窘迫综合征（ARDS）的特征是肺泡-毛细血管屏障受损。基质金属蛋白酶（MMPs）与ARDS的发病机制有关。在急性肺损伤试验中的β受体激动剂研究中，静脉注射沙丁胺醇在第4天可降低ARDS患者的血管外肺水（EVLW），但对炎症细胞因子或中性粒细胞募集无影响。我们推测沙丁胺醇可降低ARDS患者的MMP活性。
通过多重微珠阵列法检测急性肺损伤研究中患者的远端肺上皮细胞、II型肺泡细胞和支气管肺泡灌洗（BAL）液上清中的MMP-1/-2/-3/-7/-8/-9/-12/-13，并通过酶联免疫吸附测定法检测金属蛋白酶组织抑制剂（TIMPs）-1/-2。通过明胶酶谱法和荧光因子测定法进一步检测MMP-9蛋白和活性水平。
到第4天时，BAL液中的MMP-1/-2/-3水平下降，而总MMP-9水平有升高趋势。出乎意料的是，沙丁胺醇增强了MMP-9的活性。与安慰剂组分别增加2.0倍和1.3倍相比，沙丁胺醇在第4天时使总MMP-9和脂质运载蛋白相关MMP-9分别上调33.7倍和13.2倍，p<0.03。沙丁胺醇不影响BAL液中的TIMP-1/-2。与安慰剂组（151 pg/mL，四分位间距：124 - 2108）相比，沙丁胺醇组在第4天时的净活性MMP-9更高（4222 pg/mL，四分位间距：513 - 7551），p = 0.012。在4天期间BAL液中MMP-9增加的受试者的EVLW测量值低于MMP-9下降的受试者（10 vs. 17 mL/kg，p = 0.004）：肺水变化与MMP-9变化呈负相关，r = -0.54，p = 0.0296。沙丁胺醇在体外可上调远端肺上皮细胞的MMP-9并下调TIMP-1/-2的分泌。抑制II型肺泡上皮细胞培养物中的MMP-9活性可减少伤口愈合。
沙丁胺醇在体外和体内均可特异性上调ARDS患者的MMP-9。MMP-9上调与EVLW降低有关。体外肺泡上皮伤口愈合需要MMP-9活性。数据表明，MMP-9可能通过改善肺泡上皮愈合在减少ARDS肺水肿方面具有先前未被认识到的有益作用。
