Exploring the administration route of HGF-expressing adenoviral vector (Ad-HGF) and low but local HGF-expression plasmid vector with macroaggregated albumin/polyethyleneiminV(MAA-PEI) for the clinically effective HGF gene transfer therapy.

肝细胞生长因子(HGF)是一种多器官再生因子，具有抗凋亡、促血管生成、促增殖和形态形成等功能，不仅在肝脏发挥作用，而且在肾脏和肺中发挥作用。在本研究中，为了将HGF基因转移应用于急性肺损伤(ALI)和肺纤维化的临床治疗，我们探索了(1)在给药途径中使用高表达但有抗原性的腺病毒载体，(2)在小鼠模型中使用低表达但局部和非炎症性质粒载体。虽然气管内注射Ad-HGF可检测到高水平的HGF蛋白，但博莱霉素性ALI和纤维化持续存在，而HGF作用减弱。而静脉注射Ad-HGF虽然只有少量HGF进入肺内，但通过抑制肺泡上皮细胞的凋亡和转化生长因子-β的表达，博莱霉素所致的ALI和纤维化均受到抑制。将MAA-PEI导入HGF混合载体进行肺内局部表达，与裸质粒载体相比，表达效率提高了10倍(1 Ug)，表达持续时间延长了10天以上。此外，肺中HGF的浓度仅为Ad-HGF的千分之一，有效地抑制了博莱霉素所致的ALI和纤维化。综上所述，在博莱霉素诱导的ALI和纤维化模型中，非气管注射Ad-HGF可获得高水平的HGF表达和抑制肺部炎症反应，但HGF/MAA-PEI的局部性、非炎性和可重复性的特点为临床治疗ALI或纤维化提供了一种可能的途径。

Hepatocyte growth factor (HGF) is a multi-organ regeneration factor including the anti-apoptotic, angiogenic, proliferative, and morphogenic activity functioning not only in liver but kidney or lung. In the current investigation, in order to apply the HGF gene transfer in the clinical setting for acute lung injury (ALI) and lung fibrosis, we have explored (1) the use of high-expression but antigenic adenoviral vector in the context of administration route, and (2) the use of low-expression but local and non-inflammatory plasmid vector in mouse model. Although high HGF protein was detected by intratracheal Ad-HGF administration, the bleomycin induced ALI and fibrosis persisted with reduced HGF effect. In contrast, in spite of the fact that only fraction of HGF was delivered to the lung by the way of intraperitoneal of intravenous administration of Ad-HGF, the bleomycin induced ALI and fibrosis had been suppressed through repression of both alveolar epithelial cell apoptosis and TGF-b expression. When MAA-PEI was introduced to mix plasmid HGF vector for local HGF expression in the lung, the expression efficiency increased by 10 fold (1 ug plasmid) compared with naked plasmid vector, and the duration of HGF expression prolonged for more than 10 days. Furthemore the concentration of HGF in the lung was only one thousandth of the amount yielded by Ad-HGF, the bleomycin induced ALI and fibrosis was efficiently suppressed. Taken together, while high HGF expression and suppression of lung inflammation was obtained using non-tracheal Ad-HGF administration in the bleomycin induced ALI and fibrosis, local, non-inflammatory and repeatable feature of HGF plasmid/MAA-PEI indicates a possible modality for clinical application in ALI or fibrosis.