Sanders N N, De Smedt S C, Van Rompaey E, Simoens P, De Baets F, Demeester J
Faculties of Pharmacy, Veterinary Medicine, and Medicine, Ghent University, Ghent, Belgium.
Am J Respir Crit Care Med. 2000 Nov;162(5):1905-11. doi: 10.1164/ajrccm.162.5.9909009.
Cystic fibrosis (CF) is characterized by the presence of a viscoelastic mucus layer in the upper airways and bronchi. The underlying problem is a mutation in the gene encoding the cystic fibrosis transmembrane conductance regulator protein. Clinical studies of gene transfer for CF are ongoing. For gene delivery to the airways of CF patients to be effective, the mucus covering the target cells must be overcome. We therefore examined the extent to which CF sputum presents a physical barrier to the transport of nanospheres of a size comparable to that of lipoplexes and other transfection systems currently being clinically evaluated for CF gene therapy. We observed that an extremely low percentage of nanospheres (< 0.3%) moved through a 220-microm-thick CF sputum layer after 150 min. The largest nanospheres studied (560 nm) were almost completely blocked by the sputum, whereas the smaller nanospheres (124 nm) were retarded only by a factor of 1.3 as compared with buffer. Surprisingly, the nanospheres diffused significantly more easily through the more viscoelastic sputum samples. We hypothesize that the structure of the network in sputum becomes more macroporous when the sputum becomes more viscoelastic. Sputum from a patient with chronic obstructive pulmonary disease retarded the transport of nanospheres to the same extent as did CF sputum. When directly mixed with CF sputum, recombinant human deoxyribonuclease I moderately facilitated the transport of nanospheres through CF sputum.
囊性纤维化（CF）的特征是在上呼吸道和支气管中存在粘弹性粘液层。根本问题是编码囊性纤维化跨膜传导调节蛋白的基因发生突变。针对CF的基因转移临床研究正在进行中。为了使向CF患者气道的基因递送有效，必须克服覆盖靶细胞的粘液。因此，我们研究了CF痰液对大小与目前正在CF基因治疗中进行临床评估的脂质体和其他转染系统相当的纳米球运输构成物理屏障的程度。我们观察到，150分钟后，极低百分比的纳米球（<0.3%）穿过了220微米厚的CF痰液层。所研究的最大纳米球（560纳米）几乎完全被痰液阻断，而较小的纳米球（124纳米）与缓冲液相比仅被延迟了1.3倍。令人惊讶的是，纳米球在粘性更大的痰液样本中扩散得明显更容易。我们推测，当痰液变得更具粘性时，痰液中网络结构会变得更具大孔性。慢性阻塞性肺疾病患者的痰液对纳米球运输的阻碍程度与CF痰液相同。当与CF痰液直接混合时，重组人脱氧核糖核酸酶I适度促进了纳米球通过CF痰液的运输。
