Welten Angelique G A, Zareie Mohammad, van den Born Jacob, ter Wee Piet M, Schalkwijk Casper G, Driesprong Bas A J, Mul Frederik P J, Hordijk Peter L, Beelen Robert H J, Hekking Liesbeth H P
Department of Molecular Cell Biology and Immunology, VU University Medical Center, FdG, Postbus 7057, 1007 MB Amsterdam, The Netherlands.
Nephrol Dial Transplant. 2004 Apr;19(4):831-9. doi: 10.1093/ndt/gfh024.
Recurrent infections in peritoneal dialysis (PD) patients may alter the abdominal wall resulting in an impairment of its dialysis capacity. In this study we investigated both in vitro and in vivo the effects of mesothelial exposure to dialysis fluids on the migration of neutrophils and their capacity to clear a bacterial infection.
First, we evaluated neutrophil migration in an in vitro transwell model for the peritoneal membrane with monolayers of primary human mesothelial cells (MC) on the lower side and primary human endothelial cells (EC) on top of the same transwell membrane, upon exposure of MC to PD fluid (PDF)-derived components. In addition to this in vitro model, we combined chronic peritoneal exposure to PDF with a peritoneal infection model in the rat. We investigated the kinetics of the chemokine response, neutrophil recruitment and bacterial clearance.
Known chemoattractants, such as fMLP and IL-8, strongly increased neutrophil migration across both cell layers in the in vitro model of the peritoneal membrane. Pre-incubation of the MC layer for 48 h with 55 mM glucose, a combination of two glucose degradation products, methylglyoxal and 3-deoxyglucosone, or conventional dialysis fluid (1:4 dilution), however, did not change the IL-8-induced migration of neutrophils. In concert with this finding we demonstrated an unchanged MC expression of ICAM-1 and VCAM-1 after these pre-treatments. Unexpectedly, chronic i.p. exposure to conventional PDF or a recently developed lactate/bicarbonate-buffered PDF in a rat peritoneal exposure model strongly hampered the chemokine response upon bacterial challenge. Nevertheless, neutrophil recruitment and bacterial clearance were effective and did not differ from rats not pre-exposed to PDF.
We conclude that exposure of MC to PDF does not hamper the recruitment of functional neutrophils upon challenge.
腹膜透析（PD）患者反复感染可能会改变腹壁，导致其透析能力受损。在本研究中，我们在体外和体内研究了间皮细胞暴露于透析液对中性粒细胞迁移及其清除细菌感染能力的影响。
首先，我们在体外Transwell模型中评估中性粒细胞迁移，该模型用于模拟腹膜，在Transwell膜的下侧有原代人腹膜间皮细胞（MC）单层，在同一Transwell膜的顶部有原代人内皮细胞（EC），使MC暴露于腹膜透析液（PDF）衍生成分中。除了这个体外模型，我们还将大鼠长期腹膜暴露于PDF与腹膜感染模型相结合。我们研究了趋化因子反应、中性粒细胞募集和细菌清除的动力学。
已知的趋化剂，如fMLP和IL-8，在腹膜体外模型中强烈增加中性粒细胞跨两层细胞的迁移。然而，用55 mM葡萄糖、两种葡萄糖降解产物甲基乙二醛和3-脱氧葡萄糖醛酮的组合或传统透析液（1:4稀释）对MC层预孵育48小时，并没有改变IL-8诱导的中性粒细胞迁移。与此发现一致，我们证明了这些预处理后ICAM-1和VCAM-1的MC表达没有变化。出乎意料的是，在大鼠腹膜暴露模型中，长期腹腔内暴露于传统PDF或最近开发的乳酸/碳酸氢盐缓冲PDF会强烈阻碍细菌攻击后的趋化因子反应。尽管如此，中性粒细胞募集和细菌清除是有效的，与未预先暴露于PDF的大鼠没有差异。
我们得出结论，MC暴露于PDF不会妨碍受到攻击时功能性中性粒细胞的募集。
