Section of Medical Biochemistry, Molecular Biology and Genetics, Department of Biomedical and Specialist Surgical Sciences, University of Ferrara, 44121 Ferrara, Italy.
Technische Universität Dresden, Research Center for Regenerative Therapies, 01307 Dresden, Germany.
Int J Mol Sci. 2019 Feb 14;20(4):817. doi: 10.3390/ijms20040817.
Several studies showed that hydroxyethyl starch (HES), a synthetic colloid used in volume replacement therapies, interferes with leukocyte-endothelium interactions. Although still unclear, the mechanism seems to involve the inhibition of neutrophils' integrin. With the aim to provide direct evidence of the binding of HES to neutrophils and to investigate the influence of HES on neutrophil chemotaxis, we isolated and treated the cells with different concentrations of fluorescein-conjugated HES (HES-FITC), with or without different stimuli (N-Formylmethionine-leucyl-phenylalanine, fMLP, or IL-8). HES internalization was evaluated by trypan blue quenching and ammonium chloride treatment. Chemotaxis was evaluated by under-agarose assay after pretreatment of the cells with HES or a balanced saline solution. The integrin interacting with HES was identified by using specific blocking antibodies. Our results showed that HES-FITC binds to the plasma membrane of neutrophils without being internalized. Additionally, the cell-associated fluorescence increased after stimulation of neutrophils with fMLP ( < 0.01) but not IL-8. HES treatment impaired the chemotaxis only towards fMLP, event mainly ascribed to the inhibition of CD-11b (Mac-1 integrin) activity. Therefore, the observed effect mediated by HES should be taken into account during volume replacement therapies. Thus, HES treatment could be advantageous in clinical conditions where a low activation/recruitment of neutrophils may be beneficial, but may be harmful when unimpaired immune functions are mandatory.
几项研究表明，羟乙基淀粉（HES）作为一种用于容量替代治疗的合成胶体，会干扰白细胞-内皮细胞相互作用。尽管其机制尚不清楚，但似乎涉及到中性粒细胞整合素的抑制。为了提供 HES 与中性粒细胞结合的直接证据，并研究 HES 对中性粒细胞趋化作用的影响，我们分离并以不同浓度的荧光素标记的 HES（HES-FITC）处理细胞，有或没有不同的刺激物（N-甲酰基-甲硫氨酸-亮氨酸-苯丙氨酸，fMLP，或 IL-8）。通过台盼蓝淬灭和氯化铵处理评估 HES 的内化。用 HES 或平衡盐溶液预处理细胞后，通过琼脂糖下趋化性测定评估趋化性。用特异性阻断抗体鉴定与 HES 相互作用的整合素。我们的结果表明，HES-FITC 结合到中性粒细胞的质膜上而不被内化。此外，在用 fMLP 刺激中性粒细胞后（<0.01），细胞相关荧光增加，但用 IL-8 则不会。HES 处理仅损害了对 fMLP 的趋化性，这主要归因于 CD-11b（Mac-1 整合素）活性的抑制。因此，在容量替代治疗期间应考虑到由 HES 介导的观察到的作用。因此，在可能需要低中性粒细胞激活/募集的临床情况下，HES 治疗可能是有利的，但在需要未受损的免疫功能时，可能是有害的。
