Shuai Han, Jiuyang Zhao, Kaiguang Yang, Lihua Zhang, Jianhui Liu, Jingdi Sun
Hemodialysis is one of the most important therapies for patients with uremia, and the dialysis membrane is the predominant factor that impacts the efficiency of dialysis. Here, a protein adsorption on two different membranes is investigated to provide a basis for improving dialysis materials. Two cases treated with the Polyflux 14L low-flux dialyzer and the Polyflux 140H high-flux dialyzers during two continuous therapies are selected. Four used dialyzers from selected patients are infused with C12Im-Cl to elute the adsorbed proteins. Then labeled digested proteins adsorb by Polyflux 140H and Polyflux 14L with 13CD2O and NaCNBD3 (light labeling, L) and CD2O and NaCNBH3 (heavy labeling, H), respectively. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is used to identify the proteins. According to the ratio (Light labeling/Heavy labeling), the eluted proteins are divided into three groups: significantly higher, significantly lower, and no significant differences with a ratio of >2, <0.5, and 0.5–2, respectively. A total of 668 proteins are identified by LC-MS/MS, among which 177 proteins are retained more by the Polyflux 140H membrane (ratio >2), 320 proteins are retained more by the Polyflux 14L membrane (ratio <0.5), and 171 proteins show no significant difference (ratio 0.5–2) between the two types of membranes. Statistical significance is shown in the percentage of adsorbed proteins with an isoelectric point (pI) ranging from 9 to 10 (19.08 versus 7.69%; χ2 = 11.87, p = 0.0006). Proteins with a molecular weight (MW) of 10–15 kDa tend to deposit on Polyflux 140H compared with Polyflux 14L (25 versus 9.23%; χ2 = 18.66, p = 0.0000) and proteins with a MW of 30–60 kDa tend to deposit on Polyflux 14L compared with Polyflux 140H (36.54 versus 22.37%; χ2 = 8.96, p = 0.0028). According to gene ontology analysis, the proteins adsorbed by dialysis membranes are closely related to activation of complement system and the coagulation cascade. The proteins adsorbed by Polyflux 140H and Polyflux 14L show significant differences in PI, MW, and protein class. Proteomic techniques are an effective approach for studying hemodialysis membranes.
