Proteomic analysis of protein adsorption capacity of different haemodialysis membranes

Abstract

Protein-adsorptive properties are a key feature of membranes used for haemodialysis treatment. Protein adsorption is vital to the biocompatibility of a membrane material and influences membrane's performance. The object of the present study is to investigate membrane biocompatibility by correlating the adsorbed proteome repertoire with chemical feature of the membrane surfaces. Dialyzers composed of either cellulose triacetate (Sureflux 50 L, effective surface area 0.5 m(2); Nipro Corporation, Japan) or the polysulfone-based helixone (FX40, effective surface area 0.4 m(2); Fresenius Medical Care AG, Germany) materials were employed to develop an ex vivo apparatus to study protein adsorption. Adsorbed proteins were eluted by a strong chaotropic buffer condition and investigated by a proteomic approach. The profiling strategy was based on 2D-electrophoresis separation of desorbed protein coupled to MALDI-TOF/TOF analysis. The total protein adsorption was not significantly different between the two materials. An average of 179 protein spots was visualised for helixone membranes while a map of retained proteins of cellulose triacetate membranes was made up of 239 protein spots. The cellulose triacetate material showed a higher binding capacity for albumin and apolipoprotein. In fact, a number of different protein spots belonging to the gene transcript of albumin were visible in the cellulose triacetate map. In contrast, helixone bound only a small proportion of albumin, while proved to be particularly active in retaining protein associated with the coagulation cascade, such as the fibrinogen isoforms. Our data indicate that proteomic techniques are a useful approach for the investigation of proteins surface-adsorbed onto haemodialysis membranes, and may provide a molecular base for the interpretation of the efficacy and safety of anticoagulation treatment during renal replacement therapy.

Improvement of Urinary Stones Analysis Combining Morphological Analysis and Infrared Spectroscopy

“…Whitlockite, a calcium magnesium orthophosphate (Ca, Mg) 3 (PO 4 ) 2 , is generally found in women with stones associated with chronic urinary tract infections by nonureaseproducing bacteria [15]. Proteins are a common constituent of kidney stones, but at marginal concentrations, that is, less than 2.5% dry weight [16,17]. On the contrary, proteins are much more represented in stones associated with chronic urinary infections as likely in this case.…”

Binding Affinity and Capacity for the Uremic Toxin Indoxyl Sulfate

“…A methodological artifact can be excluded because comparable protein bound fractions of IS were obtained with both ultrafiltration and equilibrium dialysis. Together with protein adsorption onto the semipermeable dialysis membrane [29], ultrafiltration of plasma water leads to an increase of the protein concentration in the retentate and, thus, a shift in the equilibrium. This phenomenon is well known from clinical hemodialysis, especially during post-dilution hemodiafiltration, a dialysis procedure, which combines excess ultrafiltration of plasma water to diffusion, leading to protein concentration within the dialyzer near the membrane surface.…”

Protein adsorption steers blood contact activation on engineered cobalt chromium alloy oxide layers

“…These early events determine the following cascade of biological reactions and conse- 35 quently the long-term success of implants. The ability to modulate surface properties of biomaterials 36 is therefore of considerable clinical significance. 37 Goal of this study was an in-depth understanding of the biological response to cobalt chromium stent 38 alloys with engineered surface oxide layers, which showed altered body reactions in vivo.…”

“…This is not surprising since, during blood con- or labeling of selected proteins [34]. 551 As a first screening step to identify as many proteins as possible 552 and to look for potential proteins of interest, proteins were prote-553 olytically digested, eluted and analysed by mass spectroscopy, 554 analogously to procedures described in the literature [35,36]. Not 555 surprisingly, abundant blood proteins such as albumin, fibrinogen 556 and complement C3 were found in large quantities among the pro-557 teins desorbed from all surfaces ( Fig.…”