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Abstract: PO0929

Protein Loss with Medium Cut-Off and High Flux Dialyzer: A Proteomic Analysis

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis

Authors

  • Wang, Xiaoling, Renal Research Institute, New York, New York, United States
  • Tao, Xia, Renal Research Institute, New York, New York, United States
  • Tapia Silva, Leticia Mirell, Renal Research Institute, New York, New York, United States
  • Patel, Amrish U., Renal Research Institute, New York, New York, United States
  • Hakim, Mohamad I., Renal Research Institute, New York, New York, United States
  • Grobe, Nadja, Renal Research Institute, New York, New York, United States
  • Thijssen, Stephan, Renal Research Institute, New York, New York, United States
  • Kotanko, Peter, Renal Research Institute, New York, New York, United States
Background

Hemodialysis (HD) patients frequently suffer from low serum albumin levels, making dialytic albumin and protein loss a concern. Medium cut-off (MCO) dialysis membranes reportedly show a greater albumin loss compared to high-flux (HiFlux) membranes. To better understand the spectrum of proteins cleared with MCO membranes, we set up an ex vivo dialysis system and perform proteomic analysis of the dialysate.

Methods

Eight liters of human plasma (EDTA added) are split into two 4-liter batches and dialyzed for 4 hrs in single-pass, either with an MCO (Theranova 400) or HiFlux dialyzer (Optiflux F180NR) using a Fresenius 2008T machine. Blood flow was 400 ml/min. Dialysate flow was 600 ml/min for the first 3 hrs and zero for the 4th hr. Ultrafiltration rate was zero for the first 2 hrs and switched to 1 L/hr thereafter. This design allowed us to study three HD modes: diffusion only (2 hrs); diffusion with convection (1 hr); convection only (1 hr). Dialysates were sampled at multiple time points (Fig 1B).

Results

Three µg of initial plasma and 23 µl dialysate were loaded on an SDS-page gel and silver stained (Fig 1A). Lanes 3 and 5 were from MCO, lanes 4 and 6 from HiFlux. Lanes 3 and 4 were collected 15 mins into dialysis, lanes 5 and 6 at 240 mins. Results show that dialysates contain less high molecular weight proteins compared to plasma, and MCO dialysates contain much more proteins compared to HiFlux dialysates. The strong band at ~62 kD is most likely albumin. Using mass spectroscopy, we can identify 56 different protein species in MCO dialysate.
Dialysate protein levels (measured by Bradford assay) with the 3 dialytic modalities are shown in Fig 1B, the total protein losses are listed in Fig 1C. The ratio of protein loss between MCO and HiFlux dialyzers is 17-fold in the convection only mode.

Conclusion

Our results show a higher diffuse and convective protein loss with MCO compared to HiFlux membranes. Further characterization and quantitation of proteins cleared in vivo during HD are necessary to better understand the clinical impact of our ex vivo observations.

Figure 1: dialysate protein analysis.

Funding

  • Commercial Support