The Impact of Ventricular Assist Device Biomaterials on Leukocyte Activation

  • Gemma Radley (Discussant)

Activity: Talk or presentationOral presentationResearch


Aim: To evaluate the effect of biomaterials used in ventricular assist devices (VADs) on leukocyte behaviour to identify the most biocompatible. The results will impact future VAD designs to reduce common complications such as thromboembolism and infection. Methods: Discs of biomaterials used in VAD designs - single-crystal sapphire (SAP), silicon nitride (SIN), zirconia toughened-alumina (ZTA) and titanium alloy (TI) - were suspended on polypropylene beads in petri dishes; beads only served as a negative control. Heparinised human peripheral blood was added to each dish and incubated at 37°C on a shaking plate. After 2h, the blood was removed and used for: cell count analysis using the Cell-DYN Ruby haematology analyser; whole blood cultures with 10 ng/mL LPS stimulation for 24hrs to yield supernatants for cytokine analysis using ELISA; and viability and CD62L expression through flow cytometry. The LAL assay for endotoxin detection was used to determine that the responses were from the discs and not contamination. Results: Preliminary data shown as fold change from negative control. Cell viability between the biomaterials (n=3) did not vary but a decrease in leukocyte numbers (n=7) was noted: 0.88±0.06 (SAP); 0.86±0.08 (SIN); 0.90±0.04 (TI); and 0.92±0.05 (ZTA). Activation detected as a decrease in CD62L (n=1) occurred with silicon nitride (0.76 fold from negative control) but not with the other materials. Interleukin-8 (IL-8) concentration in LPS-stimulated samples varies by biomaterial (n=5): 1.06±0.56 (SAP); 1.14±0.37 (SIN); 1.25±0.73 (TI); and 1.51±0.78 (ZTA). Endotoxin tests (n=2) have shown concentrations of less than 0.5 EU/mL in all samples and deemed acceptable. Conclusions: The decrease in leukocyte numbers could be due to the activation and adhesion of leukocytes, in particular monocytes and granulocytes, to the discs and not related to cell death. Silicon nitride so far has shown a greater decrease in leukocyte count, leukocyte activation through CD62L shedding and a higher concentration of IL-8 indicating poorer biocompatibility than the other biomaterials. Ongoing work includes flow cytometry for more detailed analysis of cell activation and microscopy for adhesion.
PeriodMay 2015
Event titleEuropean Society of Cardiology - 2nd Heart Failure Congress
Event typeConference
LocationSeville, SpainShow on map
Degree of RecognitionInternational