Programmpunkt

08:45

Titel: Increasing magnesium overcomes cytoskeleton storage lesions in cold stored platelet concentrates
ID: VS-17-2
Art: Abstractvortrag
Redezeit: 10 + 5 min
Session:
Blut- und Zellprodukte: neue Verfahren und Strategien
VS-17

Referent: Konstanze Aurich (Greifswald)


Abstract - Text

Offenlegung Interessenkonflikt:

no conflict of interest

Methods

Pooled PC were made from 4 buffy coats of whole blood donors and SSP+ (Maco Pharma), stored for 7 days at room temperature (RT) or at 4°C. Magnesium sulfate was added to cold stored PC in a concentration from 0-8 mM. Platelets from differently stored PC underwent platelet function testing determined as hypotonic shock response (HSR), aggregation ability by light transmission aggregometry (inductors collagen, TRAP6) and measuring the CD62P experession. To evaluate the Mg2+ impact on platelet cytoskeleton we analyzed the mechanical deformability of platelets by real-time deformability cytometry (RT-DC), a method for biomechanical cell characterization. Finally, we determined the integrity of β-tubulin by immunofluorescence microscopy.

Results

HSR as an in vitro indicator of in vivo platelet integrity was reduced in cold stored platelets, but normal in cold stored platelets at 8 mM Mg2+ (day 1: RT 56.4±29.3% vs 4 °C 45.6±11.4% vs 4 °C+8mM Mg2+ 55.2±11.2%). CD62P expression and platelet aggregation response were similar between RT or 4°C stored platelets (p>0.05), higher Mg2+ concentrations had no impact. Conversely, cell deformability was strongly affected by cold storage and normalized by Mg2+ addition (day 1: RT 0.120±0.039 vs 4 °C 0.095±0.041 vs 4°C + 8mM Mg2+ 0.119±0.046). The same applied to β-tubulin: Storing platelets at 4 °C induces disorganization of tubulin. Additional Mg2+ prevents tubulin depolymerization dose dependently with strongest effects > 6mM Mg2+ (Fig.1).

Background

Cold storage of platelet concentrates (PC) has become attractive due to the reduced risk of bacterial proliferation, but in vivo circulation time of cold stored platelets is reduced. Ca2+ release from storage organelles and higher activity of Ca2+ pumps at temperatures <15°C trigger cytoskeleton restructuring processes. This is suppressed by Mg2+ addition, avoiding a shift in Ca2+ hemostasis and cytoskeletal alterations. We report on the impact of additional Mg2+ on platelet cytoskeleton.

Conclusion

Increasing Mg2+ up to 8 mM in platelet additive solution counteracts 4 °C storage lesions in platelets and maintains platelet cytoskeleton structure and biomechanical properties comparable to RT stored platelets.